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2288 | clevermous | 1 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
2 | ;; ;; |
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5363 | yogev_ezra | 3 | ;; Copyright (C) KolibriOS team 2011-2015. All rights reserved. ;; |
2288 | clevermous | 4 | ;; Distributed under terms of the GNU General Public License ;; |
5 | ;; ;; |
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6 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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7 | |||
8 | $Revision: 6468 $ |
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9 | |||
10 | ; ============================================================================= |
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11 | ; ================================= Constants ================================= |
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12 | ; ============================================================================= |
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13 | ; Error codes for callback functions. |
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14 | DISK_STATUS_OK = 0 ; success |
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15 | DISK_STATUS_GENERAL_ERROR = -1; if no other code is suitable |
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16 | DISK_STATUS_INVALID_CALL = 1 ; invalid input parameters |
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17 | DISK_STATUS_NO_MEDIA = 2 ; no media present |
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18 | DISK_STATUS_END_OF_MEDIA = 3 ; end of media while reading/writing data |
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4437 | clevermous | 19 | DISK_STATUS_NO_MEMORY = 4 ; insufficient memory for driver operation |
2288 | clevermous | 20 | ; Driver flags. Represent bits in DISK.DriverFlags. |
21 | DISK_NO_INSERT_NOTIFICATION = 1 |
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22 | ; Media flags. Represent bits in DISKMEDIAINFO.Flags. |
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23 | DISK_MEDIA_READONLY = 1 |
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24 | |||
25 | ; If too many partitions are detected,there is probably an error on the disk. |
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26 | ; 256 partitions should be enough for any reasonable use. |
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27 | ; Also, the same number is limiting the number of MBRs to process; if |
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28 | ; too many MBRs are visible,there probably is a loop in the MBR structure. |
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29 | MAX_NUM_PARTITIONS = 256 |
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30 | |||
31 | ; ============================================================================= |
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32 | ; ================================ Structures ================================= |
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33 | ; ============================================================================= |
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34 | ; This structure defines all callback functions for working with the physical |
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35 | ; device. They are implemented by a driver. Objects with this structure reside |
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36 | ; in a driver. |
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2381 | hidnplayr | 37 | struct DISKFUNC |
38 | strucsize dd ? |
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2288 | clevermous | 39 | ; Size of the structure. This field is intended for possible extensions of |
40 | ; this structure. If a new function is added to this structure and a driver |
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41 | ; implements an old version, the caller can detect this by checking .strucsize, |
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42 | ; so the driver remains compatible. |
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2381 | hidnplayr | 43 | close dd ? |
2288 | clevermous | 44 | ; The pointer to the function which frees all driver-specific resources for |
45 | ; the disk. |
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46 | ; Optional, may be NULL. |
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47 | ; void close(void* userdata); |
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2381 | hidnplayr | 48 | closemedia dd ? |
2288 | clevermous | 49 | ; The pointer to the function which informs the driver that the kernel has |
50 | ; finished all processing with the current media. If media is removed, the |
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51 | ; driver should decline all requests to that media with DISK_STATUS_NO_MEDIA, |
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52 | ; even if new media is inserted, until this function is called. If media is |
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53 | ; removed, a new call to 'disk_media_changed' is not allowed until this |
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54 | ; function is called. |
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55 | ; Optional, may be NULL (if media is not removable). |
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56 | ; void closemedia(void* userdata); |
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2381 | hidnplayr | 57 | querymedia dd ? |
2288 | clevermous | 58 | ; The pointer to the function which determines capabilities of the media. |
59 | ; int querymedia(void* userdata, DISKMEDIAINFO* info); |
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60 | ; Return value: one of DISK_STATUS_* |
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2381 | hidnplayr | 61 | read dd ? |
2288 | clevermous | 62 | ; The pointer to the function which reads data from the device. |
63 | ; int read(void* userdata, void* buffer, __int64 startsector, int* numsectors); |
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64 | ; input: *numsectors = number of sectors to read |
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65 | ; output: *numsectors = number of sectors which were successfully read |
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66 | ; Return value: one of DISK_STATUS_* |
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2381 | hidnplayr | 67 | write dd ? |
2288 | clevermous | 68 | ; The pointer to the function which writes data to the device. |
69 | ; Optional, may be NULL. |
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70 | ; int write(void* userdata, void* buffer, __int64 startsector, int* numsectors); |
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71 | ; input: *numsectors = number of sectors to write |
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72 | ; output: *numsectors = number of sectors which were successfully written |
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73 | ; Return value: one of DISK_STATUS_* |
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2381 | hidnplayr | 74 | flush dd ? |
2288 | clevermous | 75 | ; The pointer to the function which flushes the internal device cache. |
76 | ; Optional, may be NULL. |
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77 | ; int flush(void* userdata); |
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78 | ; Return value: one of DISK_STATUS_* |
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79 | ; Note that read/write are called by the cache manager, so a driver should not |
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80 | ; create a software cache. This function is implemented for flushing a hardware |
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81 | ; cache, if it exists. |
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2381 | hidnplayr | 82 | adjust_cache_size dd ? |
2288 | clevermous | 83 | ; The pointer to the function which returns the cache size for this device. |
84 | ; Optional, may be NULL. |
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85 | ; unsigned int adjust_cache_size(unsigned int suggested_size); |
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86 | ; Return value: 0 = disable cache, otherwise = used cache size in bytes. |
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87 | ends |
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88 | |||
89 | ; This structure holds information on a medium. |
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90 | ; Objects with this structure are allocated by the kernel as a part of the DISK |
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91 | ; structure and are filled by a driver in the 'querymedia' callback. |
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2381 | hidnplayr | 92 | struct DISKMEDIAINFO |
93 | Flags dd ? |
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2288 | clevermous | 94 | ; Combination of DISK_MEDIA_* bits. |
2381 | hidnplayr | 95 | SectorSize dd ? |
2288 | clevermous | 96 | ; Size of the sector. |
2381 | hidnplayr | 97 | Capacity dq ? |
2288 | clevermous | 98 | ; Size of the media in sectors. |
99 | ends |
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100 | |||
101 | ; This structure represents the disk cache. To follow the old implementation, |
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102 | ; there are two distinct caches for a disk, one for "system" data,and the other |
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103 | ; for "application" data. |
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2381 | hidnplayr | 104 | struct DISKCACHE |
