try to keep channels open until an exit-status message is sent.

don't kill the login shells if the shells stdin/out/err is closed.
this should now work:
ssh -2n localhost 'exec > /dev/null 2>&1; sleep 10; exit 5'; echo ?

7 files changed, 83 insertions, 78 deletions

diff --git a/usr.bin/ssh/channels.c b/usr.bin/ssh/channels.c
index 4f7f33b685d..3e7ba4c7e28 100644
--- a/usr.bin/ssh/channels.c
+++ b/usr.bin/ssh/channels.c
@@ -39,7 +39,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: channels.c,v 1.139 2001/10/09 21:59:41 markus Exp $");
+RCSID("$OpenBSD: channels.c,v 1.140 2001/10/10 22:18:47 markus Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -331,10 +331,6 @@ channel_free(Channel *c)
 	debug3("channel_free: status: %s", s);
 	xfree(s);
 
-	if (c->detach_user != NULL) {
-		debug("channel_free: channel %d: detaching channel user", c->self);
-		c->detach_user(c->self, NULL);
-	}
 	if (c->sock != -1)
 		shutdown(c->sock, SHUT_RDWR);
 	channel_close_fds(c);
@@ -1520,6 +1516,28 @@ channel_handler_init(void)
 		channel_handler_init_15();
 }
 
+/* gc dead channels */
+static void
+channel_garbage_collect(Channel *c)
+{
+	if (c == NULL)
+		return;
+	if (c->detach_user != NULL) {
+		if (!chan_is_dead(c, 0))
+			return;
+		debug("channel %d: gc: notify user", c->self);
+		c->detach_user(c->self, NULL);
+		/* if we still have a callback */
+		if (c->detach_user != NULL)
+			return;
+		debug("channel %d: gc: user detached", c->self);
+	}
+	if (!chan_is_dead(c, 1))
+		return;
+	debug("channel %d: garbage collecting", c->self);
+	channel_free(c);
+}
+
 static void
 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
 {
@@ -1537,24 +1555,7 @@ channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
 			continue;
 		if (ftab[c->type] != NULL)
 			(*ftab[c->type])(c, readset, writeset);
-		if (chan_is_dead(c)) {
-			/*
-			 * we have to remove the fd's from the select mask
-			 * before the channels are free'd and the fd's are
-			 * closed
-			 */
-			if (c->wfd != -1)
-				FD_CLR(c->wfd, writeset);
-			if (c->rfd != -1)
-				FD_CLR(c->rfd, readset);
-			if (c->efd != -1) {
-				if (c->extended_usage == CHAN_EXTENDED_READ)
-					FD_CLR(c->efd, readset);
-				if (c->extended_usage == CHAN_EXTENDED_WRITE)
-					FD_CLR(c->efd, writeset);
-			}
-			channel_free(c);
-		}
+		channel_garbage_collect(c);
 	}
 }
 
@@ -1625,7 +1626,7 @@ channel_output_poll()
 		if (compat20 &&
 		    (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
 			/* XXX is this true? */
-			debug2("channel %d: no data after CLOSE", c->self);
+			debug3("channel %d: will not send data after close", c->self);
 			continue;
 		}
 
diff --git a/usr.bin/ssh/channels.h b/usr.bin/ssh/channels.h
index 090d2ca6e64..89e48009dd5 100644
--- a/usr.bin/ssh/channels.h
+++ b/usr.bin/ssh/channels.h
@@ -32,7 +32,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
-/* RCSID("$OpenBSD: channels.h,v 1.49 2001/10/09 21:59:41 markus Exp $"); */
+/* RCSID("$OpenBSD: channels.h,v 1.50 2001/10/10 22:18:47 markus Exp $"); */
 
 #ifndef CHANNEL_H
 #define CHANNEL_H
@@ -214,7 +214,7 @@ void	 auth_input_open_request(int, int, void *);
 
