/* * 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Martin Husemann * and Wolfgang Solfrank. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * 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 #include #include #include #include #ifndef lint __RCSID("$NetBSD: fat.c,v 1.12 2000/10/10 20:24:52 is Exp $"); static const char rcsid[] = "$FreeBSD: src/sbin/fsck_msdosfs/fat.c,v 1.9 2008/01/31 13:22:13 yar Exp $"; #endif /* not lint */ #include #include #include #include #include #include "ext.h" #include "fsutil.h" #include "fatcache.h" #include "fragment.h" static int checkclnum(struct bootblock *, cl_t, cl_t *); static int clustdiffer(cl_t, cl_t *, cl_t *, int,int *); static int tryclear(struct bootblock* ,struct cluster_chain_descriptor *, cl_t, cl_t *); int _readfat(int, struct bootblock *, int, u_char **); static cl_t firstfreecl = 0xFFFFFFFF; /*- * 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; if (boot->ClustMask != CLUST16_MASK && boot->ClustMask != CLUST32_MASK) return 0; off = boot->ResSectors; off *= boot->BytesPerSec; buffer = malloc(boot->BytesPerSec); if (buffer == NULL) { perror("No space for FAT"); return 1; } if (lseek(fs, off, SEEK_SET) != off) { perror("Unable to read FAT"); goto err; } if (read(fs, buffer, boot->BytesPerSec) != boot->BytesPerSec) { perror("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->Media || 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 struct fragment *lastfree= NULL; static struct fragment *lastbad= NULL; int checkclnum(struct bootblock *boot, cl_t cl, cl_t *next) { struct fragment *frag; struct fragment *insert; if((*next >= (CLUST_EOFS & boot->ClustMask)) && (*next <= (CLUST_EOF & boot->ClustMask))) return FSOK; if(*next >= (CLUST_RSRVD & boot->ClustMask)){ *next |= ~boot->ClustMask; } /*if it is a free cluster,add to rb_free_root tree*/ if (*next == CLUST_FREE) { boot->NumFree++; /*find the first free cluster ,this value will be used to update fsinfo*/ if(firstfreecl > cl) firstfreecl = cl; if(lastfree){ if( cl == (lastfree->head + lastfree->length)){ lastfree->length += 1; return FSOK; } } frag = New_fragment(); if(!frag){ fsck_info("No space \n"); return FSERROR; } frag->head = cl; frag->length = 1; insert = RB_INSERT(FSCK_MSDOS_FRAGMENT,&rb_free_root,frag); if(insert){ fsck_info("%s:fragment(head:0x%x) exist\n",__func__,frag->head); return FSERROR; } lastfree = frag; return FSOK; } /*if it is a bad cluster ,add to rb_bad_root tree*/ if (*next == CLUST_BAD) { boot->NumBad++; if(lastbad){ if(cl == (lastbad->head + lastbad->length)){ lastbad->length += 1; return FSOK; } } frag = New_fragment(); if(!frag){ fsck_info("No Space\n"); return FSERROR; } frag->head = cl; frag->length = 1; insert = RB_INSERT(FSCK_MSDOS_FRAGMENT,&rb_bad_root,frag); if(insert){ fsck_info("%s:fragment(head:0x%x) exist\n",__func__,frag->head); return FSERROR; } lastbad = frag; return FSOK; } if (*next < CLUST_FIRST || (*next >= boot->NumClusters && *next < (CLUST_EOFS & boot->ClustMask))) { pwarn("Cluster %u in FAT continues with %s cluster number %u\n", cl, *next < CLUST_RSRVD ? "out of range" : "reserved", *next&boot->ClustMask); if (ask(1, "Truncate")) { /*do nothing about truncate*/ return