1// SPDX-License-Identifier: GPL-2.0
2#include <errno.h>
3#include <stdlib.h>
4#include <stdio.h>
5#include <string.h>
6#include <linux/kernel.h>
7#include <linux/zalloc.h>
8#include "dso.h"
9#include "session.h"
10#include "thread.h"
11#include "thread-stack.h"
12#include "debug.h"
13#include "namespaces.h"
14#include "comm.h"
15#include "map.h"
16#include "symbol.h"
17#include "unwind.h"
18#include "callchain.h"
19
20#include <api/fs/fs.h>
21
22int thread__init_maps(struct thread *thread, struct machine *machine)
23{
24 pid_t pid = thread__pid(thread);
25
26 if (pid == thread__tid(thread) || pid == -1) {
27 thread__set_maps(thread, maps: maps__new(machine));
28 } else {
29 struct thread *leader = machine__findnew_thread(machine, pid, tid: pid);
30
31 if (leader) {
32 thread__set_maps(thread, maps: maps__get(maps: thread__maps(thread: leader)));
33 thread__put(thread: leader);
34 }
35 }
36
37 return thread__maps(thread) ? 0 : -1;
38}
39
40struct thread *thread__new(pid_t pid, pid_t tid)
41{
42 char *comm_str;
43 struct comm *comm;
44 RC_STRUCT(thread) *_thread = zalloc(sizeof(*_thread));
45 struct thread *thread;
46
47 if (ADD_RC_CHK(thread, _thread) != NULL) {
48 thread__set_pid(thread, pid_: pid);
49 thread__set_tid(thread, tid);
50 thread__set_ppid(thread, ppid: -1);
51 thread__set_cpu(thread, cpu: -1);
52 thread__set_guest_cpu(thread, guest_cpu: -1);
53 thread__set_lbr_stitch_enable(thread, en: false);
54 INIT_LIST_HEAD(list: thread__namespaces_list(thread));
55 INIT_LIST_HEAD(list: thread__comm_list(thread));
56 init_rwsem(thread__namespaces_lock(thread));
57 init_rwsem(thread__comm_lock(thread));
58
59 comm_str = malloc(32);
60 if (!comm_str)
61 goto err_thread;
62
63 snprintf(buf: comm_str, size: 32, fmt: ":%d", tid);
64 comm = comm__new(str: comm_str, timestamp: 0, exec: false);
65 free(comm_str);
66 if (!comm)
67 goto err_thread;
68
69 list_add(new: &comm->list, head: thread__comm_list(thread));
70 refcount_set(r: thread__refcnt(thread), n: 1);
71 /* Thread holds first ref to nsdata. */
72 RC_CHK_ACCESS(thread)->nsinfo = nsinfo__new(pid);
73 srccode_state_init(state: thread__srccode_state(thread));
74 }
75
76 return thread;
77
78err_thread:
79 free(thread);
80 return NULL;
81}
82
83static void (*thread__priv_destructor)(void *priv);
84
85void thread__set_priv_destructor(void (*destructor)(void *priv))
86{
87 assert(thread__priv_destructor == NULL);
88
89 thread__priv_destructor = destructor;
90}
91
92void 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(maps: thread__maps(thread));
101 thread__set_maps(thread, NULL);
102 }
103 down_write(sem: thread__namespaces_lock(thread));
104 list_for_each_entry_safe(namespaces, tmp_namespaces,
105 thread__namespaces_list(thread), list) {
106 list_del_init(entry: &namespaces->list);
107 namespaces__free(namespaces);
108 }
109 up_write(sem: thread__namespaces_lock(thread));
110
111 down_write(sem: thread__comm_lock(thread));
112 list_for_each_entry_safe(comm, tmp_comm, thread__comm_list(thread), list) {
113 list_del_init(entry: &comm->list);
114 comm__free(comm);
115 }
116 up_write(sem: thread__comm_lock(thread));
117
118 nsinfo__zput(RC_CHK_ACCESS(thread)->nsinfo);
119 srccode_state_free(state: thread__srccode_state(thread));
120
121 exit_rwsem(sem: thread__namespaces_lock(thread));
122 exit_rwsem(sem: 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
131struct thread *thread__get(struct thread *thread)
132{
133 struct thread *result;
134
135 if (RC_CHK_GET(result, thread))
136 refcount_inc(r: thread__refcnt(thread));
137
138 return result;
139}
140
141void thread__put(struct thread *thread)
142{
143 if (thread && refcount_dec_and_test(r: thread__refcnt(thread)))
144 thread__delete(thread);
145 else
146 RC_CHK_PUT(thread);
147}
148
149static struct namespaces *__thread__namespaces(struct thread *thread)
150{
151 if (list_empty(head: thread__namespaces_list(thread)))
152 return NULL;
153
154 return list_first_entry(thread__namespaces_list(thread), struct namespaces, list);
155}
156
157struct namespaces *thread__namespaces(struct thread *thread)
158{
159 struct namespaces *ns;
160
161 down_read(sem: thread__namespaces_lock(thread));
162 ns = __thread__namespaces(thread);
163 up_read(sem: thread__namespaces_lock(thread));
164
165 return ns;
166}
167
168static 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: &new->list, head: 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
192int thread__set_namespaces(struct thread *thread, u64 timestamp,
193 struct perf_record_namespaces *event)
194{
195 int ret;
196
197 down_write(sem: thread__namespaces_lock(thread));
198 ret = __thread__set_namespaces(thread, timestamp, event);
199 up_write(sem: thread__namespaces_lock(thread));
200 return ret;
201}
202
203struct comm *thread__comm(struct thread *thread)
204{
205 if (list_empty(head: thread__comm_list(thread)))
206 return NULL;
207
208 return list_first_entry(thread__comm_list(thread), struct comm, list);
