исполнение random

./js/src/jsmath.cpp
./js/src/jsmath.h

#if defined(XP_WIN)                                                                                                                                                                      
    MOZ_ALWAYS_TRUE(RtlGenRandom(&seed, sizeof(seed)));                                                                                                                                  
#elif defined(HAVE_ARC4RANDOM)                                                                                                                                                           
    seed = (static_cast<uint64_t>(arc4random()) << 32) | arc4random();                                                                                                                   
#elif defined(XP_UNIX)                                                                                                                                                                   
    bool done = false;                                                                                                                                                                   
# if defined(__linux__)                                                                                                                                                                  
    // Try the relatively new getrandom syscall first. It's the preferred way                                                                                                            
    // on Linux as /dev/urandom may not work inside chroots and is harder to                                                                                                             
    // sandbox (see bug 995069).                                                                                                                                                         
    int ret = syscall(SYS_getrandom, &seed, sizeof(seed), GRND_NONBLOCK);                                                                                                                
    done = (ret == sizeof(seed));                                                                                                                                                        
# endif                                                                                                                                                                                  
    if (!done) {                                                                                                                                                                         
        int fd = open("/dev/urandom", O_RDONLY);                                                                                                                                         
        if (fd >= 0) {                                                                                                                                                                   
            mozilla::Unused << read(fd, static_cast<void*>(&seed), sizeof(seed));                                                                                                        
            close(fd);                                                                                                                                                                   
        }                                                                                                                                                                                
    }                                                                                                                                                                                    
#else                                                                                                                                                                                    
# error "Platform needs to implement GenerateRandomSeed()"                                                                                                                               
#endif