* cygwin.din (dup3): Export.

	(pipe2): Export.
	* dtable.cc (dtable::dup_worker): Take additional flags parameter.
	Handle O_CLOEXEC flag.
	(dtable::dup3): Rename from dup2.  Take additional flags parameter.
	Check for valid flags.  Drop check for newfd == oldfd.
	* dtable.h (dtable::dup_worker): Add flags parameter.
	(dtable::dup3): Rename from dup2.
	* fcntl.cc (fcntl64): Add F_DUPFD_CLOEXEC case.
	* fhandler.h (fhandler_mailslot::get_object_attr): Add flags parameter.
	* fhandler.cc (fhandler_base::open): Use security attribute with
	inheritance according to setting of O_CLOEXEC flag.
	* fhandler_console.cc (fhandler_console::open): Ditto.
	* fhandler_fifo.cc (sec_user_cloexec): New inline function to
	create security attribute with inheritance according to setting of
	O_CLOEXEC flag.
	(fhandler_fifo::open): Call sec_user_cloexec to fetch security
	attribute.
	(fhandler_fifo::wait): Ditto.
	* fhandler_mem.cc (fhandler_dev_mem::open): Ditto.
	* fhandler_mailslot.cc (fhandler_mailslot::get_object_attr): Take
	additional flags parameter.  Use security attribute with inheritance
	according to setting of O_CLOEXEC flag.
	(fhandler_mailslot::open): Call get_object_attr with flags parameter.
	* fhandler_registry.cc (fhandler_registry::open): Call set_close_on_exec
	on real handles to accommodate O_CLOEXEC flag.
	* fhandler_tty.cc (fhandler_tty_slave::open): Ditto.
	* fhandler_tape.cc: Create mutex with inheritance according to setting
	of O_CLOEXEC flag.
	* pipe.cc: Replace usage of O_NOINHERIT with O_CLOEXEC.
	 (fhandler_pipe::init): Simplify setting close_on_exec flag.
	(fhandler_pipe::open): Remove setting close_on_exec flag.
	(fhandler_pipe::create): Use security attribute with inheritance
	according to setting of O_CLOEXEC flag.
	(pipe2): New exported function.
	* posix_ipc.cc: Throughout, open backing files with O_CLOEXEC
	flag to follow POSIX semantics.
	* security.h (sec_none_cloexec): New define.
	* syscalls.cc (dup): Add missing extern "C" qualifier.  Accommodate
	renaming of dtable::dup2 to dtable::dup3.
	(dup2): Ditto.  Check newfd == oldfd here.
	(dup3): New function.  Check newfd == oldfd here.
	(open): Set close_on_exec flag according to O_CLOEXEC flag before
	calling fhandler->open.
	* include/cygwin/version.h (CYGWIN_VERSION_API_MINOR): Bump.

1 files changed, 14 insertions, 11 deletions

diff --git a/winsup/cygwin/dtable.cc b/winsup/cygwin/dtable.cc
index ec5d3e386..f0738adc2 100644
--- a/winsup/cygwin/dtable.cc
+++ b/winsup/cygwin/dtable.cc
@@ -559,7 +559,7 @@ build_fh_pc (path_conv& pc, bool set_name)
 }
 
 fhandler_base *
-dtable::dup_worker (fhandler_base *oldfh)
+dtable::dup_worker (fhandler_base *oldfh, int flags)
 {
   /* Don't call set_name in build_fh_pc.  It will be called in
      fhandler_base::operator= below.  Calling it twice will result
@@ -579,7 +579,11 @@ dtable::dup_worker (fhandler_base *oldfh)
 	}
       else
 	{
-	  newfh->close_on_exec (false);
+	  /* The O_CLOEXEC flag enforces close-on-exec behaviour. */
+	  if (flags & O_CLOEXEC)
+	    newfh->set_close_on_exec (true);
+	  else
+	    newfh->close_on_exec (false);
 	  debug_printf ("duped '%s' old %p, new %p", oldfh->get_name (), oldfh->get_io_handle (), newfh->get_io_handle ());
 	}
     }
@@ -587,13 +591,13 @@ dtable::dup_worker (fhandler_base *oldfh)
 }
 
 int
-dtable::dup2 (int oldfd, int newfd)
+dtable::dup3 (int oldfd, int newfd, int flags)
 {
   int res = -1;
   fhandler_base *newfh = NULL;	// = NULL to avoid an incorrect warning
 
   MALLOC_CHECK;
-  debug_printf ("dup2 (%d, %d)", oldfd, newfd);
+  debug_printf ("dup3 (%d, %d, %p)", oldfd, newfd, flags);
   lock ();
 
   if (not_open (oldfd))
@@ -602,21 +606,20 @@ dtable::dup2 (int oldfd, int newfd)
       set_errno (EBADF);
       goto done;
     }
-
   if (newfd < 0)
     {
       syscall_printf ("new fd out of bounds: %d", newfd);
       set_errno (EBADF);
       goto done;
     }
-
-  if (newfd == oldfd)
+  if ((flags & ~O_CLOEXEC) != 0)
     {
-      res = newfd;
-      goto done;
+      syscall_printf ("invalid flags value %x", flags);
+      set_errno (EINVAL);
+      return -1;
     }
 
-  if ((newfh = dup_worker (fds[oldfd])) == NULL)
+  if ((newfh = dup_worker (fds[oldfd], flags)) == NULL)
     {
       res = -1;
       goto done;
@@ -644,7 +647,7 @@ dtable::dup2 (int oldfd, int newfd)
 done:
   MALLOC_CHECK;
   unlock ();
-  syscall_printf ("%d = dup2 (%d, %d)", res, oldfd, newfd);
+  syscall_printf ("%d = dup3 (%d, %d, %p)", res, oldfd, newfd, flags);
 
   return res;
 }