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Annotation of OpenXM_contrib2/asir2000/gc/gc_dlopen.c, Revision 1.2

1.1       noro        1: /*
                      2:  * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
                      3:  * Copyright (c) 1997 by Silicon Graphics.  All rights reserved.
                      4:  * Copyright (c) 2000 by Hewlett-Packard Company.  All rights reserved.
                      5:  *
                      6:  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
                      7:  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
                      8:  *
                      9:  * Permission is hereby granted to use or copy this program
                     10:  * for any purpose,  provided the above notices are retained on all copies.
                     11:  * Permission to modify the code and to distribute modified code is granted,
                     12:  * provided the above notices are retained, and a notice that the code was
                     13:  * modified is included with the above copyright notice.
                     14:  *
                     15:  * Original author: Bill Janssen
                     16:  * Heavily modified by Hans Boehm and others
                     17:  */
                     18:
                     19: /*
                     20:  * This used to be in dyn_load.c.  It was extracted into a separate file
                     21:  * to avoid having to link against libdl.{a,so} if the client doesn't call
1.2     ! noro       22:  * dlopen.  Of course this fails if the collector is in a dynamic
        !            23:  * library. -HB
1.1       noro       24:  */
                     25:
                     26: #include "private/gc_priv.h"
                     27:
1.2     ! noro       28: # if (defined(GC_PTHREADS) && !defined(GC_DARWIN_THREADS)) \
        !            29:       || defined(GC_SOLARIS_THREADS)
1.1       noro       30:
                     31: # if defined(dlopen) && !defined(GC_USE_LD_WRAP)
                     32:     /* To support various threads pkgs, gc.h interposes on dlopen by     */
                     33:     /* defining "dlopen" to be "GC_dlopen", which is implemented below.  */
                     34:     /* However, both GC_FirstDLOpenedLinkMap() and GC_dlopen() use the   */
                     35:     /* real system dlopen() in their implementation. We first remove     */
                     36:     /* gc.h's dlopen definition and restore it later, after GC_dlopen(). */
                     37: #   undef dlopen
                     38: # endif
                     39:
                     40:   /* Make sure we're not in the middle of a collection, and make       */
                     41:   /* sure we don't start any.  Returns previous value of GC_dont_gc.   */
                     42:   /* This is invoked prior to a dlopen call to avoid synchronization   */
                     43:   /* issues.  We can't just acquire the allocation lock, since startup         */
                     44:   /* code in dlopen may try to allocate.                               */
                     45:   /* This solution risks heap growth in the presence of many dlopen    */
                     46:   /* calls in either a multithreaded environment, or if the library    */
                     47:   /* initialization code allocates substantial amounts of GC'ed memory.        */
                     48:   /* But I don't know of a better solution.                            */
1.2     ! noro       49:   static void disable_gc_for_dlopen()
1.1       noro       50:   {
                     51:     LOCK();
                     52:     while (GC_incremental && GC_collection_in_progress()) {
                     53:        GC_collect_a_little_inner(1000);
                     54:     }
1.2     ! noro       55:     ++GC_dont_gc;
1.1       noro       56:     UNLOCK();
                     57:   }
                     58:
                     59:   /* Redefine dlopen to guarantee mutual exclusion with        */
                     60:   /* GC_register_dynamic_libraries.                    */
                     61:   /* Should probably happen for other operating        systems, too. */
                     62:
                     63: #include <dlfcn.h>
                     64:
                     65: #ifdef GC_USE_LD_WRAP
                     66:   void * __wrap_dlopen(const char *path, int mode)
                     67: #else
                     68:   void * GC_dlopen(path, mode)
                     69:   GC_CONST char * path;
                     70:   int mode;
                     71: #endif
                     72: {
                     73:     void * result;
                     74:
                     75: #   ifndef USE_PROC_FOR_LIBRARIES
1.2     ! noro       76:       disable_gc_for_dlopen();
1.1       noro       77: #   endif
                     78: #   ifdef GC_USE_LD_WRAP
                     79:       result = (void *)__real_dlopen(path, mode);
                     80: #   else
                     81:       result = dlopen(path, mode);
                     82: #   endif
                     83: #   ifndef USE_PROC_FOR_LIBRARIES
1.2     ! noro       84:       GC_enable(); /* undoes disable_gc_for_dlopen */
1.1       noro       85: #   endif
                     86:     return(result);
                     87: }
                     88: # endif  /* GC_PTHREADS || GC_SOLARIS_THREADS ... */
                     89:
                     90:
                     91: