1 //===-- Implementation of the Rwlock's clockrdlock 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_clockrdlock.h" 10 11 #include "hdr/errno_macros.h" 12 #include "src/__support/common.h" 13 #include "src/__support/macros/config.h" 14 #include "src/__support/threads/linux/rwlock.h" 15 16 #include <pthread.h> 17 18 namespace LIBC_NAMESPACE_DECL { 19 20 static_assert( 21 sizeof(RwLock) == sizeof(pthread_rwlock_t) && 22 alignof(RwLock) == alignof(pthread_rwlock_t), 23 "The public pthread_rwlock_t type must be of the same size and alignment " 24 "as the internal rwlock type."); 25 26 LLVM_LIBC_FUNCTION(int, pthread_rwlock_clockrdlock, 27 (pthread_rwlock_t * rwlock, clockid_t clockid, 28 const timespec *abstime)) { 29 if (!rwlock) 30 return EINVAL; 31 if (clockid != CLOCK_MONOTONIC && clockid != CLOCK_REALTIME) 32 return EINVAL; 33 bool is_realtime = (clockid == CLOCK_REALTIME); 34 RwLock *rw = reinterpret_cast<RwLock *>(rwlock); 35 LIBC_ASSERT(abstime && "clockrdlock called with a null timeout"); 36 auto timeout = internal::AbsTimeout::from_timespec( 37 *abstime, /*is_realtime=*/is_realtime); 38 if (LIBC_LIKELY(timeout.has_value())) 39 return static_cast<int>(rw->read_lock(timeout.value())); 40 41 switch (timeout.error()) { 42 case internal::AbsTimeout::Error::Invalid: 43 return EINVAL; 44 case internal::AbsTimeout::Error::BeforeEpoch: 45 return ETIMEDOUT; 46 } 47 __builtin_unreachable(); 48 } 49 50 } // namespace LIBC_NAMESPACE_DECL 51