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- // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
- /*
- * BTF-to-C type converter.
- *
- * Copyright (c) 2019 Facebook
- */
- #include <stdbool.h>
- #include <stddef.h>
- #include <stdlib.h>
- #include <string.h>
- #include <ctype.h>
- #include <endian.h>
- #include <errno.h>
- #include <linux/err.h>
- #include <linux/btf.h>
- #include <linux/kernel.h>
- #include "btf.h"
- #include "hashmap.h"
- #include "libbpf.h"
- #include "libbpf_internal.h"
- static const char PREFIXES[] = "\t\t\t\t\t\t\t\t\t\t\t\t\t";
- static const size_t PREFIX_CNT = sizeof(PREFIXES) - 1;
- static const char *pfx(int lvl)
- {
- return lvl >= PREFIX_CNT ? PREFIXES : &PREFIXES[PREFIX_CNT - lvl];
- }
- enum btf_dump_type_order_state {
- NOT_ORDERED,
- ORDERING,
- ORDERED,
- };
- enum btf_dump_type_emit_state {
- NOT_EMITTED,
- EMITTING,
- EMITTED,
- };
- /* per-type auxiliary state */
- struct btf_dump_type_aux_state {
- /* topological sorting state */
- enum btf_dump_type_order_state order_state: 2;
- /* emitting state used to determine the need for forward declaration */
- enum btf_dump_type_emit_state emit_state: 2;
- /* whether forward declaration was already emitted */
- __u8 fwd_emitted: 1;
- /* whether unique non-duplicate name was already assigned */
- __u8 name_resolved: 1;
- /* whether type is referenced from any other type */
- __u8 referenced: 1;
- };
- /* indent string length; one indent string is added for each indent level */
- #define BTF_DATA_INDENT_STR_LEN 32
- /*
- * Common internal data for BTF type data dump operations.
- */
- struct btf_dump_data {
- const void *data_end; /* end of valid data to show */
- bool compact;
- bool skip_names;
- bool emit_zeroes;
- __u8 indent_lvl; /* base indent level */
- char indent_str[BTF_DATA_INDENT_STR_LEN];
- /* below are used during iteration */
- int depth;
- bool is_array_member;
- bool is_array_terminated;
- bool is_array_char;
- };
- struct btf_dump {
- const struct btf *btf;
- btf_dump_printf_fn_t printf_fn;
- void *cb_ctx;
- int ptr_sz;
- bool strip_mods;
- bool skip_anon_defs;
- int last_id;
- /* per-type auxiliary state */
- struct btf_dump_type_aux_state *type_states;
- size_t type_states_cap;
- /* per-type optional cached unique name, must be freed, if present */
- const char **cached_names;
- size_t cached_names_cap;
- /* topo-sorted list of dependent type definitions */
- __u32 *emit_queue;
- int emit_queue_cap;
- int emit_queue_cnt;
- /*
- * stack of type declarations (e.g., chain of modifiers, arrays,
- * funcs, etc)
- */
- __u32 *decl_stack;
- int decl_stack_cap;
- int decl_stack_cnt;
- /* maps struct/union/enum name to a number of name occurrences */
- struct hashmap *type_names;
- /*
- * maps typedef identifiers and enum value names to a number of such
- * name occurrences
- */
- struct hashmap *ident_names;
- /*
- * data for typed display; allocated if needed.
- */
- struct btf_dump_data *typed_dump;
- };
- static size_t str_hash_fn(const void *key, void *ctx)
- {
- return str_hash(key);
- }
- static bool str_equal_fn(const void *a, const void *b, void *ctx)
- {
- return strcmp(a, b) == 0;
- }
- static const char *btf_name_of(const struct btf_dump *d, __u32 name_off)
- {
- return btf__name_by_offset(d->btf, name_off);
- }
- static void btf_dump_printf(const struct btf_dump *d, const char *fmt, ...)
- {
- va_list args;
- va_start(args, fmt);
- d->printf_fn(d->cb_ctx, fmt, args);
- va_end(args);
- }
- static int btf_dump_mark_referenced(struct btf_dump *d);
- static int btf_dump_resize(struct btf_dump *d);
- struct btf_dump *btf_dump__new(const struct btf *btf,
- btf_dump_printf_fn_t printf_fn,
- void *ctx,
- const struct btf_dump_opts *opts)
- {
- struct btf_dump *d;
- int err;
- if (!OPTS_VALID(opts, btf_dump_opts))
- return libbpf_err_ptr(-EINVAL);
- if (!printf_fn)
- return libbpf_err_ptr(-EINVAL);
- d = calloc(1, sizeof(struct btf_dump));
- if (!d)
- return libbpf_err_ptr(-ENOMEM);
- d->btf = btf;
- d->printf_fn = printf_fn;
- d->cb_ctx = ctx;
- d->ptr_sz = btf__pointer_size(btf) ? : sizeof(void *);
- d->type_names = hashmap__new(str_hash_fn, str_equal_fn, NULL);
- if (IS_ERR(d->type_names)) {
- err = PTR_ERR(d->type_names);
- d->type_names = NULL;
- goto err;
- }
- d->ident_names = hashmap__new(str_hash_fn, str_equal_fn, NULL);
- if (IS_ERR(d->ident_names)) {
- err = PTR_ERR(d->ident_names);
- d->ident_names = NULL;
- goto err;
- }
- err = btf_dump_resize(d);
- if (err)
- goto err;
- return d;
- err:
- btf_dump__free(d);
- return libbpf_err_ptr(err);
- }
- static int btf_dump_resize(struct btf_dump *d)
- {
- int err, last_id = btf__type_cnt(d->btf) - 1;
- if (last_id <= d->last_id)
- return 0;
- if (libbpf_ensure_mem((void **)&d->type_states, &d->type_states_cap,
- sizeof(*d->type_states), last_id + 1))
- return -ENOMEM;
- if (libbpf_ensure_mem((void **)&d->cached_names, &d->cached_names_cap,
- sizeof(*d->cached_names), last_id + 1))
- return -ENOMEM;
- if (d->last_id == 0) {
- /* VOID is special */
- d->type_states[0].order_state = ORDERED;
- d->type_states[0].emit_state = EMITTED;
- }
- /* eagerly determine referenced types for anon enums */
- err = btf_dump_mark_referenced(d);
- if (err)
- return err;
- d->last_id = last_id;
- return 0;
- }
- static void btf_dump_free_names(struct hashmap *map)
- {
- size_t bkt;
- struct hashmap_entry *cur;
- hashmap__for_each_entry(map, cur, bkt)
- free((void *)cur->key);
- hashmap__free(map);
- }
- void btf_dump__free(struct btf_dump *d)
- {
- int i;
- if (IS_ERR_OR_NULL(d))
- return;
- free(d->type_states);
- if (d->cached_names) {
- /* any set cached name is owned by us and should be freed */
- for (i = 0; i <= d->last_id; i++) {
- if (d->cached_names[i])
- free((void *)d->cached_names[i]);
- }
- }
- free(d->cached_names);
- free(d->emit_queue);
- free(d->decl_stack);
- btf_dump_free_names(d->type_names);
- btf_dump_free_names(d->ident_names);
- free(d);
- }
- static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr);
- static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id);
- /*
- * Dump BTF type in a compilable C syntax, including all the necessary
- * dependent types, necessary for compilation. If some of the dependent types
- * were already emitted as part of previous btf_dump__dump_type() invocation
- * for another type, they won't be emitted again. This API allows callers to
- * filter out BTF types according to user-defined criterias and emitted only
- * minimal subset of types, necessary to compile everything. Full struct/union
- * definitions will still be emitted, even if the only usage is through
- * pointer and could be satisfied with just a forward declaration.
- *
- * Dumping is done in two high-level passes:
- * 1. Topologically sort type definitions to satisfy C rules of compilation.
- * 2. Emit type definitions in C syntax.
- *
- * Returns 0 on success; <0, otherwise.
- */
- int btf_dump__dump_type(struct btf_dump *d, __u32 id)
- {
- int err, i;
- if (id >= btf__type_cnt(d->btf))
- return libbpf_err(-EINVAL);
- err = btf_dump_resize(d);
- if (err)
- return libbpf_err(err);
- d->emit_queue_cnt = 0;
- err = btf_dump_order_type(d, id, false);
- if (err < 0)
- return libbpf_err(err);
- for (i = 0; i < d->emit_queue_cnt; i++)
- btf_dump_emit_type(d, d->emit_queue[i], 0 /*top-level*/);
- return 0;
- }
- /*
- * Mark all types that are referenced from any other type. This is used to
- * determine top-level anonymous enums that need to be emitted as an
- * independent type declarations.
- * Anonymous enums come in two flavors: either embedded in a struct's field
- * definition, in which case they have to be declared inline as part of field
- * type declaration; or as a top-level anonymous enum, typically used for
- * declaring global constants. It's impossible to distinguish between two
- * without knowning whether given enum type was referenced from other type:
- * top-level anonymous enum won't be referenced by anything, while embedded
- * one will.
