cosmopolitan/libc/intrin/pthread_setcancelstate.c
Jōshin e16a7d8f3b
flip et / noet in modelines
`et` means `expandtab`.

```sh
rg 'vi: .* :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\)  :vi/vi: \1 xoet\2:vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2  :vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/'
```
2023-12-07 22:17:11 -05:00

101 lines
4.3 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et 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/dce.h"
#include "libc/errno.h"
#include "libc/intrin/describeflags.internal.h"
#include "libc/intrin/strace.internal.h"
#include "libc/thread/posixthread.internal.h"
#include "libc/thread/thread.h"
#include "libc/thread/tls.h"
/**
* Sets cancelability state.
*
* This function may be used to temporarily disable cancelation for the
* calling thread, which is necessary in cases when a @cancelationpoint
* function is invoked from an @asyncsignalsafe function.
*
* Cosmopolitan Libc supports the Musl Libc `PTHREAD_CANCEL_MASKED`
* non-POSIX extension. Any thread may use this setting, in which case
* the thread won't be abruptly destroyed upon a cancelation and have
* its stack unwound; instead, the thread will encounter an `ECANCELED`
* errno the next time it calls a cancelation point.
*
* @param state may be one of:
* - `PTHREAD_CANCEL_ENABLE` (default)
* - `PTHREAD_CANCEL_DISABLE`
* - `PTHREAD_CANCEL_MASKED`
* @param oldstate optionally receives old value
* @return 0 on success, or errno on error
* @raise EINVAL if `state` has bad value
* @asyncsignalsafe
*/
errno_t pthread_setcancelstate(int state, int *oldstate) {
errno_t err;
struct PosixThread *pt;
if (__tls_enabled && (pt = _pthread_self())) {
switch (state) {
case PTHREAD_CANCEL_ENABLE:
case PTHREAD_CANCEL_DISABLE:
case PTHREAD_CANCEL_MASKED:
if (oldstate) {
if (pt->pt_flags & PT_NOCANCEL) {
*oldstate = PTHREAD_CANCEL_DISABLE;
} else if (pt->pt_flags & PT_MASKED) {
*oldstate = PTHREAD_CANCEL_MASKED;
} else {
*oldstate = PTHREAD_CANCEL_ENABLE;
}
}
pt->pt_flags &= ~(PT_NOCANCEL | PT_MASKED);
if (state == PTHREAD_CANCEL_MASKED) {
pt->pt_flags |= PT_MASKED;
} else if (state == PTHREAD_CANCEL_DISABLE) {
pt->pt_flags |= PT_NOCANCEL;
}
err = 0;
break;
default:
err = EINVAL;
break;
}
} else {
if (oldstate) {
*oldstate = 0;
}
err = 0;
}
#if IsModeDbg()
STRACE("pthread_setcancelstate(%s, [%s]) → %s",
DescribeCancelState(0, &state), DescribeCancelState(err, oldstate),
DescribeErrno(err));
#endif
return err;
}
int _pthread_block_cancelation(void) {
int oldstate;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldstate);
return oldstate;
}
void _pthread_allow_cancelation(int oldstate) {
pthread_setcancelstate(oldstate, 0);
}