[PATCH] grub2: add support to search for partuuid

[Michael Grzeschik]

With this feature the grub-shell is able to search for partuuid strings.
This reduces the complexity to find the correct boot partition on
systems with unspecified device connectivity.

Signed-off-by: Michael Grzeschik <address@hidden>
---
 grub-core/Makefile.core.def          |  5 +++++
 grub-core/commands/search.c          | 25 ++++++++++++++++++++++++-
 grub-core/commands/search_partuuid.c |  5 +++++
 grub-core/commands/search_wrap.c     |  8 +++++++-
 grub-core/partmap/msdos.c            |  9 +++++++++
 include/grub/disk.h                  |  2 ++
 6 files changed, 52 insertions(+), 2 deletions(-)
 create mode 100644 grub-core/commands/search_partuuid.c

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 474a63e68..208feb934 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -1070,6 +1070,11 @@ module = {
   common = commands/search_file.c;
 };
 
+module = {
+  name = search_partuuid;
+  common = commands/search_partuuid.c;
+};
+
 module = {
   name = search_fs_uuid;
   common = commands/search_uuid.c;
diff --git a/grub-core/commands/search.c b/grub-core/commands/search.c
index ed090b3af..3ac93943b 100644
--- a/grub-core/commands/search.c
+++ b/grub-core/commands/search.c
@@ -72,7 +72,26 @@ iterate_device (const char *name, void *data)
 #define compare_fn grub_strcmp
 #endif
 
-#ifdef DO_SEARCH_FILE
+#ifdef (DO_SEARCH_PARTUUID)
+    {
+      grub_disk_t disk;
+      char *part_uuid;
+      char *uuid;
+
+      disk = grub_disk_open (name);
+      if (disk && disk->partition)
+       {
+          part_uuid = grub_xasprintf ("%08x-%02x", disk->nt_disk_sig,
+                                      disk->partition->index + 1);
+          if (compare_fn (part_uuid, ctx->key) == 0)
+                   found = 1;
+          if (part_uuid)
+            grub_free (part_uuid);
+        }
+      if (disk)
+        grub_disk_close (disk);
+    }
+#elif defined (DO_SEARCH_FILE)
     {
       char *buf;
       grub_file_t file;
@@ -313,6 +332,8 @@ static grub_command_t cmd;
 
 #ifdef DO_SEARCH_FILE
 GRUB_MOD_INIT(search_fs_file)
+#elif defined (DO_SEARCH_PARTUUID)
+GRUB_MOD_INIT(search_partuuid)
 #elif defined (DO_SEARCH_FS_UUID)
 GRUB_MOD_INIT(search_fs_uuid)
 #else
@@ -327,6 +348,8 @@ GRUB_MOD_INIT(search_label)
 
 #ifdef DO_SEARCH_FILE
 GRUB_MOD_FINI(search_fs_file)
+#elif defined (DO_SEARCH_PARTUUID)
+GRUB_MOD_FINI(search_partuuid)
 #elif defined (DO_SEARCH_FS_UUID)
 GRUB_MOD_FINI(search_fs_uuid)
 #else
diff --git a/grub-core/commands/search_partuuid.c 
b/grub-core/commands/search_partuuid.c
new file mode 100644
index 000000000..e4aa20b5f
--- /dev/null
+++ b/grub-core/commands/search_partuuid.c
@@ -0,0 +1,5 @@
+#define DO_SEARCH_PARTUUID 1
+#define FUNC_NAME grub_search_partuuid
+#define COMMAND_NAME "search.partuuid"
+#define HELP_MESSAGE N_("Search devices by PARTUUID. 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 d7fd26b94..ba36dbac2 100644
--- a/grub-core/commands/search_wrap.c
+++ b/grub-core/commands/search_wrap.c
@@ -36,6 +36,8 @@ static const struct grub_arg_option options[] =
      0, 0},
     {"fs-uuid",                'u', 0, N_("Search devices by a filesystem 
UUID."),
      0, 0},
+    {"partuuid",       'p', 0, N_("Search devices by a PARTUUID."),
+     0, 0},
     {"set",            's', GRUB_ARG_OPTION_OPTIONAL,
      N_("Set a variable to the first device found."), N_("VARNAME"),
      ARG_TYPE_STRING},
@@ -71,6 +73,7 @@ enum options
     SEARCH_FILE,
     SEARCH_LABEL,
     SEARCH_FS_UUID,
+    SEARCH_PARTUUID,
     SEARCH_SET,
     SEARCH_NO_FLOPPY,
     SEARCH_HINT,
@@ -186,6 +189,9 @@ grub_cmd_search (grub_extcmd_context_t ctxt, int argc, char 
**args)
   else if (state[SEARCH_FS_UUID].set)
     grub_search_fs_uuid (id, var, state[SEARCH_NO_FLOPPY].set,
                         hints, nhints);
+  else if (state[SEARCH_PARTUUID].set)
+    grub_search_partuuid (id, var, state[SEARCH_NO_FLOPPY].set,
+                        hints, nhints);
   else if (state[SEARCH_FILE].set)
     grub_search_fs_file (id, var, state[SEARCH_NO_FLOPPY].set, 
                         hints, nhints);
@@ -207,7 +213,7 @@ GRUB_MOD_INIT(search)
                          N_("[-f|-l|-u|-s|-n] [--hint HINT [--hint HINT] ...]"
                             " NAME"),
                          N_("Search devices by file, filesystem label"
-                            " or filesystem UUID."
+                            " PARTUUID 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/grub-core/partmap/msdos.c b/grub-core/partmap/msdos.c
index 7b8e45076..8a4af5931 100644
--- a/grub-core/partmap/msdos.c
+++ b/grub-core/partmap/msdos.c
@@ -19,6 +19,7 @@
 
 #include <grub/partition.h>
 #include <grub/msdos_partition.h>
+#include <grub/i386/pc/boot.h>
 #include <grub/disk.h>
 #include <grub/mm.h>
 #include <grub/misc.h>
@@ -134,6 +135,14 @@ grub_partition_msdos_iterate (grub_disk_t disk,
      first loop.  */
   lastaddr = !p.offset;
 
+  if (!disk->nt_disk_sig) {
+    grub_uint32_t nt_disk_sig;
+
+    if (grub_disk_read (disk, 0, GRUB_BOOT_MACHINE_WINDOWS_NT_MAGIC,
+                     sizeof(nt_disk_sig), &nt_disk_sig) == 0)
+      disk->nt_disk_sig = grub_le_to_cpu32(nt_disk_sig);
+  }
+
   while (1)
     {
       int i;
diff --git a/include/grub/disk.h b/include/grub/disk.h
index 316659fee..b489f957b 100644
--- a/include/grub/disk.h
+++ b/include/grub/disk.h
@@ -133,6 +133,8 @@ struct grub_disk
   /* The id used by the disk cache manager.  */
   unsigned long id;
 
+  grub_uint32_t nt_disk_sig;
+
   /* The partition information. This is machine-specific.  */
   struct grub_partition *partition;
 
-- 
2.20.1