| Message ID | 20210416202404.3443623-7-andrii@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | BPF static linker: support externs | expand |
On 4/16/21 1:23 PM, Andrii Nakryiko wrote: > Refactor BTF-defined maps parsing logic to allow it to be nicely reused by BPF > static linker. Further, at least for BPF static linker, it's important to know > which attributes of a BPF map were defined explicitly, so provide a bit set > for each known portion of BTF map definition. This allows BPF static linker to > do a simple check when dealing with extern map declarations. > > The same capabilities allow to distinguish attributes explicitly set to zero > (e.g., __uint(max_entries, 0)) vs the case of not specifying it at all (no > max_entries attribute at all). Libbpf is currently not utilizing that, but it > could be useful for backwards compatibility reasons later. > > Signed-off-by: Andrii Nakryiko <andrii@kernel.org> > --- > tools/lib/bpf/libbpf.c | 256 ++++++++++++++++++-------------- > tools/lib/bpf/libbpf_internal.h | 32 ++++ > 2 files changed, 177 insertions(+), 111 deletions(-) > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index a0e6d6bc47f3..f6f4126389ac 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -2025,255 +2025,262 @@ static int build_map_pin_path(struct bpf_map *map, const char *path) > return bpf_map__set_pin_path(map, buf); > } > > - > -static int parse_btf_map_def(struct bpf_object *obj, > - struct bpf_map *map, > - const struct btf_type *def, > - bool strict, bool is_inner, > - const char *pin_root_path) > +int parse_btf_map_def(const char *map_name, struct btf *btf, > + const struct btf_type *def_t, bool strict, > + struct btf_map_def *map_def, struct btf_map_def *inner_def) > { > const struct btf_type *t; > const struct btf_member *m; > + bool is_inner = inner_def == NULL; > int vlen, i; > > - vlen = btf_vlen(def); > - m = btf_members(def); > + vlen = btf_vlen(def_t); > + m = btf_members(def_t); > for (i = 0; i < vlen; i++, m++) { > - const char *name = btf__name_by_offset(obj->btf, m->name_off); > + const char *name = btf__name_by_offset(btf, m->name_off); > [...] > } > else if (strcmp(name, "values") == 0) { > + char inner_map_name[128]; > int err; > > if (is_inner) { > pr_warn("map '%s': multi-level inner maps not supported.\n", > - map->name); > + map_name); > return -ENOTSUP; > } > if (i != vlen - 1) { > pr_warn("map '%s': '%s' member should be last.\n", > - map->name, name); > + map_name, name); > return -EINVAL; > } > - if (!bpf_map_type__is_map_in_map(map->def.type)) { > + if (!bpf_map_type__is_map_in_map(map_def->map_type)) { > pr_warn("map '%s': should be map-in-map.\n", > - map->name); > + map_name); > return -ENOTSUP; > } > - if (map->def.value_size && map->def.value_size != 4) { > + if (map_def->value_size && map_def->value_size != 4) { > pr_warn("map '%s': conflicting value size %u != 4.\n", > - map->name, map->def.value_size); > + map_name, map_def->value_size); > return -EINVAL; > } > - map->def.value_size = 4; > - t = btf__type_by_id(obj->btf, m->type); > + map_def->value_size = 4; > + t = btf__type_by_id(btf, m->type); > if (!t) { > pr_warn("map '%s': map-in-map inner type [%d] not found.\n", > - map->name, m->type); > + map_name, m->type); > return -EINVAL; > } > if (!btf_is_array(t) || btf_array(t)->nelems) { > pr_warn("map '%s': map-in-map inner spec is not a zero-sized array.\n", > - map->name); > + map_name); > return -EINVAL; > } > - t = skip_mods_and_typedefs(obj->btf, btf_array(t)->type, > - NULL); > + t = skip_mods_and_typedefs(btf, btf_array(t)->type, NULL); > if (!btf_is_ptr(t)) { > pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", > - map->name, btf_kind_str(t)); > + map_name, btf_kind_str(t)); > return -EINVAL; > } > - t = skip_mods_and_typedefs(obj->btf, t->type, NULL); > + t = skip_mods_and_typedefs(btf, t->type, NULL); > if (!btf_is_struct(t)) { > pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", > - map->name, btf_kind_str(t)); > + map_name, btf_kind_str(t)); > return -EINVAL; > } > > - map->inner_map = calloc(1, sizeof(*map->inner_map)); > - if (!map->inner_map) > - return -ENOMEM; > - map->inner_map->fd = -1; > - map->inner_map->sec_idx = obj->efile.btf_maps_shndx; The refactoring didn't set map->inner_map->sec_idx. I guess since inner_map is only used internally by libbpf, so it does not have a user visible sec_idx and hence useless? It is worthwhile to mention in the commit message for this difference, I think. > - map->inner_map->name = malloc(strlen(map->name) + > - sizeof(".inner") + 1); > - if (!map->inner_map->name) > - return -ENOMEM; > - sprintf(map->inner_map->name, "%s.inner", map->name); > - > - err = parse_btf_map_def(obj, map->inner_map, t, strict, > - true /* is_inner */, NULL); > + snprintf(inner_map_name, sizeof(inner_map_name), "%s.inner", map_name); > + err = parse_btf_map_def(inner_map_name, btf, t, strict, inner_def, NULL); > if (err) > return err; > + > + map_def->parts |= MAP_DEF_INNER_MAP; > } else if (strcmp(name, "pinning") == 0) { > __u32 val; > - int err; > > if (is_inner) { > - pr_debug("map '%s': inner def can't be pinned.\n", > - map->name); > + pr_warn("map '%s': inner def can't be pinned.\n", map_name); > return -EINVAL; > } > - if (!get_map_field_int(map->name, obj->btf, m, &val)) > + if (!get_map_field_int(map_name, btf, m, &val)) > return -EINVAL; > - pr_debug("map '%s': found pinning = %u.\n", > - map->name, val); > - > - if (val != LIBBPF_PIN_NONE && > - val != LIBBPF_PIN_BY_NAME) { > + if (val != LIBBPF_PIN_NONE && val != LIBBPF_PIN_BY_NAME) { > pr_warn("map '%s': invalid pinning value %u.\n", > - map->name, val); > + map_name, val); > return -EINVAL; > } > - if (val == LIBBPF_PIN_BY_NAME) { > - err = build_map_pin_path(map, pin_root_path); > - if (err) { > - pr_warn("map '%s': couldn't build pin path.\n", > - map->name); > - return err; > - } > - } > + map_def->pinning = val; > + map_def->parts |= MAP_DEF_PINNING; > } else { > if (strict) { > - pr_warn("map '%s': unknown field '%s'.\n", > - map->name, name); > + pr_warn("map '%s': unknown field '%s'.\n", map_name, name); > return -ENOTSUP; > } > - pr_debug("map '%s': ignoring unknown field '%s'.\n", > - map->name, name); > + pr_debug("map '%s': ignoring unknown field '%s'.\n", map_name, name); > } > } > > - if (map->def.type == BPF_MAP_TYPE_UNSPEC) { > - pr_warn("map '%s': map type isn't specified.\n", map->name); > + if (map_def->map_type == BPF_MAP_TYPE_UNSPEC) { > + pr_warn("map '%s': map type isn't specified.\n", map_name); > return -EINVAL; > } > > return 0; > } > > +static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def) > +{ [...] > +} > + > static int bpf_object__init_user_btf_map(struct bpf_object *obj, > const struct btf_type *sec, > int var_idx, int sec_idx, > const Elf_Data *data, bool strict, > const char *pin_root_path) > { > + struct btf_map_def map_def = {}, inner_def = {}; > const struct btf_type *var, *def; > const struct btf_var_secinfo *vi; > const struct btf_var *var_extra; > const char *map_name; > struct bpf_map *map; > + int err; > > vi = btf_var_secinfos(sec) + var_idx; > var = btf__type_by_id(obj->btf, vi->type); > @@ -2327,7 +2334,34 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj, > pr_debug("map '%s': at sec_idx %d, offset %zu.\n", > map_name, map->sec_idx, map->sec_offset); > > - return parse_btf_map_def(obj, map, def, strict, false, pin_root_path); > + err = parse_btf_map_def(map->name, obj->btf, def, strict, &map_def, &inner_def); > + if (err) > + return err; > + > + fill_map_from_def(map, &map_def); > + > + if (map_def.pinning == LIBBPF_PIN_BY_NAME) { > + err = build_map_pin_path(map, pin_root_path); > + if (err) { > + pr_warn("map '%s': couldn't build pin path.\n", map->name); > + return err; > + } > + } > + > + if (map_def.parts & MAP_DEF_INNER_MAP) { > + map->inner_map = calloc(1, sizeof(*map->inner_map)); > + if (!map->inner_map) > + return -ENOMEM; > + map->inner_map->fd = -1; missing set map->inner_map->sec_idx here. > + map->inner_map->name = malloc(strlen(map_name) + sizeof(".inner") + 1); > + if (!map->inner_map->name) > + return -ENOMEM; > + sprintf(map->inner_map->name, "%s.inner", map_name); > + > + fill_map_from_def(map->inner_map, &inner_def); > + } > + > + return 0; > } > > static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict, > diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h > index 92b7eae10c6d..17883073710c 100644 > --- a/tools/lib/bpf/libbpf_internal.h > +++ b/tools/lib/bpf/libbpf_internal.h > @@ -138,6 +138,38 @@ static inline __u32 btf_type_info(int kind, int vlen, int kflag) > return (kflag << 31) | (kind << 24) | vlen; > } > [...]
