cosmopolitan/libc/calls/nanosleep-xnu.c
Justine Tunney 3f0bcdc3ef
Improve cancellations, randomness, and time
- Exhaustively document cancellation points
- Rename SIGCANCEL to SIGTHR just like BSDs
- Further improve POSIX thread cancellations
- Ensure asynchronous cancellations work correctly
- Elevate the quality of getrandom() and getentropy()
- Make futexes cancel correctly on OpenBSD 6.x and 7.x
- Add reboot.com and shutdown.com to examples directory
- Remove underscore prefix from awesome timespec_*() APIs
- Create assertions that help verify our cancellation points
- Remove bad timespec APIs (cmp generalizes eq/ne/gt/gte/lt/lte)
2022-11-05 23:45:32 -07:00

52 lines
2.8 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/calls/struct/timespec.h"
#include "libc/calls/struct/timespec.internal.h"
#include "libc/calls/struct/timeval.h"
#include "libc/calls/struct/timeval.internal.h"
#include "libc/errno.h"
#include "libc/sock/internal.h"
// nanosleep() on xnu: a bloodbath of a polyfill
// consider using clock_nanosleep(TIMER_ABSTIME)
int sys_nanosleep_xnu(const struct timespec *req, struct timespec *rem) {
int rc;
struct timeval wt, t1, t2, td;
if (rem) sys_gettimeofday_xnu(&t1, 0, 0);
wt = timespec_totimeval(*req); // rounds up
rc = sys_select(0, 0, 0, 0, &wt);
if (rem) {
if (!rc) {
rem->tv_sec = 0;
rem->tv_nsec = 0;
} else if (rc == -1 && errno == EINTR) {
// xnu select() doesn't modify timeout
// so we need, yet another system call
sys_gettimeofday_xnu(&t2, 0, 0);
td = timeval_sub(t2, t1);
if (timeval_cmp(td, wt) >= 0) {
rem->tv_sec = 0;
rem->tv_nsec = 0;
} else {
*rem = timeval_totimespec(timeval_sub(wt, td));
}
}
}
return rc;
}