Stop child from reciving SIGINT from parent proccess

Question

I have been trying to prevent my parent thread from killing the child proccess if the parent proccess recives a ctrl-C signal. I have run out of ideas.

The parent proccess allready catches SIGINT and so i want the same as now the children dies.

  int main() {
       pid_t pid;

       pid = fork();

       if(pid > 0) {
          /*Parent proccess*/
          [...other code...]
       } else {
          /*Child proccess*/

           signal(SIGINT, SIG_IGN);     //does not work
           sigaction(SIGINT, &action, 0);  //does not work either
           [...other code...]
       }

  }

Ideas?

What is the goal to hold the child alive if the parent process is dead? — Leo Chapiro, Dec 16 '15 at 12:05
Possible duplicate of [Linux daemonize](http://stackoverflow.com/questions/3095566/linux-daemonize) — ecatmur, Dec 16 '15 at 12:09
Why does the child gets signalled at all when the parent ends? — alk, Dec 16 '15 at 12:18
It usually doesn't, but ctrl+c sends sigint to the whole foreground process-group, not just to the parent process. The OP could try to use setsid() instead of trying to catch the signal. — Ctx, Dec 16 '15 at 12:19
The parent proccess allready catches SIGINT and so i want the same as now the children dies. — user1501127, Dec 16 '15 at 12:29
do you by chance exec*() after the fork()? This will reset all signal handlers to default — Ctx, Dec 16 '15 at 12:31
Yes! ahh so thats it then, i do execvp(). But should not the sig* in parent/child code work for the new proccess? — user1501127, Dec 16 '15 at 12:53
File handles, env vars, and process groups are kernel properties. Signal handers are user-space properties. Nothing user-space survives exec. — ams, Dec 16 '15 at 13:14

score 2 · Accepted Answer · answered Dec 16 '15 at 16:07

2

SIGINT is sent to the entire process group. Try using setpgrp(); in the child process to put it into a different process group.

answered Dec 16 '15 at 16:07

Duane McCully

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Stop child from reciving SIGINT from parent proccess

1 Answers1