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// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build unix
#include <pthread.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h> // strerror
#include <time.h>
#include "libcgo.h"
#include "libcgo_unix.h"
static pthread_cond_t runtime_init_cond = PTHREAD_COND_INITIALIZER;
static pthread_mutex_t runtime_init_mu = PTHREAD_MUTEX_INITIALIZER;
static int runtime_init_done;
// The context function, used when tracing back C calls into Go.
static void (*cgo_context_function)(struct context_arg*);
void
x_cgo_sys_thread_create(void* (*func)(void*), void* arg) {
pthread_t p;
int err = _cgo_try_pthread_create(&p, NULL, func, arg);
if (err != 0) {
fprintf(stderr, "pthread_create failed: %s", strerror(err));
abort();
}
}
uintptr_t
_cgo_wait_runtime_init_done(void) {
void (*pfn)(struct context_arg*);
pthread_mutex_lock(&runtime_init_mu);
while (runtime_init_done == 0) {
pthread_cond_wait(&runtime_init_cond, &runtime_init_mu);
}
// TODO(iant): For the case of a new C thread calling into Go, such
// as when using -buildmode=c-archive, we know that Go runtime
// initialization is complete but we do not know that all Go init
// functions have been run. We should not fetch cgo_context_function
// until they have been, because that is where a call to
// SetCgoTraceback is likely to occur. We are going to wait for Go
// initialization to be complete anyhow, later, by waiting for
// main_init_done to be closed in cgocallbackg1. We should wait here
// instead. See also issue #15943.
pfn = cgo_context_function;
pthread_mutex_unlock(&runtime_init_mu);
if (pfn != nil) {
struct context_arg arg;
arg.Context = 0;
(*pfn)(&arg);
return arg.Context;
}
return 0;
}
void
x_cgo_notify_runtime_init_done(void* dummy __attribute__ ((unused))) {
pthread_mutex_lock(&runtime_init_mu);
runtime_init_done = 1;
pthread_cond_broadcast(&runtime_init_cond);
pthread_mutex_unlock(&runtime_init_mu);
}
// Sets the context function to call to record the traceback context
// when calling a Go function from C code. Called from runtime.SetCgoTraceback.
void x_cgo_set_context_function(void (*context)(struct context_arg*)) {
pthread_mutex_lock(&runtime_init_mu);
cgo_context_function = context;
pthread_mutex_unlock(&runtime_init_mu);
}
// Gets the context function.
void (*(_cgo_get_context_function(void)))(struct context_arg*) {
void (*ret)(struct context_arg*);
pthread_mutex_lock(&runtime_init_mu);
ret = cgo_context_function;
pthread_mutex_unlock(&runtime_init_mu);
return ret;
}
// _cgo_try_pthread_create retries pthread_create if it fails with
// EAGAIN.
int
_cgo_try_pthread_create(pthread_t* thread, const pthread_attr_t* attr, void* (*pfn)(void*), void* arg) {
int tries;
int err;
struct timespec ts;
for (tries = 0; tries < 20; tries++) {
err = pthread_create(thread, attr, pfn, arg);
if (err == 0) {
pthread_detach(*thread);
return 0;
}
if (err != EAGAIN) {
return err;
}
ts.tv_sec = 0;
ts.tv_nsec = (tries + 1) * 1000 * 1000; // Milliseconds.
nanosleep(&ts, nil);
}
return EAGAIN;
}
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