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2119 | clevermous | 1 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
2 | ;; ;; |
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3 | ;; Copyright (C) KolibriOS team 2011. All rights reserved. ;; |
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4 | ;; Distributed under terms of the GNU General Public License ;; |
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5 | ;; ;; |
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6 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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7 | |||
2140 | clevermous | 8 | $Revision: 2257 $ |
9 | |||
2119 | clevermous | 10 | ; ============================================================================= |
11 | ; ================================= Constants ================================= |
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12 | ; ============================================================================= |
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13 | ; Error codes for callback functions. |
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2257 | killerkiri | 14 | DISK_STATUS_OK = 0 ; success |
2119 | clevermous | 15 | DISK_STATUS_GENERAL_ERROR = -1; if no other code is suitable |
16 | DISK_STATUS_INVALID_CALL = 1 ; invalid input parameters |
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2257 | killerkiri | 17 | DISK_STATUS_NO_MEDIA = 2 ; no media present |
2119 | clevermous | 18 | DISK_STATUS_END_OF_MEDIA = 3 ; end of media while reading/writing data |
19 | ; Driver flags. Represent bits in DISK.DriverFlags. |
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20 | DISK_NO_INSERT_NOTIFICATION = 1 |
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21 | ; Media flags. Represent bits in DISKMEDIAINFO.Flags. |
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22 | DISK_MEDIA_READONLY = 1 |
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23 | |||
2257 | killerkiri | 24 | ; If too many partitions are detected,there is probably an error on the disk. |
2119 | clevermous | 25 | ; 256 partitions should be enough for any reasonable use. |
2257 | killerkiri | 26 | ; Also, the same number is limiting the number of MBRs to process; if |
27 | ; too many MBRs are visible,there probably is a loop in the MBR structure. |
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2119 | clevermous | 28 | MAX_NUM_PARTITIONS = 256 |
29 | |||
30 | ; ============================================================================= |
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31 | ; ================================ Structures ================================= |
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32 | ; ============================================================================= |
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33 | ; This structure defines all callback functions for working with the physical |
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34 | ; device. They are implemented by a driver. Objects with this structure reside |
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35 | ; in a driver. |
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36 | struct DISKFUNC |
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2257 | killerkiri | 37 | .strucsize dd ? |
2119 | clevermous | 38 | ; Size of the structure. This field is intended for possible extensions of |
39 | ; this structure. If a new function is added to this structure and a driver |
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40 | ; implements an old version, the caller can detect this by checking .strucsize, |
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41 | ; so the driver remains compatible. |
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2257 | killerkiri | 42 | .close dd ? |
2119 | clevermous | 43 | ; The pointer to the function which frees all driver-specific resources for |
44 | ; the disk. |
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45 | ; Optional, may be NULL. |
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46 | ; void close(void* userdata); |
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2257 | killerkiri | 47 | .closemedia dd ? |
2119 | clevermous | 48 | ; The pointer to the function which informs the driver that the kernel has |
49 | ; finished all processing with the current media. If media is removed, the |
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50 | ; driver should decline all requests to that media with DISK_STATUS_NO_MEDIA, |
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51 | ; even if new media is inserted, until this function is called. If media is |
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52 | ; removed, a new call to 'disk_media_changed' is not allowed until this |
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53 | ; function is called. |
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54 | ; Optional, may be NULL (if media is not removable). |
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55 | ; void closemedia(void* userdata); |
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2257 | killerkiri | 56 | .querymedia dd ? |
2119 | clevermous | 57 | ; The pointer to the function which determines capabilities of the media. |
58 | ; int querymedia(void* userdata, DISKMEDIAINFO* info); |
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59 | ; Return value: one of DISK_STATUS_* |
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2257 | killerkiri | 60 | .read dd ? |
2119 | clevermous | 61 | ; The pointer to the function which reads data from the device. |
62 | ; int read(void* userdata, void* buffer, __int64 startsector, int* numsectors); |
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63 | ; input: *numsectors = number of sectors to read |
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64 | ; output: *numsectors = number of sectors which were successfully read |
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65 | ; Return value: one of DISK_STATUS_* |
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2257 | killerkiri | 66 | .write dd ? |
2119 | clevermous | 67 | ; The pointer to the function which writes data to the device. |
68 | ; Optional, may be NULL. |
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69 | ; int write(void* userdata, void* buffer, __int64 startsector, int* numsectors); |
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70 | ; input: *numsectors = number of sectors to write |
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71 | ; output: *numsectors = number of sectors which were successfully written |
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72 | ; Return value: one of DISK_STATUS_* |
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2257 | killerkiri | 73 | .flush dd ? |
2119 | clevermous | 74 | ; The pointer to the function which flushes the internal device cache. |
75 | ; Optional, may be NULL. |
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76 | ; int flush(void* userdata); |
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77 | ; Return value: one of DISK_STATUS_* |
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78 | ; Note that read/write are called by the cache manager, so a driver should not |
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79 | ; create a software cache. This function is implemented for flushing a hardware |
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80 | ; cache, if it exists. |
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2257 | killerkiri | 81 | .adjust_cache_size dd ? |
2140 | clevermous | 82 | ; The pointer to the function which returns the cache size for this device. |
83 | ; Optional, may be NULL. |
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84 | ; unsigned int adjust_cache_size(unsigned int suggested_size); |
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85 | ; Return value: 0 = disable cache, otherwise = used cache size in bytes. |
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2119 | clevermous | 86 | ends |
87 | |||
2257 | killerkiri | 88 | ; This structure holds information on a medium. |
89 | ; Objects with this structure are allocated by the kernel as a part of the DISK |
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90 | ; structure and are filled by a driver in the 'querymedia' callback. |
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2119 | clevermous | 91 | struct DISKMEDIAINFO |
2257 | killerkiri | 92 | .Flags dd ? |
2119 | clevermous | 93 | ; Combination of DISK_MEDIA_* bits. |
2257 | killerkiri | 94 | .SectorSize dd ? |
2119 | clevermous | 95 | ; Size of the sector. |
2257 | killerkiri | 96 | .Capacity dq ? |
2119 | clevermous | 97 | ; Size of the media in sectors. |
98 | ends |
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99 | |||
2257 | killerkiri | 100 | ; This structure represents the disk cache. To follow the old implementation, |
101 | ; there are two distinct caches for a disk, one for "system" data,and the other |
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2140 | clevermous | 102 | ; for "application" data. |
103 | struct DISKCACHE |
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2257 | killerkiri | 104 | .Lock MUTEX |
2140 | clevermous | 105 | ; Lock to protect the cache. |
106 | ; The following fields are inherited from data32.inc:cache_ideX. |
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107 | .pointer rd 1 |
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108 | .data_size rd 1 ; not use |
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2257 | killerkiri | 109 | .data rd 1 |
2140 | clevermous | 110 | .sad_size rd 1 |
2257 | killerkiri | 111 | .search_start rd 1 |
2140 | clevermous | 112 | ends |
113 | |||
2119 | clevermous | 114 | ; This structure represents a disk device and its media for the kernel. |
