very basic IPC implementation

simply executes the received data as command

include/ipc.h

@@ -0,0 +1,6 @@
+#ifndef _SWAY_IPC_H
+#define _SWAY_IPC_H
+
+void init_ipc(void);
+
+#endif

sway/ipc.c

@@ -0,0 +1,70 @@
+#include <errno.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <wlc/wlc.h>
+#include <unistd.h>
+#include "log.h"
+#include "config.h"
+#include "commands.h"
+
+static int ipc_socket = -1;
+
+int ipc_handle_connection(int fd, uint32_t mask, void *data);
+
+void init_ipc() {
+	ipc_socket = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0);
+	if (ipc_socket == -1) {
+		sway_abort("Unable to create IPC socket");
+	}
+
+	struct sockaddr_un ipc_sockaddr = {
+		.sun_family = AF_UNIX,
+		// TODO: use a proper socket path
+		.sun_path = "/tmp/sway.sock"
+	};
+
+	unlink(ipc_sockaddr.sun_path);
+	if (bind(ipc_socket, (struct sockaddr *)&ipc_sockaddr, sizeof(ipc_sockaddr)) == -1) {
+		sway_abort("Unable to bind IPC socket");
+	}
+
+	if (listen(ipc_socket, 3) == -1) {
+		sway_abort("Unable to listen on IPC socket");
+	}
+
+	wlc_event_loop_add_fd(ipc_socket, WLC_EVENT_READABLE, ipc_handle_connection, NULL);
+}
+
+int ipc_handle_connection(int /*fd*/, uint32_t /*mask*/, void */*data*/) {
+	int client_socket = accept(ipc_socket, NULL, NULL);
+	if (client_socket == -1) {
+		char error[256];
+		strerror_r(errno, error, sizeof(error));
+		sway_log(L_INFO, "Unable to accept IPC client connection: %s", error);
+		return 0;
+	}
+
+	char buf[1024];
+	if (recv(client_socket, buf, sizeof(buf), 0) == -1) {
+		char error[256];
+		strerror_r(errno, error, sizeof(error));
+		sway_log(L_INFO, "Unable to receive from IPC client: %s", error);
+		close(client_socket);
+		return 0;
+	}
+
+	sway_log(L_INFO, "Executing IPC command: %s", buf);
+
+	bool success = handle_command(config, buf);
+	snprintf(buf, sizeof(buf), "{\"success\":%s}\n", success ? "true" : "false");
+
+	if (send(client_socket, buf, strlen(buf), 0) == -1) {
+		char error[256];
+		strerror_r(errno, error, sizeof(error));
+		sway_log(L_INFO, "Unable to send to IPC client: %s", error);
+	}
+
+	close(client_socket);
+	return 0;
+}

sway/main.c

@@ -9,6 +9,7 @@
 #include "config.h"
 #include "log.h"
 #include "handlers.h"
+#include "ipc.h"
 
 static void sigchld_handle(int signal);
 
@@ -99,6 +100,8 @@ int main(int argc, char **argv) {
 		free(config_path);
 	}
 
+	init_ipc();
+
 	wlc_run();
 	if (devnull) {
 		fclose(devnull);