| 1 | /* simple-object.c -- simple routines to read and write object files. |
| 2 | Copyright (C) 2010-2018 Free Software Foundation, Inc. |
| 3 | Written by Ian Lance Taylor, Google. |
| 4 | |
| 5 | This program is free software; you can redistribute it and/or modify it |
| 6 | under the terms of the GNU General Public License as published by the |
| 7 | Free Software Foundation; either version 2, or (at your option) any |
| 8 | later version. |
| 9 | |
| 10 | This program is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | GNU General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU General Public License |
| 16 | along with this program; if not, write to the Free Software |
| 17 | Foundation, 51 Franklin Street - Fifth Floor, |
| 18 | Boston, MA 02110-1301, USA. */ |
| 19 | |
| 20 | #include "config.h" |
| 21 | #include "libiberty.h" |
| 22 | #include "simple-object.h" |
| 23 | |
| 24 | #include <errno.h> |
| 25 | #include <fcntl.h> |
| 26 | |
| 27 | #ifdef HAVE_STDLIB_H |
| 28 | #include <stdlib.h> |
| 29 | #endif |
| 30 | |
| 31 | #ifdef HAVE_STDINT_H |
| 32 | #include <stdint.h> |
| 33 | #endif |
| 34 | |
| 35 | #ifdef HAVE_STRING_H |
| 36 | #include <string.h> |
| 37 | #endif |
| 38 | |
| 39 | #ifdef HAVE_INTTYPES_H |
| 40 | #include <inttypes.h> |
| 41 | #endif |
| 42 | |
| 43 | #ifndef SEEK_SET |
| 44 | #define SEEK_SET 0 |
| 45 | #endif |
| 46 | |
| 47 | #include "simple-object-common.h" |
| 48 | |
| 49 | /* The known object file formats. */ |
| 50 | |
| 51 | static const struct simple_object_functions * const format_functions[] = |
| 52 | { |
| 53 | &simple_object_elf_functions, |
| 54 | &simple_object_mach_o_functions, |
| 55 | &simple_object_coff_functions, |
| 56 | &simple_object_xcoff_functions |
| 57 | }; |
| 58 | |
| 59 | /* Read data from a file using the simple_object error reporting |
| 60 | conventions. */ |
| 61 | |
| 62 | int |
| 63 | simple_object_internal_read (int descriptor, off_t offset, |
| 64 | unsigned char *buffer, size_t size, |
| 65 | const char **errmsg, int *err) |
| 66 | { |
| 67 | if (lseek (descriptor, offset, SEEK_SET) < 0) |
| 68 | { |
| 69 | *errmsg = "lseek"; |
| 70 | *err = errno; |
| 71 | return 0; |
| 72 | } |
| 73 | |
| 74 | do |
| 75 | { |
| 76 | ssize_t got = read (descriptor, buffer, size); |
| 77 | if (got == 0) |
| 78 | break; |
| 79 | else if (got > 0) |
| 80 | { |
| 81 | buffer += got; |
| 82 | size -= got; |
| 83 | } |
| 84 | else if (errno != EINTR) |
| 85 | { |
| 86 | *errmsg = "read"; |
| 87 | *err = errno; |
| 88 | return 0; |
| 89 | } |
| 90 | } |
| 91 | while (size > 0); |
| 92 | |
| 93 | if (size > 0) |
| 94 | { |
| 95 | *errmsg = "file too short"; |
| 96 | *err = 0; |
| 97 | return 0; |
| 98 | } |
| 99 | |
| 100 | return 1; |
| 101 | } |
| 102 | |
| 103 | /* Write data to a file using the simple_object error reporting |
| 104 | conventions. */ |
| 105 | |
| 106 | int |
| 107 | simple_object_internal_write (int descriptor, off_t offset, |
| 108 | const unsigned char *buffer, size_t size, |
| 109 | const char **errmsg, int *err) |
| 110 | { |
| 111 | if (lseek (descriptor, offset, SEEK_SET) < 0) |
| 112 | { |
| 113 | *errmsg = "lseek"; |
| 114 | *err = errno; |
| 115 | return 0; |
| 116 | } |
| 117 | |
| 118 | do |
| 119 | { |
| 120 | ssize_t wrote = write (descriptor, buffer, size); |
| 121 | if (wrote == 0) |
| 122 | break; |
| 123 | else if (wrote > 0) |
| 124 | { |
| 125 | buffer += wrote; |
| 126 | size -= wrote; |
