1 /* Generic BFD support for file formats.
2 Copyright (C) 1990, 91, 92, 93, 94, 95, 1999 Free Software Foundation, Inc.
3 Written by Cygnus Support.
5 This file is part of BFD, the Binary File Descriptor library.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
25 A format is a BFD concept of high level file contents type. The
26 formats supported by BFD are:
30 The BFD may contain data, symbols, relocations and debug info.
34 The BFD contains other BFDs and an optional index.
38 The BFD contains the result of an executable core dump.
47 /* IMPORT from targets.c. */
48 extern const size_t _bfd_target_vector_entries;
55 boolean bfd_check_format(bfd *abfd, bfd_format format);
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
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.
89 bfd_check_format (abfd, format)
93 return bfd_check_format_matches (abfd, format, NULL);
98 bfd_check_format_matches
101 boolean bfd_check_format_matches(bfd *abfd, bfd_format format, char ***matching);
104 Like <<bfd_check_format>>, except when it returns false with
105 <<bfd_errno>> set to <<bfd_error_file_ambiguously_recognized>>. In that
106 case, if @var{matching} is not NULL, it will be filled in with
107 a NULL-terminated list of the names of the formats that matched,
108 allocated with <<malloc>>.
109 Then the user may choose a format and try again.
111 When done with the list that @var{matching} points to, the caller
116 bfd_check_format_matches (abfd, format, matching)
121 const bfd_target * const *target, *save_targ, *right_targ;
122 char **matching_vector = NULL;
125 if (!bfd_read_p (abfd) ||
126 ((int)(abfd->format) < (int)bfd_unknown) ||
127 ((int)(abfd->format) >= (int)bfd_type_end)) {
128 bfd_set_error (bfd_error_invalid_operation);
132 if (abfd->format != bfd_unknown)
133 return (abfd->format == format)? true: false;
136 /* Since the target type was defaulted, check them
137 all in the hope that one will be uniquely recognized. */
139 save_targ = abfd->xvec;
144 (char **) bfd_malloc (sizeof (char *) *
145 (_bfd_target_vector_entries + 1));
146 if (!matching_vector)
148 matching_vector[0] = NULL;
149 *matching = matching_vector;
154 /* presume the answer is yes */
155 abfd->format = format;
157 /* If the target type was explicitly specified, just check that target. */
159 if (!abfd->target_defaulted) {
160 if (bfd_seek (abfd, (file_ptr)0, SEEK_SET) != 0) /* rewind! */
162 right_targ = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
164 abfd->xvec = right_targ; /* Set the target as returned */
166 free (matching_vector);
167 return true; /* File position has moved, BTW */
170 /* For a long time the code has dropped through to check all
171 targets if the specified target was wrong. I don't know why,
172 and I'm reluctant to change it. However, in the case of an
173 archive, it can cause problems. If the specified target does
174 not permit archives (e.g., the binary target), then we should
175 not allow some other target to recognize it as an archive, but
176 should instead allow the specified target to recognize it as an
179 if (format == bfd_archive)
181 abfd->xvec = save_targ;
182 abfd->format = bfd_unknown;
184 free (matching_vector);
185 bfd_set_error (bfd_error_file_not_recognized);
190 for (target = bfd_target_vector; *target != NULL; target++) {
191 extern const bfd_target binary_vec;
192 const bfd_target *temp;
194 if (*target == &binary_vec)
197 abfd->xvec = *target; /* Change BFD's target temporarily */
198 if (bfd_seek (abfd, (file_ptr)0, SEEK_SET) != 0)
200 /* If _bfd_check_format neglects to set bfd_error, assume bfd_error_wrong_format.
201 We didn't used to even pay any attention to bfd_error, so I suspect
202 that some _bfd_check_format might have this problem. */
203 bfd_set_error (bfd_error_wrong_format);
204 temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
205 if (temp) { /* This format checks out as ok! */
209 matching_vector[match_count] = temp->name;
210 matching_vector[match_count + 1] = NULL;
213 /* If this is the default target, accept it, even if other targets
214 might match. People who want those other targets have to set
215 the GNUTARGET variable. */
216 if (temp == bfd_default_vector[0])
220 matching_vector[0] = temp->name;
221 matching_vector[1] = NULL;
227 /* Big- and little-endian b.out archives look the same, but it doesn't
228 * matter: there is no difference in their headers, and member file byte
229 * orders will (I hope) be handled appropriately by bfd. Ditto for big
230 * and little coff archives. And the 4 coff/b.out object formats are
231 * unambiguous. So accept the first match we find.
235 } else if (bfd_get_error () != bfd_error_wrong_format) {
236 abfd->xvec = save_targ;
237 abfd->format = bfd_unknown;
238 if (matching && bfd_get_error () != bfd_error_file_ambiguously_recognized)
239 free (matching_vector);
244 if (match_count == 1) {
245 abfd->xvec = right_targ; /* Change BFD's target permanently */
247 free (matching_vector);
248 return true; /* File position has moved, BTW */
251 abfd->xvec = save_targ; /* Restore original target type */
252 abfd->format = bfd_unknown; /* Restore original format */
253 if (match_count == 0)
255 bfd_set_error (bfd_error_file_not_recognized);
257 free (matching_vector);
260 bfd_set_error (bfd_error_file_ambiguously_recognized);
269 boolean bfd_set_format(bfd *abfd, bfd_format format);
272 This function sets the file format of the BFD @var{abfd} to the
273 format @var{format}. If the target set in the BFD does not
274 support the format requested, the format is invalid, or the BFD
275 is not open for writing, then an error occurs.
280 bfd_set_format (abfd, format)
285 if (bfd_read_p (abfd) ||
286 ((int)abfd->format < (int)bfd_unknown) ||
287 ((int)abfd->format >= (int)bfd_type_end)) {
288 bfd_set_error (bfd_error_invalid_operation);
292 if (abfd->format != bfd_unknown)
293 return (abfd->format == format) ? true:false;
295 /* presume the answer is yes */
296 abfd->format = format;
298 if (!BFD_SEND_FMT (abfd, _bfd_set_format, (abfd))) {
299 abfd->format = bfd_unknown;
312 CONST char *bfd_format_string(bfd_format format);
315 Return a pointer to a const string
316 <<invalid>>, <<object>>, <<archive>>, <<core>>, or <<unknown>>,
317 depending upon the value of @var{format}.
321 bfd_format_string (format)
324 if (((int)format <(int) bfd_unknown)
325 || ((int)format >=(int) bfd_type_end))
330 return "object"; /* linker/assember/compiler output */
332 return "archive"; /* object archive file */
334 return "core"; /* core dump */