bfd/i386msdos.c

   1 /* BFD back-end for MS-DOS executables.
   2    Copyright 1990, 91, 92, 93, 94, 95, 96, 1997 Free Software Foundation, Inc.
   3    Written by Bryan Ford of the University of Utah.
   4
   5    Contributed by the Center for Software Science at the
   6    University of Utah (pa-gdb-bugs@cs.utah.edu).
   7
   8    This file is part of BFD, the Binary File Descriptor library.
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 2 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program; if not, write to the Free Software
  22    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  23
  24
  25 #include "bfd.h"
  26 #include "sysdep.h"
  27 #include "libbfd.h"
  28 #include "libaout.h"
  29
  30 #if 0
  31 struct exe_header
  32 {
  33         unsigned short magic;
  34         unsigned short bytes_in_last_page;
  35         unsigned short npages;  /* number of 512-byte "pages" including this header */
  36         unsigned short nrelocs;
  37         unsigned short header_paras;    /* number of 16-byte paragraphs in header */
  38         unsigned short reserved;
  39         unsigned short load_switch;
  40         unsigned short ss_ofs;
  41         unsigned short sp;
  42         unsigned short checksum;
  43         unsigned short ip;
  44         unsigned short cs_ofs;
  45         unsigned short reloc_ofs;
  46         unsigned short reserved2;
  47         unsigned short something1;
  48         unsigned short something2;
  49         unsigned short something3;
  50 };
  51 #endif
  52
  53 #define EXE_MAGIC       0x5a4d
  54 #define EXE_LOAD_HIGH   0x0000
  55 #define EXE_LOAD_LOW    0xffff
  56 #define EXE_PAGE_SIZE   512
  57
  58
  59 static int
  60 msdos_sizeof_headers (abfd, exec)
  61      bfd *abfd;
  62      boolean exec;
  63 {
  64   return 0;
  65 }
  66
  67 static boolean
  68 msdos_write_object_contents (abfd)
  69      bfd *abfd;
  70 {
  71   static char hdr[EXE_PAGE_SIZE];
  72   file_ptr outfile_size = sizeof(hdr);
  73   bfd_vma high_vma = 0;
  74   asection *sec;
  75
  76   /* Find the total size of the program on disk and in memory.  */
  77   for (sec = abfd->sections; sec != (asection *) NULL; sec = sec->next)
  78     {
  79       if (bfd_get_section_size_before_reloc (sec) == 0)
  80         continue;
  81       if (bfd_get_section_flags (abfd, sec) & SEC_ALLOC)
  82         {
  83           bfd_vma sec_vma = bfd_get_section_vma (abfd, sec)
  84                             + bfd_get_section_size_before_reloc (sec);
  85           if (sec_vma > high_vma)
  86             high_vma = sec_vma;
  87         }
  88       if (bfd_get_section_flags (abfd, sec) & SEC_LOAD)
  89         {
  90           file_ptr sec_end = sizeof(hdr)
  91                              + bfd_get_section_vma (abfd, sec)
  92                              + bfd_get_section_size_before_reloc (sec);
  93           if (sec_end > outfile_size)
  94             outfile_size = sec_end;
  95         }
  96     }
  97
  98   /* Make sure the program isn't too big.  */
  99   if (high_vma > (bfd_vma)0xffff)
 100     {
 101       bfd_set_error(bfd_error_file_too_big);
 102       return false;
 103     }
 104
 105   /* constants */
 106   bfd_h_put_16(abfd, EXE_MAGIC, &hdr[0]);
 107   bfd_h_put_16(abfd, EXE_PAGE_SIZE / 16, &hdr[8]);
 108   bfd_h_put_16(abfd, EXE_LOAD_LOW, &hdr[12]);
 109   bfd_h_put_16(abfd, 0x3e, &hdr[24]);
 110   bfd_h_put_16(abfd, 0x0001, &hdr[28]); /* XXX??? */
 111   bfd_h_put_16(abfd, 0x30fb, &hdr[30]); /* XXX??? */
 112   bfd_h_put_16(abfd, 0x726a, &hdr[32]); /* XXX??? */
 113
 114   /* bytes in last page (0 = full page) */
 115   bfd_h_put_16(abfd, outfile_size & (EXE_PAGE_SIZE - 1), &hdr[2]);
 116
 117   /* number of pages */
 118   bfd_h_put_16(abfd, (outfile_size + EXE_PAGE_SIZE - 1) / EXE_PAGE_SIZE,
 119                &hdr[4]);
 120
 121   /* Set the initial stack pointer to the end of the bss.
