1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #define ELF_TARGET_ALL 30 #include <elf.h> 31 32 #include <sys/types.h> 33 #include <sys/sysmacros.h> 34 35 #include <unistd.h> 36 #include <strings.h> 37 #include <alloca.h> 38 #include <limits.h> 39 #include <stddef.h> 40 #include <stdlib.h> 41 #include <stdio.h> 42 #include <fcntl.h> 43 #include <errno.h> 44 #include <wait.h> 45 #include <assert.h> 46 #include <sys/ipc.h> 47 48 #include <dt_impl.h> 49 #include <dt_provider.h> 50 #include <dt_program.h> 51 #include <dt_string.h> 52 53 #define ESHDR_NULL 0 54 #define ESHDR_SHSTRTAB 1 55 #define ESHDR_DOF 2 56 #define ESHDR_STRTAB 3 57 #define ESHDR_SYMTAB 4 58 #define ESHDR_REL 5 59 #define ESHDR_NUM 6 60 61 #define PWRITE_SCN(index, data) \ 62 (lseek64(fd, (off64_t)elf_file.shdr[(index)].sh_offset, SEEK_SET) != \ 63 (off64_t)elf_file.shdr[(index)].sh_offset || \ 64 dt_write(dtp, fd, (data), elf_file.shdr[(index)].sh_size) != \ 65 elf_file.shdr[(index)].sh_size) 66 67 static const char DTRACE_SHSTRTAB32[] = "\0" 68 ".shstrtab\0" /* 1 */ 69 ".SUNW_dof\0" /* 11 */ 70 ".strtab\0" /* 21 */ 71 ".symtab\0" /* 29 */ 72 #ifdef __sparc 73 ".rela.SUNW_dof"; /* 37 */ 74 #else 75 ".rel.SUNW_dof"; /* 37 */ 76 #endif 77 78 static const char DTRACE_SHSTRTAB64[] = "\0" 79 ".shstrtab\0" /* 1 */ 80 ".SUNW_dof\0" /* 11 */ 81 ".strtab\0" /* 21 */ 82 ".symtab\0" /* 29 */ 83 ".rela.SUNW_dof"; /* 37 */ 84 85 static const char DOFSTR[] = "__SUNW_dof"; 86 static const char DOFLAZYSTR[] = "___SUNW_dof"; 87 88 typedef struct dt_link_pair { 89 struct dt_link_pair *dlp_next; /* next pair in linked list */ 90 void *dlp_str; /* buffer for string table */ 91 void *dlp_sym; /* buffer for symbol table */ 92 } dt_link_pair_t; 93 94 typedef struct dof_elf32 { 95 uint32_t de_nrel; /* relocation count */ 96 #ifdef __sparc 97 Elf32_Rela *de_rel; /* array of relocations for sparc */ 98 #else 99 Elf32_Rel *de_rel; /* array of relocations for x86 */ 100 #endif 101 uint32_t de_nsym; /* symbol count */ 102 Elf32_Sym *de_sym; /* array of symbols */ 103 uint32_t de_strlen; /* size of of string table */ 104 char *de_strtab; /* string table */ 105 uint32_t de_global; /* index of the first global symbol */ 106 } dof_elf32_t; 107 108 static int 109 prepare_elf32(dtrace_hdl_t *dtp, const dof_hdr_t *dof, dof_elf32_t *dep) 110 { 111 dof_sec_t *dofs, *s; 112 dof_relohdr_t *dofrh; 113 dof_relodesc_t *dofr; 114 char *strtab; 115 int i, j, nrel; 116 size_t strtabsz = 1; 117 uint32_t count = 0; 118 size_t base; 119 Elf32_Sym *sym; 120 #ifdef __sparc 121 Elf32_Rela *rel; 122 #else 123 Elf32_Rel *rel; 124 #endif 125 126 /*LINTED*/ 127 dofs = (dof_sec_t *)((char *)dof + dof->dofh_secoff); 128 129 /* 130 * First compute the size of the string table and the number of 131 * relocations present in the DOF. 132 */ 133 for (i = 0; i < dof->dofh_secnum; i++) { 134 if (dofs[i].dofs_type != DOF_SECT_URELHDR) 135 continue; 136 137 /*LINTED*/ 138 dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset); 139 140 s = &dofs[dofrh->dofr_strtab]; 141 strtab = (char *)dof + s->dofs_offset; 142 assert(strtab[0] == '\0'); 143 strtabsz += s->dofs_size - 1; 144 145 s = &dofs[dofrh->dofr_relsec]; 146 /*LINTED*/ 147 dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset); 148 count += s->dofs_size / s->dofs_entsize; 149 } 150 151 dep->de_strlen = strtabsz; 152 dep->de_nrel = count; 153 dep->de_nsym = count + 1; /* the first symbol is always null */ 154 155 if (dtp->dt_lazyload) { 156 dep->de_strlen += sizeof (DOFLAZYSTR); 157 dep->de_nsym++; 158 } else { 159 dep->de_strlen += sizeof (DOFSTR); 160 dep->de_nsym++; 161 } 162 163 if ((dep->de_rel = calloc(dep->de_nrel, 164 sizeof (dep->de_rel[0]))) == NULL) { 165 return (dt_set_errno(dtp, EDT_NOMEM)); 166 } 167 168 if ((dep->de_sym = calloc(dep->de_nsym, sizeof (Elf32_Sym))) == NULL) { 169 free(dep->de_rel); 170 return (dt_set_errno(dtp, EDT_NOMEM)); 171 } 172 173 if ((dep->de_strtab = calloc(dep->de_strlen, 1)) == NULL) { 174 free(dep->de_rel); 175 free(dep->de_sym); 176 return (dt_set_errno(dtp, EDT_NOMEM)); 177 } 178 179 count = 0; 180 strtabsz = 1; 181 dep->de_strtab[0] = '\0'; 182 rel = dep->de_rel; 183 sym = dep->de_sym; 184 dep->de_global = 1; 185 186 /* 187 * The first symbol table entry must be zeroed and is always ignored. 188 */ 189 bzero(sym, sizeof (Elf32_Sym)); 190 sym++; 191 192 /* 193 * Take a second pass through the DOF sections filling in the 194 * memory we allocated. 195 */ 196 for (i = 0; i < dof->dofh_secnum; i++) { 197 if (dofs[i].dofs_type != DOF_SECT_URELHDR) 198 continue; 199 200 /*LINTED*/ 201 dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset); 202 203 s = &dofs[dofrh->dofr_strtab]; 204 strtab = (char *)dof + s->dofs_offset; 205 bcopy(strtab + 1, dep->de_strtab + strtabsz, s->dofs_size); 206 base = strtabsz; 207 strtabsz += s->dofs_size - 1; 208 209 s = &dofs[dofrh->dofr_relsec]; 210 /*LINTED*/ 211 dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset); 212 nrel = s->dofs_size / s->dofs_entsize; 213 214 s = &dofs[dofrh->dofr_tgtsec]; 215 216 for (j = 0; j < nrel; j++) { 217 #if defined(__i386) || defined(__amd64) 218 rel->r_offset = s->dofs_offset + 219 dofr[j].dofr_offset; 220 rel->r_info = ELF32_R_INFO(count + dep->de_global, 221 R_386_32); 222 #elif defined(__sparc) 223 /* 224 * Add 4 bytes to hit the low half of this 64-bit 225 * big-endian address. 226 */ 227 rel->r_offset = s->dofs_offset + 228 dofr[j].dofr_offset + 4; 229 rel->r_info = ELF32_R_INFO(count + dep->de_global, 230 R_SPARC_32); 231 #else 232 #error unknown ISA 233 #endif 234 235 sym->st_name = base + dofr[j].dofr_name - 1; 236 sym->st_value = 0; 237 sym->st_size = 0; 238 sym->st_info = ELF32_ST_INFO(STB_GLOBAL, STT_FUNC); 239 sym->st_other = 0; 240 sym->st_shndx = SHN_UNDEF; 241 242 rel++; 243 sym++; 244 count++; 245 } 246 } 247 248 /* 249 * Add a symbol for the DOF itself. We use a different symbol for 250 * lazily and actively loaded DOF to make them easy to distinguish. 