config: support merging multiple config files

Add the -m|--merge-config command line option to iterate backwards over
XDG Base Dir paths and read config/theme files multiple times.

For example if both ~/.config/labwc/rc.xml and /etc/xdg/labwc/rc.xml
exist, the latter will be read first and then the former (if
--merge-config is enabled).

When $XDG_CONFIG_HOME is defined, make it replace (not augment)
$HOME/.config. Similarly, make $XDG_CONFIG_DIRS replace /etc/xdg when
defined.

XDG Base Dir Spec does not specify whether or not an application (or a
compositor!) should (a) define that only the file under the most important
base directory should be used, or (b) define rules for merging the
information from the different files.

ref: https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html

In the case of labwc there is a use-case for both positions, just to be
clear, the default behaviour, described by position (a) above, does NOT
change.

This change affects the following config/theme files:
  - rc.xml
  - menu.xml
  - autostart
  - environment
  - themerc
  - themerc-override
  - Theme buttons, for example max.xbm

Instead of caching global config/theme directories, create lists of paths
(e.g.  '/home/foo/.config/labwc/rc.xml', '/etc/xdg/labwc/rc.xml', etc).
This creates more common parsing logic and just reversing the direction
of iteration and breaks early if config-merge is not wanted.

Enable better fallback for themes. For example if a particular theme does
not exist in $HOME/.local/share/themes, it will be searched for in
~/.themes/ and so on. This also applies to theme buttons which now
fallback on an individual basis.

Avoid using stat() in most situations and just go straight to fopen().

Fixes #1406

docs/labwc-config.5.scd

@@ -18,6 +18,19 @@ searched for in the following order:
 - ${XDG_CONFIG_HOME:-$HOME/.config}/labwc
 - ${XDG_CONFIG_DIRS:-/etc/xdg}/labwc
 
+When $XDG_CONFIG_HOME is defined, it replaces (rather than augments)
+$HOME/.config. The same is the case for $XDG_CONFIG_DIRS and /etc/xdg.
+
+The XDG Base Directory Specification does not specify whether or not programs
+should (a) allow the first-identified configuration file to supersede any
+others, or (b) define rules for merging the information from more than one file.
+
+By default, labwc uses option (a), reading only the first file identified.  With
+the --merge-config option, the search order is reserved, but every configuration
+file encountered is processed in turn. Thus, user-specific files will augment
+system-wide configurations, with conflicts favoring the user-specific
+alternative.
+
 The configuration directory location can be override with the -C command line
 option.
 

docs/labwc-theme.5.scd

@@ -15,6 +15,9 @@ searched for in the following order:
 - /usr/local/share/themes/<theme-name>/openbox-3/
 - /opt/share/themes/<theme-name>/openbox-3/
 
+When $XDG_DATA_HOME is defined, it replaces (rather than augments)
+$HOME/.local/share. The same is the case for $XDG_DATA_DIRS and /usr/share/.
+
 Choosing a theme is done by editing the <name> key in the <theme> section of
 the rc.xml configuration file (labwc-config(5)).
 

docs/labwc.1.scd

@@ -45,6 +45,9 @@ the `--exit` and `--reconfigure` options use.
 *-h, --help*
 	Show help message and quit
 
+*-m, --merge-config*
+	Merge user config/theme files in all XDG Base Directories
+
 *-r, --reconfigure*
 	Reload the compositor configuration
 

include/common/dir.h

@@ -2,12 +2,19 @@
 #ifndef LABWC_DIR_H
 #define LABWC_DIR_H
 
-char *config_dir(void);
+#include <wayland-server-core.h>
 
-/**
+struct path {
- * theme_dir - find theme directory containing theme @theme_name
+	char *string;
- * @theme_name: theme to search for
+	struct wl_list link;
- */
+};
-char *theme_dir(const char *theme_name);
+
+struct wl_list *paths_get_prev(struct wl_list *elm);
+struct wl_list *paths_get_next(struct wl_list *elm);
+
+void paths_config_create(struct wl_list *paths, const char *filename);
+void paths_theme_create(struct wl_list *paths, const char *theme_name,
+	const char *filename);
+void paths_destroy(struct wl_list *paths);
 
 #endif /* LABWC_DIR_H */

include/config/rcxml.h

@@ -48,6 +48,7 @@ struct window_switcher_field {
 
 struct rcxml {
 	char *config_dir;
+	bool merge_config;
 
