1// SPDX-License-Identifier: GPL-2.0
2#include <subcmd/parse-options.h>
3#include "evsel.h"
4#include "cgroup.h"
5#include "evlist.h"
6#include "rblist.h"
7#include "metricgroup.h"
8#include "stat.h"
9#include <linux/zalloc.h>
10#include <sys/types.h>
11#include <sys/stat.h>
12#include <sys/statfs.h>
13#include <fcntl.h>
14#include <stdlib.h>
15#include <string.h>
16#include <api/fs/fs.h>
17#include <ftw.h>
18#include <regex.h>
19
20int nr_cgroups;
21bool cgrp_event_expanded;
22
23/* used to match cgroup name with patterns */
24struct cgroup_name {
25	struct list_head list;
26	bool used;
27	char name[];
28};
29static LIST_HEAD(cgroup_list);
30
31static int open_cgroup(const char *name)
32{
33	char path[PATH_MAX + 1];
34	char mnt[PATH_MAX + 1];
35	int fd;
36
37
38	if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event"))
39		return -1;
40
41	scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
42
43	fd = open(path, O_RDONLY);
44	if (fd == -1)
45		fprintf(stderr, "no access to cgroup %s\n", path);
46
47	return fd;
48}
49
50#ifdef HAVE_FILE_HANDLE
51static u64 __read_cgroup_id(const char *path)
52{
53	struct {
54		struct file_handle fh;
55		uint64_t cgroup_id;
56	} handle;
57	int mount_id;
58
59	handle.fh.handle_bytes = sizeof(handle.cgroup_id);
60	if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0)
61		return -1ULL;
62
63	return handle.cgroup_id;
64}
65
66int read_cgroup_id(struct cgroup *cgrp)
67{
68	char path[PATH_MAX + 1];
69	char mnt[PATH_MAX + 1];
70
71	if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event"))
72		return -1;
73
74	scnprintf(path, PATH_MAX, "%s/%s", mnt, cgrp->name);
75
76	cgrp->id = __read_cgroup_id(path);
77	return 0;
78}
79#else
80static inline u64 __read_cgroup_id(const char *path __maybe_unused) { return -1ULL; }
81#endif  /* HAVE_FILE_HANDLE */
82
83#ifndef CGROUP2_SUPER_MAGIC
84#define CGROUP2_SUPER_MAGIC  0x63677270
85#endif
86
87int cgroup_is_v2(const char *subsys)
88{
89	char mnt[PATH_MAX + 1];
90	struct statfs stbuf;
91
92	if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, subsys))
93		return -1;
94
95	if (statfs(mnt, &stbuf) < 0)
96		return -1;
97
98	return (stbuf.f_type == CGROUP2_SUPER_MAGIC);
99}
100
101static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str)
102{
103	struct evsel *counter;
104	/*
105	 * check if cgrp is already defined, if so we reuse it
106	 */
107	evlist__for_each_entry(evlist, counter) {
108		if (!counter->cgrp)
109			continue;
110		if (!strcmp(counter->cgrp->name, str))
111			return cgroup__get(counter->cgrp);
112	}
113
114	return NULL;
115}
116
117struct cgroup *cgroup__new(const char *name, bool do_open)
118{
119	struct cgroup *cgroup = zalloc(sizeof(*cgroup));
120
121	if (cgroup != NULL) {
122		refcount_set(&cgroup->refcnt, 1);
123
124		cgroup->name = strdup(name);
125		if (!cgroup->name)
126			goto out_err;
127
128		if (do_open) {
129			cgroup->fd = open_cgroup(name);
130			if (cgroup->fd == -1)
131				goto out_free_name;
132		} else {
133			cgroup->fd = -1;
134		}
135	}
136
137	return cgroup;
138
139out_free_name:
140	zfree(&cgroup->name);
141out_err:
142	free(cgroup);
143	return NULL;
144}
145
146struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name)
147{
148	struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
149
150	return cgroup ?: cgroup__new(name, true);
151}
152
153static int add_cgroup(struct evlist *evlist, const char *str)
154{
155	struct evsel *counter;
156	struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
157	int n;
158
159	if (!cgrp)
160		return -1;
161	/*
162	 * find corresponding event
163	 * if add cgroup N, then need to find event N
164	 */
165	n = 0;
166	evlist__for_each_entry(evlist, counter) {
