1 /* Plugin support for BFD.
2    Copyright (C) 2009-2014 Free Software Foundation, Inc.
3 
4    This file is part of BFD, the Binary File Descriptor library.
5 
6    This program is free software; you can redistribute it and/or modify
7    it under the terms of the GNU General Public License as published by
8    the Free Software Foundation; either version 3 of the License, or
9    (at your option) any later version.
10 
11    This program is distributed in the hope that it will be useful,
12    but WITHOUT ANY WARRANTY; without even the implied warranty of
13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14    GNU General Public License for more details.
15 
16    You should have received a copy of the GNU General Public License
17    along with this program; if not, write to the Free Software
18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
19    MA 02110-1301, USA.  */
20 
21 #include "sysdep.h"
22 #include "bfd.h"
23 
24 #if BFD_SUPPORTS_PLUGINS
25 
26 #include <assert.h>
27 #ifdef HAVE_DLFCN_H
28 #include <dlfcn.h>
29 #elif defined (HAVE_WINDOWS_H)
30 #include <windows.h>
31 #else
32 #error Unknown how to handle dynamic-load-libraries.
33 #endif
34 #include <stdarg.h>
35 #include "plugin-api.h"
36 #include "plugin.h"
37 #include "libbfd.h"
38 #include "libiberty.h"
39 #include <dirent.h>
40 
41 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
42 
43 #define RTLD_NOW 0      /* Dummy value.  */
44 
45 static void *
dlopen(const char * file,int mode ATTRIBUTE_UNUSED)46 dlopen (const char *file, int mode ATTRIBUTE_UNUSED)
47 {
48   return LoadLibrary (file);
49 }
50 
51 static void *
dlsym(void * handle,const char * name)52 dlsym (void *handle, const char *name)
53 {
54   return GetProcAddress (handle, name);
55 }
56 
57 static int ATTRIBUTE_UNUSED
dlclose(void * handle)58 dlclose (void *handle)
59 {
60   FreeLibrary (handle);
61   return 0;
62 }
63 
64 static const char *
dlerror(void)65 dlerror (void)
66 {
67   return "Unable to load DLL.";
68 }
69 
70 #endif /* !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)  */
71 
72 #define bfd_plugin_close_and_cleanup                  _bfd_generic_close_and_cleanup
73 #define bfd_plugin_bfd_free_cached_info               _bfd_generic_bfd_free_cached_info
74 #define bfd_plugin_new_section_hook                   _bfd_generic_new_section_hook
75 #define bfd_plugin_get_section_contents               _bfd_generic_get_section_contents
76 #define bfd_plugin_get_section_contents_in_window     _bfd_generic_get_section_contents_in_window
77 #define bfd_plugin_bfd_copy_private_header_data       _bfd_generic_bfd_copy_private_header_data
78 #define bfd_plugin_bfd_merge_private_bfd_data         _bfd_generic_bfd_merge_private_bfd_data
79 #define bfd_plugin_bfd_copy_private_header_data       _bfd_generic_bfd_copy_private_header_data
80 #define bfd_plugin_bfd_set_private_flags              _bfd_generic_bfd_set_private_flags
81 #define bfd_plugin_core_file_matches_executable_p     generic_core_file_matches_executable_p
82 #define bfd_plugin_bfd_is_local_label_name            _bfd_nosymbols_bfd_is_local_label_name
83 #define bfd_plugin_bfd_is_target_special_symbol       ((bfd_boolean (*) (bfd *, asymbol *)) bfd_false)
84 #define bfd_plugin_get_lineno                         _bfd_nosymbols_get_lineno
85 #define bfd_plugin_find_nearest_line                  _bfd_nosymbols_find_nearest_line
86 #define bfd_plugin_find_line                          _bfd_nosymbols_find_line
87 #define bfd_plugin_find_inliner_info                  _bfd_nosymbols_find_inliner_info
88 #define bfd_plugin_bfd_make_debug_symbol              _bfd_nosymbols_bfd_make_debug_symbol