 	/* core */
 	bool xdg_shell_server_side_deco;

include/config/session.h

@@ -4,17 +4,15 @@
 
 /**
  * session_environment_init - set enrivonment variables based on <key>=<value>
- * @dir: path to config directory
  * pairs in `${XDG_CONFIG_DIRS:-/etc/xdg}/lawbc/environment` with user override
  * in `${XDG_CONFIG_HOME:-$HOME/.config}`
  */
-void session_environment_init(const char *dir);
+void session_environment_init(void);
 
 /**
  * session_autostart_init - run autostart file as shell script
- * @dir: path to config directory
  * Note: Same as `sh ~/.config/labwc/autostart` (or equivalent XDG config dir)
  */
-void session_autostart_init(const char *dir);
+void session_autostart_init(void);
 
 #endif /* LABWC_SESSION_H */

src/button/common.c

@@ -1,11 +1,27 @@
 // SPDX-License-Identifier: GPL-2.0-only
 #include <stdio.h>
+#include <unistd.h>
 #include "button/common.h"
 #include "common/dir.h"
 #include "config/rcxml.h"
+#include "labwc.h"
 
 void
 button_filename(const char *name, char *buf, size_t len)
 {
-	snprintf(buf, len, "%s/%s", theme_dir(rc.theme_name), name);
+	struct wl_list paths;
+	paths_theme_create(&paths, rc.theme_name, name);
+
+	/*
+	 * You can't really merge buttons, so let's just iterate forwards
+	 * and stop on the first hit
+	 */
+	struct path *path;
+	wl_list_for_each(path, &paths, link) {
+		if (access(path->string, R_OK) == 0) {
+			snprintf(buf, len, "%s", path->string);
+			break;
+		}
+	}
+	paths_destroy(&paths);
 }

src/common/dir.c

@@ -4,143 +4,190 @@
  *
  * Copyright Johan Malm 2020
  */
-
+#include <assert.h>
 #include <glib.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/stat.h>
 #include "common/dir.h"
+#include "common/buf.h"
+#include "common/list.h"
+#include "common/mem.h"
+#include "common/string-helpers.h"
+#include "labwc.h"
 
 struct dir {
 	const char *prefix;
+	const char *default_prefix;
 	const char *path;
 };
 
 static struct dir config_dirs[] = {
-	{ "XDG_CONFIG_HOME", "labwc" },
+	{
-	{ "HOME", ".config/labwc" },
+		.prefix = "XDG_CONFIG_HOME",
-	{ "XDG_CONFIG_DIRS", "labwc" },
+		.default_prefix = "$HOME/.config",
-	{ NULL, "/etc/xdg/labwc" },
+		.path = "labwc"
-	{ NULL, NULL }
+	}, {
+		.prefix = "XDG_CONFIG_DIRS",
+		.default_prefix = "/etc/xdg",
+		.path = "labwc",
+	}, {
+		.path = NULL,
+	}
 };
 
 static struct dir theme_dirs[] = {
-	{ "XDG_DATA_HOME", "themes" },
+	{
-	{ "HOME", ".local/share/themes" },
+		.prefix = "XDG_DATA_HOME",
-	{ "HOME", ".themes" },
+		.default_prefix = "$HOME/.local/share",
-	{ "XDG_DATA_DIRS", "themes" },
+		.path = "themes",
-	{ NULL, "/usr/share/themes" },
+	}, {
-	{ NULL, "/usr/local/share/themes" },
+		.prefix = "HOME",
-	{ NULL, "/opt/share/themes" },
+		.path = ".themes",
-	{ NULL, NULL }
+	}, {
+		.prefix = "XDG_DATA_DIRS",
+		.default_prefix = "/usr/share:/usr/local/share:/opt/share",
+		.path = "themes",
+	}, {
+		.path = NULL,
+	}
 };
 
-static bool
-isdir(const char *path)
-{
-	struct stat st;
-	return (!stat(path, &st) && S_ISDIR(st.st_mode));
-}
-
 struct ctx {
 	void (*build_path_fn)(struct ctx *ctx, char *prefix, const char *path);
+	const char *filename;
 	char *buf;
 	size_t len;
 	struct dir *dirs;
 	const char *theme_name;
+	struct wl_list *list;
 };
 
