From 71811470be4f182b623510cf92ea5cfff16df172 Mon Sep 17 00:00:00 2001 From: Mattias Andrée Date: Sun, 28 Jan 2024 16:34:27 +0100 Subject: Add libsimple_generate_seed and libsimple_srand MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Mattias Andrée --- generate_seed.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 generate_seed.c (limited to 'generate_seed.c') diff --git a/generate_seed.c b/generate_seed.c new file mode 100644 index 0000000..cce274f --- /dev/null +++ b/generate_seed.c @@ -0,0 +1,59 @@ +/* See LICENSE file for copyright and license details. */ +#include "common.h" +#ifndef TEST + +#include + + +unsigned int +libsimple_generate_seed(void) /* TODO add test */ +{ + uintptr_t longseed = 1; + void *ptr; + uintptr_t ptri; + unsigned int seed; + struct timespec ts; + uint8_t (*at_random)[16]; + size_t i; + + if (!clock_gettime(CLOCK_REALTIME, &ts)) + longseed ^= (uintptr_t)ts.tv_sec * (uintptr_t)1000000000UL + (uintptr_t)ts.tv_nsec; + + ptr = malloc(1); + ptri = (uintptr_t)ptr; + free(ptr); + longseed ^= ptri; + longseed ^= (uintptr_t)&ptri; + longseed ^= (uintptr_t)clock(); + + if (!clock_gettime(CLOCK_MONOTONIC_RAW, &ts)) + longseed ^= (uintptr_t)ts.tv_sec * (uintptr_t)1000000000UL + (uintptr_t)ts.tv_nsec; + + ptri = (uintptr_t)getauxval(AT_RANDOM); + if (ptri) { + at_random = (void *)ptri; + for (i = 0; i < ELEMSOF(*at_random); i++) + longseed ^= (*at_random)[i] << (i % sizeof(longseed) * (size_t)CHAR_BIT); + } + + seed = 0; + while (longseed) { + seed ^= (unsigned int)longseed; + longseed >>= sizeof(unsigned int) * (CHAR_BIT - 1); + longseed >>= sizeof(unsigned int); + } + + return seed; +} + + +#else +#include "test.h" + +int +main(void) +{ + return 0; +} + +#endif -- cgit v1.2.3-70-g09d2