[PATCH v3 1/2] support: Add support_socket_so_timestamp_time64

[Florian Weimer]

* Adhemerval Zanella:

> +bool
> +support_socket_so_timestamp_time64 (int fd)
> +{
> +#ifdef __linux__
> +# if __LINUX_KERNEL_VERSION >= 0x050100                          \
> +   || __WORDSIZE == 64                                           \
> +   || (defined __SYSCALL_WORDSIZE && __SYSCALL_WORDSIZE == 64)
> +  return true;
> +# else
> +  int level = SOL_SOCKET;
> +  int optname = COMPAT_SO_TIMESTAMP_NEW;
> +  int optval;
> +  socklen_t len = sizeof (optval);
> +
> +  int r = syscall (__NR_getsockopt, fd, level, optname, &optval, &len);
> +#  ifdef __NR_socketcall
> +  if (r == -1 && errno == ENOSYS)
> +    {
> +      long int args[] = { fd, level, optname, (long int) &optval,
> +			  sizeof (optval) };
> +      r = syscall (__NR_socketcall, 15 /* SOCKOP_getsockopt  */ , args);
> +    }
> +#  endif
> +  return r != -1;
> +# endif
> +#else
> +  return false;
> +#endif
> +}

Is the socketcall fallback really required?  Why would anyone backport
time64 support without also backporting direct system call support?

Thanks,
Florian