1 /* rescoff.c -- read and write resources in Windows COFF files.
2    Copyright 1997, 1998, 1999, 2000, 2003
3    Free Software Foundation, Inc.
4    Written by Ian Lance Taylor, Cygnus Support.
5 
6    This file is part of GNU Binutils.
7 
8    This program is free software; you can redistribute it and/or modify
9    it under the terms of the GNU General Public License as published by
10    the Free Software Foundation; either version 2 of the License, or
objc_msgSendobjc_object11    (at your option) any later version.
12 
13    This program is distributed in the hope that it will be useful,
14    but WITHOUT ANY WARRANTY; without even the implied warranty of
15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16    GNU General Public License for more details.
17 
18    You should have received a copy of the GNU General Public License
19    along with this program; if not, write to the Free Software
20    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
21    02111-1307, USA.  */
22 
23 /* This file contains function that read and write Windows resources
24    in COFF files.  */
25 
26 #include "bfd.h"
27 #include "bucomm.h"
28 #include "libiberty.h"
29 #include "windres.h"
30 
31 #include <assert.h>
32 
33 /* In order to use the address of a resource data entry, we need to
34    get the image base of the file.  Right now we extract it from
35    internal BFD information.  FIXME.  */
36 
37 #include "coff/internal.h"
38 #include "libcoff.h"
39 
40 /* Information we extract from the file.  */
41 
42 struct coff_file_info
43 {
44   /* File name.  */
45   const char *filename;
46   /* Data read from the file.  */
47   const bfd_byte *data;
48   /* End of data read from file.  */
49   const bfd_byte *data_end;
50   /* Address of the resource section minus the image base of the file.  */
51   bfd_vma secaddr;
52   /* Non-zero if the file is big endian.  */
53   int big_endian;
54 };
55 
56 /* A resource directory table in a COFF file.  */
57 
58 struct extern_res_directory
59 {
60   /* Characteristics.  */
61   bfd_byte characteristics[4];
62   /* Time stamp.  */
63   bfd_byte time[4];
64   /* Major version number.  */
65   bfd_byte major[2];
66   /* Minor version number.  */
67   bfd_byte minor[2];
68   /* Number of named directory entries.  */
69   bfd_byte name_count[2];
70   /* Number of directory entries with IDs.  */
71   bfd_byte id_count[2];
72 };
73 
74 /* A resource directory entry in a COFF file.  */
75 
76 struct extern_res_entry
77 {
78   /* Name or ID.  */
79   bfd_byte name[4];
80   /* Address of resource entry or subdirectory.  */
81   bfd_byte rva[4];
82 };
83 
84 /* A resource data entry in a COFF file.  */
85 
86 struct extern_res_data
87 {
88   /* Address of resource data.  This is apparently a file relative
89      address, rather than a section offset.  */
90   bfd_byte rva[4];
91   /* Size of resource data.  */
92   bfd_byte size[4];
93   /* Code page.  */
94   bfd_byte codepage[4];
95   /* Reserved.  */
96   bfd_byte reserved[4];
97 };
98 
99 /* Macros to swap in values.  */
100 
101 #define getfi_16(fi, s) ((fi)->big_endian ? bfd_getb16 (s) : bfd_getl16 (s))
102 #define getfi_32(fi, s) ((fi)->big_endian ? bfd_getb32 (s) : bfd_getl32 (s))
103 
104 /* Local functions.  */
105 
106 static void overrun (const struct coff_file_info *, const char *);
107 static struct res_directory *read_coff_res_dir
108   (const bfd_byte *, const struct coff_file_info *,
109    const struct res_id *, int);
