sysdeps/mach/hurd/sigaction.c

   1 /* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <errno.h>
  21 #include <signal.h>
  22 #include <hurd.h>
  23 #include <hurd/signal.h>
  24
  25 /* If ACT is not NULL, change the action for SIG to *ACT.
  26    If OACT is not NULL, put the old action for SIG in *OACT.  */
  27 int
  28 DEFUN(__sigaction, (sig, act, oact),
  29       int sig AND CONST struct sigaction *act AND struct sigaction *oact)
  30 {
  31   struct hurd_sigstate *ss;
  32   struct sigaction a, old;
  33   sigset_t pending;
  34
  35   if (sig <= 0 || sig >= NSIG ||
  36       (act != NULL && act->sa_handler != SIG_DFL &&
  37        ((__sigmask (sig) & _SIG_CANT_MASK) ||
  38         act->sa_handler == SIG_ERR)))
  39     {
  40       errno = EINVAL;
  41       return -1;
  42     }
  43
  44   /* Copy so we fault before taking locks.  */
  45   if (act != NULL)
  46     a = *act;
  47
  48   ss = _hurd_self_sigstate ();
  49
  50   __spin_lock (&ss->lock);
  51   old = ss->actions[sig];
  52   if (act != NULL)
  53     ss->actions[sig] = a;
  54
  55   if (act != NULL && sig == SIGCHLD &&
  56       (a.sa_flags & SA_NOCLDSTOP) != (old.sa_flags & SA_NOCLDSTOP))
  57     {
  58       ss->critical_section = 1;
  59       __spin_unlock (&ss->lock);
  60
  61       /* Inform the proc server whether or not it should send us SIGCHLD for
  62          stopped children.  We do this in a critical section so that no
  63          SIGCHLD can arrive in the middle and be of indeterminate status.  */
  64       __USEPORT (PROC,
  65                  __proc_mod_stopchild (port, !(a.sa_flags & SA_NOCLDSTOP)));
  66
  67       __spin_lock (&ss->lock);
  68       ss->critical_section = 0;
  69       pending = ss->pending & ~ss->blocked;
  70     }
  71   else
  72     pending = 0;
  73
  74   __spin_unlock (&ss->lock);
  75
  76   if (pending)
  77     __msg_sig_post (_hurd_msgport, 0, __mach_task_self ());
  78
  79   if (oact != NULL)
  80     *oact = old;
  81
  82   return 0;
  83 }
  84
  85 weak_alias (__sigaction, sigaction)