diff options
| -rw-r--r-- | tools/lib/bpf/btf.c | 1851 | ||||
| -rw-r--r-- | tools/lib/bpf/btf.h | 10 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.map | 3 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/test_btf.c | 535 |
4 files changed, 2332 insertions, 67 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 7ec0463354db..4949f8840bda 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -182,6 +182,37 @@ static int btf_parse_str_sec(struct btf *btf) return 0; } +static int btf_type_size(struct btf_type *t) +{ + int base_size = sizeof(struct btf_type); + __u16 vlen = BTF_INFO_VLEN(t->info); + + switch (BTF_INFO_KIND(t->info)) { + case BTF_KIND_FWD: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + return base_size; + case BTF_KIND_INT: + return base_size + sizeof(__u32); + case BTF_KIND_ENUM: + return base_size + vlen * sizeof(struct btf_enum); + case BTF_KIND_ARRAY: + return base_size + sizeof(struct btf_array); + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + return base_size + vlen * sizeof(struct btf_member); + case BTF_KIND_FUNC_PROTO: + return base_size + vlen * sizeof(struct btf_param); + default: + pr_debug("Unsupported BTF_KIND:%u\n", BTF_INFO_KIND(t->info)); + return -EINVAL; + } +} + static int btf_parse_type_sec(struct btf *btf) { struct btf_header *hdr = btf->hdr; @@ -191,41 +222,13 @@ static int btf_parse_type_sec(struct btf *btf) while (next_type < end_type) { struct btf_type *t = next_type; - __u16 vlen = BTF_INFO_VLEN(t->info); + int type_size; int err; - next_type += sizeof(*t); - switch (BTF_INFO_KIND(t->info)) { - case BTF_KIND_INT: - next_type += sizeof(int); - break; - case BTF_KIND_ARRAY: - next_type += sizeof(struct btf_array); - break; - case BTF_KIND_STRUCT: - case BTF_KIND_UNION: - next_type += vlen * sizeof(struct btf_member); - break; - case BTF_KIND_ENUM: - next_type += vlen * sizeof(struct btf_enum); - break; - case BTF_KIND_FUNC_PROTO: - next_type += vlen * sizeof(struct btf_param); - break; - case BTF_KIND_FUNC: - case BTF_KIND_TYPEDEF: - case BTF_KIND_PTR: - case BTF_KIND_FWD: - case BTF_KIND_VOLATILE: - case BTF_KIND_CONST: - case BTF_KIND_RESTRICT: - break; - default: - pr_debug("Unsupported BTF_KIND:%u\n", - BTF_INFO_KIND(t->info)); - return -EINVAL; - } - + type_size = btf_type_size(t); + if (type_size < 0) + return type_size; + next_type += type_size; err = btf_add_type(btf, t); if (err) return err; @@ -234,6 +237,11 @@ static int btf_parse_type_sec(struct btf *btf) return 0; } +__u32 btf__get_nr_types(const struct btf *btf) +{ + return btf->nr_types; +} + const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id) { if (type_id > btf->nr_types) @@ -252,21 +260,6 @@ static bool btf_type_is_void_or_null(const struct btf_type *t) return !t || btf_type_is_void(t); } -static __s64 btf_type_size(const struct btf_type *t) -{ - switch (BTF_INFO_KIND(t->info)) { - case BTF_KIND_INT: - case BTF_KIND_STRUCT: - case BTF_KIND_UNION: - case BTF_KIND_ENUM: - return t->size; - case BTF_KIND_PTR: - return sizeof(void *); - default: - return -EINVAL; - } -} - #define MAX_RESOLVE_DEPTH 32 __s64 btf__resolve_size(const struct btf *btf, __u32 type_id) @@ -280,11 +273,16 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id) t = btf__type_by_id(btf, type_id); for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t); i++) { - size = btf_type_size(t); - if (size >= 0) - break; - switch (BTF_INFO_KIND(t->info)) { + case BTF_KIND_INT: + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_ENUM: + size = t->size; + goto done; + case BTF_KIND_PTR: + size = sizeof(void *); + goto done; case BTF_KIND_TYPEDEF: case BTF_KIND_VOLATILE: case BTF_KIND_CONST: @@ -308,6 +306,7 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id) if (size < 0) return -EINVAL; +done: if (nelems && size > UINT32_MAX / nelems) return -E2BIG; @@ -433,6 +432,13 @@ int btf__fd(const struct btf *btf) return btf->fd; } +void btf__get_strings(const struct btf *btf, const char **strings, + __u32 *str_len) +{ + *strings = btf->strings; + *str_len = btf->hdr->str_len; +} + const char *btf__name_by_offset(const struct btf *btf, __u32 offset) { if (offset < btf->hdr->str_len) @@ -855,3 +861,1744 @@ __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext) { return btf_ext->line_info.rec_size; } + +struct btf_dedup; + +static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, + const struct btf_dedup_opts *opts); +static void btf_dedup_free(struct btf_dedup *d); +static int btf_dedup_strings(struct btf_dedup *d); +static int btf_dedup_prim_types(struct btf_dedup *d); +static int btf_dedup_struct_types(struct btf_dedup *d); +static int btf_dedup_ref_types(struct btf_dedup *d); +static int btf_dedup_compact_types(struct btf_dedup *d); +static int btf_dedup_remap_types(struct btf_dedup *d); + +/* + * Deduplicate BTF types and strings. + * + * BTF dedup algorithm takes as an input `struct btf` representing `.BTF` ELF + * section with all BTF type descriptors and string data. It overwrites that + * memory in-place with deduplicated types and strings without any loss of + * information. If optional `struct btf_ext` representing '.BTF.ext' ELF section + * is provided, all the strings referenced from .BTF.ext section are honored + * and updated to point to the right offsets after deduplication. + * + * If function returns with error, type/string data might be garbled and should + * be discarded. + * + * More verbose and detailed description of both problem btf_dedup is solving, + * as well as solution could be found at: + * https://facebookmicrosites.github.io/bpf/blog/2018/11/14/btf-enhancement.html + * + * Problem description and justification + * ===================================== + * + * BTF type information is typically emitted either as a result of conversion + * from DWARF to BTF or directly by compiler. In both cases, each compilation + * unit contains information about a subset of all the types that are used + * in an application. These subsets are frequently overlapping and contain a lot + * of duplicated information when later concatenated together into a single + * binary. This algorithm ensures that each unique type is represented by single + * BTF type descriptor, greatly reducing resulting size of BTF data. + * + * Compilation unit isolation and subsequent duplication of data is not the only + * problem. The same type hierarchy (e.g., struct and all the type that struct + * references) in different compilation units can be represented in BTF to + * various degrees of completeness (or, rather, incompleteness) due to + * struct/union forward declarations. + * + * Let's take a look at an example, that we'll use to better understand the + * problem (and solution). Suppose we have two compilation units, each using + * same `struct S`, but each of them having incomplete type information about + * struct's fields: + * + * // CU #1: + * struct S; + * struct A { + * int a; + * struct A* self; + * struct S* parent; + * }; + * struct B; + * struct S { + * struct A* a_ptr; + * struct B* b_ptr; + * }; + * + * // CU #2: + * struct S; + * struct A; + * struct B { + * int b; + * struct B* self; + * struct S* parent; + * }; + * struct S { + * struct A* a_ptr; + * struct B* b_ptr; + * }; + * + * In case of CU #1, BTF data will know only that `struct B` exist (but no + * more), but will know the complete type information about `struct A`. While + * for CU #2, it will know full type information about `struct B`, but will + * only know about forward declaration of `struct A` (in BTF terms, it will + * have `BTF_KIND_FWD` type descriptor with name `B`). + * + * This compilation unit isolation means that it's possible that there is no + * single CU with complete type information describing structs `S`, `A`, and + * `B`. Also, we might get tons of duplicated and redundant type information. + * + * Additional complication we need to keep in mind comes from the fact that + * types, in general, can form graphs containing cycles, not just DAGs. + * + * While algorithm does deduplication, it also merges and resolves type + * information (unless disabled throught `struct btf_opts`), whenever possible. + * E.g., in the example above with two compilation units having partial type + * information for structs `A` and `B`, the output of algorithm will emit + * a single copy of each BTF type that describes structs `A`, `B`, and `S` + * (as well as type information for `int` and pointers), as if they were defined + * in a single compilation unit as: + * + * struct A { + * int a; + * struct A* self; + * struct S* parent; + * }; + * struct B { + * int b; + * struct B* self; + * struct S* parent; + * }; + * struct S { + * struct A* a_ptr; + * struct B* b_ptr; + * }; + * + * Algorithm summary + * ================= + * + * Algorithm completes its work in 6 separate passes: + * + * 1. Strings deduplication. + * 2. Primitive types deduplication (int, enum, fwd). + * 3. Struct/union types deduplication. + * 4. Reference types deduplication (pointers, typedefs, arrays, funcs, func + * protos, and const/volatile/restrict modifiers). + * 5. Types compaction. + * 6. Types remapping. + * + * Algorithm determines canonical type descriptor, which is a single + * representative type for each truly unique type. This canonical type is the + * one that will go into final deduplicated BTF type information. For + * struct/unions, it is also the type that algorithm will merge additional type + * information into (while resolving FWDs), as it discovers it from data in + * other CUs. Each input