Allow more than one cleanup handler

cmd/restic/cleanup.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+
+	"github.com/restic/restic/debug"
+)
+
+var cleanupHandlers struct {
+	sync.Mutex
+	list []func() error
+}
+
+var stderr = os.Stderr
+
+func init() {
+	c := make(chan os.Signal)
+	signal.Notify(c, syscall.SIGINT)
+
+	go CleanupHandler(c)
+}
+
+// AddCleanupHandler adds the function f to the list of cleanup handlers so
+// that it is executed when all the cleanup handlers are run, e.g. when SIGINT
+// is received.
+func AddCleanupHandler(f func() error) {
+	cleanupHandlers.Lock()
+	defer cleanupHandlers.Unlock()
+
+	cleanupHandlers.list = append(cleanupHandlers.list, f)
+}
+
+// RunCleanupHandlers runs all registered cleanup handlers
+func RunCleanupHandlers() {
+	cleanupHandlers.Lock()
+	defer cleanupHandlers.Unlock()
+
+	for _, f := range cleanupHandlers.list {
+		err := f()
+		if err != nil {
+			fmt.Fprintf(stderr, "error in cleanup handler: %v\n", err)
+		}
+	}
+}
+
+// CleanupHandler handles the SIGINT signal.
+func CleanupHandler(c <-chan os.Signal) {
+	for s := range c {
+		debug.Log("CleanupHandler", "signal %v received, cleaning up", s)
+		fmt.Println("\x1b[2KInterrupt received, cleaning up")
+		RunCleanupHandlers()
+		fmt.Println("exiting")
+		os.Exit(0)
+	}
+}

cmd/restic/lock.go

@@ -3,9 +3,7 @@ package main
 import (
 	"fmt"
 	"os"
-	"os/signal"
 	"sync"
-	"syscall"
 	"time"
 
 	"github.com/restic/restic"
@@ -123,19 +121,5 @@ func unlockAll() error {
 }
 
 func init() {
-	c := make(chan os.Signal)
+	AddCleanupHandler(unlockAll)
-	signal.Notify(c, syscall.SIGINT)
-
-	go CleanupHandler(c)
-}
-
-// CleanupHandler handles the SIGINT signal.
-func CleanupHandler(c <-chan os.Signal) {
-	for s := range c {
-		debug.Log("CleanupHandler", "signal %v received, cleaning up", s)
-		fmt.Println("\x1b[2KInterrupt received, cleaning up")
-		unlockAll()
-		fmt.Println("exiting")
-		os.Exit(0)
-	}
 }