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1616 | serge | 1 | /* |
2 | This is a version (aka dlmalloc) of malloc/free/realloc written by |
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3 | Doug Lea and released to the public domain, as explained at |
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3297 | Serge | 4 | http://creativecommons.org/publicdomain/zero/1.0/ Send questions, |
1616 | serge | 5 | comments, complaints, performance data, etc to dl@cs.oswego.edu |
6 | |||
3297 | Serge | 7 | * Version 2.8.6 Wed Aug 29 06:57:58 2012 Doug Lea |
1616 | serge | 8 | Note: There may be an updated version of this malloc obtainable at |
9 | ftp://gee.cs.oswego.edu/pub/misc/malloc.c |
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10 | Check before installing! |
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11 | |||
12 | * Quickstart |
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13 | |||
14 | This library is all in one file to simplify the most common usage: |
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15 | ftp it, compile it (-O3), and link it into another program. All of |
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16 | the compile-time options default to reasonable values for use on |
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17 | most platforms. You might later want to step through various |
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18 | compile-time and dynamic tuning options. |
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19 | |||
20 | For convenience, an include file for code using this malloc is at: |
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3297 | Serge | 21 | ftp://gee.cs.oswego.edu/pub/misc/malloc-2.8.6.h |
1616 | serge | 22 | You don't really need this .h file unless you call functions not |
23 | defined in your system include files. The .h file contains only the |
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24 | excerpts from this file needed for using this malloc on ANSI C/C++ |
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25 | systems, so long as you haven't changed compile-time options about |
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26 | naming and tuning parameters. If you do, then you can create your |
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27 | own malloc.h that does include all settings by cutting at the point |
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28 | indicated below. Note that you may already by default be using a C |
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29 | library containing a malloc that is based on some version of this |
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30 | malloc (for example in linux). You might still want to use the one |
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31 | in this file to customize settings or to avoid overheads associated |
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32 | with library versions. |
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33 | |||
3297 | Serge | 34 | * Vital statistics: |
35 | |||
36 | Supported pointer/size_t representation: 4 or 8 bytes |
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37 | size_t MUST be an unsigned type of the same width as |
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38 | pointers. (If you are using an ancient system that declares |
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39 | size_t as a signed type, or need it to be a different width |
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40 | than pointers, you can use a previous release of this malloc |
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41 | (e.g. 2.7.2) supporting these.) |
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42 | |||
43 | Alignment: 8 bytes (minimum) |
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44 | This suffices for nearly all current machines and C compilers. |
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45 | However, you can define MALLOC_ALIGNMENT to be wider than this |
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46 | if necessary (up to 128bytes), at the expense of using more space. |
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47 | |||
48 | Minimum overhead per allocated chunk: 4 or 8 bytes (if 4byte sizes) |
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49 | 8 or 16 bytes (if 8byte sizes) |
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50 | Each malloced chunk has a hidden word of overhead holding size |
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51 | and status information, and additional cross-check word |
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52 | if FOOTERS is defined. |
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53 | |||
54 | Minimum allocated size: 4-byte ptrs: 16 bytes (including overhead) |
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55 | 8-byte ptrs: 32 bytes (including overhead) |
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56 | |||
57 | Even a request for zero bytes (i.e., malloc(0)) returns a |
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58 | pointer to something of the minimum allocatable size. |
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59 | The maximum overhead wastage (i.e., number of extra bytes |
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60 | allocated than were requested in malloc) is less than or equal |
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61 | to the minimum size, except for requests >= mmap_threshold that |
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62 | are serviced via mmap(), where the worst case wastage is about |
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63 | 32 bytes plus the remainder from a system page (the minimal |
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64 | mmap unit); typically 4096 or 8192 bytes. |
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65 | |||
66 | Security: static-safe; optionally more or less |
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67 | The "security" of malloc refers to the ability of malicious |
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68 | code to accentuate the effects of errors (for example, freeing |
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69 | space that is not currently malloc'ed or overwriting past the |
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70 | ends of chunks) in code that calls malloc. This malloc |
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71 | guarantees not to modify any memory locations below the base of |
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72 | heap, i.e., static variables, even in the presence of usage |
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73 | errors. The routines additionally detect most improper frees |
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74 | and reallocs. All this holds as long as the static bookkeeping |
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75 | for malloc itself is not corrupted by some other means. This |
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76 | is only one aspect of security -- these checks do not, and |
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77 | cannot, detect all possible programming errors. |
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78 | |||
79 | If FOOTERS is defined nonzero, then each allocated chunk |
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80 | carries an additional check word to verify that it was malloced |
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81 | from its space. These check words are the same within each |
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82 | execution of a program using malloc, but differ across |
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83 | executions, so externally crafted fake chunks cannot be |
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84 | freed. This improves security by rejecting frees/reallocs that |
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85 | could corrupt heap memory, in addition to the checks preventing |
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86 | writes to statics that are always on. This may further improve |
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87 | security at the expense of time and space overhead. (Note that |
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88 | FOOTERS may also be worth using with MSPACES.) |
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89 | |||
90 | By default detected errors cause the program to abort (calling |
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91 | "abort()"). You can override this to instead proceed past |
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92 | errors by defining PROCEED_ON_ERROR. In this case, a bad free |
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93 | has no effect, and a malloc that encounters a bad address |
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94 | caused by user overwrites will ignore the bad address by |
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95 | dropping pointers and indices to all known memory. This may |
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96 | be appropriate for programs that should continue if at all |
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97 | possible in the face of programming errors, although they may |
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98 | run out of memory because dropped memory is never reclaimed. |
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99 | |||
100 | If you don't like either of these options, you can define |
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101 | CORRUPTION_ERROR_ACTION and USAGE_ERROR_ACTION to do anything |
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102 | else. And if if you are sure that your program using malloc has |
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103 | no errors or vulnerabilities, you can define INSECURE to 1, |
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104 | which might (or might not) provide a small performance improvement. |
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105 | |||
106 | It is also possible to limit the maximum total allocatable |
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107 | space, using malloc_set_footprint_limit. This is not |
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108 | designed as a security feature in itself (calls to set limits |
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109 | are not screened or privileged), but may be useful as one |
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110 | aspect of a secure implementation. |
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111 | |||
112 | Thread-safety: NOT thread-safe unless USE_LOCKS defined non-zero |
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113 | When USE_LOCKS is defined, each public call to malloc, free, |
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114 | etc is surrounded with a lock. By default, this uses a plain |
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115 | pthread mutex, win32 critical section, or a spin-lock if if |
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116 | available for the platform and not disabled by setting |
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117 | USE_SPIN_LOCKS=0. However, if USE_RECURSIVE_LOCKS is defined, |
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118 | recursive versions are used instead (which are not required for |
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119 | base functionality but may be needed in layered extensions). |
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120 | Using a global lock is not especially fast, and can be a major |
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121 | bottleneck. It is designed only to provide minimal protection |
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122 | in concurrent environments, and to provide a basis for |
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123 | extensions. If you are using malloc in a concurrent program, |
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124 | consider instead using nedmalloc |
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125 | (http://www.nedprod.com/programs/portable/nedmalloc/) or |
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126 | ptmalloc (See http://www.malloc.de), which are derived from |
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127 | versions of this malloc. |
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128 | |||
129 | System requirements: Any combination of MORECORE and/or MMAP/MUNMAP |
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130 | This malloc can use unix sbrk or any emulation (invoked using |
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131 | the CALL_MORECORE macro) and/or mmap/munmap or any emulation |
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132 | (invoked using CALL_MMAP/CALL_MUNMAP) to get and release system |
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133 | memory. On most unix systems, it tends to work best if both |
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134 | MORECORE and MMAP are enabled. On Win32, it uses emulations |
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135 | based on VirtualAlloc. It also uses common C library functions |
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136 | like memset. |
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137 | |||
138 | Compliance: I believe it is compliant with the Single Unix Specification |
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139 | (See http://www.unix.org). Also SVID/XPG, ANSI C, and probably |
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140 | others as well. |
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141 | |||
142 | * Overview of algorithms |
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143 | |||
144 | This is not the fastest, most space-conserving, most portable, or |
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145 | most tunable malloc ever written. However it is among the fastest |
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146 | while also being among the most space-conserving, portable and |
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147 | tunable. Consistent balance across these factors results in a good |
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148 | general-purpose allocator for malloc-intensive programs. |
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149 | |||
150 | In most ways, this malloc is a best-fit allocator. Generally, it |
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151 | chooses the best-fitting existing chunk for a request, with ties |
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152 | broken in approximately least-recently-used order. (This strategy |
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153 | normally maintains low fragmentation.) However, for requests less |
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154 | than 256bytes, it deviates from best-fit when there is not an |
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155 | exactly fitting available chunk by preferring to use space adjacent |
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156 | to that used for the previous small request, as well as by breaking |
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157 | ties in approximately most-recently-used order. (These enhance |
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158 | locality of series of small allocations.) And for very large requests |
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159 | (>= 256Kb by default), it relies on system memory mapping |
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160 | facilities, if supported. (This helps avoid carrying around and |
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161 | possibly fragmenting memory used only for large chunks.) |
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162 | |||
163 | All operations (except malloc_stats and mallinfo) have execution |
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164 | times that are bounded by a constant factor of the number of bits in |
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165 | a size_t, not counting any clearing in calloc or copying in realloc, |
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166 | or actions surrounding MORECORE and MMAP that have times |
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167 | proportional to the number of non-contiguous regions returned by |
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168 | system allocation routines, which is often just 1. In real-time |
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169 | applications, you can optionally suppress segment traversals using |
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170 | NO_SEGMENT_TRAVERSAL, which assures bounded execution even when |
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171 | system allocators return non-contiguous spaces, at the typical |
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172 | expense of carrying around more memory and increased fragmentation. |
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173 | |||
174 | The implementation is not very modular and seriously overuses |
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175 | macros. Perhaps someday all C compilers will do as good a job |
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176 | inlining modular code as can now be done by brute-force expansion, |
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177 | but now, enough of them seem not to. |
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178 | |||
179 | Some compilers issue a lot of warnings about code that is |
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180 | dead/unreachable only on some platforms, and also about intentional |
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181 | uses of negation on unsigned types. All known cases of each can be |
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182 | ignored. |
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183 | |||
184 | For a longer but out of date high-level description, see |
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185 | http://gee.cs.oswego.edu/dl/html/malloc.html |
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186 | |||
187 | * MSPACES |
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188 | If MSPACES is defined, then in addition to malloc, free, etc., |
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189 | this file also defines mspace_malloc, mspace_free, etc. These |
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190 | are versions of malloc routines that take an "mspace" argument |
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191 | obtained using create_mspace, to control all internal bookkeeping. |
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192 | If ONLY_MSPACES is defined, only these versions are compiled. |
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193 | So if you would like to use this allocator for only some allocations, |
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194 | and your system malloc for others, you can compile with |
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195 | ONLY_MSPACES and then do something like... |
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196 | static mspace mymspace = create_mspace(0,0); // for example |
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197 | #define mymalloc(bytes) mspace_malloc(mymspace, bytes) |
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198 | |||
199 | (Note: If you only need one instance of an mspace, you can instead |
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200 | use "USE_DL_PREFIX" to relabel the global malloc.) |
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201 | |||
202 | You can similarly create thread-local allocators by storing |
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203 | mspaces as thread-locals. For example: |
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204 | static __thread mspace tlms = 0; |
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205 | void* tlmalloc(size_t bytes) { |
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206 | if (tlms == 0) tlms = create_mspace(0, 0); |
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207 | return mspace_malloc(tlms, bytes); |
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208 | } |
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209 | void tlfree(void* mem) { mspace_free(tlms, mem); } |
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210 | |||
