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gc_dlopen.c    90 lines (77 with data), 3.1 kB

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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. Of course this fails if the collector is in a dynamic
* library. -HB
*/
#include "private/gc_priv.h"
# if (defined(GC_PTHREADS) && !defined(GC_DARWIN_THREADS)) && !defined(GC_WIN32_PTHREADS)\
|| defined(GC_SOLARIS_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. */
static void disable_gc_for_dlopen()
{
LOCK();
while (GC_incremental && GC_collection_in_progress()) {
GC_collect_a_little_inner(1000);
}
++GC_dont_gc;
UNLOCK();
}
/* 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(const char *path, int mode)
#endif
{
void * result;
# ifndef USE_PROC_FOR_LIBRARIES
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_enable(); /* undoes disable_gc_for_dlopen */
# endif
return(result);
}
# endif /* GC_PTHREADS || GC_SOLARIS_THREADS ... */