2799 lines
74 KiB
C
2799 lines
74 KiB
C
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
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/* Copyright (c) 2018 Facebook */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include <linux/err.h>
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#include <linux/btf.h>
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#include "btf.h"
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#include "bpf.h"
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#include "libbpf.h"
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#include "libbpf_util.h"
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#define max(a, b) ((a) > (b) ? (a) : (b))
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#define min(a, b) ((a) < (b) ? (a) : (b))
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#define BTF_MAX_NR_TYPES 0x7fffffff
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#define BTF_MAX_STR_OFFSET 0x7fffffff
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#define IS_MODIFIER(k) (((k) == BTF_KIND_TYPEDEF) || \
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((k) == BTF_KIND_VOLATILE) || \
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((k) == BTF_KIND_CONST) || \
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((k) == BTF_KIND_RESTRICT))
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#define IS_VAR(k) ((k) == BTF_KIND_VAR)
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static struct btf_type btf_void;
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struct btf {
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union {
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struct btf_header *hdr;
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void *data;
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};
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struct btf_type **types;
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const char *strings;
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void *nohdr_data;
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__u32 nr_types;
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__u32 types_size;
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__u32 data_size;
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int fd;
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};
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struct btf_ext_info {
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/*
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* info points to the individual info section (e.g. func_info and
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* line_info) from the .BTF.ext. It does not include the __u32 rec_size.
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*/
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void *info;
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__u32 rec_size;
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__u32 len;
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};
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struct btf_ext {
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union {
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struct btf_ext_header *hdr;
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void *data;
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};
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struct btf_ext_info func_info;
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struct btf_ext_info line_info;
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__u32 data_size;
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};
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struct btf_ext_info_sec {
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__u32 sec_name_off;
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__u32 num_info;
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/* Followed by num_info * record_size number of bytes */
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__u8 data[0];
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};
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/* The minimum bpf_func_info checked by the loader */
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struct bpf_func_info_min {
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__u32 insn_off;
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__u32 type_id;
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};
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/* The minimum bpf_line_info checked by the loader */
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struct bpf_line_info_min {
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__u32 insn_off;
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__u32 file_name_off;
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__u32 line_off;
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__u32 line_col;
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};
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static inline __u64 ptr_to_u64(const void *ptr)
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{
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return (__u64) (unsigned long) ptr;
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}
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static int btf_add_type(struct btf *btf, struct btf_type *t)
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{
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if (btf->types_size - btf->nr_types < 2) {
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struct btf_type **new_types;
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__u32 expand_by, new_size;
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if (btf->types_size == BTF_MAX_NR_TYPES)
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return -E2BIG;
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expand_by = max(btf->types_size >> 2, 16);
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new_size = min(BTF_MAX_NR_TYPES, btf->types_size + expand_by);
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new_types = realloc(btf->types, sizeof(*new_types) * new_size);
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if (!new_types)
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return -ENOMEM;
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if (btf->nr_types == 0)
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new_types[0] = &btf_void;
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btf->types = new_types;
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btf->types_size = new_size;
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}
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btf->types[++(btf->nr_types)] = t;
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return 0;
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}
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static int btf_parse_hdr(struct btf *btf)
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{
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const struct btf_header *hdr = btf->hdr;
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__u32 meta_left;
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if (btf->data_size < sizeof(struct btf_header)) {
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pr_debug("BTF header not found\n");
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return -EINVAL;
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}
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if (hdr->magic != BTF_MAGIC) {
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pr_debug("Invalid BTF magic:%x\n", hdr->magic);
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return -EINVAL;
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}
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if (hdr->version != BTF_VERSION) {
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pr_debug("Unsupported BTF version:%u\n", hdr->version);
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return -ENOTSUP;
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}
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if (hdr->flags) {
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pr_debug("Unsupported BTF flags:%x\n", hdr->flags);
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return -ENOTSUP;
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}
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meta_left = btf->data_size - sizeof(*hdr);
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if (!meta_left) {
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pr_debug("BTF has no data\n");
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return -EINVAL;
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}
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if (meta_left < hdr->type_off) {
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pr_debug("Invalid BTF type section offset:%u\n", hdr->type_off);
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return -EINVAL;
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}
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if (meta_left < hdr->str_off) {
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pr_debug("Invalid BTF string section offset:%u\n", hdr->str_off);
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return -EINVAL;
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}
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if (hdr->type_off >= hdr->str_off) {
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pr_debug("BTF type section offset >= string section offset. No type?\n");
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return -EINVAL;
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}
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if (hdr->type_off & 0x02) {
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pr_debug("BTF type section is not aligned to 4 bytes\n");
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return -EINVAL;
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}
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btf->nohdr_data = btf->hdr + 1;
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return 0;
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}
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static int btf_parse_str_sec(struct btf *btf)
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{
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const struct btf_header *hdr = btf->hdr;
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const char *start = btf->nohdr_data + hdr->str_off;
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const char *end = start + btf->hdr->str_len;
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if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET ||
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start[0] || end[-1]) {
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pr_debug("Invalid BTF string section\n");
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return -EINVAL;
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}
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btf->strings = start;
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return 0;
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}
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static int btf_type_size(struct btf_type *t)
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{
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int base_size = sizeof(struct btf_type);
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__u16 vlen = BTF_INFO_VLEN(t->info);
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switch (BTF_INFO_KIND(t->info)) {
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case BTF_KIND_FWD:
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case BTF_KIND_CONST:
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case BTF_KIND_VOLATILE:
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case BTF_KIND_RESTRICT:
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case BTF_KIND_PTR:
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case BTF_KIND_TYPEDEF:
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case BTF_KIND_FUNC:
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return base_size;
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case BTF_KIND_INT:
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return base_size + sizeof(__u32);
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case BTF_KIND_ENUM:
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return base_size + vlen * sizeof(struct btf_enum);
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case BTF_KIND_ARRAY:
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return base_size + sizeof(struct btf_array);
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case BTF_KIND_STRUCT:
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case BTF_KIND_UNION:
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return base_size + vlen * sizeof(struct btf_member);
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case BTF_KIND_FUNC_PROTO:
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return base_size + vlen * sizeof(struct btf_param);
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case BTF_KIND_VAR:
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return base_size + sizeof(struct btf_var);
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case BTF_KIND_DATASEC:
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return base_size + vlen * sizeof(struct btf_var_secinfo);
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default:
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pr_debug("Unsupported BTF_KIND:%u\n", BTF_INFO_KIND(t->info));
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return -EINVAL;
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}
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}
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static int btf_parse_type_sec(struct btf *btf)
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{
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struct btf_header *hdr = btf->hdr;
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void *nohdr_data = btf->nohdr_data;
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void *next_type = nohdr_data + hdr->type_off;
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void *end_type = nohdr_data + hdr->str_off;
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while (next_type < end_type) {
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struct btf_type *t = next_type;
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int type_size;
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int err;
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type_size = btf_type_size(t);
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if (type_size < 0)
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return type_size;
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next_type += type_size;
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err = btf_add_type(btf, t);
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if (err)
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return err;
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}
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return 0;
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}
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__u32 btf__get_nr_types(const struct btf *btf)
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{
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return btf->nr_types;
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}
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const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id)
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{
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if (type_id > btf->nr_types)
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return NULL;
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return btf->types[type_id];
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}
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static bool btf_type_is_void(const struct btf_type *t)
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{
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return t == &btf_void || BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
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}
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static bool btf_type_is_void_or_null(const struct btf_type *t)
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{
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return !t || btf_type_is_void(t);
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}
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#define MAX_RESOLVE_DEPTH 32
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__s64 btf__resolve_size(const struct btf *btf, __u32 type_id)
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{
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const struct btf_array *array;
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const struct btf_type *t;
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__u32 nelems = 1;
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__s64 size = -1;
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int i;
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t = btf__type_by_id(btf, type_id);
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for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t);
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i++) {
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switch (BTF_INFO_KIND(t->info)) {
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case BTF_KIND_INT:
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case BTF_KIND_STRUCT:
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case BTF_KIND_UNION:
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case BTF_KIND_ENUM:
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case BTF_KIND_DATASEC:
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size = t->size;
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goto done;
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case BTF_KIND_PTR:
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size = sizeof(void *);
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goto done;
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case BTF_KIND_TYPEDEF:
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case BTF_KIND_VOLATILE:
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case BTF_KIND_CONST:
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case BTF_KIND_RESTRICT:
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case BTF_KIND_VAR:
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type_id = t->type;
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break;
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case BTF_KIND_ARRAY:
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array = (const struct btf_array *)(t + 1);
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if (nelems && array->nelems > UINT32_MAX / nelems)
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return -E2BIG;
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nelems *= array->nelems;
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type_id = array->type;
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break;
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default:
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return -EINVAL;
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}
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t = btf__type_by_id(btf, type_id);
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}
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if (size < 0)
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return -EINVAL;
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done:
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if (nelems && size > UINT32_MAX / nelems)
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return -E2BIG;
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return nelems * size;
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}
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int btf__resolve_type(const struct btf *btf, __u32 type_id)
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{
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const struct btf_type *t;
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int depth = 0;
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t = btf__type_by_id(btf, type_id);
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while (depth < MAX_RESOLVE_DEPTH &&
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!btf_type_is_void_or_null(t) &&
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(IS_MODIFIER(BTF_INFO_KIND(t->info)) ||
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IS_VAR(BTF_INFO_KIND(t->info)))) {
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type_id = t->type;
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t = btf__type_by_id(btf, type_id);
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depth++;
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}
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if (depth == MAX_RESOLVE_DEPTH || btf_type_is_void_or_null(t))
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return -EINVAL;
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return type_id;
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}
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__s32 btf__find_by_name(const struct btf *btf, const char *type_name)
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{
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__u32 i;
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if (!strcmp(type_name, "void"))
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return 0;
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for (i = 1; i <= btf->nr_types; i++) {
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const struct btf_type *t = btf->types[i];
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const char *name = btf__name_by_offset(btf, t->name_off);
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if (name && !strcmp(type_name, name))
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return i;
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}
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return -ENOENT;
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}
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void btf__free(struct btf *btf)
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{
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if (!btf)
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return;
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if (btf->fd != -1)
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close(btf->fd);
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free(btf->data);
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free(btf->types);
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free(btf);
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}
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struct btf *btf__new(__u8 *data, __u32 size)
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{
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struct btf *btf;
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int err;
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btf = calloc(1, sizeof(struct btf));
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if (!btf)
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return ERR_PTR(-ENOMEM);
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btf->fd = -1;
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btf->data = malloc(size);
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if (!btf->data) {
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err = -ENOMEM;
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goto done;
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}
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memcpy(btf->data, data, size);
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btf->data_size = size;
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err = btf_parse_hdr(btf);
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if (err)
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goto done;
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err = btf_parse_str_sec(btf);
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if (err)
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goto done;
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err = btf_parse_type_sec(btf);
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done:
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if (err) {
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btf__free(btf);
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return ERR_PTR(err);
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}
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return btf;
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}
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static int compare_vsi_off(const void *_a, const void *_b)
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{
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const struct btf_var_secinfo *a = _a;
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const struct btf_var_secinfo *b = _b;
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return a->offset - b->offset;
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}
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static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf,
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struct btf_type *t)
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{
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__u32 size = 0, off = 0, i, vars = BTF_INFO_VLEN(t->info);
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const char *name = btf__name_by_offset(btf, t->name_off);
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const struct btf_type *t_var;
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struct btf_var_secinfo *vsi;
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struct btf_var *var;
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int ret;
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if (!name) {
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pr_debug("No name found in string section for DATASEC kind.\n");
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return -ENOENT;
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}
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ret = bpf_object__section_size(obj, name, &size);
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if (ret || !size || (t->size && t->size != size)) {
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pr_debug("Invalid size for section %s: %u bytes\n", name, size);
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return -ENOENT;
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}
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t->size = size;
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for (i = 0, vsi = (struct btf_var_secinfo *)(t + 1);
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i < vars; i++, vsi++) {
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t_var = btf__type_by_id(btf, vsi->type);
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var = (struct btf_var *)(t_var + 1);
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if (BTF_INFO_KIND(t_var->info) != BTF_KIND_VAR) {
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pr_debug("Non-VAR type seen in section %s\n", name);
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return -EINVAL;
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}
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if (var->linkage == BTF_VAR_STATIC)
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continue;
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name = btf__name_by_offset(btf, t_var->name_off);
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if (!name) {
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pr_debug("No name found in string section for VAR kind\n");
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return -ENOENT;
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}
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ret = bpf_object__variable_offset(obj, name, &off);
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if (ret) {
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pr_debug("No offset found in symbol table for VAR %s\n", name);
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return -ENOENT;
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}
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vsi->offset = off;
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}
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qsort(t + 1, vars, sizeof(*vsi), compare_vsi_off);
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return 0;
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}
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int btf__finalize_data(struct bpf_object *obj, struct btf *btf)
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{
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int err = 0;
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__u32 i;
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for (i = 1; i <= btf->nr_types; i++) {
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struct btf_type *t = btf->types[i];
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|
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/* Loader needs to fix up some of the things compiler
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* couldn't get its hands on while emitting BTF. This
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* is section size and global variable offset. We use
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* the info from the ELF itself for this purpose.