| 127 | } |
| 128 | else if (errno != EINTR) |
| 129 | { |
| 130 | *errmsg = "write"; |
| 131 | *err = errno; |
| 132 | return 0; |
| 133 | } |
| 134 | } |
| 135 | while (size > 0); |
| 136 | |
| 137 | if (size > 0) |
| 138 | { |
| 139 | *errmsg = "short write"; |
| 140 | *err = 0; |
| 141 | return 0; |
| 142 | } |
| 143 | |
| 144 | return 1; |
| 145 | } |
| 146 | |
| 147 | /* Open for read. */ |
| 148 | |
| 149 | simple_object_read * |
| 150 | simple_object_start_read (int descriptor, off_t offset, |
| 151 | const char *segment_name, const char **errmsg, |
| 152 | int *err) |
| 153 | { |
| 154 | unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN]; |
| 155 | size_t len, i; |
| 156 | |
| 157 | if (!simple_object_internal_read (descriptor, offset, header, |
| 158 | SIMPLE_OBJECT_MATCH_HEADER_LEN, |
| 159 | errmsg, err)) |
| 160 | return NULL; |
| 161 | |
| 162 | len = sizeof (format_functions) / sizeof (format_functions[0]); |
| 163 | for (i = 0; i < len; ++i) |
| 164 | { |
| 165 | void *data; |
| 166 | |
| 167 | data = format_functions[i]->match (header, descriptor, offset, |
| 168 | segment_name, errmsg, err); |
| 169 | if (data != NULL) |
| 170 | { |
| 171 | simple_object_read *ret; |
| 172 | |
| 173 | ret = XNEW (simple_object_read); |
| 174 | ret->descriptor = descriptor; |
| 175 | ret->offset = offset; |
| 176 | ret->functions = format_functions[i]; |
| 177 | ret->data = data; |
| 178 | return ret; |
| 179 | } |
| 180 | } |
| 181 | |
| 182 | *errmsg = "file not recognized"; |
| 183 | *err = 0; |
| 184 | return NULL; |
| 185 | } |
| 186 | |
| 187 | /* Find all sections. */ |
| 188 | |
| 189 | const char * |
| 190 | simple_object_find_sections (simple_object_read *sobj, |
| 191 | int (*pfn) (void *, const char *, off_t, off_t), |
| 192 | void *data, |
| 193 | int *err) |
| 194 | { |
| 195 | return sobj->functions->find_sections (sobj, pfn, data, err); |
| 196 | } |
| 197 | |
| 198 | /* Internal data passed to find_one_section. */ |
| 199 | |
| 200 | struct find_one_section_data |
| 201 | { |
| 202 | /* The section we are looking for. */ |
| 203 | const char *name; |
| 204 | /* Where to store the section offset. */ |
| 205 | off_t *offset; |
| 206 | /* Where to store the section length. */ |
| 207 | off_t *length; |
| 208 | /* Set if the name is found. */ |
| 209 | int found; |
| 210 | }; |
| 211 | |
| 212 | /* Internal function passed to find_sections. */ |
| 213 | |
| 214 | static int |
| 215 | find_one_section (void *data, const char *name, off_t offset, off_t length) |
| 216 | { |
| 217 | struct find_one_section_data *fosd = (struct find_one_section_data *) data; |
| 218 | |
| 219 | if (strcmp (name, fosd->name) != 0) |
| 220 | return 1; |
| 221 | |
| 222 | *fosd->offset = offset; |
| 223 | *fosd->length = length; |
| 224 | fosd->found = 1; |
| 225 | |
| 226 | /* Stop iteration. */ |
| 227 | return 0; |
| 228 | } |
| 229 | |
| 230 | /* Find a section. */ |
| 231 | |
| 232 | int |
| 233 | simple_object_find_section (simple_object_read *sobj, const char *name, |
| 234 | off_t *offset, off_t *length, |
| 235 | const char **errmsg, int *err) |
| 236 | { |
| 237 | struct find_one_section_data fosd; |
| 238 | |
| 239 | fosd.name = name; |
| 240 | fosd.offset = offset; |
| 241 | fosd.length = length; |
| 242 | fosd.found = 0; |
| 243 | |
| 244 | *errmsg = simple_object_find_sections (sobj, find_one_section, |
| 245 | (void *) &fosd, err); |
| 246 | if (*errmsg != NULL) |
