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authorRoman Gushchin <guro@fb.com>2018-07-07 00:28:14 +0300
committerDaniel Borkmann <daniel@iogearbox.net>2018-07-07 02:38:38 +0300
commit2058b38371d0dbd84831a085db64b996d623f81a (patch)
treea6c6dd251bc13c5b1473d4b9031c41856676565a /tools
parentab8565af68001ac5f9331daa311938ead3eb5636 (diff)
downloadlinux-2058b38371d0dbd84831a085db64b996d623f81a.tar.xz
bpftool: introduce cgroup tree command
This commit introduces a new bpftool command: cgroup tree. The idea is to iterate over the whole cgroup tree and print all attached programs. I was debugging a bpf/systemd issue, and found, that there is no simple way to listen all bpf programs attached to cgroups. I did master something in bash, but after some time got tired of it, and decided, that adding a dedicated bpftool command could be a better idea. So, here it is: $ sudo ./bpftool cgroup tree CgroupPath ID AttachType AttachFlags Name /sys/fs/cgroup/system.slice/systemd-machined.service 18 ingress 17 egress /sys/fs/cgroup/system.slice/systemd-logind.service 20 ingress 19 egress /sys/fs/cgroup/system.slice/systemd-udevd.service 16 ingress 15 egress /sys/fs/cgroup/system.slice/systemd-journald.service 14 ingress 13 egress Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> Cc: Quentin Monnet <quentin.monnet@netronome.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'tools')
-rw-r--r--tools/bpf/bpftool/cgroup.c170
1 files changed, 165 insertions, 5 deletions
diff --git a/tools/bpf/bpftool/cgroup.c b/tools/bpf/bpftool/cgroup.c
index 16bee011e16c..ee7a9765c6b3 100644
--- a/tools/bpf/bpftool/cgroup.c
+++ b/tools/bpf/bpftool/cgroup.c
@@ -2,7 +2,12 @@
// Copyright (C) 2017 Facebook
// Author: Roman Gushchin <guro@fb.com>
+#define _XOPEN_SOURCE 500
+#include <errno.h>
#include <fcntl.h>
+#include <ftw.h>
+#include <mntent.h>
+#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
@@ -53,7 +58,8 @@ static enum bpf_attach_type parse_attach_type(const char *str)
}
static int show_bpf_prog(int id, const char *attach_type_str,
- const char *attach_flags_str)
+ const char *attach_flags_str,
+ int level)
{
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
@@ -78,7 +84,8 @@ static int show_bpf_prog(int id, const char *attach_type_str,
jsonw_string_field(json_wtr, "name", info.name);
jsonw_end_object(json_wtr);
} else {
- printf("%-8u %-15s %-15s %-15s\n", info.id,
+ printf("%s%-8u %-15s %-15s %-15s\n", level ? " " : "",
+ info.id,
attach_type_str,
attach_flags_str,
info.name);
@@ -88,7 +95,20 @@ static int show_bpf_prog(int id, const char *attach_type_str,
return 0;
}
-static int show_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type)
+static int count_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type)
+{
+ __u32 prog_cnt = 0;
+ int ret;
+
+ ret = bpf_prog_query(cgroup_fd, type, 0, NULL, NULL, &prog_cnt);
+ if (ret)
+ return -1;
+
+ return prog_cnt;
+}
+
+static int show_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
+ int level)
{
__u32 prog_ids[1024] = {0};
char *attach_flags_str;
@@ -123,7 +143,7 @@ static int show_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type)
for (iter = 0; iter < prog_cnt; iter++)
show_bpf_prog(prog_ids[iter], attach_type_strings[type],
- attach_flags_str);
+ attach_flags_str, level);
return 0;
}
@@ -161,7 +181,7 @@ static int do_show(int argc, char **argv)
* If we were able to get the show for at least one
* attach type, let's return 0.
*/
- if (show_attached_bpf_progs(cgroup_fd, type) == 0)
+ if (show_attached_bpf_progs(cgroup_fd, type, 0) == 0)
ret = 0;
}
@@ -173,6 +193,143 @@ exit:
return ret;
}
+/*
+ * To distinguish nftw() errors and do_show_tree_fn() errors
+ * and avoid duplicating error messages, let's return -2
+ * from do_show_tree_fn() in case of error.