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*/
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if (BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC) {
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err = btf_fixup_datasec(obj, btf, t);
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if (err)
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break;
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}
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}
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return err;
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}
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int btf__load(struct btf *btf)
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{
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__u32 log_buf_size = BPF_LOG_BUF_SIZE;
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char *log_buf = NULL;
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int err = 0;
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if (btf->fd >= 0)
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return -EEXIST;
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log_buf = malloc(log_buf_size);
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if (!log_buf)
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return -ENOMEM;
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|
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*log_buf = 0;
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|
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btf->fd = bpf_load_btf(btf->data, btf->data_size,
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log_buf, log_buf_size, false);
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if (btf->fd < 0) {
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err = -errno;
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pr_warning("Error loading BTF: %s(%d)\n", strerror(errno), errno);
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if (*log_buf)
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pr_warning("%s\n", log_buf);
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goto done;
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}
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done:
|
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free(log_buf);
|
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return err;
|
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}
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|
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int btf__fd(const struct btf *btf)
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|
{
|
|
return btf->fd;
|
|
}
|
|
|
|
const void *btf__get_raw_data(const struct btf *btf, __u32 *size)
|
|
{
|
|
*size = btf->data_size;
|
|
return btf->data;
|
|
}
|
|
|
|
const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
|
|
{
|
|
if (offset < btf->hdr->str_len)
|
|
return &btf->strings[offset];
|
|
else
|
|
return NULL;
|
|
}
|
|
|
|
int btf__get_from_id(__u32 id, struct btf **btf)
|
|
{
|
|
struct bpf_btf_info btf_info = { 0 };
|
|
__u32 len = sizeof(btf_info);
|
|
__u32 last_size;
|
|
int btf_fd;
|
|
void *ptr;
|
|
int err;
|
|
|
|
err = 0;
|
|
*btf = NULL;
|
|
btf_fd = bpf_btf_get_fd_by_id(id);
|
|
if (btf_fd < 0)
|
|
return 0;
|
|
|
|
/* we won't know btf_size until we call bpf_obj_get_info_by_fd(). so
|
|
* let's start with a sane default - 4KiB here - and resize it only if
|
|
* bpf_obj_get_info_by_fd() needs a bigger buffer.
|
|
*/
|
|
btf_info.btf_size = 4096;
|
|
last_size = btf_info.btf_size;
|
|
ptr = malloc(last_size);
|
|
if (!ptr) {
|
|
err = -ENOMEM;
|
|
goto exit_free;
|
|
}
|
|
|
|
memset(ptr, 0, last_size);
|
|
btf_info.btf = ptr_to_u64(ptr);
|
|
err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
|
|
|
|
if (!err && btf_info.btf_size > last_size) {
|
|
void *temp_ptr;
|
|
|
|
last_size = btf_info.btf_size;
|
|
temp_ptr = realloc(ptr, last_size);
|
|
if (!temp_ptr) {
|
|
err = -ENOMEM;
|
|
goto exit_free;
|
|
}
|
|
ptr = temp_ptr;
|
|
memset(ptr, 0, last_size);
|
|
btf_info.btf = ptr_to_u64(ptr);
|
|
err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
|
|
}
|
|
|
|
if (err || btf_info.btf_size > last_size) {
|
|
err = errno;
|
|
goto exit_free;
|
|
}
|
|
|
|
*btf = btf__new((__u8 *)(long)btf_info.btf, btf_info.btf_size);
|
|
if (IS_ERR(*btf)) {
|
|
err = PTR_ERR(*btf);
|
|
*btf = NULL;
|
|
}
|
|
|
|
exit_free:
|
|
close(btf_fd);
|
|
free(ptr);
|
|
|
|
return err;
|
|
}
|
|
|
|
int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
|
|
__u32 expected_key_size, __u32 expected_value_size,
|
|
__u32 *key_type_id, __u32 *value_type_id)
|
|
{
|
|
const struct btf_type *container_type;
|
|
const struct btf_member *key, *value;
|
|
const size_t max_name = 256;
|
|
char container_name[max_name];
|
|
__s64 key_size, value_size;
|
|
__s32 container_id;
|
|
|
|
if (snprintf(container_name, max_name, "____btf_map_%s", map_name) ==
|
|
max_name) {
|
|
pr_warning("map:%s length of '____btf_map_%s' is too long\n",
|
|
map_name, map_name);
|
|
return -EINVAL;
|
|
}
|
|
|
|
container_id = btf__find_by_name(btf, container_name);
|
|
if (container_id < 0) {
|
|
pr_debug("map:%s container_name:%s cannot be found in BTF. Missing BPF_ANNOTATE_KV_PAIR?\n",
|
|
map_name, container_name);
|
|
return container_id;
|
|
}
|
|
|
|
container_type = btf__type_by_id(btf, container_id);
|
|
if (!container_type) {
|
|
pr_warning("map:%s cannot find BTF type for container_id:%u\n",
|
|
map_name, container_id);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (BTF_INFO_KIND(container_type->info) != BTF_KIND_STRUCT ||
|
|
BTF_INFO_VLEN(container_type->info) < 2) {
|
|
pr_warning("map:%s container_name:%s is an invalid container struct\n",
|
|
map_name, container_name);
|
|
return -EINVAL;
|
|
}
|
|
|
|
key = (struct btf_member *)(container_type + 1);
|
|
value = key + 1;
|
|
|
|
key_size = btf__resolve_size(btf, key->type);
|
|
if (key_size < 0) {
|
|
pr_warning("map:%s invalid BTF key_type_size\n", map_name);
|
|
return key_size;
|
|
}
|
|
|
|
if (expected_key_size != key_size) {
|
|
pr_warning("map:%s btf_key_type_size:%u != map_def_key_size:%u\n",
|
|
map_name, (__u32)key_size, expected_key_size);
|
|
return -EINVAL;
|
|
}
|
|
|
|
value_size = btf__resolve_size(btf, value->type);
|
|
if (value_size < 0) {
|
|
pr_warning("map:%s invalid BTF value_type_size\n", map_name);
|
|
return value_size;
|
|
}
|
|
|
|
if (expected_value_size != value_size) {
|
|
pr_warning("map:%s btf_value_type_size:%u != map_def_value_size:%u\n",
|
|
map_name, (__u32)value_size, expected_value_size);
|
|
return -EINVAL;
|
|
}
|
|
|
|
*key_type_id = key->type;
|
|
*value_type_id = value->type;
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct btf_ext_sec_setup_param {
|
|
__u32 off;
|
|
__u32 len;
|
|
__u32 min_rec_size;
|
|
struct btf_ext_info *ext_info;
|
|
const char *desc;
|
|
};
|
|
|
|
static int btf_ext_setup_info(struct btf_ext *btf_ext,
|
|
struct btf_ext_sec_setup_param *ext_sec)
|
|
{
|
|
const struct btf_ext_info_sec *sinfo;
|
|
struct btf_ext_info *ext_info;
|
|
__u32 info_left, record_size;
|
|
/* The start of the info sec (including the __u32 record_size). */
|
|
void *info;
|
|
|
|
if (ext_sec->off & 0x03) {
|
|
pr_debug(".BTF.ext %s section is not aligned to 4 bytes\n",
|
|
ext_sec->desc);
|
|
return -EINVAL;
|
|
}
|
|
|
|
info = btf_ext->data + btf_ext->hdr->hdr_len + ext_sec->off;
|
|
info_left = ext_sec->len;
|
|
|
|
if (btf_ext->data + btf_ext->data_size < info + ext_sec->len) {
|
|
pr_debug("%s section (off:%u len:%u) is beyond the end of the ELF section .BTF.ext\n",
|
|
ext_sec->desc, ext_sec->off, ext_sec->len);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* At least a record size */
|
|
if (info_left < sizeof(__u32)) {
|
|
pr_debug(".BTF.ext %s record size not found\n", ext_sec->desc);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* The record size needs to meet the minimum standard */
|
|
record_size = *(__u32 *)info;
|
|
if (record_size < ext_sec->min_rec_size ||
|
|
record_size & 0x03) {
|
|
pr_debug("%s section in .BTF.ext has invalid record size %u\n",
|
|
ext_sec->desc, record_size);
|
|
return -EINVAL;
|
|
}
|
|
|
|
sinfo = info + sizeof(__u32);
|
|
info_left -= sizeof(__u32);
|
|
|
|
/* If no records, return failure now so .BTF.ext won't be used. */
|
|
if (!info_left) {
|
|
pr_debug("%s section in .BTF.ext has no records", ext_sec->desc);
|
|
return -EINVAL;
|
|
}
|
|
|
|
while (info_left) {
|
|
unsigned int sec_hdrlen = sizeof(struct btf_ext_info_sec);
|
|
__u64 total_record_size;
|
|
__u32 num_records;
|
|
|
|
if (info_left < sec_hdrlen) {
|
|
pr_debug("%s section header is not found in .BTF.ext\n",
|
|
ext_sec->desc);
|
|
return -EINVAL;
|
|
}
|
|
|
|
num_records = sinfo->num_info;
|
|
if (num_records == 0) {
|
|
pr_debug("%s section has incorrect num_records in .BTF.ext\n",
|
|
