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 comm[sz - 1] = '\0'; 299 err = thread__set_comm(thread, comm, 0); 300 } 301 302 return err; 303 } 304 305 static const char *__thread__comm_str(struct thread *thread) 306 SHARED_LOCKS_REQUIRED(thread__comm_lock(thread)) 307 { 308 const struct comm *comm = __thread__comm(thread); 309 310 if (!comm) 311 return NULL; 312 313 return comm__str(comm); 314 } 315 316 const char *thread__comm_str(struct thread *thread) 317 { 318 const char *str; 319 320 down_read(thread__comm_lock(thread)); 321 str = __thread__comm_str(thread); 322 up_read(thread__comm_lock(thread)); 323 324 return str; 325 } 326 327 static int __thread__comm_len(struct thread *thread, const char *comm) 328 { 329 if (!comm) 330 return 0; 331 thread__set_comm_len(thread, strlen(comm)); 332 333 return thread__var_comm_len(thread); 334 } 335 336 /* CHECKME: it should probably better return the max comm len from its comm list */ 337 int thread__comm_len(struct thread *thread) 338 { 339 int comm_len = thread__var_comm_len(thread); 340 341 if (!comm_len) { 342 const char *comm; 343 344 down_read(thread__comm_lock(thread)); 345 comm = __thread__comm_str(thread); 346 comm_len = __thread__comm_len(thread, comm); 347 up_read(thread__comm_lock(thread)); 348 } 349 350 return comm_len; 351 } 352 353 size_t thread__fprintf(struct thread *thread, FILE *fp) 354 { 355 return fprintf(fp, "Thread %d %s\n", thread__tid(thread), thread__comm_str(thread)) + 356 maps__fprintf(thread__maps(thread), fp); 357 } 358 359 int thread__insert_map(struct thread *thread, struct map *map) 360 { 361 int ret; 362 uint16_t e_machine; 363 364 ret = maps__fixup_overlap_and_insert(thread__maps(thread), map); 365 if (ret) 366 return ret; 367 368 e_machine = thread__e_machine(thread, /*machine=*/NULL, /*e_flags=*/NULL); 369 return unwind__prepare_access(thread__maps(thread), e_machine); 370 } 371 372 static int thread__prepare_access(struct thread *thread) 373 { 374 uint16_t e_machine = thread__e_machine(thread, /*machine=*/NULL, /*e_flags=*/NULL); 375 376 return unwind__prepare_access(thread__maps(thread), e_machine); 377 } 378 379 static int thread__clone_maps(struct thread *thread, struct thread *parent, bool do_maps_clone) 380 { 381 /* This is new thread, we share map groups for process. */ 382 if (thread__pid(thread) == thread__pid(parent)) 383 return thread__prepare_access(thread); 384 385 if (maps__equal(thread__maps(thread), thread__maps(parent))) { 386 pr_debug("broken map groups on thread %d/%d parent %d/%d\n", 387 thread__pid(thread), thread__tid(thread), 388 thread__pid(parent), thread__tid(parent)); 389 return 0; 390 } 391 /* But this one is new process, copy maps. */ 392 return do_maps_clone ? maps__copy_from(thread__maps(thread), thread__maps(parent)) : 0; 393 } 394 395 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone) 396 { 397 if (thread__comm_set(parent)) { 398 const char *comm = thread__comm_str(parent); 399 int err; 400 if (!comm) 401 return -ENOMEM; 402 err = thread__set_comm(thread, comm, timestamp); 403 if (err) 404 return err; 405 } 406 407 thread__set_ppid(thread, thread__tid(parent)); 408 return thread__clone_maps(thread, parent, do_maps_clone); 409 } 410 411 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr, 412 bool symbols, struct addr_location *al) 413 { 414 size_t i; 415 const u8 cpumodes[] = { 416 PERF_RECORD_MISC_USER, 417 PERF_RECORD_MISC_KERNEL, 418 PERF_RECORD_MISC_GUEST_USER, 419 PERF_RECORD_MISC_GUEST_KERNEL 420 }; 421 422 for (i = 0; i < ARRAY_SIZE(cpumodes); i++) { 423 if (symbols) 424 thread__find_symbol(thread, cpumodes[i], addr, al); 425 else 426 thread__find_map(thread, cpumodes[i], addr, al); 427 428 if (al->map) 429 break; 430 } 431 } 432 433 static uint16_t read_proc_e_machine_for_pid(pid_t pid, uint32_t *e_flags, bool *is_big_endian) 434 { 435 char path[6 /* "/proc/" */ + 11 /* max length of pid */ + 5 /* "/exe\0" */]; 436 int fd; 437 uint16_t e_machine = EM_NONE; 438 439 snprintf(path, sizeof(path), "/proc/%d/exe", pid); 440 fd = open(path, O_RDONLY); 441 if (fd >= 0) { 442 e_machine = dso__read_e_machine_endian(/*optional_dso=*/NULL, fd, e_flags, 443 is_big_endian); 444 close(fd); 445 } 446 return e_machine; 447 } 448 449 struct thread__e_machine_callback_args { 450 struct machine *machine; 451 uint32_t e_flags; 452 uint16_t e_machine; 453 bool is_big_endian; 454 }; 455 456 static int thread__e_machine_callback(struct map *map, void *_args) 457 { 458 struct thread__e_machine_callback_args *args = _args; 459 struct dso *dso = map__dso(map); 460 461 if (!dso) 462 return 0; // No dso, continue search. 463 464 args->e_machine = 465 dso__e_machine_endian(dso, args->machine, &args->e_flags, &args->is_big_endian); 466 return args->e_machine != EM_NONE ? 