mirror of
https://github.com/netbirdio/gvisor.git
synced 2026-05-22 17:12:49 -07:00
Implement an anon_inode equivalent for VFS2.
PiperOrigin-RevId: 291986033
This commit is contained in:
Jamie Liu
gVisor bot
@@ -5,6 +5,7 @@ licenses(["notice"])
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go_library(
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name = "vfs",
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srcs = [
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"anonfs.go",
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"context.go",
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"debug.go",
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"dentry.go",
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@@ -20,7 +21,6 @@ go_library(
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"pathname.go",
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"permissions.go",
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"resolving_path.go",
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"testutil.go",
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"vfs.go",
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],
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visibility = ["//pkg/sentry:internal"],
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@@ -50,7 +50,6 @@ go_test(
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"//pkg/abi/linux",
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"//pkg/context",
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"//pkg/sentry/contexttest",
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"//pkg/sentry/kernel/auth",
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"//pkg/sync",
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"//pkg/syserror",
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"//pkg/usermem",
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@@ -0,0 +1,259 @@
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// Copyright 2020 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package vfs
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import (
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"fmt"
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"gvisor.dev/gvisor/pkg/abi/linux"
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"gvisor.dev/gvisor/pkg/context"
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"gvisor.dev/gvisor/pkg/fspath"
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"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
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"gvisor.dev/gvisor/pkg/syserror"
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"gvisor.dev/gvisor/pkg/usermem"
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)
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// NewAnonVirtualDentry returns a VirtualDentry with the given synthetic name,
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// consistent with Linux's fs/anon_inodes.c:anon_inode_getfile(). References
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// are taken on the returned VirtualDentry.
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func (vfs *VirtualFilesystem) NewAnonVirtualDentry(name string) VirtualDentry {
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d := anonDentry{
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name: name,
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}
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d.vfsd.Init(&d)
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vfs.anonMount.IncRef()
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// anonDentry no-ops refcounting.
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return VirtualDentry{
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mount: vfs.anonMount,
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dentry: &d.vfsd,
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}
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}
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const anonfsBlockSize = usermem.PageSize // via fs/libfs.c:pseudo_fs_fill_super()
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// anonFilesystem is the implementation of FilesystemImpl that backs
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// VirtualDentries returned by VirtualFilesystem.NewAnonVirtualDentry().
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//
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// Since all Dentries in anonFilesystem are non-directories, all FilesystemImpl
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// methods that would require an anonDentry to be a directory return ENOTDIR.
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type anonFilesystem struct {
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vfsfs Filesystem
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devMinor uint32
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}
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type anonDentry struct {
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vfsd Dentry
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name string
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}
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// Release implements FilesystemImpl.Release.
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func (fs *anonFilesystem) Release() {
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}
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// Sync implements FilesystemImpl.Sync.
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func (fs *anonFilesystem) Sync(ctx context.Context) error {
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return nil
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}
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// GetDentryAt implements FilesystemImpl.GetDentryAt.
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func (fs *anonFilesystem) GetDentryAt(ctx context.Context, rp *ResolvingPath, opts GetDentryOptions) (*Dentry, error) {
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if !rp.Done() {
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return nil, syserror.ENOTDIR
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}
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if opts.CheckSearchable {
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return nil, syserror.ENOTDIR
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}
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// anonDentry no-ops refcounting.
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return rp.Start(), nil
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}
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// GetParentDentryAt implements FilesystemImpl.GetParentDentryAt.
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func (fs *anonFilesystem) GetParentDentryAt(ctx context.Context, rp *ResolvingPath) (*Dentry, error) {
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if !rp.Final() {
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return nil, syserror.ENOTDIR
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}
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// anonDentry no-ops refcounting.
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return rp.Start(), nil
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}
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// LinkAt implements FilesystemImpl.LinkAt.
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func (fs *anonFilesystem) LinkAt(ctx context.Context, rp *ResolvingPath, vd VirtualDentry) error {
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if !rp.Final() {
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return syserror.ENOTDIR
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}
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return syserror.EPERM
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}
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// MkdirAt implements FilesystemImpl.MkdirAt.
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func (fs *anonFilesystem) MkdirAt(ctx context.Context, rp *ResolvingPath, opts MkdirOptions) error {
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if !rp.Final() {
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return syserror.ENOTDIR
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}
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return syserror.EPERM
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}
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// MknodAt implements FilesystemImpl.MknodAt.
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func (fs *anonFilesystem) MknodAt(ctx context.Context, rp *ResolvingPath, opts MknodOptions) error {
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if !rp.Final() {
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return syserror.ENOTDIR
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}
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return syserror.EPERM
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}
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// OpenAt implements FilesystemImpl.OpenAt.
