Index: head/sbin/fsck_msdosfs/fat.c =================================================================== --- head/sbin/fsck_msdosfs/fat.c (revision 345893) +++ head/sbin/fsck_msdosfs/fat.c (revision 345894) @@ -1,713 +1,727 @@ /*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (C) 1995, 1996, 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 #ifndef lint __RCSID("$NetBSD: fat.c,v 1.18 2006/06/05 16:51:18 christos Exp $"); static const char rcsid[] = "$FreeBSD$"; #endif /* not lint */ #include #include #include #include #include #include "ext.h" #include "fsutil.h" static int checkclnum(struct bootblock *, u_int, cl_t, cl_t *); static int clustdiffer(cl_t, cl_t *, cl_t *, u_int); static int tryclear(struct bootblock *, struct fatEntry *, cl_t, cl_t *); static int _readfat(int, struct bootblock *, u_int, u_char **); /*- * The first 2 FAT entries contain pseudo-cluster numbers with the following * layout: * * 31...... ........ ........ .......0 * rrrr1111 11111111 11111111 mmmmmmmm FAT32 entry 0 * rrrrsh11 11111111 11111111 11111xxx FAT32 entry 1 * * 11111111 mmmmmmmm FAT16 entry 0 * sh111111 11111xxx FAT16 entry 1 * * r = reserved * m = BPB media ID byte * s = clean flag (1 = dismounted; 0 = still mounted) * h = hard error flag (1 = ok; 0 = I/O error) * x = any value ok */ int checkdirty(int fs, struct bootblock *boot) { off_t off; u_char *buffer; int ret = 0; size_t len; if (boot->ClustMask != CLUST16_MASK && boot->ClustMask != CLUST32_MASK) return 0; off = boot->bpbResSectors; off *= boot->bpbBytesPerSec; buffer = malloc(len = boot->bpbBytesPerSec); if (buffer == NULL) { perr("No space for FAT sectors (%zu)", len); return 1; } if (lseek(fs, off, SEEK_SET) != off) { perr("Unable to read FAT"); goto err; } if ((size_t)read(fs, buffer, boot->bpbBytesPerSec) != boot->bpbBytesPerSec) { perr("Unable to read FAT"); goto err; } /* * If we don't understand the FAT, then the file system must be * assumed to be unclean. */ if (buffer[0] != boot->bpbMedia || buffer[1] != 0xff) goto err; if (boot->ClustMask == CLUST16_MASK) { if ((buffer[2] & 0xf8) != 0xf8 || (buffer[3] & 0x3f) != 0x3f) goto err; } else { if (buffer[2] != 0xff || (buffer[3] & 0x0f) != 0x0f || (buffer[4] & 0xf8) != 0xf8 || buffer[5] != 0xff || buffer[6] != 0xff || (buffer[7] & 0x03) != 0x03) goto err; } /* * Now check the actual clean flag (and the no-error flag). */ if (boot->ClustMask == CLUST16_MASK) { if ((buffer[3] & 0xc0) == 0xc0) ret = 1; } else { if ((buffer[7] & 0x0c) == 0x0c) ret = 1; } err: free(buffer); return ret; } /* * Check a cluster number for valid value */ static int checkclnum(struct bootblock *boot, u_int fat, cl_t cl, cl_t *next) { if (*next >= (CLUST_RSRVD&boot->ClustMask)) *next |= ~boot->ClustMask; if (*next == CLUST_FREE) { boot->NumFree++; return FSOK; } if (*next == CLUST_BAD) { boot->NumBad++; return FSOK; } if (*next < CLUST_FIRST || (*next >= boot->NumClusters && *next < CLUST_EOFS)) { pwarn("Cluster %u in FAT %d continues with %s cluster number %u\n", cl, fat, *next < CLUST_RSRVD ? "out of range" : "reserved", *next&boot->ClustMask); if (ask(0, "Truncate")) { *next = CLUST_EOF; return FSFATMOD; } return FSERROR; } return FSOK; } /* * Read a FAT from disk. Returns 1 if successful, 0 otherwise. */ static int _readfat(int fs, struct bootblock *boot, u_int no, u_char **buffer) { off_t off; size_t len; *buffer = malloc(len = boot->FATsecs * boot->bpbBytesPerSec); if (*buffer == NULL) { perr("No space for FAT sectors (%zu)", len); return 0; } off = boot->bpbResSectors + no * boot->FATsecs; off *= boot->bpbBytesPerSec; if (lseek(fs, off, SEEK_SET) != off) { perr("Unable to read FAT"); goto err; } if ((size_t)read(fs, *buffer, boot->FATsecs * boot->bpbBytesPerSec) != boot->FATsecs * boot->bpbBytesPerSec) { perr("Unable to read FAT"); goto err; } return 1; err: free(*buffer); return 0; } /* * Read a FAT and decode it into internal format */ int readfat(int fs, struct bootblock *boot, u_int no, struct fatEntry **fp) { struct fatEntry *fat; u_char *buffer, *p; cl_t cl; int ret = FSOK; size_t len; boot->NumFree = boot->NumBad = 0; if (!_readfat(fs, boot, no, &buffer)) return FSFATAL; fat = malloc(len = boot->NumClusters * sizeof(struct fatEntry)); if (fat == NULL) { perr("No space for FAT clusters (%zu)", len); free(buffer); return FSFATAL; } (void)memset(fat, 0, len); if (buffer[0] != boot->bpbMedia || buffer[1] != 0xff || buffer[2] != 0xff || (boot->ClustMask == CLUST16_MASK && buffer[3] != 0xff) || (boot->ClustMask == CLUST32_MASK && ((buffer[3]&0x0f) != 0x0f || buffer[4] != 0xff || buffer[5] != 0xff || buffer[6] != 0xff || (buffer[7]&0x0f) != 0x0f))) { /* Windows 95 OSR2 (and possibly any later) changes * the FAT signature to 0xXXffff7f for FAT16 and to * 0xXXffff0fffffff07 for FAT32 upon boot, to know that the * file system is dirty if it doesn't reboot cleanly. * Check this special condition before errorring out. */ if (buffer[0] == boot->bpbMedia && buffer[1] == 0xff && buffer[2] == 0xff && ((boot->ClustMask == CLUST16_MASK && buffer[3] == 0x7f) || (boot->ClustMask == CLUST32_MASK && buffer[3] == 0x0f && buffer[4] == 0xff && buffer[5] == 0xff && buffer[6] == 0xff && buffer[7] == 0x07))) ret |= FSDIRTY; else { /* just some odd byte sequence in FAT */ switch (boot->ClustMask) { case CLUST32_MASK: pwarn("%s (%02x%02x%02x%02x%02x%02x%02x%02x)\n", "FAT starts with odd byte sequence", buffer[0], buffer[1], buffer[2], buffer[3], buffer[4], buffer[5], buffer[6], buffer[7]); break; case CLUST16_MASK: pwarn("%s (%02x%02x%02x%02x)\n", "FAT starts with odd byte sequence", buffer[0], buffer[1], buffer[2], buffer[3]); break; default: pwarn("%s (%02x%02x%02x)\n", "FAT starts with odd byte sequence", buffer[0], buffer[1], buffer[2]); break; } if (ask(1, "Correct")) ret |= FSFIXFAT; } } switch (boot->ClustMask) { case CLUST32_MASK: p = buffer + 8; break; case CLUST16_MASK: p = buffer + 4; break; default: p = buffer + 3; break; } for (cl = CLUST_FIRST; cl < boot->NumClusters;) { switch (boot->ClustMask) { case CLUST32_MASK: fat[cl].next = p[0] + (p[1] << 8) + (p[2] << 16) + (p[3] << 24); fat[cl].next &= boot->ClustMask; ret |= checkclnum(boot, no, cl, &fat[cl].next); cl++; p += 4; break; case CLUST16_MASK: fat[cl].next = p[0] + (p[1] << 8); ret |= checkclnum(boot, no, cl, &fat[cl].next); cl++; p += 2; break; default: fat[cl].next = (p[0] + (p[1] << 8)) & 0x0fff; ret |= checkclnum(boot, no, cl, &fat[cl].next); cl++; if (cl >= boot->NumClusters) break; fat[cl].next = ((p[1] >> 4) + (p[2] << 4)) & 0x0fff; ret |= checkclnum(boot, no, cl, &fat[cl].next); cl++; p += 3; break; } } free(buffer); if (ret & FSFATAL) { free(fat); *fp = NULL; } else *fp = fat; return ret; } /* * Get type of reserved cluster */ const char * rsrvdcltype(cl_t cl) { if (cl == CLUST_FREE) return "free"; if (cl < CLUST_BAD) return "reserved"; if (cl > CLUST_BAD) return "as EOF"; return "bad"; } static int clustdiffer(cl_t cl, cl_t *cp1, cl_t *cp2, u_int fatnum) { if (*cp1 == CLUST_FREE || *cp1 >= CLUST_RSRVD) { if (*cp2 == CLUST_FREE || *cp2 >= CLUST_RSRVD) { if ((*cp1 != CLUST_FREE && *cp1 < CLUST_BAD && *cp2 != CLUST_FREE && *cp2 < CLUST_BAD) || (*cp1 > CLUST_BAD && *cp2 > CLUST_BAD)) { pwarn("Cluster %u is marked %s with different indicators\n", cl, rsrvdcltype(*cp1)); if (ask(1, "Fix")) { *cp2 = *cp1; return FSFATMOD; } return FSFATAL; } pwarn("Cluster %u is marked %s in FAT 0, %s in FAT %u\n", cl, rsrvdcltype(*cp1), rsrvdcltype(*cp2), fatnum); if (ask(0, "Use FAT 0's entry")) { *cp2 = *cp1; return FSFATMOD; } if (ask(0, "Use FAT %u's entry", fatnum)) { *cp1 = *cp2; return FSFATMOD; } return FSFATAL; } pwarn("Cluster %u is marked %s in FAT 0, but continues with cluster %u in FAT %d\n", cl, rsrvdcltype(*cp1), *cp2, fatnum); if (ask(0, "Use continuation from FAT %u", fatnum)) { *cp1 = *cp2; return FSFATMOD; } if (ask(0, "Use mark from FAT 0")) { *cp2 = *cp1; return FSFATMOD; } return FSFATAL; } if (*cp2 == CLUST_FREE || *cp2 >= CLUST_RSRVD) { pwarn("Cluster %u continues with cluster %u in FAT 0, but is marked %s in FAT %u\n", cl, *cp1, rsrvdcltype(*cp2), fatnum); if (ask(0, "Use continuation from FAT 0")) { *cp2 = *cp1; return FSFATMOD; } if (ask(0, "Use mark from FAT %d", fatnum)) { *cp1 = *cp2; return FSFATMOD; } return FSERROR; } pwarn("Cluster %u continues with cluster %u in FAT 0, but with cluster %u in FAT %u\n", cl, *cp1, *cp2, fatnum); if (ask(0, "Use continuation from FAT 0")) { *cp2 = *cp1; return FSFATMOD; } if (ask(0, "Use continuation from FAT %u", fatnum)) { *cp1 = *cp2; return FSFATMOD; } return FSERROR; } /* * Compare two FAT copies in memory. Resolve any conflicts and merge them * into the first one. */ int comparefat(struct bootblock *boot, struct fatEntry *first, struct fatEntry *second, u_int fatnum) { cl_t cl; int ret = FSOK; for (cl = CLUST_FIRST; cl < boot->NumClusters; cl++) if (first[cl].next != second[cl].next) ret |= clustdiffer(cl, &first[cl].next, &second[cl].next, fatnum); return ret; } void clearchain(struct bootblock *boot, struct fatEntry *fat, cl_t head) { cl_t p, q; for (p = head; p >= CLUST_FIRST && p < boot->NumClusters; p = q) { if (fat[p].head != head) break; q = fat[p].next; fat[p].next = fat[p].head = CLUST_FREE; fat[p].length = 0; } } int tryclear(struct bootblock *boot, struct fatEntry *fat, cl_t head, cl_t *truncp) { if (ask(0, "Clear chain starting at %u", head)) { clearchain(boot, fat, head); return FSFATMOD; } else if (ask(0, "Truncate")) { uint32_t len; cl_t p; for (p = head, len = 0; p >= CLUST_FIRST && p < boot->NumClusters; p = fat[p].next, len++) continue; *truncp = CLUST_EOF; fat[head].length = len; return FSFATMOD; } else return FSERROR; } /* * Check a complete FAT in-memory for crosslinks */ int checkfat(struct bootblock *boot, struct fatEntry *fat) { cl_t head, p, h, n; u_int len; int ret = 0; int conf; /* * pass 1: figure out the cluster chains. */ for (head = CLUST_FIRST; head < boot->NumClusters; head++) { /* find next untravelled chain */ if (fat[head].head != 0 /* cluster already belongs to some chain */ || fat[head].next == CLUST_FREE || fat[head].next == CLUST_BAD) continue; /* skip it. */ /* follow the chain and mark all clusters on the way */ for (len = 0, p = head; p >= CLUST_FIRST && p < boot->NumClusters && fat[p].head != head; p = fat[p].next) { fat[p].head = head; len++; } /* the head record gets the length */ fat[head].length = fat[head].next == CLUST_FREE ? 0 : len; } /* * pass 2: check for crosslinked chains (we couldn't do this in pass 1 because * we didn't know the real start of the chain then - would have treated partial * chains as interlinked with their main chain) */ for (head = CLUST_FIRST; head < boot->NumClusters; head++) { /* find next untravelled chain */ if (fat[head].head != head) continue; /* follow the chain to its end (hopefully) */ for (len = fat[head].length, p = head; (n = fat[p].next) >= CLUST_FIRST && n < boot->NumClusters; p = n) if (fat[n].head != head || len-- < 2) break; if (n >= CLUST_EOFS) continue; if (n == CLUST_FREE || n >= CLUST_RSRVD) { pwarn("Cluster chain starting at %u ends with cluster marked %s\n", head, rsrvdcltype(n)); clear: ret |= tryclear(boot, fat, head, &fat[p].next); continue; } if (n < CLUST_FIRST || n >= boot->NumClusters) { pwarn("Cluster chain starting at %u ends with cluster out of range (%u)\n", head, n); goto clear; } if (head == fat[n].head) { pwarn("Cluster chain starting at %u loops at cluster %u\n", head, p); goto clear; } pwarn("Cluster chains starting at %u and %u are linked at cluster %u\n", head, fat[n].head, n); conf = tryclear(boot, fat, head, &fat[p].next); if (ask(0, "Clear chain starting at %u", h = fat[n].head)) { if (conf == FSERROR) { /* * Transfer the common chain to the one not cleared above. */ for (p = n; p >= CLUST_FIRST && p < boot->NumClusters; p = fat[p].next) { if (h != fat[p].head) { /* * Have to reexamine this chain. */ head--; break; } fat[p].head = head; } } clearchain(boot, fat, h); conf |= FSFATMOD; } ret |= conf; } return ret; } /* * Write out FATs encoding them from the internal format */ int writefat(int fs, struct bootblock *boot, struct fatEntry *fat, int correct_fat) { u_char *buffer, *p; cl_t cl; u_int i; size_t fatsz; off_t off; int ret = FSOK; buffer = malloc(fatsz = boot->FATsecs * boot->bpbBytesPerSec); if (buffer == NULL) { perr("No space for FAT sectors (%zu)", fatsz); return FSFATAL; } memset(buffer, 0, fatsz); boot->NumFree = 0; p = buffer; if (correct_fat) { *p++ = (u_char)boot->bpbMedia; *p++ = 0xff; *p++ = 0xff; switch (boot->ClustMask) { case CLUST16_MASK: *p++ = 0xff; break; case CLUST32_MASK: *p++ = 0x0f; *p++ = 0xff; *p++ = 0xff; *p++ = 0xff; *p++ = 0x0f; break; } } else { /* use same FAT signature as the old FAT has */ int count; u_char *old_fat; switch (boot->ClustMask) { case CLUST32_MASK: count = 8; break; case CLUST16_MASK: count = 4; break; default: count = 3; break; } if (!