From 6bdb6d6be019f697296f52c37865dd7b0ce80750 Mon Sep 17 00:00:00 2001 From: Kui-Feng Lee Date: Mon, 26 Sep 2022 11:49:57 -0700 Subject: [PATCH] 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 Signed-off-by: Andrii Nakryiko Acked-by: Quentin Monnet Acked-by: Yonghong Song Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20220926184957.208194-6-kuifeng@fb.com --- tools/bpf/bpftool/link.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c index ef0dc2f8d5a2..2863639706dd 100644 --- a/tools/bpf/bpftool/link.c +++ b/tools/bpf/bpftool/link.c @@ -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);