106 lines
1.8 KiB
Go
106 lines
1.8 KiB
Go
package syncpipe
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import (
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"encoding/json"
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"fmt"
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"io/ioutil"
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"os"
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"syscall"
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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 NewSyncPipeFromFd(parentFd, childFd uintptr) (*SyncPipe, error) {
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s := &SyncPipe{}
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if parentFd > 0 {
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s.parent = os.NewFile(parentFd, "parentPipe")
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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) Child() *os.File {
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return s.child
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}
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func (s *SyncPipe) Parent() *os.File {
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return s.parent
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}
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func (s *SyncPipe) SendToChild(v interface{}) error {
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data, err := json.Marshal(v)
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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 syscall.Shutdown(int(s.parent.Fd()), syscall.SHUT_WR)
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}
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func (s *SyncPipe) ReadFromChild() error {
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data, err := ioutil.ReadAll(s.parent)
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if err != nil {
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return err
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}
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if len(data) > 0 {
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return fmt.Errorf("%s", data)
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}
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return nil
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}
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func (s *SyncPipe) ReadFromParent(v interface{}) error {
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data, err := ioutil.ReadAll(s.child)
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if err != nil {
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return fmt.Errorf("error reading from sync pipe %s", err)
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}
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if len(data) > 0 {
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if err := json.Unmarshal(data, v); err != nil {
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return err
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}
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}
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return nil
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}
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func (s *SyncPipe) ReportChildError(err error) {
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// ensure that any data sent from the parent is consumed so it doesn't
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// receive ECONNRESET when the child writes to the pipe.
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ioutil.ReadAll(s.child)
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s.child.Write([]byte(err.Error()))
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s.CloseChild()
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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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func (s *SyncPipe) CloseChild() {
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if s.child != nil {
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s.child.Close()
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s.child = nil
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}
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}
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