// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 */

#include <assert.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <sys/mman.h>
#include <linux/mman.h>

#include "kselftest.h"

int main(int argc, char *argv[])
{
        size_t alloc_size = 134217728;
        size_t page_size = getpagesize();
        void *alloc;
        pid_t child;

        ksft_print_header();
        ksft_set_plan(1);

        alloc = mmap(0, alloc_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_DROPPABLE, -1, 0);
        assert(alloc != MAP_FAILED);
        memset(alloc, 'A', alloc_size);
        for (size_t i = 0; i < alloc_size; i += page_size)
                assert(*(uint8_t *)(alloc + i));

        child = fork();
        assert(child >= 0);
        if (!child) {
                for (;;)
                        *(char *)malloc(page_size) = 'B';
        }

        for (bool done = false; !done;) {
                for (size_t i = 0; i < alloc_size; i += page_size) {
                        if (!*(uint8_t *)(alloc + i)) {
                                done = true;
                                break;
                        }
                }
        }
        kill(child, SIGTERM);

        ksft_test_result_pass("MAP_DROPPABLE: PASS\n");
        exit(KSFT_PASS);
}