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 2008 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 below. 780 */ 781 if (isenabled) { 782 if (ip[0] == DT_OP_NOP) { 783 (*off) += sizeof (ip[0]); 784 return (0); 785 } 786 } else { 787 if (DT_IS_RESTORE(ip[1])) { 788 if (ip[0] == DT_OP_RET) { 789 (*off) += sizeof (ip[0]); 790 return (0); 791 } 792 } else if (DT_IS_MOV_O7(ip[1])) { 793 if (DT_IS_RETL(ip[0])) 794 return (0); 795 } else { 796 if (ip[0] == DT_OP_NOP) { 797 (*off) += sizeof (ip[0]); 798 return (0); 799 } 800 } 801 } 802 803 /* 804 * We only expect call instructions with a displacement of 0. 805 */ 806 if (ip[0] != DT_OP_CALL) { 807 dt_dprintf("found %x instead of a call instruction at %llx\n", 808 ip[0], (u_longlong_t)rela->r_offset); 809 return (-1); 810 } 811 812 if (isenabled) { 813 /* 814 * It would necessarily indicate incorrect usage if an is- 815 * enabled probe were tail-called so flag that as an error. 816 * It's also potentially (very) tricky to handle gracefully, 817 * but could be done if this were a desired use scenario. 818 */ 819 if (DT_IS_RESTORE(ip[1]) || DT_IS_MOV_O7(ip[1])) { 820 dt_dprintf("tail call to is-enabled probe at %llx\n", 821 (u_longlong_t)rela->r_offset); 822 return (-1); 823 } 824 825 826 /* 827 * On SPARC, we take advantage of the fact that the first 828 * argument shares the same register as for the return value. 829 * The macro handles the work of zeroing that register so we 830 * don't need to do anything special here. We instrument the 831 * instruction in the delay slot as we'll need to modify the 832 * return register after that instruction has been emulated. 833 */ 834 ip[0] = DT_OP_NOP; 835 (*off) += sizeof (ip[0]); 836 } else { 837 /* 838 * If the call is followed by a restore, it's a tail call so 839 * change the call to a ret. If the call if followed by a mov 840 * of a register into %o7, it's a tail call in leaf context 841 * so change the call to a retl-like instruction that returns 842 * to that register value + 8 (rather than the typical %o7 + 843 * 8); the delay slot instruction is left, but should have no 844 * effect. Otherwise we change the call to be a nop. We 845 * identify the subsequent instruction as the probe point in 846 * all but the leaf tail-call case to ensure that arguments to 847 * the probe are complete and consistent. An astute, though 848 * largely hypothetical, observer would note that there is the 849 * possibility of a false-positive probe firing if the function 850 * contained a branch to the instruction in the delay slot of 851 * the call. Fixing this would require significant in-kernel 852 * modifications, and isn't worth doing until we see it in the 853 * wild. 854 */ 855 if (DT_IS_RESTORE(ip[1])) { 856 ip[0] = DT_OP_RET; 857 (*off) += sizeof (ip[0]); 858 } else if (DT_IS_MOV_O7(ip[1])) { 859 ip[0] = DT_MAKE_RETL(DT_RS2(ip[1])); 860 } else { 861 ip[0] = DT_OP_NOP; 862 (*off) += sizeof (ip[0]); 863 } 864 } 865 866 return (0); 867 } 868 869 #elif defined(__i386) || defined(__amd64) 870 871 #define DT_OP_NOP 0x90 872 #define DT_OP_RET 0xc3 873 #define DT_OP_CALL 0xe8 874 #define DT_OP_JMP32 0xe9 875 #define DT_OP_REX_RAX 0x48 876 #define DT_OP_XOR_EAX_0 0x33 877 #define DT_OP_XOR_EAX_1 0xc0 878 879 static int 880 dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela, 881 uint32_t *off) 882 { 883 uint8_t *ip = (uint8_t *)(p + rela->r_offset - 1); 884 uint8_t ret; 885 886 /* 887 * On x86, the first byte of the instruction is the call opcode and 888 * the next four bytes are the 32-bit address; the relocation is for 889 * the address operand. We back up the offset to the first byte of 890 * the instruction. For is-enabled probes, we later advance the offset 891 * so that it hits the first nop in the instruction sequence. 892 */ 893 (*off) -= 1; 894 895 /* 896 * We only know about some specific relocation types. Luckily 897 * these types have the same values on both 32-bit and 64-bit 898 * x86 architectures. 899 */ 900 if (GELF_R_TYPE(rela->r_info) != R_386_PC32 && 901 GELF_R_TYPE(rela->r_info) != R_386_PLT32) 902 return (-1); 903 904 /* 905 * We may have already processed this object file in an earlier linker 906 * invocation. Check to see if the present instruction sequence matches 907 * the one we would install. For is-enabled probes, we advance the 908 * offset to the first nop instruction in the sequence to match the 909 * text modification code below. 910 */ 911 if (!isenabled) { 912 if ((ip[0] == DT_OP_NOP || ip[0] == DT_OP_RET) && 913 ip[1] == DT_OP_NOP && ip[2] == DT_OP_NOP && 914 ip[3] == DT_OP_NOP && ip[4] == DT_OP_NOP) 915 return (0); 916 } else if (dtp->dt_oflags & DTRACE_O_LP64) { 917 if (ip[0] == DT_OP_REX_RAX && 918 ip[1] == DT_OP_XOR_EAX_0 && ip[2] == DT_OP_XOR_EAX_1 && 919 (ip[3] == DT_OP_NOP || ip[3] == DT_OP_RET) && 920 ip[4] == DT_OP_NOP) { 921 (*off) += 3; 922 return (0); 923 } 924 } else { 925 if (ip[0] == DT_OP_XOR_EAX_0 && ip[1] == DT_OP_XOR_EAX_1 && 926 (ip[2] == DT_OP_NOP || ip[2] == DT_OP_RET) && 927 ip[3] == DT_OP_NOP && ip[4] == DT_OP_NOP) { 928 (*off) += 2; 929 return (0); 930 } 931 } 932 933 /* 934 * We expect either a call instrution with a 32-bit displacement or a 935 * jmp instruction with a 32-bit displacement acting as a tail-call. 936 */ 937 if (ip[0] != DT_OP_CALL && ip[0] != DT_OP_JMP32) { 938 dt_dprintf("found %x instead of a call or jmp instruction at " 939 "%llx\n", ip[0], (u_longlong_t)rela->r_offset); 940 return (-1); 941 } 942 943 ret = (ip[0] == DT_OP_JMP32) ? DT_OP_RET : DT_OP_NOP; 944 945 /* 946 * Establish the instruction sequence -- all nops for probes, and an 947 * instruction to clear the return value register (%eax/%rax) followed 948 * by nops for is-enabled probes. For is-enabled probes, we advance 949 * the offset to the first nop. This isn't stricly necessary but makes 950 * for more readable disassembly when the probe is enabled. 951 */ 952 if (!isenabled) { 953 ip[0] = ret; 954 ip[1] = DT_OP_NOP; 955 ip[2] = DT_OP_NOP; 956 ip[3] = DT_OP_NOP; 957 ip[4] = DT_OP_NOP; 958 } else if (dtp->dt_oflags & DTRACE_O_LP64) { 959 ip[0] = DT_OP_REX_RAX; 960 ip[1] = DT_OP_XOR_EAX_0; 961 ip[2] = DT_OP_XOR_EAX_1; 962 ip[3] = ret; 963 ip[4] = DT_OP_NOP; 964 (*off) += 3; 965 } else { 966 ip[0] = DT_OP_XOR_EAX_0; 967 ip[1] = DT_OP_XOR_EAX_1; 968 ip[2] = ret; 969 ip[3] = DT_OP_NOP; 970 ip[4] = DT_OP_NOP; 971 (*off) += 2; 972 } 973 974 return (0); 975 } 976 977 #else 978 #error unknown ISA 979 #endif 980 981 /*PRINTFLIKE5*/ 982 static int 983 dt_link_error(dtrace_hdl_t *dtp, Elf *elf, int fd, dt_link_pair_t *bufs, 984 const char *format, ...) 