From 46a8693953333e08fd2df4f722483b8db0f7da62 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Renaud=20M=C3=A9trich?= <rmetrich@redhat.com>
Date: Tue, 1 Feb 2022 07:17:24 +0100
Subject: [PATCH] search: new --efidisk-only option on EFI systems
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

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>

diff --git a/grub-core/commands/search.c b/grub-core/commands/search.c
index ed090b3af..5e1e88643 100644
--- a/grub-core/commands/search.c
+++ b/grub-core/commands/search.c
@@ -48,6 +48,9 @@ struct search_ctx
   const char *key;
   const char *var;
   int no_floppy;
+#ifdef GRUB_MACHINE_EFI
+  int efidisk_only;
+#endif
   char **hints;
   unsigned nhints;
   int count;
@@ -64,7 +67,28 @@ iterate_device (const char *name, void *data)
   /* Skip floppy drives when requested.  */
   if (ctx->no_floppy &&
       name[0] == 'f' && name[1] == 'd' && name[2] >= '0' && name[2] <= '9')
-    return 1;
+    return 0;
+
+#ifdef GRUB_MACHINE_EFI
+  /* Limit to EFI disks when requested.  */
+  if (ctx->efidisk_only)
+    {
+      grub_device_t dev;
+      dev = grub_device_open (name);
+      if (! dev)
+	{
+	  grub_errno = GRUB_ERR_NONE;
+	  return 0;
+	}
+      if (! dev->disk || dev->disk->dev->id != GRUB_DISK_DEVICE_EFIDISK_ID)
+	{
+	  grub_device_close (dev);
+	  grub_errno = GRUB_ERR_NONE;
+	  return 0;
+	}
+      grub_device_close (dev);
+    }
+#endif
 
 #ifdef DO_SEARCH_FS_UUID
 #define compare_fn grub_strcasecmp
@@ -262,12 +286,18 @@ try (struct search_ctx *ctx)
 
 void
 FUNC_NAME (const char *key, const char *var, int no_floppy,
+#ifdef GRUB_MACHINE_EFI
+	   int efidisk_only,
+#endif
 	   char **hints, unsigned nhints)
 {
   struct search_ctx ctx = {
     .key = key,
     .var = var,
     .no_floppy = no_floppy,
+#ifdef GRUB_MACHINE_EFI
+    .efidisk_only = efidisk_only,
+#endif
     .hints = hints,
     .nhints = nhints,
     .count = 0,
@@ -303,8 +333,12 @@ grub_cmd_do_search (grub_command_t cmd __attribute__ ((unused)), int argc,
   if (argc == 0)
     return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("one argument expected"));
 
-  FUNC_NAME (args[0], argc == 1 ? 0 : args[1], 0, (args + 2),
-	     argc > 2 ? argc - 2 : 0);
+  FUNC_NAME (args[0], argc == 1 ? 0 : args[1], 0,
+#ifdef GRUB_MACHINE_EFI
+	     /* efidisk_only */
+	     0,
+#endif
+	     (args + 2), argc > 2 ? argc - 2 : 0);
 
   return grub_errno;
 }
diff --git a/grub-core/commands/search_wrap.c b/grub-core/commands/search_wrap.c
index 47fc8eb99..aed75b236 100644
--- a/grub-core/commands/search_wrap.c
+++ b/grub-core/commands/search_wrap.c
@@ -40,6 +40,9 @@ 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},
+#ifdef GRUB_MACHINE_EFI
+    {"efidisk-only",	0, 0, N_("Only probe EFI disks."), 0, 0},
+#endif
     {"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 +76,9 @@ enum options
     SEARCH_FS_UUID,
     SEARCH_SET,
     SEARCH_NO_FLOPPY,
+#ifdef GRUB_MACHINE_EFI
+    SEARCH_EFIDISK_ONLY,
+#endif
     SEARCH_HINT,
     SEARCH_HINT_IEEE1275,
     SEARCH_HINT_BIOS,
@@ -182,12 +188,21 @@ grub_cmd_search (grub_extcmd_context_t ctxt, int argc, char **args)
 
   if (state[SEARCH_LABEL].set)
     grub_search_label (id, var, state[SEARCH_NO_FLOPPY].set, 
+#ifdef GRUB_MACHINE_EFI
+		       state[SEARCH_EFIDISK_ONLY].set,
+#endif
 		       hints, nhints);
   else if (state[SEARCH_FS_UUID].set)
     grub_search_fs_uuid (id, var, state[SEARCH_NO_FLOPPY].set,
+#ifdef GRUB_MACHINE_EFI
+			 state[SEARCH_EFIDISK_ONLY].set,
+#endif
 			 hints, nhints);
   else if (state[SEARCH_FILE].set)
     grub_search_fs_file (id, var, state[SEARCH_NO_FLOPPY].set, 
+#ifdef GRUB_MACHINE_EFI
+			 state[SEARCH_EFIDISK_ONLY].set,
+#endif
 			 hints, nhints);
   else
     grub_error (GRUB_ERR_INVALID_COMMAND, "unspecified search type");
diff --git a/include/grub/search.h b/include/grub/search.h
index d80347df3..fc058add2 100644
--- a/include/grub/search.h
+++ b/include/grub/search.h
@@ -20,10 +20,19 @@
 #define GRUB_SEARCH_HEADER 1
 
 void grub_search_fs_file (const char *key, const char *var, int no_floppy,
+#ifdef GRUB_MACHINE_EFI
+			  int efidisk_only,
+#endif
 			  char **hints, unsigned nhints);
 void grub_search_fs_uuid (const char *key, const char *var, int no_floppy,
+#ifdef GRUB_MACHINE_EFI
+			  int efidisk_only,
+#endif
 			  char **hints, unsigned nhints);
 void grub_search_label (const char *key, const char *var, int no_floppy,
+#ifdef GRUB_MACHINE_EFI
+			int efidisk_only,
+#endif
 			char **hints, unsigned nhints);
 
 #endif
-- 
2.34.1