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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;
 }
 
 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);
     hashmap__free(d->type_names);
     hashmap__free(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 align, i, bit_sz;
     __u16 vlen;
 
     align = btf__align_of(btf, id);
     /* size of a non-packed struct has to be a multiple of its alignment*/
     if (align && t->size % align)
         return true;
 
     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;
     }
 
     /*
      * if original struct was marked as packed, but its layout is
      * naturally aligned, we'll detect that it's not packed
      */
     return false;
 }
 
 static int chip_away_bits(int total, int at_most)
 {
     return total % at_most ? : at_most;
 }
 
 static void btf_dump_emit_bit_padding(const struct btf_dump *d,
                       int cur_off, int m_off, int m_bit_sz,
                       int align, int lvl)
 {
     int off_diff = m_off - cur_off;
     int ptr_bits = d->ptr_sz * 8;
 
     if (off_diff <= 0)
         /* no gap */
         return;
     if (m_bit_sz == 0 && off_diff < align * 8)
         /* natural padding will take care of a gap */
         return;
 
     while (off_diff > 0) {
         const char *pad_type;
         int pad_bits;
 
         if (ptr_bits > 32 && off_diff > 32) {
             pad_type = "long";
             pad_bits = chip_away_bits(off_diff, ptr_bits);
         } else if (off_diff > 16) {
             pad_type = "int";
             pad_bits = chip_away_bits(off_diff, 32);
         } else if (off_diff > 8) {
             pad_type = "short";
             pad_bits = chip_away_bits(off_diff, 16);
         } else {
             pad_type = "char";
             pad_bits = chip_away_bits(off_diff, 8);
         }
         btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type, pad_bits);
         off_diff -= pad_bits;
     }
 }
 
 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);
     int align, i, packed, off = 0;
     __u16 vlen = btf_vlen(t);
 
     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;
 
         fname = btf_name_of(d, m->name_off);
         m_sz = btf_member_bitfield_size(t, i);
         m_off = btf_member_bit_offset(t, i);
         align = packed ? 1 : btf__align_of(d->btf, m->type);
 
         btf_dump_emit_bit_padding(d, off, m_off, m_sz, align, 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;
         } else {
             m_sz = max((__s64)0, btf__resolve_size(d->btf, m->type));
             off = m_off + m_sz * 8;
         }
         btf_dump_printf(d, ";");
     }
 
     /* pad at the end, if necessary */
     if (is_struct) {
         align = packed ? 1 : btf__align_of(d->btf, id);
         btf_dump_emit_bit_padding(d, off, t->size * 8, 0, align,
                       lvl + 1);
     }
 
     if (vlen)
         btf_dump_printf(d, "\n");
     btf_dump_printf(d, "%s}", pfx(lvl));
     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)
 {
     size_t dup_cnt = 0;
 
     hashmap__find(name_map, orig_name, (void **)&dup_cnt);
     dup_cnt++;
     hashmap__set(name_map, orig_name, (void *)dup_cnt, NULL, NULL);
 
     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;
 
     /* 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)
 {
     __s64 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);
     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->indent_str)
         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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