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Add comments to many functions

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Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
This commit is contained in:
Michael Crosby 2014-02-19 22:43:40 -08:00
parent ca0e7f087c
commit c20c1dfb04
10 changed files with 97 additions and 45 deletions
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23
libcontainer/nsinit/exec.go
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@ -38,7 +38,7 @@ func execCommand(container *libcontainer.Container, args []string) (int, error)
defer deletePidFile()
if container.Network != nil {
vethPair, err := setupVeth(container.Network.Bridge, command.Process.Pid)
vethPair, err := initializeContainerVeth(container.Network.Bridge, command.Process.Pid)
if err != nil {
return -1, err
}
@ -63,14 +63,21 @@ func execCommand(container *libcontainer.Container, args []string) (int, error)
return command.ProcessState.Sys().(syscall.WaitStatus).ExitStatus(), nil
}
// sendVethName writes the veth pair name to the child's stdin then closes the
// pipe so that the child stops waiting for more data
func sendVethName(name string, pipe io.WriteCloser) {
// write the veth pair name to the child's stdin then close the
// pipe so that the child stops waiting
fmt.Fprint(pipe, name)
pipe.Close()
}
func setupVeth(bridge string, nspid int) (string, error) {
// initializeContainerVeth will create a veth pair and setup the host's
// side of the pair by setting the specified bridge as the master and bringing
// up the interface.
//
// Then will with set the other side of the veth pair into the container's namespaced
// using the pid and returns the veth's interface name to provide to the container to
// finish setting up the interface inside the namespace
func initializeContainerVeth(bridge string, nspid int) (string, error) {
name1, name2, err := createVethPair()
if err != nil {
return "", err
@ -98,6 +105,8 @@ func setupWindow(master *os.File) (*term.State, error) {
return term.SetRawTerminal(os.Stdin.Fd())
}
// createMasterAndConsole will open /dev/ptmx on the host and retreive the
// pts name for use as the pty slave inside the container
func createMasterAndConsole() (*os.File, string, error) {
master, err := os.OpenFile("/dev/ptmx", syscall.O_RDWR|syscall.O_NOCTTY|syscall.O_CLOEXEC, 0)
if err != nil {
@ -113,6 +122,8 @@ func createMasterAndConsole() (*os.File, string, error) {
return master, console, nil
}
// createVethPair will automatically generage two random names for
// the veth pair and ensure that they have been created
func createVethPair() (name1 string, name2 string, err error) {
name1, err = utils.GenerateRandomName("dock", 4)
if err != nil {
@ -128,6 +139,7 @@ func createVethPair() (name1 string, name2 string, err error) {
return
}
// writePidFile writes the namespaced processes pid to .nspid in the rootfs for the container
func writePidFile(command *exec.Cmd) error {
return ioutil.WriteFile(".nspid", []byte(fmt.Sprint(command.Process.Pid)), 0655)
}
@ -136,6 +148,9 @@ func deletePidFile() error {
return os.Remove(".nspid")
}
// 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{"init", console}, args...)...)
command.SysProcAttr = &syscall.SysProcAttr{