1 files changed, 229 insertions, 0 deletions
diff --git a/sway/ipc.c b/sway/ipc.c
new file mode 100644
index 00000000..505c17f8
--- /dev/null
+++ b/sway/ipc.c
@@ -0,0 +1,229 @@
+// See https://i3wm.org/docs/ipc.html for protocol information
+
+#include <errno.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <stdbool.h>
+#include <wlc/wlc.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stropts.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include "ipc.h"
+#include "log.h"
+#include "config.h"
+#include "commands.h"
+
+static int ipc_socket = -1;
+static struct wlc_event_source *ipc_event_source =  NULL;
+static struct sockaddr_un ipc_sockaddr = {
+	.sun_family = AF_UNIX,
+	.sun_path = "/tmp/sway-ipc.sock"
+};
+
+static const char ipc_magic[] = {'i', '3', '-', 'i', 'p', 'c'};
+
+struct ipc_client {
+	struct wlc_event_source *event_source;
+	int fd;
+	uint32_t payload_length;
+	enum ipc_command_type current_command;
+};
+
+int ipc_handle_connection(int fd, uint32_t mask, void *data);
+int ipc_client_handle_readable(int client_fd, uint32_t mask, void *data);
+void ipc_client_disconnect(struct ipc_client *client);
+void ipc_client_handle_command(struct ipc_client *client);
+bool ipc_send_reply(struct ipc_client *client, const char *payload, uint32_t payload_length);
+
+void ipc_init(void) {
+	ipc_socket = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0);
+	if (ipc_socket == -1) {
+		sway_abort("Unable to create IPC socket");
+	}
+
+	if (getenv("SWAYSOCK") != NULL) {
+		strncpy(ipc_sockaddr.sun_path, getenv("SWAYSOCK"), sizeof(ipc_sockaddr.sun_path));
+	}
+
+	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");
+	}
+
+	// Set i3 IPC socket path so that i3-msg works out of the box
+	setenv("I3SOCK", ipc_sockaddr.sun_path, 1);
+
+	ipc_event_source = wlc_event_loop_add_fd(ipc_socket, WLC_EVENT_READABLE, ipc_handle_connection, NULL);
+}
+
+void ipc_terminate(void) {
+	if (ipc_event_source) {
+		wlc_event_source_remove(ipc_event_source);
+	}
+	close(ipc_socket);
+	unlink(ipc_sockaddr.sun_path);
+}
+
+int ipc_handle_connection(int fd, uint32_t mask, void *data) {
+	(void) fd; (void) data;
+	sway_log(L_DEBUG, "Event on IPC listening socket");
+	assert(mask == WLC_EVENT_READABLE);
+
+	int client_fd = accept(ipc_socket, NULL, NULL);
+	if (client_fd == -1) {
+		sway_log_errno(L_INFO, "Unable to accept IPC client connection");
+		return 0;
+	}
+
+	int flags;
+	if ((flags=fcntl(client_fd, F_GETFD)) == -1 || fcntl(client_fd, F_SETFD, flags|FD_CLOEXEC) == -1) {
+		sway_log_errno(L_INFO, "Unable to set CLOEXEC on IPC client socket");
+		return 0;
+	}
+
+	struct ipc_client* client = malloc(sizeof(struct ipc_client));
+	client->payload_length = 0;
+	client->fd = client_fd;
+	client->event_source = wlc_event_loop_add_fd(client_fd, WLC_EVENT_READABLE, ipc_client_handle_readable, client);
+
+	return 0;
+}
+
+static const int ipc_header_size = sizeof(ipc_magic)+8;
+
+int ipc_client_handle_readable(int client_fd, uint32_t mask, void *data) {
+	struct ipc_client *client = data;
+	sway_log(L_DEBUG, "Event on IPC client socket %d", client_fd);
+
+	if (mask & WLC_EVENT_ERROR) {
+		sway_log(L_INFO, "IPC Client socket error, removing client");
+		ipc_client_disconnect(client);
+		return 0;
+	}
+
+	if (mask & WLC_EVENT_HANGUP) {
+		ipc_client_disconnect(client);
