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authorMartin KaFai Lau <kafai@fb.com>2020-01-15 15:00:44 -0800
committerAlexei Starovoitov <ast@kernel.org>2020-01-15 15:23:27 -0800
commit4e1ea33292ff2ea0a82f52b2600abb4aba752094 (patch)
treedc987dca94677c0e814dc195fc76dba0ca1e446f /tools/bpf
parent84c72ceee91c166e19b506d618dbe9df6eacce97 (diff)
bpftool: Support dumping a map with btf_vmlinux_value_type_id
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> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200115230044.1103008-1-kafai@fb.com
Diffstat (limited to 'tools/bpf')
-rw-r--r--tools/bpf/bpftool/map.c61
1 files changed, 50 insertions, 11 deletions
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 4c5b15d736b6..86f8ab0b7e63 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -252,6 +252,7 @@ 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 +266,12 @@ 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 +283,7 @@ 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 +935,44 @@ static int maps_have_btf(int *fds, int nb_fds)
return 1;
}
+static struct btf *btf_vmlinux;
+
+static struct btf *get_map_kv_btf(const struct bpf_map_info *info)
+{
+ struct btf *btf = NULL;
+
+ if (info->btf_vmlinux_value_type_id) {
+ if (!btf_vmlinux) {
+ btf_vmlinux = libbpf_find_kernel_btf();
+ if (IS_ERR(btf_vmlinux))
+ p_err("failed to get kernel btf");
+ }
+ return btf_vmlinux;
+ } 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 void free_map_kv_btf(struct btf *btf)
+{
+ if (!IS_ERR(btf) && btf != btf_vmlinux)
+ btf__free(btf);
+}
+
+static void free_btf_vmlinux(void)
+{
+ if (!IS_ERR(btf_vmlinux))
+ btf__free(btf_vmlinux);
+}
+
static int
map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr,
bool show_header)
@@ -952,13 +993,10 @@ 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);
+ goto exit_free;
}
if (show_header) {
@@ -999,7 +1037,7 @@ exit_free:
free(key);
free(value);
close(fd);
- btf__free(btf);
+ free_map_kv_btf(btf);
return err;
}
@@ -1067,6 +1105,7 @@ exit_close:
close(fds[i]);
exit_free:
free(fds);
+ free_btf_vmlinux();
return err;
}