xref: /openbmc/linux/tools/perf/util/thread_map.c (revision a067558e) 
1 #include <dirent.h>
2 #include <limits.h>
3 #include <stdbool.h>
4 #include <stdlib.h>
5 #include <stdio.h>
6 #include <sys/types.h>
7 #include <sys/stat.h>
8 #include <unistd.h>
9 #include "string2.h"
10 #include "strlist.h"
11 #include <string.h>
12 #include <api/fs/fs.h>
13 #include "asm/bug.h"
14 #include "thread_map.h"
15 #include "util.h"
16 #include "debug.h"
17 #include "event.h"
18 
19 /* Skip "." and ".." directories */
20 static int filter(const struct dirent *dir)
21 {
22 	if (dir->d_name[0] == '.')
23 		return 0;
24 	else
25 		return 1;
26 }
27 
28 static void thread_map__reset(struct thread_map *map, int start, int nr)
29 {
30 	size_t size = (nr - start) * sizeof(map->map[0]);
31 
32 	memset(&map->map[start], 0, size);
33 }
34 
35 static struct thread_map *thread_map__realloc(struct thread_map *map, int nr)
36 {
37 	size_t size = sizeof(*map) + sizeof(map->map[0]) * nr;
38 	int start = map ? map->nr : 0;
39 
40 	map = realloc(map, size);
41 	/*
42 	 * We only realloc to add more items, let's reset new items.
43 	 */
44 	if (map)
45 		thread_map__reset(map, start, nr);
46 
47 	return map;
48 }
49 
50 #define thread_map__alloc(__nr) thread_map__realloc(NULL, __nr)
51 
52 struct thread_map *thread_map__new_by_pid(pid_t pid)
53 {
54 	struct thread_map *threads;
55 	char name[256];
56 	int items;
57 	struct dirent **namelist = NULL;
58 	int i;
59 
60 	sprintf(name, "/proc/%d/task", pid);
61 	items = scandir(name, &namelist, filter, NULL);
62 	if (items <= 0)
63 		return NULL;
64 
65 	threads = thread_map__alloc(items);
66 	if (threads != NULL) {
67 		for (i = 0; i < items; i++)
68 			thread_map__set_pid(threads, i, atoi(namelist[i]->d_name));
69 		threads->nr = items;
70 		refcount_set(&threads->refcnt, 1);
71 	}
72 
73 	for (i=0; i<items; i++)
74 		zfree(&namelist[i]);
75 	free(namelist);
76 
77 	return threads;
78 }
79 
80 struct thread_map *thread_map__new_by_tid(pid_t tid)
81 {
82 	struct thread_map *threads = thread_map__alloc(1);
83 
84 	if (threads != NULL) {
85 		thread_map__set_pid(threads, 0, tid);
86 		threads->nr = 1;
87 		refcount_set(&threads->refcnt, 1);
88 	}
89 
90 	return threads;
91 }
92 
93 struct thread_map *thread_map__new_by_uid(uid_t uid)
94 {
95 	DIR *proc;
96 	int max_threads = 32, items, i;
97 	char path[NAME_MAX + 1 + 6];
98 	struct dirent *dirent, **namelist = NULL;
99 	struct thread_map *threads = thread_map__alloc(max_threads);
100 
101 	if (threads == NULL)
102 		goto out;
103 
104 	proc = opendir("/proc");
105 	if (proc == NULL)
106 		goto out_free_threads;
107 
108 	threads->nr = 0;
109 	refcount_set(&threads->refcnt, 1);
110 
111 	while ((dirent = readdir(proc)) != NULL) {
112 		char *end;
113 		bool grow = false;
114 		struct stat st;
115 		pid_t pid = strtol(dirent->d_name, &end, 10);
116 
117 		if (*end) /* only interested in proper numerical dirents */
118 			continue;
119 
120 		snprintf(path, sizeof(path), "/proc/%s", dirent->d_name);
121 
122 		if (stat(path, &st) != 0)
123 			continue;
124 
125 		if (st.st_uid != uid)
126 			continue;
127 
128 		snprintf(path, sizeof(path), "/proc/%d/task", pid);
129 		items = scandir(path, &namelist, filter, NULL);
130 		if (items <= 0)
131 			goto out_free_closedir;
132 
133 		while (threads->nr + items >= max_threads) {
134 			max_threads *= 2;
135 			grow = true;
136 		}
137 
138 		if (grow) {
139 			struct thread_map *tmp;
140 
141 			tmp = thread_map__realloc(threads, max_threads);
142 			if (tmp == NULL)
143 				goto out_free_namelist;
144 
145 			threads = tmp;
146 		}
147 
148 		for (i = 0; i < items; i++) {
149 			thread_map__set_pid(threads, threads->nr + i,
150 					    atoi(namelist[i]->d_name));
151 		}
152 
153 		for (i = 0; i < items; i++)
154 			zfree(&namelist[i]);
155 		free(namelist);
156 
