Mercurial > dropbear

changeset 367:c046b66b76cd channel-fix

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propagate from branch 'au.asn.ucc.matt.dropbear' (head 31dcd7a22983ef19d6c63248e415e71d292dd0ec) to branch 'au.asn.ucc.matt.dropbear.channel-fix' (head 7559a8cc4f6abe2338636f2aced3a395a79c172c)
author Matt Johnston <matt@ucc.asn.au>
date Thu, 12 Oct 2006 03:01:10 +0000
parents 59531221b846 (current diff) 49fcc9875045 (diff)
children 87ae4565679d
files
diffstat 5 files changed, 182 insertions(+), 268 deletions(-) [+]
line wrap: on
line diff
--- a/channel.h	Wed Oct 11 16:00:50 2006 +0000
+++ b/channel.h	Thu Oct 12 03:01:10 2006 +0000
@@ -73,10 +73,9 @@
 	circbuffer *extrabuf; /* extended-data for the program - used like writebuf
 					     but for stderr */
 
-	int sentclosed, recvclosed;
-
-	/* this is set when we receive/send a channel eof packet */
-	int recveof, senteof;
+	/* whether close/eof messages have been exchanged */
+	int sent_close, recv_close;
+	int recv_eof, sent_eof;
 
 	int initconn; /* used for TCP forwarding, whether the channel has been
 					 fully initialised */
@@ -94,7 +93,7 @@
 	int sepfds; /* Whether this channel has seperate pipes for in/out or not */
 	char *name;
 	int (*inithandler)(struct Channel*);
-	int (*checkclose)(struct Channel*);
+	int (*check_close)(struct Channel*);
 	void (*reqhandler)(struct Channel*);
 	void (*closehandler)(struct Channel*);
 
--- a/cli-channel.c	Wed Oct 11 16:00:50 2006 +0000
+++ b/cli-channel.c	Thu Oct 12 03:01:10 2006 +0000
@@ -39,9 +39,6 @@
 	TRACE(("enter recv_msg_channel_extended_data"))
 
 	channel = getchannel();
-	if (channel == NULL) {
-		dropbear_exit("Unknown channel");
-	}
 
 	if (channel->type != &clichansess) {
 		TRACE(("leave recv_msg_channel_extended_data: chantype is wrong"))
--- a/common-channel.c	Wed Oct 11 16:00:50 2006 +0000
+++ b/common-channel.c	Thu Oct 12 03:01:10 2006 +0000
@@ -43,18 +43,15 @@
 static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf);
 static void send_msg_channel_window_adjust(struct Channel *channel, 
 		unsigned int incr);
-static void send_msg_channel_data(struct Channel *channel, int isextended,
-		unsigned int exttype);
+static void send_msg_channel_data(struct Channel *channel, int isextended);
 static void send_msg_channel_eof(struct Channel *channel);
 static void send_msg_channel_close(struct Channel *channel);
-static void removechannel(struct Channel *channel);
-static void deletechannel(struct Channel *channel);
-static void checkinitdone(struct Channel *channel);
-static void checkclose(struct Channel *channel);
-
-static void closewritefd(struct Channel * channel);
-static void closereadfd(struct Channel * channel, int fd);
-static void closechanfd(struct Channel *channel, int fd, int how);
+static void remove_channel(struct Channel *channel);
+static void delete_channel(struct Channel *channel);
+static void check_in_progress(struct Channel *channel);
+static unsigned int write_pending(struct Channel * channel);
+static void check_close(struct Channel *channel);
+static void close_chan_fd(struct Channel *channel, int fd, int how);
 
