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authorH. Peter Anvin <hpa@zytor.com>2010-01-24 16:55:22 -0800
committerH. Peter Anvin <hpa@zytor.com>2010-01-24 16:55:22 -0800
commit21ec7e06f96074a6dce3a256120e58a770bb7b1e (patch)
tree395e5719cf4dd2bbe9e3357055db38b095d93888 /libinstaller
parent42f0218e808c37e08cdb12e99b80a3c9b437cd37 (diff)
downloadsyslinux-21ec7e06f96074a6dce3a256120e58a770bb7b1e.tar.gz
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FAT: be more explicit why we think a filesystem is bad
Give readable error messages as to why we think a filesystem is bad. Given the current sizes of the installer, these extra strings are worth it. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'libinstaller')
-rw-r--r--libinstaller/syslxmod.c35
1 files changed, 21 insertions, 14 deletions
diff --git a/libinstaller/syslxmod.c b/libinstaller/syslxmod.c
index 9e1da440..88de375f 100644
--- a/libinstaller/syslxmod.c
+++ b/libinstaller/syslxmod.c
@@ -52,19 +52,20 @@ const char *syslinux_check_bootsect(const void *bs)
/* Must be 0xF0 or 0xF8..0xFF */
if (get_8(&sectbuf->bsMedia) != 0xF0 && get_8(&sectbuf->bsMedia) < 0xF8)
- goto invalid;
+ return "invalid media signature (not a FAT filesystem?)";
sectorsize = get_16(&sectbuf->bsBytesPerSec);
- if (sectorsize == SECTOR_SIZE) ; /* ok */
+ if (sectorsize == SECTOR_SIZE)
+ ; /* ok */
else if (sectorsize >= 512 && sectorsize <= 4096 &&
(sectorsize & (sectorsize - 1)) == 0)
return "unsupported sectors size";
else
- goto invalid;
+ return "impossible sector size";
clustersize = get_8(&sectbuf->bsSecPerClust);
if (clustersize == 0 || (clustersize & (clustersize - 1)))
- goto invalid; /* Must be nonzero and a power of 2 */
+ return "impossible cluster size";
sectors = get_16(&sectbuf->bsSectors);
sectors = sectors ? sectors : get_32(&sectbuf->bsHugeSectors);
@@ -79,8 +80,11 @@ const char *syslinux_check_bootsect(const void *bs)
rootdirents = get_16(&sectbuf->bsRootDirEnts);
dsectors -= (rootdirents + sectorsize / 32 - 1) / sectorsize;
- if (dsectors < 0 || fatsectors == 0)
- goto invalid;
+ if (dsectors < 0)
+ return "negative number of data sectors";
+
+ if (fatsectors == 0)
+ return "zero FAT sectors";
clusters = dsectors / clustersize;
@@ -88,7 +92,7 @@ const char *syslinux_check_bootsect(const void *bs)
/* FAT12 or FAT16 */
if (!get_16(&sectbuf->bsFATsecs))
- goto invalid;
+ return "zero FAT sectors (FAT12/16)";
if (get_8(&sectbuf->bs16.BootSignature) == 0x29) {
if (!memcmp(&sectbuf->bs16.FileSysType, "FAT12 ", 8)) {
@@ -97,6 +101,8 @@ const char *syslinux_check_bootsect(const void *bs)
} else if (!memcmp(&sectbuf->bs16.FileSysType, "FAT16 ", 8)) {
if (clusters < 0xFF5)
return "less than 4084 clusters but claims FAT16";
+ } else if (!memcmp(&sectbuf->bs16.FileSysType, "FAT32 ", 8)) {
+ return "less than 65525 clusters but claims FAT32";
} else if (memcmp(&sectbuf->bs16.FileSysType, "FAT ", 8)) {
static char fserr[] =
"filesystem type \"????????\" not supported";
@@ -105,19 +111,20 @@ const char *syslinux_check_bootsect(const void *bs)
}
}
} else if (clusters < 0x0FFFFFF5) {
- /* FAT32 */
- /* Moving the FileSysType and BootSignature was a lovely stroke of M$ idiocy */
+ /*
+ * FAT32...
+ *
+ * Moving the FileSysType and BootSignature was a lovely stroke
+ * of M$ idiocy...
+ */
if (get_8(&sectbuf->bs32.BootSignature) != 0x29 ||
memcmp(&sectbuf->bs32.FileSysType, "FAT32 ", 8))
- goto invalid;
+ return "missing FAT32 signature";
} else {
- goto invalid;
+ return "impossibly large number of clusters";
}
return NULL;
-
-invalid:
- return "this doesn't look like a valid FAT filesystem";
}
/*