pkg/libcontainer/namespaces/utils.go
Michael Crosby 81d2c67492 Initial commit of libcontainer
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
2014-02-21 14:56:15 -08:00

108 lines
2.5 KiB
Go

package namespaces
import (
"fmt"
"github.com/dotcloud/docker/pkg/libcontainer"
"os"
"path/filepath"
"strconv"
"strings"
"syscall"
)
func addEnvIfNotSet(container *libcontainer.Container, key, value string) {
jv := fmt.Sprintf("%s=%s", key, value)
if len(container.Command.Env) == 0 {
container.Command.Env = []string{jv}
return
}
for _, v := range container.Command.Env {
parts := strings.Split(v, "=")
if parts[0] == key {
return
}
}
container.Command.Env = append(container.Command.Env, jv)
}
// print and error to stderr and exit(1)
func writeError(format string, v ...interface{}) {
fmt.Fprintf(os.Stderr, format, v...)
os.Exit(1)
}
// getNsFds inspects the container's namespace configuration and opens the fds to
// each of the namespaces.
func getNsFds(container *libcontainer.Container) ([]uintptr, error) {
var (
namespaces = []string{}
fds = []uintptr{}
)
for _, ns := range container.Namespaces {
namespaces = append(namespaces, namespaceFileMap[ns])
}
for _, ns := range namespaces {
fd, err := getNsFd(container.NsPid, ns)
if err != nil {
for _, fd = range fds {
syscall.Close(int(fd))
}
return nil, err
}
fds = append(fds, fd)
}
return fds, nil
}
// getNsFd returns the fd for a specific pid and namespace option
func getNsFd(pid int, ns string) (uintptr, error) {
nspath := filepath.Join("/proc", strconv.Itoa(pid), "ns", ns)
// OpenFile adds closOnExec
f, err := os.OpenFile(nspath, os.O_RDONLY, 0666)
if err != nil {
return 0, err
}
return f.Fd(), nil
}
// setupEnvironment adds additional environment variables to the container's
// Command such as USER, LOGNAME, container, and TERM
func setupEnvironment(container *libcontainer.Container) {
addEnvIfNotSet(container, "container", "docker")
// TODO: check if pty
addEnvIfNotSet(container, "TERM", "xterm")
// TODO: get username from container
addEnvIfNotSet(container, "USER", "root")
addEnvIfNotSet(container, "LOGNAME", "root")
}
func setupUser(container *libcontainer.Container) error {
// TODO: honor user passed on container
if err := setgroups(nil); err != nil {
return err
}
if err := setresgid(0, 0, 0); err != nil {
return err
}
if err := setresuid(0, 0, 0); err != nil {
return err
}
return nil
}
func getMasterAndConsole(container *libcontainer.Container) (string, *os.File, error) {
master, err := openpmtx()
if err != nil {
return "", nil, err
}
console, err := ptsname(master)
if err != nil {
master.Close()
return "", nil, err
}
return console, master, nil
}