Commit 6bdb6d6b authored by Kui-Feng Lee's avatar Kui-Feng Lee Committed by Andrii Nakryiko
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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: default avatarKui-Feng Lee <kuifeng@fb.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarQuentin Monnet <quentin@isovalent.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Acked-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20220926184957.208194-6-kuifeng@fb.com
parent b3e1331e

tools/bpf/bpftool/link.c

+19 −0
Original line number Diff line number Diff line
@@ -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);