am f9e23395: Merge "fs_mgr: Support filesystem labels in fstab"
* commit 'f9e2339553f70aebdd170e96ab9332b28c3851b4':
fs_mgr: Support filesystem labels in fstab
diff --git a/fs_mgr/fs_mgr.c b/fs_mgr/fs_mgr.c
index ad02922..bd371e2 100644
--- a/fs_mgr/fs_mgr.c
+++ b/fs_mgr/fs_mgr.c
@@ -28,6 +28,9 @@
#include <libgen.h>
#include <time.h>
#include <sys/swap.h>
+#include <dirent.h>
+#include <ext4.h>
+#include <ext4_sb.h>
#include <linux/loop.h>
#include <private/android_filesystem_config.h>
@@ -335,6 +338,83 @@
return 0;
}
+static int translate_ext_labels(struct fstab_rec *rec)
+{
+ DIR *blockdir = NULL;
+ struct dirent *ent;
+ char *label;
+ size_t label_len;
+ int ret = -1;
+
+ if (strncmp(rec->blk_device, "LABEL=", 6))
+ return 0;
+
+ label = rec->blk_device + 6;
+ label_len = strlen(label);
+
+ if (label_len > 16) {
+ ERROR("FS label is longer than allowed by filesystem\n");
+ goto out;
+ }
+
+
+ blockdir = opendir("/dev/block");
+ if (!blockdir) {
+ ERROR("couldn't open /dev/block\n");
+ goto out;
+ }
+
+ while ((ent = readdir(blockdir))) {
+ int fd;
+ char super_buf[1024];
+ struct ext4_super_block *sb;
+
+ if (!ent->d_type == DT_BLK)
+ continue;
+
+ fd = openat(dirfd(blockdir), ent->d_name, O_RDONLY);
+ if (fd < 0) {
+ ERROR("Cannot open block device /dev/block/%s\n", ent->d_name);
+ goto out;
+ }
+
+ if (TEMP_FAILURE_RETRY(lseek(fd, 1024, SEEK_SET)) < 0 ||
+ TEMP_FAILURE_RETRY(read(fd, super_buf, 1024)) != 1024) {
+ /* Probably a loopback device or something else without a readable
+ * superblock.
+ */
+ close(fd);
+ continue;
+ }
+
+ sb = (struct ext4_super_block *)super_buf;
+ if (sb->s_magic != EXT4_SUPER_MAGIC) {
+ INFO("/dev/block/%s not ext{234}\n", ent->d_name);
+ continue;
+ }
+
+ if (!strncmp(label, sb->s_volume_name, label_len)) {
+ char *new_blk_device;
+
+ if (asprintf(&new_blk_device, "/dev/block/%s", ent->d_name) < 0) {
+ ERROR("Could not allocate block device string\n");
+ goto out;
+ }
+
+ INFO("resolved label %s to %s\n", rec->blk_device, new_blk_device);
+
+ free(rec->blk_device);
+ rec->blk_device = new_blk_device;
+ ret = 0;
+ break;
+ }
+ }
+
+out:
+ closedir(blockdir);
+ return ret;
+}
+
/* When multiple fstab records share the same mount_point, it will
* try to mount each one in turn, and ignore any duplicates after a
* first successful mount.
@@ -366,6 +446,17 @@
continue;
}
+ /* Translate LABEL= file system labels into block devices */
+ if (!strcmp(fstab->recs[i].fs_type, "ext2") ||
+ !strcmp(fstab->recs[i].fs_type, "ext3") ||
+ !strcmp(fstab->recs[i].fs_type, "ext4")) {
+ int tret = translate_ext_labels(&fstab->recs[i]);
+ if (tret < 0) {
+ ERROR("Could not translate label to block device\n");
+ continue;
+ }
+ }
+
if (fstab->recs[i].fs_mgr_flags & MF_WAIT) {
wait_for_file(fstab->recs[i].blk_device, WAIT_TIMEOUT);
}