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@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
msdos_sizeof_headers(bfd * abfd ATTRIBUTE_UNUSED,struct bfd_link_info * info ATTRIBUTE_UNUSED)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
msdos_write_object_contents(bfd * abfd)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
msdos_set_section_contents(bfd * abfd,sec_ptr section,const void * location,file_ptr offset,bfd_size_type count)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