helpers/local/security.AltSyscall.read.c

/*
 * Copyright (c) 2015 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>

#include <sys/stat.h>
#include <sys/types.h>

int main(void) {
  char buf[128];
  int fd, ret;
  unsigned int i;

  fd = open("/dev/zero", O_RDONLY);
  if (fd < 0)
    return 1;

  ret = read(fd, buf, sizeof(buf));
  if (ret < 0)
    return 2;

  for (i = 0; i < (sizeof(buf) / sizeof(buf[0])); i++) {
    if (buf[i] != 0)
      return 3;
  }

  ret = close(fd);
  if (ret < 0)
    return 4;

  return 0;
}