2288 | clevermous | 105 | ; The following fields are inherited from data32.inc:cache_ideX. |
2381 | hidnplayr | 106 | pointer dd ? |
107 | data_size dd ? ; unused |
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108 | data dd ? |
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109 | sad_size dd ? |
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110 | search_start dd ? |
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5089 | clevermous | 111 | sector_size_log dd ? |
2288 | clevermous | 112 | ends |
113 | |||
114 | ; This structure represents a disk device and its media for the kernel. |
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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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2381 | hidnplayr | 117 | struct DISK |
2288 | clevermous | 118 | ; Fields of disk object |
2381 | hidnplayr | 119 | Next dd ? |
120 | Prev dd ? |
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2288 | 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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2381 | hidnplayr | 123 | Functions dd ? |
2288 | clevermous | 124 | ; Pointer to the 'DISKFUNC' structure with driver functions. |
2381 | hidnplayr | 125 | Name dd ? |
2288 | clevermous | 126 | ; Pointer to the string used for accesses through the global filesystem. |
2381 | hidnplayr | 127 | UserData dd ? |
2288 | 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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2381 | hidnplayr | 130 | DriverFlags dd ? |
2288 | 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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2381 | hidnplayr | 135 | RefCount dd ? |
2288 | 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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2381 | hidnplayr | 143 | MediaLock MUTEX |
2288 | 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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2381 | hidnplayr | 147 | MediaInserted db ? |
2288 | clevermous | 148 | ; 0 if media is not inserted, nonzero otherwise. |
2381 | hidnplayr | 149 | MediaUsed db ? |
2288 | 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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3460 | clevermous | 153 | dw ? ; padding |
2288 | 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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2381 | hidnplayr | 157 | MediaRefCount dd ? |
2288 | 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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163 | ; end of the last filesystem operation, if one is active. |
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2381 | hidnplayr | 164 | MediaInfo DISKMEDIAINFO |
2288 | clevermous | 165 | ; This field keeps information on the current media. |
2381 | hidnplayr | 166 | NumPartitions dd ? |
2288 | clevermous | 167 | ; Number of partitions on this media. |
2381 | hidnplayr | 168 | Partitions dd ? |
2288 | clevermous | 169 | ; Pointer to array of .NumPartitions pointers to PARTITION structures. |
2381 | hidnplayr | 170 | cache_size dd ? |
2288 | clevermous | 171 | ; inherited from cache_ideX_size |
4437 | clevermous | 172 | CacheLock MUTEX |
173 | ; Lock to protect both caches. |
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2381 | hidnplayr | 174 | SysCache DISKCACHE |
175 | AppCache DISKCACHE |
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2288 | clevermous | 176 | ; Two caches for the disk. |
177 | ends |
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178 | |||
179 | ; This structure represents one partition for the kernel. This is a base |
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180 | ; template, the actual contents after common fields is determined by the |
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181 | ; file system code for this partition. |
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2381 | hidnplayr | 182 | struct PARTITION |
183 | FirstSector dq ? |
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2288 | clevermous | 184 | ; First sector of the partition. |
2381 | hidnplayr | 185 | Length dq ? |
2288 | clevermous | 186 | ; Length of the partition in sectors. |
2381 | hidnplayr | 187 | Disk dd ? |
2288 | clevermous | 188 | ; Pointer to parent DISK structure. |
2381 | hidnplayr | 189 | FSUserFunctions dd ? |
2288 | clevermous | 190 | ; Handlers for the sysfunction 70h. This field is a pointer to the following |
3742 | clevermous | 191 | ; array. The first dword is pointer to disconnect handler. |
192 | ; The first dword is a number of supported subfunctions, other dwords |
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2288 | clevermous | 193 | ; point to handlers of corresponding subfunctions. |
194 | ; ...fs-specific data may follow... |
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195 | ends |
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196 | |||
197 | ; This is an external structure, it represents an entry in the partition table. |
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2381 | hidnplayr | 198 | struct PARTITION_TABLE_ENTRY |
199 | Bootable db ? |
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2288 | clevermous | 200 | ; 80h = bootable partition, 0 = non-bootable partition, other values = invalid |
2381 | hidnplayr | 201 | FirstHead db ? |
202 | FirstSector db ? |
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203 | FirstTrack db ? |
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2288 | clevermous | 204 | ; Coordinates of first sector in CHS. |
2381 | hidnplayr | 205 | Type db ? |
2288 | clevermous | 206 | ; Partition type, one of predefined constants. 0 = empty, several types denote |
207 | ; extended partition (see process_partition_table_entry), we are not interested |
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208 | ; in other values. |
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2381 | hidnplayr | 209 | LastHead db ? |
210 | LastSector db ? |
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211 | LastTrack db ? |
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2288 | clevermous | 212 | ; Coordinates of last sector in CHS. |
2381 | hidnplayr | 213 | FirstAbsSector dd ? |
2288 | clevermous | 214 | ; Coordinate of first sector in LBA. |
2381 | hidnplayr | 215 | Length dd ? |
2288 | clevermous | 216 | ; Length of the partition in sectors. |
217 | ends |
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218 | |||
219 | ; ============================================================================= |
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220 | ; ================================ Global data ================================ |
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221 | ; ============================================================================= |
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222 | iglobal |
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223 | ; The pseudo-item for the list of all DISK structures. |
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224 | ; Initialized to the empty list. |
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225 | disk_list: |
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226 | dd disk_list |
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227 | dd disk_list |
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228 | endg |
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229 | uglobal |
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230 | ; This mutex guards all operations with the global list of DISK structures. |
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231 | disk_list_mutex MUTEX |
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232 | ; * There are two dependent objects, a disk and a media. In the simplest case, |
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233 | ; disk and media are both non-removable. However, in the general case both |
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234 | ; can be removed at any time, simultaneously or only media,and this makes things |
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235 | ; complicated. |
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236 | ; * For efficiency, both disk and media objects are located in the one |
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237 | ; structure named DISK. However, logically they are different. |
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238 | ; * The following operations use data of disk object: adding (disk_add); |
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239 | ; deleting (disk_del); filesystem (fs_lfn which eventually calls |
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240 | ; dyndisk_handler or dyndisk_enum_root). |
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241 | ; * The following operations use data of media object: adding/removing |
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242 | ; (disk_media_changed); filesystem (fs_lfn which eventually calls |
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243 | ; dyndisk_handler; dyndisk_enum_root doesn't work with media). |
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244 | ; * Notifications disk_add, disk_media_changed, disk_del are synchronized |
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245 | ; between themselves, this is a requirement for the driver. However, file |
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246 | ; system operations are asynchronous, can be issued at any time by any |
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247 | ; thread. |
