openssh unix dev - Dec 2007 - sshd's -e doesn't work as expected

Hello,

I'm running a sshd server using the -e flag so that I can capture its
whole output and later send it to the user.  I'm also setting LogLevel
to DEBUG1 in the configuration file and I don't want to disturb syslogd.
But the problem is that it doesn't work as expected (or as I expect,
which I think should be the correct behavior).  The log file ends up
being empty because the call to daemon(0, 0) done by the server
effectively closes the stderr stream and all prints to it do not work.

I've fixed this issue with the attached patch.  Hope that it is OK and
can be committed.  If not, please tell me why.

Thank you,

Index: sshd.c
==================================================================RCS file:
/cvsroot/src/crypto/dist/ssh/sshd.c,v
retrieving revision 1.42
diff -u -p -r1.42 sshd.c
--- sshd.c	18 Dec 2007 02:35:33 -0000	1.42
+++ sshd.c	26 Dec 2007 20:12:22 -0000
@@ -1485,8 +1485,16 @@ main(int ac, char **av)
 	if (!(debug_flag || inetd_flag || no_daemon_flag)) {
 		int fd;
 
-		if (daemon(0, 0) < 0)
+		if (daemon(0, 1) < 0)
 			fatal("daemon() failed: %.200s", strerror(errno));
+		close(STDIN_FILENO);
+		open(_PATH_DEVNULL, O_RDONLY);
+		close(STDOUT_FILENO);
+		open(_PATH_DEVNULL, O_WRONLY);
+		if (!log_stderr) {
+			close(STDERR_FILENO);
+			open(_PATH_DEVNULL, O_WRONLY);
+		}
 
 		/* Disconnect from the controlling tty. */
 		fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);

-- 
Julio M. Merino Vidal <jmmv at NetBSD.org>

I think the intent was for '-e' to be used with '-D':

__________[from sshd(8)]__________

-D      When this option is specified, sshd will not detach and
        does not become a daemon.  This allows easy monitoring of sshd.

__________[end sshd(8)]__________

Perhaps sshd should complain if '-e' appears without '-D'?

--jim

Circa 2007-12-26 15:15 dixit Julio M. Merino Vidal:

: Hello,
: 
: I'm running a sshd server using the -e flag so that I can capture its
: whole output and later send it to the user.  I'm also setting LogLevel
: to DEBUG1 in the configuration file and I don't want to disturb syslogd.
: But the problem is that it doesn't work as expected (or as I expect,
: which I think should be the correct behavior).  The log file ends up
: being empty because the call to daemon(0, 0) done by the server
: effectively closes the stderr stream and all prints to it do not work.
: 
: I've fixed this issue with the attached patch.  Hope that it is OK and
: can be committed.  If not, please tell me why.
: 
: Thank you,
: 
: Index: sshd.c
: ==================================================================: RCS file:
/cvsroot/src/crypto/dist/ssh/sshd.c,v
: retrieving revision 1.42
: diff -u -p -r1.42 sshd.c
: --- sshd.c	18 Dec 2007 02:35:33 -0000	1.42
: +++ sshd.c	26 Dec 2007 20:12:22 -0000
: @@ -1485,8 +1485,16 @@ main(int ac, char **av)
:  	if (!(debug_flag || inetd_flag || no_daemon_flag)) {
:  		int fd;
:  
: -		if (daemon(0, 0) < 0)
: +		if (daemon(0, 1) < 0)
:  			fatal("daemon() failed: %.200s", strerror(errno));
: +		close(STDIN_FILENO);
: +		open(_PATH_DEVNULL, O_RDONLY);
: +		close(STDOUT_FILENO);
: +		open(_PATH_DEVNULL, O_WRONLY);
: +		if (!log_stderr) {
: +			close(STDERR_FILENO);
: +			open(_PATH_DEVNULL, O_WRONLY);
: +		}
:  
:  		/* Disconnect from the controlling tty. */
:  		fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
: 
: -- 
: Julio M. Merino Vidal <jmmv at NetBSD.org>
: _______________________________________________
: openssh-unix-dev mailing list
: openssh-unix-dev at mindrot.org
: https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev
: 

-- 
jim knoble  |  jmknoble at pobox.com  |  http://www.pobox.com/~jmknoble/
(GnuPG key ID: 6F39C2CC  >>>>>> 
http://www.pobox.com/~jmknoble/keys/ )
(GnuPG fingerprint: 5024:D578:7CF4:5660:7269::F6F3:B919:9307:6F39:C2CC)
+----------------------------------------------------------------------+
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| nently on a war footing, or even a near-war footing.  --Aldous Huxley|
+----------------------------------------------------------------------+