static void
g_label_msdosfs_taste(struct g_consumer *cp, char *label, size_t size)
{
struct g_provider *pp;
FAT_BSBPB *pfat_bsbpb;
FAT32_BSBPB *pfat32_bsbpb;
FAT_DES *pfat_entry;
uint8_t *sector0, *sector;
g_topology_assert_not();
pp = cp->provider;
sector0 = NULL;
sector = NULL;
bzero(label, size);
/* Check if the sector size of the medium is a valid FAT sector size. */
switch(pp->sectorsize) {
case 512:
case 1024:
case 2048:
case 4096:
break;
default:
G_LABEL_DEBUG(1, "MSDOSFS: %s: sector size %d not compatible.",
pp->name, pp->sectorsize);
return;
}
/* Load 1st sector with boot sector and boot parameter block. */
sector0 = (uint8_t *)g_read_data(cp, 0, pp->sectorsize, NULL);
if (sector0 == NULL)
return;
/* Check for the FAT boot sector signature. */
if (sector0[510] != 0x55 || sector0[511] != 0xaa) {
G_LABEL_DEBUG(1, "MSDOSFS: %s: no FAT signature found.",
pp->name);
goto error;
}
/*
* Test if this is really a FAT volume and determine the FAT type.
*/
pfat_bsbpb = (FAT_BSBPB *)sector0;
pfat32_bsbpb = (FAT32_BSBPB *)sector0;
if (UINT16BYTES(pfat_bsbpb->BPB_FATSz16) != 0) {
/*
* If the BPB_FATSz16 field is not zero and the string "FAT" is
* at the right place, this should be a FAT12 or FAT16 volume.
*/
if (strncmp(pfat_bsbpb->BS_FilSysType, "FAT", 3) != 0) {
G_LABEL_DEBUG(1,
"MSDOSFS: %s: FAT12/16 volume not valid.",
pp->name);
goto error;
}
G_LABEL_DEBUG(1, "MSDOSFS: %s: FAT12/FAT16 volume detected.",
pp->name);
/* A volume with no name should have "NO NAME " as label. */
if (strncmp(pfat_bsbpb->BS_VolLab, LABEL_NO_NAME,
sizeof(pfat_bsbpb->BS_VolLab)) == 0) {
G_LABEL_DEBUG(1,
"MSDOSFS: %s: FAT12/16 volume has no name.",
pp->name);
goto error;
}
strlcpy(label, pfat_bsbpb->BS_VolLab,
MIN(size, sizeof(pfat_bsbpb->BS_VolLab) + 1));
} else if (UINT32BYTES(pfat32_bsbpb->BPB_FATSz32) != 0) {
uint32_t fat_FirstDataSector, fat_BytesPerSector, offset;
/*
* If the BPB_FATSz32 field is not zero and the string "FAT" is
* at the right place, this should be a FAT32 volume.
*/
if (strncmp(pfat32_bsbpb->BS_FilSysType, "FAT", 3) != 0) {
G_LABEL_DEBUG(1, "MSDOSFS: %s: FAT32 volume not valid.",
pp->name);
goto error;
}
G_LABEL_DEBUG(1, "MSDOSFS: %s: FAT32 volume detected.",
pp->name);
/*
* If the volume label is not "NO NAME " we're done.
*/
if (strncmp(pfat32_bsbpb->BS_VolLab, LABEL_NO_NAME,
sizeof(pfat32_bsbpb->BS_VolLab)) != 0) {
strlcpy(label, pfat32_bsbpb->BS_VolLab,
MIN(size, sizeof(pfat32_bsbpb->BS_VolLab) + 1));
goto endofchecks;
}
/*
* If the volume label "NO NAME " is in the boot sector, the
* label of FAT32 volumes may be stored as a special entry in
* the root directory.
*/
fat_FirstDataSector =
UINT16BYTES(pfat32_bsbpb->BPB_RsvdSecCnt) +
(pfat32_bsbpb->BPB_NumFATs *
UINT32BYTES(pfat32_bsbpb->BPB_FATSz32));
fat_BytesPerSector = UINT16BYTES(pfat32_bsbpb->BPB_BytsPerSec);
G_LABEL_DEBUG(2,
"MSDOSFS: FAT_FirstDataSector=0x%x, FAT_BytesPerSector=%d",
fat_FirstDataSector, fat_BytesPerSector);
for (offset = fat_BytesPerSector * fat_FirstDataSector;;
offset += fat_BytesPerSector) {
sector = (uint8_t *)g_read_data(cp, offset,
fat_BytesPerSector, NULL);
if (sector == NULL)
goto error;
pfat_entry = (FAT_DES *)sector;
do {
/* No more entries available. */
if (pfat_entry->DIR_Name[0] == 0) {
G_LABEL_DEBUG(1, "MSDOSFS: %s: "
"FAT32 volume has no name.",
pp->name);
goto error;
}
/* Skip empty or long name entries. */
if (pfat_entry->DIR_Name[0] == 0xe5 ||
(pfat_entry->DIR_Attr &
FAT_DES_ATTR_LONG_NAME) ==
FAT_DES_ATTR_LONG_NAME) {
continue;
}
/*
* The name of the entry is the volume label if
* ATTR_VOLUME_ID is set.
