Add support for generating DWARF2 debug sections in the x86 PE port
[binutils.git] / bfd / format.c
blob9d9ee86bac40939eb8f316570cdacdc7f26d02a6
1 /* Generic BFD support for file formats.
2 Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1999, 2000, 2001, 2002, 2003
3 Free Software Foundation, Inc.
4 Written by Cygnus Support.
6 This file is part of BFD, the Binary File Descriptor library.
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
11 (at your option) any later version.
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.
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 02111-1307, USA. */
23 SECTION
24 File formats
26 A format is a BFD concept of high level file contents type. The
27 formats supported by BFD are:
29 o <<bfd_object>>
31 The BFD may contain data, symbols, relocations and debug info.
33 o <<bfd_archive>>
35 The BFD contains other BFDs and an optional index.
37 o <<bfd_core>>
39 The BFD contains the result of an executable core dump.
43 #include "bfd.h"
44 #include "sysdep.h"
45 #include "libbfd.h"
47 /* IMPORT from targets.c. */
48 extern const size_t _bfd_target_vector_entries;
51 FUNCTION
52 bfd_check_format
54 SYNOPSIS
55 bfd_boolean bfd_check_format (bfd *abfd, bfd_format format);
57 DESCRIPTION
58 Verify if the file attached to the BFD @var{abfd} is compatible
59 with the format @var{format} (i.e., one of <<bfd_object>>,
60 <<bfd_archive>> or <<bfd_core>>).
62 If the BFD has been set to a specific target before the
63 call, only the named target and format combination is
64 checked. If the target has not been set, or has been set to
65 <<default>>, then all the known target backends is
66 interrogated to determine a match. If the default target
67 matches, it is used. If not, exactly one target must recognize
68 the file, or an error results.
70 The function returns <<TRUE>> on success, otherwise <<FALSE>>
71 with one of the following error codes:
73 o <<bfd_error_invalid_operation>> -
74 if <<format>> is not one of <<bfd_object>>, <<bfd_archive>> or
75 <<bfd_core>>.
77 o <<bfd_error_system_call>> -
78 if an error occured during a read - even some file mismatches
79 can cause bfd_error_system_calls.
81 o <<file_not_recognised>> -
82 none of the backends recognised the file format.
84 o <<bfd_error_file_ambiguously_recognized>> -
85 more than one backend recognised the file format.
88 bfd_boolean
89 bfd_check_format (bfd *abfd, bfd_format format)
91 return bfd_check_format_matches (abfd, format, NULL);
95 FUNCTION
96 bfd_check_format_matches
98 SYNOPSIS
99 bfd_boolean bfd_check_format_matches
100 (bfd *abfd, bfd_format format, char ***matching);
102 DESCRIPTION
103 Like <<bfd_check_format>>, except when it returns FALSE with
104 <<bfd_errno>> set to <<bfd_error_file_ambiguously_recognized>>. In that
105 case, if @var{matching} is not NULL, it will be filled in with
106 a NULL-terminated list of the names of the formats that matched,
107 allocated with <<malloc>>.
108 Then the user may choose a format and try again.
110 When done with the list that @var{matching} points to, the caller
111 should free it.
114 bfd_boolean
115 bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
117 extern const bfd_target binary_vec;
118 const bfd_target * const *target;
119 const bfd_target **matching_vector = NULL;
120 const bfd_target *save_targ, *right_targ, *ar_right_targ;
121 int match_count;
122 int ar_match_index;
124 if (!bfd_read_p (abfd)
125 || (unsigned int) abfd->format >= (unsigned int) bfd_type_end)
127 bfd_set_error (bfd_error_invalid_operation);
128 return FALSE;
131 if (abfd->format != bfd_unknown)
132 return abfd->format == format;
134 /* Since the target type was defaulted, check them
135 all in the hope that one will be uniquely recognized. */
136 save_targ = abfd->xvec;
137 match_count = 0;
138 ar_match_index = _bfd_target_vector_entries;
140 if (matching)
142 bfd_size_type amt;
144 *matching = NULL;
145 amt = sizeof (*matching_vector) * 2 * _bfd_target_vector_entries;
146 matching_vector = bfd_malloc (amt);
147 if (!matching_vector)
148 return FALSE;
151 right_targ = 0;
152 ar_right_targ = 0;
154 /* Presume the answer is yes. */
155 abfd->format = format;
157 /* If the target type was explicitly specified, just check that target. */
158 if (!abfd->target_defaulted)
160 if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0) /* rewind! */
162 if (matching)
163 free (matching_vector);
164 return FALSE;
167 right_targ = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
169 if (right_targ)
171 abfd->xvec = right_targ; /* Set the target as returned. */
173 if (matching)
174 free (matching_vector);
176 return TRUE; /* File position has moved, BTW. */
179 /* For a long time the code has dropped through to check all
180 targets if the specified target was wrong. I don't know why,
181 and I'm reluctant to change it. However, in the case of an
182 archive, it can cause problems. If the specified target does
183 not permit archives (e.g., the binary target), then we should
184 not allow some other target to recognize it as an archive, but
185 should instead allow the specified target to recognize it as an
186 object. When I first made this change, it broke the PE target,
187 because the specified pei-i386 target did not recognize the
188 actual pe-i386 archive. Since there may be other problems of
189 this sort, I changed this test to check only for the binary
190 target. */
