1 // SPDX-License-Identifier: GPL-2.0
2 #include "../perf.h"
3 #include <errno.h>
4 #include <stdlib.h>
5 #include <stdio.h>
6 #include <string.h>
7 #include <linux/kernel.h>
8 #include "session.h"
9 #include "thread.h"
10 #include "thread-stack.h"
11 #include "util.h"
12 #include "debug.h"
13 #include "namespaces.h"
14 #include "comm.h"
15 #include "unwind.h"
16
17 #include <api/fs/fs.h>
18
thread__init_map_groups(struct thread * thread,struct machine * machine)19 int thread__init_map_groups(struct thread *thread, struct machine *machine)
20 {
21 pid_t pid = thread->pid_;
22
23 if (pid == thread->tid || pid == -1) {
24 thread->mg = map_groups__new(machine);
25 } else {
26 struct thread *leader = __machine__findnew_thread(machine, pid, pid);
27 if (leader) {
28 thread->mg = map_groups__get(leader->mg);
29 thread__put(leader);
30 }
31 }
32
33 return thread->mg ? 0 : -1;
34 }
35
thread__new(pid_t pid,pid_t tid)36 struct thread *thread__new(pid_t pid, pid_t tid)
37 {
38 char *comm_str;
39 struct comm *comm;
40 struct thread *thread = zalloc(sizeof(*thread));
41
42 if (thread != NULL) {
43 thread->pid_ = pid;
44 thread->tid = tid;
45 thread->ppid = -1;
46 thread->cpu = -1;
47 INIT_LIST_HEAD(&thread->namespaces_list);
48 INIT_LIST_HEAD(&thread->comm_list);
49 init_rwsem(&thread->namespaces_lock);
50 init_rwsem(&thread->comm_lock);
51
52 comm_str = malloc(32);
53 if (!comm_str)
54 goto err_thread;
55
56 snprintf(comm_str, 32, ":%d", tid);
57 comm = comm__new(comm_str, 0, false);
58 free(comm_str);
59 if (!comm)
60 goto err_thread;
61
62 list_add(&comm->list, &thread->comm_list);
63 refcount_set(&thread->refcnt, 1);
64 RB_CLEAR_NODE(&thread->rb_node);
65 /* Thread holds first ref to nsdata. */
66 thread->nsinfo = nsinfo__new(pid);
67 }
68
69 return thread;
70
71 err_thread:
72 free(thread);
73 return NULL;
74 }
75
thread__delete(struct thread * thread)76 void thread__delete(struct thread *thread)
77 {
78 struct namespaces *namespaces, *tmp_namespaces;
79 struct comm *comm, *tmp_comm;
80
81 BUG_ON(!RB_EMPTY_NODE(&thread->rb_node));
82
83 thread_stack__free(thread);
84
85 if (thread->mg) {
86 map_groups__put(thread->mg);
87 thread->mg = NULL;
88 }
89 down_write(&thread->namespaces_lock);
90 list_for_each_entry_safe(namespaces, tmp_namespaces,
91 &thread->namespaces_list, list) {
92 list_del(&namespaces->list);
93 namespaces__free(namespaces);
94 }
95 up_write(&thread->namespaces_lock);
96
97 down_write(&thread->comm_lock);
98 list_for_each_entry_safe(comm, tmp_comm, &thread->comm_list, list) {
99 list_del(&comm->list);
100 comm__free(comm);
101 }
102 up_write(&thread->comm_lock);
103
104 unwind__finish_access(thread);
105 nsinfo__zput(thread->nsinfo);
106
107 exit_rwsem(&thread->namespaces_lock);
108 exit_rwsem(&thread->comm_lock);
109 free(thread);
110 }
111
thread__get(struct thread * thread)112 struct thread *thread__get(struct thread *thread)
113 {
114 if (thread)
115 refcount_inc(&thread->refcnt);
116 return thread;
117 }
118
thread__put(struct thread * thread)119 void thread__put(struct thread *thread)
120 {
121 if (thread && refcount_dec_and_test(&thread->refcnt)) {
122 /*
123 * Remove it from the dead_threads list, as last reference
124 * is gone.