115 | ; This structure is allocated by the kernel in the 'disk_add' function, |
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116 | ; freed in the 'disk_dereference' function. |
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117 | struct DISK |
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118 | ; Fields of disk object |
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2257 | killerkiri | 119 | .Next dd ? |
120 | .Prev dd ? |
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2119 | clevermous | 121 | ; All disk devices are linked in one list with these two fields. |
122 | ; Head of the list is the 'disk_list' variable. |
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2257 | killerkiri | 123 | .Functions dd ? |
2119 | clevermous | 124 | ; Pointer to the 'DISKFUNC' structure with driver functions. |
2257 | killerkiri | 125 | .Name dd ? |
2119 | clevermous | 126 | ; Pointer to the string used for accesses through the global filesystem. |
2257 | killerkiri | 127 | .UserData dd ? |
2119 | clevermous | 128 | ; This field is passed to all callback functions so a driver can decide which |
129 | ; physical device is addressed. |
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2257 | killerkiri | 130 | .DriverFlags dd ? |
2119 | clevermous | 131 | ; Bitfield. Currently only DISK_NO_INSERT_NOTIFICATION bit is defined. |
132 | ; If it is set, the driver will never issue 'disk_media_changed' notification |
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133 | ; with argument set to true, so the kernel must try to detect media during |
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134 | ; requests from the file system. |
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2257 | killerkiri | 135 | .RefCount dd ? |
2119 | clevermous | 136 | ; Count of active references to this structure. One reference is kept during |
137 | ; the lifetime of the structure between 'disk_add' and 'disk_del'. |
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138 | ; Another reference is taken during any filesystem operation for this disk. |
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139 | ; One reference is added if media is inserted. |
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140 | ; The structure is destroyed when the reference count decrements to zero: |
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141 | ; this usually occurs in 'disk_del', but can be delayed to the end of last |
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142 | ; filesystem operation, if one is active. |
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2257 | killerkiri | 143 | .MediaLock MUTEX |
2119 | clevermous | 144 | ; Lock to protect the MEDIA structure. See the description after |
145 | ; 'disk_list_mutex' for the locking strategy. |
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146 | ; Fields of media object |
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2257 | killerkiri | 147 | .MediaInserted db ? |
2119 | clevermous | 148 | ; 0 if media is not inserted, nonzero otherwise. |
2257 | killerkiri | 149 | .MediaUsed db ? |
2119 | clevermous | 150 | ; 0 if media fields are not used, nonzero otherwise. If .MediaRefCount is |
151 | ; nonzero, this field is nonzero too; however, when .MediaRefCount goes |
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152 | ; to zero, there is some time interval during which media object is still used. |
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2257 | killerkiri | 153 | align 4 |
2119 | clevermous | 154 | ; The following fields are not valid unless either .MediaInserted is nonzero |
155 | ; or they are accessed from a code which has obtained the reference when |
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156 | ; .MediaInserted was nonzero. |
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2257 | killerkiri | 157 | .MediaRefCount dd ? |
2119 | clevermous | 158 | ; Count of active references to the media object. One reference is kept during |
159 | ; the lifetime of the media between two calls to 'disk_media_changed'. |
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160 | ; Another reference is taken during any filesystem operation for this media. |
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161 | ; The callback 'closemedia' is called when the reference count decrements to |
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162 | ; zero: this usually occurs in 'disk_media_changed', but can be delayed to the |
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2257 | killerkiri | 163 | ; end of the last filesystem operation, if one is active. |
164 | .MediaInfo DISKMEDIAINFO |
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165 | ; This field keeps information on the current media. |
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166 | .NumPartitions dd ? |
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2119 | clevermous | 167 | ; Number of partitions on this media. |
2257 | killerkiri | 168 | .Partitions dd ? |
2119 | clevermous | 169 | ; Pointer to array of .NumPartitions pointers to PARTITION structures. |
2257 | killerkiri | 170 | .cache_size dd ? |
2140 | clevermous | 171 | ; inherited from cache_ideX_size |
2257 | killerkiri | 172 | .SysCache DISKCACHE |
173 | .AppCache DISKCACHE |
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2140 | clevermous | 174 | ; Two caches for the disk. |
2119 | clevermous | 175 | ends |
176 | |||
177 | ; This structure represents one partition for the kernel. This is a base |
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178 | ; template, the actual contents after common fields is determined by the |
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2129 | serge | 179 | ; file system code for this partition. |
2119 | clevermous | 180 | struct PARTITION |
2257 | killerkiri | 181 | .FirstSector dq ? |
2119 | clevermous | 182 | ; First sector of the partition. |
2257 | killerkiri | 183 | .Length dq ? |
2119 | clevermous | 184 | ; Length of the partition in sectors. |
2257 | killerkiri | 185 | .Disk dd ? |
2140 | clevermous | 186 | ; Pointer to parent DISK structure. |
2257 | killerkiri | 187 | .FSUserFunctions dd ? |
2119 | clevermous | 188 | ; Handlers for the sysfunction 70h. This field is a pointer to the following |
189 | ; array. The first dword is a number of supported subfunctions, other dwords |
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190 | ; point to handlers of corresponding subfunctions. |
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191 | ; This field is 0 if file system is not recognized. |
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192 | ; ...fs-specific data may follow... |
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193 | ends |
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194 | |||
195 | ; This is an external structure, it represents an entry in the partition table. |
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196 | struct PARTITION_TABLE_ENTRY |
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2257 | killerkiri | 197 | .Bootable db ? |
2119 | clevermous | 198 | ; 80h = bootable partition, 0 = non-bootable partition, other values = invalid |
2257 | killerkiri | 199 | .FirstHead db ? |
200 | .FirstSector db ? |
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201 | .FirstTrack db ? |
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2119 | clevermous | 202 | ; Coordinates of first sector in CHS. |
2257 | killerkiri | 203 | .Type db ? |
2119 | clevermous | 204 | ; Partition type, one of predefined constants. 0 = empty, several types denote |
205 | ; extended partition (see process_partition_table_entry), we are not interested |
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206 | ; in other values. |
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2257 | killerkiri | 207 | .LastHead db ? |
208 | .LastSector db ? |
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209 | .LastTrack db ? |
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2119 | clevermous | 210 | ; Coordinates of last sector in CHS. |
2257 | killerkiri | 211 | .FirstAbsSector dd ? |
2119 | clevermous | 212 | ; Coordinate of first sector in LBA. |
2257 | killerkiri | 213 | .Length dd ? |
2119 | clevermous | 214 | ; Length of the partition in sectors. |
215 | ends |
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216 | |||
217 | ; ============================================================================= |
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218 | ; ================================ Global data ================================ |
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219 | ; ============================================================================= |
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220 | iglobal |
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221 | ; The pseudo-item for the list of all DISK structures. |
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222 | ; Initialized to the empty list. |
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223 | disk_list: |
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2257 | killerkiri | 224 | dd disk_list |
225 | dd disk_list |
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2119 | clevermous | 226 | endg |
227 | uglobal |
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228 | ; This mutex guards all operations with the global list of DISK structures. |
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2129 | serge | 229 | disk_list_mutex MUTEX |
2257 | killerkiri | 230 | ; * There are two dependent objects, a disk and a media. In the simplest case, |
2119 | clevermous | 231 | ; disk and media are both non-removable. However, in the general case both |
2257 | killerkiri | 232 | ; can be removed at any time, simultaneously or only media,and this makes things |
