1 /* $NetBSD: libdwarf_attr.c,v 1.6 2026/05/17 21:40:49 jkoshy Exp $ */ 2 3 /*- 4 * Copyright (c) 2007 John Birrell (jb (at) freebsd.org) 5 * Copyright (c) 2009-2011,2023 Kai Wang 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include "_libdwarf.h" 31 32 __RCSID("$NetBSD: libdwarf_attr.c,v 1.6 2026/05/17 21:40:49 jkoshy Exp $"); 33 ELFTC_VCSID("Id: libdwarf_attr.c 4039 2024-03-15 04:07:32Z kaiwang27"); 34 35 int 36 _dwarf_attr_alloc(Dwarf_Die die, Dwarf_Attribute *atp, Dwarf_Error *error) 37 { 38 Dwarf_Attribute at; 39 40 assert(die != NULL); 41 assert(atp != NULL); 42 43 if ((at = calloc(1, sizeof(struct _Dwarf_Attribute))) == NULL) { 44 DWARF_SET_ERROR(die->die_dbg, error, DW_DLE_MEMORY); 45 return (DW_DLE_MEMORY); 46 } 47 48 *atp = at; 49 50 return (DW_DLE_NONE); 51 } 52 53 static int 54 _dwarf_attr_add(Dwarf_Die die, Dwarf_Attribute atref, Dwarf_Attribute *atp, 55 Dwarf_Error *error) 56 { 57 Dwarf_Attribute at; 58 int ret; 59 60 if ((ret = _dwarf_attr_alloc(die, &at, error)) != DW_DLE_NONE) 61 return (ret); 62 63 memcpy(at, atref, sizeof(struct _Dwarf_Attribute)); 64 65 STAILQ_INSERT_TAIL(&die->die_attr, at, at_next); 66 67 /* Save a pointer to the attribute name if this is one. */ 68 if (at->at_attrib == DW_AT_name) { 69 switch (at->at_form) { 70 case DW_FORM_strp: 71 die->die_name = at->u[1].s; 72 break; 73 case DW_FORM_string: 74 die->die_name = at->u[0].s; 75 break; 76 default: 77 break; 78 } 79 } 80 81 if (atp != NULL) 82 *atp = at; 83 84 return (DW_DLE_NONE); 85 } 86 87 Dwarf_Attribute 88 _dwarf_attr_find(Dwarf_Die die, Dwarf_Half attr) 89 { 90 Dwarf_Attribute at; 91 92 STAILQ_FOREACH(at, &die->die_attr, at_next) { 93 if (at->at_attrib == attr) 94 break; 95 } 96 97 return (at); 98 } 99 100 int 101 _dwarf_attr_init(Dwarf_Debug dbg, Dwarf_Section *ds, uint64_t *offsetp, 102 int dwarf_size, Dwarf_CU cu, Dwarf_Die die, Dwarf_AttrDef ad, 103 uint64_t form, int indirect, Dwarf_Error *error) 104 { 105 struct _Dwarf_Attribute atref; 106 int ret; 107 108 ret = DW_DLE_NONE; 109 memset(&atref, 0, sizeof(atref)); 110 atref.at_die = die; 111 atref.at_offset = *offsetp; 112 atref.at_attrib = ad->ad_attrib; 113 atref.at_form = indirect ? form : ad->ad_form; 114 atref.at_indirect = indirect; 115 atref.at_ld = NULL; 116 117 switch (form) { 118 case DW_FORM_addr: 119 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 120 cu->cu_pointer_size); 121 break; 122 case DW_FORM_block: 123 case DW_FORM_exprloc: 124 atref.u[0].u64 = _dwarf_read_uleb128(ds->ds_data, offsetp); 125 atref.u[1].u8p = _dwarf_read_block(ds->ds_data, offsetp, 126 atref.u[0].u64); 127 break; 128 case DW_FORM_block1: 129 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 1); 130 atref.u[1].u8p = _dwarf_read_block(ds->ds_data, offsetp, 131 atref.u[0].u64); 132 break; 133 case DW_FORM_block2: 134 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 2); 135 atref.u[1].u8p = _dwarf_read_block(ds->ds_data, offsetp, 136 atref.u[0].u64); 137 break; 138 case DW_FORM_block4: 139 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 4); 140 atref.u[1].u8p = _dwarf_read_block(ds->ds_data, offsetp, 141 atref.u[0].u64); 142 break; 143 case DW_FORM_data1: 144 case DW_FORM_flag: 145 case DW_FORM_ref1: 146 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 1); 147 break; 148 case DW_FORM_data2: 149 case DW_FORM_ref2: 150 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 2); 151 break; 152 case DW_FORM_data4: 153 case DW_FORM_ref4: 154 case DW_FORM_ref_sup4: 155 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 