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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 <linux/stringify.h>
7#include <linux/zalloc.h>
8#include <sys/types.h>
9#include <sys/stat.h>
10#include <fcntl.h>
11#include <stdlib.h>
12#include <string.h>
13
14int nr_cgroups;
15
16static int
17cgroupfs_find_mountpoint(char *buf, size_t maxlen)
18{
19 FILE *fp;
20 char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
21 char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path;
22 char *token, *saved_ptr = NULL;
23
24 fp = fopen("/proc/mounts", "r");
25 if (!fp)
26 return -1;
27
28 /*
29 * in order to handle split hierarchy, we need to scan /proc/mounts
30 * and inspect every cgroupfs mount point to find one that has
31 * perf_event subsystem
32 */
33 path_v1[0] = '\0';
34 path_v2[0] = '\0';
35
36 while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %"
37 __stringify(PATH_MAX)"s %*d %*d\n",
38 mountpoint, type, tokens) == 3) {
39
40 if (!path_v1[0] && !strcmp(type, "cgroup")) {
41
42 token = strtok_r(tokens, ",", &saved_ptr);
43
44 while (token != NULL) {
45 if (!strcmp(token, "perf_event")) {
46 strcpy(path_v1, mountpoint);
47 break;
48 }
49 token = strtok_r(NULL, ",", &saved_ptr);
50 }
51 }
52
53 if (!path_v2[0] && !strcmp(type, "cgroup2"))
54 strcpy(path_v2, mountpoint);
55
56 if (path_v1[0] && path_v2[0])
57 break;
58 }
59 fclose(fp);
60
61 if (path_v1[0])
62 path = path_v1;
63 else if (path_v2[0])
64 path = path_v2;
65 else
66 return -1;
67
68 if (strlen(path) < maxlen) {
69 strcpy(buf, path);
70 return 0;
71 }
72 return -1;
73}
74
75static int open_cgroup(const char *name)
76{
77 char path[PATH_MAX + 1];
78 char mnt[PATH_MAX + 1];
79 int fd;
80
81
82 if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
83 return -1;
84
85 scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
86
87 fd = open(path, O_RDONLY);
88 if (fd == -1)
89 fprintf(stderr, "no access to cgroup %s\n", path);
90
91 return fd;
92}
93
94static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str)
95{
96 struct evsel *counter;
97 /*
98 * check if cgrp is already defined, if so we reuse it
99 */
100 evlist__for_each_entry(evlist, counter) {
101 if (!counter->cgrp)
102 continue;
103 if (!strcmp(counter->cgrp->name, str))
104 return cgroup__get(counter->cgrp);
105 }
106
107 return NULL;
108}
109
110static struct cgroup *cgroup__new(const char *name)
111{
112 struct cgroup *cgroup = zalloc(sizeof(*cgroup));
113
114 if (cgroup != NULL) {
115 refcount_set(&cgroup->refcnt, 1);
116
117 cgroup->name = strdup(name);
118 if (!cgroup->name)
119 goto out_err;
120 cgroup->fd = open_cgroup(name);
121 if (cgroup->fd == -1)
122 goto out_free_name;
123 }
124
125 return cgroup;
126
127out_free_name:
128 zfree(&cgroup->name);
129out_err:
130 free(cgroup);
131 return NULL;
132}
133
134struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name)
135{
136 struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
137
138 return cgroup ?: cgroup__new(name);
139}
140
141static int add_cgroup(struct evlist *evlist, const char *str)
142{
143 struct evsel *counter;
144 struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
145 int n;
146
147 if (!cgrp)
148 return -1;
149 /*
150 * find corresponding event
151 * if add cgroup N, then need to find event N
152 */
153 n = 0;
154 evlist__for_each_entry(evlist, counter) {
155 if (n == nr_cgroups)
156 goto found;
157 n++;
158 }
159
160 cgroup__put(cgrp);
161 return -1;
162found:
163 counter->cgrp = cgrp;
164 return 0;
165}
166
167static void cgroup__delete(struct cgroup *cgroup)
168{
169 close(cgroup->fd);
170 zfree(&cgroup->name);
171 free(cgroup);
172}
173
174void cgroup__put(struct cgroup *cgrp)
175{
176 if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
177 cgroup__delete(cgrp);
