GNU Linux-libre 4.19.211-gnu1
[releases.git] / tools / perf / util / thread.c
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
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
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
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
112 struct thread *thread__get(struct thread *thread)
113 {
114         if (thread)
115                 refcount_inc(&thread->refcnt);
116         return thread;
117 }
118
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
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
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
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
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
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
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
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
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
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
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
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 */
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
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
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
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
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
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
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
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
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 }