initial import

sysdeps/mach/hurd/sigaltstack.c

@@ -0,0 +1,62 @@
+/* Copyright (C) 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <errno.h>
+#include <hurd.h>
+#include <hurd/signal.h>
+
+/* Run signals handlers on the stack specified by SS (if not NULL).
+   If OSS is not NULL, it is filled in with the old signal stack status.  */
+int
+DEFUN(sigaltstack, (ss, oss),
+      CONST struct sigaltstack *argss AND struct sigaltstack *oss)
+{
+  struct hurd_sigstate *s;
+  struct sigaltstack ss, old;
+
+  /* Fault before taking any locks.  */
+  if (argss != NULL)
+    ss = *argss;
+  if (oss != NULL)
+    *(volatile struct sigaltstack *) oss = *oss;
+
+  s = _hurd_self_sigstate ();
+  __spin_lock (&s->lock);
+
+  if (argss != NULL &&
+      (ss.ss_flags & SA_DISABLE) && (s->sigaltstack.ss_flags & SA_ONSTACK))
+    {
+      /* Can't disable a stack that is in use.  */
+      __spin_unlock (&s->lock);
+      errno = EINVAL;
+      return -1;
+    }
+
+  old = s->sigaltstack;
+
+  if (argss != NULL)
+    s->sigaltstack = ss;
+
+  __spin_unlock (&s->lock);
+
+  if (oss != NULL)
+    *oss = old;
+
+  return 0;
+}