#include <unistd.h>
#include <fcntl.h>
#include <errno.h>


#define BUFSIZE 512    /* size of chunk to be read */
#define PERM    0644   /* file permission of new file */  

int copyfile(const char *name1, const char *name2);


int main(argc, argv)
     int argc;
     char *argv[];
{
  if (argc < 3) {
    printf("Usage: mycp <filename> <new file>\n\n");
    return -1;
  }  // end if argc < 3

  if (copyfile(argv[1], argv[2]) == 0)
    return 0;
  else
    return -1;
}


int copyfile(const char *name1, const char *name2)
 {
  int infile, outfile;
  ssize_t nread;
  char buffer[BUFSIZE];

  if ((infile = open(name1, O_RDONLY)) == -1)   {
    perror("Error opening file1: %s", name1);
    return -1;
  }

  if ((outfile = open(name2, O_WRONLY | O_CREAT | O_TRUNC, PERM)) == -1)   {
    close(infile);
    perror("Error opening file2: %s", name2);
    return -2;
  }

  while ((nread = read(infile, buffer, BUFSIZE)) > 0) {
    if (write(outfile, buffer, nread) < nread) {
      close(infile);
      close(outfile);
      perror("Error writing to file2");
      return -3;
    }  // end if
  }  // end while

  close(infile);
  close(outfile);

  return 0;
 }