*/
if (pfat_entry->DIR_Attr &
FAT_DES_ATTR_VOLUME_ID) {
strlcpy(label, pfat_entry->DIR_Name,
MIN(size,
sizeof(pfat_entry->DIR_Name) + 1));
goto endofchecks;
}
} while((uint8_t *)(++pfat_entry) <
(uint8_t *)(sector + fat_BytesPerSector));
g_free(sector);
}
} else {
G_LABEL_DEBUG(1, "MSDOSFS: %s: no FAT volume detected.",
pp->name);
goto error;
}
endofchecks:
g_label_rtrim(label, size);
error:
if (sector0 != NULL)
g_free(sector0);
if (sector != NULL)
g_free(sector);
}
int
fstyp_msdosfs(FILE *fp, char *label, size_t size)
{
FAT_BSBPB *pfat_bsbpb;
FAT32_BSBPB *pfat32_bsbpb;
FAT_DES *pfat_entry;
uint8_t *sector0, *sector;
sector0 = NULL;
sector = NULL;
/* Load 1st sector with boot sector and boot parameter block. */
sector0 = (uint8_t *)read_buf(fp, 0, 512);
if (sector0 == NULL)
return (1);
/* Check for the FAT boot sector signature. */
if (sector0[510] != 0x55 || sector0[511] != 0xaa) {
goto error;
}
/*
* Test if this is really a FAT volume and determine the FAT type.
*/
pfat_bsbpb = (FAT_BSBPB *)sector0;
pfat32_bsbpb = (FAT32_BSBPB *)sector0;
if (UINT16BYTES(pfat_bsbpb->BPB_FATSz16) != 0) {
/*
* If the BPB_FATSz16 field is not zero and the string "FAT" is
* at the right place, this should be a FAT12 or FAT16 volume.
*/
if (strncmp(pfat_bsbpb->BS_FilSysType, "FAT", 3) != 0) {
goto error;
}
/* A volume with no name should have "NO NAME " as label. */
if (strncmp(pfat_bsbpb->BS_VolLab, LABEL_NO_NAME,
sizeof(pfat_bsbpb->BS_VolLab)) == 0) {
goto endofchecks;
}
strlcpy(label, pfat_bsbpb->BS_VolLab,
MIN(size, sizeof(pfat_bsbpb->BS_VolLab) + 1));
} else if (UINT32BYTES(pfat32_bsbpb->BPB_FATSz32) != 0) {
uint32_t fat_FirstDataSector, fat_BytesPerSector, offset;
/*
* If the BPB_FATSz32 field is not zero and the string "FAT" is
* at the right place, this should be a FAT32 volume.
*/
if (strncmp(pfat32_bsbpb->BS_FilSysType, "FAT", 3) != 0) {
goto error;
}
/*
* If the volume label is not "NO NAME " we're done.
*/
if (strncmp(pfat32_bsbpb->BS_VolLab, LABEL_NO_NAME,
sizeof(pfat32_bsbpb->BS_VolLab)) != 0) {
strlcpy(label, pfat32_bsbpb->BS_VolLab,
MIN(size, sizeof(pfat32_bsbpb->BS_VolLab) + 1));
goto endofchecks;
}
/*
* If the volume label "NO NAME " is in the boot sector, the
* label of FAT32 volumes may be stored as a special entry in
* the root directory.
*/
fat_FirstDataSector =
UINT16BYTES(pfat32_bsbpb->BPB_RsvdSecCnt) +
(pfat32_bsbpb->BPB_NumFATs *
UINT32BYTES(pfat32_bsbpb->BPB_FATSz32));
fat_BytesPerSector = UINT16BYTES(pfat32_bsbpb->BPB_BytsPerSec);
// fat_FirstDataSector, fat_BytesPerSector);
for (offset = fat_BytesPerSector * fat_FirstDataSector;;
offset += fat_BytesPerSector) {
sector = (uint8_t *)read_buf(fp, offset, fat_BytesPerSector);
if (sector == NULL)
goto error;
pfat_entry = (FAT_DES *)sector;
do {
/* No more entries available. */
if (pfat_entry->DIR_Name[0] == 0) {
goto endofchecks;
}
/* Skip empty or long name entries. */
if (pfat_entry->DIR_Name[0] == 0xe5 ||
(pfat_entry->DIR_Attr &
FAT_DES_ATTR_LONG_NAME) ==
FAT_DES_ATTR_LONG_NAME) {
continue;
}
/*
* The name of the entry is the volume label if
* ATTR_VOLUME_ID is set.
*/
if (pfat_entry->DIR_Attr &
FAT_DES_ATTR_VOLUME_ID) {
strlcpy(label, pfat_entry->DIR_Name,
MIN(size,
sizeof(pfat_entry->DIR_Name) + 1));
goto endofchecks;
}
} while((uint8_t *)(++pfat_entry) <
(uint8_t *)(sector + fat_BytesPerSector));
free(sector);
}
} else {
goto error;
}
endofchecks:
rtrim(label, size);
free(sector0);
free(sector);
return (0);
error:
free(sector0);
free(sector);
return (1);
}
