1 //===-- Implementation of the Rwlock's timedrdlock function ---------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "src/pthread/pthread_rwlock_timedrdlock.h" 10 #include "src/__support/common.h" 11 #include "src/__support/libc_assert.h" 12 #include "src/__support/macros/config.h" 13 #include "src/__support/macros/optimization.h" 14 #include "src/__support/threads/linux/rwlock.h" 15 #include "src/__support/time/linux/abs_timeout.h" 16 #include "src/errno/libc_errno.h" 17 18 #include <pthread.h> 19 20 namespace LIBC_NAMESPACE_DECL { 21 22 static_assert( 23 sizeof(RwLock) == sizeof(pthread_rwlock_t) && 24 alignof(RwLock) == alignof(pthread_rwlock_t), 25 "The public pthread_rwlock_t type must be of the same size and alignment " 26 "as the internal rwlock type."); 27 28 LLVM_LIBC_FUNCTION(int, pthread_rwlock_timedrdlock, 29 (pthread_rwlock_t * rwlock, 30 const struct timespec *abstime)) { 31 if (!rwlock) 32 return EINVAL; 33 RwLock *rw = reinterpret_cast<RwLock *>(rwlock); 34 LIBC_ASSERT(abstime && "timedrdlock called with a null timeout"); 35 auto timeout = 36 internal::AbsTimeout::from_timespec(*abstime, /*is_realtime=*/true); 37 if (LIBC_LIKELY(timeout.has_value())) 38 return static_cast<int>(rw->read_lock(timeout.value())); 39 40 switch (timeout.error()) { 41 case internal::AbsTimeout::Error::Invalid: 42 return EINVAL; 43 case internal::AbsTimeout::Error::BeforeEpoch: 44 return ETIMEDOUT; 45 } 46 __builtin_unreachable(); 47 } 48 49 } // namespace LIBC_NAMESPACE_DECL 50