| Message ID | 20191213223214.2791885-8-andriin@fb.com |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | Add code-generated BPF object skeleton support | expand |
On Fri, Dec 13, 2019 at 02:32:04PM -0800, Andrii Nakryiko wrote: > 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. > > Acked-by: Martin KaFai Lau <kafai@fb.com> > Signed-off-by: Andrii Nakryiko <andriin@fb.com> > --- > tools/lib/bpf/btf.h | 22 ++++++++++++++ > tools/lib/bpf/btf_dump.c | 62 +++++++++++++++++++++++----------------- > tools/lib/bpf/libbpf.map | 1 + > 3 files changed, 59 insertions(+), 26 deletions(-) > > diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h > index a114c8ef4f08..1f9625946ead 100644 > --- a/tools/lib/bpf/btf.h > +++ b/tools/lib/bpf/btf.h > @@ -126,6 +126,28 @@ LIBBPF_API void btf_dump__free(struct btf_dump *d); > > LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id); > > +struct btf_dump_emit_type_decl_opts { > + /* size of this struct, for forward/backward compatiblity */ > + size_t sz; > + /* optional field name for type declaration, e.g.: > + * - struct my_struct <FNAME> > + * - void (*<FNAME>)(int) > + * - char (*<FNAME>)[123] > + */ > + const char *field_name; > + /* extra indentation level (in number of tabs) to emit for multi-line > + * type declarations (e.g., anonymous struct); applies for lines > + * starting from the second one (first line is assumed to have > + * necessary indentation already > + */ > + int indent_level; > +}; > +#define btf_dump_emit_type_decl_opts__last_field attach_prog_fd OPTS_VALID() is missing in btf_dump__emit_type_decl() ? Otherwise it would have caught above typo. > 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; > - btf_dump__free(d); > - return ERR_PTR(err); > + goto err; > + } > + d->type_states = calloc(1 + btf__get_nr_types(d->btf), > + sizeof(d->type_states[0])); > + if (!d->type_states) { > + err = -ENOMEM; > + goto err; > + } > + d->cached_names = calloc(1 + btf__get_nr_types(d->btf), > + sizeof(d->cached_names[0])); > + if (!d->cached_names) { > + err = -ENOMEM; > + goto err; > } > > + /* VOID is special */ > + d->type_states[0].order_state = ORDERED; > + d->type_states[0].emit_state = EMITTED; Not following the logic with 1 + btf__get_nr_types(d->btf) and above init... type_states[0] is void. true. But btf__get_nr_types() includes that type_id=0 == void. So what this 1+ is for? I know it's just a move of old code. I just noticed. Would be great to add a comment.
On Fri, Dec 13, 2019 at 3:50 PM Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote: > > On Fri, Dec 13, 2019 at 02:32:04PM -0800, Andrii Nakryiko wrote: > > 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. > > > > Acked-by: Martin KaFai Lau <kafai@fb.com> > > Signed-off-by: Andrii Nakryiko <andriin@fb.com> > > --- > > tools/lib/bpf/btf.h | 22 ++++++++++++++ > > tools/lib/bpf/btf_dump.c | 62 +++++++++++++++++++++++----------------- > > tools/lib/bpf/libbpf.map | 1 + > > 3 files changed, 59 insertions(+), 26 deletions(-) > > > > diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h > > index a114c8ef4f08..1f9625946ead 100644 > > --- a/tools/lib/bpf/btf.h > > +++ b/tools/lib/bpf/btf.h > > @@ -126,6 +126,28 @@ LIBBPF_API void btf_dump__free(struct btf_dump *d); > > > > LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id); > > > > +struct btf_dump_emit_type_decl_opts { > > + /* size of this struct, for forward/backward compatiblity */ > > + size_t sz; > > + /* optional field name for type declaration, e.g.: > > + * - struct my_struct <FNAME> > > + * - void (*<FNAME>)(int) > > + * - char (*<FNAME>)[123] > > + */ > > + const char *field_name; > > + /* extra indentation level (in number of tabs) to emit for multi-line > > + * type declarations (e.g., anonymous struct); applies for lines > > + * starting from the second one (first line is assumed to have > > + * necessary indentation already > > + */ > > + int indent_level; > > +}; > > +#define btf_dump_emit_type_decl_opts__last_field attach_prog_fd > > OPTS_VALID() is missing in btf_dump__emit_type_decl() ? > Otherwise it would have caught above typo. duh... right, very good catch, thanks! > > > > 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; > > - btf_dump__free(d); > > - return ERR_PTR(err); > > + goto err; > > + } > > + d->type_states = calloc(1 + btf__get_nr_types(d->btf), > > + sizeof(d->type_states[0])); > > + if (!d->type_states) { > > + err = -ENOMEM; > > + goto err; > > + } > > + d->cached_names = calloc(1 + btf__get_nr_types(d->btf), > > + sizeof(d->cached_names[0])); > > + if (!d->cached_names) { > > + err = -ENOMEM; > > + goto err; > > } > > > > + /* VOID is special */ > > + d->type_states[0].order_state = ORDERED; > > + d->type_states[0].emit_state = EMITTED; > > Not following the logic with 1 + btf__get_nr_types(d->btf) and > above init... > type_states[0] is void. true. > But btf__get_nr_types() includes that type_id=0 == void. > So what this 1+ is for? > I know it's just a move of old code. I just noticed. > Would be great to add a comment. btf__get_nr_types() does not actually include void, thus we need +1. It is confusing, I agree, but is consistent throughout libbpf. >
