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
thread__init_maps(struct thread * thread,struct machine * machine)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
thread__new(pid_t pid,pid_t tid)43 struct thread *thread__new(pid_t pid, pid_t tid)
44 {
45 RC_STRUCT(thread) *_thread = zalloc(sizeof(*_thread));
46 struct thread *thread;
47
48 if (ADD_RC_CHK(thread, _thread) != NULL) {
49 struct comm *comm;
50 char comm_str[32];
51
52 thread__set_pid(thread, pid);
53 thread__set_tid(thread, tid);
54 thread__set_ppid(thread, -1);
55 thread__set_cpu(thread, -1);
56 thread__set_guest_cpu(thread, -1);
57 thread__set_e_machine(thread, EM_NONE);
58 thread__set_lbr_stitch_enable(thread, false);
59 INIT_LIST_HEAD(thread__namespaces_list(thread));
60 INIT_LIST_HEAD(thread__comm_list(thread));
61 init_rwsem(thread__namespaces_lock(thread));
62 init_rwsem(thread__comm_lock(thread));
63
64 snprintf(comm_str, sizeof(comm_str), ":%d", tid);
65 comm = comm__new(comm_str, 0, false);
66 if (!comm)
67 goto err_thread;
68
69 list_add(&comm->list, thread__comm_list(thread));
70 refcount_set(thread__refcnt(thread), 1);
71 /* Thread holds first ref to nsdata. */
72 RC_CHK_ACCESS(thread)->nsinfo = nsinfo__new(pid);
73 srccode_state_init(thread__srccode_state(thread));
74 }
75
76 return thread;
77
78 err_thread:
79 thread__delete(thread);
80 return NULL;
81 }
82
83 static void (*thread__priv_destructor)(void *priv);
84
thread__set_priv_destructor(void (* destructor)(void * priv))85 void thread__set_priv_destructor(void (*destructor)(void *priv))
86 {
87 assert(thread__priv_destructor == NULL);
88
89 thread__priv_destructor = destructor;
90 }
91
thread__delete(struct thread * thread)92 void thread__delete(struct thread *thread)
93 {
94 struct namespaces *namespaces, *tmp_namespaces;
95 struct comm *comm, *tmp_comm;
96
97 thread_stack__free(thread);
98
99 if (thread__maps(thread)) {
100 maps__put(thread__maps(thread));
101 thread__set_maps(thread, NULL);
102 }
103 down_write(thread__namespaces_lock(thread));
104 list_for_each_entry_safe(namespaces, tmp_namespaces,
105 thread__namespaces_list(thread), list) {
106 list_del_init(&namespaces->list);
107 namespaces__free(namespaces);
108 }
109 up_write(thread__namespaces_lock(thread));
110
111 down_write(thread__comm_lock(thread));
112 list_for_each_entry_safe(comm, tmp_comm, thread__comm_list(thread), list) {
113 list_del_init(&comm->list);
114 comm__free(comm);
115 }
116 up_write(thread__comm_lock(thread));
117
118 nsinfo__zput(RC_CHK_ACCESS(thread)->nsinfo);
119 srccode_state_free(thread__srccode_state(thread));
120
121 exit_rwsem(thread__namespaces_lock(thread));
122 exit_rwsem(thread__comm_lock(thread));
123 thread__free_stitch_list(thread);
124
125 if (thread__priv_destructor)
126 thread__priv_destructor(thread__priv(thread));
127
128 RC_CHK_FREE(thread);
129 }
130
thread__get(struct thread * thread)131 struct thread *thread__get(struct thread *thread)
132 {
133 struct thread *result;
134
135 if (RC_CHK_GET(result, thread))
136 refcount_inc(thread__refcnt(thread));
137
138 return result;
139 }
140
thread__put(struct thread * thread)141 void thread__put(struct thread *thread)
142 {
143 if (thread && refcount_dec_and_test(thread__refcnt(thread)))
144 thread__delete(thread);
145 else
146 RC_CHK_PUT(thread);
147 }
148
__thread__namespaces(struct thread * thread)149 static struct namespaces *__thread__namespaces(struct thread *thread)
150 {
151 if (list_empty(thread__namespaces_list(thread)))
152 return NULL;
153
154 return list_first_entry(thread__namespaces_list(thread), struct namespaces, list);
155 }
156
thread__namespaces(struct thread * thread)157 struct namespaces *thread__namespaces(struct thread *thread)
158 {
159 struct namespaces *ns;
160
161 down_read(thread__namespaces_lock(thread));
162 ns = __thread__namespaces(thread);
163 up_read(thread__namespaces_lock(thread));
164
165 return ns;
166 }
167
__thread__set_namespaces(struct thread * thread,u64 timestamp,struct perf_record_namespaces * event)168 static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
169 struct perf_record_namespaces *event)
170 {
171 struct namespaces *new, *curr = __thread__namespaces(thread);
172
173 new = namespaces__new(event);
174 if (!new)
175 return -ENOMEM;
176
177 list_add(&new->list, thread__namespaces_list(thread));
178
179 if (timestamp && curr) {
180 /*
181 * setns syscall must have changed few or all the namespaces
182 * of this thread. Update end time for the namespaces
183 * previously used.
