bfd/i386msdos.c

   1 /* BFD back-end for MS-DOS executables.
   2    Copyright 1990, 91, 92, 93, 94, 95, 96, 97, 98, 1999
   3    Free Software Foundation, Inc.
   4    Written by Bryan Ford of the University of Utah.
   5
   6    Contributed by the Center for Software Science at the
   7    University of Utah (pa-gdb-bugs@cs.utah.edu).
   8
   9    This file is part of BFD, the Binary File Descriptor library.
  10
  11    This program is free software; you can redistribute it and/or modify
  12    it under the terms of the GNU General Public License as published by
  13    the Free Software Foundation; either version 2 of the License, or
  14    (at your option) any later version.
  15
  16    This program is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21    You should have received a copy of the GNU General Public License
  22    along with this program; if not, write to the Free Software
  23    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  24
  25
  26 #include "bfd.h"
  27 #include "sysdep.h"
  28 #include "libbfd.h"
  29 #include "libaout.h"
  30
  31 #if 0
  32 struct exe_header
  33 {
  34         unsigned short magic;
  35         unsigned short bytes_in_last_page;
  36         unsigned short npages;  /* number of 512-byte "pages" including this header */
  37         unsigned short nrelocs;
  38         unsigned short header_paras;    /* number of 16-byte paragraphs in header */
  39         unsigned short reserved;
  40         unsigned short load_switch;
  41         unsigned short ss_ofs;
  42         unsigned short sp;
  43         unsigned short checksum;
  44         unsigned short ip;
  45         unsigned short cs_ofs;
  46         unsigned short reloc_ofs;
  47         unsigned short reserved2;
  48         unsigned short something1;
  49         unsigned short something2;
  50         unsigned short something3;
  51 };
  52 #endif
  53
  54 #define EXE_MAGIC       0x5a4d
  55 #define EXE_LOAD_HIGH   0x0000
  56 #define EXE_LOAD_LOW    0xffff
  57 #define EXE_PAGE_SIZE   512
  58
  59
  60 static int
  61 msdos_sizeof_headers (abfd, exec)
  62      bfd *abfd ATTRIBUTE_UNUSED;
  63      boolean exec ATTRIBUTE_UNUSED;
  64 {
  65   return 0;
  66 }
  67
  68 static boolean
  69 msdos_write_object_contents (abfd)
  70      bfd *abfd;
  71 {
  72   static char hdr[EXE_PAGE_SIZE];
  73   file_ptr outfile_size = sizeof(hdr);
  74   bfd_vma high_vma = 0;
  75   asection *sec;
  76
  77   /* Find the total size of the program on disk and in memory.  */
  78   for (sec = abfd->sections; sec != (asection *) NULL; sec = sec->next)
  79     {
  80       if (bfd_get_section_size_before_reloc (sec) == 0)
  81         continue;
  82       if (bfd_get_section_flags (abfd, sec) & SEC_ALLOC)
  83         {
  84           bfd_vma sec_vma = bfd_get_section_vma (abfd, sec)
  85                             + bfd_get_section_size_before_reloc (sec);
  86           if (sec_vma > high_vma)
  87             high_vma = sec_vma;
  88         }
  89       if (bfd_get_section_flags (abfd, sec) & SEC_LOAD)
  90         {
  91           file_ptr sec_end = sizeof(hdr)
  92                              + bfd_get_section_vma (abfd, sec)
  93                              + bfd_get_section_size_before_reloc (sec);
  94           if (sec_end > outfile_size)
  95             outfile_size = sec_end;
  96         }
  97     }
  98
  99   /* Make sure the program isn't too big.  */
 100   if (high_vma > (bfd_vma)0xffff)
 101     {
 102       bfd_set_error(bfd_error_file_too_big);
 103       return false;
 104     }
 105
 106   /* constants */
 107   bfd_h_put_16(abfd, EXE_MAGIC, &hdr[0]);
 108   bfd_h_put_16(abfd, EXE_PAGE_SIZE / 16, &hdr[8]);
 109   bfd_h_put_16(abfd, EXE_LOAD_LOW, &hdr[12]);
 110   bfd_h_put_16(abfd, 0x3e, &hdr[24]);
 111   bfd_h_put_16(abfd, 0x0001, &hdr[28]); /* XXX??? */
 112   bfd_h_put_16(abfd, 0x30fb, &hdr[30]); /* XXX??? */
 113   bfd_h_put_16(abfd, 0x726a, &hdr[32]); /* XXX??? */
 114
 115   /* bytes in last page (0 = full page) */
 116   bfd_h_put_16(abfd, outfile_size & (EXE_PAGE_SIZE - 1), &hdr[2]);
 117
 118   /* number of pages */
 119   bfd_h_put_16(abfd, (outfile_size + EXE_PAGE_SIZE - 1) / EXE_PAGE_SIZE,
 120                &hdr[4]);
 121
 122   /* Set the initial stack pointer to the end of the bss.
