xref: /linux-6.15/tools/perf/util/thread_map.c (revision faaf9567) 
1 // SPDX-License-Identifier: GPL-2.0
2 #include <dirent.h>
3 #include <errno.h>
4 #include <limits.h>
5 #include <stdbool.h>
6 #include <stdlib.h>
7 #include <stdio.h>
8 #include <sys/types.h>
9 #include <sys/stat.h>
10 #include <unistd.h>
11 #include "string2.h"
12 #include "strlist.h"
13 #include <string.h>
14 #include <api/fs/fs.h>
15 #include "asm/bug.h"
16 #include "thread_map.h"
17 #include "util.h"
18 #include "debug.h"
19 #include "event.h"
20 
21 /* Skip "." and ".." directories */
22 static int filter(const struct dirent *dir)
23 {
24 	if (dir->d_name[0] == '.')
25 		return 0;
26 	else
27 		return 1;
28 }
29 
30 static void thread_map__reset(struct thread_map *map, int start, int nr)
31 {
32 	size_t size = (nr - start) * sizeof(map->map[0]);
33 
34 	memset(&map->map[start], 0, size);
35 }
36 
37 static struct thread_map *thread_map__realloc(struct thread_map *map, int nr)
38 {
39 	size_t size = sizeof(*map) + sizeof(map->map[0]) * nr;
40 	int start = map ? map->nr : 0;
41 
42 	map = realloc(map, size);
43 	/*
44 	 * We only realloc to add more items, let's reset new items.
45 	 */
46 	if (map)
47 		thread_map__reset(map, start, nr);
48 
49 	return map;
50 }
51 
52 #define thread_map__alloc(__nr) thread_map__realloc(NULL, __nr)
53 
54 struct thread_map *thread_map__new_by_pid(pid_t pid)
55 {
56 	struct thread_map *threads;
57 	char name[256];
58 	int items;
59 	struct dirent **namelist = NULL;
60 	int i;
61 
62 	sprintf(name, "/proc/%d/task", pid);
63 	items = scandir(name, &namelist, filter, NULL);
64 	if (items <= 0)
65 		return NULL;
66 
67 	threads = thread_map__alloc(items);
68 	if (threads != NULL) {
69 		for (i = 0; i < items; i++)
70 			thread_map__set_pid(threads, i, atoi(namelist[i]->d_name));
71 		threads->nr = items;
72 		refcount_set(&threads->refcnt, 1);
73 	}
74 
75 	for (i=0; i<items; i++)
76 		zfree(&namelist[i]);
77 	free(namelist);
78 
79 	return threads;
80 }
81 
82 struct thread_map *thread_map__new_by_tid(pid_t tid)
83 {
84 	struct thread_map *threads = thread_map__alloc(1);
85 
86 	if (threads != NULL) {
87 		thread_map__set_pid(threads, 0, tid);
88 		threads->nr = 1;
89 		refcount_set(&threads->refcnt, 1);
90 	}
91 
92 	return threads;
93 }
94 
95 static struct thread_map *__thread_map__new_all_cpus(uid_t uid)
96 {
97 	DIR *proc;
98 	int max_threads = 32, items, i;
99 	char path[NAME_MAX + 1 + 6];
100 	struct dirent *dirent, **namelist = NULL;
101 	struct thread_map *threads = thread_map__alloc(max_threads);
102 
103 	if (threads == NULL)
104 		goto out;
105 
106 	proc = opendir("/proc");
107 	if (proc == NULL)
108 		goto out_free_threads;
109 
110 	threads->nr = 0;
111 	refcount_set(&threads->refcnt, 1);
112 
113 	while ((dirent = readdir(proc)) != NULL) {
114 		char *end;
115 		bool grow = false;
116 		pid_t pid = strtol(dirent->d_name, &end, 10);
117 
118 		if (*end) /* only interested in proper numerical dirents */
119 			continue;
120 
121 		snprintf(path, sizeof(path), "/proc/%s", dirent->d_name);
122 
123 		if (uid != UINT_MAX) {
124 			struct stat st;
125 
126 			if (stat(path, &st) != 0 || st.st_uid != uid)
127 				continue;
128 		}
129 
130 		snprintf(path, sizeof(path), "/proc/%d/task", pid);
131 		items = scandir(path, &namelist, filter, NULL);
132 		if (items <= 0)
133 			goto out_free_closedir;
134 
135 		while (threads->nr + items >= max_threads) {
136 			max_threads *= 2;
137 			grow = true;
138 		}
139 
140 		if (grow) {
141 			struct thread_map *tmp;
142 
143 			tmp = thread_map__realloc(threads, max_threads);
144 			if (tmp == NULL)
145 				goto out_free_namelist;
146 
147 			threads = tmp;
148 		}
149 
150 		for (i = 0; i < items; i++) {
151 			thread_map__set_pid(threads, threads->nr + i,
152 					    atoi(namelist[i]->d_name));
153 		}
154 
155 		for (i = 0; i < items; i++)
156 			zfree(&namelist[i]);
157 		free(namelist);
158 
159 		threads->nr += items;
