X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/42f11eb24fa39e437b4f1e6beb5cc83901aa5bdd..27c47c0ad07c3e63270ef33b5f3f7226d4d58582:/nchan.c

diff --git a/nchan.c b/nchan.c
index d049a945..2680f0a6 100644
--- a/nchan.c
+++ b/nchan.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999 Markus Friedl.  All rights reserved.
+ * Copyright (c) 1999, 2000, 2001 Markus Friedl.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -23,17 +23,42 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: nchan.c,v 1.22 2001/01/21 19:05:52 markus Exp $");
+RCSID("$OpenBSD: nchan.c,v 1.32 2001/10/10 22:18:47 markus Exp $");
 
 #include "ssh1.h"
 #include "ssh2.h"
 #include "buffer.h"
 #include "packet.h"
 #include "channels.h"
-#include "nchan.h"
 #include "compat.h"
 #include "log.h"
 
+/*
+ * SSH Protocol 1.5 aka New Channel Protocol
+ * Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored.
+ * Written by Markus Friedl in October 1999
+ *
+ * Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the
+ * tear down of channels:
+ *
+ * 1.3:	strict request-ack-protocol:
+ * 	CLOSE	->
+ * 		<-  CLOSE_CONFIRM
+ *
+ * 1.5:	uses variations of:
+ * 	IEOF	->
+ * 		<-  OCLOSE
+ * 		<-  IEOF
+ * 	OCLOSE	->
+ * 	i.e. both sides have to close the channel
+ *
+ * 2.0: the EOF messages are optional
+ *
+ * See the debugging output from 'ssh -v' and 'sshd -d' of
+ * ssh-1.2.27 as an example.
+ *
+ */
+
 /* functions manipulating channel states */
 /*
  * EVENTS update channel input/output states execute ACTIONS
@@ -49,17 +74,14 @@ chan_event_fn *chan_obuf_empty			= NULL;
 /*
  * ACTIONS: should never update the channel states
  */
-static void	chan_send_ieof1(Channel *c);
-static void	chan_send_oclose1(Channel *c);
-static void	chan_send_close2(Channel *c);
-static void	chan_send_eof2(Channel *c);
-
-/* channel cleanup */
-chan_event_fn *chan_delete_if_full_closed	= NULL;
+static void	chan_send_ieof1(Channel *);
+static void	chan_send_oclose1(Channel *);
+static void	chan_send_close2(Channel *);
+static void	chan_send_eof2(Channel *);
 
 /* helper */
-static void	chan_shutdown_write(Channel *c);
-static void	chan_shutdown_read(Channel *c);
+static void	chan_shutdown_write(Channel *);
+static void	chan_shutdown_read(Channel *);
 
