runc/nsinit/command.go

48 lines
1.5 KiB
Go

package nsinit
import (
"github.com/dotcloud/docker/pkg/libcontainer"
"github.com/dotcloud/docker/pkg/system"
"os"
"os/exec"
)
// CommandFactory takes the container's configuration and options passed by the
// parent processes and creates an *exec.Cmd that will be used to fork/exec the
// namespaced init process
type CommandFactory interface {
Create(container *libcontainer.Container, console string, syncFd *os.File, args []string) *exec.Cmd
}
type DefaultCommandFactory struct {
Root string
}
// Create will return an exec.Cmd with the Cloneflags set to the proper namespaces
// defined on the container's configuration and use the current binary as the init with the
// args provided
func (c *DefaultCommandFactory) Create(container *libcontainer.Container, console string, pipe *os.File, args []string) *exec.Cmd {
// get our binary name from arg0 so we can always reexec ourself
command := exec.Command(os.Args[0], append([]string{
"-console", console,
"-pipe", "3",
"-root", c.Root,
"init"}, args...)...)
system.SetCloneFlags(command, uintptr(GetNamespaceFlags(container.Namespaces)))
command.Env = container.Env
command.ExtraFiles = []*os.File{pipe}
return command
}
// GetNamespaceFlags parses the container's Namespaces options to set the correct
// flags on clone, unshare, and setns
func GetNamespaceFlags(namespaces libcontainer.Namespaces) (flag int) {
for _, ns := range namespaces {
if ns.Enabled {
flag |= ns.Value
}
}
return flag
}