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/* futex operations for glibc-internal use. NaCl version.
Copyright (C) 2014-2016 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
<http://www.gnu.org/licenses/>. */
#ifndef FUTEX_INTERNAL_H
#define FUTEX_INTERNAL_H
#include <sysdeps/nptl/futex-internal.h>
#include <errno.h>
#include <lowlevellock-futex.h>
#include <nacl-interfaces.h>
#include <nptl/pthreadP.h>
/* See sysdeps/nptl/futex-internal.h for documentation; this file only
contains NaCl-specific comments.
There is no support yet for shared futexes nor for exact relative
timeouts. */
/* See sysdeps/nptl/futex-internal.h for constraints on the value of the
FUTEX_PRIVATE and FUTEX_SHARED constants.
Shared futexes are not yet supported, and we never allow clients to
actually request shared futexes. Therefore, we do not need a different
value. */
#undef FUTEX_SHARED
#define FUTEX_SHARED FUTEX_PRIVATE
/* FUTEX_SHARED is not yet supported. */
static __always_inline int
futex_supports_pshared (int pshared)
{
if (__glibc_likely (pshared == PTHREAD_PROCESS_PRIVATE))
return 0;
else if (pshared == PTHREAD_PROCESS_SHARED)
return ENOTSUP;
else
return EINVAL;
}
/* Relative timeouts are only emulated via absolute timeouts using the
system clock. */
static __always_inline bool
futex_supports_exact_relative_timeouts (void)
{
return false;
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_wait (unsigned int *futex_word, unsigned int expected, int private)
{
int err = lll_futex_timed_wait (futex_word, expected, NULL, private);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
return -err;
case -ETIMEDOUT: /* Cannot have happened as we provided no timeout. */
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_wait_cancelable (unsigned int *futex_word, unsigned int expected,
int private)
{
int oldtype;
oldtype = __pthread_enable_asynccancel ();
int err = lll_futex_timed_wait (futex_word, expected, NULL, private);
__pthread_disable_asynccancel (oldtype);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
return -err;
case -ETIMEDOUT: /* Cannot have happened as we provided no timeout. */
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_reltimed_wait (unsigned int *futex_word, unsigned int expected,
const struct timespec *reltime, int private)
{
int err = lll_futex_timed_wait (futex_word, expected, reltime, private);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
case -ETIMEDOUT:
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_reltimed_wait_cancelable (unsigned int *futex_word,
unsigned int expected,
const struct timespec *reltime, int private)
{
int oldtype;
oldtype = __pthread_enable_asynccancel ();
int err = lll_futex_timed_wait (futex_word, expected, reltime, private);
__pthread_disable_asynccancel (oldtype);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
case -ETIMEDOUT:
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_abstimed_wait (unsigned int *futex_word, unsigned int expected,
const struct timespec *abstime, int private)
{
int err = __nacl_irt_futex.futex_wait_abs ((volatile int *) futex_word,
expected, abstime);
switch (err)
{
case 0:
case EAGAIN:
case EINTR:
case ETIMEDOUT:
return err;
case EFAULT: /* Must have been caused by a glibc or application bug. */
case EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_abstimed_wait_cancelable (unsigned int *futex_word,
unsigned int expected,
const struct timespec *abstime, int private)
{
int oldtype;
oldtype = __pthread_enable_asynccancel ();
int err = __nacl_irt_futex.futex_wait_abs ((volatile int *) futex_word,
expected, abstime);
__pthread_disable_asynccancel (oldtype);
switch (err)
{
case 0:
case EAGAIN:
case EINTR:
case ETIMEDOUT:
return err;
case EFAULT: /* Must have been caused by a glibc or application bug. */
case EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline void
futex_wake (unsigned int *futex_word, int processes_to_wake, int private)
{
int res = lll_futex_wake (futex_word, processes_to_wake, private);
/* No error. Ignore the number of woken processes. */
if (res >= 0)
return;
switch (res)
{
case -EFAULT: /* Could have happened due to memory reuse. */
case -EINVAL: /* Could be either due to incorrect alignment (a bug in
glibc or in the application) or due to memory being
reused for a PI futex. We cannot distinguish between the
two causes, and one of them is correct use, so we do not
act in this case. */
return;
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
#endif /* futex-internal.h */
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