 /* channel close */
 
-int	 chan_is_dead(Channel *);
+int	 chan_is_dead(Channel *, int);
 void	 chan_mark_dead(Channel *);
 void 	 chan_init_iostates(Channel *);
 void	 chan_init(void);
diff --git a/usr.bin/ssh/clientloop.c b/usr.bin/ssh/clientloop.c
index e6da67d51a0..43332d1f4a1 100644
--- a/usr.bin/ssh/clientloop.c
+++ b/usr.bin/ssh/clientloop.c
@@ -59,7 +59,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: clientloop.c,v 1.82 2001/09/17 20:52:47 markus Exp $");
+RCSID("$OpenBSD: clientloop.c,v 1.83 2001/10/10 22:18:47 markus Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -753,6 +753,7 @@ client_channel_closed(int id, void *arg)
 	if (id != session_ident)
 		error("client_channel_closed: id %d != session_ident %d",
 		    id, session_ident);
+	channel_cancel_cleanup(id);
 	session_closed = 1;
 	if (in_raw_mode())
 		leave_raw_mode();
diff --git a/usr.bin/ssh/nchan.c b/usr.bin/ssh/nchan.c
index 1dd9eab4991..08f38b02e21 100644
--- a/usr.bin/ssh/nchan.c
+++ b/usr.bin/ssh/nchan.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: nchan.c,v 1.31 2001/07/17 21:04:57 markus Exp $");
+RCSID("$OpenBSD: nchan.c,v 1.32 2001/10/10 22:18:47 markus Exp $");
 
 #include "ssh1.h"
 #include "ssh2.h"
@@ -432,7 +432,7 @@ chan_mark_dead(Channel *c)
 }
 
 int
-chan_is_dead(Channel *c)
+chan_is_dead(Channel *c, int send)
 {
 	if (c->type == SSH_CHANNEL_ZOMBIE) {
 		debug("channel %d: zombie", c->self);
@@ -461,7 +461,16 @@ chan_is_dead(Channel *c)
 		       "read": "write");
 	} else {
 		if (!(c->flags & CHAN_CLOSE_SENT)) {
-			chan_send_close2(c);
+			if (send) {
+				chan_send_close2(c);
+			} else {
+				/* channel would be dead if we sent a close */
+				if (c->flags & CHAN_CLOSE_RCVD) {
+					debug("channel %d: almost dead",
+					    c->self);
+					return 1;
+				}
+			}
 		}
 		if ((c->flags & CHAN_CLOSE_SENT) &&
 		    (c->flags & CHAN_CLOSE_RCVD)) {
diff --git a/usr.bin/ssh/serverloop.c b/usr.bin/ssh/serverloop.c
index 94886dbadd1..5976d51df1e 100644
--- a/usr.bin/ssh/serverloop.c
+++ b/usr.bin/ssh/serverloop.c
@@ -35,7 +35,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: serverloop.c,v 1.81 2001/10/09 21:59:41 markus Exp $");
+RCSID("$OpenBSD: serverloop.c,v 1.82 2001/10/10 22:18:47 markus Exp $");
 
 #include "xmalloc.h"
 #include "packet.h"
@@ -208,9 +208,6 @@ wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
 		max_time_milliseconds = options.client_alive_interval * 1000;
 	}
 
-	/* When select fails we restart from here. */
-retry_select:
-
 	/* Allocate and update select() masks for channel descriptors. */
 	channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, 0);
 
@@ -275,12 +272,11 @@ retry_select:
 	ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
 
 	if (ret == -1) {
+		memset(*readsetp, 0, *maxfdp);
+		memset(*writesetp, 0, *maxfdp);
 		if (errno != EINTR)
 			error("select: %.100s", strerror(errno));
-		else
-			goto retry_select;
-	}
-	if (ret == 0 && client_alive_scheduled)
+	} else if (ret == 0 && client_alive_scheduled)
 		client_alive_check();
 }
 
@@ -668,13 +664,30 @@ server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
 	/* NOTREACHED */
 }
 
+static void
+collect_children(void)
+{
+	pid_t pid;
+	sigset_t oset, nset;
+	int status;
+
+	/* block SIGCHLD while we check for dead children */
+	sigemptyset(&nset);
+	sigaddset(&nset, SIGCHLD);
+	sigprocmask(SIG_BLOCK, &nset, &oset);
+	if (child_terminated) {
+		while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
+			session_close_by_pid(pid, status);
+		child_terminated = 0;
+	}
+	sigprocmask(SIG_SETMASK, &oset, NULL);
+}
+
 void
 server_loop2(Authctxt *authctxt)
 {
 	fd_set *readset = NULL, *writeset = NULL;
-	int rekeying = 0, max_fd, status, nalloc = 0;
-	pid_t pid;
-	sigset_t oset, nset;
+	int rekeying = 0, max_fd, nalloc = 0;
 
 	debug("Entering interactive session for SSH2.");
 
