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 2006 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, uintptr_t addr, uint_t shn, GElf_Sym *sym) 719 { 720 int i, ret = -1; 721 GElf_Sym s; 722 723 for (i = 0; gelf_getsym(data_sym, i, sym) != NULL; i++) { 724 if (GELF_ST_TYPE(sym->st_info) == STT_FUNC && 725 shn == sym->st_shndx && 726 sym->st_value <= addr && 727 addr < sym->st_value + sym->st_size) { 728 if (GELF_ST_BIND(sym->st_info) == STB_GLOBAL) 729 return (0); 730 731 ret = 0; 732 s = *sym; 733 } 734 } 735 736 if (ret == 0) 737 *sym = s; 738 return (ret); 739 } 740 741 #if defined(__sparc) 742 743 #define DT_OP_RET 0x81c7e008 744 #define DT_OP_NOP 0x01000000 745 #define DT_OP_CALL 0x40000000 746 #define DT_OP_CLR_O0 0x90102000 747 748 #define DT_IS_MOV_O7(inst) (((inst) & 0xffffe000) == 0x9e100000) 749 #define DT_IS_RESTORE(inst) (((inst) & 0xc1f80000) == 0x81e80000) 750 #define DT_IS_RETL(inst) (((inst) & 0xfff83fff) == 0x81c02008) 751 752 #define DT_RS2(inst) ((inst) & 0x1f) 753 #define DT_MAKE_RETL(reg) (0x81c02008 | ((reg) << 14)) 754 755 /*ARGSUSED*/ 756 static int 757 dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela, 758 uint32_t *off) 759 { 760 uint32_t *ip; 761 762 if ((rela->r_offset & (sizeof (uint32_t) - 1)) != 0) 763 return (-1); 764 765 /*LINTED*/ 766 ip = (uint32_t *)(p + rela->r_offset); 767 768 /* 769 * We only know about some specific relocation types. 770 */ 771 if (GELF_R_TYPE(rela->r_info) != R_SPARC_WDISP30 && 772 GELF_R_TYPE(rela->r_info) != R_SPARC_WPLT30) 773 return (-1); 774 775 /* 776 * We may have already processed this object file in an earlier linker 777 * invocation. Check to see if the present instruction sequence matches 778 * the one we would install. 779 */ 780 if (isenabled) { 781 if (ip[0] == DT_OP_CLR_O0) 782 return (0); 783 } else { 784 if (DT_IS_RESTORE(ip[1])) { 785 if (ip[0] == DT_OP_RET) 786 return (0); 787 } else if (DT_IS_MOV_O7(ip[1])) { 788 if (DT_IS_RETL(ip[0])) 789 return (0); 790 } else { 791 if (ip[0] == DT_OP_NOP) { 792 (*off) += sizeof (ip[0]); 793 return (0); 794 } 795 } 796 } 797 798 /* 799 * We only expect call instructions with a displacement of 0. 800 */ 801 if (ip[0] != DT_OP_CALL) { 802 dt_dprintf("found %x instead of a call instruction at %llx\n", 803 ip[0], (u_longlong_t)rela->r_offset); 804 return (-1); 805 } 806 807 if (isenabled) { 808 /* 809 * It would necessarily indicate incorrect usage if an is- 810 * enabled probe were tail-called so flag that as an error. 811 * It's also potentially (very) tricky to handle gracefully, 812 * but could be done if this were a desired use scenario. 813 */ 814 if (DT_IS_RESTORE(ip[1]) || DT_IS_MOV_O7(ip[1])) { 815 dt_dprintf("tail call to is-enabled probe at %llx\n", 816 (u_longlong_t)rela->r_offset); 817 return (-1); 818 } 819 820 ip[0] = DT_OP_CLR_O0; 821 } else { 822 /* 823 * If the call is followed by a restore, it's a tail call so 824 * change the call to a ret. If the call if followed by a mov 825 * of a register into %o7, it's a tail call in leaf context 826 * so change the call to a retl-like instruction that returns 827 * to that register value + 8 (rather than the typical %o7 + 828 * 8). Otherwise we adjust the offset to land on what was 829 * once the delay slot of the call so we correctly get all 830 * the arguments. 