Dear OpenSSH developers,
Volker Diels-Grabsch schrieb:
> So how should such an option be named? I propose:
>
> default == ExecRemoteCommand yes
> -N == ExecRemoteCommand no
>
> Does that make sense?
I just went ahead and created a patch for OpenSSH. It would be great
if somebody could review this. I took extra care to meet your high
quality standards.
BTW, I wonder whether the folloing save-flags can be removed:
- "oexec_remote_command" (formerly "ono_shell_flag")
- "orequest_tty"
To my understanding, keeping "otty_flag" should be sufficient.
Regards,
Volker
--
Volker Diels-Grabsch
----<<<((()))>>>----
Author: Volker Diels-Grabsch <v@xxxxxx>
Add ssh_config option ExecRemoteCommand which is equivalent to -N
The man page of ssh_config is adjusted accordingly.
A new flag "option.exec_remote_command" is introduced which replaces
the former CLI-only "no_shell_flag", but has the inverse meaning.
The "ono_shell_flag" is renamed to "oexec_remote_command" and mirrors
"option.exec_remote_command" instead of "no_shell_flag".
A potential pitfall is fixed: Until now, the code had to ensure that
whenever "no_shell_flag" is set, the "option.request_tty" must be set
to "no". Now, this is no longer required. Instead, it is ensured at
one central place that the "tty_flag" is always calculated correctly
from "option.request_tty" and "option.exec_remote_command".
In "clientloop.c" some dead code regarding "no_shell_flag" is removed.
diff --git a/clientloop.c b/clientloop.c
index 2c44f5d..732638f 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -120,9 +120,6 @@ extern Options options;
/* Flag indicating that stdin should be redirected from /dev/null. */
extern int stdin_null_flag;
-/* Flag indicating that no shell has been requested */
-extern int no_shell_flag;
-
/* Flag indicating that ssh should daemonise after authentication is complete */
extern int fork_after_authentication_flag;
@@ -1739,7 +1736,7 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
* exit status to be returned. In that case, clear error code if the
* connection was deliberately terminated at this end.
*/
- if (no_shell_flag && received_signal == SIGTERM) {
+ if (!options.exec_remote_command && received_signal == SIGTERM) {
received_signal = 0;
exit_status = 0;
}
@@ -2712,7 +2709,7 @@ client_stop_mux(void)
* If we are in persist mode, or don't have a shell, signal that we
* should close when all active channels are closed.
*/
- if (options.control_persist || no_shell_flag) {
+ if (options.control_persist || !options.exec_remote_command) {
session_closed = 1;
setproctitle("[stopped mux]");
}
diff --git a/readconf.c b/readconf.c
index c177202..7e7e200 100644
--- a/readconf.c
+++ b/readconf.c
@@ -166,6 +166,7 @@ typedef enum {
oTunnel, oTunnelDevice, oLocalCommand, oPermitLocalCommand,
oVisualHostKey,
oKexAlgorithms, oIPQoS, oRequestTTY, oIgnoreUnknown, oProxyUseFdpass,
+ oExecRemoteCommand,
oCanonicalDomains, oCanonicalizeHostname, oCanonicalizeMaxDots,
oCanonicalizeFallbackLocal, oCanonicalizePermittedCNAMEs,
oStreamLocalBindMask, oStreamLocalBindUnlink, oRevokedHostKeys,
@@ -282,6 +283,7 @@ static struct {
{ "ipqos", oIPQoS },
{ "requesttty", oRequestTTY },
{ "proxyusefdpass", oProxyUseFdpass },
+ { "execremotecommand", oExecRemoteCommand },
{ "canonicaldomains", oCanonicalDomains },
{ "canonicalizefallbacklocal", oCanonicalizeFallbackLocal },
{ "canonicalizehostname", oCanonicalizeHostname },
@@ -1547,6 +1549,10 @@ parse_keytypes:
intptr = &options->proxy_use_fdpass;
goto parse_flag;
+ case oExecRemoteCommand:
+ intptr = &options->exec_remote_command;
+ goto parse_flag;
+
case oCanonicalDomains:
value = options->num_canonical_domains != 0;
while ((arg = strdelim(&s)) != NULL && *arg != '\0') {
@@ -1847,6 +1853,7 @@ initialize_options(Options * options)
options->ip_qos_bulk = -1;
options->request_tty = -1;
options->proxy_use_fdpass = -1;
+ options->exec_remote_command = -1;
options->ignored_unknown = NULL;
options->num_canonical_domains = 0;
options->num_permitted_cnames = 0;
@@ -2035,6 +2042,8 @@ fill_default_options(Options * options)
options->request_tty = REQUEST_TTY_AUTO;
if (options->proxy_use_fdpass == -1)
options->proxy_use_fdpass = 0;
+ if (options->exec_remote_command == -1)