 #define FD_UNINIT (-2)
 #define FD_CLOSED (-1)
@@ -85,7 +82,7 @@
 	for (i = 0; i < ses.chansize; i++) {
 		if (ses.channels[i] != NULL) {
 			TRACE(("channel %d closing", i))
-			removechannel(ses.channels[i]);
+			remove_channel(ses.channels[i]);
 		}
 	}
 	m_free(ses.channels);
@@ -135,8 +132,8 @@
 	newchan = (struct Channel*)m_malloc(sizeof(struct Channel));
 	newchan->type = type;
 	newchan->index = i;
-	newchan->sentclosed = newchan->recvclosed = 0;
-	newchan->senteof = newchan->recveof = 0;
+	newchan->sent_close = newchan->recv_close = 0;
+	newchan->sent_eof = newchan->recv_eof = 0;
 
 	newchan->remotechan = remotechan;
 	newchan->transwindow = transwindow;
@@ -164,26 +161,35 @@
 }
 
 /* Returns the channel structure corresponding to the channel in the current
- * data packet (ses.payload must be positioned appropriately) */
-struct Channel* getchannel() {
+ * data packet (ses.payload must be positioned appropriately).
+ * A valid channel is always returns, it will fail fatally with an unknown
+ * channel */
+static struct Channel* getchannel_msg(const char* kind) {
 
 	unsigned int chan;
 
 	chan = buf_getint(ses.payload);
 	if (chan >= ses.chansize || ses.channels[chan] == NULL) {
-		return NULL;
+		if (kind) {
+			dropbear_exit("%s for unknown channel %d", kind, chan);
+		} else {
+			dropbear_exit("Unknown channel %d", chan);
+		}
 	}
 	return ses.channels[chan];
 }
 
+struct Channel* getchannel() {
+	return getchannel_msg(NULL);
+}
+
 /* Iterate through the channels, performing IO if available */
 void channelio(fd_set *readfds, fd_set *writefds) {
 
 	struct Channel *channel;
 	unsigned int i;
-	int ret;
 
-	/* iterate through all the possible channels */
+	/* foreach channel */
 	for (i = 0; i < ses.chansize; i++) {
 
 		channel = ses.channels[i];
@@ -194,40 +200,22 @@
 
 		/* read data and send it over the wire */
 		if (channel->readfd >= 0 && FD_ISSET(channel->readfd, readfds)) {
-			send_msg_channel_data(channel, 0, 0);
+			send_msg_channel_data(channel, 0);
 		}
 
 		/* read stderr data and send it over the wire */
 		if (channel->extrabuf == NULL &&
 				channel->errfd >= 0 && FD_ISSET(channel->errfd, readfds)) {
-				send_msg_channel_data(channel, 1, SSH_EXTENDED_DATA_STDERR);
-		}
-
-		/* if we can read from the writefd, it might be closed, so we try to
-		 * see if it has errors */
-		if (IS_DROPBEAR_SERVER && channel->writefd >= 0 
-				&& channel->writefd != channel->readfd
-				&& FD_ISSET(channel->writefd, readfds)) {
-			if (channel->initconn) {
-				/* Handling for "in progress" connection - this is needed
-				 * to avoid spinning 100% CPU when we connect to a server
-				 * which doesn't send anything (tcpfwding) */
-				checkinitdone(channel);
-				continue; /* Important not to use the channel after 
-							 checkinitdone(), as it may be NULL */
-			}
-			ret = write(channel->writefd, NULL, 0); /* Fake write */
-			if (ret < 0 && errno != EINTR && errno != EAGAIN) {
-				closewritefd(channel);
-			}
+				send_msg_channel_data(channel, 1);
 		}
 
 		/* write to program/pipe stdin */
 		if (channel->writefd >= 0 && FD_ISSET(channel->writefd, writefds)) {
 			if (channel->initconn) {
-				checkinitdone(channel);
+				/* XXX should this go somewhere cleaner? */
+				check_in_progress(channel);
 				continue; /* Important not to use the channel after
-							 checkinitdone(), as it may be NULL */
+							 check_in_progress(), as it may be NULL */
 			}
 			writechannel(channel, channel->writefd, channel->writebuf);
 		}
@@ -238,10 +226,10 @@
 			writechannel(channel, channel->errfd, channel->extrabuf);
 		}
 	