251 */ 252 sym->st_name = strtabsz; 253 sym->st_value = 0; 254 sym->st_size = dof->dofh_filesz; 255 sym->st_info = ELF32_ST_INFO(STB_GLOBAL, STT_OBJECT); 256 sym->st_other = 0; 257 sym->st_shndx = ESHDR_DOF; 258 sym++; 259 260 if (dtp->dt_lazyload) { 261 bcopy(DOFLAZYSTR, dep->de_strtab + strtabsz, 262 sizeof (DOFLAZYSTR)); 263 strtabsz += sizeof (DOFLAZYSTR); 264 } else { 265 bcopy(DOFSTR, dep->de_strtab + strtabsz, sizeof (DOFSTR)); 266 strtabsz += sizeof (DOFSTR); 267 } 268 269 assert(count == dep->de_nrel); 270 assert(strtabsz == dep->de_strlen); 271 272 return (0); 273 } 274 275 276 typedef struct dof_elf64 { 277 uint32_t de_nrel; 278 Elf64_Rela *de_rel; 279 uint32_t de_nsym; 280 Elf64_Sym *de_sym; 281 282 uint32_t de_strlen; 283 char *de_strtab; 284 285 uint32_t de_global; 286 } dof_elf64_t; 287 288 static int 289 prepare_elf64(dtrace_hdl_t *dtp, const dof_hdr_t *dof, dof_elf64_t *dep) 290 { 291 dof_sec_t *dofs, *s; 292 dof_relohdr_t *dofrh; 293 dof_relodesc_t *dofr; 294 char *strtab; 295 int i, j, nrel; 296 size_t strtabsz = 1; 297 uint32_t count = 0; 298 size_t base; 299 Elf64_Sym *sym; 300 Elf64_Rela *rel; 301 302 /*LINTED*/ 303 dofs = (dof_sec_t *)((char *)dof + dof->dofh_secoff); 304 305 /* 306 * First compute the size of the string table and the number of 307 * relocations present in the DOF. 308 */ 309 for (i = 0; i < dof->dofh_secnum; i++) { 310 if (dofs[i].dofs_type != DOF_SECT_URELHDR) 311 continue; 312 313 /*LINTED*/ 314 dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset); 315 316 s = &dofs[dofrh->dofr_strtab]; 317 strtab = (char *)dof + s->dofs_offset; 318 assert(strtab[0] == '\0'); 319 strtabsz += s->dofs_size - 1; 320 321 s = &dofs[dofrh->dofr_relsec]; 322 /*LINTED*/ 323 dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset); 324 count += s->dofs_size / s->dofs_entsize; 325 } 326 327 dep->de_strlen = strtabsz; 328 dep->de_nrel = count; 329 dep->de_nsym = count + 1; /* the first symbol is always null */ 330 331 if (dtp->dt_lazyload) { 332 dep->de_strlen += sizeof (DOFLAZYSTR); 333 dep->de_nsym++; 334 } else { 335 dep->de_strlen += sizeof (DOFSTR); 336 dep->de_nsym++; 337 } 338 339 if ((dep->de_rel = calloc(dep->de_nrel, 340 sizeof (dep->de_rel[0]))) == NULL) { 341 return (dt_set_errno(dtp, EDT_NOMEM)); 342 } 343 344 if ((dep->de_sym = calloc(dep->de_nsym, sizeof (Elf64_Sym))) == NULL) { 345 free(dep->de_rel); 346 return (dt_set_errno(dtp, EDT_NOMEM)); 347 } 348 349 if ((dep->de_strtab = calloc(dep->de_strlen, 1)) == NULL) { 350 free(dep->de_rel); 351 free(dep->de_sym); 352 return (dt_set_errno(dtp, EDT_NOMEM)); 353 } 354 355 count = 0; 356 strtabsz = 1; 357 dep->de_strtab[0] = '\0'; 358 rel = dep->de_rel; 359 sym = dep->de_sym; 360 dep->de_global = 1; 361 362 /* 363 * The first symbol table entry must be zeroed and is always ignored. 364 */ 365 bzero(sym, sizeof (Elf64_Sym)); 366 sym++; 367 368 /* 369 * Take a second pass through the DOF sections filling in the 370 * memory we allocated. 371 */ 372 for (i = 0; i < dof->dofh_secnum; i++) { 373 if (dofs[i].dofs_type != DOF_SECT_URELHDR) 374 continue; 375 376 /*LINTED*/ 377 dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset); 378 379 s = &dofs[dofrh->dofr_strtab]; 380 strtab = (char *)dof + s->dofs_offset; 381 bcopy(strtab + 1, dep->de_strtab + strtabsz, s->dofs_size); 382 base = strtabsz; 383 strtabsz += s->dofs_size - 1; 384 385 s = &dofs[dofrh->dofr_relsec]; 386 /*LINTED*/ 387 dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset); 388 nrel = s->dofs_size / s->dofs_entsize; 389 390 s = &dofs[dofrh->dofr_tgtsec]; 391 392 for (j = 0; j < nrel; j++) { 393 #if defined(__i386) || defined(__amd64) 394 rel->r_offset = s->dofs_offset + 395 dofr[j].dofr_offset; 396 rel->r_info = ELF64_R_INFO(count + dep->de_global, 397 R_AMD64_64); 398 #elif defined(__sparc) 399 rel->r_offset = s->dofs_offset + 400 dofr[j].dofr_offset; 401 rel->r_info = ELF64_R_INFO(count + dep->de_global, 402 R_SPARC_64); 403 #else 404 #error unknown ISA 405 #endif 406 407 sym->st_name = base + dofr[j].dofr_name - 1; 408 sym->st_value = 0; 409 sym->st_size = 0; 410 sym->st_info = GELF_ST_INFO(STB_GLOBAL, STT_FUNC); 411 sym->st_other = 0; 412 sym->st_shndx = SHN_UNDEF; 413 414 rel++; 415 sym++; 416 count++; 417 } 418 } 419 420 /* 421 * Add a symbol for the DOF itself. We use a different symbol for 422 * lazily and actively loaded DOF to make them easy to distinguish. 423 */ 424 sym->st_name = strtabsz; 425 sym->st_value = 0; 426 sym->st_size = dof->dofh_filesz; 427 sym->st_info = GELF_ST_INFO(STB_GLOBAL, STT_OBJECT); 428 sym->st_other = 0; 429 sym->st_shndx = ESHDR_DOF; 430 sym++; 431 432 if (dtp->dt_lazyload) { 433 bcopy(DOFLAZYSTR, dep->de_strtab + strtabsz, 434 sizeof (DOFLAZYSTR)); 435 strtabsz += sizeof (DOFLAZYSTR); 436 } else { 437 bcopy(DOFSTR, dep->de_strtab + strtabsz, sizeof (DOFSTR)); 438 strtabsz += sizeof (DOFSTR); 439 } 440 441 assert(count == dep->de_nrel); 442 assert(strtabsz == dep->de_strlen); 443 444 return (0); 445 } 446 447 /* 448 * Write out an ELF32 file prologue consisting of a header, section headers, 449 * and a section header string table. The DOF data will follow this prologue 450 * and complete the contents of the given ELF file. 451 */ 452 static int 453 dump_elf32(dtrace_hdl_t *dtp, const dof_hdr_t *dof, int fd) 454 { 455 struct { 456 Elf32_Ehdr ehdr; 457 Elf32_Shdr shdr[ESHDR_NUM]; 458 } elf_file; 459 460 Elf32_Shdr *shp; 461 Elf32_Off off; 462 dof_elf32_t de; 463 int ret = 0; 464 