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// +build linux
package main
import (
"encoding/json"
"fmt"
"os"
"strconv"
"strings"
"github.com/opencontainers/runc/libcontainer"
"github.com/opencontainers/runc/libcontainer/utils"
"github.com/opencontainers/runtime-spec/specs-go"
"github.com/urfave/cli"
)
var execCommand = cli.Command{
Name: "exec",
Usage: "execute new process inside the container",
ArgsUsage: `<container-id> <command> [command options] || -p process.json <container-id>
Where "<container-id>" is the name for the instance of the container and
"<command>" is the command to be executed in the container.
"<command>" can't be empty unless a "-p" flag provided.
EXAMPLE:
For example, if the container is configured to run the linux ps command the
following will output a list of processes running in the container:
# runc exec <container-id> ps`,
Flags: []cli.Flag{
cli.StringFlag{
Name: "console-socket",
Usage: "path to an AF_UNIX socket which will receive a file descriptor referencing the master end of the console's pseudoterminal",
},
cli.StringFlag{
Name: "cwd",
Usage: "current working directory in the container",
},
cli.StringSliceFlag{
Name: "env, e",
Usage: "set environment variables",
},
cli.BoolFlag{
Name: "tty, t",
Usage: "allocate a pseudo-TTY",
},
cli.StringFlag{
Name: "user, u",
Usage: "UID (format: <uid>[:<gid>])",
},
cli.StringFlag{
Name: "process, p",
Usage: "path to the process.json",
},
cli.BoolFlag{
Name: "detach,d",
Usage: "detach from the container's process",
},
cli.StringFlag{
Name: "pid-file",
Value: "",
Usage: "specify the file to write the process id to",
},
cli.StringFlag{
Name: "process-label",
Usage: "set the asm process label for the process commonly used with selinux",
},
cli.StringFlag{
Name: "apparmor",
Usage: "set the apparmor profile for the process",
},
cli.BoolFlag{
Name: "no-new-privs",
Usage: "set the no new privileges value for the process",
},
cli.StringSliceFlag{
Name: "cap, c",
Value: &cli.StringSlice{},
Usage: "add a capability to the bounding set for the process",
},
cli.BoolFlag{
Name: "no-subreaper",
Usage: "disable the use of the subreaper used to reap reparented processes",
Hidden: true,
},
},
Action: func(context *cli.Context) error {
if err := checkArgs(context, 1, minArgs); err != nil {
return err
}
if os.Geteuid() != 0 {
return fmt.Errorf("runc should be run as root")
}
if err := revisePidFile(context); err != nil {
return err
}
status, err := execProcess(context)
if err == nil {
os.Exit(status)
}
return fmt.Errorf("exec failed: %v", err)
},
SkipArgReorder: true,
}
func execProcess(context *cli.Context) (int, error) {
container, err := getContainer(context)
if err != nil {
return -1, err
}
status, err := container.Status()
if err != nil {
return -1, err
}
if status == libcontainer.Stopped {
return -1, fmt.Errorf("cannot exec a container that has run and stopped")
}
path := context.String("process")
if path == "" && len(context.Args()) == 1 {
return -1, fmt.Errorf("process args cannot be empty")
}
detach := context.Bool("detach")
state, err := container.State()
if err != nil {
return -1, err
}
bundle := utils.SearchLabels(state.Config.Labels, "bundle")
p, err := getProcess(context, bundle)
if err != nil {
return -1, err
}
r := &runner{
enableSubreaper: false,
shouldDestroy: false,
container: container,
consoleSocket: context.String("console-socket"),
detach: detach,
pidFile: context.String("pid-file"),
}
return r.run(p)
}
func getProcess(context *cli.Context, bundle string) (*specs.Process, error) {
if path := context.String("process"); path != "" {
f, err := os.Open(path)
if err != nil {
return nil, err
}
defer f.Close()
var p specs.Process
if err := json.NewDecoder(f).Decode(&p); err != nil {
return nil, err
}
return &p, validateProcessSpec(&p)
}
// process via cli flags
if err := os.Chdir(bundle); err != nil {
return nil, err
}
spec, err := loadSpec(specConfig)
if err != nil {
return nil, err
}
p := spec.Process
p.Args = context.Args()[1:]
// override the cwd, if passed
if context.String("cwd") != "" {
p.Cwd = context.String("cwd")
}
if ap := context.String("apparmor"); ap != "" {
p.ApparmorProfile = ap
}
if l := context.String("process-label"); l != "" {
p.SelinuxLabel = l
}
if caps := context.StringSlice("cap"); len(caps) > 0 {
p.Capabilities = caps
}
// append the passed env variables
p.Env = append(p.Env, context.StringSlice("env")...)
// set the tty
if context.IsSet("tty") {
p.Terminal = context.Bool("tty")
}
if context.IsSet("no-new-privs") {
p.NoNewPrivileges = context.Bool("no-new-privs")
}
// override the user, if passed
if context.String("user") != "" {
u := strings.SplitN(context.String("user"), ":", 2)
if len(u) > 1 {
gid, err := strconv.Atoi(u[1])
if err != nil {
return nil, fmt.Errorf("parsing %s as int for gid failed: %v", u[1], err)
}
p.User.GID = uint32(gid)
}
uid, err := strconv.Atoi(u[0])
if err != nil {
return nil, fmt.Errorf("parsing %s as int for uid failed: %v", u[0], err)
}
p.User.UID = uint32(uid)
}
return &p, nil
}