Auto-detect local noauth socket

Attempt to connect to local noauth socket, unless TCP or SHS options are specified.
Fall back to TCP+SHS connection, unless noauth option is specified.

sbotc.1

@@ -11,7 +11,7 @@
 .Op Fl T
 .
 .Oo
-.Op Fl n
+.Fl n
 |
 .Op Fl c Ar cap
 .Op Fl k Ar key
@@ -104,11 +104,32 @@ secret-handshake protocol.
 A map of method names to method types.
 .It Pa ~/.ssb/config
 JSON file containing key, host, port, and/or SHS cap key to use if the
-.Ar -s ,
-.Ar -p
+.Fl s ,
+.Fl p
 or
-.Ar -c
+.Fl c
 options are not given, respectively.
+.It Pa ~/.ssb/socket
+UNIX socket stream file for noauth connections.
+If none of the options
+.Fl s ,
+.Fl p ,
+.Fl u ,
+.Fl c ,
+.Fl k ,
+.Fl K ,
+.Fl c ,
+or
+.Fl T
+are specified,
+.Nm
+will attempt to connect in noauth mode to this socket file. If the socket file
+is not present or the connection fails,
+.Nm
+will fall back to connecting with TCP and secret-handshake according to the
+config file - unless the
+.Fl n
+option is specified, in which case the command will fail.
 .El
 .Pp
 The base path

sbotc.c

@@ -98,7 +98,7 @@ static const unsigned char ssb_cap[] = {
 
 static void usage() {
 	fputs("usage: sbotc [-j] [-T]\n"
-	      "             [ [-n] | [-c <cap>] [-k <key>] [-K <keypair_seed>] ]\n"
+	      "             [ -n | [-c <cap>] [-k <key>] [-K <keypair_seed>] ]\n"
 	      "             [ [-s <host>] [-p <port>] | [-u <socket_path>] ]\n"
 	      "             [-t <type>] <method> [<argument>...]\n", stderr);
 	exit(EXIT_FAILURE);
@@ -132,6 +132,31 @@ static int tcp_connect(const char *host, const char *port) {
 	return fd;
 }
 
+static int unix_connect(const char *path) {
+	struct sockaddr_un name;
+	const size_t path_len = strlen(path);
+	int s, rc;
+	if (path_len >= sizeof(name.sun_path)-1) errx(1, "socket path too long");
+	s = socket(AF_UNIX, SOCK_STREAM, 0);
+	if (s < 0) return -1;
+	memset(&name, 0, sizeof(struct sockaddr_un));
+	name.sun_family = AF_UNIX;
+	strncpy(name.sun_path, path, sizeof(name.sun_path) - 1);
+	rc = connect(s, (const struct sockaddr *)&name, sizeof name);
+	if (rc < 0) return -1;
+	return s;
+}
+
+static int get_socket_path(char *buf, size_t len, const char *app_dir) {
+	struct stat st;
+	int sz = snprintf(buf, len-1, "%s/%s", app_dir, "socket");
+	if (sz < 0 || sz >= (int)len-1) err(1, "failed to get socket path");
+	int rc = stat(buf, &st);
+	if (rc < 0) return -1;
+	if (!(st.st_mode & S_IFSOCK)) { errno = EINVAL; return -1; }
+	return 0;
+}
+
 static int read_all(int fd, void *buf, size_t count) {
 	ssize_t nbytes;
 	while (count > 0) {
@@ -836,6 +861,7 @@ int main(int argc, char *argv[]) {
 	bool noauth = false;
 	bool host_arg = false;
 	bool port_arg = false;
+	bool key_arg = false;
 	bool shs_cap_key_str_arg = false;
 
 	get_app_dir(app_dir, sizeof(app_dir));
@@ -861,7 +887,7 @@ int main(int argc, char *argv[]) {
 			case 'j': ptype = pkt_type_json; break;
 			case 'T': test = true; break;
 			case 's': host = argv[++i]; host_arg = true; break;
-			case 'k': key = argv[++i]; break;
+			case 'k': key = argv[++i]; key_arg = true; break;
 			case 'K': keypair_seed_str = argv[++i]; break;
 			case 'p': port = argv[++i]; port_arg = true; break;
 			case 'u': socket_path = argv[++i]; break;
@@ -931,27 +957,33 @@ int main(int argc, char *argv[]) {
 		memcpy(remote_key, public_key, 32);
 	}
 
+	bool implied_tcp = host_arg || port_arg;
+	bool implied_auth = key_arg || keypair_seed_str || shs_cap_key_str_arg || test;
+
 	if (test) {
 		infd = STDIN_FILENO;
 		outfd = STDOUT_FILENO;
 		s = -1;
 
 	} else if (socket_path) {
-		if (port_arg) errx(1, "-p port conflicts with -u socket_path");
-		if (host_arg) errx(1, "-s host conflicts with -u socket_path");
-		struct sockaddr_un name;
-		size_t path_len = strlen(socket_path);
-		if (path_len >= sizeof(name.sun_path)-1) errx(1, "socket path too long");
-		s = socket(AF_UNIX, SOCK_STREAM, 0);
-		if (s < 0) err(1, "socket");
-		memset(&name, 0, sizeof(struct sockaddr_un));
-		name.sun_family = AF_UNIX;
-		strncpy(name.sun_path, socket_path, sizeof(name.sun_path) - 1);
-		rc = connect(s, (const struct sockaddr *)&name, sizeof name);
-		if (rc < 0) err(1, "connect");
+		if (implied_tcp) errx(1, "-u option conflicts with -s and -p options");
+		s = unix_connect(socket_path);
+		if (s < 0) err(1, "unix_connect");
+		infd = outfd = s;
+
+	} else if (!implied_tcp && !implied_auth) {
+		char socket_path_buf[_POSIX_PATH_MAX];
+		rc = get_socket_path(socket_path_buf, sizeof(socket_path_buf), app_dir);
+		if (rc < 0 && noauth) err(1, "get_socket_path");
+		if (rc < 0) goto do_tcp_connect;
+		s = unix_connect(socket_path_buf);
+		if (s < 0 && noauth) err(1, "unix_connect");
+		if (s < 0) goto do_tcp_connect;
+		noauth = true;
 		infd = outfd = s;
 
 	} else {
+do_tcp_connect:
 		s = tcp_connect(host, port);
 		if (s < 0) err(1, "tcp_connect");
 		infd = outfd = s;
@@ -961,10 +993,7 @@ int main(int argc, char *argv[]) {
 	if (noauth) {
 		bs.s = s;
 		bs.noauth = true;
-		if (key) errx(1, "-k keypair_seed conflicts with -n (noauth)");
-		if (keypair_seed_str) errx(1, "-K keypair_seed conflicts with -n (noauth)");
-		if (shs_cap_key_str_arg) errx(1, "-c cap_key conflicts with -n (noauth)");
-		if (test) errx(1, "-n (noauth) conflicts with -T (test shs)");
+		if (implied_auth) errx(1, "-n option conflicts with -k, -K, -c and -T options.");
 	} else {
 		shs_connect(s, infd, outfd, public_key, private_key, shs_cap_key, remote_key, &bs);
 	}