Author: delphij
Date: Sun Sep 15 19:41:54 2019
New Revision: 352364
URL: https://svnweb.freebsd.org/changeset/base/352364
Log:
Avoid mixing cluster numbers and sector numbers. Makes code more readable.
Obtained from: NetBSD
MFC after: 2 weeks
Modified:
head/sbin/fsck_msdosfs/boot.c
head/sbin/fsck_msdosfs/dir.c
head/sbin/fsck_msdosfs/dosfs.h
Modified: head/sbin/fsck_msdosfs/boot.c
==============================================================================
--- head/sbin/fsck_msdosfs/boot.c Sun Sep 15 19:38:15 2019
(r352363)
+++ head/sbin/fsck_msdosfs/boot.c Sun Sep 15 19:41:54 2019
(r352364)
@@ -259,12 +259,18 @@ readboot(int dosfs, struct bootblock *boot)
return FSFATAL;
}
- boot->ClusterOffset = (boot->bpbRootDirEnts * 32 +
+ boot->FirstCluster = (boot->bpbRootDirEnts * 32 +
boot->bpbBytesPerSec - 1) / boot->bpbBytesPerSec +
- boot->bpbResSectors + boot->bpbFATs * boot->FATsecs -
- CLUST_FIRST * boot->bpbSecPerClust;
- boot->NumClusters = (boot->NumSectors - boot->ClusterOffset) /
- boot->bpbSecPerClust;
+ boot->bpbResSectors + boot->bpbFATs * boot->FATsecs;
+
+ if (boot->FirstCluster + boot->bpbSecPerClust > boot->NumSectors) {
+ pfatal("Cluster offset too large (%u clusters)\n",
+ boot->FirstCluster);
+ return FSFATAL;
+ }
+
+ boot->NumClusters = (boot->NumSectors - boot->FirstCluster) /
boot->bpbSecPerClust +
+ CLUST_FIRST;
if (boot->flags & FAT32)
boot->ClustMask = CLUST32_MASK;
Modified: head/sbin/fsck_msdosfs/dir.c
==============================================================================
--- head/sbin/fsck_msdosfs/dir.c Sun Sep 15 19:38:15 2019
(r352363)
+++ head/sbin/fsck_msdosfs/dir.c Sun Sep 15 19:41:54 2019
(r352364)
@@ -317,7 +317,8 @@ delete(int f, struct bootblock *boot, struct fatEntry
break;
e = delbuf + endoff;
}
- off = startcl * boot->bpbSecPerClust + boot->ClusterOffset;
+ off = (startcl - CLUST_FIRST) * boot->bpbSecPerClust +
boot->FirstCluster;
+
off *= boot->bpbBytesPerSec;
if (lseek(f, off, SEEK_SET) != off) {
perr("Unable to lseek to %" PRId64, off);
@@ -457,7 +458,7 @@ check_subdirectory(int f, struct bootblock *boot, stru
off = boot->bpbResSectors + boot->bpbFATs *
boot->FATsecs;
} else {
- off = cl * boot->bpbSecPerClust + boot->ClusterOffset;
+ off = (cl - CLUST_FIRST) * boot->bpbSecPerClust +
boot->FirstCluster;
}
/*
@@ -538,7 +539,7 @@ readDosDirSection(int f, struct bootblock *boot, struc
boot->FATsecs;
} else {
last = boot->bpbSecPerClust * boot->bpbBytesPerSec;
- off = cl * boot->bpbSecPerClust + boot->ClusterOffset;
+ off = (cl - CLUST_FIRST) * boot->bpbSecPerClust +
boot->FirstCluster;
}
off *= boot->bpbBytesPerSec;
@@ -1069,8 +1070,9 @@ reconnect(int dosfs, struct bootblock *boot, struct fa
lfcl = (lostDir->head < boot->NumClusters) ?
lostDir->head : 0;
return FSERROR;
}
- lfoff = lfcl * boot->ClusterSize
- + boot->ClusterOffset * boot->bpbBytesPerSec;
+ lfoff = (lfcl - CLUST_FIRST) * boot->ClusterSize
+ + boot->FirstCluster * boot->bpbBytesPerSec;
+
if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
|| (size_t)read(dosfs, lfbuf, boot->ClusterSize) !=
boot->ClusterSize) {
perr("could not read LOST.DIR");
Modified: head/sbin/fsck_msdosfs/dosfs.h
==============================================================================
--- head/sbin/fsck_msdosfs/dosfs.h Sun Sep 15 19:38:15 2019
(r352363)
+++ head/sbin/fsck_msdosfs/dosfs.h Sun Sep 15 19:41:54 2019
(r352364)
@@ -74,7 +74,7 @@ struct bootblock {
u_int32_t NumSectors; /* how many sectors are there */
u_int32_t FATsecs; /* how many sectors are in FAT */
u_int32_t NumFatEntries; /* how many entries really are there */
- u_int ClusterOffset; /* at what sector would sector 0 start
*/
+ u_int FirstCluster; /* at what sector is Cluster
CLUST_FIRST */
u_int ClusterSize; /* Cluster size in bytes */
/* Now some statistics: */
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