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authorHechao Li <hechaol@fb.com>2019-12-24 04:17:42 +0300
committerDaniel Borkmann <daniel@iogearbox.net>2019-12-26 12:35:54 +0300
commit1162f844030ac1ac7321b5e8f6c9badc7a11428f (patch)
treebf84a24566a166a5c26ebc952a28ec0be6c87f4c /tools/bpf
parent8ab9da573dad95536d8a92f19d7967e8142cd827 (diff)
downloadlinux-1162f844030ac1ac7321b5e8f6c9badc7a11428f.tar.xz
bpf: Print error message for bpftool cgroup show
Currently, when bpftool cgroup show <path> has an error, no error message is printed. This is confusing because the user may think the result is empty. Before the change: $ bpftool cgroup show /sys/fs/cgroup ID AttachType AttachFlags Name $ echo $? 255 After the change: $ ./bpftool cgroup show /sys/fs/cgroup Error: can't query bpf programs attached to /sys/fs/cgroup: Operation not permitted v2: Rename check_query_cgroup_progs to cgroup_has_attached_progs Signed-off-by: Hechao Li <hechaol@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20191224011742.3714301-1-hechaol@fb.com
Diffstat (limited to 'tools/bpf')
-rw-r--r--tools/bpf/bpftool/cgroup.c56
1 files changed, 39 insertions, 17 deletions
diff --git a/tools/bpf/bpftool/cgroup.c b/tools/bpf/bpftool/cgroup.c
index 1ef45e55039e..2f017caa678d 100644
--- a/tools/bpf/bpftool/cgroup.c
+++ b/tools/bpf/bpftool/cgroup.c
@@ -117,6 +117,25 @@ static int count_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type)
return prog_cnt;
}
+static int cgroup_has_attached_progs(int cgroup_fd)
+{
+ enum bpf_attach_type type;
+ bool no_prog = true;
+
+ for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
+ int count = count_attached_bpf_progs(cgroup_fd, type);
+
+ if (count < 0 && errno != EINVAL)
+ return -1;
+
+ if (count > 0) {
+ no_prog = false;
+ break;
+ }
+ }
+
+ return no_prog ? 0 : 1;
+}
static int show_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
int level)
{
@@ -161,6 +180,7 @@ static int show_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
static int do_show(int argc, char **argv)
{
enum bpf_attach_type type;
+ int has_attached_progs;
const char *path;
int cgroup_fd;
int ret = -1;
@@ -192,6 +212,16 @@ static int do_show(int argc, char **argv)
goto exit;
}
+ has_attached_progs = cgroup_has_attached_progs(cgroup_fd);
+ if (has_attached_progs < 0) {
+ p_err("can't query bpf programs attached to %s: %s",
+ path, strerror(errno));
+ goto exit_cgroup;
+ } else if (!has_attached_progs) {
+ ret = 0;
+ goto exit_cgroup;
+ }
+
if (json_output)
jsonw_start_array(json_wtr);
else
@@ -212,6 +242,7 @@ static int do_show(int argc, char **argv)
if (json_output)
jsonw_end_array(json_wtr);
+exit_cgroup:
close(cgroup_fd);
exit:
return ret;
@@ -228,7 +259,7 @@ 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 has_attached_progs;
int cgroup_fd;
if (typeflag != FTW_D)
@@ -240,22 +271,13 @@ static int do_show_tree_fn(const char *fpath, const struct stat *sb,
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) {
+ has_attached_progs = cgroup_has_attached_progs(cgroup_fd);
+ if (has_attached_progs < 0) {
+ p_err("can't query bpf programs attached to %s: %s",
+ fpath, strerror(errno));
+ close(cgroup_fd);
+ return SHOW_TREE_FN_ERR;
+ } else if (!has_attached_progs) {
close(cgroup_fd);
return 0;
}