191 if (format == bfd_archive && save_targ == &binary_vec)
193 abfd->xvec = save_targ;
194 abfd->format = bfd_unknown;
196 if (matching)
197 free (matching_vector);
199 bfd_set_error (bfd_error_file_not_recognized);
201 return FALSE;
205 for (target = bfd_target_vector; *target != NULL; target++)
207 const bfd_target *temp;
208 bfd_error_type err;
210 if (*target == &binary_vec)
211 continue;
213 abfd->xvec = *target; /* Change BFD's target temporarily. */
215 if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
217 if (matching)
218 free (matching_vector);
219 return FALSE;
222 /* If _bfd_check_format neglects to set bfd_error, assume
223 bfd_error_wrong_format. We didn't used to even pay any
224 attention to bfd_error, so I suspect that some
225 _bfd_check_format might have this problem. */
226 bfd_set_error (bfd_error_wrong_format);
228 temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
230 if (temp)
232 /* This format checks out as ok! */
233 right_targ = temp;
235 /* If this is the default target, accept it, even if other
236 targets might match. People who want those other targets
237 have to set the GNUTARGET variable. */
238 if (temp == bfd_default_vector[0])
240 match_count = 1;
241 break;
244 if (matching)
245 matching_vector[match_count] = temp;
247 match_count++;
249 #ifdef GNU960
250 /* Big- and little-endian b.out archives look the same, but it
251 doesn't matter: there is no difference in their headers, and
252 member file byte orders will (I hope) be handled appropriately
253 by bfd. Ditto for big and little coff archives. And the 4
254 coff/b.out object formats are unambiguous. So accept the
255 first match we find. */
256 break;
257 #endif
259 else if ((err = bfd_get_error ()) == bfd_error_wrong_object_format
260 || err == bfd_error_file_ambiguously_recognized)
262 /* An archive with objects of the wrong type, or an
263 ambiguous match. We want this target to match if we get
264 no better matches. */
265 if (ar_right_targ != bfd_default_vector[0])
266 ar_right_targ = *target;
267 if (matching)
268 matching_vector[ar_match_index] = *target;
269 ar_match_index++;
271 else if (err != bfd_error_wrong_format)
273 abfd->xvec = save_targ;
274 abfd->format = bfd_unknown;
276 if (matching)
277 free (matching_vector);
279 return FALSE;
283 if (match_count == 0)
285 /* Try partial matches. */
286 right_targ = ar_right_targ;
288 if (right_targ == bfd_default_vector[0])
290 match_count = 1;
292 else
294 match_count = ar_match_index - _bfd_target_vector_entries;
296 if (matching && match_count > 1)
297 memcpy (matching_vector,
298 matching_vector + _bfd_target_vector_entries,
299 sizeof (*matching_vector) * match_count);
303 if (match_count > 1
304 && bfd_associated_vector != NULL
305 && matching)
307 const bfd_target * const *assoc = bfd_associated_vector;
309 while ((right_targ = *assoc++) != NULL)
311 int i = match_count;
313 while (--i >= 0)
314 if (matching_vector[i] == right_targ)
315 break;
317 if (i >= 0)
319 match_count = 1;
320 break;
325 if (match_count == 1)
327 abfd->xvec = right_targ; /* Change BFD's target permanently. */
329 if (matching)
330 free (matching_vector);
332 return TRUE; /* File position has moved, BTW. */
335 abfd->xvec = save_targ; /* Restore original target type. */
336 abfd->format = bfd_unknown; /* Restore original format. */
338 if (match_count == 0)
340 bfd_set_error (bfd_error_file_not_recognized);
342 if (matching)
343 free (matching_vector);
345 else
347 bfd_set_error (bfd_error_file_ambiguously_recognized);
349 if (matching)
351 *matching = (char **) matching_vector;
352 matching_vector[match_count] = NULL;
353 /* Return target names. This is a little nasty. Maybe we
354 should do another bfd_malloc? */
355 while (--match_count >= 0)
357 const char *name = matching_vector[match_count]->name;
358 *(const char **) &matching_vector[match_count] = name;
363 return FALSE;
367 FUNCTION
368 bfd_set_format
370 SYNOPSIS
371 bfd_boolean bfd_set_format (bfd *abfd, bfd_format format);
373 DESCRIPTION
374 This function sets the file format of the BFD @var{abfd} to the
375 format @var{format}. If the target set in the BFD does not
376 support the format requested, the format is invalid, or the BFD
377 is not open for writing, then an error occurs.
380 bfd_boolean
381 bfd_set_format (bfd *abfd, bfd_format format)
383 if (bfd_read_p (abfd)
384 || (unsigned int) abfd->format >= (unsigned int) bfd_type_end)
386 bfd_set_error (bfd_error_invalid_operation);
387 return FALSE;
390 if (abfd->format != bfd_unknown)
391 return abfd->format == format;
393 /* Presume the answer is yes. */
394 abfd->format = format;
396 if (!BFD_SEND_FMT (abfd, _bfd_set_format, (abfd)))
398 abfd->format = bfd_unknown;
399 return FALSE;
402 return TRUE;
406 FUNCTION
407 bfd_format_string
409 SYNOPSIS
410 const char *bfd_format_string (bfd_format format);
412 DESCRIPTION
413 Return a pointer to a const string
414 <<invalid>>, <<object>>, <<archive>>, <<core>>, or <<unknown>>,
415 depending upon the value of @var{format}.
418 const char *
419 bfd_format_string (bfd_format format)
421 if (((int) format < (int) bfd_unknown)
422 || ((int) format >= (int) bfd_type_end))
423 return "invalid";
425 switch (format)
427 case bfd_object:
428 return "object"; /* Linker/assembler/compiler output. */
429 case bfd_archive:
430 return "archive"; /* Object archive file. */
431 case bfd_core:
432 return "core"; /* Core dump. */
433 default:
434 return "unknown";