1  /* Implementation of sigtimedwait function from POSIX.1b.
       2     Copyright (C) 1996-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <errno.h>
      20  #include <hurd.h>
      21  #include <hurd/signal.h>
      22  #include <hurd/msg.h>
      23  #include <hurd/sigpreempt.h>
      24  #include <assert.h>
      25  #include <sysdep-cancel.h>
      26  
      27  int
      28  __sigtimedwait (const sigset_t *set, siginfo_t *info,
      29  		const struct timespec *timeout)
      30  {
      31    struct hurd_sigstate *ss;
      32    sigset_t mask, ready, blocked;
      33    int signo = 0;
      34    struct hurd_signal_preemptor preemptor;
      35    jmp_buf buf;
      36    mach_port_t wait;
      37    mach_msg_header_t msg;
      38    int cancel_oldtype;
      39    mach_msg_option_t option = 0;
      40    mach_msg_timeout_t ms = MACH_MSG_TIMEOUT_NONE;
      41  
      42    sighandler_t
      43      preempt_fun (struct hurd_signal_preemptor *pe,
      44  		 struct hurd_sigstate *ss,
      45  		 int *sigp,
      46  		 struct hurd_signal_detail *detail)
      47      {
      48        if (signo)
      49  	/* We've already been run; don't interfere. */
      50  	return SIG_ERR;
      51  
      52        signo = *sigp;
      53  
      54        if (info)
      55  	{
      56  	  info->si_signo = signo;
      57  	  info->si_errno = detail->error;
      58  	  info->si_code = detail->code;
      59  
      60  	  /* XXX */
      61  	  info->si_pid = -1;
      62  	  info->si_uid = -1;
      63  	  info->si_addr = (void *) NULL;
      64  	  info->si_status = 0;
      65  	  info->si_band = 0;
      66  	  info->si_value.sival_int = 0;
      67  	}
      68  
      69        /* Make sure this is all kosher */
      70        assert (__sigismember (&mask, signo));
      71  
      72        /* Restore the blocking mask. */
      73        ss->blocked = blocked;
      74  
      75        return pe->handler;
      76      }
      77  
      78    void
      79      handler (int sig)
      80      {
      81        assert (sig == signo);
      82        longjmp (buf, 1);
      83      }
      84  
      85    wait = __mach_reply_port ();
      86  
      87    if (set != NULL)
      88      /* Crash before locking */
      89      mask = *set;
      90    else
      91      __sigemptyset (&mask);
      92  
      93    ss = _hurd_self_sigstate ();
      94    cancel_oldtype = LIBC_CANCEL_ASYNC();
      95    _hurd_sigstate_lock (ss);
      96  
      97    /* See if one of these signals is currently pending.  */
      98    sigset_t pending = _hurd_sigstate_pending (ss);
      99    __sigandset (&ready, &pending, &mask);
     100    if (! __sigisemptyset (&ready))
     101      {
     102        for (signo = 1; signo < NSIG; signo++)
     103  	if (__sigismember (&ready, signo))
     104  	  {
     105  	    __sigdelset (&ready, signo);
     106  	    goto all_done;
     107  	  }
     108        /* Huh?  Where'd it go? */
     109        abort ();
     110      }
     111  
     112    /* Wait for one of them to show up.  */
     113  
     114    if (!setjmp (buf))
     115      {
     116        /* Make the preemptor */
     117        preemptor.signals = mask;
     118        preemptor.first = 0;
     119        preemptor.last = -1;
     120        preemptor.preemptor = preempt_fun;
     121        preemptor.handler = handler;
     122  
     123        /* Install this preemptor */
     124        preemptor.next = ss->preemptors;
     125        ss->preemptors = &preemptor;
     126  
     127        /* Unblock the expected signals */
     128        blocked = ss->blocked;
     129        ss->blocked &= ~mask;
     130  
     131        _hurd_sigstate_unlock (ss);
     132  
     133        if (timeout)
     134  	{
     135  	  option |= MACH_RCV_TIMEOUT,
     136  	  ms = timeout->tv_sec * 1000
     137  	     + (timeout->tv_nsec + 999999) / 1000000;
     138  	}
     139  
     140        /* Wait.  */
     141        __mach_msg (&msg, MACH_RCV_MSG | option, 0, sizeof (msg), wait,
     142  		  ms, MACH_PORT_NULL);
     143  
     144        if (!(option & MACH_RCV_TIMEOUT))
     145          abort ();
     146  
     147        /* Timed out.  */
     148        signo = __hurd_fail (EAGAIN);
     149      }
     150    else
     151      {
     152        assert (signo);
     153  
     154        _hurd_sigstate_lock (ss);
     155  
     156        /* Delete our preemptor. */
     157        assert (ss->preemptors == &preemptor);
     158        ss->preemptors = preemptor.next;
     159      }
     160  
     161  
     162  all_done:
     163    _hurd_sigstate_unlock (ss);
     164    LIBC_CANCEL_RESET (cancel_oldtype);
     165  
     166    __mach_port_destroy (__mach_task_self (), wait);
     167    return signo;
     168  }
     169  libc_hidden_def (__sigtimedwait)
     170  weak_alias (__sigtimedwait, sigtimedwait)