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busybox/libbb/crypt_make_salt.c
Denis Vlasenko defc1ea340 *: introduce and use FAST_FUNC: regparm on i386, otherwise no-on
text    data     bss     dec     hex filename
 808035     611    6868  815514   c719a busybox_old
 804472     611    6868  811951   c63af busybox_unstripped
2008-06-27 02:52:20 +00:00

46 lines
1.0 KiB
C

/* 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 FAST_FUNC 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;
}