ladybird/Kernel/FileSystem/VirtualFileSystem.h
Andreas Kling c3351d4b9f Kernel: Make VirtualFileSystem functions take credentials as input
Instead of getting credentials from Process::current(), we now require
that they be provided as input to the various VFS functions.

This ensures that an atomic set of credentials is used throughout an
entire VFS operation.
2022-08-21 16:02:24 +02:00

106 lines
4.7 KiB
C++

/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Badge.h>
#include <AK/Error.h>
#include <AK/Function.h>
#include <AK/HashMap.h>
#include <AK/NonnullOwnPtrVector.h>
#include <AK/OwnPtr.h>
#include <Kernel/FileSystem/FileSystem.h>
#include <Kernel/FileSystem/InodeIdentifier.h>
#include <Kernel/FileSystem/InodeMetadata.h>
#include <Kernel/FileSystem/Mount.h>
#include <Kernel/FileSystem/UnveilNode.h>
#include <Kernel/Forward.h>
#include <Kernel/Library/LockRefPtr.h>
#include <Kernel/Locking/SpinlockProtected.h>
namespace Kernel {
// Kernel internal options.
#define O_NOFOLLOW_NOERROR (1 << 29)
#define O_UNLINK_INTERNAL (1 << 30)
struct UidAndGid {
UserID uid;
GroupID gid;
};
class VirtualFileSystem {
public:
// Required to be at least 8 by POSIX
// https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/limits.h.html
static constexpr int symlink_recursion_limit = 8;
static void initialize();
static VirtualFileSystem& the();
VirtualFileSystem();
~VirtualFileSystem();
ErrorOr<void> mount_root(FileSystem&);
ErrorOr<void> mount(FileSystem&, Custody& mount_point, int flags);
ErrorOr<void> bind_mount(Custody& source, Custody& mount_point, int flags);
ErrorOr<void> remount(Custody& mount_point, int new_flags);
ErrorOr<void> unmount(Inode& guest_inode);
ErrorOr<NonnullLockRefPtr<OpenFileDescription>> open(Credentials const&, StringView path, int options, mode_t mode, Custody& base, Optional<UidAndGid> = {});
ErrorOr<NonnullLockRefPtr<OpenFileDescription>> create(Credentials const&, StringView path, int options, mode_t mode, Custody& parent_custody, Optional<UidAndGid> = {});
ErrorOr<void> mkdir(Credentials const&, StringView path, mode_t mode, Custody& base);
ErrorOr<void> link(Credentials const&, StringView old_path, StringView new_path, Custody& base);
ErrorOr<void> unlink(Credentials const&, StringView path, Custody& base);
ErrorOr<void> symlink(Credentials const&, StringView target, StringView linkpath, Custody& base);
ErrorOr<void> rmdir(Credentials const&, StringView path, Custody& base);
ErrorOr<void> chmod(Credentials const&, StringView path, mode_t, Custody& base, int options = 0);
ErrorOr<void> chmod(Credentials const&, Custody&, mode_t);
ErrorOr<void> chown(Credentials const&, StringView path, UserID, GroupID, Custody& base, int options);
ErrorOr<void> chown(Credentials const&, Custody&, UserID, GroupID);
ErrorOr<void> access(Credentials const&, StringView path, int mode, Custody& base);
ErrorOr<InodeMetadata> lookup_metadata(Credentials const&, StringView path, Custody& base, int options = 0);
ErrorOr<void> utime(Credentials const&, StringView path, Custody& base, time_t atime, time_t mtime);
ErrorOr<void> utimensat(Credentials const&, StringView path, Custody& base, timespec const& atime, timespec const& mtime, int options = 0);
ErrorOr<void> rename(Credentials const&, StringView oldpath, StringView newpath, Custody& base);
ErrorOr<void> mknod(Credentials const&, StringView path, mode_t, dev_t, Custody& base);
ErrorOr<NonnullRefPtr<Custody>> open_directory(Credentials const&, StringView path, Custody& base);
ErrorOr<void> for_each_mount(Function<ErrorOr<void>(Mount const&)>) const;
InodeIdentifier root_inode_id() const;
static void sync();
NonnullRefPtr<Custody> root_custody();
ErrorOr<NonnullRefPtr<Custody>> resolve_path(Credentials const&, StringView path, NonnullRefPtr<Custody> base, RefPtr<Custody>* out_parent = nullptr, int options = 0, int symlink_recursion_level = 0);
ErrorOr<NonnullRefPtr<Custody>> resolve_path_without_veil(Credentials const&, StringView path, NonnullRefPtr<Custody> base, RefPtr<Custody>* out_parent = nullptr, int options = 0, int symlink_recursion_level = 0);
private:
friend class OpenFileDescription;
UnveilNode const& find_matching_unveiled_path(StringView path);
ErrorOr<void> validate_path_against_process_veil(Custody const& path, int options);
ErrorOr<void> validate_path_against_process_veil(StringView path, int options);
bool is_vfs_root(InodeIdentifier) const;
ErrorOr<void> traverse_directory_inode(Inode&, Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>);
bool mount_point_exists_at_inode(InodeIdentifier inode);
// FIXME: These functions are totally unsafe as someone could unmount the returned Mount underneath us.
Mount* find_mount_for_host(InodeIdentifier);
Mount* find_mount_for_guest(InodeIdentifier);
LockRefPtr<Inode> m_root_inode;
SpinlockProtected<RefPtr<Custody>> m_root_custody;
SpinlockProtected<Vector<NonnullOwnPtr<Mount>, 16>> m_mounts { LockRank::None };
};
}