This source file includes following definitions.
- cgroupfs_find_mountpoint
- open_cgroup
- evlist__find_cgroup
- cgroup__new
- evlist__findnew_cgroup
- add_cgroup
- cgroup__delete
- cgroup__put
- cgroup__get
- evsel__set_default_cgroup
- evlist__set_default_cgroup
- parse_cgroups
1
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
14 int nr_cgroups;
15
16 static int
17 cgroupfs_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
30
31
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
75 static 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
94 static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str)
95 {
96 struct evsel *counter;
97
98
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
110 static 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
127 out_free_name:
128 zfree(&cgroup->name);
129 out_err:
130 free(cgroup);
131 return NULL;
132 }
133
134 struct 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
141 static 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
151
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;
162 found:
163 counter->cgrp = cgrp;
164 return 0;
165 }
166
167 static void cgroup__delete(struct cgroup *cgroup)
168 {
169 close(cgroup->fd);
170 zfree(&cgroup->name);
171 free(cgroup);
172 }
173
174 void cgroup__put(struct cgroup *cgrp)
175 {
176 if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
177 cgroup__delete(cgrp);
178 }
179 }
180
181 struct cgroup *cgroup__get(struct cgroup *cgroup)
182 {
183 if (cgroup)
184 refcount_inc(&cgroup->refcnt);
185 return cgroup;
186 }
187
188 static 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
194 void 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
202 int 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
222 if (e - str) {
223
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
233 nr_cgroups++;
234 if (!p)
235 break;
236 str = p+1;
237 }
238
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 }