chiark / gitweb /
volume_id: check ext fs for valid blocksize, cause magic is only 2 bytes
authorKay Sievers <kay@pim>
Sun, 23 Oct 2005 15:41:55 +0000 (17:41 +0200)
committerKay Sievers <kay@pim>
Sun, 23 Oct 2005 15:41:55 +0000 (17:41 +0200)
Signed-off-by: Kay Sievers <kay.sievers@suse.de>
extras/volume_id/volume_id/ext.c
extras/volume_id/volume_id/util.h

index df2ebb6..7080f1d 100644 (file)
 #include "ext.h"
 
 struct ext2_super_block {
-       uint32_t        inodes_count;
-       uint32_t        blocks_count;
-       uint32_t        r_blocks_count;
-       uint32_t        free_blocks_count;
-       uint32_t        free_inodes_count;
-       uint32_t        first_data_block;
-       uint32_t        log_block_size;
-       uint32_t        dummy3[7];
-       uint8_t magic[2];
-       uint16_t        state;
-       uint32_t        dummy5[8];
-       uint32_t        feature_compat;
-       uint32_t        feature_incompat;
-       uint32_t        feature_ro_compat;
-       uint8_t uuid[16];
-       uint8_t volume_name[16];
+       uint32_t        s_inodes_count;
+       uint32_t        s_blocks_count;
+       uint32_t        s_r_blocks_count;
+       uint32_t        s_free_blocks_count;
+       uint32_t        s_free_inodes_count;
+       uint32_t        s_first_data_block;
+       uint32_t        s_log_block_size;
+       uint32_t        s_log_frag_size;
+       uint32_t        s_blocks_per_group;
+       uint32_t        s_frags_per_group;
+       uint32_t        s_inodes_per_group;
+       uint32_t        s_mtime;
+       uint32_t        s_wtime;
+       uint16_t        s_mnt_count;
+       uint16_t        s_max_mnt_count;
+       uint16_t        s_magic;
+       uint16_t        s_state;
+       uint16_t        s_errors;
+       uint16_t        s_minor_rev_level;
+       uint32_t        s_lastcheck;
+       uint32_t        s_checkinterval;
+       uint32_t        s_creator_os;
+       uint32_t        s_rev_level;
+       uint16_t        s_def_resuid;
+       uint16_t        s_def_resgid;
+       uint32_t        s_first_ino;
+       uint16_t        s_inode_size;
+       uint16_t        s_block_group_nr;
+       uint32_t        s_feature_compat;
+       uint32_t        s_feature_incompat;
+       uint32_t        s_feature_ro_compat;
+       uint8_t         s_uuid[16];
+       uint8_t         s_volume_name[16];
 } __attribute__((__packed__));
 
+#define EXT_SUPER_MAGIC                                0xEF53
 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL                0x00000004
 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV      0x00000008
 #define EXT_SUPERBLOCK_OFFSET                  0x400
 
+#define EXT3_MIN_BLOCK_SIZE                    0x400
+#define EXT3_MAX_BLOCK_SIZE                    0x1000
+
 int volume_id_probe_ext(struct volume_id *id, uint64_t off)
 {
        struct ext2_super_block *es;
+       size_t bsize;
 
        dbg("probing at offset 0x%llx", (unsigned long long) off);
 
@@ -61,16 +83,32 @@ int volume_id_probe_ext(struct volume_id *id, uint64_t off)
        if (es == NULL)
                return -1;
 
-       if (es->magic[0] != 0123 ||
-           es->magic[1] != 0357)
+       if (es->s_magic != cpu_to_le16(EXT_SUPER_MAGIC))
                return -1;
 
-       volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
-       volume_id_set_label_raw(id, es->volume_name, 16);
-       volume_id_set_label_string(id, es->volume_name, 16);
-       volume_id_set_uuid(id, es->uuid, UUID_DCE);
+       bsize = 0x200 << le32_to_cpu(es->s_log_block_size);
+       dbg("ext blocksize 0x%zx", bsize);
+       if (bsize < EXT3_MIN_BLOCK_SIZE || bsize > EXT3_MAX_BLOCK_SIZE) {
+               dbg("invalid ext blocksize");
+               return -1;
+       }
 
-       if ((le32_to_cpu(es->feature_compat) & EXT3_FEATURE_COMPAT_HAS_JOURNAL) != 0)
+       volume_id_set_label_raw(id, es->s_volume_name, 16);
+       volume_id_set_label_string(id, es->s_volume_name, 16);
+       volume_id_set_uuid(id, es->s_uuid, UUID_DCE);
+       snprintf(id->type_version, sizeof(id->type_version)-1,
+                "%u.%u", es->s_rev_level, es->s_minor_rev_level);
+
+       /* check for external journal device */
+       if ((le32_to_cpu(es->s_feature_incompat) & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) != 0) {
+               volume_id_set_usage(id, VOLUME_ID_OTHER);
+               id->type = "jbd";
+               return 0;
+       }
+
+       /* check for ext2 / ext3 */
+       volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
+       if ((le32_to_cpu(es->s_feature_compat) & EXT3_FEATURE_COMPAT_HAS_JOURNAL) != 0)
                id->type = "ext3";
        else
                id->type = "ext2";
index afaa0b7..6e16491 100644 (file)
@@ -51,6 +51,7 @@
 #define le64_to_cpu(x) (x)
 #define be16_to_cpu(x) bswap16(x)
 #define be32_to_cpu(x) bswap32(x)
+#define cpu_to_le16(x) (x)
 #define cpu_to_le32(x) (x)
 #define cpu_to_be32(x) bswap32(x)
 #elif (__BYTE_ORDER == __BIG_ENDIAN)
@@ -59,6 +60,7 @@
 #define le64_to_cpu(x) bswap64(x)
 #define be16_to_cpu(x) (x)
 #define be32_to_cpu(x) (x)
+#define cpu_to_le16(x) bswap16(x)
 #define cpu_to_le32(x) bswap32(x)
 #define cpu_to_be32(x) (x)
 #endif