[vte] spawn: Don't allow G_SPAWN_LEAVE_DESCRIPTORS_OPEN flag

[Christian Persch <chpe src gnome org>]

commit ca705122f1638cbf8c4119ff6bfab7e974e01256
Author: Christian Persch <chpe gnome org>
Date:   Thu Jan 14 17:05:33 2016 +0100

    spawn: Don't allow G_SPAWN_LEAVE_DESCRIPTORS_OPEN flag
    
    If you do want to pass a FD to the child, use a child setup
    function that unsets the FD_CLOEXEC flag.

 src/vte.cc    |   10 ++++++----
 src/vtegtk.cc |    7 ++++---
 2 files changed, 10 insertions(+), 7 deletions(-)
---
diff --git a/src/vte.cc b/src/vte.cc
index 570f122..e6f4bcb 100644
--- a/src/vte.cc
+++ b/src/vte.cc
@@ -3600,10 +3600,6 @@ VteTerminalPrivate::watch_child (GPid child_pid)
  *
  * Note that %G_SPAWN_DO_NOT_REAP_CHILD will always be added to @spawn_flags.
  *
- * Note that unless @spawn_flags contains %G_SPAWN_LEAVE_DESCRIPTORS_OPEN, all file
- * descriptors except stdin/stdout/stderr will be closed before calling exec()
- * in the child.
- *
  * See vte_pty_new(), g_spawn_async() and vte_terminal_watch_child() for more information.
  *
  * Returns: %TRUE on success, or %FALSE on error with @error filled in
@@ -3635,6 +3631,12 @@ VteTerminalPrivate::spawn_sync(VtePtyFlags pty_flags,
         /* FIXMEchpe: is this flag needed */
         spawn_flags |= G_SPAWN_CHILD_INHERITS_STDIN;
 
+        /* We do NOT support this flag. If you want to have some FD open in the child
+         * process, simply use a child setup function that unsets the CLOEXEC flag
+         * on that FD.
+         */
+        spawn_flags &= ~G_SPAWN_LEAVE_DESCRIPTORS_OPEN;
+
         if (!__vte_pty_spawn(new_pty,
                              working_directory,
                              argv,
diff --git a/src/vtegtk.cc b/src/vtegtk.cc
index 3e62eec..fb14d46 100644
--- a/src/vtegtk.cc
+++ b/src/vtegtk.cc
@@ -2208,9 +2208,10 @@ vte_terminal_watch_child (VteTerminal *terminal,
  *
  * Note that %G_SPAWN_DO_NOT_REAP_CHILD will always be added to @spawn_flags.
  *
- * Note that unless @spawn_flags contains %G_SPAWN_LEAVE_DESCRIPTORS_OPEN, all file
- * descriptors except stdin/stdout/stderr will be closed before calling exec()
- * in the child.
+ * Note that all open file descriptors will be closed in the child. If you want
+ * to keep some file descriptor open for use in the child process, you need to
+ * use a child setup function that unsets the FD_CLOEXEC flag on that file
+ * descriptor.
  *
  * See vte_pty_new(), g_spawn_async() and vte_terminal_watch_child() for more information.
  *