 /*
  * SSH1 specific implementation of event functions
@@ -87,7 +109,7 @@ chan_rcvd_oclose1(Channel *c)
 		c->istate = CHAN_INPUT_CLOSED;
 		break;
 	default:
-		error("channel %d: protocol error: chan_rcvd_oclose for istate %d",
+		error("channel %d: protocol error: rcvd_oclose for istate %d",
 		    c->self, c->istate);
 		return;
 	}
@@ -101,13 +123,15 @@ chan_read_failed_12(Channel *c)
 		debug("channel %d: input open -> drain", c->self);
 		chan_shutdown_read(c);
 		c->istate = CHAN_INPUT_WAIT_DRAIN;
+#if 0
 		if (buffer_len(&c->input) == 0) {
 			debug("channel %d: input: no drain shortcut", c->self);
 			chan_ibuf_empty(c);
 		}
+#endif
 		break;
 	default:
-		error("channel %d: internal error: we do not read, but chan_read_failed for istate %d",
+		error("channel %d: chan_read_failed for istate %d",
 		    c->self, c->istate);
 		break;
 	}
@@ -117,7 +141,7 @@ chan_ibuf_empty1(Channel *c)
 {
 	debug("channel %d: ibuf empty", c->self);
 	if (buffer_len(&c->input)) {
-		error("channel %d: internal error: chan_ibuf_empty for non empty buffer",
+		error("channel %d: chan_ibuf_empty for non empty buffer",
 		    c->self);
 		return;
 	}
@@ -128,7 +152,7 @@ chan_ibuf_empty1(Channel *c)
 		c->istate = CHAN_INPUT_WAIT_OCLOSE;
 		break;
 	default:
-		error("channel %d: internal error: chan_ibuf_empty for istate %d",
+		error("channel %d: chan_ibuf_empty for istate %d",
 		    c->self, c->istate);
 		break;
 	}
@@ -140,19 +164,23 @@ chan_rcvd_ieof1(Channel *c)
 	if (c->type != SSH_CHANNEL_OPEN) {
 		debug("channel %d: non-open", c->self);
 		if (c->istate == CHAN_INPUT_OPEN) {
-			debug("channel %d: non-open: input open -> wait_oclose", c->self);
+			debug("channel %d: non-open: input open -> wait_oclose",
+			    c->self);
 			chan_shutdown_read(c);
 			chan_send_ieof1(c);
 			c->istate = CHAN_INPUT_WAIT_OCLOSE;
 		} else {
-			error("channel %d: istate %d != open", c->self, c->istate);
+			error("channel %d: non-open: istate %d != open",
+			    c->self, c->istate);
 		}
 		if (c->ostate == CHAN_OUTPUT_OPEN) {
-			debug("channel %d: non-open: output open -> closed", c->self);
+			debug("channel %d: non-open: output open -> closed",
+			    c->self);
 			chan_send_oclose1(c);
 			c->ostate = CHAN_OUTPUT_CLOSED;
 		} else {
-			error("channel %d: ostate %d != open", c->self, c->ostate);
+			error("channel %d: non-open: ostate %d != open",
+			    c->self, c->ostate);
 		}
 		return;
 	}
@@ -166,7 +194,7 @@ chan_rcvd_ieof1(Channel *c)
 		c->ostate = CHAN_OUTPUT_CLOSED;
 		break;
 	default:
-		error("channel %d: protocol error: chan_rcvd_ieof for ostate %d",
+		error("channel %d: protocol error: rcvd_ieof for ostate %d",
 		    c->self, c->ostate);
 		break;
 	}
@@ -187,7 +215,7 @@ chan_write_failed1(Channel *c)
 		c->ostate = CHAN_OUTPUT_CLOSED;
 		break;
 	default:
-		error("channel %d: internal error: chan_write_failed for ostate %d",
+		error("channel %d: chan_write_failed for ostate %d",
 		    c->self, c->ostate);
 		break;
 	}
@@ -197,7 +225,7 @@ chan_obuf_empty1(Channel *c)
 {
 	debug("channel %d: obuf empty", c->self);
 	if (buffer_len(&c->output)) {
-		error("channel %d: internal error: chan_obuf_empty for non empty buffer",
+		error("channel %d: chan_obuf_empty for non empty buffer",
 		    c->self);
 		return;
 	}
@@ -208,7 +236,7 @@ chan_obuf_empty1(Channel *c)
 		c->ostate = CHAN_OUTPUT_CLOSED;
 		break;
 	default:
-		error("channel %d: internal error: chan_obuf_empty for ostate %d",
+		error("channel %d: internal error: obuf_empty for ostate %d",
 		    c->self, c->ostate);
 		break;
 	}
@@ -225,7 +253,7 @@ chan_send_ieof1(Channel *c)
 		packet_send();
 		break;
 	default:
-		error("channel %d: internal error: cannot send ieof for istate %d",
+		error("channel %d: cannot send ieof for istate %d",
 		    c->self, c->istate);
 		break;
 	}
@@ -244,21 +272,11 @@ chan_send_oclose1(Channel *c)
 		packet_send();
 		break;
 	default:
-		error("channel %d: internal error: cannot send oclose for ostate %d",
+		error("channel %d: cannot send oclose for ostate %d",
 		     c->self, c->ostate);
 		break;
 	}
 }
-static void
-chan_delete_if_full_closed1(Channel *c)
-{
-	debug3("channel %d: chan_delete_if_full_closed1: istate %d ostate %d",
-	    c->self, c->istate, c->ostate);
-	if (c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED) {
-		debug("channel %d: full closed", c->self);
-		channel_free(c->self);
-	}
-}
 
