aboutsummaryrefslogtreecommitdiff
path: root/bfd/coff-stgo32.c
blob: 59d24275add89adf8741b35ea52af7043cb2ebd5 (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
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
/* BFD back-end for Intel 386 COFF files (DJGPP variant with a stub).
   Copyright (C) 1997-2019 Free Software Foundation, Inc.
   Written by Robert Hoehne.

   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.  */

/* This file handles now also stubbed coff images. The stub is a small
   DOS executable program before the coff image to load it in memory
   and execute it. This is needed, because DOS cannot run coff files.

   All the functions below are called by the corresponding functions
   from coffswap.h.
   The only thing what they do is to adjust the information stored in
   the COFF file which are offset into the file.
   This is needed, because DJGPP uses a very special way to load and run
   the coff image. It loads the image in memory and assumes then, that the
   image had no stub by using the filepointers as pointers in the coff
   image and NOT in the file.

   To be compatible with any existing executables I have fixed this
   here and NOT in the DJGPP startup code.  */

#define TARGET_SYM		i386_coff_go32stubbed_vec
#define TARGET_NAME		"coff-go32-exe"
#define TARGET_UNDERSCORE	'_'
#define COFF_GO32_EXE
#define COFF_LONG_SECTION_NAMES
#define COFF_SUPPORT_GNU_LINKONCE
#define COFF_LONG_FILENAMES

#define COFF_SECTION_ALIGNMENT_ENTRIES \
{ COFF_SECTION_NAME_EXACT_MATCH (".data"), \
  COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 4 }, \
{ COFF_SECTION_NAME_EXACT_MATCH (".text"), \
  COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 4 }, \
{ COFF_SECTION_NAME_PARTIAL_MATCH (".debug"), \
  COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 0 }, \
{ COFF_SECTION_NAME_PARTIAL_MATCH (".gnu.linkonce.wi"), \
  COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 0 }

#include "sysdep.h"
#include "bfd.h"

/* All that ..._PRE and ...POST functions are called from the corresponding
   coff_swap... functions. The ...PRE functions are called at the beginning
   of the function and the ...POST functions at the end of the swap routines.  */

static void
adjust_filehdr_in_post  (bfd *, void *, void *);
static void
adjust_filehdr_out_pre  (bfd *, void *, void *);
static void
adjust_filehdr_out_post  (bfd *, void *, void *);
static void
adjust_scnhdr_in_post  (bfd *, void *, void *);
static void
adjust_scnhdr_out_pre  (bfd *, void *, void *);
static void
adjust_scnhdr_out_post (bfd *, void *, void *);
static void
adjust_aux_in_post (bfd *, void *, int, int, int, int, void *);
static void
adjust_aux_out_pre (bfd *, void *, int, int, int, int, void *);
static void
adjust_aux_out_post (bfd *, void *, int, int, int, int, void *);
static void
create_go32_stub (bfd *);

#define COFF_ADJUST_FILEHDR_IN_POST adjust_filehdr_in_post
#define COFF_ADJUST_FILEHDR_OUT_PRE adjust_filehdr_out_pre
#define COFF_ADJUST_FILEHDR_OUT_POST adjust_filehdr_out_post

#define COFF_ADJUST_SCNHDR_IN_POST adjust_scnhdr_in_post
#define COFF_ADJUST_SCNHDR_OUT_PRE adjust_scnhdr_out_pre
#define COFF_ADJUST_SCNHDR_OUT_POST adjust_scnhdr_out_post

#define COFF_ADJUST_AUX_IN_POST adjust_aux_in_post
#define COFF_ADJUST_AUX_OUT_PRE adjust_aux_out_pre
#define COFF_ADJUST_AUX_OUT_POST adjust_aux_out_post

static const bfd_target *go32_check_format (bfd *);

#define COFF_CHECK_FORMAT go32_check_format

static bfd_boolean
  go32_stubbed_coff_bfd_copy_private_bfd_data (bfd *, bfd *);

#define coff_bfd_copy_private_bfd_data go32_stubbed_coff_bfd_copy_private_bfd_data

#include "coff-i386.c"

/* This macro is used, because I cannot assume the endianness of the
   host system.  */
#define _H(index) (H_GET_16 (abfd, (header + index * 2)))

/* These bytes are a 2048-byte DOS executable, which loads the COFF
   image into memory and then runs it. It is called 'stub'.  */

static const unsigned char stub_bytes[GO32_STUBSIZE] =
{
#include "go32stub.h"
};

/*
   I have not commented each swap function below, because the
   technique is in any function the same. For the ...in function,
   all the pointers are adjusted by adding GO32_STUBSIZE and for the
   ...out function, it is subtracted first and after calling the
   standard swap function it is reset to the old value.  */

/* This macro is used for adjusting the filepointers, which
   is done only, if the pointer is nonzero.  */