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func (fs *anonFilesystem) OpenAt(ctx context.Context, rp *ResolvingPath, opts OpenOptions) (*FileDescription, error) {
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if !rp.Done() {
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return nil, syserror.ENOTDIR
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}
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return nil, syserror.ENODEV
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}
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// ReadlinkAt implements FilesystemImpl.ReadlinkAt.
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func (fs *anonFilesystem) ReadlinkAt(ctx context.Context, rp *ResolvingPath) (string, error) {
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if !rp.Done() {
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return "", syserror.ENOTDIR
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}
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return "", syserror.EINVAL
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}
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// RenameAt implements FilesystemImpl.RenameAt.
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func (fs *anonFilesystem) RenameAt(ctx context.Context, rp *ResolvingPath, oldParentVD VirtualDentry, oldName string, opts RenameOptions) error {
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if !rp.Final() {
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return syserror.ENOTDIR
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}
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return syserror.EPERM
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}
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// RmdirAt implements FilesystemImpl.RmdirAt.
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func (fs *anonFilesystem) RmdirAt(ctx context.Context, rp *ResolvingPath) error {
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if !rp.Final() {
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return syserror.ENOTDIR
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}
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return syserror.EPERM
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}
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// SetStatAt implements FilesystemImpl.SetStatAt.
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func (fs *anonFilesystem) SetStatAt(ctx context.Context, rp *ResolvingPath, opts SetStatOptions) error {
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if !rp.Done() {
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return syserror.ENOTDIR
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}
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// Linux actually permits anon_inode_inode's metadata to be set, which is
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// visible to all users of anon_inode_inode. We just silently ignore
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// metadata changes.
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return nil
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}
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// StatAt implements FilesystemImpl.StatAt.
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func (fs *anonFilesystem) StatAt(ctx context.Context, rp *ResolvingPath, opts StatOptions) (linux.Statx, error) {
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if !rp.Done() {
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return linux.Statx{}, syserror.ENOTDIR
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}
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// See fs/anon_inodes.c:anon_inode_init() => fs/libfs.c:alloc_anon_inode().
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return linux.Statx{
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Mask: linux.STATX_TYPE | linux.STATX_MODE | linux.STATX_NLINK | linux.STATX_UID | linux.STATX_GID | linux.STATX_INO | linux.STATX_SIZE | linux.STATX_BLOCKS,
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Blksize: anonfsBlockSize,
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Nlink: 1,
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UID: uint32(auth.RootKUID),
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GID: uint32(auth.RootKGID),
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Mode: 0600, // no type is correct
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Ino: 1,
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Size: 0,
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Blocks: 0,
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DevMajor: 0,
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DevMinor: fs.devMinor,
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}, nil
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}
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// StatFSAt implements FilesystemImpl.StatFSAt.
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func (fs *anonFilesystem) StatFSAt(ctx context.Context, rp *ResolvingPath) (linux.Statfs, error) {
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if !rp.Done() {
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return linux.Statfs{}, syserror.ENOTDIR
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}
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return linux.Statfs{
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Type: linux.ANON_INODE_FS_MAGIC,
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BlockSize: anonfsBlockSize,
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}, nil
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}
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// SymlinkAt implements FilesystemImpl.SymlinkAt.
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func (fs *anonFilesystem) SymlinkAt(ctx context.Context, rp *ResolvingPath, target string) error {
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if !rp.Final() {
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return syserror.ENOTDIR
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}
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return syserror.EPERM
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}
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// UnlinkAt implements FilesystemImpl.UnlinkAt.
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func (fs *anonFilesystem) UnlinkAt(ctx context.Context, rp *ResolvingPath) error {
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if !rp.Final() {
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return syserror.ENOTDIR
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}
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return syserror.EPERM
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}
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// ListxattrAt implements FilesystemImpl.ListxattrAt.
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func (fs *anonFilesystem) ListxattrAt(ctx context.Context, rp *ResolvingPath) ([]string, error) {
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if !rp.Done() {
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return nil, syserror.ENOTDIR
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}
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return nil, nil
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}
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// GetxattrAt implements FilesystemImpl.GetxattrAt.
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func (fs *anonFilesystem) GetxattrAt(ctx context.Context, rp *ResolvingPath, name string) (string, error) {
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if !rp.Done() {
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return "", syserror.ENOTDIR
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}
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return "", syserror.ENOTSUP
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}
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// SetxattrAt implements FilesystemImpl.SetxattrAt.
