xref: /linux/tools/perf/util/thread_map.c (revision f3a8b6645dc2e60d11f20c1c23afd964ff4e55ae) 
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 "strlist.h"
10 #include <string.h>
11 #include <api/fs/fs.h>
12 #include "asm/bug.h"
13 #include "thread_map.h"
14 #include "util.h"
15 #include "debug.h"
16 #include "event.h"
17 
18 /* Skip "." and ".." directories */
19 static int filter(const struct dirent *dir)
20 {
21 	if (dir->d_name[0] == '.')
22 		return 0;
23 	else
24 		return 1;
25 }
26 
27 static void thread_map__reset(struct thread_map *map, int start, int nr)
28 {
29 	size_t size = (nr - start) * sizeof(map->map[0]);
30 
31 	memset(&map->map[start], 0, size);
32 }
33 
34 static struct thread_map *thread_map__realloc(struct thread_map *map, int nr)
35 {
36 	size_t size = sizeof(*map) + sizeof(map->map[0]) * nr;
37 	int start = map ? map->nr : 0;
38 
39 	map = realloc(map, size);
40 	/*
41 	 * We only realloc to add more items, let's reset new items.
42 	 */
43 	if (map)
44 		thread_map__reset(map, start, nr);
45 
46 	return map;
47 }
48 
49 #define thread_map__alloc(__nr) thread_map__realloc(NULL, __nr)
50 
51 struct thread_map *thread_map__new_by_pid(pid_t pid)
52 {
53 	struct thread_map *threads;
54 	char name[256];
55 	int items;
56 	struct dirent **namelist = NULL;
57 	int i;
58 
59 	sprintf(name, "/proc/%d/task", pid);
60 	items = scandir(name, &namelist, filter, NULL);
61 	if (items <= 0)
62 		return NULL;
63 
64 	threads = thread_map__alloc(items);
65 	if (threads != NULL) {
66 		for (i = 0; i < items; i++)
67 			thread_map__set_pid(threads, i, atoi(namelist[i]->d_name));
68 		threads->nr = items;
69 		atomic_set(&threads->refcnt, 1);
70 	}
71 
72 	for (i=0; i<items; i++)
73 		zfree(&namelist[i]);
74 	free(namelist);
75 
76 	return threads;
77 }
78 
79 struct thread_map *thread_map__new_by_tid(pid_t tid)
80 {
81 	struct thread_map *threads = thread_map__alloc(1);
82 
83 	if (threads != NULL) {
84 		thread_map__set_pid(threads, 0, tid);
85 		threads->nr = 1;
86 		atomic_set(&threads->refcnt, 1);
87 	}
88 
89 	return threads;
90 }
91 
92 struct thread_map *thread_map__new_by_uid(uid_t uid)
93 {
94 	DIR *proc;
95 	int max_threads = 32, items, i;
96 	char path[256];
97 	struct dirent *dirent, **namelist = NULL;
98 	struct thread_map *threads = thread_map__alloc(max_threads);
99 
100 	if (threads == NULL)
101 		goto out;
102 
103 	proc = opendir("/proc");
104 	if (proc == NULL)
105 		goto out_free_threads;
106 
107 	threads->nr = 0;
108 	atomic_set(&threads->refcnt, 1);
109 
110 	while ((dirent = readdir(proc)) != NULL) {
111 		char *end;
112 		bool grow = false;
113 		struct stat st;
114 		pid_t pid = strtol(dirent->d_name, &end, 10);
115 
116 		if (*end) /* only interested in proper numerical dirents */
117 			continue;
118 
119 		snprintf(path, sizeof(path), "/proc/%s", dirent->d_name);
120 
121 		if (stat(path, &st) != 0)
122 			continue;
123 
124 		if (st.st_uid != uid)
125 			continue;
126 
127 		snprintf(path, sizeof(path), "/proc/%d/task", pid);
128 		items = scandir(path, &namelist, filter, NULL);
129 		if (items <= 0)
130 			goto out_free_closedir;
131 
132 		while (threads->nr + items >= max_threads) {
133 			max_threads *= 2;
134 			grow = true;
135 		}
136 
137 		if (grow) {
138 			struct thread_map *tmp;
139 
140 			tmp = thread_map__realloc(threads, max_threads);
141 			if (tmp == NULL)
142 				goto out_free_namelist;
143 
144 			threads = tmp;
145 		}
146 
147 		for (i = 0; i < items; i++) {
148 			thread_map__set_pid(threads, threads->nr + i,
149 					    atoi(namelist[i]->d_name));
150 		}
151 
152 		for (i = 0; i < items; i++)
