On Fri, Jun 02, 2023 at 08:52:35AM +0000, Yafang Shao wrote:
> Show the already expose kprobe_multi link info in bpftool. The result as
> follows,
> $ tools/bpf/bpftool/bpftool link show
> 1: kprobe_multi prog 5
> func_cnt 4 addrs symbols
> ffffffffb4d465b0 schedule_timeout_interruptible
> ffffffffb4d465f0 schedule_timeout_killable
> ffffffffb4d46630 schedule_timeout_uninterruptible
> ffffffffb4d46670 schedule_timeout_idle
> pids trace(8729)
>
> $ tools/bpf/bpftool/bpftool link show -j
> [{"id":1,"type":"kprobe_multi","prog_id":5,"func_cnt":4,"addrs":[{"addr":18446744072448402864,"symbol":"schedule_timeout_interruptible"},{"addr":18446744072448402928,"symbol":"schedule_timeout_killable"},{"addr":18446744072448402992,"symbol":"schedule_timeout_uninterruptible"},{"addr":18446744072448403056,"symbol":"schedule_timeout_idle"}],"pids":[{"pid":8729,"comm":"trace"}]}]
>
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> ---
> tools/bpf/bpftool/link.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 94 insertions(+)
>
> diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
> index 2d78607..3b00c07 100644
> --- a/tools/bpf/bpftool/link.c
> +++ b/tools/bpf/bpftool/link.c
> @@ -166,6 +166,57 @@ 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)
> +{
> + const __u64 *a = A, *b = B;
> +
> + return *a - *b;
> +}
> +
> +static void kprobe_multi_print_plain(__u64 addr, char *sym, __u32 indent)
> +{
> + printf("\n\t%*s %0*llx %s", indent, "", 16, addr, sym);
> +}
> +
> +static void kprobe_multi_print_json(__u64 addr, char *sym)
> +{
> + jsonw_start_object(json_wtr);
> + jsonw_uint_field(json_wtr, "addr", addr);
> + jsonw_string_field(json_wtr, "symbol", sym);
> + jsonw_end_object(json_wtr);
> +}
> +
> +static void kernel_syms_show(const __u64 *addrs, __u32 cnt, __u32 indent)
> +{
> + char buff[256], sym[256];
> + __u64 addr;
> + int i = 0;
> + FILE *fp;
> +
> + fp = fopen("/proc/kallsyms", "r");
> + if (!fp)
> + return;
> +
> + /* Each address is guaranteed to be unique. */
> + qsort((void *)addrs, cnt, sizeof(__u64), cmp_u64);
> + /* The addresses in /proc/kallsyms are already sorted. */
> + while (fgets(buff, sizeof(buff), fp)) {
> + if (sscanf(buff, "%llx %*c %s", &addr, sym) != 2)
> + continue;
> + /* The addr probed by kprobe_multi is always in
> + * /proc/kallsyms, so we can ignore some edge cases.
> + */
> + if (addr != addrs[i])
> + continue;
> + if (indent)
> + kprobe_multi_print_plain(addr, sym, indent);
> + else
> + kprobe_multi_print_json(addr, sym);
> + i++;
> + }
> + fclose(fp);
There is kernel_syms_load().
Let's reuse it instead of reimplementing kallsysm parsing?
