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Use a custom pipe instead of stdin for sync net namespace

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Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume.charmes@docker.com> (github: creack)
This commit is contained in:
Guillaume J. Charmes 2014-02-20 17:58:13 -08:00 • committed by Michael Crosby
parent 3677967f4e
commit b2e01cbe8c
3 changed files with 19 additions and 11 deletions
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16
libcontainer/nsinit/exec.go
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@ -22,16 +22,20 @@ func execCommand(container *libcontainer.Container, args []string) (int, error)
return -1, err
}
command := createCommand(container, console, args)
// create a pipe so that we can syncronize with the namespaced process and
// pass the veth name to the child
inPipe, err := command.StdinPipe()
r, w, err := os.Pipe()
if err != nil {
return -1, err
}
system.UsetCloseOnExec(r.Fd())
command := createCommand(container, console, r.Fd(), args)
if err := command.Start(); err != nil {
return -1, err
}
if err := writePidFile(command); err != nil {
command.Process.Kill()
return -1, err
@ -52,11 +56,11 @@ func execCommand(container *libcontainer.Container, args []string) (int, error)
if err != nil {
return -1, err
}
sendVethName(vethPair, inPipe)
sendVethName(vethPair, w)
}
// Sync with child
inPipe.Close()
w.Close()
go io.Copy(os.Stdout, master)
go io.Copy(master, os.Stdin)
@ -163,8 +167,8 @@ func deletePidFile() error {
// createCommand 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 createCommand(container *libcontainer.Container, console string, args []string) *exec.Cmd {
command := exec.Command("nsinit", append([]string{"-console", console, "init"}, args...)...)
func createCommand(container *libcontainer.Container, console string, pipe uintptr, args []string) *exec.Cmd {
command := exec.Command("nsinit", append([]string{"-console", console, "-pipe", fmt.Sprint(pipe), "init"}, args...)...)
command.SysProcAttr = &syscall.SysProcAttr{
Cloneflags: uintptr(getNamespaceFlags(container.Namespaces)),
}