diff options
| -rw-r--r-- | tools/lib/bpf/btf.c | 796 | ||||
| -rw-r--r-- | tools/lib/bpf/btf.h | 39 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.map | 20 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/btf_write.c | 278 |
4 files changed, 1128 insertions, 5 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 54861a5ba9d9..c25f49fad5a6 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -31,10 +31,10 @@ struct btf { __u32 raw_size; /* - * When BTF is loaded from ELF or raw memory it is stored - * in contiguous memory block, pointed to by raw_data pointer, and - * hdr, types_data, and strs_data point inside that memory region to - * respective parts of BTF representation: + * When BTF is loaded from an ELF or raw memory it is stored + * in a contiguous memory block. The hdr, type_data, and, strs_data + * point inside that memory region to their respective parts of BTF + * representation: * * +--------------------------------+ * | Header | Types | Strings | @@ -1025,7 +1025,7 @@ const void *btf__get_raw_data(const struct btf *btf_ro, __u32 *size) return btf->raw_data; } -const char *btf__name_by_offset(const struct btf *btf, __u32 offset) +const char *btf__str_by_offset(const struct btf *btf, __u32 offset) { if (offset < btf->hdr->str_len) return btf->strs_data + offset; @@ -1033,6 +1033,11 @@ const char *btf__name_by_offset(const struct btf *btf, __u32 offset) return NULL; } +const char *btf__name_by_offset(const struct btf *btf, __u32 offset) +{ + return btf__str_by_offset(btf, offset); +} + int btf__get_from_id(__u32 id, struct btf **btf) { struct bpf_btf_info btf_info = { 0 }; @@ -1343,6 +1348,787 @@ int btf__add_str(struct btf *btf, const char *s) return new_off; } +static void *btf_add_type_mem(struct btf *btf, size_t add_sz) +{ + return btf_add_mem(&btf->types_data, &btf->types_data_cap, 1, + btf->hdr->type_len, UINT_MAX, add_sz); +} + +static __u32 btf_type_info(int kind, int vlen, int kflag) +{ + return (kflag << 31) | (kind << 24) | vlen; +} + +static void btf_type_inc_vlen(struct btf_type *t) +{ + t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, btf_kflag(t)); +} + +/* + * Append new BTF_KIND_INT type with: + * - *name* - non-empty, non-NULL type name; + * - *sz* - power-of-2 (1, 2, 4, ..) size of the type, in bytes; + * - encoding is a combination of BTF_INT_SIGNED, BTF_INT_CHAR, BTF_INT_BOOL. + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding) +{ + struct btf_type *t; + int sz, err, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + /* byte_sz must be power of 2 */ + if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 16) + return -EINVAL; + if (encoding & ~(BTF_INT_SIGNED | BTF_INT_CHAR | BTF_INT_BOOL)) + return -EINVAL; + + /* deconstruct BTF, if necessary, and invalidate raw_data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type) + sizeof(int); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + /* if something goes wrong later, we might end up with an extra string, + * but that shouldn't be a problem, because BTF can't be constructed + * completely anyway and will most probably be just discarded + */ + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_INT, 0, 0); + t->size = byte_sz; + /* set INT info, we don't allow setting legacy bit offset/size */ + *(__u32 *)(t + 1) = (encoding << 24) | (byte_sz * 8); + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* it's completely legal to append BTF types with type IDs pointing forward to + * types that haven't been appended yet, so we only make sure that id looks + * sane, we can't guarantee that ID will always be valid + */ +static int validate_type_id(int id) +{ + if (id < 0 || id > BTF_MAX_NR_TYPES) + return -EINVAL; + return 0; +} + +/* generic append function for PTR, TYPEDEF, CONST/VOLATILE/RESTRICT */ +static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref_type_id) +{ + struct btf_type *t; + int sz, name_off = 0, err; + + if (validate_type_id(ref_type_id)) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + t->name_off = name_off; + t->info = btf_type_info(kind, 0, 0); + t->type = ref_type_id; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new BTF_KIND_PTR type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_ptr(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_PTR, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_ARRAY type with: + * - *index_type_id* - type ID of the type describing array index; + * - *elem_type_id* - type ID of the type describing array element; + * - *nr_elems* - the size of the array; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_array(struct btf *btf, int index_type_id, int elem_type_id, __u32 nr_elems) +{ + struct btf_type *t; + struct btf_array *a; + int sz, err; + + if (validate_type_id(index_type_id) || validate_type_id(elem_type_id)) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type) + sizeof(struct btf_array); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + t->name_off = 0; + t->info = btf_type_info(BTF_KIND_ARRAY, 0, 0); + t->size = 0; + + a = btf_array(t); + a->type = elem_type_id; + a->index_type = index_type_id; + a->nelems = nr_elems; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* generic STRUCT/UNION append function */ +static int btf_add_composite(struct btf *btf, int kind, const char *name, __u32 bytes_sz) +{ + struct btf_type *t; + int sz, err, name_off = 0; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + /* start out with vlen=0 and no kflag; this will be adjusted when + * adding each member + */ + t->name_off = name_off; + t->info = btf_type_info(kind, 0, 0); + t->size = bytes_sz; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new BTF_KIND_STRUCT type with: + * - *name* - name of the struct, can be NULL or empty for anonymous structs; + * - *byte_sz* - size of the struct, in bytes; + * + * Struct initially has no fields in it. Fields can be added by + * btf__add_field() right after btf__add_struct() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_struct(struct btf *btf, const char *name, __u32 byte_sz) +{ + return btf_add_composite(btf, BTF_KIND_STRUCT, name, byte_sz); +} + +/* + * Append new BTF_KIND_UNION type with: + * - *name* - name of the union, can be NULL or empty for anonymous union; + * - *byte_sz* - size of the union, in bytes; + * + * Union initially has no fields in it. Fields can be added by + * btf__add_field() right after btf__add_union() succeeds. All fields + * should have *bit_offset* of 0. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_union(struct btf *btf, const char *name, __u32 byte_sz) +{ + return btf_add_composite(btf, BTF_KIND_UNION, name, byte_sz); +} + +/* + * Append new field for the current STRUCT/UNION type with: + * - *name* - name of the field, can be NULL or empty for anonymous field; + * - *type_id* - type ID for the type describing field type; + * - *bit_offset* - bit offset of the start of the field within struct/union; + * - *bit_size* - bit size of a bitfield, 0 for non-bitfield fields; + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_field(struct btf *btf, const char *name, int type_id, + __u32 bit_offset, __u32 bit_size) +{ + struct btf_type *t; + struct btf_member *m; + bool is_bitfield; + int sz, name_off = 0; + + /* last type should be union/struct */ + if (btf->nr_types == 0) + return -EINVAL; + t = btf_type_by_id(btf, btf->nr_types); + if (!btf_is_composite(t)) + return -EINVAL; + + if (validate_type_id(type_id)) + return -EINVAL; + /* best-effort bit field offset/size enforcement */ + is_bitfield = bit_size || (bit_offset % 8 != 0); + if (is_bitfield && (bit_size == 0 || bit_size > 255 || bit_offset > 0xffffff)) + return -EINVAL; + + /* only offset 0 is allowed for unions */ + if (btf_is_union(t) && bit_offset) + return -EINVAL; + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_member); + m = btf_add_type_mem(btf, sz); + if (!m) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + m->name_off = name_off; + m->type = type_id; + m->offset = bit_offset | (bit_size << 24); + + /* btf_add_type_mem can invalidate t pointer */ + t = btf_type_by_id(btf, btf->nr_types); + /* update parent type's vlen and kflag */ + t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, is_bitfield || btf_kflag(t)); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_ENUM type with: + * - *name* - name of the enum, can be NULL or empty for anonymous enums; + * - *byte_sz* - size of the enum, in bytes. + * + * Enum initially has no enum values in it (and corresponds to enum forward + * declaration). Enumerator values can be added by btf__add_enum_value() + * immediately after btf__add_enum() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_enum(struct btf *btf, const char *name, __u32 byte_sz) +{ + struct btf_type *t; + int sz, err, name_off = 0; + + /* byte_sz must be power of 2 */ + if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 8) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + /* start out with vlen=0; it will be adjusted when adding enum values */ + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_ENUM, 0, 0); + t->size = byte_sz; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new enum value for the current ENUM type with: + * - *name* - name of the enumerator value, can't be NULL or empty; + * - *value* - integer value corresponding to enum value *name*; + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_enum_value(struct btf *btf, const char *name, __s64 value) +{ + struct btf_type *t; + struct btf_enum *v; + int sz, name_off; + + /* last type should be BTF_KIND_ENUM */ + if (btf->nr_types == 0) + return -EINVAL; + t = btf_type_by_id(btf, btf->nr_types); + if (!btf_is_enum(t)) + return -EINVAL; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + if (value < INT_MIN || value > UINT_MAX) + return -E2BIG; + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_enum); + v = btf_add_type_mem(btf, sz); + if (!v) + return -ENOMEM; + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + v->name_off = name_off; + v->val = value; + + /* update parent type's vlen */ + t = btf_type_by_id(btf, btf->nr_types); + btf_type_inc_vlen(t); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_FWD type with: + * - *name*, non-empty/non-NULL name; + * - *fwd_kind*, kind of forward declaration, one of BTF_FWD_STRUCT, + * BTF_FWD_UNION, or BTF_FWD_ENUM; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind) +{ + if (!name || !name[0]) + return -EINVAL; + + switch (fwd_kind) { + case BTF_FWD_STRUCT: + case BTF_FWD_UNION: { + struct btf_type *t; + int id; + + id = btf_add_ref_kind(btf, BTF_KIND_FWD, name, 0); + if (id <= 0) + return id; + t = btf_type_by_id(btf, id); + t->info = btf_type_info(BTF_KIND_FWD, 0, fwd_kind == BTF_FWD_UNION); + return id; + } + case BTF_FWD_ENUM: + /* enum forward in BTF currently is just an enum with no enum + * values; we also assume a standard 4-byte size for it + */ + return btf__add_enum(btf, name, sizeof(int)); + default: + return -EINVAL; + } +} + +/* + * Append new BTF_KING_TYPEDEF type with: + * - *name*, non-empty/non-NULL name; + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id) +{ + if (!name || !name[0]) + return -EINVAL; + + return btf_add_ref_kind(btf, BTF_KIND_TYPEDEF, name, ref_type_id); +} + +/* + * Append new BTF_KIND_VOLATILE