211 | Unless FOOTERS is defined, each mspace is completely independent. |
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212 | You cannot allocate from one and free to another (although |
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213 | conformance is only weakly checked, so usage errors are not always |
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214 | caught). If FOOTERS is defined, then each chunk carries around a tag |
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215 | indicating its originating mspace, and frees are directed to their |
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216 | originating spaces. Normally, this requires use of locks. |
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217 | |||
218 | ------------------------- Compile-time options --------------------------- |
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219 | |||
220 | Be careful in setting #define values for numerical constants of type |
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221 | size_t. On some systems, literal values are not automatically extended |
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222 | to size_t precision unless they are explicitly casted. You can also |
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223 | use the symbolic values MAX_SIZE_T, SIZE_T_ONE, etc below. |
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224 | |||
225 | WIN32 default: defined if _WIN32 defined |
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226 | Defining WIN32 sets up defaults for MS environment and compilers. |
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227 | Otherwise defaults are for unix. Beware that there seem to be some |
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228 | cases where this malloc might not be a pure drop-in replacement for |
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229 | Win32 malloc: Random-looking failures from Win32 GDI API's (eg; |
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230 | SetDIBits()) may be due to bugs in some video driver implementations |
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231 | when pixel buffers are malloc()ed, and the region spans more than |
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232 | one VirtualAlloc()ed region. Because dlmalloc uses a small (64Kb) |
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233 | default granularity, pixel buffers may straddle virtual allocation |
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234 | regions more often than when using the Microsoft allocator. You can |
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235 | avoid this by using VirtualAlloc() and VirtualFree() for all pixel |
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236 | buffers rather than using malloc(). If this is not possible, |
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237 | recompile this malloc with a larger DEFAULT_GRANULARITY. Note: |
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238 | in cases where MSC and gcc (cygwin) are known to differ on WIN32, |
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239 | conditions use _MSC_VER to distinguish them. |
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240 | |||
241 | DLMALLOC_EXPORT default: extern |
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242 | Defines how public APIs are declared. If you want to export via a |
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243 | Windows DLL, you might define this as |
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244 | #define DLMALLOC_EXPORT extern __declspec(dllexport) |
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245 | If you want a POSIX ELF shared object, you might use |
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246 | #define DLMALLOC_EXPORT extern __attribute__((visibility("default"))) |
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247 | |||
248 | MALLOC_ALIGNMENT default: (size_t)(2 * sizeof(void *)) |
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249 | Controls the minimum alignment for malloc'ed chunks. It must be a |
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250 | power of two and at least 8, even on machines for which smaller |
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251 | alignments would suffice. It may be defined as larger than this |
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252 | though. Note however that code and data structures are optimized for |
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253 | the case of 8-byte alignment. |
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254 | |||
255 | MSPACES default: 0 (false) |
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256 | If true, compile in support for independent allocation spaces. |
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257 | This is only supported if HAVE_MMAP is true. |
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258 | |||
259 | ONLY_MSPACES default: 0 (false) |
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260 | If true, only compile in mspace versions, not regular versions. |
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261 | |||
262 | USE_LOCKS default: 0 (false) |
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263 | Causes each call to each public routine to be surrounded with |
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264 | pthread or WIN32 mutex lock/unlock. (If set true, this can be |
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265 | overridden on a per-mspace basis for mspace versions.) If set to a |
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266 | non-zero value other than 1, locks are used, but their |
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267 | implementation is left out, so lock functions must be supplied manually, |
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268 | as described below. |
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269 | |||
270 | USE_SPIN_LOCKS default: 1 iff USE_LOCKS and spin locks available |
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271 | If true, uses custom spin locks for locking. This is currently |
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272 | supported only gcc >= 4.1, older gccs on x86 platforms, and recent |
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273 | MS compilers. Otherwise, posix locks or win32 critical sections are |
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274 | used. |
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275 | |||
276 | USE_RECURSIVE_LOCKS default: not defined |
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277 | If defined nonzero, uses recursive (aka reentrant) locks, otherwise |
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278 | uses plain mutexes. This is not required for malloc proper, but may |
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279 | be needed for layered allocators such as nedmalloc. |
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280 | |||
281 | LOCK_AT_FORK default: not defined |
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282 | If defined nonzero, performs pthread_atfork upon initialization |
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283 | to initialize child lock while holding parent lock. The implementation |
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284 | assumes that pthread locks (not custom locks) are being used. In other |
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285 | cases, you may need to customize the implementation. |
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286 | |||
287 | FOOTERS default: 0 |
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288 | If true, provide extra checking and dispatching by placing |
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289 | information in the footers of allocated chunks. This adds |
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290 | space and time overhead. |
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291 | |||
292 | INSECURE default: 0 |
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293 | If true, omit checks for usage errors and heap space overwrites. |
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294 | |||
295 | USE_DL_PREFIX default: NOT defined |
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296 | Causes compiler to prefix all public routines with the string 'dl'. |
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297 | This can be useful when you only want to use this malloc in one part |
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298 | of a program, using your regular system malloc elsewhere. |
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299 | |||
300 | MALLOC_INSPECT_ALL default: NOT defined |
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301 | If defined, compiles malloc_inspect_all and mspace_inspect_all, that |
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302 | perform traversal of all heap space. Unless access to these |
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303 | functions is otherwise restricted, you probably do not want to |
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304 | include them in secure implementations. |
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305 | |||
306 | ABORT default: defined as abort() |
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307 | Defines how to abort on failed checks. On most systems, a failed |
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308 | check cannot die with an "assert" or even print an informative |
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309 | message, because the underlying print routines in turn call malloc, |
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310 | which will fail again. Generally, the best policy is to simply call |
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311 | abort(). It's not very useful to do more than this because many |
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312 | errors due to overwriting will show up as address faults (null, odd |
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313 | addresses etc) rather than malloc-triggered checks, so will also |
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314 | abort. Also, most compilers know that abort() does not return, so |
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315 | can better optimize code conditionally calling it. |
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316 | |||
317 | PROCEED_ON_ERROR default: defined as 0 (false) |
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318 | Controls whether detected bad addresses cause them to bypassed |
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319 | rather than aborting. If set, detected bad arguments to free and |
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320 | realloc are ignored. And all bookkeeping information is zeroed out |
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321 | upon a detected overwrite of freed heap space, thus losing the |
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322 | ability to ever return it from malloc again, but enabling the |
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323 | application to proceed. If PROCEED_ON_ERROR is defined, the |
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324 | static variable malloc_corruption_error_count is compiled in |
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325 | and can be examined to see if errors have occurred. This option |
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326 | generates slower code than the default abort policy. |
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327 | |||
328 | DEBUG default: NOT defined |
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329 | The DEBUG setting is mainly intended for people trying to modify |
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330 | this code or diagnose problems when porting to new platforms. |
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331 | However, it may also be able to better isolate user errors than just |
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332 | using runtime checks. The assertions in the check routines spell |
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333 | out in more detail the assumptions and invariants underlying the |
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334 | algorithms. The checking is fairly extensive, and will slow down |
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335 | execution noticeably. Calling malloc_stats or mallinfo with DEBUG |
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336 | set will attempt to check every non-mmapped allocated and free chunk |
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337 | in the course of computing the summaries. |
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338 | |||
339 | ABORT_ON_ASSERT_FAILURE default: defined as 1 (true) |
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340 | Debugging assertion failures can be nearly impossible if your |
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341 | version of the assert macro causes malloc to be called, which will |
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342 | lead to a cascade of further failures, blowing the runtime stack. |
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343 | ABORT_ON_ASSERT_FAILURE cause assertions failures to call abort(), |
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344 | which will usually make debugging easier. |
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345 | |||
346 | MALLOC_FAILURE_ACTION default: sets errno to ENOMEM, or no-op on win32 |
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347 | The action to take before "return 0" when malloc fails to be able to |
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348 | return memory because there is none available. |
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349 | |||
350 | HAVE_MORECORE default: 1 (true) unless win32 or ONLY_MSPACES |
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351 | True if this system supports sbrk or an emulation of it. |
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352 | |||
353 | MORECORE default: sbrk |
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354 | The name of the sbrk-style system routine to call to obtain more |
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355 | memory. See below for guidance on writing custom MORECORE |
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356 | functions. The type of the argument to sbrk/MORECORE varies across |
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357 | systems. It cannot be size_t, because it supports negative |
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358 | arguments, so it is normally the signed type of the same width as |
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359 | size_t (sometimes declared as "intptr_t"). It doesn't much matter |
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360 | though. Internally, we only call it with arguments less than half |
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361 | the max value of a size_t, which should work across all reasonable |
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362 | possibilities, although sometimes generating compiler warnings. |
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363 | |||
364 | MORECORE_CONTIGUOUS default: 1 (true) if HAVE_MORECORE |
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365 | If true, take advantage of fact that consecutive calls to MORECORE |
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366 | with positive arguments always return contiguous increasing |
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367 | addresses. This is true of unix sbrk. It does not hurt too much to |
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368 | set it true anyway, since malloc copes with non-contiguities. |
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369 | Setting it false when definitely non-contiguous saves time |
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370 | and possibly wasted space it would take to discover this though. |
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371 | |||
372 | MORECORE_CANNOT_TRIM default: NOT defined |
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373 | True if MORECORE cannot release space back to the system when given |
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374 | negative arguments. This is generally necessary only if you are |
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375 | using a hand-crafted MORECORE function that cannot handle negative |
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376 | arguments. |
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377 | |||
378 | NO_SEGMENT_TRAVERSAL default: 0 |
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379 | If non-zero, suppresses traversals of memory segments |
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380 | returned by either MORECORE or CALL_MMAP. This disables |
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381 | merging of segments that are contiguous, and selectively |
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382 | releasing them to the OS if unused, but bounds execution times. |
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383 | |||
384 | HAVE_MMAP default: 1 (true) |
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385 | True if this system supports mmap or an emulation of it. If so, and |
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386 | HAVE_MORECORE is not true, MMAP is used for all system |
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387 | allocation. If set and HAVE_MORECORE is true as well, MMAP is |
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388 | primarily used to directly allocate very large blocks. It is also |
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389 | used as a backup strategy in cases where MORECORE fails to provide |
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390 | space from system. Note: A single call to MUNMAP is assumed to be |
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391 | able to unmap memory that may have be allocated using multiple calls |
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392 | to MMAP, so long as they are adjacent. |
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393 | |||
394 | HAVE_MREMAP default: 1 on linux, else 0 |
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395 | If true realloc() uses mremap() to re-allocate large blocks and |
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396 | extend or shrink allocation spaces. |
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397 | |||
398 | MMAP_CLEARS default: 1 except on WINCE. |
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399 | True if mmap clears memory so calloc doesn't need to. This is true |
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400 | for standard unix mmap using /dev/zero and on WIN32 except for WINCE. |
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401 | |||
402 | USE_BUILTIN_FFS default: 0 (i.e., not used) |
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403 | Causes malloc to use the builtin ffs() function to compute indices. |
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404 | Some compilers may recognize and intrinsify ffs to be faster than the |
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405 | supplied C version. Also, the case of x86 using gcc is special-cased |
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406 | to an asm instruction, so is already as fast as it can be, and so |
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407 | this setting has no effect. Similarly for Win32 under recent MS compilers. |
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408 | (On most x86s, the asm version is only slightly faster than the C version.) |
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409 | |||
410 | malloc_getpagesize default: derive from system includes, or 4096. |
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411 | The system page size. To the extent possible, this malloc manages |
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412 | memory from the system in page-size units. This may be (and |
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413 | usually is) a function rather than a constant. This is ignored |
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414 | if WIN32, where page size is determined using getSystemInfo during |
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415 | initialization. |
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416 | |||
417 | USE_DEV_RANDOM default: 0 (i.e., not used) |