2119 | clevermous | 233 | ; complicated. |
234 | ; * For efficiency, both disk and media objects are located in the one |
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235 | ; structure named DISK. However, logically they are different. |
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236 | ; * The following operations use data of disk object: adding (disk_add); |
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237 | ; deleting (disk_del); filesystem (fs_lfn which eventually calls |
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238 | ; dyndisk_handler or dyndisk_enum_root). |
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239 | ; * The following operations use data of media object: adding/removing |
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240 | ; (disk_media_changed); filesystem (fs_lfn which eventually calls |
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241 | ; dyndisk_handler; dyndisk_enum_root doesn't work with media). |
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242 | ; * Notifications disk_add, disk_media_changed, disk_del are synchronized |
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243 | ; between themselves, this is a requirement for the driver. However, file |
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244 | ; system operations are asynchronous, can be issued at any time by any |
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245 | ; thread. |
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246 | ; * We must prevent a situation when a filesystem operation thinks that the |
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247 | ; object is still valid but in fact the notification has destroyed the |
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248 | ; object. So we keep a reference counter for both disk and media and destroy |
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249 | ; the object when this counter goes to zero. |
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250 | ; * The driver must know when it is safe to free driver-allocated resources. |
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251 | ; The object can be alive even after death notification has completed. |
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252 | ; We use special callbacks to satisfy both assertions: 'close' for the disk |
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253 | ; and 'closemedia' for the media. The destruction of the object includes |
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254 | ; calling the corresponding callback. |
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255 | ; * Each filesystem operation keeps one reference for the disk and one |
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256 | ; reference for the media. Notification disk_del forces notification on the |
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257 | ; media death, so the reference counter for the disk is always not less than |
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258 | ; the reference counter for the media. |
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259 | ; * Two operations "get the object" and "increment the reference counter" can |
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260 | ; not be done simultaneously. We use a mutex to guard the consistency here. |
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261 | ; It must be a part of the container for the object, so that this mutex can |
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262 | ; be acquired as a part of getting the object from the container. The |
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263 | ; container for disk object is the global list, and this list is guarded by |
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264 | ; 'disk_list_mutex'. The container for media object is the disk object, and |
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265 | ; the corresponding mutex is DISK.MediaLock. |
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266 | ; * Notifications do not change the data of objects, they can only remove |
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267 | ; objects. Thus we don't need another synchronization at this level. If two |
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268 | ; filesystem operations are referencing the same filesystem data, this is |
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269 | ; better resolved at the level of the filesystem. |
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270 | endg |
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271 | |||
272 | iglobal |
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2140 | clevermous | 273 | ; The function 'disk_scan_partitions' needs three 512-byte buffers for |
274 | ; MBR, bootsector and fs-temporary sector data. It can not use the static |
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275 | ; buffers always, since it can be called for two or more disks in parallel. |
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276 | ; However, this case is not typical. We reserve three static 512-byte buffers |
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277 | ; and a flag that these buffers are currently used. If 'disk_scan_partitions' |
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278 | ; detects that the buffers are currently used, it allocates buffers from the |
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279 | ; heap. |
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2119 | clevermous | 280 | ; The flag is implemented as a global dword variable. When the static buffers |
281 | ; are not used, the value is -1. When the static buffers are used, the value |
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282 | ; is normally 0 and temporarily can become greater. The function increments |
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283 | ; this value. If the resulting value is zero, it uses the buffers and |
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284 | ; decrements the value when the job is done. Otherwise, it immediately |
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285 | ; decrements the value and uses buffers from the heap, allocated in the |
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286 | ; beginning and freed in the end. |
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2257 | killerkiri | 287 | partition_buffer_users dd -1 |
2119 | clevermous | 288 | endg |
289 | uglobal |
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2140 | clevermous | 290 | ; The static buffers for MBR, bootsector and fs-temporary sector data. |
2119 | clevermous | 291 | align 16 |
2257 | killerkiri | 292 | mbr_buffer rb 512 |
293 | bootsect_buffer rb 512 |
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294 | fs_tmp_buffer rb 512 |
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2119 | clevermous | 295 | endg |
296 | |||
297 | iglobal |
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298 | ; This is the array of default implementations of driver callbacks. |
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299 | ; Same as DRIVERFUNC structure except for the first field; all functions must |
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300 | ; have the default implementations. |
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301 | align 4 |
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302 | disk_default_callbacks: |
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2257 | killerkiri | 303 | dd disk_default_close |
304 | dd disk_default_closemedia |
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305 | dd disk_default_querymedia |
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306 | dd disk_default_read |
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307 | dd disk_default_write |
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308 | dd disk_default_flush |
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309 | dd disk_default_adjust_cache_size |
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2119 | clevermous | 310 | endg |
311 | |||
312 | ; ============================================================================= |
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313 | ; ================================= Functions ================================= |
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314 | ; ============================================================================= |
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315 | |||
316 | ; This function registers a disk device. |
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317 | ; This includes: |
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318 | ; - allocating an internal structure describing this device; |
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319 | ; - registering this structure in the global filesystem. |
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320 | ; The function initializes the disk as if there is no media. If a media is |
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321 | ; present, the function 'disk_media_changed' should be called after this |
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322 | ; function succeeds. |
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323 | ; Parameters: |
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324 | ; [esp+4] = pointer to DISKFUNC structure with the callbacks |
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325 | ; [esp+8] = pointer to name (ASCIIZ string) |
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326 | ; [esp+12] = userdata to be passed to the callbacks as is. |
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327 | ; [esp+16] = flags, bitfield. Currently only DISK_NO_INSERT_NOTIFICATION bit |
