libstuff/get_toc_byte_sex.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 #include <stdlib.h>
  24 #include <string.h>
  25 #include <ar.h>
  26 #ifndef AR_EFMT1
  27 #define AR_EFMT1        "#1/"           /* extended format #1 */
  28 #endif
  29 #include <mach-o/loader.h>
  30 #include <stuff/bytesex.h>
  31 #include <stuff/round.h>
  32
  33 /*
  34  * get_toc_byte_sex() guesses the byte sex of the table of contents of the
  35  * library mapped in at the address, addr, of size, size based on the first
  36  * object file's bytesex.  If it can't figure it out, because the library has
  37  * no object file members or is malformed it will return UNKNOWN_BYTE_SEX.
  38  */
  39 __private_extern__
  40 enum byte_sex
  41 get_toc_byte_sex(
  42 char *addr,
  43 unsigned long size)
  44 {
  45      uint32_t magic;
  46      unsigned long ar_name_size;
  47      struct ar_hdr *ar_hdr;
  48      char *p;
  49
  50         ar_hdr = (struct ar_hdr *)(addr + SARMAG);
  51
  52         p = addr + SARMAG + sizeof(struct ar_hdr) +
  53             round(strtoul(ar_hdr->ar_size, NULL, 10), sizeof(short));
  54         while(p + sizeof(struct ar_hdr) + sizeof(uint32_t) < addr + size){
  55             ar_hdr = (struct ar_hdr *)p;
  56             if(strncmp(ar_hdr->ar_name, AR_EFMT1, sizeof(AR_EFMT1) - 1) == 0)
  57                 ar_name_size = strtoul(ar_hdr->ar_name + sizeof(AR_EFMT1) - 1,
  58                                        NULL, 10);
  59             else
  60                 ar_name_size = 0;
  61             p += sizeof(struct ar_hdr);
  62             memcpy(&magic, p + ar_name_size, sizeof(uint32_t));
  63             if(magic == MH_MAGIC || magic == MH_MAGIC_64)
  64                 return(get_host_byte_sex());
  65             else if(magic == SWAP_INT(MH_MAGIC) ||
  66                     magic == SWAP_INT(MH_MAGIC_64))
  67                 return(get_host_byte_sex() == BIG_ENDIAN_BYTE_SEX ?
  68                        LITTLE_ENDIAN_BYTE_SEX : BIG_ENDIAN_BYTE_SEX);
  69             p += round(strtoul(ar_hdr->ar_size, NULL, 10), sizeof(short));
  70         }
  71         return(UNKNOWN_BYTE_SEX);
  72 }