Random in Linux

• Syscall available since kernel 3.17
• Only blocks at initialization if insufficient entropy

$ man 2 getrandom
GETRANDOM(2)                                     Linux Programmer's Manual                                    GETRANDOM(2)

NAME
       getrandom - obtain a series of random bytes

SYNOPSIS
       #include <linux/random.h>

       int getrandom(void *buf, size_t buflen, unsigned int flags);
...

Source Linux kernel random.c