The following example shows map pretty print with structures
which include bitfield members.
enum A { A1, A2, A3, A4, A5 };
typedef enum A ___A;
struct tmp_t {
char a1:4;
int a2:4;
int :4;
__u32 a3:4;
int b;
___A b1:4;
enum A b2:4;
};
struct bpf_map_def SEC("maps") tmpmap = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(__u32),
.value_size = sizeof(struct tmp_t),
.max_entries = 1,
};
BPF_ANNOTATE_KV_PAIR(tmpmap, int, struct tmp_t);
and the following map update in the bpf program:
key = 0;
struct tmp_t t = {};
t.a1 = 2;
t.a2 = 4;
t.a3 = 6;
t.b = 7;
t.b1 = 8;
t.b2 = 10;
bpf_map_update_elem(&tmpmap, &key, &t, 0);
With this patch, I am able to print out the map values
correctly with this patch:
bpftool map dump id 187
[{
"key": 0,
"value": {
"a1": 0x2,
"a2": 0x4,
"a3": 0x6,
"b": 7,
"b1": 0x8,
"b2": 0xa
}
}
]
The following example shows forward type can be properly
printed in function prototype with modified tst_btf_haskv.c.
struct t;
union u;
__attribute__((noinline))
static int test_long_fname_1(struct dummy_tracepoint_args *arg,
struct t *p1, union u *p2,
__u32 unused)
...
int _dummy_tracepoint(struct dummy_tracepoint_args *arg) {
return test_long_fname_1(arg, 0, 0);
}
$ bpftool p d xlated id 24
...
int test_long_fname_1(struct dummy_tracepoint_args * arg,
struct t * p1, union u * p2,
__u32 unused)
...
Signed-off-by: Yonghong Song <y...@fb.com>
---
tools/bpf/bpftool/btf_dumper.c | 36 +++++++++++++++++++++++++---------
1 file changed, 27 insertions(+), 9 deletions(-)
diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
index 6474b7555e7a..9a43e91135f7 100644
--- a/tools/bpf/bpftool/btf_dumper.c
+++ b/tools/bpf/bpftool/btf_dumper.c
@@ -190,6 +190,7 @@ static int btf_dumper_struct(const struct btf_dumper *d,
__u32 type_id,
const struct btf_type *t;
struct btf_member *m;
const void *data_off;
+ int kind_flag;
int ret = 0;
int i, vlen;
@@ -197,18 +198,32 @@ static int btf_dumper_struct(const struct btf_dumper *d,
__u32 type_id,
if (!t)
return -EINVAL;
+ kind_flag = BTF_INFO_KFLAG(t->info);
vlen = BTF_INFO_VLEN(t->info);
jsonw_start_object(d->jw);
m = (struct btf_member *)(t + 1);
for (i = 0; i < vlen; i++) {
- data_off = data + BITS_ROUNDDOWN_BYTES(m[i].offset);
+ __u32 bit_offset = m[i].offset;
+ __u32 bitfield_size = 0;
+
+ if (kind_flag) {
+ bitfield_size = BTF_MEMBER_BITFIELD_SIZE(bit_offset);
+ bit_offset = BTF_MEMBER_BIT_OFFSET(bit_offset);
+ }
+
jsonw_name(d->jw, btf__name_by_offset(d->btf, m[i].name_off));
- ret = btf_dumper_do_type(d, m[i].type,
- BITS_PER_BYTE_MASKED(m[i].offset),
- data_off);
- if (ret)
- break;
+ if (bitfield_size) {
+ btf_dumper_bitfield(bitfield_size, bit_offset,
+ data, d->jw, d->is_plain_text);
+ } else {
+ data_off = data + BITS_ROUNDDOWN_BYTES(bit_offset);
+ ret = btf_dumper_do_type(d, m[i].type,
+
BITS_PER_BYTE_MASKED(bit_offset),
+ data_off);
+ if (ret)
+ break;
+ }
}
jsonw_end_object(d->jw);
@@ -295,6 +310,7 @@ static int __btf_dumper_type_only(const struct btf *btf,
__u32 type_id,
switch (BTF_INFO_KIND(t->info)) {
case BTF_KIND_INT:
+ case BTF_KIND_TYPEDEF:
BTF_PRINT_ARG("%s ", btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_STRUCT:
@@ -318,10 +334,11 @@ static int __btf_dumper_type_only(const struct btf *btf,
__u32 type_id,
BTF_PRINT_TYPE(t->type);
BTF_PRINT_ARG("* ");
break;
- case BTF_KIND_UNKN:
case BTF_KIND_FWD:
- case BTF_KIND_TYPEDEF:
- return -1;
+ BTF_PRINT_ARG("%s %s ",
+ BTF_INFO_KFLAG(t->info) ? "union" : "struct",
+ btf__name_by_offset(btf, t->name_off));
+ break;
case BTF_KIND_VOLATILE:
BTF_PRINT_ARG("volatile ");
BTF_PRINT_TYPE(t->type);
@@ -345,6 +362,7 @@ static int __btf_dumper_type_only(const struct btf *btf,
__u32 type_id,
if (pos == -1)
return -1;
break;
+ case BTF_KIND_UNKN:
default:
return -1;
}
--
2.17.1
