#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

int main(int argc, char **argv)
{
  int fdin, fdout;
  struct stat st;
  char buf[BUFSIZ];
  int n_read;

  if(argc != 3)
  {
    puts("Usage: mycp <source> <destination>");
    exit(1);
  }
  if((fdin = open(argv[1], O_RDONLY)) == -1)
  {
    printf("open(): %s\n", strerror(errno));
    exit(1);
  }
  if(fstat(fdin, &st) == -1)
  {
    printf("stat(): %s\n", strerror(errno));
    exit(1);
  }

  umask(0);
  if((fdout = open(argv[2], O_WRONLY|O_CREAT|O_TRUNC, st.st_mode)) == -1)
  {
    printf("open(): %s\n", strerror(errno));
    exit(1);
  }

  while((n_read = read(fdin, buf, sizeof(buf))) > 0)
  {
    if(write(fdout, buf, n_read) == -1)
    {
      printf("write(): %s\n", strerror(errno));
      exit(1);
    }
  }

  close(fdin);
  close(fdout);

  if(n_read == -1)
  {
    printf("read(): %s\n", strerror(errno));
    exit(1);
  }

  return 0;
}