Added code for a pause command for a container process.

Like runc, the pause command will pause the processes of the given container.
It will set that container's status to "paused."
A resume command will be be added to unpause and continue running the process.

PiperOrigin-RevId: 200789624
Change-Id: I72a5d7813d90ecfc4d01cc252d6018855016b1ea

2 files changed, 68 insertions, 0 deletions

diff --git a/runsc/cmd/BUILD b/runsc/cmd/BUILD
index 63d8036bd..8fbce294f 100644
--- a/runsc/cmd/BUILD
+++ b/runsc/cmd/BUILD
@@ -17,6 +17,7 @@ go_library(
         "kill.go",
         "list.go",
         "path.go",
+        "pause.go",
         "ps.go",
         "restore.go",
         "run.go",
diff --git a/runsc/cmd/pause.go b/runsc/cmd/pause.go
new file mode 100644
index 000000000..ac393b48e
--- /dev/null
+++ b/runsc/cmd/pause.go
@@ -0,0 +1,67 @@
+// 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 cmd
+
+import (
+	"context"
+	"flag"
+	"github.com/google/subcommands"
+	"gvisor.googlesource.com/gvisor/runsc/boot"
+	"gvisor.googlesource.com/gvisor/runsc/container"
+)
+
+// Pause implements subcommands.Command for the "pause" command.
+type Pause struct{}
+
+// Name implements subcommands.Command.Name.
+func (*Pause) Name() string {
+	return "pause"
+}
+
+// Synopsis implements subcommands.Command.Synopsis.
+func (*Pause) Synopsis() string {
+	return "pause suspends all processes in a container"
+}
+
+// Usage implements subcommands.Command.Usage.
+func (*Pause) Usage() string {
+	return `pause <container id> - pause process in instance of container.`
+}
+
+// SetFlags implements subcommands.Command.SetFlags.
+func (*Pause) SetFlags(f *flag.FlagSet) {
+}
+
+// Execute implements subcommands.Command.Execute.
+func (*Pause) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
+	if f.NArg() != 1 {
+		f.Usage()
+		return subcommands.ExitUsageError
+	}
+
+	id := f.Arg(0)
+	conf := args[0].(*boot.Config)
+
+	cont, err := container.Load(conf.RootDir, id)
+	if err != nil {
+		Fatalf("error loading container: %v", err)
+	}
+
+	if err := cont.Pause(); err != nil {
+		Fatalf("pause failed: %v", err)
+	}
+
+	return subcommands.ExitSuccess
+}