BTF type eventually gets either mapped to itself, if + * that type is canonical, or to some other type, if that type is equivalent + * and was chosen as canonical representative. This mapping is stored in + * `btf_dedup->map` array. This map is also used to record STRUCT/UNION that + * FWD type got resolved to. + * + * To facilitate fast discovery of canonical types, we also maintain canonical + * index (`btf_dedup->dedup_table`), which maps type descriptor's signature hash + * (i.e., hashed kind, name, size, fields, etc) into a list of canonical types + * that match that signature. With sufficiently good choice of type signature + * hashing function, we can limit number of canonical types for each unique type + * signature to a very small number, allowing to find canonical type for any + * duplicated type very quickly. + * + * Struct/union deduplication is the most critical part and algorithm for + * deduplicating structs/unions is described in greater details in comments for + * `btf_dedup_is_equiv` function. + */ +int btf__dedup(struct btf *btf, struct btf_ext *btf_ext, + const struct btf_dedup_opts *opts) +{ + struct btf_dedup *d = btf_dedup_new(btf, btf_ext, opts); + int err; + + if (IS_ERR(d)) { + pr_debug("btf_dedup_new failed: %ld", PTR_ERR(d)); + return -EINVAL; + } + + err = btf_dedup_strings(d); + if (err < 0) { + pr_debug("btf_dedup_strings failed:%d\n", err); + goto done; + } + err = btf_dedup_prim_types(d); + if (err < 0) { + pr_debug("btf_dedup_prim_types failed:%d\n", err); + goto done; + } + err = btf_dedup_struct_types(d); + if (err < 0) { + pr_debug("btf_dedup_struct_types failed:%d\n", err); + goto done; + } + err = btf_dedup_ref_types(d); + if (err < 0) { + pr_debug("btf_dedup_ref_types failed:%d\n", err); + goto done; + } + err = btf_dedup_compact_types(d); + if (err < 0) { + pr_debug("btf_dedup_compact_types failed:%d\n", err); + goto done; + } + err = btf_dedup_remap_types(d); + if (err < 0) { + pr_debug("btf_dedup_remap_types failed:%d\n", err); + goto done; + } + +done: + btf_dedup_free(d); + return err; +} + +#define BTF_DEDUP_TABLE_SIZE_LOG 14 +#define BTF_DEDUP_TABLE_MOD ((1 << BTF_DEDUP_TABLE_SIZE_LOG) - 1) +#define BTF_UNPROCESSED_ID ((__u32)-1) +#define BTF_IN_PROGRESS_ID ((__u32)-2) + +struct btf_dedup_node { + struct btf_dedup_node *next; + __u32 type_id; +}; + +struct btf_dedup { + /* .BTF section to be deduped in-place */ + struct btf *btf; + /* + * Optional .BTF.ext section. When provided, any strings referenced + * from it will be taken into account when deduping strings + */ + struct btf_ext *btf_ext; + /* + * This is a map from any type's signature hash to a list of possible + * canonical representative type candidates. Hash collisions are + * ignored, so even types of various kinds can share same list of + * candidates, which is fine because we rely on subsequent + * btf_xxx_equal() checks to authoritatively verify type equality. + */ + struct btf_dedup_node **dedup_table; + /* Canonical types map */ + __u32 *map; + /* Hypothetical mapping, used during type graph equivalence checks */ + __u32 *hypot_map; + __u32 *hypot_list; + size_t hypot_cnt; + size_t hypot_cap; + /* Various option modifying behavior of algorithm */ + struct btf_dedup_opts opts; +}; + +struct btf_str_ptr { + const char *str; + __u32 new_off; + bool used; +}; + +struct btf_str_ptrs { + struct btf_str_ptr *ptrs; + const char *data; + __u32 cnt; + __u32 cap; +}; + +static inline __u32 hash_combine(__u32 h, __u32 value) +{ +/* 2^31 + 2^29 - 2^25 + 2^22 - 2^19 - 2^16 + 1 */ +#define GOLDEN_RATIO_PRIME 0x9e370001UL + return h * 37 + value * GOLDEN_RATIO_PRIME; +#undef GOLDEN_RATIO_PRIME +} + +#define for_each_hash_node(table, hash, node) \ + for (node = table[hash & BTF_DEDUP_TABLE_MOD]; node; node = node->next) + +static int btf_dedup_table_add(struct btf_dedup *d, __u32 hash, __u32 type_id) +{ + struct btf_dedup_node *node = malloc(sizeof(struct btf_dedup_node)); + + if (!node) + return -ENOMEM; + node->type_id = type_id; + node->next = d->dedup_table[hash & BTF_DEDUP_TABLE_MOD]; + d->dedup_table[hash & BTF_DEDUP_TABLE_MOD] = node; + return 0; +} + +static int btf_dedup_hypot_map_add(struct btf_dedup *d, + __u32 from_id, __u32 to_id) +{ + if (d->hypot_cnt == d->hypot_cap) { + __u32 *new_list; + + d->hypot_cap += max(16, d->hypot_cap / 2); + new_list = realloc(d->hypot_list, sizeof(__u32) * d->hypot_cap); + if (!new_list) + return -ENOMEM; + d->hypot_list = new_list; + } + d->hypot_list[d->hypot_cnt++] = from_id; + d->hypot_map[from_id] = to_id; + return 0; +} + +static void btf_dedup_clear_hypot_map(struct btf_dedup *d) +{ + int i; + + for (i = 0; i < d->hypot_cnt; i++) + d->hypot_map[d->hypot_list[i]] = BTF_UNPROCESSED_ID; + d->hypot_cnt = 0; +} + +static void btf_dedup_table_free(struct btf_dedup *d) +{ + struct btf_dedup_node *head, *tmp; + int i; + + if (!d->dedup_table) + return; + + for (i = 0; i < (1 << BTF_DEDUP_TABLE_SIZE_LOG); i++) { + while (d->dedup_table[i]) { + tmp = d->dedup_table[i]; + d->dedup_table[i] = tmp->next; + free(tmp); + } + + head = d->dedup_table[i]; + while (head) { + tmp = head; + head = head->next; + free(tmp); + } + } + + free(d->dedup_table); + d->dedup_table = NULL; +} + +static void btf_dedup_free(struct btf_dedup *d) +{ + btf_dedup_table_free(d); + + free(d->map); + d->map = NULL; + + free(d->hypot_map); + d->hypot_map = NULL; + + free(d->hypot_list); + d->hypot_list = NULL; + + free(d); +} + +static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, + const struct btf_dedup_opts *opts) +{ + struct btf_dedup *d = calloc(1, sizeof(struct btf_dedup)); + int i, err = 0; + + if (!d) + return ERR_PTR(-ENOMEM); + + d->btf = btf; + d->btf_ext = btf_ext; + + d->dedup_table = calloc(1 << BTF_DEDUP_TABLE_SIZE_LOG, + sizeof(struct btf_dedup_node *)); + if (!d->dedup_table) { + err = -ENOMEM; + goto done; + } + + d->map = malloc(sizeof(__u32) * (1 + btf->nr_types)); + if (!d->map) { + err = -ENOMEM; + goto done; + } + /* special BTF "void" type is made canonical immediately */ + d->map[0] = 0; + for (i = 1; i <= btf->nr_types; i++) + d->map[i] = BTF_UNPROCESSED_ID; + + d->hypot_map = malloc(sizeof(__u32) * (1 + btf->nr_types)); + if (!d->hypot_map) { + err = -ENOMEM; + goto done; + } + for (i = 0; i <= btf->nr_types; i++) + d->hypot_map[i] = BTF_UNPROCESSED_ID; + + d->opts.dont_resolve_fwds = opts && opts->dont_resolve_fwds; + +done: + if (err) { + btf_dedup_free(d); + return ERR_PTR(err); + } + + return d; +} + +typedef int (*str_off_fn_t)(__u32 *str_off_ptr, void *ctx); + +/* + * Iterate over all possible places in .BTF and .BTF.ext that can reference + * string and pass pointer to it to a provided callback `fn`. + */ +static int btf_for_each_str_off(struct btf_dedup *d, str_off_fn_t fn, void *ctx) +{ + void *line_data_cur, *line_data_end; + int i, j, r, rec_size; + struct btf_type *t; + + for (i = 1; i <= d->btf->nr_types; i++) { + t = d->btf->types[i]; + r = fn(&t->name_off, ctx); + if (r) + return r; + + switch (BTF_INFO_KIND(t->info)) { + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + struct btf_member *m = (struct btf_member *)(t + 1); + __u16 vlen = BTF_INFO_VLEN(t->info); + + for (j = 0; j < vlen; j++) { + r = fn(&m->name_off, ctx); + if (r) + return r; + m++; + } + break; + } + case BTF_KIND_ENUM: { + struct btf_enum *m = (struct btf_enum *)(t + 1); + __u16 vlen = BTF_INFO_VLEN(t->info); + + for (j = 0; j < vlen; j++) { + r = fn(&m->name_off, ctx); + if (r) + return r; + m++; + } + break; + } + case BTF_KIND_FUNC_PROTO: { + struct btf_param *m = (struct btf_param *)(t + 1); + __u16 vlen = BTF_INFO_VLEN(t->info); + + for (j = 0; j < vlen; j++) { + r = fn(&m->name_off, ctx); + if (r) + return r; + m++; + } + break; + } + default: + break; + } + } + + if (!d->btf_ext) + return 0; + + line_data_cur = d->btf_ext->line_info.info; + line_data_end = d->btf_ext->line_info.info + d->btf_ext->line_info.len; + rec_size = d->btf_ext->line_info.rec_size; + + while (line_data_cur < line_data_end) { + struct btf_ext_info_sec *sec = line_data_cur; + struct bpf_line_info_min *line_info; + __u32 num_info = sec->num_info; + + r = fn(&sec->sec_name_off, ctx); + if (r) + return r; + + line_data_cur += sizeof(struct btf_ext_info_sec); + for (i = 0; i < num_info; i++) { + line_info = line_data_cur; + r = fn(&line_info->file_name_off, ctx); + if (r) + return r; + r = fn(&line_info->line_off, ctx); + if (r) + return r; + line_data_cur += rec_size; + } + } + + return 0; +} + +static int str_sort_by_content(const void *a1, const void *a2) +{ + const struct btf_str_ptr *p1 = a1; + const struct btf_str_ptr *p2 = a2; + + return strcmp(p1->str, p2->str); +} + +static int str_sort_by_offset(const void *a1, const void *a2) +{ + const struct btf_str_ptr *p1 = a1; + const struct btf_str_ptr *p2 = a2; + + if (p1->str != p2->str) + return p1->str < p2->str ? -1 : 1; + return 0; +} + +static int btf_dedup_str_ptr_cmp(const void *str_ptr, const void *pelem) +{ + const struct btf_str_ptr *p = pelem; + + if (str_ptr != p->str) + return (const char *)str_ptr < p->str ? -1 : 1; + return 0; +} + +static int btf_str_mark_as_used(__u32 *str_off_ptr, void *ctx) +{ + struct btf_str_ptrs *strs; + struct btf_str_ptr *s; + + if (*str_off_ptr == 0) + return 0; + + strs = ctx; + s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt, + sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp); + if (!s) + return -EINVAL; + s->used = true; + return 0; +} + +static int btf_str_remap_offset(__u32 *str_off_ptr, void *ctx) +{ + struct btf_str_ptrs *strs; + struct