set close-on-exec bit on pipe() FDs

p4raw-id: //depot/perl@2215

3 files changed, 12 insertions, 3 deletions

diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod
index e72624faa0..5a9543ff45 100644
--- a/pod/perlfunc.pod
+++ b/pod/perlfunc.pod
@@ -2394,7 +2394,9 @@ See L<perlipc/"Safe Pipe Opens"> for more examples of this.
 
 NOTE: On any operation that may do a fork, any unflushed buffers remain
 unflushed in both processes, which means you may need to set C<$|> to
-avoid duplicate output.
+avoid duplicate output.  On systems that support a close-on-exec flag on
+files, the flag will be set for the newly opened file descriptor as
+determined by the value of $^F.  See L<perlvar/$^F>.
 
 Closing any piped filehandle causes the parent process to wait for the
 child to finish, and returns the status value in C<$?>.
@@ -2614,6 +2616,10 @@ after each command, depending on the application.
 See L<IPC::Open2>, L<IPC::Open3>, and L<perlipc/"Bidirectional Communication">
 for examples of such things.
 
+On systems that support a close-on-exec flag on files, the flag will be set
+for the newly opened file descriptors as determined by the value of $^F.
+See L<perlvar/$^F>.
+
 =item pop ARRAY
 
 =item pop
diff --git a/pod/perlvar.pod b/pod/perlvar.pod
index af5f62f74b..38fd1684ee 100644
--- a/pod/perlvar.pod
+++ b/pod/perlvar.pod
@@ -667,7 +667,7 @@ descriptors are not.  Also, during an open(), system file descriptors are
 preserved even if the open() fails.  (Ordinary file descriptors are
 closed before the open() is attempted.)  Note that the close-on-exec
 status of a file descriptor will be decided according to the value of
-C<$^F> at the time of the open, not the time of the exec.
+C<$^F> when the open() or pipe() was called, not the time of the exec().
 
 =item $^H
 
diff --git a/pp_sys.c b/pp_sys.c
index 7ae628bfb2..96ecd5875c 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -572,7 +572,10 @@ PP(pp_pipe_op)
 	else PerlLIO_close(fd[1]);
 	goto badexit;
     }
-
+#if defined(HAS_FCNTL) && defined(F_SETFD)
+    fcntl(fd[0],F_SETFD,fd[0] > PL_maxsysfd);	/* ensure close-on-exec */
+    fcntl(fd[1],F_SETFD,fd[1] > PL_maxsysfd);	/* ensure close-on-exec */
+#endif
     RETPUSHYES;
 
 badexit: