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// +build linux
package nsinit
import (
"os"
"os/exec"
"syscall"
"github.com/dotcloud/docker/pkg/cgroups"
"github.com/dotcloud/docker/pkg/libcontainer"
"github.com/dotcloud/docker/pkg/libcontainer/network"
"github.com/dotcloud/docker/pkg/system"
)
// Exec performes setup outside of a namespace so that a container can be
// executed. Exec is a high level function for working with container namespaces.
func (ns *linuxNs) Exec(container *libcontainer.Container, term Terminal, args []string) (int, error) {
var (
master *os.File
console string
err error
)
// create a pipe so that we can syncronize with the namespaced process and
// pass the veth name to the child
syncPipe, err := NewSyncPipe()
if err != nil {
return -1, err
}
ns.logger.Printf("created sync pipe parent fd %d child fd %d\n", syncPipe.parent.Fd(), syncPipe.child.Fd())
if container.Tty {
ns.logger.Println("creating master and console")
master, console, err = system.CreateMasterAndConsole()
if err != nil {
return -1, err
}
term.SetMaster(master)
}
command := ns.commandFactory.Create(container, console, syncPipe.child, args)
ns.logger.Println("attach terminal to command")
if err := term.Attach(command); err != nil {
return -1, err
}
defer term.Close()
ns.logger.Println("starting command")
if err := command.Start(); err != nil {
return -1, err
}
started, err := system.GetProcessStartTime(command.Process.Pid)
if err != nil {
return -1, err
}
ns.logger.Printf("writting pid %d to file\n", command.Process.Pid)
if err := ns.stateWriter.WritePid(command.Process.Pid, started); err != nil {
command.Process.Kill()
return -1, err
}
defer func() {
ns.logger.Println("removing pid file")
ns.stateWriter.DeletePid()
}()
// Do this before syncing with child so that no children
// can escape the cgroup
ns.logger.Println("setting cgroups")
activeCgroup, err := ns.SetupCgroups(container, command.Process.Pid)
if err != nil {
command.Process.Kill()
return -1, err
}
if activeCgroup != nil {
defer activeCgroup.Cleanup()
}
ns.logger.Println("setting up network")
if err := ns.InitializeNetworking(container, command.Process.Pid, syncPipe); err != nil {
command.Process.Kill()
return -1, err
}
ns.logger.Println("closing sync pipe with child")
// Sync with child
syncPipe.Close()
if err := command.Wait(); err != nil {
if _, ok := err.(*exec.ExitError); !ok {
return -1, err
}
}
status := command.ProcessState.Sys().(syscall.WaitStatus).ExitStatus()
ns.logger.Printf("process exited with status %d\n", status)
return status, err
}
func (ns *linuxNs) SetupCgroups(container *libcontainer.Container, nspid int) (cgroups.ActiveCgroup, error) {
if container.Cgroups != nil {
return container.Cgroups.Apply(nspid)
}
return nil, nil
}
func (ns *linuxNs) InitializeNetworking(container *libcontainer.Container, nspid int, pipe *SyncPipe) error {
context := libcontainer.Context{}
for _, config := range container.Networks {
strategy, err := network.GetStrategy(config.Type)
if err != nil {
return err
}
if err := strategy.Create(config, nspid, context); err != nil {
return err
}
}
return pipe.SendToChild(context)
}
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