cosmopolitan/libc/sock/pselect.c
Justine Tunney 0d748ad58e
Fix warnings
This change fixes Cosmopolitan so it has fewer opinions about compiler
warnings. The whole repository had to be cleaned up to be buildable in
-Werror -Wall mode. This lets us benefit from things like strict const
checking. Some actual bugs might have been caught too.
2023-09-01 20:50:18 -07:00

109 lines
4.7 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 2022 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/calls/cp.internal.h"
#include "libc/calls/struct/itimerval.internal.h"
#include "libc/calls/struct/sigset.internal.h"
#include "libc/calls/struct/timespec.h"
#include "libc/calls/struct/timespec.internal.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/sock/select.h"
#include "libc/sysv/consts/nrlinux.h"
#include "libc/sysv/errfuns.h"
/**
* Does what poll() does except with bitset API.
*
* This function is the same as saying:
*
* sigset_t old;
* sigprocmask(SIG_SETMASK, sigmask, &old);
* select(nfds, readfds, writefds, exceptfds, timeout);
* sigprocmask(SIG_SETMASK, old, 0);
*
* Except it happens atomically.
*
* The Linux Kernel modifies the timeout parameter. This wrapper gives
* it a local variable due to POSIX requiring that `timeout` be const.
* If you need that information from the Linux Kernel use sys_pselect.
*
* This system call is supported on all platforms. It's like select()
* except that it atomically changes the sigprocmask() during the op.
*
* @raise ECANCELED if thread was cancelled in masked mode
* @raise EINTR if signal was delivered
* @cancellationpoint
* @asyncsignalsafe
* @threadsafe
* @norestart
*/
int pselect(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
const struct timespec *timeout, const sigset_t *sigmask) {
int rc;
struct timeval tv, *tvp;
struct timespec ts, *tsp;
struct {
const sigset_t *s;
size_t n;
} ss;
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))) ||
(timeout && !__asan_is_valid(timeout, sizeof(*timeout))) ||
(sigmask && !__asan_is_valid(sigmask, sizeof(*sigmask))))) {
rc = efault();
} else if (IsLinux()) {
if (timeout) {
ts = *timeout;
tsp = &ts;
} else {
tsp = 0;
}
ss.s = sigmask;
ss.n = 8;
rc = sys_pselect(nfds, readfds, writefds, exceptfds, tsp, &ss);
} else if (!IsWindows()) {
rc = sys_pselect(nfds, readfds, writefds, exceptfds,
(struct timespec *)timeout, sigmask);
} else {
if (timeout) {
tv.tv_sec = timeout->tv_sec;
tv.tv_usec = timeout->tv_nsec / 1000;
tvp = &tv;
} else {
tvp = 0;
}
rc = sys_select_nt(nfds, readfds, writefds, exceptfds, tvp, sigmask);
}
END_CANCELLATION_POINT;
POLLTRACE("pselect(%d, %p, %p, %p, %s, %s) → %d% m", nfds, readfds, writefds,
exceptfds, DescribeTimespec(0, timeout), DescribeSigset(0, sigmask),
rc);
return rc;
}