aboutsummaryrefslogtreecommitdiff
path: root/bfd/binary.c
blob: 458626f02a35ceb29bd416b1d2e9c4446b34d839 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
/* BFD back-end for binary objects.
   Copyright 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
   2004, 2005 Free Software Foundation, Inc.
   Written by Ian Lance Taylor, Cygnus Support, <ian@cygnus.com>

   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 2 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.  */

/* This is a BFD backend which may be used to write binary objects.
   It may only be used for output, not input.  The intention is that
   this may be used as an output format for objcopy in order to
   generate raw binary data.

   This is very simple.  The only complication is that the real data
   will start at some address X, and in some cases we will not want to
   include X zeroes just to get to that point.  Since the start
   address is not meaningful for this object file format, we use it
   instead to indicate the number of zeroes to skip at the start of
   the file.  objcopy cooperates by specially setting the start
   address to zero by default.  */

#include "bfd.h"
#include "sysdep.h"
#include "safe-ctype.h"
#include "libbfd.h"

/* Any bfd we create by reading a binary file has three symbols:
   a start symbol, an end symbol, and an absolute length symbol.  */
#define BIN_SYMS 3

/* Set by external programs - specifies the BFD architecture and
   machine number to be uses when creating binary BFDs.  */
enum bfd_architecture  bfd_external_binary_architecture = bfd_arch_unknown;
unsigned long          bfd_external_machine = 0;

/* Create a binary object.  Invoked via bfd_set_format.  */

static bfd_boolean
binary_mkobject (bfd *abfd ATTRIBUTE_UNUSED)
{
  return TRUE;
}

/* Any file may be considered to be a binary file, provided the target
   was not defaulted.  That is, it must be explicitly specified as
   being binary.  */

static const bfd_target *
binary_object_p (bfd *abfd)
{
  struct stat statbuf;
  asection *sec;

  if (abfd->target_defaulted)
    {
      bfd_set_error (bfd_error_wrong_format);
      return NULL;
    }

  abfd->symcount = BIN_SYMS;

  /* Find the file size.  */
  if (bfd_stat (abfd, &statbuf) < 0)
    {
      bfd_set_error (bfd_error_system_call);
      return NULL;
    }

  /* One data section.  */
  sec = bfd_make_section (abfd, ".data");
  if (sec == NULL)
    return NULL;
  sec->flags = SEC_ALLOC | SEC_LOAD | SEC_DATA | SEC_HAS_CONTENTS;
  sec->vma = 0;
  sec->size = statbuf.st_size;
  sec->filepos = 0;

  abfd->tdata.any = (void *) sec;

  if (bfd_get_arch_info (abfd) != NULL)
    {
      if ((bfd_get_arch_info (abfd)->arch == bfd_arch_unknown)
          && (bfd_external_binary_architecture != bfd_arch_unknown))
        bfd_set_arch_info (abfd, bfd_lookup_arch
			   (bfd_external_binary_architecture, bfd_external_machine));
    }

  return abfd->xvec;
}

#define binary_close_and_cleanup     _bfd_generic_close_and_cleanup
#define binary_bfd_free_cached_info  _bfd_generic_bfd_free_cached_info
#define binary_new_section_hook      _bfd_generic_new_section_hook

/* Get contents of the only section.  */

static bfd_boolean
binary_get_section_contents (bfd *abfd,
			     asection *section ATTRIBUTE_UNUSED,
			     void * location,
			     file_ptr offset,
			     bfd_size_type count)
{
  if (bfd_seek (abfd, offset, SEEK_SET) != 0
      || bfd_bread (location, count, abfd) != count)
    return FALSE;
  return TRUE;
}

/* Return the amount of memory needed to read the symbol table.  */

static long
binary_get_symtab_upper_bound (bfd *abfd ATTRIBUTE_UNUSED)
{
  return (BIN_SYMS + 1) * sizeof (asymbol *);
}

/* Create a symbol name based on the bfd's filename.  */

static char *
mangle_name (bfd *abfd, char *suffix)
{
  bfd_size_type size;
  char *buf;
  char *p;

  size = (strlen (bfd_get_filename (abfd))
	  + strlen (suffix)
	  + sizeof "_binary__");

  buf = bfd_alloc (abfd, size);
  if (buf == NULL)
    return "";

  sprintf (buf, "_binary_%s_%s", bfd_get_filename (abfd), suffix);