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328 | ; is defined. |
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329 | ; Return value: |
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330 | ; NULL = operation has failed |
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331 | ; non-NULL = handle of the disk. This handle can be used |
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332 | ; in the operations with other Disk* functions. |
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333 | ; The handle is the pointer to the internal structure DISK. |
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334 | disk_add: |
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2257 | killerkiri | 335 | push ebx esi ; save used registers to be stdcall |
2119 | clevermous | 336 | ; 1. Allocate the DISK structure. |
337 | ; 1a. Call the heap manager. |
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2257 | killerkiri | 338 | push sizeof.DISK |
339 | pop eax |
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340 | call malloc |
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2119 | clevermous | 341 | ; 1b. Check the result. If allocation failed, return (go to 9) with eax = 0. |
2257 | killerkiri | 342 | test eax, eax |
343 | jz .nothing |
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344 | ; 2. Copy the disk name to the DISK structure. |
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2119 | clevermous | 345 | ; 2a. Get length of the name, including the terminating zero. |
2257 | killerkiri | 346 | mov ebx, [esp+8+8] ; ebx = pointer to name |
347 | push eax ; save allocated pointer to DISK |
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348 | xor eax, eax ; the argument of malloc() is in eax |
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2119 | clevermous | 349 | @@: |
2257 | killerkiri | 350 | inc eax |
351 | cmp byte [ebx+eax-1], 0 |
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352 | jnz @b |
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2119 | clevermous | 353 | ; 2b. Call the heap manager. |
2257 | killerkiri | 354 | call malloc |
2119 | clevermous | 355 | ; 2c. Check the result. If allocation failed, go to 7. |
2257 | killerkiri | 356 | pop esi ; restore allocated pointer to DISK |
357 | test eax, eax |
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358 | jz .free |
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2119 | clevermous | 359 | ; 2d. Store the allocated pointer to the DISK structure. |
2257 | killerkiri | 360 | mov [esi+DISK.Name], eax |
2119 | clevermous | 361 | ; 2e. Copy the name. |
362 | @@: |
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2257 | killerkiri | 363 | mov dl, [ebx] |
364 | mov [eax], dl |
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365 | inc ebx |
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366 | inc eax |
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367 | test dl, dl |
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368 | jnz @b |
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2119 | clevermous | 369 | ; 3. Copy other arguments of the function to the DISK structure. |
2257 | killerkiri | 370 | mov eax, [esp+4+8] |
371 | mov [esi+DISK.Functions], eax |
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372 | mov eax, [esp+12+8] |
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373 | mov [esi+DISK.UserData], eax |
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374 | mov eax, [esp+16+8] |
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375 | mov [esi+DISK.DriverFlags], eax |
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2119 | clevermous | 376 | ; 4. Initialize other fields of the DISK structure. |
2140 | clevermous | 377 | ; Media is not inserted, reference counter is 1. |
2257 | killerkiri | 378 | lea ecx, [esi+DISK.MediaLock] |
379 | call mutex_init |
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380 | xor eax, eax |
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381 | mov dword [esi+DISK.MediaInserted], eax |
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382 | inc eax |
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383 | mov [esi+DISK.RefCount], eax |
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2119 | clevermous | 384 | ; The DISK structure is initialized. |
385 | ; 5. Insert the new structure to the global list. |
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386 | ; 5a. Acquire the mutex. |
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2257 | killerkiri | 387 | mov ecx, disk_list_mutex |
388 | call mutex_lock |
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2119 | clevermous | 389 | ; 5b. Insert item to the tail of double-linked list. |
2257 | killerkiri | 390 | mov edx, disk_list |
391 | list_add_tail esi, edx ;esi= new edx= list head |
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2119 | clevermous | 392 | ; 5c. Release the mutex. |
2257 | killerkiri | 393 | call mutex_unlock |
2119 | clevermous | 394 | ; 6. Return with eax = pointer to DISK. |
2257 | killerkiri | 395 | xchg eax, esi |
396 | jmp .nothing |
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2119 | clevermous | 397 | .free: |
398 | ; Memory allocation for DISK structure succeeded, but for disk name failed. |
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399 | ; 7. Free the DISK structure. |
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2257 | killerkiri | 400 | xchg eax, esi |
401 | call free |
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2119 | clevermous | 402 | ; 8. Return with eax = 0. |
2257 | killerkiri | 403 | xor eax, eax |
2119 | clevermous | 404 | .nothing: |
405 | ; 9. Return. |
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2257 | killerkiri | 406 | pop esi ebx ; restore used registers to be stdcall |
407 | ret 16 ; purge 4 dword arguments to be stdcall |
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2119 | clevermous | 408 | |
409 | ; This function deletes a disk device from the global filesystem. |
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410 | ; This includes: |
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411 | ; - removing a media including all partitions; |
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412 | ; - deleting this structure from the global filesystem; |
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413 | ; - dereferencing the DISK structure and possibly destroying it. |
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414 | ; Parameters: |
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415 | ; [esp+4] = handle of the disk, i.e. the pointer to the DISK structure. |
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416 | ; Return value: none. |
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417 | disk_del: |
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2257 | killerkiri | 418 | push esi ; save used registers to be stdcall |
2119 | clevermous | 419 | ; 1. Force media to be removed. If the media is already removed, the |
420 | ; call does nothing. |
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2257 | killerkiri | 421 | mov esi, [esp+4+8] ; esi = handle of the disk |
422 | stdcall disk_media_changed, esi, 0 |
||
2119 | clevermous | 423 | ; 2. Delete the structure from the global list. |
424 | ; 2a. Acquire the mutex. |
||
2257 | killerkiri | 425 | mov ecx, disk_list_mutex |
426 | call mutex_lock |
||
2119 | clevermous | 427 | ; 2b. Delete item from double-linked list. |
2257 | killerkiri | 428 | mov eax, [esi+DISK.Next] |
429 | mov edx, [esi+DISK.Prev] |
||
430 | mov [eax+DISK.Prev], edx |
||
431 | mov [edx+DISK.Next], eax |
||
2119 | clevermous | 432 | ; 2c. Release the mutex. |
2257 | killerkiri | 433 | call mutex_unlock |
2119 | clevermous | 434 | ; 3. The structure still has one reference created in disk_add. Remove this |
435 | ; reference. If there are no other references, disk_dereference will free the |
||
436 | ; structure. |
||
2257 | killerkiri | 437 | call disk_dereference |
2119 | clevermous | 438 | ; 4. Return. |
2257 | killerkiri | 439 | pop esi ; restore used registers to be stdcall |
440 | ret 4 ; purge 1 dword argument to be stdcall |
||
2119 | clevermous | 441 | |
442 | ; This is an internal function which removes a previously obtained reference |
||
443 | ; to the disk. If this is the last reference, this function lets the driver |
||
444 | ; finalize all associated data, and afterwards frees the DISK structure. |
||
445 | ; esi = pointer to DISK structure |
||
446 | disk_dereference: |
||
447 | ; 1. Decrement reference counter. Use atomic operation to correctly handle |
||
448 | ; possible simultaneous calls. |
||
2257 | killerkiri | 449 | lock dec [esi+DISK.RefCount] |
2119 | clevermous | 450 | ; 2. If the result is nonzero, there are other references, so nothing to do. |
451 | ; In this case, return (go to 4). |
||
2257 | killerkiri | 452 | jnz .nothing |
2119 | clevermous | 453 | ; 3. If we are here, we just removed the last reference and must destroy the |
454 | ; disk object. |
||
455 | ; 3a. Call the driver. |
||
2257 | killerkiri | 456 | mov al, DISKFUNC.close |
457 | stdcall disk_call_driver |
||
2119 | clevermous | 458 | ; 3b. Free the structure. |
2257 | killerkiri | 459 | xchg eax, esi |
460 | call free |
||
2119 | clevermous | 461 | ; 4. Return. |
462 | .nothing: |
||
2257 | killerkiri | 463 | ret |
2119 | clevermous | 464 | |
465 | ; This is an internal function which removes a previously obtained reference |
||
466 | ; to the media. If this is the last reference, this function calls 'closemedia' |
||
467 | ; callback to signal the driver that the processing has finished and it is safe |
||
468 | ; to inform about a new media. |
||
469 | ; esi = pointer to DISK structure |
||
470 | disk_media_dereference: |
||