4); 156 break; 157 case DW_FORM_data8: 158 case DW_FORM_ref8: 159 case DW_FORM_ref_sup8: 160 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 8); 161 break; 162 case DW_FORM_indirect: 163 form = _dwarf_read_uleb128(ds->ds_data, offsetp); 164 return (_dwarf_attr_init(dbg, ds, offsetp, dwarf_size, cu, die, 165 ad, form, 1, error)); 166 case DW_FORM_ref_addr: 167 if (cu->cu_version == 2) 168 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 169 cu->cu_pointer_size); 170 else 171 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 172 dwarf_size); 173 break; 174 case DW_FORM_ref_udata: 175 case DW_FORM_udata: 176 case DW_FORM_loclistx: 177 case DW_FORM_rnglistx: 178 atref.u[0].u64 = _dwarf_read_uleb128(ds->ds_data, offsetp); 179 break; 180 case DW_FORM_sdata: 181 atref.u[0].s64 = _dwarf_read_sleb128(ds->ds_data, offsetp); 182 break; 183 case DW_FORM_sec_offset: 184 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, dwarf_size); 185 break; 186 case DW_FORM_string: 187 atref.u[0].s = _dwarf_read_string(ds->ds_data, ds->ds_size, 188 offsetp); 189 break; 190 case DW_FORM_strp: 191 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, dwarf_size); 192 atref.u[1].s = _dwarf_strtab_get_table(dbg) + atref.u[0].u64; 193 break; 194 case DW_FORM_ref_sig8: 195 atref.u[0].u64 = 8; 196 atref.u[1].u8p = _dwarf_read_block(ds->ds_data, offsetp, 197 atref.u[0].u64); 198 break; 199 case DW_FORM_flag_present: 200 /* This form has no value encoded in the DIE. */ 201 atref.u[0].u64 = 1; 202 break; 203 case DW_FORM_strx: 204 atref.u[0].u64 = _dwarf_read_uleb128(ds->ds_data, offsetp); 205 break; 206 case DW_FORM_addrx: 207 atref.u[0].u64 = _dwarf_read_uleb128(ds->ds_data, offsetp); 208 /* TODO: .debug_addr */ 209 break; 210 case DW_FORM_strp_sup: 211 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, dwarf_size); 212 /* TODO: supplementary object file. */ 213 break; 214 case DW_FORM_data16: 215 atref.u[0].u64 = 16; 216 atref.u[1].u8p = _dwarf_read_block(ds->ds_data, offsetp, 217 atref.u[0].u64); 218 break; 219 case DW_FORM_line_strp: 220 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, dwarf_size); 221 atref.u[1].s = _dwarf_strtab_get_line_table(dbg) + 222 atref.u[0].u64; 223 break; 224 case DW_FORM_implicit_const: 225 /* DWARF5 7.5.3 Implicit constant stored in attrdef. 226 This form has no value encoded in the DIE. */ 227 atref.u[0].s64 = ad->ad_const; 228 break; 229 case DW_FORM_strx1: 230 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 1); 231 break; 232 case DW_FORM_strx2: 233 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 1); 234 break; 235 case DW_FORM_strx3: 236 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 3); 237 break; 238 case DW_FORM_strx4: 239 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 4); 240 break; 241 case DW_FORM_addrx1: 242 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 1); 243 /* TODO: .debug_addr */ 244 break; 245 case DW_FORM_addrx2: 246 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 2); 247 /* TODO: .debug_addr */ 248 break; 249 case DW_FORM_addrx3: 250 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 3); 251 /* TODO: .debug_addr */ 252 break; 253 case DW_FORM_addrx4: 254 atref.u[0].u64 = dbg->read(ds->ds_data, offsetp, 4); 255 /* TODO: .debug_addr */ 256 break; 257 258 default: 259 DWARF_SET_ERROR(dbg, error, DW_DLE_ATTR_FORM_BAD); 260 ret = DW_DLE_ATTR_FORM_BAD; 261 break; 262 } 263 264 if (ret == DW_DLE_NONE) { 265 if (form == DW_FORM_block || form == DW_FORM_block1 || 266 