uint_t nshdr; 465 466 if (prepare_elf32(dtp, dof, &de) != 0) 467 return (-1); /* errno is set for us */ 468 469 /* 470 * If there are no relocations, we only need enough sections for 471 * the shstrtab and the DOF. 472 */ 473 nshdr = de.de_nrel == 0 ? ESHDR_SYMTAB + 1 : ESHDR_NUM; 474 475 bzero(&elf_file, sizeof (elf_file)); 476 477 elf_file.ehdr.e_ident[EI_MAG0] = ELFMAG0; 478 elf_file.ehdr.e_ident[EI_MAG1] = ELFMAG1; 479 elf_file.ehdr.e_ident[EI_MAG2] = ELFMAG2; 480 elf_file.ehdr.e_ident[EI_MAG3] = ELFMAG3; 481 elf_file.ehdr.e_ident[EI_VERSION] = EV_CURRENT; 482 elf_file.ehdr.e_ident[EI_CLASS] = ELFCLASS32; 483 #if defined(_BIG_ENDIAN) 484 elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2MSB; 485 #elif defined(_LITTLE_ENDIAN) 486 elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2LSB; 487 #endif 488 elf_file.ehdr.e_type = ET_REL; 489 #if defined(__sparc) 490 elf_file.ehdr.e_machine = EM_SPARC; 491 #elif defined(__i386) || defined(__amd64) 492 elf_file.ehdr.e_machine = EM_386; 493 #endif 494 elf_file.ehdr.e_version = EV_CURRENT; 495 elf_file.ehdr.e_shoff = sizeof (Elf32_Ehdr); 496 elf_file.ehdr.e_ehsize = sizeof (Elf32_Ehdr); 497 elf_file.ehdr.e_phentsize = sizeof (Elf32_Phdr); 498 elf_file.ehdr.e_shentsize = sizeof (Elf32_Shdr); 499 elf_file.ehdr.e_shnum = nshdr; 500 elf_file.ehdr.e_shstrndx = ESHDR_SHSTRTAB; 501 off = sizeof (elf_file) + nshdr * sizeof (Elf32_Shdr); 502 503 shp = &elf_file.shdr[ESHDR_SHSTRTAB]; 504 shp->sh_name = 1; /* DTRACE_SHSTRTAB32[1] = ".shstrtab" */ 505 shp->sh_type = SHT_STRTAB; 506 shp->sh_offset = off; 507 shp->sh_size = sizeof (DTRACE_SHSTRTAB32); 508 shp->sh_addralign = sizeof (char); 509 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8); 510 511 shp = &elf_file.shdr[ESHDR_DOF]; 512 shp->sh_name = 11; /* DTRACE_SHSTRTAB32[11] = ".SUNW_dof" */ 513 shp->sh_flags = SHF_ALLOC; 514 shp->sh_type = SHT_SUNW_dof; 515 shp->sh_offset = off; 516 shp->sh_size = dof->dofh_filesz; 517 shp->sh_addralign = 8; 518 off = shp->sh_offset + shp->sh_size; 519 520 shp = &elf_file.shdr[ESHDR_STRTAB]; 521 shp->sh_name = 21; /* DTRACE_SHSTRTAB32[21] = ".strtab" */ 522 shp->sh_flags = SHF_ALLOC; 523 shp->sh_type = SHT_STRTAB; 524 shp->sh_offset = off; 525 shp->sh_size = de.de_strlen; 526 shp->sh_addralign = sizeof (char); 527 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 4); 528 529 shp = &elf_file.shdr[ESHDR_SYMTAB]; 530 shp->sh_name = 29; /* DTRACE_SHSTRTAB32[29] = ".symtab" */ 531 shp->sh_flags = SHF_ALLOC; 532 shp->sh_type = SHT_SYMTAB; 533 shp->sh_entsize = sizeof (Elf32_Sym); 534 shp->sh_link = ESHDR_STRTAB; 535 shp->sh_offset = off; 536 shp->sh_info = de.de_global; 537 shp->sh_size = de.de_nsym * sizeof (Elf32_Sym); 538 shp->sh_addralign = 4; 539 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 4); 540 541 if (de.de_nrel == 0) { 542 if (dt_write(dtp, fd, &elf_file, 543 sizeof (elf_file)) != sizeof (elf_file) || 544 PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB32) || 545 PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) || 546 PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) || 547 PWRITE_SCN(ESHDR_DOF, dof)) { 548 ret = dt_set_errno(dtp, errno); 549 } 550 } else { 551 shp = &elf_file.shdr[ESHDR_REL]; 552 shp->sh_name = 37; /* DTRACE_SHSTRTAB32[37] = ".rel.SUNW_dof" */ 553 shp->sh_flags = SHF_ALLOC; 554 #ifdef __sparc 555 shp->sh_type = SHT_RELA; 556 #else 557 shp->sh_type = SHT_REL; 558 #endif 559 shp->sh_entsize = sizeof (de.de_rel[0]); 560 shp->sh_link = ESHDR_SYMTAB; 561 shp->sh_info = ESHDR_DOF; 562 shp->sh_offset = off; 563 shp->sh_size = de.de_nrel * sizeof (de.de_rel[0]); 564 shp->sh_addralign = 4; 565 566 if (dt_write(dtp, fd, &elf_file, 567 sizeof (elf_file)) != sizeof (elf_file) || 568 PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB32) || 569 PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) || 570 PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) || 571 PWRITE_SCN(ESHDR_REL, de.de_rel) || 572 PWRITE_SCN(ESHDR_DOF, dof)) { 573 ret = dt_set_errno(dtp, errno); 574 } 575 } 576 577 free(de.de_strtab); 578 free(de.de_sym); 579 free(de.de_rel); 580 581 return (ret); 582 } 583 584 /* 585 * Write out an ELF64 file prologue consisting of a header, section headers, 586 * and a section header string table. The DOF data will follow this prologue 587 * and complete the contents of the given ELF file. 588 */ 589 static int 590 dump_elf64(dtrace_hdl_t *dtp, const dof_hdr_t *dof, int fd) 591 { 592 struct { 593 Elf64_Ehdr ehdr; 594 Elf64_Shdr shdr[ESHDR_NUM]; 595 } elf_file; 596 597 Elf64_Shdr *shp; 598 Elf64_Off off; 599 dof_elf64_t de; 600 int ret = 0; 601 uint_t nshdr; 602 603 if (prepare_elf64(dtp, dof, &de) != 0) 604 return (-1); /* errno is set for us */ 605 606 /* 607 * If there are no relocations, we only need enough sections for 608 * the shstrtab and the DOF. 609 */ 610 nshdr = de.de_nrel == 0 ? ESHDR_SYMTAB + 1 : ESHDR_NUM; 611 612 bzero(&elf_file, sizeof (elf_file)); 613 614 elf_file.ehdr.e_ident[EI_MAG0] = ELFMAG0; 615 elf_file.ehdr.e_ident[EI_MAG1] = ELFMAG1; 616 elf_file.ehdr.e_ident[EI_MAG2] = ELFMAG2; 617 elf_file.ehdr.e_ident[EI_MAG3] = ELFMAG3; 618 elf_file.ehdr.e_ident[EI_VERSION] = EV_CURRENT; 619 elf_file.ehdr.e_ident[EI_CLASS] = ELFCLASS64; 620 #if defined(_BIG_ENDIAN) 621 elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2MSB; 622 #elif defined(_LITTLE_ENDIAN) 623 elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2LSB; 624 #endif 625 elf_file.ehdr.e_type = ET_REL; 626 #if defined(__sparc) 627 elf_file.ehdr.e_machine = EM_SPARCV9; 628 #elif defined(__i386) || defined(__amd64) 629 elf_file.ehdr.e_machine = EM_AMD64; 630 #endif 631 elf_file.ehdr.e_version = EV_CURRENT; 632 elf_file.ehdr.e_shoff = sizeof (Elf64_Ehdr); 633 elf_file.ehdr.e_ehsize = sizeof (Elf64_Ehdr); 634 elf_file.ehdr.e_phentsize = sizeof (Elf64_Phdr); 635 elf_file.ehdr.e_shentsize = sizeof (Elf64_Shdr); 636 elf_file.ehdr.e_shnum = nshdr; 637 elf_file.ehdr.e_shstrndx = ESHDR_SHSTRTAB; 638 off = sizeof (elf_file) + nshdr * sizeof (Elf64_Shdr); 639 640 shp = &elf_file.shdr[ESHDR_SHSTRTAB]; 641 shp->sh_name = 1; /* DTRACE_SHSTRTAB64[1] = ".shstrtab" */ 642 shp->sh_type = SHT_STRTAB; 643 shp->sh_offset = off; 644 shp->sh_size = sizeof (DTRACE_SHSTRTAB64); 645 shp->sh_addralign = sizeof (char); 646 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8); 647 648 shp = &elf_file.shdr[ESHDR_DOF]; 649 shp->sh_name = 11; /* DTRACE_SHSTRTAB64[11] = ".SUNW_dof" */ 650 shp->sh_flags = SHF_ALLOC; 651 shp->sh_type = SHT_SUNW_dof; 652 shp->sh_offset = off; 653 shp->sh_size = dof->dofh_filesz; 654 shp->sh_addralign = 8; 655 off = shp->sh_offset + shp->sh_size; 656 657 shp = &elf_file.shdr[ESHDR_STRTAB]; 658 shp->sh_name = 21; /* DTRACE_SHSTRTAB64[21] = ".strtab" */ 659 shp->sh_flags = SHF_ALLOC; 660 shp->sh_type = SHT_STRTAB; 661 shp->sh_offset = off; 662 shp->sh_size = de.de_strlen; 663 shp->sh_addralign = sizeof (char); 664 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8); 665 666 shp = &elf_file.shdr[ESHDR_SYMTAB]; 667 shp->sh_name = 29; /* DTRACE_SHSTRTAB64[29] = ".symtab" */ 668 shp->sh_flags = SHF_ALLOC; 669 shp->sh_type = SHT_SYMTAB; 670 shp->sh_entsize = sizeof (Elf64_Sym); 671 shp->sh_link = ESHDR_STRTAB; 672 shp->sh_offset = off; 673 shp->sh_info = de.de_global; 674 shp->sh_size = de.de_nsym * sizeof (Elf64_Sym); 675 shp->sh_addralign = 8; 676 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8); 677 678 if (de.de_nrel == 0) { 679 if (dt_write(dtp, fd, &elf_file, 680 sizeof (elf_file)) != sizeof (elf_file) || 681 PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB64) || 682 PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) || 683 PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) || 684 PWRITE_SCN(ESHDR_DOF, dof)) { 685 ret = dt_set_errno(dtp, errno); 686 } 687 } else { 688 shp = &elf_file.shdr[ESHDR_REL]; 689 shp->sh_name = 37; /* DTRACE_SHSTRTAB64[37] = ".rel.SUNW_dof" */ 690 shp->sh_flags = SHF_ALLOC; 691 shp->sh_type = SHT_RELA; 692 shp->sh_entsize = sizeof (de.de_rel[0]); 693 shp->sh_link = ESHDR_SYMTAB; 694 shp->sh_info = ESHDR_DOF; 695 shp->sh_offset = off; 696 shp->sh_size = de.de_nrel * sizeof (de.de_rel[0]); 697 shp->sh_addralign = 8; 698 699 if (dt_write(dtp, fd, &elf_file, 700 sizeof (elf_file)) != sizeof (elf_file) || 701 PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB64) || 702 PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) || 703 PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) || 704 PWRITE_SCN(ESHDR_REL, de.de_rel) || 705 PWRITE_SCN(ESHDR_DOF, dof)) { 706 ret = dt_set_errno(dtp, errno); 707 } 708 } 709 710 free(de.de_strtab); 711 free(de.de_sym); 712 free(de.de_rel); 713 714 return (ret); 715 } 716 717 static int 718 dt_symtab_lookup(Elf_Data *data_sym, int nsym, uintptr_t addr, uint_t shn, 719 GElf_Sym *sym) 720 { 721 int i, ret = -1; 722 GElf_Sym s; 723 724 for (i = 0; i < nsym && gelf_getsym(data_sym, i, sym) != NULL; i++) { 725 if (GELF_ST_TYPE(sym->st_info) == STT_FUNC && 726 shn == sym->st_shndx && 727 sym->st_value <= addr && 728 addr < sym->st_value + sym->st_size) { 729 if (GELF_ST_BIND(sym->st_info) == STB_GLOBAL) 730 return (0); 731 732 ret = 0; 733 s = *sym; 734 } 735 } 736 737 if (ret == 0) 738 *sym = s; 739 return (ret); 740 } 741 742 #if defined(__sparc) 743 744 #define DT_OP_RET 0x81c7e008 745 #define DT_OP_NOP 0x01000000 746 #define DT_OP_CALL 0x40000000 747 #define DT_OP_CLR_O0 0x90102000 748 749 #define DT_IS_MOV_O7(inst) (((inst) & 0xffffe000) == 0x9e100000) 750 #define DT_IS_RESTORE(inst) (((inst) & 0xc1f80000) == 0x81e80000) 751 #define DT_IS_RETL(inst) (((inst) & 0xfff83fff) == 0x81c02008) 752 753 #define DT_RS2(inst) ((inst) & 0x1f) 754 #define DT_MAKE_RETL(reg) (0x81c02008 | ((reg) << 14)) 755 756 /*ARGSUSED*/ 757 static int 758 dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela, 759 uint32_t *off) 760 { 761 uint32_t *ip; 762 763 if ((rela->r_offset & (sizeof (uint32_t) - 1)) != 0) 764 return (-1); 765 766 /*LINTED*/ 767 ip = (uint32_t *)(p + rela->r_offset); 768 769 /* 770 * We only know about some specific relocation types. 771 */ 772 if (GELF_R_TYPE(rela->r_info) != R_SPARC_WDISP30 && 773 GELF_R_TYPE(rela->r_info) != R_SPARC_WPLT30) 774 return (-1); 775 776 /* 777 * We may have already processed this object file in an earlier linker 778 * invocation. Check to see if the present instruction sequence matches 779 * the one we would install. 780 */ 781 if (isenabled) { 782 if (ip[0] == DT_OP_CLR_O0) 783 return (0); 784 } else { 785 if (DT_IS_RESTORE(ip[1])) { 786 if (ip[0] == DT_OP_RET) 787 return (0); 788 } else if (DT_IS_MOV_O7(ip[1])) { 789 if (DT_IS_RETL(ip[0])) 790 return (0); 791 } else { 792 if (ip[0] == DT_OP_NOP) { 793 (*off) += sizeof (ip[0]); 794 return (0); 795 } 796 } 797 } 798 799 /* 800 * We only expect call instructions with a displacement of 0. 801 */ 802 if (ip[0] != DT_OP_CALL) { 803 dt_dprintf("found %x instead of a call instruction at %llx\n", 804 ip[0], (u_longlong_t)rela->r_offset); 805 return (-1); 806 } 807 808 if (isenabled) { 809 /* 810 * It would necessarily indicate incorrect usage if an is- 811 * enabled probe were tail-called so flag that as an error. 812 * It's also potentially (very) tricky to handle gracefully, 813 * but could be done if this were a desired use scenario. 