libmacho/get_end.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 #ifndef RLD
  24 #include <string.h>
  25 #include <mach-o/ldsyms.h>
  26 #include <mach-o/getsect.h>
  27 #ifndef __OPENSTEP__
  28
  29 #ifdef __LP64__
  30 extern struct mach_header_64 *_NSGetMachExecuteHeader(void);
  31 #else /* !defined(__LP64__) */
  32 #include <crt_externs.h>
  33 #endif /* !defined(__LP64__) */
  34
  35 #else /* defined(__OPENSTEP__) */
  36 #ifdef __DYNAMIC__
  37 #include "mach-o/dyld.h" /* defines _dyld_lookup_and_bind() */
  38 #endif
  39
  40 #if !defined(__DYNAMIC__)
  41 #define DECLARE_VAR(var, type) \
  42 extern type var
  43 #define SETUP_VAR(var)
  44 #define USE_VAR(var) var
  45 #else
  46 #define STRINGIFY(a) # a
  47 #define DECLARE_VAR(var, type)  \
  48 static type * var ## _pointer = 0
  49 #define SETUP_VAR(var)                                          \
  50 if ( var ## _pointer == 0) {                            \
  51     _dyld_lookup_and_bind( STRINGIFY(_ ## var),         \
  52                            (unsigned long *) & var ## _pointer, 0);     \
  53 }
  54 #define USE_VAR(var) (* var ## _pointer)
  55 #endif
  56 #endif /* __OPENSTEP__ */
  57
  58 /*
  59  * This routine returns the highest address of the segments in the program (NOT
  60  * the shared libraries).  It is intended to be used as a stop gap for programs
  61  * that make UNIX style assumptions about how memory is allocated.  Typicly the
  62  * asumptions under which this is used is that memory is contiguously allocated
  63  * by the program's text and data from address 0 with no gaps.  The value of
  64  * this differs from the value of &_end in a UNIX program in that this routine
  65  * returns the address of the end of the segment not the end of the last section
  66  * in that segment as would be the value of the symbol &_end.
  67  */
  68 unsigned long
  69 get_end(void)
  70 {
  71 #ifndef __LP64__
  72
  73     static struct mach_header *mhp = NULL;
  74     struct segment_command *sgp;
  75     unsigned long i, _end;
  76 #ifndef __OPENSTEP__
  77         if(mhp == NULL)
  78             mhp = _NSGetMachExecuteHeader();
  79 #else /* defined(__OPENSTEP__) */
  80         DECLARE_VAR(_mh_execute_header, struct mach_header);
  81         SETUP_VAR(_mh_execute_header);
  82
  83         mhp = (struct mach_header *)(& USE_VAR(_mh_execute_header));
  84 #endif /* __OPENSTEP__ */
  85         _end = 0;
  86         sgp = (struct segment_command *)
  87               ((char *)mhp + sizeof(struct mach_header));
  88         for(i = 0; i < mhp->ncmds; i++){
  89             if(sgp->cmd == LC_SEGMENT)
  90                 if(sgp->vmaddr + sgp->vmsize > _end)
  91                     _end = sgp->vmaddr + sgp->vmsize;
  92             sgp = (struct segment_command *)((char *)sgp + sgp->cmdsize);
  93         }
  94         return(_end);
  95
  96 #else /* defined(__LP64__) */
  97
  98     static struct mach_header_64 *mhp = NULL;
  99     struct segment_command_64 *sgp;
 100     unsigned long i, _end;
 101
 102         if(mhp == NULL)
 103             mhp = _NSGetMachExecuteHeader();
 104         _end = 0;
 105         sgp = (struct segment_command_64 *)
 106               ((char *)mhp + sizeof(struct mach_header_64));
 107         for(i = 0; i < mhp->ncmds; i++){
 108             if(sgp->cmd == LC_SEGMENT_64)
 109                 if(sgp->vmaddr + sgp->vmsize > _end)
 110                     _end = sgp->vmaddr + sgp->vmsize;
 111             sgp = (struct segment_command_64 *)((char *)sgp + sgp->cmdsize);
 112         }
 113         return(_end);
 114
 115 #endif /* defined(__LP64__) */
 116 }
 117
 118 /*
 119  * This returns what was the value of the UNIX link editor defined symbol
 120  * _etext (the first address after the text section).  Note this my or may not
 121  * be the only section in the __TEXT segment.
 122  */
 123 unsigned long
 124 get_etext(void)
 125 {
 126 #ifndef __LP64__
 127     const struct section *sp;
 128 #else /* defined(__LP64__) */
 129     const struct section_64 *sp;
 130 #endif /* defined(__LP64__) */
 131
 132         sp = getsectbyname(SEG_TEXT, SECT_TEXT);
 133         if(sp)
 134             return(sp->addr + sp->size);
 135         else
 136             return(0);
 137 }
 138
 139 /*
 140  * This returns what was the value of the UNIX link editor defined symbol
 141  * _edata (the first address after the data section).  Note this my or may not
 142  * be the last non-zero fill section in the __DATA segment.
 143  */
 144 unsigned long
 145 get_edata(void)
 146 {
 147 #ifndef __LP64__
 148     const struct section *sp;
 149 #else /* defined(__LP64__) */
 150     const struct section_64 *sp;
 151 #endif /* defined(__LP64__) */
 152
 153         sp = getsectbyname(SEG_DATA, SECT_DATA);
 154         if(sp)
 155             return(sp->addr + sp->size);
 156         else
 157             return(0);
 158 }
 159 #endif /* !defined(RLD) */