cosmopolitan/libc/calls/tcflush.c
Justine Tunney f7ff77d865
Make fixes and improvements
- Invent iso8601us() for faster timestamps
- Improve --strace descriptions of sigset_t
- Rebuild the Landlock Make bootstrap binary
- Introduce MODE=sysv for non-Windows builds
- Permit OFD fcntl() locks under pledge(flock)
- redbean can now protect your kernel from ddos
- Have vfork() fallback to sys_fork() not fork()
- Change kmalloc() to not die when out of memory
- Improve documentation for some termios functions
- Rewrite putenv() and friends to conform to POSIX
- Fix linenoise + strace verbosity issue on Windows
- Fix regressions in our ability to show backtraces
- Change redbean SetHeader() to no-op if value is nil
- Improve fcntl() so SQLite locks work in non-WAL mode
- Remove some unnecessary work during fork() on Windows
- Create redbean-based SSL reverse proxy for IPv4 TurfWar
- Fix ape/apeinstall.sh warning when using non-bash shells
- Add ProgramTrustedIp(), and IsTrustedIp() APIs to redbean
- Support $PWD, $UID, $GID, and $EUID in command interpreter
- Introduce experimental JTqFpD APE prefix for non-Windows builds
- Invent blackhole daemon for firewalling IP addresses via UNIX named socket
- Add ProgramTokenBucket(), AcquireToken(), and CountTokens() APIs to redbean
2022-10-19 07:19:19 -07:00

85 lines
3.8 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 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/internal.h"
#include "libc/calls/syscall-nt.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/fmt/itoa.h"
#include "libc/intrin/strace.internal.h"
#include "libc/mem/alloca.h"
#include "libc/nt/comms.h"
#include "libc/sysv/consts/termios.h"
#include "libc/sysv/errfuns.h"
#define kNtPurgeTxclear 4
#define kNtPurgeRxclear 8
static const char *DescribeFlush(char buf[12], int action) {
if (action == TCIFLUSH) return "TCIFLUSH";
if (action == TCOFLUSH) return "TCOFLUSH";
if (action == TCIOFLUSH) return "TCIOFLUSH";
FormatInt32(buf, action);
return buf;
}
static dontinline textwindows int sys_tcflush_nt(int fd, int queue) {
bool32 ok;
int64_t h;
if (!__isfdopen(fd)) return ebadf();
ok = true;
h = g_fds.p[fd].handle;
if (queue == TCIFLUSH || queue == TCIOFLUSH) {
ok &= !!PurgeComm(h, kNtPurgeRxclear);
}
if (queue == TCOFLUSH || queue == TCIOFLUSH) {
ok &= !!PurgeComm(h, kNtPurgeTxclear);
}
return ok ? 0 : __winerr();
}
/**
* Discards queued data on teletypewriter.
*
* @param queue may be one of:
* - `TCIFLUSH` flushes data received but not read
* - `TCOFLUSH` flushes data written but not transmitted
* - `TCIOFLUSH` does both `TCOFLUSH` and `TCIFLUSH`
* @return 0 on success, or -1 w/ errno
* @raise EINVAL if `action` is invalid
* @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 ENOSYS on bare metal
* @asyncsignalsafe
*/
int tcflush(int fd, int queue) {
int rc;
if (IsMetal()) {
rc = enosys();
} else if (!IsWindows()) {
rc = sys_ioctl(fd, TCFLSH, queue);
} else {
rc = sys_tcflush_nt(fd, queue);
}
STRACE("tcflush(%d, %s) → %d% m", fd, DescribeFlush(alloca(12), queue), rc);
return rc;
}