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+/*
+ * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
+ * Copyright (c) 1997 by Silicon Graphics. All rights reserved.
+ * Copyright (c) 2000 by Hewlett-Packard Company. All rights reserved.
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose, provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ *
+ * Original author: Bill Janssen
+ * Heavily modified by Hans Boehm and others
+ */
+
+/*
+ * This used to be in dyn_load.c. It was extracted into a separate file
+ * to avoid having to link against libdl.{a,so} if the client doesn't call
+ * dlopen. -HB
+ */
+
+#include "private/gc_priv.h"
+
+# if defined(LINUX_THREADS) || defined(SOLARIS_THREADS) \
+ || defined(HPUX_THREADS) || defined(IRIX_THREADS)
+
+# if defined(dlopen) && !defined(GC_USE_LD_WRAP)
+ /* To support various threads pkgs, gc.h interposes on dlopen by */
+ /* defining "dlopen" to be "GC_dlopen", which is implemented below. */
+ /* However, both GC_FirstDLOpenedLinkMap() and GC_dlopen() use the */
+ /* real system dlopen() in their implementation. We first remove */
+ /* gc.h's dlopen definition and restore it later, after GC_dlopen(). */
+# undef dlopen
+# endif
+
+ /* Make sure we're not in the middle of a collection, and make */
+ /* sure we don't start any. Returns previous value of GC_dont_gc. */
+ /* This is invoked prior to a dlopen call to avoid synchronization */
+ /* issues. We can't just acquire the allocation lock, since startup */
+ /* code in dlopen may try to allocate. */
+ /* This solution risks heap growth in the presence of many dlopen */
+ /* calls in either a multithreaded environment, or if the library */
+ /* initialization code allocates substantial amounts of GC'ed memory. */
+ /* But I don't know of a better solution. */
+ /* This can still deadlock if the client explicitly starts a GC */
+ /* during the dlopen. He shouldn't do that. */
+ static GC_bool disable_gc_for_dlopen()
+ {
+ GC_bool result;
+ LOCK();
+ result = GC_dont_gc;
+ while (GC_incremental && GC_collection_in_progress()) {
+ GC_collect_a_little_inner(1000);
+ }
+ GC_dont_gc = TRUE;
+ UNLOCK();
+ return(result);
+ }
+
+ /* Redefine dlopen to guarantee mutual exclusion with */
+ /* GC_register_dynamic_libraries. */
+ /* Should probably happen for other operating systems, too. */
+
+#include <dlfcn.h>
+
+#ifdef GC_USE_LD_WRAP
+ void * __wrap_dlopen(const char *path, int mode)
+#else
+ void * GC_dlopen(path, mode)
+ GC_CONST char * path;
+ int mode;
+#endif
+{
+ void * result;
+ GC_bool dont_gc_save;
+
+# ifndef USE_PROC_FOR_LIBRARIES
+ dont_gc_save = disable_gc_for_dlopen();
+# endif
+# ifdef GC_USE_LD_WRAP
+ result = (void *)__real_dlopen(path, mode);
+# else
+ result = dlopen(path, mode);
+# endif
+# ifndef USE_PROC_FOR_LIBRARIES
+ GC_dont_gc = dont_gc_save;
+# endif
+ return(result);
+}
+# endif /* LINUX_THREADS || SOLARIS_THREADS || ... */
+
+
+