101 lines
3.8 KiB
C
101 lines
3.8 KiB
C
/*
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* Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
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* Copyright (c) 1997 by Silicon Graphics. All rights reserved.
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* Copyright (c) 2000 by Hewlett-Packard Company. All rights reserved.
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*
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* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
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* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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*
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* Permission is hereby granted to use or copy this program
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* for any purpose, provided the above notices are retained on all copies.
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* Permission to modify the code and to distribute modified code is granted,
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* provided the above notices are retained, and a notice that the code was
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* modified is included with the above copyright notice.
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*/
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#include "private/gc_priv.h"
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/* This used to be in dyn_load.c. It was extracted into a separate */
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/* file to avoid having to link against libdl.{a,so} if the client */
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/* doesn't call dlopen. Of course this fails if the collector is in */
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/* a dynamic library. -HB */
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#if defined(GC_PTHREADS) && !defined(GC_NO_DLOPEN)
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#undef GC_MUST_RESTORE_REDEFINED_DLOPEN
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#if defined(dlopen) && !defined(GC_USE_LD_WRAP)
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/* To support various threads pkgs, gc.h interposes on dlopen by */
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/* defining "dlopen" to be "GC_dlopen", which is implemented below. */
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/* However, both GC_FirstDLOpenedLinkMap() and GC_dlopen() use the */
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/* real system dlopen() in their implementation. We first remove */
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/* gc.h's dlopen definition and restore it later, after GC_dlopen(). */
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# undef dlopen
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# define GC_MUST_RESTORE_REDEFINED_DLOPEN
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#endif
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/* Make sure we're not in the middle of a collection, and make sure we */
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/* don't start any. This is invoked prior to a dlopen call to avoid */
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/* synchronization issues. We can't just acquire the allocation lock, */
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/* since startup code in dlopen may try to allocate. This solution */
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/* risks heap growth (or, even, heap overflow) in the presence of many */
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/* dlopen calls in either a multi-threaded environment, or if the */
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/* library initialization code allocates substantial amounts of GC'ed */
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/* memory. */
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#ifndef USE_PROC_FOR_LIBRARIES
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static void disable_gc_for_dlopen(void)
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{
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DCL_LOCK_STATE;
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LOCK();
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while (GC_incremental && GC_collection_in_progress()) {
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GC_collect_a_little_inner(1000);
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}
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++GC_dont_gc;
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UNLOCK();
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}
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#endif
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/* Redefine dlopen to guarantee mutual exclusion with */
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/* GC_register_dynamic_libraries. Should probably happen for */
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/* other operating systems, too. */
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/* This is similar to WRAP/REAL_FUNC() in pthread_support.c. */
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#ifdef GC_USE_LD_WRAP
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# define WRAP_DLFUNC(f) __wrap_##f
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# define REAL_DLFUNC(f) __real_##f
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void * REAL_DLFUNC(dlopen)(const char *, int);
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#else
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# define WRAP_DLFUNC(f) GC_##f
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# define REAL_DLFUNC(f) f
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#endif
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GC_API void * WRAP_DLFUNC(dlopen)(const char *path, int mode)
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{
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void * result;
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# ifndef USE_PROC_FOR_LIBRARIES
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/* Disable collections. This solution risks heap growth (or, */
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/* even, heap overflow) but there seems no better solutions. */
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disable_gc_for_dlopen();
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# endif
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result = REAL_DLFUNC(dlopen)(path, mode);
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# ifndef USE_PROC_FOR_LIBRARIES
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GC_enable(); /* undoes disable_gc_for_dlopen */
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# endif
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return(result);
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}
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#ifdef GC_USE_LD_WRAP
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/* Define GC_ function as an alias for the plain one, which will be */
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/* intercepted. This allows files which include gc.h, and hence */
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/* generate references to the GC_ symbol, to see the right symbol. */
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GC_API void *GC_dlopen(const char *path, int mode)
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{
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return dlopen(path, mode);
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}
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#endif /* GC_USE_LD_WRAP */
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#ifdef GC_MUST_RESTORE_REDEFINED_DLOPEN
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# define dlopen GC_dlopen
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#endif
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#endif /* GC_PTHREADS && !GC_NO_DLOPEN */
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