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author | Martin KaFai Lau <kafai@fb.com> | 2018-12-13 19:41:46 +0100 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2018-12-14 23:17:34 +0100 |
commit | 23127b33ec80e656921362d7dc82a0064bac20a2 (patch) | |
tree | e60d4427daf6015702bbd039c5dfc64fc30e50e9 /kernel/bpf/btf.c | |
parent | selftests/bpf: Fix sk lookup usage in test_sock_addr (diff) | |
download | linux-23127b33ec80e656921362d7dc82a0064bac20a2.tar.xz linux-23127b33ec80e656921362d7dc82a0064bac20a2.zip |
bpf: Create a new btf_name_by_offset() for non type name use case
The current btf_name_by_offset() is returning "(anon)" type name for
the offset == 0 case and "(invalid-name-offset)" for the out-of-bound
offset case.
It fits well for the internal BTF verbose log purpose which
is focusing on type. For example,
offset == 0 => "(anon)" => anonymous type/name.
Returning non-NULL for the bad offset case is needed
during the BTF verification process because the BTF verifier may
complain about another field first before discovering the name_off
is invalid.
However, it may not be ideal for the newer use case which does not
necessary mean type name. For example, when logging line_info
in the BPF verifier in the next patch, it is better to log an
empty src line instead of logging "(anon)".
The existing bpf_name_by_offset() is renamed to __bpf_name_by_offset()
and static to btf.c.
A new bpf_name_by_offset() is added for generic context usage. It
returns "\0" for name_off == 0 (note that btf->strings[0] is "\0")
and NULL for invalid offset. It allows the caller to decide
what is the best output in its context.
The new btf_name_by_offset() is overlapped with btf_name_offset_valid().
Hence, btf_name_offset_valid() is removed from btf.h to keep the btf.h API
minimal. The existing btf_name_offset_valid() usage in btf.c could also be
replaced later.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/btf.c')
-rw-r--r-- | kernel/bpf/btf.c | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 1545ddfb6fa5..8fa0bf1c33fd 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -474,7 +474,7 @@ static bool btf_name_valid_identifier(const struct btf *btf, u32 offset) return !*src; } -const char *btf_name_by_offset(const struct btf *btf, u32 offset) +static const char *__btf_name_by_offset(const struct btf *btf, u32 offset) { if (!offset) return "(anon)"; @@ -484,6 +484,14 @@ const char *btf_name_by_offset(const struct btf *btf, u32 offset) return "(invalid-name-offset)"; } +const char *btf_name_by_offset(const struct btf *btf, u32 offset) +{ + if (offset < btf->hdr.str_len) + return &btf->strings[offset]; + + return NULL; +} + const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id) { if (type_id > btf->nr_types) @@ -576,7 +584,7 @@ __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env, __btf_verifier_log(log, "[%u] %s %s%s", env->log_type_id, btf_kind_str[kind], - btf_name_by_offset(btf, t->name_off), + __btf_name_by_offset(btf, t->name_off), log_details ? " " : ""); if (log_details) @@ -620,7 +628,7 @@ static void btf_verifier_log_member(struct btf_verifier_env *env, btf_verifier_log_type(env, struct_type, NULL); __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u", - btf_name_by_offset(btf, member->name_off), + __btf_name_by_offset(btf, member->name_off), member->type, member->offset); if (fmt && *fmt) { @@ -1872,7 +1880,7 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env, btf_verifier_log(env, "\t%s val=%d\n", - btf_name_by_offset(btf, enums[i].name_off), + __btf_name_by_offset(btf, enums[i].name_off), enums[i].val); } @@ -1896,7 +1904,8 @@ static void btf_enum_seq_show(const struct btf *btf, const struct btf_type *t, for (i = 0; i < nr_enums; i++) { if (v == enums[i].val) { seq_printf(m, "%s", - btf_name_by_offset(btf, enums[i].name_off)); + __btf_name_by_offset(btf, + enums[i].name_off)); return; } } @@ -1954,20 +1963,20 @@ static void btf_func_proto_log(struct btf_verifier_env *env, } btf_verifier_log(env, "%u %s", args[0].type, - btf_name_by_offset(env->btf, - args[0].name_off)); + __btf_name_by_offset(env->btf, + args[0].name_off)); for (i = 1; i < nr_args - 1; i++) btf_verifier_log(env, ", %u %s", args[i].type, - btf_name_by_offset(env->btf, - args[i].name_off)); + __btf_name_by_offset(env->btf, + args[i].name_off)); if (nr_args > 1) { const struct btf_param *last_arg = &args[nr_args - 1]; if (last_arg->type) btf_verifier_log(env, ", %u %s", last_arg->type, - btf_name_by_offset(env->btf, - last_arg->name_off)); + __btf_name_by_offset(env->btf, + last_arg->name_off)); else btf_verifier_log(env, ", vararg"); } |