+ */
+#define NFTW_ERR -1
+#define SHOW_TREE_FN_ERR -2
+static int do_show_tree_fn(const char *fpath, const struct stat *sb,
+ int typeflag, struct FTW *ftw)
+{
+ enum bpf_attach_type type;
+ bool skip = true;
+ int cgroup_fd;
+
+ if (typeflag != FTW_D)
+ return 0;
+
+ cgroup_fd = open(fpath, O_RDONLY);
+ if (cgroup_fd < 0) {
+ p_err("can't open cgroup %s: %s", fpath, strerror(errno));
+ return SHOW_TREE_FN_ERR;
+ }
+
+ for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
+ int count = count_attached_bpf_progs(cgroup_fd, type);
+
+ if (count < 0 && errno != EINVAL) {
+ p_err("can't query bpf programs attached to %s: %s",
+ fpath, strerror(errno));
+ close(cgroup_fd);
+ return SHOW_TREE_FN_ERR;
+ }
+ if (count > 0) {
+ skip = false;
+ break;
+ }
+ }
+
+ if (skip) {
+ close(cgroup_fd);
+ return 0;
+ }
+
+ if (json_output) {
+ jsonw_start_object(json_wtr);
+ jsonw_string_field(json_wtr, "cgroup", fpath);
+ jsonw_name(json_wtr, "programs");
+ jsonw_start_array(json_wtr);
+ } else {
+ printf("%s\n", fpath);
+ }
+
+ for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++)
+ show_attached_bpf_progs(cgroup_fd, type, ftw->level);
+
+ if (json_output) {
+ jsonw_end_array(json_wtr);
+ jsonw_end_object(json_wtr);
+ }
+
+ close(cgroup_fd);
+
+ return 0;
+}
+
+static char *find_cgroup_root(void)
+{
+ struct mntent *mnt;
+ FILE *f;
+
+ f = fopen("/proc/mounts", "r");
+ if (f == NULL)
+ return NULL;
+
+ while ((mnt = getmntent(f))) {
+ if (strcmp(mnt->mnt_type, "cgroup2") == 0) {
+ fclose(f);
+ return strdup(mnt->mnt_dir);
+ }
+ }
+
+ fclose(f);
+ return NULL;
+}
+
+static int do_show_tree(int argc, char **argv)
+{
+ char *cgroup_root;
+ int ret;
+
+ switch (argc) {
+ case 0:
+ cgroup_root = find_cgroup_root();
+ if (!cgroup_root) {
+ p_err("cgroup v2 isn't mounted");
+ return -1;
+ }
+ break;
+ case 1:
+ cgroup_root = argv[0];
+ break;
+ default:
+ p_err("too many parameters for cgroup tree");
+ return -1;
+ }
+
+
+ if (json_output)
+ jsonw_start_array(json_wtr);
+ else
+ printf("%s\n"
+ "%-8s %-15s %-15s %-15s\n",
+ "CgroupPath",
+ "ID", "AttachType", "AttachFlags", "Name");
+
+ switch (nftw(cgroup_root, do_show_tree_fn, 1024, FTW_MOUNT)) {
+ case NFTW_ERR:
+ p_err("can't iterate over %s: %s", cgroup_root,
+ strerror(errno));
+ ret = -1;
+ break;
+ case SHOW_TREE_FN_ERR:
+ ret = -1;
+ break;
+ default:
+ ret = 0;
+ }
+
+ if (json_output)
+ jsonw_end_array(json_wtr);
+
+ if (argc == 0)
+ free(cgroup_root);
+
+ return ret;
+}
+
static int do_attach(int argc, char **argv)
{
enum bpf_attach_type attach_type;
@@ -289,6 +446,7 @@ static int do_help(int argc, char **argv)
fprintf(stderr,
"Usage: %s %s { show | list } CGROUP\n"
+ " %s %s tree [CGROUP_ROOT]\n"
" %s %s attach CGROUP ATTACH_TYPE PROG [ATTACH_FLAGS]\n"
" %s %s detach CGROUP ATTACH_TYPE PROG\n"
" %s %s help\n"
@@ -298,6 +456,7 @@ static int do_help(int argc, char **argv)
" " HELP_SPEC_PROGRAM "\n"
" " HELP_SPEC_OPTIONS "\n"
"",
+ bin_name, argv[-2],
bin_name, argv[-2], bin_name, argv[-2],
bin_name, argv[-2], bin_name, argv[-2]);
@@ -307,6 +466,7 @@ static int do_help(int argc, char **argv)
static const struct cmd cmds[] = {
{ "show", do_show },
{ "list", do_show },
+ { "tree", do_show_tree },
{ "attach", do_attach },
{ "detach", do_detach },
{ "help", do_help },