160 	}
161 
162 out_closedir:
163 	closedir(proc);
164 out:
165 	return threads;
166 
167 out_free_threads:
168 	free(threads);
169 	return NULL;
170 
171 out_free_namelist:
172 	for (i = 0; i < items; i++)
173 		zfree(&namelist[i]);
174 	free(namelist);
175 
176 out_free_closedir:
177 	zfree(&threads);
178 	goto out_closedir;
179 }
180 
181 struct thread_map *thread_map__new_all_cpus(void)
182 {
183 	return __thread_map__new_all_cpus(UINT_MAX);
184 }
185 
186 struct thread_map *thread_map__new_by_uid(uid_t uid)
187 {
188 	return __thread_map__new_all_cpus(uid);
189 }
190 
191 struct thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid)
192 {
193 	if (pid != -1)
194 		return thread_map__new_by_pid(pid);
195 
196 	if (tid == -1 && uid != UINT_MAX)
197 		return thread_map__new_by_uid(uid);
198 
199 	return thread_map__new_by_tid(tid);
200 }
201 
202 static struct thread_map *thread_map__new_by_pid_str(const char *pid_str)
203 {
204 	struct thread_map *threads = NULL, *nt;
205 	char name[256];
206 	int items, total_tasks = 0;
207 	struct dirent **namelist = NULL;
208 	int i, j = 0;
209 	pid_t pid, prev_pid = INT_MAX;
210 	char *end_ptr;
211 	struct str_node *pos;
212 	struct strlist_config slist_config = { .dont_dupstr = true, };
213 	struct strlist *slist = strlist__new(pid_str, &slist_config);
214 
215 	if (!slist)
216 		return NULL;
217 
218 	strlist__for_each_entry(pos, slist) {
219 		pid = strtol(pos->s, &end_ptr, 10);
220 
221 		if (pid == INT_MIN || pid == INT_MAX ||
222 		    (*end_ptr != '\0' && *end_ptr != ','))
223 			goto out_free_threads;
224 
225 		if (pid == prev_pid)
226 			continue;
227 
228 		sprintf(name, "/proc/%d/task", pid);
229 		items = scandir(name, &namelist, filter, NULL);
230 		if (items <= 0)
231 			goto out_free_threads;
232 
233 		total_tasks += items;
234 		nt = thread_map__realloc(threads, total_tasks);
235 		if (nt == NULL)
236 			goto out_free_namelist;
237 
238 		threads = nt;
239 
240 		for (i = 0; i < items; i++) {
241 			thread_map__set_pid(threads, j++, atoi(namelist[i]->d_name));
242 			zfree(&namelist[i]);
243 		}
244 		threads->nr = total_tasks;
245 		free(namelist);
246 	}
247 
248 out:
249 	strlist__delete(slist);
250 	if (threads)
251 		refcount_set(&threads->refcnt, 1);
252 	return threads;
253 
254 out_free_namelist:
255 	for (i = 0; i < items; i++)
256 		zfree(&namelist[i]);
257 	free(namelist);
258 
259 out_free_threads:
260 	zfree(&threads);
261 	goto out;
262 }
263 
264 struct thread_map *thread_map__new_dummy(void)
265 {
266 	struct thread_map *threads = thread_map__alloc(1);
267 
268 	if (threads != NULL) {
269 		thread_map__set_pid(threads, 0, -1);
270 		threads->nr = 1;
271 		refcount_set(&threads->refcnt, 1);
272 	}
273 	return threads;
274 }
275 
276 struct thread_map *thread_map__new_by_tid_str(const char *tid_str)
277 {
278 	struct thread_map *threads = NULL, *nt;
279 	int ntasks = 0;
280 	pid_t tid, prev_tid = INT_MAX;
281 	char *end_ptr;
282 	struct str_node *pos;
283 	struct strlist_config slist_config = { .dont_dupstr = true, };
284 	struct strlist *slist;
285 
286 	/* perf-stat expects threads to be generated even if tid not given */
287 	if (!tid_str)
288 		return thread_map__new_dummy();
289 
290 	slist = strlist__new(tid_str, &slist_config);
291 	if (!slist)
292 		return NULL;
293 
294 	strlist__for_each_entry(pos, slist) {
295 		tid = strtol(pos->s, &end_ptr, 10);
296 
297 		if (tid == INT_MIN || tid == INT_MAX ||
298 		    (*end_ptr != '\0' && *end_ptr != ','))
299 			goto out_free_threads;
300 
301 		if (tid == prev_tid)
302 			continue;
303 
304 		ntasks++;
305 		nt = thread_map__realloc(threads, ntasks);
306 
307 		if (nt == NULL)
308 			goto out_free_threads;
309 
310 		threads = nt;
311 		thread_map__set_pid(threads, ntasks - 1, tid);
312 		threads->nr = ntasks;
313 	}
314 out:
315 	if (threads)
316 		refcount_set(&threads->refcnt, 1);
317 	return threads;
318 
319 out_free_threads:
320 	zfree(&threads);