831 */ 832 if (DT_IS_RESTORE(ip[1])) { 833 ip[0] = DT_OP_RET; 834 } else if (DT_IS_MOV_O7(ip[1])) { 835 ip[0] = DT_MAKE_RETL(DT_RS2(ip[1])); 836 } else { 837 ip[0] = DT_OP_NOP; 838 (*off) += sizeof (ip[0]); 839 } 840 } 841 842 return (0); 843 } 844 845 #elif defined(__i386) || defined(__amd64) 846 847 #define DT_OP_NOP 0x90 848 #define DT_OP_CALL 0xe8 849 #define DT_OP_REX_RAX 0x48 850 #define DT_OP_XOR_EAX_0 0x33 851 #define DT_OP_XOR_EAX_1 0xc0 852 853 static int 854 dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela, 855 uint32_t *off) 856 { 857 uint8_t *ip = (uint8_t *)(p + rela->r_offset - 1); 858 859 /* 860 * On x86, the first byte of the instruction is the call opcode and 861 * the next four bytes are the 32-bit address; the relocation is for 862 * the address operand. We back up the offset to the first byte of 863 * the instruction. For is-enabled probes, we later advance the offset 864 * so that it hits the first nop in the instruction sequence. 865 */ 866 (*off) -= 1; 867 868 /* 869 * We only know about some specific relocation types. Luckily 870 * these types have the same values on both 32-bit and 64-bit 871 * x86 architectures. 872 */ 873 if (GELF_R_TYPE(rela->r_info) != R_386_PC32 && 874 GELF_R_TYPE(rela->r_info) != R_386_PLT32) 875 return (-1); 876 877 /* 878 * We may have already processed this object file in an earlier linker 879 * invocation. Check to see if the present instruction sequence matches 880 * the one we would install. For is-enabled probes, we advance the 881 * offset to the first nop instruction in the sequence. 882 */ 883 if (!isenabled) { 884 if (ip[0] == DT_OP_NOP && ip[1] == DT_OP_NOP && 885 ip[2] == DT_OP_NOP && ip[3] == DT_OP_NOP && 886 ip[4] == DT_OP_NOP) 887 return (0); 888 } else if (dtp->dt_oflags & DTRACE_O_LP64) { 889 if (ip[0] == DT_OP_REX_RAX && 890 ip[1] == DT_OP_XOR_EAX_0 && ip[2] == DT_OP_XOR_EAX_1 && 891 ip[3] == DT_OP_NOP && ip[4] == DT_OP_NOP) { 892 (*off) += 3; 893 return (0); 894 } 895 } else { 896 if (ip[0] == DT_OP_XOR_EAX_0 && ip[1] == DT_OP_XOR_EAX_1 && 897 ip[2] == DT_OP_NOP && ip[3] == DT_OP_NOP && 898 ip[4] == DT_OP_NOP) { 899 (*off) += 2; 900 return (0); 901 } 902 } 903 904 /* 905 * We only expect a call instrution with a 32-bit displacement. 906 */ 907 if (ip[0] != DT_OP_CALL) { 908 dt_dprintf("found %x instead of a call instruction at %llx\n", 909 ip[0], (u_longlong_t)rela->r_offset); 910 return (-1); 911 } 912 913 /* 914 * Establish the instruction sequence -- all nops for probes, and an 915 * instruction to clear the return value register (%eax/%rax) followed 916 * by nops for is-enabled probes. For is-enabled probes, we advance 917 * the offset to the first nop. This isn't stricly necessary but makes 918 * for more readable disassembly when the probe is enabled. 