- markus@cvs.openbsd.org 2001/10/09 21:59:41

[channels.c channels.h serverloop.c session.c session.h]
     simplify session close: no more delayed session_close, no more blocking wait() calls.

ChangeLog

@@ -44,6 +44,10 @@
      [serverloop.c]
      close all channels if the connection to the remote host has been closed,
      should fix sshd's hanging with WCHAN==wait
+   - markus@cvs.openbsd.org 2001/10/09 21:59:41
+     [channels.c channels.h serverloop.c session.c session.h]
+     simplify session close: no more delayed session_close, no more 
+     blocking wait() calls.
 
 20011007
  - (bal) ssh-copy-id corrected permissions for .ssh/ and authorized_keys.
@@ -6689,4 +6693,4 @@
  - Wrote replacements for strlcpy and mkdtemp
  - Released 1.0pre1
 
-$Id: ChangeLog,v 1.1597 2001/10/10 05:08:36 djm Exp $
+$Id: ChangeLog,v 1.1598 2001/10/10 05:14:37 djm Exp $

channels.c

@@ -39,7 +39,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: channels.c,v 1.138 2001/10/08 11:48:57 markus Exp $");
+RCSID("$OpenBSD: channels.c,v 1.139 2001/10/09 21:59:41 markus Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -359,22 +359,6 @@ channel_free_all(void)
 			channel_free(channels[i]);
 }
 
-void
-channel_detach_all(void)
-{
-	int i;
-	Channel *c;
-
-	for (i = 0; i < channels_alloc; i++) {
-		c = channels[i];
-		if (c != NULL && c->detach_user != NULL) {
-			debug("channel_detach_all: channel %d", c->self);
-			c->detach_user(c->self, NULL);
-			c->detach_user = NULL;
-		}
-	}
-}
-
 /*
  * Closes the sockets/fds of all channels.  This is used to close extra file
  * descriptors after a fork.

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 1.48 2001/10/07 17:49:40 markus Exp $"); */
+/* RCSID("$OpenBSD: channels.h,v 1.49 2001/10/09 21:59:41 markus Exp $"); */
 
 #ifndef CHANNEL_H
 #define CHANNEL_H
@@ -143,7 +143,6 @@ Channel *channel_new(char *, int, int, int, int, int, int, int, char *, int);
 void	 channel_set_fds(int, int, int, int, int, int);
 void	 channel_free(Channel *);
 void	 channel_free_all(void);
-void	 channel_detach_all(void);
 void	 channel_stop_listening(void);
 
 void	 channel_send_open(int);
@@ -177,7 +176,6 @@ void     channel_output_poll(void);
 
 int      channel_not_very_much_buffered_data(void);
 void     channel_close_all(void);
-void     channel_free_all(void);
 int      channel_still_open(void);
 char	*channel_open_message(void);
 int	 channel_find_open(void);

serverloop.c

@@ -35,7 +35,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: serverloop.c,v 1.80 2001/10/09 19:51:18 markus Exp $");
+RCSID("$OpenBSD: serverloop.c,v 1.81 2001/10/09 21:59:41 markus Exp $");
 
 #include "xmalloc.h"
 #include "packet.h"
@@ -674,6 +674,7 @@ 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;
 
 	debug("Entering interactive session for SSH2.");
 
@@ -696,12 +697,17 @@ server_loop2(Authctxt *authctxt)
 			channel_output_poll();
 		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);
-			/* XXX race */
 			child_terminated = 0;
 		}
+		sigprocmask(SIG_SETMASK, &oset, NULL);
 		if (!rekeying)
 			channel_after_select(readset, writeset);
 		process_input(readset);
@@ -709,35 +715,21 @@ server_loop2(Authctxt *authctxt)
 			break;
 		process_output(writeset);
 	}
-	/* close all channels, no more reads and writes */
-	channel_close_all();
-
 	if (readset)
 		xfree(readset);
 	if (writeset)
 		xfree(writeset);
 
-	mysignal(SIGCHLD, SIG_DFL);
+	/* free all channels, no more reads and writes */
+	channel_free_all();
 
-	/* collect dead children */
+	/* collect remaining dead children, XXX not necessary? */
+	mysignal(SIGCHLD, SIG_DFL);
 	while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
 		session_close_by_pid(pid, status);
-	/*
-	 * there is a race between channel_detach_all() killing remaining
-	 * children and children dying before kill()
-	 */
-	channel_detach_all();
 
-	while (session_have_children()) {
+	/* close remaining sessions, e.g remove wtmp entries */
-		pid = waitpid(-1, &status, 0);
+	session_close_all();
-		if (pid > 0)
-			session_close_by_pid(pid, status);
-		else {
-			error("waitpid returned %d: %s", pid, strerror(errno));
-			break;
-		}
-	}
-	channel_free_all();
 }
 
 static void

session.c

@@ -33,7 +33,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: session.c,v 1.105 2001/10/09 19:32:49 markus Exp $");
+RCSID("$OpenBSD: session.c,v 1.106 2001/10/09 21:59:41 markus Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -1949,22 +1949,6 @@ session_close_by_pid(pid_t pid, int status)
 	session_close(s);
 }
 
-int
-session_have_children(void)
-{
-	int i;
-
-	for(i = 0; i < MAX_SESSIONS; i++) {
-		Session *s = &sessions[i];
-		if (s->used && s->pid != -1) {
-			debug("session_have_children: id %d pid %d", i, s->pid);
-			return 1;
-		}
-	}
-	debug("session_have_children: no more children");
-	return 0;
-}
-
 /*
  * this is called when a channel dies before
  * the session 'child' itself dies
@@ -1982,15 +1966,29 @@ session_close_by_channel(int id, void *arg)
 	s->chanid = -1;
 
 	debug("session_close_by_channel: channel %d kill %d", id, s->pid);
-	if (s->pid == 0) {
+	if (s->pid != 0) {
-		/* close session immediately */
+		/* notify child */
-		session_close(s);
+		if (kill(s->pid, SIGHUP) < 0)
-	} else {
-		/* notify child, delay session cleanup */
-		if (kill(s->pid, (s->ttyfd == -1) ? SIGTERM : SIGHUP) < 0)
 			error("session_close_by_channel: kill %d: %s",
 			    s->pid, strerror(errno));
 	}
+	session_close(s);
+}
+
+void
+session_close_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;
+			}
+			session_close(s);
+		}
+	}
 }
 
 static char *

session.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: session.h,v 1.11 2001/07/02 13:59:15 markus Exp $	*/
+/*	$OpenBSD: session.h,v 1.12 2001/10/09 21:59:41 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 *);
-int	 session_have_children(void);
+void	 session_close_all(void);
 
 #endif