+struct wl_list *paths_get_prev(struct wl_list *elm) { return elm->prev; }
+struct wl_list *paths_get_next(struct wl_list *elm) { return elm->next; }
+
 static void
 build_config_path(struct ctx *ctx, char *prefix, const char *path)
 {
-	if (!prefix) {
+	assert(prefix);
-		snprintf(ctx->buf, ctx->len, "%s", path);
+	snprintf(ctx->buf, ctx->len, "%s/%s/%s", prefix, path, ctx->filename);
-	} else {
-		snprintf(ctx->buf, ctx->len, "%s/%s", prefix, path);
-	}
 }
 
 static void
 build_theme_path(struct ctx *ctx, char *prefix, const char *path)
 {
-	if (!prefix) {
+	assert(prefix);
-		snprintf(ctx->buf, ctx->len, "%s/%s/openbox-3", path,
+	snprintf(ctx->buf, ctx->len, "%s/%s/%s/openbox-3/%s", prefix, path,
-			ctx->theme_name);
+		ctx->theme_name, ctx->filename);
-	} else {
-		snprintf(ctx->buf, ctx->len, "%s/%s/%s/openbox-3", prefix, path,
-			ctx->theme_name);
-	}
 }
 
-static char *
+static void
 find_dir(struct ctx *ctx)
 {
 	char *debug = getenv("LABWC_DEBUG_DIR_CONFIG_AND_THEME");
 
 	for (int i = 0; ctx->dirs[i].path; i++) {
 		struct dir d = ctx->dirs[i];
-		if (!d.prefix) {
+		struct buf prefix;
-			/* handle /etc/xdg... */
+		buf_init(&prefix);
-			ctx->build_path_fn(ctx, NULL, d.path);
+
+		/*
+		 * Replace (rather than augment) $HOME/.config with
+		 * $XDG_CONFIG_HOME if defined, and so on for the other
+		 * XDG Base Directories.
+		 */
+		char *pfxenv = getenv(d.prefix);
+		buf_add(&prefix, pfxenv ? pfxenv : d.default_prefix);
+		if (!prefix.len) {
+			free(prefix.buf);
+			continue;
+		}
+
+		/* Handle .default_prefix shell variables such as $HOME */
+		buf_expand_shell_variables(&prefix);
+
+		/*
+		 * Respect that $XDG_DATA_DIRS can contain multiple colon
+		 * separated paths and that we have structured the
+		 * .default_prefix in the same way.
+		 */
+		gchar * *prefixes;
+		prefixes = g_strsplit(prefix.buf, ":", -1);
+		for (gchar * *p = prefixes; *p; p++) {
+			ctx->build_path_fn(ctx, *p, d.path);
 			if (debug) {
 				fprintf(stderr, "%s\n", ctx->buf);
 			}
-			if (isdir(ctx->buf)) {
+
-				return ctx->buf;
+			/*
-			}
+			 * TODO: We could stat() and continue here if we really
-		} else {
+			 * wanted to only respect only the first hit, but feels
-			/* handle $HOME/.config/... and $XDG_* */
+			 * like it is probably overkill.
-			char *prefix = getenv(d.prefix);
+			 */
-			if (!prefix) {
+			struct path *path = znew(*path);
-				continue;
+			path->string = xstrdup(ctx->buf);
-			}
+			wl_list_append(ctx->list, &path->link);
-			gchar * *prefixes;
-			prefixes = g_strsplit(prefix, ":", -1);
-			for (gchar * *p = prefixes; *p; p++) {
-				ctx->build_path_fn(ctx, *p, d.path);
-				if (debug) {
-					fprintf(stderr, "%s\n", ctx->buf);
-				}
-				if (isdir(ctx->buf)) {
-					g_strfreev(prefixes);
-					return ctx->buf;
-				}
-			}
-			g_strfreev(prefixes);
 		}
+		g_strfreev(prefixes);
+		free(prefix.buf);
 	}
-	/* no directory was found */
-	ctx->buf[0] = '\0';
-	return ctx->buf;
 }
 
-char *
+void
-config_dir(void)
+paths_config_create(struct wl_list *paths, const char *filename)
 {
-	static char buf[4096] = { 0 };
+	char buf[4096] = { 0 };
-	if (buf[0] != '\0') {
+	wl_list_init(paths);
-		return buf;
+
+	/*
+	 * If user provided a config directory with the -C command line option,
+	 * then that trumps everything else and we do not create the
+	 * XDG-Base-Dir list.
+	 */
+	if (rc.config_dir) {
+		struct path *path = znew(*path);
+		path->string = strdup_printf("%s/%s", rc.config_dir, filename);
+		wl_list_append(paths, &path->link);
+		return;
 	}
+
 	struct ctx ctx = {
 		.build_path_fn = build_config_path,
+		.filename = filename,
 		.buf = buf,
 		.len = sizeof(buf),
-		.dirs = config_dirs
+		.dirs = config_dirs,
+		.list = paths,
 	};
-	return find_dir(&ctx);
+	find_dir(&ctx);
 }
 
