source: MondoRescue/branches/2.2.5/mindi-busybox/libbb/crypt_make_salt.c@ 1765

/* vi: set sw=4 ts=4: */
/*
 * crypt_make_salt
 *
 * i64c was also put here, this is the only function that uses it.
 *
 * Lifted from loginutils/passwd.c by Thomas Lundquist <thomasez@zelow.no>
 *
 */

#include "libbb.h"

static int i64c(int i)
{
    i &= 0x3f;
    if (i == 0)
        return '.';
    if (i == 1)
        return '/';
    if (i < 12)
        return ('0' - 2 + i);
    if (i < 38)
        return ('A' - 12 + i);
    return ('a' - 38 + i);
}

int crypt_make_salt(char *p, int cnt, int x)
{
    x += getpid() + time(NULL);
    do {
        /* x = (x*1664525 + 1013904223) % 2^32 generator is lame
         * (low-order bit is not "random", etc...),
         * but for our purposes it is good enough */
        x = x*1664525 + 1013904223;
        /* BTW, Park and Miller's "minimal standard generator" is
         * x = x*16807 % ((2^31)-1)
         * It has no problem with visibly alternating lowest bit
         * but is also weak in cryptographic sense + needs div,
         * which needs more code (and slower) on many CPUs */
        *p++ = i64c(x >> 16);
        *p++ = i64c(x >> 22);
    } while (--cnt);
    *p = '\0';
    return x;
}