1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
|
package utils
import (
"bytes"
"fmt"
"io"
"os/exec"
"strings"
systemdDbus "github.com/coreos/go-systemd/dbus"
"github.com/godbus/dbus"
"github.com/pkg/errors"
)
// 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),
}
}
// ErrDetach is an error indicating that the user manually detached from the
// container.
var ErrDetach = errors.New("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, ErrDetach
}
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
}
|