type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_volatile(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_VOLATILE, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_CONST type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_const(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_CONST, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_RESTRICT type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_restrict(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_RESTRICT, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_FUNC type with: + * - *name*, non-empty/non-NULL name; + * - *proto_type_id* - FUNC_PROTO's type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_func(struct btf *btf, const char *name, + enum btf_func_linkage linkage, int proto_type_id) +{ + int id; + + if (!name || !name[0]) + return -EINVAL; + if (linkage != BTF_FUNC_STATIC && linkage != BTF_FUNC_GLOBAL && + linkage != BTF_FUNC_EXTERN) + return -EINVAL; + + id = btf_add_ref_kind(btf, BTF_KIND_FUNC, name, proto_type_id); + if (id > 0) { + struct btf_type *t = btf_type_by_id(btf, id); + + t->info = btf_type_info(BTF_KIND_FUNC, linkage, 0); + } + return id; +} + +/* + * Append new BTF_KIND_FUNC_PROTO with: + * - *ret_type_id* - type ID for return result of a function. + * + * Function prototype initially has no arguments, but they can be added by + * btf__add_func_param() one by one, immediately after + * btf__add_func_proto() succeeded. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_func_proto(struct btf *btf, int ret_type_id) +{ + struct btf_type *t; + int sz, err; + + if (validate_type_id(ret_type_id)) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + /* start out with vlen=0; this will be adjusted when adding enum + * values, if necessary + */ + t->name_off = 0; + t->info = btf_type_info(BTF_KIND_FUNC_PROTO, 0, 0); + t->type = ret_type_id; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new function parameter for current FUNC_PROTO type with: + * - *name* - parameter name, can be NULL or empty; + * - *type_id* - type ID describing the type of the parameter. + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_func_param(struct btf *btf, const char *name, int type_id) +{ + struct btf_type *t; + struct btf_param *p; + int sz, name_off = 0; + + if (validate_type_id(type_id)) + return -EINVAL; + + /* last type should be BTF_KIND_FUNC_PROTO */ + if (btf->nr_types == 0) + return -EINVAL; + t = btf_type_by_id(btf, btf->nr_types); + if (!btf_is_func_proto(t)) + return -EINVAL; + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_param); + p = btf_add_type_mem(btf, sz); + if (!p) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + p->name_off = name_off; + p->type = type_id; + + /* update parent type's vlen */ + t = btf_type_by_id(btf, btf->nr_types); + btf_type_inc_vlen(t); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_VAR type with: + * - *name* - non-empty/non-NULL name; + * - *linkage* - variable linkage, one of BTF_VAR_STATIC, + * BTF_VAR_GLOBAL_ALLOCATED, or BTF_VAR_GLOBAL_EXTERN; + * - *type_id* - type ID of the type describing the type of the variable. + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id) +{ + struct btf_type *t; + struct btf_var *v; + int sz, err, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + if (linkage != BTF_VAR_STATIC && linkage != BTF_VAR_GLOBAL_ALLOCATED && + linkage != BTF_VAR_GLOBAL_EXTERN) + return -EINVAL; + if (validate_type_id(type_id)) + return -EINVAL; + + /* deconstruct BTF, if necessary, and invalidate raw_data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type) + sizeof(struct btf_var); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_VAR, 0, 0); + t->type = type_id; + + v = btf_var(t); + v->linkage = linkage; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new