| 1 | /* Generic BFD support for file formats. |
| 2 | Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1999, 2000, 2001, 2002, |
| 3 | 2003, 2005, 2007, 2008, 2009 Free Software Foundation, Inc. |
| 4 | Written by Cygnus Support. |
| 5 | |
| 6 | This file is part of BFD, the Binary File Descriptor library. |
| 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 3 of the License, or |
| 11 | (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., 51 Franklin Street - Fifth Floor, Boston, |
| 21 | MA 02110-1301, USA. */ |
| 22 | |
| 23 | |
| 24 | /* |
| 25 | SECTION |
| 26 | File formats |
| 27 | |
| 28 | A format is a BFD concept of high level file contents type. The |
| 29 | formats supported by BFD are: |
| 30 | |
| 31 | o <<bfd_object>> |
| 32 | |
| 33 | The BFD may contain data, symbols, relocations and debug info. |
| 34 | |
| 35 | o <<bfd_archive>> |
| 36 | |
| 37 | The BFD contains other BFDs and an optional index. |
| 38 | |
| 39 | o <<bfd_core>> |
| 40 | |
| 41 | The BFD contains the result of an executable core dump. |
| 42 | |
| 43 | SUBSECTION |
| 44 | File format functions |
| 45 | */ |
| 46 | |
| 47 | #include "sysdep.h" |
| 48 | #include "bfd.h" |
| 49 | #include "libbfd.h" |
| 50 | |
| 51 | /* IMPORT from targets.c. */ |
| 52 | extern const size_t _bfd_target_vector_entries; |
| 53 | |
| 54 | /* |
| 55 | FUNCTION |
| 56 | bfd_check_format |
| 57 | |
| 58 | SYNOPSIS |
| 59 | bfd_boolean bfd_check_format (bfd *abfd, bfd_format format); |
| 60 | |
| 61 | DESCRIPTION |
| 62 | Verify if the file attached to the BFD @var{abfd} is compatible |
| 63 | with the format @var{format} (i.e., one of <<bfd_object>>, |
| 64 | <<bfd_archive>> or <<bfd_core>>). |
| 65 | |
| 66 | If the BFD has been set to a specific target before the |
| 67 | call, only the named target and format combination is |
| 68 | checked. If the target has not been set, or has been set to |
| 69 | <<default>>, then all the known target backends is |
| 70 | interrogated to determine a match. If the default target |
| 71 | matches, it is used. If not, exactly one target must recognize |
| 72 | the file, or an error results. |
| 73 | |
| 74 | The function returns <<TRUE>> on success, otherwise <<FALSE>> |
| 75 | with one of the following error codes: |
| 76 | |
| 77 | o <<bfd_error_invalid_operation>> - |
| 78 | if <<format>> is not one of <<bfd_object>>, <<bfd_archive>> or |
| 79 | <<bfd_core>>. |
| 80 | |
| 81 | o <<bfd_error_system_call>> - |
| 82 | if an error occured during a read - even some file mismatches |
| 83 | can cause bfd_error_system_calls. |
| 84 | |
| 85 | o <<file_not_recognised>> - |
| 86 | none of the backends recognised the file format. |
| 87 | |
| 88 | o <<bfd_error_file_ambiguously_recognized>> - |
| 89 | more than one backend recognised the file format. |
| 90 | */ |
| 91 | |
| 92 | bfd_boolean |
| 93 | bfd_check_format (bfd *abfd, bfd_format format) |
| 94 | { |
| 95 | return bfd_check_format_matches (abfd, format, NULL); |
| 96 | } |
| 97 | |
| 98 | /* |
| 99 | FUNCTION |
| 100 | bfd_check_format_matches |
| 101 | |
| 102 | SYNOPSIS |
| 103 | bfd_boolean bfd_check_format_matches |
| 104 | (bfd *abfd, bfd_format format, char ***matching); |
| 105 | |
| 106 | DESCRIPTION |
| 107 | Like <<bfd_check_format>>, except when it returns FALSE with |
| 108 | <<bfd_errno>> set to <<bfd_error_file_ambiguously_recognized>>. In that |