| 247 | return 0; |
| 248 | if (!fosd.found) |
| 249 | return 0; |
| 250 | return 1; |
| 251 | } |
| 252 | |
| 253 | /* Callback to identify and rename LTO debug sections by name. |
| 254 | Returns non-NULL if NAME is a LTO debug section, NULL if not. |
| 255 | If RENAME is true it will rename LTO debug sections to non-LTO |
| 256 | ones. */ |
| 257 | |
| 258 | static char * |
| 259 | handle_lto_debug_sections (const char *name, int rename) |
| 260 | { |
| 261 | char *newname = rename ? XCNEWVEC (char, strlen (name) + 1) |
| 262 | : xstrdup (name); |
| 263 | |
| 264 | /* ??? So we can't use .gnu.lto_ prefixed sections as the assembler |
| 265 | complains about bogus section flags. Which means we need to arrange |
| 266 | for that to be fixed or .gnu.debuglto_ marked as SHF_EXCLUDE (to make |
| 267 | fat lto object tooling work for the fat part). */ |
| 268 | /* Also include corresponding reloc sections. */ |
| 269 | if (strncmp (name, ".rela", sizeof (".rela") - 1) == 0) |
| 270 | { |
| 271 | if (rename) |
| 272 | strncpy (newname, name, sizeof (".rela") - 1); |
| 273 | name += sizeof (".rela") - 1; |
| 274 | } |
| 275 | else if (strncmp (name, ".rel", sizeof (".rel") - 1) == 0) |
| 276 | { |
| 277 | if (rename) |
| 278 | strncpy (newname, name, sizeof (".rel") - 1); |
| 279 | name += sizeof (".rel") - 1; |
| 280 | } |
| 281 | /* ??? For now this handles both .gnu.lto_ and .gnu.debuglto_ prefixed |
| 282 | sections. */ |
| 283 | /* Copy LTO debug sections and rename them to their non-LTO name. */ |
| 284 | if (strncmp (name, ".gnu.debuglto_", sizeof (".gnu.debuglto_") - 1) == 0) |
| 285 | return rename ? strcat (newname, name + sizeof (".gnu.debuglto_") - 1) : newname; |
| 286 | else if (strncmp (name, ".gnu.lto_.debug_", |
| 287 | sizeof (".gnu.lto_.debug_") -1) == 0) |
| 288 | return rename ? strcat (newname, name + sizeof (".gnu.lto_") - 1) : newname; |
| 289 | /* Copy over .note.GNU-stack section under the same name if present. */ |
| 290 | else if (strcmp (name, ".note.GNU-stack") == 0) |
| 291 | return strcpy (newname, name); |
| 292 | /* Copy over .comment section under the same name if present. Solaris |
| 293 | ld uses them to relax its checking of ELF gABI access rules for |
| 294 | COMDAT sections in objects produced by GCC. */ |
| 295 | else if (strcmp (name, ".comment") == 0) |
| 296 | return strcpy (newname, name); |
| 297 | free (newname); |
| 298 | return NULL; |
| 299 | } |
| 300 | |
| 301 | /* Wrapper for handle_lto_debug_sections. */ |
| 302 | |
| 303 | static char * |
| 304 | handle_lto_debug_sections_rename (const char *name) |
| 305 | { |
| 306 | return handle_lto_debug_sections (name, 1); |
| 307 | } |
| 308 | |
| 309 | /* Wrapper for handle_lto_debug_sections. */ |
| 310 | |
| 311 | static char * |
| 312 | handle_lto_debug_sections_norename (const char *name) |
| 313 | { |
| 314 | return handle_lto_debug_sections (name, 0); |
| 315 | } |
| 316 | |
| 317 | /* Copy LTO debug sections. */ |
| 318 | |
| 319 | const char * |
| 320 | simple_object_copy_lto_debug_sections (simple_object_read *sobj, |
| 321 | const char *dest, int *err, int rename) |
| 322 | { |
| 323 | const char *errmsg; |
| 324 | simple_object_write *dest_sobj; |
| 325 | simple_object_attributes *attrs; |
| 326 | int outfd; |
| 327 | |
| 328 | if (! sobj->functions->copy_lto_debug_sections) |
| 329 | { |
| 330 | *err = EINVAL; |
| 331 | return "simple_object_copy_lto_debug_sections not implemented"; |