321 	strlist__delete(slist);
322 	goto out;
323 }
324 
325 struct thread_map *thread_map__new_str(const char *pid, const char *tid,
326 				       uid_t uid)
327 {
328 	if (pid)
329 		return thread_map__new_by_pid_str(pid);
330 
331 	if (!tid && uid != UINT_MAX)
332 		return thread_map__new_by_uid(uid);
333 
334 	return thread_map__new_by_tid_str(tid);
335 }
336 
337 static void thread_map__delete(struct thread_map *threads)
338 {
339 	if (threads) {
340 		int i;
341 
342 		WARN_ONCE(refcount_read(&threads->refcnt) != 0,
343 			  "thread map refcnt unbalanced\n");
344 		for (i = 0; i < threads->nr; i++)
345 			free(thread_map__comm(threads, i));
346 		free(threads);
347 	}
348 }
349 
350 struct thread_map *thread_map__get(struct thread_map *map)
351 {
352 	if (map)
353 		refcount_inc(&map->refcnt);
354 	return map;
355 }
356 
357 void thread_map__put(struct thread_map *map)
358 {
359 	if (map && refcount_dec_and_test(&map->refcnt))
360 		thread_map__delete(map);
361 }
362 
363 size_t thread_map__fprintf(struct thread_map *threads, FILE *fp)
364 {
365 	int i;
366 	size_t printed = fprintf(fp, "%d thread%s: ",
367 				 threads->nr, threads->nr > 1 ? "s" : "");
368 	for (i = 0; i < threads->nr; ++i)
369 		printed += fprintf(fp, "%s%d", i ? ", " : "", thread_map__pid(threads, i));
370 
371 	return printed + fprintf(fp, "\n");
372 }
373 
374 static int get_comm(char **comm, pid_t pid)
375 {
376 	char *path;
377 	size_t size;
378 	int err;
379 
380 	if (asprintf(&path, "%s/%d/comm", procfs__mountpoint(), pid) == -1)
381 		return -ENOMEM;
382 
383 	err = filename__read_str(path, comm, &size);
384 	if (!err) {
385 		/*
386 		 * We're reading 16 bytes, while filename__read_str
387 		 * allocates data per BUFSIZ bytes, so we can safely
388 		 * mark the end of the string.
389 		 */
390 		(*comm)[size] = 0;
391 		rtrim(*comm);
392 	}
393 
394 	free(path);
395 	return err;
396 }
397 
398 static void comm_init(struct thread_map *map, int i)
399 {
400 	pid_t pid = thread_map__pid(map, i);
401 	char *comm = NULL;
402 
403 	/* dummy pid comm initialization */
404 	if (pid == -1) {
405 		map->map[i].comm = strdup("dummy");
406 		return;
407 	}
408 
409 	/*
410 	 * The comm name is like extra bonus ;-),
411 	 * so just warn if we fail for any reason.
412 	 */
413 	if (get_comm(&comm, pid))
414 		pr_warning("Couldn't resolve comm name for pid %d\n", pid);
415 
416 	map->map[i].comm = comm;
417 }
418 
419 void thread_map__read_comms(struct thread_map *threads)
420 {
421 	int i;
422 
423 	for (i = 0; i < threads->nr; ++i)
424 		comm_init(threads, i);
425 }
426 
427 static void thread_map__copy_event(struct thread_map *threads,
428 				   struct thread_map_event *event)
429 {
430 	unsigned i;
431 
432 	threads->nr = (int) event->nr;
433 
434 	for (i = 0; i < event->nr; i++) {
435 		thread_map__set_pid(threads, i, (pid_t) event->entries[i].pid);
436 		threads->map[i].comm = strndup(event->entries[i].comm, 16);
437 	}
438 
439 	refcount_set(&threads->refcnt, 1);
440 }
441 
442 struct thread_map *thread_map__new_event(struct thread_map_event *event)
443 {
444 	struct thread_map *threads;
445 
446 	threads = thread_map__alloc(event->nr);
447 	if (threads)
448 		thread_map__copy_event(threads, event);
449 
450 	return threads;
451 }
452 
453 bool thread_map__has(struct thread_map *threads, pid_t pid)
454 {
455 	int i;
456 
457 	for (i = 0; i < threads->nr; ++i) {
458 		if (threads->map[i].pid == pid)
459 			return true;
460 	}
461 
462 	return false;
463 }
464 
465 int thread_map__remove(struct thread_map *threads, int idx)
466 {
467 	int i;
468 
469 	if (threads->nr < 1)
470 		return -EINVAL;
471 
472 	if (idx >= threads->nr)
473 		return -EINVAL;
474 
475 	/*
476 	 * Free the 'idx' item and shift the rest up.
477 	 */
478 	free(threads->map[idx].comm);
479 
480 	for (i = idx; i < threads->nr - 1; i++)
481 		threads->map[i] = threads->map[i + 1];
482 
483 	threads->nr--;
484 	return 0;
485 }
486