1 // SPDX-License-Identifier: GPL-2.0 2 #include <elf.h> 3 #include <errno.h> 4 #include <fcntl.h> 5 #include <stdlib.h> 6 #include <stdio.h> 7 #include <string.h> 8 #include <linux/kernel.h> 9 #include <linux/zalloc.h> 10 #include "dso.h" 11 #include "session.h" 12 #include "thread.h" 13 #include "thread-stack.h" 14 #include "debug.h" 15 #include "namespaces.h" 16 #include "comm.h" 17 #include "map.h" 18 #include "symbol.h" 19 #include "unwind.h" 20 #include "callchain.h" 21 #include "dwarf-regs.h" 22 23 #include <api/fs/fs.h> 24 25 int thread__init_maps(struct thread *thread, struct machine *machine) 26 { 27 pid_t pid = thread__pid(thread); 28 29 if (pid == thread__tid(thread) || pid == -1) { 30 thread__set_maps(thread, maps__new(machine)); 31 } else { 32 struct thread *leader = machine__findnew_thread(machine, pid, pid); 33 34 if (leader) { 35 thread__set_maps(thread, maps__get(thread__maps(leader))); 36 thread__put(leader); 37 } 38 } 39 40 return thread__maps(thread) ? 0 : -1; 41 } 42 43 struct thread *thread__new(pid_t pid, pid_t tid) 44 NO_THREAD_SAFETY_ANALYSIS /* Allocation/creation is inherently single threaded. */ 45 { 46 RC_STRUCT(thread) *_thread = zalloc(sizeof(*_thread)); 47 struct thread *thread; 48 49 if (ADD_RC_CHK(thread, _thread) != NULL) { 50 struct comm *comm; 51 char comm_str[32]; 52 53 thread__set_pid(thread, pid); 54 thread__set_tid(thread, tid); 55 thread__set_ppid(thread, -1); 56 thread__set_cpu(thread, -1); 57 thread__set_guest_cpu(thread, -1); 58 thread__set_e_machine(thread, EM_NONE); 59 thread__set_e_is_big_endian(thread, false); 60 thread__set_lbr_stitch_enable(thread, false); 61 INIT_LIST_HEAD(thread__namespaces_list(thread)); 62 INIT_LIST_HEAD(thread__comm_list(thread)); 63 init_rwsem(thread__namespaces_lock(thread)); 64 init_rwsem(thread__comm_lock(thread)); 65 66 snprintf(comm_str, sizeof(comm_str), ":%d", tid); 67 comm = comm__new(comm_str, 0, false); 68 if (!comm) 69 goto err_thread; 70 71 list_add(&comm->list, thread__comm_list(thread)); 72 refcount_set(thread__refcnt(thread), 1); 73 /* Thread holds first ref to nsdata. */ 74 RC_CHK_ACCESS(thread)->nsinfo = nsinfo__new(pid); 75 srccode_state_init(thread__srccode_state(thread)); 76 } 77 78 return thread; 79 80 err_thread: 81 thread__delete(thread); 82 return NULL; 83 } 84 85 static void (*thread__priv_destructor)(void *priv); 86 87 void thread__set_priv_destructor(void (*destructor)(void *priv)) 88 { 89 assert(thread__priv_destructor == NULL); 90 91 thread__priv_destructor = destructor; 92 } 93 94 void thread__delete(struct thread *thread) 95 { 96 struct namespaces *namespaces, *tmp_namespaces; 97 struct comm *comm, *tmp_comm; 98 99 thread_stack__free(thread); 100 101 if (thread__maps(thread)) { 102 maps__put(thread__maps(thread)); 103 thread__set_maps(thread, NULL); 104 } 105 down_write(thread__namespaces_lock(thread)); 106 list_for_each_entry_safe(namespaces, tmp_namespaces, 107 thread__namespaces_list(thread), list) { 108 list_del_init(&namespaces->list); 109 namespaces__free(namespaces); 110 } 111 up_write(thread__namespaces_lock(thread)); 112 113 down_write(thread__comm_lock(thread)); 114 list_for_each_entry_safe(comm, tmp_comm, thread__comm_list(thread), list) { 115 list_del_init(&comm->list); 116 comm__free(comm); 117 } 118 up_write(thread__comm_lock(thread)); 119 120 nsinfo__zput(RC_CHK_ACCESS(thread)->nsinfo); 121 srccode_state_free(thread__srccode_state(thread)); 122 123 exit_rwsem(thread__namespaces_lock(thread)); 124 exit_rwsem(thread__comm_lock(thread)); 125 thread__free_stitch_list(thread); 126 127 if (thread__priv_destructor) 128 thread__priv_destructor(thread__priv(thread)); 129 130 RC_CHK_FREE(thread); 131 } 132 133 struct thread *thread__get(struct thread *thread) 134 { 135 struct thread *result; 136 137 if (RC_CHK_GET(result, thread)) 138 refcount_inc(thread__refcnt(thread)); 139 140 return result; 141 } 142 143 void thread__put(struct thread *thread) 144 { 145 if (thread && refcount_dec_and_test(thread__refcnt(thread))) 146 thread__delete(thread); 147 else 148 RC_CHK_PUT(thread); 149 } 150 151 static struct namespaces *__thread__namespaces(struct thread *thread) 152 { 153 if (list_empty(thread__namespaces_list(thread))) 154 return NULL; 155 156 return list_first_entry(thread__namespaces_list(thread), struct namespaces, list); 157 } 158 159 struct namespaces *thread__namespaces(struct thread *thread) 160 { 161 struct namespaces *ns; 162 163 down_read(thread__namespaces_lock(thread)); 164 ns = __thread__namespaces(thread); 165 up_read(thread__namespaces_lock(thread)); 166 167 return ns; 168 } 169 170 static int __thread__set_namespaces(struct thread *thread, u64 timestamp, 171 struct perf_record_namespaces *event) 172 { 173 struct namespaces *new, *curr = __thread__namespaces(thread); 174 175 new = namespaces__new(event); 176 if (!new) 177 return -ENOMEM; 178 179 list_add(&new->list, thread__namespaces_list(thread)); 180 181 if (timestamp && curr) { 182 /* 183 * setns syscall must have changed few or all the namespaces 184 * of this thread. Update end time for the namespaces 185 * previously used. 186 */ 187 curr = list_next_entry(new, list); 188 curr->end_time = timestamp; 189 } 190 191 return 0; 192 } 193 194 int thread__set_namespaces(struct thread *thread, u64 timestamp, 195 struct perf_record_namespaces *event) 196 { 197 int ret; 198 199 down_write(thread__namespaces_lock(thread)); 200 ret = __thread__set_namespaces(thread, timestamp, event); 201 up_write(thread__namespaces_lock(thread)); 202 return ret; 203 } 204 205 static struct comm *__thread__comm(struct thread *thread) 206 SHARED_LOCKS_REQUIRED(thread__comm_lock(thread)) 207 { 208 if (list_empty(thread__comm_list(thread))) 209 return NULL; 210 211 return list_first_entry(thread__comm_list(thread), struct comm, list); 212 } 213 214 struct comm *thread__comm(struct thread *thread) 215 { 216 struct comm *res = NULL; 217 218 down_read(thread__comm_lock(thread)); 219 res = __thread__comm(thread); 220 up_read(thread__comm_lock(thread)); 221 return res; 222 } 223 224 struct comm *thread__exec_comm(struct thread *thread) 225 { 226 struct comm *comm, *last = NULL, *second_last = NULL; 227 228 down_read(thread__comm_lock(thread)); 229 list_for_each_entry(comm, thread__comm_list(thread), list) { 230 if (comm->exec) { 231 up_read(thread__comm_lock(thread)); 232 return comm; 233 } 234 second_last = last; 235 last = comm; 236 } 237 up_read(thread__comm_lock(thread)); 238 239 /* 240 * 'last' with no start time might be the parent's comm of a synthesized 241 * thread (created by processing a synthesized fork event). For a main 242 * thread, that is very probably wrong. Prefer a later comm to avoid 243 * that case. 244 */ 245 if (second_last && !last->start && thread__pid(thread) == thread__tid(thread)) 246 return second_last; 247 248 return last; 249 } 250 251 static int ____thread__set_comm(struct thread *thread, const char *str, 252 u64 timestamp, bool exec) 253 EXCLUSIVE_LOCKS_REQUIRED(thread__comm_lock(thread)) 254 { 255 struct comm *new, *curr = __thread__comm(thread); 256 257 /* Override the default :tid entry */ 258 if (!thread__comm_set(thread)) { 259 