Add wayvncctl --wait option

Signed-off-by: Jim Ramsay <i.am@jimramsay.com>

include/ctl-client.h

@@ -28,5 +28,6 @@ void* ctl_client_userdata(struct ctl_client*);
 
 #define PRINT_JSON 0x00000001
 
+int ctl_client_connect(struct ctl_client* self, int timeout);
 int ctl_client_run_command(struct ctl_client* self,
 		int argc, char* argv[], unsigned flags);

src/ctl-client.c

@@ -20,8 +20,10 @@
 #include <errno.h>
 #include <sys/socket.h>
 #include <sys/un.h>
+#include <sys/stat.h>
 #include <poll.h>
 #include <signal.h>
+#include <assert.h>
 #include <jansson.h>
 
 #include "json-ipc.h"
@@ -39,11 +41,12 @@ static bool do_debug = false;
 	if (do_debug) \
 		fprintf(stderr, "[%s:%d] " fmt "\n", __FILE__, __LINE__, ##__VA_ARGS__);
 
-#define FAILED_TO(action) \
+#define FAILED_TO(action, ...) \
-	WARN("Failed to " action ": %m");
+	WARN("Failed to " action ": %m", ##__VA_ARGS__);
 
 struct ctl_client {
 	void* userdata;
+	struct sockaddr_un addr;
 
 	char read_buffer[512];
 	size_t read_len;
@@ -65,37 +68,76 @@ struct ctl_client* ctl_client_new(const char* socket_path, void* userdata)
 	struct ctl_client* new = calloc(1, sizeof(*new));
 	new->userdata = userdata;
 
-	struct sockaddr_un addr = {
+	if (strlen(socket_path) >= sizeof(new->addr.sun_path)) {
-		.sun_family = AF_UNIX,
-	};
-
-	if (strlen(socket_path) >= sizeof(addr.sun_path)) {
 		errno = ENAMETOOLONG;
 		FAILED_TO("create unix socket");
 		goto socket_failure;
 	}
-	strcpy(addr.sun_path, socket_path);
+	strcpy(new->addr.sun_path, socket_path);
+	new->addr.sun_family = AF_UNIX;
 
 	new->fd = socket(AF_UNIX, SOCK_STREAM, 0);
 	if (new->fd < 0) {
 		FAILED_TO("create unix socket");
 		goto socket_failure;
 	}
-
-	if (connect(new->fd, (struct sockaddr*)&addr, sizeof(addr)) != 0) {
-		FAILED_TO("connect to unix socket");
-		goto connect_failure;
-	}
-
 	return new;
 
-connect_failure:
-	close(new->fd);
 socket_failure:
 	free(new);
 	return NULL;
 }
 
+int ctl_client_connect(struct ctl_client* self, int timeout)
+{
+	// TODO: Support arbitrary timeouts?
+	assert(timeout == 0 || timeout == -1);
+	// TODO: Use inotify instead of polling stat()
+	bool needs_log = true;
+	struct stat sb;
+	while (stat(self->addr.sun_path, &sb) != 0) {
+		if (timeout == 0) {
+			FAILED_TO("find socket path \"%s\"",
+					self->addr.sun_path);
+			goto stat_failure;
+		}
+		if (needs_log) {
+			needs_log = false;
+			DEBUG("Waiting for socket path \"%s\" to appear",
+					self->addr.sun_path);
+		}
+		if (usleep(50000) == -1) {
+			FAILED_TO("wait for socket path");
+			goto stat_failure;
+		}
+	}
+	if (S_ISSOCK(sb.st_mode)) {
+		DEBUG("Found socket \"%s\"", self->addr.sun_path);
+	} else {
+		WARN("Path \"%s\" exists but is not a socket (0x%x)",
+				self->addr.sun_path, sb.st_mode);
+		goto stat_failure;
+	}
+	while (connect(self->fd, (struct sockaddr*)&self->addr,
+				sizeof(self->addr)) != 0) {
+		if (timeout == 0 || errno != ENOENT) {
+			FAILED_TO("connect to unix socket \"%s\"",
+					self->addr.sun_path);
+			goto stat_failure;
+			return 1;
+		}
+		if (usleep(50000) == -1) {
+			FAILED_TO("wait for connect to succeed");
+			return 1;
+		}
+	}
+
+	return 0;
+
+stat_failure:
+	return 1;
+}
+
 void ctl_client_destroy(struct ctl_client* self)
 {
 	close(self->fd);

src/wayvncctl.c

@@ -53,6 +53,8 @@ static int wayvncctl_usage(FILE* stream, int rc)
 "Options:\n"
 "    -S,--socket=<path>                   Wayvnc control socket path.\n"
 "                                         Default: $XDG_RUNTIME_DIR/wayvncctl\n"
+"    -w,--wait                            Wait for wayvnc to start up if it's\n"
+"                                         not already running.\n"
 "    -j,--json                            Output json on stdout.\n"
 "    -V,--version                         Show version info.\n"
 "    -v,--verbose                         Be more verbose.\n"
@@ -74,15 +76,17 @@ int main(int argc, char* argv[])
 {
 	struct wayvncctl self = { 0 };
 
-	static const char* shortopts = "+S:hVvj";
+	static const char* shortopts = "+S:hVvjw";
 
 	bool verbose = false;
 	const char* socket_path = NULL;
+	int wait_for_socket = 0;
 
 	unsigned flags = 0;
 
 	static const struct option longopts[] = {
 		{ "socket", required_argument, NULL, 'S' },
+		{ "wait", no_argument, NULL, 'w' },
 		{ "json", no_argument, NULL, 'j' },
 		{ "help", no_argument, NULL, 'h' },
 		{ "version", no_argument, NULL, 'V' },
@@ -99,6 +103,9 @@ int main(int argc, char* argv[])
 		case 'S':
 			socket_path = optarg;
 			break;
+		case 'w':
+			wait_for_socket = -1;
+			break;
 		case 'j':
 			flags |= PRINT_JSON;
 			break;
@@ -117,12 +124,18 @@ int main(int argc, char* argv[])
 	argv = &argv[optind];
 
 	ctl_client_debug_log(verbose);
+
 	self.ctl = ctl_client_new(socket_path, &self);
 	if (!self.ctl)
 		goto ctl_client_failure;
 
-	int result = ctl_client_run_command(self.ctl, argc, argv, flags);
+	int result = ctl_client_connect(self.ctl, wait_for_socket);
+	if (result != 0)
+		goto socket_failure;
 
+	result = ctl_client_run_command(self.ctl, argc, argv, flags);
+
+socket_failure:
 	ctl_client_destroy(self.ctl);
 
 	return result;

wayvncctl.scd

@@ -14,6 +14,10 @@ wayvncctl - A command line control client for wayvnc(1)
 	Set wayvnc control socket path. Default: $XDG_RUNTIME_DIR/wayvncctl
 	or /tmp/wayvncctl-$UID
 
+*-w, --wait*
+	Wait for wayvnc to start up if it's not already running. Default: Exit
+	immediately with an error if wayvnc is not running.
+
 *-j, --json*
 	Produce json output to stdout.