| /* BFD back-end for MS-DOS executables. |
| Copyright (C) 1990-2021 Free Software Foundation, Inc. |
| Written by Bryan Ford of the University of Utah. |
| |
| Contributed by the Center for Software Science at the |
| University of Utah (pa-gdb-bugs@cs.utah.edu). |
| |
| This file is part of BFD, the Binary File Descriptor library. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| MA 02110-1301, USA. */ |
| |
| |
| #include "sysdep.h" |
| #include "bfd.h" |
| #include "libbfd.h" |
| #include "libaout.h" |
| #include "coff/msdos.h" |
| |
| #define EXE_LOAD_HIGH 0x0000 |
| #define EXE_LOAD_LOW 0xffff |
| #define EXE_PAGE_SIZE 512 |
| |
| static bool |
| msdos_mkobject (bfd *abfd) |
| { |
| bfd_default_set_arch_mach (abfd, bfd_arch_i386, bfd_mach_i386_i8086); |
| |
| return aout_32_mkobject (abfd); |
| } |
| |
| static bfd_cleanup |
| msdos_object_p (bfd *abfd) |
| { |
| struct external_DOS_hdr hdr; |
| bfd_byte buffer[2]; |
| asection *section; |
| bfd_size_type size; |
| |
| if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0 |
| || (size = bfd_bread (&hdr, sizeof (hdr), abfd)) + 1 < DOS_HDR_SIZE + 1) |
| { |
| if (bfd_get_error () != bfd_error_system_call) |
| bfd_set_error (bfd_error_wrong_format); |
| return NULL; |
| } |
| |
| if (H_GET_16 (abfd, hdr.e_magic) != IMAGE_DOS_SIGNATURE) |
| { |
| bfd_set_error (bfd_error_wrong_format); |
| return NULL; |
| } |
| |
| /* Check that this isn't actually a PE, NE, or LE file. If it is, the |
| e_lfanew field will be valid and point to a header beginning with one of |
| the relevant signatures. If not, e_lfanew might point to anything, so |
| don't bail if we can't read there. */ |
| if (size < offsetof (struct external_DOS_hdr, e_lfanew) + 4 |
| || H_GET_16 (abfd, hdr.e_cparhdr) < 4) |
| ; |
| else if (bfd_seek (abfd, H_GET_32 (abfd, hdr.e_lfanew), SEEK_SET) != 0 |
| || bfd_bread (buffer, (bfd_size_type) 2, abfd) != 2) |
| { |
| if (bfd_get_error () == bfd_error_system_call) |
| return NULL; |
| } |
| else |
| { |
| if (H_GET_16 (abfd, buffer) == IMAGE_NT_SIGNATURE |
| || H_GET_16 (abfd, buffer) == IMAGE_OS2_SIGNATURE |
| || H_GET_16 (abfd, buffer) == IMAGE_OS2_SIGNATURE_LE |
| || H_GET_16 (abfd, buffer) == IMAGE_OS2_SIGNATURE_LX) |
| { |
| bfd_set_error (bfd_error_wrong_format); |
| return NULL; |
| } |
| } |
| |
| if (!msdos_mkobject (abfd)) |
| return NULL; |
| |
| abfd->flags = EXEC_P; |
| abfd->start_address = H_GET_16 (abfd, hdr.e_ip); |
| |
| section = bfd_make_section (abfd, ".text"); |
| if (section == NULL) |
| return NULL; |
| |
| section->flags = (SEC_ALLOC | SEC_LOAD | SEC_CODE | SEC_HAS_CONTENTS); |
| section->filepos = H_GET_16 (abfd, hdr.e_cparhdr) * 16; |
| size = (H_GET_16 (abfd, hdr.e_cp) - 1) * EXE_PAGE_SIZE - section->filepos; |
| size += H_GET_16 (abfd, hdr.e_cblp); |
| |
| /* Check that the size is valid. */ |
| if (bfd_seek (abfd, section->filepos + size, SEEK_SET) != 0) |
| { |
| if (bfd_get_error () != bfd_error_system_call) |
| bfd_set_error (bfd_error_wrong_format); |
| return NULL; |
| } |
| |
| bfd_set_section_size (section, size); |
| section->alignment_power = 4; |
| |
| return _bfd_no_cleanup; |
| } |
| |
| static int |
| msdos_sizeof_headers (bfd *abfd ATTRIBUTE_UNUSED, |
| struct bfd_link_info *info ATTRIBUTE_UNUSED) |
| { |
| return 0; |
| } |
| |
| static bool |
| msdos_write_object_contents (bfd *abfd) |
| { |
| static char hdr[EXE_PAGE_SIZE]; |
| file_ptr outfile_size = sizeof(hdr); |
| bfd_vma high_vma = 0; |
| asection *sec; |
| |
| /* Find the total size of the program on disk and in memory. */ |
