diff options
Diffstat (limited to 'tools/bpf/bpftool/btf.c')
| -rw-r--r-- | tools/bpf/bpftool/btf.c | 1471 |
1 files changed, 1471 insertions, 0 deletions
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c new file mode 100644 index 000000000000..946612029dee --- /dev/null +++ b/tools/bpf/bpftool/btf.c @@ -0,0 +1,1471 @@ +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +/* Copyright (C) 2019 Facebook */ + +#ifndef _GNU_SOURCE +#define _GNU_SOURCE +#endif +#include <errno.h> +#include <fcntl.h> +#include <linux/err.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <linux/btf.h> +#include <sys/types.h> +#include <sys/stat.h> + +#include <bpf/bpf.h> +#include <bpf/btf.h> +#include <bpf/hashmap.h> +#include <bpf/libbpf.h> + +#include "json_writer.h" +#include "main.h" + +#define KFUNC_DECL_TAG "bpf_kfunc" +#define FASTCALL_DECL_TAG "bpf_fastcall" + +#define MAX_ROOT_IDS 16 + +static const char * const btf_kind_str[NR_BTF_KINDS] = { + [BTF_KIND_UNKN] = "UNKNOWN", + [BTF_KIND_INT] = "INT", + [BTF_KIND_PTR] = "PTR", + [BTF_KIND_ARRAY] = "ARRAY", + [BTF_KIND_STRUCT] = "STRUCT", + [BTF_KIND_UNION] = "UNION", + [BTF_KIND_ENUM] = "ENUM", + [BTF_KIND_FWD] = "FWD", + [BTF_KIND_TYPEDEF] = "TYPEDEF", + [BTF_KIND_VOLATILE] = "VOLATILE", + [BTF_KIND_CONST] = "CONST", + [BTF_KIND_RESTRICT] = "RESTRICT", + [BTF_KIND_FUNC] = "FUNC", + [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO", + [BTF_KIND_VAR] = "VAR", + [BTF_KIND_DATASEC] = "DATASEC", + [BTF_KIND_FLOAT] = "FLOAT", + [BTF_KIND_DECL_TAG] = "DECL_TAG", + [BTF_KIND_TYPE_TAG] = "TYPE_TAG", + [BTF_KIND_ENUM64] = "ENUM64", +}; + +struct sort_datum { + int index; + int type_rank; + const char *sort_name; + const char *own_name; + __u64 disambig_hash; +}; + +static const char *btf_int_enc_str(__u8 encoding) +{ + switch (encoding) { + case 0: + return "(none)"; + case BTF_INT_SIGNED: + return "SIGNED"; + case BTF_INT_CHAR: + return "CHAR"; + case BTF_INT_BOOL: + return "BOOL"; + default: + return "UNKN"; + } +} + +static const char *btf_var_linkage_str(__u32 linkage) +{ + switch (linkage) { + case BTF_VAR_STATIC: + return "static"; + case BTF_VAR_GLOBAL_ALLOCATED: + return "global"; + case BTF_VAR_GLOBAL_EXTERN: + return "extern"; + default: + return "(unknown)"; + } +} + +static const char *btf_func_linkage_str(const struct btf_type *t) +{ + switch (btf_vlen(t)) { + case BTF_FUNC_STATIC: + return "static"; + case BTF_FUNC_GLOBAL: + return "global"; + case BTF_FUNC_EXTERN: + return "extern"; + default: + return "(unknown)"; + } +} + +static const char *btf_str(const struct btf *btf, __u32 off) +{ + if (!off) + return "(anon)"; + return btf__name_by_offset(btf, off) ? : "(invalid)"; +} + +static int btf_kind_safe(int kind) +{ + return kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN; +} + +static int dump_btf_type(const struct btf *btf, __u32 id, + const struct btf_type *t) +{ + json_writer_t *w = json_wtr; + int kind = btf_kind(t); + + if (json_output) { + jsonw_start_object(w); + jsonw_uint_field(w, "id", id); + jsonw_string_field(w, "kind", btf_kind_str[btf_kind_safe(kind)]); + jsonw_string_field(w, "name", btf_str(btf, t->name_off)); + } else { + printf("[%u] %s '%s'", id, btf_kind_str[btf_kind_safe(kind)], + btf_str(btf, t->name_off)); + } + + switch (kind) { + case BTF_KIND_INT: { + __u32 v = *(__u32 *)(t + 1); + const char *enc; + + enc = btf_int_enc_str(BTF_INT_ENCODING(v)); + + if (json_output) { + jsonw_uint_field(w, "size", t->size); + jsonw_uint_field(w, "bits_offset", BTF_INT_OFFSET(v)); + jsonw_uint_field(w, "nr_bits", BTF_INT_BITS(v)); + jsonw_string_field(w, "encoding", enc); + } else { + printf(" size=%u bits_offset=%u nr_bits=%u encoding=%s", + t->size, BTF_INT_OFFSET(v), BTF_INT_BITS(v), + enc); + } + break; + } + case BTF_KIND_PTR: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_TYPEDEF: + case BTF_KIND_TYPE_TAG: + if (json_output) + jsonw_uint_field(w, "type_id", t->type); + else + printf(" type_id=%u", t->type); + break; + case BTF_KIND_ARRAY: { + const struct btf_array *arr = (const void *)(t + 1); + + if (json_output) { + jsonw_uint_field(w, "type_id", arr->type); + jsonw_uint_field(w, "index_type_id", arr->index_type); + jsonw_uint_field(w, "nr_elems", arr->nelems); + } else { + printf(" type_id=%u index_type_id=%u