ladybird/Kernel/Syscalls/get_stack_bounds.cpp

/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <Kernel/Process.h>
#include <Kernel/VM/MemoryManager.h>

namespace Kernel {

int Process::sys$get_stack_bounds(FlatPtr* user_stack_base, size_t* user_stack_size)
{
    if (!validate_write_typed(user_stack_base))
        return -EFAULT;
    if (!validate_write_typed(user_stack_size))
        return -EFAULT;

    FlatPtr stack_pointer = Thread::current()->get_register_dump_from_stack().userspace_esp;
    auto* stack_region = MM.find_region_from_vaddr(*this, VirtualAddress(stack_pointer));
    if (!stack_region) {
        ASSERT_NOT_REACHED();
        return -EINVAL;
    }

    FlatPtr stack_base = stack_region->range().base().get();
    size_t stack_size = stack_region->size();
    copy_to_user(user_stack_base, &stack_base);
    copy_to_user(user_stack_size, &stack_size);
    return 0;
}

}