diff -uprk.orig openssh-3.6.1p1.orig/ssh-agent.1 openssh-3.6.1p1/ssh-agent.1
--- openssh-3.6.1p1.orig/ssh-agent.1	2003-04-01 15:42:14 +0400
+++ openssh-3.6.1p1/ssh-agent.1	2003-04-11 19:09:40 +0400
@@ -45,6 +45,7 @@
 .Op Fl a Ar bind_address
 .Op Fl c Li | Fl s
 .Op Fl t Ar life
+.Op Fl u
 .Op Fl d
 .Op Ar command Op Ar args ...
 .Nm ssh-agent
@@ -95,6 +96,8 @@ A lifetime specified for an identity wit
 .Xr ssh-add 1
 overrides this value.
 Without this option the default maximum lifetime is forever.
+.It Fl u
+Run the agent in unique mode.
 .It Fl d
 Debug mode.
 When this option is specified
@@ -174,6 +177,7 @@ Contains the protocol version 2 DSA auth
 .It Pa $HOME/.ssh/id_rsa
 Contains the protocol version 2 RSA authentication identity of the user.
 .It Pa /tmp/ssh-XXXXXXXX/agent.<ppid>
+.It Pa ~/.ssh/agent
 Unix-domain sockets used to contain the connection to the
 authentication agent.
 These sockets should only be readable by the owner.
diff -uprk.orig openssh-3.6.1p1.orig/ssh-agent.c openssh-3.6.1p1/ssh-agent.c
--- openssh-3.6.1p1.orig/ssh-agent.c	2003-04-11 18:58:18 +0400
+++ openssh-3.6.1p1/ssh-agent.c	2003-04-11 19:19:53 +0400
@@ -971,6 +971,30 @@ check_parent_exists(int sig)
 	errno = save_errno;
 }
 
+static int
+check_auth_socket(const char *authsocket)
+{
+	int sock, len, ret;
+	struct sockaddr_un sunaddr;
+
+	sunaddr.sun_family = AF_UNIX;
+	strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
+#ifdef HAVE_SUN_LEN_IN_SOCKADDR_UN
+	sunaddr.sun_len = len = SUN_LEN(&sunaddr)+1;
+#else /* HAVE_SUN_LEN_IN_SOCKADDR_UN */
+	len = SUN_LEN(&sunaddr)+1;
+#endif /* HAVE_SUN_LEN_IN_SOCKADDR_UN */
+
+	sock = socket(AF_UNIX, SOCK_STREAM, 0);
+	if (sock < 0)
+		return -1;
+
+	ret = connect(sock, (struct sockaddr *) & sunaddr, len);
+	close(sock);
+
+	return ret;
+}
+
 static void
 usage(void)
 {
@@ -980,6 +1004,7 @@ usage(void)
 	fprintf(stderr, "  -c          Generate C-shell commands on stdout.\n");
 	fprintf(stderr, "  -s          Generate Bourne shell commands on stdout.\n");
 	fprintf(stderr, "  -k          Kill the current agent.\n");
+	fprintf(stderr, "  -u          Unique mode.\n");
 	fprintf(stderr, "  -d          Debug mode.\n");
 	fprintf(stderr, "  -a socket   Bind agent socket to given name.\n");
 	fprintf(stderr, "  -t life     Default identity lifetime (seconds).\n");
@@ -989,7 +1014,7 @@ usage(void)
 int
 main(int ac, char **av)
 {
-	int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
+	int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, u_flag = 0, already_running = 0;
 	int sock, fd,  ch, nalloc;
 	char *shell, *format, *pidstr, *agentsocket = NULL;
 	fd_set *readsetp = NULL, *writesetp = NULL;
@@ -997,13 +1022,10 @@ main(int ac, char **av)
 #ifdef HAVE_SETRLIMIT
 	struct rlimit rlim;
 #endif
-#ifdef HAVE_CYGWIN
 	int prev_mask;
-#endif
 	extern int optind;
 	extern char *optarg;
 	pid_t pid;
-	char pidstrbuf[1 + 3 * sizeof pid];
 
 	/* drop */
 	setegid(getgid());
@@ -1027,7 +1049,7 @@ main(int ac, char **av)
 	init_rng();
 	seed_rng();
 
-	while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
+	while ((ch = getopt(ac, av, "cdksua:t:")) != -1) {
 		switch (ch) {
 		case 'c':
 			if (s_flag)
@@ -1042,6 +1064,9 @@ main(int ac, char **av)
 				usage();
 			s_flag++;
 			break;
+		case 'u':
+			u_flag++;
+			break;
 		case 'd':
 			if (d_flag)
 				usage();
@@ -1063,7 +1088,10 @@ main(int ac, char **av)
 	ac -= optind;
 	av += optind;
 
