From 2ead86a27feba4a3da8339570baf2625757dbbb8 Mon Sep 17 00:00:00 2001
From: JustVugg <JustVugg@users.noreply.github.com>
Date: Tue, 14 Jul 2026 18:15:29 +0200
Subject: [PATCH] =?UTF-8?q?serve=20mux:=20fix=20Windows=20request=20dispat?=
 =?UTF-8?q?ch=20=E2=80=94=20BINARY-mode=20stdin/stdout=20+=20PeekNamedPipe?=
 =?UTF-8?q?-only=20polling=20(fixes=20#195)?=
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Two Windows-only bugs in run_serve_mux left the gateway hanging after READY:
1. No _setmode(_O_BINARY): the CRT collapsed CRLF inside fread() payloads (waits
   forever for missing bytes) and expanded LF in the READY/STAT sentinels.
2. WaitForSingleObject on an anonymous pipe is undefined (always-signaled or
   WAIT_FAILED) and PeekNamedPipe fails on file/console handles, so the dispatch
   gate never opened. New rule: idle -> block in getline (POSIX select(NULL)
   semantics); active -> PeekNamedPipe poll.

Reproduced and verified on real Windows via MinGW cross-compile + WSL interop:
old binary writes READY (with CRLF corruption) then hangs forever on a crafted
SUBMIT frame; fixed binary answers DONE + STAT and exits cleanly. Linux path
untouched (0 warnings, oracle-exact).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 c/glm.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/c/glm.c b/c/glm.c
index d6e5716..561d410 100644
--- a/c/glm.c
+++ b/c/glm.c
@@ -3418,6 +3418,14 @@ static void run_serve_mux(Model *m, const char *snap){
     KVState *initial=m->kv; free(initial->kv_start); free(initial);
     ServeCtx *ctx=calloc(nctx,sizeof(*ctx)); ServeReq *req=calloc(nctx,sizeof(*req));
     for(int i=0;i<nctx;i++) serve_ctx_init(m,&ctx[i],snap,i,maxctx);
+#ifdef _WIN32
+    /* Same byte-exact protocol as run_serve: in TEXT mode the CRT collapses CRLF in
+     * fread() payloads (waits forever for the missing bytes) and expands LF on the
+     * way out (corrupting the READY/STAT sentinels). BINARY on both ends. (#195) */
+    _setmode(_fileno(stdin),  _O_BINARY);
+    _setmode(_fileno(stdout), _O_BINARY);
+    setvbuf(stdout, NULL, _IONBF, 0);
+#endif
     setvbuf(stdin,NULL,_IONBF,0);
     printf("\x01\x01READY\x01\x01\nSTAT 0 0.00 0.0 %.2f\n",rss_gb()); fflush(stdout);
     hwinfo_emit(m);
@@ -3441,16 +3449,16 @@ static void run_serve_mux(Model *m, const char *snap){
 #elif defined(_WIN32)
             HANDLE ih=(HANDLE)_get_osfhandle(_fileno(stdin));
             DWORD avail=0;
-            /* WaitForSingleObject(handle, 0) is non-blocking and works on both
-             * pipe and console handles; for pipes PeekNamedPipe gives the byte
-             * count. Either returns "data is there right now". When a decode
-             * is active we poll (timeout 0); when idle we block until input. */
-            if(active){
-                ready=(WaitForSingleObject(ih,0)==WAIT_OBJECT_0)?1:0;
-            } else {
-                ready=(WaitForSingleObject(ih,INFINITE)==WAIT_OBJECT_0)?1:0;
-            }
-            if(ready && PeekNamedPipe(ih,NULL,0,NULL,&avail,NULL) && avail>0)
+            /* Anonymous pipes are NOT waitable objects: WaitForSingleObject on them is
+             * undefined (always-signaled or WAIT_FAILED), and PeekNamedPipe fails on
+             * file/console handles — the old gate never dispatched (#195). New rule:
+             * idle -> block in getline() inside mux_submit (same semantics as the
+             * POSIX select(NULL)); active -> poll the pipe with PeekNamedPipe, and on
+             * non-pipe stdin just defer submits until the batch finishes. */
+            if(eof) ready=0;
+            else if(!active) ready=1;
+            else ready=(PeekNamedPipe(ih,NULL,0,NULL,&avail,NULL) && avail>0)?1:0;
+            if(ready)
 #endif
                 if(mux_submit(m,&T,ctx,req,nctx,maxctx,eos)<0) eof=1;
         }