BTF_KIND_DATASEC type with: + * - *name* - non-empty/non-NULL name; + * - *byte_sz* - data section size, in bytes. + * + * Data section is initially empty. Variables info can be added with + * btf__add_datasec_var_info() calls, after btf__add_datasec() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz) +{ + struct btf_type *t; + int sz, err, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + /* start with vlen=0, which will be update as var_secinfos are added */ + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_DATASEC, 0, 0); + t->size = byte_sz; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new data section variable information entry for current DATASEC type: + * - *var_type_id* - type ID, describing type of the variable; + * - *offset* - variable offset within data section, in bytes; + * - *byte_sz* - variable size, in bytes. + * + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __u32 byte_sz) +{ + struct btf_type *t; + struct btf_var_secinfo *v; + int sz; + + /* last type should be BTF_KIND_DATASEC */ + if (btf->nr_types == 0) + return -EINVAL; + t = btf_type_by_id(btf, btf->nr_types); + if (!btf_is_datasec(t)) + return -EINVAL; + + if (validate_type_id(var_type_id)) + return -EINVAL; + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_var_secinfo); + v = btf_add_type_mem(btf, sz); + if (!v) + return -ENOMEM; + + v->type = var_type_id; + v->offset = offset; + v->size = byte_sz; + + /* update parent type's vlen */ + t = btf_type_by_id(btf, btf->nr_types); + btf_type_inc_vlen(t); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + struct btf_ext_sec_setup_param { __u32 off; __u32 len; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index b387d0b61f1c..f7dec0144c3c 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -49,6 +49,7 @@ LIBBPF_API int btf__fd(const struct btf *btf); LIBBPF_API void btf__set_fd(struct btf *btf, int fd); LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size); LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset); +LIBBPF_API const char *btf__str_by_offset(const struct btf *btf, __u32 offset); LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf); LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, __u32 expected_key_size, @@ -77,6 +78,44 @@ LIBBPF_API struct btf *libbpf_find_kernel_btf(void); LIBBPF_API int btf__find_str(struct btf *btf, const char *s); LIBBPF_API int btf__add_str(struct btf *btf, const char *s); +LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding); +LIBBPF_API int btf__add_ptr(struct btf *btf, int ref_type_id); +LIBBPF_API int btf__add_array(struct btf *btf, + int index_type_id, int elem_type_id, __u32 nr_elems); +/* struct/union construction APIs */ +LIBBPF_API int btf__add_struct(struct btf *btf, const char *name, __u32 sz); +LIBBPF_API int btf__add_union(struct btf *btf, const char *name, __u32 sz); +LIBBPF_API int btf__add_field(struct btf *btf, const char *name, int field_type_id, + __u32 bit_offset, __u32 bit_size); + +/* enum construction APIs */ +LIBBPF_API int btf__add_enum(struct btf *btf, const char *name, __u32 bytes_sz); +LIBBPF_API int btf__add_enum_value(struct btf *btf, const char *name, __s64 value); + +enum btf_fwd_kind { + BTF_FWD_STRUCT = 0, + BTF_FWD_UNION = 1, + BTF_FWD_ENUM = 2, +}; + +LIBBPF_API int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind); +LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id); +LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id); +LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id); +LIBBPF_API int btf__add_restrict(struct btf *btf, int ref_type_id); + +/* func and func_proto construction APIs */ +LIBBPF_API int btf__add_func(struct btf *btf, const char *name, + enum btf_func_linkage linkage, int