+ options->exec_remote_command = 1;
if (options->canonicalize_max_dots == -1)
options->canonicalize_max_dots = 1;
if (options->canonicalize_fallback_local == -1)
@@ -2521,6 +2530,7 @@ dump_client_config(Options *o, const char *host)
dump_cfg_fmtint(oPermitLocalCommand, o->permit_local_command);
dump_cfg_fmtint(oProtocol, o->protocol);
dump_cfg_fmtint(oProxyUseFdpass, o->proxy_use_fdpass);
+ dump_cfg_fmtint(oExecRemoteCommand, o->exec_remote_command);
dump_cfg_fmtint(oPubkeyAuthentication, o->pubkey_authentication);
dump_cfg_fmtint(oRequestTTY, o->request_tty);
dump_cfg_fmtint(oRhostsRSAAuthentication, o->rhosts_rsa_authentication);
diff --git a/readconf.h b/readconf.h
index cef55f7..7d2b6a8 100644
--- a/readconf.h
+++ b/readconf.h
@@ -146,6 +146,8 @@ typedef struct {
int proxy_use_fdpass;
+ int exec_remote_command;
+
int num_canonical_domains;
char *canonical_domains[MAX_CANON_DOMAINS];
int canonicalize_hostname;
diff --git a/ssh.c b/ssh.c
index 03a23fb..fdb1335 100644
--- a/ssh.c
+++ b/ssh.c
@@ -127,9 +127,6 @@ int debug_flag = 0;
/* Flag indicating whether a tty should be requested */
int tty_flag = 0;
-/* don't exec a shell */
-int no_shell_flag = 0;
-
/*
* Flag indicating that nothing should be read from stdin. This can be set
* on the command line.
@@ -143,7 +140,7 @@ int stdin_null_flag = 0;
int need_controlpersist_detach = 0;
/* Copies of flags for ControlPersist foreground slave */
-int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
+int ostdin_null_flag, oexec_remote_command, otty_flag, orequest_tty;
/*
* Flag indicating that ssh should fork after authentication. This is useful
@@ -797,8 +794,7 @@ main(int ac, char **av)
optarg);
exit(255);
}
- options.request_tty = REQUEST_TTY_NO;
- no_shell_flag = 1;
+ options.exec_remote_command = 0;
break;
case 'q':
options.log_level = SYSLOG_LEVEL_QUIET;
@@ -905,8 +901,7 @@ main(int ac, char **av)
options.compression = 1;
break;
case 'N':
- no_shell_flag = 1;
- options.request_tty = REQUEST_TTY_NO;
+ options.exec_remote_command = 0;
break;
case 'T':
options.request_tty = REQUEST_TTY_NO;
@@ -995,7 +990,7 @@ main(int ac, char **av)
/* Cannot fork to background if no command. */
if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
- !no_shell_flag)
+ options.exec_remote_command)
fatal("Cannot fork into background without a command "
"to execute.");
@@ -1164,6 +1159,8 @@ main(int ac, char **av)
/* Force no tty */
if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
tty_flag = 0;
+ if (!options.exec_remote_command)
+ tty_flag = 0;
/* Do not allocate a tty if stdin is not a tty. */
if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
options.request_tty != REQUEST_TTY_FORCE) {
@@ -1935,7 +1932,7 @@ ssh_session2_open(void)
debug3("ssh_session2_open: channel_new: %d", c->self);
channel_send_open(c->self);
- if (!no_shell_flag)
+ if (options.exec_remote_command)
channel_register_open_confirm(c->self,
ssh_session2_setup, NULL);
@@ -1966,11 +1963,11 @@ ssh_session2(void)
*/
if (options.control_persist && muxserver_sock != -1) {
ostdin_null_flag = stdin_null_flag;
- ono_shell_flag = no_shell_flag;
+ oexec_remote_command = options.exec_remote_command;
orequest_tty = options.request_tty;
otty_flag = tty_flag;
stdin_null_flag = 1;
- no_shell_flag = 1;
+ options.exec_remote_command = 0;
tty_flag = 0;
if (!fork_after_authentication_flag)
need_controlpersist_detach = 1;
@@ -1983,7 +1980,7 @@ ssh_session2(void)
if (options.control_persist && muxserver_sock == -1)
ssh_init_stdio_forwarding();
- if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
+ if (options.exec_remote_command || (datafellows & SSH_BUG_DUMMYCHAN))
id = ssh_session2_open();
else {
packet_set_interactive(
diff --git a/ssh_config.5 b/ssh_config.5
index 7630e7b..4962dce 100644
--- a/ssh_config.5
+++ b/ssh_config.5
@@ -706,6 +706,13 @@ followed by a letter, or
to disable the escape
character entirely (making the connection transparent for binary
data).
+.It Cm ExecRemoteCommand
+Specifies whether to execute a remote command.
+This option can be set to
+.Dq no
+for just forwarding ports.
+The default is
+.Dq yes .
.It Cm ExitOnForwardFailure
Specifies whether
.Xr ssh 1
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