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runsc: Add exec flag that specifies where to save the sandbox-internal pid. 

This is different from the existing -pid-file flag, which saves a host pid.

PiperOrigin-RevId: 212713968
Change-Id: I2c486de8dd5cfd9b923fb0970165ef7c5fc597f0
This commit is contained in:
Kevin Krakauer 2018-09-12 15:22:24 -07:00 committed by Shentubot
parent 0efde2bfbd
commit 2eff1fdd06
6 changed files with 129 additions and 82 deletions
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35
pkg/sentry/control/proc.go
View File

@ -87,6 +87,24 @@ type ExecArgs struct {
// Exec runs a new task.
func (proc *Proc) Exec(args *ExecArgs, waitStatus *uint32) error {
newTG, err := proc.execAsync(args)
if err != nil {
return err
}
// Wait for completion.
newTG.WaitExited()
*waitStatus = newTG.ExitStatus().Status()
return nil
}
// ExecAsync runs a new task, but doesn't wait for it to finish. It is defined
// as a function rather than a method to avoid exposing execAsync as an RPC.
func ExecAsync(proc *Proc, args *ExecArgs) (*kernel.ThreadGroup, error) {
return proc.execAsync(args)
}
func (proc *Proc) execAsync(args *ExecArgs) (*kernel.ThreadGroup, error) {
// Import file descriptors.
l := limits.NewLimitSet()
fdm := proc.Kernel.NewFDMap()
@ -121,7 +139,7 @@ func (proc *Proc) Exec(args *ExecArgs, waitStatus *uint32) error {
paths := fs.GetPath(initArgs.Envv)
f, err := proc.Kernel.RootMountNamespace().ResolveExecutablePath(ctx, initArgs.WorkingDirectory, initArgs.Argv[0], paths)
if err != nil {
return fmt.Errorf("error finding executable %q in PATH %v: %v", initArgs.Argv[0], paths, err)
return nil, fmt.Errorf("error finding executable %q in PATH %v: %v", initArgs.Argv[0], paths, err)
}
initArgs.Filename = f
}
@ -133,7 +151,7 @@ func (proc *Proc) Exec(args *ExecArgs, waitStatus *uint32) error {
// Import the given file FD. This dups the FD as well.
file, err := host.ImportFile(ctx, int(f.Fd()), mounter, enableIoctl)
if err != nil {
return err
return nil, err
}
defer file.DecRef()
@ -141,20 +159,11 @@ func (proc *Proc) Exec(args *ExecArgs, waitStatus *uint32) error {
f.Close()
if err := fdm.NewFDAt(kdefs.FD(appFD), file, kernel.FDFlags{}, l); err != nil {
return err
return nil, err
}
}
// Start the new task.
newTG, err := proc.Kernel.CreateProcess(initArgs)
if err != nil {
return err
}
// Wait for completion.
newTG.WaitExited()
*waitStatus = newTG.ExitStatus().Status()
return nil
return proc.Kernel.CreateProcess(initArgs)
}
// PsArgs is the set of arguments to ps.