| 109 | case, if @var{matching} is not NULL, it will be filled in with |
| 110 | a NULL-terminated list of the names of the formats that matched, |
| 111 | allocated with <<malloc>>. |
| 112 | Then the user may choose a format and try again. |
| 113 | |
| 114 | When done with the list that @var{matching} points to, the caller |
| 115 | should free it. |
| 116 | */ |
| 117 | |
| 118 | bfd_boolean |
| 119 | bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching) |
| 120 | { |
| 121 | extern const bfd_target binary_vec; |
| 122 | const bfd_target * const *target; |
| 123 | const bfd_target **matching_vector = NULL; |
| 124 | const bfd_target *save_targ, *right_targ, *ar_right_targ; |
| 125 | int match_count; |
| 126 | int ar_match_index; |
| 127 | |
| 128 | if (matching != NULL) |
| 129 | *matching = NULL; |
| 130 | |
| 131 | if (!bfd_read_p (abfd) |
| 132 | || (unsigned int) abfd->format >= (unsigned int) bfd_type_end) |
| 133 | { |
| 134 | bfd_set_error (bfd_error_invalid_operation); |
| 135 | return FALSE; |
| 136 | } |
| 137 | |
| 138 | if (abfd->format != bfd_unknown) |
| 139 | return abfd->format == format; |
| 140 | |
| 141 | /* Since the target type was defaulted, check them |
| 142 | all in the hope that one will be uniquely recognized. */ |
| 143 | save_targ = abfd->xvec; |
| 144 | match_count = 0; |
| 145 | ar_match_index = _bfd_target_vector_entries; |
| 146 | |
| 147 | if (matching != NULL || *bfd_associated_vector != NULL) |
| 148 | { |
| 149 | bfd_size_type amt; |
| 150 | |
| 151 | amt = sizeof (*matching_vector) * 2 * _bfd_target_vector_entries; |
| 152 | matching_vector = (const bfd_target **) bfd_malloc (amt); |
| 153 | if (!matching_vector) |
| 154 | return FALSE; |
| 155 | } |
| 156 | |
| 157 | right_targ = 0; |
| 158 | ar_right_targ = 0; |
| 159 | |
| 160 | /* Presume the answer is yes. */ |
| 161 | abfd->format = format; |
| 162 | |
| 163 | /* If the target type was explicitly specified, just check that target. */ |
| 164 | if (!abfd->target_defaulted) |
| 165 | { |
| 166 | if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0) /* rewind! */ |
| 167 | goto err_ret; |
| 168 | |
| 169 | right_targ = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd)); |
| 170 | |
| 171 | if (right_targ) |
| 172 | goto ok_ret; |
| 173 | |
| 174 | /* For a long time the code has dropped through to check all |
| 175 | targets if the specified target was wrong. I don't know why, |
| 176 | and I'm reluctant to change it. However, in the case of an |
| 177 | archive, it can cause problems. If the specified target does |
| 178 | not permit archives (e.g., the binary target), then we should |
| 179 | not allow some other target to recognize it as an archive, but |
| 180 | should instead allow the specified target to recognize it as an |
| 181 | object. When I first made this change, it broke the PE target, |
| 182 | because the specified pei-i386 target did not recognize the |
| 183 | actual pe-i386 archive. Since there may be other problems of |
| 184 | this sort, I changed this test to check only for the binary |
| 185 | target. */ |
| 186 | if (format == bfd_archive && save_targ == &binary_vec) |
| 187 | goto err_unrecog; |
| 188 | } |
| 189 | |
| 190 | for (target = bfd_target_vector; *target != NULL; target++) |
| 191 | { |
| 192 | const bfd_target *temp; |
| 193 | bfd_error_type err; |
| 194 | |
| 195 | /* Don't check the default target twice. */ |
| 196 | if (*target == &binary_vec |
