about summary refs log tree commit diff
path: root/sysdeps/mach/hurd/sigwait.c
blob: 9d2dfe13ee392f07fb2b468c46bd3d211f9e20aa (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
/* Copyright (C) 1996-2022 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 Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <hurd.h>
#include <hurd/signal.h>
#include <hurd/msg.h>
#include <hurd/sigpreempt.h>
#include <assert.h>
#include <sysdep-cancel.h>

/* Select any of pending signals from SET or wait for any to arrive.  */
int
__sigwait (const sigset_t *set, int *sig)
{
  struct hurd_sigstate *ss;
  sigset_t mask, ready, blocked;
  int signo = 0;
  struct hurd_signal_preemptor preemptor;
  jmp_buf buf;
  mach_port_t wait;
  mach_msg_header_t msg;
  int cancel_oldtype;

  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));

      /* Restore the blocking mask. */
      ss->blocked = blocked;

      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 ();
  cancel_oldtype = LIBC_CANCEL_ASYNC();
  _hurd_sigstate_lock (ss);

  /* See if one of these signals is currently pending.  */
  sigset_t pending = _hurd_sigstate_pending (ss);
  __sigandset (&ready, &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;

      /* Unblock the expected signals */
      blocked = ss->blocked;
      ss->blocked &= ~mask;

      _hurd_sigstate_unlock (ss);

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

      _hurd_sigstate_lock (ss);

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


all_done:
  _hurd_sigstate_unlock (ss);
  LIBC_CANCEL_RESET (cancel_oldtype);

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

libc_hidden_def (__sigwait)
weak_alias (__sigwait, sigwait)