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  
20  int nr_cgroups;
21  bool cgrp_event_expanded;
22  
23  /* used to match cgroup name with patterns */
24  struct cgroup_name {
25  	struct list_head list;
26  	bool used;
27  	char name[];
28  };
29  static LIST_HEAD(cgroup_list);
30  
open_cgroup(const char * name)31  static 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
__read_cgroup_id(const char * path)51  static 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  
read_cgroup_id(struct cgroup * cgrp)66  int 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
__read_cgroup_id(const char * path __maybe_unused)80  static 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  
cgroup_is_v2(const char * subsys)87  int 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  
evlist__find_cgroup(struct evlist * evlist,const char * str)101  static 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  
cgroup__new(const char * name,bool do_open)117  struct 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  
139  out_free_name:
140  	zfree(&cgroup->name);
141  out_err:
142  	free(cgroup);
143  	return NULL;
144  }
145  
evlist__findnew_cgroup(struct evlist * evlist,const char * name)146  struct 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  
add_cgroup(struct evlist * evlist,const char * str)153  static 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;
174  found:
175  	counter->cgrp = cgrp;
176  	return 0;
177  }
178  
cgroup__delete(struct cgroup * cgroup)179  static 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  
cgroup__put(struct cgroup * cgrp)187  void cgroup__put(struct cgroup *cgrp)
188  {
189  	if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
190  		cgroup__delete(cgrp);
191  	}
192  }
193  
cgroup__get(struct cgroup * cgroup)194  struct cgroup *cgroup__get(struct cgroup *cgroup)
195  {
196         if (cgroup)
197  		refcount_inc(&cgroup->refcnt);
198         return cgroup;
199  }
200  
evsel__set_default_cgroup(struct evsel * evsel,struct cgroup * cgroup)201  static 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  
evlist__set_default_cgroup(struct evlist * evlist,struct cgroup * cgroup)207  void 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 */
add_cgroup_name(const char * fpath,const struct stat * sb __maybe_unused,int typeflag,struct FTW * ftwbuf __maybe_unused)216  static 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  
check_and_add_cgroup_name(const char * fpath)235  static 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  
release_cgroup_list(void)248  static 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 */
list_cgroups(const char * str)260  static 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 */
match_cgroups(const char * str)300  static 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  
parse_cgroups(const struct option * opt,const char * str,int unset __maybe_unused)359  int 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  
has_pattern_string(const char * str)411  static bool has_pattern_string(const char *str)
412  {
413  	return !!strpbrk(str, "{}[]()|*+?^$");
414  }
415  
evlist__expand_cgroup(struct evlist * evlist,const char * str,struct rblist * metric_events,bool open_cgroup)416  int 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  
469  		/* the cgroup can go away in the meantime */
470  		cgrp = cgroup__new(name, open_cgroup);
471  		if (cgrp == NULL)
472  			continue;
473  
474  		leader = NULL;
475  		evlist__for_each_entry(orig_list, pos) {
476  			evsel = evsel__clone(pos);
477  			if (evsel == NULL)
478  				goto out_err;
479  
480  			cgroup__put(evsel->cgrp);
481  			evsel->cgrp = cgroup__get(cgrp);
482  
483  			if (evsel__is_group_leader(pos))
484  				leader = evsel;
485  			evsel__set_leader(evsel, leader);
486  
487  			evlist__add(tmp_list, evsel);
488  		}
489  		/* cgroup__new() has a refcount, release it here */
490  		cgroup__put(cgrp);
491  		nr_cgroups++;
492  
493  		if (metric_events) {
