kpod exec

Initial wiring of kpod exec. We wont support the following options
for exec:

* detach -- unsure of use case
* detach-keys -- not supported by runc
* interactive -- all terminals will be interactive

Not adding exec tests as we need to think about how to support a
test that requires console access but our CI tests have no console.

Signed-off-by: baude <bbaude@redhat.com>

10 files changed, 334 insertions, 3 deletions

diff --git a/README.md b/README.md
index 049dbf00a..967682cb3 100644
--- a/README.md
+++ b/README.md
@@ -37,6 +37,7 @@ libpod is currently in active development.
 | [kpod-attach(1)](/docs/kpod-attach.1.md)             | Attach to a running container.
 | [kpod-cp(1)](/docs/kpod-cp.1.md)                     | Instead of providing a `kpod cp` command, the man page `kpod-cp` describes how to use the `kpod mount` command to have even more flexibility and functionality.||
 | [kpod-diff(1)](/docs/kpod-diff.1.md)                 | Inspect changes on a container or image's filesystem                      |[![...](/docs/play.png)](https://asciinema.org/a/FXfWB9CKYFwYM4EfqW3NSZy1G)|
+| [kpod-exec(1)](/docs/kpod-exec.1.md)                 | Execute a command in a running container.
 | [kpod-export(1)](/docs/kpod-export.1.md)             | Export container's filesystem contents as a tar archive                   |[![...](/docs/play.png)](https://asciinema.org/a/913lBIRAg5hK8asyIhhkQVLtV)|
 | [kpod-history(1)](/docs/kpod-history.1.md)           | Shows the history of an image                                             |[![...](/docs/play.png)](https://asciinema.org/a/bCvUQJ6DkxInMELZdc5DinNSx)|
 | [kpod-images(1)](/docs/kpod-images.1.md)             | List images in local storage                                              |[![...](/docs/play.png)](https://asciinema.org/a/133649)|
diff --git a/cmd/kpod/exec.go b/cmd/kpod/exec.go
new file mode 100644
index 000000000..f76983810
--- /dev/null
+++ b/cmd/kpod/exec.go
@@ -0,0 +1,86 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/pkg/errors"
+	"github.com/projectatomic/libpod/libpod"
+	"github.com/urfave/cli"
+)
+
+var (
+	execFlags = []cli.Flag{
+		cli.StringSliceFlag{
+			Name:  "env, e",
+			Usage: "Set environment variables",
+		},
+		cli.BoolFlag{
+			Name:  "privileged",
+			Usage: "Give the process extended Linux capabilities inside the container.  The default is false",
+		},
+		cli.BoolFlag{
+			Name:  "tty, t",
+			Usage: "Allocate a pseudo-TTY. The default is false",
+		},
+		cli.StringFlag{
+			Name:  "user, u",
+			Usage: "Sets the username or UID used and optionally the groupname or GID for the specified command",
+		},
+	}
+	execDescription = `
+	kpod exec
+
+	Run a command in a running container
+`
+
+	execCommand = cli.Command{
+		Name:        "exec",
+		Usage:       "Run a process in a running container",
+		Description: execDescription,
+		Flags:       execFlags,
+		Action:      execCmd,
+		ArgsUsage:   "CONTAINER-NAME",
+	}
+)
+
+func execCmd(c *cli.Context) error {
+	var envs []string
+	args := c.Args()
+	if len(args) < 1 {
+		return errors.Errorf("you must provide one container name or id")
+	}
+	if len(args) < 2 {
+		return errors.Errorf("you must provide a command to exec")
+	}
+	cmd := args[1:]
+	runtime, err := getRuntime(c)
+	if err != nil {
+		return errors.Wrapf(err, "error creating libpod runtime")
+	}
+	defer runtime.Shutdown(false)
+
+	ctr, err := runtime.LookupContainer(args[0])
+	if err != nil {
+		return errors.Wrapf(err, "unable to exec into %s", args[0])
+	}
+	// Create a list of keys provided by the user
+	var userEnvKeys []string
+	for _, env := range c.StringSlice("env") {
+		splitEnv := strings.Split(env, "=")
+		userEnvKeys = append(userEnvKeys, splitEnv[0])
+	}
+
+	envs = append(envs, c.StringSlice("env")...)
+
+	// if the default key isnt in the user-provided list, add the default
+	// key and value to the environment variables.  this is needed to set
+	// PATH for example.
+	for k, v := range defaultEnvVariables {
+		if !libpod.StringInSlice(k, userEnvKeys) {
+			envs = append(envs, fmt.Sprintf("%s=%s", k, v))
+		}
+	}
+
+	return ctr.Exec(c.Bool("tty"), c.Bool("privileged"), envs, cmd, c.String("user"))
+}
diff --git a/cmd/kpod/main.go b/cmd/kpod/main.go
index 7382644b9..708031dc9 100644
--- a/cmd/kpod/main.go
+++ b/cmd/kpod/main.go
@@ -37,6 +37,7 @@ func main() {
 		attachCommand,
 		createCommand,
 		diffCommand,
+		execCommand,
 		exportCommand,
 		historyCommand,
 		imagesCommand,
diff --git a/completions/bash/kpod b/completions/bash/kpod
index a5da95a3e..6c66c63c0 100644
--- a/completions/bash/kpod
+++ b/completions/bash/kpod
@@ -682,6 +682,21 @@ _kpod_diff() {
     esac
 }
 