ext_sec->desc);
|
|
return -EINVAL;
|
|
}
|
|
|
|
total_record_size = sec_hdrlen +
|
|
(__u64)num_records * record_size;
|
|
if (info_left < total_record_size) {
|
|
pr_debug("%s section has incorrect num_records in .BTF.ext\n",
|
|
ext_sec->desc);
|
|
return -EINVAL;
|
|
}
|
|
|
|
info_left -= total_record_size;
|
|
sinfo = (void *)sinfo + total_record_size;
|
|
}
|
|
|
|
ext_info = ext_sec->ext_info;
|
|
ext_info->len = ext_sec->len - sizeof(__u32);
|
|
ext_info->rec_size = record_size;
|
|
ext_info->info = info + sizeof(__u32);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int btf_ext_setup_func_info(struct btf_ext *btf_ext)
|
|
{
|
|
struct btf_ext_sec_setup_param param = {
|
|
.off = btf_ext->hdr->func_info_off,
|
|
.len = btf_ext->hdr->func_info_len,
|
|
.min_rec_size = sizeof(struct bpf_func_info_min),
|
|
.ext_info = &btf_ext->func_info,
|
|
.desc = "func_info"
|
|
};
|
|
|
|
return btf_ext_setup_info(btf_ext, ¶m);
|
|
}
|
|
|
|
static int btf_ext_setup_line_info(struct btf_ext *btf_ext)
|
|
{
|
|
struct btf_ext_sec_setup_param param = {
|
|
.off = btf_ext->hdr->line_info_off,
|
|
.len = btf_ext->hdr->line_info_len,
|
|
.min_rec_size = sizeof(struct bpf_line_info_min),
|
|
.ext_info = &btf_ext->line_info,
|
|
.desc = "line_info",
|
|
};
|
|
|
|
return btf_ext_setup_info(btf_ext, ¶m);
|
|
}
|
|
|
|
static int btf_ext_parse_hdr(__u8 *data, __u32 data_size)
|
|
{
|
|
const struct btf_ext_header *hdr = (struct btf_ext_header *)data;
|
|
|
|
if (data_size < offsetof(struct btf_ext_header, func_info_off) ||
|
|
data_size < hdr->hdr_len) {
|
|
pr_debug("BTF.ext header not found");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (hdr->magic != BTF_MAGIC) {
|
|
pr_debug("Invalid BTF.ext magic:%x\n", hdr->magic);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (hdr->version != BTF_VERSION) {
|
|
pr_debug("Unsupported BTF.ext version:%u\n", hdr->version);
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
if (hdr->flags) {
|
|
pr_debug("Unsupported BTF.ext flags:%x\n", hdr->flags);
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
if (data_size == hdr->hdr_len) {
|
|
pr_debug("BTF.ext has no data\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
void btf_ext__free(struct btf_ext *btf_ext)
|
|
{
|
|
if (!btf_ext)
|
|
return;
|
|
free(btf_ext->data);
|
|
free(btf_ext);
|
|
}
|
|
|
|
struct btf_ext *btf_ext__new(__u8 *data, __u32 size)
|
|
{
|
|
struct btf_ext *btf_ext;
|
|
int err;
|
|
|
|
err = btf_ext_parse_hdr(data, size);
|
|
if (err)
|
|
return ERR_PTR(err);
|
|
|
|
btf_ext = calloc(1, sizeof(struct btf_ext));
|
|
if (!btf_ext)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
btf_ext->data_size = size;
|
|
btf_ext->data = malloc(size);
|
|
if (!btf_ext->data) {
|
|
err = -ENOMEM;
|
|
goto done;
|
|
}
|
|
memcpy(btf_ext->data, data, size);
|
|
|
|
err = btf_ext_setup_func_info(btf_ext);
|
|
if (err)
|
|
goto done;
|
|
|
|
err = btf_ext_setup_line_info(btf_ext);
|
|
if (err)
|
|
goto done;
|
|
|
|
done:
|
|
if (err) {
|
|
btf_ext__free(btf_ext);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
return btf_ext;
|
|
}
|
|
|
|
const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size)
|
|
{
|
|
*size = btf_ext->data_size;
|
|
return btf_ext->data;
|
|
}
|
|
|
|
static int btf_ext_reloc_info(const struct btf *btf,
|
|
const struct btf_ext_info *ext_info,
|
|
const char *sec_name, __u32 insns_cnt,
|
|
void **info, __u32 *cnt)
|
|
{
|
|
__u32 sec_hdrlen = sizeof(struct btf_ext_info_sec);
|
|
__u32 i, record_size, existing_len, records_len;
|
|
struct btf_ext_info_sec *sinfo;
|
|
const char *info_sec_name;
|
|
__u64 remain_len;
|
|
void *data;
|
|
|
|
record_size = ext_info->rec_size;
|
|
sinfo = ext_info->info;
|
|
remain_len = ext_info->len;
|
|
while (remain_len > 0) {
|
|
records_len = sinfo->num_info * record_size;
|
|
info_sec_name = btf__name_by_offset(btf, sinfo->sec_name_off);
|
|
if (strcmp(info_sec_name, sec_name)) {
|
|
remain_len -= sec_hdrlen + records_len;
|
|
sinfo = (void *)sinfo + sec_hdrlen + records_len;
|
|
continue;
|
|
}
|
|
|
|
existing_len = (*cnt) * record_size;
|
|
data = realloc(*info, existing_len + records_len);
|
|
if (!data)
|
|
return -ENOMEM;
|
|
|
|
memcpy(data + existing_len, sinfo->data, records_len);
|
|
/* adjust insn_off only, the rest data will be passed
|
|
* to the kernel.
|
|
*/
|
|
for (i = 0; i < sinfo->num_info; i++) {
|
|
__u32 *insn_off;
|
|
|
|
insn_off = data + existing_len + (i * record_size);
|
|
*insn_off = *insn_off / sizeof(struct bpf_insn) +
|
|
insns_cnt;
|
|
}
|
|
*info = data;
|
|
*cnt += sinfo->num_info;
|
|
return 0;
|
|
}
|
|
|
|
return -ENOENT;
|
|
}
|
|
|
|
int btf_ext__reloc_func_info(const struct btf *btf,
|
|
const struct btf_ext *btf_ext,
|
|
const char *sec_name, __u32 insns_cnt,
|
|
void **func_info, __u32 *cnt)
|
|
{
|
|
return btf_ext_reloc_info(btf, &btf_ext->func_info, sec_name,
|
|
insns_cnt, func_info, cnt);
|
|
}
|
|
|
|
int btf_ext__reloc_line_info(const struct btf *btf,
|
|
const struct btf_ext *btf_ext,
|
|
const char *sec_name, __u32 insns_cnt,
|
|
void **line_info, __u32 *cnt)
|
|
{
|
|
return btf_ext_reloc_info(btf, &btf_ext->line_info, sec_name,
|
|
insns_cnt, line_info, cnt);
|
|
}
|
|
|
|
__u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext)
|
|
{
|
|
return btf_ext->func_info.rec_size;
|
|
}
|
|
|
|
__u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext)
|
|
{
|
|
return btf_ext->line_info.rec_size;
|
|
}
|
|
|
|
struct btf_dedup;
|
|
|
|
static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext,
|
|
const struct btf_dedup_opts *opts);
|
|
static void btf_dedup_free(struct btf_dedup *d);
|
|
static int btf_dedup_strings(struct btf_dedup *d);
|
|
static int btf_dedup_prim_types(struct btf_dedup *d);
|
|
static int btf_dedup_struct_types(struct btf_dedup *d);
|
|
static int btf_dedup_ref_types(struct btf_dedup *d);
|
|
static int btf_dedup_compact_types(struct btf_dedup *d);
|
|
static int btf_dedup_remap_types(struct btf_dedup *d);
|
|
|
|
/*
|
|
* Deduplicate BTF types and strings.
|
|
*
|
|
* BTF dedup algorithm takes as an input `struct btf` representing `.BTF` ELF
|
|
* section with all BTF type descriptors and string data. It overwrites that
|
|
* memory in-place with deduplicated types and strings without any loss of
|
|
* information. If optional `struct btf_ext` representing '.BTF.ext' ELF section
|
|
* is provided, all the strings referenced from .BTF.ext section are honored
|
|
* and updated to point to the right offsets after deduplication.
|
|
*
|
|
* If function returns with error, type/string data might be garbled and should
|
|
* be discarded.
|
|
*
|
|
* More verbose and detailed description of both problem btf_dedup is solving,
|
|
* as well as solution could be found at:
|
|
* https://facebookmicrosites.github.io/bpf/blog/2018/11/14/btf-enhancement.html
|
|
*
|
|
* Problem description and justification
|
|
* =====================================
|
|
*
|
|
* BTF type information is typically emitted either as a result of conversion
|
|
* from DWARF to BTF or directly by compiler. In both cases, each compilation
|
|
* unit contains information about a subset of all the types that are used
|
|
* in an application. These subsets are frequently overlapping and contain a lot
|
|
* of duplicated information when later concatenated together into a single
|
|
* binary. This algorithm ensures that each unique type is represented by single
|
|
* BTF type descriptor, greatly reducing resulting size of BTF data.
|
|
*
|
|
* Compilation unit isolation and subsequent duplication of data is not the only
|
|
* problem. The same type hierarchy (e.g., struct and all the type that struct
|
|
* references) in different compilation units can be represented in BTF to
|
|
* various degrees of completeness (or, rather, incompleteness) due to
|
|
* struct/union forward declarations.
|
|
*
|
|
* Let's take a look at an example, that we'll use to better understand the
|
|
* problem (and solution). Suppose we have two compilation units, each using
|
|
* same `struct S`, but each of them having incomplete type information about
|
|
* struct's fields:
|
|
*
|
|
* // CU #1:
|
|
* struct S;
|
|
* struct A {
|
|
* int a;
|
|
* struct A* self;
|
|
* struct S* parent;
|
|
* };
|
|
* struct B;
|
|
* struct S {
|
|
* struct A* a_ptr;
|
|
* struct B* b_ptr;
|
|
* };
|
|
*
|
|
* // CU #2:
|
|
* struct S;
|
|
* struct A;
|
|
* struct B {
|
|
* int b;
|
|
* struct B* self;
|
|
* struct S* parent;
|
|
* };
|
|
* struct S {
|
|
* struct A* a_ptr;
|
|
* struct B* b_ptr;
|
|
* };
|
|
*
|
|
* In case of CU #1, BTF data will know only that `struct B` exist (but no
|
|
* more), but will know the complete type information about `struct A`. While
|
|
* for CU #2, it will know full type information about `struct B`, but will
|
|
* only know about forward declaration of `struct A` (in BTF terms, it will
|
|
* have `BTF_KIND_FWD` type descriptor with name `B`).