- */
- static int btf_dump_mark_referenced(struct btf_dump *d)
- {
- int i, j, n = btf__type_cnt(d->btf);
- const struct btf_type *t;
- __u16 vlen;
- for (i = d->last_id + 1; i < n; i++) {
- t = btf__type_by_id(d->btf, i);
- vlen = btf_vlen(t);
- switch (btf_kind(t)) {
- case BTF_KIND_INT:
- case BTF_KIND_ENUM:
- case BTF_KIND_ENUM64:
- case BTF_KIND_FWD:
- case BTF_KIND_FLOAT:
- break;
- case BTF_KIND_VOLATILE:
- case BTF_KIND_CONST:
- case BTF_KIND_RESTRICT:
- case BTF_KIND_PTR:
- case BTF_KIND_TYPEDEF:
- case BTF_KIND_FUNC:
- case BTF_KIND_VAR:
- case BTF_KIND_DECL_TAG:
- case BTF_KIND_TYPE_TAG:
- d->type_states[t->type].referenced = 1;
- break;
- case BTF_KIND_ARRAY: {
- const struct btf_array *a = btf_array(t);
- d->type_states[a->index_type].referenced = 1;
- d->type_states[a->type].referenced = 1;
- break;
- }
- case BTF_KIND_STRUCT:
- case BTF_KIND_UNION: {
- const struct btf_member *m = btf_members(t);
- for (j = 0; j < vlen; j++, m++)
- d->type_states[m->type].referenced = 1;
- break;
- }
- case BTF_KIND_FUNC_PROTO: {
- const struct btf_param *p = btf_params(t);
- for (j = 0; j < vlen; j++, p++)
- d->type_states[p->type].referenced = 1;
- break;
- }
- case BTF_KIND_DATASEC: {
- const struct btf_var_secinfo *v = btf_var_secinfos(t);
- for (j = 0; j < vlen; j++, v++)
- d->type_states[v->type].referenced = 1;
- break;
- }
- default:
- return -EINVAL;
- }
- }
- return 0;
- }
- static int btf_dump_add_emit_queue_id(struct btf_dump *d, __u32 id)
- {
- __u32 *new_queue;
- size_t new_cap;
- if (d->emit_queue_cnt >= d->emit_queue_cap) {
- new_cap = max(16, d->emit_queue_cap * 3 / 2);
- new_queue = libbpf_reallocarray(d->emit_queue, new_cap, sizeof(new_queue[0]));
- if (!new_queue)
- return -ENOMEM;
- d->emit_queue = new_queue;
- d->emit_queue_cap = new_cap;
- }
- d->emit_queue[d->emit_queue_cnt++] = id;
- return 0;
- }
- /*
- * Determine order of emitting dependent types and specified type to satisfy
- * C compilation rules. This is done through topological sorting with an
- * additional complication which comes from C rules. The main idea for C is
- * that if some type is "embedded" into a struct/union, it's size needs to be
- * known at the time of definition of containing type. E.g., for:
- *
- * struct A {};
- * struct B { struct A x; }
- *
- * struct A *HAS* to be defined before struct B, because it's "embedded",
- * i.e., it is part of struct B layout. But in the following case:
- *
- * struct A;
- * struct B { struct A *x; }
- * struct A {};
- *
- * it's enough to just have a forward declaration of struct A at the time of
- * struct B definition, as struct B has a pointer to struct A, so the size of
- * field x is known without knowing struct A size: it's sizeof(void *).
- *
- * Unfortunately, there are some trickier cases we need to handle, e.g.:
- *
- * struct A {}; // if this was forward-declaration: compilation error
- * struct B {
- * struct { // anonymous struct
- * struct A y;
- * } *x;
- * };
- *
- * In this case, struct B's field x is a pointer, so it's size is known
- * regardless of the size of (anonymous) struct it points to. But because this
- * struct is anonymous and thus defined inline inside struct B, *and* it
- * embeds struct A, compiler requires full definition of struct A to be known
- * before struct B can be defined. This creates a transitive dependency
- * between struct A and struct B. If struct A was forward-declared before
- * struct B definition and fully defined after struct B definition, that would
- * trigger compilation error.
- *
- * All this means that while we are doing topological sorting on BTF type
- * graph, we need to determine relationships between different types (graph
- * nodes):
- * - weak link (relationship) between X and Y, if Y *CAN* be
- * forward-declared at the point of X definition;
- * - strong link, if Y *HAS* to be fully-defined before X can be defined.
- *
- * The rule is as follows. Given a chain of BTF types from X to Y, if there is
- * BTF_KIND_PTR type in the chain and at least one non-anonymous type
- * Z (excluding X, including Y), then link is weak. Otherwise, it's strong.
- * Weak/strong relationship is determined recursively during DFS traversal and
- * is returned as a result from btf_dump_order_type().
- *
- * btf_dump_order_type() is trying to avoid unnecessary forward declarations,
- * but it is not guaranteeing that no extraneous forward declarations will be
- * emitted.
- *
- * To avoid extra work, algorithm marks some of BTF types as ORDERED, when
- * it's done with them, but not for all (e.g., VOLATILE, CONST, RESTRICT,
- * ARRAY, FUNC_PROTO), as weak/strong semantics for those depends on the
- * entire graph path, so depending where from one came to that BTF type, it
- * might cause weak or strong ordering. For types like STRUCT/UNION/INT/ENUM,
- * once they are processed, there is no need to do it again, so they are
- * marked as ORDERED. We can mark PTR as ORDERED as well, as it semi-forces
- * weak link, unless subsequent referenced STRUCT/UNION/ENUM is anonymous. But
- * in any case, once those are processed, no need to do it again, as the
- * result won't change.
- *
- * Returns:
- * - 1, if type is part of strong link (so there is strong topological
- * ordering requirements);
- * - 0, if type is part of weak link (so can be satisfied through forward
- * declaration);
- * - <0, on error (e.g., unsatisfiable type loop detected).
- */
- static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr)
- {
- /*
- * Order state is used to detect strong link cycles, but only for BTF
- * kinds that are or could be an independent definition (i.e.,
- * stand-alone fwd decl, enum, typedef, struct, union). Ptrs, arrays,
- * func_protos, modifiers are just means to get to these definitions.
- * Int/void don't need definitions, they are assumed to be always
- * properly defined. We also ignore datasec, var, and funcs for now.
- * So for all non-defining kinds, we never even set ordering state,
- * for defining kinds we set ORDERING and subsequently ORDERED if it
- * forms a strong link.
- */
- struct btf_dump_type_aux_state *tstate = &d->type_states[id];
- const struct btf_type *t;
- __u16 vlen;
- int err, i;
- /* return true, letting typedefs know that it's ok to be emitted */
- if (tstate->order_state == ORDERED)
- return 1;
- t = btf__type_by_id(d->btf, id);
- if (tstate->order_state == ORDERING) {
- /* type loop, but resolvable through fwd declaration */
- if (btf_is_composite(t) && through_ptr && t->name_off != 0)
- return 0;
- pr_warn("unsatisfiable type cycle, id:[%u]\n", id);
- return -ELOOP;
- }
- switch (btf_kind(t)) {
- case BTF_KIND_INT:
- case BTF_KIND_FLOAT:
- tstate->order_state = ORDERED;
- return 0;
- case BTF_KIND_PTR:
- err = btf_dump_order_type(d, t->type, true);
- tstate->order_state = ORDERED;
- return err;
- case BTF_KIND_ARRAY:
- return btf_dump_order_type(d, btf_array(t)->type, false);
- case BTF_KIND_STRUCT:
- case BTF_KIND_UNION: {
- const struct btf_member *m = btf_members(t);
- /*
- * struct/union is part of strong link, only if it's embedded
- * (so no ptr in a path) or it's anonymous (so has to be
- * defined inline, even if declared through ptr)
- */
- if (through_ptr && t->name_off != 0)
- return 0;
- tstate->order_state = ORDERING;
- vlen = btf_vlen(t);
- for (i = 0; i < vlen; i++, m++) {
- err = btf_dump_order_type(d, m->type, false);
- if (err < 0)
- return err;
- }
- if (t->name_off != 0) {
- err = btf_dump_add_emit_queue_id(d, id);
- if (err < 0)
- return err;
- }
- tstate->order_state = ORDERED;
- return 1;
- }
- case BTF_KIND_ENUM:
- case BTF_KIND_ENUM64:
- case BTF_KIND_FWD:
- /*
- * non-anonymous or non-referenced enums are top-level
- * declarations and should be emitted. Same logic can be
- * applied to FWDs, it won't hurt anyways.
- */
- if (t->name_off != 0 || !tstate->referenced) {
- err = btf_dump_add_emit_queue_id(d, id);
- if (err)
- return err;
- }
- tstate->order_state = ORDERED;
- return 1;
- case BTF_KIND_TYPEDEF: {
- int is_strong;
- is_strong = btf_dump_order_type(d, t->type, through_ptr);
- if (is_strong < 0)
- return is_strong;
- /* typedef is similar to struct/union w.r.t. fwd-decls */
- if (through_ptr && !is_strong)
- return 0;
- /* typedef is always a named definition */
- err = btf_dump_add_emit_queue_id(d, id);
- if (err)
- return err;
- d->type_states[id].order_state = ORDERED;
- return 1;
- }
- case BTF_KIND_VOLATILE:
- case BTF_KIND_CONST:
- case BTF_KIND_RESTRICT:
- case BTF_KIND_TYPE_TAG:
- return btf_dump_order_type(d, t->type, through_ptr);
- case BTF_KIND_FUNC_PROTO: {
- const struct btf_param *p = btf_params(t);
- bool is_strong;
- err = btf_dump_order_type(d, t->type, through_ptr);
- if (err < 0)
- return err;
- is_strong = err > 0;
- vlen = btf_vlen(t);
- for (i = 0; i < vlen; i++, p++) {
- err = btf_dump_order_type(d, p->type, through_ptr);
- if (err < 0)
- return err;
- if (err > 0)
- is_strong = true;
- }
- return is_strong;
- }
- case BTF_KIND_FUNC:
- case BTF_KIND_VAR:
- case BTF_KIND_DATASEC:
- case BTF_KIND_DECL_TAG:
- d->type_states[id].order_state = ORDERED;
- return 0;
- default:
- return -EINVAL;
- }
- }
- static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id,
- const struct btf_type *t);
- static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id,
- const struct btf_type *t);
- static void btf_dump_emit_struct_def(struct btf_dump *d, __u32 id,
- const struct btf_type *t, int lvl);
- static void btf_dump_emit_enum_fwd(struct btf_dump *d, __u32 id,
- const struct btf_type *t);
- static void btf_dump_emit_enum_def(struct btf_dump *d, __u32 id,
- const struct btf_type *t, int lvl);
- static void btf_dump_emit_fwd_def(struct btf_dump *d, __u32 id,
- const struct btf_type *t);
- static void btf_dump_emit_typedef_def(struct btf_dump *d, __u32 id,
- const struct btf_type *t, int lvl);
- /* a local view into a shared stack */
- struct id_stack {
- const __u32 *ids;
- int cnt;
- };
- static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id,
- const char *fname, int lvl);
- static void btf_dump_emit_type_chain(struct btf_dump *d,
- struct id_stack *decl_stack,
- const char *fname, int lvl);
- static const char *btf_dump_type_name(struct btf_dump *d, __u32 id);
- static const char *btf_dump_ident_name(struct btf_dump *d, __u32 id);
- static size_t btf_dump_name_dups(struct btf_dump *d, struct hashmap *name_map,
- const char *orig_name);
- static bool btf_dump_is_blacklisted(struct btf_dump *d, __u32 id)
- {
- const struct btf_type *t = btf__type_by_id(d->btf, id);
- /* __builtin_va_list is a compiler built-in, which causes compilation
- * errors, when compiling w/ different compiler, then used to compile
- * original code (e.g., GCC to compile kernel, Clang to use generated
- * C header from BTF). As it is built-in, it should be already defined
- * properly internally in compiler.