919 */ 920 if (!isenabled) { 921 ip[0] = DT_OP_NOP; 922 ip[1] = DT_OP_NOP; 923 ip[2] = DT_OP_NOP; 924 ip[3] = DT_OP_NOP; 925 ip[4] = DT_OP_NOP; 926 } else if (dtp->dt_oflags & DTRACE_O_LP64) { 927 ip[0] = DT_OP_REX_RAX; 928 ip[1] = DT_OP_XOR_EAX_0; 929 ip[2] = DT_OP_XOR_EAX_1; 930 ip[3] = DT_OP_NOP; 931 ip[4] = DT_OP_NOP; 932 (*off) += 3; 933 } else { 934 ip[0] = DT_OP_XOR_EAX_0; 935 ip[1] = DT_OP_XOR_EAX_1; 936 ip[2] = DT_OP_NOP; 937 ip[3] = DT_OP_NOP; 938 ip[4] = DT_OP_NOP; 939 (*off) += 2; 940 } 941 942 return (0); 943 } 944 945 #else 946 #error unknown ISA 947 #endif 948 949 /*PRINTFLIKE5*/ 950 static int 951 dt_link_error(dtrace_hdl_t *dtp, Elf *elf, int fd, dt_link_pair_t *bufs, 952 const char *format, ...) 953 { 954 va_list ap; 955 dt_link_pair_t *pair; 956 957 va_start(ap, format); 958 dt_set_errmsg(dtp, NULL, NULL, NULL, 0, format, ap); 959 va_end(ap); 960 961 if (elf != NULL) 962 (void) elf_end(elf); 963 964 if (fd >= 0) 965 (void) close(fd); 966 967 while ((pair = bufs) != NULL) { 968 bufs = pair->dlp_next; 969 dt_free(dtp, pair->dlp_str); 970 dt_free(dtp, pair->dlp_sym); 971 dt_free(dtp, pair); 972 } 973 974 return (dt_set_errno(dtp, EDT_COMPILER)); 975 } 976 977 static int 978 process_obj(dtrace_hdl_t *dtp, const char *obj, int *eprobesp) 979 { 980 static const char dt_prefix[] = "__dtrace"; 981 static const char dt_enabled[] = "enabled"; 982 static const char dt_symprefix[] = "$dtrace"; 983 static const char dt_symfmt[] = "%s%d.%s"; 984 int fd, i, ndx, eprobe, mod = 0; 985 Elf *elf = NULL; 986 GElf_Ehdr ehdr; 987 Elf_Scn *scn_rel, *scn_sym, *scn_str, *scn_tgt; 988 Elf_Data *data_rel, *data_sym, *data_str, *data_tgt; 989 GElf_Shdr shdr_rel, shdr_sym, shdr_str, shdr_tgt; 990 GElf_Sym rsym, fsym, dsym; 991 GElf_Rela rela; 992 char *s, *p, *r; 993 char pname[DTRACE_PROVNAMELEN]; 994 dt_provider_t *pvp; 995 dt_probe_t *prp; 996 uint32_t off, eclass, emachine1, emachine2; 997 size_t symsize, nsym, isym, istr, len; 998 key_t objkey; 999 dt_link_pair_t *pair, *bufs = NULL; 1000 dt_strtab_t *strtab; 1001 1002 if ((fd = open64(obj, O_RDWR)) == -1) { 1003 return (dt_link_error(dtp, elf, fd, bufs, 1004 "failed to open %s: %s", obj, strerror(errno))); 1005 } 1006 1007 if ((elf = elf_begin(fd, ELF_C_RDWR, NULL)) == NULL) { 1008 return (dt_link_error(dtp, elf, fd, bufs, 1009 "failed to process %s: %s", obj, elf_errmsg(elf_errno()))); 1010 } 1011 1012 switch (elf_kind(elf)) { 1013 case ELF_K_ELF: 1014 break; 1015 case ELF_K_AR: 1016 return (dt_link_error(dtp, elf, fd, bufs, "archives are not " 1017 "permitted; use the contents of the archive instead: %s", 1018 obj)); 1019 default: 1020 return (dt_link_error(dtp, elf, fd, bufs, 1021 "invalid file type: %s", obj)); 1022 } 1023 1024 if (gelf_getehdr(elf, &ehdr) == NULL) { 1025 return (dt_link_error(dtp, elf, fd, bufs, "corrupt file: %s", 1026 obj)); 1027 } 1028 1029 if (dtp->dt_oflags & DTRACE_O_LP64) { 1030 eclass = ELFCLASS64; 1031 #if defined(__sparc) 1032 emachine1 = emachine2 = EM_SPARCV9; 1033 #elif defined(__i386) || defined(__amd64) 1034 emachine1 = emachine2 = EM_AMD64; 1035 #endif 1036 symsize = sizeof (Elf64_Sym); 1037 } else { 1038 eclass = ELFCLASS32; 1039 #if defined(__sparc) 1040 emachine1 = EM_SPARC; 1041 emachine2 = EM_SPARC32PLUS; 1042 #elif defined(__i386) || defined(__amd64) 1043 