On Thu, Jun 8, 2023 at 3:35 AM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
>
> Show the already expose kprobe_multi link info in bpftool. The result as
> follows,
>
> $ tools/bpf/bpftool/bpftool link show
> 4: kprobe_multi prog 29
> retprobe 0 func_cnt 4
> addrs ffffffffb5d475b0 funcs schedule_timeout_interruptible
> ffffffffb5d475f0 schedule_timeout_killable
> ffffffffb5d47630 schedule_timeout_uninterruptible
> ffffffffb5d47670 schedule_timeout_idle
what about module names? kallsyms has this information and it is quite
important, in addition to function name
> pids trace(276245)
>
> $ tools/bpf/bpftool/bpftool link show -j
> [{"id":4,"type":"kprobe_multi","prog_id":29,"retprobe":0,"func_cnt":4,"funcs":[{"addr":18446744072465184176,"func":"schedule_timeout_interruptible"},{"addr":18446744072465184240,"func":"schedule_timeout_killable"},{"addr":18446744072465184304,"func":"schedule_timeout_uninterruptible"},{"addr":18446744072465184368,"func":"schedule_timeout_idle"}],"pids":[{"pid":276245,"comm":"trace"}]}]
>
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> ---
> tools/bpf/bpftool/link.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 82 insertions(+)
>
> diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
> index 2d78607..c8033c3 100644
> --- a/tools/bpf/bpftool/link.c
> +++ b/tools/bpf/bpftool/link.c
> @@ -14,6 +14,7 @@
>
> #include "json_writer.h"
> #include "main.h"
> +#include "xlated_dumper.h"
>
> static struct hashmap *link_table;
>
> @@ -166,6 +167,34 @@ static int get_prog_info(int prog_id, struct bpf_prog_info *info)
> return err;
> }
>
> +static void
> +show_kprobe_multi_json(struct bpf_link_info *info, json_writer_t *wtr)
> +{
> + struct dump_data dd = {};
> + const __u64 *addrs;
> + __u32 i;
> + int err;
> +
> + jsonw_uint_field(json_wtr, "retprobe", info->kprobe_multi.retprobe);
> + jsonw_uint_field(json_wtr, "func_cnt", info->kprobe_multi.count);
> + jsonw_name(json_wtr, "funcs");
> + jsonw_start_array(json_wtr);
> + addrs = (const __u64 *)u64_to_ptr(info->kprobe_multi.addrs);
> + err = kernel_syms_load(&dd, addrs, info->kprobe_multi.count);
> + if (err) {
> + jsonw_end_array(json_wtr);
> + return;
> + }
> + for (i = 0; i < dd.sym_count; i++) {
> + jsonw_start_object(json_wtr);
> + jsonw_uint_field(json_wtr, "addr", dd.sym_mapping[i].address);
> + jsonw_string_field(json_wtr, "func", dd.sym_mapping[i].name);
> + jsonw_end_object(json_wtr);
> + }
> + jsonw_end_array(json_wtr);
> + kernel_syms_destroy(&dd);
> +}
> +
> static int show_link_close_json(int fd, struct bpf_link_info *info)
> {
> struct bpf_prog_info prog_info;
> @@ -218,6 +247,9 @@ static int show_link_close_json(int fd, struct bpf_link_info *info)
> jsonw_uint_field(json_wtr, "map_id",
> info->struct_ops.map_id);
> break;
> + case BPF_LINK_TYPE_KPROBE_MULTI:
> + show_kprobe_multi_json(info, json_wtr);
> + break;
> default:
> break;
> }
> @@ -351,6 +383,35 @@ void netfilter_dump_plain(const struct bpf_link_info *info)
> printf(" flags 0x%x", info->netfilter.flags);
> }
>
> +static void show_kprobe_multi_plain(struct bpf_link_info *info)
> +{
> + struct dump_data dd = {};
> + const __u64 *addrs;
> + __u32 i;
> + int err;
> +
> + if (!info->kprobe_multi.count)
> + return;
> +
> + printf("\n\tretprobe %d func_cnt %u ",
> + info->kprobe_multi.retprobe, info->kprobe_multi.count);
> + addrs = (const __u64 *)u64_to_ptr(info->kprobe_multi.addrs);
> + err = kernel_syms_load(&dd, addrs, info->kprobe_multi.count);
> + if (err)
> + return;
> + for (i = 0; i < dd.sym_count; i++) {
> + if (!i)
> + printf("\n\taddrs %016lx funcs %s ",
> + dd.sym_mapping[i].address,
> + dd.sym_mapping[i].name);
> + else
> + printf("\n\t %016lx %s ",
> + dd.sym_mapping[i].address,
> + dd.sym_mapping[i].name);
> + }
> + kernel_syms_destroy(&dd);
> +}
> +
> static int show_link_close_plain(int fd, struct bpf_link_info *info)
> {
> struct bpf_prog_info prog_info;
> @@ -396,6 +457,9 @@ static int show_link_close_plain(int fd, struct bpf_link_info *info)
> case BPF_LINK_TYPE_NETFILTER:
> netfilter_dump_plain(info);
> break;
> + case BPF_LINK_TYPE_KPROBE_MULTI:
> + show_kprobe_multi_plain(info);
> + break;
> default:
> break;
> }
> @@ -417,7 +481,9 @@ static int do_show_link(int fd)
> {
> struct bpf_link_info info;
> __u32 len = sizeof(info);
> + __u64 *addrs = NULL;
> char buf[256];
> + int count;
> int err;
>
> memset(&info, 0, sizeof(info));
> @@ -441,12 +507,28 @@ static int do_show_link(int fd)
> info.iter.target_name_len = sizeof(buf);
> goto again;
> }
> + if (info.type == BPF_LINK_TYPE_KPROBE_MULTI &&
> + !info.kprobe_multi.addrs) {
> + count = info.kprobe_multi.count;
> + if (count) {
> + addrs = calloc(count, sizeof(__u64));
> + if (!addrs) {
> + p_err("mem alloc failed");
> + close(fd);
> + return -1;
> + }
> + info.kprobe_multi.addrs = (unsigned long)addrs;
> + goto again;
> + }
> + }
>
> if (json_output)
> show_link_close_json(fd, &info);
> else
> show_link_close_plain(fd, &info);
>
> + if (addrs)
> + free(addrs);
> close(fd);
> return 0;
> }
> --
> 1.8.3.1
>