814 */ 815 if (DT_IS_RESTORE(ip[1]) || DT_IS_MOV_O7(ip[1])) { 816 dt_dprintf("tail call to is-enabled probe at %llx\n", 817 (u_longlong_t)rela->r_offset); 818 return (-1); 819 } 820 821 ip[0] = DT_OP_CLR_O0; 822 } else { 823 /* 824 * If the call is followed by a restore, it's a tail call so 825 * change the call to a ret. If the call if followed by a mov 826 * of a register into %o7, it's a tail call in leaf context 827 * so change the call to a retl-like instruction that returns 828 * to that register value + 8 (rather than the typical %o7 + 829 * 8). Otherwise we adjust the offset to land on what was 830 * once the delay slot of the call so we correctly get all 831 * the arguments. 832 */ 833 if (DT_IS_RESTORE(ip[1])) { 834 ip[0] = DT_OP_RET; 835 } else if (DT_IS_MOV_O7(ip[1])) { 836 ip[0] = DT_MAKE_RETL(DT_RS2(ip[1])); 837 } else { 838 ip[0] = DT_OP_NOP; 839 (*off) += sizeof (ip[0]); 840 } 841 } 842 843 return (0); 844 } 845 846 #elif defined(__i386) || defined(__amd64) 847 848 #define DT_OP_NOP 0x90 849 #define DT_OP_CALL 0xe8 850 #define DT_OP_REX_RAX 0x48 851 #define DT_OP_XOR_EAX_0 0x33 852 #define DT_OP_XOR_EAX_1 0xc0 853 854 static int 855 dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela, 856 uint32_t *off) 857 { 858 uint8_t *ip = (uint8_t *)(p + rela->r_offset - 1); 859 860 /* 861 * On x86, the first byte of the instruction is the call opcode and 862 * the next four bytes are the 32-bit address; the relocation is for 863 * the address operand. We back up the offset to the first byte of 864 * the instruction. For is-enabled probes, we later advance the offset 865 * so that it hits the first nop in the instruction sequence. 866 */ 867 (*off) -= 1; 868 869 /* 870 * We only know about some specific relocation types. Luckily 871 * these types have the same values on both 32-bit and 64-bit 872 * x86 architectures. 873 */ 874 if (GELF_R_TYPE(rela->r_info) != R_386_PC32 && 875 GELF_R_TYPE(rela->r_info) != R_386_PLT32) 876 return (-1); 877 878 /* 879 * We may have already processed this object file in an earlier linker 880 * invocation. Check to see if the present instruction sequence matches 881 * the one we would install. For is-enabled probes, we advance the 882 * offset to the first nop instruction in the sequence. 883 */ 884 if (!isenabled) { 885 if (ip[0] == DT_OP_NOP && ip[1] == DT_OP_NOP && 886 ip[2] == DT_OP_NOP && ip[3] == DT_OP_NOP && 887 ip[4] == DT_OP_NOP) 888 return (0); 889 } else if (dtp->dt_oflags & DTRACE_O_LP64) { 890 if (ip[0] == DT_OP_REX_RAX && 891 ip[1] == DT_OP_XOR_EAX_0 && ip[2] == DT_OP_XOR_EAX_1 && 892 ip[3] == DT_OP_NOP && ip[4] == DT_OP_NOP) { 893 (*off) += 3; 894 return (0); 895 } 896 } else { 897 if (ip[0] == DT_OP_XOR_EAX_0 && ip[1] == DT_OP_XOR_EAX_1 && 898 ip[2] == DT_OP_NOP && ip[3] == DT_OP_NOP && 899 ip[4] == DT_OP_NOP) { 900 (*off) += 2; 901 return (0); 902 } 903 } 904 905 /* 906 * We only expect a call instrution with a 32-bit displacement. 907 */ 908 if (ip[0] != DT_OP_CALL) { 909 dt_dprintf("found %x instead of a call instruction at %llx\n", 910 ip[0], (u_longlong_t)rela->r_offset); 911 return (-1); 912 } 913 914 /* 915 * Establish the instruction sequence -- all nops for probes, and an 916 * instruction to clear the return value register (%eax/%rax) followed 917 * by nops for is-enabled probes. For is-enabled probes, we advance 918 * the offset to the first nop. This isn't stricly necessary but makes 919 * for more readable disassembly when the probe is enabled. 920 */ 921 if (!isenabled) { 922 ip[0] = DT_OP_NOP; 923 ip[1] = DT_OP_NOP; 924 ip[2] = DT_OP_NOP; 925 ip[3] = DT_OP_NOP; 926 ip[4] = DT_OP_NOP; 927 } else if (dtp->dt_oflags & DTRACE_O_LP64) { 928 ip[0] = DT_OP_REX_RAX; 929 ip[1] = DT_OP_XOR_EAX_0; 930 ip[2] = DT_OP_XOR_EAX_1; 931 ip[3] = DT_OP_NOP; 932 ip[4] = DT_OP_NOP; 933 (*off) += 3; 934 } else { 935 ip[0] = DT_OP_XOR_EAX_0; 936 ip[1] = DT_OP_XOR_EAX_1; 937 ip[2] = DT_OP_NOP; 938 ip[3] = DT_OP_NOP; 939 ip[4] = DT_OP_NOP; 940 (*off) += 2; 941 } 942 943 return (0); 944 } 945 946 #else 947 #error unknown ISA 948 #endif 949 950 /*PRINTFLIKE5*/ 951 static int 952 dt_link_error(dtrace_hdl_t *dtp, Elf *elf, int fd, dt_link_pair_t *bufs, 953 const char *format, ...) 954 { 955 va_list ap; 956 dt_link_pair_t *pair; 957 958 va_start(ap, format); 959 dt_set_errmsg(dtp, NULL, NULL, NULL, 0, format, ap); 960 va_end(ap); 961 962 if (elf != NULL) 963 (void) elf_end(elf); 964 965 if (fd >= 0) 966 (void) close(fd); 967 968 while ((pair = bufs) != NULL) { 969 bufs = pair->dlp_next; 970 dt_free(dtp, pair->dlp_str); 971 dt_free(dtp, pair->dlp_sym); 972 dt_free(dtp, pair); 973 } 974 975 return (dt_set_errno(dtp, EDT_COMPILER)); 976 } 977 978 static int 979 process_obj(dtrace_hdl_t *dtp, const char *obj, int *eprobesp) 980 { 981 static const char dt_prefix[] = "__dtrace"; 982 static const char dt_enabled[] = "enabled"; 983 static const char dt_symprefix[] = "$dtrace"; 984 static const char dt_symfmt[] = "%s%d.%s"; 985 int fd, i, ndx, eprobe, mod = 0; 986 Elf *elf = NULL; 987 GElf_Ehdr ehdr; 988 Elf_Scn *scn_rel, *scn_sym, *scn_str, *scn_tgt; 989 Elf_Data *data_rel, *data_sym, *data_str, *data_tgt; 990 GElf_Shdr shdr_rel, shdr_sym, shdr_str, shdr_tgt; 991 GElf_Sym rsym, fsym, dsym; 992 GElf_Rela rela; 993 char *s, *p, *r; 994 char pname[DTRACE_PROVNAMELEN]; 995 dt_provider_t *pvp; 996 dt_probe_t *prp; 997 uint32_t off, eclass, emachine1, emachine2; 998 size_t symsize, nsym, isym, istr, len; 999 key_t objkey; 1000 dt_link_pair_t *pair, *bufs = NULL; 1001 dt_strtab_t *strtab; 1002 1003 if ((fd = open64(obj, O_RDWR)) == -1) { 1004 return (dt_link_error(dtp, elf, fd, bufs, 1005 "failed to open %s: %s", obj, strerror(errno))); 1006 } 1007 1008 if ((elf = elf_begin(fd, ELF_C_RDWR, NULL)) == NULL) { 1009 return (dt_link_error(dtp, elf, fd, bufs, 1010 "failed to process %s: %s", obj, elf_errmsg(elf_errno()))); 1011 } 