On Thu, Apr 22, 2021 at 8:33 AM Yonghong Song <yhs@fb.com> wrote: > > > > On 4/16/21 1:23 PM, Andrii Nakryiko wrote: > > Refactor BTF-defined maps parsing logic to allow it to be nicely reused by BPF > > static linker. Further, at least for BPF static linker, it's important to know > > which attributes of a BPF map were defined explicitly, so provide a bit set > > for each known portion of BTF map definition. This allows BPF static linker to > > do a simple check when dealing with extern map declarations. > > > > The same capabilities allow to distinguish attributes explicitly set to zero > > (e.g., __uint(max_entries, 0)) vs the case of not specifying it at all (no > > max_entries attribute at all). Libbpf is currently not utilizing that, but it > > could be useful for backwards compatibility reasons later. > > > > Signed-off-by: Andrii Nakryiko <andrii@kernel.org> > > --- > > tools/lib/bpf/libbpf.c | 256 ++++++++++++++++++-------------- > > tools/lib/bpf/libbpf_internal.h | 32 ++++ > > 2 files changed, 177 insertions(+), 111 deletions(-) > > > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > > index a0e6d6bc47f3..f6f4126389ac 100644 > > --- a/tools/lib/bpf/libbpf.c > > +++ b/tools/lib/bpf/libbpf.c > > @@ -2025,255 +2025,262 @@ static int build_map_pin_path(struct bpf_map *map, const char *path) > > return bpf_map__set_pin_path(map, buf); > > } > > > > - > > -static int parse_btf_map_def(struct bpf_object *obj, > > - struct bpf_map *map, > > - const struct btf_type *def, > > - bool strict, bool is_inner, > > - const char *pin_root_path) > > +int parse_btf_map_def(const char *map_name, struct btf *btf, > > + const struct btf_type *def_t, bool strict, > > + struct btf_map_def *map_def, struct btf_map_def *inner_def) > > { > > const struct btf_type *t; > > const struct btf_member *m; > > + bool is_inner = inner_def == NULL; > > int vlen, i; > > > > - vlen = btf_vlen(def); > > - m = btf_members(def); > > + vlen = btf_vlen(def_t); > > + m = btf_members(def_t); > > for (i = 0; i < vlen; i++, m++) { > > - const char *name = btf__name_by_offset(obj->btf, m->name_off); > > + const char *name = btf__name_by_offset(btf, m->name_off); > > > [...] > > } > > else if (strcmp(name, "values") == 0) { > > + char inner_map_name[128]; > > int err; > > > > if (is_inner) { > > pr_warn("map '%s': multi-level inner maps not supported.\n", > > - map->name); > > + map_name); > > return -ENOTSUP; > > } > > if (i != vlen - 1) { > > pr_warn("map '%s': '%s' member should be last.\n", > > - map->name, name); > > + map_name, name); > > return -EINVAL; > > } > > - if (!bpf_map_type__is_map_in_map(map->def.type)) { > > + if (!bpf_map_type__is_map_in_map(map_def->map_type)) { > > pr_warn("map '%s': should be map-in-map.\n", > > - map->name); > > + map_name); > > return -ENOTSUP; > > } > > - if (map->def.value_size && map->def.value_size != 4) { > > + if (map_def->value_size && map_def->value_size != 4) { > > pr_warn("map '%s': conflicting value size %u != 4.\n", > > - map->name, map->def.value_size); > > + map_name, map_def->value_size); > > return -EINVAL; > > } > > - map->def.value_size = 4; > > - t = btf__type_by_id(obj->btf, m->type); > > + map_def->value_size = 4; > > + t = btf__type_by_id(btf, m->type); > > if (!t) { > > pr_warn("map '%s': map-in-map inner type [%d] not found.\n", > > - map->name, m->type); > > + map_name, m->type); > > return -EINVAL; > > } > > if (!btf_is_array(t) || btf_array(t)->nelems) { > > pr_warn("map '%s': map-in-map inner spec is not a zero-sized array.