From 7982a898515064ba180d958bfc89ed22d13905ee Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Mon, 27 Jan 2020 19:00:31 +0900 Subject: [PATCH] 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 Signed-off-by: Namhyung Kim Cc: Jiri Olsa Link: http://lore.kernel.org/lkml/20200127100031.1368732-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/lib/api/fs/Build | 1 + tools/lib/api/fs/cgroup.c | 67 +++++++++++++++++++++++++++++++++++++++ tools/lib/api/fs/fs.h | 2 ++ tools/perf/util/cgroup.c | 63 ++---------------------------------- 4 files changed, 72 insertions(+), 61 deletions(-) create mode 100644 tools/lib/api/fs/cgroup.c 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 +#include +#include +#include +#include +#include +#include +#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); diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c index 4881d4af3381..5bc9d3b01bd9 100644 --- a/tools/perf/util/cgroup.c +++ b/tools/perf/util/cgroup.c @@ -3,75 +3,16 @@ #include "evsel.h" #include "cgroup.h" #include "evlist.h" -#include #include #include #include #include #include #include +#include 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]; @@ -79,7 +20,7 @@ static int open_cgroup(const char *name) int fd; - if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1)) + if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event")) return -1; scnprintf(path, PATH_MAX, "%s/%s", mnt, name); -- 2.30.2