Add sandbox_socket command

This command can be used to create a new listening socket (suitable for use in
WAYLAND_DISPLAY) whose clients will all have a specific label.

Co-authored-by: Mykola Orliuk <virkony@gmail.com>

include/sway/commands.h

@@ -307,4 +307,6 @@ sway_cmd cmd_ipc_cmd;
 sway_cmd cmd_ipc_events;
 sway_cmd cmd_ipc_event_cmd;
 
+sway_cmd cmd_sandbox_socket;
+
 #endif

sway/commands.c

@@ -81,6 +81,7 @@ static const struct cmd_handler handlers[] = {
 	{ "no_focus", cmd_no_focus },
 	{ "output", cmd_output },
 	{ "popup_during_fullscreen", cmd_popup_during_fullscreen },
+	{ "sandbox_socket", cmd_sandbox_socket },
 	{ "seat", cmd_seat },
 	{ "set", cmd_set },
 	{ "show_marks", cmd_show_marks },

sway/commands/sandbox_socket.c

@@ -0,0 +1,147 @@
+#define _XOPEN_SOURCE 700 // for strdup
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <strings.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <wayland-server-core.h>
+#include "sway/client_label.h"
+#include "sway/commands.h"
+#include "sway/tree/container.h"
+#include "sway/tree/view.h"
+#include "list.h"
+#include "log.h"
+#include "util.h"
+
+struct sandbox_socket {
+	char* path;
+	struct wl_event_source *src;
+	int fd;
+	char* label;
+};
+
+static list_t *sandbox_sockets;
+
+static int fd_accept(int srv_fd, uint32_t mask, void *data) {
+	struct sandbox_socket *sock = data;
+
+	int cli_fd = accept(srv_fd, NULL, NULL);
+	if (cli_fd < 0) {
+		if (errno == EINTR || errno == ECONNABORTED || errno == EAGAIN || errno == EWOULDBLOCK) {
+			return 1;
+		} else {
+			int i;
+			wl_event_source_remove(sock->src);
+			unlink(sock->path);
+			free(sock->path);
+			close(srv_fd);
+			for(i = 0; i < sandbox_sockets->length; ++i) {
+				if (sock != sandbox_sockets->items[i])
+					continue;
+				list_del(sandbox_sockets, i);
+				break;
+			}
+			free(sock);
+			return 0;
+		}
+	}
+
+	sway_set_cloexec(cli_fd, true);
+	struct wl_client* client = wl_client_create(server.wl_display, cli_fd);
+	if (client) {
+		wl_client_label_set(client, strdup(sock->label));
+	} else {
+		close(cli_fd);
+	}
+
+	return 1;
+}
+
+struct cmd_results *cmd_sandbox_socket(int argc, char **argv) {
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, "sandbox_socket", EXPECTED_AT_LEAST, 2))) {
+		return error;
+	}
+
+	if (!sandbox_sockets)
+		sandbox_sockets = create_list();
+
+	char* op = argv[0];
+
+	if (strcmp(op, "create") == 0) {
+		struct sockaddr_un name = {};
+		char* label = NULL;
+		int i = 1;
+		while (i < argc) {
+			if (strcmp(argv[i], "--label") == 0) {
+				if (i + 1 >= argc)
+					return cmd_results_new(CMD_INVALID, "--label requires an argument");
+				label = argv[i + 1];
+				i += 2;
+			} else if (strcmp(argv[i], "--") == 0) {  // after this any argument should be treated as positional
+				++i;
+				break;
+			} else if (strncmp(argv[i], "-", 1) == 0) {
+				return cmd_results_new(CMD_INVALID, "Unknown option to sandbox_socket");
+			} else {
+				break;  // end of options, now only positional arguments
+			}
+		}
+
+		if ((error = checkarg(argc, "sandbox_socket", EXPECTED_EQUAL_TO, i + 1))) {
+			return error;
+		}
+		char *path = argv[i];
+		size_t path_len = strlen(path) + 1;
+
+		if (path_len > sizeof(name.sun_path)) {
+			return cmd_results_new(CMD_INVALID, "Invalid socket path: %s", path);
+		}
+		unlink(path);
+
+		name.sun_family = AF_UNIX;
+		memcpy(name.sun_path, path, path_len);
+		size_t name_len = offsetof(struct sockaddr_un, sun_path) + path_len;
+
+		int srv_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+		if (srv_fd < 0 ||
+				!sway_set_cloexec(srv_fd, true) ||
+				fcntl(srv_fd, F_SETFL, O_NONBLOCK) != 0 ||
+				bind(srv_fd, (struct sockaddr *)&name, name_len) != 0 ||
+				listen(srv_fd, 5) != 0) {
+			close(srv_fd);
+			return cmd_results_new(CMD_FAILURE, "Error creating socket: %s", strerror(errno));
+		}
+
+		struct sandbox_socket *sock = calloc(1, sizeof(*sock));
+		sock->path = strdup(path);
+		sock->src = wl_event_loop_add_fd(server.wl_event_loop, srv_fd, WL_EVENT_READABLE, fd_accept, sock);
+		sock->fd = srv_fd;
+		if (label)
+			sock->label = strdup(label);
+
+		list_add(sandbox_sockets, sock);
+		return cmd_results_new(CMD_SUCCESS, NULL);
+	} else if (strcmp(op, "delete") == 0) {
+		char* path = argv[1];
+		int i;
+		for(i = 0; i < sandbox_sockets->length; ++i) {
+			struct sandbox_socket *sock = sandbox_sockets->items[i];
+			if (strcmp(sock->path, path) == 0) {
+				wl_event_source_remove(sock->src);
+				unlink(path);
+				close(sock->fd);
+				free(sock->path);
+				free(sock->label);
+				free(sock);
+				list_del(sandbox_sockets, i);
+				return cmd_results_new(CMD_SUCCESS, NULL);
+			}
+		}
+		return cmd_results_new(CMD_FAILURE, "sandbox_socket: %s not found", path);
+	} else {
+		return cmd_results_new(CMD_INVALID, "Unknown command sandbox_socket %s", op);
+	}
+}

sway/meson.build

@@ -86,6 +86,7 @@ sway_sources = files(
 	'commands/reload.c',
 	'commands/rename.c',
 	'commands/resize.c',
+	'commands/sandbox_socket.c',
 	'commands/scratchpad.c',
 	'commands/seat.c',
 	'commands/seat/attach.c',