985 { 986 va_list ap; 987 dt_link_pair_t *pair; 988 989 va_start(ap, format); 990 dt_set_errmsg(dtp, NULL, NULL, NULL, 0, format, ap); 991 va_end(ap); 992 993 if (elf != NULL) 994 (void) elf_end(elf); 995 996 if (fd >= 0) 997 (void) close(fd); 998 999 while ((pair = bufs) != NULL) { 1000 bufs = pair->dlp_next; 1001 dt_free(dtp, pair->dlp_str); 1002 dt_free(dtp, pair->dlp_sym); 1003 dt_free(dtp, pair); 1004 } 1005 1006 return (dt_set_errno(dtp, EDT_COMPILER)); 1007 } 1008 1009 static int 1010 process_obj(dtrace_hdl_t *dtp, const char *obj, int *eprobesp) 1011 { 1012 static const char dt_prefix[] = "__dtrace"; 1013 static const char dt_enabled[] = "enabled"; 1014 static const char dt_symprefix[] = "$dtrace"; 1015 static const char dt_symfmt[] = "%s%d.%s"; 1016 int fd, i, ndx, eprobe, mod = 0; 1017 Elf *elf = NULL; 1018 GElf_Ehdr ehdr; 1019 Elf_Scn *scn_rel, *scn_sym, *scn_str, *scn_tgt; 1020 Elf_Data *data_rel, *data_sym, *data_str, *data_tgt; 1021 GElf_Shdr shdr_rel, shdr_sym, shdr_str, shdr_tgt; 1022 GElf_Sym rsym, fsym, dsym; 1023 GElf_Rela rela; 1024 char *s, *p, *r; 1025 char pname[DTRACE_PROVNAMELEN]; 1026 dt_provider_t *pvp; 1027 dt_probe_t *prp; 1028 uint32_t off, eclass, emachine1, emachine2; 1029 size_t symsize, nsym, isym, istr, len; 1030 key_t objkey; 1031 dt_link_pair_t *pair, *bufs = NULL; 1032 dt_strtab_t *strtab; 1033 1034 if ((fd = open64(obj, O_RDWR)) == -1) { 1035 return (dt_link_error(dtp, elf, fd, bufs, 1036 "failed to open %s: %s", obj, strerror(errno))); 1037 } 1038 1039 if ((elf = elf_begin(fd, ELF_C_RDWR, NULL)) == NULL) { 1040 return (dt_link_error(dtp, elf, fd, bufs, 1041 "failed to process %s: %s", obj, elf_errmsg(elf_errno()))); 1042 } 1043 1044 switch (elf_kind(elf)) { 1045 case ELF_K_ELF: 1046 break; 1047 case ELF_K_AR: 1048 return (dt_link_error(dtp, elf, fd, bufs, "archives are not " 1049 "permitted; use the contents of the archive instead: %s", 1050 obj)); 1051 default: 1052 return (dt_link_error(dtp, elf, fd, bufs, 1053 "invalid file type: %s", obj)); 1054 } 1055 1056 if (gelf_getehdr(elf, &ehdr) == NULL) { 1057 return (dt_link_error(dtp, elf, fd, bufs, "corrupt file: %s", 1058 obj)); 1059 } 1060 1061 if (dtp->dt_oflags & DTRACE_O_LP64) { 1062 eclass = ELFCLASS64; 1063 #if defined(__sparc) 1064 emachine1 = emachine2 = EM_SPARCV9; 1065 #elif defined(__i386) || defined(__amd64) 1066 emachine1 = emachine2 = EM_AMD64; 1067 #endif 1068 symsize = sizeof (Elf64_Sym); 1069 } else { 1070 eclass = ELFCLASS32; 1071 #if defined(__sparc) 1072 emachine1 = EM_SPARC; 1073 emachine2 = EM_SPARC32PLUS; 1074 #elif defined(__i386) || defined(__amd64) 1075 emachine1 = emachine2 = EM_386; 1076 #endif 1077 symsize = sizeof (Elf32_Sym); 1078 } 1079 1080 if (ehdr.e_ident[EI_CLASS] != eclass) { 1081 return (dt_link_error(dtp, elf, fd, bufs, 1082 "incorrect ELF class for object file: %s", obj)); 1083 } 1084 1085 if (ehdr.e_machine != emachine1 && ehdr.e_machine != emachine2) { 1086 return (dt_link_error(dtp, elf, fd, bufs, 1087 "incorrect ELF machine type for object file: %s", obj)); 1088 } 1089 1090 /* 1091 * We use this token as a relatively unique handle for this file on the 1092 * system in order to disambiguate potential conflicts between files of 1093 * the same name which contain identially named local symbols. 