xref: /linux/tools/perf/util/thread_map.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
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 <linux/string.h>
16 #include <linux/zalloc.h>
17 #include "asm/bug.h"
18 #include "thread_map.h"
19 #include "debug.h"
20 #include "event.h"
21 #include <internal/threadmap.h>
22 
23 /* Skip "." and ".." directories */
24 static int filter(const struct dirent *dir)
25 {
26 	if (dir->d_name[0] == '.')
27 		return 0;
28 	else
29 		return 1;
30 }
31 
32 #define thread_map__alloc(__nr) perf_thread_map__realloc(NULL, __nr)
33 
34 struct perf_thread_map *thread_map__new_by_pid(pid_t pid)
35 {
36 	struct perf_thread_map *threads;
37 	char name[256];
38 	int items;
39 	struct dirent **namelist = NULL;
40 	int i;
41 
42 	sprintf(name, "/proc/%d/task", pid);
43 	items = scandir(name, &namelist, filter, NULL);
44 	if (items <= 0)
45 		return NULL;
46 
47 	threads = thread_map__alloc(items);
48 	if (threads != NULL) {
49 		for (i = 0; i < items; i++)
50 			perf_thread_map__set_pid(threads, i, atoi(namelist[i]->d_name));
51 		threads->nr = items;
52 		refcount_set(&threads->refcnt, 1);
53 	}
54 
55 	for (i=0; i<items; i++)
56 		zfree(&namelist[i]);
57 	free(namelist);
58 
59 	return threads;
60 }
61 
62 struct perf_thread_map *thread_map__new_by_tid(pid_t tid)
63 {
64 	struct perf_thread_map *threads = thread_map__alloc(1);
65 
66 	if (threads != NULL) {
67 		perf_thread_map__set_pid(threads, 0, tid);
68 		threads->nr = 1;
69 		refcount_set(&threads->refcnt, 1);
70 	}
71 
72 	return threads;
73 }
74 
75 static struct perf_thread_map *__thread_map__new_all_cpus(uid_t uid)
76 {
77 	DIR *proc;
78 	int max_threads = 32, items, i;
79 	char path[NAME_MAX + 1 + 6];
80 	struct dirent *dirent, **namelist = NULL;
81 	struct perf_thread_map *threads = thread_map__alloc(max_threads);
82 
83 	if (threads == NULL)
84 		goto out;
85 
86 	proc = opendir("/proc");
87 	if (proc == NULL)
88 		goto out_free_threads;
89 
90 	threads->nr = 0;
91 	refcount_set(&threads->refcnt, 1);
92 
93 	while ((dirent = readdir(proc)) != NULL) {
94 		char *end;
95 		bool grow = false;
96 		pid_t pid = strtol(dirent->d_name, &end, 10);
97 
98 		if (*end) /* only interested in proper numerical dirents */
99 			continue;
100 
101 		snprintf(path, sizeof(path), "/proc/%s", dirent->d_name);
102 
103 		if (uid != UINT_MAX) {
104 			struct stat st;
105 
106 			if (stat(path, &st) != 0 || st.st_uid != uid)
107 				continue;
108 		}
109 
110 		snprintf(path, sizeof(path), "/proc/%d/task", pid);
111 		items = scandir(path, &namelist, filter, NULL);
112 		if (items <= 0) {
113 			pr_debug("scandir for %d returned empty, skipping\n", pid);
114 			continue;
115 		}
116 		while (threads->nr + items >= max_threads) {
117 			max_threads *= 2;
118 			grow = true;
119 		}
120 
121 		if (grow) {
122 			struct perf_thread_map *tmp;
123 
124 			tmp = perf_thread_map__realloc(threads, max_threads);
125 			if (tmp == NULL)
126 				goto out_free_namelist;
127 
128 			threads = tmp;
129 		}
130 
131 		for (i = 0; i < items; i++) {
132 			perf_thread_map__set_pid(threads, threads->nr + i,
133 						    atoi(namelist[i]->d_name));
134 		}
135 
136 		for (i = 0; i < items; i++)
137 			zfree(&namelist[i]);
138 		free(namelist);
139 
140 		threads->nr += items;
141 	}
142 
143 out_closedir:
144 	closedir(proc);
145 out:
146 	return threads;
147 
148 out_free_threads:
149 	free(threads);
150 	return NULL;
151 
152 out_free_namelist:
153 	for (i = 0; i < items; i++)
