1//===-- Implementation of poll --------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "src/poll/poll.h"
10
11#include "hdr/types/nfds_t.h"
12#include "hdr/types/struct_pollfd.h"
13#include "hdr/types/struct_timespec.h"
14#include "src/__support/OSUtil/syscall.h" // syscall_impl
15#include "src/__support/common.h"
16#include "src/__support/libc_errno.h"
17#include "src/__support/macros/config.h"
18
19#include <sys/syscall.h> // SYS_poll, SYS_ppoll
20
21namespace LIBC_NAMESPACE_DECL {
22
23LLVM_LIBC_FUNCTION(int, poll, (pollfd * fds, nfds_t nfds, int timeout)) {
24 int ret = 0;
25
26#if defined(SYS_poll)
27 ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_poll, fds, nfds, timeout);
28#else // no SYS_poll
29 timespec ts, *tsp;
30 if (timeout >= 0) {
31 ts.tv_sec = timeout / 1000;
32 ts.tv_nsec = (timeout % 1000) * 1000000;
33 tsp = &ts;
34 } else {
35 tsp = nullptr;
36 }
37#if defined(SYS_ppoll)
38 ret =
39 LIBC_NAMESPACE::syscall_impl<int>(SYS_ppoll, fds, nfds, tsp, nullptr, 0);
40#elif defined(SYS_ppoll_time64)
41 ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_ppoll_time64, fds, nfds, tsp,
42 nullptr, 0);
43#else
44#error "poll, ppoll, ppoll_time64 syscalls not available."
45#endif // defined(SYS_ppoll) || defined(SYS_ppoll_time64)
46#endif // defined(SYS_poll)
47
48 if (ret < 0) {
49 libc_errno = -ret;
50 return -1;
51 }
52 return ret;
53}
54
55} // namespace LIBC_NAMESPACE_DECL
56

source code of libc/src/poll/linux/poll.cpp