167		if (n == nr_cgroups)
168			goto found;
169		n++;
170	}
171
172	cgroup__put(cgrp);
173	return -1;
174found:
175	counter->cgrp = cgrp;
176	return 0;
177}
178
179static void cgroup__delete(struct cgroup *cgroup)
180{
181	if (cgroup->fd >= 0)
182		close(cgroup->fd);
183	zfree(&cgroup->name);
184	free(cgroup);
185}
186
187void cgroup__put(struct cgroup *cgrp)
188{
189	if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
190		cgroup__delete(cgrp);
191	}
192}
193
194struct cgroup *cgroup__get(struct cgroup *cgroup)
195{
196       if (cgroup)
197		refcount_inc(&cgroup->refcnt);
198       return cgroup;
199}
200
201static void evsel__set_default_cgroup(struct evsel *evsel, struct cgroup *cgroup)
202{
203	if (evsel->cgrp == NULL)
204		evsel->cgrp = cgroup__get(cgroup);
205}
206
207void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup)
208{
209	struct evsel *evsel;
210
211	evlist__for_each_entry(evlist, evsel)
212		evsel__set_default_cgroup(evsel, cgroup);
213}
214
215/* helper function for ftw() in match_cgroups and list_cgroups */
216static int add_cgroup_name(const char *fpath, const struct stat *sb __maybe_unused,
217			   int typeflag, struct FTW *ftwbuf __maybe_unused)
218{
219	struct cgroup_name *cn;
220
221	if (typeflag != FTW_D)
222		return 0;
223
224	cn = malloc(sizeof(*cn) + strlen(fpath) + 1);
225	if (cn == NULL)
226		return -1;
227
228	cn->used = false;
229	strcpy(cn->name, fpath);
230
231	list_add_tail(&cn->list, &cgroup_list);
232	return 0;
233}
234
235static int check_and_add_cgroup_name(const char *fpath)
236{
237	struct cgroup_name *cn;
238
239	list_for_each_entry(cn, &cgroup_list, list) {
240		if (!strcmp(cn->name, fpath))
241			return 0;
242	}
243
244	/* pretend if it's added by ftw() */
245	return add_cgroup_name(fpath, NULL, FTW_D, NULL);
246}
247
248static void release_cgroup_list(void)
249{
250	struct cgroup_name *cn;
251
252	while (!list_empty(&cgroup_list)) {
253		cn = list_first_entry(&cgroup_list, struct cgroup_name, list);
254		list_del(&cn->list);
255		free(cn);
256	}
257}
258
259/* collect given cgroups only */
260static int list_cgroups(const char *str)
261{
262	const char *p, *e, *eos = str + strlen(str);
263	struct cgroup_name *cn;
264	char *s;
265
266	/* use given name as is when no regex is given */
267	for (;;) {
268		p = strchr(str, ',');
269		e = p ? p : eos;
270
271		if (e - str) {
272			int ret;
273
274			s = strndup(str, e - str);
275			if (!s)
276				return -1;
277
278			ret = check_and_add_cgroup_name(s);
279			free(s);
280			if (ret < 0)
281				return -1;
282		} else {
283			if (check_and_add_cgroup_name("/") < 0)
284				return -1;
285		}
286
287		if (!p)
288			break;
289		str = p+1;
290	}
291
292	/* these groups will be used */
293	list_for_each_entry(cn, &cgroup_list, list)
294		cn->used = true;
295
296	return 0;
297}
298
299/* collect all cgroups first and then match with the pattern */
300static int match_cgroups(const char *str)
301{
302	char mnt[PATH_MAX];
303	const char *p, *e, *eos = str + strlen(str);
304	struct cgroup_name *cn;
305	regex_t reg;
306	int prefix_len;
307	char *s;
308
309	if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event"))
310		return -1;
311
312	/* cgroup_name will have a full path, skip the root directory */
313	prefix_len = strlen(mnt);
314
315	/* collect all cgroups in the cgroup_list */
316	if (nftw(mnt, add_cgroup_name, 20, 0) < 0)
317		return -1;
318
319	for (;;) {
320		p = strchr(str, ',');
321		e = p ? p : eos;
322
323		/* allow empty cgroups, i.e., skip */
324		if (e - str) {
325			/* termination added */
326			s = strndup(str, e - str);
327			if (!s)
328				return -1;
329			if (regcomp(&reg, s, REG_NOSUB)) {
