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glibc  2.9
Functions
sigwait.c File Reference
#include <errno.h>
#include <hurd.h>
#include <hurd/signal.h>
#include <hurd/msg.h>
#include <hurd/sigpreempt.h>
#include <assert.h>

Go to the source code of this file.

Functions

int __sigwait (const sigset_t *set, int *sig)

Function Documentation

int __sigwait ( const sigset_t set,
int sig 
)

Definition at line 28 of file sigwait.c.

{
  struct hurd_sigstate *ss;
  sigset_t mask, ready;
  int signo = 0;
  struct hurd_signal_preemptor preemptor;
  jmp_buf buf;
  mach_port_t wait;
  mach_msg_header_t msg;

  sighandler_t
    preempt_fun (struct hurd_signal_preemptor *pe,
               struct hurd_sigstate *ss,
               int *sigp,
               struct hurd_signal_detail *detail)
    {
      if (signo)
       /* We've already been run; don't interfere. */
       return SIG_ERR;

      signo = *sigp;

      /* Make sure this is all kosher */
      assert (__sigismember (&mask, signo));

      /* Make sure this signal is unblocked */
      __sigdelset (&ss->blocked, signo);

      return pe->handler;
    }

  void
    handler (int sig)
    {
      assert (sig == signo);
      longjmp (buf, 1);
    }

  wait = __mach_reply_port ();

  if (set != NULL)
    /* Crash before locking */
    mask = *set;
  else
    __sigemptyset (&mask);

  ss = _hurd_self_sigstate ();
  __spin_lock (&ss->lock);

  /* See if one of these signals is currently pending.  */
  __sigandset (&ready, &ss->pending, &mask);
  if (! __sigisemptyset (&ready))
    {
      for (signo = 1; signo < NSIG; signo++)
       if (__sigismember (&ready, signo))
         {
           __sigdelset (&ready, signo);
           goto all_done;
         }
      /* Huh?  Where'd it go? */
      abort ();
    }

  /* Wait for one of them to show up.  */

  if (!setjmp (buf))
    {
      /* Make the preemptor */
      preemptor.signals = mask;
      preemptor.first = 0;
      preemptor.last = -1;
      preemptor.preemptor = preempt_fun;
      preemptor.handler = handler;

      /* Install this preemptor */
      preemptor.next = ss->preemptors;
      ss->preemptors = &preemptor;

      __spin_unlock (&ss->lock);

      /* Wait. */
      __mach_msg (&msg, MACH_RCV_MSG, 0, sizeof (msg), wait,
                MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
      abort ();
    }
  else
    {
      assert (signo);

      __spin_lock (&ss->lock);

      /* Delete our preemptor. */
      assert (ss->preemptors == &preemptor);
      ss->preemptors = preemptor.next;
    }


all_done:
  spin_unlock (&ss->lock);

  __mach_port_destroy (__mach_task_self (), wait);
  *sig = signo;
  return 0;
}

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