c1f8606d50
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
76 lines
1.9 KiB
Go
76 lines
1.9 KiB
Go
package namespaces
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import (
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"github.com/dotcloud/docker/pkg/libcontainer"
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"github.com/dotcloud/docker/pkg/system"
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"github.com/dotcloud/docker/pkg/term"
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"io"
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"log"
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"os"
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"os/exec"
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"syscall"
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)
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// ExecContainer will spawn new namespaces with the specified Container configuration
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// in the RootFs path and return the pid of the new containerized process.
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//
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// If an existing network namespace is specified the container
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// will join that namespace. If an existing network namespace is not specified but CLONE_NEWNET is,
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// the container will be spawned with a new network namespace with no configuration. Omiting an
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// existing network namespace and the CLONE_NEWNET option in the container configuration will allow
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// the container to the the host's networking options and configuration.
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func ExecContainer(container *libcontainer.Container) (pid int, err error) {
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master, console, err := createMasterAndConsole()
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if err != nil {
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return -1, err
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}
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// we need CLONE_VFORK so we can wait on the child
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flag := uintptr(getNamespaceFlags(container.Namespaces) | CLONE_VFORK)
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command := exec.Command("nsinit", console)
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command.SysProcAttr = &syscall.SysProcAttr{
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Cloneflags: flag,
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}
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if err := command.Start(); err != nil {
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return -1, err
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}
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pid = command.Process.Pid
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go func() {
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if _, err := io.Copy(os.Stdout, master); err != nil {
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log.Println(err)
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}
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}()
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go func() {
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if _, err := io.Copy(master, os.Stdin); err != nil {
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log.Println(err)
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}
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}()
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term.SetRawTerminal(os.Stdin.Fd())
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if err := command.Wait(); err != nil {
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return pid, err
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}
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return pid, nil
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}
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func createMasterAndConsole() (*os.File, string, error) {
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master, err := os.OpenFile("/dev/ptmx", syscall.O_RDWR|syscall.O_NOCTTY|syscall.O_CLOEXEC, 0)
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if err != nil {
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return nil, "", err
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}
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console, err := system.Ptsname(master)
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if err != nil {
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return nil, "", err
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}
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if err := system.Unlockpt(master); err != nil {
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return nil, "", err
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}
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return master, console, nil
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}
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