| 197 | || (!abfd->target_defaulted && *target == save_targ)) |
| 198 | continue; |
| 199 | |
| 200 | abfd->xvec = *target; /* Change BFD's target temporarily. */ |
| 201 | |
| 202 | if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0) |
| 203 | goto err_ret; |
| 204 | |
| 205 | /* If _bfd_check_format neglects to set bfd_error, assume |
| 206 | bfd_error_wrong_format. We didn't used to even pay any |
| 207 | attention to bfd_error, so I suspect that some |
| 208 | _bfd_check_format might have this problem. */ |
| 209 | bfd_set_error (bfd_error_wrong_format); |
| 210 | |
| 211 | temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd)); |
| 212 | |
| 213 | if (temp && (abfd->format != bfd_archive || bfd_has_map (abfd))) |
| 214 | { |
| 215 | /* This format checks out as ok! */ |
| 216 | right_targ = temp; |
| 217 | |
| 218 | /* If this is the default target, accept it, even if other |
| 219 | targets might match. People who want those other targets |
| 220 | have to set the GNUTARGET variable. */ |
| 221 | if (temp == bfd_default_vector[0]) |
| 222 | { |
| 223 | match_count = 1; |
| 224 | break; |
| 225 | } |
| 226 | |
| 227 | if (matching_vector) |
| 228 | matching_vector[match_count] = temp; |
| 229 | match_count++; |
| 230 | } |
| 231 | else if (temp |
| 232 | || (err = bfd_get_error ()) == bfd_error_wrong_object_format |
| 233 | || err == bfd_error_file_ambiguously_recognized) |
| 234 | { |
| 235 | /* An archive with no armap or objects of the wrong type, |
| 236 | or an ambiguous match. We want this target to match |
| 237 | if we get no better matches. */ |
| 238 | if (ar_right_targ != bfd_default_vector[0]) |
| 239 | ar_right_targ = *target; |
| 240 | if (matching_vector) |
| 241 | matching_vector[ar_match_index] = *target; |
| 242 | ar_match_index++; |
| 243 | } |
| 244 | else if (err != bfd_error_wrong_format) |
| 245 | goto err_ret; |
| 246 | } |
| 247 | |
| 248 | if (match_count == 0) |
| 249 | { |
| 250 | /* Try partial matches. */ |
| 251 | right_targ = ar_right_targ; |
| 252 | |
| 253 | if (right_targ == bfd_default_vector[0]) |
| 254 | { |
| 255 | match_count = 1; |
| 256 | } |
| 257 | else |
| 258 | { |
| 259 | match_count = ar_match_index - _bfd_target_vector_entries; |
| 260 | |
| 261 | if (matching_vector && match_count > 1) |
| 262 | memcpy (matching_vector, |
| 263 | matching_vector + _bfd_target_vector_entries, |
| 264 | sizeof (*matching_vector) * match_count); |
| 265 | } |
| 266 | } |
| 267 | |
| 268 | if (match_count > 1) |
| 269 | { |
| 270 | const bfd_target * const *assoc = bfd_associated_vector; |
| 271 | |
| 272 | while ((right_targ = *assoc++) != NULL) |
| 273 | { |
| 274 | int i = match_count; |
| 275 | |
| 276 | while (--i >= 0) |
| 277 | if (matching_vector[i] == right_targ) |
| 278 | break; |
| 279 | |
| 280 | if (i >= 0) |
| 281 | { |
| 282 | match_count = 1; |
| 283 | break; |
| 284 | } |
| 285 | } |
| 286 | } |
| 287 | |
| 288 | if (match_count == 1) |
| 289 | { |
| 290 | ok_ret: |
| 291 | abfd->xvec = right_targ; /* Change BFD's target permanently. */ |
| 292 | |
| 293 | /* If the file was opened for update, then `output_has_begun' |
| 294 | some time ago when the file was created. Do not recompute |
| 295 | sections sizes or alignments in _bfd_set_section_contents. |
| 296 | We can not set this flag until after checking the format, |
| 297 | because it will interfere with creation of BFD sections. */ |