1094 */ 1095 if ((objkey = ftok(obj, 0)) == (key_t)-1) { 1096 return (dt_link_error(dtp, elf, fd, bufs, 1097 "failed to generate unique key for object file: %s", obj)); 1098 } 1099 1100 scn_rel = NULL; 1101 while ((scn_rel = elf_nextscn(elf, scn_rel)) != NULL) { 1102 if (gelf_getshdr(scn_rel, &shdr_rel) == NULL) 1103 goto err; 1104 1105 /* 1106 * Skip any non-relocation sections. 1107 */ 1108 if (shdr_rel.sh_type != SHT_RELA && shdr_rel.sh_type != SHT_REL) 1109 continue; 1110 1111 if ((data_rel = elf_getdata(scn_rel, NULL)) == NULL) 1112 goto err; 1113 1114 /* 1115 * Grab the section, section header and section data for the 1116 * symbol table that this relocation section references. 1117 */ 1118 if ((scn_sym = elf_getscn(elf, shdr_rel.sh_link)) == NULL || 1119 gelf_getshdr(scn_sym, &shdr_sym) == NULL || 1120 (data_sym = elf_getdata(scn_sym, NULL)) == NULL) 1121 goto err; 1122 1123 /* 1124 * Ditto for that symbol table's string table. 1125 */ 1126 if ((scn_str = elf_getscn(elf, shdr_sym.sh_link)) == NULL || 1127 gelf_getshdr(scn_str, &shdr_str) == NULL || 1128 (data_str = elf_getdata(scn_str, NULL)) == NULL) 1129 goto err; 1130 1131 /* 1132 * Grab the section, section header and section data for the 1133 * target section for the relocations. For the relocations 1134 * we're looking for -- this will typically be the text of the 1135 * object file. 1136 */ 1137 if ((scn_tgt = elf_getscn(elf, shdr_rel.sh_info)) == NULL || 1138 gelf_getshdr(scn_tgt, &shdr_tgt) == NULL || 1139 (data_tgt = elf_getdata(scn_tgt, NULL)) == NULL) 1140 goto err; 1141 1142 /* 1143 * We're looking for relocations to symbols matching this form: 1144 * 1145 * __dtrace[enabled]_<prov>___<probe> 1146 * 1147 * For the generated object, we need to record the location 1148 * identified by the relocation, and create a new relocation 1149 * in the generated object that will be resolved at link time 1150 * to the location of the function in which the probe is 1151 * embedded. In the target object, we change the matched symbol 1152 * so that it will be ignored at link time, and we modify the 1153 * target (text) section to replace the call instruction with 1154 * one or more nops. 1155 * 1156 * If the function containing the probe is locally scoped 1157 * (static), we create an alias used by the relocation in the 1158 * generated object. The alias, a new symbol, will be global 1159 * (so that the relocation from the generated object can be 1160 * resolved), and hidden (so that it is converted to a local 1161 * symbol at link time). Such aliases have this form: 1162 * 1163 * $dtrace<key>.<function> 1164 * 1165 * We take a first pass through all the relocations to 1166 * populate our string table and count the number of extra 1167 * symbols we'll require. 