emachine1 = emachine2 = EM_386; 1044 #endif 1045 symsize = sizeof (Elf32_Sym); 1046 } 1047 1048 if (ehdr.e_ident[EI_CLASS] != eclass) { 1049 return (dt_link_error(dtp, elf, fd, bufs, 1050 "incorrect ELF class for object file: %s", obj)); 1051 } 1052 1053 if (ehdr.e_machine != emachine1 && ehdr.e_machine != emachine2) { 1054 return (dt_link_error(dtp, elf, fd, bufs, 1055 "incorrect ELF machine type for object file: %s", obj)); 1056 } 1057 1058 /* 1059 * We use this token as a relatively unique handle for this file on the 1060 * system in order to disambiguate potential conflicts between files of 1061 * the same name which contain identially named local symbols. 1062 */ 1063 if ((objkey = ftok(obj, 0)) == (key_t)-1) { 1064 return (dt_link_error(dtp, elf, fd, bufs, 1065 "failed to generate unique key for object file: %s", obj)); 1066 } 1067 1068 scn_rel = NULL; 1069 while ((scn_rel = elf_nextscn(elf, scn_rel)) != NULL) { 1070 if (gelf_getshdr(scn_rel, &shdr_rel) == NULL) 1071 goto err; 1072 1073 /* 1074 * Skip any non-relocation sections. 1075 */ 1076 if (shdr_rel.sh_type != SHT_RELA && shdr_rel.sh_type != SHT_REL) 1077 continue; 1078 1079 if ((data_rel = elf_getdata(scn_rel, NULL)) == NULL) 1080 goto err; 1081 1082 /* 1083 * Grab the section, section header and section data for the 1084 * symbol table that this relocation section references. 1085 */ 1086 if ((scn_sym = elf_getscn(elf, shdr_rel.sh_link)) == NULL || 1087 gelf_getshdr(scn_sym, &shdr_sym) == NULL || 1088 (data_sym = elf_getdata(scn_sym, NULL)) == NULL) 1089 goto err; 1090 1091 /* 1092 * Ditto for that symbol table's string table. 1093 */ 1094 if ((scn_str = elf_getscn(elf, shdr_sym.sh_link)) == NULL || 1095 gelf_getshdr(scn_str, &shdr_str) == NULL || 1096 (data_str = elf_getdata(scn_str, NULL)) == NULL) 1097 goto err; 1098 1099 /* 1100 * Grab the section, section header and section data for the 1101 * target section for the relocations. For the relocations 1102 * we're looking for -- this will typically be the text of the 1103 * object file. 1104 */ 1105 if ((scn_tgt = elf_getscn(elf, shdr_rel.sh_info)) == NULL || 1106 gelf_getshdr(scn_tgt, &shdr_tgt) == NULL || 1107 (data_tgt = elf_getdata(scn_tgt, NULL)) == NULL) 1108 goto err; 1109 1110 /* 1111 * We're looking for relocations to symbols matching this form: 1112 * 1113 * __dtrace[enabled]_<prov>___<probe> 1114 * 1115 * For the generated object, we need to record the location 1116 * identified by the relocation, and create a new relocation 1117 * in the generated object that will be resolved at link time 1118 * to the location of the function in which the probe is 1119 * embedded. In the target object, we change the matched symbol 1120 * so that it will be ignored at link time, and we modify the 1121 * target (text) section to replace the call instruction with 1122 * one or more nops. 1123 * 1124 * If the function containing the probe is locally scoped 1125 * (static), we create an alias used by the relocation in the 1126 * generated object. The alias, a new symbol, will be global 1127 * (so that the relocation from the generated object can be 1128 * resolved), and hidden (so that it is converted to a local 1129 * symbol at link time). Such aliases have this form: 1130 * 1131 * $dtrace<key>.