\n", > > - map->name); > > + map_name); > > return -EINVAL; > > } > > - t = skip_mods_and_typedefs(obj->btf, btf_array(t)->type, > > - NULL); > > + t = skip_mods_and_typedefs(btf, btf_array(t)->type, NULL); > > if (!btf_is_ptr(t)) { > > pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", > > - map->name, btf_kind_str(t)); > > + map_name, btf_kind_str(t)); > > return -EINVAL; > > } > > - t = skip_mods_and_typedefs(obj->btf, t->type, NULL); > > + t = skip_mods_and_typedefs(btf, t->type, NULL); > > if (!btf_is_struct(t)) { > > pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", > > - map->name, btf_kind_str(t)); > > + map_name, btf_kind_str(t)); > > return -EINVAL; > > } > > > > - map->inner_map = calloc(1, sizeof(*map->inner_map)); > > - if (!map->inner_map) > > - return -ENOMEM; > > - map->inner_map->fd = -1; > > - map->inner_map->sec_idx = obj->efile.btf_maps_shndx; > > The refactoring didn't set map->inner_map->sec_idx. I guess since > inner_map is only used internally by libbpf, so it does not > have a user visible sec_idx and hence useless? It is worthwhile to > mention in the commit message for this difference, I think. > > > - map->inner_map->name = malloc(strlen(map->name) + > > - sizeof(".inner") + 1); > > - if (!map->inner_map->name) > > - return -ENOMEM; > > - sprintf(map->inner_map->name, "%s.inner", map->name); > > - > > - err = parse_btf_map_def(obj, map->inner_map, t, strict, > > - true /* is_inner */, NULL); > > + snprintf(inner_map_name, sizeof(inner_map_name), "%s.inner", map_name); > > + err = parse_btf_map_def(inner_map_name, btf, t, strict, inner_def, NULL); > > if (err) > > return err; > > + > > + map_def->parts |= MAP_DEF_INNER_MAP; > > } else if (strcmp(name, "pinning") == 0) { > > __u32 val; > > - int err; > > > > if (is_inner) { > > - pr_debug("map '%s': inner def can't be pinned.\n", > > - map->name); > > + pr_warn("map '%s': inner def can't be pinned.\n", map_name); > > return -EINVAL; > > } > > - if (!get_map_field_int(map->name, obj->btf, m, &val)) > > + if (!get_map_field_int(map_name, btf, m, &val)) > > return -EINVAL; > > - pr_debug("map '%s': found pinning = %u.\n", > > - map->name, val); > > - > > - if (val != LIBBPF_PIN_NONE && > > - val != LIBBPF_PIN_BY_NAME) { > > + if (val != LIBBPF_PIN_NONE && val != LIBBPF_PIN_BY_NAME) { > > pr_warn("map '%s': invalid pinning value %u.\n", > > - map->name, val); > > + map_name, val); > > return -EINVAL; > > } > > - if (val == LIBBPF_PIN_BY_NAME) { > > - err = build_map_pin_path(map, pin_root_path); > > - if (err) { > > - pr_warn("map '%s': couldn't build pin path.\n", > > - map->name); > > - return err; > > - } > > - } > > + map_def->pinning = val; > > + map_def->parts |= MAP_DEF_PINNING; > > } else { > > if (strict) { > > - pr_warn("map '%s': unknown field '%s'.\n", > > - map->name, name); > > + pr_warn("map '%s': unknown field '%s'.\n", map_name, name); > > return -ENOTSUP; > > } > > - pr_debug("map '%s': ignoring unknown field '%s'.\n", > > - map->name, name); > > + pr_debug("map '%s': ignoring unknown field '%s'.\n", map_name, name); > > } > > } > > > > - if (map->def.type == BPF_MAP_TYPE_UNSPEC) { > > - pr_warn("map '%s': map type isn't specified.\n", map->name); > > + if (map_def->map_type == BPF_MAP_TYPE_UNSPEC) { > > + pr_warn("map '%s': map type isn't specified.\n", map_name); > > return -EINVAL; > > } > > > > return 0; > > } > > > > +static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def) > > +{ > [...] > > +} > > + > > static int bpf_object__init_user_btf_map(struct bpf_object *obj, > > const struct btf_type *sec, > > int var_idx, int sec_idx, > > const Elf_Data *data, bool strict, > > const char *pin_root_path) > > { > > + struct btf_map_def map_def = {}, inner_def = {}; > > const struct btf_type *var, *def; > > const struct btf_var_secinfo *vi; > > const struct btf_var *var_extra; > > const char *map_name; > > struct bpf_map *map; > > + int err; > > > > vi = btf_var_secinfos(sec) + var_idx; > > var = btf__type_by_id(obj->btf, vi->type); > > @@ -2327,7 +2334,34 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj, > > pr_debug("map '%s': at sec_idx %d, offset %zu.