nr_elems=%u", + arr->type, arr->index_type, arr->nelems); + } + break; + } + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + const struct btf_member *m = (const void *)(t + 1); + __u16 vlen = BTF_INFO_VLEN(t->info); + int i; + + if (json_output) { + jsonw_uint_field(w, "size", t->size); + jsonw_uint_field(w, "vlen", vlen); + jsonw_name(w, "members"); + jsonw_start_array(w); + } else { + printf(" size=%u vlen=%u", t->size, vlen); + } + for (i = 0; i < vlen; i++, m++) { + const char *name = btf_str(btf, m->name_off); + __u32 bit_off, bit_sz; + + if (BTF_INFO_KFLAG(t->info)) { + bit_off = BTF_MEMBER_BIT_OFFSET(m->offset); + bit_sz = BTF_MEMBER_BITFIELD_SIZE(m->offset); + } else { + bit_off = m->offset; + bit_sz = 0; + } + + if (json_output) { + jsonw_start_object(w); + jsonw_string_field(w, "name", name); + jsonw_uint_field(w, "type_id", m->type); + jsonw_uint_field(w, "bits_offset", bit_off); + if (bit_sz) { + jsonw_uint_field(w, "bitfield_size", + bit_sz); + } + jsonw_end_object(w); + } else { + printf("\n\t'%s' type_id=%u bits_offset=%u", + name, m->type, bit_off); + if (bit_sz) + printf(" bitfield_size=%u", bit_sz); + } + } + if (json_output) + jsonw_end_array(w); + break; + } + case BTF_KIND_ENUM: { + const struct btf_enum *v = (const void *)(t + 1); + __u16 vlen = BTF_INFO_VLEN(t->info); + const char *encoding; + int i; + + encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED"; + if (json_output) { + jsonw_string_field(w, "encoding", encoding); + jsonw_uint_field(w, "size", t->size); + jsonw_uint_field(w, "vlen", vlen); + jsonw_name(w, "values"); + jsonw_start_array(w); + } else { + printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen); + } + for (i = 0; i < vlen; i++, v++) { + const char *name = btf_str(btf, v->name_off); + + if (json_output) { + jsonw_start_object(w); + jsonw_string_field(w, "name", name); + if (btf_kflag(t)) + jsonw_int_field(w, "val", v->val); + else + jsonw_uint_field(w, "val", v->val); + jsonw_end_object(w); + } else { + if (btf_kflag(t)) + printf("\n\t'%s' val=%d", name, v->val); + else + printf("\n\t'%s' val=%u", name, (__u32)v->val); + } + } + if (json_output) + jsonw_end_array(w); + break; + } + case BTF_KIND_ENUM64: { + const struct btf_enum64 *v = btf_enum64(t); + __u16 vlen = btf_vlen(t); + const char *encoding; + int i; + + encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED"; + if (json_output) { + jsonw_string_field(w, "encoding", encoding); + jsonw_uint_field(w, "size", t->size); + jsonw_uint_field(w, "vlen", vlen); + jsonw_name(w, "values"); + jsonw_start_array(w); + } else { + printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen); + } + for (i = 0; i < vlen; i++, v++) { + const char *name = btf_str(btf, v->name_off); + __u64 val = ((__u64)v->val_hi32 << 32) | v->val_lo32; + + if (json_output) { + jsonw_start_object(w); + jsonw_string_field(w, "name", name); + if (btf_kflag(t)) + jsonw_int_field(w, "val", val); + else + jsonw_uint_field(w, "val", val); + jsonw_end_object(w); + } else { + if (btf_kflag(t)) + printf("\n\t'%s' val=%lldLL", name, + (long long)val); + else + printf("\n\t'%s' val=%lluULL", name, + (unsigned long long)val); + } + } + if (json_output) + jsonw_end_array(w); + break; + } + case BTF_KIND_FWD: { + const char *fwd_kind = BTF_INFO_KFLAG(t->info) ? "union" + : "struct"; + + if (json_output) + jsonw_string_field(w, "fwd_kind", fwd_kind); + else + printf(" fwd_kind=%s", fwd_kind); + break; + } + case BTF_KIND_FUNC: { + const char *linkage = btf_func_linkage_str(t); + + if (json_output) { + jsonw_uint_field(w, "type_id", t->type); + jsonw_string_field(w, "linkage", linkage); + } else { + printf(" type_id=%u linkage=%s", t->type, linkage); + } + break; + } + case BTF_KIND_FUNC_PROTO: { + const struct btf_param *p = (const void *)(t + 1); + __u16 vlen = BTF_INFO_VLEN(t->info); + int i; + + if (json_output) { + jsonw_uint_field(w, "ret_type_id", t->type); + jsonw_uint_field(w, "vlen", vlen); + jsonw_name(w, "params"); + jsonw_start_array(w); + } else { + printf(" ret_type_id=%u vlen=%u", t->type, vlen); + } + for (i = 0; i < vlen; i++, p++) { + const char *name = btf_str(btf, p->name_off); + + if (json_output) { + jsonw_start_object(w); + jsonw_string_field(w, "name", name); + jsonw_uint_field(w, "type_id", p->type); + jsonw_end_object(w); + } else { + printf("\n\t'%s' type_id=%u", name, p->type); + } + } + if (json_output) + jsonw_end_array(w); + break; + } + case BTF_KIND_VAR: { + const struct btf_var *v = (const void *)(t + 1); + const char *linkage; + + linkage = btf_var_linkage_str(v->linkage); + + if (json_output) { + jsonw_uint_field(w, "type_id", t->type); + jsonw_string_field(w, "linkage", linkage); + } else { + printf(" type_id=%u, linkage=%s", t->type, linkage); + } + break; + } + case BTF_KIND_DATASEC: { + const struct btf_var_secinfo *v = (const void *)(t + 1); + const struct btf_type *vt; + __u16 vlen = BTF_INFO_VLEN(t->info); + int i; + + if (json_output) { + jsonw_uint_field(w, "size", t->size); + jsonw_uint_field(w, "vlen", vlen); + jsonw_name(w, "vars"); + jsonw_start_array(w); + } else { + printf(" size=%u vlen=%u", t->size, vlen); + } + for (i = 0; i < vlen; i++, v++) { + if (json_output) { + jsonw_start_object(w); + jsonw_uint_field(w, "type_id", v->type); + jsonw_uint_field(w, "offset", v->offset); + jsonw_uint_field(w, "size", v->size); + jsonw_end_object(w); + } else { + printf("\n\ttype_id=%u offset=%u size=%u", + v->type, v->offset, v->size); + + if (v->type < btf__type_cnt(btf)) { + vt = btf__type_by_id(btf, v->type); + printf(" (%s '%s')", + btf_kind_str[btf_kind_safe(btf_kind(vt))], + btf_str(btf, vt->name_off)); + } + } + } + if (json_output) + jsonw_end_array(w); + break; + } + case BTF_KIND_FLOAT: { + if (json_output) + jsonw_uint_field(w, "size", t->size); + else + printf(" size=%u", t->size); + break; + } + case BTF_KIND_DECL_TAG: { + const struct btf_decl_tag *tag = (const void *)(t + 1); + + if (json_output) { + jsonw_uint_field(w, "type_id", t->type); + jsonw_int_field(w, "component_idx", tag->component_idx); + } else { + printf(" type_id=%u component_idx=%d", t->type, tag->component_idx); + } + break; + } + default: + break; + } + + if (json_output) + jsonw_end_object(json_wtr); + else + printf("\n"); + + return 0; +} + +static int dump_btf_raw(const struct btf *btf, + __u32 *root_type_ids, int root_type_cnt) +{ + const struct btf_type *t; + int i; + + if (json_output) { + jsonw_start_object(json_wtr); + jsonw_name(json_wtr, "types"); + jsonw_start_array(json_wtr); + } + + if (root_type_cnt) { + for (i = 0; i < root_type_cnt; i++) { + t = btf__type_by_id(btf, root_type_ids[i]); + dump_btf_type(btf, root_type_ids[i], t); + } + } else { + const struct btf *base; + int cnt = btf__type_cnt(btf); + int start_id = 1; + + base = btf__base_btf(btf); + if (base) + start_id = btf__type_cnt(base); + + for (i = start_id; i < cnt; i++) { + t = btf__type_by_id(btf, i); + dump_btf_type(btf, i, t); + } + } + + if (json_output) { + jsonw_end_array(json_wtr); + jsonw_end_object(json_wtr); + } + return 0; +} + +struct ptr_array { + __u32 cnt; + __u32 cap; + const void **elems; +}; + +static int ptr_array_push(const void *ptr, struct ptr_array *arr) +{ + __u32 new_cap; + void *tmp; + + if (arr->cnt == arr->cap) { + new_cap = (arr->cap ?: 16) * 2; + tmp = realloc(arr->elems, sizeof(*arr->elems) * new_cap); + if (!tmp) + return -ENOMEM; + arr->elems = tmp; + arr->cap = new_cap; + } + arr->elems[arr->cnt++] = ptr; + return 0; +} + +static void ptr_array_free(struct ptr_array *arr) +{ + free(arr->elems); +} + +static int cmp_kfuncs(const void *pa, const void *pb, void *ctx) +{ + struct btf *btf = ctx; + const struct btf_type *a = *(void **)pa; + const struct btf_type *b = *(void **)pb; + + return strcmp(btf__str_by_offset(btf, a->name_off), + btf__str_by_offset(btf, b->name_off)); +} + +static int dump_btf_kfuncs(struct btf_dump *d, const struct btf *btf) +{ + LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts); + __u32 cnt = btf__type_cnt(btf), i, j; + struct ptr_array fastcalls = {}; + struct ptr_array kfuncs = {}; + int err = 0; + + printf("\n/* BPF kfuncs */\n"); + printf("#ifndef BPF_NO_KFUNC_PROTOTYPES\n"); + + for (i = 1; i < cnt; i++) { + const struct btf_type *t = btf__type_by_id(btf, i); + const struct btf_type *ft; + const char *name; + + if (!btf_is_decl_tag(t)) + continue; + + if (btf_decl_tag(t)->component_idx != -1) + continue; + + ft = btf__type_by_id(btf, t->type); + if (!btf_is_func(ft)) + continue; + + name = btf__name_by_offset(btf, t->name_off); + if (strncmp(name, KFUNC_DECL_TAG, sizeof(KFUNC_DECL_TAG)) == 0) { + err = ptr_array_push(ft, &kfuncs); + if (err) + goto out; + } + + if (strncmp(name, FASTCALL_DECL_TAG, sizeof(FASTCALL_DECL_TAG)) == 0) { + err = ptr_array_push(ft, &fastcalls); + if (err) + goto out; + } + } + + /* Sort kfuncs by name for improved vmlinux.h stability */ + qsort_r(kfuncs.elems, kfuncs.cnt, sizeof(*kfuncs.elems), cmp_kfuncs, (void *)btf); + for (i = 0; i < kfuncs.cnt; i++) { + const struct btf_type *t = kfuncs.elems[i]; + + printf("extern "); + + /* Assume small amount of fastcall kfuncs */ + for (j = 0; j < fastcalls.cnt; j++) { + if (fastcalls.elems[j] == t) { + printf("__bpf_fastcall "); + break; + } + } + + opts.field_name = btf__name_by_offset(btf, t->name_off); + err = btf_dump__emit_type_decl(d, t->type, &opts); + if (err) + goto out; + + printf(" __weak __ksym;\n"); + } + + printf("#endif\n\n"); + +out: + ptr_array_free(&fastcalls); + ptr_array_free(&kfuncs); + return err; +} + +static void __printf(2, 0) btf_dump_printf(void *ctx, + const char *fmt, va_list args) +{ + vfprintf(stdout, fmt, args); +} + +static int btf_type_rank(const struct btf *btf, __u32 index, bool has_name) +{ + const struct btf_type *t = btf__type_by_id(btf, index); + const int kind = btf_kind(t); + const int max_rank = 10; + + if (t->name_off) + has_name = true; + + switch (kind) { + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + return has_name ? 1 : 0; + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + return 2; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + return has_name ? 3 : max_rank; + case BTF_KIND_FUNC_PROTO: + return has_name ? 4 : max_rank; + case BTF_KIND_ARRAY: + if (has_name) + return btf_type_rank(btf, btf_array(t)->type, has_name); + return max_rank; + case BTF_KIND_TYPE_TAG: + case BTF_KIND_CONST: + case BTF_KIND_PTR: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_TYPEDEF: + case BTF_KIND_DECL_TAG: + if (has_name) + return btf_type_rank(btf, t->type, has_name); + return max_rank; + default: + return max_rank; + } +} + +static const char *btf_type_sort_name(const struct btf *btf, __u32 index, bool from_ref) +{ + const struct btf_type *t = btf__type_by_id(btf, index); + + switch (btf_kind(t)) { + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: { + int name_off = t->name_off; + + if (!from_ref && !name_off && btf_vlen(t)) + name_off = btf_kind(t) == BTF_KIND_ENUM64 ? + btf_enum64(t)->name_off : + btf_enum(t)->name_off; + + return btf__name_by_offset(btf, name_off); + } + case BTF_KIND_ARRAY: + return btf_type_sort_name(btf, btf_array(t)->type, true); + case BTF_KIND_TYPE_TAG: + case BTF_KIND_CONST: + case BTF_KIND_PTR: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_TYPEDEF: + case BTF_KIND_DECL_TAG: + return btf_type_sort_name(btf, t->type, true); + default: + return btf__name_by_offset(btf, t->name_off); + } + return NULL; +} + +static __u64 hasher(__u64 hash, __u64 val) +{ + return hash * 31 + val; +} + +static __u64 btf_name_hasher(__u64 hash, const struct btf *btf, __u32 name_off) +{ + if (!name_off) + return hash; + + return hasher(hash, str_hash(btf__name_by_offset(btf, name_off))); +} + +static __u64 btf_type_disambig_hash(const struct btf *btf, __u32 id, bool include_members) +{ + const struct btf_type *t = btf__type_by_id(btf, id); + int i; + size_t hash = 0; + + hash = btf_name_hasher(hash, btf, t->name_off); + + switch (btf_kind(t)) { + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + for (i = 0; i < btf_vlen(t); i++) { + __u32 name_off = btf_is_enum(t) ? + btf_enum(t)[i].name_off : + btf_enum64(t)[i].name_off; + + hash = btf_name_hasher(hash, btf, name_off); + } + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + if (!include_members) + break; + for (i = 0; i < btf_vlen(t); i++) { + const struct btf_member *m = btf_members(t) + i; + + hash = btf_name_hasher(hash, btf, m->name_off); + /* resolve field type's name and hash it as well */ + hash = hasher(hash, btf_type_disambig_hash(btf, m->type, false)); + } + break; + case BTF_KIND_TYPE_TAG: + case BTF_KIND_CONST: + case BTF_KIND_PTR: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_TYPEDEF: + case BTF_KIND_DECL_TAG: + hash = hasher(hash, btf_type_disambig_hash(btf, t->type, include_members)); + break; + case BTF_KIND_ARRAY: { + struct btf_array *arr = btf_array(t); + + hash = hasher(hash, arr->nelems); + hash = hasher(hash, btf_type_disambig_hash(btf, arr->type, include_members)); + break; + } + default: + break; + } + return hash; +} + +static int btf_type_compare(const void *left, const void *right) +{ + const struct sort_datum *d1 = (const struct sort_datum *)left; + const struct sort_datum *d2 = (const struct sort_datum *)right; + int r; + + r = d1->type_rank - d2->type_rank; + r = r ?: strcmp(d1->sort_name, d2->sort_name); + r = r ?: strcmp(d1->own_name, d2->own_name); + if (r) + return r; + + if (d1->disambig_hash != d2->disambig_hash) + return d1->disambig_hash < d2->disambig_hash ? -1 : 1; + + return d1->index - d2->index; +} + +static struct sort_datum *sort_btf_c(const struct btf *btf) +{ + struct sort_datum *datums; + int n; + + n = btf__type_cnt(btf); + datums = malloc(sizeof(struct sort_datum) * n); + if (!datums) + return NULL; + + for (int i = 0; i < n; ++i) { + struct sort_datum *d = datums + i; + const struct btf_type *t = btf__type_by_id(btf, i); + + d->index = i; + d->type_rank = btf_type_rank(btf, i, false); + d->sort_name = btf_type_sort_name(btf, i, false); + d->own_name = btf__name_by_offset(btf, t->name_off); + d->disambig_hash = btf_type_disambig_hash(btf, i, true); + } + + qsort(datums, n, sizeof(struct sort_datum), btf_type_compare); + + return datums; +} + +static int dump_btf_c(const struct btf *btf, + __u32 *root_type_ids, int root_type_cnt, bool sort_dump) +{ + struct sort_datum *datums = NULL; + struct btf_dump *d; + int err = 0, i; + + d = btf_dump__new(btf, btf_dump_printf, NULL, NULL); + if (!d) + return -errno; + + printf("#ifndef __VMLINUX_H__\n"); + printf("#define __VMLINUX_H__\n"); + printf("\n"); + printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n"); + printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n"); + printf("#endif\n\n"); + printf("#ifndef __ksym\n"); + printf("#define __ksym __attribute__((section(\".ksyms\")))\n"); + printf("#endif\n\n"); + printf("#ifndef __weak\n"); + printf("#define __weak __attribute__((weak))\n"); + printf("#endif\n\n"); + printf("#ifndef __bpf_fastcall\n"); + printf("#if __has_attribute(bpf_fastcall)\n"); + printf("#define __bpf_fastcall __attribute__((bpf_fastcall))\n"); + printf("#else\n"); + printf("#define __bpf_fastcall\n"); + printf("#endif\n"); + printf("#endif\n\n"); + + if (root_type_cnt) { + for (i = 0; i < root_type_cnt; i++) { + err = btf_dump__dump_type(d, root_type_ids[i]); + if (err) + goto done; + } + } else { + int cnt = btf__type_cnt(btf); + + if (sort_dump) + datums = sort_btf_c(btf); + for (i = 1; i < cnt; i++) { + int idx = datums ? datums[i].index : i; + + err = btf_dump__dump_type(d, idx); + if (err) + goto done; + } + + err = dump_btf_kfuncs(d, btf); + if (err) + goto done; + } + + printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n"); + printf("#pragma clang attribute pop\n"); + printf("#endif\n"); + printf("\n"); + printf("#endif /* __VMLINUX_H__ */\n"); + +done: + free(datums); + btf_dump__free(d); + return err; +} + +static const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux"; + +static struct btf *get_vmlinux_btf_from_sysfs(void) +{ + struct btf *base; + + base = btf__parse(sysfs_vmlinux, NULL); + if (!base) + p_err("failed to parse vmlinux BTF at '%s': %d\n", + sysfs_vmlinux, -errno); + + return base; +} + +#define BTF_NAME_BUFF_LEN 64 + +static bool btf_is_kernel_module(__u32 btf_id) +{ + struct bpf_btf_info btf_info = {}; + char btf_name[BTF_NAME_BUFF_LEN]; + int btf_fd; + __u32 len; + int err; + + btf_fd = bpf_btf_get_fd_by_id(btf_id); + if (btf_fd < 0) { + p_err("can't get BTF object by id (%u): %s", btf_id, strerror(errno)); + return false; + } + + len = sizeof(btf_info); + btf_info.name = ptr_to_u64(btf_name); + btf_info.name_len = sizeof(btf_name); + err = bpf_btf_get_info_by_fd(btf_fd, &btf_info, &len); + close(btf_fd); + if (err) { + p_err("can't get BTF (ID %u) object info: %s", btf_id, strerror(errno)); + return false; + } + + return btf_info.kernel_btf && strncmp(btf_name, "vmlinux", sizeof(btf_name)) != 0; +} + +static int do_dump(int argc, char **argv) +{ + bool dump_c = false, sort_dump_c = true; + struct btf *btf = NULL, *base = NULL; + __u32 root_type_ids[MAX_ROOT_IDS]; + bool have_id_filtering; + int root_type_cnt = 0; + __u32 btf_id = -1; + const char *src; + int