Permalink
Cannot retrieve contributors at this time
Name already in use
A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
glibc/sysdeps/unix/sysv/linux/futex-internal.h
Go to fileThis commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
251 lines (227 sloc)
8.28 KB
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| /* futex operations for glibc-internal use. Linux 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 <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 */ |