-		/* now handle any of the channel-closing type stuff */
-		checkclose(channel);
+		/* handle any channel closing etc */
+		check_close(channel);
 
-	} /* foreach channel */
+	}
 
 	/* Listeners such as TCP, X11, agent-auth */
 #ifdef USING_LISTENERS
@@ -250,57 +238,65 @@
 }
 
 
-/* do all the EOF/close type stuff checking for a channel */
-static void checkclose(struct Channel *channel) {
+/* Returns true if there is data remaining to be written to stdin or
+ * stderr of a channel's endpoint. */
+static unsigned int write_pending(struct Channel * channel) {
 
-	TRACE(("checkclose: writefd %d, readfd %d, errfd %d, sentclosed %d, recvclosed %d",
+	if (channel->writefd >= 0 && cbuf_getused(channel->writebuf) > 0) {
+		return 1;
+	} else if (channel->errfd >= 0 && channel->extrabuf && 
+			cbuf_getused(channel->writebuf) > 0) {
+		return 1;
+	}
+	return 0;
+}
+
+
+/* EOF/close handling */
+static void check_close(struct Channel *channel) {
+
+	TRACE(("check_close: writefd %d, readfd %d, errfd %d, sent_close %d, recv_close %d",
 				channel->writefd, channel->readfd,
-				channel->errfd, channel->sentclosed, channel->recvclosed))
+				channel->errfd, channel->sent_close, channel->recv_close))
 	TRACE(("writebuf size %d extrabuf ptr 0x%x extrabuf size %d",
 				cbuf_getused(channel->writebuf),
 				channel->writebuf,
 				channel->writebuf ? 0 : cbuf_getused(channel->extrabuf)))
 
-	/* server chansession channels are special, since readfd mightn't
-	 * close in the case of "sleep 4 & echo blah" until the sleep is up */
-	if (channel->type->checkclose) {
-		if (channel->type->checkclose(channel)) {
-			closewritefd(channel);
-			closereadfd(channel, channel->readfd);
-			closereadfd(channel, channel->errfd);
-		}
+	/* A bit of a hack for closing up server session channels */
+	if (channel->writefd >= 0 
+			&& channel->type->check_close 
+			&& channel->type->check_close(channel)) {
+		TRACE(("channel->type->check_close got hit"))
+		close_chan_fd(channel, channel->writefd, SHUT_WR);
 	}
 
-	if (!channel->senteof
-		&& channel->readfd == FD_CLOSED 
-		&& (channel->extrabuf != NULL || channel->errfd == FD_CLOSED)) {
+	if (channel->recv_close && !write_pending(channel)) {
+		if (! channel->sent_close) {
+			TRACE(("Sending MSG_CHANNEL_CLOSE in response to same."))
+			send_msg_channel_close(channel);
+		}
+		remove_channel(channel);
+		return;
+	}
+
+	if (channel->recv_eof && !write_pending(channel)) {
+		close_chan_fd(channel, channel->writefd, SHUT_WR);
+	}
+
+	if (!channel->sent_eof
+			&& channel->readfd == FD_CLOSED 
+			&& (channel->extrabuf != NULL || channel->errfd == FD_CLOSED)) {
 		send_msg_channel_eof(channel);
 	}
 
-	if (!channel->sentclosed
-		&& channel->writefd == FD_CLOSED
-		&& channel->readfd == FD_CLOSED
-		&& (channel->extrabuf != NULL || channel->errfd == FD_CLOSED)) {
+	if (!channel->sent_close
+			&& channel->writefd == FD_CLOSED
+			&& channel->readfd == FD_CLOSED
+			&& (channel->extrabuf != NULL || channel->errfd == FD_CLOSED)) {
 		send_msg_channel_close(channel);
 	}
 
