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>
Subject: [PATCH bpf-next 5/5] bpftool: Support dumping a map with btf_vmlinux_value_type_id
Date: Tue, 14 Jan 2020 14:44:26 -0800 [thread overview]
Message-ID: <20200114224426.3028966-1-kafai@fb.com> (raw)
In-Reply-To: <20200114224358.3027079-1-kafai@fb.com>
This patch makes bpftool support dumping a map's value properly
when the map's value type is a type of the running kernel's btf.
(i.e. map_info.btf_vmlinux_value_type_id is set instead of
map_info.btf_value_type_id). The first usecase is for the
BPF_MAP_TYPE_STRUCT_OPS.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
tools/bpf/bpftool/map.c | 43 +++++++++++++++++++++++++++++++----------
1 file changed, 33 insertions(+), 10 deletions(-)
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 4c5b15d736b6..d25f3b2355ad 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -20,6 +20,7 @@
#include "btf.h"
#include "json_writer.h"
#include "main.h"
+#include "libbpf_internal.h"
const char * const map_type_name[] = {
[BPF_MAP_TYPE_UNSPEC] = "unspec",
@@ -252,6 +253,7 @@ static int do_dump_btf(const struct btf_dumper *d,
struct bpf_map_info *map_info, void *key,
void *value)
{
+ __u32 value_id;
int ret;
/* start of key-value pair */
@@ -265,9 +267,12 @@ static int do_dump_btf(const struct btf_dumper *d,
goto err_end_obj;
}
+ value_id = map_info->btf_vmlinux_value_type_id ?
+ : map_info->btf_value_type_id;
+
if (!map_is_per_cpu(map_info->type)) {
jsonw_name(d->jw, "value");
- ret = btf_dumper_type(d, map_info->btf_value_type_id, value);
+ ret = btf_dumper_type(d, value_id, value);
} else {
unsigned int i, n, step;
@@ -279,8 +284,7 @@ static int do_dump_btf(const struct btf_dumper *d,
jsonw_start_object(d->jw);
jsonw_int_field(d->jw, "cpu", i);
jsonw_name(d->jw, "value");
- ret = btf_dumper_type(d, map_info->btf_value_type_id,
- value + i * step);
+ ret = btf_dumper_type(d, value_id, value + i * step);
jsonw_end_object(d->jw);
if (ret)
break;
@@ -932,6 +936,27 @@ static int maps_have_btf(int *fds, int nb_fds)
return 1;
}
+static struct btf *get_map_kv_btf(const struct bpf_map_info *info)
+{
+ struct btf *btf = NULL;
+
+ if (info->btf_vmlinux_value_type_id) {
+ btf = bpf_find_kernel_btf();
+ if (IS_ERR(btf))
+ p_err("failed to get kernel btf");
+ } else if (info->btf_value_type_id) {
+ int err;
+
+ err = btf__get_from_id(info->btf_id, &btf);
+ if (err || !btf) {
+ p_err("failed to get btf");
+ btf = err ? ERR_PTR(err) : ERR_PTR(-ESRCH);
+ }
+ }
+
+ return btf;
+}
+
static int
map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr,
bool show_header)
@@ -952,13 +977,11 @@ map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr,
prev_key = NULL;
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;
- }
+ btf = get_map_kv_btf(info);
+ if (IS_ERR(btf)) {
+ err = PTR_ERR(btf);
+ btf = NULL;
+ goto exit_free;
}
if (show_header) {
--
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 ` [PATCH bpf-next 2/5] bpftool: Fix missing BTF output for json during map dump Martin KaFai Lau
2020-01-15 1:34 ` 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 ` Martin KaFai Lau [this message]
2020-01-15 1:49 ` [PATCH bpf-next 5/5] bpftool: Support dumping a map with btf_vmlinux_value_type_id Andrii Nakryiko
2020-01-15 6:04 ` Martin Lau
2020-01-15 6:39 ` Andrii Nakryiko
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