part: Add accessors for struct disk_partition uuid

This field is only present when a CONFIG is set. To avoid annoying #ifdefs
in the source code, add accessors. Update all code to use it.

Note that the accessor is optional. It can be omitted if it is known that
the option is enabled.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/gpt.c b/cmd/gpt.c
index 007a68e..8969efb 100644
--- a/cmd/gpt.c
+++ b/cmd/gpt.c
@@ -211,12 +211,10 @@
 		PART_TYPE_LEN);
 	newpart->gpt_part_info.type[PART_TYPE_LEN - 1] = '\0';
 	newpart->gpt_part_info.bootable = info->bootable;
-#ifdef CONFIG_PARTITION_UUIDS
-	strncpy(newpart->gpt_part_info.uuid, (const char *)info->uuid,
-		UUID_STR_LEN);
-	/* UUID_STR_LEN is correct, as uuid[]'s length is UUID_STR_LEN+1 chars */
-	newpart->gpt_part_info.uuid[UUID_STR_LEN] = '\0';
-#endif
+	if (IS_ENABLED(CONFIG_PARTITION_UUIDS)) {
+		strlcpy(newpart->gpt_part_info.uuid, disk_partition_uuid(info),
+			UUID_STR_LEN + 1);
+	}
 	newpart->partnum = partnum;
 
 	return newpart;
diff --git a/disk/part.c b/disk/part.c
index 9190e88..91c6ac4 100644
--- a/disk/part.c
+++ b/disk/part.c
@@ -368,10 +368,8 @@
 	struct part_driver *drv;
 
 	if (blk_enabled()) {
-#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
 		/* The common case is no UUID support */
-		info->uuid[0] = 0;
-#endif
+		disk_partition_clr_uuid(info);
 #ifdef CONFIG_PARTITION_TYPE_GUID
 		info->type_guid[0] = 0;
 #endif
@@ -416,9 +414,7 @@
 	info->bootable = 0;
 	strcpy((char *)info->type, BOOT_PART_TYPE);
 	strcpy((char *)info->name, "Whole Disk");
-#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
-	info->uuid[0] = 0;
-#endif
+	disk_partition_clr_uuid(info);
 #ifdef CONFIG_PARTITION_TYPE_GUID
 	info->type_guid[0] = 0;
 #endif
diff --git a/disk/part_dos.c b/disk/part_dos.c
index cc050ca..3337438 100644
--- a/disk/part_dos.c
+++ b/disk/part_dos.c
@@ -231,10 +231,8 @@
 		return -1;
 	}
 
-#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
-	if (!ext_part_sector)
+	if (CONFIG_IS_ENABLED(PARTITION_UUIDS) && !ext_part_sector)
 		disksig = get_unaligned_le32(&buffer[DOS_PART_DISKSIG_OFFSET]);
-#endif
 
 	ret = part_get_info_whole_disk(desc, &wdinfo);
 	if (ret)
@@ -263,9 +261,12 @@
 			/* sprintf(info->type, "%d, pt->sys_ind); */
 			strcpy((char *)info->type, "U-Boot");
 			info->bootable = get_bootable(pt);
-#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
-			sprintf(info->uuid, "%08x-%02x", disksig, part_num);
-#endif
+			if (CONFIG_IS_ENABLED(PARTITION_UUIDS)) {
+				char str[12];
+
+				sprintf(str, "%08x-%02x", disksig, part_num);
+				disk_partition_set_uuid(info, str);
+			}
 			info->sys_ind = pt->sys_ind;
 			return 0;
 		}
@@ -302,9 +303,7 @@
 			info->blksz = DOS_PART_DEFAULT_SECTOR;
 		info->bootable = 0;
 		strcpy((char *)info->type, "U-Boot");
-#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
-		info->uuid[0] = 0;
-#endif
+		disk_partition_clr_uuid(info);
 		return 0;
 	}
 