-	/* When either party wishes to terminate the channel, it sends
-	 * SSH_MSG_CHANNEL_CLOSE.  Upon receiving this message, a party MUST
-	 * send back a SSH_MSG_CHANNEL_CLOSE unless it has already sent this
-	 * message for the channel.  The channel is considered closed for a
-	 * party when it has both sent and received SSH_MSG_CHANNEL_CLOSE, and
-	 * the party may then reuse the channel number.  A party MAY send
-	 * SSH_MSG_CHANNEL_CLOSE without having sent or received
-	 * SSH_MSG_CHANNEL_EOF. 
-	 * (from draft-ietf-secsh-connect)
-	 */
-	if (channel->recvclosed) {
-		if (! channel->sentclosed) {
-			TRACE(("Sending MSG_CHANNEL_CLOSE in response to same."))
-			send_msg_channel_close(channel);
-		}
-		removechannel(channel);
-	}
 }
 
 
@@ -308,36 +304,34 @@
  * if so, set up the channel properly. Otherwise, the channel is cleaned up, so
  * it is important that the channel reference isn't used after a call to this
  * function */
-static void checkinitdone(struct Channel *channel) {
+static void check_in_progress(struct Channel *channel) {
 
 	int val;
 	socklen_t vallen = sizeof(val);
 
-	TRACE(("enter checkinitdone"))
+	TRACE(("enter check_in_progress"))
 
 	if (getsockopt(channel->writefd, SOL_SOCKET, SO_ERROR, &val, &vallen)
 			|| val != 0) {
 		send_msg_channel_open_failure(channel->remotechan,
 				SSH_OPEN_CONNECT_FAILED, "", "");
 		close(channel->writefd);
-		deletechannel(channel);
-		TRACE(("leave checkinitdone: fail"))
+		delete_channel(channel);
+		TRACE(("leave check_in_progress: fail"))
 	} else {
 		send_msg_channel_open_confirmation(channel, channel->recvwindow,
 				channel->recvmaxpacket);
 		channel->readfd = channel->writefd;
 		channel->initconn = 0;
-		TRACE(("leave checkinitdone: success"))
+		TRACE(("leave check_in_progress: success"))
 	}
 }
 
 
-
 /* Send the close message and set the channel as closed */
 static void send_msg_channel_close(struct Channel *channel) {
 
 	TRACE(("enter send_msg_channel_close"))
-	/* XXX server */
 	if (channel->type->closehandler) {
 		channel->type->closehandler(channel);
 	}
@@ -349,8 +343,8 @@
 
 	encrypt_packet();
 
-	channel->senteof = 1;
-	channel->sentclosed = 1;
+	channel->sent_eof = 1;
+	channel->sent_close = 1;
 	TRACE(("leave send_msg_channel_close"))
 }
 
@@ -365,7 +359,7 @@
 
 	encrypt_packet();
 
-	channel->senteof = 1;
+	channel->sent_eof = 1;
 
 	TRACE(("leave send_msg_channel_eof"))
 }
@@ -385,9 +379,7 @@
 	len = write(fd, cbuf_readptr(cbuf, maxlen), maxlen);
 	if (len <= 0) {
 		if (len < 0 && errno != EINTR) {
-			/* no more to write - we close it even if the fd was stderr, since
-			 * that's a nasty failure too */
-			closewritefd(channel);
+			close_chan_fd(channel, fd, SHUT_WR);
 		}
 		TRACE(("leave writechannel: len <= 0"))
 		return;
@@ -396,13 +388,6 @@
 	cbuf_incrread(cbuf, len);
 	channel->recvdonelen += len;
 
-	if (fd == channel->writefd && cbuf_getused(cbuf) == 0 && channel->recveof) { 
-		/* Check if we're closing up */
-		closewritefd(channel);
-		TRACE(("leave writechannel: recveof set"))
-		return;
-	}
-
 	/* Window adjust handling */
 	if (channel->recvdonelen >= RECV_WINDOWEXTEND) {
 		/* Set it back to max window */
@@ -416,7 +401,6 @@
 	dropbear_assert(channel->extrabuf == NULL ||
 			channel->recvwindow <= cbuf_getavail(channel->extrabuf));
 	
