[PATCH v3 2/2] search: new --efidisk-only option on EFI systems

[Renaud Métrich]

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.

This commit also refactors handling of --no-floppy option.

Signed-off-by: Renaud Métrich <rmetrich@redhat.com>
---
 grub-core/commands/search.c      | 27 +++++++++++++++++++++++----
 grub-core/commands/search_wrap.c | 18 ++++++++++++------
 include/grub/search.h            | 15 ++++++++++++---
 3 files changed, 47 insertions(+), 13 deletions(-)

diff --git a/grub-core/commands/search.c b/grub-core/commands/search.c
index 51656e361..57d26ced8 100644
--- a/grub-core/commands/search.c
+++ b/grub-core/commands/search.c
@@ -47,7 +47,7 @@ struct search_ctx
 {
   const char *key;
   const char *var;
-  int no_floppy;
+  enum search_flags flags;
   char **hints;
   unsigned nhints;
   int count;
@@ -62,10 +62,29 @@ iterate_device (const char *name, void *data)
   int found = 0;
 
   /* Skip floppy drives when requested.  */
-  if (ctx->no_floppy &&
+  if (ctx->flags & SEARCH_FLAGS_NO_FLOPPY &&
       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)
+       {
+         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);
+    }
+
 #ifdef DO_SEARCH_FS_UUID
 #define compare_fn grub_strcasecmp
 #else
@@ -261,13 +280,13 @@ try (struct search_ctx *ctx)
 }
 
 void
-FUNC_NAME (const char *key, const char *var, int no_floppy,
+FUNC_NAME (const char *key, const char *var, enum search_flags flags,
           char **hints, unsigned nhints)
 {
   struct search_ctx ctx = {
     .key = key,
     .var = var,
-    .no_floppy = no_floppy,
+    .flags = flags,
     .hints = hints,
     .nhints = nhints,
     .count = 0,
diff --git a/grub-core/commands/search_wrap.c b/grub-core/commands/search_wrap.c
index 47fc8eb99..464e6ebb1 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,
@@ -89,6 +91,7 @@ grub_cmd_search (grub_extcmd_context_t ctxt, int argc, char 
**args)
   const char *id = 0;
   int i = 0, j = 0, nhints = 0;
   char **hints = NULL;
+  enum search_flags flags;
 
   if (state[SEARCH_HINT].set)
     for (i = 0; state[SEARCH_HINT].args[i]; i++)
@@ -180,15 +183,18 @@ grub_cmd_search (grub_extcmd_context_t ctxt, int argc, 
char **args)
       goto out;
     }
 
+  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, state[SEARCH_NO_FLOPPY].set, 
-                      hints, nhints);
+    grub_search_label (id, var, flags, hints, nhints);
   else if (state[SEARCH_FS_UUID].set)
-    grub_search_fs_uuid (id, var, state[SEARCH_NO_FLOPPY].set,
-                        hints, nhints);
+    grub_search_fs_uuid (id, var, flags, hints, nhints);
   else if (state[SEARCH_FILE].set)
-    grub_search_fs_file (id, var, state[SEARCH_NO_FLOPPY].set, 
-                        hints, nhints);
+    grub_search_fs_file (id, var, flags, 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..4190aeb2c 100644
--- a/include/grub/search.h
+++ b/include/grub/search.h
@@ -19,11 +19,20 @@
 #ifndef GRUB_SEARCH_HEADER
 #define GRUB_SEARCH_HEADER 1
 
-void grub_search_fs_file (const char *key, const char *var, int no_floppy,
+enum search_flags
+  {
+    SEARCH_FLAGS_NO_FLOPPY     = 1,
+    SEARCH_FLAGS_EFIDISK_ONLY  = 2
+  };
+
+void grub_search_fs_file (const char *key, const char *var,
+                         enum search_flags flags,
                          char **hints, unsigned nhints);
-void grub_search_fs_uuid (const char *key, const char *var, int no_floppy,
+void grub_search_fs_uuid (const char *key, const char *var,
+                         enum search_flags flags,
                          char **hints, unsigned nhints);
-void grub_search_label (const char *key, const char *var, int no_floppy,
+void grub_search_label (const char *key, const char *var,
+                       enum search_flags flags,
                        char **hints, unsigned nhints);
 
 #endif
-- 
2.34.1