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418 | Causes malloc to use /dev/random to initialize secure magic seed for |
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419 | stamping footers. Otherwise, the current time is used. |
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420 | |||
421 | NO_MALLINFO default: 0 |
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422 | If defined, don't compile "mallinfo". This can be a simple way |
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423 | of dealing with mismatches between system declarations and |
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424 | those in this file. |
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425 | |||
426 | MALLINFO_FIELD_TYPE default: size_t |
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427 | The type of the fields in the mallinfo struct. This was originally |
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428 | defined as "int" in SVID etc, but is more usefully defined as |
||
429 | size_t. The value is used only if HAVE_USR_INCLUDE_MALLOC_H is not set |
||
430 | |||
431 | NO_MALLOC_STATS default: 0 |
||
432 | If defined, don't compile "malloc_stats". This avoids calls to |
||
433 | fprintf and bringing in stdio dependencies you might not want. |
||
434 | |||
435 | REALLOC_ZERO_BYTES_FREES default: not defined |
||
436 | This should be set if a call to realloc with zero bytes should |
||
437 | be the same as a call to free. Some people think it should. Otherwise, |
||
438 | since this malloc returns a unique pointer for malloc(0), so does |
||
439 | realloc(p, 0). |
||
440 | |||
441 | LACKS_UNISTD_H, LACKS_FCNTL_H, LACKS_SYS_PARAM_H, LACKS_SYS_MMAN_H |
||
442 | LACKS_STRINGS_H, LACKS_STRING_H, LACKS_SYS_TYPES_H, LACKS_ERRNO_H |
||
443 | LACKS_STDLIB_H LACKS_SCHED_H LACKS_TIME_H default: NOT defined unless on WIN32 |
||
444 | Define these if your system does not have these header files. |
||
445 | You might need to manually insert some of the declarations they provide. |
||
446 | |||
447 | DEFAULT_GRANULARITY default: page size if MORECORE_CONTIGUOUS, |
||
448 | system_info.dwAllocationGranularity in WIN32, |
||
449 | otherwise 64K. |
||
450 | Also settable using mallopt(M_GRANULARITY, x) |
||
451 | The unit for allocating and deallocating memory from the system. On |
||
452 | most systems with contiguous MORECORE, there is no reason to |
||
453 | make this more than a page. However, systems with MMAP tend to |
||
454 | either require or encourage larger granularities. You can increase |
||
455 | this value to prevent system allocation functions to be called so |
||
456 | often, especially if they are slow. The value must be at least one |
||
457 | page and must be a power of two. Setting to 0 causes initialization |
||
458 | to either page size or win32 region size. (Note: In previous |
||
459 | versions of malloc, the equivalent of this option was called |
||
460 | "TOP_PAD") |
||
461 | |||
462 | DEFAULT_TRIM_THRESHOLD default: 2MB |
||
463 | Also settable using mallopt(M_TRIM_THRESHOLD, x) |
||
464 | The maximum amount of unused top-most memory to keep before |
||
465 | releasing via malloc_trim in free(). Automatic trimming is mainly |
||
466 | useful in long-lived programs using contiguous MORECORE. Because |
||
467 | trimming via sbrk can be slow on some systems, and can sometimes be |
||
468 | wasteful (in cases where programs immediately afterward allocate |
||
469 | more large chunks) the value should be high enough so that your |
||
470 | overall system performance would improve by releasing this much |
||
471 | memory. As a rough guide, you might set to a value close to the |
||
472 | average size of a process (program) running on your system. |
||
473 | Releasing this much memory would allow such a process to run in |
||
474 | memory. Generally, it is worth tuning trim thresholds when a |
||
475 | program undergoes phases where several large chunks are allocated |
||
476 | and released in ways that can reuse each other's storage, perhaps |
||
477 | mixed with phases where there are no such chunks at all. The trim |
||
478 | value must be greater than page size to have any useful effect. To |
||
479 | disable trimming completely, you can set to MAX_SIZE_T. Note that the trick |
||
480 | some people use of mallocing a huge space and then freeing it at |
||
481 | program startup, in an attempt to reserve system memory, doesn't |
||
482 | have the intended effect under automatic trimming, since that memory |
||
483 | will immediately be returned to the system. |
||
484 | |||
485 | DEFAULT_MMAP_THRESHOLD default: 256K |
||
486 | Also settable using mallopt(M_MMAP_THRESHOLD, x) |
||
487 | The request size threshold for using MMAP to directly service a |
||
488 | request. Requests of at least this size that cannot be allocated |
||
489 | using already-existing space will be serviced via mmap. (If enough |
||
490 | normal freed space already exists it is used instead.) Using mmap |
||
491 | segregates relatively large chunks of memory so that they can be |
||
492 | individually obtained and released from the host system. A request |
||
493 | serviced through mmap is never reused by any other request (at least |
||
494 | not directly; the system may just so happen to remap successive |
||
495 | requests to the same locations). Segregating space in this way has |
||
496 | the benefits that: Mmapped space can always be individually released |
||
497 | back to the system, which helps keep the system level memory demands |
||
498 | of a long-lived program low. Also, mapped memory doesn't become |
||
499 | `locked' between other chunks, as can happen with normally allocated |
||
500 | chunks, which means that even trimming via malloc_trim would not |
||
501 | release them. However, it has the disadvantage that the space |
||
502 | cannot be reclaimed, consolidated, and then used to service later |
||
503 | requests, as happens with normal chunks. The advantages of mmap |
||
504 | nearly always outweigh disadvantages for "large" chunks, but the |
||
505 | value of "large" may vary across systems. The default is an |
||
506 | empirically derived value that works well in most systems. You can |
||
507 | disable mmap by setting to MAX_SIZE_T. |
||
508 | |||
509 | MAX_RELEASE_CHECK_RATE default: 4095 unless not HAVE_MMAP |
||
510 | The number of consolidated frees between checks to release |
||
511 | unused segments when freeing. When using non-contiguous segments, |
||
512 | especially with multiple mspaces, checking only for topmost space |
||
513 | doesn't always suffice to trigger trimming. To compensate for this, |
||
514 | free() will, with a period of MAX_RELEASE_CHECK_RATE (or the |
||
515 | current number of segments, if greater) try to release unused |
||
516 | segments to the OS when freeing chunks that result in |
||
517 | consolidation. The best value for this parameter is a compromise |
||
518 | between slowing down frees with relatively costly checks that |
||
519 | rarely trigger versus holding on to unused memory. To effectively |
||
520 | disable, set to MAX_SIZE_T. This may lead to a very slight speed |
||
521 | improvement at the expense of carrying around more memory. |
||
1616 | serge | 522 | */ |
523 | |||
524 | #include |
||
5270 | serge | 525 | #include |
1616 | serge | 526 | #include |
527 | |||
3297 | Serge | 528 | /* Version identifier to allow people to support multiple versions */ |
529 | #ifndef DLMALLOC_VERSION |
||
530 | #define DLMALLOC_VERSION 20806 |
||
531 | #endif /* DLMALLOC_VERSION */ |
||
1616 | serge | 532 | |
533 | |||
3297 | Serge | 534 | /* |
535 | malloc(size_t n) |
||
536 | Returns a pointer to a newly allocated chunk of at least n bytes, or |
||
537 | null if no space is available, in which case errno is set to ENOMEM |
||
538 | on ANSI C systems. |
||
1616 | serge | 539 | |
3297 | Serge | 540 | If n is zero, malloc returns a minimum-sized chunk. (The minimum |
541 | size is 16 bytes on most 32bit systems, and 32 bytes on 64bit |
||
542 | systems.) Note that size_t is an unsigned type, so calls with |
||
543 | arguments that would be negative if signed are interpreted as |
||
544 | requests for huge amounts of space, which will often fail. The |
||
545 | maximum supported value of n differs across systems, but is in all |
||
546 | cases less than the maximum representable value of a size_t. |
||
547 | */ |
||
1616 | serge | 548 | |
3297 | Serge | 549 | /* |
550 | free(void* p) |
||
551 | Releases the chunk of memory pointed to by p, that had been previously |
||
552 | allocated using malloc or a related routine such as realloc. |
||
553 | It has no effect if p is null. If p was not malloced or already |
||
554 | freed, free(p) will by default cause the current program to abort. |
||
555 | */ |
||
1616 | serge | 556 | |
3297 | Serge | 557 | /* |
558 | calloc(size_t n_elements, size_t element_size); |
||
559 | Returns a pointer to n_elements * element_size bytes, with all locations |
||
560 | set to zero. |
||
561 | */ |
||
562 | |||
563 | /* |
||
564 | realloc(void* p, size_t n) |
||
565 | Returns a pointer to a chunk of size n that contains the same data |
||
566 | as does chunk p up to the minimum of (n, p's size) bytes, or null |
||
567 | if no space is available. |
||
568 | |||
569 | The returned pointer may or may not be the same as p. The algorithm |
||
570 | prefers extending p in most cases when possible, otherwise it |
||
571 | employs the equivalent of a malloc-copy-free sequence. |
||
572 | |||
573 | If p is null, realloc is equivalent to malloc. |
||
574 | |||
575 | If space is not available, realloc returns null, errno is set (if on |
||
576 | ANSI) and p is NOT freed. |
||
577 | |||
578 | if n is for fewer bytes than already held by p, the newly unused |
||
579 | space is lopped off and freed if possible. realloc with a size |
||
580 | argument of zero (re)allocates a minimum-sized chunk. |
||
581 | |||
582 | The old unix realloc convention of allowing the last-free'd chunk |
||
583 | to be used as an argument to realloc is not supported. |
||
584 | */ |
||
585 | /* |
||
586 | memalign(size_t alignment, size_t n); |
||
587 | Returns a pointer to a newly allocated chunk of n bytes, aligned |
||
588 | in accord with the alignment argument. |
||
589 | |||
590 | The alignment argument should be a power of two. If the argument is |
||
591 | not a power of two, the nearest greater power is used. |
||
592 | 8-byte alignment is guaranteed by normal malloc calls, so don't |
||
593 | bother calling memalign with an argument of 8 or less. |
||
594 | |||
595 | Overreliance on memalign is a sure way to fragment space. |
||
596 | */ |
||
597 | |||
598 | |||
599 | #define DEBUG 1 |
||
600 | |||
601 | |||
602 | |||
603 | |||
604 | |||
605 | |||
606 | |||
607 | |||
608 | |||
609 | |||
610 | |||
611 | |||
612 | #define assert(x) |
||
613 | |||
1616 | serge | 614 | #define MAX_SIZE_T (~(size_t)0) |
615 | |||
3297 | Serge | 616 | #define CALL_DIRECT_MMAP(s) MMAP_DEFAULT(s) |
617 | |||
618 | /* ------------------- size_t and alignment properties -------------------- */ |
||
619 | |||
1616 | serge | 620 | /* The byte and bit size of a size_t */ |
621 | #define SIZE_T_SIZE (sizeof(size_t)) |
||
622 | #define SIZE_T_BITSIZE (sizeof(size_t) << 3) |
||
623 | |||
624 | /* Some constants coerced to size_t */ |
||
625 | /* Annoying but necessary to avoid errors on some platforms */ |
||
626 | #define SIZE_T_ZERO ((size_t)0) |
||
627 | #define SIZE_T_ONE ((size_t)1) |
||
628 | #define SIZE_T_TWO ((size_t)2) |
||
629 | #define SIZE_T_FOUR ((size_t)4) |
||
630 | #define TWO_SIZE_T_SIZES (SIZE_T_SIZE<<1) |
||
631 | #define FOUR_SIZE_T_SIZES (SIZE_T_SIZE<<2) |
||
632 | #define SIX_SIZE_T_SIZES (FOUR_SIZE_T_SIZES+TWO_SIZE_T_SIZES) |
||
633 | #define HALF_MAX_SIZE_T (MAX_SIZE_T / 2U) |
||
634 | |||
635 | #define USE_LOCK_BIT (2U) |
||
636 | #define USE_MMAP_BIT (SIZE_T_ONE) |
||
637 | #define USE_NONCONTIGUOUS_BIT (4U) |
||
638 | |||
639 | /* segment bit set in create_mspace_with_base */ |
||
640 | #define EXTERN_BIT (8U) |
||
641 | |||
642 | #define HAVE_MMAP 1 |
||
3297 | Serge | 643 | #define HAVE_MORECORE 0 |
644 | #define MORECORE_CANNOT_TRIM 1 |
||
1616 | serge | 645 | #define CALL_MMAP(s) MMAP_DEFAULT(s) |
646 | #define CALL_MUNMAP(a, s) MUNMAP_DEFAULT((a), (s)) |
||
647 | #define CALL_MREMAP(addr, osz, nsz, mv) MFAIL |
||
648 | #define MAX_RELEASE_CHECK_RATE 4095 |
||
649 | #define NO_SEGMENT_TRAVERSAL 1 |
||
650 | #define MALLOC_ALIGNMENT ((size_t)8U) |
||
651 | #define CHUNK_OVERHEAD (SIZE_T_SIZE) |
||
7143 | serge | 652 | #define DEFAULT_GRANULARITY ((size_t)256U * (size_t)1024U) |
653 | #define DEFAULT_MMAP_THRESHOLD ((size_t)1024U * (size_t)1024U) |
||
654 | #define DEFAULT_TRIM_THRESHOLD ((size_t)2048U * (size_t)1024U) |
||
1616 | serge | 655 | |
656 | /* The bit mask value corresponding to MALLOC_ALIGNMENT */ |
||
657 | #define CHUNK_ALIGN_MASK (MALLOC_ALIGNMENT - SIZE_T_ONE) |
||
658 | |||
659 | /* True if address a has acceptable alignment */ |
||
660 | #define is_aligned(A) (((size_t)((A)) & (CHUNK_ALIGN_MASK)) == 0) |
||
661 | |||
662 | /* the number of bytes to offset an address to align it */ |
||
663 | #define align_offset(A)\ |
||
664 | ((((size_t)(A) & CHUNK_ALIGN_MASK) == 0)? 0 :\ |
||
665 | ((MALLOC_ALIGNMENT - ((size_t)(A) & CHUNK_ALIGN_MASK)) & CHUNK_ALIGN_MASK)) |
||
666 | |||
3297 | Serge | 667 | /* -------------------------- MMAP preliminaries ------------------------- */ |
1616 | serge | 668 | |
3297 | Serge | 669 | /* |
670 | If HAVE_MORECORE or HAVE_MMAP are false, we just define calls and |
||
671 | checks to fail so compiler optimizer can delete code rather than |
||
672 | using so many "#if"s. |
||
673 | */ |
||
674 | |||
675 | |||
676 | /* MORECORE and MMAP must return MFAIL on failure */ |
||
1616 | serge | 677 | #define MFAIL ((void*)(MAX_SIZE_T)) |
678 | #define CMFAIL ((char*)(MFAIL)) /* defined for convenience */ |
||
679 | |||
3297 | Serge | 680 | #define should_trim(M,s) (0) |
1616 | serge | 681 | |
3297 | Serge | 682 | |
683 | |||
684 | /* --------------------------- Lock preliminaries ------------------------ */ |
||
685 | |||
1616 | serge | 686 | /* |
3297 | Serge | 687 | When locks are defined, there is one global lock, plus |
688 | one per-mspace lock. |
||
689 | |||
690 | The global lock_ensures that mparams.magic and other unique |
||
691 | mparams values are initialized only once. It also protects |
||
692 | sequences of calls to MORECORE. In many cases sys_alloc requires |
||
693 | two calls, that should not be interleaved with calls by other |
||
694 | threads. This does not protect against direct calls to MORECORE |
||
695 | by other threads not using this lock, so there is still code to |
||
696 | cope the best we can on interference. |
||
697 | |||
698 | Per-mspace locks surround calls to malloc, free, etc. |
||
699 | By default, locks are simple non-reentrant mutexes. |
||
700 | |||
701 | Because lock-protected regions generally have bounded times, it is |
||
702 | OK to use the supplied simple spinlocks. Spinlocks are likely to |
||
703 | improve performance for lightly contended applications, but worsen |
||
704 | performance under heavy contention. |
||
705 | |||
706 | If USE_LOCKS is > 1, the definitions of lock routines here are |
||
707 | bypassed, in which case you will need to define the type MLOCK_T, |
||
708 | and at least INITIAL_LOCK, DESTROY_LOCK, ACQUIRE_LOCK, RELEASE_LOCK |
||
709 | and TRY_LOCK. You must also declare a |
||
710 | static MLOCK_T malloc_global_mutex = { initialization values };. |
||
711 | |||
1616 | serge | 712 | */ |
713 | |||
3297 | Serge | 714 | static DEFINE_MUTEX(malloc_global_mutex); |
715 | |||
716 | #define ACQUIRE_MALLOC_GLOBAL_LOCK() MutexLock(&malloc_global_mutex); |
||
717 | #define RELEASE_MALLOC_GLOBAL_LOCK() MutexUnlock(&malloc_global_mutex); |
||
718 | |||
719 | |||
720 | /* ----------------------- Chunk representations ------------------------ */ |
||
721 | |||
722 | /* |
||
723 | (The following includes lightly edited explanations by Colin Plumb.) |
||
724 | |||
725 | The malloc_chunk declaration below is misleading (but accurate and |
||
726 | necessary). It declares a "view" into memory allowing access to |
||
727 | necessary fields at known offsets from a given base. |
||
728 | |||
729 | Chunks of memory are maintained using a `boundary tag' method as |
||
730 | originally described by Knuth. (See the paper by Paul Wilson |
||
731 | ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a survey of such |
||
732 | techniques.) Sizes of free chunks are stored both in the front of |
||
733 | each chunk and at the end. This makes consolidating fragmented |
||
734 | chunks into bigger chunks fast. The head fields also hold bits |
||
735 | representing whether chunks are free or in use. |
||
736 | |||
737 | Here are some pictures to make it clearer. They are "exploded" to |
||
738 | show that the state of a chunk can be thought of as extending from |
||
739 | the high 31 bits of the head field of its header through the |
||
740 | prev_foot and PINUSE_BIT bit of the following chunk header. |
||
741 | |||
742 | A chunk that's in use looks like: |
||
743 | |||
744 | chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
745 | | Size of previous chunk (if P = 0) | |
||
746 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
747 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P| |
||
748 | | Size of this chunk 1| +-+ |
||
749 | mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
750 | | | |
||
751 | +- -+ |
||
752 | | | |
||
753 | +- -+ |
||
754 | | : |
||
755 | +- size - sizeof(size_t) available payload bytes -+ |
||
756 | : | |
||
757 | chunk-> +- -+ |
||
758 | | | |
||
759 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
760 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1| |
||
761 | | Size of next chunk (may or may not be in use) | +-+ |
||
762 | mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
763 | |||
764 | And if it's free, it looks like this: |
||
765 | |||
766 | chunk-> +- -+ |
||
767 | | User payload (must be in use, or we would have merged!) | |
||
768 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
769 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P| |
||
770 | | Size of this chunk 0| +-+ |
||
771 | mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
772 | | Next pointer | |
||
773 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
774 | | Prev pointer | |
||
775 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
776 | | : |
||
777 | +- size - sizeof(struct chunk) unused bytes -+ |
||
778 | : | |
||
779 | chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
780 | | Size of this chunk | |
||
781 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
782 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| |
||
783 | | Size of next chunk (must be in use, or we would have merged)| +-+ |
||
784 | mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
785 | | : |
||
786 | +- User payload -+ |
||
787 | : | |
||
788 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
789 | |0| |
||
790 | +-+ |
||
791 | Note that since we always merge adjacent free chunks, the chunks |
||
792 | adjacent to a free chunk must be in use. |
||
793 | |||
794 | Given a pointer to a chunk (which can be derived trivially from the |
||
795 | payload pointer) we can, in O(1) time, find out whether the adjacent |
||
796 | chunks are free, and if so, unlink them from the lists that they |
||
797 | are on and merge them with the current chunk. |
||
798 | |||
799 | Chunks always begin on even word boundaries, so the mem portion |
||
800 | (which is returned to the user) is also on an even word boundary, and |
||
801 | thus at least double-word aligned. |
||
802 | |||
803 | The P (PINUSE_BIT) bit, stored in the unused low-order bit of the |
||
804 | chunk size (which is always a multiple of two words), is an in-use |
||
805 | bit for the *previous* chunk. If that bit is *clear*, then the |
||
806 | word before the current chunk size contains the previous chunk |
||
807 | size, and can be used to find the front of the previous chunk. |
||
808 | The very first chunk allocated always has this bit set, preventing |
||
809 | access to non-existent (or non-owned) memory. If pinuse is set for |
||
810 | any given chunk, then you CANNOT determine the size of the |
||
811 | previous chunk, and might even get a memory addressing fault when |
||
812 | trying to do so. |
||
813 | |||
814 | The C (CINUSE_BIT) bit, stored in the unused second-lowest bit of |
||
815 | the chunk size redundantly records whether the current chunk is |
||
816 | inuse (unless the chunk is mmapped). This redundancy enables usage |
||
817 | checks within free and realloc, and reduces indirection when freeing |
||
818 | and consolidating chunks. |
||
819 | |||
820 | Each freshly allocated chunk must have both cinuse and pinuse set. |
||
821 | That is, each allocated chunk borders either a previously allocated |
||
822 | and still in-use chunk, or the base of its memory arena. This is |
||
823 | ensured by making all allocations from the `lowest' part of any |
||
