labwc-ipc.patch

diff --git a/include/ipc.h b/include/ipc.h
new file mode 100644
index 00000000..7be67068
--- /dev/null
+++ b/include/ipc.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef LABWC_IPC_H
+#define LABWC_IPC_H
+
+struct server;
+
+void ipc_init(struct server *server);
+void ipc_finish(struct server *server);
+
+#endif /* LABWC_IPC_H */
diff --git a/include/labwc.h b/include/labwc.h
index 88860de2..9235aa2b 100644
--- a/include/labwc.h
+++ b/include/labwc.h
@@ -311,6 +311,7 @@ struct server {
 	struct sfdo *sfdo;
 
 	pid_t primary_client_pid;
+	bool ipc;
 };
 
 void xdg_popup_create(struct view *view, struct wlr_xdg_popup *wlr_popup);
diff --git a/src/ipc.c b/src/ipc.c
new file mode 100644
index 00000000..e763d9e3
--- /dev/null
+++ b/src/ipc.c
@@ -0,0 +1,298 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#define _POSIX_C_SOURCE 200809L
+#include "config.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <wlr/util/log.h>
+#include "ipc.h"
+#include "labwc.h"
+#include "view.h"
+
+#define IPC_BUF_SIZE 4096
+
+static int listen_fd = -1;
+static struct wl_event_source *listen_source;
+static struct server *ipc_server;
+
+struct ipc_client {
+	int fd;
+	struct wl_event_source *source;
+	struct server *server;
+	char buf[IPC_BUF_SIZE];
+	size_t buf_len;
+};
+
+static void
+ipc_client_destroy(struct ipc_client *client)
+{
+	wl_event_source_remove(client->source);
+	close(client->fd);
+	free(client);
+}
+
+static void
+json_escape(char *dst, size_t dst_size, const char *src)
+{
+	size_t j = 0;
+	for (size_t i = 0; src[i] && j < dst_size - 2; i++) {
+		char c = src[i];
+		if (c == '"' || c == '\\') {
+			if (j + 2 >= dst_size) {
+				break;
+			}
+			dst[j++] = '\\';
+			dst[j++] = c;
+		} else if (c >= 0x20) {
+			dst[j++] = c;
+		}
+	}
+	dst[j] = '\0';
+}
+
+static void
+view_to_json(struct wl_array *out, struct view *view, struct server *server)
+{
+	char title_esc[512];
+	char app_id_esc[512];
+	pid_t pid = view->impl->get_pid(view);
+
+	json_escape(title_esc, sizeof(title_esc),
+		view->title ? view->title : "");
+	json_escape(app_id_esc, sizeof(app_id_esc),
+		view->app_id ? view->app_id : "");
+
+	char entry[2048];
+	int len = snprintf(entry, sizeof(entry),
+		"{\"pid\":%d,"
+		"\"x\":%d,\"y\":%d,\"width\":%d,\"height\":%d,"
+		"\"title\":\"%s\",\"app_id\":\"%s\","
+		"\"minimized\":%s,\"fullscreen\":%s,"
+		"\"maximized\":%s,\"tiled\":%s,\"focused\":%s}",
+		(int)pid,
+		view->current.x, view->current.y,
+		view->current.width, view->current.height,
+		title_esc, app_id_esc,
+		view->minimized ? "true" : "false",
+		view->fullscreen ? "true" : "false",
+		view->maximized != VIEW_AXIS_NONE ? "true" : "false",
+		view->tiled != LAB_EDGE_NONE ? "true" : "false",
+		view == server->active_view ? "true" : "false");
+
+	char *p = wl_array_add(out, len);
+	if (p) {
+		memcpy(p, entry, len);
+	}
+}
+
+static void
+ipc_respond(int fd, const char *data, size_t len)
+{
+	size_t total = len;
+	const char *ptr = data;
+	while (total > 0) {
+		ssize_t n = write(fd, ptr, total);
+		if (n <= 0) {
+			break;
+		}
+		ptr += n;
+		total -= n;
+	}
+}
+
+static void
+ipc_handle_command(struct ipc_client *client, const char *cmd)
+{
+	struct server *server = client->server;
+	struct wl_array buf;
+	wl_array_init(&buf);
+
+	if (strncmp(cmd, "GET_WINDOWS", 11) == 0) {
+		char *p = wl_array_add(&buf, 1);
+		*p = '[';
+		bool first = true;
+		struct view *view;
+		wl_list_for_each(view, &server->views, link) {
+			if (!first) {
+				p = wl_array_add(&buf, 1);
+				*p = ',';
+			}
+			first = false;
+			view_to_json(&buf, view, server);
+		}
+		p = wl_array_add(&buf, 1);
+		*p = ']';
+
+	} else if (strncmp(cmd, "GET_WINDOW_BY_PID ", 18) == 0) {
+		int target_pid = atoi(cmd + 18);
+		struct view *view;
+		bool found = false;
+		wl_list_for_each(view, &server->views, link) {
+			pid_t pid = view->impl->get_pid(view);
+			if (pid == (pid_t)target_pid) {
+				view_to_json(&buf, view, server);
+				found = true;
+				break;
+			}
+		}
+		if (!found) {
+			char *p = wl_array_add(&buf, 4);
+			memcpy(p, "null", 4);
+		}
+
+	} else if (strncmp(cmd, "GET_FOCUSED_WINDOW", 18) == 0) {
+		if (server->active_view) {
+			view_to_json(&buf, server->active_view, server);
+		} else {
+			char *p = wl_array_add(&buf, 4);
