Re: [Cppcms-users] Segmentaion fault occurs to booster::aio::io_service running in booster::thread

[CN <cn...@fa...>]

I am trying to implement a mechanism so that the program catches SIGHUP
signal and accordingly reloads configuration file as suggested here:
http://cppcms.com/wikipp/en/page/cppcms_1x_reload_application
 
The signals handler installed by
void service::setup_exit_handling()
in file "service.cpp" simply calls cppcms::service::shutdown(). I
therefore have to roll my own.
 
Regarding the log of gdb backtrace, I seem to have encountered some
trouble - upon the arrival of signal HUP, the process straightly
disappears from gdb's control without trace leaving command
"backtrace" useless.
I am still trying to figure out how. I will post it as soon as I have
it.
 
Best regards,
CN
 
 
On Mon, May 9, 2016, at 06:36 PM, Artyom Beilis wrote:
> 1st why are you using your own signal handler instead of one used
> by CppCMS?
> On segfault - can you show the backtrace of the stack from gdb when it
> happens.
>
>
> Artyom
>
>> **From:** CN <cn...@fa...> **To:** cppcms-
>> us...@li... **Sent:** Sunday, May 8, 2016 5:04 PM
>> **Subject:** [Cppcms-users] Segmentaion fault occurs to
>> booster::aio::io_service running in booster::thread
>>
>> File "t.cpp":
>>
>> #include <booster/aio/io_service.h>
>> #include <cppcms/service.h>
>> #include <boost/bind.hpp>
>> #include <booster/shared_ptr.h>
>> #include <booster/log.h>
>> #include <signal.h>
>> booster::shared_ptr<cppcms::service> this_cppcms_service;
>> static int caught_signal=-1;
>>
>> void signal_handler(int signal_number)
>> {
>> BOOSTER_DEBUG("begin handler");
>> caught_signal=signal_number;
>> this_cppcms_service->shutdown();
>> BOOSTER_DEBUG("end handler");
>> }
>>
>> class my_class {
>> private:
>> booster::aio::io_service io_service;
>> public:
>> void start(){
>> io_service.run();
>> }
>> void stop(){
>> io_service.stop();
>> }
>> };
>>
>>
>> int main(int argc,char ** argv)
>> {
>> while(true){
>> try{
>> this_cppcms_service.reset(new
>> cppcms::service(argc,argv));
>> //Install signals catchers.
>> struct sigaction actions;
>> memset(&actions,0,sizeof(actions));
>> actions.sa_handler=signal_handler;
>> int result;
>> if(
>> (result=sigaction(SIGTERM,&actions,NULL))
>> != 0
>> ||
>> (result=sigaction(SIGHUP,&actions,NULL))
>> != 0
>> ){
>> BOOSTER_ERROR("") << "sigaction()
>> failed";
>> exit(EXIT_FAILURE);
>> }
>> my_class mc;
>> booster::thread
>> mc_thread(boost::bind(&my_class::start,&mc));
>>
>> BOOSTER_DEBUG("==1==");
>> this_cppcms_service->run();
>> BOOSTER_DEBUG("==2==");
>> mc.stop(); mc_thread.join();
>> BOOSTER_DEBUG("==3==");
>> if(caught_signal == SIGTERM)
>> return 0;
>> BOOSTER_DEBUG("==4==");
>> //SIGHUP to reload configurations
>> }
>> catch(std::exception const &e){
>> BOOSTER_ERROR("") << e.what();
>> return 1;
>> }
>> }
>> return 0;
>> }
>>
>> ----------
>>
>> File "t.js":
>>
>> {
>> "service" : {
>> "api" : "fastcgi",
>> "socket" : "/tmp/t.sock",
>> "disable_global_exit_handling":true
>> },
>> "daemon":{
>> "enable":true,
>> "lock":"/tmp/t.pid"
>> },
>> "logging" : {
>> "level" : "debug",
>> "stderr" : false,
>> "syslog" : {
>> "enable":true,
>> "id" : "t"
>> }
>> }
>> }
>>
>> --------
>>
>> Commands issued:
>>
>> cd /tmp
>> g++ -lbooster -lcppcms -lboost_system t.cpp
>> ./a.out -c t.js
>> kill -TERM `cat t.pid`
>>
>> --------
>>
>> File "/var/log/syslog":
>>
>> May  8 21:36:13 host t: ==1==:  (t.cpp:51)
>> May  8 21:36:36 host t: begin handler:  (t.cpp:12)
>> May  8 21:36:36 host t: end handler:  (t.cpp:15)
>> May  8 21:36:36 host t: ==2==:  (t.cpp:53)
>> May  8 21:36:36 host kernel: a.out[5146]: segfault at b5b5dba8 ip
>> b715205e sp bfad0620 error 4 in libpthread-2.19.so[b714a000+18000]
>>
>>
>> With this simple code, I get segfault at "mc.stop();
>> mc_thread.join();"
>> after issuing command "kill -TERM <pid>". Would someone please
>> enlighten
>> me why?
>>
>> Best regards,
>> CN
>>
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