bfd/i386msdos.c

   1 /* BFD back-end for MS-DOS executables.
   2    Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2001, 2002,
   3    2003, 2004, 2005 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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
  24
  25
  26 #include "bfd.h"
  27 #include "sysdep.h"
  28 #include "libbfd.h"
  29 #include "libaout.h"
  30
  31 #define EXE_MAGIC       0x5a4d
  32 #define EXE_LOAD_HIGH   0x0000
  33 #define EXE_LOAD_LOW    0xffff
  34 #define EXE_PAGE_SIZE   512
  35
  36 static int msdos_sizeof_headers
  37   PARAMS ((bfd *, bfd_boolean));
  38 static bfd_boolean msdos_write_object_contents
  39   PARAMS ((bfd *));
  40 static bfd_boolean msdos_set_section_contents
  41   PARAMS ((bfd *, sec_ptr, const PTR, file_ptr, bfd_size_type));
  42
  43 static int
  44 msdos_sizeof_headers (abfd, exec)
  45      bfd *abfd ATTRIBUTE_UNUSED;
  46      bfd_boolean exec ATTRIBUTE_UNUSED;
  47 {
  48   return 0;
  49 }
  50
  51 static bfd_boolean
  52 msdos_write_object_contents (abfd)
  53      bfd *abfd;
  54 {
  55   static char hdr[EXE_PAGE_SIZE];
  56   file_ptr outfile_size = sizeof(hdr);
  57   bfd_vma high_vma = 0;
  58   asection *sec;
  59
  60   /* Find the total size of the program on disk and in memory.  */
  61   for (sec = abfd->sections; sec != (asection *) NULL; sec = sec->next)
  62     {
  63       if (sec->size == 0)
  64         continue;
  65       if (bfd_get_section_flags (abfd, sec) & SEC_ALLOC)
  66         {
  67           bfd_vma sec_vma = bfd_get_section_vma (abfd, sec) + sec->size;
  68           if (sec_vma > high_vma)
  69             high_vma = sec_vma;
  70         }
  71       if (bfd_get_section_flags (abfd, sec) & SEC_LOAD)
  72         {
  73           file_ptr sec_end = (sizeof (hdr)
  74                               + bfd_get_section_vma (abfd, sec)
  75                               + sec->size);
  76           if (sec_end > outfile_size)
  77             outfile_size = sec_end;
  78         }
  79     }
  80
  81   /* Make sure the program isn't too big.  */
  82   if (high_vma > (bfd_vma)0xffff)
  83     {
  84       bfd_set_error(bfd_error_file_too_big);
  85       return FALSE;
  86     }
  87
  88   /* Constants.  */
  89   H_PUT_16 (abfd, EXE_MAGIC, &hdr[0]);
  90   H_PUT_16 (abfd, EXE_PAGE_SIZE / 16, &hdr[8]);
  91   H_PUT_16 (abfd, EXE_LOAD_LOW, &hdr[12]);
  92   H_PUT_16 (abfd, 0x3e, &hdr[24]);
  93   H_PUT_16 (abfd, 0x0001, &hdr[28]); /* XXX??? */
  94   H_PUT_16 (abfd, 0x30fb, &hdr[30]); /* XXX??? */
  95   H_PUT_16 (abfd, 0x726a, &hdr[32]); /* XXX??? */
  96
  97   /* Bytes in last page (0 = full page).  */
  98   H_PUT_16 (abfd, outfile_size & (EXE_PAGE_SIZE - 1), &hdr[2]);
  99
 100   /* Number of pages.  */
 101   H_PUT_16 (abfd, (outfile_size + EXE_PAGE_SIZE - 1) / EXE_PAGE_SIZE, &hdr[4]);
 102
 103   /* Set the initial stack pointer to the end of the bss.