89 #define bfd_plugin_read_minisymbols                   _bfd_generic_read_minisymbols
90 #define bfd_plugin_minisymbol_to_symbol               _bfd_generic_minisymbol_to_symbol
91 #define bfd_plugin_set_arch_mach                      bfd_default_set_arch_mach
92 #define bfd_plugin_set_section_contents               _bfd_generic_set_section_contents
93 #define bfd_plugin_bfd_get_relocated_section_contents bfd_generic_get_relocated_section_contents
94 #define bfd_plugin_bfd_relax_section                  bfd_generic_relax_section
95 #define bfd_plugin_bfd_link_hash_table_create         _bfd_generic_link_hash_table_create
96 #define bfd_plugin_bfd_link_add_symbols               _bfd_generic_link_add_symbols
97 #define bfd_plugin_bfd_link_just_syms                 _bfd_generic_link_just_syms
98 #define bfd_plugin_bfd_final_link                     _bfd_generic_final_link
99 #define bfd_plugin_bfd_link_split_section             _bfd_generic_link_split_section
100 #define bfd_plugin_bfd_gc_sections                    bfd_generic_gc_sections
101 #define bfd_plugin_bfd_lookup_section_flags           bfd_generic_lookup_section_flags
102 #define bfd_plugin_bfd_merge_sections                 bfd_generic_merge_sections
103 #define bfd_plugin_bfd_is_group_section               bfd_generic_is_group_section
104 #define bfd_plugin_bfd_discard_group                  bfd_generic_discard_group
105 #define bfd_plugin_section_already_linked             _bfd_generic_section_already_linked
106 #define bfd_plugin_bfd_define_common_symbol           bfd_generic_define_common_symbol
107 #define bfd_plugin_bfd_copy_link_hash_symbol_type     _bfd_generic_copy_link_hash_symbol_type
108 
109 static enum ld_plugin_status
message(int level ATTRIBUTE_UNUSED,const char * format,...)110 message (int level ATTRIBUTE_UNUSED,
111 	 const char * format, ...)
112 {
113   va_list args;
114   va_start (args, format);
115   printf ("bfd plugin: ");
116   vprintf (format, args);
117   putchar ('\n');
118   va_end (args);
119   return LDPS_OK;
120 }
121 
122 /* Register a claim-file handler. */
123 static ld_plugin_claim_file_handler claim_file;
124 
125 static enum ld_plugin_status
register_claim_file(ld_plugin_claim_file_handler handler)126 register_claim_file (ld_plugin_claim_file_handler handler)
127 {
128   claim_file = handler;
129   return LDPS_OK;
130 }
131 
132 static enum ld_plugin_status
add_symbols(void * handle,int nsyms,const struct ld_plugin_symbol * syms)133 add_symbols (void * handle,
134 	     int nsyms,
135 	     const struct ld_plugin_symbol * syms)
136 {
137   bfd *abfd = handle;
138   struct plugin_data_struct *plugin_data =
139     bfd_alloc (abfd, sizeof (plugin_data_struct));
140 
141   plugin_data->nsyms = nsyms;
142   plugin_data->syms = syms;
143 
144   if (nsyms != 0)
145     abfd->flags |= HAS_SYMS;
146 
147   abfd->tdata.plugin_data = plugin_data;
148   return LDPS_OK;
149 }
150 
151 static const char *plugin_program_name;
152 
153 void
bfd_plugin_set_program_name(const char * program_name)154 bfd_plugin_set_program_name (const char *program_name)
155 {
156   plugin_program_name = program_name;
157 }
158 
159 static int
try_claim(bfd * abfd)160 try_claim (bfd *abfd)
161 {
162   int claimed = 0;
163   struct ld_plugin_input_file file;
164   bfd *iobfd;
165 
166   file.name = abfd->filename;
167 
168   if (abfd->my_archive)
169     {
170       iobfd = abfd->my_archive;
171       file.offset = abfd->origin;
172       file.filesize = arelt_size (abfd);
173     }
174   else
175     {
176       iobfd = abfd;
177       file.offset = 0;