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func (fs *anonFilesystem) SetxattrAt(ctx context.Context, rp *ResolvingPath, opts SetxattrOptions) error {
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if !rp.Done() {
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return syserror.ENOTDIR
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}
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return syserror.EPERM
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}
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// RemovexattrAt implements FilesystemImpl.RemovexattrAt.
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func (fs *anonFilesystem) RemovexattrAt(ctx context.Context, rp *ResolvingPath, name string) error {
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if !rp.Done() {
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return syserror.ENOTDIR
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}
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return syserror.EPERM
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}
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// PrependPath implements FilesystemImpl.PrependPath.
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func (fs *anonFilesystem) PrependPath(ctx context.Context, vfsroot, vd VirtualDentry, b *fspath.Builder) error {
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b.PrependComponent(fmt.Sprintf("anon_inode:%s", vd.dentry.impl.(*anonDentry).name))
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return PrependPathSyntheticError{}
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}
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// IncRef implements DentryImpl.IncRef.
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func (d *anonDentry) IncRef() {
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// no-op
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}
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// TryIncRef implements DentryImpl.TryIncRef.
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func (d *anonDentry) TryIncRef() bool {
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return true
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}
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// DecRef implements DentryImpl.DecRef.
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func (d *anonDentry) DecRef() {
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// no-op
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}
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@@ -24,7 +24,6 @@ import (
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"gvisor.dev/gvisor/pkg/abi/linux"
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"gvisor.dev/gvisor/pkg/context"
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"gvisor.dev/gvisor/pkg/sentry/contexttest"
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"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
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"gvisor.dev/gvisor/pkg/syserror"
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"gvisor.dev/gvisor/pkg/usermem"
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)
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@@ -46,9 +45,11 @@ type genCountFD struct {
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count uint64 // accessed using atomic memory ops
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}
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func newGenCountFD(mnt *Mount, vfsd *Dentry) *FileDescription {
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func newGenCountFD(vfsObj *VirtualFilesystem) *FileDescription {
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vd := vfsObj.NewAnonVirtualDentry("genCountFD")
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defer vd.DecRef()
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var fd genCountFD
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fd.vfsfd.Init(&fd, 0 /* statusFlags */, mnt, vfsd, &FileDescriptionOptions{})
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fd.vfsfd.Init(&fd, 0 /* statusFlags */, vd.Mount(), vd.Dentry(), &FileDescriptionOptions{})
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fd.DynamicBytesFileDescriptionImpl.SetDataSource(&fd)
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return &fd.vfsfd
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}
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@@ -86,18 +87,9 @@ func (fd *genCountFD) Generate(ctx context.Context, buf *bytes.Buffer) error {
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func TestGenCountFD(t *testing.T) {
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ctx := contexttest.Context(t)
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creds := auth.CredentialsFromContext(ctx)
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vfsObj := New() // vfs.New()
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vfsObj.MustRegisterFilesystemType("testfs", FDTestFilesystemType{}, &RegisterFilesystemTypeOptions{})
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mntns, err := vfsObj.NewMountNamespace(ctx, creds, "", "testfs", &GetFilesystemOptions{})
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if err != nil {
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t.Fatalf("failed to create testfs root mount: %v", err)
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}
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vd := mntns.Root()
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defer vd.DecRef()
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fd := newGenCountFD(vd.Mount(), vd.Dentry())
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fd := newGenCountFD(vfsObj)
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defer fd.DecRef()
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// The first read causes Generate to be called to fill the FD's buffer.
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@@ -1,173 +0,0 @@
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// Copyright 2019 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
|
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// you may not use this file except in compliance with the License.
|
||||
// You may obtain a copy of the License at
|
||||
//
|
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// http://www.apache.org/licenses/LICENSE-2.0
|
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//
|
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// Unless required by applicable law or agreed to in writing, software
|
||||
// distributed under the License is distributed on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
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package vfs
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import (
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"fmt"
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"gvisor.dev/gvisor/pkg/abi/linux"
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"gvisor.dev/gvisor/pkg/context"
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"gvisor.dev/gvisor/pkg/fspath"
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"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
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"gvisor.dev/gvisor/pkg/syserror"
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)
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// FDTestFilesystemType is a test-only FilesystemType that produces Filesystems
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// for which all FilesystemImpl methods taking a path return EPERM. It is used
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// to produce Mounts and Dentries for testing of FileDescriptionImpls that do
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// not depend on their originating Filesystem.
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type FDTestFilesystemType struct{}
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// FDTestFilesystem is a test-only FilesystemImpl produced by
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// FDTestFilesystemType.