- */
- if (t->name_off == 0)
- return false;
- return strcmp(btf_name_of(d, t->name_off), "__builtin_va_list") == 0;
- }
- /*
- * Emit C-syntax definitions of types from chains of BTF types.
- *
- * High-level handling of determining necessary forward declarations are handled
- * by btf_dump_emit_type() itself, but all nitty-gritty details of emitting type
- * declarations/definitions in C syntax are handled by a combo of
- * btf_dump_emit_type_decl()/btf_dump_emit_type_chain() w/ delegation to
- * corresponding btf_dump_emit_*_{def,fwd}() functions.
- *
- * We also keep track of "containing struct/union type ID" to determine when
- * we reference it from inside and thus can avoid emitting unnecessary forward
- * declaration.
- *
- * This algorithm is designed in such a way, that even if some error occurs
- * (either technical, e.g., out of memory, or logical, i.e., malformed BTF
- * that doesn't comply to C rules completely), algorithm will try to proceed
- * and produce as much meaningful output as possible.
- */
- static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id)
- {
- struct btf_dump_type_aux_state *tstate = &d->type_states[id];
- bool top_level_def = cont_id == 0;
- const struct btf_type *t;
- __u16 kind;
- if (tstate->emit_state == EMITTED)
- return;
- t = btf__type_by_id(d->btf, id);
- kind = btf_kind(t);
- if (tstate->emit_state == EMITTING) {
- if (tstate->fwd_emitted)
- return;
- switch (kind) {
- case BTF_KIND_STRUCT:
- case BTF_KIND_UNION:
- /*
- * if we are referencing a struct/union that we are
- * part of - then no need for fwd declaration
- */
- if (id == cont_id)
- return;
- if (t->name_off == 0) {
- pr_warn("anonymous struct/union loop, id:[%u]\n",
- id);
- return;
- }
- btf_dump_emit_struct_fwd(d, id, t);
- btf_dump_printf(d, ";\n\n");
- tstate->fwd_emitted = 1;
- break;
- case BTF_KIND_TYPEDEF:
- /*
- * for typedef fwd_emitted means typedef definition
- * was emitted, but it can be used only for "weak"
- * references through pointer only, not for embedding
- */
- if (!btf_dump_is_blacklisted(d, id)) {
- btf_dump_emit_typedef_def(d, id, t, 0);
- btf_dump_printf(d, ";\n\n");
- }
- tstate->fwd_emitted = 1;
- break;
- default:
- break;
- }
- return;
- }
- switch (kind) {
- case BTF_KIND_INT:
- /* Emit type alias definitions if necessary */
- btf_dump_emit_missing_aliases(d, id, t);
- tstate->emit_state = EMITTED;
- break;
- case BTF_KIND_ENUM:
- case BTF_KIND_ENUM64:
- if (top_level_def) {
- btf_dump_emit_enum_def(d, id, t, 0);
- btf_dump_printf(d, ";\n\n");
- }
- tstate->emit_state = EMITTED;
- break;
- case BTF_KIND_PTR:
- case BTF_KIND_VOLATILE:
- case BTF_KIND_CONST:
- case BTF_KIND_RESTRICT:
- case BTF_KIND_TYPE_TAG:
- btf_dump_emit_type(d, t->type, cont_id);
- break;
- case BTF_KIND_ARRAY:
- btf_dump_emit_type(d, btf_array(t)->type, cont_id);
- break;
- case BTF_KIND_FWD:
- btf_dump_emit_fwd_def(d, id, t);
- btf_dump_printf(d, ";\n\n");
- tstate->emit_state = EMITTED;
- break;
- case BTF_KIND_TYPEDEF:
- tstate->emit_state = EMITTING;
- btf_dump_emit_type(d, t->type, id);
- /*
- * typedef can server as both definition and forward
- * declaration; at this stage someone depends on
- * typedef as a forward declaration (refers to it
- * through pointer), so unless we already did it,
- * emit typedef as a forward declaration
- */
- if (!tstate->fwd_emitted && !btf_dump_is_blacklisted(d, id)) {
- btf_dump_emit_typedef_def(d, id, t, 0);
- btf_dump_printf(d, ";\n\n");
- }
- tstate->emit_state = EMITTED;
- break;
- case BTF_KIND_STRUCT:
- case BTF_KIND_UNION:
- tstate->emit_state = EMITTING;
- /* if it's a top-level struct/union definition or struct/union
- * is anonymous, then in C we'll be emitting all fields and
- * their types (as opposed to just `struct X`), so we need to
- * make sure that all types, referenced from struct/union
- * members have necessary forward-declarations, where
- * applicable
- */
- if (top_level_def || t->name_off == 0) {
- const struct btf_member *m = btf_members(t);
- __u16 vlen = btf_vlen(t);
- int i, new_cont_id;
- new_cont_id = t->name_off == 0 ? cont_id : id;
- for (i = 0; i < vlen; i++, m++)
- btf_dump_emit_type(d, m->type, new_cont_id);
- } else if (!tstate->fwd_emitted && id != cont_id) {
- btf_dump_emit_struct_fwd(d, id, t);
- btf_dump_printf(d, ";\n\n");
- tstate->fwd_emitted = 1;
- }
- if (top_level_def) {
- btf_dump_emit_struct_def(d, id, t, 0);
- btf_dump_printf(d, ";\n\n");
- tstate->emit_state = EMITTED;
- } else {
- tstate->emit_state = NOT_EMITTED;
- }
- break;
- case BTF_KIND_FUNC_PROTO: {
- const struct btf_param *p = btf_params(t);
- __u16 n = btf_vlen(t);
- int i;
- btf_dump_emit_type(d, t->type, cont_id);
- for (i = 0; i < n; i++, p++)
- btf_dump_emit_type(d, p->type, cont_id);
- break;
- }
- default:
- break;
- }
- }
- static bool btf_is_struct_packed(const struct btf *btf, __u32 id,
- const struct btf_type *t)
- {
- const struct btf_member *m;
- int max_align = 1, align, i, bit_sz;
- __u16 vlen;
- m = btf_members(t);
- vlen = btf_vlen(t);
- /* all non-bitfield fields have to be naturally aligned */
- for (i = 0; i < vlen; i++, m++) {
- align = btf__align_of(btf, m->type);
- bit_sz = btf_member_bitfield_size(t, i);
- if (align && bit_sz == 0 && m->offset % (8 * align) != 0)
- return true;
- max_align = max(align, max_align);
- }
- /* size of a non-packed struct has to be a multiple of its alignment */
- if (t->size % max_align != 0)
- return true;
- /*
- * if original struct was marked as packed, but its layout is
- * naturally aligned, we'll detect that it's not packed
- */
- return false;
- }
- static void btf_dump_emit_bit_padding(const struct btf_dump *d,
- int cur_off, int next_off, int next_align,
- bool in_bitfield, int lvl)
- {
- const struct {
- const char *name;
- int bits;
- } pads[] = {
- {"long", d->ptr_sz * 8}, {"int", 32}, {"short", 16}, {"char", 8}
- };
- int new_off, pad_bits, bits, i;
- const char *pad_type;
- if (cur_off >= next_off)
- return; /* no gap */
- /* For filling out padding we want to take advantage of
- * natural alignment rules to minimize unnecessary explicit
- * padding. First, we find the largest type (among long, int,
- * short, or char) that can be used to force naturally aligned
- * boundary. Once determined, we'll use such type to fill in
- * the remaining padding gap. In some cases we can rely on
- * compiler filling some gaps, but sometimes we need to force
- * alignment to close natural alignment with markers like
- * `long: 0` (this is always the case for bitfields). Note
- * that even if struct itself has, let's say 4-byte alignment
- * (i.e., it only uses up to int-aligned types), using `long:
- * X;` explicit padding doesn't actually change struct's
- * overall alignment requirements, but compiler does take into
- * account that type's (long, in this example) natural
- * alignment requirements when adding implicit padding. We use
- * this fact heavily and don't worry about ruining correct
- * struct alignment requirement.
- */
- for (i = 0; i < ARRAY_SIZE(pads); i++) {
- pad_bits = pads[i].bits;
- pad_type = pads[i].name;
- new_off = roundup(cur_off, pad_bits);
- if (new_off <= next_off)
- break;
- }
- if (new_off > cur_off && new_off <= next_off) {
- /* We need explicit `<type>: 0` aligning mark if next
- * field is right on alignment offset and its
- * alignment requirement is less strict than <type>'s
- * alignment (so compiler won't naturally align to the
- * offset we expect), or if subsequent `<type>: X`,
- * will actually completely fit in the remaining hole,
- * making compiler basically ignore `<type>: X`
- * completely.
- */
- if (in_bitfield ||
- (new_off == next_off && roundup(cur_off, next_align * 8) != new_off) ||
- (new_off != next_off && next_off - new_off <= new_off - cur_off))
- /* but for bitfields we'll emit explicit bit count */
- btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type,
- in_bitfield ? new_off - cur_off : 0);
- cur_off = new_off;
- }
- /* Now we know we start at naturally aligned offset for a chosen
- * padding type (long, int, short, or char), and so the rest is just
- * a straightforward filling of remaining padding gap with full
- * `<type>: sizeof(<type>);` markers, except for the last one, which
- * might need smaller than sizeof(<type>) padding.
