delete vol_id and require util-linux-ng's blkid

[elogind.git] / extras / volume_id / lib / fat.c

diff --git a/extras/volume_id/lib/fat.c b/extras/volume_id/lib/fat.c
index 9d26a987e0a818fd570ce5c96487120452a2f9fa..c0cfed82c008ccfd9d18c3a37f466f45ea7abbcf 100644 (file)
--- a/extras/volume_id/lib/fat.c
+++ b/extras/volume_id/lib/fat.c
@@ -281,10 +281,6 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t off, uint64_t size)
        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;
@@ -305,6 +301,10 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t off, uint64_t size)
        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)
@@ -348,9 +348,9 @@ magic:
        dbg("sect_count 0x%x\n", sect_count);
 
        fat_length = le16_to_cpu(vs->fat_length);
-       dbg("fat_length 0x%x\n", 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\n", fat32_length);
+       info("fat32_length 0x%x\n", fat32_length);
 
        if (fat_length)
                fat_size = fat_length * vs->fats;
@@ -362,7 +362,7 @@ magic:
 
        dir_size = ((dir_entries * sizeof(struct vfat_dir_entry)) +
                        (sector_size-1)) / sector_size;
-       dbg("dir_size 0x%x\n", 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;
@@ -411,7 +411,11 @@ magic:
 
 fat32:
        info("looking for FAT32\n");
-       /* FAT32 should have a valid signature in the fsinfo block */
+       /*
+        * FAT32 should have a valid signature in the fsinfo block,
+        * but also allow all bytes set to '\0', because some volumes
+        * do not set the signature at all.
+        */
        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)
@@ -423,11 +427,13 @@ fat32:
        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)
+       if (memcmp(fsinfo->signature1, "\x52\x52\x61\x41", 4) != 0 &&
+           memcmp(fsinfo->signature1, "\x00\x00\x00\x00", 4) != 0)
                return -1;
-       if (memcmp(fsinfo->signature2, "\x72\x72\x41\x61", 4) != 0)
+       if (memcmp(fsinfo->signature2, "\x72\x72\x41\x61", 4) != 0 &&
+           memcmp(fsinfo->signature2, "\x00\x00\x00\x00", 4) != 0)
                return -1 ;
-       info("FAT32 signatures match\n");
+       info("FAT32 signatures ok\n");
 
        vs = (struct vfat_super_block *) volume_id_get_buffer(id, off, 0x200);
        if (vs == NULL)
@@ -497,6 +503,7 @@ fat32:
 found:
        volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
        id->type = "vfat";
-
+       /* we think this is fat, but we make sure no other signatures are found */
+       id->force_unique_result = 1;
        return 0;
 }