<function> 1132 * 1133 * We take a first pass through all the relocations to 1134 * populate our string table and count the number of extra 1135 * symbols we'll require. 1136 */ 1137 strtab = dt_strtab_create(1); 1138 nsym = 0; 1139 1140 for (i = 0; i < shdr_rel.sh_size / shdr_rel.sh_entsize; i++) { 1141 1142 if (shdr_rel.sh_type == SHT_RELA) { 1143 if (gelf_getrela(data_rel, i, &rela) == NULL) 1144 continue; 1145 } else { 1146 GElf_Rel rel; 1147 if (gelf_getrel(data_rel, i, &rel) == NULL) 1148 continue; 1149 rela.r_offset = rel.r_offset; 1150 rela.r_info = rel.r_info; 1151 rela.r_addend = 0; 1152 } 1153 1154 if (gelf_getsym(data_sym, GELF_R_SYM(rela.r_info), 1155 &rsym) == NULL) { 1156 dt_strtab_destroy(strtab); 1157 goto err; 1158 } 1159 1160 s = (char *)data_str->d_buf + rsym.st_name; 1161 1162 if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0) 1163 continue; 1164 1165 if (dt_symtab_lookup(data_sym, rela.r_offset, 1166 shdr_rel.sh_info, &fsym) != 0) { 1167 dt_strtab_destroy(strtab); 1168 goto err; 1169 } 1170 1171 if (GELF_ST_BIND(fsym.st_info) != STB_LOCAL) 1172 continue; 1173 1174 if (fsym.st_name > data_str->d_size) { 1175 dt_strtab_destroy(strtab); 1176 goto err; 1177 } 1178 1179 s = (char *)data_str->d_buf + fsym.st_name; 1180 1181 /* 1182 * If this symbol isn't of type function, we've really 1183 * driven off the rails or the object file is corrupt. 1184 */ 1185 if (GELF_ST_TYPE(fsym.st_info) != STT_FUNC) { 1186 dt_strtab_destroy(strtab); 1187 return (dt_link_error(dtp, elf, fd, bufs, 1188 "expected %s to be of type function", s)); 1189 } 1190 1191 len = snprintf(NULL, 0, dt_symfmt, dt_symprefix, 1192 objkey, s) + 1; 1193 if ((p = dt_alloc(dtp, len)) == NULL) { 1194 dt_strtab_destroy(strtab); 1195 goto err; 1196 } 1197 (void) snprintf(p, len, dt_symfmt, dt_symprefix, 1198 objkey, s); 1199 1200 if (dt_strtab_index(strtab, p) == -1) { 1201 nsym++; 1202 (void) dt_strtab_insert(strtab, p); 1203 } 1204 1205 dt_free(dtp, p); 1206 } 1207 1208 /* 1209 * If needed, allocate the additional space for the symbol 1210 * table and string table copying the old data into the new 1211 * buffers, and marking the buffers as dirty. We inject those 1212 * newly allocated buffers into the libelf data structures, but 1213 * are still responsible for freeing them once we're done with 1214 * the elf handle. 1215 */ 1216 if (nsym > 0) { 1217 /* 1218 * The first byte of the string table is reserved for 1219 * the \0 entry. 1220 */ 1221 len = dt_strtab_size(strtab) - 1; 1222 1223 assert(len > 0); 1224 assert(dt_strtab_index(strtab, "") == 0); 1225 1226 dt_strtab_destroy(strtab); 1227 1228 if ((pair = dt_alloc(dtp, sizeof (*pair))) == NULL) 1229 goto err; 1230 1231 if ((pair->dlp_str = dt_alloc(dtp, data_str->d_size + 1232 len)) == NULL) { 1233 dt_free(dtp, pair); 1234 goto err; 1235 } 1236 1237 if ((pair->dlp_sym = dt_alloc(dtp, data_sym->d_size + 1238 nsym * symsize)) == NULL) { 1239 dt_free(dtp, pair->dlp_str); 1240 dt_free(dtp, pair); 1241 goto err; 1242 } 1243 1244 pair->dlp_next = bufs; 1245 bufs = pair; 1246 1247 istr = data_str->d_size; 1248 isym = data_sym->d_size / symsize; 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 istr = 0; 1269 isym = 0; 1270 dt_strtab_destroy(strtab); 1271 } 1272 1273 /* 1274 * Now that the tables have been allocated, perform the 1275 * modifications described above. 