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package utils
import (
"bytes"
"fmt"
"io"
"os/exec"
"strings"
systemdDbus "github.com/coreos/go-systemd/dbus"
"github.com/godbus/dbus"
)
// ExecCmd executes a command with args and returns its output as a string along
// with an error, if any
func ExecCmd(name string, args ...string) (string, error) {
cmd := exec.Command(name, args...)
var stdout bytes.Buffer
var stderr bytes.Buffer
cmd.Stdout = &stdout
cmd.Stderr = &stderr
err := cmd.Run()
if err != nil {
return "", fmt.Errorf("`%v %v` failed: %v %v (%v)", name, strings.Join(args, " "), stderr.String(), stdout.String(), err)
}
return stdout.String(), nil
}
// ExecCmdWithStdStreams execute a command with the specified standard streams.
func ExecCmdWithStdStreams(stdin io.Reader, stdout, stderr io.Writer, env []string, name string, args ...string) error {
cmd := exec.Command(name, args...)
cmd.Stdin = stdin
cmd.Stdout = stdout
cmd.Stderr = stderr
if env != nil {
cmd.Env = env
}
err := cmd.Run()
if err != nil {
return fmt.Errorf("`%v %v` failed: %v", name, strings.Join(args, " "), err)
}
return nil
}
// StatusToExitCode converts wait status code to an exit code
func StatusToExitCode(status int) int {
return ((status) & 0xff00) >> 8
}
// RunUnderSystemdScope adds the specified pid to a systemd scope
func RunUnderSystemdScope(pid int, slice string, unitName string) error {
var properties []systemdDbus.Property
conn, err := systemdDbus.New()
if err != nil {
return err
}
properties = append(properties, systemdDbus.PropSlice(slice))
properties = append(properties, newProp("PIDs", []uint32{uint32(pid)}))
properties = append(properties, newProp("Delegate", true))
properties = append(properties, newProp("DefaultDependencies", false))
ch := make(chan string)
_, err = conn.StartTransientUnit(unitName, "replace", properties, ch)
if err != nil {
return err
}
defer conn.Close()
// Block until job is started
<-ch
return nil
}
func newProp(name string, units interface{}) systemdDbus.Property {
return systemdDbus.Property{
Name: name,
Value: dbus.MakeVariant(units),
}
}
// DetachError is special error which returned in case of container detach.
type DetachError struct{}
func (DetachError) Error() string {
return "detached from container"
}
// CopyDetachable is similar to io.Copy but support a detach key sequence to break out.
func CopyDetachable(dst io.Writer, src io.Reader, keys []byte) (written int64, err error) {
if len(keys) == 0 {
// Default keys : ctrl-p ctrl-q
keys = []byte{16, 17}
}
buf := make([]byte, 32*1024)
for {
nr, er := src.Read(buf)
if nr > 0 {
preservBuf := []byte{}
for i, key := range keys {
preservBuf = append(preservBuf, buf[0:nr]...)
if nr != 1 || buf[0] != key {
break
}
if i == len(keys)-1 {
// src.Close()
return 0, DetachError{}
}
nr, er = src.Read(buf)
}
var nw int
var ew error
if len(preservBuf) > 0 {
nw, ew = dst.Write(preservBuf)
nr = len(preservBuf)
} else {
nw, ew = dst.Write(buf[0:nr])
}
if nw > 0 {
written += int64(nw)
}
if ew != nil {
err = ew
break
}
if nr != nw {
err = io.ErrShortWrite
break
}
}
if er != nil {
if er != io.EOF {
err = er
}
break
}
}
return written, err
}
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