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type FDTestFilesystem struct {
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vfsfs Filesystem
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}
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// GetFilesystem implements FilesystemType.GetFilesystem.
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func (fstype FDTestFilesystemType) GetFilesystem(ctx context.Context, vfsObj *VirtualFilesystem, creds *auth.Credentials, source string, opts GetFilesystemOptions) (*Filesystem, *Dentry, error) {
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var fs FDTestFilesystem
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fs.vfsfs.Init(vfsObj, &fs)
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return &fs.vfsfs, fs.NewDentry(), nil
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}
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// Release implements FilesystemImpl.Release.
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func (fs *FDTestFilesystem) Release() {
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}
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// Sync implements FilesystemImpl.Sync.
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func (fs *FDTestFilesystem) Sync(ctx context.Context) error {
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return nil
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}
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// GetDentryAt implements FilesystemImpl.GetDentryAt.
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func (fs *FDTestFilesystem) GetDentryAt(ctx context.Context, rp *ResolvingPath, opts GetDentryOptions) (*Dentry, error) {
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return nil, syserror.EPERM
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}
|
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// GetParentDentryAt implements FilesystemImpl.GetParentDentryAt.
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func (fs *FDTestFilesystem) GetParentDentryAt(ctx context.Context, rp *ResolvingPath) (*Dentry, error) {
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return nil, syserror.EPERM
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}
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// LinkAt implements FilesystemImpl.LinkAt.
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func (fs *FDTestFilesystem) LinkAt(ctx context.Context, rp *ResolvingPath, vd VirtualDentry) error {
|
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return syserror.EPERM
|
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}
|
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|
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// MkdirAt implements FilesystemImpl.MkdirAt.
|
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func (fs *FDTestFilesystem) MkdirAt(ctx context.Context, rp *ResolvingPath, opts MkdirOptions) error {
|
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return syserror.EPERM
|
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}
|
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|
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// MknodAt implements FilesystemImpl.MknodAt.
|
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func (fs *FDTestFilesystem) MknodAt(ctx context.Context, rp *ResolvingPath, opts MknodOptions) error {
|
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return syserror.EPERM
|
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}
|
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|
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// OpenAt implements FilesystemImpl.OpenAt.
|
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func (fs *FDTestFilesystem) OpenAt(ctx context.Context, rp *ResolvingPath, opts OpenOptions) (*FileDescription, error) {
|
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return nil, syserror.EPERM
|
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}
|
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|
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// ReadlinkAt implements FilesystemImpl.ReadlinkAt.
|
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func (fs *FDTestFilesystem) ReadlinkAt(ctx context.Context, rp *ResolvingPath) (string, error) {
|
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return "", syserror.EPERM
|
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}
|
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|
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// RenameAt implements FilesystemImpl.RenameAt.
|
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func (fs *FDTestFilesystem) RenameAt(ctx context.Context, rp *ResolvingPath, oldParentVD VirtualDentry, oldName string, opts RenameOptions) error {
|
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return syserror.EPERM
|
||||
}
|
||||
|
||||
// RmdirAt implements FilesystemImpl.RmdirAt.
|
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func (fs *FDTestFilesystem) RmdirAt(ctx context.Context, rp *ResolvingPath) error {
|
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return syserror.EPERM
|
||||
}
|
||||
|
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// SetStatAt implements FilesystemImpl.SetStatAt.
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func (fs *FDTestFilesystem) SetStatAt(ctx context.Context, rp *ResolvingPath, opts SetStatOptions) error {
|
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return syserror.EPERM
|
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}
|
||||
|
||||
// StatAt implements FilesystemImpl.StatAt.
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func (fs *FDTestFilesystem) StatAt(ctx context.Context, rp *ResolvingPath, opts StatOptions) (linux.Statx, error) {
|
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return linux.Statx{}, syserror.EPERM
|
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}
|
||||
|
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// StatFSAt implements FilesystemImpl.StatFSAt.
|
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func (fs *FDTestFilesystem) StatFSAt(ctx context.Context, rp *ResolvingPath) (linux.Statfs, error) {
|
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return linux.Statfs{}, syserror.EPERM
|
||||
}
|
||||
|
||||
// SymlinkAt implements FilesystemImpl.SymlinkAt.
|
||||
func (fs *FDTestFilesystem) SymlinkAt(ctx context.Context, rp *ResolvingPath, target string) error {
|
||||
return syserror.EPERM
|
||||
}
|
||||
|
||||
// UnlinkAt implements FilesystemImpl.UnlinkAt.