178 }
179}
180
181struct cgroup *cgroup__get(struct cgroup *cgroup)
182{
183 if (cgroup)
184 refcount_inc(&cgroup->refcnt);
185 return cgroup;
186}
187
188static void evsel__set_default_cgroup(struct evsel *evsel, struct cgroup *cgroup)
189{
190 if (evsel->cgrp == NULL)
191 evsel->cgrp = cgroup__get(cgroup);
192}
193
194void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup)
195{
196 struct evsel *evsel;
197
198 evlist__for_each_entry(evlist, evsel)
199 evsel__set_default_cgroup(evsel, cgroup);
200}
201
202int parse_cgroups(const struct option *opt, const char *str,
203 int unset __maybe_unused)
204{
205 struct evlist *evlist = *(struct evlist **)opt->value;
206 struct evsel *counter;
207 struct cgroup *cgrp = NULL;
208 const char *p, *e, *eos = str + strlen(str);
209 char *s;
210 int ret, i;
211
212 if (list_empty(&evlist->core.entries)) {
213 fprintf(stderr, "must define events before cgroups\n");
214 return -1;
215 }
216
217 for (;;) {
218 p = strchr(str, ',');
219 e = p ? p : eos;
220
221 /* allow empty cgroups, i.e., skip */
222 if (e - str) {
223 /* termination added */
224 s = strndup(str, e - str);
225 if (!s)
226 return -1;
227 ret = add_cgroup(evlist, s);
228 free(s);
229 if (ret)
230 return -1;
231 }
232 /* nr_cgroups is increased een for empty cgroups */
233 nr_cgroups++;
234 if (!p)
235 break;
236 str = p+1;
237 }
238 /* for the case one cgroup combine to multiple events */
239 i = 0;
240 if (nr_cgroups == 1) {
241 evlist__for_each_entry(evlist, counter) {
242 if (i == 0)
243 cgrp = counter->cgrp;
244 else {
245 counter->cgrp = cgrp;
246 refcount_inc(&cgrp->refcnt);
247 }
248 i++;
249 }
250 }
251 return 0;
252}
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 <linux/zalloc.h>
7#include <sys/types.h>
8#include <sys/stat.h>
9#include <fcntl.h>
10#include <stdlib.h>
11#include <string.h>
12#include <api/fs/fs.h>
13
14int nr_cgroups;
15
16static int open_cgroup(const char *name)
17{
18 char path[PATH_MAX + 1];
19 char mnt[PATH_MAX + 1];
20 int fd;
21
22
23 if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event"))
24 return -1;
25
26 scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
27
28 fd = open(path, O_RDONLY);
29 if (fd == -1)
30 fprintf(stderr, "no access to cgroup %s\n", path);
31
32 return fd;
33}
34
35static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str)
36{
37 struct evsel *counter;
38 /*
39 * check if cgrp is already defined, if so we reuse it
40 */
41 evlist__for_each_entry(evlist, counter) {
42 if (!counter->cgrp)
43 continue;
44 if (!strcmp(counter->cgrp->name, str))
45 return cgroup__get(counter->cgrp);
46 }
47
48 return NULL;
49}
50
51static struct cgroup *cgroup__new(const char *name)
52{
53 struct cgroup *cgroup = zalloc(sizeof(*cgroup));
54
55 if (cgroup != NULL) {
56 refcount_set(&cgroup->refcnt, 1);
57
58 cgroup->name = strdup(name);
59 if (!cgroup->name)
60 goto out_err;
61 cgroup->fd = open_cgroup(name);
62 if (cgroup->fd == -1)
63 goto out_free_name;
64 }
65
66 return cgroup;
67
68out_free_name:
69 zfree(&cgroup->name);
70out_err:
71 free(cgroup);
72 return NULL;
73}
74
75struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name)
76{
77 struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
78
79 return cgroup ?: cgroup__new(name);
80}
81
82static int add_cgroup(struct evlist *evlist, const char *str)
83{
84 struct evsel *counter;
85 struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
86 int n;
87
88 if (!cgrp)
89 return -1;
90 /*
91 * find corresponding event
92 * if add cgroup N, then need to find event N
93 */
94 n = 0;
95 evlist__for_each_entry(evlist, counter) {
96 if (n == nr_cgroups)
97 goto found;
98 n++;
99 }
100
101 cgroup__put(cgrp);
102 return -1;
103found:
104 counter->cgrp = cgrp;
105 return 0;
