- djm@cvs.openbsd.org 2011/05/08 12:52:01

     [PROTOCOL.mux clientloop.c clientloop.h mux.c]
     improve our behaviour when TTY allocation fails: if we are in
     RequestTTY=auto mode (the default), then do not treat at TTY
     allocation error as fatal but rather just restore the local TTY
     to cooked mode and continue. This is more graceful on devices that
     never allocate TTYs.

     If RequestTTY is set to "yes" or "force", then failure to allocate
     a TTY is fatal.

     ok markus@

1 files changed, 48 insertions, 12 deletions

diff --git a/mux.c b/mux.c
index 1afd1bdf3..101d7524b 100644
--- a/mux.c
+++ b/mux.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mux.c,v 1.27 2011/05/06 21:34:32 djm Exp $ */
+/* $OpenBSD: mux.c,v 1.28 2011/05/08 12:52:01 djm Exp $ */
 /*
  * Copyright (c) 2002-2008 Damien Miller <djm@openbsd.org>
  *
@@ -153,6 +153,7 @@ struct mux_master_state {
 #define MUX_S_ALIVE             0x80000005
 #define MUX_S_SESSION_OPENED    0x80000006
 #define MUX_S_REMOTE_PORT       0x80000007
+#define MUX_S_TTY_ALLOC_FAIL    0x80000008
 
 /* type codes for MUX_C_OPEN_FWD and MUX_C_CLOSE_FWD */
 #define MUX_FWD_LOCAL   1
@@ -1054,6 +1055,27 @@ mux_exit_message(Channel *c, int exitval)
         buffer_free(&m);
 }
 
+void
+mux_tty_alloc_failed(Channel *c)
+{
+        Buffer m;
+        Channel *mux_chan;
+
+        debug3("%s: channel %d: TTY alloc failed", __func__, c->self);
+
+        if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL)
+                fatal("%s: channel %d missing mux channel %d",
+                    __func__, c->self, c->ctl_chan);
+
+        /* Append exit message packet to control socket output queue */
+        buffer_init(&m);
+        buffer_put_int(&m, MUX_S_TTY_ALLOC_FAIL);
+        buffer_put_int(&m, c->self);
+
+        buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m));
+        buffer_free(&m);
+}
+
 /* Prepare a mux master to listen on a Unix domain socket. */
 void
 muxserver_listen(void)
@@ -1612,7 +1634,7 @@ mux_client_request_session(int fd)
         char *e, *term;
         u_int i, rid, sid, esid, exitval, type, exitval_seen;
         extern char **environ;
-        int devnull;
+        int devnull, rawmode;
 
         debug3("%s: entering", __func__);
 
@@ -1708,6 +1730,7 @@ mux_client_request_session(int fd)
         signal(SIGTERM, control_client_sighandler);
         signal(SIGWINCH, control_client_sigrelay);
 
+        rawmode = tty_flag;
         if (tty_flag)
                 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
 
@@ -1723,22 +1746,35 @@ mux_client_request_session(int fd)
                 if (mux_client_read_packet(fd, &m) != 0)
                         break;
                 type = buffer_get_int(&m);
-                if (type != MUX_S_EXIT_MESSAGE) {
+                switch (type) {
+                case MUX_S_TTY_ALLOC_FAIL:
+                        if ((esid = buffer_get_int(&m)) != sid)
+                                fatal("%s: tty alloc fail on unknown session: "
+                                    "my id %u theirs %u",
+                                    __func__, sid, esid);
+                        leave_raw_mode(options.request_tty ==
+                            REQUEST_TTY_FORCE);
+                        rawmode = 0;
+                        continue;
+                case MUX_S_EXIT_MESSAGE:
+                        if ((esid = buffer_get_int(&m)) != sid)
+                                fatal("%s: exit on unknown session: "
+                                    "my id %u theirs %u",
+                                    __func__, sid, esid);
+                        if (exitval_seen)
+                                fatal("%s: exitval sent twice", __func__);
+                        exitval = buffer_get_int(&m);
+                        exitval_seen = 1;
+                        continue;
+                default:
                         e = buffer_get_string(&m, NULL);
                         fatal("%s: master returned error: %s", __func__, e);
                 }
-                if ((esid = buffer_get_int(&m)) != sid)
-                        fatal("%s: exit on unknown session: my id %u theirs %u",
-                            __func__, sid, esid);
-                debug("%s: master session id: %u", __func__, sid);
-                if (exitval_seen)
-                        fatal("%s: exitval sent twice", __func__);
-                exitval = buffer_get_int(&m);
-                exitval_seen = 1;
         }
 
         close(fd);
-        leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+        if (rawmode)
+                leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
 
         if (muxclient_terminate) {
                 debug2("Exiting on signal %d", muxclient_terminate);