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248 | ; * We must prevent a situation when a filesystem operation thinks that the |
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249 | ; object is still valid but in fact the notification has destroyed the |
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250 | ; object. So we keep a reference counter for both disk and media and destroy |
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251 | ; the object when this counter goes to zero. |
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252 | ; * The driver must know when it is safe to free driver-allocated resources. |
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253 | ; The object can be alive even after death notification has completed. |
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254 | ; We use special callbacks to satisfy both assertions: 'close' for the disk |
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255 | ; and 'closemedia' for the media. The destruction of the object includes |
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256 | ; calling the corresponding callback. |
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257 | ; * Each filesystem operation keeps one reference for the disk and one |
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258 | ; reference for the media. Notification disk_del forces notification on the |
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259 | ; media death, so the reference counter for the disk is always not less than |
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260 | ; the reference counter for the media. |
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261 | ; * Two operations "get the object" and "increment the reference counter" can |
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262 | ; not be done simultaneously. We use a mutex to guard the consistency here. |
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263 | ; It must be a part of the container for the object, so that this mutex can |
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264 | ; be acquired as a part of getting the object from the container. The |
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265 | ; container for disk object is the global list, and this list is guarded by |
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266 | ; 'disk_list_mutex'. The container for media object is the disk object, and |
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267 | ; the corresponding mutex is DISK.MediaLock. |
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268 | ; * Notifications do not change the data of objects, they can only remove |
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269 | ; objects. Thus we don't need another synchronization at this level. If two |
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270 | ; filesystem operations are referencing the same filesystem data, this is |
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271 | ; better resolved at the level of the filesystem. |
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272 | endg |
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273 | |||
274 | iglobal |
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5089 | clevermous | 275 | ; The function 'disk_scan_partitions' needs three sector-sized buffers for |
2288 | clevermous | 276 | ; MBR, bootsector and fs-temporary sector data. It can not use the static |
277 | ; buffers always, since it can be called for two or more disks in parallel. |
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278 | ; However, this case is not typical. We reserve three static 512-byte buffers |
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279 | ; and a flag that these buffers are currently used. If 'disk_scan_partitions' |
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280 | ; detects that the buffers are currently used, it allocates buffers from the |
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5089 | clevermous | 281 | ; heap. Also, the heap is used when sector size is other than 512. |
2288 | clevermous | 282 | ; The flag is implemented as a global dword variable. When the static buffers |
283 | ; are not used, the value is -1. When the static buffers are used, the value |
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284 | ; is normally 0 and temporarily can become greater. The function increments |
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285 | ; this value. If the resulting value is zero, it uses the buffers and |
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286 | ; decrements the value when the job is done. Otherwise, it immediately |
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287 | ; decrements the value and uses buffers from the heap, allocated in the |
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288 | ; beginning and freed in the end. |
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289 | partition_buffer_users dd -1 |
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290 | endg |
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291 | uglobal |
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292 | ; The static buffers for MBR, bootsector and fs-temporary sector data. |
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293 | align 16 |
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294 | mbr_buffer rb 512 |
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295 | bootsect_buffer rb 512 |
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296 | fs_tmp_buffer rb 512 |
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297 | endg |
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298 | |||
299 | iglobal |
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300 | ; This is the array of default implementations of driver callbacks. |
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301 | ; Same as DRIVERFUNC structure except for the first field; all functions must |
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302 | ; have the default implementations. |
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303 | align 4 |
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304 | disk_default_callbacks: |
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305 | dd disk_default_close |
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306 | dd disk_default_closemedia |
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307 | dd disk_default_querymedia |
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308 | dd disk_default_read |
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309 | dd disk_default_write |
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310 | dd disk_default_flush |
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311 | dd disk_default_adjust_cache_size |
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312 | endg |
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313 | |||
314 | ; ============================================================================= |
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315 | ; ================================= Functions ================================= |
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316 | ; ============================================================================= |
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317 | |||
318 | ; This function registers a disk device. |
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319 | ; This includes: |
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320 | ; - allocating an internal structure describing this device; |
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321 | ; - registering this structure in the global filesystem. |
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322 | ; The function initializes the disk as if there is no media. If a media is |
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323 | ; present, the function 'disk_media_changed' should be called after this |
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324 | ; function succeeds. |
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325 | ; Parameters: |
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326 | ; [esp+4] = pointer to DISKFUNC structure with the callbacks |
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327 | ; [esp+8] = pointer to name (ASCIIZ string) |
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328 | ; [esp+12] = userdata to be passed to the callbacks as is. |
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329 | ; [esp+16] = flags, bitfield. Currently only DISK_NO_INSERT_NOTIFICATION bit |
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330 | ; is defined. |
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331 | ; Return value: |
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332 | ; NULL = operation has failed |
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333 | ; non-NULL = handle of the disk. This handle can be used |
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334 | ; in the operations with other Disk* functions. |
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335 | ; The handle is the pointer to the internal structure DISK. |
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336 | disk_add: |
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337 | push ebx esi ; save used registers to be stdcall |
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338 | ; 1. Allocate the DISK structure. |
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339 | ; 1a. Call the heap manager. |
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3598 | clevermous | 340 | movi eax, sizeof.DISK |
