#!/usr/bin/env python3
"""
Simplest program that tries to allocate a large amount of RAM.

malloc lies on Linux by default, so we use memset to force the
kernel to actually give us real memory.

NOTE: This file has to be duplicated & present in all the following locations:
 - tests/memlimit/dockerfile/postBuild
 - tests/memlimit/dockerfile/postBuild
See https://github.com/jupyterhub/repo2docker/issues/160 for reason
"""
import os
from ctypes import c_void_p, cdll, memset

libc = cdll.LoadLibrary("libc.so.6")
libc.malloc.restype = c_void_p

with open("mem_allocate_mb") as f:
    mem_allocate_mb = int(f.read().strip())

size = 1024 * 1024 * mem_allocate_mb
print(f"trying to allocate {mem_allocate_mb}MB")

ret = libc.malloc(size)

memset(ret, 0, size)