+int get_files_in_directory(const char *path, char ***list) {
+ DIR *d;
+ int r = 0;
+ unsigned n = 0;
+ char **l = NULL;
+
+ assert(path);
+
+ /* Returns all files in a directory in *list, and the number
+ * of files as return value. If list is NULL returns only the
+ * number */
+
+ d = opendir(path);
+ for (;;) {
+ struct dirent buffer, *de;
+ int k;
+
+ k = readdir_r(d, &buffer, &de);
+ if (k != 0) {
+ r = -k;
+ goto finish;
+ }
+
+ if (!de)
+ break;
+
+ dirent_ensure_type(d, de);
+
+ if (!dirent_is_file(de))
+ continue;
+
+ if (list) {
+ if ((unsigned) r >= n) {
+ char **t;
+
+ n = MAX(16, 2*r);
+ t = realloc(l, sizeof(char*) * n);
+ if (!t) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ l = t;
+ }
+
+ assert((unsigned) r < n);
+
+ l[r] = strdup(de->d_name);
+ if (!l[r]) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ l[++r] = NULL;
+ } else
+ r++;
+ }
+
+finish:
+ if (d)
+ closedir(d);
+
+ if (r >= 0) {
+ if (list)
+ *list = l;
+ } else
+ strv_free(l);
+
+ return r;
+}
+
+char *join(const char *x, ...) {
+ va_list ap;
+ size_t l;
+ char *r, *p;
+
+ va_start(ap, x);
+
+ if (x) {
+ l = strlen(x);
+
+ for (;;) {
+ const char *t;
+
+ t = va_arg(ap, const char *);
+ if (!t)
+ break;
+
+ l += strlen(t);
+ }
+ } else
+ l = 0;
+
+ va_end(ap);
+
+ r = new(char, l+1);
+ if (!r)
+ return NULL;
+
+ if (x) {
+ p = stpcpy(r, x);
+
+ va_start(ap, x);
+
+ for (;;) {
+ const char *t;
+
+ t = va_arg(ap, const char *);
+ if (!t)
+ break;
+
+ p = stpcpy(p, t);
+ }
+ } else
+ r[0] = 0;
+
+ return r;
+}
+
+bool is_main_thread(void) {
+ static __thread int cached = 0;
+
+ if (_unlikely_(cached == 0))
+ cached = getpid() == gettid() ? 1 : -1;
+
+ return cached > 0;
+}
+