1 /* stop search */ : 0 /* continue search */; 467 } 468 469 uint16_t thread__e_machine_endian(struct thread *thread, struct machine *machine, uint32_t *e_flags, 470 bool *is_big_endian) 471 { 472 pid_t tid, pid; 473 uint16_t e_machine; 474 uint32_t local_e_flags = 0; 475 struct thread__e_machine_callback_args args; 476 477 if (!thread) { 478 if (is_big_endian) { 479 *is_big_endian = perf_arch_is_big_endian( 480 machine && machine->env ? perf_env__arch(machine->env) : NULL); 481 } 482 return perf_env__e_machine(machine ? machine->env : NULL, e_flags); 483 } 484 485 e_machine = RC_CHK_ACCESS(thread)->e_machine; 486 args.machine = machine; 487 args.e_flags = 0; 488 args.e_machine = EM_NONE; 489 args.is_big_endian = false; 490 491 if (e_machine != EM_NONE) { 492 if (e_flags) 493 *e_flags = thread__e_flags(thread); 494 if (is_big_endian) 495 *is_big_endian = thread__e_is_big_endian(thread); 496 return e_machine; 497 } 498 499 if (machine == NULL) { 500 struct maps *maps = thread__maps(thread); 501 502 machine = maps__machine(maps); 503 args.machine = machine; 504 } 505 tid = thread__tid(thread); 506 pid = thread__pid(thread); 507 if (pid != tid) { 508 struct thread *parent = machine__findnew_thread(machine, pid, pid); 509 510 if (parent) { 511 e_machine = thread__e_machine_endian(parent, machine, &local_e_flags, 512 &args.is_big_endian); 513 thread__put(parent); 514 goto out; 515 } 516 /* Something went wrong, fallback. */ 517 } 518 /* Reading on the PID thread. First try to find from the maps. */ 519 maps__for_each_map(thread__maps(thread), thread__e_machine_callback, &args); 520 521 if (args.e_machine != EM_NONE) { 522 e_machine = args.e_machine; 523 local_e_flags = args.e_flags; 524 } else { 525 /* Maps failed, perhaps we're live with map events disabled. */ 526 bool is_live = machine->machines == NULL; 527 528 if (!is_live) { 529 /* Check if the session has a data file. */ 530 struct perf_session *session = container_of(machine->machines, 531 struct perf_session, 532 machines); 533 534 is_live = !!session->data; 535 } 536 /* Read from /proc/pid/exe if live. */ 537 if (is_live) { 538 e_machine = read_proc_e_machine_for_pid(pid, &local_e_flags, 539 &args.is_big_endian); 540 } else if (machine && machine->env) { 541 /* Offline analysis: fallback to environment metadata. */ 542 e_machine = perf_env__e_machine(machine->env, &local_e_flags); 543 args.is_big_endian = perf_arch_is_big_endian(perf_env__arch(machine->env)); 544 } 545 } 546 out: 547 if (e_machine != EM_NONE) { 548 thread__set_e_flags(thread, local_e_flags); 549 thread__set_e_is_big_endian(thread, args.is_big_endian); 550 thread__set_e_machine(thread, e_machine); 551 if (is_big_endian) 552 *is_big_endian = args.is_big_endian; 553 } else { 554 e_machine = EM_HOST; 555 local_e_flags = EF_HOST; 556 if (is_big_endian) 557 *is_big_endian = (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__); 558 } 559 if (e_flags) 560 *e_flags = local_e_flags; 561 return e_machine; 562 } 563 564 struct thread *thread__main_thread(struct machine *machine, struct thread *thread) 565 { 566 if (thread__pid(thread) == thread__tid(thread)) 567 return thread__get(thread); 568 569 if (thread__pid(thread) == -1) 570 return NULL; 571 572 return machine__find_thread(machine, thread__pid(thread), thread__pid(thread)); 573 } 574 575 int thread__memcpy(struct thread *thread, struct machine *machine, 576 void *buf, u64 ip, int len, bool *is64bit) 577 { 578 u8 cpumode = PERF_RECORD_MISC_USER; 579 struct addr_location al; 580 struct dso *dso; 581 long offset; 582 583 if (machine__kernel_ip(machine, ip)) 584 cpumode = PERF_RECORD_MISC_KERNEL; 585 586 addr_location__init(&al); 587 if (!thread__find_map(thread, cpumode, ip, &al)) { 588 addr_location__exit(&al); 589 return -1; 590 } 591 592 dso = map__dso(al.map); 593 594 if (!dso || dso__data(dso)->status == DSO_DATA_STATUS_ERROR || map__load(al.map) < 0) { 595 addr_location__exit(&al); 596 return -1; 597 } 598 599 offset = map__map_ip(al.map, ip); 600 if (is64bit) 601 *is64bit = dso__is_64_bit(dso); 602 603 addr_location__exit(&al); 604 605 return dso__data_read_offset(dso, machine, offset, buf, len); 606 } 607 608 void thread__free_stitch_list(struct thread *thread) 609 { 610 struct lbr_stitch *lbr_stitch = thread__lbr_stitch(thread); 611 struct stitch_list *pos, *tmp; 612 613 if (!lbr_stitch) 614 return; 615 616 list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) { 617 map_symbol__exit(&pos->cursor.ms); 618 list_del_init(&pos->node); 619 free(pos); 620 } 621 622 list_for_each_entry_safe(pos, tmp, &lbr_stitch->free_lists, node) { 623 list_del_init(&pos->node); 624 free(pos); 625 } 626 627 for (unsigned int i = 0 ; i < lbr_stitch->prev_lbr_cursor_size; i++) 628 map_symbol__exit(&lbr_stitch->prev_lbr_cursor[i].ms); 629 630 zfree(&lbr_stitch->prev_lbr_cursor); 631 free(thread__lbr_stitch(thread)); 632 thread__set_lbr_stitch(thread, NULL); 633 } 634