153 			zfree(&namelist[i]);
154 		free(namelist);
155 
156 		threads->nr += items;
157 	}
158 
159 out_closedir:
160 	closedir(proc);
161 out:
162 	return threads;
163 
164 out_free_threads:
165 	free(threads);
166 	return NULL;
167 
168 out_free_namelist:
169 	for (i = 0; i < items; i++)
170 		zfree(&namelist[i]);
171 	free(namelist);
172 
173 out_free_closedir:
174 	zfree(&threads);
175 	goto out_closedir;
176 }
177 
178 struct thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid)
179 {
180 	if (pid != -1)
181 		return thread_map__new_by_pid(pid);
182 
183 	if (tid == -1 && uid != UINT_MAX)
184 		return thread_map__new_by_uid(uid);
185 
186 	return thread_map__new_by_tid(tid);
187 }
188 
189 static struct thread_map *thread_map__new_by_pid_str(const char *pid_str)
190 {
191 	struct thread_map *threads = NULL, *nt;
192 	char name[256];
193 	int items, total_tasks = 0;
194 	struct dirent **namelist = NULL;
195 	int i, j = 0;
196 	pid_t pid, prev_pid = INT_MAX;
197 	char *end_ptr;
198 	struct str_node *pos;
199 	struct strlist_config slist_config = { .dont_dupstr = true, };
200 	struct strlist *slist = strlist__new(pid_str, &slist_config);
201 
202 	if (!slist)
203 		return NULL;
204 
205 	strlist__for_each_entry(pos, slist) {
206 		pid = strtol(pos->s, &end_ptr, 10);
207 
208 		if (pid == INT_MIN || pid == INT_MAX ||
209 		    (*end_ptr != '\0' && *end_ptr != ','))
210 			goto out_free_threads;
211 
212 		if (pid == prev_pid)
213 			continue;
214 
215 		sprintf(name, "/proc/%d/task", pid);
216 		items = scandir(name, &namelist, filter, NULL);
217 		if (items <= 0)
218 			goto out_free_threads;
219 
220 		total_tasks += items;
221 		nt = thread_map__realloc(threads, total_tasks);
222 		if (nt == NULL)
223 			goto out_free_namelist;
224 
225 		threads = nt;
226 
227 		for (i = 0; i < items; i++) {
228 			thread_map__set_pid(threads, j++, atoi(namelist[i]->d_name));
229 			zfree(&namelist[i]);
230 		}
231 		threads->nr = total_tasks;
232 		free(namelist);
233 	}
234 
235 out:
236 	strlist__delete(slist);
237 	if (threads)
238 		atomic_set(&threads->refcnt, 1);
239 	return threads;
240 
241 out_free_namelist:
242 	for (i = 0; i < items; i++)
243 		zfree(&namelist[i]);
244 	free(namelist);
245 
246 out_free_threads:
247 	zfree(&threads);
248 	goto out;
249 }
250 
251 struct thread_map *thread_map__new_dummy(void)
252 {
253 	struct thread_map *threads = thread_map__alloc(1);
254 
255 	if (threads != NULL) {
256 		thread_map__set_pid(threads, 0, -1);
257 		threads->nr = 1;
258 		atomic_set(&threads->refcnt, 1);
259 	}
260 	return threads;
261 }
262 
263 struct thread_map *thread_map__new_by_tid_str(const char *tid_str)
264 {
265 	struct thread_map *threads = NULL, *nt;
266 	int ntasks = 0;
267 	pid_t tid, prev_tid = INT_MAX;
268 	char *end_ptr;
269 	struct str_node *pos;
270 	struct strlist_config slist_config = { .dont_dupstr = true, };
271 	struct strlist *slist;
272 
273 	/* perf-stat expects threads to be generated even if tid not given */
274 	if (!tid_str)
275 		return thread_map__new_dummy();
276 
277 	slist = strlist__new(tid_str, &slist_config);
278 	if (!slist)
279 		return NULL;
280 
281 	strlist__for_each_entry(pos, slist) {
282 		tid = strtol(pos->s, &end_ptr, 10);
283 
284 		if (tid == INT_MIN || tid == INT_MAX ||
285 		    (*end_ptr != '\0' && *end_ptr != ','))
286 			goto out_free_threads;
287 
288 		if (tid == prev_tid)
289 			continue;
290 
291 		ntasks++;
292 		nt = thread_map__realloc(threads, ntasks);
293 
294 		if (nt == NULL)
295 			goto out_free_threads;
296 
297 		threads = nt;
298 		thread_map__set_pid(threads, ntasks - 1, tid);
299 		threads->nr = ntasks;