330				free(s);
331				return -1;
332			}
333
334			/* check cgroup name with the pattern */
335			list_for_each_entry(cn, &cgroup_list, list) {
336				char *name = cn->name + prefix_len;
337
338				if (name[0] == '/' && name[1])
339					name++;
340				if (!regexec(&reg, name, 0, NULL, 0))
341					cn->used = true;
342			}
343			regfree(&reg);
344			free(s);
345		} else {
346			/* first entry to root cgroup */
347			cn = list_first_entry(&cgroup_list, struct cgroup_name,
348					      list);
349			cn->used = true;
350		}
351
352		if (!p)
353			break;
354		str = p+1;
355	}
356	return prefix_len;
357}
358
359int parse_cgroups(const struct option *opt, const char *str,
360		  int unset __maybe_unused)
361{
362	struct evlist *evlist = *(struct evlist **)opt->value;
363	struct evsel *counter;
364	struct cgroup *cgrp = NULL;
365	const char *p, *e, *eos = str + strlen(str);
366	char *s;
367	int ret, i;
368
369	if (list_empty(&evlist->core.entries)) {
370		fprintf(stderr, "must define events before cgroups\n");
371		return -1;
372	}
373
374	for (;;) {
375		p = strchr(str, ',');
376		e = p ? p : eos;
377
378		/* allow empty cgroups, i.e., skip */
379		if (e - str) {
380			/* termination added */
381			s = strndup(str, e - str);
382			if (!s)
383				return -1;
384			ret = add_cgroup(evlist, s);
385			free(s);
386			if (ret)
387				return -1;
388		}
389		/* nr_cgroups is increased een for empty cgroups */
390		nr_cgroups++;
391		if (!p)
392			break;
393		str = p+1;
394	}
395	/* for the case one cgroup combine to multiple events */
396	i = 0;
397	if (nr_cgroups == 1) {
398		evlist__for_each_entry(evlist, counter) {
399			if (i == 0)
400				cgrp = counter->cgrp;
401			else {
402				counter->cgrp = cgrp;
403				refcount_inc(&cgrp->refcnt);
404			}
405			i++;
406		}
407	}
408	return 0;
409}
410
411static bool has_pattern_string(const char *str)
412{
413	return !!strpbrk(str, "{}[]()|*+?^$");
414}
415
416int evlist__expand_cgroup(struct evlist *evlist, const char *str,
417			  struct rblist *metric_events, bool open_cgroup)
418{
419	struct evlist *orig_list, *tmp_list;
420	struct evsel *pos, *evsel, *leader;
421	struct rblist orig_metric_events;
422	struct cgroup *cgrp = NULL;
423	struct cgroup_name *cn;
424	int ret = -1;
425	int prefix_len;
426
427	if (evlist->core.nr_entries == 0) {
428		fprintf(stderr, "must define events before cgroups\n");
429		return -EINVAL;
430	}
431
432	orig_list = evlist__new();
433	tmp_list = evlist__new();
434	if (orig_list == NULL || tmp_list == NULL) {
435		fprintf(stderr, "memory allocation failed\n");
436		return -ENOMEM;
437	}
438
439	/* save original events and init evlist */
440	evlist__splice_list_tail(orig_list, &evlist->core.entries);
441	evlist->core.nr_entries = 0;
442
443	if (metric_events) {
444		orig_metric_events = *metric_events;
445		rblist__init(metric_events);
446	} else {
447		rblist__init(&orig_metric_events);
448	}
449
450	if (has_pattern_string(str))
451		prefix_len = match_cgroups(str);
452	else
453		prefix_len = list_cgroups(str);
454
455	if (prefix_len < 0)
456		goto out_err;
457
458	list_for_each_entry(cn, &cgroup_list, list) {
459		char *name;
460
461		if (!cn->used)
462			continue;
463
464		/* cgroup_name might have a full path, skip the prefix */
465		name = cn->name + prefix_len;
466		if (name[0] == '/' && name[1])
467			name++;
468		cgrp = cgroup__new(name, open_cgroup);
469		if (cgrp == NULL)
470			goto out_err;
471
472		leader = NULL;
473		evlist__for_each_entry(orig_list, pos) {
474			evsel = evsel__clone(pos);
475			if (evsel == NULL)
476				goto out_err;
477
478			cgroup__put(evsel->cgrp);
479			evsel->cgrp = cgroup__get(cgrp);
480
481			if (evsel__is_group_leader(pos))