2288 | clevermous | 341 | call malloc |
342 | ; 1b. Check the result. If allocation failed, return (go to 9) with eax = 0. |
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343 | test eax, eax |
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344 | jz .nothing |
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345 | ; 2. Copy the disk name to the DISK structure. |
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346 | ; 2a. Get length of the name, including the terminating zero. |
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347 | mov ebx, [esp+8+8] ; ebx = pointer to name |
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348 | push eax ; save allocated pointer to DISK |
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349 | xor eax, eax ; the argument of malloc() is in eax |
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350 | @@: |
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351 | inc eax |
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352 | cmp byte [ebx+eax-1], 0 |
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353 | jnz @b |
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3681 | clevermous | 354 | ; 2b. Call the heap manager. |
2288 | clevermous | 355 | call malloc |
356 | ; 2c. Check the result. If allocation failed, go to 7. |
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357 | pop esi ; restore allocated pointer to DISK |
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358 | test eax, eax |
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359 | jz .free |
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360 | ; 2d. Store the allocated pointer to the DISK structure. |
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361 | mov [esi+DISK.Name], eax |
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362 | ; 2e. Copy the name. |
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363 | @@: |
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364 | mov dl, [ebx] |
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365 | mov [eax], dl |
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366 | inc ebx |
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367 | inc eax |
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368 | test dl, dl |
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369 | jnz @b |
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370 | ; 3. Copy other arguments of the function to the DISK structure. |
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371 | mov eax, [esp+4+8] |
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372 | mov [esi+DISK.Functions], eax |
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373 | mov eax, [esp+12+8] |
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374 | mov [esi+DISK.UserData], eax |
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375 | mov eax, [esp+16+8] |
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376 | mov [esi+DISK.DriverFlags], eax |
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377 | ; 4. Initialize other fields of the DISK structure. |
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378 | ; Media is not inserted, reference counter is 1. |
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379 | lea ecx, [esi+DISK.MediaLock] |
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380 | call mutex_init |
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381 | xor eax, eax |
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382 | mov dword [esi+DISK.MediaInserted], eax |
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3460 | clevermous | 383 | mov [esi+DISK.MediaRefCount], eax |
2288 | clevermous | 384 | inc eax |
385 | mov [esi+DISK.RefCount], eax |
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386 | ; The DISK structure is initialized. |
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387 | ; 5. Insert the new structure to the global list. |
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388 | ; 5a. Acquire the mutex. |
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389 | mov ecx, disk_list_mutex |
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390 | call mutex_lock |
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391 | ; 5b. Insert item to the tail of double-linked list. |
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392 | mov edx, disk_list |
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393 | list_add_tail esi, edx ;esi= new edx= list head |
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394 | ; 5c. Release the mutex. |
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395 | call mutex_unlock |
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396 | ; 6. Return with eax = pointer to DISK. |
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397 | xchg eax, esi |
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398 | jmp .nothing |
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399 | .free: |
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400 | ; Memory allocation for DISK structure succeeded, but for disk name failed. |
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401 | ; 7. Free the DISK structure. |
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402 | xchg eax, esi |
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403 | call free |
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404 | ; 8. Return with eax = 0. |
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405 | xor eax, eax |
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406 | .nothing: |
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407 | ; 9. Return. |
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408 | pop esi ebx ; restore used registers to be stdcall |
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409 | ret 16 ; purge 4 dword arguments to be stdcall |
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410 | |||
411 | ; This function deletes a disk device from the global filesystem. |
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412 | ; This includes: |
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413 | ; - removing a media including all partitions; |
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414 | ; - deleting this structure from the global filesystem; |
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415 | ; - dereferencing the DISK structure and possibly destroying it. |
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416 | ; Parameters: |
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417 | ; [esp+4] = handle of the disk, i.e. the pointer to the DISK structure. |
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418 | ; Return value: none. |
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419 | disk_del: |
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420 | push esi ; save used registers to be stdcall |
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421 | ; 1. Force media to be removed. If the media is already removed, the |
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422 | ; call does nothing. |
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2643 | clevermous | 423 | mov esi, [esp+4+4] ; esi = handle of the disk |
2288 | clevermous | 424 | stdcall disk_media_changed, esi, 0 |
425 | ; 2. Delete the structure from the global list. |
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426 | ; 2a. Acquire the mutex. |
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427 | mov ecx, disk_list_mutex |
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428 | call mutex_lock |
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429 | ; 2b. Delete item from double-linked list. |
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430 | mov eax, [esi+DISK.Next] |
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431 | mov edx, [esi+DISK.Prev] |
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432 | mov [eax+DISK.Prev], edx |
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433 | mov [edx+DISK.Next], eax |
||
434 | ; 2c. Release the mutex. |
||
435 | call mutex_unlock |
||
436 | ; 3. The structure still has one reference created in disk_add. Remove this |
||
437 | ; reference. If there are no other references, disk_dereference will free the |
||
438 | ; structure. |
||
439 | call disk_dereference |
||
440 | ; 4. Return. |
||
441 | pop esi ; restore used registers to be stdcall |
||
442 | ret 4 ; purge 1 dword argument to be stdcall |
||
443 | |||
444 | ; This is an internal function which removes a previously obtained reference |
||
445 | ; to the disk. If this is the last reference, this function lets the driver |
||
446 | ; finalize all associated data, and afterwards frees the DISK structure. |
||
447 | ; esi = pointer to DISK structure |
||
448 | disk_dereference: |
||
449 | ; 1. Decrement reference counter. Use atomic operation to correctly handle |
||
450 | ; possible simultaneous calls. |
||
451 | lock dec [esi+DISK.RefCount] |
||
452 | ; 2. If the result is nonzero, there are other references, so nothing to do. |
||
453 | ; In this case, return (go to 4). |
||
454 | jnz .nothing |
||
455 | ; 3. If we are here, we just removed the last reference and must destroy the |
||
456 | ; disk object. |
||
457 | ; 3a. Call the driver. |
||
458 | mov al, DISKFUNC.close |
||
459 | stdcall disk_call_driver |
||
460 | ; 3b. Free the structure. |
||
461 | xchg eax, esi |
||
3202 | clevermous | 462 | push ebx |
2288 | clevermous | 463 | call free |
3202 | clevermous | 464 | pop ebx |
2288 | clevermous | 465 | ; 4. Return. |
466 | .nothing: |
||
467 | ret |
||
468 | |||
469 | ; This is an internal function which removes a previously obtained reference |
