1/* BFD back-end for MS-DOS executables.
2   Copyright (C) 1990-2017 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@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
36static int
37msdos_sizeof_headers (bfd *abfd ATTRIBUTE_UNUSED,
38		      struct bfd_link_info *info ATTRIBUTE_UNUSED)
39{
40  return 0;
41}
42
43static bfd_boolean
44msdos_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
105static bfd_boolean
106msdos_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
182const 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