824 | found chunk. Further, no free chunk physically borders another one, |
||
825 | so each free chunk is known to be preceded and followed by either |
||
826 | inuse chunks or the ends of memory. |
||
827 | |||
828 | Note that the `foot' of the current chunk is actually represented |
||
829 | as the prev_foot of the NEXT chunk. This makes it easier to |
||
830 | deal with alignments etc but can be very confusing when trying |
||
831 | to extend or adapt this code. |
||
832 | |||
833 | The exceptions to all this are |
||
834 | |||
835 | 1. The special chunk `top' is the top-most available chunk (i.e., |
||
836 | the one bordering the end of available memory). It is treated |
||
837 | specially. Top is never included in any bin, is used only if |
||
838 | no other chunk is available, and is released back to the |
||
839 | system if it is very large (see M_TRIM_THRESHOLD). In effect, |
||
840 | the top chunk is treated as larger (and thus less well |
||
841 | fitting) than any other available chunk. The top chunk |
||
842 | doesn't update its trailing size field since there is no next |
||
843 | contiguous chunk that would have to index off it. However, |
||
844 | space is still allocated for it (TOP_FOOT_SIZE) to enable |
||
845 | separation or merging when space is extended. |
||
846 | |||
847 | 3. Chunks allocated via mmap, have both cinuse and pinuse bits |
||
848 | cleared in their head fields. Because they are allocated |
||
849 | one-by-one, each must carry its own prev_foot field, which is |
||
850 | also used to hold the offset this chunk has within its mmapped |
||
851 | region, which is needed to preserve alignment. Each mmapped |
||
852 | chunk is trailed by the first two fields of a fake next-chunk |
||
853 | for sake of usage checks. |
||
854 | |||
855 | */ |
||
856 | |||
857 | struct malloc_chunk { |
||
858 | size_t prev_foot; /* Size of previous chunk (if free). */ |
||
859 | size_t head; /* Size and inuse bits. */ |
||
860 | struct malloc_chunk* fd; /* double links -- used only if free. */ |
||
861 | struct malloc_chunk* bk; |
||
862 | }; |
||
863 | |||
864 | typedef struct malloc_chunk mchunk; |
||
865 | typedef struct malloc_chunk* mchunkptr; |
||
866 | typedef struct malloc_chunk* sbinptr; /* The type of bins of chunks */ |
||
867 | typedef unsigned int bindex_t; /* Described below */ |
||
868 | typedef unsigned int binmap_t; /* Described below */ |
||
869 | typedef unsigned int flag_t; /* The type of various bit flag sets */ |
||
870 | |||
1616 | serge | 871 | /* ------------------- Chunks sizes and alignments ----------------------- */ |
872 | |||
873 | #define MCHUNK_SIZE (sizeof(mchunk)) |
||
874 | |||
3297 | Serge | 875 | #if FOOTERS |
876 | #define CHUNK_OVERHEAD (TWO_SIZE_T_SIZES) |
||
877 | #else /* FOOTERS */ |
||
878 | #define CHUNK_OVERHEAD (SIZE_T_SIZE) |
||
879 | #endif /* FOOTERS */ |
||
880 | |||
1616 | serge | 881 | /* MMapped chunks need a second word of overhead ... */ |
882 | #define MMAP_CHUNK_OVERHEAD (TWO_SIZE_T_SIZES) |
||
883 | /* ... and additional padding for fake next-chunk at foot */ |
||
884 | #define MMAP_FOOT_PAD (FOUR_SIZE_T_SIZES) |
||
885 | |||
886 | /* The smallest size we can malloc is an aligned minimal chunk */ |
||
887 | #define MIN_CHUNK_SIZE\ |
||
888 | ((MCHUNK_SIZE + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK) |
||
889 | |||
890 | /* conversion from malloc headers to user pointers, and back */ |
||
891 | #define chunk2mem(p) ((void*)((char*)(p) + TWO_SIZE_T_SIZES)) |
||
892 | #define mem2chunk(mem) ((mchunkptr)((char*)(mem) - TWO_SIZE_T_SIZES)) |
||
893 | /* chunk associated with aligned address A */ |
||
894 | #define align_as_chunk(A) (mchunkptr)((A) + align_offset(chunk2mem(A))) |
||
895 | |||
896 | /* Bounds on request (not chunk) sizes. */ |
||
897 | #define MAX_REQUEST ((-MIN_CHUNK_SIZE) << 2) |
||
898 | #define MIN_REQUEST (MIN_CHUNK_SIZE - CHUNK_OVERHEAD - SIZE_T_ONE) |
||
899 | |||
900 | /* pad request bytes into a usable size */ |
||
901 | #define pad_request(req) \ |
||
902 | (((req) + CHUNK_OVERHEAD + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK) |
||
903 | |||
904 | /* pad request, checking for minimum (but not maximum) */ |
||
905 | #define request2size(req) \ |
||
906 | (((req) < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(req)) |
||
907 | |||
3297 | Serge | 908 | |
1616 | serge | 909 | /* ------------------ Operations on head and foot fields ----------------- */ |
910 | |||
911 | /* |
||
912 | The head field of a chunk is or'ed with PINUSE_BIT when previous |
||
913 | adjacent chunk in use, and or'ed with CINUSE_BIT if this chunk is in |
||
914 | use, unless mmapped, in which case both bits are cleared. |
||
915 | |||
916 | FLAG4_BIT is not used by this malloc, but might be useful in extensions. |
||
917 | */ |
||
918 | |||
919 | #define PINUSE_BIT (SIZE_T_ONE) |
||
920 | #define CINUSE_BIT (SIZE_T_TWO) |
||
921 | #define FLAG4_BIT (SIZE_T_FOUR) |
||
922 | #define INUSE_BITS (PINUSE_BIT|CINUSE_BIT) |
||
923 | #define FLAG_BITS (PINUSE_BIT|CINUSE_BIT|FLAG4_BIT) |
||
924 | |||
925 | /* Head value for fenceposts */ |
||
926 | #define FENCEPOST_HEAD (INUSE_BITS|SIZE_T_SIZE) |
||
927 | |||
928 | /* extraction of fields from head words */ |
||
929 | #define cinuse(p) ((p)->head & CINUSE_BIT) |
||
930 | #define pinuse(p) ((p)->head & PINUSE_BIT) |
||
3297 | Serge | 931 | #define flag4inuse(p) ((p)->head & FLAG4_BIT) |
1616 | serge | 932 | #define is_inuse(p) (((p)->head & INUSE_BITS) != PINUSE_BIT) |
933 | #define is_mmapped(p) (((p)->head & INUSE_BITS) == 0) |
||
934 | |||
935 | #define chunksize(p) ((p)->head & ~(FLAG_BITS)) |
||
936 | |||
937 | #define clear_pinuse(p) ((p)->head &= ~PINUSE_BIT) |
||
3297 | Serge | 938 | #define set_flag4(p) ((p)->head |= FLAG4_BIT) |
939 | #define clear_flag4(p) ((p)->head &= ~FLAG4_BIT) |
||
1616 | serge | 940 | |
941 | /* Treat space at ptr +/- offset as a chunk */ |
||
942 | #define chunk_plus_offset(p, s) ((mchunkptr)(((char*)(p)) + (s))) |
||
943 | #define chunk_minus_offset(p, s) ((mchunkptr)(((char*)(p)) - (s))) |
||
944 | |||
945 | /* Ptr to next or previous physical malloc_chunk. */ |
||
946 | #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->head & ~FLAG_BITS))) |
||
947 | #define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_foot) )) |
||
948 | |||
949 | /* extract next chunk's pinuse bit */ |
||
950 | #define next_pinuse(p) ((next_chunk(p)->head) & PINUSE_BIT) |
||
951 | |||
3297 | Serge | 952 | /* Get/set size at footer */ |
953 | #define get_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_foot) |
||
954 | #define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_foot = (s)) |
||
955 | |||
1616 | serge | 956 | /* Set size, pinuse bit, and foot */ |
957 | #define set_size_and_pinuse_of_free_chunk(p, s)\ |
||
958 | ((p)->head = (s|PINUSE_BIT), set_foot(p, s)) |
||
959 | |||
960 | /* Set size, pinuse bit, foot, and clear next pinuse */ |
||
961 | #define set_free_with_pinuse(p, s, n)\ |
||
962 | (clear_pinuse(n), set_size_and_pinuse_of_free_chunk(p, s)) |
||
963 | |||
964 | /* Get the internal overhead associated with chunk p */ |
||
965 | #define overhead_for(p)\ |
||
966 | (is_mmapped(p)? MMAP_CHUNK_OVERHEAD : CHUNK_OVERHEAD) |
||
967 | |||
3297 | Serge | 968 | /* Return true if malloced space is not necessarily cleared */ |
969 | #if MMAP_CLEARS |
||
970 | #define calloc_must_clear(p) (!is_mmapped(p)) |
||
971 | #else /* MMAP_CLEARS */ |
||
972 | #define calloc_must_clear(p) (1) |
||
973 | #endif /* MMAP_CLEARS */ |
||
1616 | serge | 974 | |
3297 | Serge | 975 | /* ---------------------- Overlaid data structures ----------------------- */ |
976 | |||
977 | /* |
||
978 | When chunks are not in use, they are treated as nodes of either |
||
979 | lists or trees. |
||
980 | |||
981 | "Small" chunks are stored in circular doubly-linked lists, and look |
||
982 | like this: |
||
983 | |||
984 | chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
985 | | Size of previous chunk | |
||
986 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
987 | `head:' | Size of chunk, in bytes |P| |
||
988 | mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
989 | | Forward pointer to next chunk in list | |
||
990 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
991 | | Back pointer to previous chunk in list | |
||
992 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
993 | | Unused space (may be 0 bytes long) . |
||
994 | . . |
||
995 | . | |
||
996 | nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
997 | `foot:' | Size of chunk, in bytes | |
||
998 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
999 | |||
1000 | Larger chunks are kept in a form of bitwise digital trees (aka |
||
1001 | tries) keyed on chunksizes. Because malloc_tree_chunks are only for |
||
1002 | free chunks greater than 256 bytes, their size doesn't impose any |
||
1003 | constraints on user chunk sizes. Each node looks like: |
||
1004 | |||
1005 | chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
1006 | | Size of previous chunk | |
||
1007 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
1008 | `head:' | Size of chunk, in bytes |P| |
||
1009 | mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
1010 | | Forward pointer to next chunk of same size | |
||
1011 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
1012 | | Back pointer to previous chunk of same size | |
||
1013 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
1014 | | Pointer to left child (child[0]) | |
||
1015 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
1016 | | Pointer to right child (child[1]) | |
||
1017 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
1018 | | Pointer to parent | |
||
1019 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
1020 | | bin index of this chunk | |
||
1021 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
1022 | | Unused space . |
||
1023 | . | |
||
1024 | nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
1025 | `foot:' | Size of chunk, in bytes | |
||
1026 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
||
1027 | |||
1028 | Each tree holding treenodes is a tree of unique chunk sizes. Chunks |
||
1029 | of the same size are arranged in a circularly-linked list, with only |
||
1030 | the oldest chunk (the next to be used, in our FIFO ordering) |
||
1031 | actually in the tree. (Tree members are distinguished by a non-null |
||
1032 | parent pointer.) If a chunk with the same size an an existing node |
||
1033 | is inserted, it is linked off the existing node using pointers that |
||
1034 | work in the same way as fd/bk pointers of small chunks. |
||
1035 | |||
1036 | Each tree contains a power of 2 sized range of chunk sizes (the |
||
1037 | smallest is 0x100 <= x < 0x180), which is is divided in half at each |
||
1038 | tree level, with the chunks in the smaller half of the range (0x100 |
||
1039 | <= x < 0x140 for the top nose) in the left subtree and the larger |
||
1040 | half (0x140 <= x < 0x180) in the right subtree. This is, of course, |
||
1041 | done by inspecting individual bits. |
||
1042 | |||
1043 | Using these rules, each node's left subtree contains all smaller |
||
1044 | sizes than its right subtree. However, the node at the root of each |
||
1045 | subtree has no particular ordering relationship to either. (The |
||
1046 | dividing line between the subtree sizes is based on trie relation.) |
||
1047 | If we remove the last chunk of a given size from the interior of the |
||
1048 | tree, we need to replace it with a leaf node. The tree ordering |
||
1049 | rules permit a node to be replaced by any leaf below it. |
||
1050 | |||
1051 | The smallest chunk in a tree (a common operation in a best-fit |
||
1052 | allocator) can be found by walking a path to the leftmost leaf in |
||
1053 | the tree. Unlike a usual binary tree, where we follow left child |
||
1054 | pointers until we reach a null, here we follow the right child |
||
1055 | pointer any time the left one is null, until we reach a leaf with |
||
1056 | both child pointers null. The smallest chunk in the tree will be |
||
1057 | somewhere along that path. |
||
1058 | |||
1059 | The worst case number of steps to add, find, or remove a node is |
||
1060 | bounded by the number of bits differentiating chunks within |
||
1061 | bins. Under current bin calculations, this ranges from 6 up to 21 |
||
1062 | (for 32 bit sizes) or up to 53 (for 64 bit sizes). The typical case |
||
1063 | is of course much better. |
||
1064 | */ |
||
1065 | |||
1616 | serge | 1066 | struct malloc_tree_chunk { |
1067 | /* The first four fields must be compatible with malloc_chunk */ |
||
1068 | size_t prev_foot; |
||
1069 | size_t head; |
||
1070 | struct malloc_tree_chunk* fd; |
||
1071 | struct malloc_tree_chunk* bk; |
||
1072 | |||
1073 | struct malloc_tree_chunk* child[2]; |
||
1074 | struct malloc_tree_chunk* parent; |
||
1075 | bindex_t index; |
||
1076 | }; |
||
1077 | |||
1078 | typedef struct malloc_tree_chunk tchunk; |
||
1079 | typedef struct malloc_tree_chunk* tchunkptr; |
||
1080 | typedef struct malloc_tree_chunk* tbinptr; /* The type of bins of trees */ |
||
1081 | |||
1082 | /* A little helper macro for trees */ |
||
1083 | #define leftmost_child(t) ((t)->child[0] != 0? (t)->child[0] : (t)->child[1]) |
||
1084 | |||
3297 | Serge | 1085 | /* ----------------------------- Segments -------------------------------- */ |
1616 | serge | 1086 | |
3297 | Serge | 1087 | /* |
1088 | Each malloc space may include non-contiguous segments, held in a |
||
1089 | list headed by an embedded malloc_segment record representing the |
||
1090 | top-most space. Segments also include flags holding properties of |
||
1091 | the space. Large chunks that are directly allocated by mmap are not |
||
1092 | included in this list. They are instead independently created and |
||
1093 | destroyed without otherwise keeping track of them. |
||
1094 | |||
1095 | Segment management mainly comes into play for spaces allocated by |
||
1096 | MMAP. Any call to MMAP might or might not return memory that is |
||
1097 | adjacent to an existing segment. MORECORE normally contiguously |
||
1098 | extends the current space, so this space is almost always adjacent, |
||
1099 | which is simpler and faster to deal with. (This is why MORECORE is |
||
1100 | used preferentially to MMAP when both are available -- see |
||
1101 | sys_alloc.) When allocating using MMAP, we don't use any of the |
||
1102 | hinting mechanisms (inconsistently) supported in various |
||
1103 | implementations of unix mmap, or distinguish reserving from |
||
1104 | committing memory. Instead, we just ask for space, and exploit |
||
1105 | contiguity when we get it. It is probably possible to do |
||
1106 | better than this on some systems, but no general scheme seems |
||
1107 | to be significantly better. |
||
1108 | |||
1109 | Management entails a simpler variant of the consolidation scheme |
||
1110 | used for chunks to reduce fragmentation -- new adjacent memory is |
||
1111 | normally prepended or appended to an existing segment. However, |
||
1112 | there are limitations compared to chunk consolidation that mostly |
||
1113 | reflect the fact that segment processing is relatively infrequent |
||
1114 | (occurring only when getting memory from system) and that we |
||
1115 | don't expect to have huge numbers of segments: |
||
1116 | |||
1117 | * Segments are not indexed, so traversal requires linear scans. (It |
||
1118 | would be possible to index these, but is not worth the extra |
||
1119 | overhead and complexity for most programs on most platforms.) |
||
1120 | * New segments are only appended to old ones when holding top-most |
||
1121 | memory; if they cannot be prepended to others, they are held in |
||
1122 | different segments. |
||
1123 | |||
1124 | Except for the top-most segment of an mstate, each segment record |
||
1125 | is kept at the tail of its segment. Segments are added by pushing |
||
1126 | segment records onto the list headed by &mstate.seg for the |
||
1127 | containing mstate. |
||
1128 | |||
1129 | Segment flags control allocation/merge/deallocation policies: |
||
1130 | * If EXTERN_BIT set, then we did not allocate this segment, |
||
1131 | and so should not try to deallocate or merge with others. |
||
1132 | (This currently holds only for the initial segment passed |
||
1133 | into create_mspace_with_base.) |
||
1134 | * If USE_MMAP_BIT set, the segment may be merged with |
||
1135 | other surrounding mmapped segments and trimmed/de-allocated |
||
1136 | using munmap. |
||
1137 | * If neither bit is set, then the segment was obtained using |
||
1138 | MORECORE so can be merged with surrounding MORECORE'd segments |
||
1139 | and deallocated/trimmed using MORECORE with negative arguments. |
||
1140 | */ |
||
1141 | |||
1616 | serge | 1142 | struct malloc_segment { |
1143 | char* base; /* base address */ |
||
1144 | size_t size; /* allocated size */ |
||
1145 | struct malloc_segment* next; /* ptr to next segment */ |
||
1146 | flag_t sflags; /* mmap and extern flag */ |
||
1147 | }; |
||
1148 | |||
1149 | #define is_mmapped_segment(S) ((S)->sflags & USE_MMAP_BIT) |
||
1150 | #define is_extern_segment(S) ((S)->sflags & EXTERN_BIT) |
||
1151 | |||
1152 | typedef struct malloc_segment msegment; |
||
1153 | typedef struct malloc_segment* msegmentptr; |
||
1154 | |||
1155 | /* ---------------------------- malloc_state ----------------------------- */ |
||
1156 | |||
1157 | /* |
||
1158 | A malloc_state holds all of the bookkeeping for a space. |
||
1159 | The main fields are: |
||
1160 | |||
1161 | Top |
||
1162 | The topmost chunk of the currently active segment. Its size is |
||
1163 | cached in topsize. The actual size of topmost space is |
||
1164 | topsize+TOP_FOOT_SIZE, which includes space reserved for adding |
||
1165 | fenceposts and segment records if necessary when getting more |
||
1166 | space from the system. The size at which to autotrim top is |
||
1167 | cached from mparams in trim_check, except that it is disabled if |
||
1168 | an autotrim fails. |
||
1169 | |||
1170 | Designated victim (dv) |
||
1171 | This is the preferred chunk for servicing small requests that |
||
1172 | don't have exact fits. It is normally the chunk split off most |
||
1173 | recently to service another small request. Its size is cached in |
||
1174 | dvsize. The link fields of this chunk are not maintained since it |
||
1175 | is not kept in a bin. |
||
1176 | |||
1177 | SmallBins |
||
1178 | An array of bin headers for free chunks. These bins hold chunks |
||
1179 | with sizes less than MIN_LARGE_SIZE bytes. Each bin contains |
||
1180 | chunks of all the same size, spaced 8 bytes apart. To simplify |
||
1181 | use in double-linked lists, each bin header acts as a malloc_chunk |
||
1182 | pointing to the real first node, if it exists (else pointing to |
||
1183 | itself). This avoids special-casing for headers. But to avoid |
||
1184 | waste, we allocate only the fd/bk pointers of bins, and then use |
||
1185 | repositioning tricks to treat these as the fields of a chunk. |
||
1186 | |||
1187 | TreeBins |
||
1188 | Treebins are pointers to the roots of trees holding a range of |
||
1189 | sizes. There are 2 equally spaced treebins for each power of two |
||
1190 | from TREE_SHIFT to TREE_SHIFT+16. The last bin holds anything |
||
1191 | larger. |
||
1192 | |||
1193 | Bin maps |
||
1194 | There is one bit map for small bins ("smallmap") and one for |
||
1195 | treebins ("treemap). Each bin sets its bit when non-empty, and |
||
1196 | clears the bit when empty. Bit operations are then used to avoid |
||
1197 | bin-by-bin searching -- nearly all "search" is done without ever |
||
1198 | looking at bins that won't be selected. The bit maps |
||
1199 | conservatively use 32 bits per map word, even if on 64bit system. |
||
1200 | For a good description of some of the bit-based techniques used |
||
1201 | here, see Henry S. Warren Jr's book "Hacker's Delight" (and |
||
1202 | supplement at http://hackersdelight.org/). Many of these are |
||
1203 | intended to reduce the branchiness of paths through malloc etc, as |
||
1204 | well as to reduce the number of memory locations read or written. |
||
1205 | |||
1206 | Segments |
||
1207 | A list of segments headed by an embedded malloc_segment record |
||
1208 | representing the initial space. |
||
1209 | |||
1210 | Address check support |
||
1211 | The least_addr field is the least address ever obtained from |
||
1212 | MORECORE or MMAP. Attempted frees and reallocs of any address less |
||
1213 | than this are trapped (unless INSECURE is defined). |
||
1214 | |||
1215 | Magic tag |
||
1216 | A cross-check field that should always hold same value as mparams.magic. |
||
1217 | |||
3297 | Serge | 1218 | Max allowed footprint |
1219 | The maximum allowed bytes to allocate from system (zero means no limit) |
||
1220 | |||
1616 | serge | 1221 | Flags |
1222 | Bits recording whether to use MMAP, locks, or contiguous MORECORE |
||
1223 | |||
1224 | Statistics |
||
1225 | Each space keeps track of current and maximum system memory |
||
1226 | obtained via MORECORE or MMAP. |
||