\n", > > map_name, map->sec_idx, map->sec_offset); > > > > - return parse_btf_map_def(obj, map, def, strict, false, pin_root_path); > > + err = parse_btf_map_def(map->name, obj->btf, def, strict, &map_def, &inner_def); > > + if (err) > > + return err; > > + > > + fill_map_from_def(map, &map_def); > > + > > + if (map_def.pinning == LIBBPF_PIN_BY_NAME) { > > + err = build_map_pin_path(map, pin_root_path); > > + if (err) { > > + pr_warn("map '%s': couldn't build pin path.\n", map->name); > > + return err; > > + } > > + } > > + > > + if (map_def.parts & MAP_DEF_INNER_MAP) { > > + map->inner_map = calloc(1, sizeof(*map->inner_map)); > > + if (!map->inner_map) > > + return -ENOMEM; > > + map->inner_map->fd = -1; > > missing set map->inner_map->sec_idx here. I'll add it back here, but it was never really necessary. More for the completeness sake. sec_idx is used only to match relo to a map, and this inner_map is never matched and never referenced by a relocation. > > > + map->inner_map->name = malloc(strlen(map_name) + sizeof(".inner") + 1); > > + if (!map->inner_map->name) > > + return -ENOMEM; > > + sprintf(map->inner_map->name, "%s.inner", map_name); > > + > > + fill_map_from_def(map->inner_map, &inner_def); > > + } > > + > > + return 0; > > } > > > > static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict, > > diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h > > index 92b7eae10c6d..17883073710c 100644 > > --- a/tools/lib/bpf/libbpf_internal.h > > +++ b/tools/lib/bpf/libbpf_internal.h > > @@ -138,6 +138,38 @@ static inline __u32 btf_type_info(int kind, int vlen, int kflag) > > return (kflag << 31) | (kind << 24) | vlen; > > } > > > [...]
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index a0e6d6bc47f3..f6f4126389ac 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2025,255 +2025,262 @@ static int build_map_pin_path(struct bpf_map *map, const char *path) return bpf_map__set_pin_path(map, buf); } - -static int parse_btf_map_def(struct bpf_object *obj, - struct bpf_map *map, - const struct btf_type *def, - bool strict, bool is_inner, - const char *pin_root_path) +int parse_btf_map_def(const char *map_name, struct btf *btf, + const struct btf_type *def_t, bool strict, + struct btf_map_def *map_def, struct btf_map_def *inner_def) { const struct btf_type *t; const struct btf_member *m; + bool is_inner = inner_def == NULL; int vlen, i; - vlen = btf_vlen(def); - m = btf_members(def); + vlen = btf_vlen(def_t); + m = btf_members(def_t); for (i = 0; i < vlen; i++, m++) { - const char *name = btf__name_by_offset(obj->btf, m->name_off); + const char *name = btf__name_by_offset(btf, m->name_off); if (!name) { - pr_warn("map '%s': invalid field #%d.\n", map->name, i); + pr_warn("map '%s': invalid field #%d.\n", map_name, i); return -EINVAL; } if (strcmp(name, "type") == 0) { - if (!get_map_field_int(map->name, obj->btf, m, - &map->def.type)) + if (!get_map_field_int(map_name, btf, m, &map_def->map_type)) return -EINVAL; - pr_debug("map '%s': found type = %u.\n", - map->name, map->def.type); + map_def->parts |= MAP_DEF_MAP_TYPE; } else if (strcmp(name, "max_entries") == 0) { - if (!get_map_field_int(map->name, obj->btf, m, - &map->def.max_entries)) + if (!get_map_field_int(map_name, btf, m, &map_def->max_entries)) return -EINVAL; - pr_debug("map '%s': found max_entries = %u.\n", - map->name, map->def.max_entries); + map_def->parts |= MAP_DEF_MAX_ENTRIES; } else if (strcmp(name, "map_flags") == 0) { - if (!get_map_field_int(map->name, obj->btf, m, - &map->def.map_flags)) + if (!get_map_field_int(map_name, btf, m, &map_def->map_flags)) return -EINVAL; - pr_debug("map '%s': found map_flags = %u.\n", - map->name, map->def.map_flags); + map_def->parts |= MAP_DEF_MAP_FLAGS; } else if (strcmp(name, "numa_node") == 0) { - if (!get_map_field_int(map->name, obj->btf, m, &map->numa_node)) + if (!get_map_field_int(map_name, btf, m, &map_def->numa_node)) return -EINVAL; - pr_debug("map '%s': found numa_node = %u.\n", map->name, map->numa_node); + map_def->parts |= MAP_DEF_NUMA_NODE; } else if (strcmp(name, "key_size") == 0) { __u32 sz; - if (!get_map_field_int(map->name, obj->btf, m, &sz)) + if (!get_map_field_int(map_name, btf, m, &sz)) return -EINVAL; - pr_debug("map '%s': found key_size = %u.