ladybird/Kernel/Syscalls/chdir.cpp

62 lines
2.0 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/RefPtr.h>
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/Tasks/Process.h>
namespace Kernel {
ErrorOr<FlatPtr> Process::sys$chdir(Userspace<char const*> user_path, size_t path_length)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::rpath));
auto path = TRY(get_syscall_path_argument(user_path, path_length));
auto current_directory = m_current_directory.with([](auto& current_directory) -> NonnullRefPtr<Custody> {
return *current_directory;
});
RefPtr<Custody> new_directory = TRY(VirtualFileSystem::the().open_directory(credentials(), path->view(), *current_directory));
m_current_directory.with([&](auto& current_directory) {
// NOTE: We use swap() here to avoid manipulating the ref counts while holding the lock.
swap(current_directory, new_directory);
});
return 0;
}
ErrorOr<FlatPtr> Process::sys$fchdir(int fd)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::stdio));
auto description = TRY(open_file_description(fd));
if (!description->is_directory())
return ENOTDIR;
if (!description->metadata().may_execute(credentials()))
return EACCES;
m_current_directory.with([&](auto& current_directory) {
current_directory = description->custody();
});
return 0;
}
ErrorOr<FlatPtr> Process::sys$getcwd(Userspace<char*> buffer, size_t size)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::rpath));
if (size > NumericLimits<ssize_t>::max())
return EINVAL;
auto path = TRY(current_directory()->try_serialize_absolute_path());
size_t ideal_size = path->length() + 1;
auto size_to_copy = min(ideal_size, size);
TRY(copy_to_user(buffer, path->characters(), size_to_copy));
// Note: we return the whole size here, not the copied size.
return ideal_size;
}
}