Add RemoteCommand option to specify a command in the ssh config

file instead of giving it on the client's command line.  This command
will be executed on the remote host.  The feature allows to automate
tasks using ssh config.
OK markus@

1 files changed, 32 insertions, 8 deletions

diff --git a/usr.bin/ssh/ssh.c b/usr.bin/ssh/ssh.c
index 2cb6a1d4b19..61fbd28a44a 100644
--- a/usr.bin/ssh/ssh.c
+++ b/usr.bin/ssh/ssh.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh.c,v 1.460 2017/05/30 08:52:19 markus Exp $ */
+/* $OpenBSD: ssh.c,v 1.461 2017/05/30 18:58:37 bluhm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -942,12 +942,6 @@ main(int ac, char **av)
 		}
 	}
 
-	/* Cannot fork to background if no command. */
-	if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
-	    !no_shell_flag)
-		fatal("Cannot fork into background without a command "
-		    "to execute.");
-
 	/*
 	 * Initialize "log" output.  Since we are the client all output
 	 * goes to stderr unless otherwise specified by -y or -E.
@@ -1101,6 +1095,15 @@ main(int ac, char **av)
 	if (original_effective_uid != 0)
 		options.use_privileged_port = 0;
 
+	if (buffer_len(&command) != 0 && options.remote_command != NULL)
+		fatal("Cannot execute command-line and remote command.");
+
+	/* Cannot fork to background if no command. */
+	if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
+	    options.remote_command == NULL && !no_shell_flag)
+		fatal("Cannot fork into background without a command "
+		    "to execute.");
+
 	/* reinit */
 	log_init(argv0, options.log_level, options.log_facility, !use_syslog);
 
@@ -1109,7 +1112,7 @@ main(int ac, char **av)
 		tty_flag = 1;
 
 	/* Allocate a tty by default if no command specified. */
-	if (buffer_len(&command) == 0)
+	if (buffer_len(&command) == 0 && options.remote_command == NULL)
 		tty_flag = options.request_tty != REQUEST_TTY_NO;
 
 	/* Force no tty */
@@ -1163,6 +1166,27 @@ main(int ac, char **av)
 		free(cp);
 	}
 
+	if (options.remote_command != NULL) {
+		debug3("expanding RemoteCommand: %s", options.remote_command);
+		cp = options.remote_command;
+		options.remote_command = percent_expand(cp,
+		    "C", conn_hash_hex,
+		    "L", shorthost,
+		    "d", pw->pw_dir,
+		    "h", host,
+		    "l", thishost,
+		    "n", host_arg,
+		    "p", portstr,
+		    "r", options.user,
+		    "u", pw->pw_name,
+		    (char *)NULL);
+		debug3("expanded RemoteCommand: %s", options.remote_command);
+		free(cp);
+		buffer_append(&command, options.remote_command,
+		    strlen(options.remote_command));
+
+	}
+
 	if (options.control_path != NULL) {
 		cp = tilde_expand_filename(options.control_path,
 		    original_real_uid);