[RFC PATCH] Add new partition type API and convert GPT type checks.

[Michael Marineau]

This introduces a new type() function for partmaps modeled after the
label() and uuid() functions for filesystems. A likely future extension
will be support partition labels and uuids as well. This is in
preparation for adding more functionality like a search.part_type
command.

The msdos partition code is only partially converted for now, I'm not
sure about the preferred way to do this. Re-reading a msdos partition
table is not as easy as re-reading gpt is. One option would be to turn
'msdostype' into a union or data pointer that partmap modules can stash
extra info in. That would also allow gpt to avoid re-reading. Being new
to grub, are there memory usage concerns I should be aware of here?
---
 grub-core/disk/ldm.c         | 17 ++----------
 grub-core/kern/partition.c   | 23 +++++++++++++++++
 grub-core/partmap/gpt.c      | 61 ++++++++++++++++++++++++++++++--------------
 grub-core/partmap/msdos.c    |  9 +++++++
 include/grub/gpt_partition.h | 20 +++------------
 include/grub/partition.h     | 11 ++++++++
 util/grub-install.c          | 34 ++++--------------------
 util/grub-probe.c            | 54 +++++++++++++++------------------------
 8 files changed, 117 insertions(+), 112 deletions(-)

diff --git a/grub-core/disk/ldm.c b/grub-core/disk/ldm.c
index 8075f2a..6dcfbc8 100644
--- a/grub-core/disk/ldm.c
+++ b/grub-core/disk/ldm.c
@@ -135,31 +135,18 @@ msdos_has_ldm_partition (grub_disk_t dsk)
   return has_ldm;
 }
 
-static const grub_gpt_part_type_t ldm_type = GRUB_GPT_PARTITION_TYPE_LDM;
-
 /* Helper for gpt_ldm_sector.  */
 static int
 gpt_ldm_sector_iter (grub_disk_t disk, const grub_partition_t p, void *data)
 {
   grub_disk_addr_t *sector = data;
-  struct grub_gpt_partentry gptdata;
-  grub_partition_t p2;
-
-  p2 = disk->partition;
-  disk->partition = p->parent;
-  if (grub_disk_read (disk, p->offset, p->index,
-                     sizeof (gptdata), &gptdata))
-    {
-      disk->partition = p2;
-      return 0;
-    }
-  disk->partition = p2;
 
-  if (! grub_memcmp (&gptdata.type, &ldm_type, 16))
+  if (grub_partition_is_type (disk, p, "gpt", GRUB_GPT_PARTITION_TYPE_LDM))
     {
       *sector = p->start + p->len - 1;
       return 1;
     }
+
   return 0;
 }
 
diff --git a/grub-core/kern/partition.c b/grub-core/kern/partition.c
index e499147..f27a8bd 100644
--- a/grub-core/kern/partition.c
+++ b/grub-core/kern/partition.c
@@ -274,3 +274,26 @@ grub_partition_get_name (const grub_partition_t partition)
   grub_memmove (out, ptr + 1, out + needlen - ptr);
   return out;
 }
+
+int grub_partition_is_type (struct grub_disk *disk,
+                           const grub_partition_t partition,
+                           const char *partmap_name,
+                           const char *partition_type)
+{
+  char *type;
+  int r;
+
+  if (!disk || !partition || !partition->partmap->type)
+    return 0;
+
+  if (grub_strcmp (partition->partmap->name, partmap_name) != 0)
+    return 0;
+
+  if (partition->partmap->type(disk, partition, &type) != 0)
+    return 0;
+
+  r = grub_strcmp (type, partition_type);
+  grub_free (type);
+
+  return r == 0;
+}
diff --git a/grub-core/partmap/gpt.c b/grub-core/partmap/gpt.c
index 38df7b3..6d6c13f 100644
--- a/grub-core/partmap/gpt.c
+++ b/grub-core/partmap/gpt.c
@@ -33,11 +33,10 @@ static grub_uint8_t grub_gpt_magic[8] =
     0x45, 0x46, 0x49, 0x20, 0x50, 0x41, 0x52, 0x54
   };
 