33
runsc/boot/controller.go
View File

@ -41,9 +41,9 @@ const (
// container used by "runsc events".
ContainerEvent = "containerManager.Event"
// ContainerExecute is the URPC endpoint for executing a command in a
// ContainerExecuteAsync is the URPC endpoint for executing a command in a
// container..
ContainerExecute = "containerManager.Execute"
ContainerExecuteAsync = "containerManager.ExecuteAsync"
// ContainerPause pauses the container.
ContainerPause = "containerManager.Pause"
@ -233,33 +233,40 @@ type ExecArgs struct {
CID string
}
// Execute runs a command on a created or running sandbox.
func (cm *containerManager) Execute(e *ExecArgs, waitStatus *uint32) error {
log.Debugf("containerManager.Execute: %+v", *e)
// ExecuteAsync starts running a command on a created or running sandbox. It
// returns the pid of the new process.
func (cm *containerManager) ExecuteAsync(args *ExecArgs, pid *int32) error {
log.Debugf("containerManager.ExecuteAsync: %+v", args)
// Get the container Root Dirent from the Task, since we must run this
// process with the same Root.
cm.l.mu.Lock()
tgid, ok := cm.l.containerRootTGIDs[e.CID]
tgid, ok := cm.l.containerRootTGIDs[args.CID]
cm.l.mu.Unlock()
if !ok {
return fmt.Errorf("cannot exec in container %q: no such container", e.CID)
return fmt.Errorf("cannot exec in container %q: no such container", args.CID)
}
t := cm.l.k.TaskSet().Root.TaskWithID(kernel.ThreadID(tgid))
if t == nil {
return fmt.Errorf("cannot exec in container %q: no thread group with ID %d", e.CID, tgid)
return fmt.Errorf("cannot exec in container %q: no thread group with ID %d", args.CID, tgid)
}
t.WithMuLocked(func(t *kernel.Task) {
e.Root = t.FSContext().RootDirectory()
args.Root = t.FSContext().RootDirectory()
})
if e.Root != nil {
defer e.Root.DecRef()
if args.Root != nil {
defer args.Root.DecRef()
}
// Start the process.
proc := control.Proc{Kernel: cm.l.k}
if err := proc.Exec(&e.ExecArgs, waitStatus); err != nil {
return fmt.Errorf("error executing: %+v: %v", e, err)
newTG, err := control.ExecAsync(&proc, &args.ExecArgs)
if err != nil {
return fmt.Errorf("error executing: %+v: %v", args, err)
}
// Return the pid of the newly-created process.
ts := cm.l.k.TaskSet()
*pid = int32(ts.Root.IDOfThreadGroup(newTG))
return nil
}

19
runsc/cmd/exec.go
View File

@ -51,6 +51,7 @@ type Exec struct {
detach bool
processPath string
pidFile string
internalPidFile string
// consoleSocket is the path to an AF_UNIX socket which will receive a
// file descriptor referencing the master end of the console's
@ -97,6 +98,7 @@ func (ex *Exec) SetFlags(f *flag.FlagSet) {
f.BoolVar(&ex.detach, "detach", false, "detach from the container's process")
f.StringVar(&ex.processPath, "process", "", "path to the process.json")
f.StringVar(&ex.pidFile, "pid-file", "", "filename that the container pid will be written to")
f.StringVar(&ex.internalPidFile, "internal-pid-file", "", "filename that the container-internal pid will be written to")
f.StringVar(&ex.consoleSocket, "console-socket", "", "path to an AF_UNIX socket which will receive a file descriptor referencing the master end of the console's pseudoterminal")
}
@ -146,10 +148,25 @@ func (ex *Exec) Execute(_ context.Context, f *flag.FlagSet, args ...interface{})
}
}
ws, err := c.Execute(e)
// Start the new process and get it pid.
pid, err := c.Execute(e)
if err != nil {
Fatalf("error getting processes for container: %v", err)
}
// Write the sandbox-internal pid if required.
if ex.internalPidFile != "" {
pidStr := []byte(strconv.Itoa(int(pid)))
if err := ioutil.WriteFile(ex.internalPidFile, pidStr, 0644); err != nil {
Fatalf("error writing internal pid file %q: %v", ex.internalPidFile, err)
}
}
// Wait for the process to exit.
ws, err := c.WaitPID(pid)
if err != nil {
Fatalf("error waiting on pid %d: %v", pid, err)
}
*waitStatus = ws
return subcommands.ExitSuccess
}

9
runsc/container/container.go
View File

@ -353,13 +353,14 @@ func Run(id string, spec *specs.Spec, conf *boot.Config, bundleDir, consoleSocke
return c.Wait()
}
// Execute runs the specified command in the container.
func (c *Container) Execute(e *control.ExecArgs) (syscall.WaitStatus, error) {
log.Debugf("Execute in container %q, args: %+v", c.ID, e)
// Execute runs the specified command in the container. It returns the pid of
// the newly created process.
func (c *Container) Execute(args *control.ExecArgs) (int32, error) {
log.Debugf("Execute in container %q, args: %+v", c.ID, args)
if c.Status != Created && c.Status != Running {
return 0, fmt.Errorf("cannot exec in container in state %s", c.Status)
}
return c.Sandbox.Execute(c.ID, e)
return c.Sandbox.Execute(c.ID, args)
}
// Event returns events for the container.

