github.com/docker/docker@v299999999.0.0-20200612211812-aaf470eca7b5+incompatible/daemon/kill.go (about) 1 package daemon // import "github.com/docker/docker/daemon" 2 3 import ( 4 "context" 5 "fmt" 6 "runtime" 7 "syscall" 8 "time" 9 10 containerpkg "github.com/docker/docker/container" 11 "github.com/docker/docker/errdefs" 12 libcontainerdtypes "github.com/docker/docker/libcontainerd/types" 13 "github.com/docker/docker/pkg/signal" 14 "github.com/pkg/errors" 15 "github.com/sirupsen/logrus" 16 ) 17 18 type errNoSuchProcess struct { 19 pid int 20 signal int 21 } 22 23 func (e errNoSuchProcess) Error() string { 24 return fmt.Sprintf("Cannot kill process (pid=%d) with signal %d: no such process.", e.pid, e.signal) 25 } 26 27 func (errNoSuchProcess) NotFound() {} 28 29 // isErrNoSuchProcess returns true if the error 30 // is an instance of errNoSuchProcess. 31 func isErrNoSuchProcess(err error) bool { 32 _, ok := err.(errNoSuchProcess) 33 return ok 34 } 35 36 // ContainerKill sends signal to the container 37 // If no signal is given (sig 0), then Kill with SIGKILL and wait 38 // for the container to exit. 39 // If a signal is given, then just send it to the container and return. 40 func (daemon *Daemon) ContainerKill(name string, sig uint64) error { 41 container, err := daemon.GetContainer(name) 42 if err != nil { 43 return err 44 } 45 46 if sig != 0 && !signal.ValidSignalForPlatform(syscall.Signal(sig)) { 47 return fmt.Errorf("The %s daemon does not support signal %d", runtime.GOOS, sig) 48 } 49 50 // If no signal is passed, or SIGKILL, perform regular Kill (SIGKILL + wait()) 51 if sig == 0 || syscall.Signal(sig) == syscall.SIGKILL { 52 return daemon.Kill(container) 53 } 54 return daemon.killWithSignal(container, int(sig)) 55 } 56 57 // killWithSignal sends the container the given signal. This wrapper for the 58 // host specific kill command prepares the container before attempting 59 // to send the signal. An error is returned if the container is paused 60 // or not running, or if there is a problem returned from the 61 // underlying kill command. 62 func (daemon *Daemon) killWithSignal(container *containerpkg.Container, sig int) error { 63 logrus.Debugf("Sending kill signal %d to container %s", sig, container.ID) 64 container.Lock() 65 defer container.Unlock() 66 67 if !container.Running { 68 return errNotRunning(container.ID) 69 } 70 71 var unpause bool 72 if container.Config.StopSignal != "" && syscall.Signal(sig) != syscall.SIGKILL { 73 containerStopSignal, err := signal.ParseSignal(container.Config.StopSignal) 74 if err != nil { 75 return err 76 } 77 if containerStopSignal == syscall.Signal(sig) { 78 container.ExitOnNext() 79 unpause = container.Paused 80 } 81 } else { 82 container.ExitOnNext() 83 unpause = container.Paused 84 } 85 86 if !daemon.IsShuttingDown() { 87 container.HasBeenManuallyStopped = true 88 container.CheckpointTo(daemon.containersReplica) 89 } 90 91 // if the container is currently restarting we do not need to send the signal 92 // to the process. Telling the monitor that it should exit on its next event 93 // loop is enough 94 if container.Restarting { 95 return nil 96 } 97 98 if err := daemon.kill(container, sig); err != nil { 99 if errdefs.IsNotFound(err) { 100 unpause = false 101 logrus.WithError(err).WithField("container", container.ID).WithField("action", "kill").Debug("container kill failed because of 'container not found' or 'no such process'") 102 } else { 103 return errors.Wrapf(err, "Cannot kill container %s", container.ID) 104 } 105 } 106 107 if unpause { 108 // above kill signal will be sent once resume is finished 109 if err := daemon.containerd.Resume(context.Background(), container.ID); err != nil { 110 logrus.Warnf("Cannot unpause container %s: %s", container.ID, err) 111 } 112 } 113 114 attributes := map[string]string{ 115 "signal": fmt.Sprintf("%d", sig), 116 } 117 daemon.LogContainerEventWithAttributes(container, "kill", attributes) 118 return nil 119 } 120 121 // Kill forcefully terminates a container. 122 func (daemon *Daemon) Kill(container *containerpkg.Container) error { 123 if !container.IsRunning() { 124 return errNotRunning(container.ID) 125 } 126 127 // 1. Send SIGKILL 128 if err := daemon.killPossiblyDeadProcess(container, int(syscall.SIGKILL)); err != nil { 129 // While normally we might "return err" here we're not going to 130 // because if we can't stop the container by this point then 131 // it's probably because it's already stopped. Meaning, between 132 // the time of the IsRunning() call above and now it stopped. 133 // Also, since the err return will be environment specific we can't 134 // look for any particular (common) error that would indicate 135 // that the process is already dead vs something else going wrong. 136 // So, instead we'll give it up to 2 more seconds to complete and if 137 // by that time the container is still running, then the error 138 // we got is probably valid and so we return it to the caller. 139 if isErrNoSuchProcess(err) { 140 return nil 141 } 142 143 ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second) 144 defer cancel() 145 146 if status := <-container.Wait(ctx, containerpkg.WaitConditionNotRunning); status.Err() != nil { 147 return err 148 } 149 } 150 151 // 2. Wait for the process to die, in last resort, try to kill the process directly 152 if err := killProcessDirectly(container); err != nil { 153 if isErrNoSuchProcess(err) { 154 return nil 155 } 156 return err 157 } 158 159 // Wait for exit with no timeout. 160 // Ignore returned status. 161 <-container.Wait(context.Background(), containerpkg.WaitConditionNotRunning) 162 163 return nil 164 } 165 166 // killPossibleDeadProcess is a wrapper around killSig() suppressing "no such process" error. 167 func (daemon *Daemon) killPossiblyDeadProcess(container *containerpkg.Container, sig int) error { 168 err := daemon.killWithSignal(container, sig) 169 if errdefs.IsNotFound(err) { 170 e := errNoSuchProcess{container.GetPID(), sig} 171 logrus.Debug(e) 172 return e 173 } 174 return err 175 } 176 177 func (daemon *Daemon) kill(c *containerpkg.Container, sig int) error { 178 return daemon.containerd.SignalProcess(context.Background(), c.ID, libcontainerdtypes.InitProcessName, sig) 179 }