1227 | |||
1228 | Trim support |
||
1229 | Fields holding the amount of unused topmost memory that should trigger |
||
3297 | Serge | 1230 | trimming, and a counter to force periodic scanning to release unused |
1616 | serge | 1231 | non-topmost segments. |
1232 | |||
1233 | Locking |
||
1234 | If USE_LOCKS is defined, the "mutex" lock is acquired and released |
||
1235 | around every public call using this mspace. |
||
1236 | |||
1237 | Extension support |
||
1238 | A void* pointer and a size_t field that can be used to help implement |
||
1239 | extensions to this malloc. |
||
1240 | */ |
||
1241 | |||
1242 | /* Bin types, widths and sizes */ |
||
1243 | #define NSMALLBINS (32U) |
||
1244 | #define NTREEBINS (32U) |
||
1245 | #define SMALLBIN_SHIFT (3U) |
||
1246 | #define SMALLBIN_WIDTH (SIZE_T_ONE << SMALLBIN_SHIFT) |
||
1247 | #define TREEBIN_SHIFT (8U) |
||
1248 | #define MIN_LARGE_SIZE (SIZE_T_ONE << TREEBIN_SHIFT) |
||
1249 | #define MAX_SMALL_SIZE (MIN_LARGE_SIZE - SIZE_T_ONE) |
||
1250 | #define MAX_SMALL_REQUEST (MAX_SMALL_SIZE - CHUNK_ALIGN_MASK - CHUNK_OVERHEAD) |
||
1251 | |||
1252 | struct malloc_state { |
||
1253 | binmap_t smallmap; |
||
1254 | binmap_t treemap; |
||
1255 | size_t dvsize; |
||
1256 | size_t topsize; |
||
1257 | char* least_addr; |
||
1258 | mchunkptr dv; |
||
1259 | mchunkptr top; |
||
1260 | size_t trim_check; |
||
1261 | size_t release_checks; |
||
1262 | size_t magic; |
||
1263 | mchunkptr smallbins[(NSMALLBINS+1)*2]; |
||
1264 | tbinptr treebins[NTREEBINS]; |
||
1265 | size_t footprint; |
||
1266 | size_t max_footprint; |
||
3297 | Serge | 1267 | size_t footprint_limit; /* zero means no limit */ |
1616 | serge | 1268 | flag_t mflags; |
1269 | struct mutex lock; /* locate lock among fields that rarely change */ |
||
1270 | msegment seg; |
||
1271 | void* extp; /* Unused but available for extensions */ |
||
1272 | size_t exts; |
||
1273 | }; |
||
1274 | |||
1275 | typedef struct malloc_state* mstate; |
||
1276 | |||
1277 | /* ------------- Global malloc_state and malloc_params ------------------- */ |
||
1278 | |||
1279 | /* |
||
1280 | malloc_params holds global properties, including those that can be |
||
1281 | dynamically set using mallopt. There is a single instance, mparams, |
||
1282 | initialized in init_mparams. Note that the non-zeroness of "magic" |
||
1283 | also serves as an initialization flag. |
||
1284 | */ |
||
1285 | |||
3297 | Serge | 1286 | struct malloc_params { |
1287 | size_t magic; |
||
1616 | serge | 1288 | size_t page_size; |
1289 | size_t granularity; |
||
1290 | size_t mmap_threshold; |
||
1291 | size_t trim_threshold; |
||
1292 | flag_t default_mflags; |
||
1293 | }; |
||
1294 | |||
1295 | static struct malloc_params mparams; |
||
1296 | |||
3297 | Serge | 1297 | /* Ensure mparams initialized */ |
1616 | serge | 1298 | #define ensure_initialization() (void)(mparams.magic != 0 || init_mparams()) |
1299 | |||
1300 | static struct malloc_state _gm_; |
||
1301 | #define gm (&_gm_) |
||
1302 | #define is_global(M) ((M) == &_gm_) |
||
1303 | |||
1304 | #define is_initialized(M) ((M)->top != 0) |
||
1305 | |||
3297 | Serge | 1306 | /* -------------------------- system alloc setup ------------------------- */ |
1616 | serge | 1307 | |
3297 | Serge | 1308 | /* Operations on mflags */ |
1616 | serge | 1309 | |
3297 | Serge | 1310 | #define use_lock(M) ((M)->mflags & USE_LOCK_BIT) |
1311 | #define enable_lock(M) ((M)->mflags |= USE_LOCK_BIT) |
||
1312 | #if USE_LOCKS |
||
1313 | #define disable_lock(M) ((M)->mflags &= ~USE_LOCK_BIT) |
||
1314 | #else |
||
1315 | #define disable_lock(M) |
||
1316 | #endif |
||
1616 | serge | 1317 | |
3297 | Serge | 1318 | #define use_mmap(M) ((M)->mflags & USE_MMAP_BIT) |
1319 | #define enable_mmap(M) ((M)->mflags |= USE_MMAP_BIT) |
||
1320 | #if HAVE_MMAP |
||
1321 | #define disable_mmap(M) ((M)->mflags &= ~USE_MMAP_BIT) |
||
1322 | #else |
||
1323 | #define disable_mmap(M) |
||
1324 | #endif |
||
1616 | serge | 1325 | |
3297 | Serge | 1326 | #define use_noncontiguous(M) ((M)->mflags & USE_NONCONTIGUOUS_BIT) |
1327 | #define disable_contiguous(M) ((M)->mflags |= USE_NONCONTIGUOUS_BIT) |
||
1328 | |||
1329 | #define set_lock(M,L)\ |
||
1330 | ((M)->mflags = (L)?\ |
||
1331 | ((M)->mflags | USE_LOCK_BIT) :\ |
||
1332 | ((M)->mflags & ~USE_LOCK_BIT)) |
||
1333 | |||
1334 | /* page-align a size */ |
||
1335 | #define page_align(S)\ |
||
1336 | (((S) + (mparams.page_size - SIZE_T_ONE)) & ~(mparams.page_size - SIZE_T_ONE)) |
||
1337 | |||
1338 | /* granularity-align a size */ |
||
1339 | #define granularity_align(S)\ |
||
1340 | (((S) + (mparams.granularity - SIZE_T_ONE))\ |
||
1341 | & ~(mparams.granularity - SIZE_T_ONE)) |
||
1342 | |||
1343 | |||
1344 | /* For mmap, use granularity alignment on windows, else page-align */ |
||
1345 | #ifdef WIN32 |
||
1346 | #define mmap_align(S) granularity_align(S) |
||
1347 | #else |
||
1348 | #define mmap_align(S) page_align(S) |
||
1349 | #endif |
||
1350 | |||
1351 | /* For sys_alloc, enough padding to ensure can malloc request on success */ |
||
1352 | #define SYS_ALLOC_PADDING (TOP_FOOT_SIZE + MALLOC_ALIGNMENT) |
||
1353 | |||
1354 | #define is_page_aligned(S)\ |
||
1355 | (((size_t)(S) & (mparams.page_size - SIZE_T_ONE)) == 0) |
||
1356 | #define is_granularity_aligned(S)\ |
||
1357 | (((size_t)(S) & (mparams.granularity - SIZE_T_ONE)) == 0) |
||
1358 | |||
1359 | /* True if segment S holds address A */ |
||
1360 | #define segment_holds(S, A)\ |
||
1361 | ((char*)(A) >= S->base && (char*)(A) < S->base + S->size) |
||
1362 | |||
1363 | /* Return segment holding given address */ |
||
1364 | static msegmentptr segment_holding(mstate m, char* addr) { |
||
1365 | msegmentptr sp = &m->seg; |
||
1366 | for (;;) { |
||
1367 | if (addr >= sp->base && addr < sp->base + sp->size) |
||
1368 | return sp; |
||
1369 | if ((sp = sp->next) == 0) |
||
1370 | return 0; |
||
1371 | } |
||
1372 | } |
||
1373 | |||
1374 | /* Return true if segment contains a segment link */ |
||
1375 | static int has_segment_link(mstate m, msegmentptr ss) { |
||
1376 | msegmentptr sp = &m->seg; |
||
1377 | for (;;) { |
||
1378 | if ((char*)sp >= ss->base && (char*)sp < ss->base + ss->size) |
||
1379 | return 1; |
||
1380 | if ((sp = sp->next) == 0) |
||
1381 | return 0; |
||
1382 | } |
||
1383 | } |
||
1384 | |||
1385 | |||
1386 | /* |
||
1387 | TOP_FOOT_SIZE is padding at the end of a segment, including space |
||
1388 | that may be needed to place segment records and fenceposts when new |
||
1389 | noncontiguous segments are added. |
||
1390 | */ |
||
1391 | #define TOP_FOOT_SIZE\ |
||
1392 | (align_offset(chunk2mem(0))+pad_request(sizeof(struct malloc_segment))+MIN_CHUNK_SIZE) |
||
1393 | |||
1394 | |||
1395 | /* ------------------------------- Hooks -------------------------------- */ |
||
1396 | |||
1397 | /* |
||
1398 | PREACTION should be defined to return 0 on success, and nonzero on |
||
1399 | failure. If you are not using locking, you can redefine these to do |
||
1400 | anything you like. |
||
1401 | */ |
||
1402 | |||
1616 | serge | 1403 | #define PREACTION(M) ( MutexLock(&(M)->lock)) |
1404 | #define POSTACTION(M) { MutexUnlock(&(M)->lock); } |
||
1405 | |||
3297 | Serge | 1406 | /* -------------------------- Debugging setup ---------------------------- */ |
1616 | serge | 1407 | |
3297 | Serge | 1408 | #if ! DEBUG |
1409 | |||
1410 | #define check_free_chunk(M,P) |
||
1411 | #define check_inuse_chunk(M,P) |
||
1412 | #define check_malloced_chunk(M,P,N) |
||
1413 | #define check_mmapped_chunk(M,P) |
||
1414 | #define check_malloc_state(M) |
||
1415 | #define check_top_chunk(M,P) |
||
1416 | |||
1417 | #else /* DEBUG */ |
||
1418 | #define check_free_chunk(M,P) do_check_free_chunk(M,P) |
||
1419 | #define check_inuse_chunk(M,P) do_check_inuse_chunk(M,P) |
||
1420 | #define check_top_chunk(M,P) do_check_top_chunk(M,P) |
||
1421 | #define check_malloced_chunk(M,P,N) do_check_malloced_chunk(M,P,N) |
||
1422 | #define check_mmapped_chunk(M,P) do_check_mmapped_chunk(M,P) |
||
1423 | #define check_malloc_state(M) do_check_malloc_state(M) |
||
1424 | |||
1425 | static void do_check_any_chunk(mstate m, mchunkptr p); |
||
1426 | static void do_check_top_chunk(mstate m, mchunkptr p); |
||
1427 | static void do_check_mmapped_chunk(mstate m, mchunkptr p); |
||
1428 | static void do_check_inuse_chunk(mstate m, mchunkptr p); |
||
1429 | static void do_check_free_chunk(mstate m, mchunkptr p); |
||
1430 | static void do_check_malloced_chunk(mstate m, void* mem, size_t s); |
||
1431 | static void do_check_tree(mstate m, tchunkptr t); |
||
1432 | static void do_check_treebin(mstate m, bindex_t i); |
||
1433 | static void do_check_smallbin(mstate m, bindex_t i); |
||
1434 | static void do_check_malloc_state(mstate m); |
||
1435 | static int bin_find(mstate m, mchunkptr x); |
||
1436 | static size_t traverse_and_check(mstate m); |
||
1437 | #endif /* DEBUG */ |
||
1438 | |||
1616 | serge | 1439 | /* ---------------------------- Indexing Bins ---------------------------- */ |
1440 | |||
1441 | #define is_small(s) (((s) >> SMALLBIN_SHIFT) < NSMALLBINS) |
||
3297 | Serge | 1442 | #define small_index(s) (bindex_t)((s) >> SMALLBIN_SHIFT) |
1616 | serge | 1443 | #define small_index2size(i) ((i) << SMALLBIN_SHIFT) |
1444 | #define MIN_SMALL_INDEX (small_index(MIN_CHUNK_SIZE)) |
||
1445 | |||
1446 | /* addressing by index. See above about smallbin repositioning */ |
||
1447 | #define smallbin_at(M, i) ((sbinptr)((char*)&((M)->smallbins[(i)<<1]))) |
||
1448 | #define treebin_at(M,i) (&((M)->treebins[i])) |
||
1449 | |||
1450 | #define compute_tree_index(S, I)\ |
||
1451 | {\ |
||
1452 | unsigned int X = S >> TREEBIN_SHIFT;\ |
||
1453 | if (X == 0)\ |
||
1454 | I = 0;\ |
||
1455 | else if (X > 0xFFFF)\ |
||
1456 | I = NTREEBINS-1;\ |
||
1457 | else {\ |
||
3297 | Serge | 1458 | unsigned int K = (unsigned) sizeof(X)*__CHAR_BIT__ - 1 - (unsigned) __builtin_clz(X); \ |
1616 | serge | 1459 | I = (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\ |
1460 | }\ |
||
1461 | } |
||
1462 | |||
3297 | Serge | 1463 | |
1464 | |||
1616 | serge | 1465 | /* Bit representing maximum resolved size in a treebin at i */ |
1466 | #define bit_for_tree_index(i) \ |
||
1467 | (i == NTREEBINS-1)? (SIZE_T_BITSIZE-1) : (((i) >> 1) + TREEBIN_SHIFT - 2) |
||
1468 | |||
1469 | /* Shift placing maximum resolved bit in a treebin at i as sign bit */ |
||
1470 | #define leftshift_for_tree_index(i) \ |
||
1471 | ((i == NTREEBINS-1)? 0 : \ |
||
1472 | ((SIZE_T_BITSIZE-SIZE_T_ONE) - (((i) >> 1) + TREEBIN_SHIFT - 2))) |
||
1473 | |||
1474 | /* The size of the smallest chunk held in bin with index i */ |
||
1475 | #define minsize_for_tree_index(i) \ |
||
1476 | ((SIZE_T_ONE << (((i) >> 1) + TREEBIN_SHIFT)) | \ |
||
1477 | (((size_t)((i) & SIZE_T_ONE)) << (((i) >> 1) + TREEBIN_SHIFT - 1))) |
||
1478 | |||
1479 | |||
1480 | /* ------------------------ Operations on bin maps ----------------------- */ |
||
1481 | |||
1482 | /* bit corresponding to given index */ |
||
1483 | #define idx2bit(i) ((binmap_t)(1) << (i)) |
||
1484 | |||
1485 | /* Mark/Clear bits with given index */ |
||
1486 | #define mark_smallmap(M,i) ((M)->smallmap |= idx2bit(i)) |
||
1487 | #define clear_smallmap(M,i) ((M)->smallmap &= ~idx2bit(i)) |
||
1488 | #define smallmap_is_marked(M,i) ((M)->smallmap & idx2bit(i)) |
||
1489 | |||
1490 | #define mark_treemap(M,i) ((M)->treemap |= idx2bit(i)) |
||
1491 | #define clear_treemap(M,i) ((M)->treemap &= ~idx2bit(i)) |
||
1492 | #define treemap_is_marked(M,i) ((M)->treemap & idx2bit(i)) |
||
1493 | |||
1494 | /* isolate the least set bit of a bitmap */ |
||
1495 | #define least_bit(x) ((x) & -(x)) |
||
1496 | |||
1497 | /* mask with all bits to left of least bit of x on */ |
||
1498 | #define left_bits(x) ((x<<1) | -(x<<1)) |
||
1499 | |||
1500 | /* mask with all bits to left of or equal to least bit of x on */ |
||
1501 | #define same_or_left_bits(x) ((x) | -(x)) |
||
1502 | |||
1503 | #define compute_bit2idx(X, I)\ |
||
1504 | {\ |
||
1505 | unsigned int J;\ |
||
3297 | Serge | 1506 | J = __builtin_ctz(X); \ |
1616 | serge | 1507 | I = (bindex_t)J;\ |
1508 | } |
||
1509 | |||
3297 | Serge | 1510 | /* ----------------------- Runtime Check Support ------------------------- */ |
1616 | serge | 1511 | |
3297 | Serge | 1512 | /* |
1513 | For security, the main invariant is that malloc/free/etc never |
||
1514 | writes to a static address other than malloc_state, unless static |
||
1515 | malloc_state itself has been corrupted, which cannot occur via |
||
1516 | malloc (because of these checks). In essence this means that we |
||
1517 | believe all pointers, sizes, maps etc held in malloc_state, but |
||
1518 | check all of those linked or offsetted from other embedded data |
||
1519 | structures. These checks are interspersed with main code in a way |
||
1520 | that tends to minimize their run-time cost. |
||
1521 | |||
1522 | When FOOTERS is defined, in addition to range checking, we also |
||
1523 | verify footer fields of inuse chunks, which can be used guarantee |
||
1524 | that the mstate controlling malloc/free is intact. This is a |
||
1525 | streamlined version of the approach described by William Robertson |
||
1526 | et al in "Run-time Detection of Heap-based Overflows" LISA'03 |
||
1527 | http://www.usenix.org/events/lisa03/tech/robertson.html The footer |
||
1528 | of an inuse chunk holds the xor of its mstate and a random seed, |
||
1529 | that is checked upon calls to free() and realloc(). This is |
||
1530 | (probabalistically) unguessable from outside the program, but can be |
||
1531 | computed by any code successfully malloc'ing any chunk, so does not |
||
1532 | itself provide protection against code that has already broken |
||
1533 | security through some other means. Unlike Robertson et al, we |
||
1534 | always dynamically check addresses of all offset chunks (previous, |
||
1535 | next, etc). This turns out to be cheaper than relying on hashes. |
||
1536 | */ |
||
1537 | |||
1538 | #if !INSECURE |
||
1539 | /* Check if address a is at least as high as any from MORECORE or MMAP */ |
||
1540 | #define ok_address(M, a) ((char*)(a) >= (M)->least_addr) |
||
1541 | /* Check if address of next chunk n is higher than base chunk p */ |
||
1542 | #define ok_next(p, n) ((char*)(p) < (char*)(n)) |
||
1543 | /* Check if p has inuse status */ |
||
1544 | #define ok_inuse(p) is_inuse(p) |
||
1545 | /* Check if p has its pinuse bit on */ |
||
1546 | #define ok_pinuse(p) pinuse(p) |
||
1547 | |||
1548 | #else /* !INSECURE */ |
||
1549 | #define ok_address(M, a) (1) |
||
1550 | #define ok_next(b, n) (1) |
||
1551 | #define ok_inuse(p) (1) |
||
1552 | #define ok_pinuse(p) (1) |
||
1553 | #endif /* !INSECURE */ |
||
1554 | |||
1555 | #if (FOOTERS && !INSECURE) |
||
1556 | /* Check if (alleged) mstate m has expected magic field */ |
||
1557 | #define ok_magic(M) ((M)->magic == mparams.magic) |
||
1558 | #else /* (FOOTERS && !INSECURE) */ |
||
1559 | #define ok_magic(M) (1) |
||
1560 | #endif /* (FOOTERS && !INSECURE) */ |
||
1561 | |||
1562 | /* In gcc, use __builtin_expect to minimize impact of checks */ |
||
1563 | #if !INSECURE |
||
1564 | #if defined(__GNUC__) && __GNUC__ >= 3 |
||
1565 | #define RTCHECK(e) __builtin_expect(e, 1) |
||
1566 | #else /* GNUC */ |
||
1567 | #define RTCHECK(e) (e) |
||
1568 | #endif /* GNUC */ |
||
1569 | #else /* !INSECURE */ |
||
1570 | #define RTCHECK(e) (1) |
||
1571 | #endif /* !INSECURE */ |
||
1572 | |||
1573 | /* macros to set up inuse chunks with or without footers */ |
||
1574 | |||
1575 | #if !FOOTERS |
||
1576 | |||
1616 | serge | 1577 | #define mark_inuse_foot(M,p,s) |
1578 | |||
1579 | /* Macros for setting head/foot of non-mmapped chunks */ |
||
1580 | |||
1581 | /* Set cinuse bit and pinuse bit of next chunk */ |
||
1582 | #define set_inuse(M,p,s)\ |
||
1583 | ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\ |
||
1584 | ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT) |
||
1585 | |||
1586 | /* Set cinuse and pinuse of this chunk and pinuse of next chunk */ |
||
1587 | #define set_inuse_and_pinuse(M,p,s)\ |
||
1588 | ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\ |
||
1589 | ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT) |
||
1590 | |||
1591 | /* Set size, cinuse and pinuse bit of this chunk */ |
||
1592 | #define set_size_and_pinuse_of_inuse_chunk(M, p, s)\ |
||
1593 | ((p)->head = (s|PINUSE_BIT|CINUSE_BIT)) |
||
1594 | |||
3297 | Serge | 1595 | #else /* FOOTERS */ |
1616 | serge | 1596 | |
3297 | Serge | 1597 | /* Set foot of inuse chunk to be xor of mstate and seed */ |
1598 | #define mark_inuse_foot(M,p,s)\ |
||
1599 | (((mchunkptr)((char*)(p) + (s)))->prev_foot = ((size_t)(M) ^ mparams.magic)) |
||
1616 | serge | 1600 | |
3297 | Serge | 1601 | #define get_mstate_for(p)\ |
1602 | ((mstate)(((mchunkptr)((char*)(p) +\ |
||
1603 | (chunksize(p))))->prev_foot ^ mparams.magic)) |
||
1616 | serge | 1604 | |
3297 | Serge | 1605 | #define set_inuse(M,p,s)\ |
1606 | ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\ |
||
1607 | (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT), \ |
||
1608 | mark_inuse_foot(M,p,s)) |
||
1616 | serge | 1609 | |
3297 | Serge | 1610 | #define set_inuse_and_pinuse(M,p,s)\ |
1611 | ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\ |
||
1612 | (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT),\ |
||
1613 | mark_inuse_foot(M,p,s)) |
||
1614 | |||
1615 | #define set_size_and_pinuse_of_inuse_chunk(M, p, s)\ |
||
1616 | ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\ |
||
1617 | mark_inuse_foot(M, p, s)) |
||
1618 | |||
1619 | #endif /* !FOOTERS */ |
||
1620 | |||
1621 | /* ---------------------------- setting mparams -------------------------- */ |
||
1622 | |||
1623 | #if LOCK_AT_FORK |
||
1624 | static void pre_fork(void) { ACQUIRE_LOCK(&(gm)->mutex); } |
||
1625 | static void post_fork_parent(void) { RELEASE_LOCK(&(gm)->mutex); } |
||
1626 | static void post_fork_child(void) { INITIAL_LOCK(&(gm)->mutex); } |
||
1627 | #endif /* LOCK_AT_FORK */ |
||
1628 | |||
1629 | /* Initialize mparams */ |
||
1630 | static int init_mparams(void) { |
||
1631 | |||
1632 | ACQUIRE_MALLOC_GLOBAL_LOCK(); |
||
1633 | if (mparams.magic == 0) { |
||
1634 | size_t magic; |
||
1635 | size_t psize; |
||
1636 | size_t gsize; |
||
1637 | |||
1638 | psize = 4096; |
||
1639 | gsize = ((DEFAULT_GRANULARITY != 0)? DEFAULT_GRANULARITY : psize); |
||
1640 | |||
1641 | mparams.granularity = gsize; |
||
1642 | mparams.page_size = psize; |
||
1643 | mparams.mmap_threshold = DEFAULT_MMAP_THRESHOLD; |
||
1644 | mparams.trim_threshold = DEFAULT_TRIM_THRESHOLD; |
||
1645 | mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT|USE_NONCONTIGUOUS_BIT; |
||
1646 | |||
1647 | /* Set up lock for main malloc area */ |
||
1648 | gm->mflags = mparams.default_mflags; |
||
1649 | MutexInit(&gm->lock); |
||
1650 | |||
1651 | { |
||
1652 | magic = (size_t)&magic ^ (size_t)0x55555555U; |
||
1653 | magic |= (size_t)8U; /* ensure nonzero */ |
||
1654 | magic &= ~(size_t)7U; /* improve chances of fault for bad values */ |
||
1655 | /* Until memory modes commonly available, use volatile-write */ |
||
1656 | (*(volatile size_t *)(&(mparams.magic))) = magic; |
||
1657 | } |
||
1658 | } |
||
1659 | |||
1660 | RELEASE_MALLOC_GLOBAL_LOCK(); |
||
1661 | return 1; |
||
1662 | } |
||
1663 | |||
1664 | |||
1665 | #if DEBUG |
||
1666 | /* ------------------------- Debugging Support --------------------------- */ |
||
1667 | |||
1668 | /* Check properties of any chunk, whether free, inuse, mmapped etc */ |
||
1669 | static void do_check_any_chunk(mstate m, mchunkptr p) { |
||
1670 | assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD)); |
||
1671 | assert(ok_address(m, p)); |
||
1672 | } |
||
1673 | |||
1674 | /* Check properties of top chunk */ |
||
1675 | static void do_check_top_chunk(mstate m, mchunkptr p) { |
||
1676 | msegmentptr sp = segment_holding(m, (char*)p); |
||
1677 | size_t sz = p->head & ~INUSE_BITS; /* third-lowest bit can be set! */ |
||
1678 | assert(sp != 0); |
||
1679 | assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD)); |
||
1680 | assert(ok_address(m, p)); |
||
1681 | assert(sz == m->topsize); |
||
1682 | assert(sz > 0); |
||
1683 | assert(sz == ((sp->base + sp->size) - (char*)p) - TOP_FOOT_SIZE); |
||
1684 | assert(pinuse(p)); |
||
1685 | assert(!pinuse(chunk_plus_offset(p, sz))); |
||
1686 | } |
||
1687 | |||
1688 | /* Check properties of (inuse) mmapped chunks */ |
||
1689 | static void do_check_mmapped_chunk(mstate m, mchunkptr p) { |
||
1690 | size_t sz = chunksize(p); |
||
1691 | size_t len = (sz + (p->prev_foot) + MMAP_FOOT_PAD); |
||
1692 | assert(is_mmapped(p)); |
||
1693 | assert(use_mmap(m)); |
||
1694 | assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD)); |
||
1695 | assert(ok_address(m, p)); |
||
1696 | assert(!is_small(sz)); |
||
1697 | assert((len & (mparams.page_size-SIZE_T_ONE)) == 0); |
||
1698 | assert(chunk_plus_offset(p, sz)->head == FENCEPOST_HEAD); |
||
1699 | assert(chunk_plus_offset(p, sz+SIZE_T_SIZE)->head == 0); |
||
1700 | } |
||
1701 | |||
1702 | /* Check properties of inuse chunks */ |
||