178       file.filesize = 0;
179     }
180 
181   if (!iobfd->iostream && !bfd_open_file (iobfd))
182     return 0;
183 
184   file.fd = fileno ((FILE *) iobfd->iostream);
185 
186   if (!abfd->my_archive)
187     {
188       struct stat stat_buf;
189       if (fstat (file.fd, &stat_buf))
190         return 0;
191       file.filesize = stat_buf.st_size;
192     }
193 
194   file.handle = abfd;
195   off_t cur_offset = lseek(file.fd, 0, SEEK_CUR);
196   claim_file (&file, &claimed);
197   lseek(file.fd, cur_offset, SEEK_SET);
198   if (!claimed)
199     return 0;
200 
201   return 1;
202 }
203 
204 static int
try_load_plugin(const char * pname,bfd * abfd)205 try_load_plugin (const char *pname, bfd *abfd)
206 {
207   void *plugin_handle;
208   int tv_size = 4;
209   struct ld_plugin_tv tv[tv_size];
210   int i;
211   ld_plugin_onload onload;
212   enum ld_plugin_status status;
213 
214   plugin_handle = dlopen (pname, RTLD_NOW);
215   if (!plugin_handle)
216     {
217       (*_bfd_error_handler)("%s\n", dlerror ());
218       return 0;
219     }
220 
221   onload = dlsym (plugin_handle, "onload");
222   if (!onload)
223     goto err;
224 
225   i = 0;
226   tv[i].tv_tag = LDPT_MESSAGE;
227   tv[i].tv_u.tv_message = message;
228 
229   ++i;
230   tv[i].tv_tag = LDPT_REGISTER_CLAIM_FILE_HOOK;
231   tv[i].tv_u.tv_register_claim_file = register_claim_file;
232 
233   ++i;
234   tv[i].tv_tag = LDPT_ADD_SYMBOLS;
235   tv[i].tv_u.tv_add_symbols = add_symbols;
236 
237   ++i;
238   tv[i].tv_tag = LDPT_NULL;
239   tv[i].tv_u.tv_val = 0;
240 
241   status = (*onload)(tv);
242 
243   if (status != LDPS_OK)
244     goto err;
245 
246   if (!claim_file)
247     goto err;
248 
249   if (!try_claim (abfd))
250     goto err;
251 
252   return 1;
253 
254  err:
255   plugin_handle = NULL;
256   return 0;
257 }
258 
259 static const char *plugin_name;
260 
261 void
bfd_plugin_set_plugin(const char * p)262 bfd_plugin_set_plugin (const char *p)
263 {
264   plugin_name = p;
265 }
266 
267 static int
load_plugin(bfd * abfd)268 load_plugin (bfd *abfd)
269 {
270   char *plugin_dir;
271   char *p;
272   DIR *d;
273   struct dirent *ent;
274   int found = 0;
275 
276   if (plugin_name)
277     return try_load_plugin (plugin_name, abfd);
278 
279   if (plugin_program_name == NULL)
280     return 0;
281 
282   plugin_dir = concat (BINDIR, "/../lib/bfd-plugins", NULL);
283   p = make_relative_prefix (plugin_program_name,
284 			    BINDIR,
285 			    plugin_dir);
286   free (plugin_dir);
287   plugin_dir = NULL;
288 
289   d = opendir (p);
290   if (!d)
291     goto out;
292 
293   while ((ent = readdir (d)))
294     {
295       char *full_name;
296       struct stat s;
297 
298       full_name = concat (p, "/", ent->d_name, NULL);
299       if (stat(full_name, &s) == 0 && S_ISREG (s.st_mode))
300 	found = try_load_plugin (full_name, abfd);
301       free (full_name);
302       if (found)
303 	break;
304     }
305 
306  out:
307   free (p);
308   if (d)
309     closedir (d);
310 
311   return found;
312 }
313 
314 
315 static const bfd_target *
bfd_plugin_object_p(bfd * abfd)316 bfd_plugin_object_p (bfd *abfd)
317 {
318   if (!load_plugin (abfd))
319     return NULL;
320 
321   return abfd->xvec;
322 }
323 
324 /* Copy any private info we understand from the input bfd
325    to the output bfd.  */
326 
327 static bfd_boolean
bfd_plugin_bfd_copy_private_bfd_data(bfd * ibfd ATTRIBUTE_UNUSED,bfd * obfd ATTRIBUTE_UNUSED)328 bfd_plugin_bfd_copy_private_bfd_data (bfd *ibfd ATTRIBUTE_UNUSED,
329 				      bfd *obfd ATTRIBUTE_UNUSED)
330 {
331   BFD_ASSERT (0);
332   return TRUE;
333 }
334 