110 static struct res_resource *read_coff_data_entry
111   (const bfd_byte *, const struct coff_file_info *, const struct res_id *);
112 
113 /* Read the resources in a COFF file.  */
114 
115 struct res_directory *
116 read_coff_rsrc (const char *filename, const char *target)
117 {
118   bfd *abfd;
119   char **matching;
120   asection *sec;
121   bfd_size_type size;
122   bfd_byte *data;
123   struct coff_file_info finfo;
124 
125   if (filename == NULL)
126     fatal (_("filename required for COFF input"));
127 
128   abfd = bfd_openr (filename, target);
129   if (abfd == NULL)
130     bfd_fatal (filename);
131 
132   if (! bfd_check_format_matches (abfd, bfd_object, &matching))
133     {
134       bfd_nonfatal (bfd_get_filename (abfd));
135       if (bfd_get_error () == bfd_error_file_ambiguously_recognized)
136 	list_matching_formats (matching);
137       xexit (1);
138     }
139 
140   sec = bfd_get_section_by_name (abfd, ".rsrc");
141   if (sec == NULL)
142     {
143       fatal (_("%s: no resource section"), filename);
144     }
145 
146   size = bfd_section_size (abfd, sec);
147   data = (bfd_byte *) res_alloc (size);
148 
149   if (! bfd_get_section_contents (abfd, sec, data, 0, size))
150     bfd_fatal (_("can't read resource section"));
151 
152   finfo.filename = filename;
153   finfo.data = data;
154   finfo.data_end = data + size;
155   finfo.secaddr = (bfd_get_section_vma (abfd, sec)
156 		   - pe_data (abfd)->pe_opthdr.ImageBase);
157   finfo.big_endian = bfd_big_endian (abfd);
158 
159   bfd_close (abfd);
160 
161   /* Now just read in the top level resource directory.  Note that we
162      don't free data, since we create resource entries that point into
163      it.  If we ever want to free up the resource information we read,
164      this will have to be cleaned up.  */
165 
166   return read_coff_res_dir (data, &finfo, (const struct res_id *) NULL, 0);
167 }
168 
169 /* Give an error if we are out of bounds.  */
170 
171 static void
172 overrun (const struct coff_file_info *finfo, const char *msg)
173 {
174   fatal (_("%s: %s: address out of bounds"), finfo->filename, msg);
175 }
176 
177 /* Read a resource directory.  */
178 
179 static struct res_directory *
180 read_coff_res_dir (const bfd_byte *data, const struct coff_file_info *finfo,
181 		   const struct res_id *type, int level)
182 {
183   const struct extern_res_directory *erd;
184   struct res_directory *rd;
185   int name_count, id_count, i;
186   struct res_entry **pp;
187   const struct extern_res_entry *ere;
188 
189   if ((size_t) (finfo->data_end - data) < sizeof (struct extern_res_directory))
190     overrun (finfo, _("directory"));
191 
192   erd = (const struct extern_res_directory *) data;
193 
194   rd = (struct res_directory *) res_alloc (sizeof *rd);
195   rd->characteristics = getfi_32 (finfo, erd->characteristics);
196   rd->time = getfi_32 (finfo, erd->time);
197   rd->major = getfi_16 (finfo, erd->major);
198   rd->minor = getfi_16 (finfo, erd->minor);
199   rd->entries = NULL;
200 
201   name_count = getfi_16 (finfo, erd->name_count);
202   id_count = getfi_16 (finfo, erd->id_count);
203 
204   pp = &rd->entries;
205 
206   /* The resource directory entries immediately follow the directory
207      table.  */
208   ere = (const struct extern_res_entry *) (erd + 1);
209 
210   for (i = 0; i < name_count; i++, ere++)
211     {
212       unsigned long name, rva;
213       struct res_entry *re;
214       const bfd_byte *ers;
