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    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 static int     msdos_sizeof_headers PARAMS ((bfd *, boolean));
  60 static boolean msdos_write_object_contents PARAMS ((bfd *));
  61 static boolean msdos_set_section_contents PARAMS ((bfd *, sec_ptr, PTR, file_ptr, bfd_size_type));
  62
  63 static int
  64 msdos_sizeof_headers (abfd, exec)
  65      bfd *abfd ATTRIBUTE_UNUSED;
  66      boolean exec ATTRIBUTE_UNUSED;
  67 {
  68   return 0;
  69 }
  70
  71 static boolean
  72 msdos_write_object_contents (abfd)
  73      bfd *abfd;
  74 {
  75   static char hdr[EXE_PAGE_SIZE];
  76   file_ptr outfile_size = sizeof(hdr);
  77   bfd_vma high_vma = 0;
  78   asection *sec;
  79
  80   /* Find the total size of the program on disk and in memory.  */
  81   for (sec = abfd->sections; sec != (asection *) NULL; sec = sec->next)
  82     {
  83       if (bfd_get_section_size_before_reloc (sec) == 0)
  84         continue;
  85       if (bfd_get_section_flags (abfd, sec) & SEC_ALLOC)
  86         {
  87           bfd_vma sec_vma = bfd_get_section_vma (abfd, sec)
  88                             + bfd_get_section_size_before_reloc (sec);
  89           if (sec_vma > high_vma)
  90             high_vma = sec_vma;
  91         }
  92       if (bfd_get_section_flags (abfd, sec) & SEC_LOAD)
  93         {
  94           file_ptr sec_end = sizeof(hdr)
  95                              + bfd_get_section_vma (abfd, sec)
  96                              + bfd_get_section_size_before_reloc (sec);
  97           if (sec_end > outfile_size)
  98             outfile_size = sec_end;
  99         }
 100     }
 101
 102   /* Make sure the program isn't too big.  */
 103   if (high_vma > (bfd_vma)0xffff)
 104     {
 105       bfd_set_error(bfd_error_file_too_big);
 106       return false;
 107     }
 108
 109   /* Constants.  */
 110   H_PUT_16 (abfd, EXE_MAGIC, &hdr[0]);
 111   H_PUT_16 (abfd, EXE_PAGE_SIZE / 16, &hdr[8]);
 112   H_PUT_16 (abfd, EXE_LOAD_LOW, &hdr[12]);
 113   H_PUT_16 (abfd, 0x3e, &hdr[24]);
 114   H_PUT_16 (abfd, 0x0001, &hdr[28]); /* XXX??? */
 115   H_PUT_16 (abfd, 0x30fb, &hdr[30]); /* XXX??? */
 116   H_PUT_16 (abfd, 0x726a, &hdr[32]); /* XXX??? */
 117
 118   /* Bytes in last page (0 = full page).  */
 119   H_PUT_16 (abfd, outfile_size & (EXE_PAGE_SIZE - 1), &hdr[2]);
 120
 121   /* Number of pages.  */
 122   H_PUT_16 (abfd, (outfile_size + EXE_PAGE_SIZE - 1) / EXE_PAGE_SIZE, &hdr[4]);
 123
 124   /* Set the initial stack pointer to the end of the bss.