| for (sec = abfd->sections; sec != (asection *) NULL; sec = sec->next) |
| { |
| if (sec->size == 0) |
| continue; |
| if (bfd_section_flags (sec) & SEC_ALLOC) |
| { |
| bfd_vma sec_vma = bfd_section_vma (sec) + sec->size; |
| if (sec_vma > high_vma) |
| high_vma = sec_vma; |
| } |
| if (bfd_section_flags (sec) & SEC_LOAD) |
| { |
| file_ptr sec_end = (sizeof (hdr) |
| + bfd_section_vma (sec) |
| + sec->size); |
| if (sec_end > outfile_size) |
| outfile_size = sec_end; |
| } |
| } |
| |
| /* Make sure the program isn't too big. */ |
| if (high_vma > (bfd_vma)0xffff) |
| { |
| bfd_set_error(bfd_error_file_too_big); |
| return false; |
| } |
| |
| /* Constants. */ |
| H_PUT_16 (abfd, IMAGE_DOS_SIGNATURE, &hdr[0]); |
| H_PUT_16 (abfd, EXE_PAGE_SIZE / 16, &hdr[8]); |
| H_PUT_16 (abfd, EXE_LOAD_LOW, &hdr[12]); |
| H_PUT_16 (abfd, 0x3e, &hdr[24]); |
| H_PUT_16 (abfd, 0x0001, &hdr[28]); /* XXX??? */ |
| H_PUT_16 (abfd, 0x30fb, &hdr[30]); /* XXX??? */ |
| H_PUT_16 (abfd, 0x726a, &hdr[32]); /* XXX??? */ |
| |
| /* Bytes in last page (0 = full page). */ |
| H_PUT_16 (abfd, outfile_size & (EXE_PAGE_SIZE - 1), &hdr[2]); |
| |
| /* Number of pages. */ |
| H_PUT_16 (abfd, (outfile_size + EXE_PAGE_SIZE - 1) / EXE_PAGE_SIZE, &hdr[4]); |
| |
| /* Set the initial stack pointer to the end of the bss. |
| The program's crt0 code must relocate it to a real stack. */ |
| H_PUT_16 (abfd, high_vma, &hdr[16]); |
| |
| if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0 |
| || bfd_bwrite (hdr, (bfd_size_type) sizeof(hdr), abfd) != sizeof(hdr)) |
| return false; |
| |
| return true; |
| } |
| |
| static bool |
| msdos_set_section_contents (bfd *abfd, |
| sec_ptr section, |
| const void *location, |
| file_ptr offset, |
| bfd_size_type count) |
| { |
| |
| if (count == 0) |
| return true; |
| |
| section->filepos = EXE_PAGE_SIZE + bfd_section_vma (section); |
| |
| if (bfd_section_flags (section) & SEC_LOAD) |
| { |
| if (bfd_seek (abfd, section->filepos + offset, SEEK_SET) != 0 |
| || bfd_bwrite (location, count, abfd) != count) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| |
| |
| #define msdos_make_empty_symbol aout_32_make_empty_symbol |
| #define msdos_bfd_reloc_type_lookup aout_32_reloc_type_lookup |
| #define msdos_bfd_reloc_name_lookup aout_32_reloc_name_lookup |
| |
| #define msdos_close_and_cleanup _bfd_generic_close_and_cleanup |
| #define msdos_bfd_free_cached_info _bfd_generic_bfd_free_cached_info |
| #define msdos_new_section_hook _bfd_generic_new_section_hook |
| #define msdos_get_section_contents _bfd_generic_get_section_contents |
| #define msdos_get_section_contents_in_window \ |
| _bfd_generic_get_section_contents_in_window |
| #define msdos_bfd_get_relocated_section_contents \ |
| bfd_generic_get_relocated_section_contents |
| #define msdos_bfd_relax_section bfd_generic_relax_section |
| #define msdos_bfd_gc_sections bfd_generic_gc_sections |
| #define msdos_bfd_lookup_section_flags bfd_generic_lookup_section_flags |
| #define msdos_bfd_merge_sections bfd_generic_merge_sections |
| #define msdos_bfd_is_group_section bfd_generic_is_group_section |
| #define msdos_bfd_group_name bfd_generic_group_name |
| #define msdos_bfd_discard_group bfd_generic_discard_group |
| #define msdos_section_already_linked \ |
| _bfd_generic_section_already_linked |
| #define msdos_bfd_define_common_symbol bfd_generic_define_common_symbol |
| #define msdos_bfd_link_hide_symbol _bfd_generic_link_hide_symbol |
| #define msdos_bfd_define_start_stop bfd_generic_define_start_stop |
