libblkid: call read() per FAT root dir entry

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

diff --git a/shlibs/blkid/src/superblocks/vfat.c b/shlibs/blkid/src/superblocks/vfat.c
index 8ea6b08751d8490877740bcf609c8440119ce979..1662f1319ce7b2696be799a6c73b1be8cd36b422 100644 (file)
--- a/shlibs/blkid/src/superblocks/vfat.c
+++ b/shlibs/blkid/src/superblocks/vfat.c
@@ -111,22 +111,29 @@ struct fat32_fsinfo {
 
 static const char *no_name = "NO NAME    ";
 
-static unsigned char *search_fat_label(struct vfat_dir_entry *dir, int count)
+static unsigned char *search_fat_label(blkid_probe pr,
+                               uint32_t offset, uint32_t entries)
 {
+       struct vfat_dir_entry *dir;
        int i;
 
-       for (i = 0; i < count; i++) {
-               if (dir[i].name[0] == 0x00)
+       for (i = 0; i < entries; i++) {
+
+               dir = (struct vfat_dir_entry *)
+                               blkid_probe_get_extra_buffer(pr,
+                                       offset + (i * sizeof(struct vfat_dir_entry)),
+                                       sizeof(struct vfat_dir_entry));
+               if (dir->name[0] == 0x00)
                        break;
 
-               if ((dir[i].name[0] == FAT_ENTRY_FREE) ||
-                   (dir[i].cluster_high != 0 || dir[i].cluster_low != 0) ||
-                   ((dir[i].attr & FAT_ATTR_MASK) == FAT_ATTR_LONG_NAME))
+               if ((dir->name[0] == FAT_ENTRY_FREE) ||
+                   (dir->cluster_high != 0 || dir->cluster_low != 0) ||
+                   ((dir->attr & FAT_ATTR_MASK) == FAT_ATTR_LONG_NAME))
                        continue;
 
-               if ((dir[i].attr & (FAT_ATTR_VOLUME_ID | FAT_ATTR_DIR)) ==
+               if ((dir->attr & (FAT_ATTR_VOLUME_ID | FAT_ATTR_DIR)) ==
                    FAT_ATTR_VOLUME_ID) {
-                       return dir[i].name;
+                       return dir->name;
                }
        }
        return 0;
@@ -188,9 +195,8 @@ static int probe_vfat(blkid_probe pr, const struct blkid_idmag *mag)
 {
        struct vfat_super_block *vs;
        struct msdos_super_block *ms;
-       struct vfat_dir_entry *dir;
        const unsigned char *vol_label = 0, *tmp;
-       unsigned char   *vol_serno;
+       unsigned char *vol_serno, vol_label_buf[11];
        int maxloop = 100;
        uint16_t sector_size, dir_entries, reserved;
        uint32_t sect_count, fat_size, dir_size, cluster_count, fat_length;
@@ -198,6 +204,7 @@ static int probe_vfat(blkid_probe pr, const struct blkid_idmag *mag)
        const char *version = NULL;
 
 
+
        /* non-standard magic strings */
        if (mag->len <= 2 && probe_fat_nomagic(pr, mag) != 0)
                return 1;
@@ -247,12 +254,11 @@ static int probe_vfat(blkid_probe pr, const struct blkid_idmag *mag)
                root_dir_entries = vs->vs_dir_entries[0] +
                        (vs->vs_dir_entries[1] << 8);
 
-               buf_size = root_dir_entries * sizeof(struct vfat_dir_entry);
-
-               dir = (struct vfat_dir_entry *)
-                       blkid_probe_get_extra_buffer(pr, root_start, buf_size);
-               if (dir)
-                       vol_label = search_fat_label(dir, root_dir_entries);
+               vol_label = search_fat_label(pr, root_start, root_dir_entries);
+               if (vol_label) {
+                       memcpy(vol_label_buf, vol_label, 11);
+                       vol_label = vol_label_buf;
+               }
 
                if (!vol_label || !memcmp(vol_label, no_name, 11))
                        vol_label = ms->ms_label;
@@ -285,16 +291,14 @@ static int probe_vfat(blkid_probe pr, const struct blkid_idmag *mag)
                        next_off = (start_data_sect + next_sect_off) *
                                sector_size;
 
-                       dir = (struct vfat_dir_entry *)
-                               blkid_probe_get_extra_buffer(pr, next_off, buf_size);
-                       if (dir == NULL)
-                               break;
-
                        count = buf_size / sizeof(struct vfat_dir_entry);
 
-                       vol_label = search_fat_label(dir, count);
-                       if (vol_label)
+                       vol_label = search_fat_label(pr, next_off, count);
+                       if (vol_label) {
+                               memcpy(vol_label_buf, vol_label, 11);
+                               vol_label = vol_label_buf;
                                break;
+                       }
 
                        /* get FAT entry */
                        fat_entry_off = (reserved * sector_size) +