util: split out kbd related stuff

This stuff is neither generic enough to be in def.h, nor really has much
to do with locale, hence give it its own .c/.h file pair.

src/basic/kbd-util.c

@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <ftw.h>
+
+#include "kbd-util.h"
+#include "log.h"
+#include "path-util.h"
+#include "set.h"
+#include "string-util.h"
+#include "strv.h"
+#include "utf8.h"
+
+static thread_local Set *keymaps = NULL;
+
+static int nftw_cb(
+                const char *fpath,
+                const struct stat *sb,
+                int tflag,
+                struct FTW *ftwbuf) {
+
+        _cleanup_free_ char *p = NULL;
+        char *e;
+        int r;
+
+        if (tflag != FTW_F)
+                return 0;
+
+        if (!endswith(fpath, ".map") &&
+            !endswith(fpath, ".map.gz"))
+                return 0;
+
+        p = strdup(basename(fpath));
+        if (!p)
+                return FTW_STOP;
+
+        e = endswith(p, ".map");
+        if (e)
+                *e = 0;
+
+        e = endswith(p, ".map.gz");
+        if (e)
+                *e = 0;
+
+        if (!keymap_is_valid(p))
+                return 0;
+
+        r = set_consume(keymaps, TAKE_PTR(p));
+        if (r < 0 && r != -EEXIST)
+                return r;
+
+        return 0;
+}
+
+int get_keymaps(char ***ret) {
+        _cleanup_strv_free_ char **l = NULL;
+        const char *dir;
+        int r;
+
+        keymaps = set_new(&string_hash_ops);
+        if (!keymaps)
+                return -ENOMEM;
+
+        NULSTR_FOREACH(dir, KBD_KEYMAP_DIRS) {
+                r = nftw(dir, nftw_cb, 20, FTW_PHYS|FTW_ACTIONRETVAL);
+
+                if (r == FTW_STOP)
+                        log_debug("Directory not found %s", dir);
+                else if (r < 0)
+                        log_debug_errno(r, "Can't add keymap: %m");
+        }
+
+        l = set_get_strv(keymaps);
+        if (!l) {
+                set_free_free(keymaps);
+                return -ENOMEM;
+        }
+
+        set_free(keymaps);
+
+        if (strv_isempty(l))
+                return -ENOENT;
+
+        strv_sort(l);
+
+        *ret = TAKE_PTR(l);
+
+        return 0;
+}
+
+bool keymap_is_valid(const char *name) {
+
+        if (isempty(name))
+                return false;
+
+        if (strlen(name) >= 128)
+                return false;
+
+        if (!utf8_is_valid(name))
+                return false;
+
+        if (!filename_is_valid(name))
+                return false;
+
+        if (!string_is_safe(name))
+                return false;
+
+        return true;
+}