\n", - map->name, sz); - if (map->def.key_size && map->def.key_size != sz) { + if (map_def->key_size && map_def->key_size != sz) { pr_warn("map '%s': conflicting key size %u != %u.\n", - map->name, map->def.key_size, sz); + map_name, map_def->key_size, sz); return -EINVAL; } - map->def.key_size = sz; + map_def->key_size = sz; + map_def->parts |= MAP_DEF_KEY_SIZE; } else if (strcmp(name, "key") == 0) { __s64 sz; - t = btf__type_by_id(obj->btf, m->type); + t = btf__type_by_id(btf, m->type); if (!t) { pr_warn("map '%s': key type [%d] not found.\n", - map->name, m->type); + map_name, m->type); return -EINVAL; } if (!btf_is_ptr(t)) { pr_warn("map '%s': key spec is not PTR: %s.\n", - map->name, btf_kind_str(t)); + map_name, btf_kind_str(t)); return -EINVAL; } - sz = btf__resolve_size(obj->btf, t->type); + sz = btf__resolve_size(btf, t->type); if (sz < 0) { pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n", - map->name, t->type, (ssize_t)sz); + map_name, t->type, (ssize_t)sz); return sz; } - pr_debug("map '%s': found key [%u], sz = %zd.\n", - map->name, t->type, (ssize_t)sz); - if (map->def.key_size && map->def.key_size != sz) { + if (map_def->key_size && map_def->key_size != sz) { pr_warn("map '%s': conflicting key size %u != %zd.\n", - map->name, map->def.key_size, (ssize_t)sz); + map_name, map_def->key_size, (ssize_t)sz); return -EINVAL; } - map->def.key_size = sz; - map->btf_key_type_id = t->type; + map_def->key_size = sz; + map_def->key_type_id = t->type; + map_def->parts |= MAP_DEF_KEY_SIZE | MAP_DEF_KEY_TYPE; } else if (strcmp(name, "value_size") == 0) { __u32 sz; - if (!get_map_field_int(map->name, obj->btf, m, &sz)) + if (!get_map_field_int(map_name, btf, m, &sz)) return -EINVAL; - pr_debug("map '%s': found value_size = %u.\n", - map->name, sz); - if (map->def.value_size && map->def.value_size != sz) { + if (map_def->value_size && map_def->value_size != sz) { pr_warn("map '%s': conflicting value size %u != %u.\n", - map->name, map->def.value_size, sz); + map_name, map_def->value_size, sz); return -EINVAL; } - map->def.value_size = sz; + map_def->value_size = sz; + map_def->parts |= MAP_DEF_VALUE_SIZE; } else if (strcmp(name, "value") == 0) { __s64 sz; - t = btf__type_by_id(obj->btf, m->type); + t = btf__type_by_id(btf, m->type); if (!t) { pr_warn("map '%s': value type [%d] not found.\n", - map->name, m->type); + map_name, m->type); return -EINVAL; } if (!btf_is_ptr(t)) { pr_warn("map '%s': value spec is not PTR: %s.\n", - map->name, btf_kind_str(t)); + map_name, btf_kind_str(t)); return -EINVAL; } - sz = btf__resolve_size(obj->btf, t->type); + sz = btf__resolve_size(btf, t->type); if (sz < 0) { pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n", - map->name, t->type, (ssize_t)sz); + map_name, t->type, (ssize_t)sz); return sz; } - pr_debug("map '%s': found value [%u], sz = %zd.\n", - map->name, t->type, (ssize_t)sz); - if (map->def.value_size && map->def.value_size != sz) { + if (map_def->value_size && map_def->value_size != sz) { pr_warn("map '%s': conflicting value size %u != %zd.\n", - map->name, map->def.value_size, (ssize_t)sz); + map_name, map_def->value_size, (ssize_t)sz); return -EINVAL; } - map->def.value_size = sz; - map->btf_value_type_id = t->type; + map_def->value_size = sz; + map_def->value_type_id = t->type; + map_def->parts |= MAP_DEF_VALUE_SIZE | MAP_DEF_VALUE_TYPE; } else if (strcmp(name, "values") == 0) { + char inner_map_name[128]; int err; if (is_inner) { pr_warn("map '%s': multi-level inner maps not supported.\n", - map->name); + map_name); return -ENOTSUP; } if (i != vlen - 1) { pr_warn("map '%s': '%s' member should be last.\n", - map->name, name); + map_name, name); return -EINVAL; } - if (!bpf_map_type__is_map_in_map(map->def.type)) { + if (!bpf_map_type__is_map_in_map(map_def->map_type)) { pr_warn("map '%s': should be map-in-map.\n", - map->name); + map_name); return -ENOTSUP; } - if (map->def.value_size && map->def.value_size != 4) { + if (map_def->value_size && map_def->value_size != 4) { pr_warn("map '%s': conflicting value size %u != 4.