From 1e594995292f4eb36e8afd42ed62389d7df95873 Mon Sep 17 00:00:00 2001
From: Scott Duensing <scott@duensing.com>
Date: Wed, 18 Mar 2026 01:27:38 -0500
Subject: [PATCH] dlopen edge case for non-multi-instance apps avoided.

---
 dvxshell/shellApp.c | 41 ++++++++++++++++++-----------------------
 1 file changed, 18 insertions(+), 23 deletions(-)

diff --git a/dvxshell/shellApp.c b/dvxshell/shellApp.c
index e849ffd..780e421 100644
--- a/dvxshell/shellApp.c
+++ b/dvxshell/shellApp.c
@@ -32,7 +32,7 @@ static void       appTaskWrapper(void *arg);
 static const char *baseName(const char *path);
 static void       cleanupTempFile(ShellAppT *app);
 static int32_t    copyFile(const char *src, const char *dst);
-static bool       isPathLoaded(const char *path);
+static ShellAppT *findLoadedPath(const char *path);
 static int32_t    makeTempPath(const char *origPath, int32_t id, char *out, int32_t outSize);
 void              shellAppInit(void);
 void              shellForceKillApp(AppContextT *ctx, ShellAppT *app);
@@ -135,15 +135,16 @@ static int32_t copyFile(const char *src, const char *dst) {
 }
 
 
-// Check if a DXE path is already loaded in any active slot.
-static bool isPathLoaded(const char *path) {
+// Find an active slot with the given DXE path. Returns the slot pointer,
+// or NULL if no running app was loaded from this path.
+static ShellAppT *findLoadedPath(const char *path) {
     for (int32_t i = 1; i < SHELL_MAX_APPS; i++) {
         if (sApps[i].state != AppStateFreeE && strcmp(sApps[i].path, path) == 0) {
-            return true;
+            return &sApps[i];
         }
     }
 
-    return false;
+    return NULL;
 }
 
 
@@ -264,28 +265,22 @@ int32_t shellLoadApp(AppContextT *ctx, const char *path) {
         return -1;
     }
 
-    // Check if this DXE is already loaded. If so, we need to inspect its
-    // descriptor to decide whether to allow a second instance.
+    // Check if this DXE is already loaded. If so, check whether the app
+    // allows multiple instances. We read the descriptor from the existing
+    // slot directly — no need to dlopen again.
     const char *loadPath  = path;
     char        tempPath[260] = {0};
+    ShellAppT  *existing = findLoadedPath(path);
 
-    if (isPathLoaded(path)) {
-        // Peek at the descriptor from the already-loaded module to check
-        // multiInstance. Since it's already loaded, dlopen returns the
-        // existing handle (cheap, no actual reload).
-        void *peek = dlopen(path, RTLD_GLOBAL);
+    if (existing) {
+        // Read multiInstance from the already-loaded descriptor
+        AppDescriptorT *existDesc = (AppDescriptorT *)dlsym(existing->dxeHandle, "_appDescriptor");
 
-        if (peek) {
-            AppDescriptorT *peekDesc = (AppDescriptorT *)dlsym(peek, "_appDescriptor");
-            bool allow = peekDesc && peekDesc->multiInstance;
-            dlclose(peek);
-
-            if (!allow) {
-                char msg[320];
-                snprintf(msg, sizeof(msg), "%s is already running.", baseName(path));
-                dvxMessageBox(ctx, "Error", msg, MB_OK | MB_ICONERROR);
-                return -1;
-            }
+        if (!existDesc || !existDesc->multiInstance) {
+            char msg[320];
+            snprintf(msg, sizeof(msg), "%s is already running.", baseName(path));
+            dvxMessageBox(ctx, "Error", msg, MB_OK | MB_ICONERROR);
+            return -1;
         }
 
         // Multi-instance allowed: copy to a temp file so dlopen gets