linux_dsm_epyc7002/tools/lib/api/fs/cgroup.c
Namhyung Kim 7982a89851 tools lib api fs: Move cgroupsfs_find_mountpoint()
Move it from tools/perf/util/cgroup.c as it can be used by other places.
Note that cgroup filesystem is different from others since it's usually
mounted separately (in v1) for each subsystem.

I just copied the code with a little modification to pass a name of
subsystem.

Suggested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20200127100031.1368732-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-03-04 10:34:09 -03:00

68 lines
1.4 KiB
C

// 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;
}