125 */
126 list_del_init(&thread->node);
127 thread__delete(thread);
128 }
129 }
130
__thread__namespaces(const struct thread * thread)131 static struct namespaces *__thread__namespaces(const struct thread *thread)
132 {
133 if (list_empty(&thread->namespaces_list))
134 return NULL;
135
136 return list_first_entry(&thread->namespaces_list, struct namespaces, list);
137 }
138
thread__namespaces(const struct thread * thread)139 struct namespaces *thread__namespaces(const struct thread *thread)
140 {
141 struct namespaces *ns;
142
143 down_read((struct rw_semaphore *)&thread->namespaces_lock);
144 ns = __thread__namespaces(thread);
145 up_read((struct rw_semaphore *)&thread->namespaces_lock);
146
147 return ns;
148 }
149
__thread__set_namespaces(struct thread * thread,u64 timestamp,struct namespaces_event * event)150 static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
151 struct namespaces_event *event)
152 {
153 struct namespaces *new, *curr = __thread__namespaces(thread);
154
155 new = namespaces__new(event);
156 if (!new)
157 return -ENOMEM;
158
159 list_add(&new->list, &thread->namespaces_list);
160
161 if (timestamp && curr) {
162 /*
163 * setns syscall must have changed few or all the namespaces
164 * of this thread. Update end time for the namespaces
165 * previously used.
166 */
167 curr = list_next_entry(new, list);
168 curr->end_time = timestamp;
169 }
170
171 return 0;
172 }
173
thread__set_namespaces(struct thread * thread,u64 timestamp,struct namespaces_event * event)174 int thread__set_namespaces(struct thread *thread, u64 timestamp,
175 struct namespaces_event *event)
176 {
177 int ret;
178
179 down_write(&thread->namespaces_lock);
180 ret = __thread__set_namespaces(thread, timestamp, event);
181 up_write(&thread->namespaces_lock);
182 return ret;
183 }
184
thread__comm(const struct thread * thread)185 struct comm *thread__comm(const struct thread *thread)
186 {
187 if (list_empty(&thread->comm_list))
188 return NULL;
189
190 return list_first_entry(&thread->comm_list, struct comm, list);
191 }
192
thread__exec_comm(const struct thread * thread)193 struct comm *thread__exec_comm(const struct thread *thread)
194 {
195 struct comm *comm, *last = NULL, *second_last = NULL;
196
197 list_for_each_entry(comm, &thread->comm_list, list) {
198 if (comm->exec)
199 return comm;
200 second_last = last;
201 last = comm;
202 }
203
204 /*
205 * 'last' with no start time might be the parent's comm of a synthesized
206 * thread (created by processing a synthesized fork event). For a main
207 * thread, that is very probably wrong. Prefer a later comm to avoid
208 * that case.
209 */
210 if (second_last && !last->start && thread->pid_ == thread->tid)
211 return second_last;
212
213 return last;
214 }
215
____thread__set_comm(struct thread * thread,const char * str,u64 timestamp,bool exec)216 static int ____thread__set_comm(struct thread *thread, const char *str,
217 u64 timestamp, bool exec)
218 {
219 struct comm *new, *curr = thread__comm(thread);
220
221 /* Override the default :tid entry */
222 if (!thread->comm_set) {
223 int err = comm__override(curr, str, timestamp, exec);
224 if (err)
225 return err;
226 } else {
227 new = comm__new(str, timestamp, exec);
228 if (!new)
229 return -ENOMEM;
230 list_add(&new->list, &thread->comm_list);
231
232 if (exec)
233 unwind__flush_access(thread);
234 }
235
236 thread->comm_set = true;
237
238 return 0;
239 }
240
__thread__set_comm(struct thread * thread,const char * str,u64 timestamp,bool exec)241 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
242 bool exec)
243 {
244 int ret;
245
246 down_write(&thread->comm_lock);
247 ret = ____thread__set_comm(thread, str, timestamp, exec);
248 up_write(&thread->comm_lock);
249 return ret;
250 }
251
thread__set_comm_from_proc(struct thread * thread)252 int thread__set_comm_from_proc(struct thread *thread)
253 {
254 char path[64];
255 char *comm = NULL;
256 size_t sz;
257 int err = -1;
258
259 if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
260 thread->pid_, thread->tid) >= (int)sizeof(path)) &&
261 procfs__read_str(path, &comm, &sz) == 0) {
262 comm[sz - 1] = '\0';
263 err = thread__set_comm(thread, comm, 0);
264 }
265
266 return err;
267 }
268
