busybox/util-linux/volume_id/fat.c
Denis Vlasenko c5b737231d volude_id: remove unused fields and functions which were setting them
function                                             old     new   delta
uuidcache_init                                       567     704    +137
findfs_main                                            -     125    +125
packed_usage                                       23662   23694     +32
static.drive_name_string                               -      14     +14
applet_names                                        1815    1822      +7
applet_main                                         1104    1108      +4
volume_id_open_node                                   35      38      +3
applet_nameofs                                       552     554      +2
get_devname_from_label                                78      79      +1
applet_install_loc                                   138     139      +1
volume_id_set_label_unicode16                         31      27      -4
volume_id_set_label_string                            74      70      -4
get_devname_from_uuid                                 63      59      -4
fs1                                                   12       8      -4
volume_id_set_unicode16                              209     202      -7
volume_id_free_buffer                                 71      56     -15
free_volume_id                                        52      37     -15
volume_id_probe_luks                                  97      79     -18
volume_id_set_usage_part                              21       -     -21
volume_id_probe_ufs                                  148     126     -22
volume_id_probe_lsi_mega_raid                        131     108     -23
volume_id_probe_highpoint_45x_raid                   127     104     -23
volume_id_probe_highpoint_37x_raid                    87      63     -24
volume_id_set_usage                                   28       -     -28
volume_id_probe_romfs                                121      93     -28
volume_id_set_label_raw                               30       -     -30
volume_id_probe_promise_fasttrack_raid               174     144     -30
volume_id_set_uuid                                   373     342     -31
volume_id_probe_xfs                                  122      91     -31
volume_id_probe_jfs                                  138     107     -31
volume_id_probe_ocfs2                                139     107     -32
volume_id_probe_lvm1                                  90      58     -32
volume_id_probe_cramfs                               106      63     -43
volume_id_probe_via_raid                             145     101     -44
volume_id_probe_intel_software_raid                  153     108     -45
volume_id_probe_minix                                121      74     -47
volume_id_probe_udf                                  682     632     -50
volume_id_probe_nvidia_raid                          158     108     -50
volume_id_probe_lvm2                                 128      78     -50
volume_id_probe_hpfs                                 117      67     -50
volume_id_probe_ext                                  143      93     -50
volume_id_probe_linux_raid                           191     139     -52
volume_id_probe_sysv                                 244     187     -57
volume_id_probe_silicon_medley_raid                  158      97     -61
usage_to_string                                       64       -     -64
volume_id_probe_linux_swap                           263     198     -65
volume_id_get_buffer                                 372     307     -65
volume_id_probe_iso9660                              412     332     -80
volume_id_probe_hfs_hfsplus                          888     806     -82
volume_id_probe_ntfs                                 396     294    -102
volume_id_probe_vfat                                 980     872    -108
volume_id_probe_reiserfs                             417     268    -149
dev_get_major_minor                                  175       -    -175