FSFATMOD; } return FSERROR; } return FSOK; } /* * Read a FAT from disk. Returns 1 if successful, 0 otherwise. */ int _readfat(int fs, struct bootblock *boot, int no, u_char **buffer) { off_t off; printf("Attempting to allocate %u KB for FAT\n", (boot->FATsecs * boot->BytesPerSec) / 1024); *buffer = malloc(boot->FATsecs * boot->BytesPerSec); if (*buffer == NULL) { perror("No space for FAT"); return 0; } off = boot->ResSectors + no * boot->FATsecs; off *= boot->BytesPerSec; if (lseek(fs, off, SEEK_SET) != off) { perror("Unable to read FAT"); goto err; } if (read(fs, *buffer, boot->FATsecs * boot->BytesPerSec) != boot->FATsecs * boot->BytesPerSec) { perror("Unable to read FAT"); goto err; } return 1; err: free(*buffer); return 0; } /* * Read a FAT and decode it into internal format */ unsigned int *fat_bitmap; int checkfat(int fs, struct bootblock *boot, int no,u_char *buffer) { struct cluster_chain_descriptor *fat = NULL,*nextcl_fat,*insert,*remove,tofind; struct fatcache *cache = NULL; u_char *p; cl_t cl,prevcl = 0, nextclus; int len = 0; int ret = FSOK,err = 0; boot->NumFree = boot->NumBad = 0; fat_bitmap = calloc(boot->NumClusters/32+1,sizeof(unsigned int)); if(!fat_bitmap){ fsck_err("NO space left\n"); return FSFATAL; } if (buffer[0] != boot->Media || 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->Media && 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; } } fsck_info("Begin to handle the cluster chain\n"); for (cl = CLUST_FIRST; cl < boot->NumClusters;cl++) { /*have handled it by cluster chain*/ if(BIT(fat_bitmap[cl/32],cl%32)) continue; prevcl = nextclus = cl; len = 0; switch (boot->ClustMask) { case CLUST32_MASK: p = buffer + 4*cl; break; case CLUST16_MASK: p = buffer + 2*cl; break; default: p = buffer + 3*(cl/2); break; } while(nextclus >= CLUST_FIRST && nextclus < boot->NumClusters){ switch (boot->ClustMask) { case CLUST32_MASK: nextclus = p[0] + (p[1] << 8) + (p[2] << 16) + (p[3] << 24); nextclus &= boot->ClustMask; p = buffer + 4*nextclus; break; case CLUST16_MASK: nextclus = p[0] + (p[1] << 8); p = buffer + 2*nextclus; break; /*FAT12 is special*/ default: /* odd */ if(!(nextclus & 0x1)) nextclus = (p[0] + (p[1] << 8)) & 0x0fff; else nextclus = ((p[1] >> 4) + (p[2] << 4)) & 0x0fff; p = buffer + 3*(nextclus/2); break; } err = checkclnum(boot,prevcl,&nextclus); ret |= err; if(err & FSERROR) return -1; //truncate the rest clusters if(err & FSFATMOD) break; len++; /* *TODO:because this cluster chain is special,such as *fatentry->fatcache->fatcache->fatcache->NULL *so you should treat the first fatcache specially */ if(len == 1){ if(nextclus == CLUST_FREE || nextclus == CLUST_BAD ){ SET_BIT(fat_bitmap[prevcl/32],prevcl%32); break; } } /*last cluster*/ if((nextclus >= (CLUST_EOFS & boot->ClustMask)) && (nextclus <= (CLUST_EOF & boot->ClustMask)) && (len != 1)){ SET_BIT(fat_bitmap[prevcl/32],prevcl%32); break; } /*rsrvd*/ if(nextclus == CLUST_FREE || ((nextclus >= (CLUST_RSRVD & boot->ClustMask)) && (nextclus < (CLUST_EOFS & boot->ClustMask)))){ fsck_warn("Cluster chain starting at %u ends with cluster marked %s,cl = %d ,nextclus = %d\n",cl,rsrvdcltype(nextclus),cl,nextclus); SET_BIT(fat_bitmap[prevcl/32],prevcl%32); /*if