1168 */ 1169 strtab = dt_strtab_create(1); 1170 nsym = 0; 1171 isym = data_sym->d_size / symsize; 1172 istr = data_str->d_size; 1173 1174 for (i = 0; i < shdr_rel.sh_size / shdr_rel.sh_entsize; i++) { 1175 1176 if (shdr_rel.sh_type == SHT_RELA) { 1177 if (gelf_getrela(data_rel, i, &rela) == NULL) 1178 continue; 1179 } else { 1180 GElf_Rel rel; 1181 if (gelf_getrel(data_rel, i, &rel) == NULL) 1182 continue; 1183 rela.r_offset = rel.r_offset; 1184 rela.r_info = rel.r_info; 1185 rela.r_addend = 0; 1186 } 1187 1188 if (gelf_getsym(data_sym, GELF_R_SYM(rela.r_info), 1189 &rsym) == NULL) { 1190 dt_strtab_destroy(strtab); 1191 goto err; 1192 } 1193 1194 s = (char *)data_str->d_buf + rsym.st_name; 1195 1196 if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0) 1197 continue; 1198 1199 if (dt_symtab_lookup(data_sym, isym, rela.r_offset, 1200 shdr_rel.sh_info, &fsym) != 0) { 1201 dt_strtab_destroy(strtab); 1202 goto err; 1203 } 1204 1205 if (GELF_ST_BIND(fsym.st_info) != STB_LOCAL) 1206 continue; 1207 1208 if (fsym.st_name > data_str->d_size) { 1209 dt_strtab_destroy(strtab); 1210 goto err; 1211 } 1212 1213 s = (char *)data_str->d_buf + fsym.st_name; 1214 1215 /* 1216 * If this symbol isn't of type function, we've really 1217 * driven off the rails or the object file is corrupt. 1218 */ 1219 if (GELF_ST_TYPE(fsym.st_info) != STT_FUNC) { 1220 dt_strtab_destroy(strtab); 1221 return (dt_link_error(dtp, elf, fd, bufs, 1222 "expected %s to be of type function", s)); 1223 } 1224 1225 len = snprintf(NULL, 0, dt_symfmt, dt_symprefix, 1226 objkey, s) + 1; 1227 if ((p = dt_alloc(dtp, len)) == NULL) { 1228 dt_strtab_destroy(strtab); 1229 goto err; 1230 } 1231 (void) snprintf(p, len, dt_symfmt, dt_symprefix, 1232 objkey, s); 1233 1234 if (dt_strtab_index(strtab, p) == -1) { 1235 nsym++; 1236 (void) dt_strtab_insert(strtab, p); 1237 } 1238 1239 dt_free(dtp, p); 1240 } 1241 1242 /* 1243 * If needed, allocate the additional space for the symbol 1244 * table and string table copying the old data into the new 1245 * buffers, and marking the buffers as dirty. We inject those 1246 * newly allocated buffers into the libelf data structures, but 1247 * are still responsible for freeing them once we're done with 1248 * the elf handle. 1249 */ 1250 if (nsym > 0) { 1251 /* 1252 * The first byte of the string table is reserved for 1253 * the \0 entry. 1254 */ 1255 len = dt_strtab_size(strtab) - 1; 1256 1257 assert(len > 0); 1258 assert(dt_strtab_index(strtab, "") == 0); 1259 1260 dt_strtab_destroy(strtab); 1261 1262 if ((pair = dt_alloc(dtp, sizeof (*pair))) == NULL) 1263 goto err; 1264 1265 if ((pair->dlp_str = dt_alloc(dtp, data_str->d_size + 1266 len)) == NULL) { 1267 dt_free(dtp, pair); 1268 goto err; 1269 } 1270 1271 if ((pair->dlp_sym = dt_alloc(dtp, data_sym->d_size + 1272 nsym * symsize)) == NULL) { 1273 dt_free(dtp, pair->dlp_str); 1274 dt_free(dtp, pair); 1275 goto err; 1276 } 1277 1278 pair->dlp_next = bufs; 1279 bufs = pair; 1280 1281 bcopy(data_str->d_buf, pair->dlp_str, data_str->d_size); 1282 data_str->d_buf = pair->dlp_str; 1283 data_str->d_size += len; 1284 (void) elf_flagdata(data_str, ELF_C_SET, ELF_F_DIRTY); 1285 1286 shdr_str.sh_size += len; 1287 (void) gelf_update_shdr(scn_str, &shdr_str); 1288 1289 bcopy(data_sym->d_buf, pair->dlp_sym, data_sym->d_size); 1290 data_sym->d_buf = pair->dlp_sym; 1291 data_sym->d_size += nsym * symsize; 1292 (void) elf_flagdata(data_sym, ELF_C_SET, ELF_F_DIRTY); 1293 1294 shdr_sym.sh_size += nsym * symsize; 1295 (void) gelf_update_shdr(scn_sym, &shdr_sym); 1296 1297 nsym += isym; 1298 } else { 1299 dt_strtab_destroy(strtab); 1300 } 1301 1302 /* 1303 * Now that the tables have been allocated, perform the 1304 * modifications described above. 