72 lines
1.4 KiB
Go
72 lines
1.4 KiB
Go
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package nsinit
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import (
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"encoding/json"
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"fmt"
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"github.com/dotcloud/docker/pkg/libcontainer"
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"io/ioutil"
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"os"
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)
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// SyncPipe allows communication to and from the child processes
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// to it's parent and allows the two independent processes to
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// syncronize their state.
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type SyncPipe struct {
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parent, child *os.File
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}
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func NewSyncPipe() (s *SyncPipe, err error) {
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s = &SyncPipe{}
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s.child, s.parent, err = os.Pipe()
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if err != nil {
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return nil, err
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}
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return s, nil
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}
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func NewSyncPipeFromFd(parendFd, childFd uintptr) (*SyncPipe, error) {
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s := &SyncPipe{}
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if parendFd > 0 {
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s.parent = os.NewFile(parendFd, "parendPipe")
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} else if childFd > 0 {
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s.child = os.NewFile(childFd, "childPipe")
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} else {
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return nil, fmt.Errorf("no valid sync pipe fd specified")
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}
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return s, nil
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}
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func (s *SyncPipe) SendToChild(context libcontainer.Context) error {
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data, err := json.Marshal(context)
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if err != nil {
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return err
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}
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s.parent.Write(data)
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return nil
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}
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func (s *SyncPipe) ReadFromParent() (libcontainer.Context, error) {
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data, err := ioutil.ReadAll(s.child)
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if err != nil {
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return nil, fmt.Errorf("error reading from sync pipe %s", err)
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}
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var context libcontainer.Context
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if len(data) > 0 {
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if err := json.Unmarshal(data, &context); err != nil {
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return nil, err
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}
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}
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return context, nil
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}
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func (s *SyncPipe) Close() error {
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if s.parent != nil {
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s.parent.Close()
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}
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if s.child != nil {
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s.child.Close()
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}
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return nil
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}
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