btf_str_ptr *s; + + if (*str_off_ptr == 0) + return 0; + + strs = ctx; + s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt, + sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp); + if (!s) + return -EINVAL; + *str_off_ptr = s->new_off; + return 0; +} + +/* + * Dedup string and filter out those that are not referenced from either .BTF + * or .BTF.ext (if provided) sections. + * + * This is done by building index of all strings in BTF's string section, + * then iterating over all entities that can reference strings (e.g., type + * names, struct field names, .BTF.ext line info, etc) and marking corresponding + * strings as used. After that all used strings are deduped and compacted into + * sequential blob of memory and new offsets are calculated. Then all the string + * references are iterated again and rewritten using new offsets. + */ +static int btf_dedup_strings(struct btf_dedup *d) +{ + const struct btf_header *hdr = d->btf->hdr; + char *start = (char *)d->btf->nohdr_data + hdr->str_off; + char *end = start + d->btf->hdr->str_len; + char *p = start, *tmp_strs = NULL; + struct btf_str_ptrs strs = { + .cnt = 0, + .cap = 0, + .ptrs = NULL, + .data = start, + }; + int i, j, err = 0, grp_idx; + bool grp_used; + + /* build index of all strings */ + while (p < end) { + if (strs.cnt + 1 > strs.cap) { + struct btf_str_ptr *new_ptrs; + + strs.cap += max(strs.cnt / 2, 16); + new_ptrs = realloc(strs.ptrs, + sizeof(strs.ptrs[0]) * strs.cap); + if (!new_ptrs) { + err = -ENOMEM; + goto done; + } + strs.ptrs = new_ptrs; + } + + strs.ptrs[strs.cnt].str = p; + strs.ptrs[strs.cnt].used = false; + + p += strlen(p) + 1; + strs.cnt++; + } + + /* temporary storage for deduplicated strings */ + tmp_strs = malloc(d->btf->hdr->str_len); + if (!tmp_strs) { + err = -ENOMEM; + goto done; + } + + /* mark all used strings */ + strs.ptrs[0].used = true; + err = btf_for_each_str_off(d, btf_str_mark_as_used, &strs); + if (err) + goto done; + + /* sort strings by context, so that we can identify duplicates */ + qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_content); + + /* + * iterate groups of equal strings and if any instance in a group was + * referenced, emit single instance and remember new offset + */ + p = tmp_strs; + grp_idx = 0; + grp_used = strs.ptrs[0].used; + /* iterate past end to avoid code duplication after loop */ + for (i = 1; i <= strs.cnt; i++) { + /* + * when i == strs.cnt, we want to skip string comparison and go + * straight to handling last group of strings (otherwise we'd + * need to handle last group after the loop w/ duplicated code) + */ + if (i < strs.cnt && + !strcmp(strs.ptrs[i].str, strs.ptrs[grp_idx].str)) { + grp_used = grp_used || strs.ptrs[i].used; + continue; + } + + /* + * this check would have been required after the loop to handle + * last group of strings, but due to <= condition in a loop + * we avoid that duplication + */ + if (grp_used) { + int new_off = p - tmp_strs; + __u32 len = strlen(strs.ptrs[grp_idx].str); + + memmove(p, strs.ptrs[grp_idx].str, len + 1); + for (j = grp_idx; j < i; j++) + strs.ptrs[j].new_off = new_off; + p += len + 1; + } + + if (i < strs.cnt) { + grp_idx = i; + grp_used = strs.ptrs[i].used; + } + } + + /* replace original strings with deduped ones */ + d->btf->hdr->str_len = p - tmp_strs; + memmove(start, tmp_strs, d->btf->hdr->str_len); + end = start + d->btf->hdr->str_len; + + /* restore original order for further binary search lookups */ + qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_offset); + + /* remap string offsets */ + err = btf_for_each_str_off(d, btf_str_remap_offset, &strs); + if (err) + goto done; + + d->btf->hdr->str_len = end - start; + +done: + free(tmp_strs); + free(strs.ptrs); + return err; +} + +static __u32 btf_hash_common(struct btf_type *t) +{ + __u32 h; + + h = hash_combine(0, t->name_off); + h = hash_combine(h, t->info); + h = hash_combine(h, t->size); + return h; +} + +static bool btf_equal_common(struct btf_type *t1, struct btf_type *t2) +{ + return t1->name_off == t2->name_off && + t1->info == t2->info && + t1->size == t2->size; +} + +/* Calculate type signature hash of INT. */ +static __u32 btf_hash_int(struct btf_type *t) +{ + __u32 info = *(__u32 *)(t + 1); + __u32 h; + + h = btf_hash_common(t); + h = hash_combine(h, info); + return h; +} + +/* Check structural equality of two INTs. */ +static bool btf_equal_int(struct btf_type *t1, struct btf_type *t2) +{ + __u32 info1, info2; + + if (!btf_equal_common(t1, t2)) + return false; + info1 = *(__u32 *)(t1 + 1); + info2 = *(__u32 *)(t2 + 1); + return info1 == info2; +} + +/* Calculate type signature hash of ENUM. */ +static __u32 btf_hash_enum(struct btf_type *t) +{ + struct btf_enum *member = (struct btf_enum *)(t + 1); + __u32 vlen = BTF_INFO_VLEN(t->info); + __u32 h = btf_hash_common(t); + int i; + + for (i = 0; i < vlen; i++) { + h = hash_combine(h, member->name_off); + h = hash_combine(h, member->val); + member++; + } + return h; +} + +/* Check structural equality of two ENUMs. */ +static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2) +{ + struct btf_enum *m1, *m2; + __u16 vlen; + int i; + + if (!btf_equal_common(t1, t2)) + return false; + + vlen = BTF_INFO_VLEN(t1->info); + m1 = (struct btf_enum *)(t1 + 1); + m2 = (struct btf_enum *)(t2 + 1); + for (i = 0; i < vlen; i++) { + if (m1->name_off != m2->name_off || m1->val != m2->val) + return false; + m1++; + m2++; + } + return true; +} + +/* + * Calculate type signature hash of STRUCT/UNION, ignoring referenced type IDs, + * as referenced type IDs equivalence is established separately during type + * graph equivalence check algorithm. + */ +static __u32 btf_hash_struct(struct btf_type *t) +{ + struct btf_member *member = (struct btf_member *)(t + 1); + __u32 vlen = BTF_INFO_VLEN(t->info); + __u32 h = btf_hash_common(t); + int i; + + for (i = 0; i < vlen; i++) { + h = hash_combine(h, member->name_off); + h = hash_combine(h, member->offset); + /* no hashing of referenced type ID, it can be unresolved yet */ + member++; + } + return h; +} + +/* + * Check structural compatibility of two FUNC_PROTOs, ignoring referenced type + * IDs. This check is performed during type graph equivalence check and + * referenced types equivalence is checked separately. + */ +static bool btf_equal_struct(struct btf_type *t1, struct btf_type *t2) +{ + struct btf_member *m1, *m2; + __u16 vlen; + int i; + + if (!btf_equal_common(t1, t2)) + return false; + + vlen = BTF_INFO_VLEN(t1->info); + m1 = (struct btf_member *)(t1 + 1); + m2 = (struct btf_member *)(t2 + 1); + for (i = 0; i < vlen; i++) { + if (m1->name_off != m2->name_off || m1->offset != m2->offset) + return false; + m1++; + m2++; + } + return true; +} + +/* + * Calculate type signature hash of ARRAY, including referenced type IDs, + * under assumption that they were already resolved to canonical type IDs and + * are not going to change. + */ +static __u32 btf_hash_array(struct btf_type *t) +{ + struct btf_array *info = (struct btf_array *)(t + 1); + __u32 h = btf_hash_common(t); + + h = hash_combine(h, info->type); + h = hash_combine(h, info->index_type); + h = hash_combine(h, info->nelems); + return h; +} + +/* + * Check exact equality of two ARRAYs, taking into account referenced + * type IDs, under assumption that they were already resolved to canonical + * type IDs and are not going to change. + * This function is called during reference types deduplication to compare + * ARRAY to potential canonical representative. + */ +static bool btf_equal_array(struct btf_type *t1, struct btf_type *t2) +{ + struct btf_array *info1, *info2; + + if (!btf_equal_common(t1, t2)) + return false; + + info1 = (struct btf_array *)(t1 + 1); + info2 = (struct btf_array *)(t2 + 1); + return info1->type == info2->type && + info1->index_type == info2->index_type && + info1->nelems == info2->nelems; +} + +/* + * Check structural compatibility of two ARRAYs, ignoring referenced type + * IDs. This check is performed during type graph equivalence check and + * referenced types equivalence is checked separately. + */ +static bool btf_compat_array(struct btf_type *t1, struct btf_type *t2) +{ + struct btf_array *info1, *info2; + + if (!btf_equal_common(t1, t2)) + return false; + + info1 = (struct btf_array *)(t1 + 1); + info2 = (struct btf_array *)(t2 + 1); + return info1->nelems == info2->nelems; +} + +/* + * Calculate type signature hash of FUNC_PROTO, including referenced type IDs, + * under assumption that they were already resolved to canonical type IDs and + * are not going to change. + */ +static inline __u32 btf_hash_fnproto(struct btf_type *t) +{ + struct btf_param *member = (struct btf_param *)(t + 1); + __u16 vlen = BTF_INFO_VLEN(t->info); + __u32 h = btf_hash_common(t); + int i; + + for (i = 0; i < vlen; i++) { + h = hash_combine(h, member->name_off); + h = hash_combine(h, member->type); + member++; + } + return h; +} + +/* + * Check exact equality of two FUNC_PROTOs, taking into account referenced + * type IDs, under assumption that they were already resolved to canonical + * type IDs and are not going to change. + * This function is called during reference types deduplication to compare + * FUNC_PROTO to potential canonical representative. + */ +static inline bool btf_equal_fnproto(struct btf_type *t1, struct btf_type *t2) +{ + struct btf_param *m1, *m2; + __u16 vlen; + int i; + + if (!btf_equal_common(t1, t2)) + return false; + + vlen = BTF_INFO_VLEN(t1->info); + m1 = (struct btf_param *)(t1 + 1); + m2 = (struct btf_param *)(t2 + 1); + for (i = 0; i < vlen; i++) { + if (m1->name_off != m2->name_off || m1->type != m2->type) + return false; + m1++; + m2++; + } + return true; +} + +/* + * Check structural compatibility of two FUNC_PROTOs, ignoring referenced type + * IDs. This check is performed during type graph equivalence check and + * referenced types equivalence is checked separately. + */ +static inline bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2) +{ + struct btf_param *m1, *m2; + __u16 vlen; + int i; + + /* skip return type ID */ + if (t1->name_off != t2->name_off || t1->info != t2->info) + return false; + + vlen = BTF_INFO_VLEN(t1->info); + m1 = (struct btf_param *)(t1 + 1); + m2 = (struct btf_param *)(t2 + 1); + for (i = 0; i < vlen; i++) { + if (m1->name_off != m2->name_off) + return false; + m1++; + m2++; + } + return true; +} + +/* + * Deduplicate primitive types, that can't reference other types, by calculating + * their type signature hash and comparing them with any possible canonical + * candidate. If no canonical candidate matches, type itself is marked as + * canonical and is added into `btf_dedup->dedup_table` as another candidate. + */ +static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) +{ + struct btf_type *t = d->btf->types[type_id]; + struct btf_type *cand; + struct btf_dedup_node *cand_node; + /* if we don't find equivalent type, then we are canonical */ + __u32 new_id = type_id; + __u32 h; + + switch (BTF_INFO_KIND(t->info)) { + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_ARRAY: + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_FUNC: + case BTF_KIND_FUNC_PROTO: + return 0; + + case BTF_KIND_INT: + h = btf_hash_int(t); + for_each_hash_node(d->dedup_table, h, cand_node) { + cand = d->btf->types[cand_node->type_id]; + if (btf_equal_int(t, cand)) { + new_id = cand_node->type_id; + break; + } + } + break; + + case BTF_KIND_ENUM: + h = btf_hash_enum(t); + for_each_hash_node(d->dedup_table, h, cand_node) { + cand = d->btf->types[cand_node->type_id]; + if (btf_equal_enum(t, cand)) { + new_id = cand_node->type_id; + break; + } + } + break; + + case BTF_KIND_FWD: + h = btf_hash_common(t); + for_each_hash_node(d->dedup_table, h, cand_node) { + cand = d->btf->types[cand_node->type_id]; + if (btf_equal_common(t, cand)) { + new_id = cand_node->type_id; + break; + } + } + break; + + default: + return -EINVAL; + } + + d->map[type_id] = new_id; + if (type_id == new_id && btf_dedup_table_add(d, h, type_id)) + return -ENOMEM; + + return 0; +} + +static int btf_dedup_prim_types(struct btf_dedup *d) +{ + int i, err; + + for (i = 1; i <= d->btf->nr_types; i++) { + err = btf_dedup_prim_type(d, i); + if (err) + return err; + } + return 0; +} + +/* + * Check whether type is already mapped into canonical one (could be to itself). + */ +static inline bool is_type_mapped(struct btf_dedup *d, uint32_t type_id) +{ + return d->map[type_id] <= BTF_MAX_TYPE; +} + +/* + * Resolve type ID into its canonical type ID, if any; otherwise return original + * type ID. If type is FWD and is resolved into STRUCT/UNION already, follow + * STRUCT/UNION link and resolve it into canonical type ID as well. + */ +static inline __u32 resolve_type_id(struct btf_dedup *d, __u32 type_id) +{ + while (is_type_mapped(d, type_id) && d->map[type_id] != type_id) + type_id = d->map[type_id]; + return type_id; +} + +/* + * Resolve FWD to underlying STRUCT/UNION, if any; otherwise return original + * type ID. + */ +static uint32_t resolve_fwd_id(struct btf_dedup *d, uint32_t type_id) +{ + __u32 orig_type_id = type_id; + + if (BTF_INFO_KIND(d->btf->types[type_id]->info) != BTF_KIND_FWD) + return type_id; + + while (is_type_mapped(d, type_id) && d->map[type_id] != type_id) + type_id = d->map[type_id]; + + if (BTF_INFO_KIND(d->btf->types[type_id]->info) != BTF_KIND_FWD) + return type_id; + + return orig_type_id; +} + + +static inline __u16 btf_fwd_kind(struct btf_type *t) +{ + return BTF_INFO_KFLAG(t->info) ? BTF_KIND_UNION : BTF_KIND_STRUCT; +} + +/* + * Check equivalence of BTF type graph formed by candidate struct/union (we'll + * call it "candidate graph" in this description for brevity) to a type graph + * formed by (potential) canonical struct/union ("canonical graph" for brevity + * here, though keep in mind that not all types in canonical graph are + * necessarily canonical representatives themselves, some of them might be + * duplicates or its uniqueness might not have been established yet). + * Returns: + * - >0, if type graphs are equivalent; + * - 0, if not equivalent; + * - <0, on error. + * + * Algorithm performs side-by-side DFS traversal of both type graphs and checks + * equivalence of BTF types at each step. If at any point BTF types in candidate + * and canonical graphs are not compatible structurally, whole graphs are + * incompatible. If types are structurally equivalent (i.e., all information + * except referenced type IDs is exactly the same), a mapping from `canon_id` to + * a `cand_id` is recored in hypothetical mapping (`btf_dedup->hypot_map`). + * If a type references other types, then those referenced types are checked + * for equivalence recursively. + * + * During DFS traversal, if we find that for current `canon_id` type we + * already have some mapping in hypothetical map, we check for two possible + * situations: + * - `canon_id` is mapped to exactly the same type as `cand_id`. This will + * happen when type graphs have cycles. In this case we assume those two + * types are equivalent. + * - `canon_id` is mapped to different type. This is contradiction in our + * hypothetical mapping, because same graph in canonical graph corresponds + * to two different types in candidate graph, which for equivalent type + * graphs shouldn't happen. This condition terminates equivalence check + * with negative result. + * + * If type graphs traversal exhausts types to check and find no contradiction, + * then type graphs are equivalent. + * + * When checking types for equivalence, there is one special case: FWD types. + * If FWD type resolution is allowed and one of the types (either from canonical + * or candidate graph) is FWD and other is STRUCT/UNION (depending on FWD's kind + * flag) and their names match, hypothetical mapping is updated to point from + * FWD to STRUCT/UNION. If graphs will be determined as equivalent successfully, + * this mapping will be used to record FWD -> STRUCT/UNION mapping permanently. + * + * Technically, this could lead to incorrect FWD to STRUCT/UNION resolution, + * if there are two exactly named (or anonymous) structs/unions that are + * compatible structurally, one of which has FWD field, while other is concrete + * STRUCT/UNION, but according to C sources they are different structs/unions + * that are referencing different types with the same name. This is extremely + * unlikely to happen, but btf_dedup API allows to disable FWD resolution if + * this logic is causing problems. + * + * Doing FWD resolution means that both candidate and/or canonical graphs can + * consists of portions of the graph that come from multiple compilation units. + * This is due to the fact that types within single compilation unit are always + * deduplicated and FWDs are already resolved, if referenced struct/union + * definiton is available. So, if we had unresolved FWD and found corresponding + * STRUCT/UNION, they will be from different compilation units. This + * consequently means that when we "link" FWD to corresponding STRUCT/UNION, + * type graph will likely have at least two different BTF types that describe + * same type (e.g., most probably there will be two different BTF types for the + * same 'int' primitive type) and could even have "overlapping" parts of type + * graph that describe same subset of types. + * + * This in turn means that our assumption that each type in canonical graph + * must correspond to exactly one type in candidate graph might not hold + * anymore and will make it harder to detect contradictions using hypothetical + * map. To handle this problem, we allow to follow FWD -> STRUCT/UNION + * resolution only in canonical graph. FWDs in candidate graphs are never + * resolved. To see why it's OK, let's check all possible situations w.r.t. FWDs + * that can occur: + * - Both types in canonical and candidate graphs are FWDs. If they are + * structurally equivalent, then they can either be both resolved to the + * same STRUCT/UNION or not resolved at all. In both cases they are + * equivalent and there is no need to resolve FWD on candidate side. + * - Both types in canonical and candidate graphs are concrete STRUCT/UNION, + * so nothing to resolve as well, algorithm will check equivalence anyway. + * - Type in canonical graph is FWD, while type in candidate is concrete + * STRUCT/UNION. In this case candidate graph comes from single compilation + * unit, so there is exactly one BTF type for each unique C type. After + * resolving FWD into STRUCT/UNION, there might be more than one BTF type + * in canonical graph mapping to single BTF type in candidate graph, but + * because hypothetical mapping maps from canonical to candidate types, it's + * alright, and we still maintain the property of having single `canon_id` + * mapping to single `cand_id` (there could be two different `canon_id` + * mapped to the same `cand_id`, but it's not contradictory). + * - Type in canonical graph is concrete STRUCT/UNION, while type in candidate + * graph is FWD. In this case we are just going to check compatibility of + * STRUCT/UNION and corresponding FWD, and