1/*- 2 * Copyright (c) 2003-2008 Joseph Koshy 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include <sys/types.h> 28#include <sys/cpuset.h> 29#include <sys/param.h> 30#include <sys/endian.h> 31#include <sys/pmc.h> 32#include <sys/sysctl.h> 33#include <sys/imgact_aout.h> 34#include <sys/imgact_elf.h> 35 36#include <netinet/in.h> 37 38#include <assert.h> 39#include <err.h> 40#include <fcntl.h> 41#include <pmc.h> 42#include <pmclog.h> 43#include <stdbool.h> 44#include <stdio.h> 45#include <stdlib.h> 46#include <string.h> 47#include <sysexits.h> 48#include <unistd.h> 49 50#include "libpmcstat.h" 51 52#define min(A,B) ((A) < (B) ? (A) : (B)) 53#define max(A,B) ((A) > (B) ? (A) : (B)) 54 55/* 56 * Add the list of symbols in the given section to the list associated 57 * with the object. 58 */ 59void 60pmcstat_image_add_symbols(struct pmcstat_image *image, Elf *e, 61 Elf_Scn *scn, GElf_Shdr *sh) 62{ 63 int firsttime; 64 size_t n, newsyms, nshsyms, nfuncsyms; 65 struct pmcstat_symbol *symptr; 66 char *fnname; 67 GElf_Sym sym; 68 Elf_Data *data; 69 70 if ((data = elf_getdata(scn, NULL)) == NULL) 71 return; 72 73 /* 74 * Determine the number of functions named in this 75 * section. 76 */ 77 78 nshsyms = sh->sh_size / sh->sh_entsize; 79 for (n = nfuncsyms = 0; n < nshsyms; n++) { 80 if (gelf_getsym(data, (int) n, &sym) != &sym) 81 return; 82 if (GELF_ST_TYPE(sym.st_info) == STT_FUNC) 83 nfuncsyms++; 84 } 85 86 if (nfuncsyms == 0) 87 return; 88 89 /* 90 * Allocate space for the new entries. 91 */ 92 firsttime = image->pi_symbols == NULL; 93 symptr = reallocarray(image->pi_symbols, 94 image->pi_symcount + nfuncsyms, sizeof(*symptr)); 95 if (symptr == image->pi_symbols) /* realloc() failed. */ 96 return; 97 image->pi_symbols = symptr; 98 99 /* 100 * Append new symbols to the end of the current table. 101 */ 102 symptr += image->pi_symcount; 103 104 for (n = newsyms = 0; n < nshsyms; n++) { 105 if (gelf_getsym(data, (int) n, &sym) != &sym) 106 return; 107 if (GELF_ST_TYPE(sym.st_info) != STT_FUNC) 108 continue; 109 110 if (sym.st_shndx == STN_UNDEF) 111 continue; 112 113 if (!firsttime && pmcstat_symbol_search(image, sym.st_value)) 114 continue; /* We've seen this symbol already. */ 115 116 if ((fnname = elf_strptr(e, sh->sh_link, sym.st_name)) 117 == NULL) 118 continue; 119 120#if defined(__aarch64__) || defined(__arm__) 121 /* Ignore ARM mapping symbols. */ 122 if (fnname[0] == '$' && 123 (fnname[1] == 'a' || fnname[1] == 't' || 124 fnname[1] == 'd' || fnname[1] == 'x')) 125 continue; 126 127 /* 128 * Clear LSB from starting addresses for functions 129 * which execute in Thumb mode. We should perhaps 130 * only do this for functions in a $t mapping symbol 131 * range, but parsing mapping symbols would be a lot 132 * of work and function addresses shouldn't have the 133 * LSB set otherwise. 134 */ 135 sym.st_value &= ~1; 136#endif 137 138 symptr->ps_name = pmcstat_string_intern(fnname); 139 symptr->ps_start = sym.st_value - image->pi_vaddr; 140 symptr->ps_end = symptr->ps_start + sym.st_size; 141 142 symptr++; 143 newsyms++; 144 } 145 146 image->pi_symcount += newsyms; 147 if (image->pi_symcount == 0) 148 return; 149 150 assert(newsyms <= nfuncsyms); 151 152 /* 153 * Return space to the system if there were duplicates. 154 */ 155 if (newsyms < nfuncsyms) 156 image->pi_symbols = reallocarray(image->pi_symbols, 157 image->pi_symcount, sizeof(*symptr)); 158 159 /* 160 * Keep the list of symbols sorted. 