From 5077dfea8e0b65c7092a7a697396092a28e23aae Mon Sep 17 00:00:00 2001
From: Levi Neely <lneely@pascom.net>
Date: Tue, 6 Oct 2026 13:50:58 +0200
Subject: [PATCH] server: fix event file fallthrough when fid lookup fails

If fidOK was false for the event file, we fell through to the
default stream handling path which doesn't work for events.
Now we return 'bad fid' error instead of falling through.
---
 cmd/olliesrv/server.go | 71 +++++++++++++++++++++---------------------
 1 file changed, 36 insertions(+), 35 deletions(-)

diff --git a/cmd/olliesrv/server.go b/cmd/olliesrv/server.go
index 392fbca..c1ac51c 100644
--- a/cmd/olliesrv/server.go
+++ b/cmd/olliesrv/server.go
@@ -606,46 +606,47 @@ func read(root *fs.Tree, cs *connState, fc *plan9.Fcall, ctx context.Context) *p
 			// lives until the client disconnects or clunks the fid
 			clientConnCtx := cs.ctx
 			cs.mu.RUnlock()
-			if fidOK {
+			if !fidOK {
+				return errFcall(fc, "bad fid")
+			}
+			f.mu.Lock()
+			filter := f.eventFilter
+			eventCh := f.eventCh
+			f.mu.Unlock()
+
+			// Create subscription on first read (filter defaults to "*" for all events)
+			if eventCh == nil {
+				if filter == "" {
+					filter = "*"
+				}
+				subCtx, cancel := context.WithCancel(clientConnCtx)
+				ch := session.SubscribeEventsFiltered(subCtx, filter)
 				f.mu.Lock()
-				filter := f.eventFilter
-				eventCh := f.eventCh
+				f.eventFilter = filter
+				f.eventCh = ch
+				f.eventCancel = cancel
 				f.mu.Unlock()
+				eventCh = ch
+			}
 
-				// Create subscription on first read (filter defaults to "*" for all events)
-				if eventCh == nil {
-					if filter == "" {
-						filter = "*"
-					}
-					subCtx, cancel := context.WithCancel(clientConnCtx)
-					ch := session.SubscribeEventsFiltered(subCtx, filter)
-					f.mu.Lock()
-					f.eventFilter = filter
-					f.eventCh = ch
-					f.eventCancel = cancel
-					f.mu.Unlock()
-					eventCh = ch
+			// Read from subscription — blocks until event arrives
+			select {
+			case ev, ok := <-eventCh:
+				if !ok {
+					return &plan9.Fcall{Type: plan9.Rread, Tag: fc.Tag, Count: 0}
 				}
-
-				// Read from subscription — blocks until event arrives
-				select {
-				case ev, ok := <-eventCh:
-					if !ok {
-						return &plan9.Fcall{Type: plan9.Rread, Tag: fc.Tag, Count: 0}
-					}
-					line := ev.Topic
-					if ev.Payload != "" {
-						line += " " + ev.Payload
-					}
-					content := []byte(line + "\n")
-					count := int(fc.Count)
-					if count > len(content) {
-						count = len(content)
-					}
-					return &plan9.Fcall{Type: plan9.Rread, Tag: fc.Tag, Count: uint32(count), Data: content[:count]}
-				case <-ctx.Done():
-					return errFcall(fc, "interrupted")
+				line := ev.Topic
+				if ev.Payload != "" {
+					line += " " + ev.Payload
 				}
+				content := []byte(line + "\n")
+				count := int(fc.Count)
+				if count > len(content) {
+					count = len(content)
+				}
+				return &plan9.Fcall{Type: plan9.Rread, Tag: fc.Tag, Count: uint32(count), Data: content[:count]}
+			case <-ctx.Done():
+				return errFcall(fc, "interrupted")
 			}
 		}