Kernel/Syscalls/get_stack_bounds.cpp


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30

/*
 * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <Kernel/Panic.h>
#include <Kernel/Process.h>
#include <Kernel/VM/Region.h>

namespace Kernel {

KResultOr<int> Process::sys$get_stack_bounds(Userspace<FlatPtr*> user_stack_base, Userspace<size_t*> user_stack_size)
{
    FlatPtr stack_pointer = Thread::current()->get_register_dump_from_stack().userspace_esp;
    auto* stack_region = space().find_region_containing(Range { VirtualAddress(stack_pointer), 1 });

    // The syscall handler should have killed us if we had an invalid stack pointer.
    VERIFY(stack_region);

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

}