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/* ISC license. */
#include <unistd.h>
#include <stdint.h>
#include <skalibs/uint32.h>
#include <skalibs/tai.h>
#include <skalibs/sha1.h>
#include <skalibs/surf.h>
/*
Writes 160 bytes of crap into s.
Certainly not cryptographically secure or 100% unpredictable,
but we're only using this to seed a fallback internal PRNG.
*/
static void makeseed (char *s)
{
SHA1Schedule bak = SHA1_INIT() ;
{
tain now ;
char tmp[256] ;
uint32_t x = getpid() ;
uint32_pack(tmp, x) ; /* if valgrind sends you here, tell it to stfu */
x = getppid() ;
uint32_pack(tmp + 4, x) ;
tain_now(&now) ;
tain_pack(tmp + 8, &now) ;
sha1_update(&bak, tmp, 8 + TAIN_PACK) ;
gethostname(tmp, 256) ;
sha1_update(&bak, tmp, 256) ;
sha1_final(&bak, tmp) ;
sha1_init(&bak) ;
sha1_update(&bak, tmp, 20) ;
}
{
char i = 0 ;
for (; i < 8 ; i++)
{
SHA1Schedule ctx = bak ;
sha1_update(&ctx, &i, 1) ;
sha1_final(&ctx, s + 20*i) ;
}
}
}
void autosurf (char *s, size_t n)
{
static SURFSchedule ctx = SURFSCHEDULE_ZERO ;
static int need4seed = 1 ;
if (need4seed)
{
char seed[160] ;
makeseed(seed) ;
surf_init(&ctx, seed) ;
need4seed = 0 ;
}
surf(&ctx, s, n) ;
}
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