diff --git a/disk/part_efi.c b/disk/part_efi.c
index 4ac2186..a6f7375 100644
--- a/disk/part_efi.c
+++ b/disk/part_efi.c
@@ -289,10 +289,11 @@
 		 print_efiname(&gpt_pte[part - 1]));
 	strcpy((char *)info->type, "U-Boot");
 	info->bootable = get_bootable(&gpt_pte[part - 1]);
-#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
-	uuid_bin_to_str(gpt_pte[part - 1].unique_partition_guid.b, info->uuid,
-			UUID_STR_FORMAT_GUID);
-#endif
+	if (CONFIG_IS_ENABLED(PARTITION_UUIDS)) {
+		uuid_bin_to_str(gpt_pte[part - 1].unique_partition_guid.b,
+				(char *)disk_partition_uuid(info),
+				UUID_STR_FORMAT_GUID);
+	}
 #ifdef CONFIG_PARTITION_TYPE_GUID
 	uuid_bin_to_str(gpt_pte[part - 1].partition_type_guid.b,
 			info->type_guid, UUID_STR_FORMAT_GUID);
@@ -415,10 +416,7 @@
 			le64_to_cpu(gpt_h->last_usable_lba);
 	int i, k;
 	size_t efiname_len, dosname_len;
-#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
-	char *str_uuid;
 	unsigned char *bin_uuid;
-#endif
 #ifdef CONFIG_PARTITION_TYPE_GUID
 	char *str_type_guid;
 	unsigned char *bin_type_guid;
@@ -487,16 +485,19 @@
 			&partition_basic_data_guid, 16);
 #endif
 
-#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
-		str_uuid = partitions[i].uuid;
-		bin_uuid = gpt_e[i].unique_partition_guid.b;
+		if (CONFIG_IS_ENABLED(PARTITION_UUIDS)) {
+			const char *str_uuid;
 
-		if (uuid_str_to_bin(str_uuid, bin_uuid, UUID_STR_FORMAT_GUID)) {
-			log_debug("Partition no. %d: invalid guid: %s\n",
-				  i, str_uuid);
-			return -EINVAL;
+			str_uuid = disk_partition_uuid(&partitions[i]);
+			bin_uuid = gpt_e[i].unique_partition_guid.b;
+
+			if (uuid_str_to_bin(str_uuid, bin_uuid,
+					    UUID_STR_FORMAT_GUID)) {
+				log_debug("Partition no. %d: invalid guid: %s\n",
+					  i, str_uuid);
+				return -EINVAL;
+			}
 		}
-#endif
 
 		/* partition attributes */
 		memset(&gpt_e[i].attributes, 0,
diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index d1476aa..8ff1fd0 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -110,9 +110,7 @@
 		info.name[0] = 0;
 		info.type[0] = 0;
 		info.bootable = 0;
-#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
-		info.uuid[0] = 0;
-#endif
+		disk_partition_clr_uuid(&info);
 	}
 
 	return fat_set_blk_dev(dev_desc, &info);
diff --git a/include/part.h b/include/part.h
index 3a6be75..8e5e543 100644
--- a/include/part.h
+++ b/include/part.h
@@ -80,6 +80,33 @@
 #endif
 };
 
+/* Accessors for struct disk_partition field ->uuid */
+extern char *__invalid_use_of_disk_partition_uuid;
+
+static inline const char *disk_partition_uuid(const struct disk_partition *info)
+{
+#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
+	return info->uuid;
+#else
+	return __invalid_use_of_disk_partition_uuid;
+#endif
+}
+
+static inline void disk_partition_set_uuid(struct disk_partition *info,
+					   const char *val)
+{
+#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
+	strlcpy(info->uuid, val, UUID_STR_LEN + 1);
+#endif
+}
+
+static inline void disk_partition_clr_uuid(struct disk_partition *info)
+{
+#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
+	*info->uuid = '\0';
+#endif
+}
+
 struct disk_part {
 	int partnum;
 	struct disk_partition gpt_part_info;