fd = -1; + int err = 0; + int i; + + if (!REQ_ARGS(2)) { + usage(); + return -1; + } + src = GET_ARG(); + if (is_prefix(src, "map")) { + struct bpf_map_info info = {}; + __u32 len = sizeof(info); + + if (!REQ_ARGS(2)) { + usage(); + return -1; + } + + fd = map_parse_fd_and_info(&argc, &argv, &info, &len, + BPF_F_RDONLY); + if (fd < 0) + return -1; + + btf_id = info.btf_id; + if (argc && is_prefix(*argv, "key")) { + root_type_ids[root_type_cnt++] = info.btf_key_type_id; + NEXT_ARG(); + } else if (argc && is_prefix(*argv, "value")) { + root_type_ids[root_type_cnt++] = info.btf_value_type_id; + NEXT_ARG(); + } else if (argc && is_prefix(*argv, "all")) { + NEXT_ARG(); + } else if (argc && is_prefix(*argv, "kv")) { + root_type_ids[root_type_cnt++] = info.btf_key_type_id; + root_type_ids[root_type_cnt++] = info.btf_value_type_id; + NEXT_ARG(); + } else { + root_type_ids[root_type_cnt++] = info.btf_key_type_id; + root_type_ids[root_type_cnt++] = info.btf_value_type_id; + } + } else if (is_prefix(src, "prog")) { + struct bpf_prog_info info = {}; + __u32 len = sizeof(info); + + if (!REQ_ARGS(2)) { + usage(); + return -1; + } + + fd = prog_parse_fd(&argc, &argv); + if (fd < 0) + return -1; + + err = bpf_prog_get_info_by_fd(fd, &info, &len); + if (err) { + p_err("can't get prog info: %s", strerror(errno)); + goto done; + } + + btf_id = info.btf_id; + } else if (is_prefix(src, "id")) { + char *endptr; + + btf_id = strtoul(*argv, &endptr, 0); + if (*endptr) { + p_err("can't parse %s as ID", *argv); + return -1; + } + NEXT_ARG(); + } else if (is_prefix(src, "file")) { + const char sysfs_prefix[] = "/sys/kernel/btf/"; + + if (!base_btf && + strncmp(*argv, sysfs_prefix, sizeof(sysfs_prefix) - 1) == 0 && + strcmp(*argv, sysfs_vmlinux) != 0) + base = get_vmlinux_btf_from_sysfs(); + + btf = btf__parse_split(*argv, base ?: base_btf); + if (!btf) { + err = -errno; + p_err("failed to load BTF from %s: %s", + *argv, strerror(errno)); + goto done; + } + NEXT_ARG(); + } else { + err = -1; + p_err("unrecognized BTF source specifier: '%s'", src); + goto done; + } + + have_id_filtering = !!root_type_cnt; + + while (argc) { + if (is_prefix(*argv, "format")) { + NEXT_ARG(); + if (argc < 1) { + p_err("expecting value for 'format' option\n"); + err = -EINVAL; + goto done; + } + if (strcmp(*argv, "c") == 0) { + dump_c = true; + } else if (strcmp(*argv, "raw") == 0) { + dump_c = false; + } else { + p_err("unrecognized format specifier: '%s', possible values: raw, c", + *argv); + err = -EINVAL; + goto done; + } + NEXT_ARG(); + } else if (is_prefix(*argv, "root_id")) { + __u32 root_id; + char *end; + + if (have_id_filtering) { + p_err("cannot use root_id with other type filtering"); + err = -EINVAL; + goto done; + } else if (root_type_cnt == MAX_ROOT_IDS) { + p_err("only %d root_id are supported", MAX_ROOT_IDS); + err = -E2BIG; + goto done; + } + + NEXT_ARG(); + root_id = strtoul(*argv, &end, 0); + if (*end) { + err = -1; + p_err("can't parse %s as root ID", *argv); + goto done; + } + for (i = 0; i < root_type_cnt; i++) { + if (root_type_ids[i] == root_id) { + err = -EINVAL; + p_err("duplicate root_id %u supplied", root_id); + goto done; + } + } + root_type_ids[root_type_cnt++] = root_id; + NEXT_ARG(); + } else if (is_prefix(*argv, "unsorted")) { + sort_dump_c = false; + NEXT_ARG(); + } else { + p_err("unrecognized option: '%s'", *argv); + err = -EINVAL; + goto done; + } + } + + if (!btf) { + if (!base_btf && btf_is_kernel_module(btf_id)) { + p_info("Warning: valid base BTF was not specified with -B option, falling back to standard base BTF (%s)", + sysfs_vmlinux); + base_btf = get_vmlinux_btf_from_sysfs(); + } + + btf = btf__load_from_kernel_by_id_split(btf_id, base_btf); + if (!btf) { + err = -errno; + p_err("get btf by id (%u): %s", btf_id, strerror(errno)); + goto done; + } + } + + /* Invalid root IDs causes half emitted boilerplate and then unclean + * exit. It's an ugly user experience, so handle common error here. + */ + for (i = 0; i < root_type_cnt; i++) { + if (root_type_ids[i] >= btf__type_cnt(btf)) { + err = -EINVAL; + p_err("invalid root ID: %u", root_type_ids[i]); + goto done; + } + } + + if (dump_c) { + if (json_output) { + p_err("JSON output for C-syntax dump is not supported"); + err = -ENOTSUP; + goto done; + } + err = dump_btf_c(btf, root_type_ids, root_type_cnt, sort_dump_c); + } else { + err = dump_btf_raw(btf, root_type_ids, root_type_cnt); + } + +done: + close(fd); + btf__free(btf); + btf__free(base); + return err; +} + +static int btf_parse_fd(int *argc, char ***argv) +{ + unsigned int id; + char *endptr; + int fd; + + if (!is_prefix(*argv[0], "id")) { + p_err("expected 'id', got: '%s'?", **argv); + return -1; + } + NEXT_ARGP(); + + id = strtoul(**argv, &endptr, 0); + if (*endptr) { + p_err("can't parse %s as ID", **argv); + return -1; + } + NEXT_ARGP(); + + fd = bpf_btf_get_fd_by_id(id); + if (fd < 0) + p_err("can't get BTF object by id (%u): %s", + id, strerror(errno)); + + return fd; +} + +static int +build_btf_type_table(struct hashmap *tab, enum bpf_obj_type type, + void *info, __u32 *len) +{ + static const char * const names[] = { + [BPF_OBJ_UNKNOWN] = "unknown", + [BPF_OBJ_PROG] = "prog", + [BPF_OBJ_MAP] = "map", + }; + LIBBPF_OPTS(bpf_get_fd_by_id_opts, opts_ro); + __u32 btf_id, id = 0; + int err; + int fd; + + opts_ro.open_flags = BPF_F_RDONLY; + + while (true) { + switch (type) { + case BPF_OBJ_PROG: + err = bpf_prog_get_next_id(id, &id); + break; + case BPF_OBJ_MAP: + err = bpf_map_get_next_id(id, &id); + break; + default: + err = -1; + p_err("unexpected object type: %u", type); + goto err_free; + } + if (err) { + if (errno == ENOENT) { + err = 0; + break; + } + p_err("can't get next %s: %s%s", names[type], + strerror(errno), + errno == EINVAL ? " -- kernel too old?" : ""); + goto err_free; + } + + switch (type) { + case BPF_OBJ_PROG: + fd = bpf_prog_get_fd_by_id(id); + break; + case BPF_OBJ_MAP: + fd = bpf_map_get_fd_by_id_opts(id, &opts_ro); + break; + default: + err = -1; + p_err("unexpected object type: %u", type); + goto err_free; + } + if (fd < 0) { + if (errno == ENOENT) + continue; + p_err("can't get %s by id (%u): %s", names[type], id, + strerror(errno)); + err = -1; + goto err_free; + } + + memset(info, 0, *len); + if (type == BPF_OBJ_PROG) + err = bpf_prog_get_info_by_fd(fd, info, len); + else + err = bpf_map_get_info_by_fd(fd, info, len); + close(fd); + if (err) { + p_err("can't get %s info: %s", names[type], + strerror(errno)); + goto err_free; + } + + switch (type) { + case BPF_OBJ_PROG: + btf_id = ((struct bpf_prog_info *)info)->btf_id; + break; + case BPF_OBJ_MAP: + btf_id = ((struct bpf_map_info *)info)->btf_id; + break; + default: + err = -1; + p_err("unexpected object type: %u", type); + goto err_free; + } + if (!btf_id) + continue; + + err = hashmap__append(tab, btf_id, id); + if (err) { + p_err("failed to append entry to hashmap for BTF ID %u, object ID %u: %s", + btf_id, id, strerror(-err)); + goto err_free; + } + } + + return 0; + +err_free: + hashmap__free(tab); + return err; +} + +static int +build_btf_tables(struct hashmap *btf_prog_table, + struct hashmap *btf_map_table) +{ + struct bpf_prog_info prog_info; + __u32 prog_len = sizeof(prog_info); + struct bpf_map_info map_info; + __u32 map_len = sizeof(map_info); + int err = 0; + + err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info, + &prog_len); + if (err) + return err; + + err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info, + &map_len); + if (err) { + hashmap__free(btf_prog_table); + return err; + } + + return 0; +} + +static void +show_btf_plain(struct bpf_btf_info *info, int fd, + struct hashmap *btf_prog_table, + struct hashmap *btf_map_table) +{ + struct hashmap_entry *entry; + const char *name = u64_to_ptr(info->name); + int n; + + printf("%u: ", info->id); + if (info->kernel_btf) + printf("name [%s] ", name); + else if (name && name[0]) + printf("name %s ", name); + else + printf("name <anon> "); + printf("size %uB", info->btf_size); + + n = 0; + hashmap__for_each_key_entry(btf_prog_table, entry, info->id) { + printf("%s%lu", n++ == 0 ? " prog_ids " : ",", (unsigned long)entry->value); + } + + n = 0; + hashmap__for_each_key_entry(btf_map_table, entry, info->id) { + printf("%s%lu", n++ == 0 ? " map_ids " : ",", (unsigned long)entry->value); + } + + emit_obj_refs_plain(refs_table, info->id, "\n\tpids "); + + printf("\n"); +} + +static void +show_btf_json(struct bpf_btf_info *info, int fd, + struct hashmap *btf_prog_table, + struct hashmap *btf_map_table) +{ + struct hashmap_entry *entry; + const char *name = u64_to_ptr(info->name); + + jsonw_start_object(json_wtr); /* btf object */ + jsonw_uint_field(json_wtr, "id", info->id); + jsonw_uint_field(json_wtr, "size", info->btf_size); + + jsonw_name(json_wtr, "prog_ids"); + jsonw_start_array(json_wtr); /* prog_ids */ + hashmap__for_each_key_entry(btf_prog_table, entry, info->id) { + jsonw_uint(json_wtr, entry->value); + } + jsonw_end_array(json_wtr); /* prog_ids */ + + jsonw_name(json_wtr, "map_ids"); + jsonw_start_array(json_wtr); /* map_ids */ + hashmap__for_each_key_entry(btf_map_table, entry, info->id) { + jsonw_uint(json_wtr, entry->value); + } + jsonw_end_array(json_wtr); /* map_ids */ + + emit_obj_refs_json(refs_table, info->id, json_wtr); /* pids */ + + jsonw_bool_field(json_wtr, "kernel", info->kernel_btf); + + if (name && name[0]) + jsonw_string_field(json_wtr, "name", name); + + jsonw_end_object(json_wtr); /* btf object */ +} + +static int +show_btf(int fd, struct hashmap *btf_prog_table, + struct hashmap *btf_map_table) +{ + struct bpf_btf_info info; + __u32 len = sizeof(info); + char name[64]; + int err; + + memset(&info, 0, sizeof(info)); + err = bpf_btf_get_info_by_fd(fd, &info, &len); + if (err) { + p_err("can't get BTF object info: %s", strerror(errno)); + return -1; + } + /* if kernel support emitting BTF object name, pass name pointer */ + if (info.name_len) { + memset(&info, 0, sizeof(info)); + info.name_len = sizeof(name); + info.name = ptr_to_u64(name); + len = sizeof(info); + + err = bpf_btf_get_info_by_fd(fd, &info, &len); + if (err) { + p_err("can't get BTF object info: %s", strerror(errno)); + return -1; + } + } + + if (json_output) + show_btf_json(&info, fd, btf_prog_table, btf_map_table); + else + show_btf_plain(&info, fd, btf_prog_table, btf_map_table); + + return 0; +} + +static int do_show(int argc, char **argv) +{ + struct hashmap *btf_prog_table; + struct hashmap *btf_map_table; + int err, fd = -1; + __u32 id = 0; + + if (argc == 2) { + fd = btf_parse_fd(&argc, &argv); + if (fd < 0) + return -1; + } + + if (argc) { + if (fd >= 0) + close(fd); + return BAD_ARG(); + } + + btf_prog_table = hashmap__new(hash_fn_for_key_as_id, + equal_fn_for_key_as_id, NULL); + btf_map_table = hashmap__new(hash_fn_for_key_as_id, + equal_fn_for_key_as_id, NULL); + if (IS_ERR(btf_prog_table) || IS_ERR(btf_map_table)) { + hashmap__free(btf_prog_table); + hashmap__free(btf_map_table); + if (fd >= 0) + close(fd); + p_err("failed to create hashmap for object references"); + return -1; + } + err = build_btf_tables(btf_prog_table, btf_map_table); + if (err) { + if (fd >= 0) + close(fd); + return err; + } + build_obj_refs_table(&refs_table, BPF_OBJ_BTF); + + if (fd >= 0) { + err = show_btf(fd, btf_prog_table, btf_map_table); + close(fd); + goto exit_free; + } + + if (json_output) + jsonw_start_array(json_wtr); /* root array */ + + while (true) { + err = bpf_btf_get_next_id(id, &id); + if (err) { + if (errno == ENOENT) { + err = 0; + break; + } + p_err("can't get next BTF object: %s%s", + strerror(errno), + errno == EINVAL ? " -- kernel too old?" : ""); + err = -1; + break; + } + + fd = bpf_btf_get_fd_by_id(id); + if (fd < 0) { + if (errno == ENOENT) + continue; + p_err("can't get BTF object by id (%u): %s", + id, strerror(errno)); + err = -1; + break; + } + + err = show_btf(fd, btf_prog_table, btf_map_table); + close(fd); + if (err) + break; + } + + if (json_output) + jsonw_end_array(json_wtr); /* root array */ + +exit_free: + hashmap__free(btf_prog_table); + hashmap__free(btf_map_table); + delete_obj_refs_table(refs_table); + + return err; +} + +static int do_help(int argc, char **argv) +{ + if (json_output) { + jsonw_null(json_wtr); + return 0; + } + + fprintf(stderr, + "Usage: %1$s %2$s { show | list } [id BTF_ID]\n" + " %1$s %2$s dump BTF_SRC [format FORMAT] [root_id ROOT_ID]\n" + " %1$s %2$s help\n" + "\n" + " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n" + " FORMAT := { raw | c [unsorted] }\n" + " " HELP_SPEC_MAP "\n" + " " HELP_SPEC_PROGRAM "\n" + " " HELP_SPEC_OPTIONS " |\n" + " {-B|--base-btf} }\n" + "", + bin_name, "btf"); + + return 0; +} + +static const struct cmd cmds[] = { + { "show", do_show }, + { "list", do_show }, + { "help", do_help }, + { "dump", do_dump }, + { 0 } +}; + +int do_btf(int argc, char **argv) +{ + return cmd_select(cmds, argc, argv, do_help); +} |