335 /* Copy any private info we understand from the input section
336    to the output section.  */
337 
338 static bfd_boolean
bfd_plugin_bfd_copy_private_section_data(bfd * ibfd ATTRIBUTE_UNUSED,asection * isection ATTRIBUTE_UNUSED,bfd * obfd ATTRIBUTE_UNUSED,asection * osection ATTRIBUTE_UNUSED)339 bfd_plugin_bfd_copy_private_section_data (bfd *ibfd ATTRIBUTE_UNUSED,
340 					  asection *isection ATTRIBUTE_UNUSED,
341 					  bfd *obfd ATTRIBUTE_UNUSED,
342 					  asection *osection ATTRIBUTE_UNUSED)
343 {
344   BFD_ASSERT (0);
345   return TRUE;
346 }
347 
348 /* Copy any private info we understand from the input symbol
349    to the output symbol.  */
350 
351 static bfd_boolean
bfd_plugin_bfd_copy_private_symbol_data(bfd * ibfd ATTRIBUTE_UNUSED,asymbol * isymbol ATTRIBUTE_UNUSED,bfd * obfd ATTRIBUTE_UNUSED,asymbol * osymbol ATTRIBUTE_UNUSED)352 bfd_plugin_bfd_copy_private_symbol_data (bfd *ibfd ATTRIBUTE_UNUSED,
353 					 asymbol *isymbol ATTRIBUTE_UNUSED,
354 					 bfd *obfd ATTRIBUTE_UNUSED,
355 					 asymbol *osymbol ATTRIBUTE_UNUSED)
356 {
357   BFD_ASSERT (0);
358   return TRUE;
359 }
360 
361 static bfd_boolean
bfd_plugin_bfd_print_private_bfd_data(bfd * abfd ATTRIBUTE_UNUSED,PTR ptr ATTRIBUTE_UNUSED)362 bfd_plugin_bfd_print_private_bfd_data (bfd *abfd ATTRIBUTE_UNUSED, PTR ptr ATTRIBUTE_UNUSED)
363 {
364   BFD_ASSERT (0);
365   return TRUE;
366 }
367 
368 static char *
bfd_plugin_core_file_failing_command(bfd * abfd ATTRIBUTE_UNUSED)369 bfd_plugin_core_file_failing_command (bfd *abfd ATTRIBUTE_UNUSED)
370 {
371   BFD_ASSERT (0);
372   return NULL;
373 }
374 
375 static int
bfd_plugin_core_file_failing_signal(bfd * abfd ATTRIBUTE_UNUSED)376 bfd_plugin_core_file_failing_signal (bfd *abfd ATTRIBUTE_UNUSED)
377 {
378   BFD_ASSERT (0);
379   return 0;
380 }
381 
382 static int
bfd_plugin_core_file_pid(bfd * abfd ATTRIBUTE_UNUSED)383 bfd_plugin_core_file_pid (bfd *abfd ATTRIBUTE_UNUSED)
384 {
385   BFD_ASSERT (0);
386   return 0;
387 }
388 
389 static long
bfd_plugin_get_symtab_upper_bound(bfd * abfd)390 bfd_plugin_get_symtab_upper_bound (bfd *abfd)
391 {
392   struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
393   long nsyms = plugin_data->nsyms;
394 
395   BFD_ASSERT (nsyms >= 0);
396 
397   return ((nsyms + 1) * sizeof (asymbol *));
398 }
399 
400 static flagword
convert_flags(const struct ld_plugin_symbol * sym)401 convert_flags (const struct ld_plugin_symbol *sym)
402 {
403  switch (sym->def)
404    {
405    case LDPK_DEF:
406    case LDPK_COMMON:
407    case LDPK_UNDEF:
408      return BSF_GLOBAL;
409 
410    case LDPK_WEAKUNDEF:
411    case LDPK_WEAKDEF:
412      return BSF_GLOBAL | BSF_WEAK;
413 
414    default:
415      BFD_ASSERT (0);
416      return 0;
417    }
418 }
419 
420 static long
bfd_plugin_canonicalize_symtab(bfd * abfd,asymbol ** alocation)421 bfd_plugin_canonicalize_symtab (bfd *abfd,
422 				asymbol **alocation)
423 {
424   struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
425   long nsyms = plugin_data->nsyms;
426   const struct ld_plugin_symbol *syms = plugin_data->syms;
427   static asection fake_section;
428   static asection fake_common_section;
429   int i;
430 
431   fake_section.name = ".text";
432   fake_common_section.flags = SEC_IS_COMMON;
433 
434   for (i = 0; i < nsyms; i++)
435     {
436       asymbol *s = bfd_alloc (abfd, sizeof (asymbol));
437 
438       BFD_ASSERT (s);
439       alocation[i] = s;
440 
441       s->the_bfd = abfd;
442       s->name = syms[i].name;
443       s->value = 0;
444       s->flags = convert_flags (&syms[i]);
445       switch (syms[i].def)
446 	{
447 	case LDPK_COMMON:
448 	  s->section = &fake_common_section;