184 */
185 curr = list_next_entry(new, list);
186 curr->end_time = timestamp;
187 }
188
189 return 0;
190 }
191
thread__set_namespaces(struct thread * thread,u64 timestamp,struct perf_record_namespaces * event)192 int thread__set_namespaces(struct thread *thread, u64 timestamp,
193 struct perf_record_namespaces *event)
194 {
195 int ret;
196
197 down_write(thread__namespaces_lock(thread));
198 ret = __thread__set_namespaces(thread, timestamp, event);
199 up_write(thread__namespaces_lock(thread));
200 return ret;
201 }
202
thread__comm(struct thread * thread)203 struct comm *thread__comm(struct thread *thread)
204 {
205 if (list_empty(thread__comm_list(thread)))
206 return NULL;
207
208 return list_first_entry(thread__comm_list(thread), struct comm, list);
209 }
210
thread__exec_comm(struct thread * thread)211 struct comm *thread__exec_comm(struct thread *thread)
212 {
213 struct comm *comm, *last = NULL, *second_last = NULL;
214
215 list_for_each_entry(comm, thread__comm_list(thread), list) {
216 if (comm->exec)
217 return comm;
218 second_last = last;
219 last = comm;
220 }
221
222 /*
223 * 'last' with no start time might be the parent's comm of a synthesized
224 * thread (created by processing a synthesized fork event). For a main
225 * thread, that is very probably wrong. Prefer a later comm to avoid
226 * that case.
227 */
228 if (second_last && !last->start && thread__pid(thread) == thread__tid(thread))
229 return second_last;
230
231 return last;
232 }
233
____thread__set_comm(struct thread * thread,const char * str,u64 timestamp,bool exec)234 static int ____thread__set_comm(struct thread *thread, const char *str,
235 u64 timestamp, bool exec)
236 {
237 struct comm *new, *curr = thread__comm(thread);
238
239 /* Override the default :tid entry */
240 if (!thread__comm_set(thread)) {
241 int err = comm__override(curr, str, timestamp, exec);
242 if (err)
243 return err;
244 } else {
245 new = comm__new(str, timestamp, exec);
246 if (!new)
247 return -ENOMEM;
248 list_add(&new->list, thread__comm_list(thread));
249
250 if (exec)
251 unwind__flush_access(thread__maps(thread));
252 }
253
254 thread__set_comm_set(thread, true);
255
256 return 0;
257 }
258
__thread__set_comm(struct thread * thread,const char * str,u64 timestamp,bool exec)259 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
260 bool exec)
261 {
262 int ret;
263
264 down_write(thread__comm_lock(thread));
265 ret = ____thread__set_comm(thread, str, timestamp, exec);
266 up_write(thread__comm_lock(thread));
267 return ret;
268 }
269
thread__set_comm_from_proc(struct thread * thread)270 int thread__set_comm_from_proc(struct thread *thread)
271 {
272 char path[64];
273 char *comm = NULL;
274 size_t sz;
275 int err = -1;
276
277 if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
278 thread__pid(thread), thread__tid(thread)) >= (int)sizeof(path)) &&
279 procfs__read_str(path, &comm, &sz) == 0) {
280 comm[sz - 1] = '\0';
281 err = thread__set_comm(thread, comm, 0);
282 }
283
284 return err;
285 }
286
__thread__comm_str(struct thread * thread)287 static const char *__thread__comm_str(struct thread *thread)
288 {
289 const struct comm *comm = thread__comm(thread);
290
291 if (!comm)
292 return NULL;
293
294 return comm__str(comm);
295 }
296
thread__comm_str(struct thread * thread)297 const char *thread__comm_str(struct thread *thread)
298 {
299 const char *str;
300
301 down_read(thread__comm_lock(thread));
302 str = __thread__comm_str(thread);
303 up_read(thread__comm_lock(thread));
304
305 return str;
306 }
307
__thread__comm_len(struct thread * thread,const char * comm)308 static int __thread__comm_len(struct thread *thread, const char *comm)
309 {
310 if (!comm)
311 return 0;
312 thread__set_comm_len(thread, strlen(comm));
313
314 return thread__var_comm_len(thread);
315 }
316
317 /* CHECKME: it should probably better return the max comm len from its comm list */
thread__comm_len(struct thread * thread)318 int thread__comm_len(struct thread *thread)
319 {
320 int comm_len = thread__var_comm_len(thread);
