From e60495eafdba24a466a6ae62da86245a958954bc Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Fri, 21 Aug 2020 11:44:20 -0700 Subject: bpftool: Implement link_query for bpf iterators The link query for bpf iterators is implemented. Besides being shown to the user what bpf iterator the link represents, the target_name is also used to filter out what additional information should be printed out, e.g., whether map_id should be shown or not. The following is an example of bpf_iter link dump, plain output or pretty output. $ bpftool link show 11: iter prog 59 target_name task pids test_progs(1749) 34: iter prog 173 target_name bpf_map_elem map_id 127 pids test_progs_1(1753) $ bpftool -p link show [{ "id": 11, "type": "iter", "prog_id": 59, "target_name": "task", "pids": [{ "pid": 1749, "comm": "test_progs" } ] },{ "id": 34, "type": "iter", "prog_id": 173, "target_name": "bpf_map_elem", "map_id": 127, "pids": [{ "pid": 1753, "comm": "test_progs_1" } ] } ] Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200821184420.574430-1-yhs@fb.com --- tools/bpf/bpftool/link.c | 44 +++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 41 insertions(+), 3 deletions(-) diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c index a89f09e3c848..e77e1525d20a 100644 --- a/tools/bpf/bpftool/link.c +++ b/tools/bpf/bpftool/link.c @@ -77,6 +77,22 @@ static void show_link_attach_type_json(__u32 attach_type, json_writer_t *wtr) jsonw_uint_field(wtr, "attach_type", attach_type); } +static bool is_iter_map_target(const char *target_name) +{ + return strcmp(target_name, "bpf_map_elem") == 0 || + strcmp(target_name, "bpf_sk_storage_map") == 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); + + jsonw_string_field(wtr, "target_name", target_name); + + if (is_iter_map_target(target_name)) + jsonw_uint_field(wtr, "map_id", info->iter.map.map_id); +} + static int get_prog_info(int prog_id, struct bpf_prog_info *info) { __u32 len = sizeof(*info); @@ -128,6 +144,9 @@ static int show_link_close_json(int fd, struct bpf_link_info *info) info->cgroup.cgroup_id); show_link_attach_type_json(info->cgroup.attach_type, json_wtr); break; + case BPF_LINK_TYPE_ITER: + show_iter_json(info, json_wtr); + break; case BPF_LINK_TYPE_NETNS: jsonw_uint_field(json_wtr, "netns_ino", info->netns.netns_ino); @@ -175,6 +194,16 @@ static void show_link_attach_type_plain(__u32 attach_type) printf("attach_type %u ", attach_type); } +static void show_iter_plain(struct bpf_link_info *info) +{ + const char *target_name = u64_to_ptr(info->iter.target_name); + + printf("target_name %s ", target_name); + + if (is_iter_map_target(target_name)) + printf("map_id %u ", info->iter.map.map_id); +} + static int show_link_close_plain(int fd, struct bpf_link_info *info) { struct bpf_prog_info prog_info; @@ -204,6 +233,9 @@ static int show_link_close_plain(int fd, struct bpf_link_info *info) printf("\n\tcgroup_id %zu ", (size_t)info->cgroup.cgroup_id); show_link_attach_type_plain(info->cgroup.attach_type); break; + case BPF_LINK_TYPE_ITER: + show_iter_plain(info); + break; case BPF_LINK_TYPE_NETNS: printf("\n\tnetns_ino %u ", info->netns.netns_ino); show_link_attach_type_plain(info->netns.attach_type); @@ -231,7 +263,7 @@ static int do_show_link(int fd) { struct bpf_link_info info; __u32 len = sizeof(info); - char raw_tp_name[256]; + char buf[256]; int err; memset(&info, 0, sizeof(info)); @@ -245,8 +277,14 @@ again: } if (info.type == BPF_LINK_TYPE_RAW_TRACEPOINT && !info.raw_tracepoint.tp_name) { - info.raw_tracepoint.tp_name = (unsigned long)&raw_tp_name; - info.raw_tracepoint.tp_name_len = sizeof(raw_tp_name); + info.raw_tracepoint.tp_name = (unsigned long)&buf; + info.raw_tracepoint.tp_name_len = sizeof(buf); + goto again; + } + if (info.type == BPF_LINK_TYPE_ITER && + !info.iter.target_name) { + info.iter.target_name = (unsigned long)&buf; + info.iter.target_name_len = sizeof(buf); goto again; } -- cgit v1.2.3