154 		zfree(&namelist[i]);
155 	free(namelist);
156 	zfree(&threads);
157 	goto out_closedir;
158 }
159 
160 struct perf_thread_map *thread_map__new_all_cpus(void)
161 {
162 	return __thread_map__new_all_cpus(UINT_MAX);
163 }
164 
165 struct perf_thread_map *thread_map__new_by_uid(uid_t uid)
166 {
167 	return __thread_map__new_all_cpus(uid);
168 }
169 
170 struct perf_thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid)
171 {
172 	if (pid != -1)
173 		return thread_map__new_by_pid(pid);
174 
175 	if (tid == -1 && uid != UINT_MAX)
176 		return thread_map__new_by_uid(uid);
177 
178 	return thread_map__new_by_tid(tid);
179 }
180 
181 static struct perf_thread_map *thread_map__new_by_pid_str(const char *pid_str)
182 {
183 	struct perf_thread_map *threads = NULL, *nt;
184 	char name[256];
185 	int items, total_tasks = 0;
186 	struct dirent **namelist = NULL;
187 	int i, j = 0;
188 	pid_t pid, prev_pid = INT_MAX;
189 	char *end_ptr;
190 	struct str_node *pos;
191 	struct strlist_config slist_config = { .dont_dupstr = true, };
192 	struct strlist *slist = strlist__new(pid_str, &slist_config);
193 
194 	if (!slist)
195 		return NULL;
196 
197 	strlist__for_each_entry(pos, slist) {
198 		pid = strtol(pos->s, &end_ptr, 10);
199 
200 		if (pid == INT_MIN || pid == INT_MAX ||
201 		    (*end_ptr != '\0' && *end_ptr != ','))
202 			goto out_free_threads;
203 
204 		if (pid == prev_pid)
205 			continue;
206 
207 		sprintf(name, "/proc/%d/task", pid);
208 		items = scandir(name, &namelist, filter, NULL);
209 		if (items <= 0)
210 			goto out_free_threads;
211 
212 		total_tasks += items;
213 		nt = perf_thread_map__realloc(threads, total_tasks);
214 		if (nt == NULL)
215 			goto out_free_namelist;
216 
217 		threads = nt;
218 
219 		for (i = 0; i < items; i++) {
220 			perf_thread_map__set_pid(threads, j++, atoi(namelist[i]->d_name));
221 			zfree(&namelist[i]);
222 		}
223 		threads->nr = total_tasks;
224 		free(namelist);
225 	}
226 
227 out:
228 	strlist__delete(slist);
229 	if (threads)
230 		refcount_set(&threads->refcnt, 1);
231 	return threads;
232 
233 out_free_namelist:
234 	for (i = 0; i < items; i++)
235 		zfree(&namelist[i]);
236 	free(namelist);
237 
238 out_free_threads:
239 	zfree(&threads);
240 	goto out;
241 }
242 
243 struct perf_thread_map *thread_map__new_by_tid_str(const char *tid_str)
244 {
245 	struct perf_thread_map *threads = NULL, *nt;
246 	int ntasks = 0;
247 	pid_t tid, prev_tid = INT_MAX;
248 	char *end_ptr;
249 	struct str_node *pos;
250 	struct strlist_config slist_config = { .dont_dupstr = true, };
251 	struct strlist *slist;
252 
253 	/* perf-stat expects threads to be generated even if tid not given */
254 	if (!tid_str)
255 		return perf_thread_map__new_dummy();
256 
257 	slist = strlist__new(tid_str, &slist_config);
258 	if (!slist)
259 		return NULL;
260 
261 	strlist__for_each_entry(pos, slist) {
262 		tid = strtol(pos->s, &end_ptr, 10);
263 
264 		if (tid == INT_MIN || tid == INT_MAX ||
265 		    (*end_ptr != '\0' && *end_ptr != ','))
266 			goto out_free_threads;
267 
268 		if (tid == prev_tid)
269 			continue;
270 
271 		ntasks++;
272 		nt = perf_thread_map__realloc(threads, ntasks);
273 
274 		if (nt == NULL)
275 			goto out_free_threads;
276 
277 		threads = nt;
278 		perf_thread_map__set_pid(threads, ntasks - 1, tid);
279 		threads->nr = ntasks;
280 	}
281 out:
282 	strlist__delete(slist);
283 	if (threads)
284 		refcount_set(&threads->refcnt, 1);
285 	return threads;
286 