|
|
*
|
|
* This compilation unit isolation means that it's possible that there is no
|
|
* single CU with complete type information describing structs `S`, `A`, and
|
|
* `B`. Also, we might get tons of duplicated and redundant type information.
|
|
*
|
|
* Additional complication we need to keep in mind comes from the fact that
|
|
* types, in general, can form graphs containing cycles, not just DAGs.
|
|
*
|
|
* While algorithm does deduplication, it also merges and resolves type
|
|
* information (unless disabled throught `struct btf_opts`), whenever possible.
|
|
* E.g., in the example above with two compilation units having partial type
|
|
* information for structs `A` and `B`, the output of algorithm will emit
|
|
* a single copy of each BTF type that describes structs `A`, `B`, and `S`
|
|
* (as well as type information for `int` and pointers), as if they were defined
|
|
* in a single compilation unit as:
|
|
*
|
|
* struct A {
|
|
* int a;
|
|
* struct A* self;
|
|
* struct S* parent;
|
|
* };
|
|
* struct B {
|
|
* int b;
|
|
* struct B* self;
|
|
* struct S* parent;
|
|
* };
|
|
* struct S {
|
|
* struct A* a_ptr;
|
|
* struct B* b_ptr;
|
|
* };
|
|
*
|
|
* Algorithm summary
|
|
* =================
|
|
*
|
|
* Algorithm completes its work in 6 separate passes:
|
|
*
|
|
* 1. Strings deduplication.
|
|
* 2. Primitive types deduplication (int, enum, fwd).
|
|
* 3. Struct/union types deduplication.
|
|
* 4. Reference types deduplication (pointers, typedefs, arrays, funcs, func
|
|
* protos, and const/volatile/restrict modifiers).
|
|
* 5. Types compaction.
|
|
* 6. Types remapping.
|
|
*
|
|
* Algorithm determines canonical type descriptor, which is a single
|
|
* representative type for each truly unique type. This canonical type is the
|
|
* one that will go into final deduplicated BTF type information. For
|
|
* struct/unions, it is also the type that algorithm will merge additional type
|
|
* information into (while resolving FWDs), as it discovers it from data in
|
|
* other CUs. Each input BTF type eventually gets either mapped to itself, if
|
|
* that type is canonical, or to some other type, if that type is equivalent
|
|
* and was chosen as canonical representative. This mapping is stored in
|
|
* `btf_dedup->map` array. This map is also used to record STRUCT/UNION that
|
|
* FWD type got resolved to.
|
|
*
|
|
* To facilitate fast discovery of canonical types, we also maintain canonical
|
|
* index (`btf_dedup->dedup_table`), which maps type descriptor's signature hash
|
|
* (i.e., hashed kind, name, size, fields, etc) into a list of canonical types
|
|
* that match that signature. With sufficiently good choice of type signature
|
|
* hashing function, we can limit number of canonical types for each unique type
|
|
* signature to a very small number, allowing to find canonical type for any
|
|
* duplicated type very quickly.
|
|
*
|
|
* Struct/union deduplication is the most critical part and algorithm for
|
|
* deduplicating structs/unions is described in greater details in comments for
|
|
* `btf_dedup_is_equiv` function.
|
|
*/
|
|
int btf__dedup(struct btf *btf, struct btf_ext *btf_ext,
|
|
const struct btf_dedup_opts *opts)
|
|
{
|
|
struct btf_dedup *d = btf_dedup_new(btf, btf_ext, opts);
|
|
int err;
|
|
|
|
if (IS_ERR(d)) {
|
|
pr_debug("btf_dedup_new failed: %ld", PTR_ERR(d));
|
|
return -EINVAL;
|
|
}
|
|
|
|
err = btf_dedup_strings(d);
|
|
if (err < 0) {
|
|
pr_debug("btf_dedup_strings failed:%d\n", err);
|
|
goto done;
|
|
}
|
|
err = btf_dedup_prim_types(d);
|
|
if (err < 0) {
|
|
pr_debug("btf_dedup_prim_types failed:%d\n", err);
|
|
goto done;
|
|
}
|
|
err = btf_dedup_struct_types(d);
|
|
if (err < 0) {
|
|
pr_debug("btf_dedup_struct_types failed:%d\n", err);
|
|
goto done;
|
|
}
|
|
err = btf_dedup_ref_types(d);
|
|
if (err < 0) {
|
|
pr_debug("btf_dedup_ref_types failed:%d\n", err);
|
|
goto done;
|
|
}
|
|
err = btf_dedup_compact_types(d);
|
|
if (err < 0) {
|
|
pr_debug("btf_dedup_compact_types failed:%d\n", err);
|
|
goto done;
|
|
}
|
|
err = btf_dedup_remap_types(d);
|
|
if (err < 0) {
|
|
pr_debug("btf_dedup_remap_types failed:%d\n", err);
|
|
goto done;
|
|
}
|
|
|
|
done:
|
|
btf_dedup_free(d);
|
|
return err;
|
|
}
|
|
|
|
#define BTF_DEDUP_TABLE_DEFAULT_SIZE (1 << 14)
|
|
#define BTF_DEDUP_TABLE_MAX_SIZE_LOG 31
|
|
#define BTF_UNPROCESSED_ID ((__u32)-1)
|
|
#define BTF_IN_PROGRESS_ID ((__u32)-2)
|
|
|
|
struct btf_dedup_node {
|
|
struct btf_dedup_node *next;
|
|
__u32 type_id;
|
|
};
|
|
|
|
struct btf_dedup {
|
|
/* .BTF section to be deduped in-place */
|
|
struct btf *btf;
|
|
/*
|
|
* Optional .BTF.ext section. When provided, any strings referenced
|
|
* from it will be taken into account when deduping strings
|
|
*/
|
|
struct btf_ext *btf_ext;
|
|
/*
|
|
* This is a map from any type's signature hash to a list of possible
|
|
* canonical representative type candidates. Hash collisions are
|
|
* ignored, so even types of various kinds can share same list of
|
|
* candidates, which is fine because we rely on subsequent
|
|
* btf_xxx_equal() checks to authoritatively verify type equality.
|
|
*/
|
|
struct btf_dedup_node **dedup_table;
|
|
/* Canonical types map */
|
|
__u32 *map;
|
|
/* Hypothetical mapping, used during type graph equivalence checks */
|
|
__u32 *hypot_map;
|
|
__u32 *hypot_list;
|
|
size_t hypot_cnt;
|
|
size_t hypot_cap;
|
|
/* Various option modifying behavior of algorithm */
|
|
struct btf_dedup_opts opts;
|
|
};
|
|
|
|
struct btf_str_ptr {
|
|
const char *str;
|
|
__u32 new_off;
|
|
bool used;
|
|
};
|
|
|
|
struct btf_str_ptrs {
|
|
struct btf_str_ptr *ptrs;
|
|
const char *data;
|
|
__u32 cnt;
|
|
__u32 cap;
|
|
};
|
|
|
|
static inline __u32 hash_combine(__u32 h, __u32 value)
|
|
{
|
|
/* 2^31 + 2^29 - 2^25 + 2^22 - 2^19 - 2^16 + 1 */
|
|
#define GOLDEN_RATIO_PRIME 0x9e370001UL
|
|
return h * 37 + value * GOLDEN_RATIO_PRIME;
|
|
#undef GOLDEN_RATIO_PRIME
|
|
}
|
|
|
|
#define for_each_dedup_cand(d, hash, node) \
|
|
for (node = d->dedup_table[hash & (d->opts.dedup_table_size - 1)]; \
|
|
node; \
|
|
node = node->next)
|
|
|
|
static int btf_dedup_table_add(struct btf_dedup *d, __u32 hash, __u32 type_id)
|
|
{
|
|
struct btf_dedup_node *node = malloc(sizeof(struct btf_dedup_node));
|
|
int bucket = hash & (d->opts.dedup_table_size - 1);
|
|
|
|
if (!node)
|
|
return -ENOMEM;
|
|
node->type_id = type_id;
|
|
node->next = d->dedup_table[bucket];
|
|
d->dedup_table[bucket] = node;
|
|
return 0;
|
|
}
|
|
|
|
static int btf_dedup_hypot_map_add(struct btf_dedup *d,
|
|
__u32 from_id, __u32 to_id)
|
|
{
|
|
if (d->hypot_cnt == d->hypot_cap) {
|
|
__u32 *new_list;
|
|
|
|
d->hypot_cap += max(16, d->hypot_cap / 2);
|
|
new_list = realloc(d->hypot_list, sizeof(__u32) * d->hypot_cap);
|
|
if (!new_list)
|
|
return -ENOMEM;
|
|
d->hypot_list = new_list;
|
|
}
|
|
d->hypot_list[d->hypot_cnt++] = from_id;
|
|
d->hypot_map[from_id] = to_id;
|
|
return 0;
|
|
}
|
|
|
|
static void btf_dedup_clear_hypot_map(struct btf_dedup *d)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < d->hypot_cnt; i++)
|
|
d->hypot_map[d->hypot_list[i]] = BTF_UNPROCESSED_ID;
|
|
d->hypot_cnt = 0;
|
|
}
|
|
|
|
static void btf_dedup_table_free(struct btf_dedup *d)
|
|
{
|
|
struct btf_dedup_node *head, *tmp;
|
|
int i;
|
|
|
|
if (!d->dedup_table)
|
|
return;
|
|
|
|
for (i = 0; i < d->opts.dedup_table_size; i++) {
|
|
while (d->dedup_table[i]) {
|
|
tmp = d->dedup_table[i];
|
|
d->dedup_table[i] = tmp->next;
|
|
free(tmp);
|
|
}
|
|
|
|
head = d->dedup_table[i];
|
|
while (head) {
|
|
tmp = head;
|
|
head = head->next;
|
|
free(tmp);
|
|
}
|
|
}
|
|
|
|
free(d->dedup_table);
|
|
d->dedup_table = NULL;
|
|
}
|
|
|
|
static void btf_dedup_free(struct btf_dedup *d)
|
|
{
|
|
btf_dedup_table_free(d);
|
|
|
|
free(d->map);
|
|
d->map = NULL;
|
|
|
|
free(d->hypot_map);
|
|
d->hypot_map = NULL;
|
|
|
|
free(d->hypot_list);
|
|
d->hypot_list = NULL;
|
|
|
|
free(d);
|
|
}
|
|
|
|
/* Find closest power of two >= to size, capped at 2^max_size_log */
|
|
static __u32 roundup_pow2_max(__u32 size, int max_size_log)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < max_size_log && (1U << i) < size; i++)
|
|
;
|
|
return 1U << i;
|
|
}
|
|
|
|
|
|
static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext,
|
|
const struct btf_dedup_opts *opts)
|
|
{
|
|
struct btf_dedup *d = calloc(1, sizeof(struct btf_dedup));
|
|
int i, err = 0;
|
|
__u32 sz;
|
|
|
|
if (!d)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
d->opts.dont_resolve_fwds = opts && opts->dont_resolve_fwds;
|
|
sz = opts && opts->dedup_table_size ? opts->dedup_table_size
|
|
: BTF_DEDUP_TABLE_DEFAULT_SIZE;
|
|
sz = roundup_pow2_max(sz, BTF_DEDUP_TABLE_MAX_SIZE_LOG);
|
|
d->opts.dedup_table_size = sz;
|
|
|
|
d->btf = btf;
|
|
d->btf_ext = btf_ext;
|
|
|
|
d->dedup_table = calloc(d->opts.dedup_table_size,
|
|
sizeof(struct btf_dedup_node *));
|
|
if (!d->dedup_table) {
|
|
err = -ENOMEM;
|
|
goto done;
|
|
}
|
|
|
|
d->map = malloc(sizeof(__u32) * (1 + btf->nr_types));
|
|
if (!d->map) {
|
|
err = -ENOMEM;
|
|
goto done;
|
|
}
|
|
/* special BTF "void" type is made canonical immediately */
|
|
d->map[0] = 0;
|
|
for (i = 1; i <= btf->nr_types; i++) {
|
|
struct btf_type *t = d->btf->types[i];
|
|
__u16 kind = BTF_INFO_KIND(t->info);
|
|
|
|
/* VAR and DATASEC are never deduped and are self-canonical */
|
|
if (kind == BTF_KIND_VAR || kind == BTF_KIND_DATASEC)
|
|
d->map[i] = i;
|
|
else
|
|
d->map[i] = BTF_UNPROCESSED_ID;
|
|
}
|
|
|
|
d->hypot_map = malloc(sizeof(__u32) * (1 + btf->nr_types));
|
|
if (!d->hypot_map) {
|
|
err = -ENOMEM;
|
|
goto done;
|
|
}
|
|
for (i = 0; i <= btf->nr_types; i++)
|
|
d->hypot_map[i] = BTF_UNPROCESSED_ID;
|
|
|
|
done:
|
|
if (err) {
|
|
btf_dedup_free(d);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
return d;
|
|
}
|
|
|
|
typedef int (*str_off_fn_t)(__u32 *str_off_ptr, void *ctx);
|
|
|
|
/*
|
|
* Iterate over all possible places in .BTF and .BTF.ext that can reference
|
|
* string and pass pointer to it to a provided callback `fn`.
