6e5cb299dd
Basically, `devtools/reduce-includes.sh */*.c`. Build time from make clean (RUST=0) (includes building external libs): Before: real 0m38.944000-40.416000(40.1131+/-0.4)s user 3m6.790000-17.159000(15.0571+/-2.8)s sys 0m35.304000-37.336000(36.8942+/-0.57)s After: real 0m37.872000-39.974000(39.5466+/-0.59)s user 3m1.211000-14.968000(12.4556+/-3.9)s sys 0m35.008000-36.830000(36.4143+/-0.5)s Build time after touch config.vars (RUST=0): Before: real 0m19.831000-21.862000(21.5528+/-0.58)s user 2m15.361000-30.731000(28.4798+/-4.4)s sys 0m21.056000-22.339000(22.0346+/-0.35)s After: real 0m18.384000-21.307000(20.8605+/-0.92)s user 2m5.585000-26.843000(23.6017+/-6.7)s sys 0m19.650000-22.003000(21.4943+/-0.69)s Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
88 lines
1.8 KiB
C
88 lines
1.8 KiB
C
#include "config.h"
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#include <assert.h>
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#include <ccan/crypto/sha256/sha256.h>
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#include <ccan/isaac/isaac64.h>
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#include <ccan/tal/tal.h>
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#include <common/pseudorand.h>
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#include <sodium/randombytes.h>
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static struct isaac64_ctx isaac64;
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static struct siphash_seed siphashseed;
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static bool pseudorand_initted = false;
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static void init_if_needed(void)
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{
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if (unlikely(!pseudorand_initted)) {
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unsigned char seedbuf[16];
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struct sha256 sha;
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randombytes_buf(seedbuf, sizeof(seedbuf));
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memcpy(&siphashseed, seedbuf, sizeof(siphashseed));
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/* In case isaac is reversible, don't leak seed. */
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sha256(&sha, seedbuf, sizeof(seedbuf));
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isaac64_init(&isaac64, sha.u.u8, sizeof(sha.u.u8));
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pseudorand_initted = true;
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}
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}
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uint64_t pseudorand(uint64_t max)
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{
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init_if_needed();
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assert(max);
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return isaac64_next_uint(&isaac64, max);
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}
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uint64_t pseudorand_u64(void)
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{
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init_if_needed();
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return isaac64_next_uint64(&isaac64);
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}
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double pseudorand_double(void)
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{
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init_if_needed();
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return isaac64_next_double(&isaac64);
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}
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const struct siphash_seed *siphash_seed(void)
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{
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init_if_needed();
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return &siphashseed;
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}
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void tal_arr_randomize_(void *arr, size_t elemsize)
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{
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/* Easier arith. */
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char *carr = arr;
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size_t n = tal_bytelen(arr) / elemsize;
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assert(tal_bytelen(arr) % elemsize == 0);
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/* From Wikipedia's Fischer-Yates shuffle article:
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*
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* for i from 0 to n−2 do
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* j ← random integer such that i ≤ j < n
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* exchange a[i] and a[j]
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*/
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if (n < 2)
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return;
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for (size_t i = 0; i < n - 1; i++) {
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size_t j = i + pseudorand(n - i);
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char tmp[elemsize];
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/* Technically, memcpy in place is undefined (src and dest overlap). */
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if (j == i)
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continue;
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memcpy(tmp, carr + i * elemsize, elemsize);
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memcpy(carr + i * elemsize, carr + j * elemsize, elemsize);
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memcpy(carr + j * elemsize, tmp, elemsize);
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}
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}
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