[PATCH,HURD] hurdselect: let select get interrupted by signals

[Samuel Thibault]

Hello,

This lets select get interrupted by signals: without passing
MACH_RCV_INTERRUPT to __mach_msg, it would just loop again on signal
delivery. Worse, the timeout would be reused as such (as documented
for mach_msg), leading to potential infinite loop when getting
frequent-enough signals.

This patch syntaxically depends on my previous one, but it's actually
independent.  The important point is just that the handling code is
before the test for if(got), so that getting interrupted after having
gotten some answers will keep err set to 0.

Samuel

hurdselect: let select get interrupted by signals

* hurd/hurdselect.c (_hurd_select): Pass MACH_RCV_INTERRUPT to
__mach_msg.  If that returns MACH_RCV_INTERRUPTED, set ERR to EINTR.

diff --git a/hurd/hurdselect.c b/hurd/hurdselect.c
index 974c3c3..fae21a2 100644
--- a/hurd/hurdselect.c
+++ b/hurd/hurdselect.c
@@ -335,7 +335,7 @@ _hurd_select (int nfds,
       mach_msg_option_t options = (timeout == NULL ? 0 : MACH_RCV_TIMEOUT);
       error_t msgerr;
       while ((msgerr = __mach_msg (&msg.head,
-                                  MACH_RCV_MSG | options,
+                                  MACH_RCV_MSG | MACH_RCV_INTERRUPT | options,
                                   0, sizeof msg, portset, to,
                                   MACH_PORT_NULL)) == MACH_MSG_SUCCESS)
        {
@@ -407,6 +407,10 @@ _hurd_select (int nfds,
            }
        }
 
+      if (msgerr == MACH_RCV_INTERRUPTED)
+       /* Interruption on our side (e.g. signal reception).  */
+       err = EINTR;
+
       if (got)
        /* At least one descriptor is known to be ready now, so we will
           return success.  */