471 | ; 1. Decrement reference counter. Use atomic operation to correctly handle |
||
472 | ; possible simultaneous calls. |
||
2257 | killerkiri | 473 | lock dec [esi+DISK.MediaRefCount] |
2119 | clevermous | 474 | ; 2. If the result is nonzero, there are other references, so nothing to do. |
475 | ; In this case, return (go to 4). |
||
2257 | killerkiri | 476 | jnz .nothing |
2119 | clevermous | 477 | ; 3. If we are here, we just removed the last reference and must destroy the |
478 | ; media object. |
||
479 | ; Note that the same place inside the DISK structure is reused for all media |
||
480 | ; objects, so we must guarantee that reusing does not happen while freeing. |
||
481 | ; Reusing is only possible when someone processes a new media. There are two |
||
482 | ; mutually exclusive variants: |
||
483 | ; * driver issues media insert notifications (DISK_NO_INSERT_NOTIFICATION bit |
||
484 | ; in DISK.DriverFlags is not set). In this case, we require from the driver |
||
485 | ; that such notification (except for the first one) can occur only after a |
||
486 | ; call to 'closemedia' callback. |
||
487 | ; * driver does not issue media insert notifications. In this case, the kernel |
||
488 | ; itself must sometimes check whether media is inserted. We have the flag |
||
489 | ; DISK.MediaUsed, visible to the kernel. This flag signals to the other parts |
||
490 | ; of kernel that the way is free. |
||
491 | ; In the first case other parts of the kernel do not use DISK.MediaUsed, so it |
||
492 | ; does not matter when this flag is cleared. In the second case this flag must |
||
493 | ; be cleared after all other actions, including call to 'closemedia'. |
||
494 | ; 3a. Free all partitions. |
||
2257 | killerkiri | 495 | push esi edi |
496 | mov edi, [esi+DISK.NumPartitions] |
||
497 | mov esi, [esi+DISK.Partitions] |
||
498 | test edi, edi |
||
499 | jz .nofree |
||
2119 | clevermous | 500 | .freeloop: |
2257 | killerkiri | 501 | lodsd |
502 | call free |
||
503 | dec edi |
||
504 | jnz .freeloop |
||
2119 | clevermous | 505 | .nofree: |
2257 | killerkiri | 506 | pop edi esi |
2140 | clevermous | 507 | ; 3b. Free the cache. |
2257 | killerkiri | 508 | call disk_free_cache |
2140 | clevermous | 509 | ; 3c. Call the driver. |
2257 | killerkiri | 510 | mov al, DISKFUNC.closemedia |
511 | stdcall disk_call_driver |
||
2140 | clevermous | 512 | ; 3d. Clear the flag. |
2257 | killerkiri | 513 | mov [esi+DISK.MediaUsed], 0 |
2119 | clevermous | 514 | .nothing: |
2257 | killerkiri | 515 | ret |
2119 | clevermous | 516 | |
517 | ; This function is called by the driver and informs the kernel that the media |
||
518 | ; has changed. If the media is non-removable, it is called exactly once |
||
519 | ; immediately after 'disk_add' and once from 'disk_del'. |
||
520 | ; Parameters: |
||
521 | ; [esp+4] = handle of the disk, i.e. the pointer to the DISK structure. |
||
522 | ; [esp+8] = new status of the media: zero = no media, nonzero = media inserted. |
||
523 | disk_media_changed: |
||
2257 | killerkiri | 524 | push ebx esi edi ; save used registers to be stdcall |
2119 | clevermous | 525 | ; 1. Remove the existing media, if it is present. |
2257 | killerkiri | 526 | mov esi, [esp+4+12] ; esi = pointer to DISK |
2119 | clevermous | 527 | ; 1a. Check whether it is present. Since DISK.MediaInserted is changed only |
528 | ; in this function and calls to this function are synchronized, no lock is |
||
529 | ; required for checking. |
||
2257 | killerkiri | 530 | cmp [esi+DISK.MediaInserted], 0 |
531 | jz .noremove |
||
2119 | clevermous | 532 | ; We really need to remove the media. |
533 | ; 1b. Acquire mutex. |
||
2257 | killerkiri | 534 | lea ecx, [esi+DISK.MediaLock] |
535 | call mutex_lock |
||
2119 | clevermous | 536 | ; 1c. Clear the flag. |
2257 | killerkiri | 537 | mov [esi+DISK.MediaInserted], 0 |
2119 | clevermous | 538 | ; 1d. Release mutex. |
2257 | killerkiri | 539 | call mutex_unlock |
2119 | clevermous | 540 | ; 1e. Remove the "lifetime" reference and possibly destroy the structure. |
2257 | killerkiri | 541 | call disk_media_dereference |
2119 | clevermous | 542 | .noremove: |
543 | ; 2. Test whether there is new media. |
||
2257 | killerkiri | 544 | cmp dword [esp+8+12], 0 |
545 | jz .noinsert |
||
2119 | clevermous | 546 | ; Yep, there is. |
547 | ; 3. Process the new media. We assume that all media fields are available to |
||
548 | ; use, see comments in 'disk_media_dereference' (this covers using by previous |
||
549 | ; media referencers) and note that calls to this function are synchronized |
||
550 | ; (this covers using by new media referencers). |
||
551 | ; 3a. Call the 'querymedia' callback. |
||
552 | ; .Flags are set to zero for possible future extensions. |
||
2257 | killerkiri | 553 | lea edx, [esi+DISK.MediaInfo] |
554 | and [edx+DISKMEDIAINFO.Flags], 0 |
||
555 | mov al, DISKFUNC.querymedia |
||
556 | stdcall disk_call_driver, edx |
||
2119 | clevermous | 557 | ; 3b. Check the result of the callback. Abort if it failed. |
2257 | killerkiri | 558 | test eax, eax |
559 | jnz .noinsert |
||
2140 | clevermous | 560 | ; 3c. Allocate the cache unless disabled by the driver. Abort if failed. |
2257 | killerkiri | 561 | call disk_init_cache |
562 | test al, al |
||
563 | jz .noinsert |
||
2140 | clevermous | 564 | ; 3d. Acquire the lifetime reference for the media object. |
2257 | killerkiri | 565 | inc [esi+DISK.MediaRefCount] |
2140 | clevermous | 566 | ; 3e. Scan for partitions. Ignore result; the list of partitions is valid even |
2119 | clevermous | 567 | ; on errors. |
2257 | killerkiri | 568 | call disk_scan_partitions |
2140 | clevermous | 569 | ; 3f. Media is inserted and available for use. |
2257 | killerkiri | 570 | inc [esi+DISK.MediaInserted] |
2119 | clevermous | 571 | .noinsert: |
572 | ; 4. Return. |
||
2257 | killerkiri | 573 | pop edi esi ebx ; restore used registers to be stdcall |
574 | ret 8 ; purge 2 dword arguments to be stdcall |
||
2119 | clevermous | 575 | |
576 | ; This function is a thunk for all functions of a disk driver. |
||
577 | ; It checks whether the referenced function is implemented in the driver. |
||
578 | ; If so, this function jumps to the function in the driver. |
||
579 | ; Otherwise, it jumps to the default implementation. |
||
580 | ; al = offset of function in the DISKFUNC structure; |
||
581 | ; esi = pointer to the DISK structure; |
||
582 | ; stack is the same as for the corresponding function except that the |
||
583 | ; first parameter (void* userdata) is prepended automatically. |
||
584 | disk_call_driver: |
||
2257 | killerkiri | 585 | movzx eax, al ; eax = offset of function in the DISKFUNC structure |
2119 | clevermous | 586 | ; 1. Prepend the first argument to the stack. |
2257 | killerkiri | 587 | pop ecx ; ecx = return address |
588 | push [esi+DISK.UserData] ; add argument |
||
589 | push ecx ; save return address |
||
2119 | clevermous | 590 | ; 2. Check that the required function is inside the table. If not, go to 5. |
2257 | killerkiri | 591 | mov ecx, [esi+DISK.Functions] |
592 | cmp eax, [ecx+DISKFUNC.strucsize] |
||
593 | jae .default |
||
2119 | clevermous | 594 | ; 3. Check that the required function is implemented. If not, go to 5. |
2257 | killerkiri | 595 | mov ecx, [ecx+eax] |
596 | test ecx, ecx |
||
597 | jz .default |
||
2119 | clevermous | 598 | ; 4. Jump to the required function. |
2257 | killerkiri | 599 | jmp ecx |
2119 | clevermous | 600 | .default: |
601 | ; 5. Driver does not implement the required function; use default implementation. |
||
2257 | killerkiri | 602 | jmp dword [disk_default_callbacks+eax-4] |
2119 | clevermous | 603 | |
604 | ; The default implementation of DISKFUNC.querymedia. |
||
605 | disk_default_querymedia: |
||
2257 | killerkiri | 606 | push DISK_STATUS_INVALID_CALL |
607 | pop eax |
||
608 | ret 8 |
||
2119 | clevermous | 609 | |
610 | ; The default implementation of DISKFUNC.read and DISKFUNC.write. |
||
611 | disk_default_read: |
||
612 | disk_default_write: |
||
2257 | killerkiri | 613 | push DISK_STATUS_INVALID_CALL |
614 | pop eax |
||
615 | ret 20 |
||
2119 | clevermous | 616 | |
617 | ; The default implementation of DISKFUNC.close, DISKFUNC.closemedia and |
||
618 | ; DISKFUNC.flush. |
||
619 | disk_default_close: |
||
620 | disk_default_closemedia: |
||
621 | disk_default_flush: |
||
2257 | killerkiri | 622 | xor eax, eax |
623 | ret 4 |
||
2119 | clevermous | 624 | |
2140 | clevermous | 625 | ; The default implementation of DISKFUNC.adjust_cache_size. |
626 | disk_default_adjust_cache_size: |
||
2257 | killerkiri | 627 | mov eax, [esp+4] |
628 | ret 4 |
||
2140 | clevermous | 629 | |
2257 | killerkiri | 630 | ; This is an internal function called from 'disk_media_changed' when a new media |
2119 | clevermous | 631 | ; is detected. It creates the list of partitions for the media. |
632 | ; If media is not partitioned, then the list consists of one partition which |
||
633 | ; covers all the media. |
||
634 | ; esi = pointer to the DISK structure. |
||
635 | disk_scan_partitions: |
||
636 | ; 1. Initialize .NumPartitions and .Partitions fields as zeros: empty list. |
||
2257 | killerkiri | 637 | and [esi+DISK.NumPartitions], 0 |
638 | and [esi+DISK.Partitions], 0 |
||
2119 | clevermous | 639 | ; 2. Currently we can work only with 512-bytes sectors. Check this restriction. |
640 | ; The only exception is 2048-bytes CD/DVD, but they are not supported yet by |
||
641 | ; this code. |
||
2257 | killerkiri | 642 | cmp [esi+DISK.MediaInfo.SectorSize], 512 |
643 | jz .doscan |
||
644 | DEBUGF 1,'K : sector size is %d, only 512 is supported\n',[esi+DISK.MediaInfo.SectorSize] |
||
645 | ret |
||
2119 | clevermous | 646 | .doscan: |
647 | ; 3. Acquire the buffer for MBR and bootsector tests. See the comment before |
||
648 | ; the 'partition_buffer_users' variable. |
||
2257 | killerkiri | 649 | mov ebx, mbr_buffer ; assume the global buffer is free |
