sys/crt_externs.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26 ** This file contains interfaces to the symbols defined int the crt modules.
  27 ** 3 April 1995
  28 ** Matt Watson (mwatson@next.com)
  29 **
  30 */
  31
  32 #if defined(__DYNAMIC__)
  33 #include "mach-o/dyld.h" /* defines _dyld_lookup_and_bind() */
  34 #define STRINGIFY(a) # a
  35 #define DECLARE_VAR(var, type)  \
  36         static type * var ## _pointer = 0
  37 #define SETUP_VAR(var)                                          \
  38     if ( var ## _pointer == 0) {                                \
  39         _dyld_lookup_and_bind( STRINGIFY(_ ## var),             \
  40                 (unsigned long *) & var ## _pointer, 0);        \
  41     }
  42 #define USE_VAR(var) (var ## _pointer)
  43 #else
  44 #define DECLARE_VAR(var, type) extern type var
  45 #define SETUP_VAR(var)
  46 #define USE_VAR(var) (& var)
  47 #endif
  48
  49 char ***_NSGetArgv(void) {
  50     DECLARE_VAR(NXArgv, char **);
  51     SETUP_VAR(NXArgv);
  52     return(USE_VAR(NXArgv));
  53 }
  54
  55 int *_NSGetArgc(void) {
  56     DECLARE_VAR(NXArgc, int);
  57     SETUP_VAR(NXArgc);
  58     return(USE_VAR(NXArgc));
  59 }
  60
  61 char ***_NSGetEnviron(void) {
  62     DECLARE_VAR(environ, char **);
  63     SETUP_VAR(environ);
  64     return(USE_VAR(environ));
  65 }
  66
  67 char **_NSGetProgname(void) {
  68     DECLARE_VAR(__progname, char *);
  69     SETUP_VAR(__progname);
  70     return(USE_VAR(__progname));
  71 }
  72
  73 struct mach_header *_NSGetMachExecuteHeader(void) {
  74     DECLARE_VAR(_mh_execute_header, struct mach_header);
  75     SETUP_VAR(_mh_execute_header);
  76     return(USE_VAR(_mh_execute_header));
  77 }
  78
  79 /*
  80  * Fix for Radar bug 2200596 --
  81  * EH symbol definitions for gcc 2.7.2.x implementation of
  82  * C++ exception handling.  The problem:  the EH implementation
  83  * has "throw" store stuff into these pointers, and then as the
  84  * stack is unwound, the code generated into each function (for
  85  * checking whether this function contains a relevant "catch"
  86  * clause and for calling destructors for local variables) looks
  87  * at these globals to find the type and value thrown.
  88  *
  89  * The problem was that the compiler generated the symbols as
  90  * "common" symbols, and common symbols cannot be placed in
  91  * dynamic shared libraries.  So we must put these guys as
  92  * "data" symbols into crt0.o or the System Framework (library),
  93  * and the compiler must generate code that defines the symbols
  94  * as external references instead of common.
  95  *
  96  * I changed the symbol names (added the "_272") to be utterly
  97  * paranoid about any possible future use of similar names by
  98  * any future versions of gcc.
  99  *                      -- D. Landauer, Jan. 1998
 100  */
 101
 102 void *__eh_pc_gcc_272 = (void *)0;
 103 void *__eh_type_gcc_272 = (void *)0;
 104 void *__eh_value_gcc_272 = (void *)0;
 105
 106 /* This is what egcs uses for its global data pointer */
 107 void *__eh_global_dataptr = (void *)0;
 108
 109 void *__keymgr_global[3] = { (void *)0 };