|
|
*/
|
|
static int btf_for_each_str_off(struct btf_dedup *d, str_off_fn_t fn, void *ctx)
|
|
{
|
|
void *line_data_cur, *line_data_end;
|
|
int i, j, r, rec_size;
|
|
struct btf_type *t;
|
|
|
|
for (i = 1; i <= d->btf->nr_types; i++) {
|
|
t = d->btf->types[i];
|
|
r = fn(&t->name_off, ctx);
|
|
if (r)
|
|
return r;
|
|
|
|
switch (BTF_INFO_KIND(t->info)) {
|
|
case BTF_KIND_STRUCT:
|
|
case BTF_KIND_UNION: {
|
|
struct btf_member *m = (struct btf_member *)(t + 1);
|
|
__u16 vlen = BTF_INFO_VLEN(t->info);
|
|
|
|
for (j = 0; j < vlen; j++) {
|
|
r = fn(&m->name_off, ctx);
|
|
if (r)
|
|
return r;
|
|
m++;
|
|
}
|
|
break;
|
|
}
|
|
case BTF_KIND_ENUM: {
|
|
struct btf_enum *m = (struct btf_enum *)(t + 1);
|
|
__u16 vlen = BTF_INFO_VLEN(t->info);
|
|
|
|
for (j = 0; j < vlen; j++) {
|
|
r = fn(&m->name_off, ctx);
|
|
if (r)
|
|
return r;
|
|
m++;
|
|
}
|
|
break;
|
|
}
|
|
case BTF_KIND_FUNC_PROTO: {
|
|
struct btf_param *m = (struct btf_param *)(t + 1);
|
|
__u16 vlen = BTF_INFO_VLEN(t->info);
|
|
|
|
for (j = 0; j < vlen; j++) {
|
|
r = fn(&m->name_off, ctx);
|
|
if (r)
|
|
return r;
|
|
m++;
|
|
}
|
|
break;
|
|
}
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!d->btf_ext)
|
|
return 0;
|
|
|
|
line_data_cur = d->btf_ext->line_info.info;
|
|
line_data_end = d->btf_ext->line_info.info + d->btf_ext->line_info.len;
|
|
rec_size = d->btf_ext->line_info.rec_size;
|
|
|
|
while (line_data_cur < line_data_end) {
|
|
struct btf_ext_info_sec *sec = line_data_cur;
|
|
struct bpf_line_info_min *line_info;
|
|
__u32 num_info = sec->num_info;
|
|
|
|
r = fn(&sec->sec_name_off, ctx);
|
|
if (r)
|
|
return r;
|
|
|
|
line_data_cur += sizeof(struct btf_ext_info_sec);
|
|
for (i = 0; i < num_info; i++) {
|
|
line_info = line_data_cur;
|
|
r = fn(&line_info->file_name_off, ctx);
|
|
if (r)
|
|
return r;
|
|
r = fn(&line_info->line_off, ctx);
|
|
if (r)
|
|
return r;
|
|
line_data_cur += rec_size;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int str_sort_by_content(const void *a1, const void *a2)
|
|
{
|
|
const struct btf_str_ptr *p1 = a1;
|
|
const struct btf_str_ptr *p2 = a2;
|
|
|
|
return strcmp(p1->str, p2->str);
|
|
}
|
|
|
|
static int str_sort_by_offset(const void *a1, const void *a2)
|
|
{
|
|
const struct btf_str_ptr *p1 = a1;
|
|
const struct btf_str_ptr *p2 = a2;
|
|
|
|
if (p1->str != p2->str)
|
|
return p1->str < p2->str ? -1 : 1;
|
|
return 0;
|
|
}
|
|
|
|
static int btf_dedup_str_ptr_cmp(const void *str_ptr, const void *pelem)
|
|
{
|
|
const struct btf_str_ptr *p = pelem;
|
|
|
|
if (str_ptr != p->str)
|
|
return (const char *)str_ptr < p->str ? -1 : 1;
|
|
return 0;
|
|
}
|
|
|
|
static int btf_str_mark_as_used(__u32 *str_off_ptr, void *ctx)
|
|
{
|
|
struct btf_str_ptrs *strs;
|
|
struct btf_str_ptr *s;
|
|
|
|
if (*str_off_ptr == 0)
|
|
return 0;
|
|
|
|
strs = ctx;
|
|
s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt,
|
|
sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp);
|
|
if (!s)
|
|
return -EINVAL;
|
|
s->used = true;
|
|
return 0;
|
|
}
|
|
|
|
static int btf_str_remap_offset(__u32 *str_off_ptr, void *ctx)
|
|
{
|
|
struct btf_str_ptrs *strs;
|
|
struct btf_str_ptr *s;
|
|
|
|
if (*str_off_ptr == 0)
|
|
return 0;
|
|
|
|
strs = ctx;
|
|
s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt,
|
|
sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp);
|
|
if (!s)
|
|
return -EINVAL;
|
|
*str_off_ptr = s->new_off;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Dedup string and filter out those that are not referenced from either .BTF
|
|
* or .BTF.ext (if provided) sections.
|
|
*
|
|
* This is done by building index of all strings in BTF's string section,
|
|
* then iterating over all entities that can reference strings (e.g., type
|
|
* names, struct field names, .BTF.ext line info, etc) and marking corresponding
|
|
* strings as used. After that all used strings are deduped and compacted into
|
|
* sequential blob of memory and new offsets are calculated. Then all the string
|
|
* references are iterated again and rewritten using new offsets.
|
|
*/
|
|
static int btf_dedup_strings(struct btf_dedup *d)
|
|
{
|
|
const struct btf_header *hdr = d->btf->hdr;
|
|
char *start = (char *)d->btf->nohdr_data + hdr->str_off;
|
|
char *end = start + d->btf->hdr->str_len;
|
|
char *p = start, *tmp_strs = NULL;
|
|
struct btf_str_ptrs strs = {
|
|
.cnt = 0,
|
|
.cap = 0,
|
|
.ptrs = NULL,
|
|
.data = start,
|
|
};
|
|
int i, j, err = 0, grp_idx;
|
|
bool grp_used;
|
|
|
|
/* build index of all strings */
|
|
while (p < end) {
|
|
if (strs.cnt + 1 > strs.cap) {
|
|
struct btf_str_ptr *new_ptrs;
|
|
|
|
strs.cap += max(strs.cnt / 2, 16);
|
|
new_ptrs = realloc(strs.ptrs,
|
|
sizeof(strs.ptrs[0]) * strs.cap);
|
|
if (!new_ptrs) {
|
|
err = -ENOMEM;
|
|
goto done;
|
|
}
|
|
strs.ptrs = new_ptrs;
|
|
}
|
|
|
|
strs.ptrs[strs.cnt].str = p;
|
|
strs.ptrs[strs.cnt].used = false;
|
|
|
|
p += strlen(p) + 1;
|
|
strs.cnt++;
|
|
}
|
|
|
|
/* temporary storage for deduplicated strings */
|
|
tmp_strs = malloc(d->btf->hdr->str_len);
|
|
if (!tmp_strs) {
|
|
err = -ENOMEM;
|
|
goto done;
|
|
}
|
|
|
|
/* mark all used strings */
|
|
strs.ptrs[0].used = true;
|
|
err = btf_for_each_str_off(d, btf_str_mark_as_used, &strs);
|
|
if (err)
|
|
goto done;
|
|
|
|
/* sort strings by context, so that we can identify duplicates */
|
|
qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_content);
|
|
|
|
/*
|
|
* iterate groups of equal strings and if any instance in a group was
|
|
* referenced, emit single instance and remember new offset
|
|
*/
|
|
p = tmp_strs;
|
|
grp_idx = 0;
|
|
grp_used = strs.ptrs[0].used;
|
|
/* iterate past end to avoid code duplication after loop */
|
|
for (i = 1; i <= strs.cnt; i++) {
|
|
/*
|
|
* when i == strs.cnt, we want to skip string comparison and go
|
|
* straight to handling last group of strings (otherwise we'd
|
|
* need to handle last group after the loop w/ duplicated code)
|
|
*/
|
|
if (i < strs.cnt &&
|
|
!strcmp(strs.ptrs[i].str, strs.ptrs[grp_idx].str)) {
|
|
grp_used = grp_used || strs.ptrs[i].used;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* this check would have been required after the loop to handle
|
|
* last group of strings, but due to <= condition in a loop
|
|
* we avoid that duplication
|
|
*/
|
|
if (grp_used) {
|
|
int new_off = p - tmp_strs;
|
|
__u32 len = strlen(strs.ptrs[grp_idx].str);
|
|
|
|
memmove(p, strs.ptrs[grp_idx].str, len + 1);
|
|
for (j = grp_idx; j < i; j++)
|
|
strs.ptrs[j].new_off = new_off;
|
|
p += len + 1;
|
|
}
|
|
|
|
if (i < strs.cnt) {
|
|
grp_idx = i;
|
|
grp_used = strs.ptrs[i].used;
|
|
}
|
|
}
|
|
|
|
/* replace original strings with deduped ones */
|
|
d->btf->hdr->str_len = p - tmp_strs;
|
|
memmove(start, tmp_strs, d->btf->hdr->str_len);
|
|
end = start + d->btf->hdr->str_len;
|
|
|
|
/* restore original order for further binary search lookups */
|
|
qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_offset);
|
|
|
|
/* remap string offsets */
|
|
err = btf_for_each_str_off(d, btf_str_remap_offset, &strs);
|
|
if (err)
|
|
goto done;
|
|
|
|
d->btf->hdr->str_len = end - start;
|
|
|
|
done:
|
|
free(tmp_strs);
|
|
free(strs.ptrs);
|
|
return err;
|
|
}
|
|
|
|
static __u32 btf_hash_common(struct btf_type *t)
|
|
{
|
|
__u32 h;
|
|
|
|
h = hash_combine(0, t->name_off);
|
|
h = hash_combine(h, t->info);
|
|
h = hash_combine(h, t->size);
|
|
return h;
|
|
}
|
|
|
|
static bool btf_equal_common(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
return t1->name_off == t2->name_off &&
|
|
t1->info == t2->info &&
|
|