215       int length, j;
216 
217       if ((const bfd_byte *) ere >= finfo->data_end)
218 	overrun (finfo, _("named directory entry"));
219 
220       name = getfi_32 (finfo, ere->name);
221       rva = getfi_32 (finfo, ere->rva);
222 
223       /* For some reason the high bit in NAME is set.  */
224       name &=~ 0x80000000;
225 
226       if (name > (size_t) (finfo->data_end - finfo->data))
227 	overrun (finfo, _("directory entry name"));
228 
229       ers = finfo->data + name;
230 
231       re = (struct res_entry *) res_alloc (sizeof *re);
232       re->next = NULL;
233       re->id.named = 1;
234       length = getfi_16 (finfo, ers);
235       re->id.u.n.length = length;
236       re->id.u.n.name = (unichar *) res_alloc (length * sizeof (unichar));
237       for (j = 0; j < length; j++)
238 	re->id.u.n.name[j] = getfi_16 (finfo, ers + j * 2 + 2);
239 
240       if (level == 0)
241 	type = &re->id;
242 
243       if ((rva & 0x80000000) != 0)
244 	{
245 	  rva &=~ 0x80000000;
246 	  if (rva >= (size_t) (finfo->data_end - finfo->data))
247 	    overrun (finfo, _("named subdirectory"));
248 	  re->subdir = 1;
249 	  re->u.dir = read_coff_res_dir (finfo->data + rva, finfo, type,
250 					 level + 1);
251 	}
252       else
253 	{
254 	  if (rva >= (size_t) (finfo->data_end - finfo->data))
255 	    overrun (finfo, _("named resource"));
256 	  re->subdir = 0;
257 	  re->u.res = read_coff_data_entry (finfo->data + rva, finfo, type);
258 	}
259 
260       *pp = re;
261       pp = &re->next;
262     }
263 
264   for (i = 0; i < id_count; i++, ere++)
265     {
266       unsigned long name, rva;
267       struct res_entry *re;
268 
269       if ((const bfd_byte *) ere >= finfo->data_end)
270 	overrun (finfo, _("ID directory entry"));
271 
272       name = getfi_32 (finfo, ere->name);
273       rva = getfi_32 (finfo, ere->rva);
274 
275       re = (struct res_entry *) res_alloc (sizeof *re);
276       re->next = NULL;
277       re->id.named = 0;
278       re->id.u.id = name;
279 
280       if (level == 0)
281 	type = &re->id;
282 
283       if ((rva & 0x80000000) != 0)
284 	{
285 	  rva &=~ 0x80000000;
286 	  if (rva >= (size_t) (finfo->data_end - finfo->data))
287 	    overrun (finfo, _("ID subdirectory"));
288 	  re->subdir = 1;
289 	  re->u.dir = read_coff_res_dir (finfo->data + rva, finfo, type,
290 					 level + 1);
291 	}
292       else
293 	{
294 	  if (rva >= (size_t) (finfo->data_end - finfo->data))
295 	    overrun (finfo, _("ID resource"));
296 	  re->subdir = 0;
297 	  re->u.res = read_coff_data_entry (finfo->data + rva, finfo, type);
298 	}
299 
300       *pp = re;
301       pp = &re->next;
302     }
303 
304   return rd;
305 }
306 
307 /* Read a resource data entry.  */
308 
309 static struct res_resource *
310 read_coff_data_entry (const bfd_byte *data, const struct coff_file_info *finfo, const struct res_id *type)
311 {
312   const struct extern_res_data *erd;
313   struct res_resource *r;
314   unsigned long size, rva;
315   const bfd_byte *resdata;
316 
317   if (type == NULL)
318     fatal (_("resource type unknown"));
319 
320   if ((size_t) (finfo->data_end - data) < sizeof (struct extern_res_data))
321     overrun (finfo, _("data entry"));
322 
323   erd = (const struct extern_res_data *) data;
324 
325   size = getfi_32 (finfo, erd->size);
326   rva = getfi_32 (finfo, erd->rva);
327   if (rva < finfo->secaddr
328       || rva - finfo->secaddr >= (size_t) (finfo->data_end - finfo->data))
