libbpf: Expose BTF-to-C type declaration emitting API
Expose API that allows to emit type declaration and field/variable definition (if optional field name is specified) in valid C syntax for any provided BTF type. This is going to be used by bpftool when emitting data section layout as a struct. As part of making this API useful in a stand-alone fashion, move initialization of some of the internal btf_dump state to earlier phase. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20191214014341.3442258-8-andriin@fb.com
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@ -126,6 +126,28 @@ LIBBPF_API void btf_dump__free(struct btf_dump *d);
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LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id);
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LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id);
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struct btf_dump_emit_type_decl_opts {
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/* size of this struct, for forward/backward compatiblity */
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size_t sz;
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/* optional field name for type declaration, e.g.:
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* - struct my_struct <FNAME>
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* - void (*<FNAME>)(int)
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* - char (*<FNAME>)[123]
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*/
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const char *field_name;
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/* extra indentation level (in number of tabs) to emit for multi-line
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* type declarations (e.g., anonymous struct); applies for lines
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* starting from the second one (first line is assumed to have
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* necessary indentation already
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*/
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int indent_level;
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};
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#define btf_dump_emit_type_decl_opts__last_field indent_level
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LIBBPF_API int
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btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
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const struct btf_dump_emit_type_decl_opts *opts);
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/*
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/*
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* A set of helpers for easier BTF types handling
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* A set of helpers for easier BTF types handling
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*/
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*/
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@ -116,6 +116,8 @@ static void btf_dump_printf(const struct btf_dump *d, const char *fmt, ...)
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va_end(args);
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va_end(args);
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}
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}
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static int btf_dump_mark_referenced(struct btf_dump *d);
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struct btf_dump *btf_dump__new(const struct btf *btf,
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struct btf_dump *btf_dump__new(const struct btf *btf,
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const struct btf_ext *btf_ext,
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const struct btf_ext *btf_ext,
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const struct btf_dump_opts *opts,
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const struct btf_dump_opts *opts,
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@ -137,18 +139,39 @@ struct btf_dump *btf_dump__new(const struct btf *btf,
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if (IS_ERR(d->type_names)) {
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if (IS_ERR(d->type_names)) {
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err = PTR_ERR(d->type_names);
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err = PTR_ERR(d->type_names);
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d->type_names = NULL;
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d->type_names = NULL;
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btf_dump__free(d);
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return ERR_PTR(err);
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}
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}
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d->ident_names = hashmap__new(str_hash_fn, str_equal_fn, NULL);
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d->ident_names = hashmap__new(str_hash_fn, str_equal_fn, NULL);
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if (IS_ERR(d->ident_names)) {
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if (IS_ERR(d->ident_names)) {
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err = PTR_ERR(d->ident_names);
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err = PTR_ERR(d->ident_names);
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d->ident_names = NULL;
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d->ident_names = NULL;
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btf_dump__free(d);
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goto err;
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return ERR_PTR(err);
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}
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d->type_states = calloc(1 + btf__get_nr_types(d->btf),
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sizeof(d->type_states[0]));
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if (!d->type_states) {
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err = -ENOMEM;
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goto err;
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}
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d->cached_names = calloc(1 + btf__get_nr_types(d->btf),
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sizeof(d->cached_names[0]));
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if (!d->cached_names) {
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err = -ENOMEM;
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goto err;
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}
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}
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/* VOID is special */
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d->type_states[0].order_state = ORDERED;
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d->type_states[0].emit_state = EMITTED;
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/* eagerly determine referenced types for anon enums */
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err = btf_dump_mark_referenced(d);
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if (err)
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goto err;
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return d;
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return d;
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err:
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btf_dump__free(d);
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return ERR_PTR(err);
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}
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}
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void btf_dump__free(struct btf_dump *d)
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void btf_dump__free(struct btf_dump *d)
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@ -175,7 +198,6 @@ void btf_dump__free(struct btf_dump *d)
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free(d);
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free(d);
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}
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}
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static int btf_dump_mark_referenced(struct btf_dump *d);
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static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr);
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static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr);
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static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id);
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static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id);
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@ -202,27 +224,6 @@ int btf_dump__dump_type(struct btf_dump *d, __u32 id)
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if (id > btf__get_nr_types(d->btf))
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if (id > btf__get_nr_types(d->btf))
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return -EINVAL;
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return -EINVAL;
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/* type states are lazily allocated, as they might not be needed */
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if (!d->type_states) {
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d->type_states = calloc(1 + btf__get_nr_types(d->btf),
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sizeof(d->type_states[0]));
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if (!d->type_states)
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return -ENOMEM;
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d->cached_names = calloc(1 + btf__get_nr_types(d->btf),
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sizeof(d->cached_names[0]));
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if (!d->cached_names)
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return -ENOMEM;
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/* VOID is special */
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d->type_states[0].order_state = ORDERED;
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d->type_states[0].emit_state = EMITTED;
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/* eagerly determine referenced types for anon enums */
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err = btf_dump_mark_referenced(d);
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if (err)
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return err;
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}
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d->emit_queue_cnt = 0;
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d->emit_queue_cnt = 0;
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err = btf_dump_order_type(d, id, false);
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err = btf_dump_order_type(d, id, false);
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if (err < 0)
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if (err < 0)
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@ -1016,6 +1017,21 @@ static int btf_dump_push_decl_stack_id(struct btf_dump *d, __u32 id)
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* of a stack frame. Some care is required to "pop" stack frames after
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* of a stack frame. Some care is required to "pop" stack frames after
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* processing type declaration chain.
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* processing type declaration chain.
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*/
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*/
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int btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
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const struct btf_dump_emit_type_decl_opts *opts)
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{
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const char *fname;
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int lvl;
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if (!OPTS_VALID(opts, btf_dump_emit_type_decl_opts))
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return -EINVAL;
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fname = OPTS_GET(opts, field_name, NULL);
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lvl = OPTS_GET(opts, indent_level, 0);
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btf_dump_emit_type_decl(d, id, fname, lvl);
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return 0;
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}
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static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id,
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static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id,
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const char *fname, int lvl)
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const char *fname, int lvl)
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{
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{
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@ -211,6 +211,7 @@ LIBBPF_0.0.6 {
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LIBBPF_0.0.7 {
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LIBBPF_0.0.7 {
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global:
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global:
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btf_dump__emit_type_decl;
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bpf_program__attach;
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bpf_program__attach;
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btf__align_of;
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btf__align_of;
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} LIBBPF_0.0.6;
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} LIBBPF_0.0.6;
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