win32: revisit how and when modules are enumerated

cisco · Nov 14, 2023 · f6c2f4f · f6c2f4f
1 parent 4c9f140
commit f6c2f4f
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Showing 2 changed files with 32 additions and 13 deletions.
diff --git a/c/foreign.c b/c/foreign.c
@@ -66,9 +66,6 @@ static ptr bvstring(const char *s);
 
 #ifdef LOAD_SHARED_OBJECT
 static void load_shared_object(const char *path);
-#ifdef WIN32
-HMODULE *base_modules;
-#endif /* WIN32 */
 #endif /* LOAD_SHARED_OBJECT */
 
 #ifdef HPUX
@@ -135,9 +132,15 @@ static ptr lookup_dynamic(const char *s, ptr tbl) {
 
 #ifdef WIN32
         if (!handle) {
-            for (HMODULE *m = base_modules; *m; ++m) {
-                value = dlsym(*m, s);
-                if (value != NULL) return addr_to_ptr(value);
+            HMODULE *modules = S_enum_process_modules();
+            if (modules) {
+                for (HMODULE *m = modules; *m; ++m) {
+                    value = dlsym(*m, s);
+                    if (value != NULL) break;
+                }
+                free(modules);
+                if (value != NULL)
+                    return addr_to_ptr(value);
             }
         } else
 #endif /* WIN32 */
@@ -349,9 +352,6 @@ void S_foreign_init(void) {
     S_protect(&S_foreign_dynamic);
     S_foreign_dynamic = Snil;
     Sforeign_symbol("(cs)load_shared_object", (void *)load_shared_object);
-#ifdef WIN32
-    base_modules = S_enum_process_modules();
-#endif /* WIN32 */
 #endif /* LOAD_SHARED_OBJECT */
 
     Sforeign_symbol("(cs)lookup_foreign_entry", (void *)lookup_foreign_entry);

diff --git a/c/windows.c b/c/windows.c
@@ -51,12 +51,31 @@ void *S_ntdlopen(const char *path) {
 }
 
 HMODULE *S_enum_process_modules(void) {
+    DWORD cur_num_bytes = 1024;
+    DWORD req_num_bytes;
+    HMODULE *modules = malloc(cur_num_bytes);
 
-    enum { MAX_MODULES = 256 };
+    if (!modules)
+        return NULL;
 
-    static HMODULE modules[MAX_MODULES + 1] = { NULL };
-    DWORD req_num_bytes;
-    EnumProcessModules(GetCurrentProcess(), modules, MAX_MODULES*sizeof(HMODULE), &req_num_bytes);
+    for (;;) {
+        if (!EnumProcessModules(GetCurrentProcess(), modules, cur_num_bytes, &req_num_bytes))
+            return NULL;
+        req_num_bytes += sizeof *modules; // for sentinel NULL value
+        if (req_num_bytes <= cur_num_bytes)
+            break;
+        HMODULE *new_mod = realloc(modules, req_num_bytes);
+        if (!new_mod) {
+            free(modules);
+            return NULL;
+        }
+
+        modules = new_mod;
+        cur_num_bytes = req_num_bytes;
+    }
+
+    const size_t numel = req_num_bytes/sizeof *modules;
+    modules[numel - 1] = NULL;
 
     return modules;
 }