Identify RAID by its UUID rather than (guessed) name.

* grub-core/disk/raid.c (ascii2hex): New function.
	(grub_raid_open): Accept mduuid/%s specification.
	* grub-core/kern/emu/getroot.c (get_mdadm_name): Revamped into ...
	(get_mdadm_uuid): ... this.
	(grub_util_get_grub_dev): Use mduuid/%s if UUID is available.

ChangeLog

@@ -1,3 +1,13 @@
+2011-04-17  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	Identify RAID by its UUID rather than (guessed) name.
+
+	* grub-core/disk/raid.c (ascii2hex): New function.
+	(grub_raid_open): Accept mduuid/%s specification.
+	* grub-core/kern/emu/getroot.c (get_mdadm_name): Revamped into ...
+	(get_mdadm_uuid): ... this.
+	(grub_util_get_grub_dev): Use mduuid/%s if UUID is available.
+
 2011-04-16  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/gfxmenu/gui_image.c (rescale_image): Don't attempt to scale

grub-core/disk/raid.c

@@ -122,12 +122,43 @@ grub_raid_getname (struct grub_disk *disk)
 }
 #endif
 
+static inline int
+ascii2hex (char c)
+{
+  if (c >= '0' && c <= '9')
+    return c - '0';
+  if (c >= 'a' && c <= 'f')
+    return c - 'a' + 10;
+  if (c >= 'A' && c <= 'F')
+    return c - 'A' + 10;
+  return 0;
+}
+
 static grub_err_t
 grub_raid_open (const char *name, grub_disk_t disk)
 {
   struct grub_raid_array *array;
   unsigned n;
 
+  if (grub_memcmp (name, "mduuid/", sizeof ("mduuid/") - 1) == 0)
+    {
+      const char *uuidstr = name + sizeof ("mduuid/") - 1;
+      grub_size_t uuid_len = grub_strlen (uuidstr) / 2;
+      grub_uint8_t uuidbin[uuid_len];
+      unsigned i;
+      for (i = 0; i < uuid_len; i++)
+	uuidbin[i] = ascii2hex (uuidstr[2 * i + 1])
+	  | (ascii2hex (uuidstr[2 * i]) << 4);
+      
+      for (array = array_list; array != NULL; array = array->next)
+	{
+	  if (uuid_len == (unsigned) array->uuid_len
+	      && grub_memcmp (uuidbin, array->uuid, uuid_len) == 0)
+	    if (grub_is_array_readable (array))
+	      break;
+	}
+    }
+  else
     for (array = array_list; array != NULL; array = array->next)
       {
 	if (!grub_strcmp (array->name, name))

grub-core/kern/emu/getroot.c

@@ -690,7 +690,7 @@ grub_util_get_dev_abstraction (const char *os_dev __attribute__((unused)))
 
 #ifdef __linux__
 static char *
-get_mdadm_name (const char *os_dev)
+get_mdadm_uuid (const char *os_dev)
 {
   int mdadm_pipe[2];
   pid_t mdadm_pid;
@@ -742,19 +742,21 @@ get_mdadm_name (const char *os_dev)
 
       while (getline (&buf, &len, mdadm) > 0)
 	{
-	  if (strncmp (buf, "MD_NAME=", sizeof ("MD_NAME=") - 1) == 0)
+	  if (strncmp (buf, "MD_UUID=", sizeof ("MD_UUID=") - 1) == 0)
 	    {
-	      char *name_start, *colon;
+	      char *name_start, *ptri, *ptro;
 	      size_t name_len;
 
 	      free (name);
-	      name_start = buf + sizeof ("MD_NAME=") - 1;
+	      name_start = buf + sizeof ("MD_UUID=") - 1;
-	      /* Strip off the homehost if present.  */
+	      ptro = name = xmalloc (strlen (name_start) + 1);
-	      colon = strchr (name_start, ':');
+	      for (ptri = name_start; *ptri && *ptri != '\n' && *ptri != '\r';
-	      name = strdup (colon ? colon + 1 : name_start);
+		   ptri++)
-	      name_len = strlen (name);
+		if ((*ptri >= '0' && *ptri <= '9')
-	      if (name[name_len - 1] == '\n')
+		    || (*ptri >= 'a' && *ptri <= 'f')
-		name[name_len - 1] = '\0';
+		    || (*ptri >= 'A' && *ptri <= 'F'))
+		  *ptro++ = *ptri;
+	      *ptro = 0;
 	    }
 	}
 
@@ -870,37 +872,26 @@ grub_util_get_grub_dev (const char *os_dev)
 
 #ifdef __linux__
       {
-	char *mdadm_name = get_mdadm_name (os_dev);
+	char *mdadm_name = get_mdadm_uuid (os_dev);
 	struct stat st;
 
 	if (mdadm_name)
 	  {
-	    char *newname;
 	    const char *q;
 
 	    for (q = os_dev + strlen (os_dev) - 1; q >= os_dev
 		   && grub_isdigit (*q); q--);
 
 	    if (q >= os_dev && *q == 'p')
-	      {
-		newname = xasprintf ("/dev/md/%sp%s", mdadm_name, q + 1);
-		if (stat (newname, &st) == 0)
 	      {
 		free (grub_dev);
-		    grub_dev = xasprintf ("md/%s,%s", mdadm_name, q + 1);
+		grub_dev = xasprintf ("mduuid/%s,%s", mdadm_name, q + 1);
 		goto done;
 	      }
-		free (newname);
-	      }
-	    newname = xasprintf ("/dev/md/%s", mdadm_name);
-	    if (stat (newname, &st) == 0)
-	      {
 	    free (grub_dev);
-		grub_dev = xasprintf ("md/%s", mdadm_name);
+	    grub_dev = xasprintf ("mduuid/%s", mdadm_name);
-	      }
 
 	  done:
-	    free (newname);
 	    free (mdadm_name);
 	  }
       }