int
main() {
/* read and write pipes file descriptions, from the perspective of the parent process */
int writePfd[2], readPfd[2];
long childPid;
/* create read and write pipes */
if (pipe(writePfd) == -1)
pexit("pipe");
if (pipe(readPfd) == -1)
pexit("pipe");
childPid = fork();
switch (childPid) {
case -1:
pexit("fork");
case 0:
/* child process: closes the write end of the write pipe, and the read end of the read pipe. */
if (close(writePfd[1]) == -1)
pexit("close write end of write pipe - child");
if (close(readPfd[0]) == -1)
pexit("close read end of read pipe - child");
childLoop(writePfd[0], readPfd[1]);
/* child loop is finished: this means that the parent process received EOF,
* and the write end of writePfd was closed */
_exit(EXIT_SUCCESS);
default:
/* parent process: closes the read end of the write pipe, and the write end of the read pipe */
if (close(writePfd[0]) == -1)
pexit("close read end of write pipe - parent");
if (close(readPfd[1]) == -1)
pexit("close write end of read pipe - parent");
parentLoop(readPfd[0], writePfd[1]);
/* EOF received. Close write end of writePfd */
if (close(writePfd[1]) == -1)
pexit("close write end of write pipe - parent");
printf("\n");
}
/* parent: wait for the child to die and terminate */
wait(NULL);
exit(EXIT_SUCCESS);
}
/* Daemonize */
void
detach(void)
{
int pid;
pid=fork();
switch(pid) {
case -1:
perror("fork");
exit(1);
break;
case 0:
childLoop();
break;
default:
exit(0);
}
}