the next cluster is free or reversed ,just clear the existing cluster chain ,let this free or reversed cluster alone*/ ret |= tryclear(boot,fat,cl,&prevcl); break; } /*out of range*/ if(nextclus < CLUST_FIRST ||(( nextclus >= boot->NumClusters) && (nextclus < (CLUST_EOFS & boot->ClustMask)))){ fsck_warn("Clusters chain starting at %u ends with cluster out of range (%u) \n",cl,nextclus); SET_BIT(fat_bitmap[prevcl/32],prevcl%32); ret |= tryclear(boot,fat,cl,&prevcl); break; } if((nextclus >= CLUST_FIRST && nextclus < boot->NumClusters)&& BIT(fat_bitmap[nextclus/32],nextclus%32)){ /* *it is interesting,because 0x3->0x34->0x35->EOF,then you find 0x100->0x3. *it is right here,must merge them */ tofind.head = nextclus; nextcl_fat = RB_FIND(FSCK_MSDOS_CACHE,&rb_root,&tofind); /*if nextcl_fat == fat ,unfortunately ,it is a cluster loop,such as 0x2->0x3->0x4->0x2*/ if(nextcl_fat && (nextcl_fat != fat)){ if(len == 1){ /*the first one ,you should malloc both fatEntry and fatcache*/ fat = New_fatentry(); if(!fat) return FSFATAL; fat->head = prevcl; fat->length = 1; /* *i was puzzled whether check the pointer insert here *if some error,there is a exsting fatentry in rb tree.NOT check maybe a good choice */ insert = RB_INSERT(FSCK_MSDOS_CACHE,&rb_root,fat); if(insert){ fsck_err("%s:fatentry(head:0x%x) exist\n",__func__,fat->head); return FSFATAL; } cache = New_fatcache(); if(!cache) return FSFATAL; cache->head = prevcl; cache->length = 1; err = add_fatcache_To_ClusterChain(fat,cache); if(err){ fsck_err("add_fatcache_To_ClusterChain ,err = %d \n",err); return FSFATAL; } /*merge nextcl_fat chain to new one*/ cache->next = nextcl_fat->child; fat->length += nextcl_fat->length; }else{ /* *we use fat directly here,after handling a cluster chain ,must set fat = NULL, *otherwise ,the fat is prev cluster chain */ add_fatcache_Totail(fat,nextcl_fat->child); fat->length += nextcl_fat->length; } nextcl_fat->child = NULL; /*now delete nextcl_fat entry ,because have merge its child to fat*/ remove = RB_REMOVE(FSCK_MSDOS_CACHE,&rb_root,nextcl_fat); free(nextcl_fat); SET_BIT(fat_bitmap[prevcl/32],prevcl%32); break; } /* *it is very complex here,if a cluster has been handled ,but it is not a head of a cluster chain,there are some cases: *case 1:Due to some error ,this cluster has been removed from rb tree by tryclear() *case 2:clsuter chains linked *case 3:cluster loop *whatever ,i think tryclear() is a simplest solution */ fsck_err("Cluster chian is wrong\n"); Dump_fatentry(fat); Dump_fatentry(nextcl_fat); /*sometimes ,fat == NULL here,it means this cluster chain haven't be insert to rb tree,ok,do nothing here*/ if(!fat) break; if(ask(1,"Clear chain starting at %u",nextclus)){ /* *compare with orginal code,i delete some codes here *because i handle fat chain by chain here, *it never appear situation that three or more cluster chains linked */ ret |= tryclear(boot,fat,cl,&prevcl); break; } } /*it is a legal cluster ,add it*/ SET_BIT(fat_bitmap[prevcl/32],prevcl%32); if(len == 1){ /*TODO: *that is the first cluster of this legal chain *it is special ,normally, we just add nextcluster to chain *but if it is first one ,we must add both two. */ fat = New_fatentry(); if(!fat){ fsck_err("No space \n"); return FSFATAL; } fat->head = cl; insert = RB_INSERT(FSCK_MSDOS_CACHE,&rb_root,fat); if(insert){ fsck_err("%s:fatentry(head:0x%x) exist\n",__func__,fat->head); return FSFATAL; } cache = New_fatcache(); if(!cache){ fsck_err("No space \n"); return FSFATAL; } cache->head = prevcl; cache->length = 1; err = add_fatcache_To_ClusterChain(fat,cache); if(err){ fsck_err("add_fatcache_To_ClusterChain ,err = %d \n",err); } if(nextclus >= (CLUST_EOFS & boot->ClustMask) && nextclus <= (CLUST_EOF & boot->ClustMask)){ break; } if(prevcl + 1 == nextclus){ cache->length += 1; fat->length += 1; prevcl = nextclus; continue; }else{ cache = New_fatcache(); if(!cache){ fsck_err("No space\n"); return FSFATAL; } cache->head = nextclus; cache->length = 1; err = add_fatcache_To_ClusterChain(fat,cache); if(err){ fsck_err("add_fatcache_To_ClusterChain ,err = %d \n",err); } } }else{ if(nextclus >= (CLUST_EOFS & boot->ClustMask) && nextclus <= (CLUST_EOF & boot->ClustMask)){ break; } if( prevcl + 1 == nextclus){ /*if it is continuous ,just modify the length*/ cache->length += 1; fat->length += 1; }else{ cache = New_fatcache(); if(!cache){ fsck_err("No Space\n"); return FSFATAL; } cache->head = nextclus; cache->length = 1; err = add_fatcache_To_ClusterChain(fat,cache); if(err){ fsck_err("add_fatcache_To_ClusterChain ,err = %d \n",err); } } } prevcl = nextclus; } /*set fat = NULL,otherwise this fat pointer will impact the next process*/ fat = NULL; } #if 0 fsck_info("Dump cluster chains\n"); RB_FOREACH(fat, FSCK_MSDOS_CACHE,&rb_root){ fsck_info("head:0x%x:length:0x%x\n",fat->head,fat->length); } #endif free(fat_bitmap); return ret; } /* * Get type of reserved cluster */ 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"; } /* *if *res = 1,that means *cp1 = *cp2 *if *res = 0 ,means *cp2 = *cp1; */ static int clustdiffer(cl_t cl, cl_t *cp1, cl_t *cp2, int fatnum, int *res) { fsck_debug("clustdiff:%u : %u \n",*cp1,*cp2); 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")) { *res = 0; return FSFATMOD; } return FSFATAL; } pwarn("Cluster %u is marked %s in FAT 0, %s in FAT %d\n", cl, rsrvdcltype(*cp1), rsrvdcltype(*cp2), fatnum); if (ask(1, "Use FAT 0's entry")) { *res = 0; return FSFATMOD; } if (ask(1, "Use FAT %d's entry", fatnum)) { *res = 1; 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(1, "Use continuation from FAT %d", fatnum)) { *res = 1; return FSFATMOD; } if (ask(1, "Use mark from FAT 0")) { *res = 0; 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 %d\n", cl, *cp1, rsrvdcltype(*cp2), fatnum); if (ask(1, "Use continuation from FAT 0")) { *res = 0; return FSFATMOD; } if (ask(1, "Use mark from FAT %d", fatnum)) { *res = 1; return FSFATMOD; } return FSERROR; } pwarn("Cluster %u continues with cluster %u in FAT 0, but with cluster %u in FAT %d\n", cl, *cp1, *cp2, fatnum); if (ask(1, "Use continuation from FAT 0")) { *res = 0; return FSFATMOD; } if (ask(1, "Use continuation from FAT %d", fatnum)) { *res = 1; 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, u_char*first, u_char *second, int fatnum) { cl_t cl; u_char *sp,*fp,*wp; int ret = FSOK,res = 0; cl_t first_cl,second_cl,w_cl; fsck_info("Begin to compare FAT\n"); for (cl = CLUST_FIRST; cl < boot->NumClusters; cl++){ switch(boot->ClustMask){ case CLUST32_MASK: fp = first + 4*cl; sp = second + 4*cl; first_cl = (fp[0] + (fp[1]<<8) + (fp[2]<<16) + (fp[3]<<24)) & boot->ClustMask; second_cl = (sp[0] + (sp[1]<<8) + (sp[2]<<16) + (sp[3]<<24)) & boot->ClustMask; break; case CLUST16_MASK: fp = first + 2*cl; sp = second + 2*cl; first_cl = (fp[0] + (fp[1] << 8)) & boot->ClustMask; second_cl = (sp[0] + (sp[1] << 8)) & boot->ClustMask; break; default: fp = first + 3*(cl/2); sp = second + 3*(cl/2); if(cl & 0x1){ first_cl = ((fp[1]>>4) + (fp[2]<<4)) & 0x0fff; second_cl = ((sp[1]>>4) + (sp[2]<<4)) & 0x0fff; }else{ first_cl = (fp[0] + (fp[1] << 8)) & 0x0fff; second_cl = (sp[0] + (sp[1] << 8)) & 0x0fff; } break; } if(first_cl == second_cl) continue; fsck_warn("%u is not same(%u ; %u)\n",cl,first_cl,second_cl); ret |= clustdiffer(cl, &first_cl,&second_cl, fatnum,&res); if(res){ wp = fp; w_cl = second_cl; }else{ wp = sp; w_cl = first_cl; } /* fisrt_cl = second_cl */ switch(boot->ClustMask){ case CLUST32_MASK: *wp++ = (u_char)w_cl; *wp++ = (u_char)(w_cl >>8); *wp++ = (u_char)(w_cl >> 16); *wp &= 0xf0; *wp |= (w_cl >>24) &0x0f; break; case CLUST16_MASK: *wp++ = (u_char)w_cl; *wp = (u_char)(w_cl >> 8); break; default: if(cl & 0x1){ /* wp[1] ,wp[2]*/ wp++; *wp++ |= (u_char)((w_cl << 4) & 0xf0); *wp = (u_char)(w_cl >> 4); }else{ /* wp[0] ,wp[1]*/ *wp++ = (u_char)w_cl; *wp |= (u_char)((w_cl >> 8) & 0x0f); } break; } } return ret; } void clearchain(struct bootblock *boot,struct cluster_chain_descriptor *fat, cl_t head) { struct fatcache * curr,*next; struct fragment *frag, *insert; fsck_debug("%s:fat:%p , head(%d) ,length(%d)\n",__func__,fat,fat->head,fat->length); assert(fat); if(fat->head != head) return; /*re-calc free blocks*/ boot->NumFree += fat->length; /*move to free tree for writefat()*/ curr = fat->child; while(curr){ next = curr->next; frag = New_fragment(); if(!frag){ fsck_warn("%s: No space left\n",__func__); goto free; } frag->head = curr->head; frag->length = curr->length; insert = RB_INSERT(FSCK_MSDOS_FRAGMENT,&rb_free_root,frag); if(insert) fsck_warn("%s:fragment(head:0x%x) exist\n",__func__,frag->head); free: free(curr); curr = next; } /*must remove from rb tree before free*/ RB_REMOVE(FSCK_MSDOS_CACHE,&rb_root,fat); free(fat); } int tryclear(struct bootblock* boot, struct cluster_chain_descriptor *fat, cl_t head, cl_t *trunc) { fsck_debug("fat:%p ,head :%d ,trunc :%d \n",fat,head,*trunc); if(!fat || !trunc){ pwarn("%s :null pointer\n",__func__); return FSERROR; } if (ask(1, "Clear chain starting at %u", head)) { clearchain(boot,fat, head); return FSFATMOD; } else if (ask(1, "Truncate")) { Trunc(boot,fat,*trunc); return FSFATMOD; } else return FSERROR; } /* * Write out FATs encoding them from the internal format */ int writefat(int fs, struct bootblock *boot, int correct_fat) { u_char *buffer, *p; cl_t cl; unsigned int i; u_int32_t fatsz; off_t off; int ret = FSOK; struct cluster_chain_descriptor *fat; struct fatcache* cache,*next_cache; struct fragment *frag; fsck_debug("begin to writefat \n"); buffer = malloc(fatsz = boot->FATsecs * boot->BytesPerSec); if (buffer == NULL) { perror("No space for FAT"); return