$NetBSD: patch-ak,v 1.3 2010/04/23 14:08:17 he Exp $

Prevent problem exposed by "library cloning", where the dlopen()-returned
handle is copied, causing dlclose() to be called twice with the same handle,
which in turn triggers a warning from ld.elf_so on NetBSD.  Ref.
http://trac.parrot.org/parrot/ticket/1340.

--- config/gen/platform/generic/dl.c.orig	2010-03-22 13:39:23.000000000 +0100
+++ config/gen/platform/generic/dl.c
@@ -22,11 +22,69 @@ Dynlib stuff
 */
 
 #ifdef PARROT_HAS_HEADER_DLFCN
+#  include <stddef.h>
+#  include <stdlib.h>
 #  include <dlfcn.h>
 #endif
 
 #define PARROT_DLOPEN_FLAGS RTLD_LAZY
 
+
+#ifdef PARROT_HAS_HEADER_DLFCN
+
+struct handle_entry {
+    void *handle;
+    struct handle_entry *next;
+};
+
+struct handle_entry *handle_list = NULL;
+
+static void
+push_handle_entry(void *handle)
+{
+    struct handle_entry *e;
+
+    e = (struct handle_entry *) malloc(sizeof(struct handle_entry));
+    if (!e) { return; }
+    e->handle = handle;
+    e->next = handle_list;
+    handle_list = e;
+}
+
+static void *
+find_handle_entry(void *handle)
+{
+    struct handle_entry *e;
+
+    for(e = handle_list; e; e = e->next) {
+	if (e->handle == handle)
+	    return handle;
+    }
+    return NULL;
+}
+
+static void
+remove_handle_entry(void *handle)
+{
+    struct handle_entry *cur, *prev, *p;
+
+    if (handle_list) {
+	if (handle_list->handle == handle) {
+	    p = handle_list;
+	    handle_list = p->next;
+	    free(p);
+	} else {
+	    for (cur = handle_list; cur; prev = cur, cur = cur->next) {
+		if (cur->handle == handle) {
+		    prev->next = cur->next;
+		    free(cur);
+		}
+	    }
+	}
+    }
+}
+#endif /* PARROT_HAS_HEADER_DLFCN */
+
 /*
 
 =item C<void * Parrot_dlopen(const char *filename, Parrot_dlopen_flags flags)>
@@ -39,8 +97,12 @@ void *
 Parrot_dlopen(const char *filename, Parrot_dlopen_flags flags)
 {
 #ifdef PARROT_HAS_HEADER_DLFCN
-    return dlopen(filename, PARROT_DLOPEN_FLAGS
-                    | ((flags & Parrot_dlopen_global_FLAG) ? RTLD_GLOBAL : 0));
+    void *h;
+
+    h = dlopen(filename, PARROT_DLOPEN_FLAGS
+	       | ((flags & Parrot_dlopen_global_FLAG) ? RTLD_GLOBAL : 0));
+    push_handle_entry(h);
+    return h;
 #else
     return 0;
 #endif
@@ -94,10 +156,15 @@ int
 Parrot_dlclose(void *handle)
 {
 #ifdef PARROT_HAS_HEADER_DLFCN
-    return dlclose(handle);
-#else
-    return -1;
+    int rv;
+
+    if (find_handle_entry(handle)) {
+	remove_handle_entry(handle);
+	rv = dlclose(handle);
+	return rv;
+    }
 #endif
+    return -1;
 }
 
 /*