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94 lines
4 KiB
C
94 lines
4 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/sock/select.h"
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#include "libc/calls/cp.internal.h"
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#include "libc/calls/struct/itimerval.internal.h"
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#include "libc/calls/struct/timespec.h"
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#include "libc/calls/struct/timeval.h"
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#include "libc/calls/struct/timeval.internal.h"
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#include "libc/dce.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/intrin/describeflags.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/sock/internal.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Does what poll() does except with bitset API.
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*
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* This system call is supported on all platforms. However, on Windows,
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* this is polyfilled to translate into poll(). So it's recommended that
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* poll() be used instead.
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*
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* @raise ECANCELED if thread was cancelled in masked mode
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* @raise EINTR if signal was delivered
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* @cancellationpoint
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* @asyncsignalsafe
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* @threadsafe
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* @norestart
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*/
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int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
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struct timeval *timeout) {
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int rc;
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struct timeval tv, *tvp;
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POLLTRACE("select(%d, %p, %p, %p, %s) → ...", nfds, readfds, writefds,
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exceptfds, DescribeTimeval(0, timeout));
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// the linux kernel modifies timeout
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if (timeout) {
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if (IsAsan() && !__asan_is_valid(timeout, sizeof(*timeout))) {
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return efault();
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}
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tv = *timeout;
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tvp = &tv;
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} else {
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tvp = 0;
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}
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BEGIN_CANCELLATION_POINT;
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if (nfds < 0) {
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rc = einval();
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} else if (IsAsan() &&
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((readfds && !__asan_is_valid(readfds, FD_SIZE(nfds))) ||
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(writefds && !__asan_is_valid(writefds, FD_SIZE(nfds))) ||
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(exceptfds && !__asan_is_valid(exceptfds, FD_SIZE(nfds))))) {
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rc = efault();
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} else if (!IsWindows()) {
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#ifdef __aarch64__
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struct timespec ts, *tsp;
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if (timeout) {
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ts.tv_sec = timeout->tv_sec;
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ts.tv_nsec = timeout->tv_usec * 1000;
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tsp = &ts;
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} else {
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tsp = 0;
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}
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rc = sys_pselect(nfds, readfds, writefds, exceptfds, tsp, 0);
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#else
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rc = sys_select(nfds, readfds, writefds, exceptfds, tvp);
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#endif
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} else {
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rc = sys_select_nt(nfds, readfds, writefds, exceptfds, tvp, 0);
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}
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END_CANCELLATION_POINT;
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POLLTRACE("select(%d, %p, %p, %p, [%s]) → %d% m", nfds, readfds, writefds,
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exceptfds, DescribeTimeval(rc, tvp), rc);
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return rc;
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}
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