1012 1013 switch (elf_kind(elf)) { 1014 case ELF_K_ELF: 1015 break; 1016 case ELF_K_AR: 1017 return (dt_link_error(dtp, elf, fd, bufs, "archives are not " 1018 "permitted; use the contents of the archive instead: %s", 1019 obj)); 1020 default: 1021 return (dt_link_error(dtp, elf, fd, bufs, 1022 "invalid file type: %s", obj)); 1023 } 1024 1025 if (gelf_getehdr(elf, &ehdr) == NULL) { 1026 return (dt_link_error(dtp, elf, fd, bufs, "corrupt file: %s", 1027 obj)); 1028 } 1029 1030 if (dtp->dt_oflags & DTRACE_O_LP64) { 1031 eclass = ELFCLASS64; 1032 #if defined(__sparc) 1033 emachine1 = emachine2 = EM_SPARCV9; 1034 #elif defined(__i386) || defined(__amd64) 1035 emachine1 = emachine2 = EM_AMD64; 1036 #endif 1037 symsize = sizeof (Elf64_Sym); 1038 } else { 1039 eclass = ELFCLASS32; 1040 #if defined(__sparc) 1041 emachine1 = EM_SPARC; 1042 emachine2 = EM_SPARC32PLUS; 1043 #elif defined(__i386) || defined(__amd64) 1044 emachine1 = emachine2 = EM_386; 1045 #endif 1046 symsize = sizeof (Elf32_Sym); 1047 } 1048 1049 if (ehdr.e_ident[EI_CLASS] != eclass) { 1050 return (dt_link_error(dtp, elf, fd, bufs, 1051 "incorrect ELF class for object file: %s", obj)); 1052 } 1053 1054 if (ehdr.e_machine != emachine1 && ehdr.e_machine != emachine2) { 1055 return (dt_link_error(dtp, elf, fd, bufs, 1056 "incorrect ELF machine type for object file: %s", obj)); 1057 } 1058 1059 /* 1060 * We use this token as a relatively unique handle for this file on the 1061 * system in order to disambiguate potential conflicts between files of 1062 * the same name which contain identially named local symbols. 1063 */ 1064 if ((objkey = ftok(obj, 0)) == (key_t)-1) { 1065 return (dt_link_error(dtp, elf, fd, bufs, 1066 "failed to generate unique key for object file: %s", obj)); 1067 } 1068 1069 scn_rel = NULL; 1070 while ((scn_rel = elf_nextscn(elf, scn_rel)) != NULL) { 1071 if (gelf_getshdr(scn_rel, &shdr_rel) == NULL) 1072 goto err; 1073 1074 /* 1075 * Skip any non-relocation sections. 1076 */ 1077 if (shdr_rel.sh_type != SHT_RELA && shdr_rel.sh_type != SHT_REL) 1078 continue; 1079 1080 if ((data_rel = elf_getdata(scn_rel, NULL)) == NULL) 1081 goto err; 1082 1083 /* 1084 * Grab the section, section header and section data for the 1085 * symbol table that this relocation section references. 1086 */ 1087 if ((scn_sym = elf_getscn(elf, shdr_rel.sh_link)) == NULL || 1088 gelf_getshdr(scn_sym, &shdr_sym) == NULL || 1089 (data_sym = elf_getdata(scn_sym, NULL)) == NULL) 1090 goto err; 1091 1092 /* 1093 * Ditto for that symbol table's string table. 1094 */ 1095 if ((scn_str = elf_getscn(elf, shdr_sym.sh_link)) == NULL || 1096 gelf_getshdr(scn_str, &shdr_str) == NULL || 1097 (data_str = elf_getdata(scn_str, NULL)) == NULL) 1098 goto err; 1099 1100 /* 1101 * Grab the section, section header and section data for the 1102 * target section for the relocations. For the relocations 1103 * we're looking for -- this will typically be the text of the 1104 * object file. 1105 */ 1106 if ((scn_tgt = elf_getscn(elf, shdr_rel.sh_info)) == NULL || 1107 gelf_getshdr(scn_tgt, &shdr_tgt) == NULL || 1108 (data_tgt = elf_getdata(scn_tgt, NULL)) == NULL) 1109 goto err; 1110 1111 /* 1112 * We're looking for relocations to symbols matching this form: 1113 * 1114 * __dtrace[enabled]_<prov>___<probe> 1115 * 1116 * For the generated object, we need to record the location 1117 * identified by the relocation, and create a new relocation 1118 * in the generated object that will be resolved at link time 1119 * to the location of the function in which the probe is 1120 * embedded. In the target object, we change the matched symbol 1121 * so that it will be ignored at link time, and we modify the 1122 * target (text) section to replace the call instruction with 1123 * one or more nops. 1124 * 1125 * If the function containing the probe is locally scoped 1126 * (static), we create an alias used by the relocation in the 1127 * generated object. The alias, a new symbol, will be global 1128 * (so that the relocation from the generated object can be 1129 * resolved), and hidden (so that it is converted to a local 1130 * symbol at link time). Such aliases have this form: 1131 * 1132 * $dtrace<key>.<function> 1133 * 1134 * We take a first pass through all the relocations to 1135 * populate our string table and count the number of extra 1136 * symbols we'll require. 1137 */ 1138 strtab = dt_strtab_create(1); 1139 nsym = 0; 1140 isym = data_sym->d_size / symsize; 1141 istr = data_str->d_size; 1142 1143 for (i = 0; i < shdr_rel.sh_size / shdr_rel.sh_entsize; i++) { 1144 1145 if (shdr_rel.sh_type == SHT_RELA) { 1146 if (gelf_getrela(data_rel, i, &rela) == NULL) 1147 continue; 1148 } else { 1149 GElf_Rel rel; 1150 if (gelf_getrel(data_rel, i, &rel) == NULL) 1151 continue; 1152 rela.r_offset = rel.r_offset; 1153 rela.r_info = rel.r_info; 1154 rela.r_addend = 0; 1155 } 1156 1157 if (gelf_getsym(data_sym, GELF_R_SYM(rela.r_info), 1158 &rsym) == NULL) { 1159 dt_strtab_destroy(strtab); 1160 goto err; 1161 } 1162 1163 s = (char *)data_str->d_buf + rsym.st_name; 1164 1165 if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0) 1166 continue; 1167 1168 if (dt_symtab_lookup(data_sym, isym, rela.r_offset, 1169 shdr_rel.sh_info, &fsym) != 0) { 1170 dt_strtab_destroy(strtab); 1171 goto err; 1172 } 1173 1174 if (GELF_ST_BIND(fsym.st_info) != STB_LOCAL) 1175 continue; 1176 1177 if (fsym.st_name > data_str->d_size) { 1178 dt_strtab_destroy(strtab); 1179 goto err; 1180 } 1181 1182 s = (char *)data_str->d_buf + fsym.st_name; 1183 1184 /* 1185 * If this symbol isn't of type function, we've really 1186 * driven off the rails or the object file is corrupt. 