84
runsc/container/container_test.go
View File

@ -49,11 +49,11 @@ func init() {
}
// waitForProcessList waits for the given process list to show up in the container.
func waitForProcessList(s *Container, expected []*control.Process) error {
func waitForProcessList(cont *Container, expected []*control.Process) error {
var got []*control.Process
for start := time.Now(); time.Now().Sub(start) < 10*time.Second; {
var err error
got, err = s.Processes()
got, err = cont.Processes()
if err != nil {
return fmt.Errorf("error getting process data from container: %v", err)
}
@ -485,12 +485,12 @@ func TestExec(t *testing.T) {
defer os.RemoveAll(bundleDir)
// Create and start the container.
s, err := Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "")
cont, err := Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "")
if err != nil {
t.Fatalf("error creating container: %v", err)
}
defer s.Destroy()
if err := s.Start(conf); err != nil {
defer cont.Destroy()
if err := cont.Start(conf); err != nil {
t.Fatalf("error starting container: %v", err)
}
@ -513,11 +513,11 @@ func TestExec(t *testing.T) {
}
// Verify that "sleep 100" is running.
if err := waitForProcessList(s, expectedPL[:1]); err != nil {
if err := waitForProcessList(cont, expectedPL[:1]); err != nil {
t.Error(err)
}
execArgs := control.ExecArgs{
args := &control.ExecArgs{
Filename: "/bin/sleep",
Argv: []string{"sleep", "5"},
WorkingDirectory: "/",
@ -528,17 +528,19 @@ func TestExec(t *testing.T) {
// First, start running exec (whick blocks).
status := make(chan error, 1)
go func() {
exitStatus, err := s.Execute(&execArgs)
exitStatus, err := cont.executeSync(args)
if err != nil {
log.Debugf("error executing: %v", err)
status <- err
} else if exitStatus != 0 {
log.Debugf("bad status: %d", exitStatus)
status <- fmt.Errorf("failed with exit status: %v", exitStatus)
} else {
status <- nil
}
}()
if err := waitForProcessList(s, expectedPL); err != nil {
if err := waitForProcessList(cont, expectedPL); err != nil {
t.Fatal(err)
}
@ -548,7 +550,7 @@ func TestExec(t *testing.T) {
t.Fatalf("container timed out waiting for exec to finish.")
case st := <-status:
if st != nil {
t.Errorf("container failed to exec %v: %v", execArgs, err)
t.Errorf("container failed to exec %v: %v", args, err)
}
}
}
@ -884,15 +886,18 @@ func TestPauseResume(t *testing.T) {
}
script := fmt.Sprintf("while [[ -f %q ]]; do sleep 0.1; done", lock.Name())
execArgs := control.ExecArgs{
args := &control.ExecArgs{
Filename: "/bin/bash",
Argv: []string{"bash", "-c", script},
WorkingDirectory: "/",
KUID: uid,
}
// First, start running exec (which blocks).
go cont.Execute(&execArgs)
// First, start running exec.
_, err = cont.Execute(args)
if err != nil {
t.Fatalf("error executing: %v", err)
}
// Verify that "sleep 5" is running.
if err := waitForProcessList(cont, expectedPL); err != nil {
@ -1022,12 +1027,12 @@ func TestCapabilities(t *testing.T) {
defer os.RemoveAll(bundleDir)
// Create and start the container.
s, err := Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "")
cont, err := Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "")
if err != nil {
t.Fatalf("error creating container: %v", err)
}
defer s.Destroy()
if err := s.Start(conf); err != nil {
defer cont.Destroy()
if err := cont.Start(conf); err != nil {
t.Fatalf("error starting container: %v", err)
}
@ -1048,7 +1053,7 @@ func TestCapabilities(t *testing.T) {
Cmd: "exe",
},
}
if err := waitForProcessList(s, expectedPL[:1]); err != nil {
if err := waitForProcessList(cont, expectedPL[:1]); err != nil {
t.Fatalf("Failed to wait for sleep to start, err: %v", err)
}
@ -1064,7 +1069,7 @@ func TestCapabilities(t *testing.T) {
// Need to traverse the intermediate directory.
os.Chmod(rootDir, 0755)
execArgs := control.ExecArgs{
args := &control.ExecArgs{
Filename: exePath,
Argv: []string{exePath},
WorkingDirectory: "/",
@ -1074,17 +1079,17 @@ func TestCapabilities(t *testing.T) {
}
// "exe" should fail because we don't have the necessary permissions.
if _, err := s.Execute(&execArgs); err == nil {
if _, err := cont.executeSync(args); err == nil {
t.Fatalf("container executed without error, but an error was expected")
}
// Now we run with the capability enabled and should succeed.
execArgs.Capabilities = &auth.TaskCapabilities{
args.Capabilities = &auth.TaskCapabilities{
