mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-02 09:40:13 +00:00
252 lines
8.3 KiB
C
252 lines
8.3 KiB
C
|
/* futex operations for glibc-internal use. Linux version.
|
||
|
|
Copyright (C) 2014-2015 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 <nptl/pthreadP.h>
|
||
|
|
|
||
|
|
/* See sysdeps/nptl/futex-internal.h for documentation; this file only
|
||
|
|
contains Linux-specific comments.
|
||
|
|
|
||
|
|
The Linux kernel treats provides absolute timeouts based on the
|
||
|
|
CLOCK_REALTIME clock and relative timeouts measured against the
|
||
|
|
CLOCK_MONOTONIC clock.
|
||
|
|
|
||
|
|
We expect a Linux kernel version of 2.6.22 or more recent (since this
|
||
|
|
version, EINTR is not returned on spurious wake-ups anymore). */
|
||
|
|
|
||
|
|
/* FUTEX_SHARED is always supported by the Linux kernel. */
|
||
|
|
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 0;
|
||
|
|
else
|
||
|
|
return EINVAL;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* The Linux kernel supports relative timeouts measured against the
|
||
|
|
CLOCK_MONOTONIC clock. */
|
||
|
|
static __always_inline bool
|
||
|
|
futex_supports_exact_relative_timeouts (void)
|
||
|
|
{
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* 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)
|
||
|
|
{
|
||
|
|
/* Work around the fact that the kernel rejects negative timeout values
|
||
|
|
despite them being valid. */
|
||
|
|
if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0)))
|
||
|
|
return ETIMEDOUT;
|
||
|
|
int err = lll_futex_timed_wait_bitset (futex_word, expected, abstime,
|
||
|
|
FUTEX_CLOCK_REALTIME, 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_abstimed_wait_cancelable (unsigned int *futex_word,
|
||
|
|
unsigned int expected,
|
||
|
|
const struct timespec *abstime, int private)
|
||
|
|
{
|
||
|
|
/* Work around the fact that the kernel rejects negative timeout values
|
||
|
|
despite them being valid. */
|
||
|
|
if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0)))
|
||
|
|
return ETIMEDOUT;
|
||
|
|
int oldtype;
|
||
|
|
oldtype = __pthread_enable_asynccancel ();
|
||
|
|
int err = lll_futex_timed_wait_bitset (futex_word, expected, abstime,
|
||
|
|
FUTEX_CLOCK_REALTIME, 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 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 */
|