650 | lock inc [partition_buffer_users] |
||
651 | jz .buffer_acquired ; yes, it is free |
||
652 | lock dec [partition_buffer_users] ; no, we must allocate |
||
653 | stdcall kernel_alloc, 512*3 |
||
654 | test eax, eax |
||
655 | jz .nothing |
||
656 | xchg eax, ebx |
||
2119 | clevermous | 657 | .buffer_acquired: |
658 | ; MBR/EBRs are organized in the chain. We use a loop over MBR/EBRs, but no |
||
659 | ; more than MAX_NUM_PARTITION times. |
||
660 | ; 4. Prepare things for the loop. |
||
661 | ; ebp will hold the sector number for current MBR/EBR. |
||
662 | ; [esp] will hold the sector number for current extended partition, if there |
||
663 | ; is one. |
||
664 | ; [esp+4] will hold the counter that prevents long loops. |
||
2257 | killerkiri | 665 | push ebp ; save ebp |
666 | push MAX_NUM_PARTITIONS ; the counter of max MBRs to process |
||
667 | xor ebp, ebp ; start from sector zero |
||
668 | push ebp ; no extended partition yet |
||
2119 | clevermous | 669 | .new_mbr: |
670 | ; 5. Read the current sector. |
||
671 | ; Note that 'read' callback operates with 64-bit sector numbers, so we must |
||
672 | ; push additional zero as a high dword of sector number. |
||
2257 | killerkiri | 673 | mov al, DISKFUNC.read |
674 | push 1 |
||
675 | stdcall disk_call_driver, ebx, ebp, 0, esp |
||
676 | pop ecx |
||
2119 | clevermous | 677 | ; 6. If the read has failed, abort the loop. |
2257 | killerkiri | 678 | dec ecx |
679 | jnz .mbr_failed |
||
2119 | clevermous | 680 | ; 7. Check the MBR/EBR signature. If it is wrong, abort the loop. |
681 | ; Soon we will access the partition table which starts at ebx+0x1BE, |
||
682 | ; so we can fill its address right now. If we do it now, then the addressing |
||
683 | ; [ecx+0x40] is shorter than [ebx+0x1fe]: one-byte offset vs 4-bytes offset. |
||
2257 | killerkiri | 684 | lea ecx, [ebx+0x1be] ; ecx -> partition table |
685 | cmp word [ecx+0x40], 0xaa55 |
||
686 | jnz .mbr_failed |
||
2119 | clevermous | 687 | ; 8. The MBR is treated differently from EBRs. For MBR we additionally need to |
688 | ; execute step 9 and possibly step 10. |
||
2257 | killerkiri | 689 | test ebp, ebp |
690 | jnz .mbr |
||
691 | ; The partition table can be present or not present. In the first case, we just |
||
692 | ; read the MBR. In the second case, we just read the bootsector for a |
||
2119 | clevermous | 693 | ; filesystem. |
2257 | killerkiri | 694 | ; The following algorithm is used to distinguish between these cases. |
2119 | clevermous | 695 | ; A. If at least one entry of the partition table is invalid, this is |
696 | ; a bootsector. See the description of 'is_partition_table_entry' for |
||
697 | ; definition of validity. |
||
698 | ; B. If all entries are empty (filesystem type field is zero) and the first |
||
699 | ; byte is jmp opcode (0EBh or 0E9h), this is a bootsector which happens to |
||
700 | ; have zeros in the place of partition table. |
||
2257 | killerkiri | 701 | ; C. Otherwise, this is an MBR. |
2119 | clevermous | 702 | ; 9. Test for MBR vs bootsector. |
703 | ; 9a. Check entries. If any is invalid, go to 10 (rule A). |
||
2257 | killerkiri | 704 | call is_partition_table_entry |
705 | jc .notmbr |
||
706 | add ecx, 10h |
||
707 | call is_partition_table_entry |
||
708 | jc .notmbr |
||
709 | add ecx, 10h |
||
710 | call is_partition_table_entry |
||
711 | jc .notmbr |
||
712 | add ecx, 10h |
||
713 | call is_partition_table_entry |
||
714 | jc .notmbr |
||
2119 | clevermous | 715 | ; 9b. Check types of the entries. If at least one is nonzero, go to 11 (rule C). |
2257 | killerkiri | 716 | mov al, [ecx-30h+PARTITION_TABLE_ENTRY.Type] |
717 | or al, [ecx-20h+PARTITION_TABLE_ENTRY.Type] |
||
718 | or al, [ecx-10h+PARTITION_TABLE_ENTRY.Type] |
||
719 | or al, [ecx+PARTITION_TABLE_ENTRY.Type] |
||
720 | jnz .mbr |
||
2119 | clevermous | 721 | ; 9c. Empty partition table or bootsector with many zeroes? (rule B) |
2257 | killerkiri | 722 | cmp byte [ebx], 0EBh |
723 | jz .notmbr |
||
724 | cmp byte [ebx], 0E9h |
||
725 | jnz .mbr |
||
2119 | clevermous | 726 | .notmbr: |
2257 | killerkiri | 727 | ; 10. This is not an MBR. The media is not partitioned. Create one partition |
2119 | clevermous | 728 | ; which covers all the media and abort the loop. |
2257 | killerkiri | 729 | stdcall disk_add_partition, 0, 0, \ |
730 | dword [esi+DISK.MediaInfo.Capacity], dword [esi+DISK.MediaInfo.Capacity+4] |
||
731 | jmp .done |
||
2119 | clevermous | 732 | .mbr: |
733 | ; 11. Process all entries of the new MBR/EBR |
||
2257 | killerkiri | 734 | lea ecx, [ebx+0x1be] ; ecx -> partition table |
735 | push 0 ; assume no extended partition |
||
736 | call process_partition_table_entry |
||
737 | add ecx, 10h |
||
738 | call process_partition_table_entry |
||
739 | add ecx, 10h |
||
740 | call process_partition_table_entry |
||
741 | add ecx, 10h |
||
742 | call process_partition_table_entry |
||
743 | pop ebp |
||
2119 | clevermous | 744 | ; 12. Test whether we found a new EBR and should continue the loop. |
745 | ; 12a. If there was no next EBR, return. |
||
2257 | killerkiri | 746 | test ebp, ebp |
747 | jz .done |
||
2119 | clevermous | 748 | ; Ok, we have EBR. |
749 | ; 12b. EBRs addresses are relative to the start of extended partition. |
||
750 | ; For simplicity, just abort if an 32-bit overflow occurs; large disks |
||
751 | ; are most likely partitioned with GPT, not MBR scheme, since the precise |
||
752 | ; calculation here would increase limit just twice at the price of big |
||
753 | ; compatibility problems. |
||
2257 | killerkiri | 754 | pop eax ; load extended partition |
755 | add ebp, eax |
||
756 | jc .mbr_failed |
||
2119 | clevermous | 757 | ; 12c. If extended partition has not yet started, start it. |
2257 | killerkiri | 758 | test eax, eax |
759 | jnz @f |
||
760 | mov eax, ebp |
||
2119 | clevermous | 761 | @@: |
762 | ; 12c. If the limit is not exceeded, continue the loop. |
||
2257 | killerkiri | 763 | dec dword [esp] |
764 | push eax ; store extended partition |
||
765 | jnz .new_mbr |
||
2119 | clevermous | 766 | .mbr_failed: |
767 | .done: |
||
768 | ; 13. Cleanup after the loop. |
||
2257 | killerkiri | 769 | pop eax ; not important anymore |
770 | pop eax ; not important anymore |
||
771 | pop ebp ; restore ebp |
||
2119 | clevermous | 772 | ; 14. Release the buffer. |
773 | ; 14a. Test whether it is the global buffer or we have allocated it. |
||
2257 | killerkiri | 774 | cmp ebx, mbr_buffer |
775 | jz .release_partition_buffer |
||
2119 | clevermous | 776 | ; 14b. If we have allocated it, free it. |
2257 | killerkiri | 777 | xchg eax, ebx |
778 | call free |
||
779 | jmp .nothing |
||
2119 | clevermous | 780 | ; 14c. Otherwise, release reference. |
781 | .release_partition_buffer: |
||
2257 | killerkiri | 782 | lock dec [partition_buffer_users] |
2119 | clevermous | 783 | .nothing: |
784 | ; 15. Return. |
||
2257 | killerkiri | 785 | ret |
2119 | clevermous | 786 | |
787 | ; This is an internal function called from disk_scan_partitions. It checks |
||
788 | ; whether the entry pointed to by ecx is a valid entry of partition table. |
||
789 | ; The entry is valid if the first byte is 0 or 80h, the first sector plus the |
||
790 | ; length is less than twice the size of media. Multiplication by two is |
||
791 | ; required since the size mentioned in the partition table can be slightly |
||
792 | ; greater than the real size. |
||
793 | is_partition_table_entry: |
||
794 | ; 1. Check .Bootable field. |
||
2257 | killerkiri | 795 | mov al, [ecx+PARTITION_TABLE_ENTRY.Bootable] |
796 | and al, 7Fh |
||
797 | jnz .invalid |
||
2119 | clevermous | 798 | ; 3. Calculate first sector + length. Note that .FirstAbsSector is relative |
799 | ; to the MBR/EBR, so the real sum is ebp + .FirstAbsSector + .Length. |
||
2257 | killerkiri | 800 | mov eax, ebp |
801 | xor edx, edx |
||
802 | add eax, [ecx+PARTITION_TABLE_ENTRY.FirstAbsSector] |
||
803 | adc edx, 0 |
||
804 | add eax, [ecx+PARTITION_TABLE_ENTRY.Length] |
||
805 | adc edx, 0 |
||
2119 | clevermous | 806 | ; 4. Divide by two. |
2257 | killerkiri | 807 | shr edx, 1 |
808 | rcr eax, 1 |
||
2119 | clevermous | 809 | ; 5. Compare with capacity. If the subtraction (edx:eax) - .Capacity does not |
810 | ; overflow, this is bad. |
||
2257 | killerkiri | 811 | sub eax, dword [esi+DISK.MediaInfo.Capacity] |
812 | sbb edx, dword [esi+DISK.MediaInfo.Capacity+4] |
||
813 | jnc .invalid |
||
2119 | clevermous | 814 | .valid: |
815 | ; 5. Return success: CF is cleared. |
||
2257 | killerkiri | 816 | clc |
817 | ret |
||
2119 | clevermous | 818 | .invalid: |
819 | ; 6. Return fail: CF is set. |
||
2257 | killerkiri | 820 | stc |
821 | ret |
||
2119 | clevermous | 822 | |
823 | ; This is an internal function called from disk_scan_partitions. It processes |
||
824 | ; the entry pointed to by ecx. |
||
825 | ; * If the entry is invalid, just ignore this entry. |
||
826 | ; * If the type is zero, just ignore this entry. |
||
827 | ; * If the type is one of types for extended partition, store the address |
||
828 | ; of this partition as the new MBR in [esp+4]. |
||
829 | ; * Otherwise, add the partition to the list of partitions for this disk. |
||
830 | ; We don't use the type from the entry to identify the file system; |
||
831 | ; fs-specific checks do this more reliably. |
||
832 | process_partition_table_entry: |
||
833 | ; 1. Check for valid entry. If invalid, return (go to 5). |
||
2257 | killerkiri | 834 | call is_partition_table_entry |
835 | jc .nothing |
||
2119 | clevermous | 836 | ; 2. Check for empty entry. If invalid, return (go to 5). |
2257 | killerkiri | 837 | mov al, [ecx+PARTITION_TABLE_ENTRY.Type] |
838 | test al, al |
||
839 | jz .nothing |
||
2119 | clevermous | 840 | ; 3. Check for extended partition. If extended, go to 6. |
841 | irp type,\ |
||
2257 | killerkiri | 842 | 0x05,\ ; DOS: extended partition |
843 | 0x0f,\ ; WIN95: extended partition, LBA-mapped |
