commands/search: Add new --efidisk-only option for EFI systems

When using "search" on EFI systems, we sometimes want to exclude devices
that are not EFI disks, e.g. md, lvm. This is typically used when
wanting to chainload when having a software raid (md) for EFI partition:
with no option, "search --file /EFI/redhat/shimx64.efi" sets root envvar
to "md/boot_efi" which cannot be used for chainloading since there is no
effective EFI device behind.

Signed-off-by: Renaud Métrich <rmetrich@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

4 files changed, 31 insertions, 2 deletions

diff --git a/docs/grub.texi b/docs/grub.texi
index caba8befb..9835c878a 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -5043,7 +5043,7 @@ unbootable. @xref{Using digital signatures}, for more information.
 
 @deffn Command search @
  [@option{--file}|@option{--label}|@option{--fs-uuid}] @
- [@option{--set} [var]] [@option{--no-floppy}] name
+ [@option{--set} [var]] [@option{--no-floppy}|@option{--efidisk-only}] name
 Search devices by file (@option{-f}, @option{--file}), filesystem label
 (@option{-l}, @option{--label}), or filesystem UUID (@option{-u},
 @option{--fs-uuid}).
@@ -5055,6 +5055,9 @@ set as the value of environment variable @var{var}. The default variable is
 The (@option{-n}, @option{--no-floppy}) option prevents searching floppy
 devices, which can be slow.
 
+The (@option{--efidisk-only}) option prevents searching any other devices then
+EFI disks. This is typically used when chainloading to local EFI partition.
+
 The @samp{search.file}, @samp{search.fs_label}, and @samp{search.fs_uuid}
 commands are aliases for @samp{search --file}, @samp{search --label}, and
 @samp{search --fs-uuid} respectively.
diff --git a/grub-core/commands/search.c b/grub-core/commands/search.c
index 125113505..263f1501c 100644
--- a/grub-core/commands/search.c
+++ b/grub-core/commands/search.c
@@ -66,6 +66,26 @@ iterate_device (const char *name, void *data)
       name[0] == 'f' && name[1] == 'd' && name[2] >= '0' && name[2] <= '9')
     return 0;
 
+  /* Limit to EFI disks when requested.  */
+  if (ctx->flags & SEARCH_FLAGS_EFIDISK_ONLY)
+    {
+      grub_device_t dev;
+
+      dev = grub_device_open (name);
+      if (dev == NULL)
+	{
+	  grub_errno = GRUB_ERR_NONE;
+	  return 0;
+	}
+      if (dev->disk == NULL || dev->disk->dev->id != GRUB_DISK_DEVICE_EFIDISK_ID)
+	{
+	  grub_device_close (dev);
+	  grub_errno = GRUB_ERR_NONE;
+	  return 0;
+	}
+      grub_device_close (dev);
+    }
+
 #ifdef DO_SEARCH_FS_UUID
 #define compare_fn grub_strcasecmp
 #else
diff --git a/grub-core/commands/search_wrap.c b/grub-core/commands/search_wrap.c
index b79a2e99e..318581f3b 100644
--- a/grub-core/commands/search_wrap.c
+++ b/grub-core/commands/search_wrap.c
@@ -40,6 +40,7 @@ static const struct grub_arg_option options[] =
      N_("Set a variable to the first device found."), N_("VARNAME"),
      ARG_TYPE_STRING},
     {"no-floppy",	'n', 0, N_("Do not probe any floppy drive."), 0, 0},
+    {"efidisk-only",	0, 0, N_("Only probe EFI disks."), 0, 0},
     {"hint",	        'h', GRUB_ARG_OPTION_REPEATABLE,
      N_("First try the device HINT. If HINT ends in comma, "
 	"also try subpartitions"), N_("HINT"), ARG_TYPE_STRING},
@@ -73,6 +74,7 @@ enum options
     SEARCH_FS_UUID,
     SEARCH_SET,
     SEARCH_NO_FLOPPY,
+    SEARCH_EFIDISK_ONLY,
     SEARCH_HINT,
     SEARCH_HINT_IEEE1275,
     SEARCH_HINT_BIOS,
@@ -184,6 +186,9 @@ grub_cmd_search (grub_extcmd_context_t ctxt, int argc, char **args)
   if (state[SEARCH_NO_FLOPPY].set)
     flags |= SEARCH_FLAGS_NO_FLOPPY;
 
+  if (state[SEARCH_EFIDISK_ONLY].set)
+    flags |= SEARCH_FLAGS_EFIDISK_ONLY;
+
   if (state[SEARCH_LABEL].set)
     grub_search_label (id, var, flags, hints, nhints);
   else if (state[SEARCH_FS_UUID].set)
diff --git a/include/grub/search.h b/include/grub/search.h
index fa71cd950..ffd2411ca 100644
--- a/include/grub/search.h
+++ b/include/grub/search.h
@@ -22,7 +22,8 @@
 enum search_flags
   {
     SEARCH_FLAGS_NONE		= 0,
-    SEARCH_FLAGS_NO_FLOPPY	= 1
+    SEARCH_FLAGS_NO_FLOPPY	= 1,
+    SEARCH_FLAGS_EFIDISK_ONLY	= 2
   };
 
 void grub_search_fs_file (const char *key, const char *var,