161 */ 162 qsort(image->pi_symbols, image->pi_symcount, sizeof(*symptr), 163 pmcstat_symbol_compare); 164 165 /* 166 * Deal with function symbols that have a size of 'zero' by 167 * making them extend to the next higher address. These 168 * symbols are usually defined in assembly code. 169 */ 170 for (symptr = image->pi_symbols; 171 symptr < image->pi_symbols + (image->pi_symcount - 1); 172 symptr++) 173 if (symptr->ps_start == symptr->ps_end) 174 symptr->ps_end = (symptr+1)->ps_start; 175} 176 177/* 178 * Record the fact that PC values from 'start' to 'end' come from 179 * image 'image'. 180 */ 181 182void 183pmcstat_image_link(struct pmcstat_process *pp, struct pmcstat_image *image, 184 uintfptr_t start) 185{ 186 struct pmcstat_pcmap *pcm, *pcmnew; 187 uintfptr_t offset; 188#ifdef __powerpc__ 189 unsigned long kernbase; 190 size_t kernbase_len; 191#endif 192 193 assert(image->pi_type != PMCSTAT_IMAGE_UNKNOWN && 194 image->pi_type != PMCSTAT_IMAGE_INDETERMINABLE); 195 196 if ((pcmnew = malloc(sizeof(*pcmnew))) == NULL) 197 err(EX_OSERR, "ERROR: Cannot create a map entry"); 198 199 /* 200 * PowerPC kernel is of DYN type and it has a base address 201 * where it is initially loaded, before being relocated. 202 * As the address in 'start' is where the kernel was relocated to, 203 * but the symbols always use the original base address, we need to 204 * subtract it to get the correct offset. 205 */ 206#ifdef __powerpc__ 207 if (pp->pp_pid == -1) { 208 kernbase = 0; 209 kernbase_len = sizeof(kernbase); 210 if (sysctlbyname("kern.base_address", &kernbase, &kernbase_len, 211 NULL, 0) == -1) 212 warnx( 213 "WARNING: Could not retrieve kernel base address"); 214 else 215 start -= kernbase; 216 } 217#endif 218 219 /* 220 * Adjust the map entry to only cover the text portion 221 * of the object. 222 */ 223 224 offset = start - image->pi_vaddr; 225 pcmnew->ppm_lowpc = image->pi_start + offset; 226 pcmnew->ppm_highpc = image->pi_end + offset; 227 pcmnew->ppm_image = image; 228 229 assert(pcmnew->ppm_lowpc < pcmnew->ppm_highpc); 230 231 /* Overlapped mmap()'s are assumed to never occur. */ 232 TAILQ_FOREACH(pcm, &pp->pp_map, ppm_next) 233 if (pcm->ppm_lowpc >= pcmnew->ppm_highpc) 234 break; 235 236 if (pcm == NULL) 237 TAILQ_INSERT_TAIL(&pp->pp_map, pcmnew, ppm_next); 238 else 239 TAILQ_INSERT_BEFORE(pcm, pcmnew, ppm_next); 240} 241 242/* 243 * Determine whether a given executable image is an A.OUT object, and 244 * if so, fill in its parameters from the text file. 245 * Sets image->pi_type. 246 */ 247 248void 249pmcstat_image_get_aout_params(struct pmcstat_image *image, 250 struct pmcstat_args *args) 251{ 252 int fd; 253 ssize_t nbytes; 254 struct exec ex; 255 const char *path; 256 char buffer[PATH_MAX]; 257 258 path = pmcstat_string_unintern(image->pi_execpath); 259 assert(path != NULL); 260 261 if (image->pi_iskernelmodule) 262 errx(EX_SOFTWARE, 263 "ERROR: a.out kernel modules are unsupported \"%s\"", path); 264 265 (void) snprintf(buffer, sizeof(buffer), "%s%s", 266 args->pa_fsroot, path); 267 268 if ((fd = open(buffer, O_RDONLY, 0)) < 0 || 269 (nbytes = read(fd, &ex, sizeof(ex))) < 0) { 270 if (args->pa_verbosity >= 2) 271 warn("WARNING: Cannot determine type of \"%s\"", 272 path); 273 image->pi_type = PMCSTAT_IMAGE_INDETERMINABLE; 274 if (fd != -1) 275 (void) close(fd); 276 return; 277 } 278 279 (void) close(fd); 280 281 if ((unsigned) nbytes != sizeof(ex) || 282 N_BADMAG(ex)) 283 return; 284 285 image->pi_type = PMCSTAT_IMAGE_AOUT; 286 287 /* TODO: the rest of a.out processing */ 288 289 return; 290} 291 292/* 293 * Examine an ELF file to determine the size of its text segment. 