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  1. /* Yet Another Try at encapsulating bfd object files in coff.
  2.    Copyright 1988, 1989, 1991, 2010 Free Software Foundation, Inc.
  3.    Written by Pace Willisson 12/9/88
  4.  
  5.    This file is obsolete.  It needs to be converted to just define a bunch
  6.    of stuff that BFD can use to do coff-encapsulated files.  --gnu@cygnus.com
  7.  
  8.    This program is free software; you can redistribute it and/or modify
  9.    it under the terms of the GNU General Public License as published by
  10.    the Free Software Foundation; either version 3 of the License, or
  11.    (at your option) any later version.
  12.  
  13.    This program is distributed in the hope that it will be useful,
  14.    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16.    GNU General Public License for more details.
  17.  
  18.    You should have received a copy of the GNU General Public License
  19.    along with this program; if not, write to the Free Software
  20.    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21.    MA 02110-1301, USA.  */
  22.  
  23. /*
  24.  * We only use the coff headers to tell the kernel
  25.  * how to exec the file.  Therefore, the only fields that need to
  26.  * be filled in are the scnptr and vaddr for the text and data
  27.  * sections, and the vaddr for the bss.  As far as coff is concerned,
  28.  * there is no symbol table, relocation, or line numbers.
  29.  *
  30.  * A normal bsd header (struct exec) is placed after the coff headers,
  31.  * and before the real text.  I defined a the new fields 'a_machtype'
  32.  * and a_flags.  If a_machtype is M_386, and a_flags & A_ENCAP is
  33.  * true, then the bsd header is preceeded by a coff header.  Macros
  34.  * like N_TXTOFF and N_TXTADDR use this field to find the bsd header.
  35.  *
  36.  * The only problem is to track down the bsd exec header.  The
  37.  * macros HEADER_OFFSET, etc do this.
  38.  */
  39.  
  40. #define N_FLAGS_COFF_ENCAPSULATE 0x20 /* coff header precedes bsd header */
  41.  
  42. /* Describe the COFF header used for encapsulation.  */
  43.  
  44. struct coffheader
  45. {
  46.   /* filehdr */
  47.   unsigned short f_magic;
  48.   unsigned short f_nscns;
  49.   long f_timdat;
  50.   long f_symptr;
  51.   long f_nsyms;
  52.   unsigned short f_opthdr;
  53.   unsigned short f_flags;
  54.   /* aouthdr */
  55.   short magic;
  56.   short vstamp;
  57.   long tsize;
  58.   long dsize;
  59.   long bsize;
  60.   long entry;
  61.   long text_start;
  62.   long data_start;
  63.   struct coffscn
  64.     {
  65.       char s_name[8];
  66.       long s_paddr;
  67.       long s_vaddr;
  68.       long s_size;
  69.       long s_scnptr;
  70.       long s_relptr;
  71.       long s_lnnoptr;
  72.       unsigned short s_nreloc;
  73.       unsigned short s_nlnno;
  74.       long s_flags;
  75.     } scns[3];
  76. };
  78. /* Describe some of the parameters of the encapsulation,
  79.    including how to find the encapsulated BSD header.  */
  80.  
  81. /* FIXME, this is dumb.  The same tools can't handle a.outs for different
  82.    architectures, just because COFF_MAGIC is different; so you need a
  83.    separate GNU nm for every architecture!!?  Unfortunately, it needs to
  84.    be this way, since the COFF_MAGIC value is determined by the kernel
  85.    we're trying to fool here.  */
  86.    
  87. #define COFF_MAGIC_I386 0514 /* I386MAGIC */
  88. #define COFF_MAGIC_M68K 0520 /* MC68MAGIC */
  89.  
  90. #ifdef COFF_MAGIC
  91. short __header_offset_temp;
  92. #define HEADER_OFFSET(f) \
  93.         (__header_offset_temp = 0, \
  94.          fread ((char *)&__header_offset_temp, sizeof (short), 1, (f)), \
  95.          fseek ((f), -sizeof (short), 1), \
  96.          __header_offset_temp==COFF_MAGIC ? sizeof(struct coffheader) : 0)
  97. #else
  98. #define HEADER_OFFSET(f) 0
  99. #endif
  100.  
  101. #define HEADER_SEEK(f) (fseek ((f), HEADER_OFFSET((f)), 1))
  103. /* Describe the characteristics of the BSD header
  104.    that appears inside the encapsulation.  */
  105.  
  106. /* Encapsulated coff files that are linked ZMAGIC have a text segment
  107.    offset just past the header (and a matching TXTADDR), excluding
  108.    the headers from the text segment proper but keeping the physical
  109.    layout and the virtual memory layout page-aligned.
  110.  
  111.    Non-encapsulated a.out files that are linked ZMAGIC have a text
  112.    segment that starts at 0 and an N_TXTADR similarly offset to 0.
  113.    They too are page-aligned with each other, but they include the
  114.    a.out header as part of the text.
  115.  
  116.    The _N_HDROFF gets sizeof struct exec added to it, so we have
  117.    to compensate here.  See <a.out.gnu.h>.  */
  118.  
  119. #undef _N_HDROFF
  120. #undef N_TXTADDR
  121. #undef N_DATADDR
  122.  
  123. #define _N_HDROFF(x) ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
  124.                       sizeof (struct coffheader) : 0)
  125.  
  126. /* Address of text segment in memory after it is loaded.  */
  127. #define N_TXTADDR(x) \
  128.         ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
  129.          sizeof (struct coffheader) + sizeof (struct exec) : 0)
  130. #define SEGMENT_SIZE 0x400000
  131.  
  132. #define N_DATADDR(x) \
  133.         ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
  134.          (SEGMENT_SIZE + ((N_TXTADDR(x)+(x).a_text-1) & ~(SEGMENT_SIZE-1))) : \
  135.          (N_TXTADDR(x)+(x).a_text))
  136.