1 // Copyright 2015 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // +build cgo 6 // +build darwin dragonfly freebsd linux netbsd openbsd solaris 7 8 #include <pthread.h> 9 #include <errno.h> 10 #include <stdio.h> 11 #include <stdlib.h> 12 #include <string.h> // strerror 13 #include <time.h> 14 #include "libcgo.h" 15 #include "libcgo_unix.h" 16 17 static pthread_cond_t runtime_init_cond = PTHREAD_COND_INITIALIZER; 18 static pthread_mutex_t runtime_init_mu = PTHREAD_MUTEX_INITIALIZER; 19 static int runtime_init_done; 20 21 // The context function, used when tracing back C calls into Go. 22 static void (*cgo_context_function)(struct context_arg*); 23 24 void 25 x_cgo_sys_thread_create(void* (*func)(void*), void* arg) { 26 pthread_t p; 27 int err = _cgo_try_pthread_create(&p, NULL, func, arg); 28 if (err != 0) { 29 fprintf(stderr, "pthread_create failed: %s", strerror(err)); 30 abort(); 31 } 32 } 33 34 uintptr_t 35 _cgo_wait_runtime_init_done() { 36 void (*pfn)(struct context_arg*); 37 38 pthread_mutex_lock(&runtime_init_mu); 39 while (runtime_init_done == 0) { 40 pthread_cond_wait(&runtime_init_cond, &runtime_init_mu); 41 } 42 43 // TODO(iant): For the case of a new C thread calling into Go, such 44 // as when using -buildmode=c-archive, we know that Go runtime 45 // initialization is complete but we do not know that all Go init 46 // functions have been run. We should not fetch cgo_context_function 47 // until they have been, because that is where a call to 48 // SetCgoTraceback is likely to occur. We are going to wait for Go 49 // initialization to be complete anyhow, later, by waiting for 50 // main_init_done to be closed in cgocallbackg1. We should wait here 51 // instead. See also issue #15943. 52 pfn = cgo_context_function; 53 54 pthread_mutex_unlock(&runtime_init_mu); 55 if (pfn != nil) { 56 struct context_arg arg; 57 58 arg.Context = 0; 59 (*pfn)(&arg); 60 return arg.Context; 61 } 62 return 0; 63 } 64 65 void 66 x_cgo_notify_runtime_init_done(void* dummy) { 67 pthread_mutex_lock(&runtime_init_mu); 68 runtime_init_done = 1; 69 pthread_cond_broadcast(&runtime_init_cond); 70 pthread_mutex_unlock(&runtime_init_mu); 71 } 72 73 // Sets the context function to call to record the traceback context 74 // when calling a Go function from C code. Called from runtime.SetCgoTraceback. 75 void x_cgo_set_context_function(void (*context)(struct context_arg*)) { 76 pthread_mutex_lock(&runtime_init_mu); 77 cgo_context_function = context; 78 pthread_mutex_unlock(&runtime_init_mu); 79 } 80 81 // Gets the context function. 82 void (*(_cgo_get_context_function(void)))(struct context_arg*) { 83 void (*ret)(struct context_arg*); 84 85 pthread_mutex_lock(&runtime_init_mu); 86 ret = cgo_context_function; 87 pthread_mutex_unlock(&runtime_init_mu); 88 return ret; 89 } 90 91 // _cgo_try_pthread_create retries pthread_create if it fails with 92 // EAGAIN. 93 int 94 _cgo_try_pthread_create(pthread_t* thread, const pthread_attr_t* attr, void* (*pfn)(void*), void* arg) { 95 int tries; 96 int err; 97 struct timespec ts; 98 99 for (tries = 0; tries < 20; tries++) { 100 err = pthread_create(thread, attr, pfn, arg); 101 if (err == 0) { 102 pthread_detach(*thread); 103 return 0; 104 } 105 if (err != EAGAIN) { 106 return err; 107 } 108 ts.tv_sec = 0; 109 ts.tv_nsec = (tries + 1) * 1000 * 1000; // Milliseconds. 110 nanosleep(&ts, nil); 111 } 112 return EAGAIN; 113 } 114
