1 /* BFD back-end for MS-DOS executables. 2 Copyright (C) 1990-2016 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 (at) 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 3 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., 51 Franklin Street - Fifth Floor, Boston, 23 MA 02110-1301, USA. */ 24 25 26 #include "sysdep.h" 27 #include "bfd.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 37 msdos_sizeof_headers (bfd *abfd ATTRIBUTE_UNUSED, 38 struct bfd_link_info *info ATTRIBUTE_UNUSED) 39 { 40 return 0; 41 } 42 43 static bfd_boolean 44 msdos_write_object_contents (bfd *abfd) 45 { 46 static char hdr[EXE_PAGE_SIZE]; 47 file_ptr outfile_size = sizeof(hdr); 48 bfd_vma high_vma = 0; 49 asection *sec; 50 51 /* Find the total size of the program on disk and in memory. */ 52 for (sec = abfd->sections; sec != (asection *) NULL; sec = sec->next) 53 { 54 if (sec->size == 0) 55 continue; 56 if (bfd_get_section_flags (abfd, sec) & SEC_ALLOC) 57 { 58 bfd_vma sec_vma = bfd_get_section_vma (abfd, sec) + sec->size; 59 if (sec_vma > high_vma) 60 high_vma = sec_vma; 61 } 62 if (bfd_get_section_flags (abfd, sec) & SEC_LOAD) 63 { 64 file_ptr sec_end = (sizeof (hdr) 65 + bfd_get_section_vma (abfd, sec) 66 + sec->size); 67 if (sec_end > outfile_size) 68 outfile_size = sec_end; 69 } 70 } 71 72 /* Make sure the program isn't too big. */ 73 if (high_vma > (bfd_vma)0xffff) 74 { 75 bfd_set_error(bfd_error_file_too_big); 76 return FALSE; 77 } 78 79 /* Constants. */ 80 H_PUT_16 (abfd, EXE_MAGIC, &hdr[0]); 81 H_PUT_16 (abfd, EXE_PAGE_SIZE / 16, &hdr[8]); 82 H_PUT_16 (abfd, EXE_LOAD_LOW, &hdr[12]); 83 H_PUT_16 (abfd, 0x3e, &hdr[24]); 84 H_PUT_16 (abfd, 0x0001, &hdr[28]); /* XXX??? */ 85 H_PUT_16 (abfd, 0x30fb, &hdr[30]); /* XXX??? */ 86 H_PUT_16 (abfd, 0x726a, &hdr[32]); /* XXX??? */ 87 88 /* Bytes in last page (0 = full page). */ 89 H_PUT_16 (abfd, outfile_size & (EXE_PAGE_SIZE - 1), &hdr[2]); 90 91 /* Number of pages. */ 92 H_PUT_16 (abfd, (outfile_size + EXE_PAGE_SIZE - 1) / EXE_PAGE_SIZE, &hdr[4]); 93 94 /* Set the initial stack pointer to the end of the bss. 95 The program's crt0 code must relocate it to a real stack. */ 96 H_PUT_16 (abfd, high_vma, &hdr[16]); 97 98 if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0 99 || bfd_bwrite (hdr, (bfd_size_type) sizeof(hdr), abfd) != sizeof(hdr)) 100 return FALSE; 101 102 return TRUE; 103 } 104 105 static bfd_boolean 106 msdos_set_section_contents (bfd *abfd, 107 sec_ptr section, 108 const void *location, 109 file_ptr offset, 110 bfd_size_type count) 111 { 112 113 if (count == 0) 114 return TRUE; 115 116 section->filepos = EXE_PAGE_SIZE + bfd_get_section_vma (abfd, section); 117 118 if (bfd_get_section_flags (abfd, section) & SEC_LOAD) 119 { 120 if (bfd_seek (abfd, section->filepos + offset, SEEK_SET) != 0 121 || bfd_bwrite (location, count, abfd) != count) 122 return FALSE; 123 } 124 125 return TRUE; 126 } 127 128 129 130 #define msdos_mkobject aout_32_mkobject 131 #define msdos_make_empty_symbol aout_32_make_empty_symbol 132 #define msdos_bfd_reloc_type_lookup aout_32_reloc_type_lookup 133 #define msdos_bfd_reloc_name_lookup aout_32_reloc_name_lookup 134 135 #define msdos_close_and_cleanup _bfd_generic_close_and_cleanup 136 #define msdos_bfd_free_cached_info _bfd_generic_bfd_free_cached_info 137 #define msdos_new_section_hook _bfd_generic_new_section_hook 138 #define msdos_get_section_contents _bfd_generic_get_section_contents 139 #define msdos_get_section_contents_in_window \ 140 _bfd_generic_get_section_contents_in_window 141 #define msdos_bfd_get_relocated_section_contents \ 142 bfd_generic_get_relocated_section_contents 143 #define msdos_bfd_relax_section bfd_generic_relax_section 144 #define msdos_bfd_gc_sections bfd_generic_gc_sections 145 #define