1 files changed, 41 insertions, 12 deletions
diff --git a/sysdeps/mach/hurd/fcntl.c b/sysdeps/mach/hurd/fcntl.c
index a65c190..de576af 100644
--- a/sysdeps/mach/hurd/fcntl.c
+++ b/sysdeps/mach/hurd/fcntl.c
@@ -83,18 +83,47 @@ __libc_fcntl (int fd, int cmd, ...)
 	  result = -1;
 	else
 	  {
-	    /* Give the ports each a user ref for the new descriptor.  */
-	    __mach_port_mod_refs (__mach_task_self (), port,
-				  MACH_PORT_RIGHT_SEND, 1);
-	    if (ctty != MACH_PORT_NULL)
-	      __mach_port_mod_refs (__mach_task_self (), ctty,
-				    MACH_PORT_RIGHT_SEND, 1);
-
-	    /* Install the ports and flags in the new descriptor.  */
-	    if (ctty != MACH_PORT_NULL)
-	      _hurd_port_set (&new->ctty, ctty);
-	    new->flags = flags;
-	    _hurd_port_locked_set (&new->port, port); /* Unlocks NEW.  */
+	    /* Give the io server port a user ref for the new descriptor.  */
+	    err = __mach_port_mod_refs (__mach_task_self (), port,
+					MACH_PORT_RIGHT_SEND, 1);
+
+	    if (err == KERN_UREFS_OVERFLOW)
+	      result = __hurd_fail (EMFILE);
+	    else if (err)
+	      result = __hurd_fail (EINVAL);
+	    else if (ctty != MACH_PORT_NULL)
+	      {
+		/* We have confirmed the io server port has got a user ref
+		   count, now give ctty port a user ref for the new
+		   descriptor.  */
+		err = __mach_port_mod_refs (__mach_task_self (), ctty,
+					    MACH_PORT_RIGHT_SEND, 1);
+
+		if (err)
+		  {
+		    /* In this case the io server port has got a ref count
+		    but the ctty port fails to get one, so we need to clean
+		    the ref count we just assigned.  */
+		    __mach_port_mod_refs (__mach_task_self (), port,
+					  MACH_PORT_RIGHT_SEND, -1);
+
+		    if (err == KERN_UREFS_OVERFLOW)
+		      result = __hurd_fail (EMFILE);
+		    else
+		      result = __hurd_fail (EINVAL);
+		  }
+	      }
+
+	    if (!err)
+	      {
+		/* The ref counts of the ports are incremented successfully.  */
+		/* Install the ports and flags in the new descriptor.  */
+		if (ctty != MACH_PORT_NULL)
+		  _hurd_port_set (&new->ctty, ctty);
+		new->flags = flags;
+		/* Unlocks NEW.  */
+		_hurd_port_locked_set (&new->port, port);
+	      }
 	  }
 
 	HURD_CRITICAL_END;