On Thu, Mar 29, 2018 at 6:34 PM, hexun via golang-nuts
<golang-nuts@googlegroups.com> wrote:
> func mustSendSIGSEGV(){
> defer func() {
> if err := recover(); err != nil {
> fmt.Print("enter recover 111")
> // logger.PrintPanicStack()
> }
> }()
> var r *Test
> r.Num = 0
> }
> i rewrite mustSendSIGSEGV like this。it is same as before.. how to modify
> the default Go SIGSEGV handler?
When you install your own SIGSEGV handler, you are replacing the Go handler.
You can't really modify the Go handler. You can use the os/signal
package to catch a SIGSEGV signal sent to the process, but it won't
catch a SIGSEGV caused by the process.
What are you really trying to do?
Ian
> 在 2018年3月30日星期五 UTC+8上午12:42:42，Ian Lance Taylor写道：
>>
>> On Thu, Mar 29, 2018 at 8:48 AM, hexun via golang-nuts
>> <golan...@googlegroups.com> wrote:
>> > From "The Go Programming Language" I see this:
>> >
>> > If the non-Go code installs any signal handlers, it must use the
>> > SA_ONSTACK
>> > flag with sigaction. Failing to do so is likely to cause the program to
>> > crash if the signal is received.
>> >
>> >
>> >
>> >
>> > Can any one tell me why syscall.Kill(pid, syscall.SIGSEGV) only print
>> > "handlerSIGSEGV Sent by 0" once ,but mustSendSIGSEGV will print
>> > "handlerSIGSEGV Sent by 0" Unlimited times。 I want golang SIGSEGV pass
>> > to c
>> > ,only handle once ,not many times.can anyone help me?
>> > package main
>> > /*
>> > #include <stdio.h>
>> > #include <signal.h>
>> > #include <string.h>
>> >
>> > struct sigaction old_action;
>> >
>> >
>> > void handlerSIGSEGV(int signum, siginfo_t *info, void *context) {
>> > printf("handlerSIGSEGV Sent by %d\n", info->si_pid);
>> > }
>> >
>> >
>> >
>> > void testSIGSEGV() {
>> > struct sigaction action;
>> > sigaction(SIGSEGV, NULL, &action);
>> > memset(&action, 0, sizeof action);
>> > sigfillset(&action.sa_mask);
>> > action.sa_sigaction = handlerSIGSEGV;
>> > action.sa_flags = SA_NOCLDSTOP | SA_SIGINFO | SA_ONSTACK;
>> > sigaction(SIGSEGV, &action, &old_action);
>> > }
>> > */
>> > import "C"
>> >
>> > import (
>> > "os"
>> > "syscall"
>> > "time"
>> > "fmt"
>> > )
>> > type Test struct {
>> > Num int
>> > }
>> >
>> > func mustSendSIGSEGV(){
>> > var r *Test
>> > r.Num = 0
>> > }
>> >
>> > func main() {
>> > // C.test()
>> > C.testSIGSEGV()
>> > pid := os.Getpid()
>> > syscall.Kill(pid, syscall.SIGSEGV)
>> > // mustSendSIGSEGV()
>> > for {
>> > // syscall.Kill(pid, syscall.SIGUSR1)
>> > fmt.Print("33")
>> > time.Sleep(time.Second)
>> > }
>> > }
>>
>> Your SIGSEGV handler just returns, which means that the program
>> resumes execution at the point of failure. In your mustSendSIGSEGV
>> function you haven't done anything to fix the code, so it just gets
>> another SIGSEGV.
>>
>> Note that the default Go SIGSEGV handler does not simply return. It
>> panics.
>>
>> Ian
>
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