||
470 | ; to the media. If this is the last reference, this function calls 'closemedia' |
||
471 | ; callback to signal the driver that the processing has finished and it is safe |
||
472 | ; to inform about a new media. |
||
473 | ; esi = pointer to DISK structure |
||
474 | disk_media_dereference: |
||
475 | ; 1. Decrement reference counter. Use atomic operation to correctly handle |
||
476 | ; possible simultaneous calls. |
||
477 | lock dec [esi+DISK.MediaRefCount] |
||
478 | ; 2. If the result is nonzero, there are other references, so nothing to do. |
||
479 | ; In this case, return (go to 4). |
||
480 | jnz .nothing |
||
481 | ; 3. If we are here, we just removed the last reference and must destroy the |
||
482 | ; media object. |
||
483 | ; Note that the same place inside the DISK structure is reused for all media |
||
484 | ; objects, so we must guarantee that reusing does not happen while freeing. |
||
485 | ; Reusing is only possible when someone processes a new media. There are two |
||
486 | ; mutually exclusive variants: |
||
487 | ; * driver issues media insert notifications (DISK_NO_INSERT_NOTIFICATION bit |
||
488 | ; in DISK.DriverFlags is not set). In this case, we require from the driver |
||
489 | ; that such notification (except for the first one) can occur only after a |
||
490 | ; call to 'closemedia' callback. |
||
491 | ; * driver does not issue media insert notifications. In this case, the kernel |
||
492 | ; itself must sometimes check whether media is inserted. We have the flag |
||
493 | ; DISK.MediaUsed, visible to the kernel. This flag signals to the other parts |
||
494 | ; of kernel that the way is free. |
||
495 | ; In the first case other parts of the kernel do not use DISK.MediaUsed, so it |
||
496 | ; does not matter when this flag is cleared. In the second case this flag must |
||
497 | ; be cleared after all other actions, including call to 'closemedia'. |
||
498 | ; 3a. Free all partitions. |
||
499 | push esi edi |
||
500 | mov edi, [esi+DISK.NumPartitions] |
||
501 | mov esi, [esi+DISK.Partitions] |
||
502 | test edi, edi |
||
503 | jz .nofree |
||
504 | .freeloop: |
||
505 | lodsd |
||
3742 | clevermous | 506 | mov ecx, [eax+PARTITION.FSUserFunctions] |
507 | call dword [ecx] |
||
2288 | clevermous | 508 | dec edi |
509 | jnz .freeloop |
||
510 | .nofree: |
||
511 | pop edi esi |
||
512 | ; 3b. Free the cache. |
||
513 | call disk_free_cache |
||
514 | ; 3c. Call the driver. |
||
515 | mov al, DISKFUNC.closemedia |
||
516 | stdcall disk_call_driver |
||
517 | ; 3d. Clear the flag. |
||
518 | mov [esi+DISK.MediaUsed], 0 |
||
519 | .nothing: |
||
520 | ret |
||
521 | |||
522 | ; This function is called by the driver and informs the kernel that the media |
||
523 | ; has changed. If the media is non-removable, it is called exactly once |
||
524 | ; immediately after 'disk_add' and once from 'disk_del'. |
||
525 | ; Parameters: |
||
526 | ; [esp+4] = handle of the disk, i.e. the pointer to the DISK structure. |
||
527 | ; [esp+8] = new status of the media: zero = no media, nonzero = media inserted. |
||
528 | disk_media_changed: |
||
529 | push ebx esi edi ; save used registers to be stdcall |
||
530 | ; 1. Remove the existing media, if it is present. |
||
531 | mov esi, [esp+4+12] ; esi = pointer to DISK |
||
532 | ; 1a. Check whether it is present. Since DISK.MediaInserted is changed only |
||
533 | ; in this function and calls to this function are synchronized, no lock is |
||
534 | ; required for checking. |
||
535 | cmp [esi+DISK.MediaInserted], 0 |
||
536 | jz .noremove |
||
537 | ; We really need to remove the media. |
||
538 | ; 1b. Acquire mutex. |
||
539 | lea ecx, [esi+DISK.MediaLock] |
||
540 | call mutex_lock |
||
541 | ; 1c. Clear the flag. |
||
542 | mov [esi+DISK.MediaInserted], 0 |
||
543 | ; 1d. Release mutex. |
||
544 | call mutex_unlock |
||
545 | ; 1e. Remove the "lifetime" reference and possibly destroy the structure. |
||
546 | call disk_media_dereference |
||
547 | .noremove: |
||
548 | ; 2. Test whether there is new media. |
||
549 | cmp dword [esp+8+12], 0 |
||
550 | jz .noinsert |
||
551 | ; Yep, there is. |
||
552 | ; 3. Process the new media. We assume that all media fields are available to |
||
553 | ; use, see comments in 'disk_media_dereference' (this covers using by previous |
||
554 | ; media referencers) and note that calls to this function are synchronized |
||
555 | ; (this covers using by new media referencers). |
||
556 | ; 3a. Call the 'querymedia' callback. |
||
557 | ; .Flags are set to zero for possible future extensions. |
||
558 | lea edx, [esi+DISK.MediaInfo] |
||
559 | and [edx+DISKMEDIAINFO.Flags], 0 |
||
560 | mov al, DISKFUNC.querymedia |
||
561 | stdcall disk_call_driver, edx |
||
562 | ; 3b. Check the result of the callback. Abort if it failed. |
||
563 | test eax, eax |
||
564 | jnz .noinsert |
||
565 | ; 3c. Allocate the cache unless disabled by the driver. Abort if failed. |
||
566 | call disk_init_cache |
||
567 | test al, al |
||
568 | jz .noinsert |
||
569 | ; 3d. Acquire the lifetime reference for the media object. |
||
570 | inc [esi+DISK.MediaRefCount] |
||
571 | ; 3e. Scan for partitions. Ignore result; the list of partitions is valid even |
||
572 | ; on errors. |
||
573 | call disk_scan_partitions |
||
574 | ; 3f. Media is inserted and available for use. |
||
575 | inc [esi+DISK.MediaInserted] |
||
576 | .noinsert: |
||
577 | ; 4. Return. |
||
578 | pop edi esi ebx ; restore used registers to be stdcall |
||
579 | ret 8 ; purge 2 dword arguments to be stdcall |
||
580 | |||
581 | ; This function is a thunk for all functions of a disk driver. |
||
582 | ; It checks whether the referenced function is implemented in the driver. |
||
583 | ; If so, this function jumps to the function in the driver. |
||
584 | ; Otherwise, it jumps to the default implementation. |
||
585 | ; al = offset of function in the DISKFUNC structure; |
||
586 | ; esi = pointer to the DISK structure; |
||
587 | ; stack is the same as for the corresponding function except that the |
||
588 | ; first parameter (void* userdata) is prepended automatically. |
||
589 | disk_call_driver: |
||
590 | movzx eax, al ; eax = offset of function in the DISKFUNC structure |
||
591 | ; 1. Prepend the first argument to the stack. |
||
592 | pop ecx ; ecx = return address |
||
593 | push [esi+DISK.UserData] ; add argument |
||
594 | push ecx ; save return address |
||
595 | ; 2. Check that the required function is inside the table. If not, go to 5. |
||
596 | mov ecx, [esi+DISK.Functions] |
||
597 | cmp eax, [ecx+DISKFUNC.strucsize] |
||
598 | jae .default |
||
599 | ; 3. Check that the required function is implemented. If not, go to 5. |
||
600 | mov ecx, [ecx+eax] |
||
601 | test ecx, ecx |
||
602 | jz .default |
||
603 | ; 4. Jump to the required function. |
||
604 | jmp ecx |
||
605 | .default: |
||
606 | ; 5. Driver does not implement the required function; use default implementation. |
||
607 | jmp dword [disk_default_callbacks+eax-4] |
||
608 | |||
609 | ; The default implementation of DISKFUNC.querymedia. |
||
610 | disk_default_querymedia: |
||
3598 | clevermous | 611 | movi eax, DISK_STATUS_INVALID_CALL |
2288 | clevermous | 612 | ret 8 |
613 | |||
614 | ; The default implementation of DISKFUNC.read and DISKFUNC.write. |
||
615 | disk_default_read: |
||
616 | disk_default_write: |
||
3598 | clevermous | 617 | movi eax, DISK_STATUS_INVALID_CALL |
2288 | clevermous | 618 | ret 20 |
619 | |||
620 | ; The default implementation of DISKFUNC.close, DISKFUNC.closemedia and |
||
621 | ; DISKFUNC.flush. |
||
622 | disk_default_close: |
||
623 | disk_default_closemedia: |
||
624 | disk_default_flush: |
||
625 | xor eax, eax |
||
626 | ret 4 |
||
627 | |||
628 | ; The default implementation of DISKFUNC.adjust_cache_size. |
||
629 | disk_default_adjust_cache_size: |
||
3164 | clevermous | 630 | mov eax, [esp+8] |
631 | ret 8 |
||
2288 | clevermous | 632 | |
633 | ; This is an internal function called from 'disk_media_changed' when a new media |
||
634 | ; is detected. It creates the list of partitions for the media. |
||
635 | ; If media is not partitioned, then the list consists of one partition which |
||
636 | ; covers all the media. |
||
637 | ; esi = pointer to the DISK structure. |
||
638 | disk_scan_partitions: |
||
639 | ; 1. Initialize .NumPartitions and .Partitions fields as zeros: empty list. |
||
640 | and [esi+DISK.NumPartitions], 0 |
||
641 | and [esi+DISK.Partitions], 0 |
||
5089 | clevermous | 642 | ; 2. Acquire the buffer for MBR and bootsector tests. See the comment before |
2288 | clevermous | 643 | ; the 'partition_buffer_users' variable. |
5089 | clevermous | 644 | mov eax, [esi+DISK.MediaInfo.SectorSize] |
645 | cmp eax, 512 |
||
646 | jnz @f |
||
2288 | clevermous | 647 | mov ebx, mbr_buffer ; assume the global buffer is free |
648 | lock inc [partition_buffer_users] |
||
649 | jz .buffer_acquired ; yes, it is free |
||
650 | lock dec [partition_buffer_users] ; no, we must allocate |
||
5089 | clevermous | 651 | @@: |
652 | lea eax, [eax*3] |
||
653 | stdcall kernel_alloc, eax |
||
2288 | clevermous | 654 | test eax, eax |
655 | jz .nothing |
||
656 | xchg eax, ebx |
||
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. |
||
5089 | clevermous | 660 | ; 3. Prepare things for the loop. |
2288 | clevermous | 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. |
||
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 |
||
5089 | clevermous | 669 | ; 4. MBR is 512 bytes long. If sector size is less than 512 bytes, |
670 | ; assume no MBR, no partitions and go to 10. |
||
671 | cmp [esi+DISK.MediaInfo.SectorSize], 512 |
||
672 | jb .notmbr |
||
2288 | clevermous | 673 | .new_mbr: |
