repart: deal with empty partition label sensibly

libfdisk appears to return NULL when encountering an empty partition
label, let's handle this sanely, and treat NULL and "" for the current
label as the same, but for the new label as distinct: there NULL means
nothing is set, and "" means an actual empty label.

diff --git a/src/partition/repart.c b/src/partition/repart.c
index 351b3d1b5e959bda44126b62f9ff44b269df6de1..0db8d4aba12d2d6076ad381fc94806eea1d9fc0a 100644 (file)
--- a/src/partition/repart.c
+++ b/src/partition/repart.c
@@ -963,6 +963,9 @@ static int config_parse_label(
         assert(rvalue);
         assert(label);
 
+        /* Nota bene: the empty label is a totally valid one. Let's hence not follow our usual rule of
+         * assigning the empty string to reset to default here, but really accept it as label to set. */
+
         r = specifier_printf(rvalue, specifier_table, NULL, &resolved);
         if (r < 0) {
                 log_syntax(unit, LOG_WARNING, filename, line, r,
@@ -1873,7 +1876,7 @@ static int context_dump_partitions(Context *context, const char *node) {
                 r = table_add_many(
                                 t,
                                 TABLE_STRING, gpt_partition_type_uuid_to_string_harder(p->type_uuid, uuid_buffer),
-                                TABLE_STRING, label ?: "-", TABLE_SET_COLOR, label ? NULL : ansi_grey(),
+                                TABLE_STRING, empty_to_null(label) ?: "-", TABLE_SET_COLOR, empty_to_null(label) ? NULL : ansi_grey(),
                                 TABLE_UUID, sd_id128_is_null(p->new_uuid) ? p->current_uuid : p->new_uuid,
                                 TABLE_STRING, p->definition_path ? basename(p->definition_path) : "-", TABLE_SET_COLOR, p->definition_path ? NULL : ansi_grey(),
                                 TABLE_STRING, partname ?: "-", TABLE_SET_COLOR, partname ? NULL : ansi_highlight(),
@@ -2444,7 +2447,7 @@ static int partition_encrypt(
                          volume_key,
                          volume_key_size,
                          &(struct crypt_params_luks2) {
-                                 .label = p->new_label,
+                                 .label = strempty(p->new_label),
                                  .sector_size = 512U,
                          });
         if (r < 0)
@@ -2838,7 +2841,7 @@ static int context_mkfs(Context *context) {
                 if (r < 0)
                         return r;
 
-                r = make_filesystem(fsdev, p->format, p->new_label, fs_uuid, arg_discard);
+                r = make_filesystem(fsdev, p->format, strempty(p->new_label), fs_uuid, arg_discard);
                 if (r < 0) {
                         encrypted_dev_fd = safe_close(encrypted_dev_fd);
                         (void) deactivate_luks(cd, encrypted);
@@ -3025,7 +3028,7 @@ static int context_acquire_partition_uuids_and_labels(Context *context) {
 
                         if (p->current_label) {
                                 free(p->new_label);
-                                p->new_label = strdup(p->current_label);
+                                p->new_label = strdup(strempty(p->current_label));
                                 if (!p->new_label)
                                         return log_oom();
                         }
@@ -3108,9 +3111,7 @@ static int context_mangle_partitions(Context *context) {
                         }
 
                         if (!streq_ptr(p->new_label, p->current_label)) {
-                                assert(!isempty(p->new_label));
-
-                                r = fdisk_partition_set_name(p->current_partition, p->new_label);
+                                r = fdisk_partition_set_name(p->current_partition, strempty(p->new_label));
                                 if (r < 0)
                                         return log_error_errno(r, "Failed to set partition label: %m");
 
@@ -3134,7 +3135,7 @@ static int context_mangle_partitions(Context *context) {
                         assert(p->offset % 512 == 0);
                         assert(p->new_size % 512 == 0);
                         assert(!sd_id128_is_null(p->new_uuid));
-                        assert(!isempty(p->new_label));
+                        assert(p->new_label);
 
                         t = fdisk_new_parttype();
                         if (!t)
@@ -3172,7 +3173,7 @@ static int context_mangle_partitions(Context *context) {
                         if (r < 0)
                                 return log_error_errno(r, "Failed to set partition UUID: %m");
 
-                        r = fdisk_partition_set_name(q, p->new_label);
+                        r = fdisk_partition_set_name(q, strempty(p->new_label));
                         if (r < 0)
                                 return log_error_errno(r, "Failed to set partition label: %m");