/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <AK/Types.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/internals.h>
#include <unistd.h>

#ifndef _DYNAMIC_LOADER
extern "C" {

extern size_t __stack_chk_guard;
extern bool s_global_initializers_ran;

int main(int, char**, char**);

// Tell the compiler that this may be called from somewhere else.
int _entry(int argc, char** argv, char** env) __attribute__((used));
void _start(int, char**, char**) __attribute__((used));

NAKED void _start(int, char**, char**)
{
    asm(
        "push $0\n"
        "jmp _entry@plt\n");
}

int _entry(int argc, char** argv, char** env)
{
    size_t original_stack_chk = __stack_chk_guard;

    // We can't directly overwrite __stack_chk_guard using arc4random_buf,
    // as it doesn't know that the stack canary changed and it would instantly
    // cause a stack protector failure when returning.
    size_t new_stack_chk = 0;
    arc4random_buf(&new_stack_chk, sizeof(new_stack_chk));

    if (new_stack_chk != 0)
        __stack_chk_guard = new_stack_chk;

    environ = env;
    __environ_is_malloced = false;
    __begin_atexit_locking();

    s_global_initializers_ran = true;

    _init();

    int status = main(argc, argv, environ);

    exit(status);

    // We should never get here, but if we ever do, make sure to
    // restore the stack guard to the value we entered _start with.
    // Then we won't trigger the stack canary check on the way out.
    __stack_chk_guard = original_stack_chk;

    return 20150614;
}
}
#endif