674 | ; 5. Read the current sector. |
||
675 | ; Note that 'read' callback operates with 64-bit sector numbers, so we must |
||
676 | ; push additional zero as a high dword of sector number. |
||
677 | mov al, DISKFUNC.read |
||
678 | push 1 |
||
679 | stdcall disk_call_driver, ebx, ebp, 0, esp |
||
680 | pop ecx |
||
681 | ; 6. If the read has failed, abort the loop. |
||
682 | dec ecx |
||
683 | jnz .mbr_failed |
||
684 | ; 7. Check the MBR/EBR signature. If it is wrong, abort the loop. |
||
685 | ; Soon we will access the partition table which starts at ebx+0x1BE, |
||
686 | ; so we can fill its address right now. If we do it now, then the addressing |
||
687 | ; [ecx+0x40] is shorter than [ebx+0x1fe]: one-byte offset vs 4-bytes offset. |
||
688 | lea ecx, [ebx+0x1be] ; ecx -> partition table |
||
689 | cmp word [ecx+0x40], 0xaa55 |
||
690 | jnz .mbr_failed |
||
691 | ; 8. The MBR is treated differently from EBRs. For MBR we additionally need to |
||
692 | ; execute step 9 and possibly step 10. |
||
693 | test ebp, ebp |
||
694 | jnz .mbr |
||
695 | ; The partition table can be present or not present. In the first case, we just |
||
696 | ; read the MBR. In the second case, we just read the bootsector for a |
||
697 | ; filesystem. |
||
698 | ; The following algorithm is used to distinguish between these cases. |
||
699 | ; A. If at least one entry of the partition table is invalid, this is |
||
700 | ; a bootsector. See the description of 'is_partition_table_entry' for |
||
701 | ; definition of validity. |
||
702 | ; B. If all entries are empty (filesystem type field is zero) and the first |
||
703 | ; byte is jmp opcode (0EBh or 0E9h), this is a bootsector which happens to |
||
704 | ; have zeros in the place of partition table. |
||
705 | ; C. Otherwise, this is an MBR. |
||
706 | ; 9. Test for MBR vs bootsector. |
||
707 | ; 9a. Check entries. If any is invalid, go to 10 (rule A). |
||
708 | call is_partition_table_entry |
||
709 | jc .notmbr |
||
710 | add ecx, 10h |
||
711 | call is_partition_table_entry |
||
712 | jc .notmbr |
||
713 | add ecx, 10h |
||
714 | call is_partition_table_entry |
||
715 | jc .notmbr |
||
716 | add ecx, 10h |
||
717 | call is_partition_table_entry |
||
718 | jc .notmbr |
||
719 | ; 9b. Check types of the entries. If at least one is nonzero, go to 11 (rule C). |
||
720 | mov al, [ecx-30h+PARTITION_TABLE_ENTRY.Type] |
||
721 | or al, [ecx-20h+PARTITION_TABLE_ENTRY.Type] |
||
722 | or al, [ecx-10h+PARTITION_TABLE_ENTRY.Type] |
||
723 | or al, [ecx+PARTITION_TABLE_ENTRY.Type] |
||
724 | jnz .mbr |
||
725 | ; 9c. Empty partition table or bootsector with many zeroes? (rule B) |
||
726 | cmp byte [ebx], 0EBh |
||
727 | jz .notmbr |
||
728 | cmp byte [ebx], 0E9h |
||
729 | jnz .mbr |
||
730 | .notmbr: |
||
731 | ; 10. This is not an MBR. The media is not partitioned. Create one partition |
||
732 | ; which covers all the media and abort the loop. |
||
733 | stdcall disk_add_partition, 0, 0, \ |
||
3742 | clevermous | 734 | dword [esi+DISK.MediaInfo.Capacity], dword [esi+DISK.MediaInfo.Capacity+4], esi |
2288 | clevermous | 735 | jmp .done |
736 | .mbr: |
||
737 | ; 11. Process all entries of the new MBR/EBR |
||
738 | lea ecx, [ebx+0x1be] ; ecx -> partition table |
||
739 | push 0 ; assume no extended partition |
||
740 | call process_partition_table_entry |
||
741 | add ecx, 10h |
||
742 | call process_partition_table_entry |
||
743 | add ecx, 10h |
||
744 | call process_partition_table_entry |
||
745 | add ecx, 10h |
||
746 | call process_partition_table_entry |
||
747 | pop ebp |
||
748 | ; 12. Test whether we found a new EBR and should continue the loop. |
||
749 | ; 12a. If there was no next EBR, return. |
||
750 | test ebp, ebp |
||
751 | jz .done |
||
752 | ; Ok, we have EBR. |
||
753 | ; 12b. EBRs addresses are relative to the start of extended partition. |
||
754 | ; For simplicity, just abort if an 32-bit overflow occurs; large disks |
||
755 | ; are most likely partitioned with GPT, not MBR scheme, since the precise |
||
756 | ; calculation here would increase limit just twice at the price of big |
||
757 | ; compatibility problems. |
||
758 | pop eax ; load extended partition |
||
759 | add ebp, eax |
||
760 | jc .mbr_failed |
||
761 | ; 12c. If extended partition has not yet started, start it. |
||
762 | test eax, eax |
||
763 | jnz @f |
||
764 | mov eax, ebp |
||
765 | @@: |
||
766 | ; 12c. If the limit is not exceeded, continue the loop. |
||
767 | dec dword [esp] |
||
768 | push eax ; store extended partition |
||
769 | jnz .new_mbr |
||
770 | .mbr_failed: |
||
771 | .done: |
||
772 | ; 13. Cleanup after the loop. |
||
773 | pop eax ; not important anymore |
||
774 | pop eax ; not important anymore |
||
775 | pop ebp ; restore ebp |
||
776 | ; 14. Release the buffer. |
||
777 | ; 14a. Test whether it is the global buffer or we have allocated it. |
||
778 | cmp ebx, mbr_buffer |
||
779 | jz .release_partition_buffer |
||
780 | ; 14b. If we have allocated it, free it. |
||
781 | xchg eax, ebx |
||
782 | call free |
||
783 | jmp .nothing |
||
784 | ; 14c. Otherwise, release reference. |
||
785 | .release_partition_buffer: |
||
786 | lock dec [partition_buffer_users] |
||
787 | .nothing: |
||
788 | ; 15. Return. |
||
789 | ret |
||
790 | |||
791 | ; This is an internal function called from disk_scan_partitions. It checks |
||
792 | ; whether the entry pointed to by ecx is a valid entry of partition table. |
||
793 | ; The entry is valid if the first byte is 0 or 80h, the first sector plus the |
||
794 | ; length is less than twice the size of media. Multiplication by two is |
||
795 | ; required since the size mentioned in the partition table can be slightly |
||
796 | ; greater than the real size. |
||
797 | is_partition_table_entry: |
||
798 | ; 1. Check .Bootable field. |
||
799 | mov al, [ecx+PARTITION_TABLE_ENTRY.Bootable] |
||
800 | and al, 7Fh |
||
801 | jnz .invalid |
||
802 | ; 3. Calculate first sector + length. Note that .FirstAbsSector is relative |
||
803 | ; to the MBR/EBR, so the real sum is ebp + .FirstAbsSector + .Length. |
||
804 | mov eax, ebp |
||
805 | xor edx, edx |
||
806 | add eax, [ecx+PARTITION_TABLE_ENTRY.FirstAbsSector] |
||
807 | adc edx, 0 |
||
808 | add eax, [ecx+PARTITION_TABLE_ENTRY.Length] |
||
809 | adc edx, 0 |
||
810 | ; 4. Divide by two. |
||
811 | shr edx, 1 |
||
812 | rcr eax, 1 |
||
813 | ; 5. Compare with capacity. If the subtraction (edx:eax) - .Capacity does not |
||
814 | ; overflow, this is bad. |
||
815 | sub eax, dword [esi+DISK.MediaInfo.Capacity] |
||
816 | sbb edx, dword [esi+DISK.MediaInfo.Capacity+4] |
||
817 | jnc .invalid |
||
818 | .valid: |
||
819 | ; 5. Return success: CF is cleared. |
||
820 | clc |
||
821 | ret |
||
822 | .invalid: |
||
823 | ; 6. Return fail: CF is set. |
||
824 | stc |
||
825 | ret |
||
826 | |||
827 | ; This is an internal function called from disk_scan_partitions. It processes |
||
828 | ; the entry pointed to by ecx. |
||
829 | ; * If the entry is invalid, just ignore this entry. |
||
830 | ; * If the type is zero, just ignore this entry. |
||
831 | ; * If the type is one of types for extended partition, store the address |
||
832 | ; of this partition as the new MBR in [esp+4]. |
||
833 | ; * Otherwise, add the partition to the list of partitions for this disk. |
||
834 | ; We don't use the type from the entry to identify the file system; |
||
835 | ; fs-specific checks do this more reliably. |
||
836 | process_partition_table_entry: |
||
837 | ; 1. Check for valid entry. If invalid, return (go to 5). |
||
838 | call is_partition_table_entry |
||
839 | jc .nothing |
||
840 | ; 2. Check for empty entry. If invalid, return (go to 5). |
||
841 | mov al, [ecx+PARTITION_TABLE_ENTRY.Type] |
||
842 | test al, al |
||
843 | jz .nothing |
||
844 | ; 3. Check for extended partition. If extended, go to 6. |
||
845 | irp type,\ |
||
846 | 0x05,\ ; DOS: extended partition |
||
847 | 0x0f,\ ; WIN95: extended partition, LBA-mapped |
||
848 | 0xc5,\ ; DRDOS/secured: extended partition |
||
849 | 0xd5 ; Old Multiuser DOS secured: extended partition |
||
850 | { |
||
851 | cmp al, type |
||
852 | jz .extended |
||
853 | } |
||
854 | ; 4. If we are here, that is a normal partition. Add it to the list. |
||
855 | ; Note that the first sector is relative to MBR/EBR. |
||
856 | mov eax, ebp |
||
857 | xor edx, edx |
||
858 | add eax, [ecx+PARTITION_TABLE_ENTRY.FirstAbsSector] |
||
859 | adc edx, 0 |
||
860 | push ecx |
||
861 | stdcall disk_add_partition, eax, edx, \ |
||
3742 | clevermous | 862 | [ecx+PARTITION_TABLE_ENTRY.Length], 0, esi |
2288 | clevermous | 863 | pop ecx |
864 | .nothing: |
||
865 | ; 5. Return. |
||
866 | ret |
||
867 | .extended: |
||
868 | ; 6. If we are here, that is an extended partition. Store the address. |
||
869 | mov eax, [ecx+PARTITION_TABLE_ENTRY.FirstAbsSector] |
||
870 | mov [esp+4], eax |
||
871 | ret |
||
872 | |||
873 | ; This is an internal function called from disk_scan_partitions and |
||
874 | ; process_partition_table_entry. It adds one partition to the list of |
||
875 | ; partitions for the media. |
||
3742 | clevermous | 876 | ; Important note: start, length, disk MUST be present and |
877 | ; MUST be in the same order as in PARTITION structure. |
||
878 | ; esi duplicates [disk]. |
||
879 | proc disk_add_partition stdcall uses ebx edi, start:qword, length:qword, disk:dword |
||
2288 | clevermous | 880 | ; 1. Check that this partition will not exceed the limit on total number. |
881 | cmp [esi+DISK.NumPartitions], MAX_NUM_PARTITIONS |
||
882 | jae .nothing |
||
883 | ; 2. Check that this partition does not overlap with any already registered |
||
884 | ; partition. Since any file system assumes that the disk data will not change |
