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Diffstat (limited to 'nptl/lowlevellock.c')
| -rw-r--r-- | nptl/lowlevellock.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/nptl/lowlevellock.c b/nptl/lowlevellock.c new file mode 100644 index 0000000000..e198af7e8d --- /dev/null +++ b/nptl/lowlevellock.c @@ -0,0 +1,124 @@ +/* low level locking for pthread library. Generic futex-using version. + Copyright (C) 2003-2014 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003. + + 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/>. */ + +#include <errno.h> +#include <sysdep.h> +#include <lowlevellock.h> +#include <sys/time.h> +#include <atomic.h> + +void +__lll_lock_wait_private (int *futex) +{ + if (*futex == 2) + lll_futex_wait (futex, 2, LLL_PRIVATE); + + while (atomic_exchange_acq (futex, 2) != 0) + lll_futex_wait (futex, 2, LLL_PRIVATE); +} + + +/* These functions don't get included in libc.so */ +#ifdef IS_IN_libpthread +void +__lll_lock_wait (int *futex, int private) +{ + if (*futex == 2) + lll_futex_wait (futex, 2, private); + + while (atomic_exchange_acq (futex, 2) != 0) + lll_futex_wait (futex, 2, private); +} + + +int +__lll_timedlock_wait (int *futex, const struct timespec *abstime, int private) +{ + /* Reject invalid timeouts. */ + if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) + return EINVAL; + + /* Try locking. */ + while (atomic_exchange_acq (futex, 2) != 0) + { + struct timeval tv; + + /* Get the current time. */ + (void) __gettimeofday (&tv, NULL); + + /* Compute relative timeout. */ + struct timespec rt; + rt.tv_sec = abstime->tv_sec - tv.tv_sec; + rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000; + if (rt.tv_nsec < 0) + { + rt.tv_nsec += 1000000000; + --rt.tv_sec; + } + + if (rt.tv_sec < 0) + return ETIMEDOUT; + + /* Wait. */ + lll_futex_timed_wait (futex, 2, &rt, private); + } + + return 0; +} + + +int +__lll_timedwait_tid (int *tidp, const struct timespec *abstime) +{ + int tid; + + if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) + return EINVAL; + + /* Repeat until thread terminated. */ + while ((tid = *tidp) != 0) + { + struct timeval tv; + struct timespec rt; + + /* Get the current time. */ + (void) __gettimeofday (&tv, NULL); + + /* Compute relative timeout. */ + rt.tv_sec = abstime->tv_sec - tv.tv_sec; + rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000; + if (rt.tv_nsec < 0) + { + rt.tv_nsec += 1000000000; + --rt.tv_sec; + } + + /* Already timed out? */ + if (rt.tv_sec < 0) + return ETIMEDOUT; + + /* Wait until thread terminates. The kernel so far does not use + the private futex operations for this. */ + if (lll_futex_timed_wait (tidp, tid, &rt, LLL_SHARED) == -ETIMEDOUT) + return ETIMEDOUT; + } + + return 0; +} +#endif |