// ExecIn uses an existing pid and joins the pid's namespaces with the new command.
func ExecIn(container *libcontainer.Container, nspid int, args []string) error {
// TODO(vmarmol): If this gets too long, send it over a pipe to the child.
// Marshall the container into JSON since it won't be available in the namespace.
containerJson, err := json.Marshal(container)
if err != nil {
return err
}
// TODO(vmarmol): Move this to the container JSON.
processLabel, err := label.GetPidCon(nspid)
if err != nil {
return err
}
// Enter the namespace and then finish setup
finalArgs := []string{os.Args[0], "nsenter", strconv.Itoa(nspid), processLabel, string(containerJson)}
finalArgs = append(finalArgs, args...)
if err := system.Execv(finalArgs[0], finalArgs[0:], os.Environ()); err != nil {
return err
}
panic("unreachable")
}
// ExecIn uses an existing pid and joins the pid's namespaces with the new command.
func ExecIn(container *libcontainer.Container, nspid int, args []string) (int, error) {
// clear the current processes env and replace it with the environment
// defined on the container
if err := LoadContainerEnvironment(container); err != nil {
return -1, err
}
for key, enabled := range container.Namespaces {
// skip the PID namespace on unshare because it it not supported
if enabled && key != "NEWPID" {
if ns := libcontainer.GetNamespace(key); ns != nil {
if err := system.Unshare(ns.Value); err != nil {
return -1, err
}
}
}
}
fds, err := getNsFds(nspid, container)
closeFds := func() {
for _, f := range fds {
system.Closefd(f)
}
}
if err != nil {
closeFds()
return -1, err
}
processLabel, err := label.GetPidCon(nspid)
if err != nil {
closeFds()
return -1, err
}
// foreach namespace fd, use setns to join an existing container's namespaces
for _, fd := range fds {
if fd > 0 {
if err := system.Setns(fd, 0); err != nil {
closeFds()
return -1, fmt.Errorf("setns %s", err)
}
}
system.Closefd(fd)
}
// if the container has a new pid and mount namespace we need to
// remount proc and sys to pick up the changes
if container.Namespaces["NEWNS"] && container.Namespaces["NEWPID"] {
pid, err := system.Fork()
if err != nil {
return -1, err
}
if pid == 0 {
// TODO: make all raw syscalls to be fork safe
if err := system.Unshare(syscall.CLONE_NEWNS); err != nil {
return -1, err
}
if err := mount.RemountProc(); err != nil {
return -1, fmt.Errorf("remount proc %s", err)
}
if err := mount.RemountSys(); err != nil {
return -1, fmt.Errorf("remount sys %s", err)
}
goto dropAndExec
}
proc, err := os.FindProcess(pid)
if err != nil {
return -1, err
}
state, err := proc.Wait()
if err != nil {
return -1, err
}
os.Exit(state.Sys().(syscall.WaitStatus).ExitStatus())
}
dropAndExec:
if err := FinalizeNamespace(container); err != nil {
return -1, err
}
err = label.SetProcessLabel(processLabel)
if err != nil {
return -1, err
}
if err := system.Execv(args[0], args[0:], container.Env); err != nil {
return -1, err
}
panic("unreachable")
}
// ExecIn uses an existing pid and joins the pid's namespaces with the new command.
func (ns *linuxNs) ExecIn(container *libcontainer.Container, nspid int, args []string) (int, error) {
for _, nsv := range container.Namespaces {
// skip the PID namespace on unshare because it it not supported
if nsv.Key != "NEWPID" {
if err := system.Unshare(nsv.Value); err != nil {
return -1, err
}
}
}
fds, err := ns.getNsFds(nspid, container)
closeFds := func() {
for _, f := range fds {
system.Closefd(f)
}
}
if err != nil {
closeFds()
return -1, err
}
processLabel, err := label.GetPidCon(nspid)
if err != nil {
closeFds()
return -1, err
}
// foreach namespace fd, use setns to join an existing container's namespaces
for _, fd := range fds {
if fd > 0 {
ns.logger.Printf("setns on %d\n", fd)
if err := system.Setns(fd, 0); err != nil {
closeFds()
return -1, fmt.Errorf("setns %s", err)
}
}
system.Closefd(fd)
}
// if the container has a new pid and mount namespace we need to
// remount proc and sys to pick up the changes
if container.Namespaces.Contains("NEWNS") && container.Namespaces.Contains("NEWPID") {
ns.logger.Println("forking to remount /proc and /sys")
pid, err := system.Fork()
if err != nil {
return -1, err
}
if pid == 0 {
// TODO: make all raw syscalls to be fork safe
if err := system.Unshare(syscall.CLONE_NEWNS); err != nil {
return -1, err
}
if err := mount.RemountProc(); err != nil {
return -1, fmt.Errorf("remount proc %s", err)
}
if err := mount.RemountSys(); err != nil {
return -1, fmt.Errorf("remount sys %s", err)
}
goto dropAndExec
}
proc, err := os.FindProcess(pid)
if err != nil {
return -1, err
}
state, err := proc.Wait()
if err != nil {
return -1, err
}
os.Exit(state.Sys().(syscall.WaitStatus).ExitStatus())
}
dropAndExec:
if err := finalizeNamespace(container); err != nil {
return -1, err
}
err = label.SetProcessLabel(processLabel)
if err != nil {
return -1, err
}
if err := system.Execv(args[0], args[0:], container.Env); err != nil {
return -1, err
}
panic("unreachable")
}