 125      The program's crt0 code must relocate it to a real stack.  */
 126   H_PUT_16 (abfd, high_vma, &hdr[16]);
 127
 128   if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0
 129       || bfd_bwrite (hdr, (bfd_size_type) sizeof(hdr), abfd) != sizeof(hdr))
 130     return false;
 131
 132   return true;
 133 }
 134
 135 static boolean
 136 msdos_set_section_contents (abfd, section, location, offset, count)
 137      bfd *abfd;
 138      sec_ptr section;
 139      PTR location;
 140      file_ptr offset;
 141      bfd_size_type count;
 142 {
 143
 144   if (count == 0)
 145     return true;
 146
 147   section->filepos = EXE_PAGE_SIZE + bfd_get_section_vma (abfd, section);
 148
 149   if (bfd_get_section_flags (abfd, section) & SEC_LOAD)
 150     {
 151       if (bfd_seek (abfd, section->filepos + offset, SEEK_SET) != 0
 152           || bfd_bwrite (location, count, abfd) != count)
 153         return false;
 154     }
 155
 156   return true;
 157 }
 158
 159
 160
 161 #define msdos_mkobject aout_32_mkobject
 162 #define msdos_make_empty_symbol aout_32_make_empty_symbol
 163 #define msdos_bfd_reloc_type_lookup aout_32_reloc_type_lookup
 164
 165 #define msdos_close_and_cleanup _bfd_generic_close_and_cleanup
 166 #define msdos_bfd_free_cached_info _bfd_generic_bfd_free_cached_info
 167 #define msdos_new_section_hook _bfd_generic_new_section_hook
 168 #define msdos_get_section_contents _bfd_generic_get_section_contents
 169 #define msdos_get_section_contents_in_window \
 170   _bfd_generic_get_section_contents_in_window
 171 #define msdos_bfd_get_relocated_section_contents \
 172   bfd_generic_get_relocated_section_contents
 173 #define msdos_bfd_relax_section bfd_generic_relax_section
 174 #define msdos_bfd_gc_sections bfd_generic_gc_sections
 175 #define msdos_bfd_merge_sections bfd_generic_merge_sections
 176 #define msdos_bfd_discard_group bfd_generic_discard_group
 177 #define msdos_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
 178 #define msdos_bfd_link_hash_table_free _bfd_generic_link_hash_table_free
 179 #define msdos_bfd_link_add_symbols _bfd_generic_link_add_symbols
 180 #define msdos_bfd_link_just_syms _bfd_generic_link_just_syms
 181 #define msdos_bfd_final_link _bfd_generic_final_link
 182 #define msdos_bfd_link_split_section _bfd_generic_link_split_section
 183 #define msdos_set_arch_mach _bfd_generic_set_arch_mach
 184
 185 #define msdos_get_symtab_upper_bound _bfd_nosymbols_get_symtab_upper_bound
 186 #define msdos_get_symtab _bfd_nosymbols_get_symtab
 187 #define msdos_print_symbol _bfd_nosymbols_print_symbol
 188 #define msdos_get_symbol_info _bfd_nosymbols_get_symbol_info
 189 #define msdos_find_nearest_line _bfd_nosymbols_find_nearest_line
 190 #define msdos_get_lineno _bfd_nosymbols_get_lineno
 191 #define msdos_bfd_is_local_label_name _bfd_nosymbols_bfd_is_local_label_name
 192 #define msdos_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
 193 #define msdos_read_minisymbols _bfd_nosymbols_read_minisymbols
 194 #define msdos_minisymbol_to_symbol _bfd_nosymbols_minisymbol_to_symbol
 195
 196 #define msdos_canonicalize_reloc _bfd_norelocs_canonicalize_reloc
 197 #define msdos_get_reloc_upper_bound _bfd_norelocs_get_reloc_upper_bound
 198 #define msdos_32_bfd_link_split_section  _bfd_generic_link_split_section
 199
 200 const bfd_target i386msdos_vec =
 201   {
 202     "msdos",                    /* name */
 203     bfd_target_msdos_flavour,
 204     BFD_ENDIAN_LITTLE,          /* target byte order */
 205     BFD_ENDIAN_LITTLE,          /* target headers byte order */
 206     (EXEC_P),                   /* object flags */
 207     (SEC_CODE | SEC_DATA | SEC_HAS_CONTENTS
 208      | SEC_ALLOC | SEC_LOAD),   /* section flags */
 209     0,                          /* leading underscore */
 210     ' ',                                /* ar_pad_char */
 211     16,                         /* ar_max_namelen */
 212     bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 213     bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 214     bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* data */
 215     bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 216     bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 217     bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* hdrs */
 218
 219     {
 220       _bfd_dummy_target,
 221       _bfd_dummy_target,                /* bfd_check_format */
 222       _bfd_dummy_target,
 223       _bfd_dummy_target,
 224     },
 225     {
 226       bfd_false,
 227       msdos_mkobject,
 228       _bfd_generic_mkarchive,
 229       bfd_false,
 230     },
 231     {                           /* bfd_write_contents */
 232       bfd_false,
 233       msdos_write_object_contents,
 234       _bfd_write_archive_contents,
 235       bfd_false,
 236     },
 237
 238     BFD_JUMP_TABLE_GENERIC (msdos),
 239     BFD_JUMP_TABLE_COPY (_bfd_generic),
 240     BFD_JUMP_TABLE_CORE (_bfd_nocore),
 241     BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 242     BFD_JUMP_TABLE_SYMBOLS (msdos),
 243     BFD_JUMP_TABLE_RELOCS (msdos),
 244     BFD_JUMP_TABLE_WRITE (msdos),
 245     BFD_JUMP_TABLE_LINK (msdos),
 246     BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 247
 248     NULL,
 249
 250     (PTR) 0
 251   };
 252
 253