-static const grub_gpt_part_type_t grub_gpt_partition_type_empty = 
GRUB_GPT_PARTITION_TYPE_EMPTY;
-
-#ifdef GRUB_UTIL
-static const grub_gpt_part_type_t grub_gpt_partition_type_bios_boot = 
GRUB_GPT_PARTITION_TYPE_BIOS_BOOT;
-#endif
+static const grub_gpt_part_type_t grub_gpt_partition_type_empty =
+  { 0x0, 0x0, 0x0,
+    { 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 }
+  };
 
 /* 512 << 7 = 65536 byte sectors.  */
 #define MAX_SECTOR_LOG 7
@@ -128,6 +127,40 @@ grub_gpt_partition_map_iterate (grub_disk_t disk,
   return GRUB_ERR_NONE;
 }
 
+static grub_err_t
+grub_gpt_partition_type (grub_disk_t disk, const grub_partition_t partition,
+                        char **type)
+{
+  struct grub_gpt_partentry gptentry;
+  grub_gpt_part_type_t gpttype;
+  grub_partition_t p2;
+  grub_err_t err;
+
+  p2 = disk->partition;
+  disk->partition = partition->parent;
+  err = grub_disk_read (disk, partition->offset, partition->index,
+                       sizeof (gptentry), &gptentry);
+  disk->partition = p2;
+
+  if (err)
+    return err;
+
+  gpttype.data1 = grub_le_to_cpu32 (gptentry.type.data1);
+  gpttype.data2 = grub_le_to_cpu16 (gptentry.type.data2);
+  gpttype.data3 = grub_le_to_cpu16 (gptentry.type.data3);
+  grub_memcpy (gpttype.data4, gptentry.type.data4, sizeof (gpttype.data4));
+
+  *type = grub_xasprintf ("%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+                         gpttype.data1, gpttype.data2,
+                         gpttype.data3, gpttype.data4[0],
+                         gpttype.data4[1], gpttype.data4[2],
+                         gpttype.data4[3], gpttype.data4[4],
+                         gpttype.data4[5], gpttype.data4[6],
+                         gpttype.data4[7]);
+
+  return GRUB_ERR_NONE;
+}
+
 #ifdef GRUB_UTIL
 /* Context for gpt_partition_map_embed.  */
 struct gpt_partition_map_embed_ctx
@@ -137,25 +170,14 @@ struct gpt_partition_map_embed_ctx
 
 /* Helper for gpt_partition_map_embed.  */
 static int
-find_usable_region (grub_disk_t disk __attribute__ ((unused)),
+find_usable_region (grub_disk_t disk,
                    const grub_partition_t p, void *data)
 {
   struct gpt_partition_map_embed_ctx *ctx = data;
-  struct grub_gpt_partentry gptdata;
-  grub_partition_t p2;
-
-  p2 = disk->partition;
-  disk->partition = p->parent;
-  if (grub_disk_read (disk, p->offset, p->index,
-                     sizeof (gptdata), &gptdata))
-    {
-      disk->partition = p2;
-      return 0;
-    }
-  disk->partition = p2;
 
   /* If there's an embed region, it is in a dedicated partition.  */
-  if (! grub_memcmp (&gptdata.type, &grub_gpt_partition_type_bios_boot, 16))
+  if (grub_partition_is_type(disk, p, "gpt",
+                            GRUB_GPT_PARTITION_TYPE_BIOS_BOOT))
     {
       ctx->start = p->start;
       ctx->len = p->len;
@@ -215,6 +237,7 @@ static struct grub_partition_map grub_gpt_partition_map =
   {
     .name = "gpt",
     .iterate = grub_gpt_partition_map_iterate,
+    .type = grub_gpt_partition_type,
 #ifdef GRUB_UTIL
     .embed = gpt_partition_map_embed
 #endif
diff --git a/grub-core/partmap/msdos.c b/grub-core/partmap/msdos.c
index 1d81a53..68140a7 100644
--- a/grub-core/partmap/msdos.c
+++ b/grub-core/partmap/msdos.c
@@ -228,6 +228,14 @@ grub_partition_msdos_iterate (grub_disk_t disk,
   return grub_errno;
 }
 
+static grub_err_t
+grub_partition_msdos_type (grub_disk_t disk __attribute__ ((unused)),
+                          const grub_partition_t partition, char **type)
+{
+  *type = grub_xasprintf ("%02x", partition->msdostype);
+  return GRUB_ERR_NONE;
+}
+
 #ifdef GRUB_UTIL
 
