mirror of
https://github.com/RGBCube/serenity
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aa9fab9c3a
The fact that we used a Vector meant that even if creating a Mount object succeeded, we were still at a risk that appending to the actual mounts Vector could fail due to OOM condition. To guard against this, the mount table is now an IntrusiveList, which always means that when allocation of a Mount object succeeded, then inserting that object to the list will succeed, which allows us to fail early in case of OOM condition.
115 lines
5.3 KiB
C++
115 lines
5.3 KiB
C++
/*
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* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Badge.h>
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#include <AK/Error.h>
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#include <AK/Function.h>
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#include <AK/HashMap.h>
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#include <AK/NonnullOwnPtrVector.h>
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#include <AK/OwnPtr.h>
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#include <AK/RefPtr.h>
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#include <Kernel/FileSystem/FileBackedFileSystem.h>
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#include <Kernel/FileSystem/FileSystem.h>
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#include <Kernel/FileSystem/InodeIdentifier.h>
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#include <Kernel/FileSystem/InodeMetadata.h>
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#include <Kernel/FileSystem/Mount.h>
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#include <Kernel/FileSystem/UnveilNode.h>
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#include <Kernel/Forward.h>
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#include <Kernel/Library/LockRefPtr.h>
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#include <Kernel/Locking/SpinlockProtected.h>
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namespace Kernel {
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// Kernel internal options.
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#define O_NOFOLLOW_NOERROR (1 << 29)
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#define O_UNLINK_INTERNAL (1 << 30)
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struct UidAndGid {
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UserID uid;
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GroupID gid;
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};
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class VirtualFileSystem {
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public:
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// Required to be at least 8 by POSIX
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// https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/limits.h.html
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static constexpr int symlink_recursion_limit = 8;
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static void initialize();
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static VirtualFileSystem& the();
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VirtualFileSystem();
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~VirtualFileSystem();
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ErrorOr<void> mount_root(FileSystem&);
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ErrorOr<void> mount(FileSystem&, Custody& mount_point, int flags);
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ErrorOr<void> bind_mount(Custody& source, Custody& mount_point, int flags);
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ErrorOr<void> remount(Custody& mount_point, int new_flags);
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ErrorOr<void> unmount(Custody& mount_point);
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ErrorOr<NonnullLockRefPtr<OpenFileDescription>> open(Credentials const&, StringView path, int options, mode_t mode, Custody& base, Optional<UidAndGid> = {});
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ErrorOr<NonnullLockRefPtr<OpenFileDescription>> create(Credentials const&, StringView path, int options, mode_t mode, Custody& parent_custody, Optional<UidAndGid> = {});
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ErrorOr<void> mkdir(Credentials const&, StringView path, mode_t mode, Custody& base);
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ErrorOr<void> link(Credentials const&, StringView old_path, StringView new_path, Custody& base);
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ErrorOr<void> unlink(Credentials const&, StringView path, Custody& base);
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ErrorOr<void> symlink(Credentials const&, StringView target, StringView linkpath, Custody& base);
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ErrorOr<void> rmdir(Credentials const&, StringView path, Custody& base);
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ErrorOr<void> chmod(Credentials const&, StringView path, mode_t, Custody& base, int options = 0);
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ErrorOr<void> chmod(Credentials const&, Custody&, mode_t);
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ErrorOr<void> chown(Credentials const&, StringView path, UserID, GroupID, Custody& base, int options);
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ErrorOr<void> chown(Credentials const&, Custody&, UserID, GroupID);
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ErrorOr<void> access(Credentials const&, StringView path, int mode, Custody& base);
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ErrorOr<InodeMetadata> lookup_metadata(Credentials const&, StringView path, Custody& base, int options = 0);
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ErrorOr<void> utime(Credentials const&, StringView path, Custody& base, time_t atime, time_t mtime);
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ErrorOr<void> utimensat(Credentials const&, StringView path, Custody& base, timespec const& atime, timespec const& mtime, int options = 0);
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ErrorOr<void> rename(Credentials const&, StringView oldpath, StringView newpath, Custody& base);
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ErrorOr<void> mknod(Credentials const&, StringView path, mode_t, dev_t, Custody& base);
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ErrorOr<NonnullRefPtr<Custody>> open_directory(Credentials const&, StringView path, Custody& base);
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ErrorOr<void> for_each_mount(Function<ErrorOr<void>(Mount const&)>) const;
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ErrorOr<NonnullLockRefPtr<FileBackedFileSystem>> find_already_existing_or_create_file_backed_file_system(OpenFileDescription& description, Function<ErrorOr<NonnullLockRefPtr<FileSystem>>(OpenFileDescription&)> callback);
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InodeIdentifier root_inode_id() const;
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void sync_filesystems();
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void lock_all_filesystems();
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static void sync();
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NonnullRefPtr<Custody> root_custody();
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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);
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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);
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private:
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friend class OpenFileDescription;
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UnveilNode const& find_matching_unveiled_path(StringView path);
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ErrorOr<void> validate_path_against_process_veil(Custody const& path, int options);
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ErrorOr<void> validate_path_against_process_veil(StringView path, int options);
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bool is_vfs_root(InodeIdentifier) const;
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ErrorOr<void> traverse_directory_inode(Inode&, Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>);
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bool mount_point_exists_at_inode(InodeIdentifier inode);
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// FIXME: These functions are totally unsafe as someone could unmount the returned Mount underneath us.
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Mount* find_mount_for_host(InodeIdentifier);
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Mount* find_mount_for_guest(InodeIdentifier);
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LockRefPtr<Inode> m_root_inode;
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SpinlockProtected<RefPtr<Custody>> m_root_custody;
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SpinlockProtected<IntrusiveList<&Mount::m_vfs_list_node>> m_mounts { LockRank::None };
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SpinlockProtected<IntrusiveList<&FileBackedFileSystem::m_file_backed_file_system_node>> m_file_backed_file_systems_list { LockRank::None };
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SpinlockProtected<IntrusiveList<&FileSystem::m_file_system_node>> m_file_systems_list { LockRank::FileSystem };
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};
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}
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