/*makepw.c - accept a list of passwords, and save a corresponding list of
  encrypted passwords in the specified file.
  By Matthew Belmonte, October 1997.
  Copyright (c) 1197 by the Howard Hughes Medical Institute.*/

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <stdio.h>
#include <math.h>
#include <errno.h>

/*read a password from standard input*/
void get_password(s)
char *s;
  {
  register int i, c;
  i = 0;
  printf("Password: ");
  while((i != 8) && ((c=getchar()) != EOF) && (c != '\n') && (c != '\r'))
    s[i++] = c;
  if(i == 8)
    while(((c=getchar()) != EOF) && (c != '\n') && (c != '\r'))
      ;
  s[i] = '\0';
  }

/*use the microseconds clock to generate a random seed*/
void set_random_seed()
  {
  struct timeval tv;
  gettimeofday(&tv, (struct timezone *)0);
  srandom((int)(tv.tv_usec >> 4));
  }

/*Generate a random character.  set_random_seed() should have been called
  previously.*/
int get_random_char()
  {
  static char legal_chars[] = ":/0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  return(legal_chars[(int)(random()&63L)]);
  }

/*print an encrypted password (s) into the password file (fp)*/
void store_password(s, fp)
char *s;
FILE *fp;
  {
  char salt[3];
  salt[2] = '\0';
  set_random_seed();
  salt[0] = get_random_char(); 
  salt[1] = get_random_char();
  fprintf(fp, "%s\n", crypt(s, salt));
  }

void main(argc, argv)
int argc;
char **argv;
  {
  FILE *cipherfile;
  char cleartext[81];
  if(argc != 2)
    {
    fprintf(stderr, "usage: %s <encrypted_passwd_file>\n", *argv);
    exit(1);
    }
  umask(0177);
  cipherfile = fopen(argv[1], "w");
  if(cipherfile == NULL)
    {
    perror(argv[1]);
    exit(errno);
    }
  get_password(cleartext);
  while(*cleartext)
    {
    store_password(cleartext, cipherfile);
    get_password(cleartext);
    }
  fclose(cipherfile);
  exit(0);
  }