From: Martin KaFai Lau <kafai@fb.com>
To: <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
David Miller <davem@davemloft.net>, <kernel-team@fb.com>,
<netdev@vger.kernel.org>,
Paul Chaignon <paul.chaignon@orange.com>
Subject: [PATCH bpf-next 2/5] bpftool: Fix missing BTF output for json during map dump
Date: Tue, 14 Jan 2020 14:44:06 -0800 [thread overview]
Message-ID: <20200114224406.3027562-1-kafai@fb.com> (raw)
In-Reply-To: <20200114224358.3027079-1-kafai@fb.com>
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")
Cc: Paul Chaignon <paul.chaignon@orange.com>
Signed-off-by: Martin KaFai Lau <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++)
--
2.17.1
next prev parent reply other threads:[~2020-01-14 22:44 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 22:43 [PATCH bpf-next 0/5] bpftool: Support dumping a map with btf_vmlinux_value_type_id Martin KaFai Lau
2020-01-14 22:44 ` [PATCH bpf-next 1/5] bpftool: Fix a leak of btf object Martin KaFai Lau
2020-01-15 1:10 ` Andrii Nakryiko
2020-01-15 5:46 ` Martin Lau
2020-01-15 6:40 ` Andrii Nakryiko
2020-01-16 8:00 ` Paul Chaignon
2020-01-14 22:44 ` Martin KaFai Lau [this message]
2020-01-15 1:34 ` [PATCH bpf-next 2/5] bpftool: Fix missing BTF output for json during map dump Andrii Nakryiko
2020-01-15 5:54 ` Martin Lau
2020-01-15 6:36 ` Andrii Nakryiko
2020-01-14 22:44 ` [PATCH bpf-next 3/5] libbpf: Expose bpf_find_kernel_btf to libbpf_internal.h Martin KaFai Lau
2020-01-15 1:43 ` Andrii Nakryiko
2020-01-15 5:56 ` Martin Lau
2020-01-14 22:44 ` [PATCH bpf-next 4/5] bpftool: Add struct_ops map name Martin KaFai Lau
2020-01-15 1:45 ` Andrii Nakryiko
2020-01-14 22:44 ` [PATCH bpf-next 5/5] bpftool: Support dumping a map with btf_vmlinux_value_type_id Martin KaFai Lau
2020-01-15 1:49 ` Andrii Nakryiko
2020-01-15 6:04 ` Martin Lau
2020-01-15 6:39 ` Andrii Nakryiko
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