From 188a486619e6c9d7b8531ba6c4215b31304d293f Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 15 Jan 2020 15:00:25 -0800 Subject: bpftool: Fix missing BTF output for json during map dump The btf availability check is only done for plain text output. It causes the whole BTF output went missing when json_output is used. This patch simplifies the logic a little by avoiding passing "int btf" to map_dump(). For plain text output, the btf_wtr is only created when the map has BTF (i.e. info->btf_id != 0). The nullness of "json_writer_t *wtr" in map_dump() alone can decide if dumping BTF output is needed. As long as wtr is not NULL, map_dump() will print out the BTF-described data whenever a map has BTF available (i.e. info->btf_id != 0) regardless of json or plain-text output. In do_dump(), the "int btf" is also renamed to "int do_plain_btf". Fixes: 99f9863a0c45 ("bpftool: Match maps by name") Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Cc: Paul Chaignon Link: https://lore.kernel.org/bpf/20200115230025.1101828-1-kafai@fb.com --- tools/bpf/bpftool/map.c | 42 ++++++++++++++++++++---------------------- 1 file changed, 20 insertions(+), 22 deletions(-) diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index e00e9e19d6b7..45c1eda6512c 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -933,7 +933,7 @@ static int maps_have_btf(int *fds, int nb_fds) static int map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr, - bool enable_btf, bool show_header) + bool show_header) { void *key, *value, *prev_key; unsigned int num_elems = 0; @@ -950,18 +950,16 @@ map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr, prev_key = NULL; - if (enable_btf) { - err = btf__get_from_id(info->btf_id, &btf); - if (err || !btf) { - /* enable_btf is true only if we've already checked - * that all maps have BTF information. - */ - p_err("failed to get btf"); - goto exit_free; + if (wtr) { + if (info->btf_id) { + err = btf__get_from_id(info->btf_id, &btf); + if (err || !btf) { + err = err ? : -ESRCH; + p_err("failed to get btf"); + goto exit_free; + } } - } - if (wtr) { if (show_header) { jsonw_start_object(wtr); /* map object */ show_map_header_json(info, wtr); @@ -1009,7 +1007,7 @@ static int do_dump(int argc, char **argv) { json_writer_t *wtr = NULL, *btf_wtr = NULL; struct bpf_map_info info = {}; - int nb_fds, i = 0, btf = 0; + int nb_fds, i = 0; __u32 len = sizeof(info); int *fds = NULL; int err = -1; @@ -1029,17 +1027,17 @@ static int do_dump(int argc, char **argv) if (json_output) { wtr = json_wtr; } else { - btf = maps_have_btf(fds, nb_fds); - if (btf < 0) + int do_plain_btf; + + do_plain_btf = maps_have_btf(fds, nb_fds); + if (do_plain_btf < 0) goto exit_close; - if (btf) { + + if (do_plain_btf) { btf_wtr = get_btf_writer(); - if (btf_wtr) { - wtr = btf_wtr; - } else { + wtr = btf_wtr; + if (!btf_wtr) p_info("failed to create json writer for btf. falling back to plain output"); - btf = 0; - } } } @@ -1050,7 +1048,7 @@ static int do_dump(int argc, char **argv) p_err("can't get map info: %s", strerror(errno)); break; } - err = map_dump(fds[i], &info, wtr, btf, nb_fds > 1); + err = map_dump(fds[i], &info, wtr, nb_fds > 1); if (!wtr && i != nb_fds - 1) printf("\n"); @@ -1061,7 +1059,7 @@ static int do_dump(int argc, char **argv) if (wtr && nb_fds > 1) jsonw_end_array(wtr); /* root array */ - if (btf) + if (btf_wtr) jsonw_destroy(&btf_wtr); exit_close: for (; i < nb_fds; i++) -- cgit v1.2.3-59-g8ed1b