-char *
+void
-theme_dir(const char *theme_name)
+paths_theme_create(struct wl_list *paths, const char *theme_name,
+		const char *filename)
 {
 	static char buf[4096] = { 0 };
+	wl_list_init(paths);
 	struct ctx ctx = {
 		.build_path_fn = build_theme_path,
+		.filename = filename,
 		.buf = buf,
 		.len = sizeof(buf),
 		.dirs = theme_dirs,
-		.theme_name = theme_name
+		.theme_name = theme_name,
+		.list = paths,
 	};
-	return find_dir(&ctx);
+	find_dir(&ctx);
+}
+
+void
+paths_destroy(struct wl_list *paths)
+{
+	struct path *path, *next;
+	wl_list_for_each_safe(path, next, paths, link) {
+		free(path->string);
+		wl_list_remove(&path->link);
+		free(path);
+	}
 }

src/config/rcxml.c

@@ -14,6 +14,7 @@
 #include <wlr/util/box.h>
 #include <wlr/util/log.h>
 #include "action.h"
+#include "common/dir.h"
 #include "common/list.h"
 #include "common/macros.h"
 #include "common/mem.h"
@@ -1473,69 +1474,68 @@ validate(void)
 	validate_actions();
 }
 
-static void
-rcxml_path(char *buf, size_t len)
-{
-	if (!rc.config_dir) {
-		return;
-	}
-	snprintf(buf, len, "%s/rc.xml", rc.config_dir);
-}
-
-static void
-find_config_file(char *buffer, size_t len, const char *filename)
-{
-	if (filename) {
-		snprintf(buffer, len, "%s", filename);
-		return;
-	}
-	rcxml_path(buffer, len);
-}
-
 void
 rcxml_read(const char *filename)
 {
-	FILE *stream;
-	char *line = NULL;
-	size_t len = 0;
-	struct buf b;
-	static char rcxml[4096] = {0};
-
 	rcxml_init();
 
-	/*
+	struct wl_list paths;
-	 * rcxml_read() can be called multiple times, but we only set rcxml[]
+
-	 * the first time. The specified 'filename' is only respected the first
+	if (filename) {
-	 * time.
+		/* Honour command line argument -c <filename> */
-	 */
+		wl_list_init(&paths);
-	if (rcxml[0] == '\0') {
+		struct path *path = znew(*path);
-		find_config_file(rcxml, sizeof(rcxml), filename);
+		path->string = xstrdup(filename);
-	}
+		wl_list_append(&paths, &path->link);
-	if (rcxml[0] == '\0') {
+	} else {
-		wlr_log(WLR_INFO, "cannot find rc.xml config file");
+		paths_config_create(&paths, "rc.xml");
-		goto no_config;
 	}
 
 	/* Reading file into buffer before parsing - better for unit tests */
-	stream = fopen(rcxml, "r");
+	struct buf b;
-	if (!stream) {
+
-		wlr_log(WLR_ERROR, "cannot read (%s)", rcxml);
+	bool should_merge_config = rc.merge_config;
-		goto no_config;
+	struct wl_list *(*iter)(struct wl_list *list);
-	}
+	iter = should_merge_config ? paths_get_prev : paths_get_next;
-	wlr_log(WLR_INFO, "read config file %s", rcxml);
+
-	buf_init(&b);
+	/*
-	while (getline(&line, &len, stream) != -1) {
+	 * This is the equivalent of a wl_list_for_each() which optionally
-		char *p = strrchr(line, '\n');
+	 * iterates in reverse depending on 'should_merge_config'
-		if (p) {
+	 *
-			*p = '\0';
+	 * If not merging, we iterate forwards and break after the first
+	 * iteration.
+	 *
+	 * If merging, we iterate backwards (least important XDG Base Dir first)
+	 * and keep going.
+	 */
+	for (struct wl_list *elm = iter(&paths); elm != &paths; elm = iter(elm)) {
+		struct path *path = wl_container_of(elm, path, link);
+		FILE *stream = fopen(path->string, "r");
+		if (!stream) {
+			continue;
 		}
-		buf_add(&b, line);
+
-	}
+		wlr_log(WLR_INFO, "read config file %s", path->string);
-	free(line);
+
-	fclose(stream);
+		buf_init(&b);
-	rcxml_parse_xml(&b);
+		char *line = NULL;
-	free(b.buf);
+		size_t len = 0;
-no_config:
+		while (getline(&line, &len, stream) != -1) {
+			char *p = strrchr(line, '\n');
+			if (p) {
+				*p = '\0';
+			}
+			buf_add(&b, line);
+		}
+		zfree(line);
+		fclose(stream);
+		rcxml_parse_xml(&b);
+		zfree(b.buf);
+		if (!should_merge_config) {
+			break;
+		}
+	};
+	paths_destroy(&paths);
 	post_processing();
 	validate();
 }