t1->size == t2->size;
|
|
}
|
|
|
|
/* Calculate type signature hash of INT. */
|
|
static __u32 btf_hash_int(struct btf_type *t)
|
|
{
|
|
__u32 info = *(__u32 *)(t + 1);
|
|
__u32 h;
|
|
|
|
h = btf_hash_common(t);
|
|
h = hash_combine(h, info);
|
|
return h;
|
|
}
|
|
|
|
/* Check structural equality of two INTs. */
|
|
static bool btf_equal_int(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
__u32 info1, info2;
|
|
|
|
if (!btf_equal_common(t1, t2))
|
|
return false;
|
|
info1 = *(__u32 *)(t1 + 1);
|
|
info2 = *(__u32 *)(t2 + 1);
|
|
return info1 == info2;
|
|
}
|
|
|
|
/* Calculate type signature hash of ENUM. */
|
|
static __u32 btf_hash_enum(struct btf_type *t)
|
|
{
|
|
__u32 h;
|
|
|
|
/* don't hash vlen and enum members to support enum fwd resolving */
|
|
h = hash_combine(0, t->name_off);
|
|
h = hash_combine(h, t->info & ~0xffff);
|
|
h = hash_combine(h, t->size);
|
|
return h;
|
|
}
|
|
|
|
/* Check structural equality of two ENUMs. */
|
|
static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
struct btf_enum *m1, *m2;
|
|
__u16 vlen;
|
|
int i;
|
|
|
|
if (!btf_equal_common(t1, t2))
|
|
return false;
|
|
|
|
vlen = BTF_INFO_VLEN(t1->info);
|
|
m1 = (struct btf_enum *)(t1 + 1);
|
|
m2 = (struct btf_enum *)(t2 + 1);
|
|
for (i = 0; i < vlen; i++) {
|
|
if (m1->name_off != m2->name_off || m1->val != m2->val)
|
|
return false;
|
|
m1++;
|
|
m2++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static inline bool btf_is_enum_fwd(struct btf_type *t)
|
|
{
|
|
return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM &&
|
|
BTF_INFO_VLEN(t->info) == 0;
|
|
}
|
|
|
|
static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
if (!btf_is_enum_fwd(t1) && !btf_is_enum_fwd(t2))
|
|
return btf_equal_enum(t1, t2);
|
|
/* ignore vlen when comparing */
|
|
return t1->name_off == t2->name_off &&
|
|
(t1->info & ~0xffff) == (t2->info & ~0xffff) &&
|
|
t1->size == t2->size;
|
|
}
|
|
|
|
/*
|
|
* Calculate type signature hash of STRUCT/UNION, ignoring referenced type IDs,
|
|
* as referenced type IDs equivalence is established separately during type
|
|
* graph equivalence check algorithm.
|
|
*/
|
|
static __u32 btf_hash_struct(struct btf_type *t)
|
|
{
|
|
struct btf_member *member = (struct btf_member *)(t + 1);
|
|
__u32 vlen = BTF_INFO_VLEN(t->info);
|
|
__u32 h = btf_hash_common(t);
|
|
int i;
|
|
|
|
for (i = 0; i < vlen; i++) {
|
|
h = hash_combine(h, member->name_off);
|
|
h = hash_combine(h, member->offset);
|
|
/* no hashing of referenced type ID, it can be unresolved yet */
|
|
member++;
|
|
}
|
|
return h;
|
|
}
|
|
|
|
/*
|
|
* Check structural compatibility of two FUNC_PROTOs, ignoring referenced type
|
|
* IDs. This check is performed during type graph equivalence check and
|
|
* referenced types equivalence is checked separately.
|
|
*/
|
|
static bool btf_shallow_equal_struct(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
struct btf_member *m1, *m2;
|
|
__u16 vlen;
|
|
int i;
|
|
|
|
if (!btf_equal_common(t1, t2))
|
|
return false;
|
|
|
|
vlen = BTF_INFO_VLEN(t1->info);
|
|
m1 = (struct btf_member *)(t1 + 1);
|
|
m2 = (struct btf_member *)(t2 + 1);
|
|
for (i = 0; i < vlen; i++) {
|
|
if (m1->name_off != m2->name_off || m1->offset != m2->offset)
|
|
return false;
|
|
m1++;
|
|
m2++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Calculate type signature hash of ARRAY, including referenced type IDs,
|
|
* under assumption that they were already resolved to canonical type IDs and
|
|
* are not going to change.
|
|
*/
|
|
static __u32 btf_hash_array(struct btf_type *t)
|
|
{
|
|
struct btf_array *info = (struct btf_array *)(t + 1);
|
|
__u32 h = btf_hash_common(t);
|
|
|
|
h = hash_combine(h, info->type);
|
|
h = hash_combine(h, info->index_type);
|
|
h = hash_combine(h, info->nelems);
|
|
return h;
|
|
}
|
|
|
|
/*
|
|
* Check exact equality of two ARRAYs, taking into account referenced
|
|
* type IDs, under assumption that they were already resolved to canonical
|
|
* type IDs and are not going to change.
|
|
* This function is called during reference types deduplication to compare
|
|
* ARRAY to potential canonical representative.
|
|
*/
|
|
static bool btf_equal_array(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
struct btf_array *info1, *info2;
|
|
|
|
if (!btf_equal_common(t1, t2))
|
|
return false;
|
|
|
|
info1 = (struct btf_array *)(t1 + 1);
|
|
info2 = (struct btf_array *)(t2 + 1);
|
|
return info1->type == info2->type &&
|
|
info1->index_type == info2->index_type &&
|
|
info1->nelems == info2->nelems;
|
|
}
|
|
|
|
/*
|
|
* Check structural compatibility of two ARRAYs, ignoring referenced type
|
|
* IDs. This check is performed during type graph equivalence check and
|
|
* referenced types equivalence is checked separately.
|
|
*/
|
|
static bool btf_compat_array(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
struct btf_array *info1, *info2;
|
|
|
|
if (!btf_equal_common(t1, t2))
|
|
return false;
|
|
|
|
info1 = (struct btf_array *)(t1 + 1);
|
|
info2 = (struct btf_array *)(t2 + 1);
|
|
return info1->nelems == info2->nelems;
|
|
}
|
|
|
|
/*
|
|
* Calculate type signature hash of FUNC_PROTO, including referenced type IDs,
|
|
* under assumption that they were already resolved to canonical type IDs and
|
|
* are not going to change.
|
|
*/
|
|
static inline __u32 btf_hash_fnproto(struct btf_type *t)
|
|
{
|
|
struct btf_param *member = (struct btf_param *)(t + 1);
|
|
__u16 vlen = BTF_INFO_VLEN(t->info);
|
|
__u32 h = btf_hash_common(t);
|
|
int i;
|
|
|
|
for (i = 0; i < vlen; i++) {
|
|
h = hash_combine(h, member->name_off);
|
|
h = hash_combine(h, member->type);
|
|
member++;
|
|
}
|
|
return h;
|
|
}
|
|
|
|
/*
|
|
* Check exact equality of two FUNC_PROTOs, taking into account referenced
|
|
* type IDs, under assumption that they were already resolved to canonical
|
|
* type IDs and are not going to change.
|
|
* This function is called during reference types deduplication to compare
|
|
* FUNC_PROTO to potential canonical representative.
|
|
*/
|
|
static inline bool btf_equal_fnproto(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
struct btf_param *m1, *m2;
|
|
__u16 vlen;
|
|
int i;
|
|
|
|
if (!btf_equal_common(t1, t2))
|
|
return false;
|
|
|
|
vlen = BTF_INFO_VLEN(t1->info);
|
|
m1 = (struct btf_param *)(t1 + 1);
|
|
m2 = (struct btf_param *)(t2 + 1);
|
|
for (i = 0; i < vlen; i++) {
|
|
if (m1->name_off != m2->name_off || m1->type != m2->type)
|
|
return false;
|
|
m1++;
|
|
m2++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Check structural compatibility of two FUNC_PROTOs, ignoring referenced type
|
|
* IDs. This check is performed during type graph equivalence check and
|
|
* referenced types equivalence is checked separately.
|
|
*/
|
|
static inline bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2)
|
|
{
|
|
struct btf_param *m1, *m2;
|
|
__u16 vlen;
|
|
int i;
|
|
|
|
/* skip return type ID */
|
|
if (t1->name_off != t2->name_off || t1->info != t2->info)
|
|
return false;
|
|
|
|
vlen = BTF_INFO_VLEN(t1->info);
|
|
m1 = (struct btf_param *)(t1 + 1);
|
|
m2 = (struct btf_param *)(t2 + 1);
|
|
for (i = 0; i < vlen; i++) {
|
|
if (m1->name_off != m2->name_off)
|
|
return false;
|
|
m1++;
|
|
m2++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Deduplicate primitive types, that can't reference other types, by calculating
|
|
* their type signature hash and comparing them with any possible canonical
|
|
* candidate. If no canonical candidate matches, type itself is marked as
|
|
* canonical and is added into `btf_dedup->dedup_table` as another candidate.