1276 */ 1277 for (i = 0; i < shdr_rel.sh_size / shdr_rel.sh_entsize; i++) { 1278 1279 if (shdr_rel.sh_type == SHT_RELA) { 1280 if (gelf_getrela(data_rel, i, &rela) == NULL) 1281 continue; 1282 } else { 1283 GElf_Rel rel; 1284 if (gelf_getrel(data_rel, i, &rel) == NULL) 1285 continue; 1286 rela.r_offset = rel.r_offset; 1287 rela.r_info = rel.r_info; 1288 rela.r_addend = 0; 1289 } 1290 1291 ndx = GELF_R_SYM(rela.r_info); 1292 1293 if (gelf_getsym(data_sym, ndx, &rsym) == NULL || 1294 rsym.st_name > data_str->d_size) 1295 goto err; 1296 1297 s = (char *)data_str->d_buf + rsym.st_name; 1298 1299 if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0) 1300 continue; 1301 1302 s += sizeof (dt_prefix) - 1; 1303 1304 /* 1305 * Check to see if this is an 'is-enabled' check as 1306 * opposed to a normal probe. 1307 */ 1308 if (strncmp(s, dt_enabled, 1309 sizeof (dt_enabled) - 1) == 0) { 1310 s += sizeof (dt_enabled) - 1; 1311 eprobe = 1; 1312 *eprobesp = 1; 1313 dt_dprintf("is-enabled probe\n"); 1314 } else { 1315 eprobe = 0; 1316 dt_dprintf("normal probe\n"); 1317 } 1318 1319 if (*s++ != '_') 1320 goto err; 1321 1322 if ((p = strstr(s, "___")) == NULL || 1323 p - s >= sizeof (pname)) 1324 goto err; 1325 1326 bcopy(s, pname, p - s); 1327 pname[p - s] = '\0'; 1328 1329 p = strhyphenate(p + 3); /* strlen("___") */ 1330 1331 if (dt_symtab_lookup(data_sym, rela.r_offset, 1332 shdr_rel.sh_info, &fsym) != 0) 1333 goto err; 1334 1335 if (fsym.st_name > data_str->d_size) 1336 goto err; 1337 1338 assert(GELF_ST_TYPE(fsym.st_info) == STT_FUNC); 1339 1340 /* 1341 * If a NULL relocation name is passed to 1342 * dt_probe_define(), the function name is used for the 1343 * relocation. The relocation needs to use a mangled 1344 * name if the symbol is locally scoped; the function 1345 * name may need to change if we've found the global 1346 * alias for the locally scoped symbol (we prefer 1347 * global symbols to locals in dt_symtab_lookup()). 1348 */ 1349 s = (char *)data_str->d_buf + fsym.st_name; 1350 r = NULL; 1351 1352 if (GELF_ST_BIND(fsym.st_info) == STB_LOCAL) { 1353 dsym = fsym; 1354 dsym.st_name = istr; 1355 dsym.st_info = GELF_ST_INFO(STB_GLOBAL, 1356 STT_FUNC); 1357 dsym.st_other = ELF64_ST_VISIBILITY(STV_HIDDEN); 1358 (void) gelf_update_sym(data_sym, isym, &dsym); 1359 1360 r = (char *)data_str->d_buf + istr; 1361 istr += 1 + sprintf(r, dt_symfmt, 1362 dt_symprefix, objkey, s); 1363 isym++; 1364 assert(isym <= nsym); 1365 1366 } else if (strncmp(s, dt_symprefix, 1367 strlen(dt_symprefix)) == 0) { 1368 r = s; 1369 if ((s = strchr(s, '.')) == NULL) 1370 goto err; 1371 s++; 1372 } 1373 1374 if ((pvp = dt_provider_lookup(dtp, pname)) == NULL) { 1375 return (dt_link_error(dtp, elf, fd, bufs, 1376 "no such provider %s", pname)); 1377 } 1378 1379 if ((prp = dt_probe_lookup(pvp, p)) == NULL) { 1380 return (dt_link_error(dtp, elf, fd, bufs, 1381 "no such probe %s", p)); 1382 } 1383 1384 assert(fsym.st_value <= rela.r_offset); 1385 1386 off = rela.r_offset - fsym.st_value; 1387 if (dt_modtext(dtp, data_tgt->d_buf, eprobe, 1388 &rela, &off) != 0) { 1389 goto err; 1390 } 1391 1392 if (dt_probe_define(pvp, prp, s, r, off, eprobe) != 0) { 1393 return (dt_link_error(dtp, elf, fd, bufs, 1394 "failed to allocate space for probe")); 1395 } 1396 1397 mod = 1; 1398 (void) elf_flagdata(data_tgt, ELF_C_SET, ELF_F_DIRTY); 1399 1400 /* 1401 * This symbol may already have been marked to 1402 * be ignored by another relocation referencing 1403 * the same symbol or if this object file has 1404 * already been processed by an earlier link 1405 * invocation. 1406 */ 1407 if (rsym.st_shndx != SHN_SUNW_IGNORE) { 1408 rsym.st_shndx = SHN_SUNW_IGNORE; 1409 (void) gelf_update_sym(data_sym, ndx, &rsym); 1410 } 1411 } 1412 } 1413 1414 if (mod && elf_update(elf, ELF_C_WRITE) == -1) 1415 goto err; 1416 1417 (void) elf_end(elf); 1418 (void) close(fd); 1419 1420 while ((pair = bufs) != NULL) { 1421 bufs = pair->dlp_next; 1422 dt_free(dtp, pair->dlp_str); 1423 dt_free(dtp, pair->dlp_sym); 1424 dt_free(dtp, pair); 1425 } 1426 1427 return (0); 1428 1429 err: 1430 return (dt_link_error(dtp, elf, fd, bufs, 1431 "an error was encountered while processing %s", obj)); 1432 } 1433 1434 int 1435 dtrace_program_link(dtrace_hdl_t *dtp, dtrace_prog_t *pgp, uint_t dflags, 1436 const char *file, int objc, char *const objv[]) 1437 { 1438 char drti[PATH_MAX]; 1439 dof_hdr_t *dof; 1440 int fd, status, i, cur; 1441 char *cmd, tmp; 1442 size_t len; 1443 int eprobes = 0, ret = 0; 1444 1445 /* 1446 * A NULL program indicates a special use in which we just link 1447 * together a bunch of object files specified in objv and then 1448 * unlink(2) those object files. 1449 */ 1450 if (pgp == NULL) { 1451 const char *fmt = "%s -o %s -r"; 1452 1453 len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file) + 1; 1454 1455 for (i = 0; i < objc; i++) 1456 len += strlen(objv[i]) + 1; 1457 1458 cmd = alloca(len); 1459 1460 cur = snprintf(cmd, len, fmt, dtp->dt_ld_path, file); 1461 1462 for (i = 0; i < objc; i++) 1463 cur += snprintf(cmd + cur, len - cur, " %s", objv[i]); 1464 1465 if ((status = system(cmd)) == -1) { 1466 return (dt_link_error(dtp, NULL, -1, NULL, 1467 "failed to run %s: %s", dtp->dt_ld_path, 1468 strerror(errno))); 1469 } 1470 1471 if (WIFSIGNALED(status)) { 1472 return (dt_link_error(dtp, NULL, -1, NULL, 1473 "failed to link %s: %s failed due to signal %d", 1474 file, dtp->dt_ld_path, WTERMSIG(status))); 1475 } 1476 1477 if (WEXITSTATUS(status) != 0) { 1478 return (dt_link_error(dtp, NULL, -1, NULL, 1479 "failed to link %s: %s exited with status %d\n", 1480 file, dtp->dt_ld_path, WEXITSTATUS(status))); 1481 } 1482 1483 for (i = 0; i < objc; i++) { 1484 if (strcmp(objv[i], file) != 0) 1485 (void) unlink(objv[i]); 1486 } 1487 1488 return (0); 1489 } 1490 1491 for (i = 0; i < objc; i++) { 1492 if (process_obj(dtp, objv[i], &eprobes) != 0) 1493 return (-1); /* errno is set for us */ 1494 } 1495 1496 /* 1497 * If there are is-enabled probes then we need to force use of DOF 1498 * version 2. 