||
844 | 0xc5,\ ; DRDOS/secured: extended partition |
||
845 | 0xd5 ; Old Multiuser DOS secured: extended partition |
||
2119 | clevermous | 846 | { |
2257 | killerkiri | 847 | cmp al, type |
848 | jz .extended |
||
2119 | clevermous | 849 | } |
850 | ; 4. If we are here, that is a normal partition. Add it to the list. |
||
851 | ; Note that the first sector is relative to MBR/EBR. |
||
2257 | killerkiri | 852 | mov eax, ebp |
853 | xor edx, edx |
||
854 | add eax, [ecx+PARTITION_TABLE_ENTRY.FirstAbsSector] |
||
855 | adc edx, 0 |
||
856 | push ecx |
||
857 | stdcall disk_add_partition, eax, edx, \ |
||
858 | [ecx+PARTITION_TABLE_ENTRY.Length], 0 |
||
859 | pop ecx |
||
2119 | clevermous | 860 | .nothing: |
861 | ; 5. Return. |
||
2257 | killerkiri | 862 | ret |
2119 | clevermous | 863 | .extended: |
864 | ; 6. If we are here, that is an extended partition. Store the address. |
||
2257 | killerkiri | 865 | mov eax, [ecx+PARTITION_TABLE_ENTRY.FirstAbsSector] |
866 | mov [esp+4], eax |
||
867 | ret |
||
2119 | clevermous | 868 | |
869 | ; This is an internal function called from disk_scan_partitions and |
||
870 | ; process_partition_table_entry. It adds one partition to the list of |
||
871 | ; partitions for the media. |
||
872 | proc disk_add_partition stdcall uses ebx edi, start:qword, length:qword |
||
873 | ; 1. Check that this partition will not exceed the limit on total number. |
||
2257 | killerkiri | 874 | cmp [esi+DISK.NumPartitions], MAX_NUM_PARTITIONS |
875 | jae .nothing |
||
2119 | clevermous | 876 | ; 2. Check that this partition does not overlap with any already registered |
877 | ; partition. Since any file system assumes that the disk data will not change |
||
878 | ; outside of its control, such overlap could be destructive. |
||
879 | ; Since the number of partitions is usually very small and is guaranteed not |
||
880 | ; to be large, the simple linear search is sufficient. |
||
881 | ; 2a. Prepare the loop: edi will point to the current item of .Partitions |
||
882 | ; array, ecx will be the current item, ebx will hold number of items left. |
||
2257 | killerkiri | 883 | mov edi, [esi+DISK.Partitions] |
884 | mov ebx, [esi+DISK.NumPartitions] |
||
885 | test ebx, ebx |
||
886 | jz .partitionok |
||
2119 | clevermous | 887 | .scan_existing: |
888 | ; 2b. Get the next partition. |
||
2257 | killerkiri | 889 | mov ecx, [edi] |
890 | add edi, 4 |
||
2119 | clevermous | 891 | ; The range [.FirstSector, .FirstSector+.Length) must be either entirely to |
892 | ; the left of [start, start+length) or entirely to the right. |
||
893 | ; 2c. Subtract .FirstSector - start. The possible overflow distinguish between |
||
2140 | clevermous | 894 | ; cases "to the left" (2e) and "to the right" (2d). |
2257 | killerkiri | 895 | mov eax, dword [ecx+PARTITION.FirstSector] |
896 | mov edx, dword [ecx+PARTITION.FirstSector+4] |
||
897 | sub eax, dword [start] |
||
898 | sbb edx, dword [start+4] |
||
899 | jb .less |
||
2119 | clevermous | 900 | ; 2d. .FirstSector is greater than or equal to start. Check that .FirstSector |
901 | ; is greater than or equal to start+length; the subtraction |
||
902 | ; (.FirstSector-start) - length must not cause overflow. Go to 2g if life is |
||
903 | ; good or to 2f in the other case. |
||
2257 | killerkiri | 904 | sub eax, dword [length] |
905 | sbb edx, dword [length+4] |
||
906 | jb .overlap |
||
907 | jmp .next_existing |
||
2119 | clevermous | 908 | .less: |
909 | ; 2e. .FirstSector is less than start. Check that .FirstSector+.Length is less |
||
910 | ; than or equal to start. If the addition (.FirstSector-start) + .Length does |
||
911 | ; not cause overflow, then .FirstSector + .Length is strictly less than start; |
||
912 | ; since the equality is also valid, use decrement preliminarily. Go to 2g or |
||
913 | ; 2f depending on the overflow. |
||
2257 | killerkiri | 914 | sub eax, 1 |
915 | sbb edx, 0 |
||
916 | add eax, dword [ecx+PARTITION.Length] |
||
917 | adc edx, dword [ecx+PARTITION.Length+4] |
||
918 | jnc .next_existing |
||
2119 | clevermous | 919 | .overlap: |
920 | ; 2f. The partition overlaps with previously registered partition. Say warning |
||
921 | ; and return with nothing done. |
||
2257 | killerkiri | 922 | dbgstr 'two partitions overlap, ignoring the last one' |
923 | jmp .nothing |
||
2119 | clevermous | 924 | .next_existing: |
925 | ; 2g. The partition does not overlap with the current partition. Continue the |
||
926 | ; loop. |
||
2257 | killerkiri | 927 | dec ebx |
928 | jnz .scan_existing |
||
2119 | clevermous | 929 | .partitionok: |
930 | ; 3. The partition has passed tests. Reallocate the partitions array for a new |
||
931 | ; entry. |
||
932 | ; 3a. Call the allocator. |
||
2257 | killerkiri | 933 | mov eax, [esi+DISK.NumPartitions] |
934 | inc eax ; one more entry |
||
935 | shl eax, 2 ; each entry is dword |
||
936 | call malloc |
||
2119 | clevermous | 937 | ; 3b. Test the result. If failed, return with nothing done. |
2257 | killerkiri | 938 | test eax, eax |
939 | jz .nothing |
||
2119 | clevermous | 940 | ; 3c. Copy the old array to the new array. |
2257 | killerkiri | 941 | mov edi, eax |
942 | push esi |
||
943 | mov ecx, [esi+DISK.NumPartitions] |
||
944 | mov esi, [esi+DISK.Partitions] |
||
945 | rep movsd |
||
946 | pop esi |
||
2119 | clevermous | 947 | ; 3d. Set the field in the DISK structure to the new array. |
2257 | killerkiri | 948 | xchg [esi+DISK.Partitions], eax |
2119 | clevermous | 949 | ; 3e. Free the old array. |
2257 | killerkiri | 950 | call free |
2119 | clevermous | 951 | ; 4. Recognize the file system. |
952 | ; 4a. Call the filesystem recognizer. It will allocate the PARTITION structure |
||
953 | ; with possible filesystem-specific fields. |
||
2257 | killerkiri | 954 | call disk_detect_partition |
2119 | clevermous | 955 | ; 4b. Check return value. If zero, return with list not changed; so far only |
956 | ; the array was reallocated, this is ok for other code. |
||
2257 | killerkiri | 957 | test eax, eax |
958 | jz .nothing |
||
2119 | clevermous | 959 | ; 5. Insert the new partition to the list. |
2257 | killerkiri | 960 | stosd |
961 | inc [esi+DISK.NumPartitions] |
||
2119 | clevermous | 962 | ; 6. Return. |
963 | .nothing: |
||
2257 | killerkiri | 964 | ret |
2119 | clevermous | 965 | endp |
966 | |||
967 | ; This is an internal function called from disk_add_partition. |
||
968 | ; It tries to recognize the file system on the partition and allocates the |
||
969 | ; corresponding PARTITION structure with filesystem-specific fields. |
||
970 | disk_detect_partition: |
||
971 | ; This function inherits the stack frame from disk_add_partition. In stdcall |
||
972 | ; with ebp-based frame arguments start from ebp+8, since [ebp]=saved ebp |
||
973 | ; and [ebp+4]=return address. |
||
974 | virtual at ebp+8 |
||
2257 | killerkiri | 975 | .start dq ? |
976 | .length dq ? |
||
2119 | clevermous | 977 | end virtual |
978 | ; Currently no file systems are supported, so just allocate the PARTITION |
||
979 | ; structure without extra fields. |
||
980 | ; 1. Allocate and check result. |
||
2257 | killerkiri | 981 | push sizeof.PARTITION |
982 | pop eax |
||
983 | call malloc |
||
984 | test eax, eax |
||
985 | jz .nothing |
||
2119 | clevermous | 986 | ; 2. Fill the common fields: copy .start and .length. |
2257 | killerkiri | 987 | mov edx, dword [.start] |
988 | mov dword [eax+PARTITION.FirstSector], edx |
||
989 | mov edx, dword [.start+4] |
||
990 | mov dword [eax+PARTITION.FirstSector+4], edx |
||
991 | mov edx, dword [.length] |
||
992 | mov dword [eax+PARTITION.Length], edx |
||
993 | mov edx, dword [.length+4] |
||
994 | mov dword [eax+PARTITION.Length+4], edx |
||
2119 | clevermous | 995 | .nothing: |
996 | ; 3. Return with eax = pointer to PARTITION or NULL. |
||
2257 | killerkiri | 997 | ret |
2119 | clevermous | 998 | |
999 | ; This function is called from file_system_lfn. |
||
1000 | ; This handler gets the control each time when fn 70 is called |
||
1001 | ; with unknown item of root subdirectory. |
||
1002 | ; in: esi -> name |
||
1003 | ; ebp = 0 or rest of name relative to esi |
||
1004 | ; out: if the handler processes path, it must not return in file_system_lfn, |
||
1005 | ; but instead pop return address and return directly to the caller |
||
1006 | ; otherwise simply return |
||
1007 | dyndisk_handler: |
||
2257 | killerkiri | 1008 | push ebx edi ; save registers used in file_system_lfn |
2119 | clevermous | 1009 | ; 1. Acquire the mutex. |
2257 | killerkiri | 1010 | mov ecx, disk_list_mutex |
1011 | call mutex_lock |
||
2119 | clevermous | 1012 | ; 2. Loop over the list of DISK structures. |
1013 | ; 2a. Initialize. |
||
2257 | killerkiri | 1014 | mov ebx, disk_list |
2119 | clevermous | 1015 | .scan: |
1016 | ; 2b. Get the next item. |
||
2257 | killerkiri | 1017 | mov ebx, [ebx+DISK.Next] |
2119 | clevermous | 1018 | ; 2c. Check whether the list is done. If so, go to 3. |
2257 | killerkiri | 1019 | cmp ebx, disk_list |
1020 | jz .notfound |
||
2119 | clevermous | 1021 | ; 2d. Compare names. If names match, go to 5. |
2257 | killerkiri | 1022 | mov edi, [ebx+DISK.Name] |
1023 | push esi |
||
2119 | clevermous | 1024 | @@: |
1025 | ; esi points to the name from fs operation; it is terminated by zero or slash. |
||
2257 | killerkiri | 1026 | lodsb |
1027 | test al, al |
||
1028 | jz .eoin_dec |
||
1029 | cmp al, '/' |
||
1030 | jz .eoin |
||
2119 | clevermous | 1031 | ; edi points to the disk name. |
2257 | killerkiri | 1032 | inc edi |
2119 | clevermous | 1033 | ; edi points to lowercase name, this is a requirement for the driver. |
1034 | ; Characters at esi can have any register. Lowercase the current character. |
||
1035 | ; This lowercasing works for latin letters and digits; since the disk name |
||
1036 | ; should not contain other symbols, this is ok. |
||
2257 | killerkiri | 1037 | or al, 20h |
1038 | cmp al, [edi-1] |
||