src/config/session.c

@@ -7,10 +7,12 @@
 #include <sys/stat.h>
 #include <wlr/util/log.h>
 #include "common/buf.h"
+#include "common/dir.h"
 #include "common/file-helpers.h"
 #include "common/spawn.h"
 #include "common/string-helpers.h"
 #include "config/session.h"
+#include "labwc.h"
 
 static bool
 string_empty(const char *s)
@@ -45,14 +47,15 @@ error:
 	free(value.buf);
 }
 
-static void
+/* return true on successful read */
+static bool
 read_environment_file(const char *filename)
 {
 	char *line = NULL;
 	size_t len = 0;
 	FILE *stream = fopen(filename, "r");
 	if (!stream) {
-		return;
+		return false;
 	}
 	wlr_log(WLR_INFO, "read environment file %s", filename);
 	while (getline(&line, &len, stream) != -1) {
@@ -64,15 +67,7 @@ read_environment_file(const char *filename)
 	}
 	free(line);
 	fclose(stream);
-}
+	return true;
-
-static char *
-build_path(const char *dir, const char *filename)
-{
-	if (string_empty(dir) || string_empty(filename)) {
-		return NULL;
-	}
-	return strdup_printf("%s/%s", dir, filename);
 }
 
 static void
@@ -96,7 +91,7 @@ update_activation_env(const char *env_keys)
 }
 
 void
-session_environment_init(const char *dir)
+session_environment_init(void)
 {
 	/*
 	 * Set default for XDG_CURRENT_DESKTOP so xdg-desktop-portal-wlr is happy.
@@ -114,32 +109,49 @@ session_environment_init(const char *dir)
 	 */
 	setenv("_JAVA_AWT_WM_NONREPARENTING", "1", 0);
 
-	char *environment = build_path(dir, "environment");
+	struct wl_list paths;
-	if (!environment) {
+	paths_config_create(&paths, "environment");
-		return;
+
+	bool should_merge_config = rc.merge_config;
+	struct wl_list *(*iter)(struct wl_list *list);
+	iter = should_merge_config ? paths_get_prev : paths_get_next;
+
+	for (struct wl_list *elm = iter(&paths); elm != &paths; elm = iter(elm)) {
+		struct path *path = wl_container_of(elm, path, link);
+		bool success = read_environment_file(path->string);
+		if (success && !should_merge_config) {
+			break;
+		}
 	}
-	read_environment_file(environment);
+	paths_destroy(&paths);
-	free(environment);
 }
 
 void
-session_autostart_init(const char *dir)
+session_autostart_init(void)
 {
 	/* Update dbus and systemd user environment, each may fail gracefully */
 	update_activation_env("DISPLAY WAYLAND_DISPLAY XDG_CURRENT_DESKTOP");
 
-	char *autostart = build_path(dir, "autostart");
+	struct wl_list paths;
-	if (!autostart) {
+	paths_config_create(&paths, "autostart");
-		return;
+
+	bool should_merge_config = rc.merge_config;
+	struct wl_list *(*iter)(struct wl_list *list);
+	iter = should_merge_config ? paths_get_prev : paths_get_next;
+
+	for (struct wl_list *elm = iter(&paths); elm != &paths; elm = iter(elm)) {
+		struct path *path = wl_container_of(elm, path, link);
+		if (!file_exists(path->string)) {
+			continue;
+		}
+		wlr_log(WLR_INFO, "run autostart file %s", path->string);
+		char *cmd = strdup_printf("sh %s", path->string);
+		spawn_async_no_shell(cmd);
+		free(cmd);
+
+		if (!should_merge_config) {
+			break;
+		}
 	}
-	if (!file_exists(autostart)) {
+	paths_destroy(&paths);
-		wlr_log(WLR_ERROR, "no autostart file");
-		goto out;
-	}
-	wlr_log(WLR_INFO, "run autostart file %s", autostart);
-	char *cmd = strdup_printf("sh %s", autostart);
-	spawn_async_no_shell(cmd);
-	free(cmd);
-out:
-	free(autostart);
 }

