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Re: [PATCH v2] search: Support searching for GPT partition label
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From: |
Sean Nyekjaer |
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Subject: |
Re: [PATCH v2] search: Support searching for GPT partition label |
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Date: |
Mon, 19 Sep 2022 11:12:15 +0200 |
On Fri, Sep 09, 2022 at 11:49:13AM +0200, Daniel Wagenknecht wrote:
> GPT partitions have a name property that is useable for identifying the
> partition in Linux via root=PARTLABEL=<partlabel> boot argument or via
> /dev/disk/by-partlabel/<partlabel>. Add support for searching for it in
> GRUB. Compared to the fs label, the partition label does not change when
> reformatting a partition.
>
> Signed-off-by: Daniel Wagenknecht <dwagenknecht@emlix.com>
Tested-by: Sean Nyekjaer <sean@geanix.com>
> ---
>
> This is a resend of a patch from 2020. Glenn Washburn suggested to rebase and
> resend with Daniel Kiper explicitely added to the recipients.
>
> The rebase required some changes to adapt to the changes in no_floppy search
> flags but is otherwise unchanged.
>
> Tested by manually searching for a partition by GPT partition label in grub in
> qemu.
>
> Cheers
> Daniel Wagenknecht
>
>
> grub-core/Makefile.core.def | 5 +++
> grub-core/commands/search.c | 57 +++++++++++++++++++++++++++
> grub-core/commands/search_partlabel.c | 5 +++
> grub-core/commands/search_wrap.c | 9 ++++-
> include/grub/search.h | 3 ++
> 5 files changed, 77 insertions(+), 2 deletions(-)
> create mode 100644 grub-core/commands/search_partlabel.c
>
> diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
> index 5212dfab1..d76c47113 100644
> --- a/grub-core/Makefile.core.def
> +++ b/grub-core/Makefile.core.def
> @@ -1084,6 +1084,11 @@ module = {
> common = commands/search_label.c;
> };
>
> +module = {
> + name = search_part_label;
> + common = commands/search_partlabel.c;
> +};
> +
> module = {
> name = setpci;
> common = commands/setpci.c;
> diff --git a/grub-core/commands/search.c b/grub-core/commands/search.c
> index 263f1501c..56aa97278 100644
> --- a/grub-core/commands/search.c
> +++ b/grub-core/commands/search.c
> @@ -30,6 +30,8 @@
> #include <grub/i18n.h>
> #include <grub/disk.h>
> #include <grub/partition.h>
> +#include <grub/gpt_partition.h>
> +#include <grub/charset.h>
>
> GRUB_MOD_LICENSE ("GPLv3+");
>
> @@ -54,6 +56,29 @@ struct search_ctx
> int is_cache;
> };
>
> +/* helper for grub_search_part_label */
> +static char *
> +get_utf8 (grub_uint8_t *in, grub_size_t len)
> +{
> + grub_uint8_t *buf;
> + grub_uint16_t *tmp;
> + grub_size_t i;
> +
> + buf = grub_malloc (len * GRUB_MAX_UTF8_PER_UTF16 + 1);
> + tmp = grub_malloc (len * sizeof (tmp[0]));
> + if (!buf || !tmp)
> + {
> + grub_free (buf);
> + grub_free (tmp);
> + return NULL;
> + }
> + for (i = 0; i < len; i++)
> + tmp[i] = grub_le_to_cpu16 (grub_get_unaligned16 (in + 2 * i));
> + *grub_utf16_to_utf8 (buf, tmp, len) = '\0';
> + grub_free (tmp);
> + return (char *) buf;
> +}
> +
> /* Helper for FUNC_NAME. */
> static int
> iterate_device (const char *name, void *data)
> @@ -110,6 +135,34 @@ iterate_device (const char *name, void *data)
> }
> grub_free (buf);
> }
> +#elif defined (DO_SEARCH_PART_LABEL)
> + {
> + grub_device_t dev;
> + char *buf;
> +
> + dev = grub_device_open (name);
> + if (dev && dev->disk && dev->disk->partition)
> + {
> + grub_partition_t p = dev->disk->partition;
> + grub_disk_t disk = grub_disk_open(dev->disk->name);
> +
> + if (!disk)
> + return 1;
> + if (grub_strcmp (p->partmap->name, "gpt") == 0)
> + {
> + struct grub_gpt_partentry gptdata;