- */
- while (cur_off != next_off) {
- bits = min(next_off - cur_off, pad_bits);
- if (bits == pad_bits) {
- btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type, pad_bits);
- cur_off += bits;
- continue;
- }
- /* For the remainder padding that doesn't cover entire
- * pad_type bit length, we pick the smallest necessary type.
- * This is pure aesthetics, we could have just used `long`,
- * but having smallest necessary one communicates better the
- * scale of the padding gap.
- */
- for (i = ARRAY_SIZE(pads) - 1; i >= 0; i--) {
- pad_type = pads[i].name;
- pad_bits = pads[i].bits;
- if (pad_bits < bits)
- continue;
- btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type, bits);
- cur_off += bits;
- break;
- }
- }
- }
- static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id,
- const struct btf_type *t)
- {
- btf_dump_printf(d, "%s%s%s",
- btf_is_struct(t) ? "struct" : "union",
- t->name_off ? " " : "",
- btf_dump_type_name(d, id));
- }
- static void btf_dump_emit_struct_def(struct btf_dump *d,
- __u32 id,
- const struct btf_type *t,
- int lvl)
- {
- const struct btf_member *m = btf_members(t);
- bool is_struct = btf_is_struct(t);
- bool packed, prev_bitfield = false;
- int align, i, off = 0;
- __u16 vlen = btf_vlen(t);
- align = btf__align_of(d->btf, id);
- packed = is_struct ? btf_is_struct_packed(d->btf, id, t) : 0;
- btf_dump_printf(d, "%s%s%s {",
- is_struct ? "struct" : "union",
- t->name_off ? " " : "",
- btf_dump_type_name(d, id));
- for (i = 0; i < vlen; i++, m++) {
- const char *fname;
- int m_off, m_sz, m_align;
- bool in_bitfield;
- fname = btf_name_of(d, m->name_off);
- m_sz = btf_member_bitfield_size(t, i);
- m_off = btf_member_bit_offset(t, i);
- m_align = packed ? 1 : btf__align_of(d->btf, m->type);
- in_bitfield = prev_bitfield && m_sz != 0;
- btf_dump_emit_bit_padding(d, off, m_off, m_align, in_bitfield, lvl + 1);
- btf_dump_printf(d, "\n%s", pfx(lvl + 1));
- btf_dump_emit_type_decl(d, m->type, fname, lvl + 1);
- if (m_sz) {
- btf_dump_printf(d, ": %d", m_sz);
- off = m_off + m_sz;
- prev_bitfield = true;
- } else {
- m_sz = max((__s64)0, btf__resolve_size(d->btf, m->type));
- off = m_off + m_sz * 8;
- prev_bitfield = false;
- }
- btf_dump_printf(d, ";");
- }
- /* pad at the end, if necessary */
- if (is_struct)
- btf_dump_emit_bit_padding(d, off, t->size * 8, align, false, lvl + 1);
- /*
- * Keep `struct empty {}` on a single line,
- * only print newline when there are regular or padding fields.
- */
- if (vlen || t->size) {
- btf_dump_printf(d, "\n");
- btf_dump_printf(d, "%s}", pfx(lvl));
- } else {
- btf_dump_printf(d, "}");
- }
- if (packed)
- btf_dump_printf(d, " __attribute__((packed))");
- }
- static const char *missing_base_types[][2] = {
- /*
- * GCC emits typedefs to its internal __PolyX_t types when compiling Arm
- * SIMD intrinsics. Alias them to standard base types.
- */
- { "__Poly8_t", "unsigned char" },
- { "__Poly16_t", "unsigned short" },
- { "__Poly64_t", "unsigned long long" },
- { "__Poly128_t", "unsigned __int128" },
- };
- static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id,
- const struct btf_type *t)
- {
- const char *name = btf_dump_type_name(d, id);
- int i;
- for (i = 0; i < ARRAY_SIZE(missing_base_types); i++) {
- if (strcmp(name, missing_base_types[i][0]) == 0) {
- btf_dump_printf(d, "typedef %s %s;\n\n",
- missing_base_types[i][1], name);
- break;
- }
- }
- }
- static void btf_dump_emit_enum_fwd(struct btf_dump *d, __u32 id,
- const struct btf_type *t)
- {
- btf_dump_printf(d, "enum %s", btf_dump_type_name(d, id));
- }
- static void btf_dump_emit_enum32_val(struct btf_dump *d,
- const struct btf_type *t,
- int lvl, __u16 vlen)
- {
- const struct btf_enum *v = btf_enum(t);
- bool is_signed = btf_kflag(t);
- const char *fmt_str;
- const char *name;
- size_t dup_cnt;
- int i;
- for (i = 0; i < vlen; i++, v++) {
- name = btf_name_of(d, v->name_off);
- /* enumerators share namespace with typedef idents */
- dup_cnt = btf_dump_name_dups(d, d->ident_names, name);
- if (dup_cnt > 1) {
- fmt_str = is_signed ? "\n%s%s___%zd = %d," : "\n%s%s___%zd = %u,";
- btf_dump_printf(d, fmt_str, pfx(lvl + 1), name, dup_cnt, v->val);
- } else {
- fmt_str = is_signed ? "\n%s%s = %d," : "\n%s%s = %u,";
- btf_dump_printf(d, fmt_str, pfx(lvl + 1), name, v->val);
- }
- }
- }
- static void btf_dump_emit_enum64_val(struct btf_dump *d,
- const struct btf_type *t,
- int lvl, __u16 vlen)
- {
- const struct btf_enum64 *v = btf_enum64(t);
- bool is_signed = btf_kflag(t);
- const char *fmt_str;
- const char *name;
- size_t dup_cnt;
- __u64 val;
- int i;
- for (i = 0; i < vlen; i++, v++) {
- name = btf_name_of(d, v->name_off);
- dup_cnt = btf_dump_name_dups(d, d->ident_names, name);
- val = btf_enum64_value(v);
- if (dup_cnt > 1) {
- fmt_str = is_signed ? "\n%s%s___%zd = %lldLL,"
- : "\n%s%s___%zd = %lluULL,";
- btf_dump_printf(d, fmt_str,
- pfx(lvl + 1), name, dup_cnt,
- (unsigned long long)val);
- } else {
- fmt_str = is_signed ? "\n%s%s = %lldLL,"
- : "\n%s%s = %lluULL,";
- btf_dump_printf(d, fmt_str,
- pfx(lvl + 1), name,
- (unsigned long long)val);
- }
- }
- }
- static void btf_dump_emit_enum_def(struct btf_dump *d, __u32 id,
- const struct btf_type *t,
- int lvl)
- {
- __u16 vlen = btf_vlen(t);
- btf_dump_printf(d, "enum%s%s",
- t->name_off ? " " : "",
- btf_dump_type_name(d, id));
- if (!vlen)
- return;
- btf_dump_printf(d, " {");
- if (btf_is_enum(t))
- btf_dump_emit_enum32_val(d, t, lvl, vlen);
- else
- btf_dump_emit_enum64_val(d, t, lvl, vlen);
- btf_dump_printf(d, "\n%s}", pfx(lvl));
- }
- static void btf_dump_emit_fwd_def(struct btf_dump *d, __u32 id,
- const struct btf_type *t)
- {
- const char *name = btf_dump_type_name(d, id);
- if (btf_kflag(t))
- btf_dump_printf(d, "union %s", name);
- else
- btf_dump_printf(d, "struct %s", name);
- }
- static void btf_dump_emit_typedef_def(struct btf_dump *d, __u32 id,
- const struct btf_type *t, int lvl)
- {
- const char *name = btf_dump_ident_name(d, id);
- /*
- * Old GCC versions are emitting invalid typedef for __gnuc_va_list
- * pointing to VOID. This generates warnings from btf_dump() and
- * results in uncompilable header file, so we are fixing it up here
- * with valid typedef into __builtin_va_list.
- */
- if (t->type == 0 && strcmp(name, "__gnuc_va_list") == 0) {
- btf_dump_printf(d, "typedef __builtin_va_list __gnuc_va_list");
- return;
- }
- btf_dump_printf(d, "typedef ");
- btf_dump_emit_type_decl(d, t->type, name, lvl);
- }
- static int btf_dump_push_decl_stack_id(struct btf_dump *d, __u32 id)
- {
- __u32 *new_stack;
- size_t new_cap;
- if (d->decl_stack_cnt >= d->decl_stack_cap) {
- new_cap = max(16, d->decl_stack_cap * 3 / 2);
- new_stack = libbpf_reallocarray(d->decl_stack, new_cap, sizeof(new_stack[0]));
- if (!new_stack)
- return -ENOMEM;
- d->decl_stack = new_stack;
- d->decl_stack_cap = new_cap;
- }
- d->decl_stack[d->decl_stack_cnt++] = id;
- return 0;
- }
- /*
- * Emit type declaration (e.g., field type declaration in a struct or argument
- * declaration in function prototype) in correct C syntax.
- *
- * For most types it's trivial, but there are few quirky type declaration
- * cases worth mentioning:
- * - function prototypes (especially nesting of function prototypes);
- * - arrays;
- * - const/volatile/restrict for pointers vs other types.
- *
- * For a good discussion of *PARSING* C syntax (as a human), see
- * Peter van der Linden's "Expert C Programming: Deep C Secrets",
- * Ch.3 "Unscrambling Declarations in C".
- *
- * It won't help with BTF to C conversion much, though, as it's an opposite
- * problem. So we came up with this algorithm in reverse to van der Linden's
- * parsing algorithm. It goes from structured BTF representation of type
- * declaration to a valid compilable C syntax.
- *
- * For instance, consider this C typedef:
- * typedef const int * const * arr[10] arr_t;
- * It will be represented in BTF with this chain of BTF types:
- * [typedef] -> [array] -> [ptr] -> [const] -> [ptr] -> [const] -> [int]
- *
- * Notice how [const] modifier always goes before type it modifies in BTF type
- * graph, but in C syntax, const/volatile/restrict modifiers are written to
- * the right of pointers, but to the left of other types. There are also other
- * quirks, like function pointers, arrays of them, functions returning other
- * functions, etc.
