/*
* volume_id - reads filesystem label and uuid
*
- * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2004-2007 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2007 Ryan Lortie <desrt@desrt.ca>
*
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation version 2 of the License.
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
-#ifdef HAVE_CONFIG_H
-# include <config.h>
-#endif
-
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include "libvolume_id.h"
-#include "util.h"
+#include "libvolume_id-private.h"
#define FAT12_MAX 0xff5
#define FAT16_MAX 0xfff5
#define FAT_ATTR_MASK 0x3f
#define FAT_ENTRY_FREE 0xe5
+#define VFAT_LFN_SEQ_MASK 0x3f
+#define VFAT_LFN_SEQ_LAST 0x40
+#define VFAT_LFN_SEQ_MAX 20
+#define VFAT_LFN_CHARS_PER_ENTRY (5 + 6 + 2)
+#define VFAT_LOWERCASE_NAME 0x10
+#define VFAT_LOWERCASE_EXT 0x08
+
struct vfat_super_block {
uint8_t boot_jump[3];
uint8_t sysid[8];
struct vfat_dir_entry {
uint8_t name[11];
uint8_t attr;
+ uint8_t lowercase;
+ uint8_t fine_time_creat;
uint16_t time_creat;
uint16_t date_creat;
- uint16_t time_acc;
uint16_t date_acc;
uint16_t cluster_high;
uint16_t time_write;
uint32_t size;
} PACKED;
-static uint8_t *get_attr_volume_id(struct vfat_dir_entry *dir, unsigned int count)
+
+struct vfat_lfn_entry {
+ uint8_t seq;
+ uint16_t name0[5];
+ uint8_t attr;
+ uint8_t reserved;
+ uint8_t cksum;
+ uint16_t name1[6];
+ uint16_t cluster;
+ uint16_t name2[2];
+} PACKED;
+
+static uint8_t fat_lfn_checksum(const uint8_t name[11])
+{
+ uint8_t cksum = 0;
+ int i;
+
+ /* http://en.wikipedia.org/wiki/File_Allocation_Table */
+ for (i = 0; i < 11; i++)
+ cksum = ((cksum & 1) ? 0x80 : 0) + (cksum >> 1) + name[i];
+
+ return cksum;
+}
+
+static size_t fat_read_lfn(uint8_t *filename, size_t fnsize,
+ struct vfat_dir_entry *dir,
+ struct vfat_dir_entry *entry)
+{
+ uint8_t buffer[VFAT_LFN_SEQ_MAX * VFAT_LFN_CHARS_PER_ENTRY * 2];
+ uint8_t expected_seq = 1;
+ uint8_t cksum;
+ size_t len = 0;
+ size_t fnlen = 0;
+
+ cksum = fat_lfn_checksum(entry->name);
+
+ while (--entry >= dir) {
+ struct vfat_lfn_entry *lfn = (struct vfat_lfn_entry *) entry;
+
+ if (expected_seq > VFAT_LFN_SEQ_MAX)
+ break;
+
+ if ((lfn->attr & FAT_ATTR_MASK) != FAT_ATTR_LONG_NAME)
+ break;
+
+ if (lfn->cksum != cksum)
+ break;
+
+ if ((lfn->seq & VFAT_LFN_SEQ_MASK) != expected_seq++)
+ break;
+
+ if (lfn->cluster != 0)
+ break;
+
+ /* extra paranoia -- should never happen */
+ if (len + sizeof(lfn->name0) + sizeof(lfn->name1) +
+ sizeof(lfn->name2) > sizeof(buffer))
+ break;
+
+ memcpy (&buffer[len], lfn->name0, sizeof(lfn->name0));
+ len += sizeof(lfn->name0);
+ memcpy (&buffer[len], lfn->name1, sizeof(lfn->name1));
+ len += sizeof(lfn->name1);
+ memcpy (&buffer[len], lfn->name2, sizeof(lfn->name2));
+ len += sizeof(lfn->name2);
+
+ if (lfn->seq & VFAT_LFN_SEQ_LAST) {
+ fnlen = volume_id_set_unicode16(filename, fnsize, buffer, LE, len);
+ break;
+ }
+ }
+
+ return fnlen;
+}
+
+static size_t fat_read_filename(uint8_t *filename, size_t fnsize,
+ struct vfat_dir_entry *dir, struct vfat_dir_entry *entry)
+{
+ size_t len;
+ int i;
+
+ /* check if maybe we have LFN entries */
+ len = fat_read_lfn(filename, fnsize, dir, entry);
+ if (len > 0)
+ goto out;
+
+ /* else, read the normal 8.3 name */
+ for (i = 0; i < 11; i++) {
+ if (entry->lowercase & ((i < 8) ? VFAT_LOWERCASE_NAME : VFAT_LOWERCASE_EXT))