uuidcache_check_device                               692     499    -193
volume_id_probe_mac_partition_map                    697       -    -697
------------------------------------------------------------------------------
(add/remove: 2/6 grow/shrink: 8/39 up/down: 326/-2836)      Total: -2510 bytes
   text    data     bss     dec     hex filename
 797220     662    7420  805302   c49b6 busybox_old
 794244     662    7420  802326   c3e16 busybox_unstripped
2008-03-17 09:21:26 +00:00

336 lines
8.8 KiB
C

/*
* volume_id - reads filesystem label and uuid
*
* Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "volume_id_internal.h"
#define FAT12_MAX 0xff5
#define FAT16_MAX 0xfff5
#define FAT_ATTR_VOLUME_ID 0x08
#define FAT_ATTR_DIR 0x10
#define FAT_ATTR_LONG_NAME 0x0f
#define FAT_ATTR_MASK 0x3f
#define FAT_ENTRY_FREE 0xe5
struct vfat_super_block {
uint8_t boot_jump[3];
uint8_t sysid[8];
uint16_t sector_size;
uint8_t sectors_per_cluster;
uint16_t reserved;
uint8_t fats;
uint16_t dir_entries;
uint16_t sectors;
uint8_t media;
uint16_t fat_length;
uint16_t secs_track;
uint16_t heads;
uint32_t hidden;
uint32_t total_sect;
union {
struct fat_super_block {
uint8_t unknown[3];
uint8_t serno[4];
uint8_t label[11];
uint8_t magic[8];
uint8_t dummy2[192];
uint8_t pmagic[2];
} __attribute__((__packed__)) fat;
struct fat32_super_block {
uint32_t fat32_length;
uint16_t flags;
uint8_t version[2];
uint32_t root_cluster;
uint16_t insfo_sector;
uint16_t backup_boot;
uint16_t reserved2[6];
uint8_t unknown[3];
uint8_t serno[4];
uint8_t label[11];
uint8_t magic[8];
uint8_t dummy2[164];
uint8_t pmagic[2];
} __attribute__((__packed__)) fat32;
} __attribute__((__packed__)) type;
} __attribute__((__packed__));
struct vfat_dir_entry {
uint8_t name[11];
uint8_t attr;
uint16_t time_creat;
uint16_t date_creat;
uint16_t time_acc;
uint16_t date_acc;
uint16_t cluster_high;
uint16_t time_write;
uint16_t date_write;
uint16_t cluster_low;
uint32_t size;
} __attribute__((__packed__));
static uint8_t *get_attr_volume_id(struct vfat_dir_entry *dir, unsigned count)
{
unsigned i;
for (i = 0; i < count; i++) {
/* end marker */
if (dir[i].name[0] == 0x00) {
dbg("end of dir");
break;
}
/* empty entry */
if (dir[i].name[0] == FAT_ENTRY_FREE)
continue;
/* long name */
if ((dir[i].attr & FAT_ATTR_MASK) == FAT_ATTR_LONG_NAME)
continue;
if ((dir[i].attr & (FAT_ATTR_VOLUME_ID | FAT_ATTR_DIR)) == FAT_ATTR_VOLUME_ID) {
/* labels do not have file data */
if (dir[i].cluster_high != 0 || dir[i].cluster_low != 0)
continue;
dbg("found ATTR_VOLUME_ID id in root dir");
return dir[i].name;
}
dbg("skip dir entry");
}
return NULL;
}
int volume_id_probe_vfat(struct volume_id *id, uint64_t off)
{
struct vfat_super_block *vs;
struct vfat_dir_entry *dir;
uint16_t sector_size;
uint16_t dir_entries;
uint32_t sect_count;
uint16_t reserved;
uint32_t fat_size;
uint32_t root_cluster;
uint32_t dir_size;
uint32_t cluster_count;
uint32_t fat_length;
uint64_t root_start;
uint32_t start_data_sect;
uint16_t root_dir_entries;
uint8_t *buf;
uint32_t buf_size;
uint8_t *label = NULL;
uint32_t next;
int maxloop;
dbg("probing at offset 0x%llx", (unsigned long long) off);
vs = volume_id_get_buffer(id, off, 0x200);
if (vs == NULL)
return -1;
/* believe only that's fat, don't trust the version
* the cluster_count will tell us
*/
if (memcmp(vs->sysid, "NTFS", 4) == 0)
return -1;
if (memcmp(vs->type.fat32.magic, "MSWIN", 5) == 0)
goto valid;
if (memcmp(vs->type.fat32.magic, "FAT32 ", 8) == 0)
goto valid;
if (memcmp(vs->type.fat.magic, "FAT16 ", 8) == 0)
goto valid;
if (memcmp(vs->type.fat.magic, "MSDOS", 5) == 0)
goto valid;
if (memcmp(vs->type.fat.magic, "FAT12 ", 8) == 0)
goto valid;
/*
* There are old floppies out there without a magic, so we check
* for well known values and guess if it's a fat volume
*/
/* boot jump address check */
if ((vs->boot_jump[0] != 0xeb || vs->boot_jump[2] != 0x90) &&
vs->boot_jump[0] != 0xe9)
return -1;
/* heads check */
if (vs->heads == 0)
return -1;
/* cluster size check*/
if (vs->sectors_per_cluster == 0 ||
(vs->sectors_per_cluster & (vs->sectors_per_cluster-1)))
return -1;
/* media check */
if (vs->media < 0xf8 && vs->media != 0xf0)