1187 */ 1188 if (GELF_ST_TYPE(fsym.st_info) != STT_FUNC) { 1189 dt_strtab_destroy(strtab); 1190 return (dt_link_error(dtp, elf, fd, bufs, 1191 "expected %s to be of type function", s)); 1192 } 1193 1194 len = snprintf(NULL, 0, dt_symfmt, dt_symprefix, 1195 objkey, s) + 1; 1196 if ((p = dt_alloc(dtp, len)) == NULL) { 1197 dt_strtab_destroy(strtab); 1198 goto err; 1199 } 1200 (void) snprintf(p, len, dt_symfmt, dt_symprefix, 1201 objkey, s); 1202 1203 if (dt_strtab_index(strtab, p) == -1) { 1204 nsym++; 1205 (void) dt_strtab_insert(strtab, p); 1206 } 1207 1208 dt_free(dtp, p); 1209 } 1210 1211 /* 1212 * If needed, allocate the additional space for the symbol 1213 * table and string table copying the old data into the new 1214 * buffers, and marking the buffers as dirty. We inject those 1215 * newly allocated buffers into the libelf data structures, but 1216 * are still responsible for freeing them once we're done with 1217 * the elf handle. 1218 */ 1219 if (nsym > 0) { 1220 /* 1221 * The first byte of the string table is reserved for 1222 * the \0 entry. 1223 */ 1224 len = dt_strtab_size(strtab) - 1; 1225 1226 assert(len > 0); 1227 assert(dt_strtab_index(strtab, "") == 0); 1228 1229 dt_strtab_destroy(strtab); 1230 1231 if ((pair = dt_alloc(dtp, sizeof (*pair))) == NULL) 1232 goto err; 1233 1234 if ((pair->dlp_str = dt_alloc(dtp, data_str->d_size + 1235 len)) == NULL) { 1236 dt_free(dtp, pair); 1237 goto err; 1238 } 1239 1240 if ((pair->dlp_sym = dt_alloc(dtp, data_sym->d_size + 1241 nsym * symsize)) == NULL) { 1242 dt_free(dtp, pair->dlp_str); 1243 dt_free(dtp, pair); 1244 goto err; 1245 } 1246 1247 pair->dlp_next = bufs; 1248 bufs = pair; 1249 1250 bcopy(data_str->d_buf, pair->dlp_str, data_str->d_size); 1251 data_str->d_buf = pair->dlp_str; 1252 data_str->d_size += len; 1253 (void) elf_flagdata(data_str, ELF_C_SET, ELF_F_DIRTY); 1254 1255 shdr_str.sh_size += len; 1256 (void) gelf_update_shdr(scn_str, &shdr_str); 1257 1258 bcopy(data_sym->d_buf, pair->dlp_sym, data_sym->d_size); 1259 data_sym->d_buf = pair->dlp_sym; 1260 data_sym->d_size += nsym * symsize; 1261 (void) elf_flagdata(data_sym, ELF_C_SET, ELF_F_DIRTY); 1262 1263 shdr_sym.sh_size += nsym * symsize; 1264 (void) gelf_update_shdr(scn_sym, &shdr_sym); 1265 1266 nsym += isym; 1267 } else { 1268 dt_strtab_destroy(strtab); 1269 } 1270 1271 /* 1272 * Now that the tables have been allocated, perform the 1273 * modifications described above. 1274 */ 1275 for (i = 0; i < shdr_rel.sh_size / shdr_rel.sh_entsize; i++) { 1276 1277 if (shdr_rel.sh_type == SHT_RELA) { 1278 if (gelf_getrela(data_rel, i, &rela) == NULL) 1279 continue; 1280 } else { 1281 GElf_Rel rel; 1282 if (gelf_getrel(data_rel, i, &rel) == NULL) 1283 continue; 1284 rela.r_offset = rel.r_offset; 1285 rela.r_info = rel.r_info; 1286 rela.r_addend = 0; 1287 } 1288 1289 ndx = GELF_R_SYM(rela.r_info); 1290 1291 if (gelf_getsym(data_sym, ndx, &rsym) == NULL || 1292 rsym.st_name > data_str->d_size) 1293 goto err; 1294 1295 s = (char *)data_str->d_buf + rsym.st_name; 1296 1297 if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0) 1298 continue; 1299 1300 s += sizeof (dt_prefix) - 1; 1301 1302 /* 1303 * Check to see if this is an 'is-enabled' check as 1304 * opposed to a normal probe. 1305 */ 1306 if (strncmp(s, dt_enabled, 1307 sizeof (dt_enabled) - 1) == 0) { 1308 s += sizeof (dt_enabled) - 1; 1309 eprobe = 1; 1310 *eprobesp = 1; 1311 dt_dprintf("is-enabled probe\n"); 1312 } else { 1313 eprobe = 0; 1314 dt_dprintf("normal probe\n"); 1315 } 1316 1317 if (*s++ != '_') 1318 goto err; 1319 1320 if ((p = strstr(s, "___")) == NULL || 1321 p - s >= sizeof (pname)) 1322 goto err; 1323 1324 bcopy(s, pname, p - s); 1325 pname[p - s] = '\0'; 1326 1327 p = strhyphenate(p + 3); /* strlen("___") */ 1328 1329 if (dt_symtab_lookup(data_sym, isym, rela.r_offset, 1330 shdr_rel.sh_info, &fsym) != 0) 1331 goto err; 1332 1333 if (fsym.st_name > data_str->d_size) 1334 goto err; 1335 1336 assert(GELF_ST_TYPE(fsym.st_info) == STT_FUNC); 1337 1338 /* 1339 * If a NULL relocation name is passed to 1340 * dt_probe_define(), the function name is used for the 1341 * relocation. The relocation needs to use a mangled 1342 * name if the symbol is locally scoped; the function 1343 * name may need to change if we've found the global 1344 * alias for the locally scoped symbol (we prefer 1345 * global symbols to locals in dt_symtab_lookup()). 1346 */ 1347 s = (char *)data_str->d_buf + fsym.st_name; 1348 r = NULL; 1349 1350 if (GELF_ST_BIND(fsym.st_info) == STB_LOCAL) { 1351 dsym = fsym; 1352 dsym.st_name = istr; 1353 dsym.st_info = GELF_ST_INFO(STB_GLOBAL, 1354 STT_FUNC); 1355 dsym.st_other = ELF64_ST_VISIBILITY(STV_HIDDEN); 1356 (void) gelf_update_sym(data_sym, isym, &dsym); 1357 1358 r = (char *)data_str->d_buf + istr; 1359 istr += 1 + sprintf(r, dt_symfmt, 1360 dt_symprefix, objkey, s); 1361 isym++; 1362 assert(isym <= nsym); 1363 1364 } else if (strncmp(s, dt_symprefix, 1365 strlen(dt_symprefix)) == 0) { 1366 r = s; 1367 if ((s = strchr(s, '.')) == NULL) 1368 goto err; 1369 s++; 1370 } 1371 1372 if ((pvp = dt_provider_lookup(dtp, pname)) == NULL) { 1373 return (dt_link_error(dtp, elf, fd, bufs, 1374 "no such provider %s", pname)); 1375 } 1376 1377 if ((prp = dt_probe_lookup(pvp, p)) == NULL) { 1378 return (dt_link_error(dtp, elf, fd, bufs, 1379 "no such probe %s", p)); 1380 } 1381 1382 assert(fsym.st_value <= rela.r_offset); 1383 1384 off = rela.r_offset - fsym.st_value; 1385 if (dt_modtext(dtp, data_tgt->d_buf, eprobe, 1386 &rela, &off) != 0) { 1387 goto err; 1388 } 1389 1390 if (dt_probe_define(pvp, prp, s, r, off, eprobe) != 0) { 1391 return (dt_link_error(dtp, elf, fd, bufs, 1392 "failed to allocate space for probe")); 1393 } 1394 1395 mod = 1; 1396 (void) elf_flagdata(data_tgt, ELF_C_SET, ELF_F_DIRTY); 1397 1398 /* 1399 * This symbol may already have been marked to 1400 * be ignored by another relocation referencing 1401 * the same symbol or if this object file has 1402 * already been processed by an earlier link 1403 * invocation. 