msdos_bfd_lookup_section_flags bfd_generic_lookup_section_flags 146 #define msdos_bfd_merge_sections bfd_generic_merge_sections 147 #define msdos_bfd_is_group_section bfd_generic_is_group_section 148 #define msdos_bfd_discard_group bfd_generic_discard_group 149 #define msdos_section_already_linked \ 150 _bfd_generic_section_already_linked 151 #define msdos_bfd_define_common_symbol bfd_generic_define_common_symbol 152 #define msdos_bfd_link_hash_table_create _bfd_generic_link_hash_table_create 153 #define msdos_bfd_link_add_symbols _bfd_generic_link_add_symbols 154 #define msdos_bfd_link_just_syms _bfd_generic_link_just_syms 155 #define msdos_bfd_copy_link_hash_symbol_type \ 156 _bfd_generic_copy_link_hash_symbol_type 157 #define msdos_bfd_final_link _bfd_generic_final_link 158 #define msdos_bfd_link_split_section _bfd_generic_link_split_section 159 #define msdos_set_arch_mach _bfd_generic_set_arch_mach 160 #define msdos_bfd_link_check_relocs _bfd_generic_link_check_relocs 161 162 #define msdos_get_symtab_upper_bound _bfd_nosymbols_get_symtab_upper_bound 163 #define msdos_canonicalize_symtab _bfd_nosymbols_canonicalize_symtab 164 #define msdos_print_symbol _bfd_nosymbols_print_symbol 165 #define msdos_get_symbol_info _bfd_nosymbols_get_symbol_info 166 #define msdos_get_symbol_version_string \ 167 _bfd_nosymbols_get_symbol_version_string 168 #define msdos_find_nearest_line _bfd_nosymbols_find_nearest_line 169 #define msdos_find_line _bfd_nosymbols_find_line 170 #define msdos_find_inliner_info _bfd_nosymbols_find_inliner_info 171 #define msdos_get_lineno _bfd_nosymbols_get_lineno 172 #define msdos_bfd_is_target_special_symbol ((bfd_boolean (*) (bfd *, asymbol *)) bfd_false) 173 #define msdos_bfd_is_local_label_name _bfd_nosymbols_bfd_is_local_label_name 174 #define msdos_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol 175 #define msdos_read_minisymbols _bfd_nosymbols_read_minisymbols 176 #define msdos_minisymbol_to_symbol _bfd_nosymbols_minisymbol_to_symbol 177 178 #define msdos_canonicalize_reloc _bfd_norelocs_canonicalize_reloc 179 #define msdos_get_reloc_upper_bound _bfd_norelocs_get_reloc_upper_bound 180 #define msdos_32_bfd_link_split_section _bfd_generic_link_split_section 181 182 const bfd_target i386_msdos_vec = 183 { 184 "msdos", /* name */ 185 bfd_target_msdos_flavour, 186 BFD_ENDIAN_LITTLE, /* target byte order */ 187 BFD_ENDIAN_LITTLE, /* target headers byte order */ 188 (EXEC_P), /* object flags */ 189 (SEC_CODE | SEC_DATA | SEC_HAS_CONTENTS 190 | SEC_ALLOC | SEC_LOAD), /* section flags */ 191 0, /* leading underscore */ 192 ' ', /* ar_pad_char */ 193 16, /* ar_max_namelen */ 194 0, /* match priority. */ 195 bfd_getl64, bfd_getl_signed_64, bfd_putl64, 196 bfd_getl32, bfd_getl_signed_32, bfd_putl32, 197 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* data */ 198 bfd_getl64, bfd_getl_signed_64, bfd_putl64, 199 bfd_getl32, bfd_getl_signed_32, bfd_putl32, 200 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* hdrs */ 201 202 { 203 _bfd_dummy_target, 204 _bfd_dummy_target, /* bfd_check_format */ 205 _bfd_dummy_target, 206 _bfd_dummy_target, 207 }, 208 { 209 bfd_false, 210 msdos_mkobject, 211 _bfd_generic_mkarchive, 212 bfd_false, 213 }, 214 { /* bfd_write_contents */ 215 bfd_false, 216 msdos_write_object_contents, 217 _bfd_write_archive_contents, 218 bfd_false, 219 }, 220 221 BFD_JUMP_TABLE_GENERIC (msdos), 222 BFD_JUMP_TABLE_COPY (_bfd_generic), 223 BFD_JUMP_TABLE_CORE (_bfd_nocore), 224 BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive), 225 BFD_JUMP_TABLE_SYMBOLS (msdos), 226 BFD_JUMP_TABLE_RELOCS (msdos), 227 BFD_JUMP_TABLE_WRITE (msdos), 228 BFD_JUMP_TABLE_LINK (msdos), 229 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic), 230 231 NULL, 232 233 NULL 234 }; 235 236 237