287 out_free_threads:
288 	zfree(&threads);
289 	goto out;
290 }
291 
292 struct perf_thread_map *thread_map__new_str(const char *pid, const char *tid,
293 				       uid_t uid, bool all_threads)
294 {
295 	if (pid)
296 		return thread_map__new_by_pid_str(pid);
297 
298 	if (!tid && uid != UINT_MAX)
299 		return thread_map__new_by_uid(uid);
300 
301 	if (all_threads)
302 		return thread_map__new_all_cpus();
303 
304 	return thread_map__new_by_tid_str(tid);
305 }
306 
307 size_t thread_map__fprintf(struct perf_thread_map *threads, FILE *fp)
308 {
309 	int i;
310 	size_t printed = fprintf(fp, "%d thread%s: ",
311 				 threads->nr, threads->nr > 1 ? "s" : "");
312 	for (i = 0; i < threads->nr; ++i)
313 		printed += fprintf(fp, "%s%d", i ? ", " : "", perf_thread_map__pid(threads, i));
314 
315 	return printed + fprintf(fp, "\n");
316 }
317 
318 static int get_comm(char **comm, pid_t pid)
319 {
320 	char *path;
321 	size_t size;
322 	int err;
323 
324 	if (asprintf(&path, "%s/%d/comm", procfs__mountpoint(), pid) == -1)
325 		return -ENOMEM;
326 
327 	err = filename__read_str(path, comm, &size);
328 	if (!err) {
329 		/*
330 		 * We're reading 16 bytes, while filename__read_str
331 		 * allocates data per BUFSIZ bytes, so we can safely
332 		 * mark the end of the string.
333 		 */
334 		(*comm)[size] = 0;
335 		strim(*comm);
336 	}
337 
338 	free(path);
339 	return err;
340 }
341 
342 static void comm_init(struct perf_thread_map *map, int i)
343 {
344 	pid_t pid = perf_thread_map__pid(map, i);
345 	char *comm = NULL;
346 
347 	/* dummy pid comm initialization */
348 	if (pid == -1) {
349 		map->map[i].comm = strdup("dummy");
350 		return;
351 	}
352 
353 	/*
354 	 * The comm name is like extra bonus ;-),
355 	 * so just warn if we fail for any reason.
356 	 */
357 	if (get_comm(&comm, pid))
358 		pr_warning("Couldn't resolve comm name for pid %d\n", pid);
359 
360 	map->map[i].comm = comm;
361 }
362 
363 void thread_map__read_comms(struct perf_thread_map *threads)
364 {
365 	int i;
366 
367 	for (i = 0; i < threads->nr; ++i)
368 		comm_init(threads, i);
369 }
370 
371 static void thread_map__copy_event(struct perf_thread_map *threads,
372 				   struct perf_record_thread_map *event)
373 {
374 	unsigned i;
375 
376 	threads->nr = (int) event->nr;
377 
378 	for (i = 0; i < event->nr; i++) {
379 		perf_thread_map__set_pid(threads, i, (pid_t) event->entries[i].pid);
380 		threads->map[i].comm = strndup(event->entries[i].comm, 16);
381 	}
382 
383 	refcount_set(&threads->refcnt, 1);
384 }
385 
386 struct perf_thread_map *thread_map__new_event(struct perf_record_thread_map *event)
387 {
388 	struct perf_thread_map *threads;
389 
390 	threads = thread_map__alloc(event->nr);
391 	if (threads)
392 		thread_map__copy_event(threads, event);
393 
394 	return threads;
395 }
396 
397 bool thread_map__has(struct perf_thread_map *threads, pid_t pid)
398 {
399 	int i;
400 
401 	for (i = 0; i < threads->nr; ++i) {
402 		if (threads->map[i].pid == pid)
403 			return true;
404 	}
405 
406 	return false;
407 }
408 
409 int thread_map__remove(struct perf_thread_map *threads, int idx)
410 {
411 	int i;
412 
413 	if (threads->nr < 1)
414 		return -EINVAL;
415 
416 	if (idx >= threads->nr)
417 		return -EINVAL;
418 
419 	/*
420 	 * Free the 'idx' item and shift the rest up.
421 	 */
422 	zfree(&threads->map[idx].comm);
423 
424 	for (i = idx; i < threads->nr - 1; i++)
425 		threads->map[i] = threads->map[i + 1];
426 
427 	threads->nr--;
428 	return 0;
429 }
430