 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
@@ -415,6 +423,7 @@ static struct grub_partition_map grub_msdos_partition_map =
   {
     .name = "msdos",
     .iterate = grub_partition_msdos_iterate,
+    .type = grub_partition_msdos_type,
 #ifdef GRUB_UTIL
     .embed = pc_partition_map_embed
 #endif
diff --git a/include/grub/gpt_partition.h b/include/grub/gpt_partition.h
index 1b32f67..566334c 100644
--- a/include/grub/gpt_partition.h
+++ b/include/grub/gpt_partition.h
@@ -31,24 +31,12 @@ struct grub_gpt_part_type
 } __attribute__ ((aligned(8)));
 typedef struct grub_gpt_part_type grub_gpt_part_type_t;
 
-#define GRUB_GPT_PARTITION_TYPE_EMPTY \
-  { 0x0, 0x0, 0x0, \
-    { 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 } \
-  }
-
 #define GRUB_GPT_PARTITION_TYPE_BIOS_BOOT \
-  { grub_cpu_to_le32_compile_time (0x21686148), \
-      grub_cpu_to_le16_compile_time (0x6449), \
-      grub_cpu_to_le16_compile_time (0x6e6f),         \
-    { 0x74, 0x4e, 0x65, 0x65, 0x64, 0x45, 0x46, 0x49 } \
-  }
-
+  "21686148-6449-6e6f-744e-656564454649"
 #define GRUB_GPT_PARTITION_TYPE_LDM \
-  { grub_cpu_to_le32_compile_time (0x5808C8AAU),\
-      grub_cpu_to_le16_compile_time (0x7E8F), \
-      grub_cpu_to_le16_compile_time (0x42E0),         \
-       { 0x85, 0xD2, 0xE1, 0xE9, 0x04, 0x34, 0xCF, 0xB3 }      \
-  }
+  "5808c8aa-7e8f-42e0-85d2-e1e90434cfb3"
+#define GRUB_GPT_PARTITION_TYPE_PREP \
+  "9e1a2d38-c612-4316-aa26-8b49521e5a8b"
 
 struct grub_gpt_header
 {
diff --git a/include/grub/partition.h b/include/grub/partition.h
index 7adb7ec..3dc46bf 100644
--- a/include/grub/partition.h
+++ b/include/grub/partition.h
@@ -50,6 +50,13 @@ struct grub_partition_map
   /* Call HOOK with each partition, until HOOK returns non-zero.  */
   grub_err_t (*iterate) (struct grub_disk *disk,
                         grub_partition_iterate_hook_t hook, void *hook_data);
+
+  /* Return the type of the partition PARTITION in TYPE.
+     The type is returned in a grub_malloc'ed buffer and should
+     be freed by the caller.  */
+  grub_err_t (*type) (struct grub_disk *disk,
+                     const grub_partition_t partition, char **type);
+
 #ifdef GRUB_UTIL
   /* Determine sectors available for embedding.  */
   grub_err_t (*embed) (struct grub_disk *disk, unsigned int *nsectors,
@@ -95,6 +102,10 @@ int EXPORT_FUNC(grub_partition_iterate) (struct grub_disk 
*disk,
                                         grub_partition_iterate_hook_t hook,
                                         void *hook_data);
 char *EXPORT_FUNC(grub_partition_get_name) (const grub_partition_t partition);
+int EXPORT_FUNC(grub_partition_is_type) (struct grub_disk *disk,
+                                        const grub_partition_t partition,
+                                        const char *partmap_name,
+                                        const char *partition_type);
 
 
 extern grub_partition_map_t EXPORT_VAR(grub_partition_map_list);
diff --git a/util/grub-install.c b/util/grub-install.c
index 7d61c32..ee98b70 100644
--- a/util/grub-install.c
+++ b/util/grub-install.c
@@ -696,36 +696,12 @@ write_to_disk (grub_device_t dev, const char *fn)
 static int
 is_prep_partition (grub_device_t dev)
 {
-  if (!dev->disk)
-    return 0;
-  if (!dev->disk->partition)
-    return 0;
-  if (strcmp(dev->disk->partition->partmap->name, "msdos") == 0)
-    return (dev->disk->partition->msdostype == 0x41);
-
-  if (strcmp (dev->disk->partition->partmap->name, "gpt") == 0)
-    {
-      struct grub_gpt_partentry gptdata;
-      grub_partition_t p = dev->disk->partition;
-      int ret = 0;
-      dev->disk->partition = dev->disk->partition->parent;
+  if (grub_partition_is_type (dev->disk, dev->disk->partition, "msdos", "41"))
+    return 1;
 