329     overrun (finfo, _("resource data"));
330 
331   resdata = finfo->data + (rva - finfo->secaddr);
332 
333   if (size > (size_t) (finfo->data_end - resdata))
334     overrun (finfo, _("resource data size"));
335 
336   r = bin_to_res (*type, resdata, size, finfo->big_endian);
337 
338   memset (&r->res_info, 0, sizeof (struct res_res_info));
339   r->coff_info.codepage = getfi_32 (finfo, erd->codepage);
340   r->coff_info.reserved = getfi_32 (finfo, erd->reserved);
341 
342   return r;
343 }
344 
345 /* This structure is used to build a list of bindata structures.  */
346 
347 struct bindata_build
348 {
349   /* The data.  */
350   struct bindata *d;
351   /* The last structure we have added to the list.  */
352   struct bindata *last;
353   /* The size of the list as a whole.  */
354   unsigned long length;
355 };
356 
357 /* This structure keeps track of information as we build the directory
358    tree.  */
359 
360 struct coff_write_info
361 {
362   /* These fields are based on the BFD.  */
363   /* The BFD itself.  */
364   bfd *abfd;
365   /* Non-zero if the file is big endian.  */
366   int big_endian;
367   /* Pointer to section symbol used to build RVA relocs.  */
368   asymbol **sympp;
369 
370   /* These fields are computed initially, and then not changed.  */
371   /* Length of directory tables and entries.  */
372   unsigned long dirsize;
373   /* Length of directory entry strings.  */
374   unsigned long dirstrsize;
375   /* Length of resource data entries.  */
376   unsigned long dataentsize;
377 
378   /* These fields are updated as we add data.  */
379   /* Directory tables and entries.  */
380   struct bindata_build dirs;
381   /* Directory entry strings.  */
382   struct bindata_build dirstrs;
383   /* Resource data entries.  */
384   struct bindata_build dataents;
385   /* Actual resource data.  */
386   struct bindata_build resources;
387   /* Relocations.  */
388   arelent **relocs;
389   /* Number of relocations.  */
390   unsigned int reloc_count;
391 };
392 
393 /* Macros to swap out values.  */
394 
395 #define putcwi_16(cwi, v, s) \
396   ((cwi->big_endian) ? bfd_putb16 ((v), (s)) : bfd_putl16 ((v), (s)))
397 #define putcwi_32(cwi, v, s) \
398   ((cwi->big_endian) ? bfd_putb32 ((v), (s)) : bfd_putl32 ((v), (s)))
399 
400 static void coff_bin_sizes
401   (const struct res_directory *, struct coff_write_info *);
402 static unsigned char *coff_alloc (struct bindata_build *, size_t);
403 static void coff_to_bin
404   (const struct res_directory *, struct coff_write_info *);
405 static void coff_res_to_bin
406   (const struct res_resource *, struct coff_write_info *);
407 
408 /* Write resources to a COFF file.  RESOURCES should already be
409    sorted.
410 
411    Right now we always create a new file.  Someday we should also
412    offer the ability to merge resources into an existing file.  This
413    would require doing the basic work of objcopy, just modifying or
414    adding the .rsrc section.  */
415 
416 void
417 write_coff_file (const char *filename, const char *target,
418 		 const struct res_directory *resources)
419 {
420   bfd *abfd;
421   asection *sec;
422   struct coff_write_info cwi;
423   struct bindata *d;
424   unsigned long length, offset;
425 
426   if (filename == NULL)
427     fatal (_("filename required for COFF output"));
428 
429   abfd = bfd_openw (filename, target);
430   if (abfd == NULL)
431     bfd_fatal (filename);
432 
433   if (! bfd_set_format (abfd, bfd_object))
