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, 4 insertions, 0 deletions

diff --git a/hurd/hurdfchdir.c b/hurd/hurdfchdir.c
index 62a6ed1638..84dc292580 100644
--- a/hurd/hurdfchdir.c
+++ b/hurd/hurdfchdir.c
@@ -32,6 +32,7 @@ _hurd_change_directory_port_from_fd (struct hurd_port *portcell, int fd)
   if (!d)
     return __hurd_fail (EBADF);
 
+retry:
   HURD_CRITICAL_BEGIN;
 
   ret = HURD_PORT_USE (&d->port,
@@ -53,6 +54,9 @@ _hurd_change_directory_port_from_fd (struct hurd_port *portcell, int fd)
 		       }));
 
   HURD_CRITICAL_END;
+  if (ret == -1 && errno == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   return ret;
 }