/
ipc_namespace.go
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/
ipc_namespace.go
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// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// 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.
package kernel
import (
"fmt"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/mqfs"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/nsfs"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/kernel/mq"
"gvisor.dev/gvisor/pkg/sentry/kernel/msgqueue"
"gvisor.dev/gvisor/pkg/sentry/kernel/semaphore"
"gvisor.dev/gvisor/pkg/sentry/kernel/shm"
"gvisor.dev/gvisor/pkg/sentry/vfs"
)
// IPCNamespace represents an IPC namespace.
//
// +stateify savable
type IPCNamespace struct {
inode *nsfs.Inode
// User namespace which owns this IPC namespace. Immutable.
userNS *auth.UserNamespace
// System V utilities.
queues *msgqueue.Registry
semaphores *semaphore.Registry
shms *shm.Registry
// posixQueues is a POSIX message queue registry.
//
// posixQueues is somewhat equivalent to Linux's ipc_namespace.mq_mnt.
// Unlike SysV utilities, mq.Registry is not map-based, but is backed by
// a virtual filesystem.
posixQueues *mq.Registry
}
// NewIPCNamespace creates a new IPC namespace.
func NewIPCNamespace(userNS *auth.UserNamespace) *IPCNamespace {
ns := &IPCNamespace{
userNS: userNS,
queues: msgqueue.NewRegistry(userNS),
semaphores: semaphore.NewRegistry(userNS),
shms: shm.NewRegistry(userNS),
}
return ns
}
// Type implements nsfs.Namespace.Type.
func (i *IPCNamespace) Type() string {
return "ipc"
}
// Destroy implements nsfs.Namespace.Destroy.
func (i *IPCNamespace) Destroy(ctx context.Context) {
i.shms.Release(ctx)
if i.posixQueues != nil {
i.posixQueues.Destroy(ctx)
}
}
// SetInode sets the nsfs `inode` to the IPC namespace.
func (i *IPCNamespace) SetInode(inode *nsfs.Inode) {
i.inode = inode
}
// GetInode returns the nsfs inode associated with the IPC namespace.
func (i *IPCNamespace) GetInode() *nsfs.Inode {
return i.inode
}
// UserNamespace returns the user namespace associated with the namespace.
func (i *IPCNamespace) UserNamespace() *auth.UserNamespace {
return i.userNS
}
// MsgqueueRegistry returns the message queue registry for this namespace.
func (i *IPCNamespace) MsgqueueRegistry() *msgqueue.Registry {
return i.queues
}
// SemaphoreRegistry returns the semaphore set registry for this namespace.
func (i *IPCNamespace) SemaphoreRegistry() *semaphore.Registry {
return i.semaphores
}
// ShmRegistry returns the shm segment registry for this namespace.
func (i *IPCNamespace) ShmRegistry() *shm.Registry {
return i.shms
}
// InitPosixQueues creates a new POSIX queue registry, and returns an error if
// the registry was previously initialized.
func (i *IPCNamespace) InitPosixQueues(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials) error {
if i.posixQueues != nil {
return fmt.Errorf("IPCNamespace.InitPosixQueues: already initialized")
}
impl, err := mqfs.NewRegistryImpl(ctx, vfsObj, creds)
if err != nil {
return err
}
i.posixQueues = mq.NewRegistry(i.userNS, impl)
return nil
}
// PosixQueues returns the posix message queue registry for this namespace.
//
// Precondition: i.InitPosixQueues must have been called.
func (i *IPCNamespace) PosixQueues() *mq.Registry {
return i.posixQueues
}
// IncRef increments the Namespace's refcount.
func (i *IPCNamespace) IncRef() {
i.inode.IncRef()
}
// DecRef decrements the namespace's refcount.
func (i *IPCNamespace) DecRef(ctx context.Context) {
i.inode.DecRef(ctx)
}
// IPCNamespace returns the task's IPC namespace.
func (t *Task) IPCNamespace() *IPCNamespace {
t.mu.Lock()
defer t.mu.Unlock()
return t.ipcns
}
// GetIPCNamespace takes a reference on the task IPC namespace and
// returns it. It will return nil if the task isn't alive.
func (t *Task) GetIPCNamespace() *IPCNamespace {
t.mu.Lock()
defer t.mu.Unlock()
if t.ipcns != nil {
t.ipcns.IncRef()
}
return t.ipcns
}