300 	}
301 out:
302 	if (threads)
303 		atomic_set(&threads->refcnt, 1);
304 	return threads;
305 
306 out_free_threads:
307 	zfree(&threads);
308 	strlist__delete(slist);
309 	goto out;
310 }
311 
312 struct thread_map *thread_map__new_str(const char *pid, const char *tid,
313 				       uid_t uid)
314 {
315 	if (pid)
316 		return thread_map__new_by_pid_str(pid);
317 
318 	if (!tid && uid != UINT_MAX)
319 		return thread_map__new_by_uid(uid);
320 
321 	return thread_map__new_by_tid_str(tid);
322 }
323 
324 static void thread_map__delete(struct thread_map *threads)
325 {
326 	if (threads) {
327 		int i;
328 
329 		WARN_ONCE(atomic_read(&threads->refcnt) != 0,
330 			  "thread map refcnt unbalanced\n");
331 		for (i = 0; i < threads->nr; i++)
332 			free(thread_map__comm(threads, i));
333 		free(threads);
334 	}
335 }
336 
337 struct thread_map *thread_map__get(struct thread_map *map)
338 {
339 	if (map)
340 		atomic_inc(&map->refcnt);
341 	return map;
342 }
343 
344 void thread_map__put(struct thread_map *map)
345 {
346 	if (map && atomic_dec_and_test(&map->refcnt))
347 		thread_map__delete(map);
348 }
349 
350 size_t thread_map__fprintf(struct thread_map *threads, FILE *fp)
351 {
352 	int i;
353 	size_t printed = fprintf(fp, "%d thread%s: ",
354 				 threads->nr, threads->nr > 1 ? "s" : "");
355 	for (i = 0; i < threads->nr; ++i)
356 		printed += fprintf(fp, "%s%d", i ? ", " : "", thread_map__pid(threads, i));
357 
358 	return printed + fprintf(fp, "\n");
359 }
360 
361 static int get_comm(char **comm, pid_t pid)
362 {
363 	char *path;
364 	size_t size;
365 	int err;
366 
367 	if (asprintf(&path, "%s/%d/comm", procfs__mountpoint(), pid) == -1)
368 		return -ENOMEM;
369 
370 	err = filename__read_str(path, comm, &size);
371 	if (!err) {
372 		/*
373 		 * We're reading 16 bytes, while filename__read_str
374 		 * allocates data per BUFSIZ bytes, so we can safely
375 		 * mark the end of the string.
376 		 */
377 		(*comm)[size] = 0;
378 		rtrim(*comm);
379 	}
380 
381 	free(path);
382 	return err;
383 }
384 
385 static void comm_init(struct thread_map *map, int i)
386 {
387 	pid_t pid = thread_map__pid(map, i);
388 	char *comm = NULL;
389 
390 	/* dummy pid comm initialization */
391 	if (pid == -1) {
392 		map->map[i].comm = strdup("dummy");
393 		return;
394 	}
395 
396 	/*
397 	 * The comm name is like extra bonus ;-),
398 	 * so just warn if we fail for any reason.
399 	 */
400 	if (get_comm(&comm, pid))
401 		pr_warning("Couldn't resolve comm name for pid %d\n", pid);
402 
403 	map->map[i].comm = comm;
404 }
405 
406 void thread_map__read_comms(struct thread_map *threads)
407 {
408 	int i;
409 
410 	for (i = 0; i < threads->nr; ++i)
411 		comm_init(threads, i);
412 }
413 
414 static void thread_map__copy_event(struct thread_map *threads,
415 				   struct thread_map_event *event)
416 {
417 	unsigned i;
418 
419 	threads->nr = (int) event->nr;
420 
421 	for (i = 0; i < event->nr; i++) {
422 		thread_map__set_pid(threads, i, (pid_t) event->entries[i].pid);
423 		threads->map[i].comm = strndup(event->entries[i].comm, 16);
424 	}
425 
426 	atomic_set(&threads->refcnt, 1);
427 }
428 
429 struct thread_map *thread_map__new_event(struct thread_map_event *event)
430 {
431 	struct thread_map *threads;
432 
433 	threads = thread_map__alloc(event->nr);
434 	if (threads)
435 		thread_map__copy_event(threads, event);
436 
437 	return threads;
438 }
439 
440 bool thread_map__has(struct thread_map *threads, pid_t pid)
441 {
442 	int i;
443 
444 	for (i = 0; i < threads->nr; ++i) {
445 		if (threads->map[i].pid == pid)
446 			return true;
447 	}
448 
449 	return false;
450 }
451