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// Copyright 2018 Google Inc.
//
// 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 (
"gvisor.googlesource.com/gvisor/pkg/abi/linux"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
)
// TaskResources is the subset of a task's data provided by its creator that is
// not provided by the loader.
type TaskResources struct {
// SignalMask is the set of signals whose delivery is currently blocked.
//
// FIXME: Determine if we also need RealSignalMask
SignalMask linux.SignalSet
// FSContext is the filesystem context.
*FSContext
// FDMap provides access to files to the task.
*FDMap
// Tracks abstract sockets that are in use.
AbstractSockets *AbstractSocketNamespace
}
// newTaskResources returns a new TaskResources, taking an additional reference
// on fdm.
func newTaskResources(fdm *FDMap, fc *FSContext) *TaskResources {
fdm.IncRef()
return &TaskResources{
FDMap: fdm,
FSContext: fc,
AbstractSockets: NewAbstractSocketNamespace(),
}
}
// release releases all resources held by the TaskResources. release is called
// by the task when it exits.
func (tr *TaskResources) release() {
tr.FDMap.DecRef()
tr.FDMap = nil
tr.FSContext.DecRef()
tr.FSContext = nil
tr.AbstractSockets = nil
}
// Fork returns a duplicate of tr.
//
// FIXME: Preconditions: When tr is owned by a Task, that task's
// signal mutex must be locked, or Fork must be called by the task's goroutine.
func (tr *TaskResources) Fork(shareFiles bool, shareFSContext bool) *TaskResources {
var fdmap *FDMap
if shareFiles {
fdmap = tr.FDMap
fdmap.IncRef()
} else {
fdmap = tr.FDMap.Fork()
}
var fsc *FSContext
if shareFSContext {
fsc = tr.FSContext
fsc.IncRef()
} else {
fsc = tr.FSContext.Fork()
}
return &TaskResources{
SignalMask: tr.SignalMask,
FDMap: fdmap,
FSContext: fsc,
AbstractSockets: tr.AbstractSockets,
}
}
// FDMap returns t's FDMap.
//
// Preconditions: The caller must be running on the task goroutine, or t.mu
// must be locked.
func (t *Task) FDMap() *FDMap {
return t.tr.FDMap
}
// FSContext returns t's FSContext.
//
// Preconditions: The caller must be running on the task goroutine, or t.mu
// must be locked.
func (t *Task) FSContext() *FSContext {
return t.tr.FSContext
}
// MountNamespace returns t's MountNamespace. MountNamespace does not take an additional
// reference on the returned MountNamespace.
func (t *Task) MountNamespace() *fs.MountNamespace {
return t.k.mounts
}
// AbstractSockets returns t's AbstractSocketNamespace.
func (t *Task) AbstractSockets() *AbstractSocketNamespace {
return t.tr.AbstractSockets
}
// IsChrooted returns true if the root directory of t's FSContext is not the
// root directory of t's MountNamespace.
//
// Preconditions: The caller must be running on the task goroutine, or t.mu
// must be locked.
func (t *Task) IsChrooted() bool {
realRoot := t.k.mounts.Root()
defer realRoot.DecRef()
root := t.tr.FSContext.RootDirectory()
defer root.DecRef()
return root != realRoot
}
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