[U-Boot] [PATCH v3] fs: make it possible to read the filesystem UUID
Christian Gmeiner
christian.gmeiner at gmail.com
Wed Nov 12 14:35:04 CET 2014
Some filesystems have a UUID stored in its superblock. To
allow using root=UUID=... for the kernel command line we
need a way to read-out the filesystem UUID.
changes rfc -> v1:
- make the environment variable an option parameter. If not
given, the UUID is printed out. If given, it is stored in the env
variable.
- corrected typos
- return error codes
changes v1 -> v2:
- fix return code of do_fs_uuid(..)
- document do_fs_uuid(..)
- implement fs_uuid_unsuported(..) be more consistent with the
way other optional functionality works
changes v2 -> v3:
- change ext4fs_uuid(..) to make use of #if .. #else .. #endif
construct to get rid of unreachable code
Hit any key to stop autoboot: 0
=> fsuuid
fsuuid - Look up a filesystem UUID
Usage:
fsuuid <interface> <dev>:<part>
- print filesystem UUID
fsuuid <interface> <dev>:<part> <varname>
- set environment variable to filesystem UUID
=> fsuuid mmc 0:1
d9f9fc05-45ae-4a36-a616-fccce0e4f887
=> fsuuid mmc 0:2
eb3db83c-7b28-499f-95ce-9e0bb21cda81
=> fsuuid mmc 0:1 uuid1
=> fsuuid mmc 0:2 uuid2
=> printenv uuid1
uuid1=d9f9fc05-45ae-4a36-a616-fccce0e4f887
=> printenv uuid2
uuid2=eb3db83c-7b28-499f-95ce-9e0bb21cda81
=>
Signed-off-by: Christian Gmeiner <christian.gmeiner at gmail.com>
Acked-by: Stephen Warren <swarren at nvidia.com>
---
README | 1 +
common/Makefile | 1 +
common/cmd_fs_uuid.c | 26 ++++++++++++++++++++++++++
fs/ext4/ext4fs.c | 15 +++++++++++++++
fs/fs.c | 43 +++++++++++++++++++++++++++++++++++++++++++
include/ext4fs.h | 1 +
include/fs.h | 7 +++++++
7 files changed, 94 insertions(+)
create mode 100644 common/cmd_fs_uuid.c
diff --git a/README b/README
index c3a9dfc..b48de5f 100644
--- a/README
+++ b/README
@@ -989,6 +989,7 @@ The following options need to be configured:
CONFIG_CMD_EXT4 * ext4 command support
CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
that work for multiple fs types
+ CONFIG_CMD_FS_UUID * Look up a filesystem UUID
CONFIG_CMD_SAVEENV saveenv
CONFIG_CMD_FDC * Floppy Disk Support
CONFIG_CMD_FAT * FAT command support
diff --git a/common/Makefile b/common/Makefile
index 6cc4de8..508a0b2 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -188,6 +188,7 @@ obj-y += usb.o usb_hub.o
obj-$(CONFIG_USB_STORAGE) += usb_storage.o
endif
obj-$(CONFIG_CMD_FASTBOOT) += cmd_fastboot.o
+obj-$(CONFIG_CMD_FS_UUID) += cmd_fs_uuid.o
obj-$(CONFIG_CMD_USB_MASS_STORAGE) += cmd_usb_mass_storage.o
obj-$(CONFIG_CMD_THOR_DOWNLOAD) += cmd_thordown.o
diff --git a/common/cmd_fs_uuid.c b/common/cmd_fs_uuid.c
new file mode 100644
index 0000000..613f3a4
--- /dev/null
+++ b/common/cmd_fs_uuid.c
@@ -0,0 +1,26 @@
+/*
+ * cmd_fs_uuid.c -- fsuuid command
+ *
+ * Copyright (C) 2014, Bachmann electronic GmbH
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <command.h>
+#include <fs.h>
+
+static int do_fs_uuid_wrapper(cmd_tbl_t *cmdtp, int flag,
+ int argc, char * const argv[])
+{
+ return do_fs_uuid(cmdtp, flag, argc, argv, FS_TYPE_ANY);
+}
+
+U_BOOT_CMD(
+ fsuuid, 4, 1, do_fs_uuid_wrapper,
+ "Look up a filesystem UUID",
+ "<interface> <dev>:<part>\n"
+ " - print filesystem UUID\n"
+ "fsuuid <interface> <dev>:<part> <varname>\n"
+ " - set environment variable to filesystem UUID\n"
+);
diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
index cbdc220..87d5128 100644
--- a/fs/ext4/ext4fs.c
+++ b/fs/ext4/ext4fs.c
