ladybird/Kernel/Syscalls/readlink.cpp
2021-08-01 08:10:16 +02:00

47 lines
1.3 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/StringView.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/Process.h>
namespace Kernel {
KResultOr<FlatPtr> Process::sys$readlink(Userspace<const Syscall::SC_readlink_params*> user_params)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(rpath);
Syscall::SC_readlink_params params;
if (!copy_from_user(&params, user_params))
return EFAULT;
auto path = get_syscall_path_argument(params.path);
if (path.is_error())
return path.error();
auto result = VirtualFileSystem::the().open(path.value()->view(), O_RDONLY | O_NOFOLLOW_NOERROR, 0, current_directory());
if (result.is_error())
return result.error();
auto description = result.value();
if (!description->metadata().is_symlink())
return EINVAL;
auto contents = description->read_entire_file();
if (contents.is_error())
return contents.error();
auto& link_target = *contents.value();
auto size_to_copy = min(link_target.size(), params.buffer.size);
if (!copy_to_user(params.buffer.data, link_target.data(), size_to_copy))
return EFAULT;
// Note: we return the whole size here, not the copied size.
return link_target.size();
}
}