diff options
Diffstat (limited to 'fat.c')
| -rw-r--r-- | fat.c | 43 |
1 files changed, 36 insertions, 7 deletions
@@ -449,7 +449,7 @@ tryclear(struct bootblock *boot, struct fatEntry *fat, cl_t head, cl_t *trunc) int checkfat(struct bootblock *boot, struct fatEntry *fat) { - cl_t head, p, h, n; + cl_t head, p, h, n, wdk; u_int len; int ret = 0; int conf; @@ -466,8 +466,14 @@ checkfat(struct bootblock *boot, struct fatEntry *fat) /* follow the chain and mark all clusters on the way */ for (len = 0, p = head; - p >= CLUST_FIRST && p < boot->NumClusters; - p = fat[p].next) { + p >= CLUST_FIRST && p < boot->NumClusters; + p = fat[p].next) { + /* we have to check the len, to avoid infinite loop */ + if (len > boot->NumClusters) { + printf("detect cluster chain loop: head %u for p %u\n", head, p); + break; + } + fat[p].head = head; len++; } @@ -487,11 +493,14 @@ checkfat(struct bootblock *boot, struct fatEntry *fat) continue; /* follow the chain to its end (hopefully) */ - for (p = head; - (n = fat[p].next) >= CLUST_FIRST && n < boot->NumClusters; - p = n) + /* also possible infinite loop, that's why I insert wdk counter */ + for (p = head,wdk=boot->NumClusters; + (n = fat[p].next) >= CLUST_FIRST && n < boot->NumClusters && wdk; + p = n,wdk--) { if (fat[n].head != head) break; + } + if (n >= CLUST_EOFS) continue; @@ -692,6 +701,7 @@ checklost(int dosfs, struct bootblock *boot, struct fatEntry *fat) ret = 1; } } + if (boot->NumFree) { if ((boot->FSNext >= boot->NumClusters) || (fat[boot->FSNext].next != CLUST_FREE)) { pwarn("Next free cluster in FSInfo block (%u) not free\n", @@ -704,7 +714,26 @@ checklost(int dosfs, struct bootblock *boot, struct fatEntry *fat) break; } } - } + } + + if (boot->FSNext > boot->NumClusters ) { + pwarn("FSNext block (%d) not correct NumClusters (%d)\n", + boot->FSNext, boot->NumClusters); + boot->FSNext=CLUST_FIRST; // boot->FSNext can have -1 value. + } + + if (boot->NumFree && fat[boot->FSNext].next != CLUST_FREE) { + pwarn("Next free cluster in FSInfo block (%u) not free\n", + boot->FSNext); + 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); } |