src/main.c

@@ -21,6 +21,7 @@ static const struct option long_options[] = {
 	{"debug", no_argument, NULL, 'd'},
 	{"exit", no_argument, NULL, 'e'},
 	{"help", no_argument, NULL, 'h'},
+	{"merge-config", no_argument, NULL, 'm'},
 	{"reconfigure", no_argument, NULL, 'r'},
 	{"startup", required_argument, NULL, 's'},
 	{"version", no_argument, NULL, 'v'},
@@ -35,6 +36,7 @@ static const char labwc_usage[] =
 "  -d, --debug              Enable full logging, including debug information\n"
 "  -e, --exit               Exit the compositor\n"
 "  -h, --help               Show help message and quit\n"
+"  -m, --merge-config       Merge user config files/theme in all XDG Base Dirs\n"
 "  -r, --reconfigure        Reload the compositor configuration\n"
 "  -s, --startup <command>  Run command on startup\n"
 "  -v, --version            Show version number and quit\n"
@@ -91,7 +93,7 @@ main(int argc, char *argv[])
 	int c;
 	while (1) {
 		int index = 0;
-		c = getopt_long(argc, argv, "c:C:dehrs:vV", long_options, &index);
+		c = getopt_long(argc, argv, "c:C:dehmrs:vV", long_options, &index);
 		if (c == -1) {
 			break;
 		}
@@ -100,7 +102,7 @@ main(int argc, char *argv[])
 			config_file = optarg;
 			break;
 		case 'C':
-			rc.config_dir = xstrdup(optarg);
+			rc.config_dir = optarg;
 			break;
 		case 'd':
 			verbosity = WLR_DEBUG;
@@ -108,6 +110,9 @@ main(int argc, char *argv[])
 		case 'e':
 			send_signal_to_labwc_pid(SIGTERM);
 			exit(0);
+		case 'm':
+			rc.merge_config = true;
+			break;
 		case 'r':
 			send_signal_to_labwc_pid(SIGHUP);
 			exit(0);
@@ -133,11 +138,7 @@ main(int argc, char *argv[])
 
 	die_on_detecting_suid();
 
-	if (!rc.config_dir) {
+	session_environment_init();
-		rc.config_dir = config_dir();
-	}
-	wlr_log(WLR_INFO, "using config dir (%s)\n", rc.config_dir);
-	session_environment_init(rc.config_dir);
 	rcxml_read(config_file);
 
 	/*
@@ -171,7 +172,7 @@ main(int argc, char *argv[])
 
 	menu_init(&server);
 
-	session_autostart_init(rc.config_dir);
+	session_autostart_init();
 	if (startup_cmd) {
 		spawn_async_no_shell(startup_cmd);
 	}

src/menu/menu.c

@@ -11,6 +11,7 @@
 #include <wlr/util/log.h>
 #include "action.h"
 #include "common/buf.h"
+#include "common/dir.h"
 #include "common/font.h"
 #include "common/list.h"
 #include "common/match.h"
@@ -548,21 +549,27 @@ err:
 static void
 parse_xml(const char *filename, struct server *server)
 {
-	static char buf[4096] = { 0 };
+	struct wl_list paths;
+	paths_config_create(&paths, filename);
 
-	if (!rc.config_dir) {
+	bool should_merge_config = rc.merge_config;
-		return;
+	struct wl_list *(*iter)(struct wl_list *list);
-	}
+	iter = should_merge_config ? paths_get_prev : paths_get_next;
-	snprintf(buf, sizeof(buf), "%s/%s", rc.config_dir, filename);
 
