efi_loader: use short-form DP for load options

The GUID of partitions is sufficient for identification and will stay
constant in the lifetime of a boot option. The preceding path of the
device-path may change due to changes in the enumeration of devices.
Therefore it is preferable to use the short-form of device-paths in load
options. Adjust the 'efidebug boot add' command accordingly.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

diff --git a/cmd/efidebug.c b/cmd/efidebug.c
index 401d13c..51e2850 100644 (file)
--- a/cmd/efidebug.c
+++ b/cmd/efidebug.c
@@ -734,20 +734,20 @@ static int do_efi_show_tables(struct cmd_tbl *cmdtp, int flag,
 }
 
 /**
- * create_initrd_dp() - Create a special device for our Boot### option
- *
- * @dev:       Device
- * @part:      Disk partition
- * @file:      Filename
- * Return:     Pointer to the device path or ERR_PTR
+ * create_initrd_dp() - create a special device for our Boot### option
  *
+ * @dev:       device
+ * @part:      disk partition
+ * @file:      filename
+ * @shortform: create short form device path
+ * Return:     pointer to the device path or ERR_PTR
  */
 static
 struct efi_device_path *create_initrd_dp(const char *dev, const char *part,
-                                        const char *file)
+                                        const char *file, int shortform)
 
 {
-       struct efi_device_path *tmp_dp = NULL, *tmp_fp = NULL;
+       struct efi_device_path *tmp_dp = NULL, *tmp_fp = NULL, *short_fp = NULL;
        struct efi_device_path *initrd_dp = NULL;
        efi_status_t ret;
        const struct efi_initrd_dp id_dp = {
@@ -771,9 +771,13 @@ struct efi_device_path *create_initrd_dp(const char *dev, const char *part,
                printf("Cannot create device path for \"%s %s\"\n", part, file);
                goto out;
        }
+       if (shortform)
+               short_fp = efi_dp_shorten(tmp_fp);
+       if (!short_fp)
+               short_fp = tmp_fp;
 
        initrd_dp = efi_dp_append((const struct efi_device_path *)&id_dp,
-                                 tmp_fp);
+                                 short_fp);
 
 out:
        efi_free_pool(tmp_dp);
@@ -807,6 +811,7 @@ static int do_efi_boot_add(struct cmd_tbl *cmdtp, int flag,
        size_t label_len, label_len16;
        u16 *label;
        struct efi_device_path *device_path = NULL, *file_path = NULL;
+       struct efi_device_path *fp_free = NULL;
        struct efi_device_path *final_fp = NULL;
        struct efi_device_path *initrd_dp = NULL;
        struct efi_load_option lo;
@@ -826,7 +831,18 @@ static int do_efi_boot_add(struct cmd_tbl *cmdtp, int flag,
        argc--;
        argv++; /* 'add' */
        for (; argc > 0; argc--, argv++) {
-               if (!strcmp(argv[0], "-b")) {
+               int shortform;
+
+               if (*argv[0] != '-' || strlen(argv[0]) != 2) {
+                               r = CMD_RET_USAGE;
+                               goto out;
+               }
+               shortform = 0;
+               switch (argv[0][1]) {
+               case 'b':
+                       shortform = 1;
+                       /* fallthrough */
+               case 'B':
                        if (argc <  5 || lo.label) {
                                r = CMD_RET_USAGE;
                                goto out;
@@ -849,24 +865,33 @@ static int do_efi_boot_add(struct cmd_tbl *cmdtp, int flag,
 
                        /* file path */
                        ret = efi_dp_from_name(argv[3], argv[4], argv[5],
-                                              &device_path, &file_path);
+                                              &device_path, &fp_free);
                        if (ret != EFI_SUCCESS) {
                                printf("Cannot create device path for \"%s %s\"\n",
                                       argv[3], argv[4]);
                                r = CMD_RET_FAILURE;
                                goto out;
                        }
+                       if (shortform)
+                               file_path = efi_dp_shorten(fp_free);
+                       if (!file_path)
+                               file_path = fp_free;
                        fp_size += efi_dp_size(file_path) +
                                sizeof(struct efi_device_path);
                        argc -= 5;
                        argv += 5;
-               } else if (!strcmp(argv[0], "-i")) {
+                       break;
+               case 'i':
+                       shortform = 1;
+                       /* fallthrough */
+               case 'I':
                        if (argc < 3 || initrd_dp) {
                                r = CMD_RET_USAGE;
                                goto out;
                        }
 
-                       initrd_dp = create_initrd_dp(argv[1], argv[2], argv[3]);
+                       initrd_dp = create_initrd_dp(argv[1], argv[2], argv[3],
+                                                    shortform);
                        if (!initrd_dp) {
                                printf("Cannot add an initrd\n");
                                r = CMD_RET_FAILURE;
@@ -876,7 +901,8 @@ static int do_efi_boot_add(struct cmd_tbl *cmdtp, int flag,
                        argv += 3;
                        fp_size += efi_dp_size(initrd_dp) +
                                sizeof(struct efi_device_path);
-               } else if (!strcmp(argv[0], "-s")) {
+                       break;
+               case 's':
                        if (argc < 1 || lo.optional_data) {
                                r = CMD_RET_USAGE;
                                goto out;
@@ -884,7 +910,8 @@ static int do_efi_boot_add(struct cmd_tbl *cmdtp, int flag,
                        lo.optional_data = (const u8 *)argv[1];
                        argc -= 1;
                        argv += 1;
-               } else {
+                       break;
+               default:
                        r = CMD_RET_USAGE;
                        goto out;
                }
@@ -927,7 +954,7 @@ out:
        efi_free_pool(final_fp);
        efi_free_pool(initrd_dp);
        efi_free_pool(device_path);
-       efi_free_pool(file_path);
+       efi_free_pool(fp_free);
        free(lo.label);
 
        return r;
@@ -1571,12 +1598,11 @@ static int do_efidebug(struct cmd_tbl *cmdtp, int flag,
 static char efidebug_help_text[] =
        "  - UEFI Shell-like interface to configure UEFI environment\n"
        "\n"
-       "efidebug boot add "
-       "-b <bootid> <label> <interface> <devnum>[:<part>] <file path> "
-       "-i <interface> <devnum>[:<part>] <initrd file path> "
-       "-s '<optional data>'\n"
-       "  - set UEFI BootXXXX variable\n"
-       "    <load options> will be passed to UEFI application\n"
+       "efidebug boot add - set UEFI BootXXXX variable\n"
+       "  -b|-B <bootid> <label> <interface> <devnum>[:<part>] <file path>\n"
+       "  -i|-I <interface> <devnum>[:<part>] <initrd file path>\n"
+       "  (-b, -i for short form device path)\n"
+       "  -s '<optional data>'\n"
        "efidebug boot rm <bootid#1> [<bootid#2> [<bootid#3> [...]]]\n"
        "  - delete UEFI BootXXXX variables\n"
        "efidebug boot dump\n"