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, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2003 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 #include <sys/types.h> 30 #include <sys/stat.h> 31 #include <sys/mman.h> 32 #include <sys/zmod.h> 33 #include <ctf_impl.h> 34 #include <unistd.h> 35 #include <fcntl.h> 36 #include <errno.h> 37 #ifdef illumos 38 #include <dlfcn.h> 39 #else 40 #include <zlib.h> 41 #endif 42 #include <gelf.h> 43 44 #ifdef illumos 45 #ifdef _LP64 46 static const char *_libctf_zlib = "/usr/lib/64/libz.so"; 47 #else 48 static const char *_libctf_zlib = "/usr/lib/libz.so"; 49 #endif 50 #endif 51 52 static struct { 53 int (*z_uncompress)(uchar_t *, ulong_t *, const uchar_t *, ulong_t); 54 const char *(*z_error)(int); 55 void *z_dlp; 56 } zlib; 57 58 static size_t _PAGESIZE; 59 static size_t _PAGEMASK; 60 61 #ifdef illumos 62 #pragma init(_libctf_init) 63 #else 64 void _libctf_init(void) __attribute__ ((constructor)); 65 #endif 66 void 67 _libctf_init(void) 68 { 69 #ifdef illumos 70 const char *p = getenv("LIBCTF_DECOMPRESSOR"); 71 72 if (p != NULL) 73 _libctf_zlib = p; /* use alternate decompression library */ 74 #endif 75 76 _libctf_debug = getenv("LIBCTF_DEBUG") != NULL; 77 78 _PAGESIZE = getpagesize(); 79 _PAGEMASK = ~(_PAGESIZE - 1); 80 } 81 82 /* 83 * Attempt to dlopen the decompression library and locate the symbols of 84 * interest that we will need to call. This information in cached so 85 * that multiple calls to ctf_bufopen() do not need to reopen the library. 86 */ 87 void * 88 ctf_zopen(int *errp) 89 { 90 #ifdef illumos 91 ctf_dprintf("decompressing CTF data using %s\n", _libctf_zlib); 92 93 if (zlib.z_dlp != NULL) 94 return (zlib.z_dlp); /* library is already loaded */ 95 96 if (access(_libctf_zlib, R_OK) == -1) 97 return (ctf_set_open_errno(errp, ECTF_ZMISSING)); 98 99 if ((zlib.z_dlp = dlopen(_libctf_zlib, RTLD_LAZY | RTLD_LOCAL)) == NULL) 100 return (ctf_set_open_errno(errp, ECTF_ZINIT)); 101 102 zlib.z_uncompress = (int (*)(uchar_t *, ulong_t *, const uchar_t *, ulong_t)) dlsym(zlib.z_dlp, "uncompress"); 103 zlib.z_error = (const char *(*)(int)) dlsym(zlib.z_dlp, "zError"); 104 105 if (zlib.z_uncompress == NULL || zlib.z_error == NULL) { 106 (void) dlclose(zlib.z_dlp); 107 bzero(&zlib, sizeof (zlib)); 108 return (ctf_set_open_errno(errp, ECTF_ZINIT)); 109 } 110 #else 111 zlib.z_uncompress = uncompress; 112 zlib.z_error = zError; 113 114 /* Dummy return variable as 'no error' */ 115 zlib.z_dlp = (void *) (uintptr_t) 1; 116 #endif 117 118 return (zlib.z_dlp); 119 } 120 121 /* 122 * The ctf_bufopen() routine calls these subroutines, defined by <sys/zmod.h>, 123 * which we then patch through to the functions in the decompression library. 