 104      The program's crt0 code must relocate it to a real stack.  */
 105   H_PUT_16 (abfd, high_vma, &hdr[16]);
 106
 107   if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0
 108       || bfd_bwrite (hdr, (bfd_size_type) sizeof(hdr), abfd) != sizeof(hdr))
 109     return FALSE;
 110
 111   return TRUE;
 112 }
 113
 114 static bfd_boolean
 115 msdos_set_section_contents (abfd, section, location, offset, count)
 116      bfd *abfd;
 117      sec_ptr section;
 118      const PTR location;
 119      file_ptr offset;
 120      bfd_size_type count;
 121 {
 122
 123   if (count == 0)
 124     return TRUE;
 125
 126   section->filepos = EXE_PAGE_SIZE + bfd_get_section_vma (abfd, section);
 127
 128   if (bfd_get_section_flags (abfd, section) & SEC_LOAD)
 129     {
 130       if (bfd_seek (abfd, section->filepos + offset, SEEK_SET) != 0
 131           || bfd_bwrite (location, count, abfd) != count)
 132         return FALSE;
 133     }
 134
 135   return TRUE;
 136 }
 137
 138
 139
 140 #define msdos_mkobject aout_32_mkobject
 141 #define msdos_make_empty_symbol aout_32_make_empty_symbol
 142 #define msdos_bfd_reloc_type_lookup aout_32_reloc_type_lookup
 143
 144 #define msdos_close_and_cleanup _bfd_generic_close_and_cleanup
 145 #define msdos_bfd_free_cached_info _bfd_generic_bfd_free_cached_info
 146 #define msdos_new_section_hook _bfd_generic_new_section_hook
 147 #define msdos_get_section_contents _bfd_generic_get_section_contents
 148 #define msdos_get_section_contents_in_window \
 149   _bfd_generic_get_section_contents_in_window
 150 #define msdos_bfd_get_relocated_section_contents \
 151   bfd_generic_get_relocated_section_contents
 152 #define msdos_bfd_relax_section bfd_generic_relax_section
 153 #define msdos_bfd_gc_sections bfd_generic_gc_sections
 154 #define msdos_bfd_merge_sections bfd_generic_merge_sections
 155 #define msdos_bfd_is_group_section bfd_generic_is_group_section
 156 #define msdos_bfd_discard_group bfd_generic_discard_group
 157 #define msdos_section_already_linked \
 158   _bfd_generic_section_already_linked
 159 #define msdos_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
 160 #define msdos_bfd_link_hash_table_free _bfd_generic_link_hash_table_free
 161 #define msdos_bfd_link_add_symbols _bfd_generic_link_add_symbols
 162 #define msdos_bfd_link_just_syms _bfd_generic_link_just_syms
 163 #define msdos_bfd_final_link _bfd_generic_final_link
 164 #define msdos_bfd_link_split_section _bfd_generic_link_split_section
 165 #define msdos_set_arch_mach _bfd_generic_set_arch_mach
 166
 167 #define msdos_get_symtab_upper_bound _bfd_nosymbols_get_symtab_upper_bound
 168 #define msdos_canonicalize_symtab _bfd_nosymbols_canonicalize_symtab
 169 #define msdos_print_symbol _bfd_nosymbols_print_symbol
 170 #define msdos_get_symbol_info _bfd_nosymbols_get_symbol_info
 171 #define msdos_find_nearest_line _bfd_nosymbols_find_nearest_line
 172 #define msdos_find_inliner_info _bfd_nosymbols_find_inliner_info
 173 #define msdos_get_lineno _bfd_nosymbols_get_lineno
 174 #define msdos_bfd_is_target_special_symbol ((bfd_boolean (*) (bfd *, asymbol *)) bfd_false)
 175 #define msdos_bfd_is_local_label_name _bfd_nosymbols_bfd_is_local_label_name
 176 #define msdos_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
 177 #define msdos_read_minisymbols _bfd_nosymbols_read_minisymbols
 178 #define msdos_minisymbol_to_symbol _bfd_nosymbols_minisymbol_to_symbol
 179
 180 #define msdos_canonicalize_reloc _bfd_norelocs_canonicalize_reloc
 181 #define msdos_get_reloc_upper_bound _bfd_norelocs_get_reloc_upper_bound
 182 #define msdos_32_bfd_link_split_section  _bfd_generic_link_split_section
 183
 184 const bfd_target i386msdos_vec =
 185   {
 186     "msdos",                    /* name */
 187     bfd_target_msdos_flavour,
 188     BFD_ENDIAN_LITTLE,          /* target byte order */
 189     BFD_ENDIAN_LITTLE,          /* target headers byte order */
 190     (EXEC_P),                   /* object flags */
 191     (SEC_CODE | SEC_DATA | SEC_HAS_CONTENTS
 192      | SEC_ALLOC | SEC_LOAD),   /* section flags */
 193     0,                          /* leading underscore */
 194     ' ',                                /* ar_pad_char */
 195     16,                         /* ar_max_namelen */
 196     bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 197     bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 198     bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* data */
 199     bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 200     bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 201     bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* hdrs */
 202
 203     {
 204       _bfd_dummy_target,
 205       _bfd_dummy_target,                /* bfd_check_format */
 206       _bfd_dummy_target,
 207       _bfd_dummy_target,
 208     },
 209     {
 210       bfd_false,
 211       msdos_mkobject,
 212       _bfd_generic_mkarchive,
 213       bfd_false,
 214     },
 215     {                           /* bfd_write_contents */
 216       bfd_false,
 217       msdos_write_object_contents,
 218       _bfd_write_archive_contents,
 219       bfd_false,
 220     },
 221
 222     BFD_JUMP_TABLE_GENERIC (msdos),
 223     BFD_JUMP_TABLE_COPY (_bfd_generic),
 224     BFD_JUMP_TABLE_CORE (_bfd_nocore),
 225     BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 226     BFD_JUMP_TABLE_SYMBOLS (msdos),
 227     BFD_JUMP_TABLE_RELOCS (msdos),
 228     BFD_JUMP_TABLE_WRITE (msdos),
 229     BFD_JUMP_TABLE_LINK (msdos),
 230     BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 231
 232     NULL,
 233
 234     (PTR) 0
 235   };
 236
 237