-	FILE *stream = fopen(buf, "r");
+	for (struct wl_list *elm = iter(&paths); elm != &paths; elm = iter(elm)) {
-	if (!stream) {
+		struct path *path = wl_container_of(elm, path, link);
-		wlr_log(WLR_ERROR, "cannot read %s", buf);
+		FILE *stream = fopen(path->string, "r");
-		return;
+		if (!stream) {
+			return;
+		}
+		wlr_log(WLR_INFO, "read menu file %s", path->string);
+		parse(server, stream);
+		fclose(stream);
+		if (!should_merge_config) {
+			break;
+		}
 	}
-	wlr_log(WLR_INFO, "read menu file %s", buf);
+	paths_destroy(&paths);
-	parse(server, stream);
-	fclose(stream);
 }
 
 static int

src/server.c

@@ -67,7 +67,7 @@ reload_config_and_theme(void)
 static int
 handle_sighup(int signal, void *data)
 {
-	session_environment_init(rc.config_dir);
+	session_environment_init();
 	reload_config_and_theme();
 	return 0;
 }

src/theme.c

@@ -23,6 +23,7 @@
 #include "common/font.h"
 #include "common/graphic-helpers.h"
 #include "common/match.h"
+#include "common/mem.h"
 #include "common/string-helpers.h"
 #include "config/rcxml.h"
 #include "button/button-png.h"
@@ -664,60 +665,36 @@ process_line(struct theme *theme, char *line)
 }
 
 static void
-theme_read(struct theme *theme, const char *theme_name)
+theme_read(struct theme *theme, struct wl_list *paths)
 {
-	FILE *stream = NULL;
+	bool should_merge_config = rc.merge_config;
-	char *line = NULL;
+	struct wl_list *(*iter)(struct wl_list *list);
-	size_t len = 0;
+	iter = should_merge_config ? paths_get_prev : paths_get_next;
-	char themerc[4096];
 
-	if (strlen(theme_dir(theme_name))) {
+	for (struct wl_list *elm = iter(paths); elm != paths; elm = iter(elm)) {
-		snprintf(themerc, sizeof(themerc), "%s/themerc",
+		struct path *path = wl_container_of(elm, path, link);
-			theme_dir(theme_name));
+		FILE *stream = fopen(path->string, "r");
-		stream = fopen(themerc, "r");
+		if (!stream) {
-	}
+			continue;
-	if (!stream) {
-		if (theme_name) {
-			wlr_log(WLR_INFO, "cannot find theme %s", theme_name);
 		}
-		return;
+
-	}
+		wlr_log(WLR_INFO, "read theme %s", path->string);
-	wlr_log(WLR_INFO, "read theme %s", themerc);
+
-	while (getline(&line, &len, stream) != -1) {
+		char *line = NULL;
-		char *p = strrchr(line, '\n');
+		size_t len = 0;
-		if (p) {
+		while (getline(&line, &len, stream) != -1) {
-			*p = '\0';
+			char *p = strrchr(line, '\n');
+			if (p) {
+				*p = '\0';
+			}
+			process_line(theme, line);
 		}
-		process_line(theme, line);
+		zfree(line);
-	}
+		fclose(stream);
-	free(line);
+		if (!should_merge_config) {
-	fclose(stream);
+			break;
-}
-
-static void
-theme_read_override(struct theme *theme)
-{
-	char f[4096] = { 0 };
-	snprintf(f, sizeof(f), "%s/themerc-override", rc.config_dir);
-
-	FILE *stream = fopen(f, "r");
-	if (!stream) {
-		wlr_log(WLR_INFO, "no theme override '%s'", f);
-		return;
-	}
-
-	wlr_log(WLR_INFO, "read theme-override %s", f);
-	char *line = NULL;
-	size_t len = 0;
-	while (getline(&line, &len, stream) != -1) {
-		char *p = strrchr(line, '\n');
-		if (p) {
-			*p = '\0';
 		}
-		process_line(theme, line);
 	}
-	free(line);
-	fclose(stream);
 }
 
 struct rounded_corner_ctx {
@@ -1001,10 +978,15 @@ theme_init(struct theme *theme, const char *theme_name)
 	theme_builtin(theme);
 
 	/* Read <data-dir>/share/themes/$theme_name/openbox-3/themerc */
-	theme_read(theme, theme_name);
+	struct wl_list paths;
+	paths_theme_create(&paths, theme_name, "themerc");
+	theme_read(theme, &paths);
+	paths_destroy(&paths);
 
 	/* Read <config-dir>/labwc/themerc-override */
-	theme_read_override(theme);
+	paths_config_create(&paths, "themerc-override");
+	theme_read(theme, &paths);
+	paths_destroy(&paths);
 
 	post_processing(theme);
 	create_corners(theme);