482				leader = evsel;
483			evsel__set_leader(evsel, leader);
484
485			evlist__add(tmp_list, evsel);
486		}
487		/* cgroup__new() has a refcount, release it here */
488		cgroup__put(cgrp);
489		nr_cgroups++;
490
491		if (metric_events) {
492			if (metricgroup__copy_metric_events(tmp_list, cgrp,
493							    metric_events,
494							    &orig_metric_events) < 0)
495				goto out_err;
496		}
497
498		evlist__splice_list_tail(evlist, &tmp_list->core.entries);
499		tmp_list->core.nr_entries = 0;
500	}
501
502	if (list_empty(&evlist->core.entries)) {
503		fprintf(stderr, "no cgroup matched: %s\n", str);
504		goto out_err;
505	}
506
507	ret = 0;
508	cgrp_event_expanded = true;
509
510out_err:
511	evlist__delete(orig_list);
512	evlist__delete(tmp_list);
513	rblist__exit(&orig_metric_events);
514	release_cgroup_list();
515
516	return ret;
517}
518
519static struct cgroup *__cgroup__findnew(struct rb_root *root, uint64_t id,
520					bool create, const char *path)
521{
522	struct rb_node **p = &root->rb_node;
523	struct rb_node *parent = NULL;
524	struct cgroup *cgrp;
525
526	while (*p != NULL) {
527		parent = *p;
528		cgrp = rb_entry(parent, struct cgroup, node);
529
530		if (cgrp->id == id)
531			return cgrp;
532
533		if (cgrp->id < id)
534			p = &(*p)->rb_left;
535		else
536			p = &(*p)->rb_right;
537	}
538
539	if (!create)
540		return NULL;
541
542	cgrp = malloc(sizeof(*cgrp));
543	if (cgrp == NULL)
544		return NULL;
545
546	cgrp->name = strdup(path);
547	if (cgrp->name == NULL) {
548		free(cgrp);
549		return NULL;
550	}
551
552	cgrp->fd = -1;
553	cgrp->id = id;
554	refcount_set(&cgrp->refcnt, 1);
555
556	rb_link_node(&cgrp->node, parent, p);
557	rb_insert_color(&cgrp->node, root);
558
559	return cgrp;
560}
561
562struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id,
563			       const char *path)
564{
565	struct cgroup *cgrp;
566
567	down_write(&env->cgroups.lock);
568	cgrp = __cgroup__findnew(&env->cgroups.tree, id, true, path);
569	up_write(&env->cgroups.lock);
570	return cgrp;
571}
572
573struct cgroup *__cgroup__find(struct rb_root *root, uint64_t id)
574{
575	return __cgroup__findnew(root, id, /*create=*/false, /*path=*/NULL);
576}
577
578struct cgroup *cgroup__find(struct perf_env *env, uint64_t id)
579{
580	struct cgroup *cgrp;
581
582	down_read(&env->cgroups.lock);
583	cgrp = __cgroup__findnew(&env->cgroups.tree, id, false, NULL);
584	up_read(&env->cgroups.lock);
585	return cgrp;
586}
587
588void perf_env__purge_cgroups(struct perf_env *env)
589{
590	struct rb_node *node;
591	struct cgroup *cgrp;
592
593	down_write(&env->cgroups.lock);
594	while (!RB_EMPTY_ROOT(&env->cgroups.tree)) {
595		node = rb_first(&env->cgroups.tree);
596		cgrp = rb_entry(node, struct cgroup, node);
597
598		rb_erase(node, &env->cgroups.tree);
599		cgroup__put(cgrp);
600	}
601	up_write(&env->cgroups.lock);
602}
603
604void read_all_cgroups(struct rb_root *root)
605{
606	char mnt[PATH_MAX];
607	struct cgroup_name *cn;
608	int prefix_len;
609
610	if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event"))
611		return;
612
613	/* cgroup_name will have a full path, skip the root directory */
614	prefix_len = strlen(mnt);
615
616	/* collect all cgroups in the cgroup_list */
617	if (nftw(mnt, add_cgroup_name, 20, 0) < 0)
618		return;
619
620	list_for_each_entry(cn, &cgroup_list, list) {
621		const char *name;
622		u64 cgrp_id;
623
624		/* cgroup_name might have a full path, skip the prefix */
625		name = cn->name + prefix_len;
626		if (name[0] == '\0')
627			name = "/";
628
629		cgrp_id = __read_cgroup_id(cn->name);
630		__cgroup__findnew(root, cgrp_id, /*create=*/true, name);
631	}
632
633	release_cgroup_list();
634}
635