434     bfd_fatal ("bfd_set_format");
435 
436 #if defined DLLTOOL_SH
437   if (! bfd_set_arch_mach (abfd, bfd_arch_sh, 0))
438     bfd_fatal ("bfd_set_arch_mach(sh)");
439 #elif defined DLLTOOL_MIPS
440   if (! bfd_set_arch_mach (abfd, bfd_arch_mips, 0))
441     bfd_fatal ("bfd_set_arch_mach(mips)");
442 #elif defined DLLTOOL_ARM
443   if (! bfd_set_arch_mach (abfd, bfd_arch_arm, 0))
444     bfd_fatal ("bfd_set_arch_mach(arm)");
445 #else
446   /* FIXME: This is obviously i386 specific.  */
447   if (! bfd_set_arch_mach (abfd, bfd_arch_i386, 0))
448     bfd_fatal ("bfd_set_arch_mach(i386)");
449 #endif
450 
451   if (! bfd_set_file_flags (abfd, HAS_SYMS | HAS_RELOC))
452     bfd_fatal ("bfd_set_file_flags");
453 
454   sec = bfd_make_section (abfd, ".rsrc");
455   if (sec == NULL)
456     bfd_fatal ("bfd_make_section");
457 
458   if (! bfd_set_section_flags (abfd, sec,
459 			       (SEC_HAS_CONTENTS | SEC_ALLOC
460 				| SEC_LOAD | SEC_DATA)))
461     bfd_fatal ("bfd_set_section_flags");
462 
463   if (! bfd_set_symtab (abfd, sec->symbol_ptr_ptr, 1))
464     bfd_fatal ("bfd_set_symtab");
465 
466   /* Requiring this is probably a bug in BFD.  */
467   sec->output_section = sec;
468 
469   /* The order of data in the .rsrc section is
470        resource directory tables and entries
471        resource directory strings
472        resource data entries
473        actual resource data
474 
475      We build these different types of data in different lists.  */
476 
477   cwi.abfd = abfd;
478   cwi.big_endian = bfd_big_endian (abfd);
479   cwi.sympp = sec->symbol_ptr_ptr;
480   cwi.dirsize = 0;
481   cwi.dirstrsize = 0;
482   cwi.dataentsize = 0;
483   cwi.dirs.d = NULL;
484   cwi.dirs.last = NULL;
485   cwi.dirs.length = 0;
486   cwi.dirstrs.d = NULL;
487   cwi.dirstrs.last = NULL;
488   cwi.dirstrs.length = 0;
489   cwi.dataents.d = NULL;
490   cwi.dataents.last = NULL;
491   cwi.dataents.length = 0;
492   cwi.resources.d = NULL;
493   cwi.resources.last = NULL;
494   cwi.resources.length = 0;
495   cwi.relocs = NULL;
496   cwi.reloc_count = 0;
497 
498   /* Work out the sizes of the resource directory entries, so that we
499      know the various offsets we will need.  */
500   coff_bin_sizes (resources, &cwi);
501 
502   /* Force the directory strings to be 32 bit aligned.  Every other
503      structure is 32 bit aligned anyhow.  */
504   cwi.dirstrsize = (cwi.dirstrsize + 3) &~ 3;
505 
506   /* Actually convert the resources to binary.  */
507   coff_to_bin (resources, &cwi);
508 
509   /* Add another 2 bytes to the directory strings if needed for
510      alignment.  */
511   if ((cwi.dirstrs.length & 3) != 0)
512     {
513       unsigned char *ex;
514 
515       ex = coff_alloc (&cwi.dirstrs, 2);
516       ex[0] = 0;
517       ex[1] = 0;
518     }
519 
520   /* Make sure that the data we built came out to the same size as we
521      calculated initially.  */
522   assert (cwi.dirs.length == cwi.dirsize);
523   assert (cwi.dirstrs.length == cwi.dirstrsize);
524   assert (cwi.dataents.length == cwi.dataentsize);
525 
526   length = (cwi.dirsize
527 	    + cwi.dirstrsize
528 	    + cwi.dataentsize
529 	    + cwi.resources.length);
530 
531   if (! bfd_set_section_size (abfd, sec, length))
532     bfd_fatal ("bfd_set_section_size");
533 
534   bfd_set_reloc (abfd, sec, cwi.relocs, cwi.reloc_count);
535 
536   offset = 0;
537   for (d = cwi.dirs.d; d != NULL; d = d->next)
538     {