1703 | static void do_check_inuse_chunk(mstate m, mchunkptr p) { |
||
1704 | do_check_any_chunk(m, p); |
||
1705 | assert(is_inuse(p)); |
||
1706 | assert(next_pinuse(p)); |
||
1707 | /* If not pinuse and not mmapped, previous chunk has OK offset */ |
||
1708 | assert(is_mmapped(p) || pinuse(p) || next_chunk(prev_chunk(p)) == p); |
||
1709 | if (is_mmapped(p)) |
||
1710 | do_check_mmapped_chunk(m, p); |
||
1711 | } |
||
1712 | |||
1713 | /* Check properties of free chunks */ |
||
1714 | static void do_check_free_chunk(mstate m, mchunkptr p) { |
||
1715 | size_t sz = chunksize(p); |
||
1716 | mchunkptr next = chunk_plus_offset(p, sz); |
||
1717 | do_check_any_chunk(m, p); |
||
1718 | assert(!is_inuse(p)); |
||
1719 | assert(!next_pinuse(p)); |
||
1720 | assert (!is_mmapped(p)); |
||
1721 | if (p != m->dv && p != m->top) { |
||
1722 | if (sz >= MIN_CHUNK_SIZE) { |
||
1723 | assert((sz & CHUNK_ALIGN_MASK) == 0); |
||
1724 | assert(is_aligned(chunk2mem(p))); |
||
1725 | assert(next->prev_foot == sz); |
||
1726 | assert(pinuse(p)); |
||
1727 | assert (next == m->top || is_inuse(next)); |
||
1728 | assert(p->fd->bk == p); |
||
1729 | assert(p->bk->fd == p); |
||
1730 | } |
||
1731 | else /* markers are always of size SIZE_T_SIZE */ |
||
1732 | assert(sz == SIZE_T_SIZE); |
||
1733 | } |
||
1734 | } |
||
1735 | |||
1736 | /* Check properties of malloced chunks at the point they are malloced */ |
||
1737 | static void do_check_malloced_chunk(mstate m, void* mem, size_t s) { |
||
1738 | if (mem != 0) { |
||
1739 | mchunkptr p = mem2chunk(mem); |
||
1740 | size_t sz = p->head & ~INUSE_BITS; |
||
1741 | do_check_inuse_chunk(m, p); |
||
1742 | assert((sz & CHUNK_ALIGN_MASK) == 0); |
||
1743 | assert(sz >= MIN_CHUNK_SIZE); |
||
1744 | assert(sz >= s); |
||
1745 | /* unless mmapped, size is less than MIN_CHUNK_SIZE more than request */ |
||
1746 | assert(is_mmapped(p) || sz < (s + MIN_CHUNK_SIZE)); |
||
1747 | } |
||
1748 | } |
||
1749 | |||
1750 | /* Check a tree and its subtrees. */ |
||
1751 | static void do_check_tree(mstate m, tchunkptr t) { |
||
1752 | tchunkptr head = 0; |
||
1753 | tchunkptr u = t; |
||
1754 | bindex_t tindex = t->index; |
||
1755 | size_t tsize = chunksize(t); |
||
1756 | bindex_t idx; |
||
1757 | compute_tree_index(tsize, idx); |
||
1758 | assert(tindex == idx); |
||
1759 | assert(tsize >= MIN_LARGE_SIZE); |
||
1760 | assert(tsize >= minsize_for_tree_index(idx)); |
||
1761 | assert((idx == NTREEBINS-1) || (tsize < minsize_for_tree_index((idx+1)))); |
||
1762 | |||
1763 | do { /* traverse through chain of same-sized nodes */ |
||
1764 | do_check_any_chunk(m, ((mchunkptr)u)); |
||
1765 | assert(u->index == tindex); |
||
1766 | assert(chunksize(u) == tsize); |
||
1767 | assert(!is_inuse(u)); |
||
1768 | assert(!next_pinuse(u)); |
||
1769 | assert(u->fd->bk == u); |
||
1770 | assert(u->bk->fd == u); |
||
1771 | if (u->parent == 0) { |
||
1772 | assert(u->child[0] == 0); |
||
1773 | assert(u->child[1] == 0); |
||
1774 | } |
||
1775 | else { |
||
1776 | assert(head == 0); /* only one node on chain has parent */ |
||
1777 | head = u; |
||
1778 | assert(u->parent != u); |
||
1779 | assert (u->parent->child[0] == u || |
||
1780 | u->parent->child[1] == u || |
||
1781 | *((tbinptr*)(u->parent)) == u); |
||
1782 | if (u->child[0] != 0) { |
||
1783 | assert(u->child[0]->parent == u); |
||
1784 | assert(u->child[0] != u); |
||
1785 | do_check_tree(m, u->child[0]); |
||
1786 | } |
||
1787 | if (u->child[1] != 0) { |
||
1788 | assert(u->child[1]->parent == u); |
||
1789 | assert(u->child[1] != u); |
||
1790 | do_check_tree(m, u->child[1]); |
||
1791 | } |
||
1792 | if (u->child[0] != 0 && u->child[1] != 0) { |
||
1793 | assert(chunksize(u->child[0]) < chunksize(u->child[1])); |
||
1794 | } |
||
1795 | } |
||
1796 | u = u->fd; |
||
1797 | } while (u != t); |
||
1798 | assert(head != 0); |
||
1799 | } |
||
1800 | |||
1801 | /* Check all the chunks in a treebin. */ |
||
1802 | static void do_check_treebin(mstate m, bindex_t i) { |
||
1803 | tbinptr* tb = treebin_at(m, i); |
||
1804 | tchunkptr t = *tb; |
||
1805 | int empty = (m->treemap & (1U << i)) == 0; |
||
1806 | if (t == 0) |
||
1807 | assert(empty); |
||
1808 | if (!empty) |
||
1809 | do_check_tree(m, t); |
||
1810 | } |
||
1811 | |||
1812 | /* Check all the chunks in a smallbin. */ |
||
1813 | static void do_check_smallbin(mstate m, bindex_t i) { |
||
1814 | sbinptr b = smallbin_at(m, i); |
||
1815 | mchunkptr p = b->bk; |
||
1816 | unsigned int empty = (m->smallmap & (1U << i)) == 0; |
||
1817 | if (p == b) |
||
1818 | assert(empty); |
||
1819 | if (!empty) { |
||
1820 | for (; p != b; p = p->bk) { |
||
1821 | size_t size = chunksize(p); |
||
1822 | mchunkptr q; |
||
1823 | /* each chunk claims to be free */ |
||
1824 | do_check_free_chunk(m, p); |
||
1825 | /* chunk belongs in bin */ |
||
1826 | assert(small_index(size) == i); |
||
1827 | assert(p->bk == b || chunksize(p->bk) == chunksize(p)); |
||
1828 | /* chunk is followed by an inuse chunk */ |
||
1829 | q = next_chunk(p); |
||
1830 | if (q->head != FENCEPOST_HEAD) |
||
1831 | do_check_inuse_chunk(m, q); |
||
1832 | } |
||
1833 | } |
||
1834 | } |
||
1835 | |||
1836 | /* Find x in a bin. Used in other check functions. */ |
||
1837 | static int bin_find(mstate m, mchunkptr x) { |
||
1838 | size_t size = chunksize(x); |
||
1839 | if (is_small(size)) { |
||
1840 | bindex_t sidx = small_index(size); |
||
1841 | sbinptr b = smallbin_at(m, sidx); |
||
1842 | if (smallmap_is_marked(m, sidx)) { |
||
1843 | mchunkptr p = b; |
||
1844 | do { |
||
1845 | if (p == x) |
||
1846 | return 1; |
||
1847 | } while ((p = p->fd) != b); |
||
1848 | } |
||
1849 | } |
||
1850 | else { |
||
1851 | bindex_t tidx; |
||
1852 | compute_tree_index(size, tidx); |
||
1853 | if (treemap_is_marked(m, tidx)) { |
||
1854 | tchunkptr t = *treebin_at(m, tidx); |
||
1855 | size_t sizebits = size << leftshift_for_tree_index(tidx); |
||
1856 | while (t != 0 && chunksize(t) != size) { |
||
1857 | t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1]; |
||
1858 | sizebits <<= 1; |
||
1859 | } |
||
1860 | if (t != 0) { |
||
1861 | tchunkptr u = t; |
||
1862 | do { |
||
1863 | if (u == (tchunkptr)x) |
||
1864 | return 1; |
||
1865 | } while ((u = u->fd) != t); |
||
1866 | } |
||
1867 | } |
||
1868 | } |
||
1869 | return 0; |
||
1870 | } |
||
1871 | |||
1872 | /* Traverse each chunk and check it; return total */ |
||
1873 | static size_t traverse_and_check(mstate m) { |
||
1874 | size_t sum = 0; |
||
1875 | if (is_initialized(m)) { |
||
1876 | msegmentptr s = &m->seg; |
||
1877 | sum += m->topsize + TOP_FOOT_SIZE; |
||
1878 | while (s != 0) { |
||
1879 | mchunkptr q = align_as_chunk(s->base); |
||
1880 | mchunkptr lastq = 0; |
||
1881 | assert(pinuse(q)); |
||
1882 | while (segment_holds(s, q) && |
||
1883 | q != m->top && q->head != FENCEPOST_HEAD) { |
||
1884 | sum += chunksize(q); |
||
1885 | if (is_inuse(q)) { |
||
1886 | assert(!bin_find(m, q)); |
||
1887 | do_check_inuse_chunk(m, q); |
||
1888 | } |
||
1889 | else { |
||
1890 | assert(q == m->dv || bin_find(m, q)); |
||
1891 | assert(lastq == 0 || is_inuse(lastq)); /* Not 2 consecutive free */ |
||
1892 | do_check_free_chunk(m, q); |
||
1893 | } |
||
1894 | lastq = q; |
||
1895 | q = next_chunk(q); |
||
1896 | } |
||
1897 | s = s->next; |
||
1898 | } |
||
1899 | } |
||
1900 | return sum; |
||
1901 | } |
||
1902 | |||
1903 | |||
1904 | /* Check all properties of malloc_state. */ |
||
1905 | static void do_check_malloc_state(mstate m) { |
||
1906 | bindex_t i; |
||
1907 | size_t total; |
||
1908 | /* check bins */ |
||
1909 | for (i = 0; i < NSMALLBINS; ++i) |
||
1910 | do_check_smallbin(m, i); |
||
1911 | for (i = 0; i < NTREEBINS; ++i) |
||
1912 | do_check_treebin(m, i); |
||
1913 | |||
1914 | if (m->dvsize != 0) { /* check dv chunk */ |
||
1915 | do_check_any_chunk(m, m->dv); |
||
1916 | assert(m->dvsize == chunksize(m->dv)); |
||
1917 | assert(m->dvsize >= MIN_CHUNK_SIZE); |
||
1918 | assert(bin_find(m, m->dv) == 0); |
||
1919 | } |
||
1920 | |||
1921 | if (m->top != 0) { /* check top chunk */ |
||
1922 | do_check_top_chunk(m, m->top); |
||
1923 | /*assert(m->topsize == chunksize(m->top)); redundant */ |
||
1924 | assert(m->topsize > 0); |
||
1925 | assert(bin_find(m, m->top) == 0); |
||
1926 | } |
||
1927 | |||
1928 | total = traverse_and_check(m); |
||
1929 | assert(total <= m->footprint); |
||
1930 | assert(m->footprint <= m->max_footprint); |
||
1931 | } |
||
1932 | #endif /* DEBUG */ |
||
1933 | |||
1616 | serge | 1934 | #define CORRUPTION_ERROR_ACTION(m) \ |
1935 | do { \ |
||
1936 | printf("%s malloc heap corrupted\n",__FUNCTION__); \ |
||
1937 | while(1) \ |
||
1938 | { \ |
||
1939 | delay(100); \ |
||
1940 | } \ |
||
1941 | }while(0) \ |
||
1942 | |||
1943 | |||
1944 | #define USAGE_ERROR_ACTION(m, p) \ |
||
1945 | do { \ |
||
1946 | printf("%s malloc heap corrupted\n",__FUNCTION__); \ |
||
1947 | while(1) \ |
||
1948 | { \ |
||
1949 | delay(100); \ |
||
1950 | } \ |
||
1951 | }while(0) \ |
||
1952 | |||
1953 | /* ----------------------- Operations on smallbins ----------------------- */ |
||
1954 | |||
1955 | /* |
||
1956 | Various forms of linking and unlinking are defined as macros. Even |
||
1957 | the ones for trees, which are very long but have very short typical |
||
1958 | paths. This is ugly but reduces reliance on inlining support of |
||
1959 | compilers. |
||
1960 | */ |
||
1961 | |||
1962 | /* Link a free chunk into a smallbin */ |
||
1963 | #define insert_small_chunk(M, P, S) {\ |
||
1964 | bindex_t I = small_index(S);\ |
||
1965 | mchunkptr B = smallbin_at(M, I);\ |
||
1966 | mchunkptr F = B;\ |
||
1967 | assert(S >= MIN_CHUNK_SIZE);\ |
||
1968 | if (!smallmap_is_marked(M, I))\ |
||
1969 | mark_smallmap(M, I);\ |
||
1970 | else if (RTCHECK(ok_address(M, B->fd)))\ |
||
1971 | F = B->fd;\ |
||
1972 | else {\ |
||
1973 | CORRUPTION_ERROR_ACTION(M);\ |
||
1974 | }\ |
||
1975 | B->fd = P;\ |
||
1976 | F->bk = P;\ |
||
1977 | P->fd = F;\ |
||
1978 | P->bk = B;\ |
||
1979 | } |
||
3297 | Serge | 1980 | /* ----------------------- Operations on smallbins ----------------------- */ |
1616 | serge | 1981 | |
3297 | Serge | 1982 | /* |
1983 | Various forms of linking and unlinking are defined as macros. Even |
||
1984 | the ones for trees, which are very long but have very short typical |
||
1985 | paths. This is ugly but reduces reliance on inlining support of |
||
1986 | compilers. |
||
1987 | */ |
||
1988 | |||
1989 | /* Link a free chunk into a smallbin */ |
||
1990 | #define insert_small_chunk(M, P, S) {\ |
||
1991 | bindex_t I = small_index(S);\ |
||
1992 | mchunkptr B = smallbin_at(M, I);\ |
||
1993 | mchunkptr F = B;\ |
||
1994 | assert(S >= MIN_CHUNK_SIZE);\ |
||
1995 | if (!smallmap_is_marked(M, I))\ |
||
1996 | mark_smallmap(M, I);\ |
||
1997 | else if (RTCHECK(ok_address(M, B->fd)))\ |
||
1998 | F = B->fd;\ |
||
1999 | else {\ |
||
2000 | CORRUPTION_ERROR_ACTION(M);\ |
||
2001 | }\ |
||
2002 | B->fd = P;\ |
||
2003 | F->bk = P;\ |
||
2004 | P->fd = F;\ |
||
2005 | P->bk = B;\ |
||
2006 | } |
||
2007 | |||
1616 | serge | 2008 | /* Unlink a chunk from a smallbin */ |
2009 | #define unlink_small_chunk(M, P, S) {\ |
||
2010 | mchunkptr F = P->fd;\ |
||
2011 | mchunkptr B = P->bk;\ |
||
2012 | bindex_t I = small_index(S);\ |
||
2013 | assert(P != B);\ |
||
2014 | assert(P != F);\ |
||
2015 | assert(chunksize(P) == small_index2size(I));\ |
||
3297 | Serge | 2016 | if (RTCHECK(F == smallbin_at(M,I) || (ok_address(M, F) && F->bk == P))) { \ |
2017 | if (B == F) {\ |
||
1616 | serge | 2018 | clear_smallmap(M, I);\ |
3297 | Serge | 2019 | }\ |
2020 | else if (RTCHECK(B == smallbin_at(M,I) ||\ |
||
2021 | (ok_address(M, B) && B->fd == P))) {\ |
||
1616 | serge | 2022 | F->bk = B;\ |
2023 | B->fd = F;\ |
||
2024 | }\ |
||
2025 | else {\ |
||
2026 | CORRUPTION_ERROR_ACTION(M);\ |
||
2027 | }\ |
||
3297 | Serge | 2028 | }\ |
2029 | else {\ |
||
2030 | CORRUPTION_ERROR_ACTION(M);\ |
||
2031 | }\ |
||
1616 | serge | 2032 | } |
2033 | |||
2034 | /* Unlink the first chunk from a smallbin */ |
||
2035 | #define unlink_first_small_chunk(M, B, P, I) {\ |
||
2036 | mchunkptr F = P->fd;\ |
||
2037 | assert(P != B);\ |
||
2038 | assert(P != F);\ |
||
2039 | assert(chunksize(P) == small_index2size(I));\ |
||
3297 | Serge | 2040 | if (B == F) {\ |
1616 | serge | 2041 | clear_smallmap(M, I);\ |
3297 | Serge | 2042 | }\ |
2043 | else if (RTCHECK(ok_address(M, F) && F->bk == P)) {\ |
||
2044 | F->bk = B;\ |
||
1616 | serge | 2045 | B->fd = F;\ |
2046 | }\ |
||
2047 | else {\ |
||
2048 | CORRUPTION_ERROR_ACTION(M);\ |
||
2049 | }\ |
||
2050 | } |
||
2051 | |||
2052 | /* Replace dv node, binning the old one */ |
||
2053 | /* Used only when dvsize known to be small */ |
||
2054 | #define replace_dv(M, P, S) {\ |
||
2055 | size_t DVS = M->dvsize;\ |
||
3297 | Serge | 2056 | assert(is_small(DVS));\ |
1616 | serge | 2057 | if (DVS != 0) {\ |
2058 | mchunkptr DV = M->dv;\ |
||
2059 | insert_small_chunk(M, DV, DVS);\ |
||
2060 | }\ |
||
2061 | M->dvsize = S;\ |
||
2062 | M->dv = P;\ |
||
2063 | } |
||
2064 | |||
2065 | /* ------------------------- Operations on trees ------------------------- */ |
||
2066 | |||
2067 | /* Insert chunk into tree */ |
||
2068 | #define insert_large_chunk(M, X, S) {\ |
||
2069 | tbinptr* H;\ |
||
2070 | bindex_t I;\ |
||
2071 | compute_tree_index(S, I);\ |
||
2072 | H = treebin_at(M, I);\ |
||
2073 | X->index = I;\ |
||
2074 | X->child[0] = X->child[1] = 0;\ |
||
2075 | if (!treemap_is_marked(M, I)) {\ |
||
2076 | mark_treemap(M, I);\ |
||
2077 | *H = X;\ |
||
2078 | X->parent = (tchunkptr)H;\ |
||
2079 | X->fd = X->bk = X;\ |
||
2080 | }\ |
||
2081 | else {\ |
||
2082 | tchunkptr T = *H;\ |
||
2083 | size_t K = S << leftshift_for_tree_index(I);\ |
||
2084 | for (;;) {\ |
||
2085 | if (chunksize(T) != S) {\ |
||
2086 | tchunkptr* C = &(T->child[(K >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1]);\ |
||
2087 | K <<= 1;\ |
||
2088 | if (*C != 0)\ |
||
2089 | T = *C;\ |
||
2090 | else if (RTCHECK(ok_address(M, C))) {\ |
||
2091 | *C = X;\ |
||
2092 | X->parent = T;\ |
||
2093 | X->fd = X->bk = X;\ |
||
2094 | break;\ |
||
2095 | }\ |
||
2096 | else {\ |
||
2097 | CORRUPTION_ERROR_ACTION(M);\ |
||
2098 | break;\ |
||
2099 | }\ |
||
2100 | }\ |
||
2101 | else {\ |
||
2102 | tchunkptr F = T->fd;\ |
||
2103 | if (RTCHECK(ok_address(M, T) && ok_address(M, F))) {\ |
||
2104 | T->fd = F->bk = X;\ |
||
2105 | X->fd = F;\ |
||
2106 | X->bk = T;\ |
||
2107 | X->parent = 0;\ |
||
2108 | break;\ |
||
2109 | }\ |
||
2110 | else {\ |
||
2111 | CORRUPTION_ERROR_ACTION(M);\ |
||
2112 | break;\ |
||
2113 | }\ |
||
2114 | }\ |
||
2115 | }\ |
||
2116 | }\ |
||
2117 | } |
||
2118 | |||
2119 | /* |
||
2120 | Unlink steps: |
||
2121 | |||
2122 | 1. If x is a chained node, unlink it from its same-sized fd/bk links |
||
2123 | and choose its bk node as its replacement. |
||
2124 | 2. If x was the last node of its size, but not a leaf node, it must |
||
2125 | be replaced with a leaf node (not merely one with an open left or |
||
2126 | right), to make sure that lefts and rights of descendents |
||
2127 | correspond properly to bit masks. We use the rightmost descendent |
||
2128 | of x. We could use any other leaf, but this is easy to locate and |
||
2129 | tends to counteract removal of leftmosts elsewhere, and so keeps |
||
2130 | paths shorter than minimally guaranteed. This doesn't loop much |
||
2131 | because on average a node in a tree is near the bottom. |
||
2132 | 3. If x is the base of a chain (i.e., has parent links) relink |
||
2133 | x's parent and children to x's replacement (or null if none). |
||
2134 | */ |
||
2135 | |||
2136 | #define unlink_large_chunk(M, X) {\ |
||
2137 | tchunkptr XP = X->parent;\ |
||
2138 | tchunkptr R;\ |
||
2139 | if (X->bk != X) {\ |
||
2140 | tchunkptr F = X->fd;\ |
||
2141 | R = X->bk;\ |
||
3297 | Serge | 2142 | if (RTCHECK(ok_address(M, F) && F->bk == X && R->fd == X)) {\ |
1616 | serge | 2143 | F->bk = R;\ |
2144 | R->fd = F;\ |
||
2145 | }\ |
||
2146 | else {\ |
||
2147 | CORRUPTION_ERROR_ACTION(M);\ |
||
2148 | }\ |
||
2149 | }\ |
||
2150 | else {\ |
||
2151 | tchunkptr* RP;\ |
||
2152 | if (((R = *(RP = &(X->child[1]))) != 0) ||\ |
||
2153 | ((R = *(RP = &(X->child[0]))) != 0)) {\ |
||
2154 | tchunkptr* CP;\ |
||
2155 | while ((*(CP = &(R->child[1])) != 0) ||\ |
||
2156 | (*(CP = &(R->child[0])) != 0)) {\ |
||
2157 | R = *(RP = CP);\ |
||
2158 | }\ |
||
2159 | if (RTCHECK(ok_address(M, RP)))\ |
||
2160 | *RP = 0;\ |
||
2161 | else {\ |
||
2162 | CORRUPTION_ERROR_ACTION(M);\ |
||
2163 | }\ |
||
2164 | }\ |
||
2165 | }\ |
||
2166 | if (XP != 0) {\ |
||
2167 | tbinptr* H = treebin_at(M, X->index);\ |
||
2168 | if (X == *H) {\ |
||
2169 | if ((*H = R) == 0) \ |
||
2170 | clear_treemap(M, X->index);\ |
||
2171 | }\ |
||
2172 | else if (RTCHECK(ok_address(M, XP))) {\ |
||
2173 | if (XP->child[0] == X) \ |
||
2174 | XP->child[0] = R;\ |
||
2175 | else \ |
||
2176 | XP->child[1] = R;\ |
||
2177 | }\ |
||
2178 | else\ |
||
2179 | CORRUPTION_ERROR_ACTION(M);\ |
||
2180 | if (R != 0) {\ |
||
2181 | if (RTCHECK(ok_address(M, R))) {\ |
||
2182 | tchunkptr C0, C1;\ |
||
2183 | R->parent = XP;\ |
||
2184 | if ((C0 = X->child[0]) != 0) {\ |
||
2185 | if (RTCHECK(ok_address(M, C0))) {\ |
||
2186 | R->child[0] = C0;\ |
||
2187 | C0->parent = R;\ |
||
2188 | }\ |
||
2189 | else\ |
||
2190 | CORRUPTION_ERROR_ACTION(M);\ |
||
2191 | }\ |
||
2192 | if ((C1 = X->child[1]) != 0) {\ |
||
2193 | if (RTCHECK(ok_address(M, C1))) {\ |
||
2194 | R->child[1] = C1;\ |
||
2195 | C1->parent = R;\ |
||
2196 | }\ |
||
2197 | else\ |
||
2198 | CORRUPTION_ERROR_ACTION(M);\ |
||
2199 | }\ |
||
2200 | }\ |
||
2201 | else\ |
||
2202 | CORRUPTION_ERROR_ACTION(M);\ |
||
2203 | }\ |
||
2204 | }\ |
||
2205 | } |
||
2206 | |||
2207 | /* Relays to large vs small bin operations */ |
||
2208 | |||
2209 | #define insert_chunk(M, P, S)\ |
||
2210 | if (is_small(S)) insert_small_chunk(M, P, S)\ |
||
2211 | else { tchunkptr TP = (tchunkptr)(P); insert_large_chunk(M, TP, S); } |
||
2212 | |||
2213 | #define unlink_chunk(M, P, S)\ |
||
2214 | if (is_small(S)) unlink_small_chunk(M, P, S)\ |
||
2215 | else { tchunkptr TP = (tchunkptr)(P); unlink_large_chunk(M, TP); } |
||
2216 | |||
2217 | |||
3391 | Serge | 2218 | /* Relays to internal calls to malloc/free from realloc, memalign etc */ |
1616 | serge | 2219 | |
3391 | Serge | 2220 | #if ONLY_MSPACES |
2221 | #define internal_malloc(m, b) mspace_malloc(m, b) |
||
2222 | #define internal_free(m, mem) mspace_free(m,mem); |
||
2223 | #else /* ONLY_MSPACES */ |
||
2224 | #if MSPACES |
||
2225 | #define internal_malloc(m, b)\ |
||
2226 | ((m == gm)? dlmalloc(b) : mspace_malloc(m, b)) |
||
2227 | #define internal_free(m, mem)\ |
||
2228 | if (m == gm) dlfree(mem); else mspace_free(m,mem); |
||
2229 | #else /* MSPACES */ |
||
2230 | #define internal_malloc(m, b) malloc(b) |
||
2231 | #define internal_free(m, mem) free(mem) |
||
2232 | #endif /* MSPACES */ |
||
2233 | #endif /* ONLY_MSPACES */ |
||
1616 | serge | 2234 | |
2235 | |||
2236 | static inline void* os_mmap(size_t size) |
||
2237 | { |
||
2238 | void* ptr = KernelAlloc(size); |
||
3039 | serge | 2239 | printf("%s %x %d bytes\n",__FUNCTION__, ptr, size); |
1616 | serge | 2240 | return (ptr != 0)? ptr: MFAIL; |
2241 | } |
||
2242 | |||
2243 | static inline int os_munmap(void* ptr, size_t size) |
||
2244 | { |
||
2245 | return (KernelFree(ptr) != 0) ? 0 : -1; |
||
2246 | } |
||
2247 | |||
2248 | |||
2249 | #define MMAP_DEFAULT(s) os_mmap(s) |
||
2250 | #define MUNMAP_DEFAULT(a, s) os_munmap((a), (s)) |
||
2251 | #define DIRECT_MMAP_DEFAULT(s) os_mmap(s) |
||
2252 | |||
2253 | |||
2254 | /* ----------------------- Direct-mmapping chunks ----------------------- */ |
||
2255 | |||
2256 | /* |
||
2257 | Directly mmapped chunks are set up with an offset to the start of |
||
2258 | the mmapped region stored in the prev_foot field of the chunk. This |
||
2259 | allows reconstruction of the required argument to MUNMAP when freed, |
||
2260 | and also allows adjustment of the returned chunk to meet alignment |
||
2261 | requirements (especially in memalign). |
||
2262 | */ |
||
2263 | |||
2264 | /* Malloc using mmap */ |
||
3297 | Serge | 2265 | static void* mmap_alloc(mstate m, size_t nb) { |
1616 | serge | 2266 | size_t mmsize = mmap_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK); |
3297 | Serge | 2267 | if (m->footprint_limit != 0) { |
2268 | size_t fp = m->footprint + mmsize; |
||
2269 | if (fp <= m->footprint || fp > m->footprint_limit) |
||
2270 | return 0; |
||
2271 | } |
||
2272 | if (mmsize > nb) { /* Check for wrap around 0 */ |
||
2273 | char* mm = (char*)(CALL_DIRECT_MMAP(mmsize)); |
||
2274 | if (mm != CMFAIL) { |
||
1616 | serge | 2275 | size_t offset = align_offset(chunk2mem(mm)); |
2276 | size_t psize = mmsize - offset - MMAP_FOOT_PAD; |
||
2277 | mchunkptr p = (mchunkptr)(mm + offset); |
||
2278 | p->prev_foot = offset; |
||
2279 | p->head = psize; |
||
2280 | mark_inuse_foot(m, p, psize); |
||
2281 | chunk_plus_offset(p, psize)->head = FENCEPOST_HEAD; |
||
2282 | chunk_plus_offset(p, psize+SIZE_T_SIZE)->head = 0; |
||
2283 | |||
