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-exception 6 // 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/macros/config.h" 20 #include "src/__support/macros/optimization.h" 21 #include "src/__support/threads/thread.h" 22 #include "src/errno/libc_errno.h" 23 24 #include <pthread.h> // For pthread_* type definitions. 25 26 namespace LIBC_NAMESPACE_DECL { 27 28 static_assert(sizeof(pthread_t) == sizeof(LIBC_NAMESPACE::Thread), 29 "Mismatch between pthread_t and internal Thread."); 30 31 LLVM_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_destroy 63 // 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 is 78 // 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_DECL 89