Re: [PATCH v3 perf,bpf 06/11] perf, bpf: save bpf_prog_info information as headers to perf.data

[Jiri Olsa]

On Fri, Feb 15, 2019 at 01:53:49PM -0800, Song Liu wrote:

SNIP

> +static int process_bpf_prog_info(struct feat_fd *ff,
> +                              void *data __maybe_unused)
> +{
> +     struct bpf_prog_info_linear *info_linear;
> +     struct bpf_prog_info_node *info_node;
> +     struct perf_env *env = &ff->ph->env;
> +     u32 count, i;
> +     int err = -1;
> +
> +     if (do_read_u32(ff, &count))
> +             return -1;
> +
> +     down_write(&env->bpf_progs.bpf_info_lock);
> +
> +     for (i = 0; i < count; ++i) {
> +             u32 info_len, data_len;
> +
> +             info_linear = NULL;
> +             info_node = NULL;
> +             if (do_read_u32(ff, &info_len))
> +                     goto out;
> +             if (do_read_u32(ff, &data_len))
> +                     goto out;
> +
> +             if (info_len > sizeof(struct bpf_prog_info)) {
> +                     pr_warning("detected invalid bpf_prog_info\n");
> +                     goto out;
> +             }
> +
> +             info_linear = malloc(sizeof(struct bpf_prog_info_linear) +
> +                                  data_len);
> +             if (!info_linear)
> +                     goto out;
> +             info_linear->info_len = sizeof(struct bpf_prog_info);
> +             info_linear->data_len = data_len;
> +             if (do_read_u64(ff, (u64 *)(&info_linear->arrays)))
> +                     goto out;
> +             if (__do_read(ff, &info_linear->info, info_len))
> +                     goto out;

hum, hows the endianity swap handled for struct bpf_prog_info?

> +             if (info_len < sizeof(struct bpf_prog_info))
> +                     memset(((void *)(&info_linear->info)) + info_len, 0,
> +                            sizeof(struct bpf_prog_info) - info_len);
> +
> +             if (__do_read(ff, info_linear->data, data_len))
> +                     goto out;

and the data?

thanks,
jirka