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/* Copyright (C) 2002-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <setjmp.h>
#include <stdlib.h>
#include "pthreadP.h"
/* Called by the INTERNAL_SYSCALL_CANCEL macro, check for cancellation and
returns the syscall value or its negative error code. */
long int
__internal_syscall_cancel (__syscall_arg_t a1, __syscall_arg_t a2,
__syscall_arg_t a3, __syscall_arg_t a4,
__syscall_arg_t a5, __syscall_arg_t a6,
__syscall_arg_t nr)
{
long int result;
struct pthread *pd = THREAD_SELF;
/* If cancellation is not enabled, call the syscall directly and also
for thread terminatation to avoid call __syscall_do_cancel while
executing cleanup handlers. */
int ch = atomic_load_relaxed (&pd->cancelhandling);
if (SINGLE_THREAD_P || !cancel_enabled (ch) || cancel_exiting (ch))
{
result = INTERNAL_SYSCALL_NCS_CALL (nr, a1, a2, a3, a4, a5, a6);
if (INTERNAL_SYSCALL_ERROR_P (result))
return -INTERNAL_SYSCALL_ERRNO (result);
return result;
}
/* Call the arch-specific entry points that contains the globals markers
to be checked by SIGCANCEL handler. */
result = __syscall_cancel_arch (&pd->cancelhandling, nr, a1, a2, a3, a4, a5,
a6);
/* If the cancellable syscall was interrupted by SIGCANCEL and it has not
side-effect, cancel the thread if cancellation is enabled. */
ch = atomic_load_relaxed (&pd->cancelhandling);
if (result == -EINTR && cancel_enabled_and_canceled (ch))
__syscall_do_cancel ();
return result;
}
/* Called by the SYSCALL_CANCEL macro, check for cancellation and return the
syscall expected success value (usually 0) or, in case of failure, -1 and
sets errno to syscall return value. */
long int
__syscall_cancel (__syscall_arg_t a1, __syscall_arg_t a2,
__syscall_arg_t a3, __syscall_arg_t a4,
__syscall_arg_t a5, __syscall_arg_t a6,
__syscall_arg_t nr)
{
int r = __internal_syscall_cancel (a1, a2, a3, a4, a5, a6, nr);
return __glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (r))
? SYSCALL_ERROR_LABEL (INTERNAL_SYSCALL_ERRNO (r))
: r;
}
/* Called by __syscall_cancel_arch or function above start the thread
cancellation. */
_Noreturn void
__syscall_do_cancel (void)
{
struct pthread *self = THREAD_SELF;
/* Disable thread cancellation to avoid cancellable entrypoints to call
__syscall_do_cancel recursively. */
int oldval = atomic_load_relaxed (&self->cancelhandling);
while (1)
{
int newval = oldval | CANCELSTATE_BITMASK;
if (oldval == newval)
break;
if (atomic_compare_exchange_weak_acquire (&self->cancelhandling,
&oldval, newval))
break;
}
__do_cancel (PTHREAD_CANCELED);
}
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