+			memcpy(p, "null", 4);
+		}
+	} else {
+		const char *err = "{\"error\":\"unknown command\"}";
+		size_t err_len = strlen(err);
+		char *p = wl_array_add(&buf, err_len);
+		memcpy(p, err, err_len);
+	}
+
+	ipc_respond(client->fd, buf.data, buf.size);
+	char nl = '\n';
+	ipc_respond(client->fd, &nl, 1);
+	wl_array_release(&buf);
+}
+
+static int
+ipc_client_readable(int fd, uint32_t mask, void *data)
+{
+	struct ipc_client *client = data;
+
+	if (mask & WL_EVENT_HANGUP) {
+		ipc_client_destroy(client);
+		return 0;
+	}
+
+	if (mask & WL_EVENT_READABLE) {
+		size_t space = sizeof(client->buf) - client->buf_len - 1;
+		if (space == 0) {
+			ipc_client_destroy(client);
+			return 0;
+		}
+		ssize_t n = read(fd, client->buf + client->buf_len, space);
+		if (n <= 0) {
+			ipc_client_destroy(client);
+			return 0;
+		}
+		client->buf_len += n;
+		client->buf[client->buf_len] = '\0';
+
+		char *newline = strchr(client->buf, '\n');
+		if (newline) {
+			*newline = '\0';
+			ipc_handle_command(client, client->buf);
+			ipc_client_destroy(client);
+		}
+	}
+	return 0;
+}
+
+static int
+ipc_listen_readable(int fd, uint32_t mask, void *data)
+{
+	if (!(mask & WL_EVENT_READABLE)) {
+		return 0;
+	}
+
+	int client_fd = accept(fd, NULL, NULL);
+	if (client_fd < 0) {
+		wlr_log_errno(WLR_ERROR, "ipc: accept");
+		return 0;
+	}
+
+	int flags = fcntl(client_fd, F_GETFL, 0);
+	fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
+
+	struct ipc_client *client = calloc(1, sizeof(*client));
+	if (!client) {
+		close(client_fd);
+		return 0;
+	}
+	client->fd = client_fd;
+	client->server = ipc_server;
+	client->source = wl_event_loop_add_fd(
+		ipc_server->wl_event_loop, client_fd,
+		WL_EVENT_READABLE | WL_EVENT_HANGUP,
+		ipc_client_readable, client);
+
+	return 0;
+}
+
+void
+ipc_init(struct server *server)
+{
+	ipc_server = server;
+
+	const char *runtime = getenv("XDG_RUNTIME_DIR");
+	if (!runtime) {
+		wlr_log(WLR_ERROR, "ipc: XDG_RUNTIME_DIR not set");
+		return;
+	}
+
+	char path[256];
+	snprintf(path, sizeof(path), "%s/labwc.sock", runtime);
+
+	unlink(path);
+
+	struct sockaddr_un addr;
+	memset(&addr, 0, sizeof(addr));
+	addr.sun_family = AF_UNIX;
+	strncpy(addr.sun_path, path, sizeof(addr.sun_path) - 1);
+
+	listen_fd = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0);
+	if (listen_fd < 0) {
+		wlr_log_errno(WLR_ERROR, "ipc: socket");
+		return;
+	}
+
+	if (bind(listen_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+		wlr_log_errno(WLR_ERROR, "ipc: bind %s", path);
+		close(listen_fd);
+		listen_fd = -1;
+		return;
+	}
+
+	if (listen(listen_fd, 5) < 0) {
+		wlr_log_errno(WLR_ERROR, "ipc: listen");
+		close(listen_fd);
+		listen_fd = -1;
+		return;
+	}
+
+	listen_source = wl_event_loop_add_fd(
+		server->wl_event_loop, listen_fd,
+		WL_EVENT_READABLE, ipc_listen_readable, NULL);
+
+	wlr_log(WLR_INFO, "ipc: listening on %s", path);
+}
+
+void
+ipc_finish(struct server *server)
+{
+	if (listen_source) {
+		wl_event_source_remove(listen_source);
+		listen_source = NULL;
+	}
+	if (listen_fd >= 0) {
+		close(listen_fd);
+		listen_fd = -1;
+	}
+	const char *runtime = getenv("XDG_RUNTIME_DIR");
+	if (runtime) {
+		char path[256];
+		snprintf(path, sizeof(path), "%s/labwc.sock", runtime);
+		unlink(path);
+	}
+}
diff --git a/src/main.c b/src/main.c
index 755a0a0c..a9906e9f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -9,6 +9,7 @@
 #include "common/spawn.h"
 #include "config/rcxml.h"
 #include "config/session.h"
+#include "ipc.h"
 #include "labwc.h"
 #include "theme.h"
 #include "translate.h"
@@ -22,6 +23,7 @@ static const struct option long_options[] = {
 	{"debug", no_argument, NULL, 'd'},
 	{"exit", no_argument, NULL, 'e'},
 	{"help", no_argument, NULL, 'h'},
+	{"ipc", no_argument, NULL, 'i'},
 	{"merge-config", no_argument, NULL, 'm'},
 	{"reconfigure", no_argument, NULL, 'r'},
 	{"startup", required_argument, NULL, 's'},
@@ -38,6 +40,7 @@ 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"
+"  -i, --ipc                Enable IPC socket at $XDG_RUNTIME_DIR/labwc.sock\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"
@@ -154,12 +157,13 @@ main(int argc, char *argv[])
 {
 	char *startup_cmd = NULL;
 	char *primary_client = NULL;
+	bool ipc_enabled = false;
 	enum wlr_log_importance verbosity = WLR_ERROR;
 
