2024-01-18 09:55 UTC+0000 ~ Jiri Olsa <jolsa@xxxxxxxxxx>
> 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.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> tools/bpf/bpftool/link.c | 71 ++++++++++++++++++++++++++++++++--------
> 1 file changed, 57 insertions(+), 14 deletions(-)
>
> diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
> index b66a1598b87c..fd862afe6c6f 100644
> --- a/tools/bpf/bpftool/link.c
> +++ b/tools/bpf/bpftool/link.c
> @@ -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 +294,17 @@ 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);
> 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 +316,13 @@ 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);
> + free(data);
> }
>
> static __u64 *u64_to_arr(__u64 val)
> @@ -675,8 +706,8 @@ 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;
> @@ -688,8 +719,11 @@ 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)
> @@ -697,12 +731,12 @@ static void show_kprobe_multi_plain(struct bpf_link_info *info)
> if (!dd.sym_count)
> return;
Don't we need to free(data) if we return here?
>
> - 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 +745,7 @@ static void show_kprobe_multi_plain(struct bpf_link_info *info)
> if (j++ == info->kprobe_multi.count)
> break;
> }
> + free(data);
> }
>
> static void show_uprobe_multi_plain(struct bpf_link_info *info)
> @@ -966,6 +1001,14 @@ 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;
> }
> }
