__sigact.c

来自「一个C源代码分析器」· C语言 代码 · 共 70 行

/* Copyright (C) 1991, 1992, 1993, 1994 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 <signal.h>
#include <hurd.h>
#include <hurd/signal.h>

/* If ACT is not NULL, change the action for SIG to *ACT.
   If OACT is not NULL, put the old action for SIG in *OACT.  */
int
DEFUN(__sigaction, (sig, act, oact),
      int sig AND CONST struct sigaction *act AND struct sigaction *oact)
{
  struct hurd_sigstate *ss;
  struct sigaction a, old;

  if (sig <= 0 || sig >= NSIG ||
      (act != NULL && act->sa_handler != SIG_DFL &&
       ((__sigmask (sig) & _SIG_CANT_MASK) ||
	act->sa_handler == SIG_ERR)))
    {
      errno = EINVAL;
      return -1;
    }

  /* Copy so we fault before taking locks.  */
  if (act != NULL)
    a = *act;

  ss = _hurd_self_sigstate ();
  ss->critical_section = 1;

  if (act != NULL && sig == SIGCHLD)
    /* Inform the proc server whether or not it should send us SIGCHLD for
       stopped children.  We do this with SS->lock held so that no SIGCHLD
       can arrive in the middle and be of indeterminate status.  */
    __USEPORT (PROC,
	       __proc_mod_stopchild (port, !(a.sa_flags & SA_NOCLDSTOP)));

  old = ss->actions[sig];

  if (act != NULL)
    ss->actions[sig] = a;

  ss->critical_section = 0;
  __mutex_unlock (&ss->lock);

  if (oact != NULL)
    *oact = old;

  return 0;
}