#define ADJUST_VAL(val,diff) \
  if (val != 0) val += diff

static void
adjust_filehdr_in_post  (bfd *  abfd ATTRIBUTE_UNUSED,
			 void * src,
			 void * dst)
{
  FILHDR *filehdr_src = (FILHDR *) src;
  struct internal_filehdr *filehdr_dst = (struct internal_filehdr *) dst;

  ADJUST_VAL (filehdr_dst->f_symptr, GO32_STUBSIZE);

  /* Save now the stub to be used later.  Put the stub data to FILEHDR_DST
     first as coff_data (abfd) still does not exist.  It may not even be ever
     created as we are just checking the file format of ABFD.  */
  memcpy (filehdr_dst->go32stub, filehdr_src->stub, GO32_STUBSIZE);
  filehdr_dst->f_flags |= F_GO32STUB;
}

static void
adjust_filehdr_out_pre  (bfd * abfd, void * in, void * out)
{
  struct internal_filehdr *filehdr_in = (struct internal_filehdr *) in;
  FILHDR *filehdr_out = (FILHDR *) out;

  /* Generate the stub.  */
  create_go32_stub (abfd);

  /* Copy the stub to the file header.  */
  if (coff_data (abfd)->go32stub != NULL)
    memcpy (filehdr_out->stub, coff_data (abfd)->go32stub, GO32_STUBSIZE);
  else
    /* Use the default.  */
    memcpy (filehdr_out->stub, stub_bytes, GO32_STUBSIZE);

  ADJUST_VAL (filehdr_in->f_symptr, -GO32_STUBSIZE);
}

static void
adjust_filehdr_out_post  (bfd *  abfd ATTRIBUTE_UNUSED,
			  void * in,
			  void * out ATTRIBUTE_UNUSED)
{
  struct internal_filehdr *filehdr_in = (struct internal_filehdr *) in;
  /* Undo the above change.  */
  ADJUST_VAL (filehdr_in->f_symptr, GO32_STUBSIZE);
}

static void
adjust_scnhdr_in_post  (bfd *  abfd ATTRIBUTE_UNUSED,
			void * ext ATTRIBUTE_UNUSED,
			void * in)
{
  struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in;

  ADJUST_VAL (scnhdr_int->s_scnptr, GO32_STUBSIZE);
  ADJUST_VAL (scnhdr_int->s_relptr, GO32_STUBSIZE);
  ADJUST_VAL (scnhdr_int->s_lnnoptr, GO32_STUBSIZE);
}

static void
adjust_scnhdr_out_pre  (bfd *  abfd ATTRIBUTE_UNUSED,
			void * in,
			void * out ATTRIBUTE_UNUSED)
{
  struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in;

  ADJUST_VAL (scnhdr_int->s_scnptr, -GO32_STUBSIZE);
  ADJUST_VAL (scnhdr_int->s_relptr, -GO32_STUBSIZE);
  ADJUST_VAL (scnhdr_int->s_lnnoptr, -GO32_STUBSIZE);
}

static void
adjust_scnhdr_out_post (bfd *  abfd ATTRIBUTE_UNUSED,
			void * in,
			void * out ATTRIBUTE_UNUSED)
{
  struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in;

  ADJUST_VAL (scnhdr_int->s_scnptr, GO32_STUBSIZE);
  ADJUST_VAL (scnhdr_int->s_relptr, GO32_STUBSIZE);
  ADJUST_VAL (scnhdr_int->s_lnnoptr, GO32_STUBSIZE);
}

static void
adjust_aux_in_post (bfd * abfd ATTRIBUTE_UNUSED,
		    void * ext1 ATTRIBUTE_UNUSED,
		    int type,
		    int in_class,
		    int indx ATTRIBUTE_UNUSED,
		    int numaux ATTRIBUTE_UNUSED,
		    void * in1)
{
  union internal_auxent *in = (union internal_auxent *) in1;

  if (in_class == C_BLOCK || in_class == C_FCN || ISFCN (type)
      || ISTAG (in_class))
    {
      ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, GO32_STUBSIZE);
    }
}

static void
adjust_aux_out_pre (bfd *abfd ATTRIBUTE_UNUSED,
		    void * inp,
		    int type,
		    int in_class,
		    int indx ATTRIBUTE_UNUSED,
		    int numaux ATTRIBUTE_UNUSED,
		    void * extp ATTRIBUTE_UNUSED)
{
  union internal_auxent *in = (union internal_auxent *) inp;

  if (in_class == C_BLOCK || in_class == C_FCN || ISFCN (type)
      || ISTAG (in_class))
    {
      ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, -GO32_STUBSIZE);
    }
}

static void
adjust_aux_out_post (bfd *abfd ATTRIBUTE_UNUSED,
		     void * inp,
		     int type,
		     int in_class,
		     int indx ATTRIBUTE_UNUSED,
		     int numaux ATTRIBUTE_UNUSED,
		     void * extp ATTRIBUTE_UNUSED)
{
  union internal_auxent *in = (union internal_auxent *) inp;

  if (in_class == C_BLOCK || in_class == C_FCN || ISFCN (type)
      || ISTAG (in_class))
    {
      ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, GO32_STUBSIZE);
    }
}

/* That's the function, which creates the stub. There are
   different cases from where the stub is taken.
   At first the environment variable $(GO32STUB) is checked and then
   $(STUB) if it was not set.
   If it exists and points to a valid stub the stub is taken from
   that file. This file can be also a whole executable file, because
   the stub is computed from the exe information at the start of that
   file.

