Date: Sun, 15 Sep 2019 19:41:54 +0000 (UTC) From: Xin LI <delphij@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r352364 - head/sbin/fsck_msdosfs Message-ID: <201909151941.x8FJfsVf019366@repo.freebsd.org>
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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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