-      if (grub_disk_read (dev->disk, p->offset, p->index,
-                         sizeof (gptdata), &gptdata) == 0)
-       {
-         const grub_gpt_part_type_t template = {
-           grub_cpu_to_le32_compile_time (0x9e1a2d38),
-           grub_cpu_to_le16_compile_time (0xc612),
-           grub_cpu_to_le16_compile_time (0x4316),
-           { 0xaa, 0x26, 0x8b, 0x49, 0x52, 0x1e, 0x5a, 0x8b }
-         };
-
-         ret = grub_memcmp (&template, &gptdata.type,
-                            sizeof (template)) == 0;
-       }
-      dev->disk->partition = p;
-      return ret;
-    }
+  if (grub_partition_is_type (dev->disk, dev->disk->partition,
+                             "gpt", GRUB_GPT_PARTITION_TYPE_PREP))
+    return 1;
 
   return 0;
 }
diff --git a/util/grub-probe.c b/util/grub-probe.c
index ecb7b6b..a2505f0 100644
--- a/util/grub-probe.c
+++ b/util/grub-probe.c
@@ -27,7 +27,6 @@
 #include <grub/fs.h>
 #include <grub/partition.h>
 #include <grub/msdos_partition.h>
-#include <grub/gpt_partition.h>
 #include <grub/emu/hostdisk.h>
 #include <grub/emu/getroot.h>
 #include <grub/term.h>
@@ -253,6 +252,25 @@ probe_abstraction (grub_disk_t disk, char delim)
 }
 
 static void
+probe_partition_type(grub_disk_t disk, const char *partmap, char delim)
+{
+  char *type;
+
+  if (!disk->partition || !disk->partition->partmap->type ||
+      strcmp(disk->partition->partmap->name, partmap) != 0)
+    {
+      putchar (delim);
+      return;
+    }
+
+  if (disk->partition->partmap->type(disk, disk->partition, &type))
+    grub_util_error ("%s", grub_errmsg);
+
+  printf ("%s%c", type, delim);
+  free(type);
+}
+
+static void
 probe (const char *path, char **device_names, char delim)
 {
   char **drives_names = NULL;
@@ -653,44 +671,14 @@ probe (const char *path, char **device_names, char delim)
 
       if (print == PRINT_MSDOS_PARTTYPE)
        {
-         if (dev->disk->partition
-             && strcmp(dev->disk->partition->partmap->name, "msdos") == 0)
-           printf ("%02x", dev->disk->partition->msdostype);
-
-         putchar (delim);
+         probe_partition_type(dev->disk, "msdos", delim);
          grub_device_close (dev);
          continue;
        }
 
       if (print == PRINT_GPT_PARTTYPE)
        {
-          if (dev->disk->partition
-             && strcmp (dev->disk->partition->partmap->name, "gpt") == 0)
-            {
-              struct grub_gpt_partentry gptdata;
-              grub_partition_t p = dev->disk->partition;
-              dev->disk->partition = dev->disk->partition->parent;
-
-              if (grub_disk_read (dev->disk, p->offset, p->index,
-                                  sizeof (gptdata), &gptdata) == 0)
-                {
-                  grub_gpt_part_type_t gpttype;
-                  gpttype.data1 = grub_le_to_cpu32 (gptdata.type.data1);
-                  gpttype.data2 = grub_le_to_cpu16 (gptdata.type.data2);
-                  gpttype.data3 = grub_le_to_cpu16 (gptdata.type.data3);
-                  grub_memcpy (gpttype.data4, gptdata.type.data4, 8);
-
-                  grub_printf 
("%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
-                               gpttype.data1, gpttype.data2,
-                               gpttype.data3, gpttype.data4[0], 
-                               gpttype.data4[1], gpttype.data4[2],
-                               gpttype.data4[3], gpttype.data4[4],
-                               gpttype.data4[5], gpttype.data4[6],
-                               gpttype.data4[7]);
-                }
-              dev->disk->partition = p;
-            }
-          putchar (delim);
+         probe_partition_type(dev->disk, "gpt", delim);
           grub_device_close (dev);
           continue;
         }
-- 
1.8.5.5