2284 | if (m->least_addr == 0 || mm < m->least_addr) |
||
2285 | m->least_addr = mm; |
||
2286 | if ((m->footprint += mmsize) > m->max_footprint) |
||
2287 | m->max_footprint = m->footprint; |
||
2288 | assert(is_aligned(chunk2mem(p))); |
||
2289 | check_mmapped_chunk(m, p); |
||
2290 | return chunk2mem(p); |
||
2291 | } |
||
2292 | } |
||
2293 | return 0; |
||
2294 | } |
||
2295 | |||
2296 | /* Realloc using mmap */ |
||
3297 | Serge | 2297 | static mchunkptr mmap_resize(mstate m, mchunkptr oldp, size_t nb, int flags) { |
1616 | serge | 2298 | size_t oldsize = chunksize(oldp); |
3297 | Serge | 2299 | (void)flags; /* placate people compiling -Wunused */ |
1616 | serge | 2300 | if (is_small(nb)) /* Can't shrink mmap regions below small size */ |
2301 | return 0; |
||
2302 | /* Keep old chunk if big enough but not too big */ |
||
2303 | if (oldsize >= nb + SIZE_T_SIZE && |
||
2304 | (oldsize - nb) <= (mparams.granularity << 1)) |
||
2305 | return oldp; |
||
3297 | Serge | 2306 | else { |
1616 | serge | 2307 | size_t offset = oldp->prev_foot; |
2308 | size_t oldmmsize = oldsize + offset + MMAP_FOOT_PAD; |
||
2309 | size_t newmmsize = mmap_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK); |
||
2310 | char* cp = (char*)CALL_MREMAP((char*)oldp - offset, |
||
3297 | Serge | 2311 | oldmmsize, newmmsize, flags); |
2312 | if (cp != CMFAIL) { |
||
1616 | serge | 2313 | mchunkptr newp = (mchunkptr)(cp + offset); |
2314 | size_t psize = newmmsize - offset - MMAP_FOOT_PAD; |
||
2315 | newp->head = psize; |
||
2316 | mark_inuse_foot(m, newp, psize); |
||
2317 | chunk_plus_offset(newp, psize)->head = FENCEPOST_HEAD; |
||
2318 | chunk_plus_offset(newp, psize+SIZE_T_SIZE)->head = 0; |
||
2319 | |||
3297 | Serge | 2320 | if (cp < m->least_addr) |
2321 | m->least_addr = cp; |
||
2322 | if ((m->footprint += newmmsize - oldmmsize) > m->max_footprint) |
||
2323 | m->max_footprint = m->footprint; |
||
2324 | check_mmapped_chunk(m, newp); |
||
2325 | return newp; |
||
1616 | serge | 2326 | } |
3297 | Serge | 2327 | } |
2328 | return 0; |
||
1616 | serge | 2329 | } |
2330 | |||
2331 | |||
2332 | /* -------------------------- mspace management -------------------------- */ |
||
2333 | |||
2334 | /* Initialize top chunk and its size */ |
||
3297 | Serge | 2335 | static void init_top(mstate m, mchunkptr p, size_t psize) { |
1616 | serge | 2336 | /* Ensure alignment */ |
2337 | size_t offset = align_offset(chunk2mem(p)); |
||
2338 | p = (mchunkptr)((char*)p + offset); |
||
2339 | psize -= offset; |
||
2340 | |||
2341 | m->top = p; |
||
2342 | m->topsize = psize; |
||
2343 | p->head = psize | PINUSE_BIT; |
||
2344 | /* set size of fake trailing chunk holding overhead space only once */ |
||
2345 | chunk_plus_offset(p, psize)->head = TOP_FOOT_SIZE; |
||
2346 | m->trim_check = mparams.trim_threshold; /* reset on each update */ |
||
2347 | } |
||
2348 | |||
2349 | /* Initialize bins for a new mstate that is otherwise zeroed out */ |
||
3297 | Serge | 2350 | static void init_bins(mstate m) { |
1616 | serge | 2351 | /* Establish circular links for smallbins */ |
2352 | bindex_t i; |
||
2353 | for (i = 0; i < NSMALLBINS; ++i) { |
||
2354 | sbinptr bin = smallbin_at(m,i); |
||
2355 | bin->fd = bin->bk = bin; |
||
2356 | } |
||
2357 | } |
||
2358 | |||
2359 | /* Allocate chunk and prepend remainder with chunk in successor base. */ |
||
2360 | static void* prepend_alloc(mstate m, char* newbase, char* oldbase, |
||
3297 | Serge | 2361 | size_t nb) { |
1616 | serge | 2362 | mchunkptr p = align_as_chunk(newbase); |
2363 | mchunkptr oldfirst = align_as_chunk(oldbase); |
||
2364 | size_t psize = (char*)oldfirst - (char*)p; |
||
2365 | mchunkptr q = chunk_plus_offset(p, nb); |
||
2366 | size_t qsize = psize - nb; |
||
2367 | set_size_and_pinuse_of_inuse_chunk(m, p, nb); |
||
2368 | |||
2369 | assert((char*)oldfirst > (char*)q); |
||
2370 | assert(pinuse(oldfirst)); |
||
2371 | assert(qsize >= MIN_CHUNK_SIZE); |
||
2372 | |||
2373 | /* consolidate remainder with first chunk of old base */ |
||
2374 | if (oldfirst == m->top) { |
||
2375 | size_t tsize = m->topsize += qsize; |
||
2376 | m->top = q; |
||
2377 | q->head = tsize | PINUSE_BIT; |
||
2378 | check_top_chunk(m, q); |
||
2379 | } |
||
2380 | else if (oldfirst == m->dv) { |
||
2381 | size_t dsize = m->dvsize += qsize; |
||
2382 | m->dv = q; |
||
2383 | set_size_and_pinuse_of_free_chunk(q, dsize); |
||
2384 | } |
||
2385 | else { |
||
2386 | if (!is_inuse(oldfirst)) { |
||
2387 | size_t nsize = chunksize(oldfirst); |
||
2388 | unlink_chunk(m, oldfirst, nsize); |
||
2389 | oldfirst = chunk_plus_offset(oldfirst, nsize); |
||
2390 | qsize += nsize; |
||
2391 | } |
||
2392 | set_free_with_pinuse(q, qsize, oldfirst); |
||
2393 | insert_chunk(m, q, qsize); |
||
2394 | check_free_chunk(m, q); |
||
2395 | } |
||
2396 | |||
2397 | check_malloced_chunk(m, chunk2mem(p), nb); |
||
2398 | return chunk2mem(p); |
||
2399 | } |
||
2400 | |||
2401 | /* Add a segment to hold a new noncontiguous region */ |
||
3297 | Serge | 2402 | static void add_segment(mstate m, char* tbase, size_t tsize, flag_t mmapped) { |
1616 | serge | 2403 | /* Determine locations and sizes of segment, fenceposts, old top */ |
2404 | char* old_top = (char*)m->top; |
||
2405 | msegmentptr oldsp = segment_holding(m, old_top); |
||
2406 | char* old_end = oldsp->base + oldsp->size; |
||
2407 | size_t ssize = pad_request(sizeof(struct malloc_segment)); |
||
2408 | char* rawsp = old_end - (ssize + FOUR_SIZE_T_SIZES + CHUNK_ALIGN_MASK); |
||
2409 | size_t offset = align_offset(chunk2mem(rawsp)); |
||
2410 | char* asp = rawsp + offset; |
||
2411 | char* csp = (asp < (old_top + MIN_CHUNK_SIZE))? old_top : asp; |
||
2412 | mchunkptr sp = (mchunkptr)csp; |
||
2413 | msegmentptr ss = (msegmentptr)(chunk2mem(sp)); |
||
2414 | mchunkptr tnext = chunk_plus_offset(sp, ssize); |
||
2415 | mchunkptr p = tnext; |
||
2416 | int nfences = 0; |
||
2417 | |||
2418 | /* reset top to new space */ |
||
2419 | init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE); |
||
2420 | |||
2421 | /* Set up segment record */ |
||
2422 | assert(is_aligned(ss)); |
||
2423 | set_size_and_pinuse_of_inuse_chunk(m, sp, ssize); |
||
2424 | *ss = m->seg; /* Push current record */ |
||
2425 | m->seg.base = tbase; |
||
2426 | m->seg.size = tsize; |
||
2427 | m->seg.sflags = mmapped; |
||
2428 | m->seg.next = ss; |
||
2429 | |||
2430 | /* Insert trailing fenceposts */ |
||
2431 | for (;;) { |
||
2432 | mchunkptr nextp = chunk_plus_offset(p, SIZE_T_SIZE); |
||
2433 | p->head = FENCEPOST_HEAD; |
||
2434 | ++nfences; |
||
2435 | if ((char*)(&(nextp->head)) < old_end) |
||
2436 | p = nextp; |
||
2437 | else |
||
2438 | break; |
||
2439 | } |
||
2440 | assert(nfences >= 2); |
||
2441 | |||
2442 | /* Insert the rest of old top into a bin as an ordinary free chunk */ |
||
2443 | if (csp != old_top) { |
||
2444 | mchunkptr q = (mchunkptr)old_top; |
||
2445 | size_t psize = csp - old_top; |
||
2446 | mchunkptr tn = chunk_plus_offset(q, psize); |
||
2447 | set_free_with_pinuse(q, psize, tn); |
||
2448 | insert_chunk(m, q, psize); |
||
2449 | } |
||
2450 | |||
2451 | check_top_chunk(m, m->top); |
||
2452 | } |
||
2453 | |||
2454 | /* -------------------------- System allocation -------------------------- */ |
||
2455 | |||
2456 | /* Get memory from system using MORECORE or MMAP */ |
||
3297 | Serge | 2457 | static void* sys_alloc(mstate m, size_t nb) { |
1616 | serge | 2458 | char* tbase = CMFAIL; |
2459 | size_t tsize = 0; |
||
2460 | flag_t mmap_flag = 0; |
||
3297 | Serge | 2461 | size_t asize; /* allocation size */ |
1616 | serge | 2462 | |
2463 | ensure_initialization(); |
||
2464 | |||
3039 | serge | 2465 | printf("%s %d bytes\n", __FUNCTION__, nb); |
2466 | |||
1616 | serge | 2467 | /* Directly map large chunks, but only if already initialized */ |
3297 | Serge | 2468 | if (use_mmap(m) && nb >= mparams.mmap_threshold && m->topsize != 0) { |
1616 | serge | 2469 | void* mem = mmap_alloc(m, nb); |
2470 | if (mem != 0) |
||
2471 | return mem; |
||
2472 | } |
||
2473 | |||
3297 | Serge | 2474 | asize = granularity_align(nb + SYS_ALLOC_PADDING); |
2475 | if (asize <= nb) |
||
2476 | return 0; /* wraparound */ |
||
2477 | if (m->footprint_limit != 0) { |
||
2478 | size_t fp = m->footprint + asize; |
||
2479 | if (fp <= m->footprint || fp > m->footprint_limit) |
||
2480 | return 0; |
||
2481 | } |
||
2482 | |||
1616 | serge | 2483 | /* |
2484 | Try getting memory in any of three ways (in most-preferred to |
||
2485 | least-preferred order): |
||
2486 | 1. A call to MORECORE that can normally contiguously extend memory. |
||
2487 | (disabled if not MORECORE_CONTIGUOUS or not HAVE_MORECORE or |
||
2488 | or main space is mmapped or a previous contiguous call failed) |
||
2489 | 2. A call to MMAP new space (disabled if not HAVE_MMAP). |
||
2490 | Note that under the default settings, if MORECORE is unable to |
||
2491 | fulfill a request, and HAVE_MMAP is true, then mmap is |
||
2492 | used as a noncontiguous system allocator. This is a useful backup |
||
2493 | strategy for systems with holes in address spaces -- in this case |
||
2494 | sbrk cannot contiguously expand the heap, but mmap may be able to |
||
2495 | find space. |
||
2496 | 3. A call to MORECORE that cannot usually contiguously extend memory. |
||
2497 | (disabled if not HAVE_MORECORE) |
||
2498 | |||
2499 | In all cases, we need to request enough bytes from system to ensure |
||
2500 | we can malloc nb bytes upon success, so pad with enough space for |
||
2501 | top_foot, plus alignment-pad to make sure we don't lose bytes if |
||
2502 | not on boundary, and round this up to a granularity unit. |
||
2503 | */ |
||
2504 | |||
3297 | Serge | 2505 | #if 0 |
2506 | if (MORECORE_CONTIGUOUS && !use_noncontiguous(m)) { |
||
2507 | char* br = CMFAIL; |
||
2508 | size_t ssize = asize; /* sbrk call size */ |
||
2509 | msegmentptr ss = (m->top == 0)? 0 : segment_holding(m, (char*)m->top); |
||
2510 | ACQUIRE_MALLOC_GLOBAL_LOCK(); |
||
2511 | |||
2512 | if (ss == 0) { /* First time through or recovery */ |
||
2513 | char* base = (char*)CALL_MORECORE(0); |
||
2514 | if (base != CMFAIL) { |
||
2515 | size_t fp; |
||
2516 | /* Adjust to end on a page boundary */ |
||
2517 | if (!is_page_aligned(base)) |
||
2518 | ssize += (page_align((size_t)base) - (size_t)base); |
||
2519 | fp = m->footprint + ssize; /* recheck limits */ |
||
2520 | if (ssize > nb && ssize < HALF_MAX_SIZE_T && |
||
2521 | (m->footprint_limit == 0 || |
||
2522 | (fp > m->footprint && fp <= m->footprint_limit)) && |
||
2523 | (br = (char*)(CALL_MORECORE(ssize))) == base) { |
||
2524 | tbase = base; |
||
2525 | tsize = ssize; |
||
2526 | } |
||
2527 | } |
||
2528 | } |
||
2529 | else { |
||
2530 | /* Subtract out existing available top space from MORECORE request. */ |
||
2531 | ssize = granularity_align(nb - m->topsize + SYS_ALLOC_PADDING); |
||
2532 | /* Use mem here only if it did continuously extend old space */ |
||
2533 | if (ssize < HALF_MAX_SIZE_T && |
||
2534 | (br = (char*)(CALL_MORECORE(ssize))) == ss->base+ss->size) { |
||
2535 | tbase = br; |
||
2536 | tsize = ssize; |
||
2537 | } |
||
2538 | } |
||
2539 | |||
2540 | if (tbase == CMFAIL) { /* Cope with partial failure */ |
||
2541 | if (br != CMFAIL) { /* Try to use/extend the space we did get */ |
||
2542 | if (ssize < HALF_MAX_SIZE_T && |
||
2543 | ssize < nb + SYS_ALLOC_PADDING) { |
||
2544 | size_t esize = granularity_align(nb + SYS_ALLOC_PADDING - ssize); |
||
2545 | if (esize < HALF_MAX_SIZE_T) { |
||
2546 | char* end = (char*)CALL_MORECORE(esize); |
||
2547 | if (end != CMFAIL) |
||
2548 | ssize += esize; |
||
2549 | else { /* Can't use; try to release */ |
||
2550 | (void) CALL_MORECORE(-ssize); |
||
2551 | br = CMFAIL; |
||
1616 | serge | 2552 | } |
3297 | Serge | 2553 | } |
1616 | serge | 2554 | } |
3297 | Serge | 2555 | } |
2556 | if (br != CMFAIL) { /* Use the space we did get */ |
||
2557 | tbase = br; |
||
2558 | tsize = ssize; |
||
2559 | } |
||
2560 | else |
||
2561 | disable_contiguous(m); /* Don't try contiguous path in the future */ |
||
1616 | serge | 2562 | } |
2563 | |||
3297 | Serge | 2564 | RELEASE_MALLOC_GLOBAL_LOCK(); |
2565 | } |
||
2566 | #endif |
||
1616 | serge | 2567 | |
3297 | Serge | 2568 | if (HAVE_MMAP && tbase == CMFAIL) { /* Try MMAP */ |
2569 | char* mp = (char*)(CALL_MMAP(asize)); |
||
2570 | if (mp != CMFAIL) { |
||
2571 | tbase = mp; |
||
2572 | tsize = asize; |
||
2573 | mmap_flag = USE_MMAP_BIT; |
||
2574 | } |
||
2575 | } |
||
1616 | serge | 2576 | |
3297 | Serge | 2577 | #if 0 |
2578 | if (HAVE_MORECORE && tbase == CMFAIL) { /* Try noncontiguous MORECORE */ |
||
2579 | if (asize < HALF_MAX_SIZE_T) { |
||
2580 | char* br = CMFAIL; |
||
2581 | char* end = CMFAIL; |
||
2582 | ACQUIRE_MALLOC_GLOBAL_LOCK(); |
||
2583 | br = (char*)(CALL_MORECORE(asize)); |
||
2584 | end = (char*)(CALL_MORECORE(0)); |
||
2585 | RELEASE_MALLOC_GLOBAL_LOCK(); |
||
2586 | if (br != CMFAIL && end != CMFAIL && br < end) { |
||
2587 | size_t ssize = end - br; |
||
2588 | if (ssize > nb + TOP_FOOT_SIZE) { |
||
2589 | tbase = br; |
||
2590 | tsize = ssize; |
||
2591 | } |
||
2592 | } |
||
2593 | } |
||
2594 | } |
||
2595 | #endif |
||
2596 | |||
2597 | if (tbase != CMFAIL) { |
||
2598 | |||
1616 | serge | 2599 | if ((m->footprint += tsize) > m->max_footprint) |
2600 | m->max_footprint = m->footprint; |
||
2601 | |||
3297 | Serge | 2602 | if (!is_initialized(m)) { /* first-time initialization */ |
1616 | serge | 2603 | if (m->least_addr == 0 || tbase < m->least_addr) |
2604 | m->least_addr = tbase; |
||
2605 | m->seg.base = tbase; |
||
2606 | m->seg.size = tsize; |
||
2607 | m->seg.sflags = mmap_flag; |
||
2608 | m->magic = mparams.magic; |
||
2609 | m->release_checks = MAX_RELEASE_CHECK_RATE; |
||
2610 | init_bins(m); |
||
2611 | |||
2612 | if (is_global(m)) |
||
2613 | init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE); |
||
2614 | else |
||
2615 | { |
||
2616 | /* Offset top by embedded malloc_state */ |
||
2617 | mchunkptr mn = next_chunk(mem2chunk(m)); |
||
2618 | init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) -TOP_FOOT_SIZE); |
||
2619 | } |
||
2620 | } |
||
3297 | Serge | 2621 | |
2622 | else { |
||
1616 | serge | 2623 | /* Try to merge with an existing segment */ |
2624 | msegmentptr sp = &m->seg; |
||
2625 | /* Only consider most recent segment if traversal suppressed */ |
||
2626 | while (sp != 0 && tbase != sp->base + sp->size) |
||
2627 | sp = (NO_SEGMENT_TRAVERSAL) ? 0 : sp->next; |
||
3297 | Serge | 2628 | if (sp != 0 && |
2629 | !is_extern_segment(sp) && |
||
1616 | serge | 2630 | (sp->sflags & USE_MMAP_BIT) == mmap_flag && |
3297 | Serge | 2631 | segment_holds(sp, m->top)) { /* append */ |
1616 | serge | 2632 | sp->size += tsize; |
2633 | init_top(m, m->top, m->topsize + tsize); |
||
2634 | } |
||
3297 | Serge | 2635 | else { |
1616 | serge | 2636 | if (tbase < m->least_addr) |
2637 | m->least_addr = tbase; |
||
2638 | sp = &m->seg; |
||
2639 | while (sp != 0 && sp->base != tbase + tsize) |
||
2640 | sp = (NO_SEGMENT_TRAVERSAL) ? 0 : sp->next; |
||
2641 | if (sp != 0 && |
||
2642 | !is_extern_segment(sp) && |
||
3297 | Serge | 2643 | (sp->sflags & USE_MMAP_BIT) == mmap_flag) { |
1616 | serge | 2644 | char* oldbase = sp->base; |
2645 | sp->base = tbase; |
||
2646 | sp->size += tsize; |
||
2647 | return prepend_alloc(m, tbase, oldbase, nb); |
||
2648 | } |
||
2649 | else |
||
2650 | add_segment(m, tbase, tsize, mmap_flag); |
||
2651 | } |
||
2652 | } |
||
2653 | |||
3297 | Serge | 2654 | if (nb < m->topsize) { /* Allocate from new or extended top space */ |
1616 | serge | 2655 | size_t rsize = m->topsize -= nb; |
2656 | mchunkptr p = m->top; |
||
2657 | mchunkptr r = m->top = chunk_plus_offset(p, nb); |
||
2658 | r->head = rsize | PINUSE_BIT; |
||
2659 | set_size_and_pinuse_of_inuse_chunk(m, p, nb); |
||
2660 | check_top_chunk(m, m->top); |
||
2661 | check_malloced_chunk(m, chunk2mem(p), nb); |
||
2662 | return chunk2mem(p); |
||
2663 | } |
||
2664 | } |
||
2665 | |||
2666 | // MALLOC_FAILURE_ACTION; |
||
2667 | return 0; |
||
2668 | } |
||
2669 | |||
2670 | /* ----------------------- system deallocation -------------------------- */ |
||
2671 | |||
2672 | /* Unmap and unlink any mmapped segments that don't contain used chunks */ |
||
3297 | Serge | 2673 | static size_t release_unused_segments(mstate m) { |
1616 | serge | 2674 | size_t released = 0; |
2675 | int nsegs = 0; |
||
2676 | msegmentptr pred = &m->seg; |
||
2677 | msegmentptr sp = pred->next; |
||
3297 | Serge | 2678 | while (sp != 0) { |
1616 | serge | 2679 | char* base = sp->base; |
2680 | size_t size = sp->size; |
||
2681 | msegmentptr next = sp->next; |
||
2682 | ++nsegs; |
||
3297 | Serge | 2683 | if (is_mmapped_segment(sp) && !is_extern_segment(sp)) { |
1616 | serge | 2684 | mchunkptr p = align_as_chunk(base); |
2685 | size_t psize = chunksize(p); |
||
2686 | /* Can unmap if first chunk holds entire segment and not pinned */ |
||
3297 | Serge | 2687 | if (!is_inuse(p) && (char*)p + psize >= base + size - TOP_FOOT_SIZE) { |
1616 | serge | 2688 | tchunkptr tp = (tchunkptr)p; |
2689 | assert(segment_holds(sp, (char*)sp)); |
||
2690 | if (p == m->dv) { |
||
2691 | m->dv = 0; |
||
2692 | m->dvsize = 0; |
||
2693 | } |
||
2694 | else { |
||
2695 | unlink_large_chunk(m, tp); |
||
2696 | } |
||
3297 | Serge | 2697 | if (CALL_MUNMAP(base, size) == 0) { |
1616 | serge | 2698 | released += size; |
2699 | m->footprint -= size; |
||
2700 | /* unlink obsoleted record */ |
||
2701 | sp = pred; |
||
2702 | sp->next = next; |
||
2703 | } |
||
2704 | else { /* back out if cannot unmap */ |
||
2705 | insert_large_chunk(m, tp, psize); |
||
2706 | } |
||
2707 | } |
||
2708 | } |
||
2709 | if (NO_SEGMENT_TRAVERSAL) /* scan only first segment */ |
||
2710 | break; |
||
2711 | pred = sp; |
||
2712 | sp = next; |
||
2713 | } |
||
2714 | /* Reset check counter */ |
||
3297 | Serge | 2715 | m->release_checks = (((size_t) nsegs > (size_t) MAX_RELEASE_CHECK_RATE)? |
2716 | (size_t) nsegs : (size_t) MAX_RELEASE_CHECK_RATE); |
||
1616 | serge | 2717 | return released; |
2718 | } |
||
2719 | |||
3297 | Serge | 2720 | static int sys_trim(mstate m, size_t pad) { |
1616 | serge | 2721 | size_t released = 0; |
2722 | ensure_initialization(); |
||
3297 | Serge | 2723 | if (pad < MAX_REQUEST && is_initialized(m)) { |
1616 | serge | 2724 | pad += TOP_FOOT_SIZE; /* ensure enough room for segment overhead */ |
2725 | |||
3297 | Serge | 2726 | if (m->topsize > pad) { |
1616 | serge | 2727 | /* Shrink top space in granularity-size units, keeping at least one */ |
2728 | size_t unit = mparams.granularity; |
||
2729 | size_t extra = ((m->topsize - pad + (unit - SIZE_T_ONE)) / unit - |
||
2730 | SIZE_T_ONE) * unit; |
||
2731 | msegmentptr sp = segment_holding(m, (char*)m->top); |
||
2732 | |||
3297 | Serge | 2733 | if (!is_extern_segment(sp)) { |
2734 | if (is_mmapped_segment(sp)) { |
||
1616 | serge | 2735 | if (HAVE_MMAP && |
2736 | sp->size >= extra && |
||
3297 | Serge | 2737 | !has_segment_link(m, sp)) { /* can't shrink if pinned */ |
1616 | serge | 2738 | size_t newsize = sp->size - extra; |
3297 | Serge | 2739 | (void)newsize; /* placate people compiling -Wunused-variable */ |
1616 | serge | 2740 | /* Prefer mremap, fall back to munmap */ |
2741 | if ((CALL_MREMAP(sp->base, sp->size, newsize, 0) != MFAIL) || |
||
3297 | Serge | 2742 | (CALL_MUNMAP(sp->base + newsize, extra) == 0)) { |
2743 | released = extra; |
||
2744 | } |
||
2745 | } |
||
2746 | } |
||
2747 | else if (HAVE_MORECORE) { |
||
2748 | if (extra >= HALF_MAX_SIZE_T) /* Avoid wrapping negative */ |
||
2749 | extra = (HALF_MAX_SIZE_T) + SIZE_T_ONE - unit; |
||
2750 | ACQUIRE_MALLOC_GLOBAL_LOCK(); |
||
1616 | serge | 2751 | { |
3297 | Serge | 2752 | /* Make sure end of memory is where we last set it. */ |
2753 | char* old_br = (char*)(CALL_MORECORE(0)); |
||
2754 | if (old_br == sp->base + sp->size) { |
||
2755 | char* rel_br = (char*)(CALL_MORECORE(-extra)); |
||
2756 | char* new_br = (char*)(CALL_MORECORE(0)); |
||
2757 | if (rel_br != CMFAIL && new_br < old_br) |
||
2758 | released = old_br - new_br; |
||
1616 | serge | 2759 | } |
2760 | } |
||
3297 | Serge | 2761 | RELEASE_MALLOC_GLOBAL_LOCK(); |
1616 | serge | 2762 | } |
2763 | } |
||
2764 | |||
3297 | Serge | 2765 | if (released != 0) { |
1616 | serge | 2766 | sp->size -= released; |
2767 | m->footprint -= released; |
||
2768 | init_top(m, m->top, m->topsize - released); |
||
2769 | check_top_chunk(m, m->top); |
||
2770 | } |
||
2771 | } |
||
2772 | |||
2773 | /* Unmap any unused mmapped segments */ |
||
2774 | if (HAVE_MMAP) |
||
2775 | released += release_unused_segments(m); |
||
2776 | |||
2777 | /* On failure, disable autotrim to avoid repeated failed future calls */ |
||
2778 | if (released == 0 && m->topsize > m->trim_check) |
||
2779 | m->trim_check = MAX_SIZE_T; |
||
2780 | } |
||
2781 | |||
2782 | return (released != 0)? 1 : 0; |
||
2783 | } |
||
2784 | |||
3297 | Serge | 2785 | /* Consolidate and bin a chunk. Differs from exported versions |
2786 | of free mainly in that the chunk need not be marked as inuse. |
||
2787 | */ |
||
2788 | static void dispose_chunk(mstate m, mchunkptr p, size_t psize) { |
||