-	
 	TRACE(("leave writechannel"))
 }
 
@@ -446,19 +430,6 @@
 			}
 		}
 
-		TRACE(("writefd = %d, readfd %d, errfd %d, bufused %d", 
-					channel->writefd, channel->readfd,
-					channel->errfd,
-					cbuf_getused(channel->writebuf) ))
-
-		/* For checking FD status (ie closure etc) - we don't actually
-		 * read data from writefd. We don't want to do this for the client,
-		 * since redirection to /dev/null will make it spin in the select */
-		if (IS_DROPBEAR_SERVER && channel->writefd >= 0 
-				&& channel->writefd != channel->readfd) {
-			FD_SET(channel->writefd, readfds);
-		}
-
 		/* Stuff from the wire */
 		if ((channel->writefd >= 0 && cbuf_getused(channel->writebuf) > 0 )
 				|| channel->initconn) {
@@ -487,18 +458,11 @@
 
 	TRACE(("enter recv_msg_channel_eof"))
 
-	channel = getchannel();
-	if (channel == NULL) {
-		dropbear_exit("EOF for unknown channel");
-	}
+	channel = getchannel_msg("EOF");
 
-	channel->recveof = 1;
-	if (cbuf_getused(channel->writebuf) == 0
-			&& (channel->extrabuf == NULL 
-					|| cbuf_getused(channel->extrabuf) == 0)) {
-		closewritefd(channel);
-	}
+	channel->recv_eof = 1;
 
+	check_close(channel);
 	TRACE(("leave recv_msg_channel_eof"))
 }
 
@@ -510,27 +474,20 @@
 
 	TRACE(("enter recv_msg_channel_close"))
 
-	channel = getchannel();
-	if (channel == NULL) {
-		/* disconnect ? */
-		dropbear_exit("Close for unknown channel");
-	}
+	channel = getchannel_msg("Close");
 
-	channel->recveof = 1;
-	channel->recvclosed = 1;
+	channel->recv_eof = 1;
+	channel->recv_close = 1;
 
-	if (channel->sentclosed) {
-		removechannel(channel);
-	}
-
+	check_close(channel);
 	TRACE(("leave recv_msg_channel_close"))
 }
 
 /* Remove a channel entry, this is only executed after both sides have sent
  * channel close */
-static void removechannel(struct Channel * channel) {
+static void remove_channel(struct Channel * channel) {
 
-	TRACE(("enter removechannel"))
+	TRACE(("enter remove_channel"))
 	TRACE(("channel index is %d", channel->index))
 
 	cbuf_free(channel->writebuf);
@@ -543,20 +500,20 @@
 
 
 	/* close the FDs in case they haven't been done
-	 * yet (ie they were shutdown etc */
+	 * yet (they might have been shutdown etc) */
 	close(channel->writefd);
 	close(channel->readfd);
 	close(channel->errfd);
 
 	channel->typedata = NULL;
 
-	deletechannel(channel);
+	delete_channel(channel);
 
-	TRACE(("leave removechannel"))
+	TRACE(("leave remove_channel"))
 }
 
 /* Remove a channel entry */
-static void deletechannel(struct Channel *channel) {
+static void delete_channel(struct Channel *channel) {
 
 	ses.channels[channel->index] = NULL;
 	m_free(channel);
@@ -574,10 +531,6 @@
 	TRACE(("enter recv_msg_channel_request"))
 	
 	channel = getchannel();
-	if (channel == NULL) {
-		/* disconnect ? */
-		dropbear_exit("Unknown channel");
-	}
 
 	if (channel->type->reqhandler) {
 		channel->type->reqhandler(channel);
@@ -594,20 +547,15 @@
  * chan is the remote channel, isextended is 0 if it is normal data, 1
  * if it is extended data. if it is extended, then the type is in
  * exttype */
-static void send_msg_channel_data(struct Channel *channel, int isextended,
-		unsigned int exttype) {
+static void send_msg_channel_data(struct Channel *channel, int isextended) {
 
