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5191 | serge | 1 | /* Yet Another Try at encapsulating bfd object files in coff. |
2 | Copyright 1988, 1989, 1991, 2010 Free Software Foundation, Inc. |
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3 | Written by Pace Willisson 12/9/88 |
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4 | |||
5 | This file is obsolete. It needs to be converted to just define a bunch |
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6 | of stuff that BFD can use to do coff-encapsulated files. --gnu@cygnus.com |
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7 | |||
8 | This program is free software; you can redistribute it and/or modify |
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9 | it under the terms of the GNU General Public License as published by |
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10 | the Free Software Foundation; either version 3 of the License, or |
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11 | (at your option) any later version. |
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12 | |||
13 | This program is distributed in the hope that it will be useful, |
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14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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16 | GNU General Public License for more details. |
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17 | |||
18 | You should have received a copy of the GNU General Public License |
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19 | along with this program; if not, write to the Free Software |
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20 | Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
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21 | MA 02110-1301, USA. */ |
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22 | |||
23 | /* |
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24 | * We only use the coff headers to tell the kernel |
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25 | * how to exec the file. Therefore, the only fields that need to |
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26 | * be filled in are the scnptr and vaddr for the text and data |
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27 | * sections, and the vaddr for the bss. As far as coff is concerned, |
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28 | * there is no symbol table, relocation, or line numbers. |
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29 | * |
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30 | * A normal bsd header (struct exec) is placed after the coff headers, |
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31 | * and before the real text. I defined a the new fields 'a_machtype' |
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32 | * and a_flags. If a_machtype is M_386, and a_flags & A_ENCAP is |
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33 | * true, then the bsd header is preceeded by a coff header. Macros |
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34 | * like N_TXTOFF and N_TXTADDR use this field to find the bsd header. |
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35 | * |
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36 | * The only problem is to track down the bsd exec header. The |
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37 | * macros HEADER_OFFSET, etc do this. |
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38 | */ |
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39 | |||
40 | #define N_FLAGS_COFF_ENCAPSULATE 0x20 /* coff header precedes bsd header */ |
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41 | |||
42 | /* Describe the COFF header used for encapsulation. */ |
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43 | |||
44 | struct coffheader |
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45 | { |
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46 | /* filehdr */ |
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47 | unsigned short f_magic; |
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48 | unsigned short f_nscns; |
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49 | long f_timdat; |
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50 | long f_symptr; |
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51 | long f_nsyms; |
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52 | unsigned short f_opthdr; |
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53 | unsigned short f_flags; |
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54 | /* aouthdr */ |
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55 | short magic; |
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56 | short vstamp; |
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57 | long tsize; |
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58 | long dsize; |
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59 | long bsize; |
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60 | long entry; |
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61 | long text_start; |
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62 | long data_start; |
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63 | struct coffscn |
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64 | { |
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65 | char s_name[8]; |
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66 | long s_paddr; |
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67 | long s_vaddr; |
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68 | long s_size; |
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69 | long s_scnptr; |
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70 | long s_relptr; |
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71 | long s_lnnoptr; |
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72 | unsigned short s_nreloc; |
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73 | unsigned short s_nlnno; |
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74 | long s_flags; |
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75 | } scns[3]; |
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76 | }; |
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77 | |||
78 | /* Describe some of the parameters of the encapsulation, |
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79 | including how to find the encapsulated BSD header. */ |
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80 | |||
81 | /* FIXME, this is dumb. The same tools can't handle a.outs for different |
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82 | architectures, just because COFF_MAGIC is different; so you need a |
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83 | separate GNU nm for every architecture!!? Unfortunately, it needs to |
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84 | be this way, since the COFF_MAGIC value is determined by the kernel |
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85 | we're trying to fool here. */ |
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86 | |||
87 | #define COFF_MAGIC_I386 0514 /* I386MAGIC */ |
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88 | #define COFF_MAGIC_M68K 0520 /* MC68MAGIC */ |
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89 | |||
90 | #ifdef COFF_MAGIC |
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91 | short __header_offset_temp; |
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92 | #define HEADER_OFFSET(f) \ |
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93 | (__header_offset_temp = 0, \ |
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94 | fread ((char *)&__header_offset_temp, sizeof (short), 1, (f)), \ |
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95 | fseek ((f), -sizeof (short), 1), \ |
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96 | __header_offset_temp==COFF_MAGIC ? sizeof(struct coffheader) : 0) |
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97 | #else |
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98 | #define HEADER_OFFSET(f) 0 |
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99 | #endif |
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100 | |||
101 | #define HEADER_SEEK(f) (fseek ((f), HEADER_OFFSET((f)), 1)) |
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102 | |||
103 | /* Describe the characteristics of the BSD header |
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104 | that appears inside the encapsulation. */ |
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105 | |||
106 | /* Encapsulated coff files that are linked ZMAGIC have a text segment |
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107 | offset just past the header (and a matching TXTADDR), excluding |
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108 | the headers from the text segment proper but keeping the physical |
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109 | layout and the virtual memory layout page-aligned. |
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110 | |||
111 | Non-encapsulated a.out files that are linked ZMAGIC have a text |
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112 | segment that starts at 0 and an N_TXTADR similarly offset to 0. |
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113 | They too are page-aligned with each other, but they include the |
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114 | a.out header as part of the text. |
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115 | |||
116 | The _N_HDROFF gets sizeof struct exec added to it, so we have |
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117 | to compensate here. See |
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118 | |||
119 | #undef _N_HDROFF |
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120 | #undef N_TXTADDR |
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121 | #undef N_DATADDR |
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122 | |||
123 | #define _N_HDROFF(x) ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \ |
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124 | sizeof (struct coffheader) : 0) |
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125 | |||
126 | /* Address of text segment in memory after it is loaded. */ |
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127 | #define N_TXTADDR(x) \ |
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128 | ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \ |
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129 | sizeof (struct coffheader) + sizeof (struct exec) : 0) |
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130 | #define SEGMENT_SIZE 0x400000 |
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131 | |||
132 | #define N_DATADDR(x) \ |
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133 | ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \ |
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134 | (SEGMENT_SIZE + ((N_TXTADDR(x)+(x).a_text-1) & ~(SEGMENT_SIZE-1))) : \ |
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135 | (N_TXTADDR(x)+(x).a_text)) |