2789 | mchunkptr next = chunk_plus_offset(p, psize); |
||
2790 | if (!pinuse(p)) { |
||
2791 | mchunkptr prev; |
||
2792 | size_t prevsize = p->prev_foot; |
||
2793 | if (is_mmapped(p)) { |
||
2794 | psize += prevsize + MMAP_FOOT_PAD; |
||
2795 | if (CALL_MUNMAP((char*)p - prevsize, psize) == 0) |
||
2796 | m->footprint -= psize; |
||
2797 | return; |
||
2798 | } |
||
2799 | prev = chunk_minus_offset(p, prevsize); |
||
2800 | psize += prevsize; |
||
2801 | p = prev; |
||
2802 | if (RTCHECK(ok_address(m, prev))) { /* consolidate backward */ |
||
2803 | if (p != m->dv) { |
||
2804 | unlink_chunk(m, p, prevsize); |
||
2805 | } |
||
2806 | else if ((next->head & INUSE_BITS) == INUSE_BITS) { |
||
2807 | m->dvsize = psize; |
||
2808 | set_free_with_pinuse(p, psize, next); |
||
2809 | return; |
||
2810 | } |
||
2811 | } |
||
2812 | else { |
||
2813 | CORRUPTION_ERROR_ACTION(m); |
||
2814 | return; |
||
2815 | } |
||
2816 | } |
||
2817 | if (RTCHECK(ok_address(m, next))) { |
||
2818 | if (!cinuse(next)) { /* consolidate forward */ |
||
2819 | if (next == m->top) { |
||
2820 | size_t tsize = m->topsize += psize; |
||
2821 | m->top = p; |
||
2822 | p->head = tsize | PINUSE_BIT; |
||
2823 | if (p == m->dv) { |
||
2824 | m->dv = 0; |
||
2825 | m->dvsize = 0; |
||
2826 | } |
||
2827 | return; |
||
2828 | } |
||
2829 | else if (next == m->dv) { |
||
2830 | size_t dsize = m->dvsize += psize; |
||
2831 | m->dv = p; |
||
2832 | set_size_and_pinuse_of_free_chunk(p, dsize); |
||
2833 | return; |
||
2834 | } |
||
2835 | else { |
||
2836 | size_t nsize = chunksize(next); |
||
2837 | psize += nsize; |
||
2838 | unlink_chunk(m, next, nsize); |
||
2839 | set_size_and_pinuse_of_free_chunk(p, psize); |
||
2840 | if (p == m->dv) { |
||
2841 | m->dvsize = psize; |
||
2842 | return; |
||
2843 | } |
||
2844 | } |
||
2845 | } |
||
2846 | else { |
||
2847 | set_free_with_pinuse(p, psize, next); |
||
2848 | } |
||
2849 | insert_chunk(m, p, psize); |
||
2850 | } |
||
2851 | else { |
||
2852 | CORRUPTION_ERROR_ACTION(m); |
||
2853 | } |
||
2854 | } |
||
1616 | serge | 2855 | |
3297 | Serge | 2856 | /* ---------------------------- malloc --------------------------- */ |
1616 | serge | 2857 | |
2858 | /* allocate a large request from the best fitting chunk in a treebin */ |
||
2859 | static void* tmalloc_large(mstate m, size_t nb) { |
||
2860 | tchunkptr v = 0; |
||
2861 | size_t rsize = -nb; /* Unsigned negation */ |
||
2862 | tchunkptr t; |
||
2863 | bindex_t idx; |
||
2864 | compute_tree_index(nb, idx); |
||
2865 | if ((t = *treebin_at(m, idx)) != 0) { |
||
2866 | /* Traverse tree for this bin looking for node with size == nb */ |
||
2867 | size_t sizebits = nb << leftshift_for_tree_index(idx); |
||
2868 | tchunkptr rst = 0; /* The deepest untaken right subtree */ |
||
2869 | for (;;) { |
||
2870 | tchunkptr rt; |
||
2871 | size_t trem = chunksize(t) - nb; |
||
2872 | if (trem < rsize) { |
||
2873 | v = t; |
||
2874 | if ((rsize = trem) == 0) |
||
2875 | break; |
||
2876 | } |
||
2877 | rt = t->child[1]; |
||
2878 | t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1]; |
||
2879 | if (rt != 0 && rt != t) |
||
2880 | rst = rt; |
||
2881 | if (t == 0) { |
||
2882 | t = rst; /* set t to least subtree holding sizes > nb */ |
||
2883 | break; |
||
2884 | } |
||
2885 | sizebits <<= 1; |
||
2886 | } |
||
2887 | } |
||
2888 | if (t == 0 && v == 0) { /* set t to root of next non-empty treebin */ |
||
2889 | binmap_t leftbits = left_bits(idx2bit(idx)) & m->treemap; |
||
2890 | if (leftbits != 0) { |
||
2891 | bindex_t i; |
||
2892 | binmap_t leastbit = least_bit(leftbits); |
||
2893 | compute_bit2idx(leastbit, i); |
||
2894 | t = *treebin_at(m, i); |
||
2895 | } |
||
2896 | } |
||
2897 | |||
2898 | while (t != 0) { /* find smallest of tree or subtree */ |
||
2899 | size_t trem = chunksize(t) - nb; |
||
2900 | if (trem < rsize) { |
||
2901 | rsize = trem; |
||
2902 | v = t; |
||
2903 | } |
||
2904 | t = leftmost_child(t); |
||
2905 | } |
||
2906 | |||
2907 | /* If dv is a better fit, return 0 so malloc will use it */ |
||
2908 | if (v != 0 && rsize < (size_t)(m->dvsize - nb)) { |
||
2909 | if (RTCHECK(ok_address(m, v))) { /* split */ |
||
2910 | mchunkptr r = chunk_plus_offset(v, nb); |
||
2911 | assert(chunksize(v) == rsize + nb); |
||
2912 | if (RTCHECK(ok_next(v, r))) { |
||
2913 | unlink_large_chunk(m, v); |
||
2914 | if (rsize < MIN_CHUNK_SIZE) |
||
2915 | set_inuse_and_pinuse(m, v, (rsize + nb)); |
||
2916 | else { |
||
2917 | set_size_and_pinuse_of_inuse_chunk(m, v, nb); |
||
2918 | set_size_and_pinuse_of_free_chunk(r, rsize); |
||
2919 | insert_chunk(m, r, rsize); |
||
2920 | } |
||
2921 | return chunk2mem(v); |
||
2922 | } |
||
2923 | } |
||
2924 | CORRUPTION_ERROR_ACTION(m); |
||
2925 | } |
||
2926 | return 0; |
||
2927 | } |
||
2928 | |||
2929 | /* allocate a small request from the best fitting chunk in a treebin */ |
||
3297 | Serge | 2930 | static void* tmalloc_small(mstate m, size_t nb) { |
1616 | serge | 2931 | tchunkptr t, v; |
2932 | size_t rsize; |
||
2933 | bindex_t i; |
||
2934 | binmap_t leastbit = least_bit(m->treemap); |
||
2935 | compute_bit2idx(leastbit, i); |
||
2936 | v = t = *treebin_at(m, i); |
||
2937 | rsize = chunksize(t) - nb; |
||
2938 | |||
2939 | while ((t = leftmost_child(t)) != 0) { |
||
2940 | size_t trem = chunksize(t) - nb; |
||
2941 | if (trem < rsize) { |
||
2942 | rsize = trem; |
||
2943 | v = t; |
||
2944 | } |
||
2945 | } |
||
2946 | |||
2947 | if (RTCHECK(ok_address(m, v))) { |
||
2948 | mchunkptr r = chunk_plus_offset(v, nb); |
||
2949 | assert(chunksize(v) == rsize + nb); |
||
2950 | if (RTCHECK(ok_next(v, r))) { |
||
2951 | unlink_large_chunk(m, v); |
||
2952 | if (rsize < MIN_CHUNK_SIZE) |
||
2953 | set_inuse_and_pinuse(m, v, (rsize + nb)); |
||
2954 | else { |
||
2955 | set_size_and_pinuse_of_inuse_chunk(m, v, nb); |
||
2956 | set_size_and_pinuse_of_free_chunk(r, rsize); |
||
2957 | replace_dv(m, r, rsize); |
||
2958 | } |
||
2959 | return chunk2mem(v); |
||
2960 | } |
||
2961 | } |
||
2962 | |||
2963 | CORRUPTION_ERROR_ACTION(m); |
||
2964 | return 0; |
||
2965 | } |
||
2966 | |||
2967 | |||
2968 | void* malloc(size_t bytes) |
||
2969 | { |
||
2970 | /* |
||
2971 | Basic algorithm: |
||
2972 | If a small request (< 256 bytes minus per-chunk overhead): |
||
2973 | 1. If one exists, use a remainderless chunk in associated smallbin. |
||
2974 | (Remainderless means that there are too few excess bytes to |
||
2975 | represent as a chunk.) |
||
2976 | 2. If it is big enough, use the dv chunk, which is normally the |
||
2977 | chunk adjacent to the one used for the most recent small request. |
||
2978 | 3. If one exists, split the smallest available chunk in a bin, |
||
2979 | saving remainder in dv. |
||
2980 | 4. If it is big enough, use the top chunk. |
||
2981 | 5. If available, get memory from system and use it |
||
2982 | Otherwise, for a large request: |
||
2983 | 1. Find the smallest available binned chunk that fits, and use it |
||
2984 | if it is better fitting than dv chunk, splitting if necessary. |
||
2985 | 2. If better fitting than any binned chunk, use the dv chunk. |
||
2986 | 3. If it is big enough, use the top chunk. |
||
2987 | 4. If request size >= mmap threshold, try to directly mmap this chunk. |
||
2988 | 5. If available, get memory from system and use it |
||
2989 | |||
2990 | The ugly goto's here ensure that postaction occurs along all paths. |
||
2991 | */ |
||
2992 | |||
2993 | ensure_initialization(); /* initialize in sys_alloc if not using locks */ |
||
2994 | |||
2995 | PREACTION(gm); |
||
2996 | { |
||
2997 | void* mem; |
||
2998 | size_t nb; |
||
3297 | Serge | 2999 | if (bytes <= MAX_SMALL_REQUEST) { |
1616 | serge | 3000 | bindex_t idx; |
3001 | binmap_t smallbits; |
||
3002 | nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes); |
||
3003 | idx = small_index(nb); |
||
3004 | smallbits = gm->smallmap >> idx; |
||
3005 | |||
3297 | Serge | 3006 | if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */ |
1616 | serge | 3007 | mchunkptr b, p; |
3008 | idx += ~smallbits & 1; /* Uses next bin if idx empty */ |
||
3009 | b = smallbin_at(gm, idx); |
||
3010 | p = b->fd; |
||
3011 | assert(chunksize(p) == small_index2size(idx)); |
||
3012 | unlink_first_small_chunk(gm, b, p, idx); |
||
3013 | set_inuse_and_pinuse(gm, p, small_index2size(idx)); |
||
3014 | mem = chunk2mem(p); |
||
3015 | check_malloced_chunk(gm, mem, nb); |
||
3016 | goto postaction; |
||
3017 | } |
||
3297 | Serge | 3018 | |
3019 | else if (nb > gm->dvsize) { |
||
3020 | if (smallbits != 0) { /* Use chunk in next nonempty smallbin */ |
||
1616 | serge | 3021 | mchunkptr b, p, r; |
3022 | size_t rsize; |
||
3023 | bindex_t i; |
||
3024 | binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx)); |
||
3025 | binmap_t leastbit = least_bit(leftbits); |
||
3026 | compute_bit2idx(leastbit, i); |
||
3027 | b = smallbin_at(gm, i); |
||
3028 | p = b->fd; |
||
3029 | assert(chunksize(p) == small_index2size(i)); |
||
3030 | unlink_first_small_chunk(gm, b, p, i); |
||
3031 | rsize = small_index2size(i) - nb; |
||
3032 | /* Fit here cannot be remainderless if 4byte sizes */ |
||
3033 | if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE) |
||
3034 | set_inuse_and_pinuse(gm, p, small_index2size(i)); |
||
3297 | Serge | 3035 | else { |
1616 | serge | 3036 | set_size_and_pinuse_of_inuse_chunk(gm, p, nb); |
3037 | r = chunk_plus_offset(p, nb); |
||
3038 | set_size_and_pinuse_of_free_chunk(r, rsize); |
||
3039 | replace_dv(gm, r, rsize); |
||
3040 | } |
||
3041 | mem = chunk2mem(p); |
||
3042 | check_malloced_chunk(gm, mem, nb); |
||
3043 | goto postaction; |
||
3044 | } |
||
3297 | Serge | 3045 | |
3046 | else if (gm->treemap != 0 && (mem = tmalloc_small(gm, nb)) != 0) { |
||
1616 | serge | 3047 | check_malloced_chunk(gm, mem, nb); |
3048 | goto postaction; |
||
3049 | } |
||
3050 | } |
||
3051 | } |
||
3052 | else if (bytes >= MAX_REQUEST) |
||
3053 | nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */ |
||
3297 | Serge | 3054 | else { |
1616 | serge | 3055 | nb = pad_request(bytes); |
3297 | Serge | 3056 | if (gm->treemap != 0 && (mem = tmalloc_large(gm, nb)) != 0) { |
1616 | serge | 3057 | check_malloced_chunk(gm, mem, nb); |
3058 | goto postaction; |
||
3059 | } |
||
3060 | } |
||
3061 | |||
3062 | if (nb <= gm->dvsize) { |
||
3063 | size_t rsize = gm->dvsize - nb; |
||
3064 | mchunkptr p = gm->dv; |
||
3065 | if (rsize >= MIN_CHUNK_SIZE) { /* split dv */ |
||
3066 | mchunkptr r = gm->dv = chunk_plus_offset(p, nb); |
||
3067 | gm->dvsize = rsize; |
||
3068 | set_size_and_pinuse_of_free_chunk(r, rsize); |
||
3069 | set_size_and_pinuse_of_inuse_chunk(gm, p, nb); |
||
3070 | } |
||
3071 | else { /* exhaust dv */ |
||
3072 | size_t dvs = gm->dvsize; |
||
3073 | gm->dvsize = 0; |
||
3074 | gm->dv = 0; |
||
3075 | set_inuse_and_pinuse(gm, p, dvs); |
||
3076 | } |
||
3077 | mem = chunk2mem(p); |
||
3078 | check_malloced_chunk(gm, mem, nb); |
||
3079 | goto postaction; |
||
3080 | } |
||
3297 | Serge | 3081 | |
1616 | serge | 3082 | else if (nb < gm->topsize) { /* Split top */ |
3083 | size_t rsize = gm->topsize -= nb; |
||
3084 | mchunkptr p = gm->top; |
||
3085 | mchunkptr r = gm->top = chunk_plus_offset(p, nb); |
||
3086 | r->head = rsize | PINUSE_BIT; |
||
3087 | set_size_and_pinuse_of_inuse_chunk(gm, p, nb); |
||
3088 | mem = chunk2mem(p); |
||
3089 | check_top_chunk(gm, gm->top); |
||
3090 | check_malloced_chunk(gm, mem, nb); |
||
3091 | goto postaction; |
||
3092 | } |
||
3093 | |||
3094 | mem = sys_alloc(gm, nb); |
||
3095 | |||
3096 | postaction: |
||
3097 | POSTACTION(gm); |
||
3297 | Serge | 3098 | // printf("%s %p %d\n", __FUNCTION__, mem, bytes); |
1616 | serge | 3099 | return mem; |
3100 | } |
||
3297 | Serge | 3101 | // FAIL(); |
1616 | serge | 3102 | return 0; |
3103 | } |
||
3104 | |||
3297 | Serge | 3105 | /* ---------------------------- free --------------------------- */ |
1616 | serge | 3106 | |
3391 | Serge | 3107 | void free(void* mem){ |
1616 | serge | 3108 | /* |
3109 | Consolidate freed chunks with preceeding or succeeding bordering |
||
3110 | free chunks, if they exist, and then place in a bin. Intermixed |
||
3111 | with special cases for top, dv, mmapped chunks, and usage errors. |
||
3112 | */ |
||
3113 | |||
3297 | Serge | 3114 | // dbgprintf("%s %p\n", __FUNCTION__, mem); |
3115 | |||
3116 | if (mem != 0) { |
||
1616 | serge | 3117 | mchunkptr p = mem2chunk(mem); |
3297 | Serge | 3118 | #if FOOTERS |
3119 | mstate fm = get_mstate_for(p); |
||
3120 | if (!ok_magic(fm)) { |
||
3121 | USAGE_ERROR_ACTION(fm, p); |
||
3122 | return; |
||
3123 | } |
||
3124 | #else /* FOOTERS */ |
||
1616 | serge | 3125 | #define fm gm |
3297 | Serge | 3126 | #endif /* FOOTERS */ |
1616 | serge | 3127 | PREACTION(fm); |
3128 | { |
||
3129 | check_inuse_chunk(fm, p); |
||
3297 | Serge | 3130 | if (RTCHECK(ok_address(fm, p) && ok_inuse(p))) { |
1616 | serge | 3131 | size_t psize = chunksize(p); |
3132 | mchunkptr next = chunk_plus_offset(p, psize); |
||
3297 | Serge | 3133 | if (!pinuse(p)) { |
1616 | serge | 3134 | size_t prevsize = p->prev_foot; |
3297 | Serge | 3135 | if (is_mmapped(p)) { |
1616 | serge | 3136 | psize += prevsize + MMAP_FOOT_PAD; |
3137 | if (CALL_MUNMAP((char*)p - prevsize, psize) == 0) |
||
3138 | fm->footprint -= psize; |
||
3139 | goto postaction; |
||
3140 | } |
||
3297 | Serge | 3141 | else { |
1616 | serge | 3142 | mchunkptr prev = chunk_minus_offset(p, prevsize); |
3143 | psize += prevsize; |
||
3144 | p = prev; |
||
3297 | Serge | 3145 | if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */ |
3146 | if (p != fm->dv) { |
||
1616 | serge | 3147 | unlink_chunk(fm, p, prevsize); |
3148 | } |
||
3297 | Serge | 3149 | else if ((next->head & INUSE_BITS) == INUSE_BITS) { |
1616 | serge | 3150 | fm->dvsize = psize; |
3151 | set_free_with_pinuse(p, psize, next); |
||
3152 | goto postaction; |
||
3153 | } |
||
3154 | } |
||
3155 | else |
||
3156 | goto erroraction; |
||
3157 | } |
||
3158 | } |
||
3159 | |||
3297 | Serge | 3160 | if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) { |
3161 | if (!cinuse(next)) { /* consolidate forward */ |
||
3162 | if (next == fm->top) { |
||
1616 | serge | 3163 | size_t tsize = fm->topsize += psize; |
3164 | fm->top = p; |
||
3165 | p->head = tsize | PINUSE_BIT; |
||
3297 | Serge | 3166 | if (p == fm->dv) { |
1616 | serge | 3167 | fm->dv = 0; |
3168 | fm->dvsize = 0; |
||
3169 | } |
||
3170 | if (should_trim(fm, tsize)) |
||
3171 | sys_trim(fm, 0); |
||
3172 | goto postaction; |
||
3173 | } |
||
3297 | Serge | 3174 | else if (next == fm->dv) { |
1616 | serge | 3175 | size_t dsize = fm->dvsize += psize; |
3176 | fm->dv = p; |
||
3177 | set_size_and_pinuse_of_free_chunk(p, dsize); |
||
3178 | goto postaction; |
||
3179 | } |
||
3297 | Serge | 3180 | else { |
1616 | serge | 3181 | size_t nsize = chunksize(next); |
3182 | psize += nsize; |
||
3183 | unlink_chunk(fm, next, nsize); |
||
3184 | set_size_and_pinuse_of_free_chunk(p, psize); |
||
3297 | Serge | 3185 | if (p == fm->dv) { |
1616 | serge | 3186 | fm->dvsize = psize; |
3187 | goto postaction; |
||
3188 | } |
||
3189 | } |
||
3190 | } |
||
3191 | else |
||
3192 | set_free_with_pinuse(p, psize, next); |
||
3193 | |||
3297 | Serge | 3194 | if (is_small(psize)) { |
1616 | serge | 3195 | insert_small_chunk(fm, p, psize); |
3196 | check_free_chunk(fm, p); |
||
3197 | } |
||
3297 | Serge | 3198 | else { |
1616 | serge | 3199 | tchunkptr tp = (tchunkptr)p; |
3200 | insert_large_chunk(fm, tp, psize); |
||
3201 | check_free_chunk(fm, p); |
||
3202 | if (--fm->release_checks == 0) |
||
3203 | release_unused_segments(fm); |
||
3204 | } |
||
3205 | goto postaction; |
||
3206 | } |
||
3207 | } |
||
3208 | erroraction: |
||
3209 | USAGE_ERROR_ACTION(fm, p); |
||
3210 | postaction: |
||
3211 | POSTACTION(fm); |
||
3212 | } |
||
3213 | } |
||
3297 | Serge | 3214 | |
3215 | // LEAVE(); |
||
3216 | |||
3217 | #if !FOOTERS |
||
1616 | serge | 3218 | #undef fm |
3297 | Serge | 3219 | #endif /* FOOTERS */ |
1616 | serge | 3220 | } |
3221 | |||
3391 | Serge | 3222 | void* calloc(size_t n_elements, size_t elem_size) { |
3223 | void* mem; |
||
3224 | size_t req = 0; |
||
3225 | if (n_elements != 0) { |
||
3226 | req = n_elements * elem_size; |
||
3227 | if (((n_elements | elem_size) & ~(size_t)0xffff) && |
||
3228 | (req / n_elements != elem_size)) |
||
3229 | req = MAX_SIZE_T; /* force downstream failure on overflow */ |
||
3230 | } |
||
3231 | mem = malloc(req); |
||
3232 | if (mem != 0 && calloc_must_clear(mem2chunk(mem))) |
||
3233 | memset(mem, 0, req); |
||
3234 | return mem; |
||
3235 | } |
||
1616 | serge | 3236 | |
3391 | Serge | 3237 | /* ------------ Internal support for realloc, memalign, etc -------------- */ |
3238 | |||
3239 | /* Try to realloc; only in-place unless can_move true */ |
||
3240 | static mchunkptr try_realloc_chunk(mstate m, mchunkptr p, size_t nb, |
||
3241 | int can_move) { |
||
3242 | mchunkptr newp = 0; |
||
3243 | size_t oldsize = chunksize(p); |
||
3244 | mchunkptr next = chunk_plus_offset(p, oldsize); |
||
3245 | if (RTCHECK(ok_address(m, p) && ok_inuse(p) && |
||
3246 | ok_next(p, next) && ok_pinuse(next))) { |
||
3247 | if (is_mmapped(p)) { |
||
3248 | newp = mmap_resize(m, p, nb, can_move); |
||
3249 | } |
||
3250 | else if (oldsize >= nb) { /* already big enough */ |
||
3251 | size_t rsize = oldsize - nb; |
||
3252 | if (rsize >= MIN_CHUNK_SIZE) { /* split off remainder */ |
||
3253 | mchunkptr r = chunk_plus_offset(p, nb); |
||
3254 | set_inuse(m, p, nb); |
||
3255 | set_inuse(m, r, rsize); |
||
3256 | dispose_chunk(m, r, rsize); |
||
3257 | } |
||
3258 | newp = p; |
||
3259 | } |
||
3260 | else if (next == m->top) { /* extend into top */ |
||
3261 | if (oldsize + m->topsize > nb) { |
||
3262 | size_t newsize = oldsize + m->topsize; |
||
3263 | size_t newtopsize = newsize - nb; |
||
3264 | mchunkptr newtop = chunk_plus_offset(p, nb); |
||
3265 | set_inuse(m, p, nb); |
||
3266 | newtop->head = newtopsize |PINUSE_BIT; |
||
3267 | m->top = newtop; |
||
3268 | m->topsize = newtopsize; |
||
3269 | newp = p; |
||
3270 | } |
||
3271 | } |
||
3272 | else if (next == m->dv) { /* extend into dv */ |
||
3273 | size_t dvs = m->dvsize; |
||
3274 | if (oldsize + dvs >= nb) { |
||
3275 | size_t dsize = oldsize + dvs - nb; |
||
3276 | if (dsize >= MIN_CHUNK_SIZE) { |
||
3277 | mchunkptr r = chunk_plus_offset(p, nb); |
||
3278 | mchunkptr n = chunk_plus_offset(r, dsize); |
||
3279 | set_inuse(m, p, nb); |
||
3280 | set_size_and_pinuse_of_free_chunk(r, dsize); |
||
3281 | clear_pinuse(n); |
||
3282 | m->dvsize = dsize; |
||
3283 | m->dv = r; |
||
3284 | } |
||
3285 | else { /* exhaust dv */ |
||
3286 | size_t newsize = oldsize + dvs; |
||
3287 | set_inuse(m, p, newsize); |
||
3288 | m->dvsize = 0; |
||
3289 | m->dv = 0; |
||
3290 | } |
||
3291 | newp = p; |
||
3292 | } |
||
3293 | } |
||
3294 | else if (!cinuse(next)) { /* extend into next free chunk */ |
||
3295 | size_t nextsize = chunksize(next); |
||
3296 | if (oldsize + nextsize >= nb) { |
||
3297 | size_t rsize = oldsize + nextsize - nb; |
||
3298 | unlink_chunk(m, next, nextsize); |
||
3299 | if (rsize < MIN_CHUNK_SIZE) { |
||
3300 | size_t newsize = oldsize + nextsize; |
||
3301 | set_inuse(m, p, newsize); |
||
3302 | } |
||
3303 | else { |
||
3304 | mchunkptr r = chunk_plus_offset(p, nb); |
||
3305 | set_inuse(m, p, nb); |
||
3306 | set_inuse(m, r, rsize); |
||
3307 | dispose_chunk(m, r, rsize); |
||
3308 | } |
||
3309 | newp = p; |
||
3310 | } |
||
3311 | } |
||
3312 | } |
||
3313 | else { |
||
3314 | USAGE_ERROR_ACTION(m, chunk2mem(p)); |
||
3315 | } |
||
3316 | return newp; |
||
3317 | } |
||
3318 | |||
3319 | |||
3320 | void* realloc(void* oldmem, size_t bytes) { |
||
3321 | void* mem = 0; |
||
3322 | if (oldmem == 0) { |
||
3323 | mem = malloc(bytes); |
||
3324 | } |
||
3325 | else if (bytes >= MAX_REQUEST) { |
||
3326 | // MALLOC_FAILURE_ACTION; |
||
3327 | } |
||
3328 | #ifdef REALLOC_ZERO_BYTES_FREES |
||
3329 | else if (bytes == 0) { |
||
3330 | free(oldmem); |
||
3331 | } |
||
3332 | #endif /* REALLOC_ZERO_BYTES_FREES */ |
||
3333 | else { |
||
3334 | size_t nb = request2size(bytes); |
||
3335 | mchunkptr oldp = mem2chunk(oldmem); |
||
3336 | #if ! FOOTERS |
||
3337 | mstate m = gm; |
||
3338 | #else /* FOOTERS */ |
||
3339 | mstate m = get_mstate_for(oldp); |
||
3340 | if (!ok_magic(m)) { |
||
3341 | USAGE_ERROR_ACTION(m, oldmem); |
||
3342 | return 0; |
||
3343 | } |
||
3344 | #endif /* FOOTERS */ |
||
3345 | PREACTION(m); { |
||
3346 | mchunkptr newp = try_realloc_chunk(m, oldp, nb, 1); |
||
3347 | POSTACTION(m); |
||
3348 | if (newp != 0) { |
||
3349 | check_inuse_chunk(m, newp); |
||
3350 | mem = chunk2mem(newp); |
||
3351 | } |
||
3352 | else { |
||
3353 | mem = internal_malloc(m, bytes); |
||
3354 | if (mem != 0) { |
||
3355 | size_t oc = chunksize(oldp) - overhead_for(oldp); |
||
3356 | memcpy(mem, oldmem, (oc < bytes)? oc : bytes); |
||
3357 | internal_free(m, oldmem); |
||
3358 | } |
||
3359 | } |
||
3360 | } |
||
3361 | } |
||
3362 | return mem; |
||
3363 | }>>>=>>><>>=>>>>>>>=><=>>><>>>>>>>>>>>>=>>=>=>>>>>><>=>>=>=><=>><>=>=>>>=><=>><>><>><>>>>>1)) |
||
3364 | |||
3365 | |||
3366 | |||
3367 |