- *
- * We handle that by pushing all the types to a stack, until we hit "terminal"
- * type (int/enum/struct/union/fwd). Then depending on the kind of a type on
- * top of a stack, modifiers are handled differently. Array/function pointers
- * have also wildly different syntax and how nesting of them are done. See
- * code for authoritative definition.
- *
- * To avoid allocating new stack for each independent chain of BTF types, we
- * share one bigger stack, with each chain working only on its own local view
- * of a stack frame. Some care is required to "pop" stack frames after
- * processing type declaration chain.
- */
- int btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
- const struct btf_dump_emit_type_decl_opts *opts)
- {
- const char *fname;
- int lvl, err;
- if (!OPTS_VALID(opts, btf_dump_emit_type_decl_opts))
- return libbpf_err(-EINVAL);
- err = btf_dump_resize(d);
- if (err)
- return libbpf_err(err);
- fname = OPTS_GET(opts, field_name, "");
- lvl = OPTS_GET(opts, indent_level, 0);
- d->strip_mods = OPTS_GET(opts, strip_mods, false);
- btf_dump_emit_type_decl(d, id, fname, lvl);
- d->strip_mods = false;
- return 0;
- }
- static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id,
- const char *fname, int lvl)
- {
- struct id_stack decl_stack;
- const struct btf_type *t;
- int err, stack_start;
- stack_start = d->decl_stack_cnt;
- for (;;) {
- t = btf__type_by_id(d->btf, id);
- if (d->strip_mods && btf_is_mod(t))
- goto skip_mod;
- err = btf_dump_push_decl_stack_id(d, id);
- if (err < 0) {
- /*
- * if we don't have enough memory for entire type decl
- * chain, restore stack, emit warning, and try to
- * proceed nevertheless
- */
- pr_warn("not enough memory for decl stack:%d", err);
- d->decl_stack_cnt = stack_start;
- return;
- }
- skip_mod:
- /* VOID */
- if (id == 0)
- break;
- switch (btf_kind(t)) {
- case BTF_KIND_PTR:
- case BTF_KIND_VOLATILE:
- case BTF_KIND_CONST:
- case BTF_KIND_RESTRICT:
- case BTF_KIND_FUNC_PROTO:
- case BTF_KIND_TYPE_TAG:
- id = t->type;
- break;
- case BTF_KIND_ARRAY:
- id = btf_array(t)->type;
- break;
- case BTF_KIND_INT:
- case BTF_KIND_ENUM:
- case BTF_KIND_ENUM64:
- case BTF_KIND_FWD:
- case BTF_KIND_STRUCT:
- case BTF_KIND_UNION:
- case BTF_KIND_TYPEDEF:
- case BTF_KIND_FLOAT:
- goto done;
- default:
- pr_warn("unexpected type in decl chain, kind:%u, id:[%u]\n",
- btf_kind(t), id);
- goto done;
- }
- }
- done:
- /*
- * We might be inside a chain of declarations (e.g., array of function
- * pointers returning anonymous (so inlined) structs, having another
- * array field). Each of those needs its own "stack frame" to handle
- * emitting of declarations. Those stack frames are non-overlapping
- * portions of shared btf_dump->decl_stack. To make it a bit nicer to
- * handle this set of nested stacks, we create a view corresponding to
- * our own "stack frame" and work with it as an independent stack.
- * We'll need to clean up after emit_type_chain() returns, though.
- */
- decl_stack.ids = d->decl_stack + stack_start;
- decl_stack.cnt = d->decl_stack_cnt - stack_start;
- btf_dump_emit_type_chain(d, &decl_stack, fname, lvl);
- /*
- * emit_type_chain() guarantees that it will pop its entire decl_stack
- * frame before returning. But it works with a read-only view into
- * decl_stack, so it doesn't actually pop anything from the
- * perspective of shared btf_dump->decl_stack, per se. We need to
- * reset decl_stack state to how it was before us to avoid it growing
- * all the time.
- */
- d->decl_stack_cnt = stack_start;
- }
- static void btf_dump_emit_mods(struct btf_dump *d, struct id_stack *decl_stack)
- {
- const struct btf_type *t;
- __u32 id;
- while (decl_stack->cnt) {
- id = decl_stack->ids[decl_stack->cnt - 1];
- t = btf__type_by_id(d->btf, id);
- switch (btf_kind(t)) {
- case BTF_KIND_VOLATILE:
- btf_dump_printf(d, "volatile ");
- break;
- case BTF_KIND_CONST:
- btf_dump_printf(d, "const ");
- break;
- case BTF_KIND_RESTRICT:
- btf_dump_printf(d, "restrict ");
- break;
- default:
- return;
- }
- decl_stack->cnt--;
- }
- }
- static void btf_dump_drop_mods(struct btf_dump *d, struct id_stack *decl_stack)
- {
- const struct btf_type *t;
- __u32 id;
- while (decl_stack->cnt) {
- id = decl_stack->ids[decl_stack->cnt - 1];
- t = btf__type_by_id(d->btf, id);
- if (!btf_is_mod(t))
- return;
- decl_stack->cnt--;
- }
- }
- static void btf_dump_emit_name(const struct btf_dump *d,
- const char *name, bool last_was_ptr)
- {
- bool separate = name[0] && !last_was_ptr;
- btf_dump_printf(d, "%s%s", separate ? " " : "", name);
- }
- static void btf_dump_emit_type_chain(struct btf_dump *d,
- struct id_stack *decls,
- const char *fname, int lvl)
- {
- /*
- * last_was_ptr is used to determine if we need to separate pointer
- * asterisk (*) from previous part of type signature with space, so
- * that we get `int ***`, instead of `int * * *`. We default to true
- * for cases where we have single pointer in a chain. E.g., in ptr ->
- * func_proto case. func_proto will start a new emit_type_chain call
- * with just ptr, which should be emitted as (*) or (*<fname>), so we
- * don't want to prepend space for that last pointer.
- */
- bool last_was_ptr = true;
- const struct btf_type *t;
- const char *name;
- __u16 kind;
- __u32 id;
- while (decls->cnt) {
- id = decls->ids[--decls->cnt];
- if (id == 0) {
- /* VOID is a special snowflake */
- btf_dump_emit_mods(d, decls);
- btf_dump_printf(d, "void");
- last_was_ptr = false;
- continue;
- }
- t = btf__type_by_id(d->btf, id);
- kind = btf_kind(t);
- switch (kind) {
- case BTF_KIND_INT:
- case BTF_KIND_FLOAT:
- btf_dump_emit_mods(d, decls);
- name = btf_name_of(d, t->name_off);
- btf_dump_printf(d, "%s", name);
- break;
- case BTF_KIND_STRUCT:
- case BTF_KIND_UNION:
- btf_dump_emit_mods(d, decls);
- /* inline anonymous struct/union */
- if (t->name_off == 0 && !d->skip_anon_defs)
- btf_dump_emit_struct_def(d, id, t, lvl);
- else
- btf_dump_emit_struct_fwd(d, id, t);
- break;
- case BTF_KIND_ENUM:
- case BTF_KIND_ENUM64:
- btf_dump_emit_mods(d, decls);
- /* inline anonymous enum */
- if (t->name_off == 0 && !d->skip_anon_defs)
- btf_dump_emit_enum_def(d, id, t, lvl);
- else
- btf_dump_emit_enum_fwd(d, id, t);
- break;
- case BTF_KIND_FWD:
- btf_dump_emit_mods(d, decls);
- btf_dump_emit_fwd_def(d, id, t);
- break;
- case BTF_KIND_TYPEDEF:
- btf_dump_emit_mods(d, decls);
- btf_dump_printf(d, "%s", btf_dump_ident_name(d, id));
- break;
- case BTF_KIND_PTR:
- btf_dump_printf(d, "%s", last_was_ptr ? "*" : " *");
- break;
- case BTF_KIND_VOLATILE:
- btf_dump_printf(d, " volatile");
- break;
- case BTF_KIND_CONST:
- btf_dump_printf(d, " const");
- break;
- case BTF_KIND_RESTRICT:
- btf_dump_printf(d, " restrict");
- break;
- case BTF_KIND_TYPE_TAG:
- btf_dump_emit_mods(d, decls);
- name = btf_name_of(d, t->name_off);
- btf_dump_printf(d, " __attribute__((btf_type_tag(\"%s\")))", name);
- break;
- case BTF_KIND_ARRAY: {
- const struct btf_array *a = btf_array(t);
- const struct btf_type *next_t;
- __u32 next_id;
- bool multidim;
- /*
- * GCC has a bug
- * (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=8354)
- * which causes it to emit extra const/volatile
- * modifiers for an array, if array's element type has
- * const/volatile modifiers. Clang doesn't do that.
- * In general, it doesn't seem very meaningful to have
- * a const/volatile modifier for array, so we are
- * going to silently skip them here.
- */
- btf_dump_drop_mods(d, decls);
- if (decls->cnt == 0) {
- btf_dump_emit_name(d, fname, last_was_ptr);
- btf_dump_printf(d, "[%u]", a->nelems);
- return;
- }
- next_id = decls->ids[decls->cnt - 1];
- next_t = btf__type_by_id(d->btf, next_id);
- multidim = btf_is_array(next_t);
- /* we need space if we have named non-pointer */
- if (fname[0] && !last_was_ptr)
- btf_dump_printf(d, " ");
- /* no parentheses for multi-dimensional array */
- if (!multidim)
- btf_dump_printf(d, "(");
- btf_dump_emit_type_chain(d, decls, fname, lvl);
- if (!multidim)
- btf_dump_printf(d, ")");
- btf_dump_printf(d, "[%u]", a->nelems);
- return;
- }
- case BTF_KIND_FUNC_PROTO: {
- const struct btf_param *p = btf_params(t);
- __u16 vlen = btf_vlen(t);
- int i;
- /*
- * GCC emits extra volatile qualifier for
- * __attribute__((noreturn)) function pointers. Clang
- * doesn't do it. It's a GCC quirk for backwards
- * compatibility with code written for GCC <2.5. So,
- * similarly to extra qualifiers for array, just drop
- * them, instead of handling them.