321
322 if (!comm_len) {
323 const char *comm;
324
325 down_read(thread__comm_lock(thread));
326 comm = __thread__comm_str(thread);
327 comm_len = __thread__comm_len(thread, comm);
328 up_read(thread__comm_lock(thread));
329 }
330
331 return comm_len;
332 }
333
thread__fprintf(struct thread * thread,FILE * fp)334 size_t thread__fprintf(struct thread *thread, FILE *fp)
335 {
336 return fprintf(fp, "Thread %d %s\n", thread__tid(thread), thread__comm_str(thread)) +
337 maps__fprintf(thread__maps(thread), fp);
338 }
339
thread__insert_map(struct thread * thread,struct map * map)340 int thread__insert_map(struct thread *thread, struct map *map)
341 {
342 int ret;
343
344 ret = unwind__prepare_access(thread__maps(thread), map, NULL);
345 if (ret)
346 return ret;
347
348 return maps__fixup_overlap_and_insert(thread__maps(thread), map);
349 }
350
351 struct thread__prepare_access_maps_cb_args {
352 int err;
353 struct maps *maps;
354 };
355
thread__prepare_access_maps_cb(struct map * map,void * data)356 static int thread__prepare_access_maps_cb(struct map *map, void *data)
357 {
358 bool initialized = false;
359 struct thread__prepare_access_maps_cb_args *args = data;
360
361 args->err = unwind__prepare_access(args->maps, map, &initialized);
362
363 return (args->err || initialized) ? 1 : 0;
364 }
365
thread__prepare_access(struct thread * thread)366 static int thread__prepare_access(struct thread *thread)
367 {
368 struct thread__prepare_access_maps_cb_args args = {
369 .err = 0,
370 };
371
372 if (dwarf_callchain_users) {
373 args.maps = thread__maps(thread);
374 maps__for_each_map(thread__maps(thread), thread__prepare_access_maps_cb, &args);
375 }
376
377 return args.err;
378 }
379
thread__clone_maps(struct thread * thread,struct thread * parent,bool do_maps_clone)380 static int thread__clone_maps(struct thread *thread, struct thread *parent, bool do_maps_clone)
381 {
382 /* This is new thread, we share map groups for process. */
383 if (thread__pid(thread) == thread__pid(parent))
384 return thread__prepare_access(thread);
385
386 if (maps__equal(thread__maps(thread), thread__maps(parent))) {
387 pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
388 thread__pid(thread), thread__tid(thread),
389 thread__pid(parent), thread__tid(parent));
390 return 0;
391 }
392 /* But this one is new process, copy maps. */
393 return do_maps_clone ? maps__copy_from(thread__maps(thread), thread__maps(parent)) : 0;
394 }
395
thread__fork(struct thread * thread,struct thread * parent,u64 timestamp,bool do_maps_clone)396 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
397 {
398 if (thread__comm_set(parent)) {
399 const char *comm = thread__comm_str(parent);
400 int err;
401 if (!comm)
402 return -ENOMEM;
403 err = thread__set_comm(thread, comm, timestamp);
404 if (err)
405 return err;
406 }
407
408 thread__set_ppid(thread, thread__tid(parent));
409 return thread__clone_maps(thread, parent, do_maps_clone);
410 }
411
thread__find_cpumode_addr_location(struct thread * thread,u64 addr,struct addr_location * al)412 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
413 struct addr_location *al)
414 {
415 size_t i;
416 const u8 cpumodes[] = {
417 PERF_RECORD_MISC_USER,
418 PERF_RECORD_MISC_KERNEL,
419 PERF_RECORD_MISC_GUEST_USER,
420 PERF_RECORD_MISC_GUEST_KERNEL
421 };
422
423 for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
424 thread__find_symbol(thread, cpumodes[i], addr, al);
425 if (al->map)
426 break;
427 }
428 }
429
read_proc_e_machine_for_pid(pid_t pid)430 static uint16_t read_proc_e_machine_for_pid(pid_t pid)
431 {
432 char path[6 /* "/proc/" */ + 11 /* max length of pid */ + 5 /* "/exe\0" */];
433 int fd;
434 uint16_t e_machine = EM_NONE;
435
436 snprintf(path, sizeof(path), "/proc/%d/exe", pid);
437 fd = open(path, O_RDONLY);
438 if (fd >= 0) {
439 _Static_assert(offsetof(Elf32_Ehdr, e_machine) == 18, "Unexpected offset");
440 _Static_assert(offsetof(Elf64_Ehdr, e_machine) == 18, "Unexpected offset");