124 */ 125 int 126 z_uncompress(void *dst, size_t *dstlen, const void *src, size_t srclen) 127 { 128 return (zlib.z_uncompress(dst, (ulong_t *)dstlen, src, srclen)); 129 } 130 131 const char * 132 z_strerror(int err) 133 { 134 return (zlib.z_error(err)); 135 } 136 137 /* 138 * Convert a 32-bit ELF file header into GElf. 139 */ 140 static void 141 ehdr_to_gelf(const Elf32_Ehdr *src, GElf_Ehdr *dst) 142 { 143 bcopy(src->e_ident, dst->e_ident, EI_NIDENT); 144 dst->e_type = src->e_type; 145 dst->e_machine = src->e_machine; 146 dst->e_version = src->e_version; 147 dst->e_entry = (Elf64_Addr)src->e_entry; 148 dst->e_phoff = (Elf64_Off)src->e_phoff; 149 dst->e_shoff = (Elf64_Off)src->e_shoff; 150 dst->e_flags = src->e_flags; 151 dst->e_ehsize = src->e_ehsize; 152 dst->e_phentsize = src->e_phentsize; 153 dst->e_phnum = src->e_phnum; 154 dst->e_shentsize = src->e_shentsize; 155 dst->e_shnum = src->e_shnum; 156 dst->e_shstrndx = src->e_shstrndx; 157 } 158 159 /* 160 * Convert a 32-bit ELF section header into GElf. 161 */ 162 static void 163 shdr_to_gelf(const Elf32_Shdr *src, GElf_Shdr *dst) 164 { 165 dst->sh_name = src->sh_name; 166 dst->sh_type = src->sh_type; 167 dst->sh_flags = src->sh_flags; 168 dst->sh_addr = src->sh_addr; 169 dst->sh_offset = src->sh_offset; 170 dst->sh_size = src->sh_size; 171 dst->sh_link = src->sh_link; 172 dst->sh_info = src->sh_info; 173 dst->sh_addralign = src->sh_addralign; 174 dst->sh_entsize = src->sh_entsize; 175 } 176 177 /* 178 * In order to mmap a section from the ELF file, we must round down sh_offset 179 * to the previous page boundary, and mmap the surrounding page. We store 180 * the pointer to the start of the actual section data back into sp->cts_data. 181 */ 182 const void * 183 ctf_sect_mmap(ctf_sect_t *sp, int fd) 184 { 185 size_t pageoff = sp->cts_offset & ~_PAGEMASK; 186 187 caddr_t base = mmap64(NULL, sp->cts_size + pageoff, PROT_READ, 188 MAP_PRIVATE, fd, sp->cts_offset & _PAGEMASK); 189 190 if (base != MAP_FAILED) 191 sp->cts_data = base + pageoff; 192 193 return (base); 194 } 195 196 /* 197 * Since sp->cts_data has the adjusted offset, we have to again round down 198 * to get the actual mmap address and round up to get the size. 199 */ 200 void 201 ctf_sect_munmap(const ctf_sect_t *sp) 202 { 203 uintptr_t addr = (uintptr_t)sp->cts_data; 204 uintptr_t pageoff = addr & ~_PAGEMASK; 205 206 (void) munmap((void *)(addr - pageoff), sp->cts_size + pageoff); 207 } 208 209 /* 210 * Open the specified file descriptor and return a pointer to a CTF container. 211 * The file can be either an ELF file or raw CTF file. The caller is 212 * responsible for closing the file descriptor when it is no longer needed. 