if they are compatible, we'll + * assume that whatever STRUCT/UNION FWD resolves to must be equivalent to + * a concrete STRUCT/UNION from canonical graph. If the rest of type graphs + * turn out equivalent, we'll re-resolve FWD to concrete STRUCT/UNION from + * canonical graph. + */ +static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, + __u32 canon_id) +{ + struct btf_type *cand_type; + struct btf_type *canon_type; + __u32 hypot_type_id; + __u16 cand_kind; + __u16 canon_kind; + int i, eq; + + /* if both resolve to the same canonical, they must be equivalent */ + if (resolve_type_id(d, cand_id) == resolve_type_id(d, canon_id)) + return 1; + + canon_id = resolve_fwd_id(d, canon_id); + + hypot_type_id = d->hypot_map[canon_id]; + if (hypot_type_id <= BTF_MAX_TYPE) + return hypot_type_id == cand_id; + + if (btf_dedup_hypot_map_add(d, canon_id, cand_id)) + return -ENOMEM; + + cand_type = d->btf->types[cand_id]; + canon_type = d->btf->types[canon_id]; + cand_kind = BTF_INFO_KIND(cand_type->info); + canon_kind = BTF_INFO_KIND(canon_type->info); + + if (cand_type->name_off != canon_type->name_off) + return 0; + + /* FWD <--> STRUCT/UNION equivalence check, if enabled */ + if (!d->opts.dont_resolve_fwds + && (cand_kind == BTF_KIND_FWD || canon_kind == BTF_KIND_FWD) + && cand_kind != canon_kind) { + __u16 real_kind; + __u16 fwd_kind; + + if (cand_kind == BTF_KIND_FWD) { + real_kind = canon_kind; + fwd_kind = btf_fwd_kind(cand_type); + } else { + real_kind = cand_kind; + fwd_kind = btf_fwd_kind(canon_type); + } + return fwd_kind == real_kind; + } + + if (cand_type->info != canon_type->info) + return 0; + + switch (cand_kind) { + case BTF_KIND_INT: + return btf_equal_int(cand_type, canon_type); + + case BTF_KIND_ENUM: + return btf_equal_enum(cand_type, canon_type); + + case BTF_KIND_FWD: + return btf_equal_common(cand_type, canon_type); + + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + return btf_dedup_is_equiv(d, cand_type->type, canon_type->type); + + case BTF_KIND_ARRAY: { + struct btf_array *cand_arr, *canon_arr; + + if (!btf_compat_array(cand_type, canon_type)) + return 0; + cand_arr = (struct btf_array *)(cand_type + 1); + canon_arr = (struct btf_array *)(canon_type + 1); + eq = btf_dedup_is_equiv(d, + cand_arr->index_type, canon_arr->index_type); + if (eq <= 0) + return eq; + return btf_dedup_is_equiv(d, cand_arr->type, canon_arr->type); + } + + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + struct btf_member *cand_m, *canon_m; + __u16 vlen; + + if (!btf_equal_struct(cand_type, canon_type)) + return 0; + vlen = BTF_INFO_VLEN(cand_type->info); + cand_m = (struct btf_member *)(cand_type + 1); + canon_m = (struct btf_member *)(canon_type + 1); + for (i = 0; i < vlen; i++) { + eq = btf_dedup_is_equiv(d, cand_m->type, canon_m->type); + if (eq <= 0) + return eq; + cand_m++; + canon_m++; + } + + return 1; + } + + case BTF_KIND_FUNC_PROTO: { + struct btf_param *cand_p, *canon_p; + __u16 vlen; + + if (!btf_compat_fnproto(cand_type, canon_type)) + return 0; + eq = btf_dedup_is_equiv(d, cand_type->type, canon_type->type); + if (eq <= 0) + return eq; + vlen = BTF_INFO_VLEN(cand_type->info); + cand_p = (struct btf_param *)(cand_type + 1); + canon_p = (struct btf_param *)(canon_type + 1); + for (i = 0; i < vlen; i++) { + eq = btf_dedup_is_equiv(d, cand_p->type, canon_p->type); + if (eq <= 0) + return eq; + cand_p++; + canon_p++; + } + return 1; + } + + default: + return -EINVAL; + } + return 0; +} + +/* + * Use hypothetical mapping, produced by successful type graph equivalence + * check, to augment existing struct/union canonical mapping, where possible. + * + * If BTF_KIND_FWD resolution is allowed, this mapping is also used to record + * FWD -> STRUCT/UNION correspondence as well. FWD resolution is bidirectional: + * it doesn't matter if FWD type was part of canonical graph or candidate one, + * we are recording the mapping anyway. As opposed to carefulness required + * for struct/union correspondence mapping (described below), for FWD resolution + * it's not important, as by the time that FWD type (reference type) will be + * deduplicated all structs/unions will be deduped already anyway. + * + * Recording STRUCT/UNION mapping is purely a performance optimization and is + * not required for correctness. It needs to be done carefully to ensure that + * struct/union from candidate's type graph is not mapped into corresponding + * struct/union from canonical type graph that itself hasn't been resolved into + * canonical representative. The only guarantee we have is that canonical + * struct/union was determined as canonical and that won't change. But any + * types referenced through that struct/union fields could have been not yet + * resolved, so in case like that it's too early to establish any kind of + * correspondence between structs/unions. + * + * No canonical correspondence is derived for primitive types (they are already + * deduplicated completely already anyway) or reference types (they rely on + * stability of struct/union canonical relationship for equivalence checks). + */ +static void btf_dedup_merge_hypot_map(struct btf_dedup *d) +{ + __u32 cand_type_id, targ_type_id; + __u16 t_kind, c_kind; + __u32 t_id, c_id; + int i; + + for (i = 0; i < d->hypot_cnt; i++) { + cand_type_id = d->hypot_list[i]; + targ_type_id = d->hypot_map[cand_type_id]; + t_id = resolve_type_id(d, targ_type_id); + c_id = resolve_type_id(d, cand_type_id); + t_kind = BTF_INFO_KIND(d->btf->types[t_id]->info); + c_kind = BTF_INFO_KIND(d->btf->types[c_id]->info); + /* + * Resolve FWD into STRUCT/UNION. + * It's ok to resolve FWD into STRUCT/UNION that's not yet + * mapped to canonical representative (as opposed to + * STRUCT/UNION <--> STRUCT/UNION mapping logic below), because + * eventually that struct is going to be mapped and all resolved + * FWDs will automatically resolve to correct canonical + * representative. This will happen before ref type deduping, + * which critically depends on stability of these mapping. This + * stability is not a requirement for STRUCT/UNION equivalence + * checks, though. + */ + if (t_kind != BTF_KIND_FWD && c_kind == BTF_KIND_FWD) + d->map[c_id] = t_id; + else if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD) + d->map[t_id] = c_id; + + if ((t_kind == BTF_KIND_STRUCT || t_kind == BTF_KIND_UNION) && + c_kind != BTF_KIND_FWD && + is_type_mapped(d, c_id) && + !is_type_mapped(d, t_id)) { + /* + * as a perf optimization, we can map struct/union + * that's part of type graph we just verified for + * equivalence. We can do that for struct/union that has + * canonical representative only, though. + */ + d->map[t_id] = c_id; + } + } +} + +/* + * Deduplicate struct/union types. + * + * For each struct/union type its type signature hash is calculated, taking + * into account type's name, size, number, order and names of fields, but + * ignoring type ID's referenced from fields, because they might not be deduped + * completely until after reference types deduplication phase. This type hash + * is used to iterate over all potential canonical types, sharing same hash. + * For each canonical candidate we check whether type graphs that they form + * (through referenced types in fields and so on) are equivalent using algorithm + * implemented in `btf_dedup_is_equiv`. If such equivalence is found and + * BTF_KIND_FWD resolution is allowed, then hypothetical mapping + * (btf_dedup->hypot_map) produced by aforementioned type graph equivalence + * algorithm is used to record FWD -> STRUCT/UNION mapping. It's also used to + * potentially map other structs/unions to their canonical representatives, + * if such relationship hasn't yet been established. This speeds up algorithm + * by eliminating some of the duplicate work. + * + * If no matching canonical representative was found, struct/union is marked + * as canonical for itself and is added into btf_dedup->dedup_table hash map + * for further look ups. + */ +static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) +{ + struct btf_dedup_node *cand_node; + struct btf_type *t; + /* if we don't find equivalent type, then we are canonical */ + __u32 new_id = type_id; + __u16 kind; + __u32 h; + + /* already deduped or is in process of deduping (loop detected) */ + if (d->map[type_id] <= BTF_MAX_TYPE) + return 0; + + t = d->btf->types[type_id]; + kind = BTF_INFO_KIND(t->info); + + if (kind != BTF_KIND_STRUCT && kind != BTF_KIND_UNION) + return 0; + + h = btf_hash_struct(t); + for_each_hash_node(d->dedup_table, h, cand_node) { + int eq; + + btf_dedup_clear_hypot_map(d); + eq = btf_dedup_is_equiv(d, type_id, cand_node->type_id); + if (eq < 0) + return eq; + if (!eq) + continue; + new_id = cand_node->type_id; + btf_dedup_merge_hypot_map(d); + break; + } + + d->map[type_id] = new_id; + if (type_id == new_id && btf_dedup_table_add(d, h, type_id)) + return -ENOMEM; + + return 0; +} + +static int btf_dedup_struct_types(struct btf_dedup *d) +{ + int i, err; + + for (i = 1; i <= d->btf->nr_types; i++) { + err = btf_dedup_struct_type(d, i); + if (err) + return err; + } + return 0; +} + +/* + * Deduplicate reference type. + * + * Once all primitive and struct/union types got deduplicated, we can easily + * deduplicate all other (reference) BTF types. This is done in two steps: + * + * 1. Resolve all referenced type IDs into their canonical type IDs. This + * resolution can be done either immediately for primitive or struct/union types + * (because they were deduped in previous two phases) or recursively for + * reference