static uint64_t dev_urandom()

in src/pal/pal_posix.h [368:409]

• 41 lines of code
• 7 McCabe index (conditional complexity)

    static uint64_t dev_urandom()
    {
      union
      {
        uint64_t result;
        char buffer[sizeof(uint64_t)];
      };
      ssize_t ret;
      int flags = O_RDONLY;
#if defined(O_CLOEXEC)
      flags |= O_CLOEXEC;
#endif
      auto fd = open("/dev/urandom", flags, 0);
      if (fd > 0)
      {
        auto current = std::begin(buffer);
        auto target = std::end(buffer);
        while (auto length = static_cast<size_t>(target - current))
        {
          ret = read(fd, current, length);
          if (ret <= 0)
          {
            if (errno != EAGAIN && errno != EINTR)
            {
              break;
            }
          }
          else
          {
            current += ret;
          }
        }
        ret = close(fd);
        SNMALLOC_ASSERT(0 == ret);
        if (SNMALLOC_LIKELY(target == current))
        {
          return result;
        }
      }

      error("Failed to get system randomness");
    }