69 lines
2.0 KiB
C++
69 lines
2.0 KiB
C++
//===-- Linux implementation of the pthread_rwlock_init function ----------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "src/pthread/pthread_rwlock_init.h"
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#include "src/__support/CPP/new.h"
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#include "src/__support/common.h"
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#include "src/__support/libc_assert.h"
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#include "src/__support/macros/config.h"
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#include "src/__support/threads/linux/rwlock.h"
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#include <errno.h>
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#include <pthread.h>
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namespace LIBC_NAMESPACE_DECL {
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static_assert(
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sizeof(RwLock) == sizeof(pthread_rwlock_t) &&
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alignof(RwLock) == alignof(pthread_rwlock_t),
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"The public pthread_rwlock_t type must be of the same size and alignment "
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"as the internal rwlock type.");
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LLVM_LIBC_FUNCTION(int, pthread_rwlock_init,
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(pthread_rwlock_t * rwlock,
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const pthread_rwlockattr_t *__restrict attr)) {
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pthread_rwlockattr_t rwlockattr{
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/*pshared=*/PTHREAD_PROCESS_PRIVATE,
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/*pref*/ PTHREAD_RWLOCK_PREFER_READER_NP,
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};
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// POSIX does not specify this check, so we add an assertion to catch it.
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LIBC_ASSERT(rwlock && "rwlock is null");
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if (attr)
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rwlockattr = *attr;
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// PTHREAD_RWLOCK_PREFER_WRITER_NP is not supported.
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rwlock::Role preference;
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switch (rwlockattr.pref) {
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case PTHREAD_RWLOCK_PREFER_READER_NP:
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preference = rwlock::Role::Reader;
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break;
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case PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP:
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preference = rwlock::Role::Writer;
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break;
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default:
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return EINVAL;
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}
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bool is_pshared;
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switch (rwlockattr.pshared) {
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case PTHREAD_PROCESS_PRIVATE:
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is_pshared = false;
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break;
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case PTHREAD_PROCESS_SHARED:
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is_pshared = true;
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break;
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default:
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return EINVAL;
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}
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new (rwlock) RwLock(preference, is_pshared);
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return 0;
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}
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} // namespace LIBC_NAMESPACE_DECL
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