| 298 | if (abfd->direction == both_direction) |
| 299 | abfd->output_has_begun = TRUE; |
| 300 | |
| 301 | if (matching_vector) |
| 302 | free (matching_vector); |
| 303 | return TRUE; /* File position has moved, BTW. */ |
| 304 | } |
| 305 | |
| 306 | if (match_count == 0) |
| 307 | { |
| 308 | err_unrecog: |
| 309 | bfd_set_error (bfd_error_file_not_recognized); |
| 310 | err_ret: |
| 311 | abfd->xvec = save_targ; |
| 312 | abfd->format = bfd_unknown; |
| 313 | if (matching_vector) |
| 314 | free (matching_vector); |
| 315 | return FALSE; |
| 316 | } |
| 317 | |
| 318 | abfd->xvec = save_targ; /* Restore original target type. */ |
| 319 | abfd->format = bfd_unknown; /* Restore original format. */ |
| 320 | bfd_set_error (bfd_error_file_ambiguously_recognized); |
| 321 | |
| 322 | if (matching) |
| 323 | { |
| 324 | *matching = (char **) matching_vector; |
| 325 | matching_vector[match_count] = NULL; |
| 326 | /* Return target names. This is a little nasty. Maybe we |
| 327 | should do another bfd_malloc? */ |
| 328 | while (--match_count >= 0) |
| 329 | { |
| 330 | const char *name = matching_vector[match_count]->name; |
| 331 | *(const char **) &matching_vector[match_count] = name; |
| 332 | } |
| 333 | } |
| 334 | return FALSE; |
| 335 | } |
| 336 | |
| 337 | /* |
| 338 | FUNCTION |
| 339 | bfd_set_format |
| 340 | |
| 341 | SYNOPSIS |
| 342 | bfd_boolean bfd_set_format (bfd *abfd, bfd_format format); |
| 343 | |
| 344 | DESCRIPTION |
| 345 | This function sets the file format of the BFD @var{abfd} to the |
| 346 | format @var{format}. If the target set in the BFD does not |
| 347 | support the format requested, the format is invalid, or the BFD |
| 348 | is not open for writing, then an error occurs. |
| 349 | */ |
| 350 | |
| 351 | bfd_boolean |
| 352 | bfd_set_format (bfd *abfd, bfd_format format) |
| 353 | { |
| 354 | if (bfd_read_p (abfd) |
| 355 | || (unsigned int) abfd->format >= (unsigned int) bfd_type_end) |
| 356 | { |
| 357 | bfd_set_error (bfd_error_invalid_operation); |
| 358 | return FALSE; |
| 359 | } |
| 360 | |
| 361 | if (abfd->format != bfd_unknown) |
| 362 | return abfd->format == format; |
| 363 | |
| 364 | /* Presume the answer is yes. */ |
| 365 | abfd->format = format; |
| 366 | |
| 367 | if (!BFD_SEND_FMT (abfd, _bfd_set_format, (abfd))) |
| 368 | { |
| 369 | abfd->format = bfd_unknown; |
| 370 | return FALSE; |
| 371 | } |
| 372 | |
| 373 | return TRUE; |
| 374 | } |
| 375 | |
| 376 | /* |
| 377 | FUNCTION |
| 378 | bfd_format_string |
| 379 | |
| 380 | SYNOPSIS |
| 381 | const char *bfd_format_string (bfd_format format); |
| 382 | |
| 383 | DESCRIPTION |
| 384 | Return a pointer to a const string |
| 385 | <<invalid>>, <<object>>, <<archive>>, <<core>>, or <<unknown>>, |
| 386 | depending upon the value of @var{format}. |
| 387 | */ |
| 388 | |
| 389 | const char * |
| 390 | bfd_format_string (bfd_format format) |
| 391 | { |
| 392 | if (((int) format < (int) bfd_unknown) |
| 393 | || ((int) format >= (int) bfd_type_end)) |
| 394 | return "invalid"; |
| 395 | |
| 396 | switch (format) |
| 397 | { |
| 398 | case bfd_object: |
| 399 | return "object"; /* Linker/assembler/compiler output. */ |
| 400 | case bfd_archive: |
| 401 | return "archive"; /* Object archive file. */ |
| 402 | case bfd_core: |
| 403 | return "core"; /* Core dump. */ |
| 404 | default: |
| 405 | return "unknown"; |
| 406 | } |
| 407 | } |