 122      The program's crt0 code must relocate it to a real stack.  */
 123   bfd_h_put_16(abfd, high_vma, &hdr[16]);
 124
 125   if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0
 126       || bfd_write (hdr, 1, sizeof(hdr), abfd) != sizeof(hdr))
 127     return false;
 128
 129   return true;
 130 }
 131
 132 static boolean
 133 msdos_set_section_contents (abfd, section, location, offset, count)
 134      bfd *abfd;
 135      sec_ptr section;
 136      PTR location;
 137      file_ptr offset;
 138      bfd_size_type count;
 139 {
 140
 141   if (count == 0)
 142     return true;
 143
 144   section->filepos = EXE_PAGE_SIZE + bfd_get_section_vma (abfd, section);
 145
 146   if (bfd_get_section_flags (abfd, section) & SEC_LOAD)
 147     {
 148       if (bfd_seek (abfd, (file_ptr) (section->filepos + offset), SEEK_SET) != 0
 149           || bfd_write (location, 1, count, abfd) != count)
 150         return false;
 151     }
 152
 153   return true;
 154 }
 155
 156
 157
 158 #define msdos_mkobject aout_32_mkobject
 159 #define msdos_make_empty_symbol aout_32_make_empty_symbol
 160 #define msdos_bfd_reloc_type_lookup aout_32_reloc_type_lookup
 161
 162 #define msdos_close_and_cleanup _bfd_generic_close_and_cleanup
 163 #define msdos_bfd_free_cached_info _bfd_generic_bfd_free_cached_info
 164 #define msdos_new_section_hook _bfd_generic_new_section_hook
 165 #define msdos_get_section_contents _bfd_generic_get_section_contents
 166 #define msdos_get_section_contents_in_window \
 167   _bfd_generic_get_section_contents_in_window
 168 #define msdos_bfd_get_relocated_section_contents \
 169   bfd_generic_get_relocated_section_contents
 170 #define msdos_bfd_relax_section bfd_generic_relax_section
 171 #define msdos_bfd_gc_sections bfd_generic_gc_sections
 172 #define msdos_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
 173 #define msdos_bfd_link_add_symbols _bfd_generic_link_add_symbols
 174 #define msdos_bfd_final_link _bfd_generic_final_link
 175 #define msdos_bfd_link_split_section _bfd_generic_link_split_section
 176 #define msdos_set_arch_mach _bfd_generic_set_arch_mach
 177
 178 #define msdos_get_symtab_upper_bound _bfd_nosymbols_get_symtab_upper_bound
 179 #define msdos_get_symtab _bfd_nosymbols_get_symtab
 180 #define msdos_print_symbol _bfd_nosymbols_print_symbol
 181 #define msdos_get_symbol_info _bfd_nosymbols_get_symbol_info
 182 #define msdos_find_nearest_line _bfd_nosymbols_find_nearest_line
 183 #define msdos_get_lineno _bfd_nosymbols_get_lineno
 184 #define msdos_bfd_is_local_label_name _bfd_nosymbols_bfd_is_local_label_name
 185 #define msdos_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
 186 #define msdos_read_minisymbols _bfd_nosymbols_read_minisymbols
 187 #define msdos_minisymbol_to_symbol _bfd_nosymbols_minisymbol_to_symbol
 188
 189 #define msdos_canonicalize_reloc _bfd_norelocs_canonicalize_reloc
 190 #define msdos_get_reloc_upper_bound _bfd_norelocs_get_reloc_upper_bound
 191 #define msdos_32_bfd_link_split_section  _bfd_generic_link_split_section
 192
 193 const bfd_target i386msdos_vec =
 194 {
 195   "msdos",                      /* name */
 196   bfd_target_msdos_flavour,
 197   BFD_ENDIAN_LITTLE,            /* target byte order */
 198   BFD_ENDIAN_LITTLE,            /* target headers byte order */
 199   (EXEC_P),                     /* object flags */
 200   (SEC_CODE | SEC_DATA | SEC_HAS_CONTENTS
 201    | SEC_ALLOC | SEC_LOAD),     /* section flags */
 202   0,                            /* leading underscore */
 203   ' ',                          /* ar_pad_char */
 204   16,                           /* ar_max_namelen */
 205   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 206   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 207   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* data */
 208   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 209   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 210   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* hdrs */
 211
 212   {
 213     _bfd_dummy_target,
 214     _bfd_dummy_target,          /* bfd_check_format */
 215     _bfd_dummy_target,
 216     _bfd_dummy_target,
 217   },
 218   {
 219     bfd_false,
 220     msdos_mkobject,
 221     _bfd_generic_mkarchive,
 222     bfd_false,
 223   },
 224   {                             /* bfd_write_contents */
 225     bfd_false,
 226     msdos_write_object_contents,
 227     _bfd_write_archive_contents,
 228     bfd_false,
 229   },
 230
 231   BFD_JUMP_TABLE_GENERIC (msdos),
 232   BFD_JUMP_TABLE_COPY (_bfd_generic),
 233   BFD_JUMP_TABLE_CORE (_bfd_nocore),
 234   BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 235   BFD_JUMP_TABLE_SYMBOLS (msdos),
 236   BFD_JUMP_TABLE_RELOCS (msdos),
 237   BFD_JUMP_TABLE_WRITE (msdos),
 238   BFD_JUMP_TABLE_LINK (msdos),
 239   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 240
 241   (PTR) 0
 242 };
 243
 244