Fix `system service` panic from early hangup in events

We weren't actually halting the goroutine that sent events, so it
would continue sending even when the channel closed (the most
notable cause being early hangup - e.g. Control-c on a curl
session). Use a context to cancel the events goroutine and stop
sending events.

Fixes #6805

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

5 files changed, 12 insertions, 6 deletions

diff --git a/pkg/api/handlers/compat/events.go b/pkg/api/handlers/compat/events.go
index 215d7c972..5acc94153 100644
--- a/pkg/api/handlers/compat/events.go
+++ b/pkg/api/handlers/compat/events.go
@@ -1,6 +1,7 @@
 package compat
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 
@@ -45,13 +46,15 @@ func GetEvents(w http.ResponseWriter, r *http.Request) {
 		fromStart = true
 	}
 
+	eventCtx, eventCancel := context.WithCancel(r.Context())
 	eventChannel := make(chan *events.Event)
 	go func() {
 		readOpts := events.ReadOptions{FromStart: fromStart, Stream: query.Stream, Filters: libpodFilters, EventChannel: eventChannel, Since: query.Since, Until: query.Until}
-		eventsError = runtime.Events(readOpts)
+		eventsError = runtime.Events(eventCtx, readOpts)
 	}()
 	if eventsError != nil {
 		utils.InternalServerError(w, eventsError)
+		eventCancel()
 		close(eventChannel)
 		return
 	}
@@ -59,6 +62,7 @@ func GetEvents(w http.ResponseWriter, r *http.Request) {
 	// If client disappears we need to stop listening for events
 	go func(done <-chan struct{}) {
 		<-done
+		eventCancel()
 		if _, ok := <-eventChannel; ok {
 			close(eventChannel)
 		}
diff --git a/pkg/domain/infra/abi/containers.go b/pkg/domain/infra/abi/containers.go
index d5dce0b0f..596fc2cc1 100644
--- a/pkg/domain/infra/abi/containers.go
+++ b/pkg/domain/infra/abi/containers.go
@@ -741,7 +741,7 @@ func (ic *ContainerEngine) ContainerStart(ctx context.Context, namesOrIds []stri
 			if ecode, err := ctr.Wait(); err != nil {
 				if errors.Cause(err) == define.ErrNoSuchCtr {
 					// Check events
-					event, err := ic.Libpod.GetLastContainerEvent(ctr.ID(), events.Exited)
+					event, err := ic.Libpod.GetLastContainerEvent(ctx, ctr.ID(), events.Exited)
 					if err != nil {
 						logrus.Errorf("Cannot get exit code: %v", err)
 						exitCode = define.ExecErrorCodeNotFound
@@ -871,7 +871,7 @@ func (ic *ContainerEngine) ContainerRun(ctx context.Context, opts entities.Conta
 	if ecode, err := ctr.Wait(); err != nil {
 		if errors.Cause(err) == define.ErrNoSuchCtr {
 			// Check events
-			event, err := ic.Libpod.GetLastContainerEvent(ctr.ID(), events.Exited)
+			event, err := ic.Libpod.GetLastContainerEvent(ctx, ctr.ID(), events.Exited)
 			if err != nil {
 				logrus.Errorf("Cannot get exit code: %v", err)
 				report.ExitCode = define.ExecErrorCodeNotFound
diff --git a/pkg/domain/infra/abi/events.go b/pkg/domain/infra/abi/events.go
index 50d7727ce..7a8185445 100644
--- a/pkg/domain/infra/abi/events.go
+++ b/pkg/domain/infra/abi/events.go
@@ -9,5 +9,5 @@ import (
 
 func (ic *ContainerEngine) Events(ctx context.Context, opts entities.EventsOptions) error {
 	readOpts := events.ReadOptions{FromStart: opts.FromStart, Stream: opts.Stream, Filters: opts.Filter, EventChannel: opts.EventChan, Since: opts.Since, Until: opts.Until}
-	return ic.Libpod.Events(readOpts)
+	return ic.Libpod.Events(ctx, readOpts)
 }
diff --git a/pkg/varlinkapi/attach.go b/pkg/varlinkapi/attach.go
index 731d89b8f..8acf2a1b6 100644
--- a/pkg/varlinkapi/attach.go
+++ b/pkg/varlinkapi/attach.go
@@ -4,6 +4,7 @@ package varlinkapi
 
 import (
 	"bufio"
+	"context"
 	"io"
 
 	"github.com/containers/libpod/v2/libpod"
@@ -89,7 +90,7 @@ func (i *VarlinkAPI) Attach(call iopodman.VarlinkCall, name string, detachKeys s
 		if ecode, err := ctr.Wait(); err != nil {
 			if errors.Cause(err) == define.ErrNoSuchCtr {
 				// Check events
-				event, err := i.Runtime.GetLastContainerEvent(ctr.ID(), events.Exited)
+				event, err := i.Runtime.GetLastContainerEvent(context.Background(), ctr.ID(), events.Exited)
 				if err != nil {
 					logrus.Errorf("Cannot get exit code: %v", err)
 					exitCode = define.ExecErrorCodeNotFound
diff --git a/pkg/varlinkapi/events.go b/pkg/varlinkapi/events.go
index 2e468b706..910b64a57 100644
--- a/pkg/varlinkapi/events.go
+++ b/pkg/varlinkapi/events.go
@@ -3,6 +3,7 @@
 package varlinkapi
 
 import (
+	"context"
 	"time"
 
 	"github.com/containers/libpod/v2/libpod/events"
@@ -27,7 +28,7 @@ func (i *VarlinkAPI) GetEvents(call iopodman.VarlinkCall, filter []string, since
 	eventChannel := make(chan *events.Event)
 	go func() {
 		readOpts := events.ReadOptions{FromStart: fromStart, Stream: stream, Filters: filter, EventChannel: eventChannel}
-		eventsError = i.Runtime.Events(readOpts)
+		eventsError = i.Runtime.Events(context.Background(), readOpts)
 	}()
 	if eventsError != nil {
 		return call.ReplyErrorOccurred(eventsError.Error())