cosmopolitan/libc/sock/select.c
Justine Tunney f554dd800e
Make it possible to log kprintf() to file
It's now possible to compile Emacs using cosmocc. However we need to
troubleshoot why it's event loop isn't working correctly at runtime.
2023-06-05 04:16:15 -07:00

93 lines
4 KiB
C

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