213 */ 214 ctf_file_t * 215 ctf_fdopen(int fd, int *errp) 216 { 217 ctf_sect_t ctfsect, symsect, strsect; 218 ctf_file_t *fp = NULL; 219 size_t shstrndx, shnum; 220 221 struct stat64 st; 222 ssize_t nbytes; 223 224 union { 225 ctf_preamble_t ctf; 226 Elf32_Ehdr e32; 227 GElf_Ehdr e64; 228 } hdr; 229 230 bzero(&ctfsect, sizeof (ctf_sect_t)); 231 bzero(&symsect, sizeof (ctf_sect_t)); 232 bzero(&strsect, sizeof (ctf_sect_t)); 233 bzero(&hdr, sizeof (hdr)); 234 235 if (fstat64(fd, &st) == -1) 236 return (ctf_set_open_errno(errp, errno)); 237 238 if ((nbytes = pread64(fd, &hdr, sizeof (hdr), 0)) <= 0) 239 return (ctf_set_open_errno(errp, nbytes < 0? errno : ECTF_FMT)); 240 241 /* 242 * If we have read enough bytes to form a CTF header and the magic 243 * string matches, attempt to interpret the file as raw CTF. 244 */ 245 if (nbytes >= (ssize_t) sizeof (ctf_preamble_t) && 246 hdr.ctf.ctp_magic == CTF_MAGIC) { 247 if (hdr.ctf.ctp_version > CTF_VERSION) 248 return (ctf_set_open_errno(errp, ECTF_CTFVERS)); 249 250 ctfsect.cts_data = mmap64(NULL, st.st_size, PROT_READ, 251 MAP_PRIVATE, fd, 0); 252 253 if (ctfsect.cts_data == MAP_FAILED) 254 return (ctf_set_open_errno(errp, errno)); 255 256 ctfsect.cts_name = _CTF_SECTION; 257 ctfsect.cts_type = SHT_PROGBITS; 258 ctfsect.cts_flags = SHF_ALLOC; 259 ctfsect.cts_size = (size_t)st.st_size; 260 ctfsect.cts_entsize = 1; 261 ctfsect.cts_offset = 0; 262 263 if ((fp = ctf_bufopen(&ctfsect, NULL, NULL, errp)) == NULL) 264 ctf_sect_munmap(&ctfsect); 265 266 return (fp); 267 } 268 269 /* 270 * If we have read enough bytes to form an ELF header and the magic 271 * string matches, attempt to interpret the file as an ELF file. We 272 * do our own largefile ELF processing, and convert everything to 273 * GElf structures so that clients can operate on any data model. 274 */ 275 if (nbytes >= (ssize_t) sizeof (Elf32_Ehdr) && 276 bcmp(&hdr.e32.e_ident[EI_MAG0], ELFMAG, SELFMAG) == 0) { 277 #if BYTE_ORDER == _BIG_ENDIAN 278 uchar_t order = ELFDATA2MSB; 279 #else 280 uchar_t order = ELFDATA2LSB; 281 #endif 282 GElf_Shdr *sp; 283 284 void *strs_map; 285 size_t strs_mapsz, i; 286 char *strs; 287 288 if (hdr.e32.e_ident[EI_DATA] != order) 289 return (ctf_set_open_errno(errp, ECTF_ENDIAN)); 290 if (hdr.e32.e_version != EV_CURRENT) 291 return (ctf_set_open_errno(errp, ECTF_ELFVERS)); 292 293 if (hdr.e32.e_ident[EI_CLASS] == ELFCLASS64) { 294 if (nbytes < (ssize_t) sizeof (GElf_Ehdr)) 295 return (ctf_set_open_errno(errp, ECTF_FMT)); 296 } else { 297 Elf32_Ehdr e32 = hdr.e32; 298 ehdr_to_gelf(&e32, &hdr.e64); 299 } 300 301 shnum = hdr.e64.e_shnum; 302 shstrndx = hdr.e64.e_shstrndx; 303 304 /* Extended ELF sections */ 305 if ((shstrndx == SHN_XINDEX) || (shnum == 0)) { 306 if (hdr.e32.e_ident[EI_CLASS] == ELFCLASS32) { 307 Elf32_Shdr x32; 308 309 if (pread64(fd, &x32, sizeof (x32), 310 hdr.e64.e_shoff) != sizeof (x32)) 311 return (ctf_set_open_errno(errp, 312 errno)); 313 314 shnum = x32.sh_size; 315 shstrndx = x32.sh_link; 316 } else { 317 Elf64_Shdr x64; 318 319 if (pread64(fd, &x64, sizeof (x64), 