int err = comm__override(curr, str, timestamp, exec); 260 if (err) 261 return err; 262 } else { 263 new = comm__new(str, timestamp, exec); 264 if (!new) 265 return -ENOMEM; 266 list_add(&new->list, thread__comm_list(thread)); 267 268 if (exec) 269 unwind__flush_access(thread__maps(thread)); 270 } 271 272 thread__set_comm_set(thread, true); 273 274 return 0; 275 } 276 277 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp, 278 bool exec) 279 { 280 int ret; 281 282 down_write(thread__comm_lock(thread)); 283 ret = ____thread__set_comm(thread, str, timestamp, exec); 284 up_write(thread__comm_lock(thread)); 285 return ret; 286 } 287 288 int thread__set_comm_from_proc(struct thread *thread) 289 { 290 char path[64]; 291 char *comm = NULL; 292 size_t sz; 293 int err = -1; 294 295 if (!(snprintf(path, sizeof(path), "%d/task/%d/comm", 296 thread__pid(thread), thread__tid(thread)) >= (int)sizeof(path)) && 297 procfs__read_str(path, &comm, &sz) == 0) { 298 /* sz==0: read got nothing, e.g. race during exit teardown */ 299 if (sz == 0) { 300 free(comm); 301 return -1; 302 } 303 comm[sz - 1] = '\0'; 304 err = thread__set_comm(thread, comm, 0); 305 } 306 307 return err; 308 } 309 310 static const char *__thread__comm_str(struct thread *thread) 311 SHARED_LOCKS_REQUIRED(thread__comm_lock(thread)) 312 { 313 const struct comm *comm = __thread__comm(thread); 314 315 if (!comm) 316 return NULL; 317 318 return comm__str(comm); 319 } 320 321 const char *thread__comm_str(struct thread *thread) 322 { 323 const char *str; 324 325 down_read(thread__comm_lock(thread)); 326 str = __thread__comm_str(thread); 327 up_read(thread__comm_lock(thread)); 328 329 return str; 330 } 331 332 static int __thread__comm_len(struct thread *thread, const char *comm) 333 { 334 if (!comm) 335 return 0; 336 thread__set_comm_len(thread, strlen(comm)); 337 338 return thread__var_comm_len(thread); 339 } 340 341 /* CHECKME: it should probably better return the max comm len from its comm list */ 342 int thread__comm_len(struct thread *thread) 343 { 344 int comm_len = thread__var_comm_len(thread); 345 346 if (!comm_len) { 347 const char *comm; 348 349 down_read(thread__comm_lock(thread)); 350 comm = __thread__comm_str(thread); 351 comm_len = __thread__comm_len(thread, comm); 352 up_read(thread__comm_lock(thread)); 353 } 354 355 return comm_len; 356 } 357 358 size_t thread__fprintf(struct thread *thread, FILE *fp) 359 { 360 return fprintf(fp, "Thread %d %s\n", thread__tid(thread), thread__comm_str(thread)) + 361 maps__fprintf(thread__maps(thread), fp); 362 } 363 364 int thread__insert_map(struct thread *thread, struct map *map) 365 { 366 int ret; 367 uint16_t e_machine; 368 369 ret = maps__fixup_overlap_and_insert(thread__maps(thread), map); 370 if (ret) 371 return ret; 372 373 e_machine = thread__e_machine(thread, /*machine=*/NULL, /*e_flags=*/NULL); 374 return unwind__prepare_access(thread__maps(thread), e_machine); 375 } 376 377 static int thread__prepare_access(struct thread *thread) 378 { 379 uint16_t e_machine = thread__e_machine(thread, /*machine=*/NULL, /*e_flags=*/NULL); 380 381 return unwind__prepare_access(thread__maps(thread), e_machine); 382 } 383 384 static int thread__clone_maps(struct thread *thread, struct thread *parent, bool do_maps_clone) 385 { 386 /* This is new thread, we share map groups for process. */ 387 if (thread__pid(thread) == thread__pid(parent)) 388 return thread__prepare_access(thread); 389 390 if (maps__equal(thread__maps(thread), thread__maps(parent))) { 391 pr_debug("broken map groups on thread %d/%d parent %d/%d\n", 392 