proto_type_id); +LIBBPF_API int btf__add_func_proto(struct btf *btf, int ret_type_id); +LIBBPF_API int btf__add_func_param(struct btf *btf, const char *name, int type_id); + +/* var & datasec construction APIs */ +LIBBPF_API int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id); +LIBBPF_API int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz); +LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id, + __u32 offset, __u32 byte_sz); + struct btf_dedup_opts { unsigned int dedup_table_size; bool dont_resolve_fwds; diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index d02d8f51e34f..6b10ebad69c6 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -305,9 +305,29 @@ LIBBPF_0.2.0 { bpf_prog_bind_map; bpf_prog_test_run_opts; bpf_program__section_name; + btf__add_array; + btf__add_const; + btf__add_enum; + btf__add_enum_value; + btf__add_datasec; + btf__add_datasec_var_info; + btf__add_field; + btf__add_func; + btf__add_func_param; + btf__add_func_proto; + btf__add_fwd; + btf__add_int; + btf__add_ptr; + btf__add_restrict; btf__add_str; + btf__add_struct; + btf__add_typedef; + btf__add_union; + btf__add_var; + btf__add_volatile; btf__find_str; btf__new_empty; + btf__str_by_offset; perf_buffer__buffer_cnt; perf_buffer__buffer_fd; perf_buffer__epoll_fd; diff --git a/tools/testing/selftests/bpf/prog_tests/btf_write.c b/tools/testing/selftests/bpf/prog_tests/btf_write.c new file mode 100644 index 000000000000..88dce2cfa79b --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/btf_write.c @@ -0,0 +1,278 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020 Facebook */ +#include <test_progs.h> +#include <bpf/btf.h> + +#define ASSERT_EQ(actual, expected, name) ({ \ + typeof(actual) ___act = (actual); \ + typeof(expected) ___exp = (expected); \ + bool ___ok = ___act == ___exp; \ + CHECK(!___ok, (name), \ + "unexpected %s: actual %lld != expected %lld\n", \ + (name), (long long)(___act), (long long)(___exp)); \ + ___ok; \ +}) + +#define ASSERT_STREQ(actual, expected, name) ({ \ + const char *___act = actual; \ + const char *___exp = expected; \ + bool ___ok = strcmp(___act, ___exp) == 0; \ + CHECK(!___ok, (name), \ + "unexpected %s: actual '%s' != expected '%s'\n", \ + (name), ___act, ___exp); \ + ___ok; \ +}) + +#define ASSERT_OK(res, name) ({ \ + long long ___res = (res); \ + bool ___ok = ___res == 0; \ + CHECK(!___ok, (name), "unexpected error: %lld\n", ___res); \ + ___ok; \ +}) + +#define ASSERT_ERR(res, name) ({ \ + long long ___res = (res); \ + bool ___ok = ___res < 0; \ + CHECK(!___ok, (name), "unexpected success: %lld\n", ___res); \ + ___ok; \ +}) + +static int duration = 0; + +void test_btf_write() { + const struct btf_var_secinfo *vi; + const struct btf_type *t; + const struct btf_member *m; + const struct btf_enum *v; + const struct btf_param *p; + struct btf *btf; + int id, err, str_off; + + btf = btf__new_empty(); + if (CHECK(IS_ERR(btf), "new_empty", "failed: %ld\n", PTR_ERR(btf))) + return; + + str_off = btf__find_str(btf, "int"); + ASSERT_EQ(str_off, -ENOENT, "int_str_missing_off"); + + str_off = btf__add_str(btf, "int"); + ASSERT_EQ(str_off, 1, "int_str_off"); + + str_off = btf__find_str(btf, "int"); + ASSERT_EQ(str_off, 1, "int_str_found_off"); + + /* BTF_KIND_INT */ + id = btf__add_int(btf, "int", 4, BTF_INT_SIGNED); + ASSERT_EQ(id, 1, "int_id"); + + t = btf__type_by_id(btf, 1); + /* should re-use previously added "int" string */ + ASSERT_EQ(t->name_off, str_off, "int_name_off"); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "int", "int_name"); + ASSERT_EQ(btf_kind(t), BTF_KIND_INT, "int_kind"); + ASSERT_EQ(t->size, 4, "int_sz"); + ASSERT_EQ(btf_int_encoding(t), BTF_INT_SIGNED, "int_enc"); + ASSERT_EQ(btf_int_bits(t), 32, "int_bits"); + + /* invalid int size */ + id = btf__add_int(btf, "bad sz int", 7, 0); + ASSERT_ERR(id, "int_bad_sz"); + /* invalid encoding */ + id = btf__add_int(btf, "bad enc int", 4, 123); + ASSERT_ERR(id, "int_bad_enc"); + /* NULL name */ + id = btf__add_int(btf, NULL, 4, 0); + ASSERT_ERR(id, "int_bad_null_name"); + /* empty name */ + id = btf__add_int(btf, "", 4, 0); + ASSERT_ERR(id, "int_bad_empty_name"); + + /* PTR/CONST/VOLATILE/RESTRICT */ + id = btf__add_ptr(btf, 1); + ASSERT_EQ(id, 2, "ptr_id"); + t = btf__type_by_id(btf, 2); + ASSERT_EQ(btf_kind(t), BTF_KIND_PTR, "ptr_kind"); + ASSERT_EQ(t->type, 1, "ptr_type"); + + id = btf__add_const(btf, 5); /* points forward to restrict */ + ASSERT_EQ(id, 3, "const_id"); + t = btf__type_by_id(btf, 3); + ASSERT_EQ(btf_kind(t), BTF_KIND_CONST, "const_kind"); + ASSERT_EQ(t->type, 5, "const_type"); + + id = btf__add_volatile(btf, 3); + ASSERT_EQ(id, 4, "volatile_id"); + t = btf__type_by_id(btf, 4); + ASSERT_EQ(btf_kind(t), BTF_KIND_VOLATILE, "volatile_kind"); + ASSERT_EQ(t->type, 3, "volatile_type"); + + id = btf__add_restrict(btf, 4); + ASSERT_EQ(id, 5, "restrict_id"); + t = btf__type_by_id(btf, 5); + ASSERT_EQ(btf_kind(t), BTF_KIND_RESTRICT, "restrict_kind"); + ASSERT_EQ(t->type, 4, "restrict_type"); + + /* ARRAY */ + id = btf__add_array(btf, 1, 2, 10); /* int *[10] */ + ASSERT_EQ(id, 6, "array_id"); + t = btf__type_by_id(btf, 6); + ASSERT_EQ(btf_kind(t), BTF_KIND_ARRAY, "array_kind"); + ASSERT_EQ(btf_array(t)->index_type, 1, "array_index_type"); + ASSERT_EQ(btf_array(t)->type, 2, "array_elem_type"); + ASSERT_EQ(btf_array(t)->nelems, 10, "array_nelems"); + + /* STRUCT */ + err = btf__add_field(btf, "field", 1, 0, 0); + ASSERT_ERR(err, "no_struct_field"); + id = btf__add_struct(btf, "s1", 8); + ASSERT_EQ(id, 7, "struct_id"); + err = btf__add_field(btf, "f1", 1, 0, 0); + ASSERT_OK(err, "f1_res"); + err = btf__add_field(btf, "f2", 1, 32, 16); + ASSERT_OK(err, "f2_res"); + + t = btf__type_by_id(btf, 7); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "s1", "struct_name"); + ASSERT_EQ(btf_kind(t), BTF_KIND_STRUCT, "struct_kind"); + ASSERT_EQ(btf_vlen(t), 2, "struct_vlen"); + ASSERT_EQ(btf_kflag(t), true, "struct_kflag"); + ASSERT_EQ(t->size, 8, "struct_sz"); + m = btf_members(t) + 0; + ASSERT_STREQ(btf__str_by_offset(btf, m->name_off), "f1", "f1_name"); + ASSERT_EQ(m->type, 1, "f1_type"); + ASSERT_EQ(btf_member_bit_offset(t, 0), 0, "f1_bit_off"); + ASSERT_EQ(btf_member_bitfield_size(t, 0), 0, "f1_bit_sz"); + m = btf_members(t) + 1; + ASSERT_STREQ(btf__str_by_offset(btf, m->name_off), "f2", "f2_name"); + ASSERT_EQ(m->type, 1, "f2_type"); + ASSERT_EQ(btf_member_bit_offset(t, 1), 32, "f2_bit_off"); + ASSERT_EQ(btf_member_bitfield_size(t, 1), 16, "f2_bit_sz"); + + /* UNION */ + id = btf__add_union(btf, "u1", 8); + ASSERT_EQ(id, 8, "union_id"); + + /* invalid, non-zero offset */ + err = btf__add_field(btf, "field", 1, 1, 0); + ASSERT_ERR(err, "no_struct_field"); + + err = btf__add_field(btf, "f1", 1, 0, 16); + ASSERT_OK(err, "f1_res"); + + t = btf__type_by_id(btf, 8); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "u1", "union_name"); + ASSERT_EQ(btf_kind(t), BTF_KIND_UNION, "union_kind"); + ASSERT_EQ(btf_vlen(t), 1, "union_vlen"); + ASSERT_EQ(btf_kflag(t), true, "union_kflag"); + ASSERT_EQ(t->size, 8, "union_sz"); + m = btf_members(t) + 0; + ASSERT_STREQ(btf__str_by_offset(btf, m->name_off), "f1", "f1_name"); + ASSERT_EQ(m->type, 1, "f1_type"); + ASSERT_EQ(btf_member_bit_offset(t, 0), 0, "f1_bit_off"); + ASSERT_EQ(btf_member_bitfield_size(t, 0), 16, "f1_bit_sz"); + + /* ENUM */ + id = btf__add_enum(btf, "e1", 4); + ASSERT_EQ(id, 9, "enum_id"); + err = btf__add_enum_value(btf, "v1", 1); + ASSERT_OK(err, "v1_res"); + err = btf__add_enum_value(btf, "v2", 2); + ASSERT_OK(err, "v2_res"); + + t = btf__type_by_id(btf, 9); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "e1", "enum_name"); + ASSERT_EQ(btf_kind(t), BTF_KIND_ENUM, "enum_kind"); + ASSERT_EQ(btf_vlen(t), 2, "enum_vlen"); + ASSERT_EQ(t->size, 4, "enum_sz"); + v = btf_enum(t) + 0; + ASSERT_STREQ(btf__str_by_offset(btf, v->name_off), "v1", "v1_name"); + ASSERT_EQ(v->val, 1, "v1_val"); + v = btf_enum(t) + 1; + ASSERT_STREQ(btf__str_by_offset(btf, v->name_off), "v2", "v2_name"); + ASSERT_EQ(v->val, 2, "v2_val"); + + /* FWDs */ + id = btf__add_fwd(btf, "struct_fwd", BTF_FWD_STRUCT); + ASSERT_EQ(id, 10, "struct_fwd_id"); + t = btf__type_by_id(btf, 10); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "struct_fwd", "fwd_name"); + ASSERT_EQ(btf_kind(t), BTF_KIND_FWD, "fwd_kind"); + ASSERT_EQ(btf_kflag(t), 0, "fwd_kflag"); + + id = btf__add_fwd(btf, "union_fwd", BTF_FWD_UNION); + ASSERT_EQ(id, 11, "union_fwd_id"); + t = btf__type_by_id(btf, 11); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "union_fwd", "fwd_name"); + ASSERT_EQ(btf_kind(t), BTF_KIND_FWD, "fwd_kind"); + ASSERT_EQ(btf_kflag(t), 1, "fwd_kflag"); + + id = btf__add_fwd(btf, "enum_fwd", BTF_FWD_ENUM); + ASSERT_EQ(id, 12, "enum_fwd_id"); + t = btf__type_by_id(btf, 12); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "enum_fwd", "fwd_name"); + ASSERT_EQ(btf_kind(t), BTF_KIND_ENUM, "enum_fwd_kind"); + ASSERT_EQ(btf_vlen(t), 0, "enum_fwd_kind"); + ASSERT_EQ(t->size, 4, "enum_fwd_sz"); + + /* TYPEDEF */ + id = btf__add_typedef(btf, "typedef1", 1); + ASSERT_EQ(id, 13, "typedef_fwd_id"); + t = btf__type_by_id(btf, 13); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "typedef1", "typedef_name"); + ASSERT_EQ(btf_kind(t), BTF_KIND_TYPEDEF, "typedef_kind"); + ASSERT_EQ(t->type, 1, "typedef_type"); + + /* FUNC & FUNC_PROTO */ + id = btf__add_func(btf, "func1", BTF_FUNC_GLOBAL, 15); + ASSERT_EQ(id, 14, "func_id"); + t = btf__type_by_id(btf, 14); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "func1", "func_name"); + ASSERT_EQ(t->type, 15, "func_type"); + ASSERT_EQ(btf_kind(t), BTF_KIND_FUNC, "func_kind"); + ASSERT_EQ(btf_vlen(t), BTF_FUNC_GLOBAL, "func_vlen"); + + id = btf__add_func_proto(btf, 1); + ASSERT_EQ(id, 15, "func_proto_id"); + err = btf__add_func_param(btf, "p1", 1); + ASSERT_OK(err, "p1_res"); + err = btf__add_func_param(btf, "p2", 2); + ASSERT_OK(err, "p2_res"); + + t = btf__type_by_id(btf, 15); + ASSERT_EQ(btf_kind(t), BTF_KIND_FUNC_PROTO, "func_proto_kind"); + ASSERT_EQ(btf_vlen(t), 2, "func_proto_vlen"); + ASSERT_EQ(t->type, 1, "func_proto_ret_type"); + p = btf_params(t) + 0; + ASSERT_STREQ(btf__str_by_offset(btf, p->name_off), "p1", "p1_name"); + ASSERT_EQ(p->type, 1, "p1_type"); + p = btf_params(t) + 1; + ASSERT_STREQ(btf__str_by_offset(btf, p->name_off), "p2", "p2_name"); + ASSERT_EQ(p->type, 2, "p2_type"); + + /* VAR */ + id = btf__add_var(btf, "var1", BTF_VAR_GLOBAL_ALLOCATED, 1); + ASSERT_EQ(id, 16, "var_id"); + t = btf__type_by_id(btf, 16); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "var1", "var_name"); + ASSERT_EQ(btf_kind(t), BTF_KIND_VAR, "var_kind"); + ASSERT_EQ(t->type, 1, "var_type"); + ASSERT_EQ(btf_var(t)->linkage, BTF_VAR_GLOBAL_ALLOCATED, "var_type"); + + /* DATASECT */ + id = btf__add_datasec(btf, "datasec1", 12); + ASSERT_EQ(id, 17, "datasec_id"); + err = btf__add_datasec_var_info(btf, 1, 4, 8); + ASSERT_OK(err, "v1_res"); + + t = btf__type_by_id(btf, 17); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "datasec1", "datasec_name"); + ASSERT_EQ(t->size, 12, "datasec_sz"); + ASSERT_EQ(btf_kind(t), BTF_KIND_DATASEC, "datasec_kind"); + ASSERT_EQ(btf_vlen(t), 1, "datasec_vlen"); + vi = btf_var_secinfos(t) + 0; + ASSERT_EQ(vi->type, 1, "v1_type"); + ASSERT_EQ(vi->offset, 4, "v1_off"); + ASSERT_EQ(vi->size, 8, "v1_sz"); + + btf__free(btf); +} |