On Fri, 10 May 2019, 19:05 Jacob Kroon, <jacob.kr...@gmail.com> wrote:
> 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.
>
> Signed-off-by: Jacob Kroon <jacob.kr...@gmail.com>
> ---
> grub-core/commands/probe.c | 35 +++++++++++++++++++++++++++++++++++
> 1 file changed, 35 insertions(+)
>
> Changes since v2:
>
> * Add a proper commit message
> * Handle endianess in the same way as is currently done in
> util/grub-probe.c:print_gpt_guid ()
>
> diff --git a/grub-core/commands/probe.c b/grub-core/commands/probe.c
> index 95d272287..24742c181 100644
> --- a/grub-core/commands/probe.c
> +++ b/grub-core/commands/probe.c
> @@ -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},
> + {"partuuid", 'q', 0, N_("Determine GPT partition uuid."), 0, 0},
> {0, 0, 0, 0, 0, 0}
> };
>
> @@ -98,6 +100,39 @@ 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;
> + guid->data1 = grub_le_to_cpu32 (guid->data1);
> + guid->data2 = grub_le_to_cpu16 (guid->data2);
> + guid->data3 = grub_le_to_cpu16 (guid->data3);
>
Please don't modify this in place. This can easily create hard to track
endian-dependent bug. Instead you can transform them right before printing,
in the same statement.
Otherwise the patch is fine
> + grub_snprintf (val, sizeof(val),
> +
> "%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
> + guid->data1, guid->data2, 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;
> --
> 2.20.1
>
>
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>
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