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1#include "util.h"
2#include "../perf.h"
3#include <subcmd/parse-options.h>
4#include "evsel.h"
5#include "cgroup.h"
6#include "evlist.h"
7
8int nr_cgroups;
9
10static int
11cgroupfs_find_mountpoint(char *buf, size_t maxlen)
12{
13 FILE *fp;
14 char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
15 char *token, *saved_ptr = NULL;
16 int found = 0;
17
18 fp = fopen("/proc/mounts", "r");
19 if (!fp)
20 return -1;
21
22 /*
23 * in order to handle split hierarchy, we need to scan /proc/mounts
24 * and inspect every cgroupfs mount point to find one that has
25 * perf_event subsystem
26 */
27 while (fscanf(fp, "%*s %"STR(PATH_MAX)"s %"STR(PATH_MAX)"s %"
28 STR(PATH_MAX)"s %*d %*d\n",
29 mountpoint, type, tokens) == 3) {
30
31 if (!strcmp(type, "cgroup")) {
32
33 token = strtok_r(tokens, ",", &saved_ptr);
34
35 while (token != NULL) {
36 if (!strcmp(token, "perf_event")) {
37 found = 1;
38 break;
39 }
40 token = strtok_r(NULL, ",", &saved_ptr);
41 }
42 }
43 if (found)
44 break;
45 }
46 fclose(fp);
47 if (!found)
48 return -1;
49
50 if (strlen(mountpoint) < maxlen) {
51 strcpy(buf, mountpoint);
52 return 0;
53 }
54 return -1;
55}
56
57static int open_cgroup(char *name)
58{
59 char path[PATH_MAX + 1];
60 char mnt[PATH_MAX + 1];
61 int fd;
62
63
64 if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
65 return -1;
66
67 snprintf(path, PATH_MAX, "%s/%s", mnt, name);
68
69 fd = open(path, O_RDONLY);
70 if (fd == -1)
71 fprintf(stderr, "no access to cgroup %s\n", path);
72
73 return fd;
74}
75
76static int add_cgroup(struct perf_evlist *evlist, char *str)
77{
78 struct perf_evsel *counter;
79 struct cgroup_sel *cgrp = NULL;
80 int n;
81 /*
82 * check if cgrp is already defined, if so we reuse it
83 */
84 evlist__for_each(evlist, counter) {
85 cgrp = counter->cgrp;
86 if (!cgrp)
87 continue;
88 if (!strcmp(cgrp->name, str))
89 break;
90
91 cgrp = NULL;
92 }
93
94 if (!cgrp) {
95 cgrp = zalloc(sizeof(*cgrp));
96 if (!cgrp)
97 return -1;
98
99 cgrp->name = str;
100
101 cgrp->fd = open_cgroup(str);
102 if (cgrp->fd == -1) {
103 free(cgrp);
104 return -1;
105 }
106 }
107
108 /*
109 * find corresponding event
110 * if add cgroup N, then need to find event N
111 */
112 n = 0;
113 evlist__for_each(evlist, counter) {
114 if (n == nr_cgroups)
115 goto found;
116 n++;
117 }
118 if (atomic_read(&cgrp->refcnt) == 0)
119 free(cgrp);
120
121 return -1;
122found:
123 atomic_inc(&cgrp->refcnt);
124 counter->cgrp = cgrp;
125 return 0;
126}
127
128void close_cgroup(struct cgroup_sel *cgrp)
129{
130 if (cgrp && atomic_dec_and_test(&cgrp->refcnt)) {
131 close(cgrp->fd);
132 zfree(&cgrp->name);
133 free(cgrp);
134 }
135}
136
137int parse_cgroups(const struct option *opt __maybe_unused, const char *str,
138 int unset __maybe_unused)
139{
140 struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
141 const char *p, *e, *eos = str + strlen(str);
142 char *s;
143 int ret;
144
145 if (list_empty(&evlist->entries)) {
146 fprintf(stderr, "must define events before cgroups\n");
147 return -1;
148 }
149
150 for (;;) {
151 p = strchr(str, ',');
152 e = p ? p : eos;
153
154 /* allow empty cgroups, i.e., skip */
155 if (e - str) {
156 /* termination added */
157 s = strndup(str, e - str);
158 if (!s)
159 return -1;
160 ret = add_cgroup(evlist, s);
161 if (ret) {
162 free(s);
163 return -1;
164 }
165 }
166 /* nr_cgroups is increased een for empty cgroups */
167 nr_cgroups++;
168 if (!p)
169 break;
170 str = p+1;
171 }
172 return 0;
173}
1// SPDX-License-Identifier: GPL-2.0
2#include "util.h"
3#include "../perf.h"
4#include <subcmd/parse-options.h>
5#include "evsel.h"
6#include "cgroup.h"
7#include "evlist.h"
8#include <linux/stringify.h>
9#include <sys/types.h>
10#include <sys/stat.h>
11#include <fcntl.h>
12
13int nr_cgroups;
14
15static int
16cgroupfs_find_mountpoint(char *buf, size_t maxlen)
17{
18 FILE *fp;
19 char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
20 char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path;
21 char *token, *saved_ptr = NULL;
22
23 fp = fopen("/proc/mounts", "r");
24 if (!fp)
25 return -1;
26
27 /*
28 * in order to handle split hierarchy, we need to scan /proc/mounts
29 * and inspect every cgroupfs mount point to find one that has
30 * perf_event subsystem
31 */
32 path_v1[0] = '\0';
33 path_v2[0] = '\0';
34
35 while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %"
36 __stringify(PATH_MAX)"s %*d %*d\n",
37 mountpoint, type, tokens) == 3) {