1404 */ 1405 if (rsym.st_shndx != SHN_SUNW_IGNORE) { 1406 rsym.st_shndx = SHN_SUNW_IGNORE; 1407 (void) gelf_update_sym(data_sym, ndx, &rsym); 1408 } 1409 } 1410 } 1411 1412 if (mod && elf_update(elf, ELF_C_WRITE) == -1) 1413 goto err; 1414 1415 (void) elf_end(elf); 1416 (void) close(fd); 1417 1418 while ((pair = bufs) != NULL) { 1419 bufs = pair->dlp_next; 1420 dt_free(dtp, pair->dlp_str); 1421 dt_free(dtp, pair->dlp_sym); 1422 dt_free(dtp, pair); 1423 } 1424 1425 return (0); 1426 1427 err: 1428 return (dt_link_error(dtp, elf, fd, bufs, 1429 "an error was encountered while processing %s", obj)); 1430 } 1431 1432 int 1433 dtrace_program_link(dtrace_hdl_t *dtp, dtrace_prog_t *pgp, uint_t dflags, 1434 const char *file, int objc, char *const objv[]) 1435 { 1436 char drti[PATH_MAX]; 1437 dof_hdr_t *dof; 1438 int fd, status, i, cur; 1439 char *cmd, tmp; 1440 size_t len; 1441 int eprobes = 0, ret = 0; 1442 1443 /* 1444 * A NULL program indicates a special use in which we just link 1445 * together a bunch of object files specified in objv and then 1446 * unlink(2) those object files. 1447 */ 1448 if (pgp == NULL) { 1449 const char *fmt = "%s -o %s -r"; 1450 1451 len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file) + 1; 1452 1453 for (i = 0; i < objc; i++) 1454 len += strlen(objv[i]) + 1; 1455 1456 cmd = alloca(len); 1457 1458 cur = snprintf(cmd, len, fmt, dtp->dt_ld_path, file); 1459 1460 for (i = 0; i < objc; i++) 1461 cur += snprintf(cmd + cur, len - cur, " %s", objv[i]); 1462 1463 if ((status = system(cmd)) == -1) { 1464 return (dt_link_error(dtp, NULL, -1, NULL, 1465 "failed to run %s: %s", dtp->dt_ld_path, 1466 strerror(errno))); 1467 } 1468 1469 if (WIFSIGNALED(status)) { 1470 return (dt_link_error(dtp, NULL, -1, NULL, 1471 "failed to link %s: %s failed due to signal %d", 1472 file, dtp->dt_ld_path, WTERMSIG(status))); 1473 } 1474 1475 if (WEXITSTATUS(status) != 0) { 1476 return (dt_link_error(dtp, NULL, -1, NULL, 1477 "failed to link %s: %s exited with status %d\n", 1478 file, dtp->dt_ld_path, WEXITSTATUS(status))); 1479 } 1480 1481 for (i = 0; i < objc; i++) { 1482 if (strcmp(objv[i], file) != 0) 1483 (void) unlink(objv[i]); 1484 } 1485 1486 return (0); 1487 } 1488 1489 for (i = 0; i < objc; i++) { 1490 if (process_obj(dtp, objv[i], &eprobes) != 0) 1491 return (-1); /* errno is set for us */ 1492 } 1493 1494 /* 1495 * If there are is-enabled probes then we need to force use of DOF 1496 * version 2. 1497 */ 1498 if (eprobes && pgp->dp_dofversion < DOF_VERSION_2) 1499 pgp->dp_dofversion = DOF_VERSION_2; 1500 1501 if ((dof = dtrace_dof_create(dtp, pgp, dflags)) == NULL) 1502 return (-1); /* errno is set for us */ 1503 1504 /* 1505 * Create a temporary file and then unlink it if we're going to 1506 * combine it with drti.o later. We can still refer to it in child 1507 * processes as /dev/fd/<fd>. 1508 */ 1509 if ((fd = open64(file, O_RDWR | O_CREAT | O_TRUNC, 0666)) == -1) { 1510 return (dt_link_error(dtp, NULL, -1, NULL, 1511 "failed to open %s: %s", file, strerror(errno))); 1512 } 1513 1514 /* 1515 * If -xlinktype=DOF has been selected, just write out the DOF. 1516 * Otherwise proceed to the default of generating and linking ELF. 1517 */ 1518 switch (dtp->dt_linktype) { 1519 case DT_LTYP_DOF: 1520 if (dt_write(dtp, fd, dof, dof->dofh_filesz) < dof->dofh_filesz) 1521 ret = errno; 1522 1523 if (close(fd) != 0 && ret == 0) 1524 ret = errno; 1525 1526 if (ret != 0) { 1527 return (dt_link_error(dtp, NULL, -1, NULL, 1528 "failed to write %s: %s", file, strerror(ret))); 1529 } 1530 1531 return (0); 1532 1533 case DT_LTYP_ELF: 1534 break; /* fall through to the rest of dtrace_program_link() */ 1535 1536 default: 1537 return (dt_link_error(dtp, NULL, -1, NULL, 1538 "invalid link type %u\n", dtp->dt_linktype)); 1539 } 1540 1541 1542 if (!dtp->dt_lazyload) 1543 (void) unlink(file); 1544 1545 if (dtp->dt_oflags & DTRACE_O_LP64) 1546 status = dump_elf64(dtp, dof, fd); 1547 else 1548 status = dump_elf32(dtp, dof, fd); 1549 1550 if (status != 0 || lseek(fd, 0, SEEK_SET) != 0) { 1551 return (dt_link_error(dtp, NULL, -1, NULL, 1552 "failed to write %s: %s", file, strerror(errno))); 1553 } 1554 1555 if (!dtp->dt_lazyload) { 1556 const char *fmt = "%s -o %s -r -Blocal -Breduce /dev/fd/%d %s"; 1557 1558 if (dtp->dt_oflags & DTRACE_O_LP64) { 1559 (void) snprintf(drti, sizeof (drti), 1560 "%s/64/drti.o", _dtrace_libdir); 1561 } else { 1562 (void) snprintf(drti, sizeof (drti), 1563 "%s/drti.o", _dtrace_libdir); 1564 } 1565 1566 len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file, fd, 1567 drti) + 1; 1568 1569 cmd = alloca(len); 1570 1571 (void) snprintf(cmd, len, fmt, dtp->dt_ld_path, file, fd, drti); 1572 1573 if ((status = system(cmd)) == -1) { 1574 ret = dt_link_error(dtp, NULL, -1, NULL, 1575 "failed to run %s: %s", dtp->dt_ld_path, 1576 strerror(errno)); 1577 goto done; 1578 } 1579 1580 (void) close(fd); /* release temporary file */ 1581 1582 if (WIFSIGNALED(status)) { 1583 ret = dt_link_error(dtp, NULL, -1, NULL, 1584 "failed to link %s: %s failed due to signal %d", 1585 file, dtp->dt_ld_path, WTERMSIG(status)); 1586 goto done; 1587 } 1588 1589 if (WEXITSTATUS(status) != 0) { 1590 ret = dt_link_error(dtp, NULL, -1, NULL, 1591 "failed to link %s: %s exited with status %d\n", 1592 file, dtp->dt_ld_path, WEXITSTATUS(status)); 1593 goto done; 1594 } 1595 } else { 1596 (void) close(fd); 1597 } 1598 1599 done: 1600 dtrace_dof_destroy(dtp, dof); 1601 return (ret); 1602 } 1603