441 if (pread(fd, &e_machine, sizeof(e_machine), 18) != sizeof(e_machine))
442 e_machine = EM_NONE;
443 close(fd);
444 }
445 return e_machine;
446 }
447
thread__e_machine_callback(struct map * map,void * machine)448 static int thread__e_machine_callback(struct map *map, void *machine)
449 {
450 struct dso *dso = map__dso(map);
451
452 _Static_assert(0 == EM_NONE, "Unexpected EM_NONE");
453 if (!dso)
454 return EM_NONE;
455
456 return dso__e_machine(dso, machine);
457 }
458
thread__e_machine(struct thread * thread,struct machine * machine)459 uint16_t thread__e_machine(struct thread *thread, struct machine *machine)
460 {
461 pid_t tid, pid;
462 uint16_t e_machine = RC_CHK_ACCESS(thread)->e_machine;
463
464 if (e_machine != EM_NONE)
465 return e_machine;
466
467 tid = thread__tid(thread);
468 pid = thread__pid(thread);
469 if (pid != tid) {
470 struct thread *parent = machine__findnew_thread(machine, pid, pid);
471
472 if (parent) {
473 e_machine = thread__e_machine(parent, machine);
474 thread__set_e_machine(thread, e_machine);
475 return e_machine;
476 }
477 /* Something went wrong, fallback. */
478 }
479 /* Reading on the PID thread. First try to find from the maps. */
480 e_machine = maps__for_each_map(thread__maps(thread),
481 thread__e_machine_callback,
482 machine);
483 if (e_machine == EM_NONE) {
484 /* Maps failed, perhaps we're live with map events disabled. */
485 bool is_live = machine->machines == NULL;
486
487 if (!is_live) {
488 /* Check if the session has a data file. */
489 struct perf_session *session = container_of(machine->machines,
490 struct perf_session,
491 machines);
492
493 is_live = !!session->data;
494 }
495 /* Read from /proc/pid/exe if live. */
496 if (is_live)
497 e_machine = read_proc_e_machine_for_pid(pid);
498 }
499 if (e_machine != EM_NONE)
500 thread__set_e_machine(thread, e_machine);
501 else
502 e_machine = EM_HOST;
503 return e_machine;
504 }
505
thread__main_thread(struct machine * machine,struct thread * thread)506 struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
507 {
508 if (thread__pid(thread) == thread__tid(thread))
509 return thread__get(thread);
510
511 if (thread__pid(thread) == -1)
512 return NULL;
513
514 return machine__find_thread(machine, thread__pid(thread), thread__pid(thread));
515 }
516
thread__memcpy(struct thread * thread,struct machine * machine,void * buf,u64 ip,int len,bool * is64bit)517 int thread__memcpy(struct thread *thread, struct machine *machine,
518 void *buf, u64 ip, int len, bool *is64bit)
519 {
520 u8 cpumode = PERF_RECORD_MISC_USER;
521 struct addr_location al;
522 struct dso *dso;
523 long offset;
524
525 if (machine__kernel_ip(machine, ip))
526 cpumode = PERF_RECORD_MISC_KERNEL;
527
528 addr_location__init(&al);
529 if (!thread__find_map(thread, cpumode, ip, &al)) {
530 addr_location__exit(&al);
531 return -1;
532 }
533
534 dso = map__dso(al.map);
535
536 if (!dso || dso__data(dso)->status == DSO_DATA_STATUS_ERROR || map__load(al.map) < 0) {
537 addr_location__exit(&al);
538 return -1;
539 }
540
541 offset = map__map_ip(al.map, ip);
542 if (is64bit)
543 *is64bit = dso__is_64_bit(dso);
544
545 addr_location__exit(&al);
546
547 return dso__data_read_offset(dso, machine, offset, buf, len);
548 }
549
thread__free_stitch_list(struct thread * thread)550 void thread__free_stitch_list(struct thread *thread)
551 {
552 struct lbr_stitch *lbr_stitch = thread__lbr_stitch(thread);
553 struct stitch_list *pos, *tmp;
554
555 if (!lbr_stitch)
556 return;
557
558 list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) {
559 map_symbol__exit(&pos->cursor.ms);
560 list_del_init(&pos->node);
561 free(pos);
562 }
563
564 list_for_each_entry_safe(pos, tmp, &lbr_stitch->free_lists, node) {
565 list_del_init(&pos->node);
566 free(pos);
567 }
568
569 for (unsigned int i = 0 ; i < lbr_stitch->prev_lbr_cursor_size; i++)
570 map_symbol__exit(&lbr_stitch->prev_lbr_cursor[i].ms);
571
572 zfree(&lbr_stitch->prev_lbr_cursor);
573 free(thread__lbr_stitch(thread));
574 thread__set_lbr_stitch(thread, NULL);
575 }
576