__thread__comm_str(const struct thread * thread)269 static const char *__thread__comm_str(const struct thread *thread)
270 {
271 const struct comm *comm = thread__comm(thread);
272
273 if (!comm)
274 return NULL;
275
276 return comm__str(comm);
277 }
278
thread__comm_str(const struct thread * thread)279 const char *thread__comm_str(const struct thread *thread)
280 {
281 const char *str;
282
283 down_read((struct rw_semaphore *)&thread->comm_lock);
284 str = __thread__comm_str(thread);
285 up_read((struct rw_semaphore *)&thread->comm_lock);
286
287 return str;
288 }
289
290 /* CHECKME: it should probably better return the max comm len from its comm list */
thread__comm_len(struct thread * thread)291 int thread__comm_len(struct thread *thread)
292 {
293 if (!thread->comm_len) {
294 const char *comm = thread__comm_str(thread);
295 if (!comm)
296 return 0;
297 thread->comm_len = strlen(comm);
298 }
299
300 return thread->comm_len;
301 }
302
thread__fprintf(struct thread * thread,FILE * fp)303 size_t thread__fprintf(struct thread *thread, FILE *fp)
304 {
305 return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) +
306 map_groups__fprintf(thread->mg, fp);
307 }
308
thread__insert_map(struct thread * thread,struct map * map)309 int thread__insert_map(struct thread *thread, struct map *map)
310 {
311 int ret;
312
313 ret = unwind__prepare_access(thread, map, NULL);
314 if (ret)
315 return ret;
316
317 map_groups__fixup_overlappings(thread->mg, map, stderr);
318 map_groups__insert(thread->mg, map);
319
320 return 0;
321 }
322
__thread__prepare_access(struct thread * thread)323 static int __thread__prepare_access(struct thread *thread)
324 {
325 bool initialized = false;
326 int err = 0;
327 struct maps *maps = &thread->mg->maps;
328 struct map *map;
329
330 down_read(&maps->lock);
331
332 for (map = maps__first(maps); map; map = map__next(map)) {
333 err = unwind__prepare_access(thread, map, &initialized);
334 if (err || initialized)
335 break;
336 }
337
338 up_read(&maps->lock);
339
340 return err;
341 }
342
thread__prepare_access(struct thread * thread)343 static int thread__prepare_access(struct thread *thread)
344 {
345 int err = 0;
346
347 if (symbol_conf.use_callchain)
348 err = __thread__prepare_access(thread);
349
350 return err;
351 }
352
thread__clone_map_groups(struct thread * thread,struct thread * parent)353 static int thread__clone_map_groups(struct thread *thread,
354 struct thread *parent)
355 {
356 /* This is new thread, we share map groups for process. */
357 if (thread->pid_ == parent->pid_)
358 return thread__prepare_access(thread);
359
360 if (thread->mg == parent->mg) {
361 pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
362 thread->pid_, thread->tid, parent->pid_, parent->tid);
363 return 0;
364 }
365
366 /* But this one is new process, copy maps. */
367 if (map_groups__clone(thread, parent->mg) < 0)
368 return -ENOMEM;
369
370 return 0;
371 }
372
thread__fork(struct thread * thread,struct thread * parent,u64 timestamp)373 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
374 {
375 if (parent->comm_set) {
376 const char *comm = thread__comm_str(parent);
377 int err;
378 if (!comm)
379 return -ENOMEM;
380 err = thread__set_comm(thread, comm, timestamp);
381 if (err)
382 return err;
383 }
384
385 thread->ppid = parent->tid;
386 return thread__clone_map_groups(thread, parent);
387 }
388
thread__find_cpumode_addr_location(struct thread * thread,u64 addr,struct addr_location * al)389 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
390 struct addr_location *al)
391 {
392 size_t i;
393 const u8 cpumodes[] = {
394 PERF_RECORD_MISC_USER,
395 PERF_RECORD_MISC_KERNEL,
396 PERF_RECORD_MISC_GUEST_USER,
397 PERF_RECORD_MISC_GUEST_KERNEL
398 };
399
400 for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
401 thread__find_symbol(thread, cpumodes[i], addr, al);
402 if (al->map)
403 break;
404 }
405 }
406
thread__main_thread(struct machine * machine,struct thread * thread)407 struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
408 {
409 if (thread->pid_ == thread->tid)
410 return thread__get(thread);
411
412 if (thread->pid_ == -1)
413 return NULL;
414
415 return machine__find_thread(machine, thread->pid_, thread->pid_);
416 }
417