89 lines · cpp
1//===-- Linux implementation of the pthread_create 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-exception6//7//===----------------------------------------------------------------------===//8 9#include "pthread_create.h"10 11#include "pthread_attr_destroy.h"12#include "pthread_attr_init.h"13 14#include "pthread_attr_getdetachstate.h"15#include "pthread_attr_getguardsize.h"16#include "pthread_attr_getstack.h"17 18#include "src/__support/common.h"19#include "src/__support/libc_errno.h"20#include "src/__support/macros/config.h"21#include "src/__support/macros/optimization.h"22#include "src/__support/threads/thread.h"23 24#include <pthread.h> // For pthread_* type definitions.25 26namespace LIBC_NAMESPACE_DECL {27 28static_assert(sizeof(pthread_t) == sizeof(LIBC_NAMESPACE::Thread),29 "Mismatch between pthread_t and internal Thread.");30 31LLVM_LIBC_FUNCTION(int, pthread_create,32 (pthread_t *__restrict th,33 const pthread_attr_t *__restrict attr,34 __pthread_start_t func, void *arg)) {35 pthread_attr_t default_attr;36 if (attr == nullptr) {37 // We failed to initialize attributes (should be impossible)38 if (LIBC_UNLIKELY(LIBC_NAMESPACE::pthread_attr_init(&default_attr) != 0))39 return EINVAL;40 41 attr = &default_attr;42 }43 44 void *stack;45 size_t stacksize, guardsize;46 int detachstate;47 48 // As of writing this all the `pthread_attr_get*` functions always succeed.49 if (LIBC_UNLIKELY(50 LIBC_NAMESPACE::pthread_attr_getstack(attr, &stack, &stacksize) != 0))51 return EINVAL;52 53 if (LIBC_UNLIKELY(54 LIBC_NAMESPACE::pthread_attr_getguardsize(attr, &guardsize) != 0))55 return EINVAL;56 57 if (LIBC_UNLIKELY(58 LIBC_NAMESPACE::pthread_attr_getdetachstate(attr, &detachstate) != 0))59 return EINVAL;60 61 if (attr == &default_attr)62 // Should we fail here? Its non-issue as the moment as pthread_attr_destroy63 // can only succeed.64 if (LIBC_UNLIKELY(LIBC_NAMESPACE::pthread_attr_destroy(&default_attr) != 0))65 return EINVAL;66 67 if (stacksize && stacksize < PTHREAD_STACK_MIN)68 return EINVAL;69 70 if (guardsize % EXEC_PAGESIZE != 0)71 return EINVAL;72 73 if (detachstate != PTHREAD_CREATE_DETACHED &&74 detachstate != PTHREAD_CREATE_JOINABLE)75 return EINVAL;76 77 // Thread::run will check validity of the `stack` argument (stack alignment is78 // universal, not sure a pthread requirement).79 80 auto *thread = reinterpret_cast<LIBC_NAMESPACE::Thread *>(th);81 int result = thread->run(func, arg, stack, stacksize, guardsize,82 detachstate == PTHREAD_CREATE_DETACHED);83 if (result != 0 && result != EPERM && result != EINVAL)84 return EAGAIN;85 return result;86}87 88} // namespace LIBC_NAMESPACE_DECL89