mirror of
https://github.com/netbirdio/gvisor.git
synced 2026-05-22 17:12:49 -07:00
Andrei Vagin
5f4abad306
It is an idea of running codespell as part of our presubmit checks. Before enabling it for new changes, let's fix what it has found. Signed-off-by: Andrei Vagin <avagin@gmail.com>
110 lines
3.5 KiB
Go
110 lines
3.5 KiB
Go
// Copyright 2021 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 mqfs provides a filesystem implementation to back POSIX message
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// queues.
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package mqfs
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import (
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"fmt"
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"gvisor.dev/gvisor/pkg/context"
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"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
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"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
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"gvisor.dev/gvisor/pkg/sentry/kernel/ipc"
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"gvisor.dev/gvisor/pkg/sentry/kernel/mq"
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"gvisor.dev/gvisor/pkg/sentry/vfs"
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)
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const (
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// Name is the user-visible filesystem name.
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Name = "mqueue"
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)
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// FilesystemType implements vfs.FilesystemType.
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//
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// +stateify savable
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type FilesystemType struct{}
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// Name implements vfs.FilesystemType.Name.
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func (FilesystemType) Name() string {
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return Name
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}
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// Release implements vfs.FilesystemType.Release.
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func (FilesystemType) Release(ctx context.Context) {}
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// GetFilesystem implements vfs.FilesystemType.GetFilesystem.
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func (ft FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, source string, opts vfs.GetFilesystemOptions) (*vfs.Filesystem, *vfs.Dentry, error) {
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// mqfs is initialized only once per ipc namespace. Each ipc namespace has
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// a POSIX message registry with a root dentry, filesystem, and a
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// disconnected mount. We want the fs to be consistent for all processes in
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// the same ipc namespace, so instead of creating a new fs and root dentry,
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// we retrieve them using IPCNamespace.PosixQueues and use them.
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i := ipcNamespaceFromContext(ctx)
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if i == nil {
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return nil, nil, fmt.Errorf("mqfs.FilesystemType.GetFilesystem: ipc namespace doesn't exist")
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}
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defer i.DecRef(ctx)
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registry := i.PosixQueues()
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if registry == nil {
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return nil, nil, fmt.Errorf("mqfs.FilesystemType.GetFilesystem: ipc namespace doesn't have a POSIX registry")
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}
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impl := registry.Impl().(*RegistryImpl)
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impl.fs.VFSFilesystem().IncRef()
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impl.root.IncRef()
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return impl.fs.VFSFilesystem(), impl.root.VFSDentry(), nil
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}
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// filesystem implements kernfs.Filesystem.
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//
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// +stateify savable
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type filesystem struct {
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kernfs.Filesystem
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devMinor uint32
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}
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// Release implements vfs.FilesystemImpl.Release.
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func (fs *filesystem) Release(ctx context.Context) {
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fs.Filesystem.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor)
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fs.Filesystem.Release(ctx)
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}
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// MountOptions implements vfs.FilesystemImpl.MountOptions.
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func (fs *filesystem) MountOptions() string {
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return ""
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}
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// ipcNamespace defines functions we need from kernel.IPCNamespace. We redefine
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// ipcNamespace along with ipcNamespaceFromContext to avoid circular dependency
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// with package sentry/kernel.
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type ipcNamespace interface {
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// PosixQueues returns a POSIX message queue registry.
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PosixQueues() *mq.Registry
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// DecRef decrements ipcNamespace's number of references.
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DecRef(ctx context.Context)
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}
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// ipcNamespaceFromContext returns the IPC namespace in which ctx is executing.
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// Copied from package sentry/kernel.
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func ipcNamespaceFromContext(ctx context.Context) ipcNamespace {
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if v := ctx.Value(ipc.CtxIPCNamespace); v != nil {
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return v.(ipcNamespace)
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}
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return nil
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}
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