kike: resolve the path to PID files better

common.c

@@ -90,6 +90,49 @@ strncasecmp_ascii (const char *a, const char *b, size_t n)
 	return 0;
 }
 
+static char *
+resolve_relative_runtime_filename (const char *filename)
+{
+	struct str path;
+	str_init (&path);
+
+	const char *runtime_dir = getenv ("XDG_RUNTIME_DIR");
+	if (runtime_dir && *runtime_dir == '/')
+		str_append (&path, runtime_dir);
+	else
+		get_xdg_home_dir (&path, "XDG_DATA_HOME", ".local/share");
+	str_append_printf (&path, "/%s/%s", PROGRAM_NAME, filename);
+
+	// Try to create the file's ancestors
+	const char *last_slash = strrchr (path.str, '/');
+	if (last_slash && last_slash != path.str)
+	{
+		char *copy = xstrndup (path.str, last_slash - path.str);
+		(void) mkdir_with_parents (copy, NULL);
+		free (copy);
+	}
+	return str_steal (&path);
+}
+
+static char *
+resolve_filename (const char *filename, char *(*relative_cb) (const char *))
+{
+	// Absolute path is absolute
+	if (*filename == '/')
+		return xstrdup (filename);
+
+	// We don't want to use wordexp() for this as it may execute /bin/sh
+	if (*filename == '~')
+	{
+		// Paths to home directories ought to be absolute
+		char *expanded = try_expand_tilde (filename + 1);
+		if (expanded)
+			return expanded;
+		print_debug ("failed to expand the home directory in `%s'", filename);
+	}
+	return relative_cb (filename);
+}
+
 // --- Logging -----------------------------------------------------------------
 
 static void