> +
> + if (grub_disk_read (disk, p->offset, p->index, sizeof (gptdata),
> &gptdata))
> + return 1;
> + buf = get_utf8(gptdata.name, 36);
> + if (compare_fn (buf, ctx->key) == 0)
> + found = 1;
> + grub_free (buf);
> + }
> + grub_disk_close(disk);
> + grub_device_close (dev);
> + }
> + }
> #else
> {
> /* SEARCH_FS_UUID or SEARCH_LABEL */
> @@ -333,6 +386,8 @@ static grub_command_t cmd;
>
> #ifdef DO_SEARCH_FILE
> GRUB_MOD_INIT(search_fs_file)
> +#elif defined (DO_SEARCH_PART_LABEL)
> +GRUB_MOD_INIT(search_part_label)
> #elif defined (DO_SEARCH_FS_UUID)
> GRUB_MOD_INIT(search_fs_uuid)
> #else
> @@ -347,6 +402,8 @@ GRUB_MOD_INIT(search_label)
>
> #ifdef DO_SEARCH_FILE
> GRUB_MOD_FINI(search_fs_file)
> +#elif defined (DO_SEARCH_PART_LABEL)
> +GRUB_MOD_FINI(search_part_label)
> #elif defined (DO_SEARCH_FS_UUID)
> GRUB_MOD_FINI(search_fs_uuid)
> #else
> diff --git a/grub-core/commands/search_partlabel.c
> b/grub-core/commands/search_partlabel.c
> new file mode 100644
> index 000000000..8784d909e
> --- /dev/null
> +++ b/grub-core/commands/search_partlabel.c
> @@ -0,0 +1,5 @@
> +#define DO_SEARCH_PART_LABEL 1
> +#define FUNC_NAME grub_search_part_label
> +#define COMMAND_NAME "search.part_label"
> +#define HELP_MESSAGE N_("Search devices by GPT partition label. If VARIABLE
> is specified, the first device found is set to a variable.")
> +#include "search.c"
> diff --git a/grub-core/commands/search_wrap.c
> b/grub-core/commands/search_wrap.c
> index 318581f3b..6d1935bed 100644
> --- a/grub-core/commands/search_wrap.c
> +++ b/grub-core/commands/search_wrap.c
> @@ -34,6 +34,8 @@ static const struct grub_arg_option options[] =
> {"file", 'f', 0, N_("Search devices by a file."), 0, 0},
> {"label", 'l', 0, N_("Search devices by a filesystem
> label."),
> 0, 0},
> + {"part-label", 0, 0, N_("Search devices by a GPT partition label."),
> + 0, 0},
> {"fs-uuid", 'u', 0, N_("Search devices by a filesystem
> UUID."),
> 0, 0},
> {"set", 's', GRUB_ARG_OPTION_OPTIONAL,
> @@ -71,6 +73,7 @@ enum options
> {
> SEARCH_FILE,
> SEARCH_LABEL,
> + SEARCH_PART_LABEL,
> SEARCH_FS_UUID,
> SEARCH_SET,
> SEARCH_NO_FLOPPY,
> @@ -191,6 +194,8 @@ grub_cmd_search (grub_extcmd_context_t ctxt, int argc,
> char **args)
>
> if (state[SEARCH_LABEL].set)
> grub_search_label (id, var, flags, hints, nhints);
> + else if (state[SEARCH_PART_LABEL].set)
> + grub_search_part_label (id, var, flags, hints, nhints);
> else if (state[SEARCH_FS_UUID].set)
> grub_search_fs_uuid (id, var, flags, hints, nhints);
> else if (state[SEARCH_FILE].set)
> @@ -212,8 +217,8 @@ GRUB_MOD_INIT(search)
> GRUB_COMMAND_FLAG_EXTRACTOR |
> GRUB_COMMAND_ACCEPT_DASH,
> N_("[-f|-l|-u|-s|-n] [--hint HINT [--hint HINT] ...]"
> " NAME"),
> - N_("Search devices by file, filesystem label"
> - " or filesystem UUID."
> + N_("Search devices by file, filesystem label,"
> + " GPT partition label or filesystem UUID."
> " If --set is specified, the first device found is"
> " set to a variable. If no variable name is"
> " specified, `root' is used."),
> diff --git a/include/grub/search.h b/include/grub/search.h
> index ffd2411ca..ce61078a0 100644
> --- a/include/grub/search.h
> +++ b/include/grub/search.h
> @@ -35,5 +35,8 @@ void grub_search_fs_uuid (const char *key, const char *var,
> void grub_search_label (const char *key, const char *var,
> enum search_flags flags,
> char **hints, unsigned nhints);
> +void grub_search_part_label (const char *key, const char *var,
> + enum search_flags flags,
> + char **hints, unsigned nhints);
>
> #endif
> --
> 2.36.0
>
--
Best regards
Sean Nyekjær
Embedded Linux Consultant
+45 42427326
sean@geanix.com
Geanix ApS
https://geanix.com
DK39600706