157 		threads->nr += items;
158 	}
159 
160 out_closedir:
161 	closedir(proc);
162 out:
163 	return threads;
164 
165 out_free_threads:
166 	free(threads);
167 	return NULL;
168 
169 out_free_namelist:
170 	for (i = 0; i < items; i++)
171 		zfree(&namelist[i]);
172 	free(namelist);
173 
174 out_free_closedir:
175 	zfree(&threads);
176 	goto out_closedir;
177 }
178 
179 struct thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid)
180 {
181 	if (pid != -1)
182 		return thread_map__new_by_pid(pid);
183 
184 	if (tid == -1 && uid != UINT_MAX)
185 		return thread_map__new_by_uid(uid);
186 
187 	return thread_map__new_by_tid(tid);
188 }
189 
190 static struct thread_map *thread_map__new_by_pid_str(const char *pid_str)
191 {
192 	struct thread_map *threads = NULL, *nt;
193 	char name[256];
194 	int items, total_tasks = 0;
195 	struct dirent **namelist = NULL;
196 	int i, j = 0;
197 	pid_t pid, prev_pid = INT_MAX;
198 	char *end_ptr;
199 	struct str_node *pos;
200 	struct strlist_config slist_config = { .dont_dupstr = true, };
201 	struct strlist *slist = strlist__new(pid_str, &slist_config);
202 
203 	if (!slist)
204 		return NULL;
205 
206 	strlist__for_each_entry(pos, slist) {
207 		pid = strtol(pos->s, &end_ptr, 10);
208 
209 		if (pid == INT_MIN || pid == INT_MAX ||
210 		    (*end_ptr != '\0' && *end_ptr != ','))
211 			goto out_free_threads;
212 
213 		if (pid == prev_pid)
214 			continue;
215 
216 		sprintf(name, "/proc/%d/task", pid);
217 		items = scandir(name, &namelist, filter, NULL);
218 		if (items <= 0)
219 			goto out_free_threads;
220 
221 		total_tasks += items;
222 		nt = thread_map__realloc(threads, total_tasks);
223 		if (nt == NULL)
224 			goto out_free_namelist;
225 
226 		threads = nt;
227 
228 		for (i = 0; i < items; i++) {
229 			thread_map__set_pid(threads, j++, atoi(namelist[i]->d_name));
230 			zfree(&namelist[i]);
231 		}
232 		threads->nr = total_tasks;
233 		free(namelist);
234 	}
235 
236 out:
237 	strlist__delete(slist);
238 	if (threads)
239 		refcount_set(&threads->refcnt, 1);
240 	return threads;
241 
242 out_free_namelist:
243 	for (i = 0; i < items; i++)
244 		zfree(&namelist[i]);
245 	free(namelist);
246 
247 out_free_threads:
248 	zfree(&threads);
249 	goto out;
250 }
251 
252 struct thread_map *thread_map__new_dummy(void)
253 {
254 	struct thread_map *threads = thread_map__alloc(1);
255 
256 	if (threads != NULL) {
257 		thread_map__set_pid(threads, 0, -1);
258 		threads->nr = 1;
259 		refcount_set(&threads->refcnt, 1);
260 	}
261 	return threads;
262 }
263 
264 struct thread_map *thread_map__new_by_tid_str(const char *tid_str)
265 {
266 	struct thread_map *threads = NULL, *nt;
267 	int ntasks = 0;
268 	pid_t tid, prev_tid = INT_MAX;
269 	char *end_ptr;
270 	struct str_node *pos;
271 	struct strlist_config slist_config = { .dont_dupstr = true, };
272 	struct strlist *slist;
273 
274 	/* perf-stat expects threads to be generated even if tid not given */
275 	if (!tid_str)
276 		return thread_map__new_dummy();
277 
278 	slist = strlist__new(tid_str, &slist_config);
279 	if (!slist)
280 		return NULL;
281 
282 	strlist__for_each_entry(pos, slist) {
283 		tid = strtol(pos->s, &end_ptr, 10);
284 
285 		if (tid == INT_MIN || tid == INT_MAX ||
286 		    (*end_ptr != '\0' && *end_ptr != ','))
287 			goto out_free_threads;
288 
289 		if (tid == prev_tid)
290 			continue;
291 
292 		ntasks++;
293 		nt = thread_map__realloc(threads, ntasks);
294 
295 		if (nt == NULL)
296 			goto out_free_threads;
297 
298 		threads = nt;
299 		thread_map__set_pid(threads, ntasks - 1, tid);
300 		threads->nr = ntasks;
301 	}
302 out:
303 	if (threads)
304 		refcount_set(&threads->refcnt, 1);
305 	return threads;
306 
307 out_free_threads:
308 	zfree(&threads);
309 	strlist__delete(slist);
310 	goto out;
311 }
312 
313 struct thread_map *thread_map__new_str(const char *pid, const char *tid,
