| /* |
| * Copyright (C) 1995, 1997 Wolfgang Solfrank |
| * Copyright (c) 1995 Martin Husemann |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| |
| #include <stdlib.h> |
| #include <string.h> |
| #include <stdio.h> |
| #include <unistd.h> |
| |
| #include "ext.h" |
| |
| int |
| readboot(int dosfs, struct bootblock *boot) |
| { |
| u_char block[DOSBOOTBLOCKSIZE]; |
| u_char fsinfo[2 * DOSBOOTBLOCKSIZE]; |
| u_char backup[DOSBOOTBLOCKSIZE]; |
| int ret = FSOK; |
| int i; |
| |
| if ((size_t)read(dosfs, block, sizeof block) != sizeof block) { |
| perr("could not read boot block"); |
| return FSFATAL; |
| } |
| |
| if (block[510] != 0x55 || block[511] != 0xaa) { |
| pfatal("Invalid signature in boot block: %02x%02x", |
| block[511], block[510]); |
| return FSFATAL; |
| } |
| |
| memset(boot, 0, sizeof *boot); |
| boot->ValidFat = -1; |
| |
| /* decode bios parameter block */ |
| boot->bpbBytesPerSec = block[11] + (block[12] << 8); |
| boot->bpbSecPerClust = block[13]; |
| boot->bpbResSectors = block[14] + (block[15] << 8); |
| boot->bpbFATs = block[16]; |
| boot->bpbRootDirEnts = block[17] + (block[18] << 8); |
| boot->bpbSectors = block[19] + (block[20] << 8); |
| boot->bpbMedia = block[21]; |
| boot->bpbFATsmall = block[22] + (block[23] << 8); |
| boot->SecPerTrack = block[24] + (block[25] << 8); |
| boot->bpbHeads = block[26] + (block[27] << 8); |
| boot->bpbHiddenSecs = block[28] + (block[29] << 8) + |
| (block[30] << 16) + ((u_int32_t)block[31] << 24); |
| boot->bpbHugeSectors = block[32] + (block[33] << 8) + |
| (block[34] << 16) + ((u_int32_t)block[35] << 24); |
| |
| boot->FATsecs = boot->bpbFATsmall; |
| |
| if (!boot->bpbRootDirEnts) |
| boot->flags |= FAT32; |
| if (boot->flags & FAT32) { |
| boot->FATsecs = block[36] + (block[37] << 8) |
| + (block[38] << 16) + ((u_int32_t)block[39] << 24); |
| if (block[40] & 0x80) |
| boot->ValidFat = block[40] & 0x0f; |
| |
| /* check version number: */ |
| if (block[42] || block[43]) { |
| /* Correct? XXX */ |
| pfatal("Unknown file system version: %x.%x", |
| block[43], block[42]); |
| return FSFATAL; |
| } |
| boot->bpbRootClust = block[44] + (block[45] << 8) |
| + (block[46] << 16) + ((cl_t)block[47] << 24); |
| boot->bpbFSInfo = block[48] + (block[49] << 8); |
| boot->bpbBackup = block[50] + (block[51] << 8); |
| |
| if (lseek(dosfs, boot->bpbFSInfo * boot->bpbBytesPerSec, |
| SEEK_SET) != boot->bpbFSInfo * boot->bpbBytesPerSec |
| || read(dosfs, fsinfo, sizeof fsinfo) != sizeof fsinfo) { |
| perr("could not read fsinfo block"); |
| return FSFATAL; |
| } |
| if (memcmp(fsinfo, "RRaA", 4) |
| || memcmp(fsinfo + 0x1e4, "rrAa", 4) |
| || fsinfo[0x1fc] |
| || fsinfo[0x1fd] |
| || fsinfo[0x1fe] != 0x55 |
| || fsinfo[0x1ff] != 0xaa |
| || fsinfo[0x3fc] |
| || fsinfo[0x3fd] |
| || fsinfo[0x3fe] != 0x55 |
| || fsinfo[0x3ff] != 0xaa) { |
| pwarn("Invalid signature in fsinfo block\n"); |
| if (ask(0, "Fix")) { |
| memcpy(fsinfo, "RRaA", 4); |
