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-rw-r--r--tools/lib/api/fs/cgroup.c67
1 files changed, 67 insertions, 0 deletions
diff --git a/tools/lib/api/fs/cgroup.c b/tools/lib/api/fs/cgroup.c
new file mode 100644
index 000000000..889a6eb4a
--- /dev/null
+++ b/tools/lib/api/fs/cgroup.c
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/stringify.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "fs.h"
+
+int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys)
+{
+ 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 (subsys && !strcmp(token, subsys)) {
+ 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;
+}