Commit b0dc0373 authored by Jiri Olsa's avatar Jiri Olsa Committed by Alexei Starovoitov
Browse files

bpftool: Display cookie for kprobe multi link 



Displaying cookies for kprobe multi link, in plain mode:

  # bpftool link
  ...
  1397: kprobe_multi  prog 47532
          kretprobe.multi  func_cnt 3
          addr             cookie           func [module]
          ffffffff82b370c0 3                bpf_fentry_test1
          ffffffff82b39780 1                bpf_fentry_test2
          ffffffff82b397a0 2                bpf_fentry_test3

And in json mode:

  # bpftool link -j | jq
  ...
    {
      "id": 1397,
      "type": "kprobe_multi",
      "prog_id": 47532,
      "retprobe": true,
      "func_cnt": 3,
      "missed": 0,
      "funcs": [
        {
          "addr": 18446744071607382208,
          "func": "bpf_fentry_test1",
          "module": null,
          "cookie": 3
        },
        {
          "addr": 18446744071607392128,
          "func": "bpf_fentry_test2",
          "module": null,
          "cookie": 1
        },
        {
          "addr": 18446744071607392160,
          "func": "bpf_fentry_test3",
          "module": null,
          "cookie": 2
        }
      ]
    }

Cookie is attached to specific address, and because we sort addresses
before printing, we need to sort cookies the same way, hence adding
the struct addr_cookie to keep and sort them together.

Also adding missing dd.sym_count check to show_kprobe_multi_json.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Acked-by: default avatarSong Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240119110505.400573-9-jolsa@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 54258324

tools/bpf/bpftool/link.c

+63 −15
Original line number Diff line number Diff line
@@ -249,18 +249,44 @@ static int get_prog_info(int prog_id, struct bpf_prog_info *info) 
	return err;

}



static int cmp_u64(const void *A, const void *B)

struct addr_cookie {

	__u64 addr;

	__u64 cookie;

};



static int cmp_addr_cookie(const void *A, const void *B)

{

	const struct addr_cookie *a = A, *b = B;



	if (a->addr == b->addr)

		return 0;

	return a->addr < b->addr ? -1 : 1;

}



static struct addr_cookie *

get_addr_cookie_array(__u64 *addrs, __u64 *cookies, __u32 count)

{

	const __u64 *a = A, *b = B;

	struct addr_cookie *data;

	__u32 i;



	return *a - *b;

	data = calloc(count, sizeof(data[0]));

	if (!data) {

		p_err("mem alloc failed");

		return NULL;

	}

	for (i = 0; i < count; i++) {

		data[i].addr = addrs[i];

		data[i].cookie = cookies[i];

	}

	qsort(data, count, sizeof(data[0]), cmp_addr_cookie);

	return data;

}



static void

show_kprobe_multi_json(struct bpf_link_info *info, json_writer_t *wtr)

{

	struct addr_cookie *data;

	__u32 i, j = 0;

	__u64 *addrs;



	jsonw_bool_field(json_wtr, "retprobe",

			 info->kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN);
@@ -268,14 +294,20 @@ show_kprobe_multi_json(struct bpf_link_info *info, json_writer_t *wtr) 
	jsonw_uint_field(json_wtr, "missed", info->kprobe_multi.missed);

	jsonw_name(json_wtr, "funcs");

	jsonw_start_array(json_wtr);

	addrs = u64_to_ptr(info->kprobe_multi.addrs);

	qsort(addrs, info->kprobe_multi.count, sizeof(addrs[0]), cmp_u64);

	data = get_addr_cookie_array(u64_to_ptr(info->kprobe_multi.addrs),

				     u64_to_ptr(info->kprobe_multi.cookies),

				     info->kprobe_multi.count);

	if (!data)

		return;



	/* Load it once for all. */

	if (!dd.sym_count)

		kernel_syms_load(&dd);

	if (!dd.sym_count)

		goto error;



	for (i = 0; i < dd.sym_count; i++) {

		if (dd.sym_mapping[i].address != addrs[j])

		if (dd.sym_mapping[i].address != data[j].addr)

			continue;

		jsonw_start_object(json_wtr);

		jsonw_uint_field(json_wtr, "addr", dd.sym_mapping[i].address);
@@ -287,11 +319,14 @@ show_kprobe_multi_json(struct bpf_link_info *info, json_writer_t *wtr) 
		} else {

			jsonw_string_field(json_wtr, "module", dd.sym_mapping[i].module);

		}

		jsonw_uint_field(json_wtr, "cookie", data[j].cookie);

		jsonw_end_object(json_wtr);

		if (j++ == info->kprobe_multi.count)

			break;

	}

	jsonw_end_array(json_wtr);

error:

	free(data);

}



static __u64 *u64_to_arr(__u64 val)
@@ -675,8 +710,8 @@ void netfilter_dump_plain(const struct bpf_link_info *info) 


static void show_kprobe_multi_plain(struct bpf_link_info *info)

{

	struct addr_cookie *data;

	__u32 i, j = 0;

	__u64 *addrs;



	if (!info->kprobe_multi.count)

		return;
@@ -688,21 +723,24 @@ static void show_kprobe_multi_plain(struct bpf_link_info *info) 
	printf("func_cnt %u  ", info->kprobe_multi.count);

	if (info->kprobe_multi.missed)

		printf("missed %llu  ", info->kprobe_multi.missed);

	addrs = (__u64 *)u64_to_ptr(info->kprobe_multi.addrs);

	qsort(addrs, info->kprobe_multi.count, sizeof(__u64), cmp_u64);

	data = get_addr_cookie_array(u64_to_ptr(info->kprobe_multi.addrs),

				     u64_to_ptr(info->kprobe_multi.cookies),

				     info->kprobe_multi.count);

	if (!data)

		return;



	/* Load it once for all. */

	if (!dd.sym_count)

		kernel_syms_load(&dd);

	if (!dd.sym_count)

		return;

		goto error;



	printf("\n\t%-16s %s", "addr", "func [module]");

	printf("\n\t%-16s %-16s %s", "addr", "cookie", "func [module]");

	for (i = 0; i < dd.sym_count; i++) {

		if (dd.sym_mapping[i].address != addrs[j])

		if (dd.sym_mapping[i].address != data[j].addr)

			continue;

		printf("\n\t%016lx %s",

		       dd.sym_mapping[i].address, dd.sym_mapping[i].name);

		printf("\n\t%016lx %-16llx %s",

		       dd.sym_mapping[i].address, data[j].cookie, dd.sym_mapping[i].name);

		if (dd.sym_mapping[i].module[0] != '\0')

			printf(" [%s]  ", dd.sym_mapping[i].module);

		else
@@ -711,6 +749,8 @@ static void show_kprobe_multi_plain(struct bpf_link_info *info) 
		if (j++ == info->kprobe_multi.count)

			break;

	}

error:

	free(data);

}



static void show_uprobe_multi_plain(struct bpf_link_info *info)
@@ -966,6 +1006,14 @@ static int do_show_link(int fd) 
				return -ENOMEM;

			}

			info.kprobe_multi.addrs = ptr_to_u64(addrs);

			cookies = calloc(count, sizeof(__u64));

			if (!cookies) {

				p_err("mem alloc failed");

				free(addrs);

				close(fd);

				return -ENOMEM;

			}

			info.kprobe_multi.cookies = ptr_to_u64(cookies);

			goto again;

		}

	}