320 hdr.e64.e_shoff) != sizeof (x64)) 321 return (ctf_set_open_errno(errp, 322 errno)); 323 324 shnum = x64.sh_size; 325 shstrndx = x64.sh_link; 326 } 327 } 328 329 if (shstrndx >= shnum) 330 return (ctf_set_open_errno(errp, ECTF_CORRUPT)); 331 332 nbytes = sizeof (GElf_Shdr) * shnum; 333 334 if ((sp = malloc(nbytes)) == NULL) 335 return (ctf_set_open_errno(errp, errno)); 336 337 /* 338 * Read in and convert to GElf the array of Shdr structures 339 * from e_shoff so we can locate sections of interest. 340 */ 341 if (hdr.e32.e_ident[EI_CLASS] == ELFCLASS32) { 342 Elf32_Shdr *sp32; 343 344 nbytes = sizeof (Elf32_Shdr) * shnum; 345 346 if ((sp32 = malloc(nbytes)) == NULL || pread64(fd, 347 sp32, nbytes, hdr.e64.e_shoff) != nbytes) { 348 free(sp); 349 free(sp32); 350 return (ctf_set_open_errno(errp, errno)); 351 } 352 353 for (i = 0; i < shnum; i++) 354 shdr_to_gelf(&sp32[i], &sp[i]); 355 356 free(sp32); 357 358 } else if (pread64(fd, sp, nbytes, hdr.e64.e_shoff) != nbytes) { 359 free(sp); 360 return (ctf_set_open_errno(errp, errno)); 361 } 362 363 /* 364 * Now mmap the section header strings section so that we can 365 * perform string comparison on the section names. 366 */ 367 strs_mapsz = sp[shstrndx].sh_size + 368 (sp[shstrndx].sh_offset & ~_PAGEMASK); 369 370 strs_map = mmap64(NULL, strs_mapsz, PROT_READ, MAP_PRIVATE, 371 fd, sp[shstrndx].sh_offset & _PAGEMASK); 372 373 strs = (char *)strs_map + 374 (sp[shstrndx].sh_offset & ~_PAGEMASK); 375 376 if (strs_map == MAP_FAILED) { 377 free(sp); 378 return (ctf_set_open_errno(errp, ECTF_MMAP)); 379 } 380 381 /* 382 * Iterate over the section header array looking for the CTF 383 * section and symbol table. The strtab is linked to symtab. 384 */ 385 for (i = 0; i < shnum; i++) { 386 const GElf_Shdr *shp = &sp[i]; 387 const GElf_Shdr *lhp = &sp[shp->sh_link]; 388 389 if (shp->sh_link >= shnum) 390 continue; /* corrupt sh_link field */ 391 392 if (shp->sh_name >= sp[shstrndx].sh_size || 393 lhp->sh_name >= sp[shstrndx].sh_size) 394 continue; /* corrupt sh_name field */ 395 396 if (shp->sh_type == SHT_PROGBITS && 397 strcmp(strs + shp->sh_name, _CTF_SECTION) == 0) { 398 ctfsect.cts_name = strs + shp->sh_name; 399 ctfsect.cts_type = shp->sh_type; 400 ctfsect.cts_flags = shp->sh_flags; 401 ctfsect.cts_size = shp->sh_size; 402 ctfsect.cts_entsize = shp->sh_entsize; 403 ctfsect.cts_offset = (off64_t)shp->sh_offset; 404 405 } else if (shp->sh_type == SHT_SYMTAB) { 406 symsect.cts_name = strs + shp->sh_name; 407 symsect.cts_type = shp->sh_type; 408 symsect.cts_flags = shp->sh_flags; 409 symsect.cts_size = shp->sh_size; 410 symsect.cts_entsize = shp->sh_entsize; 411 symsect.cts_offset = (off64_t)shp->sh_offset; 412 413 strsect.cts_name = strs + lhp->sh_name; 414 strsect.cts_type = lhp->sh_type; 415 strsect.cts_flags = lhp->sh_flags; 416 