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
  60   PARAMS ((bfd *, bfd_boolean));
  61 static bfd_boolean msdos_write_object_contents
  62   PARAMS ((bfd *));
  63 static bfd_boolean msdos_set_section_contents
  64   PARAMS ((bfd *, sec_ptr, PTR, file_ptr, bfd_size_type));
  65
  66 static int
  67 msdos_sizeof_headers (abfd, exec)
  68      bfd *abfd ATTRIBUTE_UNUSED;
  69      bfd_boolean exec ATTRIBUTE_UNUSED;
  70 {
  71   return 0;
  72 }
  73
  74 static bfd_boolean
  75 msdos_write_object_contents (abfd)
  76      bfd *abfd;
  77 {
  78   static char hdr[EXE_PAGE_SIZE];
  79   file_ptr outfile_size = sizeof(hdr);
  80   bfd_vma high_vma = 0;
  81   asection *sec;
  82
  83   /* Find the total size of the program on disk and in memory.  */
  84   for (sec = abfd->sections; sec != (asection *) NULL; sec = sec->next)
  85     {
  86       if (bfd_get_section_size_before_reloc (sec) == 0)
  87         continue;
  88       if (bfd_get_section_flags (abfd, sec) & SEC_ALLOC)
  89         {
  90           bfd_vma sec_vma = bfd_get_section_vma (abfd, sec)
  91                             + bfd_get_section_size_before_reloc (sec);
  92           if (sec_vma > high_vma)
  93             high_vma = sec_vma;
  94         }
  95       if (bfd_get_section_flags (abfd, sec) & SEC_LOAD)
  96         {
  97           file_ptr sec_end = sizeof(hdr)
  98                              + bfd_get_section_vma (abfd, sec)
  99                              + bfd_get_section_size_before_reloc (sec);
 100           if (sec_end > outfile_size)
 101             outfile_size = sec_end;
 102         }
 103     }
 104
 105   /* Make sure the program isn't too big.  */
 106   if (high_vma > (bfd_vma)0xffff)
 107     {
 108       bfd_set_error(bfd_error_file_too_big);
 109       return FALSE;
 110     }
 111
 112   /* Constants.  */
 113   H_PUT_16 (abfd, EXE_MAGIC, &hdr[0]);
 114   H_PUT_16 (abfd, EXE_PAGE_SIZE / 16, &hdr[8]);
 115   H_PUT_16 (abfd, EXE_LOAD_LOW, &hdr[12]);
 116   H_PUT_16 (abfd, 0x3e, &hdr[24]);
 117   H_PUT_16 (abfd, 0x0001, &hdr[28]); /* XXX??? */
 118   H_PUT_16 (abfd, 0x30fb, &hdr[30]); /* XXX??? */
 119   H_PUT_16 (abfd, 0x726a, &hdr[32]); /* XXX??? */
 120
 121   /* Bytes in last page (0 = full page).  */
 122   H_PUT_16 (abfd, outfile_size & (EXE_PAGE_SIZE - 1), &hdr[2]);
 123
 124   /* Number of pages.  */
 125   H_PUT_16 (abfd, (outfile_size + EXE_PAGE_SIZE - 1) / EXE_PAGE_SIZE, &hdr[4]);
 126
 127   /* Set the initial stack pointer to the end of the bss.