-	if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
+	if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || u_flag))
+		usage();
+
+	if (u_flag && (k_flag || agentsocket))
 		usage();
 
 	if (ac == 0 && !c_flag && !s_flag) {
@@ -1074,19 +1102,16 @@ main(int ac, char **av)
 	if (k_flag) {
 		pidstr = getenv(SSH_AGENTPID_ENV_NAME);
 		if (pidstr == NULL) {
-			fprintf(stderr, "%s not set, cannot kill agent\n",
-			    SSH_AGENTPID_ENV_NAME);
-			exit(1);
+			fatal("%s: %s not set, cannot kill agent",
+			    __progname, SSH_AGENTPID_ENV_NAME);
 		}
 		pid = atoi(pidstr);
 		if (pid < 1) {
-			fprintf(stderr, "%s=\"%s\", which is not a good PID\n",
-			    SSH_AGENTPID_ENV_NAME, pidstr);
-			exit(1);
+			fatal("%s: %s=\"%s\", which is not a good PID",
+			    __progname, SSH_AGENTPID_ENV_NAME, pidstr);
 		}
 		if (kill(pid, SIGTERM) == -1) {
-			perror("kill");
-			exit(1);
+			fatal("%s: kill: %s", __progname, strerror(errno));
 		}
 		format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
 		printf(format, SSH_AUTHSOCKET_ENV_NAME);
@@ -1096,12 +1121,17 @@ main(int ac, char **av)
 	}
 	parent_pid = getpid();
 
-	if (agentsocket == NULL) {
+	if (u_flag) {
+		struct passwd *pw = getpwuid(geteuid());
+		if (!pw)
+			fatal("%s: getpwuid: %s", __progname, strerror(errno));
+		snprintf(socket_name, sizeof socket_name, "%s/.ssh/agent", pw->pw_dir);
+	}
+	else if (agentsocket == NULL) {
 		/* Create private directory for agent socket */
 		strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir);
 		if (mkdtemp(socket_dir) == NULL) {
-			perror("mkdtemp: private socket dir");
-			exit(1);
+			fatal("%s: mkdtemp: private socket dir: %s", __progname, strerror(errno));
 		}
 		snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
 		    (long)parent_pid);
@@ -1117,27 +1147,51 @@ main(int ac, char **av)
 	 */
 	sock = socket(AF_UNIX, SOCK_STREAM, 0);
 	if (sock < 0) {
-		perror("socket");
+		error("%s: socket: %s", __progname, strerror(errno));
 		cleanup_exit(1);
 	}
 	memset(&sunaddr, 0, sizeof(sunaddr));
 	sunaddr.sun_family = AF_UNIX;
 	strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
-#ifdef HAVE_CYGWIN
 	prev_mask = umask(0177);
-#endif
 	if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) {
-		perror("bind");
-#ifdef HAVE_CYGWIN
-		umask(prev_mask);
-#endif
-		cleanup_exit(1);
+		if (u_flag && (EADDRINUSE == errno)) {
+			if (check_auth_socket(socket_name) >= 0)
+				already_running = 1;
+			else {
+				unlink(socket_name);
+				if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) {
+					error("%s: bind: %s: %s", __progname, socket_name, strerror(errno));
+					cleanup_exit(1);
+				}
+			}
+		}
+		else {
+			error("%s: bind: %s: %s", __progname, socket_name, strerror(errno));
+			cleanup_exit(1);
+		}
 	}
-#ifdef HAVE_CYGWIN
 	umask(prev_mask);
-#endif
+
+	if (already_running) {
+		close(sock);
+		if (ac == 0) {
+			format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
+			printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
+			    SSH_AUTHSOCKET_ENV_NAME);
+			exit(0);
+		}
+		if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) < 0) {
+			error("%s: setenv: %s", __progname, strerror(errno));
+			exit(1);
+		}
+		execvp(av[0], av);
+		perror(av[0]);
+		exit(1);
+	}
+
 	if (listen(sock, 128) < 0) {
-		perror("listen");
+		error("%s: listen: %s", __progname, strerror(errno));
 		cleanup_exit(1);
 	}
 
@@ -1155,10 +1209,11 @@ main(int ac, char **av)
 	}
 	pid = fork();
 	if (pid == -1) {
-		perror("fork");
+		error("%s: fork: %s", __progname, strerror(errno));
 		cleanup_exit(1);
 	}
 	if (pid != 0) {		/* Parent - execute the given command. */
+		char pidstrbuf[1 + 3 * sizeof pid];
 		close(sock);
 		snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
 		if (ac == 0) {
@@ -1172,8 +1227,7 @@ main(int ac, char **av)
 		}
 		if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
 		    setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
-			perror("setenv");
-			exit(1);
+			fatal("%s: setenv: %s", __progname, strerror(errno));
 		}
 		log_done();
 		execvp(av[0], av);
@@ -1210,7 +1264,7 @@ main(int ac, char **av)
 skip:
 	fatal_add_cleanup(cleanup_socket, NULL);
 	new_socket(AUTH_SOCKET, sock);
-	if (ac > 0) {
+	if (!u_flag && ac > 0) {
 		signal(SIGALRM, check_parent_exists);
 		alarm(10);
 	}