539       if (! bfd_set_section_contents (abfd, sec, d->data, offset, d->length))
540 	bfd_fatal ("bfd_set_section_contents");
541       offset += d->length;
542     }
543   for (d = cwi.dirstrs.d; d != NULL; d = d->next)
544     {
545       if (! bfd_set_section_contents (abfd, sec, d->data, offset, d->length))
546 	bfd_fatal ("bfd_set_section_contents");
547       offset += d->length;
548     }
549   for (d = cwi.dataents.d; d != NULL; d = d->next)
550     {
551       if (! bfd_set_section_contents (abfd, sec, d->data, offset, d->length))
552 	bfd_fatal ("bfd_set_section_contents");
553       offset += d->length;
554     }
555   for (d = cwi.resources.d; d != NULL; d = d->next)
556     {
557       if (! bfd_set_section_contents (abfd, sec, d->data, offset, d->length))
558 	bfd_fatal ("bfd_set_section_contents");
559       offset += d->length;
560     }
561 
562   assert (offset == length);
563 
564   if (! bfd_close (abfd))
565     bfd_fatal ("bfd_close");
566 
567   /* We allocated the relocs array using malloc.  */
568   free (cwi.relocs);
569 }
570 
571 /* Work out the sizes of the various fixed size resource directory
572    entries.  This updates fields in CWI.  */
573 
574 static void
575 coff_bin_sizes (const struct res_directory *resdir,
576 		struct coff_write_info *cwi)
577 {
578   const struct res_entry *re;
579 
580   cwi->dirsize += sizeof (struct extern_res_directory);
581 
582   for (re = resdir->entries; re != NULL; re = re->next)
583     {
584       cwi->dirsize += sizeof (struct extern_res_entry);
585 
586       if (re->id.named)
587 	cwi->dirstrsize += re->id.u.n.length * 2 + 2;
588 
589       if (re->subdir)
590 	coff_bin_sizes (re->u.dir, cwi);
591       else
592 	cwi->dataentsize += sizeof (struct extern_res_data);
593     }
594 }
595 
596 /* Allocate data for a particular list.  */
597 
598 static unsigned char *
599 coff_alloc (struct bindata_build *bb, size_t size)
600 {
601   struct bindata *d;
602 
603   d = (struct bindata *) reswr_alloc (sizeof *d);
604 
605   d->next = NULL;
606   d->data = (unsigned char *) reswr_alloc (size);
607   d->length = size;
608 
609   if (bb->d == NULL)
610     bb->d = d;
611   else
612     bb->last->next = d;
613   bb->last = d;
614   bb->length += size;
615 
616   return d->data;
617 }
618 
619 /* Convert the resource directory RESDIR to binary.  */
620 
621 static void
622 coff_to_bin (const struct res_directory *resdir, struct coff_write_info *cwi)
623 {
624   struct extern_res_directory *erd;
625   int ci, cn;
626   const struct res_entry *e;
627   struct extern_res_entry *ere;
628 
629   /* Write out the directory table.  */
630 
631   erd = ((struct extern_res_directory *)
632 	 coff_alloc (&cwi->dirs, sizeof (*erd)));
633 
634   putcwi_32 (cwi, resdir->characteristics, erd->characteristics);
635   putcwi_32 (cwi, resdir->time, erd->time);
636   putcwi_16 (cwi, resdir->major, erd->major);
637   putcwi_16 (cwi, resdir->minor, erd->minor);
638 
639   ci = 0;
640   cn = 0;
641   for (e = resdir->entries; e != NULL; e = e->next)
642     {
643       if (e->id.named)
644 	++cn;
645       else
646 	++ci;
647     }
648 
649   putcwi_16 (cwi, cn, erd->name_count);
650   putcwi_16 (cwi, ci, erd->id_count);
651 
652   /* Write out the data entries.  Note that we allocate space for all
653      the entries before writing them out.  That permits a recursive
654      call to work correctly when writing out subdirectories.  */
655 
656   ere = ((struct extern_res_entry *)
