diff options
| author | Eduard Zingerman <eddyz87@gmail.com> | 2024-03-06 12:45:26 +0200 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2024-03-06 15:18:16 -0800 |
| commit | 6ebaa3fb88bbe4c33a0e01ce27007e1dd4fd133c (patch) | |
| tree | a57dae4f7884140f99d6b78f9a461b2b16f9f30d /tools/lib/bpf/libbpf.c | |
| parent | 5ad0ecbe056a4ea5ffaa73e58503a2f87b119a59 (diff) | |
libbpf: Rewrite btf datasec names starting from '?'
Optional struct_ops maps are defined using question mark at the start
of the section name, e.g.:
SEC("?.struct_ops")
struct test_ops optional_map = { ... };
This commit teaches libbpf to detect if kernel allows '?' prefix
in datasec names, and if it doesn't then to rewrite such names
by replacing '?' with '_', e.g.:
DATASEC ?.struct_ops -> DATASEC _.struct_ops
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240306104529.6453-13-eddyz87@gmail.com
Diffstat (limited to 'tools/lib/bpf/libbpf.c')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index ec0f508b853d..672fca94ff53 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2869,6 +2869,11 @@ static bool section_have_execinstr(struct bpf_object *obj, int idx) return sh->sh_flags & SHF_EXECINSTR; } +static bool starts_with_qmark(const char *s) +{ + return s && s[0] == '?'; +} + static bool btf_needs_sanitization(struct bpf_object *obj) { bool has_func_global = kernel_supports(obj, FEAT_BTF_GLOBAL_FUNC); @@ -2878,9 +2883,10 @@ static bool btf_needs_sanitization(struct bpf_object *obj) bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG); bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG); bool has_enum64 = kernel_supports(obj, FEAT_BTF_ENUM64); + bool has_qmark_datasec = kernel_supports(obj, FEAT_BTF_QMARK_DATASEC); return !has_func || !has_datasec || !has_func_global || !has_float || - !has_decl_tag || !has_type_tag || !has_enum64; + !has_decl_tag || !has_type_tag || !has_enum64 || !has_qmark_datasec; } static int bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) @@ -2892,6 +2898,7 @@ static int bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG); bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG); bool has_enum64 = kernel_supports(obj, FEAT_BTF_ENUM64); + bool has_qmark_datasec = kernel_supports(obj, FEAT_BTF_QMARK_DATASEC); int enum64_placeholder_id = 0; struct btf_type *t; int i, j, vlen; @@ -2918,7 +2925,7 @@ static int bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) name = (char *)btf__name_by_offset(btf, t->name_off); while (*name) { - if (*name == '.') + if (*name == '.' || *name == '?') *name = '_'; name++; } @@ -2933,6 +2940,14 @@ static int bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) vt = (void *)btf__type_by_id(btf, v->type); m->name_off = vt->name_off; } + } else if (!has_qmark_datasec && btf_is_datasec(t) && + starts_with_qmark(btf__name_by_offset(btf, t->name_off))) { + /* replace '?' prefix with '_' for DATASEC names */ + char *name; + + name = (char *)btf__name_by_offset(btf, t->name_off); + if (name[0] == '?') + name[0] = '_'; } else if (!has_func && btf_is_func_proto(t)) { /* replace FUNC_PROTO with ENUM */ vlen = btf_vlen(t); |