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/optimization.h" 20 #include "src/__support/threads/thread.h" 21 22 #include <errno.h> 23 #include <pthread.h> // For pthread_* type definitions. 24 25 namespace LIBC_NAMESPACE { 26 27 static_assert(sizeof(pthread_t) == sizeof(LIBC_NAMESPACE::Thread), 28 "Mismatch between pthread_t and internal Thread."); 29 30 LLVM_LIBC_FUNCTION(int, pthread_create, 31 (pthread_t *__restrict th, 32 const pthread_attr_t *__restrict attr, 33 __pthread_start_t func, void *arg)) { 34 pthread_attr_t default_attr; 35 if (attr == nullptr) { 36 // We failed to initialize attributes (should be impossible) 37 if (LIBC_UNLIKELY(LIBC_NAMESPACE::pthread_attr_init(&default_attr) != 0)) 38 return EINVAL; 39 40 attr = &default_attr; 41 } 42 43 void *stack; 44 size_t stacksize, guardsize; 45 int detachstate; 46 47 // As of writing this all the `pthread_attr_get*` functions always succeed. 48 if (LIBC_UNLIKELY( 49 LIBC_NAMESPACE::pthread_attr_getstack(attr, &stack, &stacksize) != 0)) 50 return EINVAL; 51 52 if (LIBC_UNLIKELY( 53 LIBC_NAMESPACE::pthread_attr_getguardsize(attr, &guardsize) != 0)) 54 return EINVAL; 55 56 if (LIBC_UNLIKELY( 57 LIBC_NAMESPACE::pthread_attr_getdetachstate(attr, &detachstate) != 0)) 58 return EINVAL; 59 60 if (attr == &default_attr) 61 // Should we fail here? Its non-issue as the moment as pthread_attr_destroy 62 // can only succeed. 63 if (LIBC_UNLIKELY(LIBC_NAMESPACE::pthread_attr_destroy(&default_attr) != 0)) 64 return EINVAL; 65 66 if (stacksize && stacksize < PTHREAD_STACK_MIN) 67 return EINVAL; 68 69 if (guardsize % EXEC_PAGESIZE != 0) 70 return EINVAL; 71 72 if (detachstate != PTHREAD_CREATE_DETACHED && 73 detachstate != PTHREAD_CREATE_JOINABLE) 74 return EINVAL; 75 76 // Thread::run will check validity of the `stack` argument (stack alignment is 77 // universal, not sure a pthread requirement). 78 79 auto *thread = reinterpret_cast<LIBC_NAMESPACE::Thread *>(th); 80 int result = thread->run(func, arg, stack, stacksize, guardsize, 81 detachstate == PTHREAD_CREATE_DETACHED); 82 if (result != 0 && result != EPERM && result != EINVAL) 83 return EAGAIN; 84 return result; 85 } 86 87 } // namespace LIBC_NAMESPACE 88