diff options
author | Namhyung Kim <namhyung@kernel.org> | 2020-01-27 19:00:31 +0900 |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-03-04 10:34:09 -0300 |
commit | 7982a898515064ba180d958bfc89ed22d13905ee (patch) | |
tree | 6bdc83844fbf9854fc97c1f155f370636917afb0 /tools/lib/api/fs | |
parent | d46eec8e975a8180e178e01ba505801c44bc9a6c (diff) |
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>
Diffstat (limited to 'tools/lib/api/fs')
-rw-r--r-- | tools/lib/api/fs/Build | 1 | ||||
-rw-r--r-- | tools/lib/api/fs/cgroup.c | 67 | ||||
-rw-r--r-- | tools/lib/api/fs/fs.h | 2 |
3 files changed, 70 insertions, 0 deletions
diff --git a/tools/lib/api/fs/Build b/tools/lib/api/fs/Build index f4ed9629ae85..0f75b28654de 100644 --- a/tools/lib/api/fs/Build +++ b/tools/lib/api/fs/Build @@ -1,2 +1,3 @@ libapi-y += fs.o libapi-y += tracing_path.o +libapi-y += cgroup.o diff --git a/tools/lib/api/fs/cgroup.c b/tools/lib/api/fs/cgroup.c new file mode 100644 index 000000000000..889a6eb4aaca --- /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; +} diff --git a/tools/lib/api/fs/fs.h b/tools/lib/api/fs/fs.h index 92d03b8396b1..936edb95e1f3 100644 --- a/tools/lib/api/fs/fs.h +++ b/tools/lib/api/fs/fs.h @@ -28,6 +28,8 @@ FS(bpf_fs) #undef FS +int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys); + int filename__read_int(const char *filename, int *value); int filename__read_ull(const char *filename, unsigned long long *value); int filename__read_xll(const char *filename, unsigned long long *value); |