xref: /linux/tools/perf/util/thread_map.c (revision bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43) 
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(void)
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/%d/task", pid);
102 		items = scandir(path, &namelist, filter, NULL);
103 		if (items <= 0) {
104 			pr_debug("scandir for %d returned empty, skipping\n", pid);
105 			continue;
106 		}
107 		while (threads->nr + items >= max_threads) {
108 			max_threads *= 2;
109 			grow = true;
110 		}
111 
112 		if (grow) {
113 			struct perf_thread_map *tmp;
114 
115 			tmp = perf_thread_map__realloc(threads, max_threads);
116 			if (tmp == NULL)
117 				goto out_free_namelist;
118 
119 			threads = tmp;
120 		}
121 
122 		for (i = 0; i < items; i++) {
123 			perf_thread_map__set_pid(threads, threads->nr + i,
124 						    atoi(namelist[i]->d_name));
125 		}
126 
127 		for (i = 0; i < items; i++)
128 			zfree(&namelist[i]);
129 		free(namelist);
130 
131 		threads->nr += items;
132 	}
133 
134 out_closedir:
135 	closedir(proc);
136 out:
137 	return threads;
138 
139 out_free_threads:
140 	free(threads);
141 	return NULL;
142 
143 out_free_namelist:
144 	for (i = 0; i < items; i++)
145 		zfree(&namelist[i]);
146 	free(namelist);
147 	zfree(&threads);
148 	goto out_closedir;
149 }
150 
151 struct perf_thread_map *thread_map__new(pid_t pid, pid_t tid)
152 {
153 	if (pid != -1)
154 		return thread_map__new_by_pid(pid);
155 
156 	return thread_map__new_by_tid(tid);
157 }
158 
159 static struct perf_thread_map *thread_map__new_by_pid_str(const char *pid_str)
160 {
161 	struct perf_thread_map *threads = NULL, *nt;
162 	char name[256];
163 	int items, total_tasks = 0;
164 	struct dirent **namelist = NULL;
165 	int i, j = 0;
166 	pid_t pid, prev_pid = INT_MAX;
167 	struct str_node *pos;
168 	struct strlist *slist = strlist__new(pid_str, NULL);
169 
170 	if (!slist)
171 		return NULL;
172 
173 	strlist__for_each_entry(pos, slist) {
174 		pid = strtol(pos->s, NULL, 10);
175 
176 		if (pid == INT_MIN || pid == INT_MAX)
177 			goto out_free_threads;
178 
179 		if (pid == prev_pid)
180 			continue;
181 
182 		sprintf(name, "/proc/%d/task", pid);
183 		items = scandir(name, &namelist, filter, NULL);
184 		if (items <= 0)
185 			goto out_free_threads;
186 
187 		total_tasks += items;
188 		nt = perf_thread_map__realloc(threads, total_tasks);
189 		if (nt == NULL)
190 			goto out_free_namelist;
191 
192 		threads = nt;
193 
194 		for (i = 0; i < items; i++) {
195 			perf_thread_map__set_pid(threads, j++, atoi(namelist[i]->d_name));
196 			zfree(&namelist[i]);
197 		}
198 		threads->nr = total_tasks;
199 		free(namelist);
200 	}
201 
202 out:
203 	strlist__delete(slist);
204 	if (threads)
205 		refcount_set(&threads->refcnt, 1);
206 	return threads;
207 
208 out_free_namelist:
209 	for (i = 0; i < items; i++)
210 		zfree(&namelist[i]);
211 	free(namelist);
212 
213 out_free_threads:
214 	zfree(&threads);
215 	goto out;
216 }
217 
218 struct perf_thread_map *thread_map__new_by_tid_str(const char *tid_str)
219 {
220 	struct perf_thread_map *threads = NULL, *nt;
221 	int ntasks = 0;
222 	pid_t tid, prev_tid = INT_MAX;
223 	struct str_node *pos;
224 	struct strlist *slist;
225 
226 	/* perf-stat expects threads to be generated even if tid not given */
227 	if (!tid_str)
228 		return perf_thread_map__new_dummy();
229 
230 	slist = strlist__new(tid_str, NULL);
231 	if (!slist)
232 		return NULL;
233 
234 	strlist__for_each_entry(pos, slist) {
235 		tid = strtol(pos->s, NULL, 10);
236 
237 		if (tid == INT_MIN || tid == INT_MAX)
238 			goto out_free_threads;
239 
240 		if (tid == prev_tid)
241 			continue;
242 
243 		ntasks++;
244 		nt = perf_thread_map__realloc(threads, ntasks);