FSFATAL; } memset(buffer, 0, fatsz); p = buffer; if (correct_fat) { *p++ = (u_char)boot->Media; *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; } fsck_info("begin to write FAT\n"); fat = RB_MIN(FSCK_MSDOS_CACHE,&rb_root); if(!fat){ fsck_info("%s:rb tree is empty\n",__func__); return FSFATAL; } fsck_info("write valid cluster chain\n"); while(fat){ cache = fat->child; while(cache){ cl = cache->head; for( i = 0 ; i < (cache->length - 1);i++) SetNextClusToFAT(boot,buffer,cl+i ,cl+i+1); next_cache = cache->next; if(next_cache) SetNextClusToFAT(boot,buffer,cl+cache->length -1,next_cache->head); else SetNextClusToFAT(boot,buffer,cl+cache->length -1,CLUST_EOF); cache = next_cache; } fat = RB_NEXT(FSCK_MSDOS_CACHE,0,fat); } /*the FreeNumber may be not correct*/ fsck_info("write free cluster\n"); RB_FOREACH(frag, FSCK_MSDOS_FRAGMENT,&rb_free_root){ cl = frag->head; for(i = 0 ; i < frag->length ;i++) SetNextClusToFAT(boot,buffer,cl+i ,CLUST_FREE); } fsck_info("write bad cluster\n"); RB_FOREACH(frag, FSCK_MSDOS_FRAGMENT,&rb_bad_root){ cl = frag->head; for(i = 0 ; i < frag->length ;i++) SetNextClusToFAT(boot,buffer,cl+i ,CLUST_BAD); } fsck_debug("write FATs\n"); for (i = 0; i < boot->FATs; i++) { fsck_debug("write FAT copy %d \n",i); off = boot->ResSectors + i * boot->FATsecs; off *= boot->BytesPerSec; if (lseek(fs, off, SEEK_SET) != off || write(fs, buffer, fatsz) != fatsz) { perror("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) { int mod = FSOK; int ret; struct cluster_chain_descriptor *fat, *next; fat = RB_MIN(FSCK_MSDOS_CACHE,&rb_root); if(!fat){ fsck_info("%s:rb_root tree is empty\n",__func__); //After format FAT16,nothing left if(boot->ClustMask & CLUST16_MASK) return FSOK; else return FSFATAL; } while(fat){ if(fat->flag & FAT_USED){ fat = RB_NEXT(FSCK_MSDOS_CACHE,0,fat); continue; } fsck_info("Lost cluster chain at head %u ,%d Cluster(s) lost\n",fat->head, fat->length); mod |= ret = reconnect(dosfs, boot,fat, fat->head); if (mod & FSFATAL) { /* If the reconnect failed, then just clear the chain */ pwarn("Error reconnecting chain - clearing\n"); mod &= ~FSFATAL; next = RB_NEXT(FSCK_MSDOS_CACHE,0,fat); clearchain(boot,fat,fat->head); mod |= FSFATMOD; fat = next; continue; } if (ret == FSERROR && ask(1, "Clear")) { next = RB_NEXT(FSCK_MSDOS_CACHE,0,fat); clearchain(boot, fat, fat->head); mod |= FSFATMOD; fat = next; continue; } fat = RB_NEXT(FSCK_MSDOS_CACHE,0,fat); } finishlf(); fsck_debug("Verify Filesystem information\n"); //verify the fs infomation if (boot->FSInfo){ ret = 0; if (boot->FSFree != boot->NumFree) { pwarn("Free space in FSInfo block (%d) not correct (%d)\n", boot->FSFree, boot->NumFree); if (ask(1, "Fix")) { boot->FSFree = boot->NumFree; ret = 1; } } if (boot->NumFree) { if ((boot->FSNext >= boot->NumClusters)) { pwarn("Next free cluster in FSInfo block out of range\n"); if (ask(1, "Fix")){ boot->FSNext = firstfreecl; ret = 1; } } } if (boot->FSNext > boot->NumClusters || boot->FSNext < CLUST_FIRST) { pwarn("FSNext block (%d) not correct NumClusters (%d)\n", boot->FSNext, boot->NumClusters); boot->FSNext=CLUST_FIRST; // boot->FSNext can have -1 value. } if (ret) mod |= writefsinfo(dosfs, boot); } return mod; }