bpftool: Show parameters of BPF task iterators.

Show tid or pid of iterators if giving an argument of tid or pid

For example, the command `bpftool link list` may list following
lines.

1: iter  prog 2  target_name bpf_map
2: iter  prog 3  target_name bpf_prog
33: iter  prog 225  target_name task_file  tid 1644
        pids test_progs(1644)

Link 33 is a task_file iterator with tid 1644.  For now, only targets
of task, task_file and task_vma may be with tid or pid to filter out
tasks other than those belonging to a process (pid) or a thread (tid).

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20220926184957.208194-6-kuifeng@fb.com
This commit is contained in:
Kui-Feng Lee 2022-09-26 11:49:57 -07:00 committed by Andrii Nakryiko
parent b3e1331eb9
commit 6bdb6d6be0

View File

@ -106,6 +106,13 @@ static const char *cgroup_order_string(__u32 order)
}
}
static bool is_iter_task_target(const char *target_name)
{
return strcmp(target_name, "task") == 0 ||
strcmp(target_name, "task_file") == 0 ||
strcmp(target_name, "task_vma") == 0;
}
static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr)
{
const char *target_name = u64_to_ptr(info->iter.target_name);
@ -114,6 +121,12 @@ static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr)
if (is_iter_map_target(target_name))
jsonw_uint_field(wtr, "map_id", info->iter.map.map_id);
else if (is_iter_task_target(target_name)) {
if (info->iter.task.tid)
jsonw_uint_field(wtr, "tid", info->iter.task.tid);
else if (info->iter.task.pid)
jsonw_uint_field(wtr, "pid", info->iter.task.pid);
}
if (is_iter_cgroup_target(target_name)) {
jsonw_lluint_field(wtr, "cgroup_id", info->iter.cgroup.cgroup_id);
@ -237,6 +250,12 @@ static void show_iter_plain(struct bpf_link_info *info)
if (is_iter_map_target(target_name))
printf("map_id %u ", info->iter.map.map_id);
else if (is_iter_task_target(target_name)) {
if (info->iter.task.tid)
printf("tid %u ", info->iter.task.tid);
else if (info->iter.task.pid)
printf("pid %u ", info->iter.task.pid);
}
if (is_iter_cgroup_target(target_name)) {
printf("cgroup_id %llu ", info->iter.cgroup.cgroup_id);