// sigtst.c
#include <signal.h>
#include <stdio.h>

#define SET0(str) str[sizeof(str)- 1 ]= 0 

void my_action(int sig, siginfo_t *si, void * p) {
 char path[ 1024 ];
 char lnk[ 1024 ];

 lnk[ 0 ]= 0 ; SET0(lnk); SET0(path);
 snprintf(path,sizeof(path)- 1 ,"/proc/%u/fd/0",si->si_pid);
 readlink(path,lnk,sizeof(lnk)- 1 );

 printf("Got signal %i from pid %i, term=%s (%s)\n",
  si->si_signo,si->si_pid,lnk, path);

 if (lnk[ 0 ]) {
  snprintf(path,sizeof(path)- 1 ,"echo Hello  > %s",lnk);
  system(path);
 } else perror("readlink");

 return;
}

main() {
 struct sigaction act;

 act.sa_flags=SA_SIGINFO;
 act.sa_sigaction=my_action;
 sigemptyset(&act.sa_mask);
 sigaction(SIGTERM,&act,NULL);

 while( 1 ) {sleep( 1 );}
}