 /*
  * the same for SSH2
@@ -278,7 +296,10 @@ chan_rcvd_oclose2(Channel *c)
 	}
 	switch (c->ostate) {
 	case CHAN_OUTPUT_OPEN:
-		/* wait until a data from the channel is consumed if a CLOSE is received */
+		/*
+		 * wait until a data from the channel is consumed if a CLOSE
+		 * is received
+		 */
 		debug("channel %d: output open -> drain", c->self);
 		c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
 		break;
@@ -300,7 +321,7 @@ chan_ibuf_empty2(Channel *c)
 {
 	debug("channel %d: ibuf empty", c->self);
 	if (buffer_len(&c->input)) {
-		error("channel %d: internal error: chan_ibuf_empty for non empty buffer",
+		error("channel %d: chan_ibuf_empty for non empty buffer",
 		     c->self);
 		return;
 	}
@@ -312,7 +333,7 @@ chan_ibuf_empty2(Channel *c)
 		c->istate = CHAN_INPUT_CLOSED;
 		break;
 	default:
-		error("channel %d: internal error: chan_ibuf_empty for istate %d",
+		error("channel %d: chan_ibuf_empty for istate %d",
 		     c->self, c->istate);
 		break;
 	}
@@ -342,7 +363,7 @@ chan_write_failed2(Channel *c)
 		c->ostate = CHAN_OUTPUT_CLOSED;
 		break;
 	default:
-		error("channel %d: internal error: chan_write_failed for ostate %d",
+		error("channel %d: chan_write_failed for ostate %d",
 		    c->self, c->ostate);
 		break;
 	}
@@ -352,7 +373,7 @@ chan_obuf_empty2(Channel *c)
 {
 	debug("channel %d: obuf empty", c->self);
 	if (buffer_len(&c->output)) {
-		error("internal error: chan_obuf_empty %d for non empty buffer",
+		error("channel %d: chan_obuf_empty for non empty buffer",
 		    c->self);
 		return;
 	}
@@ -363,7 +384,7 @@ chan_obuf_empty2(Channel *c)
 		c->ostate = CHAN_OUTPUT_CLOSED;
 		break;
 	default:
-		error("channel %d: internal error: chan_obuf_empty for ostate %d",
+		error("channel %d: chan_obuf_empty for ostate %d",
 		    c->self, c->ostate);
 		break;
 	}
@@ -379,7 +400,7 @@ chan_send_eof2(Channel *c)
 		packet_send();
 		break;
 	default:
-		error("channel %d: internal error: cannot send eof for istate %d",
+		error("channel %d: cannot send eof for istate %d",
 		    c->self, c->istate);
 		break;
 	}
@@ -390,10 +411,10 @@ chan_send_close2(Channel *c)
 	debug("channel %d: send close", c->self);
 	if (c->ostate != CHAN_OUTPUT_CLOSED ||
 	    c->istate != CHAN_INPUT_CLOSED) {
-		error("channel %d: internal error: cannot send close for istate/ostate %d/%d",
+		error("channel %d: cannot send close for istate/ostate %d/%d",
 		    c->self, c->istate, c->ostate);
 	} else if (c->flags & CHAN_CLOSE_SENT) {
-		error("channel %d: internal error: already sent close", c->self);
+		error("channel %d: already sent close", c->self);
 	} else {
 		packet_start(SSH2_MSG_CHANNEL_CLOSE);
 		packet_put_int(c->remote_id);
@@ -401,24 +422,65 @@ chan_send_close2(Channel *c)
 		c->flags |= CHAN_CLOSE_SENT;
 	}
 }
-static void
-chan_delete_if_full_closed2(Channel *c)
+
+/* shared */
+
+void
+chan_mark_dead(Channel *c)
+{
+	c->type = SSH_CHANNEL_ZOMBIE;
+}
+
+int
+chan_is_dead(Channel *c, int send)
 {
-	debug3("channel %d: chan_delete_if_full_closed2: istate %d ostate %d",
-	    c->self, c->istate, c->ostate);
-	if (c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED) {
+	if (c->type == SSH_CHANNEL_ZOMBIE) {
+		debug("channel %d: zombie", c->self);
+		return 1;
+	}
+	if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
+		return 0;
+	if (!compat20) {
+		debug("channel %d: is dead", c->self);
+		return 1;
+	}
+	/*
+	 * we have to delay the close message if the efd (for stderr) is
+	 * still active
+	 */
+	if (((c->extended_usage != CHAN_EXTENDED_IGNORE) &&
+	    buffer_len(&c->extended) > 0)
+#if 0
+	    || ((c->extended_usage == CHAN_EXTENDED_READ) &&
+	    c->efd != -1)
+#endif
+	    ) {
+		debug2("channel %d: active efd: %d len %d type %s",
+		    c->self, c->efd, buffer_len(&c->extended),
+		    c->extended_usage==CHAN_EXTENDED_READ ?
+		       "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)) {
-			debug("channel %d: full closed2", c->self);
-			channel_free(c->self);
+			debug("channel %d: is dead", c->self);
+			return 1;
 		}
 	}
+	return 0;
 }
 
