[PATCH bpf-next] tools/bpftool: show btf id in program information

[Prashant Bhole]

Let's add a way to know whether a program has btf context.
Patch adds 'btf_id' in the output of program listing.
When btf_id is present, it means program has btf context.

Sample output:
user@test# bpftool prog list
25: xdp  name xdp_prog1  tag 539ec6ce11b52f98  gpl
        loaded_at 2019-04-10T11:44:20+0900  uid 0
        xlated 488B  not jited  memlock 4096B  map_ids 23
        btf_id 1

Signed-off-by: Prashant Bhole <bhole_prashant...@lab.ntt.co.jp>
---
 tools/bpf/bpftool/prog.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index d2be5a06c339..81067803189e 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -249,6 +249,9 @@ static void print_prog_json(struct bpf_prog_info *info, int 
fd)
        if (info->nr_map_ids)
                show_prog_maps(fd, info->nr_map_ids);
 
+       if (info->btf_id)
+               jsonw_int_field(json_wtr, "btf_id", info->btf_id);
+
        if (!hash_empty(prog_table.table)) {
                struct pinned_obj *obj;
 
@@ -319,6 +322,9 @@ static void print_prog_plain(struct bpf_prog_info *info, 
int fd)
                }
        }
 
+       if (info->btf_id)
+               printf("\n\tbtf_id %d\n", info->btf_id);
+
        printf("\n");
 }
 
-- 
2.17.2