   If there was any error, the standard stub (compiled in this file)
   is taken.  */

static void
create_go32_stub (bfd *abfd)
{
  /* Do it only once.  */
  if (coff_data (abfd)->go32stub == NULL)
    {
      char *stub;
      struct stat st;
      int f;
      unsigned char header[10];
      char magic[8];
      unsigned long coff_start;
      long exe_start;

      /* Check at first the environment variable $(GO32STUB).  */
      stub = getenv ("GO32STUB");
      /* Now check the environment variable $(STUB).  */
      if (stub == NULL)
	stub = getenv ("STUB");
      if (stub == NULL)
	goto stub_end;
      if (stat (stub, &st) != 0)
	goto stub_end;
#ifdef O_BINARY
      f = open (stub, O_RDONLY | O_BINARY);
#else
      f = open (stub, O_RDONLY);
#endif
      if (f < 0)
	goto stub_end;
      if (read (f, &header, sizeof (header)) < 0)
	{
	  close (f);
	  goto stub_end;
	}
      if (_H (0) != 0x5a4d)	/* It is not an exe file.  */
	{
	  close (f);
	  goto stub_end;
	}
      /* Compute the size of the stub (it is every thing up
	 to the beginning of the coff image).  */
      coff_start = (long) _H (2) * 512L;
      if (_H (1))
	coff_start += (long) _H (1) - 512L;

      /* Currently there is only a fixed stub size of 2048 bytes
	 supported.  */
      if (coff_start != 2048)
	{
	  close (f);
	  goto stub_end;
	}
      exe_start = _H (4) * 16;
      if ((long) lseek (f, exe_start, SEEK_SET) != exe_start)
	{
	  close (f);
	  goto stub_end;
	}
      if (read (f, &magic, 8) != 8)
	{
	  close (f);
	  goto stub_end;
	}
      if (! CONST_STRNEQ (magic, "go32stub"))
	{
	  close (f);
	  goto stub_end;
	}
      /* Now we found a correct stub (hopefully).  */
      coff_data (abfd)->go32stub = bfd_alloc (abfd, (bfd_size_type) coff_start);
      if (coff_data (abfd)->go32stub == NULL)
	{
	  close (f);
	  return;
	}
      lseek (f, 0L, SEEK_SET);
      if ((unsigned long) read (f, coff_data (abfd)->go32stub, coff_start)
	  != coff_start)
	{
	  bfd_release (abfd, coff_data (abfd)->go32stub);
	  coff_data (abfd)->go32stub = NULL;
	}
      close (f);
    }
stub_end:
  /* There was something wrong above, so use now the standard builtin
     stub.  */
  if (coff_data (abfd)->go32stub == NULL)
    {
      coff_data (abfd)->go32stub
	= bfd_alloc (abfd, (bfd_size_type) GO32_STUBSIZE);
      if (coff_data (abfd)->go32stub == NULL)
	return;
      memcpy (coff_data (abfd)->go32stub, stub_bytes, GO32_STUBSIZE);
    }
}

/* If ibfd was a stubbed coff image, copy the stub from that bfd
   to the new obfd.  */

static bfd_boolean
go32_stubbed_coff_bfd_copy_private_bfd_data (bfd *ibfd, bfd *obfd)
{
  /* Check if both are the same targets.  */
  if (ibfd->xvec != obfd->xvec)
    return TRUE;

  /* Check if we have a source stub.  */
  if (coff_data (ibfd)->go32stub == NULL)
    return TRUE;

  /* As adjust_filehdr_out_pre may get called only after this function,
     optionally allocate the output stub.  */
  if (coff_data (obfd)->go32stub == NULL)
    coff_data (obfd)->go32stub = bfd_alloc (obfd,
					  (bfd_size_type) GO32_STUBSIZE);

  /* Now copy the stub.  */
  if (coff_data (obfd)->go32stub != NULL)
    memcpy (coff_data (obfd)->go32stub, coff_data (ibfd)->go32stub,
	    GO32_STUBSIZE);

  return TRUE;
}

/* coff_object_p only checks 2 bytes F_MAGIC at GO32_STUBSIZE inside the file
   which is too fragile.  */

static const bfd_target *
go32_check_format (bfd *abfd)
{
  char mz[2];

  if (bfd_bread (mz, 2, abfd) != 2 || mz[0] != 'M' || mz[1] != 'Z')
    {
      bfd_set_error (bfd_error_wrong_format);
      return NULL;
    }

  if (bfd_seek (abfd, 0, SEEK_SET) != 0)
    return NULL;

  return coff_object_p (abfd);
}