+ filename[i] = tolower(entry->name[i]);
+ else
+ filename[i] = entry->name[i];
+ }
+ len = 11;
+
+out:
+ filename[len] = '\0';
+ return len;
+}
+
+/* fills filename, returns string length */
+static size_t get_fat_attr_volume_id(uint8_t *filename, size_t fnsize,
+ struct vfat_dir_entry *dir, unsigned int count)
{
unsigned int i;
for (i = 0; i < count; i++) {
/* end marker */
if (dir[i].name[0] == 0x00) {
- dbg("end of dir");
+ dbg("end of dir\n");
break;
}
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("found ATTR_VOLUME_ID id in root dir\n");
+ return fat_read_filename(filename, fnsize, dir, &dir[i]);
}
- dbg("skip dir entry");
+ dbg("skip dir entry\n");
}
- return NULL;
+ return 0;
}
int volume_id_probe_vfat(struct volume_id *id, uint64_t off, uint64_t size)
{
+ uint8_t filename[255 * 3];
struct vfat_super_block *vs;
struct vfat_dir_entry *dir;
struct fat32_fsinfo *fsinfo;
uint16_t fsinfo_sect;
uint8_t *buf;
uint32_t buf_size;
- uint8_t *label = NULL;
uint32_t next;
int maxloop;
+ size_t fnlen;
- info("probing at offset 0x%llx", (unsigned long long) off);
+ info("probing at offset 0x%" PRIx64 "\n", off);
buf = volume_id_get_buffer(id, off, 0x400);
if (buf == NULL)
return -1;
- /* check signature */
- if (buf[510] != 0x55 || buf[511] != 0xaa)
- return -1;
-
vs = (struct vfat_super_block *) buf;
if (memcmp(vs->sysid, "NTFS", 4) == 0)
return -1;
if (memcmp(vs->type.fat.magic, "FAT12 ", 8) == 0)
goto magic;
+ /* check signature */
+ if (buf[510] != 0x55 || buf[511] != 0xaa)
+ return -1;
+
/* some old floppies don't have a magic, expect the boot jump address to match */
if ((vs->boot_jump[0] != 0xeb || vs->boot_jump[2] != 0x90) &&
vs->boot_jump[0] != 0xe9)
return -1;
magic:
+ info("magic found\n");
/* reserverd sector count */
if (!vs->reserved)
return -1;
- /* fat count*/
+ /* fat count */
if (!vs->fats)
return -1;
if (vs->media < 0xf8 && vs->media != 0xf0)
return -1;
- /* cluster size check*/
+ /* cluster size check */
if (vs->sectors_per_cluster == 0 ||
(vs->sectors_per_cluster & (vs->sectors_per_cluster-1)))
return -1;
/* sector size check */
sector_size = le16_to_cpu(vs->sector_size);
- if (sector_size != 0x200 && sector_size != 0x400 &&
- sector_size != 0x800 && sector_size != 0x1000)
+ if (sector_size == 0 || ((sector_size & (sector_size-1)) != 0))
return -1;
- dbg("sector_size 0x%x", sector_size);
- dbg("sectors_per_cluster 0x%x", vs->sectors_per_cluster);
+ info("checks passed\n");
+ dbg("sector_size 0x%x\n", sector_size);
+ dbg("sectors_per_cluster 0x%x\n", vs->sectors_per_cluster);
dir_entries = le16_to_cpu(vs->dir_entries);
reserved = le16_to_cpu(vs->reserved);
- dbg("reserved 0x%x", reserved);
+ dbg("reserved 0x%x\n", 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);
+ dbg("sect_count 0x%x\n", sect_count);
fat_length = le16_to_cpu(vs->fat_length);
- dbg("fat_length 0x%x", fat_length);
+ info("fat_length 0x%x\n", fat_length);
fat32_length = le32_to_cpu(vs->type.fat32.fat32_length);
- dbg("fat32_length 0x%x", fat32_length);
+ info("fat32_length 0x%x\n", fat32_length);
if (fat_length)
fat_size = fat_length * vs->fats;
fat_size = fat32_length * vs->fats;
else
return -1;
- dbg("fat_size 0x%x", fat_size);
+ info("fat_size 0x%x\n", fat_size);
dir_size = ((dir_entries * sizeof(struct vfat_dir_entry)) +
(sector_size-1)) / sector_size;