-	buffer *buf;
 	int len;
-	unsigned int maxlen;
+	size_t maxlen, size_pos;
 	int fd;
 
-/*	TRACE(("enter send_msg_channel_data"))
-	TRACE(("extended = %d type = %d", isextended, exttype))*/
-
 	CHECKCLEARTOWRITE();
 
-	dropbear_assert(!channel->sentclosed);
+	dropbear_assert(!channel->sent_close);
 
 	if (isextended) {
 		fd = channel->errfd;
@@ -621,40 +569,37 @@
 	 * exttype if is extended */
 	maxlen = MIN(maxlen, 
 			ses.writepayload->size - 1 - 4 - 4 - (isextended ? 4 : 0));
+	TRACE(("maxlen %d", maxlen))
 	if (maxlen == 0) {
 		TRACE(("leave send_msg_channel_data: no window"))
-		return; /* the data will get written later */
+		return;
 	}
 
+	buf_putbyte(ses.writepayload, 
+			isextended ? SSH_MSG_CHANNEL_EXTENDED_DATA : SSH_MSG_CHANNEL_DATA);
+	buf_putint(ses.writepayload, channel->remotechan);
+	if (isextended) {
+		buf_putint(ses.writepayload, SSH_EXTENDED_DATA_STDERR);
+	}
+	/* a dummy size first ...*/
+	size_pos = ses.writepayload->pos;
+	buf_putint(ses.writepayload, 0);
+
 	/* read the data */
-	TRACE(("maxlen %d", maxlen))
-	buf = buf_new(maxlen);
-	TRACE(("buf pos %d data %x", buf->pos, buf->data))
-	len = read(fd, buf_getwriteptr(buf, maxlen), maxlen);
+	len = read(fd, buf_getwriteptr(ses.writepayload, maxlen), maxlen);
 	if (len <= 0) {
-		/* on error/eof, send eof */
 		if (len == 0 || errno != EINTR) {
-			closereadfd(channel, fd);
+			close_chan_fd(channel, fd, SHUT_RD);
 		}
-		buf_free(buf);
-		buf = NULL;
+		ses.writepayload->len = ses.writepayload->pos = 0;
 		TRACE(("leave send_msg_channel_data: read err or EOF for fd %d", 
 					channel->index));
 		return;
 	}
-	buf_incrlen(buf, len);
-
-	buf_putbyte(ses.writepayload, 
-			isextended ? SSH_MSG_CHANNEL_EXTENDED_DATA : SSH_MSG_CHANNEL_DATA);
-	buf_putint(ses.writepayload, channel->remotechan);
-
-	if (isextended) {
-		buf_putint(ses.writepayload, exttype);
-	}
-
-	buf_putstring(ses.writepayload, buf_getptr(buf, len), len);
-	buf_free(buf);
-	buf = NULL;
+	buf_incrwritepos(ses.writepayload, len);
+	/* ... real size here */
+	buf_setpos(ses.writepayload, size_pos);
+	buf_putint(ses.writepayload, len);
 
 	channel->transwindow -= len;
 
@@ -668,9 +613,6 @@
 	struct Channel *channel;
 
 	channel = getchannel();
-	if (channel == NULL) {
-		dropbear_exit("Unknown channel");
-	}
 
 	common_recv_msg_channel_data(channel, channel->writefd, channel->writebuf);
 }
@@ -687,16 +629,19 @@
 
 	TRACE(("enter recv_msg_channel_data"))
 
-	if (channel->recveof) {
+	if (channel->recv_eof) {
 		dropbear_exit("received data after eof");
 	}
 
  	if (fd < 0) {
-		dropbear_exit("received data with bad writefd");
+		/* If we have encountered failed write, the far side might still
+		 * be sending data without having yet received our close notification.
+		 * We just drop the data. */
+		return;
 	}
 
 	datalen = buf_getint(ses.payload);
-
+	TRACE(("length %d", datalen))
 
 	maxdata = cbuf_getavail(cbuf);
 