form == DW_FORM_block2 || form == DW_FORM_block4) { 267 atref.at_block.bl_len = atref.u[0].u64; 268 atref.at_block.bl_data = atref.u[1].u8p; 269 } 270 ret = _dwarf_attr_add(die, &atref, NULL, error); 271 } 272 273 return (ret); 274 } 275 276 static int 277 _dwarf_attr_write(Dwarf_P_Debug dbg, Dwarf_P_Section ds, Dwarf_Rel_Section drs, 278 Dwarf_CU cu, Dwarf_Attribute at, int pass2, Dwarf_Error *error) 279 { 280 struct _Dwarf_P_Expr_Entry *ee; 281 uint64_t value, offset, bs; 282 int ret; 283 284 assert(dbg != NULL && ds != NULL && cu != NULL && at != NULL); 285 286 /* Fill in reference to other DIE in the second pass. */ 287 if (pass2) { 288 if (at->at_form != DW_FORM_ref4 && at->at_form != DW_FORM_ref8) 289 return (DW_DLE_NONE); 290 if (at->at_refdie == NULL || at->at_offset == 0) 291 return (DW_DLE_NONE); 292 offset = at->at_offset; 293 dbg->write(ds->ds_data, &offset, at->at_refdie->die_offset, 294 at->at_form == DW_FORM_ref4 ? 4 : 8); 295 return (DW_DLE_NONE); 296 } 297 298 switch (at->at_form) { 299 case DW_FORM_addr: 300 if (at->at_relsym) 301 ret = _dwarf_reloc_entry_add(dbg, drs, ds, 302 dwarf_drt_data_reloc, cu->cu_pointer_size, 303 ds->ds_size, at->at_relsym, at->u[0].u64, NULL, 304 error); 305 else 306 ret = WRITE_VALUE(at->u[0].u64, cu->cu_pointer_size); 307 break; 308 case DW_FORM_block: 309 case DW_FORM_block1: 310 case DW_FORM_block2: 311 case DW_FORM_block4: 312 /* Write block size. */ 313 if (at->at_form == DW_FORM_block) { 314 ret = _dwarf_write_uleb128_alloc(&ds->ds_data, 315 &ds->ds_cap, &ds->ds_size, at->u[0].u64, error); 316 if (ret != DW_DLE_NONE) 317 break; 318 } else { 319 if (at->at_form == DW_FORM_block1) 320 bs = 1; 321 else if (at->at_form == DW_FORM_block2) 322 bs = 2; 323 else 324 bs = 4; 325 ret = WRITE_VALUE(at->u[0].u64, bs); 326 if (ret != DW_DLE_NONE) 327 break; 328 } 329 330 /* Keep block data offset for later use. */ 331 offset = ds->ds_size; 332 333 /* Write block data. */ 334 ret = WRITE_BLOCK(at->u[1].u8p, at->u[0].u64); 335 if (ret != DW_DLE_NONE) 336 break; 337 if (at->at_expr == NULL) 338 break; 339 340 /* Generate relocation entry for DW_OP_addr expressions. */ 341 STAILQ_FOREACH(ee, &at->at_expr->pe_eelist, ee_next) { 342 if (ee->ee_loc.lr_atom != DW_OP_addr || ee->ee_sym == 0) 343 continue; 344 ret = _dwarf_reloc_entry_add(dbg, drs, ds, 345 dwarf_drt_data_reloc, dbg->dbg_pointer_size, 346 offset + ee->ee_loc.lr_offset + 1, ee->ee_sym, 347 ee->ee_loc.lr_number, NULL, error); 348 if (ret != DW_DLE_NONE) 349 break; 350 } 351 break; 352 case DW_FORM_data1: 353 case DW_FORM_flag: 354 case DW_FORM_ref1: 355 ret = WRITE_VALUE(at->u[0].u64, 1); 356 break; 357 case DW_FORM_data2: 358 case DW_FORM_ref2: 359 ret = WRITE_VALUE(at->u[0].u64, 2); 360 break; 361 case DW_FORM_data4: 362 if (at->at_relsym || at->at_relsec != NULL) 363 ret = _dwarf_reloc_entry_add(dbg, drs, ds, 364 dwarf_drt_data_reloc, 4, ds->ds_size, at->at_relsym, 365 at->u[0].u64, at->at_relsec, error); 366 else 367 ret = WRITE_VALUE(at->u[0].u64, 4); 368 break; 369 case DW_FORM_data8: 370 if (at->at_relsym || at->at_relsec != NULL) 371 ret = _dwarf_reloc_entry_add(dbg, drs, ds, 372 dwarf_drt_data_reloc, 8, ds->ds_size, at->at_relsym, 373 at->u[0].u64, at->at_relsec, error); 374 else 375 ret = WRITE_VALUE(at->u[0].u64, 8); 376 break; 377 case DW_FORM_ref4: 378 case DW_FORM_ref8: 379 /* 380 * The value of ref4 and ref8 could be a reference to another 381 * DIE within the CU. And if we don't know the ref DIE's 382 * offset at the moement, then we remember at_offset and fill 383 * it in the second pass. 384 */ 385 if (at->at_refdie) { 386 value = at->at_refdie->die_offset; 387 if (value == 0) { 388 cu->cu_pass2 = 1; 389 at->at_offset = ds->ds_size; 390 } 391 } else 392 value = at->u[0].u64; 393 ret = WRITE_VALUE(value, at->at_form == DW_FORM_ref4 ? 