1305 */ 1306 for (i = 0; i < shdr_rel.sh_size / shdr_rel.sh_entsize; i++) { 1307 1308 if (shdr_rel.sh_type == SHT_RELA) { 1309 if (gelf_getrela(data_rel, i, &rela) == NULL) 1310 continue; 1311 } else { 1312 GElf_Rel rel; 1313 if (gelf_getrel(data_rel, i, &rel) == NULL) 1314 continue; 1315 rela.r_offset = rel.r_offset; 1316 rela.r_info = rel.r_info; 1317 rela.r_addend = 0; 1318 } 1319 1320 ndx = GELF_R_SYM(rela.r_info); 1321 1322 if (gelf_getsym(data_sym, ndx, &rsym) == NULL || 1323 rsym.st_name > data_str->d_size) 1324 goto err; 1325 1326 s = (char *)data_str->d_buf + rsym.st_name; 1327 1328 if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0) 1329 continue; 1330 1331 s += sizeof (dt_prefix) - 1; 1332 1333 /* 1334 * Check to see if this is an 'is-enabled' check as 1335 * opposed to a normal probe. 1336 */ 1337 if (strncmp(s, dt_enabled, 1338 sizeof (dt_enabled) - 1) == 0) { 1339 s += sizeof (dt_enabled) - 1; 1340 eprobe = 1; 1341 *eprobesp = 1; 1342 dt_dprintf("is-enabled probe\n"); 1343 } else { 1344 eprobe = 0; 1345 dt_dprintf("normal probe\n"); 1346 } 1347 1348 if (*s++ != '_') 1349 goto err; 1350 1351 if ((p = strstr(s, "___")) == NULL || 1352 p - s >= sizeof (pname)) 1353 goto err; 1354 1355 bcopy(s, pname, p - s); 1356 pname[p - s] = '\0'; 1357 1358 p = strhyphenate(p + 3); /* strlen("___") */ 1359 1360 if (dt_symtab_lookup(data_sym, isym, rela.r_offset, 1361 shdr_rel.sh_info, &fsym) != 0) 1362 goto err; 1363 1364 if (fsym.st_name > data_str->d_size) 1365 goto err; 1366 1367 assert(GELF_ST_TYPE(fsym.st_info) == STT_FUNC); 1368 1369 /* 1370 * If a NULL relocation name is passed to 1371 * dt_probe_define(), the function name is used for the 1372 * relocation. The relocation needs to use a mangled 1373 * name if the symbol is locally scoped; the function 1374 * name may need to change if we've found the global 1375 * alias for the locally scoped symbol (we prefer 1376 * global symbols to locals in dt_symtab_lookup()). 1377 */ 1378 s = (char *)data_str->d_buf + fsym.st_name; 1379 r = NULL; 1380 1381 if (GELF_ST_BIND(fsym.st_info) == STB_LOCAL) { 1382 dsym = fsym; 1383 dsym.st_name = istr; 1384 dsym.st_info = GELF_ST_INFO(STB_GLOBAL, 1385 STT_FUNC); 1386 dsym.st_other = 1387 ELF64_ST_VISIBILITY(STV_ELIMINATE); 1388 (void) gelf_update_sym(data_sym, isym, &dsym); 1389 1390 r = (char *)data_str->d_buf + istr; 1391 istr += 1 + sprintf(r, dt_symfmt, 1392 dt_symprefix, objkey, s); 1393 isym++; 1394 assert(isym <= nsym); 1395 1396 } else if (strncmp(s, dt_symprefix, 1397 strlen(dt_symprefix)) == 0) { 1398 r = s; 1399 if ((s = strchr(s, '.')) == NULL) 1400 goto err; 1401 s++; 1402 } 1403 1404 if ((pvp = dt_provider_lookup(dtp, pname)) == NULL) { 1405 return (dt_link_error(dtp, elf, fd, bufs, 1406 "no such provider %s", pname)); 1407 } 1408 1409 if ((prp = dt_probe_lookup(pvp, p)) == NULL) { 1410 return (dt_link_error(dtp, elf, fd, bufs, 1411 "no such probe %s", p)); 1412 } 1413 1414 assert(fsym.st_value <= rela.r_offset); 1415 1416 off = rela.r_offset - fsym.st_value; 1417 if (dt_modtext(dtp, data_tgt->d_buf, eprobe, 1418 &rela, &off) != 0) { 1419 goto err; 1420 } 1421 1422 if (dt_probe_define(pvp, prp, s, r, off, eprobe) != 0) { 1423 return (dt_link_error(dtp, elf, fd, bufs, 1424 "failed to allocate space for probe")); 1425 } 1426 1427 mod = 1; 1428 (void) elf_flagdata(data_tgt, ELF_C_SET, ELF_F_DIRTY); 1429 1430 /* 1431 * This symbol may already have been marked to 1432 * be ignored by another relocation referencing 1433 * the same symbol or if this object file has 1434 * already been processed by an earlier link 1435 * invocation. 1436 */ 1437 if (rsym.st_shndx != SHN_SUNW_IGNORE) { 1438 rsym.st_shndx = SHN_SUNW_IGNORE; 1439 (void) gelf_update_sym(data_sym, ndx, &rsym); 1440 } 1441 } 1442 } 1443 1444 if (mod && elf_update(elf, ELF_C_WRITE) == -1) 1445 goto err; 1446 1447 (void) elf_end(elf); 1448 (void) close(fd); 1449 1450 while ((pair = bufs) != NULL) { 1451 bufs = pair->dlp_next; 1452 dt_free(dtp, pair->dlp_str); 1453 dt_free(dtp, pair->dlp_sym); 1454 dt_free(dtp, pair); 1455 } 1456 1457 return (0); 1458 1459 err: 1460 return (dt_link_error(dtp, elf, fd, bufs, 1461 "an error was encountered while processing %s", obj)); 1462 } 1463 1464 int 1465 dtrace_program_link(dtrace_hdl_t *dtp, dtrace_prog_t *pgp, uint_t dflags, 1466 const char *file, int objc, char *const objv[]) 1467 { 1468 char drti[PATH_MAX]; 1469 dof_hdr_t *dof; 1470 int fd, status, i, cur; 1471 char *cmd, tmp; 1472 size_t len; 1473 int eprobes = 0, ret = 0; 1474 1475 /* 1476 * A NULL program indicates a special use in which we just link 1477 * together a bunch of object files specified in objv and then 1478 * unlink(2) those object files. 1479 */ 1480 if (pgp == NULL) { 1481 const char *fmt = "%s -o %s -r"; 1482 1483 len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file) + 1; 1484 1485 for (i = 0; i < objc; i++) 1486 len += strlen(objv[i]) + 1; 1487 1488 cmd = alloca(len); 1489 1490 cur = snprintf(cmd, len, fmt, dtp->dt_ld_path, file); 1491 1492 for (i = 0; i < objc; i++) 1493 cur += snprintf(cmd + cur, len - cur, " %s", objv[i]); 1494 1495 if ((status = system(cmd)) == -1) { 1496 return (dt_link_error(dtp, NULL, -1, NULL, 1497 "failed to run %s: %s", dtp->dt_ld_path, 1498 strerror(errno))); 1499 } 1500 1501 if (WIFSIGNALED(status)) { 1502 return (dt_link_error(dtp, NULL, -1, NULL, 1503 "failed to link %s: %s failed due to signal %d", 1504 file, dtp->dt_ld_path, WTERMSIG(status))); 1505 } 1506 1507 if (WEXITSTATUS(status) != 0) { 1508 return (dt_link_error(dtp, NULL, -1, NULL, 1509 "failed to link %s: %s exited with status %d\n", 1510 file, dtp->dt_ld_path, WEXITSTATUS(status))); 1511 } 1512 1513 for (i = 0; i < objc; i++) { 1514 if (strcmp(objv[i], file) != 0) 1515 (void) unlink(objv[i]); 1516 } 1517 1518 return (0); 1519 } 1520 1521 for (i = 0; i < objc; i++) { 1522 if (process_obj(dtp, objv[i], &eprobes) != 0) 1523 return (-1); /* errno is set for us */ 1524 } 1525 1526 /* 1527 * If there are is-enabled probes then we need to force use of DOF 1528 * version 2. 