mirror of
https://github.com/SerenityOS/serenity
synced 2024-09-06 17:06:31 +00:00
38 lines
1.4 KiB
C++
38 lines
1.4 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/Tasks/Process.h>
|
|
|
|
namespace Kernel {
|
|
|
|
ErrorOr<FlatPtr> Process::sys$readlink(Userspace<Syscall::SC_readlink_params const*> user_params)
|
|
{
|
|
VERIFY_NO_PROCESS_BIG_LOCK(this);
|
|
TRY(require_promise(Pledge::rpath));
|
|
auto params = TRY(copy_typed_from_user(user_params));
|
|
|
|
auto path = TRY(get_syscall_path_argument(params.path));
|
|
auto description = TRY(VirtualFileSystem::the().open(credentials(), path->view(), O_RDONLY | O_NOFOLLOW_NOERROR, 0, TRY(custody_for_dirfd(params.dirfd))));
|
|
|
|
if (!description->metadata().is_symlink())
|
|
return EINVAL;
|
|
|
|
// Make sure that our assumptions about the path length hold up.
|
|
// Note that this doesn't mean that the reported size can be trusted, some inodes just report zero.
|
|
VERIFY(description->inode()->size() <= MAXPATHLEN);
|
|
|
|
Array<u8, MAXPATHLEN> link_target;
|
|
auto read_bytes = TRY(description->inode()->read_until_filled_or_end(0, link_target.size(), UserOrKernelBuffer::for_kernel_buffer(link_target.data()), description));
|
|
auto size_to_copy = min(read_bytes, params.buffer.size);
|
|
TRY(copy_to_user(params.buffer.data, link_target.data(), size_to_copy));
|
|
// Note: we return the whole size here, not the copied size.
|
|
return read_bytes;
|
|
}
|
|
|
|
}
|