-/* shared */
 void
 chan_init_iostates(Channel *c)
 {
@@ -439,8 +501,6 @@ chan_init(void)
 		chan_rcvd_ieof			= chan_rcvd_ieof2;
 		chan_write_failed		= chan_write_failed2;
 		chan_obuf_empty			= chan_obuf_empty2;
-
-		chan_delete_if_full_closed	= chan_delete_if_full_closed2;
 	} else {
 		chan_rcvd_oclose		= chan_rcvd_oclose1;
 		chan_read_failed		= chan_read_failed_12;
@@ -449,8 +509,6 @@ chan_init(void)
 		chan_rcvd_ieof			= chan_rcvd_ieof1;
 		chan_write_failed		= chan_write_failed1;
 		chan_obuf_empty			= chan_obuf_empty1;
-
-		chan_delete_if_full_closed	= chan_delete_if_full_closed1;
 	}
 }
 
@@ -465,13 +523,14 @@ chan_shutdown_write(Channel *c)
 	debug("channel %d: close_write", c->self);
 	if (c->sock != -1) {
 		if (shutdown(c->sock, SHUT_WR) < 0)
-			debug("channel %d: chan_shutdown_write: shutdown() failed for fd%d: %.100s",
+			debug("channel %d: chan_shutdown_write: "
+			    "shutdown() failed for fd%d: %.100s",
 			    c->self, c->sock, strerror(errno));
 	} else {
-		if (close(c->wfd) < 0)
-			log("channel %d: chan_shutdown_write: close() failed for fd%d: %.100s",
+		if (channel_close_fd(&c->wfd) < 0)
+			log("channel %d: chan_shutdown_write: "
+			    "close() failed for fd%d: %.100s",
 			    c->self, c->wfd, strerror(errno));
-		c->wfd = -1;
 	}
 }
 static void
@@ -481,20 +540,21 @@ chan_shutdown_read(Channel *c)
 		return;
 	debug("channel %d: close_read", c->self);
 	if (c->sock != -1) {
-		/* 
+		/*
 		 * shutdown(sock, SHUT_READ) may return ENOTCONN if the
 		 * write side has been closed already. (bug on Linux)
+		 * HP-UX may return ENOTCONN also.
 		 */
 		if (shutdown(c->sock, SHUT_RD) < 0
-		    && (errno != ENOTCONN
-			|| c->ostate == CHAN_OUTPUT_OPEN
-			|| c->ostate == CHAN_OUTPUT_WAIT_DRAIN))
-			error("channel %d: chan_shutdown_read: shutdown() failed for fd%d [i%d o%d]: %.100s",
-			    c->self, c->sock, c->istate, c->ostate, strerror(errno));
+		    && errno != ENOTCONN)
+			error("channel %d: chan_shutdown_read: "
+			    "shutdown() failed for fd%d [i%d o%d]: %.100s",
+			    c->self, c->sock, c->istate, c->ostate,
+			    strerror(errno));
 	} else {
-		if (close(c->rfd) < 0)
-			log("channel %d: chan_shutdown_read: close() failed for fd%d: %.100s",
+		if (channel_close_fd(&c->rfd) < 0)
+			log("channel %d: chan_shutdown_read: "
+			    "close() failed for fd%d: %.100s",
 			    c->self, c->rfd, strerror(errno));
-		c->rfd = -1;
 	}
 }