hurd: Return EIO on non-responding interrupted servers

since we do not actually know whether the RPC was completed or not,
which makes a huge difference for e.g. write(), so better really error
out than letting caller think that the RPC did not happen.

	* hurd/intr-msg.c (_hurd_intr_rpc_mach_msg): When the server does not
	answer to interrupt_operation, return EIO instead of EINTR.

2 files changed, 11 insertions, 5 deletions

diff --git a/ChangeLog b/ChangeLog
index 79255d3795..7d23aa7236 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,8 @@
 2018-10-28  Samuel Thibault  <samuel.thibault@ens-lyon.org>
 
 	* hurd/hurdsig.c (_hurd_interrupted_rpc_timeout): Set to 60000.
+	* hurd/intr-msg.c (_hurd_intr_rpc_mach_msg): When the server does not
+	answer to interrupt_operation, return EIO instead of EINTR.
 
 2018-10-26  Joseph Myers  <joseph@codesourcery.com>
 
diff --git a/hurd/intr-msg.c b/hurd/intr-msg.c
index 2f83ac6ce7..1f7724ee8b 100644
--- a/hurd/intr-msg.c
+++ b/hurd/intr-msg.c
@@ -141,7 +141,7 @@ _hurd_intr_rpc_mach_msg (mach_msg_header_t *msg,
       else
 	/* The operation was supposedly interrupted, but still has
 	   not returned.  Declare it interrupted.  */
-	goto interrupted;
+	goto dead;
 
     case MACH_SEND_INTERRUPTED: /* RPC didn't get out.  */
       if (!(option & MACH_SEND_MSG))
@@ -324,17 +324,21 @@ _hurd_intr_rpc_mach_msg (mach_msg_header_t *msg,
 	  timeout = user_timeout;
 	  goto message;
 	}
-      /* FALLTHROUGH */
+      err = EINTR;
+
+      /* The EINTR return indicates cancellation, so clear the flag.  */
+      ss->cancel = 0;
+      break;
 
     case MACH_RCV_PORT_DIED:
       /* Server didn't respond to interrupt_operation,
 	 so the signal thread destroyed the reply port.  */
       /* FALLTHROUGH */
 
-    interrupted:
-      err = EINTR;
+    dead:
+      err = EIO;
 
-      /* The EINTR return indicates cancellation, so clear the flag.  */
+      /* The EIO return indicates cancellation, so clear the flag.  */
       ss->cancel = 0;
       break;