|
||||
func (fs *FDTestFilesystem) UnlinkAt(ctx context.Context, rp *ResolvingPath) error {
|
||||
return syserror.EPERM
|
||||
}
|
||||
|
||||
// ListxattrAt implements FilesystemImpl.ListxattrAt.
|
||||
func (fs *FDTestFilesystem) ListxattrAt(ctx context.Context, rp *ResolvingPath) ([]string, error) {
|
||||
return nil, syserror.EPERM
|
||||
}
|
||||
|
||||
// GetxattrAt implements FilesystemImpl.GetxattrAt.
|
||||
func (fs *FDTestFilesystem) GetxattrAt(ctx context.Context, rp *ResolvingPath, name string) (string, error) {
|
||||
return "", syserror.EPERM
|
||||
}
|
||||
|
||||
// SetxattrAt implements FilesystemImpl.SetxattrAt.
|
||||
func (fs *FDTestFilesystem) SetxattrAt(ctx context.Context, rp *ResolvingPath, opts SetxattrOptions) error {
|
||||
return syserror.EPERM
|
||||
}
|
||||
|
||||
// RemovexattrAt implements FilesystemImpl.RemovexattrAt.
|
||||
func (fs *FDTestFilesystem) RemovexattrAt(ctx context.Context, rp *ResolvingPath, name string) error {
|
||||
return syserror.EPERM
|
||||
}
|
||||
|
||||
// PrependPath implements FilesystemImpl.PrependPath.
|
||||
func (fs *FDTestFilesystem) PrependPath(ctx context.Context, vfsroot, vd VirtualDentry, b *fspath.Builder) error {
|
||||
b.PrependComponent(fmt.Sprintf("vfs.fdTestDentry:%p", vd.dentry.impl.(*fdTestDentry)))
|
||||
return PrependPathSyntheticError{}
|
||||
}
|
||||
|
||||
type fdTestDentry struct {
|
||||
vfsd Dentry
|
||||
}
|
||||
|
||||
// NewDentry returns a new Dentry.
|
||||
func (fs *FDTestFilesystem) NewDentry() *Dentry {
|
||||
var d fdTestDentry
|
||||
d.vfsd.Init(&d)
|
||||
return &d.vfsd
|
||||
}
|
||||
|
||||
// IncRef implements DentryImpl.IncRef.
|
||||
func (d *fdTestDentry) IncRef() {
|
||||
}
|
||||
|
||||
// TryIncRef implements DentryImpl.TryIncRef.
|
||||
func (d *fdTestDentry) TryIncRef() bool {
|
||||
return true
|
||||
}
|
||||
|
||||
// DecRef implements DentryImpl.DecRef.
|
||||
func (d *fdTestDentry) DecRef() {
|
||||
}
|
||||
@@ -75,6 +75,14 @@ type VirtualFilesystem struct {
|
||||
// mountpoints is analogous to Linux's mountpoint_hashtable.
|
||||
mountpoints map[*Dentry]map[*Mount]struct{}
|
||||
|
||||
// anonMount is a Mount, not included in mounts or mountpoints,
|
||||
// representing an anonFilesystem. anonMount is used to back
|
||||
// VirtualDentries returned by VirtualFilesystem.NewAnonVirtualDentry().
|
||||
// anonMount is immutable.
|
||||
//
|
||||
// anonMount is analogous to Linux's anon_inode_mnt.
|
||||
anonMount *Mount
|
||||
|
||||
// devices contains all registered Devices. devices is protected by
|
||||
// devicesMu.
|
||||
devicesMu sync.RWMutex
|
||||
@@ -110,6 +118,22 @@ func New() *VirtualFilesystem {
|
||||
filesystems: make(map[*Filesystem]struct{}),
|
||||
}
|
||||
vfs.mounts.Init()
|
||||
|
||||
// Construct vfs.anonMount.
|
||||
anonfsDevMinor, err := vfs.GetAnonBlockDevMinor()
|
||||
if err != nil {
|
||||
panic(fmt.Sprintf("VirtualFilesystem.GetAnonBlockDevMinor() failed during VirtualFilesystem construction: %v", err))
|
||||
}
|
||||
anonfs := anonFilesystem{
|
||||
devMinor: anonfsDevMinor,
|
||||
}
|
||||
anonfs.vfsfs.Init(vfs, &anonfs)
|
||||
vfs.anonMount = &Mount{
|
||||
vfs: vfs,
|
||||
fs: &anonfs.vfsfs,
|
||||
refs: 1,
|
||||
}
|
||||
|
||||
return vfs
|
||||
}
|
||||
|
||||
|
||||
Reference in New Issue
Block a user