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// +build linux
package main
import (
"encoding/json"
"fmt"
"os"
"os/exec"
"strconv"
"strings"
"github.com/urfave/cli"
)
var psCommand = cli.Command{
Name: "ps",
Usage: "ps displays the processes running inside a container",
ArgsUsage: `<container-id> [ps options]`,
Flags: []cli.Flag{
cli.StringFlag{
Name: "format, f",
Value: "table",
Usage: `select one of: ` + formatOptions,
},
},
Action: func(context *cli.Context) error {
if err := checkArgs(context, 1, minArgs); err != nil {
return err
}
// XXX: Currently not supported with rootless containers.
rootless, err := isRootless(context)
if err != nil {
return err
}
if rootless {
return fmt.Errorf("runc ps requires root")
}
container, err := getContainer(context)
if err != nil {
return err
}
pids, err := container.Processes()
if err != nil {
return err
}
switch context.String("format") {
case "table":
case "json":
return json.NewEncoder(os.Stdout).Encode(pids)
default:
return fmt.Errorf("invalid format option")
}
// [1:] is to remove command name, ex:
// context.Args(): [containet_id ps_arg1 ps_arg2 ...]
// psArgs: [ps_arg1 ps_arg2 ...]
//
psArgs := context.Args()[1:]
if len(psArgs) == 0 {
psArgs = []string{"-ef"}
}
cmd := exec.Command("ps", psArgs...)
output, err := cmd.CombinedOutput()
if err != nil {
return fmt.Errorf("%s: %s", err, output)
}
lines := strings.Split(string(output), "\n")
pidIndex, err := getPidIndex(lines[0])
if err != nil {
return err
}
fmt.Println(lines[0])
for _, line := range lines[1:] {
if len(line) == 0 {
continue
}
fields := strings.Fields(line)
p, err := strconv.Atoi(fields[pidIndex])
if err != nil {
return fmt.Errorf("unexpected pid '%s': %s", fields[pidIndex], err)
}
for _, pid := range pids {
if pid == p {
fmt.Println(line)
break
}
}
}
return nil
},
SkipArgReorder: true,
}
func getPidIndex(title string) (int, error) {
titles := strings.Fields(title)
pidIndex := -1
for i, name := range titles {
if name == "PID" {
return i, nil
}
}
return pidIndex, fmt.Errorf("couldn't find PID field in ps output")
}