glibc/nptl/cleanup_defer.c

/* Copyright (C) 2002-2024 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 <stdlib.h>
#include "pthreadP.h"
#include <shlib-compat.h>

void
__cleanup_fct_attribute
___pthread_register_cancel_defer (__pthread_unwind_buf_t *buf)
{
  struct pthread_unwind_buf *ibuf = (struct pthread_unwind_buf *) buf;
  struct pthread *self = THREAD_SELF;

  /* Store old info.  */
  ibuf->priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
  ibuf->priv.data.cleanup = THREAD_GETMEM (self, cleanup);

  int cancelhandling = atomic_load_relaxed (&self->cancelhandling);
  if (__glibc_unlikely (cancelhandling & CANCELTYPE_BITMASK))
    {
      int newval;
      do
	{
	  newval = cancelhandling & ~CANCELTYPE_BITMASK;
	}
      while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling,
						    &cancelhandling,
						    newval));
    }

  ibuf->priv.data.canceltype = (cancelhandling & CANCELTYPE_BITMASK
				? PTHREAD_CANCEL_ASYNCHRONOUS
				: PTHREAD_CANCEL_DEFERRED);

  /* Store the new cleanup handler info.  */
  THREAD_SETMEM (self, cleanup_jmp_buf, (struct pthread_unwind_buf *) buf);
}
versioned_symbol (libc, ___pthread_register_cancel_defer,
		  __pthread_register_cancel_defer, GLIBC_2_34);

#if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_3_3, GLIBC_2_34)
compat_symbol (libpthread, ___pthread_register_cancel_defer,
	       __pthread_register_cancel_defer, GLIBC_2_3_3);
#endif

void
__cleanup_fct_attribute
___pthread_unregister_cancel_restore (__pthread_unwind_buf_t *buf)
{
  struct pthread *self = THREAD_SELF;
  struct pthread_unwind_buf *ibuf = (struct pthread_unwind_buf *) buf;

  THREAD_SETMEM (self, cleanup_jmp_buf, ibuf->priv.data.prev);

  if (ibuf->priv.data.canceltype == PTHREAD_CANCEL_DEFERRED)
    return;

  int cancelhandling = atomic_load_relaxed (&self->cancelhandling);
  if ((cancelhandling & CANCELTYPE_BITMASK) == 0)
    {
      int newval;
      do
	{
	  newval = cancelhandling | CANCELTYPE_BITMASK;
	}
      while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling,
						    &cancelhandling, newval));

      if (cancel_enabled_and_canceled (cancelhandling))
	__do_cancel (PTHREAD_CANCELED);
    }
}
versioned_symbol (libc, ___pthread_unregister_cancel_restore,
		  __pthread_unregister_cancel_restore, GLIBC_2_34);

#if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_3_3, GLIBC_2_34)
compat_symbol (libpthread, ___pthread_unregister_cancel_restore,
	       __pthread_unregister_cancel_restore, GLIBC_2_3_3);
#endif