| #define msdos_bfd_link_hash_table_create _bfd_generic_link_hash_table_create |
| #define msdos_bfd_link_add_symbols _bfd_generic_link_add_symbols |
| #define msdos_bfd_link_just_syms _bfd_generic_link_just_syms |
| #define msdos_bfd_copy_link_hash_symbol_type \ |
| _bfd_generic_copy_link_hash_symbol_type |
| #define msdos_bfd_final_link _bfd_generic_final_link |
| #define msdos_bfd_link_split_section _bfd_generic_link_split_section |
| #define msdos_set_arch_mach _bfd_generic_set_arch_mach |
| #define msdos_bfd_link_check_relocs _bfd_generic_link_check_relocs |
| |
| #define msdos_get_symtab_upper_bound _bfd_nosymbols_get_symtab_upper_bound |
| #define msdos_canonicalize_symtab _bfd_nosymbols_canonicalize_symtab |
| #define msdos_print_symbol _bfd_nosymbols_print_symbol |
| #define msdos_get_symbol_info _bfd_nosymbols_get_symbol_info |
| #define msdos_get_symbol_version_string \ |
| _bfd_nosymbols_get_symbol_version_string |
| #define msdos_find_nearest_line _bfd_nosymbols_find_nearest_line |
| #define msdos_find_line _bfd_nosymbols_find_line |
| #define msdos_find_inliner_info _bfd_nosymbols_find_inliner_info |
| #define msdos_get_lineno _bfd_nosymbols_get_lineno |
| #define msdos_bfd_is_target_special_symbol _bfd_bool_bfd_asymbol_false |
| #define msdos_bfd_is_local_label_name _bfd_nosymbols_bfd_is_local_label_name |
| #define msdos_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol |
| #define msdos_read_minisymbols _bfd_nosymbols_read_minisymbols |
| #define msdos_minisymbol_to_symbol _bfd_nosymbols_minisymbol_to_symbol |
| |
| #define msdos_canonicalize_reloc _bfd_norelocs_canonicalize_reloc |
| #define msdos_set_reloc _bfd_norelocs_set_reloc |
| #define msdos_get_reloc_upper_bound _bfd_norelocs_get_reloc_upper_bound |
| #define msdos_32_bfd_link_split_section _bfd_generic_link_split_section |
| |
| const bfd_target i386_msdos_vec = |
| { |
| "msdos", /* name */ |
| bfd_target_msdos_flavour, |
| BFD_ENDIAN_LITTLE, /* target byte order */ |
| BFD_ENDIAN_LITTLE, /* target headers byte order */ |
| (EXEC_P), /* object flags */ |
| (SEC_CODE | SEC_DATA | SEC_HAS_CONTENTS |
| | SEC_ALLOC | SEC_LOAD), /* section flags */ |
| 0, /* leading underscore */ |
| ' ', /* ar_pad_char */ |
| 16, /* ar_max_namelen */ |
| 0, /* match priority. */ |
| TARGET_KEEP_UNUSED_SECTION_SYMBOLS, /* keep unused section symbols. */ |
| bfd_getl64, bfd_getl_signed_64, bfd_putl64, |
| bfd_getl32, bfd_getl_signed_32, bfd_putl32, |
| bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* data */ |
| bfd_getl64, bfd_getl_signed_64, bfd_putl64, |
| bfd_getl32, bfd_getl_signed_32, bfd_putl32, |
| bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* hdrs */ |
| |
| { |
| _bfd_dummy_target, |
| msdos_object_p, /* bfd_check_format */ |
| _bfd_dummy_target, |
| _bfd_dummy_target, |
| }, |
| { |
| _bfd_bool_bfd_false_error, |
| msdos_mkobject, |
| _bfd_generic_mkarchive, |
| _bfd_bool_bfd_false_error, |
| }, |
| { /* bfd_write_contents */ |
| _bfd_bool_bfd_false_error, |
| msdos_write_object_contents, |
| _bfd_write_archive_contents, |
| _bfd_bool_bfd_false_error, |
| }, |
| |
| BFD_JUMP_TABLE_GENERIC (msdos), |
| BFD_JUMP_TABLE_COPY (_bfd_generic), |
| BFD_JUMP_TABLE_CORE (_bfd_nocore), |
| BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive), |
| BFD_JUMP_TABLE_SYMBOLS (msdos), |
| BFD_JUMP_TABLE_RELOCS (msdos), |
| BFD_JUMP_TABLE_WRITE (msdos), |
| BFD_JUMP_TABLE_LINK (msdos), |
| BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic), |
| |
| NULL, |
| |
| NULL |
| }; |
| |
| |