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-rw-r--r--libpod/shutdown/handler.go105
1 files changed, 105 insertions, 0 deletions
diff --git a/libpod/shutdown/handler.go b/libpod/shutdown/handler.go
new file mode 100644
index 000000000..79f236ab6
--- /dev/null
+++ b/libpod/shutdown/handler.go
@@ -0,0 +1,105 @@
+package shutdown
+
+import (
+ "os"
+ "os/signal"
+ "sync"
+ "syscall"
+
+ "github.com/pkg/errors"
+ "github.com/sirupsen/logrus"
+)
+
+var (
+ stopped bool
+ sigChan chan os.Signal
+ cancelChan chan bool
+ handlers map[string]func() error
+ shutdownInhibit sync.RWMutex
+)
+
+// Start begins handling SIGTERM and SIGINT and will run the given on-signal
+// handlers when one is called. This can be cancelled by calling Stop().
+func Start() error {
+ if sigChan != nil && !stopped {
+ // Already running, do nothing.
+ return nil
+ }
+
+ sigChan = make(chan os.Signal, 1)
+ cancelChan = make(chan bool, 1)
+ stopped = false
+
+ signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+
+ go func() {
+ select {
+ case <-cancelChan:
+ signal.Stop(sigChan)
+ close(sigChan)
+ close(cancelChan)
+ stopped = true
+ return
+ case sig := <-sigChan:
+ logrus.Infof("Received shutdown signal %v, terminating!", sig)
+ shutdownInhibit.Lock()
+ for name, handler := range handlers {
+ logrus.Infof("Invoking shutdown handler %s", name)
+ if err := handler(); err != nil {
+ logrus.Errorf("Error running shutdown handler %s: %v", name, err)
+ }
+ }
+ shutdownInhibit.Unlock()
+ return
+ }
+ }()
+
+ return nil
+}
+
+// Stop the shutdown signal handler.
+func Stop() error {
+ if cancelChan == nil {
+ return errors.New("shutdown signal handler has not yet been started")
+ }
+ if stopped {
+ return nil
+ }
+
+ cancelChan <- true
+
+ return nil
+}
+
+// Temporarily inhibit signals from shutting down Libpod.
+func Inhibit() {
+ shutdownInhibit.RLock()
+}
+
+// Stop inhibiting signals from shutting down Libpod.
+func Uninhibit() {
+ shutdownInhibit.RUnlock()
+}
+
+// Register registers a function that will be executed when Podman is terminated
+// by a signal.
+func Register(name string, handler func() error) error {
+ if _, ok := handlers[name]; ok {
+ return errors.Errorf("handler with name %s already exists", name)
+ }
+
+ handlers[name] = handler
+
+ return nil
+}
+
+// Unregister un-registers a given shutdown handler.
+func Unregister(name string) error {
+ if _, ok := handlers[name]; !ok {
+ return errors.Errorf("no handler with name %s found", name)
+ }
+
+ delete(handlers, name)
+
+ return nil
+}