38
39 if (!path_v1[0] && !strcmp(type, "cgroup")) {
40
41 token = strtok_r(tokens, ",", &saved_ptr);
42
43 while (token != NULL) {
44 if (!strcmp(token, "perf_event")) {
45 strcpy(path_v1, mountpoint);
46 break;
47 }
48 token = strtok_r(NULL, ",", &saved_ptr);
49 }
50 }
51
52 if (!path_v2[0] && !strcmp(type, "cgroup2"))
53 strcpy(path_v2, mountpoint);
54
55 if (path_v1[0] && path_v2[0])
56 break;
57 }
58 fclose(fp);
59
60 if (path_v1[0])
61 path = path_v1;
62 else if (path_v2[0])
63 path = path_v2;
64 else
65 return -1;
66
67 if (strlen(path) < maxlen) {
68 strcpy(buf, path);
69 return 0;
70 }
71 return -1;
72}
73
74static int open_cgroup(const char *name)
75{
76 char path[PATH_MAX + 1];
77 char mnt[PATH_MAX + 1];
78 int fd;
79
80
81 if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
82 return -1;
83
84 scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
85
86 fd = open(path, O_RDONLY);
87 if (fd == -1)
88 fprintf(stderr, "no access to cgroup %s\n", path);
89
90 return fd;
91}
92
93static struct cgroup *evlist__find_cgroup(struct perf_evlist *evlist, const char *str)
94{
95 struct perf_evsel *counter;
96 struct cgroup *cgrp = NULL;
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 cgrp = cgroup__get(counter->cgrp);
105 break;
106 }
107 }
108
109 return cgrp;
110}
111
112static struct cgroup *cgroup__new(const char *name)
113{
114 struct cgroup *cgroup = zalloc(sizeof(*cgroup));
115
116 if (cgroup != NULL) {
117 refcount_set(&cgroup->refcnt, 1);
118
119 cgroup->name = strdup(name);
120 if (!cgroup->name)
121 goto out_err;
122 cgroup->fd = open_cgroup(name);
123 if (cgroup->fd == -1)
124 goto out_free_name;
125 }
126
127 return cgroup;
128
129out_free_name:
130 free(cgroup->name);
131out_err:
132 free(cgroup);
133 return NULL;
134}
135
136struct cgroup *evlist__findnew_cgroup(struct perf_evlist *evlist, const char *name)
137{
138 struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
139
140 return cgroup ?: cgroup__new(name);
141}
142
143static int add_cgroup(struct perf_evlist *evlist, const char *str)
144{
145 struct perf_evsel *counter;
146 struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
147 int n;
148
149 if (!cgrp)
150 return -1;
151 /*
152 * find corresponding event
153 * if add cgroup N, then need to find event N
154 */
155 n = 0;
156 evlist__for_each_entry(evlist, counter) {
157 if (n == nr_cgroups)
158 goto found;
159 n++;
160 }
161
162 cgroup__put(cgrp);
163 return -1;
164found:
165 counter->cgrp = cgrp;
166 return 0;
167}
168
169static void cgroup__delete(struct cgroup *cgroup)
170{
171 close(cgroup->fd);
172 zfree(&cgroup->name);
173 free(cgroup);
174}
175
176void cgroup__put(struct cgroup *cgrp)
177{
178 if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
179 cgroup__delete(cgrp);
180 }
181}
182
183struct cgroup *cgroup__get(struct cgroup *cgroup)
184{
185 if (cgroup)
186 refcount_inc(&cgroup->refcnt);
187 return cgroup;
188}
189
190static void evsel__set_default_cgroup(struct perf_evsel *evsel, struct cgroup *cgroup)
191{
192 if (evsel->cgrp == NULL)
193 evsel->cgrp = cgroup__get(cgroup);
194}
195
196void evlist__set_default_cgroup(struct perf_evlist *evlist, struct cgroup *cgroup)
197{
198 struct perf_evsel *evsel;
199
200 evlist__for_each_entry(evlist, evsel)
201 evsel__set_default_cgroup(evsel, cgroup);
202}
203
204int parse_cgroups(const struct option *opt, const char *str,
205 int unset __maybe_unused)
206{
207 struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
208 struct perf_evsel *counter;
209 struct cgroup *cgrp = NULL;
210 const char *p, *e, *eos = str + strlen(str);
211 char *s;
212 int ret, i;
213
214 if (list_empty(&evlist->entries)) {
215 fprintf(stderr, "must define events before cgroups\n");
216 return -1;
217 }
218
219 for (;;) {
220 p = strchr(str, ',');
221 e = p ? p : eos;
222
223 /* allow empty cgroups, i.e., skip */
224 if (e - str) {
225 /* termination added */
226 s = strndup(str, e - str);
227 if (!s)
228 return -1;
229 ret = add_cgroup(evlist, s);
230 free(s);
231 if (ret)
232 return -1;
233 }
234 /* nr_cgroups is increased een for empty cgroups */
235 nr_cgroups++;
236 if (!p)
237 break;
238 str = p+1;
239 }
240 /* for the case one cgroup combine to multiple events */
241 i = 0;
242 if (nr_cgroups == 1) {
243 evlist__for_each_entry(evlist, counter) {
244 if (i == 0)
245 cgrp = counter->cgrp;
246 else {
247 counter->cgrp = cgrp;
248 refcount_inc(&cgrp->refcnt);
249 }
250 i++;
251 }
252 }
253 return 0;
254}