From 2f9e93973a3d8f90950c605a936ac362be78ed4c Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Mon, 18 Jan 2010 23:58:46 +0100 Subject: [PATCH] libblkid: call read() per FAT root dir entry Signed-off-by: Karel Zak --- shlibs/blkid/src/superblocks/vfat.c | 50 ++++++++++++++++------------- 1 file changed, 27 insertions(+), 23 deletions(-) diff --git a/shlibs/blkid/src/superblocks/vfat.c b/shlibs/blkid/src/superblocks/vfat.c index 8ea6b087..1662f131 100644 --- 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) + -- 2.39.5