||
885 | ; outside of its control, such overlap could be destructive. |
||
886 | ; Since the number of partitions is usually very small and is guaranteed not |
||
887 | ; to be large, the simple linear search is sufficient. |
||
888 | ; 2a. Prepare the loop: edi will point to the current item of .Partitions |
||
889 | ; array, ecx will be the current item, ebx will hold number of items left. |
||
890 | mov edi, [esi+DISK.Partitions] |
||
891 | mov ebx, [esi+DISK.NumPartitions] |
||
892 | test ebx, ebx |
||
893 | jz .partitionok |
||
894 | .scan_existing: |
||
895 | ; 2b. Get the next partition. |
||
896 | mov ecx, [edi] |
||
897 | add edi, 4 |
||
898 | ; The range [.FirstSector, .FirstSector+.Length) must be either entirely to |
||
899 | ; the left of [start, start+length) or entirely to the right. |
||
900 | ; 2c. Subtract .FirstSector - start. The possible overflow distinguish between |
||
901 | ; cases "to the left" (2e) and "to the right" (2d). |
||
902 | mov eax, dword [ecx+PARTITION.FirstSector] |
||
903 | mov edx, dword [ecx+PARTITION.FirstSector+4] |
||
904 | sub eax, dword [start] |
||
905 | sbb edx, dword [start+4] |
||
906 | jb .less |
||
907 | ; 2d. .FirstSector is greater than or equal to start. Check that .FirstSector |
||
908 | ; is greater than or equal to start+length; the subtraction |
||
909 | ; (.FirstSector-start) - length must not cause overflow. Go to 2g if life is |
||
910 | ; good or to 2f in the other case. |
||
911 | sub eax, dword [length] |
||
912 | sbb edx, dword [length+4] |
||
913 | jb .overlap |
||
914 | jmp .next_existing |
||
915 | .less: |
||
916 | ; 2e. .FirstSector is less than start. Check that .FirstSector+.Length is less |
||
917 | ; than or equal to start. If the addition (.FirstSector-start) + .Length does |
||
918 | ; not cause overflow, then .FirstSector + .Length is strictly less than start; |
||
919 | ; since the equality is also valid, use decrement preliminarily. Go to 2g or |
||
920 | ; 2f depending on the overflow. |
||
921 | sub eax, 1 |
||
922 | sbb edx, 0 |
||
923 | add eax, dword [ecx+PARTITION.Length] |
||
924 | adc edx, dword [ecx+PARTITION.Length+4] |
||
925 | jnc .next_existing |
||
926 | .overlap: |
||
927 | ; 2f. The partition overlaps with previously registered partition. Say warning |
||
928 | ; and return with nothing done. |
||
929 | dbgstr 'two partitions overlap, ignoring the last one' |
||
930 | jmp .nothing |
||
931 | .next_existing: |
||
932 | ; 2g. The partition does not overlap with the current partition. Continue the |
||
933 | ; loop. |
||
934 | dec ebx |
||
935 | jnz .scan_existing |
||
936 | .partitionok: |
||
937 | ; 3. The partition has passed tests. Reallocate the partitions array for a new |
||
938 | ; entry. |
||
939 | ; 3a. Call the allocator. |
||
940 | mov eax, [esi+DISK.NumPartitions] |
||
941 | inc eax ; one more entry |
||
942 | shl eax, 2 ; each entry is dword |
||
943 | call malloc |
||
944 | ; 3b. Test the result. If failed, return with nothing done. |
||
945 | test eax, eax |
||
946 | jz .nothing |
||
947 | ; 3c. Copy the old array to the new array. |
||
948 | mov edi, eax |
||
949 | push esi |
||
950 | mov ecx, [esi+DISK.NumPartitions] |
||
951 | mov esi, [esi+DISK.Partitions] |
||
952 | rep movsd |
||
953 | pop esi |
||
954 | ; 3d. Set the field in the DISK structure to the new array. |
||
955 | xchg [esi+DISK.Partitions], eax |
||
956 | ; 3e. Free the old array. |
||
957 | call free |
||
958 | ; 4. Recognize the file system. |
||
959 | ; 4a. Call the filesystem recognizer. It will allocate the PARTITION structure |
||
960 | ; with possible filesystem-specific fields. |
||
961 | call disk_detect_partition |
||
962 | ; 4b. Check return value. If zero, return with list not changed; so far only |
||
963 | ; the array was reallocated, this is ok for other code. |
||
964 | test eax, eax |
||
965 | jz .nothing |
||
966 | ; 5. Insert the new partition to the list. |
||
967 | stosd |
||
968 | inc [esi+DISK.NumPartitions] |
||
969 | ; 6. Return. |
||
970 | .nothing: |
||
971 | ret |
||
972 | endp |
||
973 | |||
974 | ; This is an internal function called from disk_add_partition. |
||
975 | ; It tries to recognize the file system on the partition and allocates the |
||
976 | ; corresponding PARTITION structure with filesystem-specific fields. |
||
977 | disk_detect_partition: |
||
978 | ; This function inherits the stack frame from disk_add_partition. In stdcall |
||
979 | ; with ebp-based frame arguments start from ebp+8, since [ebp]=saved ebp |
||
980 | ; and [ebp+4]=return address. |
||
981 | virtual at ebp+8 |
||
982 | .start dq ? |
||
983 | .length dq ? |
||
3742 | clevermous | 984 | .disk dd ? |
2288 | clevermous | 985 | end virtual |
3742 | clevermous | 986 | ; 1. Read the bootsector to the buffer. |
2643 | clevermous | 987 | ; When disk_add_partition is called, ebx contains a pointer to |
3742 | clevermous | 988 | ; a three-sectors-sized buffer. This function saves ebx in the stack |
2643 | clevermous | 989 | ; immediately before ebp. |
3742 | clevermous | 990 | mov ebx, [ebp-4] ; get buffer |
5089 | clevermous | 991 | add ebx, [esi+DISK.MediaInfo.SectorSize] ; advance over MBR data to bootsector data |
3742 | clevermous | 992 | add ebp, 8 ; ebp points to part of PARTITION structure |
993 | xor eax, eax ; first sector of the partition |
||
994 | call fs_read32_sys |
||
995 | push eax |
||
2643 | clevermous | 996 | ; 2. Run tests for all supported filesystems. If at least one test succeeded, |
997 | ; go to 4. |
||
3742 | clevermous | 998 | ; For tests: |
999 | ; ebp -> first three fields of PARTITION structure, .start, .length, .disk; |
||
1000 | ; [esp] = error code after bootsector read: 0 = ok, otherwise = failed, |
||
1001 | ; ebx points to the buffer for bootsector, |
||
5089 | clevermous | 1002 | ; ebx+[esi+DISK.MediaInfo.SectorSize] points to sector-sized buffer that can be used for anything. |
2643 | clevermous | 1003 | call fat_create_partition |
1004 | test eax, eax |
||
1005 | jnz .success |
||
3742 | clevermous | 1006 | call ntfs_create_partition |
1007 | test eax, eax |
||
1008 | jnz .success |
||
1009 | call ext2_create_partition |
||
1010 | test eax, eax |
||
1011 | jnz .success |
||
3913 | dunkaist | 1012 | call xfs_create_partition |
1013 | test eax, eax |
||
1014 | jnz .success |
||
2643 | clevermous | 1015 | ; 3. No file system has recognized the volume, so just allocate the PARTITION |
2288 | clevermous | 1016 | ; structure without extra fields. |
3598 | clevermous | 1017 | movi eax, sizeof.PARTITION |
2288 | clevermous | 1018 | call malloc |
1019 | test eax, eax |
||
1020 | jz .nothing |
||
3742 | clevermous | 1021 | mov edx, dword [ebp+PARTITION.FirstSector] |
2288 | clevermous | 1022 | mov dword [eax+PARTITION.FirstSector], edx |
3742 | clevermous | 1023 | mov edx, dword [ebp+PARTITION.FirstSector+4] |
2288 | clevermous | 1024 | mov dword [eax+PARTITION.FirstSector+4], edx |
3742 | clevermous | 1025 | mov edx, dword [ebp+PARTITION.Length] |
2288 | clevermous | 1026 | mov dword [eax+PARTITION.Length], edx |
3742 | clevermous | 1027 | mov edx, dword [ebp+PARTITION.Length+4] |
2288 | clevermous | 1028 | mov dword [eax+PARTITION.Length+4], edx |
2643 | clevermous | 1029 | mov [eax+PARTITION.Disk], esi |
3742 | clevermous | 1030 | mov [eax+PARTITION.FSUserFunctions], default_fs_functions |
2643 | clevermous | 1031 | .success: |
2288 | clevermous | 1032 | .nothing: |
3742 | clevermous | 1033 | sub ebp, 8 ; restore ebp |
2643 | clevermous | 1034 | ; 4. Return with eax = pointer to PARTITION or NULL. |
1035 | pop ecx |
||
2288 | clevermous | 1036 | ret |
1037 | |||
3742 | clevermous | 1038 | iglobal |
1039 | align 4 |
||
1040 | default_fs_functions: |
||
1041 | dd free |
||
1042 | dd 0 ; no user functions |
||
1043 | endg |
||
1044 | |||
2288 | clevermous | 1045 | ; This function is called from file_system_lfn. |
1046 | ; This handler gets the control each time when fn 70 is called |
||
1047 | ; with unknown item of root subdirectory. |
||
6468 | pathoswith | 1048 | ; in: esi = ebp -> path string |
2288 | clevermous | 1049 | ; out: if the handler processes path, it must not return in file_system_lfn, |
1050 | ; but instead pop return address and return directly to the caller |
||
1051 | ; otherwise simply return |
||
1052 | dyndisk_handler: |
||
1053 | push ebx edi ; save registers used in file_system_lfn |
||
1054 | ; 1. Acquire the mutex. |
||
1055 | mov ecx, disk_list_mutex |
||
1056 | call mutex_lock |
||
1057 | ; 2. Loop over the list of DISK structures. |
||
1058 | ; 2a. Initialize. |
||
1059 | mov ebx, disk_list |
||
1060 | .scan: |
||
1061 | ; 2b. Get the next item. |
||
1062 | mov ebx, [ebx+DISK.Next] |
||
1063 | ; 2c. Check whether the list is done. If so, go to 3. |
||
1064 | cmp ebx, disk_list |
||
1065 | jz .notfound |
||
1066 | ; 2d. Compare names. If names match, go to 5. |
||
1067 | mov edi, [ebx+DISK.Name] |
||
1068 | push esi |
||
1069 | @@: |
||
1070 | ; esi points to the name from fs operation; it is terminated by zero or slash. |
||
1071 | lodsb |
||
1072 | test al, al |
||
1073 | jz .eoin_dec |
||
1074 | cmp al, '/' |
||
1075 | jz .eoin |
||
1076 | ; edi points to the disk name. |
||
1077 | inc edi |
||
1078 | ; edi points to lowercase name, this is a requirement for the driver. |
||
1079 | ; Characters at esi can have any register. Lowercase the current character. |
||
1080 | ; This lowercasing works for latin letters and digits; since the disk name |
||
1081 | ; should not contain other symbols, this is ok. |
||
1082 | or al, 20h |
||
1083 | cmp al, [edi-1] |
||
1084 | jz @b |
||
1085 | .wrongname: |
||
1086 | ; 2f. Names don't match. Continue the loop. |
||
1087 | pop esi |
||
1088 | jmp .scan |
||
1089 | .notfound: |
||
