scottk/UltraGrid
1
0
Fork 0
mirror of https://github.com/outbackdingo/UltraGrid.git synced 2026-03-21 06:40:15 +00:00
Code Issues Packages Projects Releases Wiki Activity

ug_srand->ug_rand_init (improved seeding)

Browse Source 
On POSIX systems, add also clock() to the seed + use as a source also
/dev/random if available.
This commit is contained in:
Martin Pulec
2023-08-07 09:14:27 +02:00
parent a097fe7b09
commit f590145ed3
3 changed files with 33 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
src/host.cpp
View File

@@ -419,8 +419,7 @@ struct init_data *common_preinit(int argc, char *argv[])
open_all("ultragrid_*.so", init.opened_libs); // load modules
}
// init_rng in rtp.c added also hostname to the seed
ug_srand((getpid() * 42) ^ get_time_in_ns());
ug_rand_init();
#ifdef __linux__
mtrace();

36
src/utils/random.c
View File

@@ -1,6 +1,6 @@
/**
* @file utils/random.h
* @author Martin Pulec <pulec@cesnet.cz>
* @file utils/random.c
* @author Martin Pulec <martin.pulec@cesnet.cz>
*/
/*
* Copyright (c) 2023 CESNET, z. s. p. o.
@@ -34,22 +34,46 @@
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @file
* @note
* Remarks (possible improvements):
* - lbl_random reads from '/dev/urandom' instead if available (so Linux only)
* and HAVE_DEV_URANDOM defined (which isn't)
* - init_rng() in rtp.c used also hostname for seeding (but there may not be
* reasonable value, eg. '::1' if no host given to rcvr)
*/
#ifndef _WIN32
#include <stdio.h>
#include <unistd.h>
#endif
#define _CRT_RAND_S // request rand_s (Win)
#include <stdlib.h>
#include "random.h"
#include "tv.h"
/**
* @note
* Windows rand_s() is not supposed to be seeded
* @remark
* thread-safe
*/
void
ug_srand(uint32_t seed)
ug_rand_init(void)
{
#ifdef _WIN32
(void) seed;
#else
#ifndef _WIN32
unsigned seed =
(getpid() * 42) ^ (unsigned) get_time_in_ns() ^ (unsigned) clock();
FILE *dev_r = fopen("/dev/random", "rb");
if (dev_r != NULL) {
unsigned seed_dev_r = 0;
if (fread(&seed_dev_r, sizeof seed_dev_r, 1, dev_r) == 1) {
seed ^= seed_dev_r;
}
fclose(dev_r);
}
srandom(seed);
#endif
}

4
src/utils/random.h
View File

@@ -1,6 +1,6 @@
/**
* @file utils/random.h
* @author Martin Pulec <pulec@cesnet.cz>
* @author Martin Pulec <martin.pulec@cesnet.cz>
*/
/*
* Copyright (c) 2023 CESNET, z. s. p. o.
@@ -43,7 +43,7 @@ extern "C" {
#endif
// functions documented at definition
void ug_srand(uint32_t seed);
void ug_rand_init(void);
uint32_t ug_rand(void);
double ug_drand(void);