- */
- btf_dump_drop_mods(d, decls);
- if (decls->cnt) {
- btf_dump_printf(d, " (");
- btf_dump_emit_type_chain(d, decls, fname, lvl);
- btf_dump_printf(d, ")");
- } else {
- btf_dump_emit_name(d, fname, last_was_ptr);
- }
- btf_dump_printf(d, "(");
- /*
- * Clang for BPF target generates func_proto with no
- * args as a func_proto with a single void arg (e.g.,
- * `int (*f)(void)` vs just `int (*f)()`). We are
- * going to pretend there are no args for such case.
- */
- if (vlen == 1 && p->type == 0) {
- btf_dump_printf(d, ")");
- return;
- }
- for (i = 0; i < vlen; i++, p++) {
- if (i > 0)
- btf_dump_printf(d, ", ");
- /* last arg of type void is vararg */
- if (i == vlen - 1 && p->type == 0) {
- btf_dump_printf(d, "...");
- break;
- }
- name = btf_name_of(d, p->name_off);
- btf_dump_emit_type_decl(d, p->type, name, lvl);
- }
- btf_dump_printf(d, ")");
- return;
- }
- default:
- pr_warn("unexpected type in decl chain, kind:%u, id:[%u]\n",
- kind, id);
- return;
- }
- last_was_ptr = kind == BTF_KIND_PTR;
- }
- btf_dump_emit_name(d, fname, last_was_ptr);
- }
- /* show type name as (type_name) */
- static void btf_dump_emit_type_cast(struct btf_dump *d, __u32 id,
- bool top_level)
- {
- const struct btf_type *t;
- /* for array members, we don't bother emitting type name for each
- * member to avoid the redundancy of
- * .name = (char[4])[(char)'f',(char)'o',(char)'o',]
- */
- if (d->typed_dump->is_array_member)
- return;
- /* avoid type name specification for variable/section; it will be done
- * for the associated variable value(s).
- */
- t = btf__type_by_id(d->btf, id);
- if (btf_is_var(t) || btf_is_datasec(t))
- return;
- if (top_level)
- btf_dump_printf(d, "(");
- d->skip_anon_defs = true;
- d->strip_mods = true;
- btf_dump_emit_type_decl(d, id, "", 0);
- d->strip_mods = false;
- d->skip_anon_defs = false;
- if (top_level)
- btf_dump_printf(d, ")");
- }
- /* return number of duplicates (occurrences) of a given name */
- static size_t btf_dump_name_dups(struct btf_dump *d, struct hashmap *name_map,
- const char *orig_name)
- {
- char *old_name, *new_name;
- size_t dup_cnt = 0;
- int err;
- new_name = strdup(orig_name);
- if (!new_name)
- return 1;
- hashmap__find(name_map, orig_name, (void **)&dup_cnt);
- dup_cnt++;
- err = hashmap__set(name_map, new_name, (void *)dup_cnt,
- (const void **)&old_name, NULL);
- if (err)
- free(new_name);
- free(old_name);
- return dup_cnt;
- }
- static const char *btf_dump_resolve_name(struct btf_dump *d, __u32 id,
- struct hashmap *name_map)
- {
- struct btf_dump_type_aux_state *s = &d->type_states[id];
- const struct btf_type *t = btf__type_by_id(d->btf, id);
- const char *orig_name = btf_name_of(d, t->name_off);
- const char **cached_name = &d->cached_names[id];
- size_t dup_cnt;
- if (t->name_off == 0)
- return "";
- if (s->name_resolved)
- return *cached_name ? *cached_name : orig_name;
- if (btf_is_fwd(t) || (btf_is_enum(t) && btf_vlen(t) == 0)) {
- s->name_resolved = 1;
- return orig_name;
- }
- dup_cnt = btf_dump_name_dups(d, name_map, orig_name);
- if (dup_cnt > 1) {
- const size_t max_len = 256;
- char new_name[max_len];
- snprintf(new_name, max_len, "%s___%zu", orig_name, dup_cnt);
- *cached_name = strdup(new_name);
- }
- s->name_resolved = 1;
- return *cached_name ? *cached_name : orig_name;
- }
- static const char *btf_dump_type_name(struct btf_dump *d, __u32 id)
- {
- return btf_dump_resolve_name(d, id, d->type_names);
- }
- static const char *btf_dump_ident_name(struct btf_dump *d, __u32 id)
- {
- return btf_dump_resolve_name(d, id, d->ident_names);
- }
- static int btf_dump_dump_type_data(struct btf_dump *d,
- const char *fname,
- const struct btf_type *t,
- __u32 id,
- const void *data,
- __u8 bits_offset,
- __u8 bit_sz);
- static const char *btf_dump_data_newline(struct btf_dump *d)
- {
- return d->typed_dump->compact || d->typed_dump->depth == 0 ? "" : "\n";
- }
- static const char *btf_dump_data_delim(struct btf_dump *d)
- {
- return d->typed_dump->depth == 0 ? "" : ",";
- }
- static void btf_dump_data_pfx(struct btf_dump *d)
- {
- int i, lvl = d->typed_dump->indent_lvl + d->typed_dump->depth;
- if (d->typed_dump->compact)
- return;
- for (i = 0; i < lvl; i++)
- btf_dump_printf(d, "%s", d->typed_dump->indent_str);
- }
- /* A macro is used here as btf_type_value[s]() appends format specifiers
- * to the format specifier passed in; these do the work of appending
- * delimiters etc while the caller simply has to specify the type values
- * in the format specifier + value(s).
- */
- #define btf_dump_type_values(d, fmt, ...) \
- btf_dump_printf(d, fmt "%s%s", \
- ##__VA_ARGS__, \
- btf_dump_data_delim(d), \
- btf_dump_data_newline(d))
- static int btf_dump_unsupported_data(struct btf_dump *d,
- const struct btf_type *t,
- __u32 id)
- {
- btf_dump_printf(d, "<unsupported kind:%u>", btf_kind(t));
- return -ENOTSUP;
- }
- static int btf_dump_get_bitfield_value(struct btf_dump *d,
- const struct btf_type *t,
- const void *data,
- __u8 bits_offset,
- __u8 bit_sz,
- __u64 *value)
- {
- __u16 left_shift_bits, right_shift_bits;
- const __u8 *bytes = data;
- __u8 nr_copy_bits;
- __u64 num = 0;
- int i;
- /* Maximum supported bitfield size is 64 bits */
- if (t->size > 8) {
- pr_warn("unexpected bitfield size %d\n", t->size);
- return -EINVAL;
- }
- /* Bitfield value retrieval is done in two steps; first relevant bytes are
- * stored in num, then we left/right shift num to eliminate irrelevant bits.
- */
- #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
- for (i = t->size - 1; i >= 0; i--)
- num = num * 256 + bytes[i];
- nr_copy_bits = bit_sz + bits_offset;
- #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
- for (i = 0; i < t->size; i++)
- num = num * 256 + bytes[i];
- nr_copy_bits = t->size * 8 - bits_offset;
- #else
- # error "Unrecognized __BYTE_ORDER__"
- #endif
- left_shift_bits = 64 - nr_copy_bits;
- right_shift_bits = 64 - bit_sz;
- *value = (num << left_shift_bits) >> right_shift_bits;
- return 0;
- }
- static int btf_dump_bitfield_check_zero(struct btf_dump *d,
- const struct btf_type *t,
- const void *data,
- __u8 bits_offset,
- __u8 bit_sz)
- {
- __u64 check_num;
- int err;
- err = btf_dump_get_bitfield_value(d, t, data, bits_offset, bit_sz, &check_num);
- if (err)
- return err;
- if (check_num == 0)
- return -ENODATA;
- return 0;
- }
- static int btf_dump_bitfield_data(struct btf_dump *d,
- const struct btf_type *t,
- const void *data,
- __u8 bits_offset,
- __u8 bit_sz)
- {
- __u64 print_num;
- int err;
- err = btf_dump_get_bitfield_value(d, t, data, bits_offset, bit_sz, &print_num);
- if (err)
- return err;
- btf_dump_type_values(d, "0x%llx", (unsigned long long)print_num);
- return 0;
- }
- /* ints, floats and ptrs */
- static int btf_dump_base_type_check_zero(struct btf_dump *d,
- const struct btf_type *t,
- __u32 id,
- const void *data)
- {
- static __u8 bytecmp[16] = {};
- int nr_bytes;
- /* For pointer types, pointer size is not defined on a per-type basis.
- * On dump creation however, we store the pointer size.
- */
- if (btf_kind(t) == BTF_KIND_PTR)
- nr_bytes = d->ptr_sz;
- else
- nr_bytes = t->size;
- if (nr_bytes < 1 || nr_bytes > 16) {
- pr_warn("unexpected size %d for id [%u]\n", nr_bytes, id);
- return -EINVAL;
- }
- if (memcmp(data, bytecmp, nr_bytes) == 0)
- return -ENODATA;
- return 0;
- }
- static bool ptr_is_aligned(const struct btf *btf, __u32 type_id,
- const void *data)
- {
- int alignment = btf__align_of(btf, type_id);
- if (alignment == 0)
- return false;
- return ((uintptr_t)data) % alignment == 0;
- }
- static int btf_dump_int_data(struct btf_dump *d,
- const struct btf_type *t,
- __u32 type_id,
- const void *data,
- __u8 bits_offset)
- {
- __u8 encoding = btf_int_encoding(t);
- bool sign = encoding & BTF_INT_SIGNED;
- char buf[16] __attribute__((aligned(16)));
- int sz = t->size;
- if (sz == 0 || sz > sizeof(buf)) {
- pr_warn("unexpected size %d for id [%u]\n", sz, type_id);
- return -EINVAL;
- }
- /* handle packed int data - accesses of integers not aligned on
- * int boundaries can cause problems on some platforms.
- */
- if (!ptr_is_aligned(d->btf, type_id, data)) {
- memcpy(buf, data, sz);
- data = buf;
- }
- switch (sz) {
- case 16: {
- const __u64 *ints = data;
- __u64 lsi, msi;
- /* avoid use of __int128 as some 32-bit platforms do not
- * support it.