_readfat(fs, boot, boot->ValidFat >= 0 ? boot->ValidFat :0, &old_fat)) { free(buffer); return FSFATAL; } memcpy(p, old_fat, count); free(old_fat); p += count; } for (cl = CLUST_FIRST; cl < boot->NumClusters; cl++) { switch (boot->ClustMask) { case CLUST32_MASK: if (fat[cl].next == CLUST_FREE) boot->NumFree++; *p++ = (u_char)fat[cl].next; *p++ = (u_char)(fat[cl].next >> 8); *p++ = (u_char)(fat[cl].next >> 16); *p &= 0xf0; *p++ |= (fat[cl].next >> 24)&0x0f; break; case CLUST16_MASK: if (fat[cl].next == CLUST_FREE) boot->NumFree++; *p++ = (u_char)fat[cl].next; *p++ = (u_char)(fat[cl].next >> 8); break; default: if (fat[cl].next == CLUST_FREE) boot->NumFree++; *p++ = (u_char)fat[cl].next; *p = (u_char)((fat[cl].next >> 8) & 0xf); cl++; if (cl >= boot->NumClusters) break; if (fat[cl].next == CLUST_FREE) boot->NumFree++; *p++ |= (u_char)(fat[cl + 1].next << 4); *p++ = (u_char)(fat[cl + 1].next >> 4); break; } } for (i = 0; i < boot->bpbFATs; i++) { off = boot->bpbResSectors + i * boot->FATsecs; off *= boot->bpbBytesPerSec; if (lseek(fs, off, SEEK_SET) != off || (size_t)write(fs, buffer, fatsz) != fatsz) { perr("Unable to write FAT"); ret = FSFATAL; /* Return immediately? XXX */ } } free(buffer); return ret; } /* * Check a complete in-memory FAT for lost cluster chains */ int checklost(int dosfs, struct bootblock *boot, struct fatEntry *fat) { cl_t head; int mod = FSOK; int ret; for (head = CLUST_FIRST; head < boot->NumClusters; head++) { /* find next untravelled chain */ if (fat[head].head != head || fat[head].next == CLUST_FREE || (fat[head].next >= CLUST_RSRVD && fat[head].next < CLUST_EOFS) || (fat[head].flags & FAT_USED)) continue; pwarn("Lost cluster chain at cluster %u\n%d Cluster(s) lost\n", head, fat[head].length); mod |= ret = reconnect(dosfs, boot, fat, head); if (mod & FSFATAL) break; if (ret == FSERROR && ask(0, "Clear")) { clearchain(boot, fat, head); mod |= FSFATMOD; } } finishlf(); if (boot->bpbFSInfo) { ret = 0; if (boot->FSFree != 0xffffffffU && boot->FSFree != boot->NumFree) { pwarn("Free space in FSInfo block (%u) not correct (%u)\n", boot->FSFree, boot->NumFree); if (ask(1, "Fix")) { boot->FSFree = boot->NumFree; ret = 1; } } + if (boot->FSNext != 0xffffffffU && + (boot->FSNext >= boot->NumClusters || + (boot->NumFree && fat[boot->FSNext].next != CLUST_FREE))) { + pwarn("Next free cluster in FSInfo block (%u) %s\n", + boot->FSNext, + (boot->FSNext >= boot->NumClusters) ? "invalid" : "not free"); + if (ask(1, "fix")) + for (head = CLUST_FIRST; head < boot->NumClusters; head++) + if (fat[head].next == CLUST_FREE) { + boot->FSNext = head; + ret = 1; + break; + } + } if (ret) mod |= writefsinfo(dosfs, boot); } return mod; }