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 <[email protected]>
Acked-by: Jakub Kicinski <[email protected]>
Cc: Quentin Monnet <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
---
tools/bpf/bpftool/cgroup.c | 170 +++++++++++++++++++++++++++++++++++++++++++--
1 file 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 <[email protected]>
+#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 @@ static int do_show(int argc, char **argv)
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 },
--
2.14.4
This commit adds a bash completion to the bpftool cgroup tree
command.
Signed-off-by: Roman Gushchin <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Quentin Monnet <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
---
tools/bpf/bpftool/bash-completion/bpftool | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
index fffd76f4998b..ce0bc0cda361 100644
--- a/tools/bpf/bpftool/bash-completion/bpftool
+++ b/tools/bpf/bpftool/bash-completion/bpftool
@@ -414,6 +414,10 @@ _bpftool()
_filedir
return 0
;;
+ tree)
+ _filedir
+ return 0
+ ;;
attach|detach)
local ATTACH_TYPES='ingress egress sock_create sock_ops \
device bind4 bind6 post_bind4 post_bind6 connect4 \
@@ -455,7 +459,7 @@ _bpftool()
*)
[[ $prev == $object ]] && \
COMPREPLY=( $( compgen -W 'help attach detach \
- show list' -- "$cur" ) )
+ show list tree' -- "$cur" ) )
;;
esac
;;
--
2.14.4
Describe cgroup tree command in the corresponding bpftool man page.
Signed-off-by: Roman Gushchin <[email protected]>
Acked-by: Jakub Kicinski <[email protected]>
Cc: Quentin Monnet <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
---
tools/bpf/bpftool/Documentation/bpftool-cgroup.rst | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/tools/bpf/bpftool/Documentation/bpftool-cgroup.rst b/tools/bpf/bpftool/Documentation/bpftool-cgroup.rst
index 7b0e6d453e92..edbe81534c6d 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-cgroup.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-cgroup.rst
@@ -15,12 +15,13 @@ SYNOPSIS
*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-f** | **--bpffs** } }
*COMMANDS* :=
- { **show** | **list** | **attach** | **detach** | **help** }
+ { **show** | **list** | **tree** | **attach** | **detach** | **help** }
MAP COMMANDS
=============
| **bpftool** **cgroup { show | list }** *CGROUP*
+| **bpftool** **cgroup tree** [*CGROUP_ROOT*]
| **bpftool** **cgroup attach** *CGROUP* *ATTACH_TYPE* *PROG* [*ATTACH_FLAGS*]
| **bpftool** **cgroup detach** *CGROUP* *ATTACH_TYPE* *PROG*
| **bpftool** **cgroup help**
@@ -39,6 +40,15 @@ DESCRIPTION
Output will start with program ID followed by attach type,
attach flags and program name.
+ **bpftool cgroup tree** [*CGROUP_ROOT*]
+ Iterate over all cgroups in *CGROUP_ROOT* and list all
+ attached programs. If *CGROUP_ROOT* is not specified,
+ bpftool uses cgroup v2 mountpoint.
+
+ The output is similar to the output of cgroup show/list
+ commands: it starts with absolute cgroup path, followed by
+ program ID, attach type, attach flags and program name.
+
**bpftool cgroup attach** *CGROUP* *ATTACH_TYPE* *PROG* [*ATTACH_FLAGS*]
Attach program *PROG* to the cgroup *CGROUP* with attach type
*ATTACH_TYPE* and optional *ATTACH_FLAGS*.
--
2.14.4
On Fri, 6 Jul 2018 14:28:16 -0700, Roman Gushchin wrote:
> This commit adds a bash completion to the bpftool cgroup tree
> command.
>
> Signed-off-by: Roman Gushchin <[email protected]>
> Cc: Jakub Kicinski <[email protected]>
> Cc: Quentin Monnet <[email protected]>
> Cc: Daniel Borkmann <[email protected]>
> Cc: Alexei Starovoitov <[email protected]>
Looks good! :)
Acked-by: Jakub Kicinski <[email protected]>
On 07/06/2018 11:28 PM, Roman Gushchin wrote:
> 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 <[email protected]>
> Acked-by: Jakub Kicinski <[email protected]>
> Cc: Quentin Monnet <[email protected]>
> Cc: Daniel Borkmann <[email protected]>
> Cc: Alexei Starovoitov <[email protected]>
Very useful! Applied to bpf-next, thanks everyone!