- */
- #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
- lsi = ints[0];
- msi = ints[1];
- #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
- lsi = ints[1];
- msi = ints[0];
- #else
- # error "Unrecognized __BYTE_ORDER__"
- #endif
- if (msi == 0)
- btf_dump_type_values(d, "0x%llx", (unsigned long long)lsi);
- else
- btf_dump_type_values(d, "0x%llx%016llx", (unsigned long long)msi,
- (unsigned long long)lsi);
- break;
- }
- case 8:
- if (sign)
- btf_dump_type_values(d, "%lld", *(long long *)data);
- else
- btf_dump_type_values(d, "%llu", *(unsigned long long *)data);
- break;
- case 4:
- if (sign)
- btf_dump_type_values(d, "%d", *(__s32 *)data);
- else
- btf_dump_type_values(d, "%u", *(__u32 *)data);
- break;
- case 2:
- if (sign)
- btf_dump_type_values(d, "%d", *(__s16 *)data);
- else
- btf_dump_type_values(d, "%u", *(__u16 *)data);
- break;
- case 1:
- if (d->typed_dump->is_array_char) {
- /* check for null terminator */
- if (d->typed_dump->is_array_terminated)
- break;
- if (*(char *)data == '\0') {
- d->typed_dump->is_array_terminated = true;
- break;
- }
- if (isprint(*(char *)data)) {
- btf_dump_type_values(d, "'%c'", *(char *)data);
- break;
- }
- }
- if (sign)
- btf_dump_type_values(d, "%d", *(__s8 *)data);
- else
- btf_dump_type_values(d, "%u", *(__u8 *)data);
- break;
- default:
- pr_warn("unexpected sz %d for id [%u]\n", sz, type_id);
- return -EINVAL;
- }
- return 0;
- }
- union float_data {
- long double ld;
- double d;
- float f;
- };
- static int btf_dump_float_data(struct btf_dump *d,
- const struct btf_type *t,
- __u32 type_id,
- const void *data)
- {
- const union float_data *flp = data;
- union float_data fl;
- int sz = t->size;
- /* handle unaligned data; copy to local union */
- if (!ptr_is_aligned(d->btf, type_id, data)) {
- memcpy(&fl, data, sz);
- flp = &fl;
- }
- switch (sz) {
- case 16:
- btf_dump_type_values(d, "%Lf", flp->ld);
- break;
- case 8:
- btf_dump_type_values(d, "%lf", flp->d);
- break;
- case 4:
- btf_dump_type_values(d, "%f", flp->f);
- break;
- default:
- pr_warn("unexpected size %d for id [%u]\n", sz, type_id);
- return -EINVAL;
- }
- return 0;
- }
- static int btf_dump_var_data(struct btf_dump *d,
- const struct btf_type *v,
- __u32 id,
- const void *data)
- {
- enum btf_func_linkage linkage = btf_var(v)->linkage;
- const struct btf_type *t;
- const char *l;
- __u32 type_id;
- switch (linkage) {
- case BTF_FUNC_STATIC:
- l = "static ";
- break;
- case BTF_FUNC_EXTERN:
- l = "extern ";
- break;
- case BTF_FUNC_GLOBAL:
- default:
- l = "";
- break;
- }
- /* format of output here is [linkage] [type] [varname] = (type)value,
- * for example "static int cpu_profile_flip = (int)1"
- */
- btf_dump_printf(d, "%s", l);
- type_id = v->type;
- t = btf__type_by_id(d->btf, type_id);
- btf_dump_emit_type_cast(d, type_id, false);
- btf_dump_printf(d, " %s = ", btf_name_of(d, v->name_off));
- return btf_dump_dump_type_data(d, NULL, t, type_id, data, 0, 0);
- }
- static int btf_dump_array_data(struct btf_dump *d,
- const struct btf_type *t,
- __u32 id,
- const void *data)
- {
- const struct btf_array *array = btf_array(t);
- const struct btf_type *elem_type;
- __u32 i, elem_type_id;
- __s64 elem_size;
- bool is_array_member;
- elem_type_id = array->type;
- elem_type = skip_mods_and_typedefs(d->btf, elem_type_id, NULL);
- elem_size = btf__resolve_size(d->btf, elem_type_id);
- if (elem_size <= 0) {
- pr_warn("unexpected elem size %zd for array type [%u]\n",
- (ssize_t)elem_size, id);
- return -EINVAL;
- }
- if (btf_is_int(elem_type)) {
- /*
- * BTF_INT_CHAR encoding never seems to be set for
- * char arrays, so if size is 1 and element is
- * printable as a char, we'll do that.
- */
- if (elem_size == 1)
- d->typed_dump->is_array_char = true;
- }
- /* note that we increment depth before calling btf_dump_print() below;
- * this is intentional. btf_dump_data_newline() will not print a
- * newline for depth 0 (since this leaves us with trailing newlines
- * at the end of typed display), so depth is incremented first.
- * For similar reasons, we decrement depth before showing the closing
- * parenthesis.
- */
- d->typed_dump->depth++;
- btf_dump_printf(d, "[%s", btf_dump_data_newline(d));
- /* may be a multidimensional array, so store current "is array member"
- * status so we can restore it correctly later.
- */
- is_array_member = d->typed_dump->is_array_member;
- d->typed_dump->is_array_member = true;
- for (i = 0; i < array->nelems; i++, data += elem_size) {
- if (d->typed_dump->is_array_terminated)
- break;
- btf_dump_dump_type_data(d, NULL, elem_type, elem_type_id, data, 0, 0);
- }
- d->typed_dump->is_array_member = is_array_member;
- d->typed_dump->depth--;
- btf_dump_data_pfx(d);
- btf_dump_type_values(d, "]");
- return 0;
- }
- static int btf_dump_struct_data(struct btf_dump *d,
- const struct btf_type *t,
- __u32 id,
- const void *data)
- {
- const struct btf_member *m = btf_members(t);
- __u16 n = btf_vlen(t);
- int i, err = 0;
- /* note that we increment depth before calling btf_dump_print() below;
- * this is intentional. btf_dump_data_newline() will not print a
- * newline for depth 0 (since this leaves us with trailing newlines
- * at the end of typed display), so depth is incremented first.
- * For similar reasons, we decrement depth before showing the closing
- * parenthesis.
- */
- d->typed_dump->depth++;
- btf_dump_printf(d, "{%s", btf_dump_data_newline(d));
- for (i = 0; i < n; i++, m++) {
- const struct btf_type *mtype;
- const char *mname;
- __u32 moffset;
- __u8 bit_sz;
- mtype = btf__type_by_id(d->btf, m->type);
- mname = btf_name_of(d, m->name_off);
- moffset = btf_member_bit_offset(t, i);
- bit_sz = btf_member_bitfield_size(t, i);
- err = btf_dump_dump_type_data(d, mname, mtype, m->type, data + moffset / 8,
- moffset % 8, bit_sz);
- if (err < 0)
- return err;
- }
- d->typed_dump->depth--;
- btf_dump_data_pfx(d);
- btf_dump_type_values(d, "}");
- return err;
- }
- union ptr_data {
- unsigned int p;
- unsigned long long lp;
- };
- static int btf_dump_ptr_data(struct btf_dump *d,
- const struct btf_type *t,
- __u32 id,
- const void *data)
- {
- if (ptr_is_aligned(d->btf, id, data) && d->ptr_sz == sizeof(void *)) {
- btf_dump_type_values(d, "%p", *(void **)data);
- } else {
- union ptr_data pt;
- memcpy(&pt, data, d->ptr_sz);
- if (d->ptr_sz == 4)
- btf_dump_type_values(d, "0x%x", pt.p);
- else
- btf_dump_type_values(d, "0x%llx", pt.lp);
- }
- return 0;
- }
- static int btf_dump_get_enum_value(struct btf_dump *d,
- const struct btf_type *t,
- const void *data,
- __u32 id,
- __s64 *value)
- {
- bool is_signed = btf_kflag(t);
- if (!ptr_is_aligned(d->btf, id, data)) {
- __u64 val;
- int err;
- err = btf_dump_get_bitfield_value(d, t, data, 0, 0, &val);
- if (err)
- return err;
- *value = (__s64)val;
- return 0;
- }
- switch (t->size) {
- case 8:
- *value = *(__s64 *)data;
- return 0;
- case 4:
- *value = is_signed ? (__s64)*(__s32 *)data : *(__u32 *)data;
- return 0;
- case 2:
- *value = is_signed ? *(__s16 *)data : *(__u16 *)data;
- return 0;
- case 1:
- *value = is_signed ? *(__s8 *)data : *(__u8 *)data;
- return 0;
- default:
- pr_warn("unexpected size %d for enum, id:[%u]\n", t->size, id);
- return -EINVAL;
- }
- }
- static int btf_dump_enum_data(struct btf_dump *d,
- const struct btf_type *t,
- __u32 id,
- const void *data)
- {
- bool is_signed;
- __s64 value;
- int i, err;
- err = btf_dump_get_enum_value(d, t, data, id, &value);
- if (err)
- return err;
- is_signed = btf_kflag(t);
- if (btf_is_enum(t)) {
- const struct btf_enum *e;
- for (i = 0, e = btf_enum(t); i < btf_vlen(t); i++, e++) {
- if (value != e->val)
- continue;
- btf_dump_type_values(d, "%s", btf_name_of(d, e->name_off));
- return 0;
- }
- btf_dump_type_values(d, is_signed ? "%d" : "%u", value);
- } else {
- const struct btf_enum64 *e;
- for (i = 0, e = btf_enum64(t); i < btf_vlen(t); i++, e++) {
- if (value != btf_enum64_value(e))
- continue;
- btf_dump_type_values(d, "%s", btf_name_of(d, e->name_off));
- return 0;
- }
- btf_dump_type_values(d, is_signed ? "%lldLL" : "%lluULL",
- (unsigned long long)value);
- }
- return 0;
- }
- static int btf_dump_datasec_data(struct btf_dump *d,
- const struct btf_type *t,
- __u32 id,
- const void *data)
- {
- const struct btf_var_secinfo *vsi;
- const struct btf_type *var;
- __u32 i;
- int err;
- btf_dump_type_values(d, "SEC(\"%s\") ", btf_name_of(d, t->name_off));
- for (i = 0, vsi = btf_var_secinfos(t); i < btf_vlen(t); i++, vsi++) {
- var = btf__type_by_id(d->btf, vsi->type);
- err = btf_dump_dump_type_data(d, NULL, var, vsi->type, data + vsi->offset, 0, 0);
- if (err < 0)
- return err;
- btf_dump_printf(d, ";");
- }
- return 0;
- }
- /* return size of type, or if base type overflows, return -E2BIG. */
- static int btf_dump_type_data_check_overflow(struct btf_dump *d,
- const struct btf_type *t,
- __u32 id,
- const void *data,
- __u8 bits_offset,
- __u8 bit_sz)
- {
- __s64 size;
- if (bit_sz) {
- /* bits_offset is at most 7. bit_sz is at most 128. */
- __u8 nr_bytes = (bits_offset + bit_sz + 7) / 8;
- /* When bit_sz is non zero, it is called from
- * btf_dump_struct_data() where it only cares about
- * negative error value.