294 * Sets image->pi_type if anything conclusive can be determined about 295 * this image. 296 */ 297 298void 299pmcstat_image_get_elf_params(struct pmcstat_image *image, 300 struct pmcstat_args *args) 301{ 302 int fd; 303 size_t i, nph, nsh; 304 const char *path, *elfbase; 305 char *p, *endp; 306 bool first_exec_segment; 307 uintfptr_t minva, maxva; 308 Elf *e; 309 Elf_Scn *scn; 310 GElf_Ehdr eh; 311 GElf_Phdr ph; 312 GElf_Shdr sh; 313 enum pmcstat_image_type image_type; 314 char buffer[PATH_MAX]; 315 316 assert(image->pi_type == PMCSTAT_IMAGE_UNKNOWN); 317 318 image->pi_start = minva = ~(uintfptr_t) 0; 319 image->pi_end = maxva = (uintfptr_t) 0; 320 image->pi_type = image_type = PMCSTAT_IMAGE_INDETERMINABLE; 321 image->pi_isdynamic = 0; 322 image->pi_dynlinkerpath = NULL; 323 image->pi_vaddr = 0; 324 325 path = pmcstat_string_unintern(image->pi_execpath); 326 assert(path != NULL); 327 328 /* 329 * Look for files under FSROOT/PATHNAME. 330 */ 331 (void) snprintf(buffer, sizeof(buffer), "%s%s", 332 args->pa_fsroot, path); 333 334 e = NULL; 335 fd = open(buffer, O_RDONLY, 0); 336 if (fd < 0) { 337 warnx("WARNING: Cannot open \"%s\".", 338 buffer); 339 goto done; 340 } 341 342 if (elf_version(EV_CURRENT) == EV_NONE) { 343 warnx("WARNING: failed to init elf\n"); 344 goto done; 345 } 346 347 if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) { 348 warnx("WARNING: Cannot read \"%s\".", 349 buffer); 350 goto done; 351 } 352 353 if (elf_kind(e) != ELF_K_ELF) { 354 if (args->pa_verbosity >= 2) 355 warnx("WARNING: Cannot determine the type of \"%s\".", 356 buffer); 357 goto done; 358 } 359 360 if (gelf_getehdr(e, &eh) != &eh) { 361 warnx( 362 "WARNING: Cannot retrieve the ELF Header for \"%s\": %s.", 363 buffer, elf_errmsg(-1)); 364 goto done; 365 } 366 367 if (eh.e_type != ET_EXEC && eh.e_type != ET_DYN && 368 !(image->pi_iskernelmodule && eh.e_type == ET_REL)) { 369 warnx("WARNING: \"%s\" is of an unsupported ELF type.", 370 buffer); 371 goto done; 372 } 373 374 image_type = eh.e_ident[EI_CLASS] == ELFCLASS32 ? 375 PMCSTAT_IMAGE_ELF32 : PMCSTAT_IMAGE_ELF64; 376 377 /* 378 * Determine the virtual address where an executable would be 379 * loaded. Additionally, for dynamically linked executables, 380 * save the pathname to the runtime linker. 381 */ 382 if (eh.e_type != ET_REL) { 383 if (elf_getphnum(e, &nph) == 0) { 384 warnx( 385"WARNING: Could not determine the number of program headers in \"%s\": %s.", 386 buffer, 387 elf_errmsg(-1)); 388 goto done; 389 } 390 first_exec_segment = true; 391 for (i = 0; i < eh.e_phnum; i++) { 392 if (gelf_getphdr(e, i, &ph) != &ph) { 393 warnx( 394"WARNING: Retrieval of PHDR entry #%ju in \"%s\" failed: %s.", 395 (uintmax_t) i, buffer, elf_errmsg(-1)); 396 goto done; 397 } 398 switch (ph.p_type) { 399 case PT_DYNAMIC: 400 image->pi_isdynamic = 1; 401 break; 402 case PT_INTERP: 403 if ((elfbase = elf_rawfile(e, NULL)) == NULL) { 404 warnx( 405"WARNING: Cannot retrieve the interpreter for \"%s\": %s.", 406 buffer, elf_errmsg(-1)); 407 goto done; 408 } 409 image->pi_dynlinkerpath = 410 pmcstat_string_intern(elfbase + 411 ph.p_offset); 412 break; 413 case PT_LOAD: 414 if ((ph.p_flags & PF_X) != 0 && 415 first_exec_segment) { 416 image->pi_vaddr = ph.p_vaddr & (-ph.p_align); 417 first_exec_segment = false; 418 } 419 break; 420 } 421 } 422 } 423 424 /* 425 * Get the min and max VA associated with this ELF object. 