types. Recursion will always terminate at either primitive or + * struct/union type, at which point we can "unwind" chain of reference types + * one by one. There is no danger of encountering cycles because in C type + * system the only way to form type cycle is through struct/union, so any chain + * of reference types, even those taking part in a type cycle, will inevitably + * reach struct/union at some point. + * + * 2. Once all referenced type IDs are resolved into canonical ones, BTF type + * becomes "stable", in the sense that no further deduplication will cause + * any changes to it. With that, it's now possible to calculate type's signature + * hash (this time taking into account referenced type IDs) and loop over all + * potential canonical representatives. If no match was found, current type + * will become canonical representative of itself and will be added into + * btf_dedup->dedup_table as another possible canonical representative. + */ +static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) +{ + struct btf_dedup_node *cand_node; + struct btf_type *t, *cand; + /* if we don't find equivalent type, then we are representative type */ + __u32 new_id = type_id; + __u32 h, ref_type_id; + + if (d->map[type_id] == BTF_IN_PROGRESS_ID) + return -ELOOP; + if (d->map[type_id] <= BTF_MAX_TYPE) + return resolve_type_id(d, type_id); + + t = d->btf->types[type_id]; + d->map[type_id] = BTF_IN_PROGRESS_ID; + + switch (BTF_INFO_KIND(t->info)) { + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + ref_type_id = btf_dedup_ref_type(d, t->type); + if (ref_type_id < 0) + return ref_type_id; + t->type = ref_type_id; + + h = btf_hash_common(t); + for_each_hash_node(d->dedup_table, h, cand_node) { + cand = d->btf->types[cand_node->type_id]; + if (btf_equal_common(t, cand)) { + new_id = cand_node->type_id; + break; + } + } + break; + + case BTF_KIND_ARRAY: { + struct btf_array *info = (struct btf_array *)(t + 1); + + ref_type_id = btf_dedup_ref_type(d, info->type); + if (ref_type_id < 0) + return ref_type_id; + info->type = ref_type_id; + + ref_type_id = btf_dedup_ref_type(d, info->index_type); + if (ref_type_id < 0) + return ref_type_id; + info->index_type = ref_type_id; + + h = btf_hash_array(t); + for_each_hash_node(d->dedup_table, h, cand_node) { + cand = d->btf->types[cand_node->type_id]; + if (btf_equal_array(t, cand)) { + new_id = cand_node->type_id; + break; + } + } + break; + } + + case BTF_KIND_FUNC_PROTO: { + struct btf_param *param; + __u16 vlen; + int i; + + ref_type_id = btf_dedup_ref_type(d, t->type); + if (ref_type_id < 0) + return ref_type_id; + t->type = ref_type_id; + + vlen = BTF_INFO_VLEN(t->info); + param = (struct btf_param *)(t + 1); + for (i = 0; i < vlen; i++) { + ref_type_id = btf_dedup_ref_type(d, param->type); + if (ref_type_id < 0) + return ref_type_id; + param->type = ref_type_id; + param++; + } + + h = btf_hash_fnproto(t); + for_each_hash_node(d->dedup_table, h, cand_node) { + cand = d->btf->types[cand_node->type_id]; + if (btf_equal_fnproto(t, cand)) { + new_id = cand_node->type_id; + break; + } + } + break; + } + + default: + return -EINVAL; + } + + d->map[type_id] = new_id; + if (type_id == new_id && btf_dedup_table_add(d, h, type_id)) + return -ENOMEM; + + return new_id; +} + +static int btf_dedup_ref_types(struct btf_dedup *d) +{ + int i, err; + + for (i = 1; i <= d->btf->nr_types; i++) { + err = btf_dedup_ref_type(d, i); + if (err < 0) + return err; + } + btf_dedup_table_free(d); + return 0; +} + +/* + * Compact types. + * + * After we established for each type its corresponding canonical representative + * type, we now can eliminate types that are not canonical and leave only + * canonical ones layed out sequentially in memory by copying them over + * duplicates. During compaction btf_dedup->hypot_map array is reused to store + * a map from original type ID to a new compacted type ID, which will be used + * during next phase to "fix up" type IDs, referenced from struct/union and + * reference types. + */ +static int btf_dedup_compact_types(struct btf_dedup *d) +{ + struct btf_type **new_types; + __u32 next_type_id = 1; + char *types_start, *p; + int i, len; + + /* we are going to reuse hypot_map to store compaction remapping */ + d->hypot_map[0] = 0; + for (i = 1; i <= d->btf->nr_types; i++) + d->hypot_map[i] = BTF_UNPROCESSED_ID; + + types_start = d->btf->nohdr_data + d->btf->hdr->type_off; + p = types_start; + + for (i = 1; i <= d->btf->nr_types; i++) { + if (d->map[i] != i) + continue; + + len = btf_type_size(d->btf->types[i]); + if (len < 0) + return len; + + memmove(p, d->btf->types[i], len); + d->hypot_map[i] = next_type_id; + d->btf->types[next_type_id] = (struct btf_type *)p; + p += len; + next_type_id++; + } + + /* shrink struct btf's internal types index and update btf_header */ + d->btf->nr_types = next_type_id - 1; + d->btf->types_size = d->btf->nr_types; + d->btf->hdr->type_len = p - types_start; + new_types = realloc(d->btf->types, + (1 + d->btf->nr_types) * sizeof(struct btf_type *)); + if (!new_types) + return -ENOMEM; + d->btf->types = new_types; + + /* make sure string section follows type information without gaps */ + d->btf->hdr->str_off = p - (char *)d->btf->nohdr_data; + memmove(p, d->btf->strings, d->btf->hdr->str_len); + d->btf->strings = p; + p += d->btf->hdr->str_len; + + d->btf->data_size = p - (char *)d->btf->data; + return 0; +} + +/* + * Figure out final (deduplicated and compacted) type ID for provided original + * `type_id` by first resolving it into corresponding canonical type ID and + * then mapping it to a deduplicated type ID, stored in btf_dedup->hypot_map, + * which is populated during compaction phase. + */ +static int btf_dedup_remap_type_id(struct btf_dedup *d, __u32 type_id) +{ + __u32 resolved_type_id, new_type_id; + + resolved_type_id = resolve_type_id(d, type_id); + new_type_id = d->hypot_map[resolved_type_id]; + if (new_type_id > BTF_MAX_TYPE) + return -EINVAL; + return new_type_id; +} + +/* + * Remap referenced type IDs into deduped type IDs. + * + * After BTF types are deduplicated and compacted, their final type IDs may + * differ from original ones. The map from original to a corresponding + * deduped type ID is stored in btf_dedup->hypot_map and is populated during + * compaction phase. During remapping phase we are rewriting all type IDs + * referenced from any BTF type (e.g., struct fields, func proto args, etc) to + * their final deduped type IDs. + */ +static int btf_dedup_remap_type(struct btf_dedup *d, __u32 type_id) +{ + struct btf_type *t = d->btf->types[type_id]; + int i, r; + + switch (BTF_INFO_KIND(t->info)) { + case BTF_KIND_INT: + case BTF_KIND_ENUM: + break; + + case BTF_KIND_FWD: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + r = btf_dedup_remap_type_id(d, t->type); + if (r < 0) + return r; + t->type = r; + break; + + case BTF_KIND_ARRAY: { + struct btf_array *arr_info = (struct btf_array *)(t + 1); + + r = btf_dedup_remap_type_id(d, arr_info->type); + if (r < 0) + return r; + arr_info->type = r; + r = btf_dedup_remap_type_id(d, arr_info->index_type); + if (r < 0) + return r; + arr_info->index_type = r; + break; + } + + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + struct btf_member *member = (struct btf_member *)(t + 1); + __u16 vlen = BTF_INFO_VLEN(t->info); + + for (i = 0; i < vlen; i++) { + r = btf_dedup_remap_type_id(d, member->type); + if (r < 0) + return r; + member->type = r; + member++; + } + break; + } + + case BTF_KIND_FUNC_PROTO: { + struct btf_param *param = (struct btf_param *)(t + 1); + __u16 vlen = BTF_INFO_VLEN(t->info); + + r = btf_dedup_remap_type_id(d, t->type); + if (r < 0) + return r; + t->type = r; + + for (i = 0; i < vlen; i++) { + r = btf_dedup_remap_type_id(d, param->type); + if (r < 0) + return r; + param->type = r; + param++; + } + break; + } + + default: + return -EINVAL; + } + + return 0; +} + +static int btf_dedup_remap_types(struct btf_dedup *d) +{ + int i, r; + + for (i = 1; i <= d->btf->nr_types; i++) { + r = btf_dedup_remap_type(d, i); + if (r < 0) + return r; + } + return 0; +} diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 258c87e9f55d..25a9d2db035d 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -59,11 +59,14 @@ LIBBPF_API void btf__free(struct btf *btf); LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size); LIBBPF_API __s32 btf__find_by_name(const struct btf *btf, const char *type_name); +LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf); LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 id); LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id); LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id); LIBBPF_API int btf__fd(const struct btf *btf); +LIBBPF_API void btf__get_strings(const struct btf *btf, const char **strings, + __u32 *str_len); LIBBPF_API const char *btf__name_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, char *map_name, @@ -84,6 +87,13 @@ LIBBPF_API int btf_ext__reloc_line_info(const struct btf *btf, LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext); LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext); +struct btf_dedup_opts { + bool dont_resolve_fwds; +}; + +LIBBPF_API int btf__dedup(struct btf *btf, struct btf_ext *btf_ext, + const struct btf_dedup_opts *opts); + #ifdef __cplusplus } /* extern "C" */ #endif diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 7990e857e003..89c1149e32ee 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -133,7 +133,10 @@ LIBBPF_0.0.2 { bpf_map_lookup_elem_flags; bpf_object__find_map_fd_by_name; bpf_get_link_xdp_id; + btf__dedup; btf__get_map_kv_tids; + btf__get_nr_types; + btf__get_strings; btf_ext__free; btf_ext__func_info_rec_size; btf_ext__line_info_rec_size; diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c index 5afab823ffbe..30c3edde7e07 100644 --- a/tools/testing/selftests/bpf/test_btf.c +++ b/tools/testing/selftests/bpf/test_btf.c @@ -70,12 +70,21 @@ static int __base_pr(enum libbpf_print_level level __attribute__((unused)), BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \ BTF_INT_ENC(encoding, bits_offset, bits) +#define BTF_FWD_ENC(name, kind_flag) \ + BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FWD, kind_flag, 0), 0) + #define BTF_ARRAY_ENC(type, index_type, nr_elems) \ (type), (index_type), (nr_elems) #define BTF_TYPE_ARRAY_ENC(type, index_type, nr_elems) \ BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_ARRAY, 0, 0), 0), \ BTF_ARRAY_ENC(type, index_type, nr_elems) +#define BTF_STRUCT_ENC(name, nr_elems, sz) \ + BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, nr_elems), sz) + +#define BTF_UNION_ENC(name, nr_elems, sz) \ + BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_UNION, 0, nr_elems), sz) + #define BTF_MEMBER_ENC(name, type, bits_offset) \ (name), (type), (bits_offset) #define BTF_ENUM_ENC(name, val) (name), (val) @@ -91,6 +100,12 @@ static int __base_pr(enum libbpf_print_level level __attribute__((unused)), #define BTF_CONST_ENC(type) \ BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_CONST, 0, 0), type) +#define BTF_VOLATILE_ENC(type) \ + BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_VOLATILE, 0, 0), type) + +#define BTF_RESTRICT_ENC(type) \ + BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_RESTRICT, 0, 0), type) + #define BTF_FUNC_PROTO_ENC(ret_type, nargs) \ BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, nargs), ret_type) @@ -103,6 +118,10 @@ static int __base_pr(enum libbpf_print_level level __attribute__((unused)), #define BTF_END_RAW 0xdeadbeef #define NAME_TBD 0xdeadb33f +#define NAME_NTH(N) (0xffff0000 | N) +#define IS_NAME_NTH(X) ((X & 0xffff0000) == 0xffff0000) +#define GET_NAME_NTH_IDX(X) (X & 0x0000ffff) + #define MAX_NR_RAW_U32 1024 #define BTF_LOG_BUF_SIZE 65535 @@ -111,12 +130,14 @@ static struct args { unsigned int file_test_num; unsigned int get_info_test_num; unsigned int info_raw_test_num; + unsigned int dedup_test_num; bool raw_test; bool file_test; bool get_info_test; bool pprint_test; bool always_log; bool info_raw_test; + bool dedup_test; } args; static char btf_log_buf[BTF_LOG_BUF_SIZE]; @@ -2827,11 +2848,13 @@ static void *btf_raw_create(const struct btf_header *hdr, const char **ret_next_str) { const char *next_str = str, *end_str = str + str_sec_size; + const char **strs_idx = NULL, **tmp_strs_idx; + int strs_cap = 0, strs_cnt = 0, next_str_idx = 0; unsigned int size_needed, offset; struct btf_header *ret_hdr; - int i, type_sec_size; + int i, type_sec_size, err = 0; uint32_t *ret_types; - void *raw_btf; + void *raw_btf = NULL; type_sec_size = get_raw_sec_size(raw_types); if (CHECK(type_sec_size < 0, "Cannot get nr_raw_types")) @@ -2846,17 +2869,44 @@ static void *btf_raw_create(const struct btf_header *hdr, memcpy(raw_btf, hdr, sizeof(*hdr)); offset = sizeof(*hdr); + /* Index strings */ + while ((next_str = get_next_str(next_str, end_str))) { + if (strs_cnt == strs_cap) { + strs_cap += max(16, strs_cap / 2); + tmp_strs_idx = realloc(strs_idx, + sizeof(*strs_idx) * strs_cap); + if (CHECK(!tmp_strs_idx, + "Cannot allocate memory for strs_idx")) { + err = -1; + goto done; + } + strs_idx = tmp_strs_idx; + } + strs_idx[strs_cnt++] = next_str; + next_str += strlen(next_str); + } + /* Copy type section */ ret_types = raw_btf + offset; for (i = 0; i < type_sec_size / sizeof(raw_types[0]); i++) { if (raw_types[i] == NAME_TBD) { - next_str = get_next_str(next_str, end_str); - if (CHECK(!next_str, "Error in getting next_str")) { - free(raw_btf); - return NULL; + if (CHECK(next_str_idx == strs_cnt, + "Error in getting next_str #%d", + next_str_idx)) { + err = -1; + goto done; } - ret_types[i] = next_str - str; - next_str += strlen(next_str); + ret_types[i] = strs_idx[next_str_idx++] - str; + } else if (IS_NAME_NTH(raw_types[i])) { + int idx = GET_NAME_NTH_IDX(raw_types[i]); + + if (CHECK(idx <= 0 || idx > strs_cnt, + "Error getting string #%d, strs_cnt:%d", + idx, strs_cnt)) { + err = -1; + goto done; + } + ret_types[i] = strs_idx[idx-1] - str; } else { ret_types[i] = raw_types[i]; } @@ -2873,8 +2923,17 @@ static void *btf_raw_create(const struct btf_header *hdr, *btf_size = size_needed; if (ret_next_str) - *ret_next_str = next_str; + *ret_next_str = + next_str_idx < strs_cnt ? strs_idx[next_str_idx] : NULL; +done: + if (err) { + if (raw_btf) + free(raw_btf); + if (strs_idx) + free(strs_idx); + return NULL; + } return raw_btf; } @@ -5543,20 +5602,450 @@ static int test_info_raw(void) return err; } +struct btf_raw_data { + __u32 raw_types[MAX_NR_RAW_U32]; + const char *str_sec; + __u32 str_sec_size; +}; + +struct btf_dedup_test { + const char *descr; + struct btf_raw_data input; + struct btf_raw_data expect; + struct btf_dedup_opts opts; +}; + +const struct btf_dedup_test dedup_tests[] = { + +{ + .descr = "dedup: unused strings filtering", + .input = { + .raw_types = { + BTF_TYPE_INT_ENC(NAME_NTH(2), BTF_INT_SIGNED, 0, 32, 4), + BTF_TYPE_INT_ENC(NAME_NTH(5), BTF_INT_SIGNED, 0, 64, 8), + BTF_END_RAW, + }, + BTF_STR_SEC("\0unused\0int\0foo\0bar\0long"), + }, + .expect = { + .raw_types = { + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4), + BTF_TYPE_INT_ENC(NAME_NTH(2), BTF_INT_SIGNED, 0, 64, 8), + BTF_END_RAW, + }, + BTF_STR_SEC("\0int\0long"), + }, + .opts = { + .dont_resolve_fwds = false, + }, +}, +{ + .descr = "dedup: strings deduplication", + .input = { + .raw_types = { + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4), + BTF_TYPE_INT_ENC(NAME_NTH(2), BTF_INT_SIGNED, 0, 64, 8), + BTF_TYPE_INT_ENC(NAME_NTH(3), BTF_INT_SIGNED, 0, 32, 4), + BTF_TYPE_INT_ENC(NAME_NTH(4), BTF_INT_SIGNED, 0, 64, 8), + BTF_TYPE_INT_ENC(NAME_NTH(5), BTF_INT_SIGNED, 0, 32, 4), + BTF_END_RAW, + }, + BTF_STR_SEC("\0int\0long int\0int\0long int\0int"), + }, + .expect = { + .raw_types = { + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4), + BTF_TYPE_INT_ENC(NAME_NTH(2), BTF_INT_SIGNED, 0, 64, 8), + BTF_END_RAW, + }, + BTF_STR_SEC("\0int\0long int"), + }, + .opts = { + .dont_resolve_fwds = false, + }, +}, +{ + .descr = "dedup: struct example #1", + /* + * struct s { + * struct s *next; + * const int *a; + * int b[16]; + * int c; + * } + */ + .input = { + .raw_types = { + /* int */ + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + /* int[16] */ + BTF_TYPE_ARRAY_ENC(1, 1, 16), /* [2] */ + /* struct s { */ + BTF_STRUCT_ENC(NAME_NTH(2), 4, 84), /* [3] */ + BTF_MEMBER_ENC(NAME_NTH(3), 4, 0), /* struct s *next; */ + BTF_MEMBER_ENC(NAME_NTH(4), 5, 64), /* const int *a; */ + BTF_MEMBER_ENC(NAME_NTH(5), 2, 128), /* int b[16]; */ + BTF_MEMBER_ENC(NAME_NTH(6), 1, 640), /* int c; */ + /* ptr -> [3] struct s */ + BTF_PTR_ENC(3), /* [4] */ + /* ptr -> [6] const int */ + BTF_PTR_ENC(6), /* [5] */ + /* const -> [1] int */ + BTF_CONST_ENC(1), /* [6] */ + + /* full copy of the above */ + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4), /* [7] */ + BTF_TYPE_ARRAY_ENC(7, 7, 16), /* [8] */ + BTF_STRUCT_ENC(NAME_NTH(2), 4, 84), /* [9] */ + BTF_MEMBER_ENC(NAME_NTH(3), 10, 0), + BTF_MEMBER_ENC(NAME_NTH(4), 11, 64), + BTF_MEMBER_ENC(NAME_NTH(5), 8, 128), + BTF_MEMBER_ENC(NAME_NTH(6), 7, 640), + BTF_PTR_ENC(9), /* [10] */ + BTF_PTR_ENC(12), /* [11] */ + BTF_CONST_ENC(7), /* [12] */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0int\0s\0next\0a\0b\0c\0"), + }, + .expect = { + .raw_types = { + /* int */ + BTF_TYPE_INT_ENC(NAME_NTH(4), BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + /* int[16] */ + BTF_TYPE_ARRAY_ENC(1, 1, 16), /* [2] */ + /* struct s { */ + BTF_STRUCT_ENC(NAME_NTH(6), 4, 84), /* [3] */ + BTF_MEMBER_ENC(NAME_NTH(5), 4, 0), /* struct s *next; */ + BTF_MEMBER_ENC(NAME_NTH(1), 5, 64), /* const int *a; */ + BTF_MEMBER_ENC(NAME_NTH(2), 2, 128), /* int b[16]; */ + BTF_MEMBER_ENC(NAME_NTH(3), 1, 640), /* int c; */ + /* ptr -> [3] struct s */ + BTF_PTR_ENC(3), /* [4] */ + /* ptr -> [6] const int */ + BTF_PTR_ENC(6), /* [5] */ + /* const -> [1] int */ + BTF_CONST_ENC(1), /* [6] */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0a\0b\0c\0int\0next\0s"), + }, + .opts = { + .dont_resolve_fwds = false, + }, +}, +{ + .descr = "dedup: all possible kinds (no duplicates)", + .input = { + .raw_types = { + BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 8), /* [1] int */ + BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_ENUM, 0, 2), 4), /* [2] enum */ + BTF_ENUM_ENC(NAME_TBD, 0), + BTF_ENUM_ENC(NAME_TBD, 1), + BTF_FWD_ENC(NAME_TBD, 1 /* union kind_flag */), /* [3] fwd */ + BTF_TYPE_ARRAY_ENC(2, 1, 7), /* [4] array */ + BTF_STRUCT_ENC(NAME_TBD, 1, 4), /* [5] struct */ + BTF_MEMBER_ENC(NAME_TBD, 1, 0), + BTF_UNION_ENC(NAME_TBD, 1, 4), /* [6] union */ + BTF_MEMBER_ENC(NAME_TBD, 1, 0), + BTF_TYPEDEF_ENC(NAME_TBD, 1), /* [7] typedef */ + BTF_PTR_ENC(0), /* [8] ptr */ + BTF_CONST_ENC(8), /* [9] const */ + BTF_VOLATILE_ENC(8), /* [10] volatile */ + BTF_RESTRICT_ENC(8), /* [11] restrict */ + BTF_FUNC_PROTO_ENC(1, 2), /* [12] func_proto */ + BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1), + BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 8), + BTF_FUNC_ENC(NAME_TBD, 12), /* [13] func */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0A\0B\0C\0D\0E\0F\0G\0H\0I\0J\0K\0L\0M"), + }, + .expect = { + .raw_types = { + BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 8), /* [1] int */ + BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_ENUM, 0, 2), 4), /* [2] enum */ + BTF_ENUM_ENC(NAME_TBD, 0), + BTF_ENUM_ENC(NAME_TBD, 1), + BTF_FWD_ENC(NAME_TBD, 1 /* union kind_flag */), /* [3] fwd */ + BTF_TYPE_ARRAY_ENC(2, 1, 7), /* [4] array */ + BTF_STRUCT_ENC(NAME_TBD, 1, 4), /* [5] struct */ + BTF_MEMBER_ENC(NAME_TBD, 1, 0), + BTF_UNION_ENC(NAME_TBD, 1, 4), /* [6] union */ + BTF_MEMBER_ENC(NAME_TBD, 1, 0), + BTF_TYPEDEF_ENC(NAME_TBD, 1), /* [7] typedef */ + BTF_PTR_ENC(0), /* [8] ptr */ + BTF_CONST_ENC(8), /* [9] const */ + BTF_VOLATILE_ENC(8), /* [10] volatile */ + BTF_RESTRICT_ENC(8), /* [11] restrict */ + BTF_FUNC_PROTO_ENC(1, 2), /* [12] func_proto */ + BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1), + BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 8), + BTF_FUNC_ENC(NAME_TBD, 12), /* [13] func */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0A\0B\0C\0D\0E\0F\0G\0H\0I\0J\0K\0L\0M"), + }, + .opts = { + .dont_resolve_fwds = false, + }, +}, +{ + .descr = "dedup: no int duplicates", + .input = { + .raw_types = { + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 8), + /* different name */ + BTF_TYPE_INT_ENC(NAME_NTH(2), BTF_INT_SIGNED, 0, 32, 8), + /* different encoding */ + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_CHAR, 0, 32, 8), + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_BOOL, 0, 32, 8), + /* different bit offset */ + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 8, 32, 8), + /* different bit size */ + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 27, 8), + /* different byte size */ + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4), + BTF_END_RAW, + }, + BTF_STR_SEC("\0int\0some other int"), + }, + .expect = { + .raw_types = { + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 8), + /* different name */ + BTF_TYPE_INT_ENC(NAME_NTH(2), BTF_INT_SIGNED, 0, 32, 8), + /* different encoding */ + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_CHAR, 0, 32, 8), + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_BOOL, 0, 32, 8), + /* different bit offset */ + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 8, 32, 8), + /* different bit size */ + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 27, 8), + /* different byte size */ + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4), + BTF_END_RAW, + }, + BTF_STR_SEC("\0int\0some other int"), + }, + .opts = { + .dont_resolve_fwds = false, + }, +}, + +}; + +static int btf_type_size(const struct btf_type *t) +{ + int base_size = sizeof(struct btf_type); + __u16 vlen = BTF_INFO_VLEN(t->info); + __u16 kind = BTF_INFO_KIND(t->info); + + switch (kind) { + case BTF_KIND_FWD: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + return base_size; + case BTF_KIND_INT: + return base_size + sizeof(__u32); + case BTF_KIND_ENUM: + return base_size + vlen * sizeof(struct btf_enum); + case BTF_KIND_ARRAY: + return base_size + sizeof(struct btf_array); + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + return base_size + vlen * sizeof(struct btf_member); + case BTF_KIND_FUNC_PROTO: + return base_size + vlen * sizeof(struct btf_param); + default: + fprintf(stderr, "Unsupported BTF_KIND:%u\n", kind); + return -EINVAL; + } +} + +static void dump_btf_strings(const char *strs, __u32 len) +{ + const char *cur = strs; + int i = 0; + + while (cur < strs + len) { + fprintf(stderr, "string #%d: '%s'\n", i, cur); + cur += strlen(cur) + 1; + i++; + } +} + +static int do_test_dedup(unsigned int test_num) +{ + const struct btf_dedup_test *test = &dedup_tests[test_num - 1]; + int err = 0, i; + __u32 test_nr_types, expect_nr_types, test_str_len, expect_str_len; + void *raw_btf; + unsigned int raw_btf_size; + struct btf *test_btf = NULL, *expect_btf = NULL; + const char *ret_test_next_str, *ret_expect_next_str; + const char *test_strs, *expect_strs; + const char *test_str_cur, *test_str_end; + const char *expect_str_cur, *expect_str_end; + + fprintf(stderr, "BTF dedup test[%u] (%s):", test_num, test->descr); + + raw_btf = btf_raw_create(&hdr_tmpl, test->input.raw_types, + test->input.str_sec, test->input.str_sec_size, + &raw_btf_size, &ret_test_next_str); + if (!raw_btf) + return -1; + test_btf = btf__new((__u8 *)raw_btf, raw_btf_size); + free(raw_btf); + if (CHECK(IS_ERR(test_btf), "invalid test_btf errno:%ld", + PTR_ERR(test_btf))) { + err = -1; + goto done; + } + + raw_btf = btf_raw_create(&hdr_tmpl, test->expect.raw_types, + test->expect.str_sec, + test->expect.str_sec_size, + &raw_btf_size, &ret_expect_next_str); + if (!raw_btf) + return -1; + expect_btf = btf__new((__u8 *)raw_btf, raw_btf_size); + free(raw_btf); + if (CHECK(IS_ERR(expect_btf), "invalid expect_btf errno:%ld", + PTR_ERR(expect_btf))) { + err = -1; + goto done; + } + + err = btf__dedup(test_btf, NULL, &test->opts); + if (CHECK(err, "btf_dedup failed errno:%d", err)) { + err = -1; + goto done; + } + + btf__get_strings(test_btf, &test_strs, &test_str_len); + btf__get_strings(expect_btf, &expect_strs, &expect_str_len); + if (CHECK(test_str_len != expect_str_len, + "test_str_len:%u != expect_str_len:%u", + test_str_len, expect_str_len)) { + fprintf(stderr, "\ntest strings:\n"); + dump_btf_strings(test_strs, test_str_len); + fprintf(stderr, "\nexpected strings:\n"); + dump_btf_strings(expect_strs, expect_str_len); + err = -1; + goto done; + } + + test_str_cur = test_strs; + test_str_end = test_strs + test_str_len; + expect_str_cur = expect_strs; + expect_str_end = expect_strs + expect_str_len; + while (test_str_cur < test_str_end && expect_str_cur < expect_str_end) { + size_t test_len, expect_len; + + test_len = strlen(test_str_cur); + expect_len = strlen(expect_str_cur); + if (CHECK(test_len != expect_len, + "test_len:%zu != expect_len:%zu " + "(test_str:%s, expect_str:%s)", + test_len, expect_len, test_str_cur, expect_str_cur)) { + err = -1; + goto done; + } + if (CHECK(strcmp(test_str_cur, expect_str_cur), + "test_str:%s != expect_str:%s", + test_str_cur, expect_str_cur)) { + err = -1; + goto done; + } + test_str_cur += test_len + 1; + expect_str_cur += expect_len + 1; + } + if (CHECK(test_str_cur != test_str_end, + "test_str_cur:%p != test_str_end:%p", + test_str_cur, test_str_end)) { + err = -1; + goto done; + } + + test_nr_types = btf__get_nr_types(test_btf); + expect_nr_types = btf__get_nr_types(expect_btf); + if (CHECK(test_nr_types != expect_nr_types, + "test_nr_types:%u != expect_nr_types:%u", + test_nr_types, expect_nr_types)) { + err = -1; + goto done; + } + + for (i = 1; i <= test_nr_types; i++) { + const struct btf_type *test_type, *expect_type; + int test_size, expect_size; + + test_type = btf__type_by_id(test_btf, i); + expect_type = btf__type_by_id(expect_btf, i); + test_size = btf_type_size(test_type); + expect_size = btf_type_size(expect_type); + + if (CHECK(test_size != expect_size, + "type #%d: test_size:%d != expect_size:%u", + i, test_size, expect_size)) { + err = -1; + goto done; + } + if (CHECK(memcmp((void *)test_type, + (void *)expect_type, + test_size), + "type #%d: contents differ", i)) { + err = -1; + goto done; + } + } + +done: + if (!err) + fprintf(stderr, "OK"); + if (!IS_ERR(test_btf)) + btf__free(test_btf); + if (!IS_ERR(expect_btf)) + btf__free(expect_btf); + + return err; +} + +static int test_dedup(void) +{ + unsigned int i; + int err = 0; + + if (args.dedup_test_num) + return count_result(do_test_dedup(args.dedup_test_num)); + + for (i = 1; i <= ARRAY_SIZE(dedup_tests); i++) + err |= count_result(do_test_dedup(i)); + + return err; +} + static void usage(const char *cmd) { fprintf(stderr, "Usage: %s [-l] [[-r btf_raw_test_num (1 - %zu)] |\n" "\t[-g btf_get_info_test_num (1 - %zu)] |\n" "\t[-f btf_file_test_num (1 - %zu)] |\n" "\t[-k btf_prog_info_raw_test_num (1 - %zu)] |\n" - "\t[-p (pretty print test)]]\n", + "\t[-p (pretty print test)] |\n" + "\t[-d btf_dedup_test_num (1 - %zu)]]\n", cmd, ARRAY_SIZE(raw_tests), ARRAY_SIZE(get_info_tests), - ARRAY_SIZE(file_tests), ARRAY_SIZE(info_raw_tests)); + ARRAY_SIZE(file_tests), ARRAY_SIZE(info_raw_tests), + ARRAY_SIZE(dedup_tests)); } static int parse_args(int argc, char **argv) { - const char *optstr = "lpk:f:r:g:"; + const char *optstr = "hlpk:f:r:g:d:"; int opt; while ((opt = getopt(argc, argv, optstr)) != -1) { @@ -5583,12 +6072,16 @@ static int parse_args(int argc, char **argv) args.info_raw_test_num = atoi(optarg); args.info_raw_test = true; break; + case 'd': + args.dedup_test_num = atoi(optarg); + args.dedup_test = true; + break; case 'h': usage(argv[0]); exit(0); default: - usage(argv[0]); - return -1; + usage(argv[0]); + return -1; } } @@ -5624,6 +6117,14 @@ static int parse_args(int argc, char **argv) return -1; } + if (args.dedup_test_num && + (args.dedup_test_num < 1 || + args.dedup_test_num > ARRAY_SIZE(dedup_tests))) { + fprintf(stderr, "BTF dedup test number must be [1 - %zu]\n", + ARRAY_SIZE(dedup_tests)); + return -1; + } + return 0; } @@ -5659,14 +6160,18 @@ int main(int argc, char **argv) if (args.info_raw_test) err |= test_info_raw(); + if (args.dedup_test) + err |= test_dedup(); + if (args.raw_test || args.get_info_test || args.file_test || - args.pprint_test || args.info_raw_test) + args.pprint_test || args.info_raw_test || args.dedup_test) goto done; err |= test_raw(); err |= test_get_info(); err |= test_file(); err |= test_info_raw(); + err |= test_dedup(); done: print_summary(); |