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/* ISC license. */
#include <unistd.h>
#include <stdint.h>
#include <skalibs/uint32.h>
#include <skalibs/tai.h>
#include <skalibs/sha1.h>
/*
Writes 160 bytes of crap into s.
Certainly not cryptographically secure or 100% unpredictable,
but we're only using this to help shuffle the entropy of
/dev/urandom or to init an internal SURF PRNG.
iow: we are CS iff the system's RNG is CS.
*/
void random_makeseed (char *s)
{
SHA1Schedule bak = SHA1_INIT() ;
{
tain now ;
char tmp[256] ;
uint32_t x = getpid() ;
uint32_pack(tmp, x) ;
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) ;
}
}
}
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