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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.
*/
#include "private/gc_priv.h"
/* 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 */
#if defined(GC_PTHREADS) && !defined(GC_NO_DLOPEN)
#undef GC_MUST_RESTORE_REDEFINED_DLOPEN
#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
# define GC_MUST_RESTORE_REDEFINED_DLOPEN
#endif
/* Make sure we're not in the middle of a collection, and make sure we */
/* don't start any. 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 (or, even, heap overflow) in the presence of many */
/* dlopen calls in either a multi-threaded environment, or if the */
/* library initialization code allocates substantial amounts of GC'ed */
/* memory. */
#ifndef USE_PROC_FOR_LIBRARIES
static void disable_gc_for_dlopen(void)
{
DCL_LOCK_STATE;
LOCK();
while (GC_incremental && GC_collection_in_progress()) {
GC_collect_a_little_inner(1000);
}
++GC_dont_gc;
UNLOCK();
}
#endif
/* Redefine dlopen to guarantee mutual exclusion with */
/* GC_register_dynamic_libraries. Should probably happen for */
/* other operating systems, too. */
/* This is similar to WRAP/REAL_FUNC() in pthread_support.c. */
#ifdef GC_USE_LD_WRAP
# define WRAP_DLFUNC(f) __wrap_##f
# define REAL_DLFUNC(f) __real_##f
void * REAL_DLFUNC(dlopen)(const char *, int);
#else
# define WRAP_DLFUNC(f) GC_##f
# define REAL_DLFUNC(f) f
#endif
GC_API void * WRAP_DLFUNC(dlopen)(const char *path, int mode)
{
void * result;
# ifndef USE_PROC_FOR_LIBRARIES
/* Disable collections. This solution risks heap growth (or, */
/* even, heap overflow) but there seems no better solutions. */
disable_gc_for_dlopen();
# endif
result = REAL_DLFUNC(dlopen)(path, mode);
# ifndef USE_PROC_FOR_LIBRARIES
GC_enable(); /* undoes disable_gc_for_dlopen */
# endif
return(result);
}
#ifdef GC_USE_LD_WRAP
/* Define GC_ function as an alias for the plain one, which will be */
/* intercepted. This allows files which include gc.h, and hence */
/* generate references to the GC_ symbol, to see the right symbol. */
GC_API void *GC_dlopen(const char *path, int mode)
{
return dlopen(path, mode);
}
#endif /* GC_USE_LD_WRAP */
#ifdef GC_MUST_RESTORE_REDEFINED_DLOPEN
# define dlopen GC_dlopen
#endif
#endif /* GC_PTHREADS && !GC_NO_DLOPEN */