| memcpy(fsinfo + 0x1e4, "rrAa", 4); |
| fsinfo[0x1fc] = fsinfo[0x1fd] = 0; |
| fsinfo[0x1fe] = 0x55; |
| fsinfo[0x1ff] = 0xaa; |
| fsinfo[0x3fc] = fsinfo[0x3fd] = 0; |
| fsinfo[0x3fe] = 0x55; |
| fsinfo[0x3ff] = 0xaa; |
| if (lseek(dosfs, boot->bpbFSInfo * |
| boot->bpbBytesPerSec, SEEK_SET) |
| != boot->bpbFSInfo * boot->bpbBytesPerSec |
| || write(dosfs, fsinfo, sizeof fsinfo) |
| != sizeof fsinfo) { |
| perr("Unable to write bpbFSInfo"); |
| return FSFATAL; |
| } |
| ret = FSBOOTMOD; |
| } else |
| boot->bpbFSInfo = 0; |
| } |
| if (boot->bpbFSInfo) { |
| boot->FSFree = fsinfo[0x1e8] + (fsinfo[0x1e9] << 8) |
| + (fsinfo[0x1ea] << 16) |
| + ((cl_t)fsinfo[0x1eb] << 24); |
| boot->FSNext = fsinfo[0x1ec] + (fsinfo[0x1ed] << 8) |
| + (fsinfo[0x1ee] << 16) |
| + ((cl_t)fsinfo[0x1ef] << 24); |
| } |
| |
| if (lseek(dosfs, boot->bpbBackup * boot->bpbBytesPerSec, |
| SEEK_SET) |
| != boot->bpbBackup * boot->bpbBytesPerSec |
| || read(dosfs, backup, sizeof backup) != sizeof backup) { |
| perr("could not read backup bootblock"); |
| return FSFATAL; |
| } |
| backup[65] = block[65]; /* XXX */ |
| if (memcmp(block + 11, backup + 11, 79)) { |
| /* |
| * XXX We require a reference that explains |
| * that these bytes need to match, or should |
| * drop the check. gdt@NetBSD has observed |
| * filesystems that work fine under Windows XP |
| * and NetBSD that do not match, so the |
| * requirement is suspect. For now, just |
| * print out useful information and continue. |
| */ |
| pfatal("backup (block %d) mismatch with primary bootblock:\n", |
| boot->bpbBackup); |
| for (i = 11; i < 11 + 90; i++) { |
| if (block[i] != backup[i]) |
| pfatal("\ti=%d\tprimary 0x%02x\tbackup 0x%02x\n", |
| i, block[i], backup[i]); |
| } |
| } |
| /* Check backup bpbFSInfo? XXX */ |
| } |
| |
| boot->ClusterOffset = (boot->bpbRootDirEnts * 32 + |
| boot->bpbBytesPerSec - 1) / boot->bpbBytesPerSec + |
| boot->bpbResSectors + boot->bpbFATs * boot->FATsecs - |
| CLUST_FIRST * boot->bpbSecPerClust; |
| |
| if (boot->bpbBytesPerSec % DOSBOOTBLOCKSIZE_REAL != 0) { |
| pfatal("Invalid sector size: %u", boot->bpbBytesPerSec); |
| return FSFATAL; |
| } |
| if (boot->bpbSecPerClust == 0) { |
| pfatal("Invalid cluster size: %u", boot->bpbSecPerClust); |
| return FSFATAL; |
| } |
| if (boot->bpbSectors) { |
| boot->bpbHugeSectors = 0; |
| boot->NumSectors = boot->bpbSectors; |
| } else |
| boot->NumSectors = boot->bpbHugeSectors; |
| boot->NumClusters = (boot->NumSectors - boot->ClusterOffset) / |
| boot->bpbSecPerClust; |
| |
| if (boot->flags&FAT32) |
| boot->ClustMask = CLUST32_MASK; |
| else if (boot->NumClusters < (CLUST_RSRVD&CLUST12_MASK)) |
| boot->ClustMask = CLUST12_MASK; |
| else if (boot->NumClusters < (CLUST_RSRVD&CLUST16_MASK)) |
| boot->ClustMask = CLUST16_MASK; |
| else { |
| pfatal("Filesystem too big (%u clusters) for non-FAT32 partition", |
| boot->NumClusters); |
| return FSFATAL; |
| } |
| |
| switch (boot->ClustMask) { |
