shared: move storage-util to libshared

The storage backend providers (block, fs) and storagectl currently each
extract storage-util.c into their target. Several upcoming consumers
(machine-util's BindVolume parser, vmspawn's hotplug glue, machinectl's
new bind-volume verbs) need the StorageProvider type/string-table
helpers and a future shared Acquire client helper.

Move storage-util.{c,h} to src/shared so libshared exports the symbols
once and every consumer (storage providers, storagectl, libshared
itself) picks them up by linking libshared. Drop the now-redundant
'extract'/'objects' wiring in src/storage/meson.build.

No code changes; this is purely a relocation.

Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

src/shared/meson.build

@@ -199,6 +199,7 @@ shared_sources = files(
         'socket-netlink.c',
         'specifier.c',
         'ssl-util.c',
+        'storage-util.c',
         'switch-root.c',
         'swtpm-util.c',
         'tar-util.c',

src/shared/storage-util.c

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "json-util.h"
+#include "string-table.h"
+#include "storage-util.h"
+
+static const char *volume_type_table[_VOLUME_TYPE_MAX] = {
+        [VOLUME_BLK] = "blk",
+        [VOLUME_REG] = "reg",
+        [VOLUME_DIR] = "dir",
+};
+
+static const char *create_mode_table[_CREATE_MODE_MAX] = {
+        [CREATE_ANY]  = "any",
+        [CREATE_NEW]  = "new",
+        [CREATE_OPEN] = "open",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(volume_type, VolumeType);
+DEFINE_STRING_TABLE_LOOKUP(create_mode, CreateMode);
+
+JSON_DISPATCH_ENUM_DEFINE(json_dispatch_volume_type, VolumeType, volume_type_from_string);
+JSON_DISPATCH_ENUM_DEFINE(json_dispatch_create_mode, CreateMode, create_mode_from_string);

src/shared/storage-util.h

@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-json.h"
+
+#include "string-table-fundamental.h"
+#include "string-util.h"
+
+/* This closely follows the kernel's inode type naming, i.e. is supposed to be a subset of what
+ * inode_type_from_string() parses. */
+typedef enum VolumeType {
+        VOLUME_BLK,
+        VOLUME_REG,
+        VOLUME_DIR,
+        _VOLUME_TYPE_MAX,
+        _VOLUME_TYPE_INVALID = -EINVAL,
+} VolumeType;
+
+typedef enum CreateMode {
+        CREATE_ANY,
+        CREATE_NEW,
+        CREATE_OPEN,
+        _CREATE_MODE_MAX,
+        _CREATE_MODE_INVALID = -EINVAL,
+} CreateMode;
+
+DECLARE_STRING_TABLE_LOOKUP(volume_type, VolumeType);
+DECLARE_STRING_TABLE_LOOKUP(create_mode, CreateMode);
+
+int json_dispatch_volume_type(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
+int json_dispatch_create_mode(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
+
+static inline bool storage_volume_name_is_valid(const char *n) {
+        return string_is_safe(n, /* flags= */ 0);
+}
+
+static inline bool storage_template_name_is_valid(const char *n) {
+        return string_is_safe(n, /* flags= */ 0);
+}
+
+static inline bool storage_provider_name_is_valid(const char *n) {
+        return string_is_safe(n, STRING_FILENAME);
+}