cosmopolitan/libc/calls/tcdrain.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

63 lines
3.1 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 2021 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/internal.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/calls/syscall_support-nt.internal.h"
#include "libc/calls/termios.h"
#include "libc/dce.h"
#include "libc/intrin/strace.internal.h"
#include "libc/nt/files.h"
#include "libc/sysv/errfuns.h"
static textwindows int sys_tcdrain_nt(int fd) {
if (!__isfdopen(fd)) return ebadf();
if (_check_interrupts(false, g_fds.p)) return -1;
if (!FlushFileBuffers(g_fds.p[fd].handle)) return __winerr();
return 0;
}
/**
* Waits until all written output is transmitted.
*
* @param fd is file descriptor of tty
* @raise EBADF if `fd` isn't an open file descriptor
* @raise ENOTTY if `fd` is open but not a teletypewriter
* @raise EIO if process group of writer is orphoned, calling thread is
* not blocking `SIGTTOU`, and process isn't ignoring `SIGTTOU`
* @raise ECANCELED if thread was cancelled in masked mode
* @raise EINTR if signal was delivered
* @raise ENOSYS on bare metal
* @cancellationpoint
* @asyncsignalsafe
*/
int tcdrain(int fd) {
int rc;
BEGIN_CANCELLATION_POINT;
if (IsMetal()) {
rc = enosys();
} else if (!IsWindows()) {
rc = sys_ioctl_cp(fd, TCSBRK, (void *)(intptr_t)1);
} else {
rc = sys_tcdrain_nt(fd);
}
END_CANCELLATION_POINT;
STRACE("tcdrain(%d) → %d% m", fd, rc);
return rc;
}