golang sigstack 代码
文件路径：/src/runtime/testdata/testprogcgo/sigstack.go
/ Copyright 2017 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 !plan9 && !windows
/ +build !plan9,!windows
/ Test handling of Go-allocated signal stacks when calling from
/ C-created threads with and without signal stacks. (See issue
/ #22930.)
package main
/*
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#ifdef _AIX
/ On AIX, SIGSTKSZ is too small to handle Go sighandler.
#define CSIGSTKSZ 0x4000
#else
#define CSIGSTKSZ SIGSTKSZ
#endif
extern void SigStackCallback();
static void* WithSigStack(void* arg __attribute__((unused))) {
/ Set up an alternate system stack.
void* base = mmap(0, CSIGSTKSZ, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
if (base == MAP_FAILED) {
perror("mmap failed");
abort();
}
stack_t st = {}, ost = {};
st.ss_sp = (char*)base;
st.ss_flags = 0;
st.ss_size = CSIGSTKSZ;
if (sigaltstack(&st, &ost) < 0) {
perror("sigaltstack failed");
abort();
}
/ Call Go.
SigStackCallback();
/ Disable signal stack and protect it so we can detect reuse.
if (ost.ss_flags & SS_DISABLE) {
/ Darwin libsystem has a bug where it checks ss_size
/ even if SS_DISABLE is set. (The kernel gets it right.)
ost.ss_size = CSIGSTKSZ;
}
if (sigaltstack(&ost, NULL) < 0) {
perror("sigaltstack restore failed");
abort();
}
mprotect(base, CSIGSTKSZ, PROT_NONE);
return NULL;
}
static void* WithoutSigStack(void* arg __attribute__((unused))) {
SigStackCallback();
return NULL;
}
static void DoThread(int sigstack) {
pthread_t tid;
if (sigstack) {
pthread_create(&tid, NULL, WithSigStack, NULL);
} else {
pthread_create(&tid, NULL, WithoutSigStack, NULL);
}
pthread_join(tid, NULL);
}
*/
import "C"
func init() {
register("SigStack", SigStack)
}
func SigStack() {
C.DoThread(0)
C.DoThread(1)
C.DoThread(0)
C.DoThread(1)
println("OK")
}
var BadPtr *int
/export SigStackCallback
func SigStackCallback() {
/ Cause the Go signal handler to run.
defer func() { recover() }()
*BadPtr = 42
}