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Add syncpipe for passing context

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Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
This commit is contained in:
Michael Crosby 2014-02-21 22:58:30 -08:00
parent c71bc03279
commit 118ca3ae64
4 changed files with 102 additions and 48 deletions
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44
libcontainer/nsinit/init.go
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@ -3,14 +3,11 @@
package nsinit
import (
"encoding/json"
"fmt"
"github.com/dotcloud/docker/pkg/libcontainer"
"github.com/dotcloud/docker/pkg/libcontainer/capabilities"
"github.com/dotcloud/docker/pkg/libcontainer/network"
"github.com/dotcloud/docker/pkg/system"
"io"
"io/ioutil"
"log"
"os"
"os/exec"
@ -20,7 +17,7 @@ import (
// Init is the init process that first runs inside a new namespace to setup mounts, users, networking,
// and other options required for the new container.
func Init(container *libcontainer.Container, uncleanRootfs, console string, pipe io.ReadCloser, args []string) error {
func Init(container *libcontainer.Container, uncleanRootfs, console string, syncPipe *SyncPipe, args []string) error {
rootfs, err := resolveRootfs(uncleanRootfs)
if err != nil {
return err
@ -28,16 +25,18 @@ func Init(container *libcontainer.Container, uncleanRootfs, console string, pipe
log.Printf("initializing namespace at %s", rootfs)
// We always read this as it is a way to sync with the parent as well
context, err := GetContextFromParent(pipe)
context, err := syncPipe.ReadFromParent()
if err != nil {
syncPipe.Close()
return err
}
syncPipe.Close()
log.Printf("received context from parent %v", context)
if console != "" {
log.Printf("setting up console for %s", console)
// close pipes so that we can replace it with the pty
os.Stdin.Close()
os.Stdout.Close()
os.Stderr.Close()
closeStdPipes()
slave, err := openTerminal(console, syscall.O_RDWR)
if err != nil {
return fmt.Errorf("open terminal %s", err)
@ -79,18 +78,27 @@ func Init(container *libcontainer.Container, uncleanRootfs, console string, pipe
return fmt.Errorf("chdir to %s %s", container.WorkingDir, err)
}
}
return execArgs(args, container.Env)
}
func execArgs(args []string, env []string) error {
name, err := exec.LookPath(args[0])
if err != nil {
return err
}
log.Printf("execing %s goodbye", name)
if err := system.Exec(name, args[0:], container.Env); err != nil {
if err := system.Exec(name, args[0:], env); err != nil {
return fmt.Errorf("exec %s", err)
}
panic("unreachable")
}
func closeStdPipes() {
os.Stdin.Close()
os.Stdout.Close()
os.Stderr.Close()
}
// resolveRootfs ensures that the current working directory is
// not a symlink and returns the absolute path to the rootfs
func resolveRootfs(uncleanRootfs string) (string, error) {
@ -153,19 +161,3 @@ func setupNetwork(config *libcontainer.Network, context libcontainer.Context) er
}
return nil
}
func GetContextFromParent(pipe io.ReadCloser) (libcontainer.Context, error) {
defer pipe.Close()
data, err := ioutil.ReadAll(pipe)
if err != nil {
return nil, fmt.Errorf("error reading from stdin %s", err)
}
var context libcontainer.Context
if len(data) > 0 {
if err := json.Unmarshal(data, &context); err != nil {
return nil, err
}
log.Printf("received context %v", context)
}
return context, nil
}