EffectiveCaps: auth.CapabilitySetOf(linux.CAP_DAC_OVERRIDE),
}
// "exe" should not fail this time.
if _, err := s.Execute(&execArgs); err != nil {
t.Fatalf("container failed to exec %v: %v", execArgs, err)
if _, err := cont.executeSync(args); err != nil {
t.Fatalf("container failed to exec %v: %v", args, err)
}
}
}
@ -1404,11 +1409,11 @@ func TestContainerVolumeContentsShared(t *testing.T) {
filename := filepath.Join(dir, "file")
// File does not exist yet. Reading from the sandbox should fail.
execArgsTestFile := control.ExecArgs{
argsTestFile := &control.ExecArgs{
Filename: "/usr/bin/test",
Argv: []string{"test", "-f", filename},
}
if ws, err := c.Execute(&execArgsTestFile); err != nil {
if ws, err := c.executeSync(argsTestFile); err != nil {
t.Fatalf("unexpected error testing file %q: %v", filename, err)
} else if ws.ExitStatus() == 0 {
t.Errorf("test %q exited with code %v, wanted not zero", ws.ExitStatus(), err)
@ -1420,7 +1425,7 @@ func TestContainerVolumeContentsShared(t *testing.T) {
}
// Now we should be able to test the file from within the sandbox.
if ws, err := c.Execute(&execArgsTestFile); err != nil {
if ws, err := c.executeSync(argsTestFile); err != nil {
t.Fatalf("unexpected error testing file %q: %v", filename, err)
} else if ws.ExitStatus() != 0 {
t.Errorf("test %q exited with code %v, wanted zero", filename, ws.ExitStatus())
@ -1433,18 +1438,18 @@ func TestContainerVolumeContentsShared(t *testing.T) {
}
// File should no longer exist at the old path within the sandbox.
if ws, err := c.Execute(&execArgsTestFile); err != nil {
if ws, err := c.executeSync(argsTestFile); err != nil {
t.Fatalf("unexpected error testing file %q: %v", filename, err)
} else if ws.ExitStatus() == 0 {
t.Errorf("test %q exited with code %v, wanted not zero", filename, ws.ExitStatus())
}
// We should be able to test the new filename from within the sandbox.
execArgsTestNewFile := control.ExecArgs{
argsTestNewFile := &control.ExecArgs{
Filename: "/usr/bin/test",
Argv: []string{"test", "-f", newFilename},
}
if ws, err := c.Execute(&execArgsTestNewFile); err != nil {
if ws, err := c.executeSync(argsTestNewFile); err != nil {
t.Fatalf("unexpected error testing file %q: %v", newFilename, err)
} else if ws.ExitStatus() != 0 {
t.Errorf("test %q exited with code %v, wanted zero", newFilename, ws.ExitStatus())
@ -1456,20 +1461,20 @@ func TestContainerVolumeContentsShared(t *testing.T) {
}
// Renamed file should no longer exist at the old path within the sandbox.
if ws, err := c.Execute(&execArgsTestNewFile); err != nil {
if ws, err := c.executeSync(argsTestNewFile); err != nil {
t.Fatalf("unexpected error testing file %q: %v", newFilename, err)
} else if ws.ExitStatus() == 0 {
t.Errorf("test %q exited with code %v, wanted not zero", newFilename, ws.ExitStatus())
}
// Now create the file from WITHIN the sandbox.
execArgsTouch := control.ExecArgs{
argsTouch := &control.ExecArgs{
Filename: "/usr/bin/touch",
Argv: []string{"touch", filename},
KUID: auth.KUID(os.Getuid()),
KGID: auth.KGID(os.Getgid()),
}
if ws, err := c.Execute(&execArgsTouch); err != nil {
if ws, err := c.executeSync(argsTouch); err != nil {
t.Fatalf("unexpected error touching file %q: %v", filename, err)
} else if ws.ExitStatus() != 0 {
t.Errorf("touch %q exited with code %v, wanted zero", filename, ws.ExitStatus())
@ -1486,11 +1491,11 @@ func TestContainerVolumeContentsShared(t *testing.T) {
}
// Delete the file from within the sandbox.
execArgsRemove := control.ExecArgs{
argsRemove := &control.ExecArgs{
Filename: "/bin/rm",
Argv: []string{"rm", filename},
}
if ws, err := c.Execute(&execArgsRemove); err != nil {
if ws, err := c.executeSync(argsRemove); err != nil {
t.Fatalf("unexpected error removing file %q: %v", filename, err)
} else if ws.ExitStatus() != 0 {
t.Errorf("remove %q exited with code %v, wanted zero", filename, ws.ExitStatus())
@ -1547,6 +1552,19 @@ func TestGoferExits(t *testing.T) {
}
}
// executeSync synchronously executes a new process.
func (cont *Container) executeSync(args *control.ExecArgs) (syscall.WaitStatus, error) {
pid, err := cont.Execute(args)
if err != nil {
return 0, fmt.Errorf("error executing: %v", err)
}
ws, err := cont.WaitPID(pid)
if err != nil {
return 0, fmt.Errorf("error waiting: %v", err)
}
return ws, nil
}
func TestMain(m *testing.M) {
testutil.RunAsRoot(m)
}

