GPT: add accessor function for disk GUID

In order to read the GPT, modify the partition name strings, and then
write out a new GPT, the disk GUID is needed.  While there is an
existing accessor for the partition UUIDs, there is none yet for the
disk GUID.

Changes since v6: none.

Signed-off-by: Alison Chaiken <alison@peloton-tech.com>
This commit is contained in:
Alison Chaiken 2017-06-25 16:43:23 -07:00 committed by Tom Rini
parent e6faf21f25
commit 73d6d18b71
4 changed files with 74 additions and 1 deletions

View File

@ -398,6 +398,23 @@ static int gpt_verify(struct blk_desc *blk_dev_desc, const char *str_part)
return ret;
}
static int do_disk_guid(struct blk_desc *dev_desc, char * const namestr)
{
int ret;
char disk_guid[UUID_STR_LEN + 1];
ret = get_disk_guid(dev_desc, disk_guid);
if (ret < 0)
return CMD_RET_FAILURE;
if (namestr)
setenv(namestr, disk_guid);
else
printf("%s\n", disk_guid);
return ret;
}
/**
* do_gpt(): Perform GPT operations
*
@ -436,6 +453,8 @@ static int do_gpt(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
} else if ((strcmp(argv[1], "verify") == 0)) {
ret = gpt_verify(blk_dev_desc, argv[4]);
printf("Verify GPT: ");
} else if (strcmp(argv[1], "guid") == 0) {
ret = do_disk_guid(blk_dev_desc, argv[4]);
} else {
return CMD_RET_USAGE;
}
@ -458,4 +477,11 @@ U_BOOT_CMD(gpt, CONFIG_SYS_MAXARGS, 1, do_gpt,
" Example usage:\n"
" gpt write mmc 0 $partitions\n"
" gpt verify mmc 0 $partitions\n"
" guid <interface> <dev>\n"
" - print disk GUID\n"
" guid <interface> <dev> <varname>\n"
" - set environment variable to disk GUID\n"
" Example usage:\n"
" gpt guid mmc 0\n"
" gpt guid mmc 0 varname\n"
);

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@ -178,6 +178,37 @@ static void prepare_backup_gpt_header(gpt_header *gpt_h)
* Public Functions (include/part.h)
*/
/*
* UUID is displayed as 32 hexadecimal digits, in 5 groups,
* separated by hyphens, in the form 8-4-4-4-12 for a total of 36 characters
*/
int get_disk_guid(struct blk_desc * dev_desc, char *guid)
{
ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
gpt_entry *gpt_pte = NULL;
unsigned char *guid_bin;
/* This function validates AND fills in the GPT header and PTE */
if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
gpt_head, &gpt_pte) != 1) {
printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
if (is_gpt_valid(dev_desc, dev_desc->lba - 1,
gpt_head, &gpt_pte) != 1) {
printf("%s: *** ERROR: Invalid Backup GPT ***\n",
__func__);
return -EINVAL;
} else {
printf("%s: *** Using Backup GPT ***\n",
__func__);
}
}
guid_bin = gpt_head->disk_guid.b;
uuid_bin_to_str(guid_bin, guid, UUID_STR_FORMAT_GUID);
return 0;
}
void part_print_efi(struct blk_desc *dev_desc)
{
ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);

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@ -171,7 +171,8 @@ To restore GUID partition table one needs to:
The fields 'uuid' and 'uuid_disk' are optional if CONFIG_RANDOM_UUID is
enabled. A random uuid will be used if omitted or they point to an empty/
non-existent environment variable. The environment variable will be set to
the generated UUID.
the generated UUID. The 'gpt guid' command reads the current value of the
uuid_disk from the GPT.
The field 'bootable' is optional, it is used to mark the GPT partition
bootable (set attribute flags "Legacy BIOS bootable").

View File

@ -372,6 +372,21 @@ int gpt_verify_headers(struct blk_desc *dev_desc, gpt_header *gpt_head,
int gpt_verify_partitions(struct blk_desc *dev_desc,
disk_partition_t *partitions, int parts,
gpt_header *gpt_head, gpt_entry **gpt_pte);
/**
* get_disk_guid() - Function to read the GUID string from a device's GPT
*
* This function reads the GUID string from a block device whose descriptor
* is provided.
*
* @param dev_desc - block device descriptor
* @param guid - pre-allocated string in which to return the GUID
*
* @return - '0' on success, otherwise error
*/
int get_disk_guid(struct blk_desc *dev_desc, char *guid);
#endif
#if CONFIG_IS_ENABLED(DOS_PARTITION)