From 9c6c5c48d7e9c00c541e0f1a5cea3a96767e825c Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 29 Sep 2020 16:28:40 -0700 Subject: libbpf: Make btf_dump work with modifiable BTF Ensure that btf_dump can accommodate new BTF types being appended to BTF instance after struct btf_dump was created. This came up during attemp to use btf_dump for raw type dumping in selftests, but given changes are not excessive, it's good to not have any gotchas in API usage, so I decided to support such use case in general. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200929232843.1249318-2-andriin@fb.com --- tools/lib/bpf/btf_dump.c | 69 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 47 insertions(+), 22 deletions(-) (limited to 'tools/lib/bpf/btf_dump.c') diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 91310e528a3a..2f9d685bd522 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -60,11 +60,14 @@ struct btf_dump { struct btf_dump_opts opts; int ptr_sz; bool strip_mods; + 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; @@ -113,6 +116,7 @@ static void btf_dump_printf(const struct btf_dump *d, const char *fmt, ...) } 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, const struct btf_ext *btf_ext, @@ -144,25 +148,8 @@ struct btf_dump *btf_dump__new(const struct btf *btf, d->ident_names = NULL; 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); + err = btf_dump_resize(d); if (err) goto err; @@ -172,9 +159,38 @@ err: return ERR_PTR(err); } +static int btf_dump_resize(struct btf_dump *d) +{ + int err, last_id = btf__get_nr_types(d->btf); + + if (last_id <= d->last_id) + return 0; + + if (btf_ensure_mem((void **)&d->type_states, &d->type_states_cap, + sizeof(*d->type_states), last_id + 1)) + return -ENOMEM; + if (btf_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, cnt; + int i; if (IS_ERR_OR_NULL(d)) return; @@ -182,7 +198,7 @@ void btf_dump__free(struct btf_dump *d) free(d->type_states); if (d->cached_names) { /* any set cached name is owned by us and should be freed */ - for (i = 0, cnt = btf__get_nr_types(d->btf); i <= cnt; i++) { + for (i = 0; i <= d->last_id; i++) { if (d->cached_names[i]) free((void *)d->cached_names[i]); } @@ -222,6 +238,10 @@ int btf_dump__dump_type(struct btf_dump *d, __u32 id) if (id > btf__get_nr_types(d->btf)) return -EINVAL; + err = btf_dump_resize(d); + if (err) + return err; + d->emit_queue_cnt = 0; err = btf_dump_order_type(d, id, false); if (err < 0) @@ -251,7 +271,7 @@ static int btf_dump_mark_referenced(struct btf_dump *d) const struct btf_type *t; __u16 vlen; - for (i = 1; i <= n; i++) { + for (i = d->last_id + 1; i <= n; i++) { t = btf__type_by_id(d->btf, i); vlen = btf_vlen(t); @@ -306,6 +326,7 @@ static int btf_dump_mark_referenced(struct btf_dump *d) } return 0; } + static int btf_dump_add_emit_queue_id(struct btf_dump *d, __u32 id) { __u32 *new_queue; @@ -1049,11 +1070,15 @@ 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; + int lvl, err; if (!OPTS_VALID(opts, btf_dump_emit_type_decl_opts)) return -EINVAL; + err = btf_dump_resize(d); + if (err) + return -EINVAL; + fname = OPTS_GET(opts, field_name, ""); lvl = OPTS_GET(opts, indent_level, 0); d->strip_mods = OPTS_GET(opts, strip_mods, false); -- cgit v1.2.3