| case CLUST32_MASK: |
| boot->NumFatEntries = (boot->FATsecs * boot->bpbBytesPerSec) / 4; |
| break; |
| case CLUST16_MASK: |
| boot->NumFatEntries = (boot->FATsecs * boot->bpbBytesPerSec) / 2; |
| break; |
| default: |
| boot->NumFatEntries = (boot->FATsecs * boot->bpbBytesPerSec * 2) / 3; |
| break; |
| } |
| |
| if (boot->NumFatEntries < boot->NumClusters - CLUST_FIRST) { |
| pfatal("FAT size too small, %u entries won't fit into %u sectors\n", |
| boot->NumClusters, boot->FATsecs); |
| return FSFATAL; |
| } |
| boot->ClusterSize = boot->bpbBytesPerSec * boot->bpbSecPerClust; |
| |
| boot->NumFiles = 1; |
| boot->NumFree = 0; |
| |
| // @localmod begin |
| // The BSD FAT driver follows the FAT specification of the "dirty bit" |
| // exactly. The Linux FAT driver, however, marks a bit in the boot sector as |
| // "dirty", which is outside the typical FAT specification. For maximum |
| // compatibility, this modification allows fsck to detect (and clean) the |
| // unspecified Linux dirty bit. |
| int dirtybyte = boot->flags&FAT32 ? 0x41 : 0x25; |
| if (block[dirtybyte] & 0x01) { |
| if (ask(1, "MARK BOOT BLOCK CLEAN") == 0) { |
| pwarn("\n***** BOOT BLOCK IS LEFT MARKED AS DIRTY *****\n"); |
| return FSERROR; |
| } |
| pwarn("MARKING BOOT BLOCK CLEAN\n"); |
| block[dirtybyte] &= ~0x01; |
| if (lseek(dosfs, 0, SEEK_SET) != 0 |
| || write(dosfs, block, sizeof block) != sizeof block) { |
| perr("could not write boot block"); |
| return FSFATAL; |
| } |
| } |
| // @localmod end |
| |
| return ret; |
| } |
| |
| int |
| writefsinfo(int dosfs, struct bootblock *boot) |
| { |
| u_char fsinfo[2 * DOSBOOTBLOCKSIZE]; |
| |
| if (lseek(dosfs, boot->bpbFSInfo * boot->bpbBytesPerSec, SEEK_SET) |
| != boot->bpbFSInfo * boot->bpbBytesPerSec |
| || read(dosfs, fsinfo, sizeof fsinfo) != sizeof fsinfo) { |
| perr("could not read fsinfo block"); |
| return FSFATAL; |
| } |
| fsinfo[0x1e8] = (u_char)boot->FSFree; |
| fsinfo[0x1e9] = (u_char)(boot->FSFree >> 8); |
| fsinfo[0x1ea] = (u_char)(boot->FSFree >> 16); |
| fsinfo[0x1eb] = (u_char)(boot->FSFree >> 24); |
| fsinfo[0x1ec] = (u_char)boot->FSNext; |
| fsinfo[0x1ed] = (u_char)(boot->FSNext >> 8); |
| fsinfo[0x1ee] = (u_char)(boot->FSNext >> 16); |
| fsinfo[0x1ef] = (u_char)(boot->FSNext >> 24); |
| if (lseek(dosfs, boot->bpbFSInfo * boot->bpbBytesPerSec, SEEK_SET) |
| != boot->bpbFSInfo * boot->bpbBytesPerSec |
| || write(dosfs, fsinfo, sizeof fsinfo) |
| != sizeof fsinfo) { |
| perr("Unable to write bpbFSInfo"); |
| return FSFATAL; |
| } |
| /* |
| * Technically, we should return FSBOOTMOD here. |
| * |
| * However, since Win95 OSR2 (the first M$ OS that has |
| * support for FAT32) doesn't maintain the FSINFO block |
| * correctly, it has to be fixed pretty often. |
| * |
| * Therefor, we handle the FSINFO block only informally, |
| * fixing it if necessary, but otherwise ignoring the |
| * fact that it was incorrect. |
| */ |
| return 0; |
| } |