19
runsc/sandbox/sandbox.go
View File

@ -187,8 +187,9 @@ func (s *Sandbox) Processes(cid string) ([]*control.Process, error) {
return pl, nil
}
// Execute runs the specified command in the container.
func (s *Sandbox) Execute(cid string, e *control.ExecArgs) (syscall.WaitStatus, error) {
// Execute runs the specified command in the container. It returns the pid of
// the newly created process.
func (s *Sandbox) Execute(cid string, args *control.ExecArgs) (int32, error) {
log.Debugf("Executing new process in container %q in sandbox %q", cid, s.ID)
conn, err := s.sandboxConnect()
if err != nil {
@ -196,20 +197,14 @@ func (s *Sandbox) Execute(cid string, e *control.ExecArgs) (syscall.WaitStatus,
}
defer conn.Close()
ea := &boot.ExecArgs{
ExecArgs: *e,
CID: cid,
}
rpcArgs := &boot.ExecArgs{ExecArgs: *args, CID: cid}
// Send a message to the sandbox control server to start the container.
var waitStatus uint32
// TODO: Pass in the container id (cid) here. The sandbox
// should execute in the context of that container.
if err := conn.Call(boot.ContainerExecute, ea, &waitStatus); err != nil {
var pid int32
if err := conn.Call(boot.ContainerExecuteAsync, rpcArgs, &pid); err != nil {
return 0, fmt.Errorf("error executing in sandbox: %v", err)
}
return syscall.WaitStatus(waitStatus), nil
return pid, nil
}
// Event retrieves stats about the sandbox such as memory and CPU utilization.