\n", - map->name, map->def.value_size); + map_name, map_def->value_size); return -EINVAL; } - map->def.value_size = 4; - t = btf__type_by_id(obj->btf, m->type); + map_def->value_size = 4; + t = btf__type_by_id(btf, m->type); if (!t) { pr_warn("map '%s': map-in-map inner type [%d] not found.\n", - map->name, m->type); + map_name, m->type); return -EINVAL; } if (!btf_is_array(t) || btf_array(t)->nelems) { pr_warn("map '%s': map-in-map inner spec is not a zero-sized array.\n", - map->name); + map_name); return -EINVAL; } - t = skip_mods_and_typedefs(obj->btf, btf_array(t)->type, - NULL); + t = skip_mods_and_typedefs(btf, btf_array(t)->type, NULL); if (!btf_is_ptr(t)) { pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", - map->name, btf_kind_str(t)); + map_name, btf_kind_str(t)); return -EINVAL; } - t = skip_mods_and_typedefs(obj->btf, t->type, NULL); + t = skip_mods_and_typedefs(btf, t->type, NULL); if (!btf_is_struct(t)) { pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", - map->name, btf_kind_str(t)); + map_name, btf_kind_str(t)); return -EINVAL; } - map->inner_map = calloc(1, sizeof(*map->inner_map)); - if (!map->inner_map) - return -ENOMEM; - map->inner_map->fd = -1; - map->inner_map->sec_idx = obj->efile.btf_maps_shndx; - map->inner_map->name = malloc(strlen(map->name) + - sizeof(".inner") + 1); - if (!map->inner_map->name) - return -ENOMEM; - sprintf(map->inner_map->name, "%s.inner", map->name); - - err = parse_btf_map_def(obj, map->inner_map, t, strict, - true /* is_inner */, NULL); + snprintf(inner_map_name, sizeof(inner_map_name), "%s.inner", map_name); + err = parse_btf_map_def(inner_map_name, btf, t, strict, inner_def, NULL); if (err) return err; + + map_def->parts |= MAP_DEF_INNER_MAP; } else if (strcmp(name, "pinning") == 0) { __u32 val; - int err; if (is_inner) { - pr_debug("map '%s': inner def can't be pinned.\n", - map->name); + pr_warn("map '%s': inner def can't be pinned.\n", map_name); return -EINVAL; } - if (!get_map_field_int(map->name, obj->btf, m, &val)) + if (!get_map_field_int(map_name, btf, m, &val)) return -EINVAL; - pr_debug("map '%s': found pinning = %u.\n", - map->name, val); - - if (val != LIBBPF_PIN_NONE && - val != LIBBPF_PIN_BY_NAME) { + if (val != LIBBPF_PIN_NONE && val != LIBBPF_PIN_BY_NAME) { pr_warn("map '%s': invalid pinning value %u.\n", - map->name, val); + map_name, val); return -EINVAL; } - if (val == LIBBPF_PIN_BY_NAME) { - err = build_map_pin_path(map, pin_root_path); - if (err) { - pr_warn("map '%s': couldn't build pin path.\n", - map->name); - return err; - } - } + map_def->pinning = val; + map_def->parts |= MAP_DEF_PINNING; } else { if (strict) { - pr_warn("map '%s': unknown field '%s'.\n", - map->name, name); + pr_warn("map '%s': unknown field '%s'.\n", map_name, name); return -ENOTSUP; } - pr_debug("map '%s': ignoring unknown field '%s'.\n", - map->name, name); + pr_debug("map '%s': ignoring unknown field '%s'.\n", map_name, name); } } - if (map->def.type == BPF_MAP_TYPE_UNSPEC) { - pr_warn("map '%s': map type isn't specified.\n", map->name); + if (map_def->map_type == BPF_MAP_TYPE_UNSPEC) { + pr_warn("map '%s': map type isn't specified.\n", map_name); return -EINVAL; } return 0; } +static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def) +{ + map->def.type = def->map_type; + map->def.key_size = def->key_size; + map->def.value_size = def->value_size; + map->def.max_entries = def->max_entries; + map->def.map_flags = def->map_flags; + + map->numa_node = def->numa_node; + map->btf_key_type_id = def->key_type_id; + map->btf_value_type_id = def->value_type_id; + + if (def->parts & MAP_DEF_MAP_TYPE) + pr_debug("map '%s': found type = %u.\n", map->name, def->map_type); + + if (def->parts & MAP_DEF_KEY_TYPE) + pr_debug("map '%s': found key [%u], sz = %u.\n", + map->name, def->key_type_id, def->key_size); + else if (def->parts & MAP_DEF_KEY_SIZE) + pr_debug("map '%s': found key_size = %u.\n", map->name, def->key_size); + + if (def->parts & MAP_DEF_VALUE_TYPE) + pr_debug("map '%s': found value [%u], sz = %u.\n", + map->name, def->value_type_id, def->value_size); + else if (def->parts & MAP_DEF_VALUE_SIZE) + pr_debug("map '%s': found value_size = %u.\n", map->name, def->value_size); + + if (def->parts & MAP_DEF_MAX_ENTRIES) + pr_debug("map '%s': found max_entries = %u.