@@ -738,9 +683,6 @@
 	unsigned int incr;
 	
 	channel = getchannel();
-	if (channel == NULL) {
-		dropbear_exit("Unknown channel");
-	}
 	
 	incr = buf_getint(ses.payload);
 	TRACE(("received window increment %d", incr))
@@ -767,7 +709,6 @@
 }
 	
 /* Handle a new channel request, performing any channel-type-specific setup */
-/* XXX server */
 void recv_msg_channel_open() {
 
 	unsigned char *type;
@@ -799,6 +740,7 @@
 	/* Get the channel type. Client and server style invokation will set up a
 	 * different list for ses.chantypes at startup. We just iterate through
 	 * this list and find the matching name */
+	/* XXX fugly */
 	for (cp = &ses.chantypes[0], chantype = (*cp); 
 			chantype != NULL;
 			cp++, chantype = (*cp)) {
@@ -824,13 +766,13 @@
 
 	if (channel->type->inithandler) {
 		ret = channel->type->inithandler(channel);
+		if (ret == SSH_OPEN_IN_PROGRESS) {
+			/* We'll send the confirmation later */
+			goto cleanup;
+		}
 		if (ret > 0) {
-			if (ret == SSH_OPEN_IN_PROGRESS) {
-				/* We'll send the confirmation later */
-				goto cleanup;
-			}
 			errtype = ret;
-			deletechannel(channel);
+			delete_channel(channel);
 			TRACE(("inithandler returned failure %d", ret))
 			goto failure;
 		}
@@ -914,6 +856,47 @@
 	TRACE(("leave send_msg_channel_open_confirmation"))
 }
 
+/* close a fd, how is SHUT_RD or SHUT_WR */
+static void close_chan_fd(struct Channel *channel, int fd, int how) {
+
+	int closein = 0, closeout = 0;
+
+	if (channel->type->sepfds) {
+		TRACE(("shutdown((%d), %d)", fd, how))
+		shutdown(fd, how);
+		if (how == 0) {
+			closeout = 1;
+		} else {
+			closein = 1;
+		}
+	} else {
+		close(fd);
+		closein = closeout = 1;
+	}
+
+	if (closeout && fd == channel->readfd) {
+		channel->readfd = FD_CLOSED;
+	}
+	if (closeout && (channel->extrabuf == NULL) && (fd == channel->errfd)) {
+		channel->errfd = FD_CLOSED;
+	}
+
+	if (closein && fd == channel->writefd) {
+		channel->writefd = FD_CLOSED;
+	}
+	if (closein && (channel->extrabuf != NULL) && (fd == channel->errfd)) {
+		channel->errfd = FD_CLOSED;
+	}
+
+	/* if we called shutdown on it and all references are gone, then we 
+	 * need to close() it to stop it lingering */
+	if (channel->type->sepfds && channel->readfd == FD_CLOSED 
+		&& channel->writefd == FD_CLOSED && channel->errfd == FD_CLOSED) {
+		close(fd);
+	}
+}
+
+
 #if defined(USING_LISTENERS) || defined(DROPBEAR_CLIENT)
 /* Create a new channel, and start the open request. This is intended
  * for X11, agent, tcp forwarding, and should be filled with channel-specific
@@ -962,9 +945,6 @@
 	TRACE(("enter recv_msg_channel_open_confirmation"))
 
 	channel = getchannel();
-	if (channel == NULL) {
-		dropbear_exit("Unknown channel");
-	}
 
 	if (!channel->await_open) {
 		dropbear_exit("unexpected channel reply");
@@ -982,7 +962,7 @@
 	if (channel->type->inithandler) {
 		ret = channel->type->inithandler(channel);
 		if (ret > 0) {
-			removechannel(channel);
+			remove_channel(channel);
 			TRACE(("inithandler returned failure %d", ret))
 		}
 	}
@@ -997,74 +977,12 @@
 	struct Channel * channel;
 
 	channel = getchannel();
-	if (channel == NULL) {
-		dropbear_exit("Unknown channel");
-	}
 
 	if (!channel->await_open) {
 		dropbear_exit("unexpected channel reply");
 	}
 	channel->await_open = 0;
 
