v4.19.13 snapshot.
diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
new file mode 100644
index 0000000..ccd0263
--- /dev/null
+++ b/tools/perf/util/cgroup.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "util.h"
+#include "../perf.h"
+#include <subcmd/parse-options.h>
+#include "evsel.h"
+#include "cgroup.h"
+#include "evlist.h"
+#include <linux/stringify.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int nr_cgroups;
+
+static int
+cgroupfs_find_mountpoint(char *buf, size_t maxlen)
+{
+ FILE *fp;
+ char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
+ char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path;
+ char *token, *saved_ptr = NULL;
+
+ fp = fopen("/proc/mounts", "r");
+ if (!fp)
+ return -1;
+
+ /*
+ * in order to handle split hierarchy, we need to scan /proc/mounts
+ * and inspect every cgroupfs mount point to find one that has
+ * perf_event subsystem
+ */
+ path_v1[0] = '\0';
+ path_v2[0] = '\0';
+
+ while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %"
+ __stringify(PATH_MAX)"s %*d %*d\n",
+ mountpoint, type, tokens) == 3) {
+
+ if (!path_v1[0] && !strcmp(type, "cgroup")) {
+
+ token = strtok_r(tokens, ",", &saved_ptr);
+
+ while (token != NULL) {
+ if (!strcmp(token, "perf_event")) {
+ strcpy(path_v1, mountpoint);
+ break;
+ }
+ token = strtok_r(NULL, ",", &saved_ptr);
+ }
+ }
+
+ if (!path_v2[0] && !strcmp(type, "cgroup2"))
+ strcpy(path_v2, mountpoint);
+
+ if (path_v1[0] && path_v2[0])
+ break;
+ }
+ fclose(fp);
+
+ if (path_v1[0])
+ path = path_v1;
+ else if (path_v2[0])
+ path = path_v2;
+ else
+ return -1;
+
+ if (strlen(path) < maxlen) {
+ strcpy(buf, path);
+ return 0;
+ }
+ return -1;
+}
+
+static int open_cgroup(const char *name)
+{
+ char path[PATH_MAX + 1];
+ char mnt[PATH_MAX + 1];
+ int fd;
+
+
+ if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
+ return -1;
+
+ scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
+
+ fd = open(path, O_RDONLY);
+ if (fd == -1)
+ fprintf(stderr, "no access to cgroup %s\n", path);
+
+ return fd;
+}
+
+static struct cgroup *evlist__find_cgroup(struct perf_evlist *evlist, const char *str)
+{
+ struct perf_evsel *counter;
+ /*
+ * check if cgrp is already defined, if so we reuse it
+ */
+ evlist__for_each_entry(evlist, counter) {
+ if (!counter->cgrp)
+ continue;
+ if (!strcmp(counter->cgrp->name, str))
+ return cgroup__get(counter->cgrp);
+ }
+
+ return NULL;
+}
+
+static struct cgroup *cgroup__new(const char *name)
+{
+ struct cgroup *cgroup = zalloc(sizeof(*cgroup));
+
+ if (cgroup != NULL) {
+ refcount_set(&cgroup->refcnt, 1);
+
+ cgroup->name = strdup(name);
+ if (!cgroup->name)
+ goto out_err;
+ cgroup->fd = open_cgroup(name);
+ if (cgroup->fd == -1)
+ goto out_free_name;
+ }
+
+ return cgroup;
+
+out_free_name:
+ free(cgroup->name);
+out_err:
+ free(cgroup);
+ return NULL;
+}
+
+struct cgroup *evlist__findnew_cgroup(struct perf_evlist *evlist, const char *name)
+{
+ struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
+
+ return cgroup ?: cgroup__new(name);
+}
+
+static int add_cgroup(struct perf_evlist *evlist, const char *str)
+{
+ struct perf_evsel *counter;
+ struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
+ int n;
+
+ if (!cgrp)
+ return -1;
+ /*
+ * find corresponding event
+ * if add cgroup N, then need to find event N
+ */
+ n = 0;
+ evlist__for_each_entry(evlist, counter) {
+ if (n == nr_cgroups)
+ goto found;
+ n++;
+ }
+
+ cgroup__put(cgrp);
+ return -1;
+found:
+ counter->cgrp = cgrp;
+ return 0;
+}
+
+static void cgroup__delete(struct cgroup *cgroup)
+{
+ close(cgroup->fd);
+ zfree(&cgroup->name);
+ free(cgroup);
+}
+
+void cgroup__put(struct cgroup *cgrp)
+{
+ if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
+ cgroup__delete(cgrp);
+ }
+}
+
+struct cgroup *cgroup__get(struct cgroup *cgroup)
+{
+ if (cgroup)
+ refcount_inc(&cgroup->refcnt);
+ return cgroup;
+}
+
+static void evsel__set_default_cgroup(struct perf_evsel *evsel, struct cgroup *cgroup)
+{
+ if (evsel->cgrp == NULL)
+ evsel->cgrp = cgroup__get(cgroup);
+}
+
+void evlist__set_default_cgroup(struct perf_evlist *evlist, struct cgroup *cgroup)
+{
+ struct perf_evsel *evsel;
+
+ evlist__for_each_entry(evlist, evsel)
+ evsel__set_default_cgroup(evsel, cgroup);
+}
+
+int parse_cgroups(const struct option *opt, const char *str,
+ int unset __maybe_unused)
+{
+ struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
+ struct perf_evsel *counter;
+ struct cgroup *cgrp = NULL;
+ const char *p, *e, *eos = str + strlen(str);
+ char *s;
+ int ret, i;
+
+ if (list_empty(&evlist->entries)) {
+ fprintf(stderr, "must define events before cgroups\n");
+ return -1;
+ }
+
+ for (;;) {
+ p = strchr(str, ',');
+ e = p ? p : eos;
+
+ /* allow empty cgroups, i.e., skip */
+ if (e - str) {
+ /* termination added */
+ s = strndup(str, e - str);
+ if (!s)
+ return -1;
+ ret = add_cgroup(evlist, s);
+ free(s);
+ if (ret)
+ return -1;
+ }
+ /* nr_cgroups is increased een for empty cgroups */
+ nr_cgroups++;
+ if (!p)
+ break;
+ str = p+1;
+ }
+ /* for the case one cgroup combine to multiple events */
+ i = 0;
+ if (nr_cgroups == 1) {
+ evlist__for_each_entry(evlist, counter) {
+ if (i == 0)
+ cgrp = counter->cgrp;
+ else {
+ counter->cgrp = cgrp;
+ refcount_inc(&cgrp->refcnt);
+ }
+ i++;
+ }
+ }
+ return 0;
+}