1039 | jz @b |
||
2119 | clevermous | 1040 | .wrongname: |
1041 | ; 2f. Names don't match. Continue the loop. |
||
2257 | killerkiri | 1042 | pop esi |
1043 | jmp .scan |
||
2119 | clevermous | 1044 | .notfound: |
1045 | ; The loop is done and no name matches. |
||
1046 | ; 3. Release the mutex. |
||
2257 | killerkiri | 1047 | call mutex_unlock |
2119 | clevermous | 1048 | ; 4. Return normally. |
2257 | killerkiri | 1049 | pop edi ebx ; restore registers used in file_system_lfn |
1050 | ret |
||
2119 | clevermous | 1051 | ; part of 2d: the name matches partially, but we must check that this is full |
1052 | ; equality. |
||
1053 | .eoin_dec: |
||
2257 | killerkiri | 1054 | dec esi |
2119 | clevermous | 1055 | .eoin: |
2257 | killerkiri | 1056 | cmp byte [edi], 0 |
1057 | jnz .wrongname |
||
2119 | clevermous | 1058 | ; We found the addressed DISK structure. |
1059 | ; 5. Reference the disk. |
||
2257 | killerkiri | 1060 | lock inc [ebx+DISK.RefCount] |
2119 | clevermous | 1061 | ; 6. Now we are sure that the DISK structure is not going to die at least |
1062 | ; while we are working with it, so release the global mutex. |
||
2257 | killerkiri | 1063 | call mutex_unlock |
2119 | clevermous | 1064 | ; 7. Acquire the mutex for media object. |
2257 | killerkiri | 1065 | pop edi ; restore edi |
1066 | lea ecx, [ebx+DISK.MediaLock] |
||
1067 | call mutex_lock |
||
2119 | clevermous | 1068 | ; 8. Get the media object. If it is not NULL, reference it. |
2257 | killerkiri | 1069 | xor edx, edx |
1070 | cmp [ebx+DISK.MediaInserted], dl |
||
1071 | jz @f |
||
1072 | mov edx, ebx |
||
1073 | inc [ebx+DISK.MediaRefCount] |
||
2119 | clevermous | 1074 | @@: |
1075 | ; 9. Now we are sure that the media object, if it exists, is not going to die |
||
1076 | ; at least while we are working with it, so release the mutex for media object. |
||
2257 | killerkiri | 1077 | call mutex_unlock |
1078 | mov ecx, ebx |
||
1079 | pop ebx eax ; restore ebx, pop return address |
||
2119 | clevermous | 1080 | ; 10. Check whether the fs operation wants to enumerate partitions (go to 11) |
1081 | ; or work with some concrete partition (go to 12). |
||
2257 | killerkiri | 1082 | cmp byte [esi], 0 |
1083 | jnz .haspartition |
||
2119 | clevermous | 1084 | ; 11. The fs operation wants to enumerate partitions. |
1085 | ; 11a. Only "list directory" operation is applicable to / |
||
1086 | ; the operation code. If wrong, go to 13. |
||
2257 | killerkiri | 1087 | cmp dword [ebx], 1 |
1088 | jnz .access_denied |
||
2119 | clevermous | 1089 | ; 11b. If the media is inserted, use 'fs_dyndisk_next' as an enumeration |
1090 | ; procedure. Otherwise, use 'fs_dyndisk_next_nomedia'. |
||
2257 | killerkiri | 1091 | mov esi, fs_dyndisk_next_nomedia |
1092 | test edx, edx |
||
1093 | jz @f |
||
1094 | mov esi, fs_dyndisk_next |
||
2119 | clevermous | 1095 | @@: |
1096 | ; 11c. Let the procedure from fs_lfn.inc do the job. |
||
2257 | killerkiri | 1097 | jmp file_system_lfn.maindir_noesi |
2119 | clevermous | 1098 | .haspartition: |
1099 | ; 12. The fs operation has specified some partition. |
||
1100 | ; 12a. Store parameters for callback functions. |
||
2257 | killerkiri | 1101 | push edx |
1102 | push ecx |
||
2119 | clevermous | 1103 | ; 12b. Store callback functions. |
2257 | killerkiri | 1104 | push dyndisk_cleanup |
1105 | push fs_dyndisk |
||
1106 | mov edi, esp |
||
2119 | clevermous | 1107 | ; 12c. Let the procedure from fs_lfn.inc do the job. |
2257 | killerkiri | 1108 | jmp file_system_lfn.found2 |
2119 | clevermous | 1109 | .access_denied: |
1110 | ; 13. Fail the operation with the appropriate code. |
||
2257 | killerkiri | 1111 | mov dword [esp+32], ERROR_ACCESS_DENIED |
2119 | clevermous | 1112 | .cleanup: |
1113 | ; 14. Cleanup. |
||
2257 | killerkiri | 1114 | mov esi, ecx ; disk*dereference assume that esi points to DISK |
2119 | clevermous | 1115 | .cleanup_esi: |
2257 | killerkiri | 1116 | test edx, edx ; if there are no media, we didn't reference it |
1117 | jz @f |
||
1118 | call disk_media_dereference |
||
2119 | clevermous | 1119 | @@: |
2257 | killerkiri | 1120 | call disk_dereference |
2119 | clevermous | 1121 | ; 15. Return. |
2257 | killerkiri | 1122 | ret |
2119 | clevermous | 1123 | |
1124 | ; This is a callback for cleaning up things called from file_system_lfn.found2. |
||
1125 | dyndisk_cleanup: |
||
2257 | killerkiri | 1126 | mov esi, [edi+8] |
1127 | mov edx, [edi+12] |
||
1128 | jmp dyndisk_handler.cleanup_esi |
||
2119 | clevermous | 1129 | |
1130 | ; This is a callback for enumerating partitions called from |
||
1131 | ; file_system_lfn.maindir in the case of inserted media. |
||
1132 | ; It just increments eax until DISK.NumPartitions reached and then |
||
1133 | ; cleans up. |
||
1134 | fs_dyndisk_next: |
||
2257 | killerkiri | 1135 | cmp eax, [ecx+DISK.NumPartitions] |
1136 | jae .nomore |
||
1137 | inc eax |
||
1138 | clc |
||
1139 | ret |
||
2119 | clevermous | 1140 | .nomore: |
2257 | killerkiri | 1141 | pusha |
1142 | mov esi, ecx |
||
1143 | call disk_media_dereference |
||
1144 | call disk_dereference |
||
1145 | popa |
||
1146 | stc |
||
1147 | ret |
||
2119 | clevermous | 1148 | |
1149 | ; This is a callback for enumerating partitions called from |
||
1150 | ; file_system_lfn.maindir in the case of missing media. |
||
1151 | ; In this case we create one pseudo-partition. |
||
1152 | fs_dyndisk_next_nomedia: |
||
2257 | killerkiri | 1153 | cmp eax, 1 |
1154 | jae .nomore |
||
1155 | inc eax |
||
1156 | clc |
||
1157 | ret |
||
2119 | clevermous | 1158 | .nomore: |
2257 | killerkiri | 1159 | pusha |
1160 | mov esi, ecx |
||
1161 | call disk_dereference |
||
1162 | popa |
||
1163 | stc |
||
1164 | ret |
||
2119 | clevermous | 1165 | |
1166 | ; This is a callback for doing real work with selected partition. |
||
1167 | ; Currently this is just placeholder, since no file systems are supported. |
||
1168 | ; edi = esp -> {dd fs_dyndisk, dd dyndisk_cleanup, dd pointer to DISK, dd media object} |
||
1169 | ; ecx = partition number, esi+ebp = ASCIIZ name |
||
1170 | fs_dyndisk: |
||
2257 | killerkiri | 1171 | dec ecx ; convert to zero-based partition index |
1172 | pop edx edx edx eax ; edx = pointer to DISK, eax = NULL or edx |
||
1173 | test eax, eax |
||
1174 | jz .nomedia |
||
2119 | clevermous | 1175 | .main: |
2257 | killerkiri | 1176 | cmp ecx, [edx+DISK.NumPartitions] |
1177 | jae .notfound |
||
1178 | mov dword [esp+32], ERROR_UNKNOWN_FS |
||
2119 | clevermous | 1179 | .cleanup: |
2257 | killerkiri | 1180 | mov esi, edx |
1181 | call disk_media_dereference |
||
1182 | call disk_dereference |
||
1183 | ret |
||
2119 | clevermous | 1184 | .notfound: |
2257 | killerkiri | 1185 | mov dword [esp+32], ERROR_FILE_NOT_FOUND |
1186 | jmp .cleanup |
||
2119 | clevermous | 1187 | .nomedia: |
2257 | killerkiri | 1188 | test ecx, ecx |
1189 | jnz .notfound |
||
1190 | test byte [edx+DISK.DriverFlags], DISK_NO_INSERT_NOTIFICATION |
||
1191 | jz .deverror |
||
2119 | clevermous | 1192 | ; if the driver does not support insert notifications and we are the only fs |
1193 | ; operation with this disk, issue the fake insert notification; if media is |
||
1194 | ; still not inserted, 'disk_media_changed' will detect this and do nothing |
||
2129 | serge | 1195 | ;;; push ebx |
2257 | killerkiri | 1196 | lea ecx, [edx+DISK.MediaLock] |
1197 | call mutex_lock |
||
1198 | cmp [edx+DISK.MediaRefCount], 1 |
||
1199 | jnz .noluck |
||
1200 | call mutex_unlock |
||
1201 | push edx |
||
1202 | stdcall disk_media_changed, edx, 1 |
||
1203 | pop edx |
||
1204 | lea ecx, [edx+DISK.MediaLock] |
||
1205 | call mutex_lock |
||
1206 | cmp [edx+DISK.MediaInserted], 0 |
||
1207 | jz .noluck |
||
1208 | lock inc [edx+DISK.MediaRefCount] |
||
1209 | call mutex_unlock |
||
1210 | xor ecx, ecx |
||
1211 | jmp .main |
||
2119 | clevermous | 1212 | .noluck: |
2257 | killerkiri | 1213 | call mutex_unlock |
2119 | clevermous | 1214 | .deverror: |
2257 | killerkiri | 1215 | mov dword [esp+32], ERROR_DEVICE |
1216 | mov esi, edx |
||
1217 | call disk_dereference |
||
1218 | ret |
||
2119 | clevermous | 1219 | |
1220 | ; This function is called from file_system_lfn. |
||
1221 | ; This handler is called when virtual root is enumerated |
||
1222 | ; and must return all items which can be handled by this. |
||
1223 | ; It is called several times, first time with eax=0 |
||
1224 | ; in: eax = 0 for first call, previously returned value for subsequent calls |
||
1225 | ; out: eax = 0 => no more items |
||
1226 | ; eax != 0 => buffer pointed to by edi contains name of item |
||
1227 | dyndisk_enum_root: |
||
2257 | killerkiri | 1228 | push edx ; save register used in file_system_lfn |
1229 | mov ecx, disk_list_mutex ; it will be useful |
||
2119 | clevermous | 1230 | ; 1. If this is the first call, acquire the mutex and initialize. |
2257 | killerkiri | 1231 | test eax, eax |
1232 | jnz .notfirst |
||
1233 | call mutex_lock |
||
1234 | mov eax, disk_list |
||
2119 | clevermous | 1235 | .notfirst: |
1236 | ; 2. Get next item. |
||
2257 | killerkiri | 1237 | mov eax, [eax+DISK.Next] |
2119 | clevermous | 1238 | ; 3. If there are no more items, go to 6. |
2257 | killerkiri | 1239 | cmp eax, disk_list |
1240 | jz .last |
||
2119 | clevermous | 1241 | ; 4. Copy name from the DISK structure to edi. |
2257 | killerkiri | 1242 | push eax esi |
1243 | mov esi, [eax+DISK.Name] |
||
2119 | clevermous | 1244 | @@: |
2257 | killerkiri | 1245 | lodsb |
1246 | stosb |
||
1247 | test al, al |
||
1248 | jnz @b |
||
1249 | pop esi eax |
||
2119 | clevermous | 1250 | ; 5. Return with eax = item. |
2257 | killerkiri | 1251 | pop edx ; restore register used in file_system_lfn |
1252 | ret |
||
2119 | clevermous | 1253 | .last: |
1254 | ; 6. Release the mutex and return with eax = 0. |
||
2257 | killerkiri | 1255 | call mutex_unlock |
1256 | xor eax, eax |
||
1257 | pop edx ; restore register used in file_system_lfn |
||
1258 | ret |