-static unsigned char random_buffer[4096];
-static size_t random_left;
-
-/** @brief Fill [buf, buf+n) with random bytes */
-static void random_bytes(unsigned char *buf, size_t n) {
- while(n > 0) {
- if(random_left > 0) {
- const size_t this_time = n > random_left ? random_left : n;
-
- memcpy(buf, random_buffer + random_left - this_time, this_time);
- n -= this_time;
- random_left -= this_time;
- } else {
- static int fd = -1;
- int r;
-
- if(fd < 0) {
- if((fd = open("/dev/urandom", O_RDONLY)) < 0)
- fatal(errno, "opening /dev/urandom");
- }
- if((r = read(fd, random_buffer, sizeof random_buffer)) < 0)
- fatal(errno, "reading /dev/urandom");
- if((size_t)r < sizeof random_buffer)
- fatal(0, "short read from /dev/urandom");
- random_left = sizeof random_buffer;
- }
- }
-}
-