|
|
*/
|
|
static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
|
|
{
|
|
struct btf_type *t = d->btf->types[type_id];
|
|
struct btf_type *cand;
|
|
struct btf_dedup_node *cand_node;
|
|
/* if we don't find equivalent type, then we are canonical */
|
|
__u32 new_id = type_id;
|
|
__u32 h;
|
|
|
|
switch (BTF_INFO_KIND(t->info)) {
|
|
case BTF_KIND_CONST:
|
|
case BTF_KIND_VOLATILE:
|
|
case BTF_KIND_RESTRICT:
|
|
case BTF_KIND_PTR:
|
|
case BTF_KIND_TYPEDEF:
|
|
case BTF_KIND_ARRAY:
|
|
case BTF_KIND_STRUCT:
|
|
case BTF_KIND_UNION:
|
|
case BTF_KIND_FUNC:
|
|
case BTF_KIND_FUNC_PROTO:
|
|
case BTF_KIND_VAR:
|
|
case BTF_KIND_DATASEC:
|
|
return 0;
|
|
|
|
case BTF_KIND_INT:
|
|
h = btf_hash_int(t);
|
|
for_each_dedup_cand(d, h, cand_node) {
|
|
cand = d->btf->types[cand_node->type_id];
|
|
if (btf_equal_int(t, cand)) {
|
|
new_id = cand_node->type_id;
|
|
break;
|
|
}
|
|
}
|
|
break;
|
|
|
|
case BTF_KIND_ENUM:
|
|
h = btf_hash_enum(t);
|
|
for_each_dedup_cand(d, h, cand_node) {
|
|
cand = d->btf->types[cand_node->type_id];
|
|
if (btf_equal_enum(t, cand)) {
|
|
new_id = cand_node->type_id;
|
|
break;
|
|
}
|
|
if (d->opts.dont_resolve_fwds)
|
|
continue;
|
|
if (btf_compat_enum(t, cand)) {
|
|
if (btf_is_enum_fwd(t)) {
|
|
/* resolve fwd to full enum */
|
|
new_id = cand_node->type_id;
|
|
break;
|
|
}
|
|
/* resolve canonical enum fwd to full enum */
|
|
d->map[cand_node->type_id] = type_id;
|
|
}
|
|
}
|
|
break;
|
|
|
|
case BTF_KIND_FWD:
|
|
h = btf_hash_common(t);
|
|
for_each_dedup_cand(d, h, cand_node) {
|
|
cand = d->btf->types[cand_node->type_id];
|
|
if (btf_equal_common(t, cand)) {
|
|
new_id = cand_node->type_id;
|
|
break;
|
|
}
|
|
}
|
|
break;
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
d->map[type_id] = new_id;
|
|
if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int btf_dedup_prim_types(struct btf_dedup *d)
|
|
{
|
|
int i, err;
|
|
|
|
for (i = 1; i <= d->btf->nr_types; i++) {
|
|
err = btf_dedup_prim_type(d, i);
|
|
if (err)
|
|
return err;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Check whether type is already mapped into canonical one (could be to itself).
|
|
*/
|
|
static inline bool is_type_mapped(struct btf_dedup *d, uint32_t type_id)
|
|
{
|
|
return d->map[type_id] <= BTF_MAX_NR_TYPES;
|
|
}
|
|
|
|
/*
|
|
* Resolve type ID into its canonical type ID, if any; otherwise return original
|
|
* type ID. If type is FWD and is resolved into STRUCT/UNION already, follow
|
|
* STRUCT/UNION link and resolve it into canonical type ID as well.
|
|
*/
|
|
static inline __u32 resolve_type_id(struct btf_dedup *d, __u32 type_id)
|
|
{
|
|
while (is_type_mapped(d, type_id) && d->map[type_id] != type_id)
|
|
type_id = d->map[type_id];
|
|
return type_id;
|
|
}
|
|
|
|
/*
|
|
* Resolve FWD to underlying STRUCT/UNION, if any; otherwise return original
|
|
* type ID.
|
|
*/
|
|
static uint32_t resolve_fwd_id(struct btf_dedup *d, uint32_t type_id)
|
|
{
|
|
__u32 orig_type_id = type_id;
|
|
|
|
if (BTF_INFO_KIND(d->btf->types[type_id]->info) != BTF_KIND_FWD)
|
|
return type_id;
|
|
|
|
while (is_type_mapped(d, type_id) && d->map[type_id] != type_id)
|
|
type_id = d->map[type_id];
|
|
|
|
if (BTF_INFO_KIND(d->btf->types[type_id]->info) != BTF_KIND_FWD)
|
|
return type_id;
|
|
|
|
return orig_type_id;
|
|
}
|
|
|
|
|
|
static inline __u16 btf_fwd_kind(struct btf_type *t)
|
|
{
|
|
return BTF_INFO_KFLAG(t->info) ? BTF_KIND_UNION : BTF_KIND_STRUCT;
|
|
}
|
|
|
|
/*
|
|
* Check equivalence of BTF type graph formed by candidate struct/union (we'll
|
|
* call it "candidate graph" in this description for brevity) to a type graph
|
|
* formed by (potential) canonical struct/union ("canonical graph" for brevity
|
|
* here, though keep in mind that not all types in canonical graph are
|
|
* necessarily canonical representatives themselves, some of them might be
|
|
* duplicates or its uniqueness might not have been established yet).
|
|
* Returns:
|
|
* - >0, if type graphs are equivalent;
|
|
* - 0, if not equivalent;
|
|
* - <0, on error.
|
|
*
|
|
* Algorithm performs side-by-side DFS traversal of both type graphs and checks
|
|
* equivalence of BTF types at each step. If at any point BTF types in candidate
|
|
* and canonical graphs are not compatible structurally, whole graphs are
|
|
* incompatible. If types are structurally equivalent (i.e., all information
|
|
* except referenced type IDs is exactly the same), a mapping from `canon_id` to
|
|
* a `cand_id` is recored in hypothetical mapping (`btf_dedup->hypot_map`).
|
|
* If a type references other types, then those referenced types are checked
|
|
* for equivalence recursively.
|
|
*
|
|
* During DFS traversal, if we find that for current `canon_id` type we
|
|
* already have some mapping in hypothetical map, we check for two possible
|
|
* situations:
|
|
* - `canon_id` is mapped to exactly the same type as `cand_id`. This will
|
|
* happen when type graphs have cycles. In this case we assume those two
|
|
* types are equivalent.
|
|
* - `canon_id` is mapped to different type. This is contradiction in our
|
|
* hypothetical mapping, because same graph in canonical graph corresponds
|
|
* to two different types in candidate graph, which for equivalent type
|
|
* graphs shouldn't happen. This condition terminates equivalence check
|
|
* with negative result.
|
|
*
|
|
* If type graphs traversal exhausts types to check and find no contradiction,
|
|
* then type graphs are equivalent.
|
|
*
|
|
* When checking types for equivalence, there is one special case: FWD types.
|
|
* If FWD type resolution is allowed and one of the types (either from canonical
|
|
* or candidate graph) is FWD and other is STRUCT/UNION (depending on FWD's kind
|
|
* flag) and their names match, hypothetical mapping is updated to point from
|
|
* FWD to STRUCT/UNION. If graphs will be determined as equivalent successfully,
|
|
* this mapping will be used to record FWD -> STRUCT/UNION mapping permanently.
|
|
*
|
|
* Technically, this could lead to incorrect FWD to STRUCT/UNION resolution,
|
|
* if there are two exactly named (or anonymous) structs/unions that are
|
|
* compatible structurally, one of which has FWD field, while other is concrete
|
|
* STRUCT/UNION, but according to C sources they are different structs/unions
|
|
* that are referencing different types with the same name. This is extremely
|
|
* unlikely to happen, but btf_dedup API allows to disable FWD resolution if
|
|
* this logic is causing problems.
|
|
*
|
|
* Doing FWD resolution means that both candidate and/or canonical graphs can
|
|
* consists of portions of the graph that come from multiple compilation units.
|
|
* This is due to the fact that types within single compilation unit are always
|
|
* deduplicated and FWDs are already resolved, if referenced struct/union
|
|
* definiton is available. So, if we had unresolved FWD and found corresponding
|
|
* STRUCT/UNION, they will be from different compilation units. This
|
|
* consequently means that when we "link" FWD to corresponding STRUCT/UNION,
|
|
* type graph will likely have at least two different BTF types that describe
|
|
* same type (e.g., most probably there will be two different BTF types for the
|
|
* same 'int' primitive type) and could even have "overlapping" parts of type
|
|
* graph that describe same subset of types.
|
|
*
|
|
* This in turn means that our assumption that each type in canonical graph
|
|
* must correspond to exactly one type in candidate graph might not hold
|
|
* anymore and will make it harder to detect contradictions using hypothetical
|
|
* map. To handle this problem, we allow to follow FWD -> STRUCT/UNION
|
|
* resolution only in canonical graph. FWDs in candidate graphs are never
|
|
* resolved. To see why it's OK, let's check all possible situations w.r.t. FWDs
|
|
* that can occur:
|
|
* - Both types in canonical and candidate graphs are FWDs. If they are
|
|
* structurally equivalent, then they can either be both resolved to the
|
|
* same STRUCT/UNION or not resolved at all. In both cases they are
|
|
* equivalent and there is no need to resolve FWD on candidate side.
|
|
* - Both types in canonical and candidate graphs are concrete STRUCT/UNION,
|
|
* so nothing to resolve as well, algorithm will check equivalence anyway.
|
|
* - Type in canonical graph is FWD, while type in candidate is concrete
|
|
* STRUCT/UNION. In this case candidate graph comes from single compilation
|
|
* unit, so there is exactly one BTF type for each unique C type. After
|
|
* resolving FWD into STRUCT/UNION, there might be more than one BTF type
|
|
* in canonical graph mapping to single BTF type in candidate graph, but
|
|
* because hypothetical mapping maps from canonical to candidate types, it's
|
|
* alright, and we still maintain the property of having single `canon_id`
|
|
* mapping to single `cand_id` (there could be two different `canon_id`
|
|
* mapped to the same `cand_id`, but it's not contradictory).
|
|
* - Type in canonical graph is concrete STRUCT/UNION, while type in candidate
|
|
* graph is FWD. In this case we are just going to check compatibility of
|
|
* STRUCT/UNION and corresponding FWD, and if they are compatible, we'll
|
|
* assume that whatever STRUCT/UNION FWD resolves to must be equivalent to
|
|
* a concrete STRUCT/UNION from canonical graph. If the rest of type graphs
|
|
* turn out equivalent, we'll re-resolve FWD to concrete STRUCT/UNION from
|
|
* canonical graph.