- * Return nr_bytes in success case to make it
- * consistent as the regular integer case below.
- */
- return data + nr_bytes > d->typed_dump->data_end ? -E2BIG : nr_bytes;
- }
- size = btf__resolve_size(d->btf, id);
- if (size < 0 || size >= INT_MAX) {
- pr_warn("unexpected size [%zu] for id [%u]\n",
- (size_t)size, id);
- return -EINVAL;
- }
- /* Only do overflow checking for base types; we do not want to
- * avoid showing part of a struct, union or array, even if we
- * do not have enough data to show the full object. By
- * restricting overflow checking to base types we can ensure
- * that partial display succeeds, while avoiding overflowing
- * and using bogus data for display.
- */
- t = skip_mods_and_typedefs(d->btf, id, NULL);
- if (!t) {
- pr_warn("unexpected error skipping mods/typedefs for id [%u]\n",
- id);
- return -EINVAL;
- }
- switch (btf_kind(t)) {
- case BTF_KIND_INT:
- case BTF_KIND_FLOAT:
- case BTF_KIND_PTR:
- case BTF_KIND_ENUM:
- case BTF_KIND_ENUM64:
- if (data + bits_offset / 8 + size > d->typed_dump->data_end)
- return -E2BIG;
- break;
- default:
- break;
- }
- return (int)size;
- }
- static int btf_dump_type_data_check_zero(struct btf_dump *d,
- const struct btf_type *t,
- __u32 id,
- const void *data,
- __u8 bits_offset,
- __u8 bit_sz)
- {
- __s64 value;
- int i, err;
- /* toplevel exceptions; we show zero values if
- * - we ask for them (emit_zeros)
- * - if we are at top-level so we see "struct empty { }"
- * - or if we are an array member and the array is non-empty and
- * not a char array; we don't want to be in a situation where we
- * have an integer array 0, 1, 0, 1 and only show non-zero values.
- * If the array contains zeroes only, or is a char array starting
- * with a '\0', the array-level check_zero() will prevent showing it;
- * we are concerned with determining zero value at the array member
- * level here.
- */
- if (d->typed_dump->emit_zeroes || d->typed_dump->depth == 0 ||
- (d->typed_dump->is_array_member &&
- !d->typed_dump->is_array_char))
- return 0;
- t = skip_mods_and_typedefs(d->btf, id, NULL);
- switch (btf_kind(t)) {
- case BTF_KIND_INT:
- if (bit_sz)
- return btf_dump_bitfield_check_zero(d, t, data, bits_offset, bit_sz);
- return btf_dump_base_type_check_zero(d, t, id, data);
- case BTF_KIND_FLOAT:
- case BTF_KIND_PTR:
- return btf_dump_base_type_check_zero(d, t, id, data);
- case BTF_KIND_ARRAY: {
- const struct btf_array *array = btf_array(t);
- const struct btf_type *elem_type;
- __u32 elem_type_id, elem_size;
- bool ischar;
- elem_type_id = array->type;
- elem_size = btf__resolve_size(d->btf, elem_type_id);
- elem_type = skip_mods_and_typedefs(d->btf, elem_type_id, NULL);
- ischar = btf_is_int(elem_type) && elem_size == 1;
- /* check all elements; if _any_ element is nonzero, all
- * of array is displayed. We make an exception however
- * for char arrays where the first element is 0; these
- * are considered zeroed also, even if later elements are
- * non-zero because the string is terminated.
- */
- for (i = 0; i < array->nelems; i++) {
- if (i == 0 && ischar && *(char *)data == 0)
- return -ENODATA;
- err = btf_dump_type_data_check_zero(d, elem_type,
- elem_type_id,
- data +
- (i * elem_size),
- bits_offset, 0);
- if (err != -ENODATA)
- return err;
- }
- return -ENODATA;
- }
- case BTF_KIND_STRUCT:
- case BTF_KIND_UNION: {
- const struct btf_member *m = btf_members(t);
- __u16 n = btf_vlen(t);
- /* if any struct/union member is non-zero, the struct/union
- * is considered non-zero and dumped.
- */
- for (i = 0; i < n; i++, m++) {
- const struct btf_type *mtype;
- __u32 moffset;
- mtype = btf__type_by_id(d->btf, m->type);
- moffset = btf_member_bit_offset(t, i);
- /* btf_int_bits() does not store member bitfield size;
- * bitfield size needs to be stored here so int display
- * of member can retrieve it.
- */
- bit_sz = btf_member_bitfield_size(t, i);
- err = btf_dump_type_data_check_zero(d, mtype, m->type, data + moffset / 8,
- moffset % 8, bit_sz);
- if (err != ENODATA)
- return err;
- }
- return -ENODATA;
- }
- case BTF_KIND_ENUM:
- case BTF_KIND_ENUM64:
- err = btf_dump_get_enum_value(d, t, data, id, &value);
- if (err)
- return err;
- if (value == 0)
- return -ENODATA;
- return 0;
- default:
- return 0;
- }
- }
- /* returns size of data dumped, or error. */
- static int btf_dump_dump_type_data(struct btf_dump *d,
- const char *fname,
- const struct btf_type *t,
- __u32 id,
- const void *data,
- __u8 bits_offset,
- __u8 bit_sz)
- {
- int size, err = 0;
- size = btf_dump_type_data_check_overflow(d, t, id, data, bits_offset, bit_sz);
- if (size < 0)
- return size;
- err = btf_dump_type_data_check_zero(d, t, id, data, bits_offset, bit_sz);
- if (err) {
- /* zeroed data is expected and not an error, so simply skip
- * dumping such data. Record other errors however.
- */
- if (err == -ENODATA)
- return size;
- return err;
- }
- btf_dump_data_pfx(d);
- if (!d->typed_dump->skip_names) {
- if (fname && strlen(fname) > 0)
- btf_dump_printf(d, ".%s = ", fname);
- btf_dump_emit_type_cast(d, id, true);
- }
- t = skip_mods_and_typedefs(d->btf, id, NULL);
- switch (btf_kind(t)) {
- case BTF_KIND_UNKN:
- case BTF_KIND_FWD:
- case BTF_KIND_FUNC:
- case BTF_KIND_FUNC_PROTO:
- case BTF_KIND_DECL_TAG:
- err = btf_dump_unsupported_data(d, t, id);
- break;
- case BTF_KIND_INT:
- if (bit_sz)
- err = btf_dump_bitfield_data(d, t, data, bits_offset, bit_sz);
- else
- err = btf_dump_int_data(d, t, id, data, bits_offset);
- break;
- case BTF_KIND_FLOAT:
- err = btf_dump_float_data(d, t, id, data);
- break;
- case BTF_KIND_PTR:
- err = btf_dump_ptr_data(d, t, id, data);
- break;
- case BTF_KIND_ARRAY:
- err = btf_dump_array_data(d, t, id, data);
- break;
- case BTF_KIND_STRUCT:
- case BTF_KIND_UNION:
- err = btf_dump_struct_data(d, t, id, data);
- break;
- case BTF_KIND_ENUM:
- case BTF_KIND_ENUM64:
- /* handle bitfield and int enum values */
- if (bit_sz) {
- __u64 print_num;
- __s64 enum_val;
- err = btf_dump_get_bitfield_value(d, t, data, bits_offset, bit_sz,
- &print_num);
- if (err)
- break;
- enum_val = (__s64)print_num;
- err = btf_dump_enum_data(d, t, id, &enum_val);
- } else
- err = btf_dump_enum_data(d, t, id, data);
- break;
- case BTF_KIND_VAR:
- err = btf_dump_var_data(d, t, id, data);
- break;
- case BTF_KIND_DATASEC:
- err = btf_dump_datasec_data(d, t, id, data);
- break;
- default:
- pr_warn("unexpected kind [%u] for id [%u]\n",
- BTF_INFO_KIND(t->info), id);
- return -EINVAL;
- }
- if (err < 0)
- return err;
- return size;
- }
- int btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
- const void *data, size_t data_sz,
- const struct btf_dump_type_data_opts *opts)
- {
- struct btf_dump_data typed_dump = {};
- const struct btf_type *t;
- int ret;
- if (!OPTS_VALID(opts, btf_dump_type_data_opts))
- return libbpf_err(-EINVAL);
- t = btf__type_by_id(d->btf, id);
- if (!t)
- return libbpf_err(-ENOENT);
- d->typed_dump = &typed_dump;
- d->typed_dump->data_end = data + data_sz;
- d->typed_dump->indent_lvl = OPTS_GET(opts, indent_level, 0);
- /* default indent string is a tab */
- if (!OPTS_GET(opts, indent_str, NULL))
- d->typed_dump->indent_str[0] = '\t';
- else
- libbpf_strlcpy(d->typed_dump->indent_str, opts->indent_str,
- sizeof(d->typed_dump->indent_str));
- d->typed_dump->compact = OPTS_GET(opts, compact, false);
- d->typed_dump->skip_names = OPTS_GET(opts, skip_names, false);
- d->typed_dump->emit_zeroes = OPTS_GET(opts, emit_zeroes, false);
- ret = btf_dump_dump_type_data(d, NULL, t, id, data, 0, 0);
- d->typed_dump = NULL;
- return libbpf_err(ret);
- }
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