81 lines
2.1 KiB
Go
81 lines
2.1 KiB
Go
// +build linux
|
|
|
|
package main
|
|
|
|
import (
|
|
"os"
|
|
"os/signal"
|
|
"syscall"
|
|
|
|
"github.com/Sirupsen/logrus"
|
|
"github.com/docker/containerd"
|
|
"github.com/opencontainers/runc/libcontainer/utils"
|
|
)
|
|
|
|
// http://man7.org/linux/man-pages/man2/prctl.2.html
|
|
//
|
|
// If arg2 is nonzero, set the "child subreaper" attribute of the
|
|
// calling process; if arg2 is zero, unset the attribute. When a
|
|
// process is marked as a child subreaper, all of the children
|
|
// that it creates, and their descendants, will be marked as
|
|
// having a subreaper. In effect, a subreaper fulfills the role
|
|
// of init(1) for its descendant processes. Upon termination of
|
|
// a process that is orphaned (i.e., its immediate parent has
|
|
// already terminated) and marked as having a subreaper, the
|
|
// nearest still living ancestor subreaper will receive a SIGCHLD
|
|
// signal and be able to wait(2) on the process to discover its
|
|
// termination status.
|
|
const PR_SET_CHILD_SUBREAPER = 36
|
|
|
|
func startSignalHandler(supervisor *containerd.Supervisor, bufferSize int) {
|
|
logrus.Debug("containerd: starting signal handler")
|
|
signals := make(chan os.Signal, bufferSize)
|
|
signal.Notify(signals)
|
|
for s := range signals {
|
|
switch s {
|
|
case syscall.SIGTERM, syscall.SIGINT:
|
|
supervisor.Stop(signals)
|
|
case syscall.SIGCHLD:
|
|
exits, err := reap()
|
|
if err != nil {
|
|
logrus.WithField("error", err).Error("containerd: reaping child processes")
|
|
}
|
|
for _, e := range exits {
|
|
supervisor.SendEvent(e)
|
|
}
|
|
}
|
|
}
|
|
supervisor.Close()
|
|
os.Exit(0)
|
|
}
|
|
|
|
func reap() (exits []*containerd.Event, err error) {
|
|
var (
|
|
ws syscall.WaitStatus
|
|
rus syscall.Rusage
|
|
)
|
|
for {
|
|
pid, err := syscall.Wait4(-1, &ws, syscall.WNOHANG, &rus)
|
|
if err != nil {
|
|
if err == syscall.ECHILD {
|
|
return exits, nil
|
|
}
|
|
return exits, err
|
|
}
|
|
if pid <= 0 {
|
|
return exits, nil
|
|
}
|
|
e := containerd.NewEvent(containerd.ExitEventType)
|
|
e.Pid = pid
|
|
e.Status = utils.ExitStatus(ws)
|
|
exits = append(exits, e)
|
|
}
|
|
}
|
|
|
|
func setSubReaper() error {
|
|
if _, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, PR_SET_CHILD_SUBREAPER, 1, 0); err != 0 {
|
|
return err
|
|
}
|
|
return nil
|
|
}
|