/*
 * crypt(1)
 * A simple command-line interface to crypt(3), without the annoying bugs and
 * limitations of the Other Implementations.
 *
 * Author: Greg Wooledge <greg@wooledge.org>
 * Version: 0.2
 * Last modified: 2013-03-29
 * License: Public domain
 * WWW: http://wooledge.org/~greg/crypt/
 */

/*
 * Sample build command:
 * cc -o crypt crypt.c
 */

/*
 * If you're compiling this on a GNU libc system, you may have to link with
 * -lcrypt.  The cryptographic library is separate from the rest of the GNU
 * libc because of the (former) US export regulations concerning cryptographic
 * software.  Gee, thanks, guys!
 */

#define _XOPEN_SOURCE	/* GNU libc newer than (?) requires this */
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

void help(int ret);

int main(int argc, char *argv[]) {
    char *salt, s[3];
    int ret;

    if (argc <= 1 || argc > 3) {
        help(1);
    } else if (argc == 2) {
	const char SALT[] =
	    "./0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
        srand(time(NULL));
        s[0] = SALT[rand() % sizeof(SALT)];
        s[1] = SALT[rand() % sizeof(SALT)];
	s[2] = '\0';
	salt = s;
    } else {
        salt = argv[2];
    }
    ret = puts(crypt(argv[1], salt));
    return (ret != EOF);
}

void help(int ret) {
    puts("Usage: crypt password [salt]");
    puts("  If salt is omitted, a random two-character (DES) salt is chosen.");
    puts("  The permitted types of salt are system-specific; see crypt(3).");
    exit(ret);
}