xref: /aosp_15_r20/external/llvm-libc/src/pthread/pthread_rwlock_clockwrlock.cpp (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1 //===-- Implementation of the Rwlock's clockwrlock 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_clockwrlock.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 #include "src/__support/time/linux/abs_timeout.h"
16 
17 #include <pthread.h>
18 
19 namespace LIBC_NAMESPACE_DECL {
20 
21 static_assert(
22     sizeof(RwLock) == sizeof(pthread_rwlock_t) &&
23         alignof(RwLock) == alignof(pthread_rwlock_t),
24     "The public pthread_rwlock_t type must be of the same size and alignment "
25     "as the internal rwlock type.");
26 
27 LLVM_LIBC_FUNCTION(int, pthread_rwlock_clockwrlock,
28                    (pthread_rwlock_t * rwlock, clockid_t clockid,
29                     const timespec *abstime)) {
30   if (!rwlock)
31     return EINVAL;
32   if (clockid != CLOCK_MONOTONIC && clockid != CLOCK_REALTIME)
33     return EINVAL;
34   bool is_realtime = (clockid == CLOCK_REALTIME);
35   RwLock *rw = reinterpret_cast<RwLock *>(rwlock);
36   LIBC_ASSERT(abstime && "clockwrlock called with a null timeout");
37   auto timeout = internal::AbsTimeout::from_timespec(
38       *abstime, /*is_realtime=*/is_realtime);
39   if (LIBC_LIKELY(timeout.has_value()))
40     return static_cast<int>(rw->write_lock(timeout.value()));
41 
42   switch (timeout.error()) {
43   case internal::AbsTimeout::Error::Invalid:
44     return EINVAL;
45   case internal::AbsTimeout::Error::BeforeEpoch:
46     return ETIMEDOUT;
47   }
48   __builtin_unreachable();
49 }
50 
51 } // namespace LIBC_NAMESPACE_DECL
52