#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/file.h>

void doexit(int sig)

{
        printf("exiting parent\n");
        exit(0);
}

int main()

{
        FILE *f;
        int fd;
        
        if (fork()) {
                printf("in parent\n");
                if (signal(SIGTERM, doexit) == SIG_ERR) {
                        printf("problem setting SIGTERM\n");
                        exit(2);
                }
                // syslog does this to give the child enough
                // time to take over logging
                sleep(300);
                
                // this should not be seen, the child should
                // kill the parent before the parent can get
                // past the sleep
                printf("should not have made it this far\n");
                exit(1);
        }
        printf("in child\n");
        printf("pid %d\n", getpid());
        printf("ppid %d\n", getppid());

        // make a small delay to make sure all signals are setup
        sleep(1);       
        
        // the following file operations are taken from syslogd.c
        if ( ((fd = open("fork.lock", O_RDWR|O_CREAT, 0644)) == -1)
                || ((f = fdopen(fd, "r+")) == NULL) ) {
                fprintf(stderr, "Can't open or create fork.lock.\n");
                exit(1);
        }
        if (flock(fd, LOCK_EX|LOCK_NB) == -1) {
                printf("Can't lock fork.lock\n");
                exit(1);
        }
        
        // this is how syslog kills off the parent      
        kill(getppid(), SIGTERM);

        printf("in child after killing parent\n");
        
        exit(0);
}