 128      The program's crt0 code must relocate it to a real stack.  */
 129   H_PUT_16 (abfd, high_vma, &hdr[16]);
 130
 131   if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0
 132       || bfd_bwrite (hdr, (bfd_size_type) sizeof(hdr), abfd) != sizeof(hdr))
 133     return FALSE;
 134
 135   return TRUE;
 136 }
 137
 138 static bfd_boolean
 139 msdos_set_section_contents (abfd, section, location, offset, count)
 140      bfd *abfd;
 141      sec_ptr section;
 142      PTR location;
 143      file_ptr offset;
 144      bfd_size_type count;
 145 {
 146
 147   if (count == 0)
 148     return TRUE;
 149
 150   section->filepos = EXE_PAGE_SIZE + bfd_get_section_vma (abfd, section);
 151
 152   if (bfd_get_section_flags (abfd, section) & SEC_LOAD)
 153     {
 154       if (bfd_seek (abfd, section->filepos + offset, SEEK_SET) != 0
 155           || bfd_bwrite (location, count, abfd) != count)
 156         return FALSE;
 157     }
 158
 159   return TRUE;
 160 }
 161
 162
 163
 164 #define msdos_mkobject aout_32_mkobject
 165 #define msdos_make_empty_symbol aout_32_make_empty_symbol
 166 #define msdos_bfd_reloc_type_lookup aout_32_reloc_type_lookup
 167
 168 #define msdos_close_and_cleanup _bfd_generic_close_and_cleanup
 169 #define msdos_bfd_free_cached_info _bfd_generic_bfd_free_cached_info
 170 #define msdos_new_section_hook _bfd_generic_new_section_hook
 171 #define msdos_get_section_contents _bfd_generic_get_section_contents
 172 #define msdos_get_section_contents_in_window \
 173   _bfd_generic_get_section_contents_in_window
 174 #define msdos_bfd_get_relocated_section_contents \
 175   bfd_generic_get_relocated_section_contents
 176 #define msdos_bfd_relax_section bfd_generic_relax_section
 177 #define msdos_bfd_gc_sections bfd_generic_gc_sections
 178 #define msdos_bfd_merge_sections bfd_generic_merge_sections
 179 #define msdos_bfd_discard_group bfd_generic_discard_group
 180 #define msdos_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
 181 #define msdos_bfd_link_hash_table_free _bfd_generic_link_hash_table_free
 182 #define msdos_bfd_link_add_symbols _bfd_generic_link_add_symbols
 183 #define msdos_bfd_link_just_syms _bfd_generic_link_just_syms
 184 #define msdos_bfd_final_link _bfd_generic_final_link
 185 #define msdos_bfd_link_split_section _bfd_generic_link_split_section
 186 #define msdos_set_arch_mach _bfd_generic_set_arch_mach
 187
 188 #define msdos_get_symtab_upper_bound _bfd_nosymbols_get_symtab_upper_bound
 189 #define msdos_get_symtab _bfd_nosymbols_get_symtab
 190 #define msdos_print_symbol _bfd_nosymbols_print_symbol
 191 #define msdos_get_symbol_info _bfd_nosymbols_get_symbol_info
 192 #define msdos_find_nearest_line _bfd_nosymbols_find_nearest_line
 193 #define msdos_get_lineno _bfd_nosymbols_get_lineno
 194 #define msdos_bfd_is_local_label_name _bfd_nosymbols_bfd_is_local_label_name
 195 #define msdos_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
 196 #define msdos_read_minisymbols _bfd_nosymbols_read_minisymbols
 197 #define msdos_minisymbol_to_symbol _bfd_nosymbols_minisymbol_to_symbol
 198
 199 #define msdos_canonicalize_reloc _bfd_norelocs_canonicalize_reloc
 200 #define msdos_get_reloc_upper_bound _bfd_norelocs_get_reloc_upper_bound
 201 #define msdos_32_bfd_link_split_section  _bfd_generic_link_split_section
 202
 203 const bfd_target i386msdos_vec =
 204   {
 205     "msdos",                    /* name */
 206     bfd_target_msdos_flavour,
 207     BFD_ENDIAN_LITTLE,          /* target byte order */
 208     BFD_ENDIAN_LITTLE,          /* target headers byte order */
 209     (EXEC_P),                   /* object flags */
 210     (SEC_CODE | SEC_DATA | SEC_HAS_CONTENTS
 211      | SEC_ALLOC | SEC_LOAD),   /* section flags */
 212     0,                          /* leading underscore */
 213     ' ',                                /* ar_pad_char */
 214     16,                         /* ar_max_namelen */
 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, /* data */
 218     bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 219     bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 220     bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* hdrs */
 221
 222     {
 223       _bfd_dummy_target,
 224       _bfd_dummy_target,                /* bfd_check_format */
 225       _bfd_dummy_target,
 226       _bfd_dummy_target,
 227     },
 228     {
 229       bfd_false,
 230       msdos_mkobject,
 231       _bfd_generic_mkarchive,
 232       bfd_false,
 233     },
 234     {                           /* bfd_write_contents */
 235       bfd_false,
 236       msdos_write_object_contents,
 237       _bfd_write_archive_contents,
 238       bfd_false,
 239     },
 240
 241     BFD_JUMP_TABLE_GENERIC (msdos),
 242     BFD_JUMP_TABLE_COPY (_bfd_generic),
 243     BFD_JUMP_TABLE_CORE (_bfd_nocore),
 244     BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 245     BFD_JUMP_TABLE_SYMBOLS (msdos),
 246     BFD_JUMP_TABLE_RELOCS (msdos),
 247     BFD_JUMP_TABLE_WRITE (msdos),
 248     BFD_JUMP_TABLE_LINK (msdos),
 249     BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 250
 251     NULL,
 252
 253     (PTR) 0
 254   };
 255
 256