  /* Change any non-alphanumeric characters to underscores.  */
  for (p = buf; *p; p++)
    if (! ISALNUM (*p))
      *p = '_';

  return buf;
}

/* Return the symbol table.  */

static long
binary_canonicalize_symtab (bfd *abfd, asymbol **alocation)
{
  asection *sec = (asection *) abfd->tdata.any;
  asymbol *syms;
  unsigned int i;
  bfd_size_type amt = BIN_SYMS * sizeof (asymbol);

  syms = bfd_alloc (abfd, amt);
  if (syms == NULL)
    return 0;

  /* Start symbol.  */
  syms[0].the_bfd = abfd;
  syms[0].name = mangle_name (abfd, "start");
  syms[0].value = 0;
  syms[0].flags = BSF_GLOBAL;
  syms[0].section = sec;
  syms[0].udata.p = NULL;

  /* End symbol.  */
  syms[1].the_bfd = abfd;
  syms[1].name = mangle_name (abfd, "end");
  syms[1].value = sec->size;
  syms[1].flags = BSF_GLOBAL;
  syms[1].section = sec;
  syms[1].udata.p = NULL;

  /* Size symbol.  */
  syms[2].the_bfd = abfd;
  syms[2].name = mangle_name (abfd, "size");
  syms[2].value = sec->size;
  syms[2].flags = BSF_GLOBAL;
  syms[2].section = bfd_abs_section_ptr;
  syms[2].udata.p = NULL;

  for (i = 0; i < BIN_SYMS; i++)
    *alocation++ = syms++;
  *alocation = NULL;

  return BIN_SYMS;
}

#define binary_make_empty_symbol  _bfd_generic_make_empty_symbol
#define binary_print_symbol       _bfd_nosymbols_print_symbol

/* Get information about a symbol.  */

static void
binary_get_symbol_info (bfd *ignore_abfd ATTRIBUTE_UNUSED,
			asymbol *symbol,
			symbol_info *ret)
{
  bfd_symbol_info (symbol, ret);
}

#define binary_bfd_is_local_label_name      bfd_generic_is_local_label_name
#define binary_get_lineno                  _bfd_nosymbols_get_lineno
#define binary_find_nearest_line           _bfd_nosymbols_find_nearest_line
#define binary_find_inliner_info           _bfd_nosymbols_find_inliner_info
#define binary_bfd_make_debug_symbol       _bfd_nosymbols_bfd_make_debug_symbol
#define binary_read_minisymbols            _bfd_generic_read_minisymbols
#define binary_minisymbol_to_symbol        _bfd_generic_minisymbol_to_symbol
#define binary_bfd_reloc_type_lookup       _bfd_norelocs_bfd_reloc_type_lookup
#define binary_get_reloc_upper_bound        ((long (*) (bfd *, asection *)) bfd_0l)
#define binary_canonicalize_reloc           ((long (*) (bfd *, asection *, arelent **, asymbol **)) bfd_0l)
#define binary_bfd_is_target_special_symbol ((bfd_boolean (*) (bfd *, asymbol *)) bfd_false)

/* Set the architecture of a binary file.  */
#define binary_set_arch_mach _bfd_generic_set_arch_mach

/* Write section contents of a binary file.  */

static bfd_boolean
binary_set_section_contents (bfd *abfd,
			     asection *sec,
			     const void * data,
			     file_ptr offset,
			     bfd_size_type size)
{
  if (size == 0)
    return TRUE;

  if (! abfd->output_has_begun)
    {
      bfd_boolean found_low;
      bfd_vma low;
      asection *s;

      /* The lowest section LMA sets the virtual address of the start
         of the file.  We use this to set the file position of all the
         sections.  */
      found_low = FALSE;
      low = 0;
      for (s = abfd->sections; s != NULL; s = s->next)
	if (((s->flags
	      & (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC | SEC_NEVER_LOAD))
	     == (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC))
	    && (s->size > 0)
	    && (! found_low || s->lma < low))
	  {
	    low = s->lma;
	    found_low = TRUE;
	  }

      for (s = abfd->sections; s != NULL; s = s->next)
	{
	  s->filepos = s->lma - low;

	  /* Skip following warning check for sections that will not
	     occupy file space.  */
	  if ((s->flags
	       & (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_NEVER_LOAD))
	      != (SEC_HAS_CONTENTS | SEC_ALLOC)
	      || (s->size == 0))
	    continue;

