100 lines
1.9 KiB
Go
100 lines
1.9 KiB
Go
package reaper
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import (
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"bytes"
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"fmt"
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"os/exec"
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"sync"
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"github.com/docker/containerd/utils"
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)
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// Reap should be called when the process receives an SIGCHLD. Reap will reap
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// all exited processes and close their wait channels
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func Reap() error {
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exits, err := utils.Reap(false)
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for _, e := range exits {
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Default.mu.Lock()
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c, ok := Default.cmds[e.Pid]
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Default.mu.Unlock()
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if !ok {
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continue
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}
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// after we get an exit, call wait on the go process to make sure all
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// pipes are closed and finalizers are run on the process
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c.c.Wait()
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c.exitCh <- e.Status
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Default.mu.Lock()
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delete(Default.cmds, e.Pid)
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Default.mu.Unlock()
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}
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return err
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}
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var Default = &Monitor{
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cmds: make(map[int]*cmd),
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}
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type Monitor struct {
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mu sync.Mutex
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cmds map[int]*cmd
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}
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func (m *Monitor) Output(c *exec.Cmd) ([]byte, error) {
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var b bytes.Buffer
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c.Stdout = &b
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if err := m.Run(c); err != nil {
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return nil, err
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}
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return b.Bytes(), nil
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}
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func (m *Monitor) CombinedOutput(c *exec.Cmd) ([]byte, error) {
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var b bytes.Buffer
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c.Stdout = &b
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c.Stderr = &b
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if err := m.Run(c); err != nil {
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return nil, err
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}
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return b.Bytes(), nil
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}
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// Start starts the command a registers the process with the reaper
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func (m *Monitor) Start(c *exec.Cmd) error {
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rc := &cmd{
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c: c,
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exitCh: make(chan int, 1),
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}
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// make sure we register the command first before starting the process
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m.mu.Lock()
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// start the process
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if err := rc.c.Start(); err != nil {
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m.mu.Unlock()
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return err
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}
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m.cmds[rc.c.Process.Pid] = rc
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m.mu.Unlock()
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return nil
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}
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// Run runs and waits for the command to finish
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func (m *Monitor) Run(c *exec.Cmd) error {
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if err := m.Start(c); err != nil {
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return err
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}
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_, err := m.Wait(c)
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return err
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}
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func (m *Monitor) Wait(c *exec.Cmd) (int, error) {
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rc, ok := m.cmds[c.Process.Pid]
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if !ok {
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return 255, fmt.Errorf("process does not exist")
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}
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return <-rc.exitCh, nil
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}
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type cmd struct {
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c *exec.Cmd
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exitCh chan int
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}
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