return -1;
/* fat count*/
if (vs->fats != 2)
return -1;
valid:
/* sector size check */
sector_size = le16_to_cpu(vs->sector_size);
if (sector_size != 0x200 && sector_size != 0x400 &&
sector_size != 0x800 && sector_size != 0x1000)
return -1;
dbg("sector_size 0x%x", sector_size);
dbg("sectors_per_cluster 0x%x", vs->sectors_per_cluster);
dir_entries = le16_to_cpu(vs->dir_entries);
reserved = le16_to_cpu(vs->reserved);
dbg("reserved 0x%x", reserved);
sect_count = le16_to_cpu(vs->sectors);
if (sect_count == 0)
sect_count = le32_to_cpu(vs->total_sect);
dbg("sect_count 0x%x", sect_count);
fat_length = le16_to_cpu(vs->fat_length);
if (fat_length == 0)
fat_length = le32_to_cpu(vs->type.fat32.fat32_length);
dbg("fat_length 0x%x", fat_length);
fat_size = fat_length * vs->fats;
dir_size = ((dir_entries * sizeof(struct vfat_dir_entry)) +
(sector_size-1)) / sector_size;
dbg("dir_size 0x%x", dir_size);
cluster_count = sect_count - (reserved + fat_size + dir_size);
cluster_count /= vs->sectors_per_cluster;
dbg("cluster_count 0x%x", cluster_count);
// if (cluster_count < FAT12_MAX) {
// strcpy(id->type_version, "FAT12");
// } else if (cluster_count < FAT16_MAX) {
// strcpy(id->type_version, "FAT16");
// } else {
// strcpy(id->type_version, "FAT32");
// goto fat32;
// }
if (cluster_count >= FAT16_MAX)
goto fat32;
/* the label may be an attribute in the root directory */
root_start = (reserved + fat_size) * sector_size;
dbg("root dir start 0x%llx", (unsigned long long) root_start);
root_dir_entries = le16_to_cpu(vs->dir_entries);
dbg("expected entries 0x%x", root_dir_entries);
buf_size = root_dir_entries * sizeof(struct vfat_dir_entry);
buf = volume_id_get_buffer(id, off + root_start, buf_size);
if (buf == NULL)
goto found;
dir = (struct vfat_dir_entry*) buf;
label = get_attr_volume_id(dir, root_dir_entries);
vs = volume_id_get_buffer(id, off, 0x200);
if (vs == NULL)
return -1;
if (label != NULL && memcmp(label, "NO NAME ", 11) != 0) {
// volume_id_set_label_raw(id, label, 11);
volume_id_set_label_string(id, label, 11);
} else if (memcmp(vs->type.fat.label, "NO NAME ", 11) != 0) {
// volume_id_set_label_raw(id, vs->type.fat.label, 11);
volume_id_set_label_string(id, vs->type.fat.label, 11);
}
volume_id_set_uuid(id, vs->type.fat.serno, UUID_DOS);
goto found;
fat32:
/* FAT32 root dir is a cluster chain like any other directory */
buf_size = vs->sectors_per_cluster * sector_size;
root_cluster = le32_to_cpu(vs->type.fat32.root_cluster);
dbg("root dir cluster %u", root_cluster);
start_data_sect = reserved + fat_size;
next = root_cluster;
maxloop = 100;
while (--maxloop) {
uint32_t next_sect_off;
uint64_t next_off;
uint64_t fat_entry_off;
int count;
dbg("next cluster %u", next);
next_sect_off = (next - 2) * vs->sectors_per_cluster;
next_off = (start_data_sect + next_sect_off) * sector_size;
dbg("cluster offset 0x%llx", (unsigned long long) next_off);
/* get cluster */
buf = volume_id_get_buffer(id, off + next_off, buf_size);
if (buf == NULL)
goto found;
dir = (struct vfat_dir_entry*) buf;
count = buf_size / sizeof(struct vfat_dir_entry);
dbg("expected entries 0x%x", count);
label = get_attr_volume_id(dir, count);
if (label)
break;
/* get FAT entry */
fat_entry_off = (reserved * sector_size) + (next * sizeof(uint32_t));
buf = volume_id_get_buffer(id, off + fat_entry_off, buf_size);
if (buf == NULL)
goto found;
/* set next cluster */
next = le32_to_cpu(*((uint32_t *) buf) & 0x0fffffff);
if (next == 0)
break;
}
if (maxloop == 0)
dbg("reached maximum follow count of root cluster chain, give up");
vs = volume_id_get_buffer(id, off, 0x200);
if (vs == NULL)
return -1;
if (label != NULL && memcmp(label, "NO NAME ", 11) != 0) {
// volume_id_set_label_raw(id, label, 11);
volume_id_set_label_string(id, label, 11);
} else if (memcmp(vs->type.fat32.label, "NO NAME ", 11) != 0) {
// volume_id_set_label_raw(id, vs->type.fat32.label, 11);
volume_id_set_label_string(id, vs->type.fat32.label, 11);
}
volume_id_set_uuid(id, vs->type.fat32.serno, UUID_DOS);
found:
// volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
// id->type = "vfat";
return 0;
}