Enhanced Read-Only File System (EROFS) has been included in Linux
kernel, many Linux distributions, buildroot and Android AOSP for
a while. Plus, nowadays, it's known that EROFS has been commercially
used by several Android vendors for their system partitions.
util-linux in busybox can also detect it recently.
This patch adds support for detecting EROFS filesystem to libblkid.
Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxx>
---
libblkid/src/Makemodule.am | 1 +
libblkid/src/superblocks/erofs.c | 73 ++++++++++++++++++++++++++
libblkid/src/superblocks/superblocks.c | 3 +-
libblkid/src/superblocks/superblocks.h | 1 +
4 files changed, 77 insertions(+), 1 deletion(-)
create mode 100644 libblkid/src/superblocks/erofs.c
diff --git a/libblkid/src/Makemodule.am b/libblkid/src/Makemodule.am
index 1aa6dfcef..16a0a2826 100644
--- a/libblkid/src/Makemodule.am
+++ b/libblkid/src/Makemodule.am
@@ -101,6 +101,7 @@ libblkid_la_SOURCES = \
libblkid/src/superblocks/xfs.c \
libblkid/src/superblocks/zfs.c \
libblkid/src/superblocks/zonefs.c \
+ libblkid/src/superblocks/erofs.c \
\
libblkid/src/topology/topology.c \
libblkid/src/topology/topology.h
diff --git a/libblkid/src/superblocks/erofs.c b/libblkid/src/superblocks/erofs.c
new file mode 100644
index 000000000..0e7b4223d
--- /dev/null
+++ b/libblkid/src/superblocks/erofs.c
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2020 Gao Xiang
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License
+ */
+#include <stddef.h>
+#include <string.h>
+
+#include "superblocks.h"
+
+#define EROFS_SUPER_OFFSET 1024
+#define EROFS_SB_KBOFF (EROFS_SUPER_OFFSET >> 10)
+
+#define EROFS_SUPER_MAGIC_V1 "\xe2\xe1\xf5\xe0"
+#define EROFS_MAGIC_OFF 0
+
+/* All in little-endian */
+struct erofs_super_block {
+ uint32_t magic;
+ uint32_t checksum;
+ uint32_t feature_compat;
+ uint8_t blkszbits;
+ uint8_t reserved;
+
+ uint16_t root_nid;
+ uint64_t inos;
+
+ uint64_t build_time;
+ uint32_t build_time_nsec;
+ uint32_t blocks;
+ uint32_t meta_blkaddr;
+ uint32_t xattr_blkaddr;
+ uint8_t uuid[16];
+ uint8_t volume_name[16];
+ uint32_t feature_incompat;
+ uint8_t reserved2[44];
+};
+
+static int probe_erofs(blkid_probe pr, const struct blkid_idmag *mag)
+{
+ struct erofs_super_block *sb;
+
+ sb = blkid_probe_get_sb(pr, mag, struct erofs_super_block);
+ if (!sb)
+ return errno ? -errno : BLKID_PROBE_NONE;
+
+ if (sb->volume_name[0])
+ blkid_probe_set_label(pr, (unsigned char *)sb->volume_name,
+ sizeof(sb->volume_name));
+
+ blkid_probe_set_uuid(pr, sb->uuid);
+
+ if (sb->blkszbits < 32)
+ blkid_probe_set_block_size(pr, 1U << sb->blkszbits);
+ return BLKID_PROBE_OK;
+}
+
+const struct blkid_idinfo erofs_idinfo =
+{
+ .name = "erofs",
+ .usage = BLKID_USAGE_FILESYSTEM,
+ .probefunc = probe_erofs,
+ .magics =
+ {
+ {
+ .magic = EROFS_SUPER_MAGIC_V1,
+ .len = 4,
+ .kboff = EROFS_SB_KBOFF,
+ .sboff = EROFS_MAGIC_OFF,
+ }, { NULL }
+ }
+};
diff --git a/libblkid/src/superblocks/superblocks.c b/libblkid/src/superblocks/superblocks.c
index 7b0f5eed0..f21365538 100644
--- a/libblkid/src/superblocks/superblocks.c
+++ b/libblkid/src/superblocks/superblocks.c
@@ -168,7 +168,8 @@ static const struct blkid_idinfo *idinfos[] =
&f2fs_idinfo,
&mpool_idinfo,
&apfs_idinfo,
- &zonefs_idinfo
+ &zonefs_idinfo,
+ &erofs_idinfo
};
/*
diff --git a/libblkid/src/superblocks/superblocks.h b/libblkid/src/superblocks/superblocks.h
index 5ebe6bc43..9c489c438 100644
--- a/libblkid/src/superblocks/superblocks.h
+++ b/libblkid/src/superblocks/superblocks.h
@@ -85,6 +85,7 @@ extern const struct blkid_idinfo stratis_idinfo;
extern const struct blkid_idinfo bitlocker_idinfo;
extern const struct blkid_idinfo apfs_idinfo;
extern const struct blkid_idinfo zonefs_idinfo;
+extern const struct blkid_idinfo erofs_idinfo;
/*
* superblock functions
--
2.18.4