\n", map->name, def->max_entries); + if (def->parts & MAP_DEF_MAP_FLAGS) + pr_debug("map '%s': found map_flags = %u.\n", map->name, def->map_flags); + if (def->parts & MAP_DEF_PINNING) + pr_debug("map '%s': found pinning = %u.\n", map->name, def->pinning); + if (def->parts & MAP_DEF_NUMA_NODE) + pr_debug("map '%s': found numa_node = %u.\n", map->name, def->numa_node); + + if (def->parts & MAP_DEF_INNER_MAP) + pr_debug("map '%s': found inner map definition.\n", map->name); +} + static int bpf_object__init_user_btf_map(struct bpf_object *obj, const struct btf_type *sec, int var_idx, int sec_idx, const Elf_Data *data, bool strict, const char *pin_root_path) { + struct btf_map_def map_def = {}, inner_def = {}; const struct btf_type *var, *def; const struct btf_var_secinfo *vi; const struct btf_var *var_extra; const char *map_name; struct bpf_map *map; + int err; vi = btf_var_secinfos(sec) + var_idx; var = btf__type_by_id(obj->btf, vi->type); @@ -2327,7 +2334,34 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj, pr_debug("map '%s': at sec_idx %d, offset %zu.\n", map_name, map->sec_idx, map->sec_offset); - return parse_btf_map_def(obj, map, def, strict, false, pin_root_path); + err = parse_btf_map_def(map->name, obj->btf, def, strict, &map_def, &inner_def); + if (err) + return err; + + fill_map_from_def(map, &map_def); + + if (map_def.pinning == LIBBPF_PIN_BY_NAME) { + err = build_map_pin_path(map, pin_root_path); + if (err) { + pr_warn("map '%s': couldn't build pin path.\n", map->name); + return err; + } + } + + if (map_def.parts & MAP_DEF_INNER_MAP) { + map->inner_map = calloc(1, sizeof(*map->inner_map)); + if (!map->inner_map) + return -ENOMEM; + map->inner_map->fd = -1; + map->inner_map->name = malloc(strlen(map_name) + sizeof(".inner") + 1); + if (!map->inner_map->name) + return -ENOMEM; + sprintf(map->inner_map->name, "%s.inner", map_name); + + fill_map_from_def(map->inner_map, &inner_def); + } + + return 0; } static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict, diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 92b7eae10c6d..17883073710c 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -138,6 +138,38 @@ static inline __u32 btf_type_info(int kind, int vlen, int kflag) return (kflag << 31) | (kind << 24) | vlen; } +enum map_def_parts { + MAP_DEF_MAP_TYPE = 0x001, + MAP_DEF_KEY_TYPE = 0x002, + MAP_DEF_KEY_SIZE = 0x004, + MAP_DEF_VALUE_TYPE = 0x008, + MAP_DEF_VALUE_SIZE = 0x010, + MAP_DEF_MAX_ENTRIES = 0x020, + MAP_DEF_MAP_FLAGS = 0x040, + MAP_DEF_NUMA_NODE = 0x080, + MAP_DEF_PINNING = 0x100, + MAP_DEF_INNER_MAP = 0x200, + + MAP_DEF_ALL = 0x3ff, /* combination of all above */ +}; + +struct btf_map_def { + enum map_def_parts parts; + __u32 map_type; + __u32 key_type_id; + __u32 key_size; + __u32 value_type_id; + __u32 value_size; + __u32 max_entries; + __u32 map_flags; + __u32 numa_node; + __u32 pinning; +}; + +int parse_btf_map_def(const char *map_name, struct btf *btf, + const struct btf_type *def_t, bool strict, + struct btf_map_def *map_def, struct btf_map_def *inner_def); + void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t cur_cnt, size_t max_cnt, size_t add_cnt); int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt);
Refactor BTF-defined maps parsing logic to allow it to be nicely reused by BPF static linker. Further, at least for BPF static linker, it's important to know which attributes of a BPF map were defined explicitly, so provide a bit set for each known portion of BTF map definition. This allows BPF static linker to do a simple check when dealing with extern map declarations. The same capabilities allow to distinguish attributes explicitly set to zero (e.g., __uint(max_entries, 0)) vs the case of not specifying it at all (no max_entries attribute at all). Libbpf is currently not utilizing that, but it could be useful for backwards compatibility reasons later. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> --- tools/lib/bpf/libbpf.c | 256 ++++++++++++++++++-------------- tools/lib/bpf/libbpf_internal.h | 32 ++++ 2 files changed, 177 insertions(+), 111 deletions(-)