494  			if (metricgroup__copy_metric_events(tmp_list, cgrp,
495  							    metric_events,
496  							    &orig_metric_events) < 0)
497  				goto out_err;
498  		}
499  
500  		evlist__splice_list_tail(evlist, &tmp_list->core.entries);
501  		tmp_list->core.nr_entries = 0;
502  	}
503  
504  	if (list_empty(&evlist->core.entries)) {
505  		fprintf(stderr, "no cgroup matched: %s\n", str);
506  		goto out_err;
507  	}
508  
509  	ret = 0;
510  	cgrp_event_expanded = true;
511  
512  out_err:
513  	evlist__delete(orig_list);
514  	evlist__delete(tmp_list);
515  	rblist__exit(&orig_metric_events);
516  	release_cgroup_list();
517  
518  	return ret;
519  }
520  
__cgroup__findnew(struct rb_root * root,uint64_t id,bool create,const char * path)521  static struct cgroup *__cgroup__findnew(struct rb_root *root, uint64_t id,
522  					bool create, const char *path)
523  {
524  	struct rb_node **p = &root->rb_node;
525  	struct rb_node *parent = NULL;
526  	struct cgroup *cgrp;
527  
528  	while (*p != NULL) {
529  		parent = *p;
530  		cgrp = rb_entry(parent, struct cgroup, node);
531  
532  		if (cgrp->id == id)
533  			return cgrp;
534  
535  		if (cgrp->id < id)
536  			p = &(*p)->rb_left;
537  		else
538  			p = &(*p)->rb_right;
539  	}
540  
541  	if (!create)
542  		return NULL;
543  
544  	cgrp = malloc(sizeof(*cgrp));
545  	if (cgrp == NULL)
546  		return NULL;
547  
548  	cgrp->name = strdup(path);
549  	if (cgrp->name == NULL) {
550  		free(cgrp);
551  		return NULL;
552  	}
553  
554  	cgrp->fd = -1;
555  	cgrp->id = id;
556  	refcount_set(&cgrp->refcnt, 1);
557  
558  	rb_link_node(&cgrp->node, parent, p);
559  	rb_insert_color(&cgrp->node, root);
560  
561  	return cgrp;
562  }
563  
cgroup__findnew(struct perf_env * env,uint64_t id,const char * path)564  struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id,
565  			       const char *path)
566  {
567  	struct cgroup *cgrp;
568  
569  	down_write(&env->cgroups.lock);
570  	cgrp = __cgroup__findnew(&env->cgroups.tree, id, true, path);
571  	up_write(&env->cgroups.lock);
572  	return cgrp;
573  }
574  
__cgroup__find(struct rb_root * root,uint64_t id)575  struct cgroup *__cgroup__find(struct rb_root *root, uint64_t id)
576  {
577  	return __cgroup__findnew(root, id, /*create=*/false, /*path=*/NULL);
578  }
579  
cgroup__find(struct perf_env * env,uint64_t id)580  struct cgroup *cgroup__find(struct perf_env *env, uint64_t id)
581  {
582  	struct cgroup *cgrp;
583  
584  	down_read(&env->cgroups.lock);
585  	cgrp = __cgroup__findnew(&env->cgroups.tree, id, false, NULL);
586  	up_read(&env->cgroups.lock);
587  	return cgrp;
588  }
589  
perf_env__purge_cgroups(struct perf_env * env)590  void perf_env__purge_cgroups(struct perf_env *env)
591  {
592  	struct rb_node *node;
593  	struct cgroup *cgrp;
594  
595  	down_write(&env->cgroups.lock);
596  	while (!RB_EMPTY_ROOT(&env->cgroups.tree)) {
597  		node = rb_first(&env->cgroups.tree);
598  		cgrp = rb_entry(node, struct cgroup, node);
599  
600  		rb_erase(node, &env->cgroups.tree);
601  		cgroup__put(cgrp);
602  	}
603  	up_write(&env->cgroups.lock);
604  }
605  
read_all_cgroups(struct rb_root * root)606  void read_all_cgroups(struct rb_root *root)
607  {
608  	char mnt[PATH_MAX];
609  	struct cgroup_name *cn;
610  	int prefix_len;
611  
612  	if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event"))
613  		return;
614  
615  	/* cgroup_name will have a full path, skip the root directory */
616  	prefix_len = strlen(mnt);
617  
618  	/* collect all cgroups in the cgroup_list */
619  	if (nftw(mnt, add_cgroup_name, 20, 0) < 0)
620  		return;
621  
622  	list_for_each_entry(cn, &cgroup_list, list) {
623  		const char *name;
624  		u64 cgrp_id;
625  
626  		/* cgroup_name might have a full path, skip the prefix */
627  		name = cn->name + prefix_len;
628  		if (name[0] == '\0')
629  			name = "/";
630  
631  		cgrp_id = __read_cgroup_id(cn->name);
632  		__cgroup__findnew(root, cgrp_id, /*create=*/true, name);
633  	}
634  
635  	release_cgroup_list();
636  }
637