106}
107
108static void cgroup__delete(struct cgroup *cgroup)
109{
110 if (cgroup->fd >= 0)
111 close(cgroup->fd);
112 zfree(&cgroup->name);
113 free(cgroup);
114}
115
116void cgroup__put(struct cgroup *cgrp)
117{
118 if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
119 cgroup__delete(cgrp);
120 }
121}
122
123struct cgroup *cgroup__get(struct cgroup *cgroup)
124{
125 if (cgroup)
126 refcount_inc(&cgroup->refcnt);
127 return cgroup;
128}
129
130static void evsel__set_default_cgroup(struct evsel *evsel, struct cgroup *cgroup)
131{
132 if (evsel->cgrp == NULL)
133 evsel->cgrp = cgroup__get(cgroup);
134}
135
136void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup)
137{
138 struct evsel *evsel;
139
140 evlist__for_each_entry(evlist, evsel)
141 evsel__set_default_cgroup(evsel, cgroup);
142}
143
144int parse_cgroups(const struct option *opt, const char *str,
145 int unset __maybe_unused)
146{
147 struct evlist *evlist = *(struct evlist **)opt->value;
148 struct evsel *counter;
149 struct cgroup *cgrp = NULL;
150 const char *p, *e, *eos = str + strlen(str);
151 char *s;
152 int ret, i;
153
154 if (list_empty(&evlist->core.entries)) {
155 fprintf(stderr, "must define events before cgroups\n");
156 return -1;
157 }
158
159 for (;;) {
160 p = strchr(str, ',');
161 e = p ? p : eos;
162
163 /* allow empty cgroups, i.e., skip */
164 if (e - str) {
165 /* termination added */
166 s = strndup(str, e - str);
167 if (!s)
168 return -1;
169 ret = add_cgroup(evlist, s);
170 free(s);
171 if (ret)
172 return -1;
173 }
174 /* nr_cgroups is increased een for empty cgroups */
175 nr_cgroups++;
176 if (!p)
177 break;
178 str = p+1;
179 }
180 /* for the case one cgroup combine to multiple events */
181 i = 0;
182 if (nr_cgroups == 1) {
183 evlist__for_each_entry(evlist, counter) {
184 if (i == 0)
185 cgrp = counter->cgrp;
186 else {
187 counter->cgrp = cgrp;
188 refcount_inc(&cgrp->refcnt);
189 }
190 i++;
191 }
192 }
193 return 0;
194}
195
196static struct cgroup *__cgroup__findnew(struct rb_root *root, uint64_t id,
197 bool create, const char *path)
198{
199 struct rb_node **p = &root->rb_node;
200 struct rb_node *parent = NULL;
201 struct cgroup *cgrp;
202
203 while (*p != NULL) {
204 parent = *p;
205 cgrp = rb_entry(parent, struct cgroup, node);
206
207 if (cgrp->id == id)
208 return cgrp;
209
210 if (cgrp->id < id)
211 p = &(*p)->rb_left;
212 else
213 p = &(*p)->rb_right;
214 }
215
216 if (!create)
217 return NULL;
218
219 cgrp = malloc(sizeof(*cgrp));
220 if (cgrp == NULL)
221 return NULL;
222
223 cgrp->name = strdup(path);
224 if (cgrp->name == NULL) {
225 free(cgrp);
226 return NULL;
227 }
228
229 cgrp->fd = -1;
230 cgrp->id = id;
231 refcount_set(&cgrp->refcnt, 1);
232
233 rb_link_node(&cgrp->node, parent, p);
234 rb_insert_color(&cgrp->node, root);
235
236 return cgrp;
237}
238
239struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id,
240 const char *path)
241{
242 struct cgroup *cgrp;
243
244 down_write(&env->cgroups.lock);
245 cgrp = __cgroup__findnew(&env->cgroups.tree, id, true, path);
246 up_write(&env->cgroups.lock);
247 return cgrp;
248}
249
250struct cgroup *cgroup__find(struct perf_env *env, uint64_t id)
251{
252 struct cgroup *cgrp;
253
254 down_read(&env->cgroups.lock);
255 cgrp = __cgroup__findnew(&env->cgroups.tree, id, false, NULL);
256 up_read(&env->cgroups.lock);
257 return cgrp;
258}
259
260void perf_env__purge_cgroups(struct perf_env *env)
261{
262 struct rb_node *node;
263 struct cgroup *cgrp;
264
265 down_write(&env->cgroups.lock);
266 while (!RB_EMPTY_ROOT(&env->cgroups.tree)) {
267 node = rb_first(&env->cgroups.tree);
268 cgrp = rb_entry(node, struct cgroup, node);
269
270 rb_erase(node, &env->cgroups.tree);
271 cgroup__put(cgrp);
272 }
273 up_write(&env->cgroups.lock);
274}