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probe: Support probing for partition UUID with --part-uuid

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Linux supports root=PARTUUID=<partuuid> boot argument, so add
support for probing it. Compared to the fs UUID, the partition
UUID does not change when reformatting a partition.

For now, only disks using a GPT partition table are supported.

Signed-off-by: Jacob Kroon <jacob.kroon@gmail.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Jacob Kroon 2019-05-15 21:04:43 +02:00 committed by Daniel Kiper
parent 26094f5241
commit f2b9083f85
2 changed files with 37 additions and 1 deletions
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4
docs/grub.texi
View file

@ -4771,9 +4771,11 @@ a rest.
@node probe
@subsection probe
@deffn Command probe [@option{--set} var] @option{--driver}|@option{--partmap}|@option{--fs}|@option{--fs-uuid}|@option{--label} device
@deffn Command probe [@option{--set} var] @option{--driver}|@option{--partmap}|@option{--fs}|@option{--fs-uuid}|@option{--label}|@option{--part-uuid} device
Retrieve device information. If option @option{--set} is given, assign result
to variable @var{var}, otherwise print information on the screen.
The option @option{--part-uuid} is currently only implemented for GPT-formatted disks.
@end deffn

34
grub-core/commands/probe.c
View file

@ -24,6 +24,7 @@
#include <grub/device.h>
#include <grub/disk.h>
#include <grub/partition.h>
#include <grub/gpt_partition.h>
#include <grub/net.h>
#include <grub/fs.h>
#include <grub/file.h>
@ -45,6 +46,7 @@ static const struct grub_arg_option options[] =
{"fs", 'f', 0, N_("Determine filesystem type."), 0, 0},
{"fs-uuid", 'u', 0, N_("Determine filesystem UUID."), 0, 0},
{"label", 'l', 0, N_("Determine filesystem label."), 0, 0},
{"part-uuid", 0, 0, N_("Determine partition UUID."), 0, 0},
{0, 0, 0, 0, 0, 0}
};
@ -98,6 +100,38 @@ grub_cmd_probe (grub_extcmd_context_t ctxt, int argc, char **args)
grub_device_close (dev);
return GRUB_ERR_NONE;
}
if (state[6].set)
{
/* AAAABBBB-CCCC-DDDD-EEEE-FFFFFFFFFFFF + null terminator */
char val[37] = "none";
if (dev->disk && dev->disk->partition &&
grub_strcmp(dev->disk->partition->partmap->name, "gpt") == 0)
{
struct grub_gpt_partentry entry;
struct grub_partition *p = dev->disk->partition;
grub_disk_t disk = grub_disk_open(dev->disk->name);
if (!disk)
return grub_errno;
if (grub_disk_read(disk, p->offset, p->index, sizeof(entry), &entry))
return grub_errno;
grub_disk_close(disk);
grub_gpt_part_guid_t *guid = &entry.guid;
grub_snprintf (val, sizeof(val),
"%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
grub_le_to_cpu32 (guid->data1),
grub_le_to_cpu16 (guid->data2),
grub_le_to_cpu16 (guid->data3),
guid->data4[0], guid->data4[1], guid->data4[2],
guid->data4[3], guid->data4[4], guid->data4[5],
guid->data4[6], guid->data4[7]);
}
if (state[0].set)
grub_env_set (state[0].arg, val);
else
grub_printf ("%s", val);
grub_device_close (dev);
return GRUB_ERR_NONE;
}
fs = grub_fs_probe (dev);
if (! fs)
return grub_errno;