 123      The program's crt0 code must relocate it to a real stack.  */
 124   bfd_h_put_16(abfd, high_vma, &hdr[16]);
 125
 126   if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0
 127       || bfd_write (hdr, 1, sizeof(hdr), abfd) != sizeof(hdr))
 128     return false;
 129
 130   return true;
 131 }
 132
 133 static boolean
 134 msdos_set_section_contents (abfd, section, location, offset, count)
 135      bfd *abfd;
 136      sec_ptr section;
 137      PTR location;
 138      file_ptr offset;
 139      bfd_size_type count;
 140 {
 141
 142   if (count == 0)
 143     return true;
 144
 145   section->filepos = EXE_PAGE_SIZE + bfd_get_section_vma (abfd, section);
 146
 147   if (bfd_get_section_flags (abfd, section) & SEC_LOAD)
 148     {
 149       if (bfd_seek (abfd, (file_ptr) (section->filepos + offset), SEEK_SET) != 0
 150           || bfd_write (location, 1, count, abfd) != count)
 151         return false;
 152     }
 153
 154   return true;
 155 }
 156
 157
 158
 159 #define msdos_mkobject aout_32_mkobject
 160 #define msdos_make_empty_symbol aout_32_make_empty_symbol
 161 #define msdos_bfd_reloc_type_lookup aout_32_reloc_type_lookup
 162
 163 #define msdos_close_and_cleanup _bfd_generic_close_and_cleanup
 164 #define msdos_bfd_free_cached_info _bfd_generic_bfd_free_cached_info
 165 #define msdos_new_section_hook _bfd_generic_new_section_hook
 166 #define msdos_get_section_contents _bfd_generic_get_section_contents
 167 #define msdos_get_section_contents_in_window \
 168   _bfd_generic_get_section_contents_in_window
 169 #define msdos_bfd_get_relocated_section_contents \
 170   bfd_generic_get_relocated_section_contents
 171 #define msdos_bfd_relax_section bfd_generic_relax_section
 172 #define msdos_bfd_gc_sections bfd_generic_gc_sections
 173 #define msdos_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
 174 #define msdos_bfd_link_add_symbols _bfd_generic_link_add_symbols
 175 #define msdos_bfd_final_link _bfd_generic_final_link
 176 #define msdos_bfd_link_split_section _bfd_generic_link_split_section
 177 #define msdos_set_arch_mach _bfd_generic_set_arch_mach
 178
 179 #define msdos_get_symtab_upper_bound _bfd_nosymbols_get_symtab_upper_bound
 180 #define msdos_get_symtab _bfd_nosymbols_get_symtab
 181 #define msdos_print_symbol _bfd_nosymbols_print_symbol
 182 #define msdos_get_symbol_info _bfd_nosymbols_get_symbol_info
 183 #define msdos_find_nearest_line _bfd_nosymbols_find_nearest_line
 184 #define msdos_get_lineno _bfd_nosymbols_get_lineno
 185 #define msdos_bfd_is_local_label_name _bfd_nosymbols_bfd_is_local_label_name
 186 #define msdos_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
 187 #define msdos_read_minisymbols _bfd_nosymbols_read_minisymbols
 188 #define msdos_minisymbol_to_symbol _bfd_nosymbols_minisymbol_to_symbol
 189
 190 #define msdos_canonicalize_reloc _bfd_norelocs_canonicalize_reloc
 191 #define msdos_get_reloc_upper_bound _bfd_norelocs_get_reloc_upper_bound
 192 #define msdos_32_bfd_link_split_section  _bfd_generic_link_split_section
 193
 194 const bfd_target i386msdos_vec =
 195 {
 196   "msdos",                      /* name */
 197   bfd_target_msdos_flavour,
 198   BFD_ENDIAN_LITTLE,            /* target byte order */
 199   BFD_ENDIAN_LITTLE,            /* target headers byte order */
 200   (EXEC_P),                     /* object flags */
 201   (SEC_CODE | SEC_DATA | SEC_HAS_CONTENTS
 202    | SEC_ALLOC | SEC_LOAD),     /* section flags */
 203   0,                            /* leading underscore */
 204   ' ',                          /* ar_pad_char */
 205   16,                           /* ar_max_namelen */
 206   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 207   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 208   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* data */
 209   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 210   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 211   bfd_getl16, bfd_getl_signed_16, bfd_putl16,   /* hdrs */
 212
 213   {
 214     _bfd_dummy_target,
 215     _bfd_dummy_target,          /* bfd_check_format */
 216     _bfd_dummy_target,
 217     _bfd_dummy_target,
 218   },
 219   {
 220     bfd_false,
 221     msdos_mkobject,
 222     _bfd_generic_mkarchive,
 223     bfd_false,
 224   },
 225   {                             /* bfd_write_contents */
 226     bfd_false,
 227     msdos_write_object_contents,
 228     _bfd_write_archive_contents,
 229     bfd_false,
 230   },
 231
 232   BFD_JUMP_TABLE_GENERIC (msdos),
 233   BFD_JUMP_TABLE_COPY (_bfd_generic),
 234   BFD_JUMP_TABLE_CORE (_bfd_nocore),
 235   BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 236   BFD_JUMP_TABLE_SYMBOLS (msdos),
 237   BFD_JUMP_TABLE_RELOCS (msdos),
 238   BFD_JUMP_TABLE_WRITE (msdos),
 239   BFD_JUMP_TABLE_LINK (msdos),
 240   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 241
 242   NULL,
 243
 244   (PTR) 0
 245 };
 246
 247