314 				       uid_t uid)
315 {
316 	if (pid)
317 		return thread_map__new_by_pid_str(pid);
318 
319 	if (!tid && uid != UINT_MAX)
320 		return thread_map__new_by_uid(uid);
321 
322 	return thread_map__new_by_tid_str(tid);
323 }
324 
325 static void thread_map__delete(struct thread_map *threads)
326 {
327 	if (threads) {
328 		int i;
329 
330 		WARN_ONCE(refcount_read(&threads->refcnt) != 0,
331 			  "thread map refcnt unbalanced\n");
332 		for (i = 0; i < threads->nr; i++)
333 			free(thread_map__comm(threads, i));
334 		free(threads);
335 	}
336 }
337 
338 struct thread_map *thread_map__get(struct thread_map *map)
339 {
340 	if (map)
341 		refcount_inc(&map->refcnt);
342 	return map;
343 }
344 
345 void thread_map__put(struct thread_map *map)
346 {
347 	if (map && refcount_dec_and_test(&map->refcnt))
348 		thread_map__delete(map);
349 }
350 
351 size_t thread_map__fprintf(struct thread_map *threads, FILE *fp)
352 {
353 	int i;
354 	size_t printed = fprintf(fp, "%d thread%s: ",
355 				 threads->nr, threads->nr > 1 ? "s" : "");
356 	for (i = 0; i < threads->nr; ++i)
357 		printed += fprintf(fp, "%s%d", i ? ", " : "", thread_map__pid(threads, i));
358 
359 	return printed + fprintf(fp, "\n");
360 }
361 
362 static int get_comm(char **comm, pid_t pid)
363 {
364 	char *path;
365 	size_t size;
366 	int err;
367 
368 	if (asprintf(&path, "%s/%d/comm", procfs__mountpoint(), pid) == -1)
369 		return -ENOMEM;
370 
371 	err = filename__read_str(path, comm, &size);
372 	if (!err) {
373 		/*
374 		 * We're reading 16 bytes, while filename__read_str
375 		 * allocates data per BUFSIZ bytes, so we can safely
376 		 * mark the end of the string.
377 		 */
378 		(*comm)[size] = 0;
379 		rtrim(*comm);
380 	}
381 
382 	free(path);
383 	return err;
384 }
385 
386 static void comm_init(struct thread_map *map, int i)
387 {
388 	pid_t pid = thread_map__pid(map, i);
389 	char *comm = NULL;
390 
391 	/* dummy pid comm initialization */
392 	if (pid == -1) {
393 		map->map[i].comm = strdup("dummy");
394 		return;
395 	}
396 
397 	/*
398 	 * The comm name is like extra bonus ;-),
399 	 * so just warn if we fail for any reason.
400 	 */
401 	if (get_comm(&comm, pid))
402 		pr_warning("Couldn't resolve comm name for pid %d\n", pid);
403 
404 	map->map[i].comm = comm;
405 }
406 
407 void thread_map__read_comms(struct thread_map *threads)
408 {
409 	int i;
410 
411 	for (i = 0; i < threads->nr; ++i)
412 		comm_init(threads, i);
413 }
414 
415 static void thread_map__copy_event(struct thread_map *threads,
416 				   struct thread_map_event *event)
417 {
418 	unsigned i;
419 
420 	threads->nr = (int) event->nr;
421 
422 	for (i = 0; i < event->nr; i++) {
423 		thread_map__set_pid(threads, i, (pid_t) event->entries[i].pid);
424 		threads->map[i].comm = strndup(event->entries[i].comm, 16);
425 	}
426 
427 	refcount_set(&threads->refcnt, 1);
428 }
429 
430 struct thread_map *thread_map__new_event(struct thread_map_event *event)
431 {
432 	struct thread_map *threads;
433 
434 	threads = thread_map__alloc(event->nr);
435 	if (threads)
436 		thread_map__copy_event(threads, event);
437 
438 	return threads;
439 }
440 
441 bool thread_map__has(struct thread_map *threads, pid_t pid)
442 {
443 	int i;
444 
445 	for (i = 0; i < threads->nr; ++i) {
446 		if (threads->map[i].pid == pid)
447 			return true;
448 	}
449 
450 	return false;
451 }
452 
453 int thread_map__remove(struct thread_map *threads, int idx)
454 {
455 	int i;
456 
457 	if (threads->nr < 1)
458 		return -EINVAL;
459 
460 	if (idx >= threads->nr)
461 		return -EINVAL;
462 
463 	/*
464 	 * Free the 'idx' item and shift the rest up.
465 	 */
466 	free(threads->map[idx].comm);
467 
468 	for (i = idx; i < threads->nr - 1; i++)
469 		threads->map[i] = threads->map[i + 1];
470 
471 	threads->nr--;
472 	return 0;
473 }
474