426 */ 427 if (elf_getshnum(e, &nsh) == 0) { 428 warnx( 429"WARNING: Could not determine the number of sections for \"%s\": %s.", 430 buffer, elf_errmsg(-1)); 431 goto done; 432 } 433 434 for (i = 0; i < nsh; i++) { 435 if ((scn = elf_getscn(e, i)) == NULL || 436 gelf_getshdr(scn, &sh) != &sh) { 437 warnx( 438"WARNING: Could not retrieve section header #%ju in \"%s\": %s.", 439 (uintmax_t) i, buffer, elf_errmsg(-1)); 440 goto done; 441 } 442 if (sh.sh_flags & SHF_EXECINSTR) { 443 minva = min(minva, sh.sh_addr); 444 maxva = max(maxva, sh.sh_addr + sh.sh_size); 445 } 446 if (sh.sh_type == SHT_SYMTAB || sh.sh_type == SHT_DYNSYM) 447 pmcstat_image_add_symbols(image, e, scn, &sh); 448 } 449 450 image->pi_start = minva; 451 image->pi_end = maxva; 452 image->pi_type = image_type; 453 image->pi_fullpath = pmcstat_string_intern(buffer); 454 455 /* Build display name 456 */ 457 endp = buffer; 458 for (p = buffer; *p; p++) 459 if (*p == '/') 460 endp = p+1; 461 image->pi_name = pmcstat_string_intern(endp); 462 463 done: 464 (void) elf_end(e); 465 if (fd >= 0) 466 (void) close(fd); 467 return; 468} 469 470/* 471 * Given an image descriptor, determine whether it is an ELF, or AOUT. 472 * If no handler claims the image, set its type to 'INDETERMINABLE'. 473 */ 474 475void 476pmcstat_image_determine_type(struct pmcstat_image *image, 477 struct pmcstat_args *args) 478{ 479 assert(image->pi_type == PMCSTAT_IMAGE_UNKNOWN); 480 481 /* Try each kind of handler in turn */ 482 if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN) 483 pmcstat_image_get_elf_params(image, args); 484 if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN) 485 pmcstat_image_get_aout_params(image, args); 486 487 /* 488 * Otherwise, remember that we tried to determine 489 * the object's type and had failed. 490 */ 491 if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN) 492 image->pi_type = PMCSTAT_IMAGE_INDETERMINABLE; 493} 494 495/* 496 * Locate an image descriptor given an interned path, adding a fresh 497 * descriptor to the cache if necessary. This function also finds a 498 * suitable name for this image's sample file. 499 * 500 * We defer filling in the file format specific parts of the image 501 * structure till the time we actually see a sample that would fall 502 * into this image. 503 */ 504 505struct pmcstat_image * 506pmcstat_image_from_path(pmcstat_interned_string internedpath, 507 int iskernelmodule, struct pmcstat_args *args, 508 struct pmc_plugins *plugins) 509{ 510 int hash; 511 struct pmcstat_image *pi; 512 513 hash = pmcstat_string_lookup_hash(internedpath); 514 515 /* First, look for an existing entry. */ 516 LIST_FOREACH(pi, &pmcstat_image_hash[hash], pi_next) 517 if (pi->pi_execpath == internedpath && 518 pi->pi_iskernelmodule == iskernelmodule) 519 return (pi); 520 521 /* 522 * Allocate a new entry and place it at the head of the hash 523 * and LRU lists. 524 */ 525 pi = malloc(sizeof(*pi)); 526 if (pi == NULL) 527 return (NULL); 528 529 pi->pi_type = PMCSTAT_IMAGE_UNKNOWN; 530 pi->pi_execpath = internedpath; 531 pi->pi_start = ~0; 532 pi->pi_end = 0; 533 pi->pi_entry = 0; 534 pi->pi_vaddr = 0; 535 pi->pi_isdynamic = 0; 536 pi->pi_iskernelmodule = iskernelmodule; 537 pi->pi_dynlinkerpath = NULL; 538 pi->pi_symbols = NULL; 539 pi->pi_symcount = 0; 540 pi->pi_addr2line = NULL; 541 542 if (plugins[args->pa_pplugin].pl_initimage != NULL) 543 plugins[args->pa_pplugin].pl_initimage(pi); 544 if (plugins[args->pa_plugin].pl_initimage != NULL) 545 plugins[args->pa_plugin].pl_initimage(pi); 546 547 LIST_INSERT_HEAD(&pmcstat_image_hash[hash], pi, pi_next); 548 549 return (pi); 550} 551