blkid: add version and probe FSInfo

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libs/blkid/src/probers/vfat.c b/libs/blkid/src/probers/vfat.c
index c277afe8138753d35fc68ceafd8b32eacb28796c..e3b9bb30e2da56136db4b954e730b487d6e9c653 100644 (file)
--- a/libs/blkid/src/probers/vfat.c
+++ b/libs/blkid/src/probers/vfat.c
@@ -45,7 +45,7 @@ struct vfat_super_block {
 /* 28*/        uint16_t        vs_flags;
 /* 2a*/        uint8_t         vs_version[2];
 /* 2c*/        uint32_t        vs_root_cluster;
-/* 30*/        uint16_t        vs_insfo_sector;
+/* 30*/        uint16_t        vs_fsinfo_sector;
 /* 32*/        uint16_t        vs_backup_boot;
 /* 34*/        uint16_t        vs_reserved2[6];
 /* 40*/        unsigned char   vs_unknown[3];
@@ -94,6 +94,15 @@ struct vfat_dir_entry {
        uint32_t        size;
 };
 
+struct fat32_fsinfo {
+       uint8_t signature1[4];
+       uint32_t reserved1[120];
+       uint8_t signature2[4];
+       uint32_t free_clusters;
+       uint32_t next_cluster;
+       uint32_t reserved2[4];
+};
+
 /* maximum number of clusters */
 #define FAT12_MAX 0xFF4
 #define FAT16_MAX 0xFFF4
@@ -188,6 +197,7 @@ static int probe_vfat(blkid_probe pr, const struct blkid_idmag *mag)
        uint16_t sector_size, dir_entries, reserved;
        uint32_t sect_count, fat_size, dir_size, cluster_count, fat_length;
        uint32_t buf_size, start_data_sect, next, root_start, root_dir_entries;
+       const char *version = NULL;
 
 
        /* non-standard magic strings */
@@ -251,12 +261,21 @@ static int probe_vfat(blkid_probe pr, const struct blkid_idmag *mag)
 
                blkid_probe_set_value(pr, "SEC_TYPE", (unsigned char *) "msdos",
                               sizeof("msdos"));
+
+               if (cluster_count < FAT12_MAX)
+                       version = "FAT12";
+               else if (cluster_count < FAT16_MAX)
+                       version = "FAT16";
        } else {
                unsigned char *buf;
+               uint16_t fsinfo_sect;
+
                /* Search the FAT32 root dir for the label attribute */
                buf_size = vs->vs_cluster_size * sector_size;
                start_data_sect = reserved + fat_size;
 
+               version = "FAT32";
+
                next = le32_to_cpu(vs->vs_root_cluster);
                while (next && --maxloop) {
                        uint32_t next_sect_off;
@@ -292,6 +311,30 @@ static int probe_vfat(blkid_probe pr, const struct blkid_idmag *mag)
                if (!vol_label || !memcmp(vol_label, no_name, 11))
                        vol_label = vs->vs_label;
                vol_serno = vs->vs_serno;
+
+               /*
+                * 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->vs_fsinfo_sector);
+               if (fsinfo_sect) {
+                       struct fat32_fsinfo *fsinfo;
+
+                       buf = blkid_probe_get_buffer(pr,
+                                       fsinfo_sect * sector_size,
+                                       sizeof(struct fat32_fsinfo));
+                       if (buf == NULL)
+                               return -1;
+
+                       fsinfo = (struct fat32_fsinfo *) buf;
+                       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 &&
+                           memcmp(fsinfo->signature2, "\x00\x00\x00\x00", 4) != 0)
+                               return -1;
+               }
        }
 
        if (vol_label && memcmp(vol_label, no_name, 11))
@@ -301,6 +344,9 @@ static int probe_vfat(blkid_probe pr, const struct blkid_idmag *mag)
        blkid_probe_sprintf_uuid(pr, vol_serno, 4, "%02X%02X-%02X%02X",
                vol_serno[3], vol_serno[2], vol_serno[1], vol_serno[0]);
 
+       if (version)
+               blkid_probe_set_version(pr, version);
+
        return 0;
 }