hurd: handle EINTR during critical sections

During critical sections, signal handling is deferred and thus RPCs return
EINTR, even if SA_RESTART is set. We thus have to restart the whole critical
section in that case.

This also adds HURD_CRITICAL_UNLOCK in the cases where one wants to
break the section in the middle.

1 files changed, 14 insertions, 1 deletions

diff --git a/sysdeps/mach/hurd/spawni.c b/sysdeps/mach/hurd/spawni.c
index 9bc1571c29..b5c92365f2 100644
--- a/sysdeps/mach/hurd/spawni.c
+++ b/sysdeps/mach/hurd/spawni.c
@@ -333,6 +333,7 @@ __spawni (pid_t *pid, const char *file,
 
   ss = _hurd_self_sigstate ();
 
+retry:
   assert (! __spin_lock_locked (&ss->critical_section_lock));
   __spin_lock (&ss->critical_section_lock);
 
@@ -437,7 +438,19 @@ __spawni (pid_t *pid, const char *file,
 						 MACH_PORT_RIGHT_SEND, +1));
 
   if (err)
-    goto out;
+    {
+      _hurd_critical_section_unlock (ss);
+
+      if (err == EINTR)
+	{
+	  /* Got a signal while inside an RPC of the critical section, retry again */
+	  __mach_port_deallocate (__mach_task_self (), auth);
+	  auth = MACH_PORT_NULL;
+	  goto retry;
+	}
+
+      goto out;
+    }
 
   /* Pack up the descriptor table to give the new program.
      These descriptors will need to be reauthenticated below