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

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@gmail.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 7b5538e..53b84a6 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..19757d2 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; +#endif + + return -ENOSYS; +} 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 */