@@ -698,16 +711,7 @@ server_loop2(Authctxt *authctxt)
 		wait_until_can_do_something(&readset, &writeset, &max_fd,
 		    &nalloc, 0);
 
-		/* block SIGCHLD while we check for dead children */
-		sigemptyset(&nset);
-		sigaddset(&nset, SIGCHLD);
-		sigprocmask(SIG_BLOCK, &nset, &oset);
-		if (child_terminated) {
-			while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
-				session_close_by_pid(pid, status);
-			child_terminated = 0;
-		}
-		sigprocmask(SIG_SETMASK, &oset, NULL);
+		collect_children();
 		if (!rekeying)
 			channel_after_select(readset, writeset);
 		process_input(readset);
@@ -715,6 +719,8 @@ server_loop2(Authctxt *authctxt)
 			break;
 		process_output(writeset);
 	}
+	collect_children();
+
 	if (readset)
 		xfree(readset);
 	if (writeset)
@@ -723,13 +729,8 @@ server_loop2(Authctxt *authctxt)
 	/* free all channels, no more reads and writes */
 	channel_free_all();
 
-	/* collect remaining dead children, XXX not necessary? */
-	signal(SIGCHLD, SIG_DFL);
-	while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
-		session_close_by_pid(pid, status);
-
-	/* close remaining sessions, e.g remove wtmp entries */
-	session_close_all();
+	/* free remaining sessions, e.g. remove wtmp entries */
+	session_destroy_all();
 }
 
 static void
diff --git a/usr.bin/ssh/session.c b/usr.bin/ssh/session.c
index fa68c391732..b1d49314249 100644
--- a/usr.bin/ssh/session.c
+++ b/usr.bin/ssh/session.c
@@ -33,7 +33,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: session.c,v 1.106 2001/10/09 21:59:41 markus Exp $");
+RCSID("$OpenBSD: session.c,v 1.107 2001/10/10 22:18:47 markus Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -1576,36 +1576,29 @@ session_close_by_channel(int id, void *arg)
 {
 	Session *s = session_by_channel(id);
 	if (s == NULL) {
-		debug("session_close_by_channel: no session for channel %d", id);
+		debug("session_close_by_channel: no session for id %d", id);
 		return;
 	}
-	/* disconnect channel */
-	channel_cancel_cleanup(s->chanid);
-	s->chanid = -1;
-
-	debug("session_close_by_channel: channel %d kill %d", id, s->pid);
+	debug("session_close_by_channel: channel %d child %d", id, s->pid);
 	if (s->pid != 0) {
-		/* notify child */
-		if (kill(s->pid, SIGHUP) < 0)
-			error("session_close_by_channel: kill %d: %s",
-			    s->pid, strerror(errno));
+		/* delay detach */
+		debug("session_close_by_channel: channel %d: has child", id);
+		return;
 	}
+	/* detach by removing callback */
+	channel_cancel_cleanup(s->chanid);
+	s->chanid = -1;
 	session_close(s);
 }
 
 void
-session_close_all(void)
+session_destroy_all(void)
 {
 	int i;
 	for(i = 0; i < MAX_SESSIONS; i++) {
 		Session *s = &sessions[i];
-		if (s->used) {
-			if (s->chanid != -1) {
-				channel_cancel_cleanup(s->chanid);
-				s->chanid = -1;
-			}
+		if (s->used) 
 			session_close(s);
-		}
 	}
 }
 
diff --git a/usr.bin/ssh/session.h b/usr.bin/ssh/session.h
index d2b0d936409..6d5b8e69922 100644
--- a/usr.bin/ssh/session.h
+++ b/usr.bin/ssh/session.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: session.h,v 1.12 2001/10/09 21:59:41 markus Exp $	*/
+/*	$OpenBSD: session.h,v 1.13 2001/10/10 22:18:47 markus Exp $	*/
 
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
@@ -32,6 +32,6 @@ int	 session_open(Authctxt*, int);
 void	 session_input_channel_req(int, void *);
 void	 session_close_by_pid(pid_t, int);
 void	 session_close_by_channel(int, void *);
-void	 session_close_all(void);
+void	 session_destroy_all(void);
 
 #endif