+_kpod_exec() {
+    local options_with_args="
+    -e
+    --env
+    --user
+    -u
+     "
+    local boolean_options="
+    --privileged
+    --tty
+    -t
+     "
+    _complete_ "$options_with_args" "$boolean_options"
+
+}
 _kpod_export() {
     local options_with_args="
      --output
@@ -1437,6 +1452,7 @@ _kpod_kpod() {
     attach
     create
     diff
+    exec
     export
     history
     images
diff --git a/docs/kpod-exec.1.md b/docs/kpod-exec.1.md
new file mode 100644
index 000000000..1de5da39b
--- /dev/null
+++ b/docs/kpod-exec.1.md
@@ -0,0 +1,43 @@
+% kpod(1) kpod-exec - Execute a command in a running container
+% Brent Baude
+# kpod-exec "1" "December 2017" "kpod"
+
+## NAME
+kpod-exec - Execute a command in a running container
+
+## SYNOPSIS
+**kpod exec**
+**CONTAINER**
+[COMMAND] [ARG...]
+[**--help**|**-h**]
+
+## DESCRIPTION
+**kpod exec** executes a command in a running container.
+
+## OPTIONS
+**--env, e**
+You may specify arbitrary environment variables that are available for the
+command to be executed.
+
+**--interactive, -i**
+Not supported.  All exec commands are interactive by default.
+
+**--privileged**
+Give the process extended Linux capabilities when running the command in container.
+
+**--tty, -t**
+Allocate a pseudo-TTY.
+
+**--user, -u**
+Sets the username or UID used and optionally the groupname or GID for the specified command.
+The following examples are all valid:
+--user [user | user:group | uid | uid:gid | user:gid | uid:group ]
+
+## EXAMPLES
+
+
+## SEE ALSO
+kpod(1), kpod-run(1)
+
+## HISTORY
+December 2017, Originally compiled by Brent Baude<bbaude@redhat.com>
diff --git a/docs/kpod.1.md b/docs/kpod.1.md
index 7009289c7..dec29e395 100644
--- a/docs/kpod.1.md
+++ b/docs/kpod.1.md
@@ -61,6 +61,9 @@ create a new container
 ### diff
 Inspect changes on a container or image's filesystem
 
+## exec
+Execute a command in a running container.
+
 ### export
 Export container's filesystem contents as a tar archive
 
diff --git a/libpod/container.go b/libpod/container.go
index 40aa689ff..474d4be95 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -14,6 +14,7 @@ import (
 
 	"github.com/containers/storage"
 	"github.com/containers/storage/pkg/archive"
+	"github.com/docker/docker/daemon/caps"
 	"github.com/docker/docker/pkg/mount"
 	"github.com/docker/docker/pkg/namesgenerator"
 	"github.com/docker/docker/pkg/stringid"
@@ -552,9 +553,36 @@ func (c *Container) Kill(signal uint) error {
 }
 
 // Exec starts a new process inside the container
-// Returns fully qualified URL of streaming server for executed process
-func (c *Container) Exec(cmd []string, tty bool, stdin bool) (string, error) {
-	return "", ErrNotImplemented
+func (c *Container) Exec(tty, privileged bool, env, cmd []string, user string) error {
+	var capList []string
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	if err := c.syncContainer(); err != nil {
+		return err
+	}
+
+	conState := c.state.State
+
+	if conState != ContainerStateRunning {
+		return errors.Errorf("cannot attach to container that is not running")
+	}
+	if privileged {
+		capList = caps.GetAllCapabilities()
+	}
+	globalOpts := runcGlobalOptions{
+		log: c.LogPath(),
+	}
+	execOpts := runcExecOptions{
+		capAdd:  capList,
+		pidFile: filepath.Join(c.state.RunDir, fmt.Sprintf("%s-execpid", stringid.GenerateNonCryptoID()[:12])),
+		env:     env,
+		user:    user,
+		cwd:     c.config.Spec.Process.Cwd,
+		tty:     tty,
+	}
+
+	return c.runtime.ociRuntime.execContainer(c, cmd, globalOpts, execOpts)
 }
 
