- (djm) [channels.c serverloop.c] Fix so-called "hang on exit" (bz #52)

   when closing a tty session when a background process still holds tty
   fds open. Great detective work and patch by Marc Aurele La France,
   slightly tweaked by me; ok dtucker@

3 files changed, 29 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index 7dd2e4ab8..481bcfddf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+20070128
+ - (djm) [channels.c serverloop.c] Fix so-called "hang on exit" (bz #52)
+   when closing a tty session when a background process still holds tty
+   fds open. Great detective work and patch by Marc Aurele La France,
+   slightly tweaked by me; ok dtucker@
+
 20070123
  - (dtucker) [openbsd-compat/bsd-snprintf.c] Static declarations for public
    library interfaces aren't very helpful. Fix up the DOPR_OUTCH macro
@@ -2686,4 +2692,4 @@
    OpenServer 6 and add osr5bigcrypt support so when someone migrates
    passwords between UnixWare and OpenServer they will still work. OK dtucker@
 
-$Id: ChangeLog,v 1.4608 2007/01/23 13:07:29 dtucker Exp $
+$Id: ChangeLog,v 1.4609 2007/01/28 23:16:28 djm Exp $
diff --git a/channels.c b/channels.c
index 9d522a6c3..c68ad6419 100644
--- a/channels.c
+++ b/channels.c
@@ -1449,10 +1449,11 @@ channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
         int len;
 
         if (c->rfd != -1 &&
-            FD_ISSET(c->rfd, readset)) {
+            (c->detach_close || FD_ISSET(c->rfd, readset))) {
                 errno = 0;
                 len = read(c->rfd, buf, sizeof(buf));
-                if (len < 0 && (errno == EINTR || errno == EAGAIN))
+                if (len < 0 && (errno == EINTR ||
+                    (errno == EAGAIN && !(c->isatty && c->detach_close))))
                         return 1;
 #ifndef PTY_ZEROREAD
                 if (len <= 0) {
@@ -1604,11 +1605,12 @@ channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
                                 c->local_consumed += len;
                         }
                 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
-                    FD_ISSET(c->efd, readset)) {
+                    (c->detach_close || FD_ISSET(c->efd, readset))) {
                         len = read(c->efd, buf, sizeof(buf));
                         debug2("channel %d: read %d from efd %d",
                             c->self, len, c->efd);
-                        if (len < 0 && (errno == EINTR || errno == EAGAIN))
+                        if (len < 0 && (errno == EINTR ||
+                            (errno == EAGAIN && !c->detach_close)))
                                 return 1;
                         if (len <= 0) {
                                 debug2("channel %d: closing read-efd %d",
diff --git a/serverloop.c b/serverloop.c
index 69304b5fa..7e373f01b 100644
--- a/serverloop.c
+++ b/serverloop.c
@@ -280,6 +280,7 @@ wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
         struct timeval tv, *tvp;
         int ret;
         int client_alive_scheduled = 0;
+        int program_alive_scheduled = 0;
 
         /*
          * if using client_alive, set the max timeout accordingly,
@@ -317,6 +318,7 @@ wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
                  * the client, try to get some more data from the program.
                  */
                 if (packet_not_very_much_data_to_write()) {
+                        program_alive_scheduled = child_terminated;
                         if (!fdout_eof)
                                 FD_SET(fdout, *readsetp);
                         if (!fderr_eof)
@@ -362,8 +364,16 @@ wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
                 memset(*writesetp, 0, *nallocp);
                 if (errno != EINTR)
                         error("select: %.100s", strerror(errno));
-        } else if (ret == 0 && client_alive_scheduled)
-                client_alive_check();
+        } else {
+                if (ret == 0 && client_alive_scheduled)
+                        client_alive_check();
+                if (!compat20 && program_alive_scheduled && fdin_is_tty) {
+                        if (!fdout_eof)
+                                FD_SET(fdout, *readsetp);
+                        if (!fderr_eof)
+                                FD_SET(fderr, *readsetp);
+                }
+        }
 
         notify_done(*readsetp);
 }
@@ -407,7 +417,8 @@ process_input(fd_set *readset)
         if (!fdout_eof && FD_ISSET(fdout, readset)) {
                 errno = 0;
                 len = read(fdout, buf, sizeof(buf));
-                if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
+                if (len < 0 && (errno == EINTR ||
+                    (errno == EAGAIN && !child_terminated))) {
                         /* do nothing */
 #ifndef PTY_ZEROREAD
                 } else if (len <= 0) {
@@ -425,7 +436,8 @@ process_input(fd_set *readset)
         if (!fderr_eof && FD_ISSET(fderr, readset)) {
                 errno = 0;
                 len = read(fderr, buf, sizeof(buf));
-                if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
+                if (len < 0 && (errno == EINTR ||
+                    (errno == EAGAIN && !child_terminated))) {
                         /* do nothing */
 #ifndef PTY_ZEROREAD
                 } else if (len <= 0) {