[U-Boot] [PATCH] fs: make it possible to read the filesystem UUID

Christian Gmeiner christian.gmeiner at gmail.com
Mon Nov 3 11:47:25 CET 2014


Hi Simon,

2014-11-01 16:13 GMT+01:00 Simon Glass <sjg at chromium.org>:
> Hi Christian,
>
> On 31 October 2014 09:08, Christian Gmeiner <christian.gmeiner at gmail.com> wrote:
>> 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.
>>
>> 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>
>
> If this is version 2 you should have a change list. You can use patman
> (tools/patman/patman) to automate this.

Yes.. the first version was the RFC. I really need to look into
patman. Normally I do
these things per hand.

>
>> ---
>>  README           |  1 +
>>  common/Makefile  |  1 +
>>  fs/ext4/ext4fs.c | 15 +++++++++++++++
>>  fs/fs.c          | 39 +++++++++++++++++++++++++++++++++++++++
>>  include/ext4fs.h |  1 +
>>  include/fs.h     |  2 ++
>>  6 files changed, 59 insertions(+)
>>
>> 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/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
>> index cbdc220..61b6dc2 100644
>> --- a/fs/ext4/ext4fs.c
>> +++ b/fs/ext4/ext4fs.c
>> @@ -187,6 +187,21 @@ int ext4fs_size(const char *filename)
>>         return ext4fs_open(filename);
>>  }
>>
>> +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;
>> +}
>> +
>>  int ext4fs_read(char *buf, unsigned len)
>>  {
>>         if (ext4fs_root == NULL || ext4fs_file == NULL)
>> diff --git a/fs/fs.c b/fs/fs.c
>> index dd680f3..492d8b1 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>
>> @@ -86,6 +87,7 @@ 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[] = {
>> @@ -113,6 +115,7 @@ static struct fstype_info fstypes[] = {
>>                 .size = ext4fs_size,
>>                 .read = ext4_read_file,
>>                 .write = fs_write_unsupported,
>> +               .uuid = ext4fs_uuid,
>>         },
>>  #endif
>>  #ifdef CONFIG_SANDBOX
>> @@ -206,6 +209,17 @@ 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);
>> +       int ret = -ENOSYS;
>> +
>> +       if (info->uuid)
>> +               ret = info->uuid(uuid_str);
>> +
>> +       return ret;
>> +}
>> +
>>  int fs_ls(const char *dirname)
>>  {
>>         int ret;
>> @@ -443,3 +457,28 @@ 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 ret;
>
> Here you should return CMD_RET_SUCCESS or CMD_RET_FAILURE. You should
> not return raw errors since they are not the same thing.

Okay. will be fixed in next version of the patch.

>
>> +
>> +       if (argc == 4)
>> +               setenv(argv[3], uuid);
>> +       else
>> +               printf("%s\n", uuid);
>> +
>> +       return 0;
>> +}
>> diff --git a/include/ext4fs.h b/include/ext4fs.h
>> index 6c419f3..19816de 100644
>> --- a/include/ext4fs.h
>> +++ b/include/ext4fs.h
>> @@ -137,6 +137,7 @@ void ext4fs_reinit_global(void);
>>  int ext4fs_ls(const char *dirname);
>>  int ext4fs_exists(const char *filename);
>>  int ext4fs_size(const char *filename);
>> +int ext4fs_uuid(char *uuid_str);
>>  void ext4fs_free_node(struct ext2fs_node *node, struct ext2fs_node *currroot);
>>  int ext4fs_devread(lbaint_t sector, int byte_offset, int byte_len, char *buf);
>>  void ext4fs_set_blk_dev(block_dev_desc_t *rbdd, disk_partition_t *info);
>> diff --git a/include/fs.h b/include/fs.h
>> index 06a45f2..41082b3 100644
>> --- a/include/fs.h
>> +++ b/include/fs.h
>> @@ -92,5 +92,7 @@ int file_exists(const char *dev_type, const char *dev_part, const char *file,
>>                 int fstype);
>>  int do_save(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
>>                 int fstype);
>> +int do_fs_uuid(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
>> +               int fstype);
>
> Can you please add a function comment for this?

Yes I will add one  - directly here in the .h file?

>
>>
>>  #endif /* _FS_H */
>> --
>> 1.9.3
>>
>
> Regards,
> Simon

Greets
--
Christian Gmeiner, MSc

https://soundcloud.com/christian-gmeiner


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