1499 */ 1500 if (eprobes && pgp->dp_dofversion < DOF_VERSION_2) 1501 pgp->dp_dofversion = DOF_VERSION_2; 1502 1503 if ((dof = dtrace_dof_create(dtp, pgp, dflags)) == NULL) 1504 return (-1); /* errno is set for us */ 1505 1506 /* 1507 * Create a temporary file and then unlink it if we're going to 1508 * combine it with drti.o later. We can still refer to it in child 1509 * processes as /dev/fd/<fd>. 1510 */ 1511 if ((fd = open64(file, O_RDWR | O_CREAT | O_TRUNC, 0666)) == -1) { 1512 return (dt_link_error(dtp, NULL, -1, NULL, 1513 "failed to open %s: %s", file, strerror(errno))); 1514 } 1515 1516 /* 1517 * If -xlinktype=DOF has been selected, just write out the DOF. 1518 * Otherwise proceed to the default of generating and linking ELF. 1519 */ 1520 switch (dtp->dt_linktype) { 1521 case DT_LTYP_DOF: 1522 if (dt_write(dtp, fd, dof, dof->dofh_filesz) < dof->dofh_filesz) 1523 ret = errno; 1524 1525 if (close(fd) != 0 && ret == 0) 1526 ret = errno; 1527 1528 if (ret != 0) { 1529 return (dt_link_error(dtp, NULL, -1, NULL, 1530 "failed to write %s: %s", file, strerror(ret))); 1531 } 1532 1533 return (0); 1534 1535 case DT_LTYP_ELF: 1536 break; /* fall through to the rest of dtrace_program_link() */ 1537 1538 default: 1539 return (dt_link_error(dtp, NULL, -1, NULL, 1540 "invalid link type %u\n", dtp->dt_linktype)); 1541 } 1542 1543 1544 if (!dtp->dt_lazyload) 1545 (void) unlink(file); 1546 1547 if (dtp->dt_oflags & DTRACE_O_LP64) 1548 status = dump_elf64(dtp, dof, fd); 1549 else 1550 status = dump_elf32(dtp, dof, fd); 1551 1552 if (status != 0 || lseek(fd, 0, SEEK_SET) != 0) { 1553 return (dt_link_error(dtp, NULL, -1, NULL, 1554 "failed to write %s: %s", file, strerror(errno))); 1555 } 1556 1557 if (!dtp->dt_lazyload) { 1558 const char *fmt = "%s -o %s -r -Blocal -Breduce /dev/fd/%d %s"; 1559 1560 if (dtp->dt_oflags & DTRACE_O_LP64) { 1561 (void) snprintf(drti, sizeof (drti), 1562 "%s/64/drti.o", _dtrace_libdir); 1563 } else { 1564 (void) snprintf(drti, sizeof (drti), 1565 "%s/drti.o", _dtrace_libdir); 1566 } 1567 1568 len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file, fd, 1569 drti) + 1; 1570 1571 cmd = alloca(len); 1572 1573 (void) snprintf(cmd, len, fmt, dtp->dt_ld_path, file, fd, drti); 1574 1575 if ((status = system(cmd)) == -1) { 1576 ret = dt_link_error(dtp, NULL, -1, NULL, 1577 "failed to run %s: %s", dtp->dt_ld_path, 1578 strerror(errno)); 1579 goto done; 1580 } 1581 1582 (void) close(fd); /* release temporary file */ 1583 1584 if (WIFSIGNALED(status)) { 1585 ret = dt_link_error(dtp, NULL, -1, NULL, 1586 "failed to link %s: %s failed due to signal %d", 1587 file, dtp->dt_ld_path, WTERMSIG(status)); 1588 goto done; 1589 } 1590 1591 if (WEXITSTATUS(status) != 0) { 1592 ret = dt_link_error(dtp, NULL, -1, NULL, 1593 "failed to link %s: %s exited with status %d\n", 1594 file, dtp->dt_ld_path, WEXITSTATUS(status)); 1595 goto done; 1596 } 1597 } else { 1598 (void) close(fd); 1599 } 1600 1601 done: 1602 dtrace_dof_destroy(dtp, dof); 1603 return (ret); 1604 } 1605