1/* Copyright (C) 2006-2022 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 <limits.h>
20#include <signal.h>
21#include <stddef.h> /* For NULL. */
22#include <sys/poll.h>
23#include <sysdep-cancel.h>
24#include <time.h>
25
26
27int
28ppoll (struct pollfd *fds, nfds_t nfds, const struct timespec *timeout,
29 const sigset_t *sigmask)
30{
31 int tval = -1;
32
33 /* poll uses a simple millisecond value. Convert it. */
34 if (timeout != NULL)
35 {
36 if (timeout->tv_sec < 0 || ! valid_nanoseconds (ns: timeout->tv_nsec))
37 {
38 __set_errno (EINVAL);
39 return -1;
40 }
41
42 if (timeout->tv_sec > INT_MAX / 1000
43 || (timeout->tv_sec == INT_MAX / 1000
44 && ((timeout->tv_nsec + 999999) / 1000000 > INT_MAX % 1000)))
45 /* We cannot represent the timeout in an int value. Wait
46 forever. */
47 tval = -1;
48 else
49 tval = (timeout->tv_sec * 1000
50 + (timeout->tv_nsec + 999999) / 1000000);
51 }
52
53 /* The setting and restoring of the signal mask and the select call
54 should be an atomic operation. This can't be done without kernel
55 help. */
56 sigset_t savemask;
57 if (sigmask != NULL)
58 __sigprocmask (SIG_SETMASK, set: sigmask, oset: &savemask);
59
60 /* Note the ppoll() is a cancellation point. But since we call
61 poll() which itself is a cancellation point we do not have
62 to do anything here. */
63 int retval = __poll (fds: fds, nfds: nfds, timeout: tval);
64
65 if (sigmask != NULL)
66 __sigprocmask (SIG_SETMASK, set: &savemask, NULL);
67
68 return retval;
69}
70
71#ifndef ppoll
72libc_hidden_def (ppoll);
73#endif
74

source code of glibc/io/ppoll.c