ndhc/ncmlib/random.c

39 lines
861 B
C

#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "log.h"
#include "io.h"
// Generate a 32-bit pseudorandom number using libc rand()
uint32_t libc_random_u32(void)
{
static int initialized;
if (initialized)
return rand();
uint32_t seed;
int fd = open("/dev/urandom", O_RDONLY);
if (fd != -1) {
int r = safe_read(fd, (char *)&seed, sizeof seed);
if (r == -1) {
log_warning("Could not read /dev/urandom: %s", strerror(errno));
close(fd);
seed = time(0);
}
} else {
log_warning("Could not open /dev/urandom: %s", strerror(errno));
seed = time(0);
}
srand(seed);
initialized = 1;
return rand();
}