| 332 | } |
| 333 | |
| 334 | attrs = simple_object_fetch_attributes (sobj, &errmsg, err); |
| 335 | if (! attrs) |
| 336 | return errmsg; |
| 337 | dest_sobj = simple_object_start_write (attrs, NULL, &errmsg, err); |
| 338 | simple_object_release_attributes (attrs); |
| 339 | if (! dest_sobj) |
| 340 | return errmsg; |
| 341 | |
| 342 | errmsg = sobj->functions->copy_lto_debug_sections |
| 343 | (sobj, dest_sobj, |
| 344 | rename ? handle_lto_debug_sections_rename |
| 345 | : handle_lto_debug_sections_norename, err); |
| 346 | if (errmsg) |
| 347 | { |
| 348 | simple_object_release_write (dest_sobj); |
| 349 | return errmsg; |
| 350 | } |
| 351 | |
| 352 | outfd = creat (dest, 00777); |
| 353 | if (outfd == -1) |
| 354 | { |
| 355 | *err = errno; |
| 356 | simple_object_release_write (dest_sobj); |
| 357 | return "open failed"; |
| 358 | } |
| 359 | |
| 360 | errmsg = simple_object_write_to_file (dest_sobj, outfd, err); |
| 361 | close (outfd); |
| 362 | if (errmsg) |
| 363 | { |
| 364 | simple_object_release_write (dest_sobj); |
| 365 | return errmsg; |
| 366 | } |
| 367 | |
| 368 | simple_object_release_write (dest_sobj); |
| 369 | return NULL; |
| 370 | } |
| 371 | |
| 372 | /* Fetch attributes. */ |
| 373 | |
| 374 | simple_object_attributes * |
| 375 | simple_object_fetch_attributes (simple_object_read *sobj, const char **errmsg, |
| 376 | int *err) |
| 377 | { |
| 378 | void *data; |
| 379 | simple_object_attributes *ret; |
| 380 | |
| 381 | data = sobj->functions->fetch_attributes (sobj, errmsg, err); |
| 382 | if (data == NULL) |
| 383 | return NULL; |
| 384 | ret = XNEW (simple_object_attributes); |
| 385 | ret->functions = sobj->functions; |
| 386 | ret->data = data; |
| 387 | return ret; |
| 388 | } |
| 389 | |
| 390 | /* Release an simple_object_read. */ |
| 391 | |
| 392 | void |
| 393 | simple_object_release_read (simple_object_read *sobj) |
| 394 | { |
| 395 | sobj->functions->release_read (sobj->data); |
| 396 | XDELETE (sobj); |
| 397 | } |
| 398 | |
| 399 | /* Merge attributes. */ |
| 400 | |
| 401 | const char * |
| 402 | simple_object_attributes_merge (simple_object_attributes *to, |
| 403 | simple_object_attributes *from, |
| 404 | int *err) |
| 405 | { |
| 406 | if (to->functions != from->functions) |
| 407 | { |
| 408 | *err = 0; |
| 409 | return "different object file format"; |
| 410 | } |
| 411 | return to->functions->attributes_merge (to->data, from->data, err); |
| 412 | } |
| 413 | |
| 414 | /* Release an attributes structure. */ |
| 415 | |
| 416 | void |
| 417 | simple_object_release_attributes (simple_object_attributes *attrs) |
| 418 | { |
| 419 | attrs->functions->release_attributes (attrs->data); |
| 420 | XDELETE (attrs); |
| 421 | } |
| 422 | |
| 423 | /* Start creating an object file. */ |
| 424 | |
| 425 | simple_object_write * |
| 426 | simple_object_start_write (simple_object_attributes *attrs, |
| 427 | const char *segment_name, const char **errmsg, |
| 428 | int *err) |
| 429 | { |
| 430 | void *data; |
| 431 | simple_object_write *ret; |
| 432 | |
| 433 | data = attrs->functions->start_write (attrs->data, errmsg, err); |
| 434 | if (data == NULL) |
| 435 | return NULL; |
| 436 | ret = XNEW (simple_object_write); |
| 437 | ret->functions = attrs->functions; |
| 438 | ret->segment_name = segment_name ? xstrdup (segment_name) : NULL; |
| 439 | ret->sections = NULL; |
| 440 | ret->last_section = NULL; |
| 441 | ret->data = data; |