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index a114c8ef4f08..1f9625946ead 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -126,6 +126,28 @@ LIBBPF_API void btf_dump__free(struct btf_dump *d); LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id); +struct btf_dump_emit_type_decl_opts { + /* size of this struct, for forward/backward compatiblity */ + size_t sz; + /* optional field name for type declaration, e.g.: + * - struct my_struct <FNAME> + * - void (*<FNAME>)(int) + * - char (*<FNAME>)[123] + */ + const char *field_name; + /* extra indentation level (in number of tabs) to emit for multi-line + * type declarations (e.g., anonymous struct); applies for lines + * starting from the second one (first line is assumed to have + * necessary indentation already + */ + int indent_level; +}; +#define btf_dump_emit_type_decl_opts__last_field attach_prog_fd + +LIBBPF_API void +btf_dump__emit_type_decl(struct btf_dump *d, __u32 id, + const struct btf_dump_emit_type_decl_opts *opts); + /* * A set of helpers for easier BTF types handling */ diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 53393026d085..b7a7a2ef785a 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -116,6 +116,8 @@ static void btf_dump_printf(const struct btf_dump *d, const char *fmt, ...) va_end(args); } +static int btf_dump_mark_referenced(struct btf_dump *d); + struct btf_dump *btf_dump__new(const struct btf *btf, const struct btf_ext *btf_ext, const struct btf_dump_opts *opts, @@ -137,18 +139,39 @@ struct btf_dump *btf_dump__new(const struct btf *btf, if (IS_ERR(d->type_names)) { err = PTR_ERR(d->type_names); d->type_names = NULL; - btf_dump__free(d); - return ERR_PTR(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; - btf_dump__free(d); - return ERR_PTR(err); + goto err; + } + d->type_states = calloc(1 + btf__get_nr_types(d->btf), + sizeof(d->type_states[0])); + if (!d->type_states) { + err = -ENOMEM; + goto err; + } + d->cached_names = calloc(1 + btf__get_nr_types(d->btf), + sizeof(d->cached_names[0])); + if (!d->cached_names) { + err = -ENOMEM; + goto err; } + /* 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) + goto err; + return d; +err: + btf_dump__free(d); + return ERR_PTR(err); } void btf_dump__free(struct btf_dump *d) @@ -175,7 +198,6 @@ void btf_dump__free(struct btf_dump *d) free(d); } -static int btf_dump_mark_referenced(struct btf_dump *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); @@ -202,27 +224,6 @@ int btf_dump__dump_type(struct btf_dump *d, __u32 id) if (id > btf__get_nr_types(d->btf)) return -EINVAL; - /* type states are lazily allocated, as they might not be needed */ - if (!d->type_states) { - d->type_states = calloc(1 + btf__get_nr_types(d->btf), - sizeof(d->type_states[0])); - if (!d->type_states) - return -ENOMEM; - d->cached_names = calloc(1 + btf__get_nr_types(d->btf), - sizeof(d->cached_names[0])); - if (!d->cached_names) - return -ENOMEM; - - /* 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->emit_queue_cnt = 0; err = btf_dump_order_type(d, id, false); if (err < 0) @@ -1016,6 +1017,15 @@ static int btf_dump_push_decl_stack_id(struct btf_dump *d, __u32 id) * of a stack frame. Some care is required to "pop" stack frames after * processing type declaration chain. */ +void btf_dump__emit_type_decl(struct btf_dump *d, __u32 id, + const struct btf_dump_emit_type_decl_opts *opts) +{ + const char *fname = OPTS_GET(opts, field_name, NULL); + int lvl = OPTS_GET(opts, indent_level, 0); + + btf_dump_emit_type_decl(d, id, fname, lvl); +} + static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id, const char *fname, int lvl) { diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index e7fcca36f186..990c7c0e2d9f 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -211,6 +211,7 @@ LIBBPF_0.0.6 { LIBBPF_0.0.7 { global: + btf_dump__emit_type_decl; bpf_program__attach; btf__align_of; } LIBBPF_0.0.6;