245 
246 		if (nt == NULL)
247 			goto out_free_threads;
248 
249 		threads = nt;
250 		perf_thread_map__set_pid(threads, ntasks - 1, tid);
251 		threads->nr = ntasks;
252 	}
253 out:
254 	strlist__delete(slist);
255 	if (threads)
256 		refcount_set(&threads->refcnt, 1);
257 	return threads;
258 
259 out_free_threads:
260 	zfree(&threads);
261 	goto out;
262 }
263 
264 struct perf_thread_map *thread_map__new_str(const char *pid, const char *tid, bool all_threads)
265 {
266 	if (pid)
267 		return thread_map__new_by_pid_str(pid);
268 
269 	if (all_threads)
270 		return thread_map__new_all_cpus();
271 
272 	return thread_map__new_by_tid_str(tid);
273 }
274 
275 size_t thread_map__fprintf(struct perf_thread_map *threads, FILE *fp)
276 {
277 	int i;
278 	size_t printed = fprintf(fp, "%d thread%s: ",
279 				 threads->nr, threads->nr > 1 ? "s" : "");
280 	for (i = 0; i < threads->nr; ++i)
281 		printed += fprintf(fp, "%s%d", i ? ", " : "", perf_thread_map__pid(threads, i));
282 
283 	return printed + fprintf(fp, "\n");
284 }
285 
286 static int get_comm(char **comm, pid_t pid)
287 {
288 	char *path;
289 	size_t size;
290 	int err;
291 
292 	if (asprintf(&path, "%s/%d/comm", procfs__mountpoint(), pid) == -1)
293 		return -ENOMEM;
294 
295 	err = filename__read_str(path, comm, &size);
296 	if (!err) {
297 		/*
298 		 * We're reading 16 bytes, while filename__read_str
299 		 * allocates data per BUFSIZ bytes, so we can safely
300 		 * mark the end of the string.
301 		 */
302 		(*comm)[size] = 0;
303 		strim(*comm);
304 	}
305 
306 	free(path);
307 	return err;
308 }
309 
310 static void comm_init(struct perf_thread_map *map, int i)
311 {
312 	pid_t pid = perf_thread_map__pid(map, i);
313 	char *comm = NULL;
314 
315 	/* dummy pid comm initialization */
316 	if (pid == -1) {
317 		map->map[i].comm = strdup("dummy");
318 		return;
319 	}
320 
321 	/*
322 	 * The comm name is like extra bonus ;-),
323 	 * so just warn if we fail for any reason.
324 	 */
325 	if (get_comm(&comm, pid))
326 		pr_warning("Couldn't resolve comm name for pid %d\n", pid);
327 
328 	map->map[i].comm = comm;
329 }
330 
331 void thread_map__read_comms(struct perf_thread_map *threads)
332 {
333 	int i;
334 
335 	for (i = 0; i < threads->nr; ++i)
336 		comm_init(threads, i);
337 }
338 
339 static void thread_map__copy_event(struct perf_thread_map *threads,
340 				   struct perf_record_thread_map *event)
341 {
342 	unsigned i;
343 
344 	threads->nr = (int) event->nr;
345 
346 	for (i = 0; i < event->nr; i++) {
347 		perf_thread_map__set_pid(threads, i, (pid_t) event->entries[i].pid);
348 		threads->map[i].comm = strndup(event->entries[i].comm, 16);
349 	}
350 
351 	refcount_set(&threads->refcnt, 1);
352 }
353 
354 struct perf_thread_map *thread_map__new_event(struct perf_record_thread_map *event)
355 {
356 	struct perf_thread_map *threads;
357 
358 	threads = thread_map__alloc(event->nr);
359 	if (threads)
360 		thread_map__copy_event(threads, event);
361 
362 	return threads;
363 }
364 
365 bool thread_map__has(struct perf_thread_map *threads, pid_t pid)
366 {
367 	int i;
368 
369 	for (i = 0; i < threads->nr; ++i) {
370 		if (threads->map[i].pid == pid)
371 			return true;
372 	}
373 
374 	return false;
375 }
376 
377 int thread_map__remove(struct perf_thread_map *threads, int idx)
378 {
379 	int i;
380 
381 	if (threads->nr < 1)
382 		return -EINVAL;
383 
384 	if (idx >= threads->nr)
385 		return -EINVAL;
386 
387 	/*
388 	 * Free the 'idx' item and shift the rest up.
389 	 */
390 	zfree(&threads->map[idx].comm);
391 
392 	for (i = idx; i < threads->nr - 1; i++)
393 		threads->map[i] = threads->map[i + 1];
394 
395 	threads->nr--;
396 	return 0;
397 }
398