657 	 coff_alloc (&cwi->dirs, (ci + cn) * sizeof (*ere)));
658   for (e = resdir->entries; e != NULL; e = e->next, ere++)
659     {
660       if (! e->id.named)
661 	putcwi_32 (cwi, e->id.u.id, ere->name);
662       else
663 	{
664 	  unsigned char *str;
665 	  int i;
666 
667 	  /* For some reason existing files seem to have the high bit
668              set on the address of the name, although that is not
669              documented.  */
670 	  putcwi_32 (cwi,
671 		     0x80000000 | (cwi->dirsize + cwi->dirstrs.length),
672 		     ere->name);
673 
674 	  str = coff_alloc (&cwi->dirstrs, e->id.u.n.length * 2 + 2);
675 	  putcwi_16 (cwi, e->id.u.n.length, str);
676 	  for (i = 0; i < e->id.u.n.length; i++)
677 	    putcwi_16 (cwi, e->id.u.n.name[i], str + i * 2 + 2);
678 	}
679 
680       if (e->subdir)
681 	{
682 	  putcwi_32 (cwi, 0x80000000 | cwi->dirs.length, ere->rva);
683 	  coff_to_bin (e->u.dir, cwi);
684 	}
685       else
686 	{
687 	  putcwi_32 (cwi,
688 		     cwi->dirsize + cwi->dirstrsize + cwi->dataents.length,
689 		     ere->rva);
690 
691 	  coff_res_to_bin (e->u.res, cwi);
692 	}
693     }
694 }
695 
696 /* Convert the resource RES to binary.  */
697 
698 static void
699 coff_res_to_bin (const struct res_resource *res, struct coff_write_info *cwi)
700 {
701   arelent *r;
702   struct extern_res_data *erd;
703   struct bindata *d;
704   unsigned long length;
705 
706   /* For some reason, although every other address is a section
707      offset, the address of the resource data itself is an RVA.  That
708      means that we need to generate a relocation for it.  We allocate
709      the relocs array using malloc so that we can use realloc.  FIXME:
710      This relocation handling is correct for the i386, but probably
711      not for any other target.  */
712 
713   r = (arelent *) reswr_alloc (sizeof (arelent));
714   r->sym_ptr_ptr = cwi->sympp;
715   r->address = cwi->dirsize + cwi->dirstrsize + cwi->dataents.length;
716   r->addend = 0;
717   r->howto = bfd_reloc_type_lookup (cwi->abfd, BFD_RELOC_RVA);
718   if (r->howto == NULL)
719     bfd_fatal (_("can't get BFD_RELOC_RVA relocation type"));
720 
721   cwi->relocs = xrealloc (cwi->relocs,
722 			  (cwi->reloc_count + 2) * sizeof (arelent *));
723   cwi->relocs[cwi->reloc_count] = r;
724   cwi->relocs[cwi->reloc_count + 1] = NULL;
725   ++cwi->reloc_count;
726 
727   erd = (struct extern_res_data *) coff_alloc (&cwi->dataents, sizeof (*erd));
728 
729   putcwi_32 (cwi,
730 	     (cwi->dirsize
731 	      + cwi->dirstrsize
732 	      + cwi->dataentsize
733 	      + cwi->resources.length),
734 	     erd->rva);
735   putcwi_32 (cwi, res->coff_info.codepage, erd->codepage);
736   putcwi_32 (cwi, res->coff_info.reserved, erd->reserved);
737 
738   d = res_to_bin (res, cwi->big_endian);
739 
740   if (cwi->resources.d == NULL)
741     cwi->resources.d = d;
742   else
743     cwi->resources.last->next = d;
744 
745   length = 0;
746   for (; d->next != NULL; d = d->next)
747     length += d->length;
748   length += d->length;
749   cwi->resources.last = d;
750   cwi->resources.length += length;
751 
752   putcwi_32 (cwi, length, erd->size);
753 
754   /* Force the next resource to have 32 bit alignment.  */
755 
756   if ((length & 3) != 0)
757     {
758       int add;
759       unsigned char *ex;
760 
761       add = 4 - (length & 3);
762 
763       ex = coff_alloc (&cwi->resources, add);
764       memset (ex, 0, add);
765     }
766 }
767