1090 | ; The loop is done and no name matches. |
||
1091 | ; 3. Release the mutex. |
||
1092 | call mutex_unlock |
||
1093 | ; 4. Return normally. |
||
1094 | pop edi ebx ; restore registers used in file_system_lfn |
||
1095 | ret |
||
1096 | ; part of 2d: the name matches partially, but we must check that this is full |
||
1097 | ; equality. |
||
1098 | .eoin_dec: |
||
1099 | dec esi |
||
1100 | .eoin: |
||
1101 | cmp byte [edi], 0 |
||
1102 | jnz .wrongname |
||
1103 | ; We found the addressed DISK structure. |
||
1104 | ; 5. Reference the disk. |
||
1105 | lock inc [ebx+DISK.RefCount] |
||
1106 | ; 6. Now we are sure that the DISK structure is not going to die at least |
||
1107 | ; while we are working with it, so release the global mutex. |
||
1108 | call mutex_unlock |
||
2643 | clevermous | 1109 | pop ecx ; pop from the stack saved value of esi |
2288 | clevermous | 1110 | ; 7. Acquire the mutex for media object. |
1111 | pop edi ; restore edi |
||
1112 | lea ecx, [ebx+DISK.MediaLock] |
||
1113 | call mutex_lock |
||
1114 | ; 8. Get the media object. If it is not NULL, reference it. |
||
1115 | xor edx, edx |
||
1116 | cmp [ebx+DISK.MediaInserted], dl |
||
1117 | jz @f |
||
1118 | mov edx, ebx |
||
1119 | inc [ebx+DISK.MediaRefCount] |
||
1120 | @@: |
||
1121 | ; 9. Now we are sure that the media object, if it exists, is not going to die |
||
1122 | ; at least while we are working with it, so release the mutex for media object. |
||
1123 | call mutex_unlock |
||
1124 | mov ecx, ebx |
||
1125 | pop ebx eax ; restore ebx, pop return address |
||
1126 | ; 10. Check whether the fs operation wants to enumerate partitions (go to 11) |
||
1127 | ; or work with some concrete partition (go to 12). |
||
1128 | cmp byte [esi], 0 |
||
1129 | jnz .haspartition |
||
1130 | ; 11. The fs operation wants to enumerate partitions. |
||
1131 | ; 11a. Only "list directory" operation is applicable to / |
||
1132 | ; the operation code. If wrong, go to 13. |
||
1133 | cmp dword [ebx], 1 |
||
1134 | jnz .access_denied |
||
1135 | ; 11b. If the media is inserted, use 'fs_dyndisk_next' as an enumeration |
||
1136 | ; procedure. Otherwise, use 'fs_dyndisk_next_nomedia'. |
||
1137 | mov esi, fs_dyndisk_next_nomedia |
||
1138 | test edx, edx |
||
1139 | jz @f |
||
1140 | mov esi, fs_dyndisk_next |
||
1141 | @@: |
||
1142 | ; 11c. Let the procedure from fs_lfn.inc do the job. |
||
1143 | jmp file_system_lfn.maindir_noesi |
||
6468 | pathoswith | 1144 | |
1145 | .access_denied: |
||
1146 | mov dword [esp+32], ERROR_ACCESS_DENIED |
||
1147 | mov esi, ecx ; disk*dereference assume that esi points to DISK |
||
1148 | .cleanup_esi: |
||
1149 | test edx, edx ; if there are no media, we didn't reference it |
||
1150 | jz @f |
||
1151 | call disk_media_dereference |
||
1152 | @@: |
||
1153 | call disk_dereference |
||
1154 | stdcall kernel_free, ebp |
||
1155 | ret |
||
1156 | |||
1157 | .dyndisk_cleanup: |
||
1158 | pop esi |
||
1159 | pop edx |
||
1160 | mov dword [esp+32], ERROR_FILE_NOT_FOUND |
||
1161 | jmp .cleanup_esi |
||
1162 | |||
2288 | clevermous | 1163 | .haspartition: |
1164 | ; 12. The fs operation has specified some partition. |
||
1165 | push edx |
||
1166 | push ecx |
||
6464 | pathoswith | 1167 | xor eax, eax |
1168 | lodsb |
||
1169 | sub eax, '0' |
||
1170 | jz .dyndisk_cleanup |
||
1171 | cmp eax, 10 |
||
1172 | jnc .dyndisk_cleanup |
||
1173 | mov ecx, eax |
||
1174 | lodsb |
||
1175 | cmp eax, '/' |
||
1176 | jz @f |
||
1177 | test eax, eax |
||
1178 | jnz .dyndisk_cleanup |
||
1179 | dec esi |
||
1180 | @@: |
||
2288 | clevermous | 1181 | dec ecx ; convert to zero-based partition index |
6464 | pathoswith | 1182 | pop edx ; edx = pointer to DISK, dword [esp] = NULL or edx |
4273 | clevermous | 1183 | ; If the driver does not support insert notifications and we are the only fs |
1184 | ; operation with this disk, ask the driver whether the media |
||
1185 | ; was inserted/removed/changed. Otherwise, assume that media status is valid. |
||
1186 | test byte [edx+DISK.DriverFlags], DISK_NO_INSERT_NOTIFICATION |
||
1187 | jz .media_accurate |
||
1188 | push ecx esi |
||
1189 | mov esi, edx |
||
1190 | cmp dword [esp+8], 0 |
||
1191 | jz .test_no_media |
||
1192 | cmp [esi+DISK.MediaRefCount], 2 |
||
1193 | jnz .media_accurate_pop |
||
1194 | lea edx, [esi+DISK.MediaInfo] |
||
1195 | and [edx+DISKMEDIAINFO.Flags], 0 |
||
1196 | mov al, DISKFUNC.querymedia |
||
1197 | stdcall disk_call_driver, edx |
||
2288 | clevermous | 1198 | test eax, eax |
4273 | clevermous | 1199 | jz .media_accurate_pop |
1200 | stdcall disk_media_dereference ; drop our reference so that disk_media_changed could close the media |
||
1201 | stdcall disk_media_changed, esi, 0 |
||
1202 | and dword [esp+8], 0 ; no media |
||
1203 | .test_no_media: |
||
1204 | stdcall disk_media_changed, esi, 1 ; issue fake notification |
||
6468 | pathoswith | 1205 | ; if querymedia() inside disk_media_changed returns error, the notification is ignored |
4273 | clevermous | 1206 | cmp [esi+DISK.MediaInserted], 0 |
1207 | jz .media_accurate_pop |
||
1208 | lock inc [esi+DISK.MediaRefCount] |
||
1209 | mov dword [esp+8], esi |
||
1210 | .media_accurate_pop: |
||
1211 | mov edx, esi |
||
1212 | pop esi ecx |
||
1213 | .media_accurate: |
||
1214 | pop eax |
||
1215 | test eax, eax |
||
2288 | clevermous | 1216 | jz .nomedia |
1217 | cmp ecx, [edx+DISK.NumPartitions] |
||
6468 | pathoswith | 1218 | jae .notfound2 |
2643 | clevermous | 1219 | mov eax, [edx+DISK.Partitions] |
1220 | mov eax, [eax+ecx*4] |
||
1221 | mov edi, [eax+PARTITION.FSUserFunctions] |
||
1222 | mov ecx, [ebx] |
||
3742 | clevermous | 1223 | cmp [edi+4], ecx |
2643 | clevermous | 1224 | jbe .unsupported |
1225 | push edx |
||
1226 | push ebp |
||
1227 | mov ebp, eax |
||
3742 | clevermous | 1228 | call dword [edi+8+ecx*4] |
2643 | clevermous | 1229 | pop ebp |
1230 | pop edx |
||
1231 | mov dword [esp+32], eax |
||
1232 | mov dword [esp+20], ebx |
||
2288 | clevermous | 1233 | .cleanup: |
1234 | mov esi, edx |
||
1235 | call disk_media_dereference |
||
6468 | pathoswith | 1236 | @@: |
2288 | clevermous | 1237 | call disk_dereference |
6468 | pathoswith | 1238 | stdcall kernel_free, ebp |
2288 | clevermous | 1239 | ret |
6468 | pathoswith | 1240 | |
1241 | .unsupported: |
||
2643 | clevermous | 1242 | mov dword [esp+32], ERROR_UNKNOWN_FS |
6468 | pathoswith | 1243 | cmp edi, default_fs_functions |
1244 | jz .cleanup |
||
1245 | mov dword [esp+32], ERROR_UNSUPPORTED_FS |
||
2643 | clevermous | 1246 | jmp .cleanup |
6468 | pathoswith | 1247 | |
1248 | .notfound2: |
||
2288 | clevermous | 1249 | mov dword [esp+32], ERROR_FILE_NOT_FOUND |
1250 | jmp .cleanup |
||
6468 | pathoswith | 1251 | |
2288 | clevermous | 1252 | .nomedia: |
1253 | test ecx, ecx |
||
6468 | pathoswith | 1254 | jnz .notfound2 |
2288 | clevermous | 1255 | mov dword [esp+32], ERROR_DEVICE |
1256 | mov esi, edx |
||
6468 | pathoswith | 1257 | jmp @b |
1258 | |||
1259 | ; This is a callback for enumerating partitions called from |
||
1260 | ; file_system_lfn.maindir in the case of inserted media. |
||
1261 | ; It just increments eax until DISK.NumPartitions reached and then |
||
1262 | ; cleans up. |
||
1263 | fs_dyndisk_next: |
||
1264 | mov ecx, [esp+8] |
||
1265 | cmp eax, [ecx+DISK.NumPartitions] |
||
1266 | jae .nomore |
||
1267 | inc eax |
||
1268 | clc |
||
1269 | ret |
||
1270 | .nomore: |
||
1271 | pusha |
||
1272 | mov esi, ecx |
||
1273 | call disk_media_dereference |
||
2288 | clevermous | 1274 | call disk_dereference |
6468 | pathoswith | 1275 | popa |
1276 | stc |
||
2288 | clevermous | 1277 | ret |
1278 | |||
6468 | pathoswith | 1279 | ; This is a callback for enumerating partitions called from |
1280 | ; file_system_lfn.maindir in the case of missing media. |
||
1281 | ; In this case we create one pseudo-partition. |
||
1282 | fs_dyndisk_next_nomedia: |
||
1283 | cmp eax, 1 |
||
1284 | jae .nomore |
||
1285 | inc eax |
||
1286 | clc |
||
1287 | ret |
||
1288 | .nomore: |
||
1289 | mov ecx, [esp+8] |
||
1290 | pusha |
||
1291 | mov esi, ecx |
||
1292 | call disk_dereference |
||
1293 | popa |
||
1294 | stc |
||
1295 | ret |
||
1296 | |||
2288 | clevermous | 1297 | ; This function is called from file_system_lfn. |
1298 | ; This handler is called when virtual root is enumerated |
||
1299 | ; and must return all items which can be handled by this. |
||
1300 | ; It is called several times, first time with eax=0 |
||
1301 | ; in: eax = 0 for first call, previously returned value for subsequent calls |
||
1302 | ; out: eax = 0 => no more items |
||
1303 | ; eax != 0 => buffer pointed to by edi contains name of item |
||
1304 | dyndisk_enum_root: |
||
1305 | push edx ; save register used in file_system_lfn |
||
1306 | mov ecx, disk_list_mutex ; it will be useful |
||
1307 | ; 1. If this is the first call, acquire the mutex and initialize. |
||
1308 | test eax, eax |
||
1309 | jnz .notfirst |
||
1310 | call mutex_lock |
||
1311 | mov eax, disk_list |
||
1312 | .notfirst: |
||
1313 | ; 2. Get next item. |
||
1314 | mov eax, [eax+DISK.Next] |
||
1315 | ; 3. If there are no more items, go to 6. |
||
1316 | cmp eax, disk_list |
||
1317 | jz .last |
||
1318 | ; 4. Copy name from the DISK structure to edi. |
||
1319 | push eax esi |
||
1320 | mov esi, [eax+DISK.Name] |
||
1321 | @@: |
||
1322 | lodsb |
||
1323 | stosb |
||
1324 | test al, al |
||
1325 | jnz @b |
||
1326 | pop esi eax |
||
1327 | ; 5. Return with eax = item. |
||
1328 | pop edx ; restore register used in file_system_lfn |
||
1329 | ret |
||
1330 | .last: |
||
1331 | ; 6. Release the mutex and return with eax = 0. |
||
1332 | call mutex_unlock |
||
1333 | xor eax, eax |
||
1334 | pop edx ; restore register used in file_system_lfn |
||
1335 | ret |