@@ -231,3 +231,18 @@ int ext4_read_file(const char *filename, void *buf, int offset, int len)
return len_read;
}
+
+int ext4fs_uuid(char *uuid_str)
+{
+ if (ext4fs_root == NULL)
+ return -1;
+
+#ifdef CONFIG_LIB_UUID
+ uuid_bin_to_str((unsigned char *)ext4fs_root->sblock.unique_id,
+ uuid_str, UUID_STR_FORMAT_STD);
+
+ return 0;
+#else
+ return -ENOSYS;
+#endif
+}
diff --git a/fs/fs.c b/fs/fs.c
index dd680f3..e4ad6bc 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -15,6 +15,7 @@
*/
#include <config.h>
+#include <errno.h>
#include <common.h>
#include <part.h>
#include <ext4fs.h>
@@ -67,6 +68,11 @@ static inline void fs_close_unsupported(void)
{
}
+static inline int fs_uuid_unsupported(char *uuid_str)
+{
+ return -1;
+}
+
struct fstype_info {
int fstype;
/*
@@ -86,6 +92,7 @@ struct fstype_info {
int (*read)(const char *filename, void *buf, int offset, int len);
int (*write)(const char *filename, void *buf, int offset, int len);
void (*close)(void);
+ int (*uuid)(char *uuid_str);
};
static struct fstype_info fstypes[] = {
@@ -100,6 +107,7 @@ static struct fstype_info fstypes[] = {
.size = fat_size,
.read = fat_read_file,
.write = fs_write_unsupported,
+ .uuid = fs_uuid_unsupported,
},
#endif
#ifdef CONFIG_FS_EXT4
@@ -113,6 +121,7 @@ static struct fstype_info fstypes[] = {
.size = ext4fs_size,
.read = ext4_read_file,
.write = fs_write_unsupported,
+ .uuid = ext4fs_uuid,
},
#endif
#ifdef CONFIG_SANDBOX
@@ -126,6 +135,7 @@ static struct fstype_info fstypes[] = {
.size = sandbox_fs_size,
.read = fs_read_sandbox,
.write = fs_write_sandbox,
+ .uuid = fs_uuid_unsupported,
},
#endif
{
@@ -138,6 +148,7 @@ static struct fstype_info fstypes[] = {
.size = fs_size_unsupported,
.read = fs_read_unsupported,
.write = fs_write_unsupported,
+ .uuid = fs_uuid_unsupported,
},
};
@@ -206,6 +217,13 @@ static void fs_close(void)
fs_type = FS_TYPE_ANY;
}
+int fs_uuid(char *uuid_str)
+{
+ struct fstype_info *info = fs_get_info(fs_type);
+
+ return info->uuid(uuid_str);
+}
+
int fs_ls(const char *dirname)
{
int ret;
@@ -443,3 +461,28 @@ int do_save(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
return 0;
}
+
+int do_fs_uuid(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
+ int fstype)
+{
+ int ret;
+ char uuid[37];
+ memset(uuid, 0, sizeof(uuid));
+
+ if (argc < 3 || argc > 4)
+ return CMD_RET_USAGE;
+
+ if (fs_set_blk_dev(argv[1], argv[2], fstype))
+ return 1;
+
+ ret = fs_uuid(uuid);
+ if (ret)
+ return CMD_RET_FAILURE;
+
+ if (argc == 4)
+ setenv(argv[3], uuid);
+ else
+ printf("%s\n", uuid);
+
+ return CMD_RET_SUCCESS;
+}
diff --git a/include/ext4fs.h b/include/ext4fs.h
index 6c419f3..38970e4 100644
--- a/include/ext4fs.h
+++ b/include/ext4fs.h
@@ -145,4 +145,5 @@ int ext4fs_probe(block_dev_desc_t *fs_dev_desc,
disk_partition_t *fs_partition);
int ext4_read_file(const char *filename, void *buf, int offset, int len);
int ext4_read_superblock(char *buffer);
+int ext4fs_uuid(char *uuid_str);
#endif
diff --git a/include/fs.h b/include/fs.h
index 06a45f2..491c60a 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -93,4 +93,11 @@ int file_exists(const char *dev_type, const char *dev_part, const char *file,
int do_save(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
int fstype);
+/*
+ * Determine the UUID of the specified filesystem and print it. Optionally it is
+ * possible to store the UUID directly in env.
+ */
+int do_fs_uuid(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
+ int fstype);
+
#endif /* _FS_H */
--
1.9.3
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