Kernel/Syscalls/get_stack_bounds.cpp


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

#include <Kernel/Memory/Region.h>
#include <Kernel/Process.h>

namespace Kernel {

KResultOr<FlatPtr> Process::sys$get_stack_bounds(Userspace<FlatPtr*> user_stack_base, Userspace<size_t*> user_stack_size)
{
    VERIFY_NO_PROCESS_BIG_LOCK(this);
    auto& regs = Thread::current()->get_register_dump_from_stack();
    FlatPtr stack_pointer = regs.userspace_sp();
    auto* stack_region = address_space().find_region_containing(Memory::VirtualRange { 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;
}

}