1529 */ 1530 if (eprobes && pgp->dp_dofversion < DOF_VERSION_2) 1531 pgp->dp_dofversion = DOF_VERSION_2; 1532 1533 if ((dof = dtrace_dof_create(dtp, pgp, dflags)) == NULL) 1534 return (-1); /* errno is set for us */ 1535 1536 /* 1537 * Create a temporary file and then unlink it if we're going to 1538 * combine it with drti.o later. We can still refer to it in child 1539 * processes as /dev/fd/<fd>. 1540 */ 1541 if ((fd = open64(file, O_RDWR | O_CREAT | O_TRUNC, 0666)) == -1) { 1542 return (dt_link_error(dtp, NULL, -1, NULL, 1543 "failed to open %s: %s", file, strerror(errno))); 1544 } 1545 1546 /* 1547 * If -xlinktype=DOF has been selected, just write out the DOF. 1548 * Otherwise proceed to the default of generating and linking ELF. 1549 */ 1550 switch (dtp->dt_linktype) { 1551 case DT_LTYP_DOF: 1552 if (dt_write(dtp, fd, dof, dof->dofh_filesz) < dof->dofh_filesz) 1553 ret = errno; 1554 1555 if (close(fd) != 0 && ret == 0) 1556 ret = errno; 1557 1558 if (ret != 0) { 1559 return (dt_link_error(dtp, NULL, -1, NULL, 1560 "failed to write %s: %s", file, strerror(ret))); 1561 } 1562 1563 return (0); 1564 1565 case DT_LTYP_ELF: 1566 break; /* fall through to the rest of dtrace_program_link() */ 1567 1568 default: 1569 return (dt_link_error(dtp, NULL, -1, NULL, 1570 "invalid link type %u\n", dtp->dt_linktype)); 1571 } 1572 1573 1574 if (!dtp->dt_lazyload) 1575 (void) unlink(file); 1576 1577 if (dtp->dt_oflags & DTRACE_O_LP64) 1578 status = dump_elf64(dtp, dof, fd); 1579 else 1580 status = dump_elf32(dtp, dof, fd); 1581 1582 if (status != 0 || lseek(fd, 0, SEEK_SET) != 0) { 1583 return (dt_link_error(dtp, NULL, -1, NULL, 1584 "failed to write %s: %s", file, strerror(errno))); 1585 } 1586 1587 if (!dtp->dt_lazyload) { 1588 const char *fmt = "%s -o %s -r -Blocal -Breduce /dev/fd/%d %s"; 1589 1590 if (dtp->dt_oflags & DTRACE_O_LP64) { 1591 (void) snprintf(drti, sizeof (drti), 1592 "%s/64/drti.o", _dtrace_libdir); 1593 } else { 1594 (void) snprintf(drti, sizeof (drti), 1595 "%s/drti.o", _dtrace_libdir); 1596 } 1597 1598 len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file, fd, 1599 drti) + 1; 1600 1601 cmd = alloca(len); 1602 1603 (void) snprintf(cmd, len, fmt, dtp->dt_ld_path, file, fd, drti); 1604 1605 if ((status = system(cmd)) == -1) { 1606 ret = dt_link_error(dtp, NULL, -1, NULL, 1607 "failed to run %s: %s", dtp->dt_ld_path, 1608 strerror(errno)); 1609 goto done; 1610 } 1611 1612 (void) close(fd); /* release temporary file */ 1613 1614 if (WIFSIGNALED(status)) { 1615 ret = dt_link_error(dtp, NULL, -1, NULL, 1616 "failed to link %s: %s failed due to signal %d", 1617 file, dtp->dt_ld_path, WTERMSIG(status)); 1618 goto done; 1619 } 1620 1621 if (WEXITSTATUS(status) != 0) { 1622 ret = dt_link_error(dtp, NULL, -1, NULL, 1623 "failed to link %s: %s exited with status %d\n", 1624 file, dtp->dt_ld_path, WEXITSTATUS(status)); 1625 goto done; 1626 } 1627 } else { 1628 (void) close(fd); 1629 } 1630 1631 done: 1632 dtrace_dof_destroy(dtp, dof); 1633 return (ret); 1634 } 1635