thread__pid(thread), thread__tid(thread), 393 thread__pid(parent), thread__tid(parent)); 394 return 0; 395 } 396 /* But this one is new process, copy maps. */ 397 return do_maps_clone ? maps__copy_from(thread__maps(thread), thread__maps(parent)) : 0; 398 } 399 400 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone) 401 { 402 if (thread__comm_set(parent)) { 403 const char *comm = thread__comm_str(parent); 404 int err; 405 if (!comm) 406 return -ENOMEM; 407 err = thread__set_comm(thread, comm, timestamp); 408 if (err) 409 return err; 410 } 411 412 thread__set_ppid(thread, thread__tid(parent)); 413 return thread__clone_maps(thread, parent, do_maps_clone); 414 } 415 416 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr, 417 bool symbols, struct addr_location *al) 418 { 419 size_t i; 420 const u8 cpumodes[] = { 421 PERF_RECORD_MISC_USER, 422 PERF_RECORD_MISC_KERNEL, 423 PERF_RECORD_MISC_GUEST_USER, 424 PERF_RECORD_MISC_GUEST_KERNEL 425 }; 426 427 for (i = 0; i < ARRAY_SIZE(cpumodes); i++) { 428 if (symbols) 429 thread__find_symbol(thread, cpumodes[i], addr, al); 430 else 431 thread__find_map(thread, cpumodes[i], addr, al); 432 433 if (al->map) 434 break; 435 } 436 } 437 438 static uint16_t read_proc_e_machine_for_pid(pid_t pid, uint32_t *e_flags, bool *is_big_endian) 439 { 440 char path[6 /* "/proc/" */ + 11 /* max length of pid */ + 5 /* "/exe\0" */]; 441 int fd; 442 uint16_t e_machine = EM_NONE; 443 444 snprintf(path, sizeof(path), "/proc/%d/exe", pid); 445 fd = open(path, O_RDONLY); 446 if (fd >= 0) { 447 e_machine = dso__read_e_machine_endian(/*optional_dso=*/NULL, fd, e_flags, 448 is_big_endian); 449 close(fd); 450 } 451 return e_machine; 452 } 453 454 struct thread__e_machine_callback_args { 455 struct machine *machine; 456 uint32_t e_flags; 457 uint16_t e_machine; 458 bool is_big_endian; 459 }; 460 461 static int thread__e_machine_callback(struct map *map, void *_args) 462 { 463 struct thread__e_machine_callback_args *args = _args; 464 struct dso *dso = map__dso(map); 465 466 if (!dso) 467 return 0; // No dso, continue search. 468 469 args->e_machine = 470 dso__e_machine_endian(dso, args->machine, &args->e_flags, &args->is_big_endian); 471 return args->e_machine != EM_NONE ? 1 /* stop search */ : 0 /* continue search */; 472 } 473 474 uint16_t thread__e_machine_endian(struct thread *thread, struct machine *machine, uint32_t *e_flags, 475 bool *is_big_endian) 476 { 477 pid_t tid, pid; 478 uint16_t e_machine; 479 uint32_t local_e_flags = 0; 480 struct thread__e_machine_callback_args args; 481 482 if (!thread) { 483 if (is_big_endian) { 484 *is_big_endian = perf_arch_is_big_endian( 485 machine && machine->env ? perf_env__arch(machine->env) : NULL); 486 } 487 return perf_env__e_machine(machine ? machine->env : NULL, e_flags); 488 } 489 490 e_machine = RC_CHK_ACCESS(thread)->e_machine; 491 args.machine = machine; 492 args.e_flags = 0; 493 args.e_machine = EM_NONE; 494 args.is_big_endian = false; 495 496 if (e_machine != EM_NONE) { 497 if (e_flags) 498 *e_flags = thread__e_flags(thread); 499 if (is_big_endian) 500 *is_big_endian = thread__e_is_big_endian(thread); 501 return e_machine; 502 } 503 504 if (machine == NULL) { 505 struct maps *maps = thread__maps(thread); 506 507 machine = maps__machine(maps); 508 args.machine = machine; 509 } 510 tid = thread__tid(thread); 511 pid = thread__pid(thread); 512 if (pid != tid) { 513 struct thread *parent = machine__findnew_thread(machine, pid, pid); 514 515 if (parent) { 516 e_machine = thread__e_machine_endian(parent, machine, &local_e_flags, 517 &args.is_big_endian); 518 thread__put(parent); 519 goto out; 520 } 521 /* Something went wrong, fallback. */ 522 } 523 /* Reading on the PID thread. First try to find from the maps. */ 524 maps__for_each_map(thread__maps(thread), thread__e_machine_callback, &args); 525 526 if (args.e_machine != EM_NONE) { 527 e_machine = args.e_machine; 528 local_e_flags = args.e_flags; 529 } else { 530 /* Maps failed, perhaps we're live with map events disabled. */ 531 bool is_live = machine->machines == NULL; 532 533 if (!is_live) { 534 /* Check if the session has a data file. */ 535 struct perf_session *session = container_of(machine->machines, 536 struct perf_session, 537 machines); 538 539 is_live = !!session->data; 540 } 541 /* Read from /proc/pid/exe if live. */ 542 if (is_live) { 543 e_machine = read_proc_e_machine_for_pid(pid, &local_e_flags, 544 &args.is_big_endian); 545 } else if (machine && machine->env) { 546 /* Offline analysis: fallback to environment metadata. */ 547 e_machine = perf_env__e_machine(machine->env, &local_e_flags); 548 args.is_big_endian = perf_arch_is_big_endian(perf_env__arch(machine->env)); 549 } 550 } 551 out: 552 if (e_machine != EM_NONE) { 553 thread__set_e_flags(thread, local_e_flags); 554 thread__set_e_is_big_endian(thread, args.is_big_endian); 555 thread__set_e_machine(thread, e_machine); 556 if (is_big_endian) 557 *is_big_endian = args.is_big_endian; 558 } else { 559 e_machine = EM_HOST; 560 local_e_flags = EF_HOST; 561 if (is_big_endian) 562 *is_big_endian = (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__); 563 } 564 if (e_flags) 565 *e_flags = local_e_flags; 566 return e_machine; 567 } 568 569 struct thread *thread__main_thread(struct machine *machine, struct thread *thread) 570 { 571 if (thread__pid(thread) == thread__tid(thread)) 572 return thread__get(thread); 573 574 if (thread__pid(thread) == -1) 575 return NULL; 576 577 return machine__find_thread(machine, thread__pid(thread), thread__pid(thread)); 578 } 579 580 int thread__memcpy(struct thread *thread, struct machine *machine, 581 void *buf, u64 ip, int len, bool *is64bit) 582 { 583 u8 cpumode = PERF_RECORD_MISC_USER; 584 struct addr_location al; 585 struct dso *dso; 586 long offset; 587 588 if (machine__kernel_ip(machine, ip)) 589 cpumode = PERF_RECORD_MISC_KERNEL; 590 591 addr_location__init(&al); 592 if (!thread__find_map(thread, cpumode, ip, &al)) { 593 addr_location__exit(&al); 594 return -1; 595 } 596 597 dso = map__dso(al.map); 598 599 if (!dso || dso__data(dso)->status == DSO_DATA_STATUS_ERROR || map__load(al.map) < 0) { 600 addr_location__exit(&al); 601 return -1; 602 } 603 604 offset = map__map_ip(al.map, ip); 605 if (is64bit) 606 *is64bit = dso__is_64_bit(dso); 607 608 addr_location__exit(&al); 609 610 return dso__data_read_offset(dso, machine, offset, buf, len); 611 } 612 613 void thread__free_stitch_list(struct thread *thread) 614 { 615 struct lbr_stitch *lbr_stitch = thread__lbr_stitch(thread); 616 struct stitch_list *pos, *tmp; 617 618 if (!lbr_stitch) 619 return; 620 621 list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) { 622 map_symbol__exit(&pos->cursor.ms); 623 list_del_init(&pos->node); 624 free(pos); 625 } 626 627 list_for_each_entry_safe(pos, tmp, &lbr_stitch->free_lists, node) { 628 list_del_init(&pos->node); 629 free(pos); 630 } 631 632 for (unsigned int i = 0 ; i < lbr_stitch->prev_lbr_cursor_size; i++) 633 map_symbol__exit(&lbr_stitch->prev_lbr_cursor[i].ms); 634 635 zfree(&lbr_stitch->prev_lbr_cursor); 636 free(thread__lbr_stitch(thread)); 637 thread__set_lbr_stitch(thread, NULL); 638 } 639