- dbg("dir_size 0x%x", dir_size);
+ info("dir_size 0x%x\n", dir_size);
cluster_count = sect_count - (reserved + fat_size + dir_size);
cluster_count /= vs->sectors_per_cluster;
- dbg("cluster_count 0x%x", cluster_count);
+ info("cluster_count 0x%x\n", cluster_count);
/* must be FAT32 */
if (!fat_length && fat32_length)
/* 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);
+ dbg("root dir start 0x%" PRIx64 "\n", root_start);
root_dir_entries = le16_to_cpu(vs->dir_entries);
- dbg("expected entries 0x%x", root_dir_entries);
+ dbg("expected entries 0x%x\n", root_dir_entries);
buf_size = root_dir_entries * sizeof(struct vfat_dir_entry);
buf = volume_id_get_buffer(id, off + root_start, buf_size);
dir = (struct vfat_dir_entry*) buf;
- label = get_attr_volume_id(dir, root_dir_entries);
+ fnlen = get_fat_attr_volume_id(filename, sizeof(filename), dir, root_dir_entries);
vs = (struct vfat_super_block *) 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);
+ if (fnlen > 0 && memcmp(filename, "NO NAME ", 11) != 0) {
+ volume_id_set_label_raw(id, filename, fnlen);
+ volume_id_set_label_string(id, filename, fnlen);
} 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);
goto found;
fat32:
+ info("looking for FAT32\n");
/* FAT32 should have a valid signature in the fsinfo block */
fsinfo_sect = le16_to_cpu(vs->type.fat32.fsinfo_sector);
buf = volume_id_get_buffer(id, off + (fsinfo_sect * sector_size), 0x200);
if (buf == NULL)
return -1;
fsinfo = (struct fat32_fsinfo *) buf;
+ info("signature1: 0x%02x%02x%02x%02x\n",
+ fsinfo->signature1[0], fsinfo->signature1[1],
+ fsinfo->signature1[2], fsinfo->signature1[3]);
+ info("signature2: 0x%02x%02x%02x%02x\n",
+ fsinfo->signature2[0], fsinfo->signature2[1],
+ fsinfo->signature2[2], fsinfo->signature2[3]);
if (memcmp(fsinfo->signature1, "\x52\x52\x61\x41", 4) != 0)
return -1;
if (memcmp(fsinfo->signature2, "\x72\x72\x41\x61", 4) != 0)
return -1 ;
+ info("FAT32 signatures match\n");
vs = (struct vfat_super_block *) volume_id_get_buffer(id, off, 0x200);
if (vs == NULL)
/* 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);
+ dbg("root dir cluster %u\n", root_cluster);
start_data_sect = reserved + fat_size;
next = root_cluster;
uint64_t fat_entry_off;
int count;
- dbg("next cluster %u", next);
+ dbg("next cluster %u\n", 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);
+ dbg("cluster offset 0x%" PRIx64 "\n", next_off);
/* get cluster */
buf = volume_id_get_buffer(id, off + next_off, buf_size);
dir = (struct vfat_dir_entry*) buf;
count = buf_size / sizeof(struct vfat_dir_entry);
- dbg("expected entries 0x%x", count);
+ dbg("expected entries 0x%x\n", count);
- label = get_attr_volume_id(dir, count);
- if (label)
+ fnlen = get_fat_attr_volume_id(filename, sizeof(filename), dir, count);
+ if (fnlen > 0)
break;
/* get FAT entry */
break;
}
if (maxloop == 0)
- dbg("reached maximum follow count of root cluster chain, give up");
+ dbg("reached maximum follow count of root cluster chain, give up\n");
vs = (struct vfat_super_block *) 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);
+ if (fnlen > 0 && memcmp(filename, "NO NAME ", 11) != 0) {
+ volume_id_set_label_raw(id, filename, fnlen);
+ volume_id_set_label_string(id, filename, fnlen);
} 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);
~ianmdlvl / elogind.git / blobdiff