Fix handler and systemd activation errors

On panic from handler: log warning and stack trace, report
InternalServerError to client

When using `podman system service` make determining the listening endpoint deterministic.

  // When determining _*THE*_ listening endpoint --
  // 1) User input wins always
  // 2) systemd socket activation
  // 3) rootless honors XDG_RUNTIME_DIR
  // 4) if varlink -- adapter.DefaultVarlinkAddress
  // 5) lastly adapter.DefaultAPIAddress

Fixes #5150
Fixes #5151

Signed-off-by: Jhon Honce <jhonce@redhat.com>

1 files changed, 36 insertions, 16 deletions

diff --git a/pkg/api/server/handler_api.go b/pkg/api/server/handler_api.go
index 4b93998ee..30a1680c9 100644
--- a/pkg/api/server/handler_api.go
+++ b/pkg/api/server/handler_api.go
@@ -2,32 +2,52 @@ package server
 
 import (
 	"context"
+	"fmt"
 	"net/http"
+	"runtime"
 
+	"github.com/containers/libpod/pkg/api/handlers/utils"
 	log "github.com/sirupsen/logrus"
 )
 
 // APIHandler is a wrapper to enhance HandlerFunc's and remove redundant code
-func APIHandler(ctx context.Context, h http.HandlerFunc) http.HandlerFunc {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		log.Debugf("APIHandler -- Method: %s URL: %s", r.Method, r.URL.String())
-		if err := r.ParseForm(); err != nil {
-			log.Infof("Failed Request: unable to parse form: %q", err)
-		}
+func (s *APIServer) APIHandler(h http.HandlerFunc) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		// http.Server hides panics, we want to see them and fix the cause.
+		defer func() {
+			err := recover()
+			if err != nil {
+				buf := make([]byte, 1<<20)
+				n := runtime.Stack(buf, true)
+				log.Warnf("Recovering from podman handler panic: %v, %s", err, buf[:n])
+				// Try to inform client things went south... won't work if handler already started writing response body
+				utils.InternalServerError(w, fmt.Errorf("%v", err))
+			}
+		}()
+
+		// Wrapper to hide some boiler plate
+		fn := func(w http.ResponseWriter, r *http.Request) {
+			// Connection counting, ugh.  Needed to support the sliding window for idle checking.
+			s.ConnectionCh <- EnterHandler
+			defer func() { s.ConnectionCh <- ExitHandler }()
+
+			log.Debugf("APIHandler -- Method: %s URL: %s (conn %d/%d)",
+				r.Method, r.URL.String(), s.ActiveConnections, s.TotalConnections)
 
-		// TODO: Use ConnContext when ported to go 1.13
-		c := context.WithValue(r.Context(), "decoder", ctx.Value("decoder"))
-		c = context.WithValue(c, "runtime", ctx.Value("runtime"))
-		c = context.WithValue(c, "shutdownFunc", ctx.Value("shutdownFunc"))
-		r = r.WithContext(c)
+			if err := r.ParseForm(); err != nil {
+				log.Infof("Failed Request: unable to parse form: %q", err)
+			}
 
-		h(w, r)
+			// TODO: Use r.ConnContext when ported to go 1.13
+			c := context.WithValue(r.Context(), "decoder", s.Decoder)
+			c = context.WithValue(c, "runtime", s.Runtime)
+			c = context.WithValue(c, "shutdownFunc", s.Shutdown)
+			r = r.WithContext(c)
 
-		shutdownFunc := r.Context().Value("shutdownFunc").(func() error)
-		if err := shutdownFunc(); err != nil {
-			log.Errorf("Failed to shutdown Server in APIHandler(): %s", err.Error())
+			h(w, r)
 		}
-	})
+		fn(w, r)
+	}
 }
 
 // VersionedPath prepends the version parsing code