209}
210
211struct 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
234static 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(comm: 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: &new->list, head: thread__comm_list(thread));
249
250 if (exec)
251 unwind__flush_access(maps: thread__maps(thread));
252 }
253
254 thread__set_comm_set(thread, set: true);
255
256 return 0;
257}
258
259int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
260 bool exec)
261{
262 int ret;
263
264 down_write(sem: thread__comm_lock(thread));
265 ret = ____thread__set_comm(thread, str, timestamp, exec);
266 up_write(sem: thread__comm_lock(thread));
267 return ret;
268}
269
270int 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(buf: path, size: sizeof(path), fmt: "%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, timestamp: 0);
282 }
283
284 return err;
285}
286
287static 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
297const char *thread__comm_str(struct thread *thread)
298{
299 const char *str;
300
301 down_read(sem: thread__comm_lock(thread));
302 str = __thread__comm_str(thread);
303 up_read(sem: thread__comm_lock(thread));
304
305 return str;
306}
307
308static 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 */
318int 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(sem: thread__comm_lock(thread));
326 comm = __thread__comm_str(thread);
327 comm_len = __thread__comm_len(thread, comm);
328 up_read(sem: thread__comm_lock(thread));
329 }
330
331 return comm_len;
332}
333
334size_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
340int thread__insert_map(struct thread *thread, struct map *map)
341{
342 int ret;
343
344 ret = unwind__prepare_access(maps: thread__maps(thread), map, NULL);
345 if (ret)
346 return ret;
347
348 return maps__fixup_overlap_and_insert(maps: thread__maps(thread), new: map);
349}
350
351struct thread__prepare_access_maps_cb_args {
352 int err;
353 struct maps *maps;
354};
355
356static 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(maps: args->maps, map, initialized: &initialized);
362
363 return (args->err || initialized) ? 1 : 0;
364}
365
366static 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(maps: thread__maps(thread), cb: thread__prepare_access_maps_cb, data: &args);
375 }
376
377 return args.err;
378}
379
380static 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(thread: parent))
384 return thread__prepare_access(thread);
385
386 if (maps__equal(a: thread__maps(thread), b: thread__maps(thread: 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(maps: thread__maps(thread), parent: thread__maps(thread: parent)) : 0;
394}
395
396int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
397{
398 if (thread__comm_set(thread: parent)) {
399 const char *comm = thread__comm_str(thread: 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, ppid: thread__tid(thread: parent));
409 return thread__clone_maps(thread, parent, do_maps_clone);
410}
411
412void 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, cpumode: cpumodes[i], addr, al);
425 if (al->map)
426 break;
427 }
428}
429
430struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
431{
432 if (thread__pid(thread) == thread__tid(thread))
433 return thread__get(thread);
434
435 if (thread__pid(thread) == -1)
436 return NULL;
437
438 return machine__find_thread(machine, pid: thread__pid(thread), tid: thread__pid(thread));
439}
440
441int thread__memcpy(struct thread *thread, struct machine *machine,
442 void *buf, u64 ip, int len, bool *is64bit)
443{
444 u8 cpumode = PERF_RECORD_MISC_USER;
445 struct addr_location al;
446 struct dso *dso;
447 long offset;
448
449 if (machine__kernel_ip(machine, ip))
450 cpumode = PERF_RECORD_MISC_KERNEL;
451
452 addr_location__init(al: &al);
453 if (!thread__find_map(thread, cpumode, addr: ip, al: &al)) {
454 addr_location__exit(al: &al);
455 return -1;
456 }
457
458 dso = map__dso(map: al.map);
459
460 if (!dso || dso->data.status == DSO_DATA_STATUS_ERROR || map__load(map: al.map) < 0) {
461 addr_location__exit(al: &al);
462 return -1;
463 }
464
465 offset = map__map_ip(map: al.map, ip_or_rip: ip);
466 if (is64bit)
467 *is64bit = dso->is_64_bit;
468
469 addr_location__exit(al: &al);
470
471 return dso__data_read_offset(dso, machine, offset, data: buf, size: len);
472}
473
474void thread__free_stitch_list(struct thread *thread)
475{
476 struct lbr_stitch *lbr_stitch = thread__lbr_stitch(thread);
477 struct stitch_list *pos, *tmp;
478
479 if (!lbr_stitch)
480 return;
481
482 list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) {
483 list_del_init(entry: &pos->node);
484 free(pos);
485 }
486
487 list_for_each_entry_safe(pos, tmp, &lbr_stitch->free_lists, node) {
488 list_del_init(entry: &pos->node);
489 free(pos);
490 }
491
492 zfree(&lbr_stitch->prev_lbr_cursor);
493 free(thread__lbr_stitch(thread));
494 thread__set_lbr_stitch(thread, NULL);
495}
496

source code of linux/tools/perf/util/thread.c