-	removechannel(channel);
+	remove_channel(channel);
 }
 #endif /* USING_LISTENERS */
-
-/* close a stdout/stderr fd */
-static void closereadfd(struct Channel * channel, int fd) {
-
-	/* don't close it if it is the same as writefd,
-	 * unless writefd is already set -1 */
-	TRACE(("enter closereadfd"))
-	closechanfd(channel, fd, 0);
-	TRACE(("leave closereadfd"))
-}
-
-/* close a stdin fd */
-static void closewritefd(struct Channel * channel) {
-
-	TRACE(("enter closewritefd"))
-	closechanfd(channel, channel->writefd, 1);
-	TRACE(("leave closewritefd"))
-}
-
-/* close a fd, how is 0 for stdout/stderr, 1 for stdin */
-static void closechanfd(struct Channel *channel, int fd, int how) {
-
-	int closein = 0, closeout = 0;
-
-	/* XXX server */
-	if (channel->type->sepfds) {
-		TRACE(("shutdown((%d), %d)", fd, how))
-		shutdown(fd, how);
-		if (how == 0) {
-			closeout = 1;
-		} else {
-			closein = 1;
-		}
-	} else {
-		close(fd);
-		closein = closeout = 1;
-	}
-
-	if (closeout && fd == channel->readfd) {
-		channel->readfd = FD_CLOSED;
-	}
-	if (closeout && (channel->extrabuf == NULL) && (fd == channel->errfd)) {
-		channel->errfd = FD_CLOSED;
-	}
-
-	if (closein && fd == channel->writefd) {
-		channel->writefd = FD_CLOSED;
-	}
-	if (closein && (channel->extrabuf != NULL) && (fd == channel->errfd)) {
-		channel->errfd = FD_CLOSED;
-	}
-
-	/* if we called shutdown on it and all references are gone, then we 
-	 * need to close() it to stop it lingering */
-	if (channel->type->sepfds && channel->readfd == FD_CLOSED 
-		&& channel->writefd == FD_CLOSED && channel->errfd == FD_CLOSED) {
-		close(fd);
-	}
-}
--- a/debug.h	Wed Oct 11 16:00:50 2006 +0000
+++ b/debug.h	Thu Oct 12 03:01:10 2006 +0000
@@ -39,7 +39,7 @@
  * Caution: Don't use this in an unfriendly environment (ie unfirewalled),
  * since the printing may not sanitise strings etc. This will add a reasonable
  * amount to your executable size. */
-/*#define DEBUG_TRACE */
+#define DEBUG_TRACE
 
 /* All functions writing to the cleartext payload buffer call
  * CHECKCLEARTOWRITE() before writing. This is only really useful if you're
--- a/svr-chansession.c	Wed Oct 11 16:00:50 2006 +0000
+++ b/svr-chansession.c	Thu Oct 12 03:01:10 2006 +0000
@@ -59,7 +59,6 @@
 		struct ChanSess * chansess);
 static void send_msg_chansess_exitsignal(struct Channel * channel,
 		struct ChanSess * chansess);
-static int sesscheckclose(struct Channel *channel);
 static void get_termmodes(struct ChanSess *chansess);
 
 
@@ -67,7 +66,8 @@
 extern char** environ;
 
 static int sesscheckclose(struct Channel *channel) {
-	return channel->writefd == -1;
+	struct ChanSess *chansess = (struct ChanSess*)channel->typedata;
+	return chansess->exit.exitpid != -1;
 }
 
 /* Handler for childs exiting, store the state for return to the client */