449 	  break;
450 	case LDPK_UNDEF:
451 	case LDPK_WEAKUNDEF:
452 	  s->section = bfd_und_section_ptr;
453 	  break;
454 	case LDPK_DEF:
455 	case LDPK_WEAKDEF:
456 	  s->section = &fake_section;
457 	  break;
458 	default:
459 	  BFD_ASSERT (0);
460 	}
461 
462       s->udata.p = (void *) &syms[i];
463     }
464 
465   return nsyms;
466 }
467 
468 static void
bfd_plugin_print_symbol(bfd * abfd ATTRIBUTE_UNUSED,PTR afile ATTRIBUTE_UNUSED,asymbol * symbol ATTRIBUTE_UNUSED,bfd_print_symbol_type how ATTRIBUTE_UNUSED)469 bfd_plugin_print_symbol (bfd *abfd ATTRIBUTE_UNUSED,
470 			 PTR afile ATTRIBUTE_UNUSED,
471 			 asymbol *symbol ATTRIBUTE_UNUSED,
472 			 bfd_print_symbol_type how ATTRIBUTE_UNUSED)
473 {
474   BFD_ASSERT (0);
475 }
476 
477 static void
bfd_plugin_get_symbol_info(bfd * abfd ATTRIBUTE_UNUSED,asymbol * symbol,symbol_info * ret)478 bfd_plugin_get_symbol_info (bfd *abfd ATTRIBUTE_UNUSED,
479 			    asymbol *symbol,
480 			    symbol_info *ret)
481 {
482   bfd_symbol_info (symbol, ret);
483 }
484 
485 /* Make an empty symbol. */
486 
487 static asymbol *
bfd_plugin_make_empty_symbol(bfd * abfd)488 bfd_plugin_make_empty_symbol (bfd *abfd)
489 {
490   asymbol *new_symbol = bfd_zalloc (abfd, sizeof (asymbol));
491   if (new_symbol == NULL)
492     return new_symbol;
493   new_symbol->the_bfd = abfd;
494   return new_symbol;
495 }
496 
497 static int
bfd_plugin_sizeof_headers(bfd * a ATTRIBUTE_UNUSED,struct bfd_link_info * info ATTRIBUTE_UNUSED)498 bfd_plugin_sizeof_headers (bfd *a ATTRIBUTE_UNUSED,
499 			   struct bfd_link_info *info ATTRIBUTE_UNUSED)
500 {
501   BFD_ASSERT (0);
502   return 0;
503 }
504 
505 const bfd_target plugin_vec =
506 {
507   "plugin",			/* Name.  */
508   bfd_target_unknown_flavour,
509   BFD_ENDIAN_LITTLE,		/* Target byte order.  */
510   BFD_ENDIAN_LITTLE,		/* Target headers byte order.  */
511   (HAS_RELOC | EXEC_P |		/* Object flags.  */
512    HAS_LINENO | HAS_DEBUG |
513    HAS_SYMS | HAS_LOCALS | DYNAMIC | WP_TEXT | D_PAGED),
514   (SEC_CODE | SEC_DATA | SEC_ROM | SEC_HAS_CONTENTS
515    | SEC_ALLOC | SEC_LOAD | SEC_RELOC),	/* Section flags.  */
516   0,				/* symbol_leading_char.  */
517   '/',				/* ar_pad_char.  */
518   15,				/* ar_max_namelen.  */
519   0,				/* match priority.  */
520 
521   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
522   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
523   bfd_getl16, bfd_getl_signed_16, bfd_putl16,	/* data */
524   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
525   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
526   bfd_getl16, bfd_getl_signed_16, bfd_putl16,	/* hdrs */
527 
528   {				/* bfd_check_format.  */
529     _bfd_dummy_target,
530     bfd_plugin_object_p,
531     bfd_generic_archive_p,
532     _bfd_dummy_target
533   },
534   {				/* bfd_set_format.  */
535     bfd_false,
536     bfd_false,
537     _bfd_generic_mkarchive,
538     bfd_false,
539   },
540   {				/* bfd_write_contents.  */
541     bfd_false,
542     bfd_false,
543     _bfd_write_archive_contents,
544     bfd_false,
545   },
546 
547   BFD_JUMP_TABLE_GENERIC (bfd_plugin),
548   BFD_JUMP_TABLE_COPY (bfd_plugin),
549   BFD_JUMP_TABLE_CORE (bfd_plugin),
550   BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff),
551   BFD_JUMP_TABLE_SYMBOLS (bfd_plugin),
552   BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
553   BFD_JUMP_TABLE_WRITE (bfd_plugin),
554   BFD_JUMP_TABLE_LINK (bfd_plugin),
555   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
556 
557   NULL,
558 
559   NULL  			/* backend_data.  */
560 };
561 #endif /* BFD_SUPPORTS_PLUGIN */
562