4 : 8); 394 break; 395 case DW_FORM_indirect: 396 /* TODO. */ 397 DWARF_SET_ERROR(dbg, error, DW_DLE_ATTR_FORM_BAD); 398 ret = DW_DLE_ATTR_FORM_BAD; 399 break; 400 case DW_FORM_ref_addr: 401 /* DWARF2 format. */ 402 if (at->at_relsym) 403 ret = _dwarf_reloc_entry_add(dbg, drs, ds, 404 dwarf_drt_data_reloc, cu->cu_pointer_size, 405 ds->ds_size, at->at_relsym, at->u[0].u64, NULL, 406 error); 407 else 408 ret = WRITE_VALUE(at->u[0].u64, cu->cu_pointer_size); 409 break; 410 case DW_FORM_ref_udata: 411 case DW_FORM_udata: 412 ret = WRITE_ULEB128(at->u[0].u64); 413 break; 414 case DW_FORM_sdata: 415 ret = WRITE_SLEB128(at->u[0].s64); 416 break; 417 case DW_FORM_string: 418 assert(at->u[0].s != NULL); 419 ret = WRITE_STRING(at->u[0].s); 420 break; 421 case DW_FORM_strp: 422 ret = _dwarf_reloc_entry_add(dbg, drs, ds, dwarf_drt_data_reloc, 423 4, ds->ds_size, 0, at->u[0].u64, ".debug_str", error); 424 break; 425 default: 426 DWARF_SET_ERROR(dbg, error, DW_DLE_ATTR_FORM_BAD); 427 ret = DW_DLE_ATTR_FORM_BAD; 428 break; 429 } 430 431 return (ret); 432 } 433 434 int 435 _dwarf_add_AT_dataref(Dwarf_P_Debug dbg, Dwarf_P_Die die, Dwarf_Half attr, 436 Dwarf_Unsigned pc_value, Dwarf_Unsigned sym_index, const char *secname, 437 Dwarf_P_Attribute *atp, Dwarf_Error *error) 438 { 439 Dwarf_Attribute at; 440 int ret; 441 442 assert(dbg != NULL && die != NULL); 443 444 if ((ret = _dwarf_attr_alloc(die, &at, error)) != DW_DLE_NONE) 445 return (ret); 446 447 at->at_die = die; 448 at->at_attrib = attr; 449 if (dbg->dbg_pointer_size == 4) 450 at->at_form = DW_FORM_data4; 451 else 452 at->at_form = DW_FORM_data8; 453 at->at_relsym = sym_index; 454 at->at_relsec = secname; 455 at->u[0].u64 = pc_value; 456 457 STAILQ_INSERT_TAIL(&die->die_attr, at, at_next); 458 459 if (atp) 460 *atp = at; 461 462 return (DW_DLE_NONE); 463 } 464 465 int 466 _dwarf_add_string_attr(Dwarf_P_Die die, Dwarf_P_Attribute *atp, Dwarf_Half attr, 467 char *string, Dwarf_Error *error) 468 { 469 Dwarf_Attribute at; 470 Dwarf_Debug dbg; 471 int ret; 472 473 dbg = die != NULL ? die->die_dbg : NULL; 474 475 assert(atp != NULL); 476 477 if (die == NULL || string == NULL) { 478 DWARF_SET_ERROR(dbg, error, DW_DLE_ARGUMENT); 479 return (DW_DLE_ARGUMENT); 480 } 481 482 if ((ret = _dwarf_attr_alloc(die, &at, error)) != DW_DLE_NONE) 483 return (ret); 484 485 at->at_die = die; 486 at->at_attrib = attr; 487 at->at_form = DW_FORM_strp; 488 if ((ret = _dwarf_strtab_add(dbg, string, &at->u[0].u64, 489 error)) != DW_DLE_NONE) { 490 free(at); 491 return (ret); 492 } 493 at->u[1].s = _dwarf_strtab_get_table(dbg) + at->u[0].u64; 494 495 *atp = at; 496 497 STAILQ_INSERT_TAIL(&die->die_attr, at, at_next); 498 499 return (DW_DLE_NONE); 500 } 501 502 int 503 _dwarf_attr_gen(Dwarf_P_Debug dbg, Dwarf_P_Section ds, Dwarf_Rel_Section drs, 504 Dwarf_CU cu, Dwarf_Die die, int pass2, Dwarf_Error *error) 505 { 506 Dwarf_Attribute at; 507 int ret; 508 509 assert(dbg != NULL && ds != NULL && cu != NULL && die != NULL); 510 511 STAILQ_FOREACH(at, &die->die_attr, at_next) { 512 ret = _dwarf_attr_write(dbg, ds, drs, cu, at, pass2, error); 513 if (ret != DW_DLE_NONE) 514 return (ret); 515 } 516 517 return (DW_DLE_NONE); 518 } 519
Indexes created Mon Oct 19 00:25:19 UTC 2026