#include <stdio.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/uio.h>

void sigpipe_handler(int dummy)
{
  printf("Pid %d: Caught sigpipe\n", getpid());
  exit(1);
}

#define BSIZE 16000

main(int argc, char **argv)
{
  int p[2];
  int id, i, j;
  char s[BSIZE];
  FILE *f;
  
  signal(SIGPIPE, sigpipe_handler);
  if (argc != 3) { fprintf(stderr, "usage: q4 command-string-1 command-string2\n"); exit(1); }
  pipe(p);
  id = fork();

  if (id == 0) {
    id = 1;
    f = fopen("OC.txt", "w");
    printf("Child is pid %d\n", getpid());
  } else {
    id = 2;
    f = fopen("OP.txt", "w");
    printf("Parent is pid %d\n", getpid());
  }

  for (i = 0; argv[id][i] != '\0'; i++) {
    /* printf("%d: %c\n", id, argv[id][i]); */
    if (argv[id][i] == 'A') close(p[0]);
    if (argv[id][i] == 'B') close(p[1]);
    if (argv[id][i] == 'C') {
      for (j = 0; j < BSIZE-2; j++) s[j] = 'A';
      s[BSIZE-1] = '\n';
      j = write(p[1], s, BSIZE);
    }
    if (argv[id][i] == 'D') {
      j = read(p[0], s, BSIZE);
      if (j != BSIZE) {
        printf("Pid %d: Exit on read from p[0]\n", getpid());
        exit(1);
      }
      fwrite(s, 1, BSIZE, f);
      fflush(f);
    }
    if (argv[id][i] == 'S') sleep(1);
  }
  printf("Pid %d: Normal Exit\n", getpid());
  exit(0);
}