1 /* Copyright (C) 1996-2021 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 Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the 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 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18 #include <errno.h>
19 #include <hurd.h>
20 #include <hurd/signal.h>
21 #include <hurd/msg.h>
22 #include <hurd/sigpreempt.h>
23 #include <assert.h>
24 #include <sysdep-cancel.h>
25
26 /* Select any of pending signals from SET or wait for any to arrive. */
27 int
__sigwait(const sigset_t * set,int * sig)28 __sigwait (const sigset_t *set, int *sig)
29 {
30 struct hurd_sigstate *ss;
31 sigset_t mask, ready, blocked;
32 int signo = 0;
33 struct hurd_signal_preemptor preemptor;
34 jmp_buf buf;
35 mach_port_t wait;
36 mach_msg_header_t msg;
37 int cancel_oldtype;
38
39 sighandler_t
40 preempt_fun (struct hurd_signal_preemptor *pe,
41 struct hurd_sigstate *ss,
42 int *sigp,
43 struct hurd_signal_detail *detail)
44 {
45 if (signo)
46 /* We've already been run; don't interfere. */
47 return SIG_ERR;
48
49 signo = *sigp;
50
51 /* Make sure this is all kosher */
52 assert (__sigismember (&mask, signo));
53
54 /* Restore the blocking mask. */
55 ss->blocked = blocked;
56
57 return pe->handler;
58 }
59
60 void
61 handler (int sig)
62 {
63 assert (sig == signo);
64 longjmp (buf, 1);
65 }
66
67 wait = __mach_reply_port ();
68
69 if (set != NULL)
70 /* Crash before locking */
71 mask = *set;
72 else
73 __sigemptyset (&mask);
74
75 ss = _hurd_self_sigstate ();
76 cancel_oldtype = LIBC_CANCEL_ASYNC();
77 _hurd_sigstate_lock (ss);
78
79 /* See if one of these signals is currently pending. */
80 sigset_t pending = _hurd_sigstate_pending (ss);
81 __sigandset (&ready, &pending, &mask);
82 if (! __sigisemptyset (&ready))
83 {
84 for (signo = 1; signo < NSIG; signo++)
85 if (__sigismember (&ready, signo))
86 {
87 __sigdelset (&ready, signo);
88 goto all_done;
89 }
90 /* Huh? Where'd it go? */
91 abort ();
92 }
93
94 /* Wait for one of them to show up. */
95
96 if (!setjmp (buf))
97 {
98 /* Make the preemptor */
99 preemptor.signals = mask;
100 preemptor.first = 0;
101 preemptor.last = -1;
102 preemptor.preemptor = preempt_fun;
103 preemptor.handler = handler;
104
105 /* Install this preemptor */
106 preemptor.next = ss->preemptors;
107 ss->preemptors = &preemptor;
108
109 /* Unblock the expected signals */
110 blocked = ss->blocked;
111 ss->blocked &= ~mask;
112
113 _hurd_sigstate_unlock (ss);
114
115 /* Wait. */
116 __mach_msg (&msg, MACH_RCV_MSG, 0, sizeof (msg), wait,
117 MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
118 abort ();
119 }
120 else
121 {
122 assert (signo);
123
124 _hurd_sigstate_lock (ss);
125
126 /* Delete our preemptor. */
127 assert (ss->preemptors == &preemptor);
128 ss->preemptors = preemptor.next;
129 }
130
131
132 all_done:
133 _hurd_sigstate_unlock (ss);
134 LIBC_CANCEL_RESET (cancel_oldtype);
135
136 __mach_port_destroy (__mach_task_self (), wait);
137 *sig = signo;
138 return 0;
139 }
140
141 libc_hidden_def (__sigwait)
142 weak_alias (__sigwait, sigwait)
143