 	int c;
 	while (1) {
 		int index = 0;
-		c = getopt_long(argc, argv, "c:C:dehmrs:S:vV", long_options, &index);
+		c = getopt_long(argc, argv, "c:C:dehimrs:S:vV", long_options, &index);
 		if (c == -1) {
 			break;
 		}
@@ -195,6 +199,10 @@ main(int argc, char *argv[])
 			verbosity = WLR_INFO;
 			break;
 		case 'h':
+			usage();
+		case 'i':
+			ipc_enabled = true;
+			break;
 		default:
 			usage();
 		}
@@ -247,6 +255,7 @@ main(int argc, char *argv[])
 	increase_nofile_limit();
 
 	struct server server = { 0 };
+	server.ipc = ipc_enabled;
 	server_init(&server);
 	server_start(&server);
 
diff --git a/src/meson.build b/src/meson.build
index a9afdc4f..65dbde3c 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -7,6 +7,7 @@ labwc_sources = files(
   'edges.c',
   'idle.c',
   'interactive.c',
+  'ipc.c',
   'layers.c',
   'magnifier.c',
   'main.c',
diff --git a/src/server.c b/src/server.c
index b8abc633..e7559ec7 100644
--- a/src/server.c
+++ b/src/server.c
@@ -52,6 +52,7 @@
 #include "desktop-entry.h"
 #include "idle.h"
 #include "input/keyboard.h"
+#include "ipc.h"
 #include "labwc.h"
 #include "layers.h"
 #include "magnifier.h"
@@ -729,6 +730,10 @@ server_init(struct server *server)
 #if HAVE_XWAYLAND
 	xwayland_server_init(server, server->compositor);
 #endif
+
+	if (server->ipc) {
+		ipc_init(server);
+	}
 }
 
 void
@@ -763,6 +768,8 @@ server_start(struct server *server)
 void
 server_finish(struct server *server)
 {
+	ipc_finish(server);
+
 #if HAVE_XWAYLAND
 	xwayland_server_finish(server);
 #endif