strsect.cts_size = lhp->sh_size; 417 strsect.cts_entsize = lhp->sh_entsize; 418 strsect.cts_offset = (off64_t)lhp->sh_offset; 419 } 420 } 421 422 free(sp); /* free section header array */ 423 424 if (ctfsect.cts_type == SHT_NULL) { 425 (void) munmap(strs_map, strs_mapsz); 426 return (ctf_set_open_errno(errp, ECTF_NOCTFDATA)); 427 } 428 429 /* 430 * Now mmap the CTF data, symtab, and strtab sections and 431 * call ctf_bufopen() to do the rest of the work. 432 */ 433 if (ctf_sect_mmap(&ctfsect, fd) == MAP_FAILED) { 434 (void) munmap(strs_map, strs_mapsz); 435 return (ctf_set_open_errno(errp, ECTF_MMAP)); 436 } 437 438 if (symsect.cts_type != SHT_NULL && 439 strsect.cts_type != SHT_NULL) { 440 if (ctf_sect_mmap(&symsect, fd) == MAP_FAILED || 441 ctf_sect_mmap(&strsect, fd) == MAP_FAILED) { 442 (void) ctf_set_open_errno(errp, ECTF_MMAP); 443 goto bad; /* unmap all and abort */ 444 } 445 fp = ctf_bufopen(&ctfsect, &symsect, &strsect, errp); 446 } else 447 fp = ctf_bufopen(&ctfsect, NULL, NULL, errp); 448 bad: 449 if (fp == NULL) { 450 ctf_sect_munmap(&ctfsect); 451 ctf_sect_munmap(&symsect); 452 ctf_sect_munmap(&strsect); 453 } else 454 fp->ctf_flags |= LCTF_MMAP; 455 456 (void) munmap(strs_map, strs_mapsz); 457 return (fp); 458 } 459 460 return (ctf_set_open_errno(errp, ECTF_FMT)); 461 } 462 463 /* 464 * Open the specified file and return a pointer to a CTF container. The file 465 * can be either an ELF file or raw CTF file. This is just a convenient 466 * wrapper around ctf_fdopen() for callers. 467 */ 468 ctf_file_t * 469 ctf_open(const char *filename, int *errp) 470 { 471 ctf_file_t *fp; 472 int fd; 473 474 if ((fd = open64(filename, O_RDONLY)) == -1) { 475 if (errp != NULL) 476 *errp = errno; 477 return (NULL); 478 } 479 480 fp = ctf_fdopen(fd, errp); 481 (void) close(fd); 482 return (fp); 483 } 484 485 /* 486 * Write the uncompressed CTF data stream to the specified file descriptor. 487 * This is useful for saving the results of dynamic CTF containers. 488 */ 489 int 490 ctf_write(ctf_file_t *fp, int fd) 491 { 492 const uchar_t *buf = fp->ctf_base; 493 ssize_t resid = fp->ctf_size; 494 ssize_t len; 495 496 while (resid != 0) { 497 if ((len = write(fd, buf, resid)) <= 0) 498 return (ctf_set_errno(fp, errno)); 499 resid -= len; 500 buf += len; 501 } 502 503 return (0); 504 } 505 506 /* 507 * Set the CTF library client version to the specified version. If version is 508 * zero, we just return the default library version number. 509 */ 510 int 511 ctf_version(int version) 512 { 513 if (version < 0) { 514 errno = EINVAL; 515 return (-1); 516 } 517 518 if (version > 0) { 519 if (version > CTF_VERSION) { 520 errno = ENOTSUP; 521 return (-1); 522 } 523 ctf_dprintf("ctf_version: client using version %d\n", version); 524 _libctf_version = version; 525 } 526 527 return (_libctf_version); 528 } 529