From f89a0057407edb0bfb757de8bbb601dd17fb6084 Mon Sep 17 00:00:00 2001
From: Emily Shepherd <emily@redcoat.dev>
Date: Tue, 6 Sep 2022 01:24:17 +0100
Subject: [PATCH] Cleanup Socket and Pidfile on exit

These were previously left intact, even when exiting gracefully. As the
daemon also fails if the socket already exists, it became the caller's
responsibilityto check for and cleanup old socket files when performing
graceful / deliberate restarts.

Signed-off-by: Emily Shepherd <emily@redcoat.dev>
---
 plugins/ipam/dhcp/daemon.go | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/plugins/ipam/dhcp/daemon.go b/plugins/ipam/dhcp/daemon.go
index b17a64614..a201f019a 100644
--- a/plugins/ipam/dhcp/daemon.go
+++ b/plugins/ipam/dhcp/daemon.go
@@ -15,6 +15,7 @@
 package main
 
 import (
+	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -23,9 +24,11 @@ import (
 	"net/http"
 	"net/rpc"
 	"os"
+	"os/signal"
 	"path/filepath"
 	"runtime"
 	"sync"
+	"syscall"
 	"time"
 
 	"github.com/containernetworking/cni/pkg/skel"
@@ -195,11 +198,27 @@ func runDaemon(
 		return fmt.Errorf("Error getting listener: %v", err)
 	}
 
+	srv := http.Server{}
+	exit := make(chan os.Signal, 1)
+	done := make(chan bool, 1)
+	signal.Notify(exit, os.Interrupt, syscall.SIGTERM)
+
+	go func() {
+		<-exit
+		srv.Shutdown(context.TODO())
+		os.Remove(hostPrefix + socketPath)
+		os.Remove(pidfilePath)
+
+		done <- true
+	}()
+
 	dhcp := newDHCP(dhcpClientTimeout, resendMax)
 	dhcp.hostNetnsPrefix = hostPrefix
 	dhcp.broadcast = broadcast
 	rpc.Register(dhcp)
 	rpc.HandleHTTP()
-	http.Serve(l, nil)
+	srv.Serve(l)
+
+	<-done
 	return nil
 }