+		return 0;
+	}
+
+	int read_available;
+	ioctl(client_fd, FIONREAD, &read_available);
+
+	// Wait for the rest of the command payload in case the header has already been read
+	if (client->payload_length > 0) {
+		if (read_available >= client->payload_length) {
+			ipc_client_handle_command(client);
+		}
+		else {
+			sway_log(L_DEBUG, "Too little data to read payload on IPC Client socket, waiting for more (%d < %d)", read_available, client->payload_length);
+		}
+		return 0;
+	}
+
+	if (read_available < ipc_header_size) {
+		sway_log(L_DEBUG, "Too little data to read header on IPC Client socket, waiting for more (%d < %d)", read_available, ipc_header_size);
+		return 0;
+	}
+
+	char buf[ipc_header_size];
+	ssize_t received = recv(client_fd, buf, ipc_header_size, 0);
+	if (received == -1) {
+		sway_log_errno(L_INFO, "Unable to receive header from IPC client");
+		ipc_client_disconnect(client);
+		return 0;
+	}
+
+	if (memcmp(buf, ipc_magic, sizeof(ipc_magic)) != 0) {
+		sway_log(L_DEBUG, "IPC header check failed");
+		ipc_client_disconnect(client);
+		return 0;
+	}
+
+	client->payload_length = *(uint32_t *)&buf[sizeof(ipc_magic)];
+	client->current_command = (enum ipc_command_type) *(uint32_t *)&buf[sizeof(ipc_magic)+4];
+
+	if (read_available - received >= client->payload_length) {
+		ipc_client_handle_command(client);
+	}
+
+	return 0;
+}
+
+void ipc_client_disconnect(struct ipc_client *client)
+{
+	if (!sway_assert(client != NULL, "client != NULL")) {
+		return;
+	}
+
+	sway_log(L_INFO, "IPC Client %d disconnected", client->fd);
+	wlc_event_source_remove(client->event_source);
+	close(client->fd);
+	free(client);
+}
+
+void ipc_client_handle_command(struct ipc_client *client) {
+	if (!sway_assert(client != NULL, "client != NULL")) {
+		return;
+	}
+
+	char buf[client->payload_length + 1];
+	if (client->payload_length > 0)
+	{
+		ssize_t received = recv(client->fd, buf, client->payload_length, 0);
+		if (received == -1)
+		{
+			sway_log_errno(L_INFO, "Unable to receive payload from IPC client");
+			ipc_client_disconnect(client);
+			return;
+		}
+	}
+
+	switch (client->current_command) {
+	case IPC_COMMAND:
+	{
+		buf[client->payload_length] = '\0';
+		bool success = handle_command(config, buf);
+		char reply[64];
+		int length = snprintf(reply, sizeof(reply), "{\"success\":%s}", success ? "true" : "false");
+		ipc_send_reply(client, reply, (uint32_t) length);
+		break;
+	}
+	default:
+		sway_log(L_INFO, "Unknown IPC command type %i", client->current_command);
+		ipc_client_disconnect(client);
+		break;
+	}
+
+	client->payload_length = 0;
+}
+
+bool ipc_send_reply(struct ipc_client *client, const char *payload, uint32_t payload_length) {
+	assert(payload);
+
+	char data[ipc_header_size];
+
+	memcpy(data, ipc_magic, sizeof(ipc_magic));
+	*(uint32_t *)&(data[sizeof(ipc_magic)]) = payload_length;
+	*(uint32_t *)&(data[sizeof(ipc_magic)+4]) = client->current_command;
+
+	if (write(client->fd, data, ipc_header_size) == -1) {
+		sway_log_errno(L_INFO, "Unable to send header to IPC client");
+		ipc_client_disconnect(client);
+		return false;
+	}
+
+	if (write(client->fd, payload, payload_length) == -1) {
+		sway_log_errno(L_INFO, "Unable to send payload to IPC client");
+		ipc_client_disconnect(client);
+		return false;
+	}
+
+	return true;
+}