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// Copyright 2019 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 testutil
import (
"flag"
"fmt"
"os"
"runtime"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/cpuid"
"gvisor.dev/gvisor/pkg/fspath"
"gvisor.dev/gvisor/pkg/memutil"
"gvisor.dev/gvisor/pkg/metric"
"gvisor.dev/gvisor/pkg/sentry/fsbridge"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/kernel/sched"
"gvisor.dev/gvisor/pkg/sentry/limits"
"gvisor.dev/gvisor/pkg/sentry/loader"
"gvisor.dev/gvisor/pkg/sentry/mm"
"gvisor.dev/gvisor/pkg/sentry/pgalloc"
"gvisor.dev/gvisor/pkg/sentry/platform"
"gvisor.dev/gvisor/pkg/sentry/time"
"gvisor.dev/gvisor/pkg/sentry/vfs"
// Platforms are plugable.
_ "gvisor.dev/gvisor/pkg/sentry/platform/kvm"
_ "gvisor.dev/gvisor/pkg/sentry/platform/ptrace"
)
var (
platformFlag = flag.String("platform", "ptrace", "specify which platform to use")
)
// Boot initializes a new bare bones kernel for test.
func Boot() (*kernel.Kernel, error) {
platformCtr, err := platform.Lookup(*platformFlag)
if err != nil {
return nil, fmt.Errorf("platform not found: %v", err)
}
deviceFile, err := platformCtr.OpenDevice()
if err != nil {
return nil, fmt.Errorf("creating platform: %v", err)
}
plat, err := platformCtr.New(deviceFile)
if err != nil {
return nil, fmt.Errorf("creating platform: %v", err)
}
metric.CreateSentryMetrics()
kernel.VFS2Enabled = true
k := &kernel.Kernel{
Platform: plat,
}
mf, err := createMemoryFile()
if err != nil {
return nil, err
}
k.SetMemoryFile(mf)
// Pass k as the platform since it is savable, unlike the actual platform.
vdso, err := loader.PrepareVDSO(k)
if err != nil {
return nil, fmt.Errorf("creating vdso: %v", err)
}
// Create timekeeper.
tk, err := kernel.NewTimekeeper(k, vdso.ParamPage.FileRange())
if err != nil {
return nil, fmt.Errorf("creating timekeeper: %v", err)
}
tk.SetClocks(time.NewCalibratedClocks())
k.SetTimekeeper(tk)
creds := auth.NewRootCredentials(auth.NewRootUserNamespace())
// Initiate the Kernel object, which is required by the Context passed
// to createVFS in order to mount (among other things) procfs.
if err = k.Init(kernel.InitKernelArgs{
ApplicationCores: uint(runtime.GOMAXPROCS(-1)),
FeatureSet: cpuid.HostFeatureSet(),
RootUserNamespace: creds.UserNamespace,
Vdso: vdso,
RootUTSNamespace: kernel.NewUTSNamespace("hostname", "domain", creds.UserNamespace),
RootIPCNamespace: kernel.NewIPCNamespace(creds.UserNamespace),
RootAbstractSocketNamespace: kernel.NewAbstractSocketNamespace(),
PIDNamespace: kernel.NewRootPIDNamespace(creds.UserNamespace),
}); err != nil {
return nil, fmt.Errorf("initializing kernel: %v", err)
}
k.VFS().MustRegisterFilesystemType(tmpfs.Name, &tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
AllowUserMount: true,
AllowUserList: true,
})
ls, err := limits.NewLinuxLimitSet()
if err != nil {
return nil, err
}
tg := k.NewThreadGroup(nil, k.RootPIDNamespace(), kernel.NewSignalHandlers(), linux.SIGCHLD, ls)
k.TestOnlySetGlobalInit(tg)
return k, nil
}
// CreateTask creates a new bare bones task for tests.
func CreateTask(ctx context.Context, name string, tc *kernel.ThreadGroup, mntns *vfs.MountNamespace, root, cwd vfs.VirtualDentry) (*kernel.Task, error) {
k := kernel.KernelFromContext(ctx)
if k == nil {
return nil, fmt.Errorf("cannot find kernel from context")
}
exe, err := newFakeExecutable(ctx, k.VFS(), auth.CredentialsFromContext(ctx), root)
if err != nil {
return nil, err
}
m := mm.NewMemoryManager(k, k, k.SleepForAddressSpaceActivation)
m.SetExecutable(ctx, fsbridge.NewVFSFile(exe))
config := &kernel.TaskConfig{
Kernel: k,
ThreadGroup: tc,
TaskImage: &kernel.TaskImage{Name: name, MemoryManager: m},
Credentials: auth.CredentialsFromContext(ctx),
NetworkNamespace: k.RootNetworkNamespace(),
AllowedCPUMask: sched.NewFullCPUSet(k.ApplicationCores()),
UTSNamespace: kernel.UTSNamespaceFromContext(ctx),
IPCNamespace: kernel.IPCNamespaceFromContext(ctx),
AbstractSocketNamespace: kernel.NewAbstractSocketNamespace(),
MountNamespaceVFS2: mntns,
FSContext: kernel.NewFSContextVFS2(root, cwd, 0022),
FDTable: k.NewFDTable(),
}
t, err := k.TaskSet().NewTask(ctx, config)
if err != nil {
config.ThreadGroup.Release(ctx)
return nil, err
}
return t, nil
}
func newFakeExecutable(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, root vfs.VirtualDentry) (*vfs.FileDescription, error) {
const name = "executable"
pop := &vfs.PathOperation{
Root: root,
Start: root,
Path: fspath.Parse(name),
}
opts := &vfs.OpenOptions{
Flags: linux.O_RDONLY | linux.O_CREAT,
Mode: 0777,
}
return vfsObj.OpenAt(ctx, creds, pop, opts)
}
func createMemoryFile() (*pgalloc.MemoryFile, error) {
const memfileName = "test-memory"
memfd, err := memutil.CreateMemFD(memfileName, 0)
if err != nil {
return nil, fmt.Errorf("error creating memfd: %v", err)
}
memfile := os.NewFile(uintptr(memfd), memfileName)
mf, err := pgalloc.NewMemoryFile(memfile, pgalloc.MemoryFileOpts{})
if err != nil {
_ = memfile.Close()
return nil, fmt.Errorf("error creating pgalloc.MemoryFile: %v", err)
}
return mf, nil
}
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