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authorAndrii Nakryiko <andrii@kernel.org>2021-04-23 11:13:32 -0700
committerAlexei Starovoitov <ast@kernel.org>2021-04-23 14:05:26 -0700
commit5b438f01d7eb2dc9bec7cd79de881b5f155d9a71 (patch)
tree26b0e249f1a86534e17a4743cc94b1632ff87f75 /tools
parent0dd7e456bb049ec2b5a9e00250918b346c0d17d5 (diff)
bpftool: Dump more info about DATASEC members
Dump succinct information for each member of DATASEC: its kinds and name. This is extremely helpful to see at a quick glance what is inside each DATASEC of a given BTF. Without this, one has to jump around BTF data to just find out the name of a VAR or FUNC. DATASEC's var_secinfo member is special in that regard because it doesn't itself contain the name of the member, delegating that to the referenced VAR and FUNC kinds. Other kinds, like STRUCT/UNION/FUNC/ENUM, encode member names directly and thus are clearly identifiable in BTF dump. The new output looks like this: [35] DATASEC '.bss' size=0 vlen=6 type_id=8 offset=0 size=4 (VAR 'input_bss1') type_id=13 offset=0 size=4 (VAR 'input_bss_weak') type_id=16 offset=0 size=4 (VAR 'output_bss1') type_id=17 offset=0 size=4 (VAR 'output_data1') type_id=18 offset=0 size=4 (VAR 'output_rodata1') type_id=20 offset=0 size=8 (VAR 'output_sink1') [36] DATASEC '.data' size=0 vlen=2 type_id=9 offset=0 size=4 (VAR 'input_data1') type_id=14 offset=0 size=4 (VAR 'input_data_weak') [37] DATASEC '.kconfig' size=0 vlen=2 type_id=25 offset=0 size=4 (VAR 'LINUX_KERNEL_VERSION') type_id=28 offset=0 size=1 (VAR 'CONFIG_BPF_SYSCALL') [38] DATASEC '.ksyms' size=0 vlen=1 type_id=30 offset=0 size=1 (VAR 'bpf_link_fops') [39] DATASEC '.rodata' size=0 vlen=2 type_id=12 offset=0 size=4 (VAR 'input_rodata1') type_id=15 offset=0 size=4 (VAR 'input_rodata_weak') [40] DATASEC 'license' size=0 vlen=1 type_id=24 offset=0 size=4 (VAR 'LICENSE') Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210423181348.1801389-3-andrii@kernel.org
Diffstat (limited to 'tools')
-rw-r--r--tools/bpf/bpftool/btf.c26
1 files changed, 18 insertions, 8 deletions
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
index 001749a34899..385d5c955cf3 100644
--- a/tools/bpf/bpftool/btf.c
+++ b/tools/bpf/bpftool/btf.c
@@ -100,26 +100,28 @@ static const char *btf_str(const struct btf *btf, __u32 off)
return btf__name_by_offset(btf, off) ? : "(invalid)";
}
+static int btf_kind_safe(int kind)
+{
+ return kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN;
+}
+
static int dump_btf_type(const struct btf *btf, __u32 id,
const struct btf_type *t)
{
json_writer_t *w = json_wtr;
- int kind, safe_kind;
-
- kind = BTF_INFO_KIND(t->info);
- safe_kind = kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN;
+ int kind = btf_kind(t);
if (json_output) {
jsonw_start_object(w);
jsonw_uint_field(w, "id", id);
- jsonw_string_field(w, "kind", btf_kind_str[safe_kind]);
+ jsonw_string_field(w, "kind", btf_kind_str[btf_kind_safe(kind)]);
jsonw_string_field(w, "name", btf_str(btf, t->name_off));
} else {
- printf("[%u] %s '%s'", id, btf_kind_str[safe_kind],
+ printf("[%u] %s '%s'", id, btf_kind_str[btf_kind_safe(kind)],
btf_str(btf, t->name_off));
}
- switch (BTF_INFO_KIND(t->info)) {
+ switch (kind) {
case BTF_KIND_INT: {
__u32 v = *(__u32 *)(t + 1);
const char *enc;
@@ -302,7 +304,8 @@ static int dump_btf_type(const struct btf *btf, __u32 id,
break;
}
case BTF_KIND_DATASEC: {
- const struct btf_var_secinfo *v = (const void *)(t+1);
+ const struct btf_var_secinfo *v = (const void *)(t + 1);
+ const struct btf_type *vt;
__u16 vlen = BTF_INFO_VLEN(t->info);
int i;
@@ -324,6 +327,13 @@ static int dump_btf_type(const struct btf *btf, __u32 id,
} else {
printf("\n\ttype_id=%u offset=%u size=%u",
v->type, v->offset, v->size);
+
+ if (v->type <= btf__get_nr_types(btf)) {
+ vt = btf__type_by_id(btf, v->type);
+ printf(" (%s '%s')",
+ btf_kind_str[btf_kind_safe(btf_kind(vt))],
+ btf_str(btf, vt->name_off));
+ }
}
}
if (json_output)