| 442 | return ret; |
| 443 | } |
| 444 | |
| 445 | /* Start creating a section. */ |
| 446 | |
| 447 | simple_object_write_section * |
| 448 | simple_object_write_create_section (simple_object_write *sobj, const char *name, |
| 449 | unsigned int align, |
| 450 | const char **errmsg ATTRIBUTE_UNUSED, |
| 451 | int *err ATTRIBUTE_UNUSED) |
| 452 | { |
| 453 | simple_object_write_section *ret; |
| 454 | |
| 455 | ret = XNEW (simple_object_write_section); |
| 456 | ret->next = NULL; |
| 457 | ret->name = xstrdup (name); |
| 458 | ret->align = align; |
| 459 | ret->buffers = NULL; |
| 460 | ret->last_buffer = NULL; |
| 461 | |
| 462 | if (sobj->last_section == NULL) |
| 463 | { |
| 464 | sobj->sections = ret; |
| 465 | sobj->last_section = ret; |
| 466 | } |
| 467 | else |
| 468 | { |
| 469 | sobj->last_section->next = ret; |
| 470 | sobj->last_section = ret; |
| 471 | } |
| 472 | |
| 473 | return ret; |
| 474 | } |
| 475 | |
| 476 | /* Add data to a section. */ |
| 477 | |
| 478 | const char * |
| 479 | simple_object_write_add_data (simple_object_write *sobj ATTRIBUTE_UNUSED, |
| 480 | simple_object_write_section *section, |
| 481 | const void *buffer, |
| 482 | size_t size, int copy, |
| 483 | int *err ATTRIBUTE_UNUSED) |
| 484 | { |
| 485 | struct simple_object_write_section_buffer *wsb; |
| 486 | |
| 487 | wsb = XNEW (struct simple_object_write_section_buffer); |
| 488 | wsb->next = NULL; |
| 489 | wsb->size = size; |
| 490 | |
| 491 | if (!copy) |
| 492 | { |
| 493 | wsb->buffer = buffer; |
| 494 | wsb->free_buffer = NULL; |
| 495 | } |
| 496 | else |
| 497 | { |
| 498 | wsb->free_buffer = (void *) XNEWVEC (char, size); |
| 499 | memcpy (wsb->free_buffer, buffer, size); |
| 500 | wsb->buffer = wsb->free_buffer; |
| 501 | } |
| 502 | |
| 503 | if (section->last_buffer == NULL) |
| 504 | { |
| 505 | section->buffers = wsb; |
| 506 | section->last_buffer = wsb; |
| 507 | } |
| 508 | else |
| 509 | { |
| 510 | section->last_buffer->next = wsb; |
| 511 | section->last_buffer = wsb; |
| 512 | } |
| 513 | |
| 514 | return NULL; |
| 515 | } |
| 516 | |
| 517 | /* Write the complete object file. */ |
| 518 | |
| 519 | const char * |
| 520 | simple_object_write_to_file (simple_object_write *sobj, int descriptor, |
| 521 | int *err) |
| 522 | { |
| 523 | return sobj->functions->write_to_file (sobj, descriptor, err); |
| 524 | } |
| 525 | |
| 526 | /* Release an simple_object_write. */ |
| 527 | |
| 528 | void |
| 529 | simple_object_release_write (simple_object_write *sobj) |
| 530 | { |
| 531 | simple_object_write_section *section; |
| 532 | |
| 533 | free (sobj->segment_name); |
| 534 | |
| 535 | section = sobj->sections; |
| 536 | while (section != NULL) |
| 537 | { |
| 538 | struct simple_object_write_section_buffer *buffer; |
| 539 | simple_object_write_section *next_section; |
| 540 | |
| 541 | buffer = section->buffers; |
| 542 | while (buffer != NULL) |
| 543 | { |
| 544 | struct simple_object_write_section_buffer *next_buffer; |
| 545 | |
| 546 | if (buffer->free_buffer != NULL) |
| 547 | XDELETEVEC (buffer->free_buffer); |
| 548 | next_buffer = buffer->next; |
| 549 | XDELETE (buffer); |
| 550 | buffer = next_buffer; |
| 551 | } |
| 552 | |
| 553 | next_section = section->next; |
| 554 | free (section->name); |
| 555 | XDELETE (section); |
| 556 | section = next_section; |
| 557 | } |
| 558 | |
| 559 | sobj->functions->release_write (sobj->data); |
| 560 | XDELETE (sobj); |
| 561 | } |