	  /* If attempting to generate a binary file from a bfd with
	     LMA's all over the place, huge (sparse?) binary files may
	     result.  This condition attempts to detect this situation
	     and print a warning.  Better heuristics would be nice to
	     have.  */

	  if (s->filepos < 0)
	    (*_bfd_error_handler)
	      (_("Warning: Writing section `%s' to huge (ie negative) file offset 0x%lx."),
	       bfd_get_section_name (abfd, s),
	       (unsigned long) s->filepos);
	}

      abfd->output_has_begun = TRUE;
    }

  /* We don't want to output anything for a section that is neither
     loaded nor allocated.  The contents of such a section are not
     meaningful in the binary format.  */
  if ((sec->flags & (SEC_LOAD | SEC_ALLOC)) == 0)
    return TRUE;
  if ((sec->flags & SEC_NEVER_LOAD) != 0)
    return TRUE;

  return _bfd_generic_set_section_contents (abfd, sec, data, offset, size);
}

/* No space is required for header information.  */

static int
binary_sizeof_headers (bfd *abfd ATTRIBUTE_UNUSED,
		       bfd_boolean exec ATTRIBUTE_UNUSED)
{
  return 0;
}

#define binary_bfd_get_relocated_section_contents  bfd_generic_get_relocated_section_contents
#define binary_bfd_relax_section                   bfd_generic_relax_section
#define binary_bfd_gc_sections                     bfd_generic_gc_sections
#define binary_bfd_merge_sections                  bfd_generic_merge_sections
#define binary_bfd_is_group_section                bfd_generic_is_group_section
#define binary_bfd_discard_group                   bfd_generic_discard_group
#define binary_section_already_linked             _bfd_generic_section_already_linked
#define binary_bfd_link_hash_table_create         _bfd_generic_link_hash_table_create
#define binary_bfd_link_hash_table_free           _bfd_generic_link_hash_table_free
#define binary_bfd_link_just_syms                 _bfd_generic_link_just_syms
#define binary_bfd_link_add_symbols               _bfd_generic_link_add_symbols
#define binary_bfd_final_link                     _bfd_generic_final_link
#define binary_bfd_link_split_section             _bfd_generic_link_split_section
#define binary_get_section_contents_in_window     _bfd_generic_get_section_contents_in_window

const bfd_target binary_vec =
{
  "binary",			/* name */
  bfd_target_unknown_flavour,	/* flavour */
  BFD_ENDIAN_UNKNOWN,		/* byteorder */
  BFD_ENDIAN_UNKNOWN,		/* header_byteorder */
  EXEC_P,			/* object_flags */
  (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE | SEC_DATA
   | SEC_ROM | SEC_HAS_CONTENTS), /* section_flags */
  0,				/* symbol_leading_char */
  ' ',				/* ar_pad_char */
  16,				/* ar_max_namelen */
  bfd_getb64, bfd_getb_signed_64, bfd_putb64,
  bfd_getb32, bfd_getb_signed_32, bfd_putb32,
  bfd_getb16, bfd_getb_signed_16, bfd_putb16,	/* data */
  bfd_getb64, bfd_getb_signed_64, bfd_putb64,
  bfd_getb32, bfd_getb_signed_32, bfd_putb32,
  bfd_getb16, bfd_getb_signed_16, bfd_putb16,	/* hdrs */
  {				/* bfd_check_format */
    _bfd_dummy_target,
    binary_object_p,
    _bfd_dummy_target,
    _bfd_dummy_target,
  },
  {				/* bfd_set_format */
    bfd_false,
    binary_mkobject,
    bfd_false,
    bfd_false,
  },
  {				/* bfd_write_contents */
    bfd_false,
    bfd_true,
    bfd_false,
    bfd_false,
  },

  BFD_JUMP_TABLE_GENERIC (binary),
  BFD_JUMP_TABLE_COPY (_bfd_generic),
  BFD_JUMP_TABLE_CORE (_bfd_nocore),
  BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
  BFD_JUMP_TABLE_SYMBOLS (binary),
  BFD_JUMP_TABLE_RELOCS (binary),
  BFD_JUMP_TABLE_WRITE (binary),
  BFD_JUMP_TABLE_LINK (binary),
  BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),

  NULL,

  NULL
};