 // Attach attaches to a container
diff --git a/libpod/oci.go b/libpod/oci.go
index 6ea6bb64f..323e97273 100644
--- a/libpod/oci.go
+++ b/libpod/oci.go
@@ -454,3 +454,9 @@ func (r *OCIRuntime) pauseContainer(ctr *Container) error {
 func (r *OCIRuntime) unpauseContainer(ctr *Container) error {
 	return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "resume", ctr.ID())
 }
+
+//execContiner executes a command in a running container
+func (r *OCIRuntime) execContainer(c *Container, cmd []string, globalOpts runcGlobalOptions, commandOpts runcExecOptions) error {
+	r.RuncExec(c, cmd, globalOpts, commandOpts)
+	return nil
+}
diff --git a/libpod/runc.go b/libpod/runc.go
new file mode 100644
index 000000000..efbb51b24
--- /dev/null
+++ b/libpod/runc.go
@@ -0,0 +1,117 @@
+package libpod
+
+import (
+	"os"
+	"os/exec"
+	"strings"
+
+	"github.com/sirupsen/logrus"
+)
+
+type runcGlobalOptions struct {
+	log           string
+	logFormat     string
+	root          string
+	criu          string
+	systemdCgroup bool
+}
+type runcExecOptions struct {
+	consoleSocket string
+	cwd           string
+	env           []string
+	tty           bool
+	user          string
+	processPath   string
+	detach        bool
+	pidFile       string
+	processLabel  string
+	apparmor      string
+	noNewPrivs    bool
+	capAdd        []string
+}
+
+func parseGlobalOptionsToArgs(opts runcGlobalOptions) []string {
+	args := []string{}
+	if opts.log != "" {
+		args = append(args, "--log", opts.log)
+	}
+	if opts.logFormat != "" {
+		args = append(args, "--log-format", opts.logFormat)
+	}
+	if opts.root != "" {
+		args = append(args, "--root", opts.root)
+	}
+	if opts.criu != "" {
+		args = append(args, "--criu", opts.criu)
+	}
+	if opts.systemdCgroup {
+		args = append(args, "--systemd-cgroup")
+	}
+	return args
+}
+
+// RuncExec executes 'runc --options exec --options cmd'
+func (r *OCIRuntime) RuncExec(container *Container, command []string, globalOpts runcGlobalOptions, execOpts runcExecOptions) error {
+	args := []string{}
+	args = append(args, parseGlobalOptionsToArgs(globalOpts)...)
+	// Add subcommand
+	args = append(args, "exec")
+	// Now add subcommand args
+
+	if execOpts.consoleSocket != "" {
+		args = append(args, "--console-socket", execOpts.consoleSocket)
+	}
+	if execOpts.cwd != "" {
+		args = append(args, "--cwd", execOpts.cwd)
+	}
+
+	if len(execOpts.env) > 0 {
+		for _, envInput := range execOpts.env {
+			args = append(args, "--env", envInput)
+		}
+	}
+	if execOpts.tty {
+		args = append(args, "--tty")
+	}
+	if execOpts.user != "" {
+		args = append(args, "--user", execOpts.user)
+
+	}
+	if execOpts.processPath != "" {
+		args = append(args, "--process", execOpts.processPath)
+	}
+	if execOpts.detach {
+		args = append(args, "--detach")
+	}
+	if execOpts.pidFile != "" {
+		args = append(args, "--pid-file", execOpts.pidFile)
+	}
+	if execOpts.processLabel != "" {
+		args = append(args, "--process-label", execOpts.processLabel)
+	}
+	if execOpts.apparmor != "" {
+		args = append(args, "--apparmor", execOpts.apparmor)
+	}
+	if execOpts.noNewPrivs {
+		args = append(args, "--no-new-privs")
+	}
+	if len(execOpts.capAdd) > 0 {
+		for _, capAddValue := range execOpts.capAdd {
+			args = append(args, "--cap", capAddValue)
+		}
+	}
+
+	// Append Cid
+	args = append(args, container.ID())
+	// Append Cmd
+	args = append(args, command...)
+
+	logrus.Debug("Executing runc command: %s %s", r.path, strings.Join(args, " "))
+	cmd := exec.Command(r.path, args...)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	cmd.Stdin = os.Stdin
+	cmd.Start()
+	err := cmd.Wait()
+	return err
+}
diff --git a/test/kpod_exec.bats b/test/kpod_exec.bats
new file mode 100644
index 000000000..d495b1687
--- /dev/null
+++ b/test/kpod_exec.bats
@@ -0,0 +1,30 @@
+#!/usr/bin/env bats
+
+load helpers
+
+function teardown() {
+    cleanup_test
+}
+
+function setup() {
+    copy_images
+}
+
+@test "exec into a bogus container" {
+    run ${KPOD_BINARY} ${KPOD_OPTIONS} exec foobar ls
+    echo "$output"
+    [ "$status" -eq 1 ]
+}
+
+@test "exec without command should fail" {
+    run ${KPOD_BINARY} ${KPOD_OPTIONS} exec foobar
+    echo "$output"
+    [ "$status" -eq 1 ]
+}
+
+@test "exec simple command" {
+    ${KPOD_BINARY} ${KPOD_OPTIONS} run -d -t --name foobar1 ${ALPINE} sleep 60
+    run ${KPOD_BINARY} ${KPOD_OPTIONS} exec foobar1 ls
+    echo "$output"
+    [ "$status" -eq 0 ]
+}