|
|
*/
|
|
static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id,
|
|
__u32 canon_id)
|
|
{
|
|
struct btf_type *cand_type;
|
|
struct btf_type *canon_type;
|
|
__u32 hypot_type_id;
|
|
__u16 cand_kind;
|
|
__u16 canon_kind;
|
|
int i, eq;
|
|
|
|
/* if both resolve to the same canonical, they must be equivalent */
|
|
if (resolve_type_id(d, cand_id) == resolve_type_id(d, canon_id))
|
|
return 1;
|
|
|
|
canon_id = resolve_fwd_id(d, canon_id);
|
|
|
|
hypot_type_id = d->hypot_map[canon_id];
|
|
if (hypot_type_id <= BTF_MAX_NR_TYPES)
|
|
return hypot_type_id == cand_id;
|
|
|
|
if (btf_dedup_hypot_map_add(d, canon_id, cand_id))
|
|
return -ENOMEM;
|
|
|
|
cand_type = d->btf->types[cand_id];
|
|
canon_type = d->btf->types[canon_id];
|
|
cand_kind = BTF_INFO_KIND(cand_type->info);
|
|
canon_kind = BTF_INFO_KIND(canon_type->info);
|
|
|
|
if (cand_type->name_off != canon_type->name_off)
|
|
return 0;
|
|
|
|
/* FWD <--> STRUCT/UNION equivalence check, if enabled */
|
|
if (!d->opts.dont_resolve_fwds
|
|
&& (cand_kind == BTF_KIND_FWD || canon_kind == BTF_KIND_FWD)
|
|
&& cand_kind != canon_kind) {
|
|
__u16 real_kind;
|
|
__u16 fwd_kind;
|
|
|
|
if (cand_kind == BTF_KIND_FWD) {
|
|
real_kind = canon_kind;
|
|
fwd_kind = btf_fwd_kind(cand_type);
|
|
} else {
|
|
real_kind = cand_kind;
|
|
fwd_kind = btf_fwd_kind(canon_type);
|
|
}
|
|
return fwd_kind == real_kind;
|
|
}
|
|
|
|
if (cand_kind != canon_kind)
|
|
return 0;
|
|
|
|
switch (cand_kind) {
|
|
case BTF_KIND_INT:
|
|
return btf_equal_int(cand_type, canon_type);
|
|
|
|
case BTF_KIND_ENUM:
|
|
if (d->opts.dont_resolve_fwds)
|
|
return btf_equal_enum(cand_type, canon_type);
|
|
else
|
|
return btf_compat_enum(cand_type, canon_type);
|
|
|
|
case BTF_KIND_FWD:
|
|
return btf_equal_common(cand_type, canon_type);
|
|
|
|
case BTF_KIND_CONST:
|
|
case BTF_KIND_VOLATILE:
|
|
case BTF_KIND_RESTRICT:
|
|
case BTF_KIND_PTR:
|
|
case BTF_KIND_TYPEDEF:
|
|
case BTF_KIND_FUNC:
|
|
if (cand_type->info != canon_type->info)
|
|
return 0;
|
|
return btf_dedup_is_equiv(d, cand_type->type, canon_type->type);
|
|
|
|
case BTF_KIND_ARRAY: {
|
|
struct btf_array *cand_arr, *canon_arr;
|
|
|
|
if (!btf_compat_array(cand_type, canon_type))
|
|
return 0;
|
|
cand_arr = (struct btf_array *)(cand_type + 1);
|
|
canon_arr = (struct btf_array *)(canon_type + 1);
|
|
eq = btf_dedup_is_equiv(d,
|
|
cand_arr->index_type, canon_arr->index_type);
|
|
if (eq <= 0)
|
|
return eq;
|
|
return btf_dedup_is_equiv(d, cand_arr->type, canon_arr->type);
|
|
}
|
|
|
|
case BTF_KIND_STRUCT:
|
|
case BTF_KIND_UNION: {
|
|
struct btf_member *cand_m, *canon_m;
|
|
__u16 vlen;
|
|
|
|
if (!btf_shallow_equal_struct(cand_type, canon_type))
|
|
return 0;
|
|
vlen = BTF_INFO_VLEN(cand_type->info);
|
|
cand_m = (struct btf_member *)(cand_type + 1);
|
|
canon_m = (struct btf_member *)(canon_type + 1);
|
|
for (i = 0; i < vlen; i++) {
|
|
eq = btf_dedup_is_equiv(d, cand_m->type, canon_m->type);
|
|
if (eq <= 0)
|
|
return eq;
|
|
cand_m++;
|
|
canon_m++;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
case BTF_KIND_FUNC_PROTO: {
|
|
struct btf_param *cand_p, *canon_p;
|
|
__u16 vlen;
|
|
|
|
if (!btf_compat_fnproto(cand_type, canon_type))
|
|
return 0;
|
|
eq = btf_dedup_is_equiv(d, cand_type->type, canon_type->type);
|
|
if (eq <= 0)
|
|
return eq;
|
|
vlen = BTF_INFO_VLEN(cand_type->info);
|
|
cand_p = (struct btf_param *)(cand_type + 1);
|
|
canon_p = (struct btf_param *)(canon_type + 1);
|
|
for (i = 0; i < vlen; i++) {
|
|
eq = btf_dedup_is_equiv(d, cand_p->type, canon_p->type);
|
|
if (eq <= 0)
|
|
return eq;
|
|
cand_p++;
|
|
canon_p++;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Use hypothetical mapping, produced by successful type graph equivalence
|
|
* check, to augment existing struct/union canonical mapping, where possible.
|
|
*
|
|
* If BTF_KIND_FWD resolution is allowed, this mapping is also used to record
|
|
* FWD -> STRUCT/UNION correspondence as well. FWD resolution is bidirectional:
|
|
* it doesn't matter if FWD type was part of canonical graph or candidate one,
|
|
* we are recording the mapping anyway. As opposed to carefulness required
|
|
* for struct/union correspondence mapping (described below), for FWD resolution
|
|
* it's not important, as by the time that FWD type (reference type) will be
|
|
* deduplicated all structs/unions will be deduped already anyway.
|
|
*
|
|
* Recording STRUCT/UNION mapping is purely a performance optimization and is
|
|
* not required for correctness. It needs to be done carefully to ensure that
|
|
* struct/union from candidate's type graph is not mapped into corresponding
|
|
* struct/union from canonical type graph that itself hasn't been resolved into
|
|
* canonical representative. The only guarantee we have is that canonical
|
|
* struct/union was determined as canonical and that won't change. But any
|
|
* types referenced through that struct/union fields could have been not yet
|
|
* resolved, so in case like that it's too early to establish any kind of
|
|
* correspondence between structs/unions.
|
|
*
|
|
* No canonical correspondence is derived for primitive types (they are already
|
|
* deduplicated completely already anyway) or reference types (they rely on
|
|
* stability of struct/union canonical relationship for equivalence checks).
|
|
*/
|
|
static void btf_dedup_merge_hypot_map(struct btf_dedup *d)
|
|
{
|
|
__u32 cand_type_id, targ_type_id;
|
|
__u16 t_kind, c_kind;
|
|
__u32 t_id, c_id;
|
|
int i;
|
|
|
|
for (i = 0; i < d->hypot_cnt; i++) {
|
|
cand_type_id = d->hypot_list[i];
|
|
targ_type_id = d->hypot_map[cand_type_id];
|
|
t_id = resolve_type_id(d, targ_type_id);
|
|
c_id = resolve_type_id(d, cand_type_id);
|
|
t_kind = BTF_INFO_KIND(d->btf->types[t_id]->info);
|
|
c_kind = BTF_INFO_KIND(d->btf->types[c_id]->info);
|
|
/*
|
|
* Resolve FWD into STRUCT/UNION.
|
|
* It's ok to resolve FWD into STRUCT/UNION that's not yet
|
|
* mapped to canonical representative (as opposed to
|
|
* STRUCT/UNION <--> STRUCT/UNION mapping logic below), because
|
|
* eventually that struct is going to be mapped and all resolved
|
|
* FWDs will automatically resolve to correct canonical
|
|
* representative. This will happen before ref type deduping,
|
|
* which critically depends on stability of these mapping. This
|
|
* stability is not a requirement for STRUCT/UNION equivalence
|
|
* checks, though.
|
|
*/
|
|
if (t_kind != BTF_KIND_FWD && c_kind == BTF_KIND_FWD)
|
|
d->map[c_id] = t_id;
|
|
else if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD)
|
|
d->map[t_id] = c_id;
|
|
|
|
if ((t_kind == BTF_KIND_STRUCT || t_kind == BTF_KIND_UNION) &&
|
|
c_kind != BTF_KIND_FWD &&
|
|
is_type_mapped(d, c_id) &&
|
|
!is_type_mapped(d, t_id)) {
|
|
/*
|
|
* as a perf optimization, we can map struct/union
|
|
* that's part of type graph we just verified for
|
|
* equivalence. We can do that for struct/union that has
|
|
* canonical representative only, though.
|
|
*/
|
|
d->map[t_id] = c_id;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Deduplicate struct/union types.
|
|
*
|
|
* For each struct/union type its type signature hash is calculated, taking
|
|
* into account type's name, size, number, order and names of fields, but
|
|
* ignoring type ID's referenced from fields, because they might not be deduped
|
|
* completely until after reference types deduplication phase. This type hash
|
|
* is used to iterate over all potential canonical types, sharing same hash.
|
|
* For each canonical candidate we check whether type graphs that they form
|
|
* (through referenced types in fields and so on) are equivalent using algorithm
|
|
* implemented in `btf_dedup_is_equiv`. If such equivalence is found and
|
|
* BTF_KIND_FWD resolution is allowed, then hypothetical mapping
|
|
* (btf_dedup->hypot_map) produced by aforementioned type graph equivalence
|
|
* algorithm is used to record FWD -> STRUCT/UNION mapping. It's also used to
|
|
* potentially map other structs/unions to their canonical representatives,
|
|
* if such relationship hasn't yet been established. This speeds up algorithm
|
|
* by eliminating some of the duplicate work.
|
|
*
|
|
* If no matching canonical representative was found, struct/union is marked
|
|
* as canonical for itself and is added into btf_dedup->dedup_table hash map
|
|
* for further look ups.
|
|
*/
|
|
static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id)
|
|
{
|
|
struct btf_dedup_node *cand_node;
|
|
struct btf_type *cand_type, *t;
|
|
/* if we don't find equivalent type, then we are canonical */
|
|
__u32 new_id = type_id;
|
|
__u16 kind;
|
|
__u32 h;
|
|
|
|
/* already deduped or is in process of deduping (loop detected) */
|
|
if (d->map[type_id] <= BTF_MAX_NR_TYPES)
|
|
return 0;
|
|
|
|
t = d->btf->types[type_id];
|
|
kind = BTF_INFO_KIND(t->info);
|
|
|
|
if (kind != BTF_KIND_STRUCT && kind != BTF_KIND_UNION)
|
|
return 0;
|
|
|
|
h = btf_hash_struct(t);
|
|
for_each_dedup_cand(d, h, cand_node) {
|
|
int eq;
|
|
|
|
/*
|
|
* Even though btf_dedup_is_equiv() checks for
|
|
* btf_shallow_equal_struct() internally when checking two
|
|
* structs (unions) for equivalence, we need to guard here
|
|
* from picking matching FWD type as a dedup candidate.
|
|
* This can happen due to hash collision. In such case just
|
|
* relying on btf_dedup_is_equiv() would lead to potentially
|
|
* creating a loop (FWD -> STRUCT and STRUCT -> FWD), because
|
|
* FWD and compatible STRUCT/UNION are considered equivalent.
|
|
*/
|
|
cand_type = d->btf->types[cand_node->type_id];
|
|
if (!btf_shallow_equal_struct(t, cand_type))
|
|
continue;
|
|
|
|
btf_dedup_clear_hypot_map(d);
|
|
eq = btf_dedup_is_equiv(d, type_id, cand_node->type_id);
|
|
if (eq < 0)
|
|
return eq;
|
|
if (!eq)
|
|
continue;
|
|
new_id = cand_node->type_id;
|
|
btf_dedup_merge_hypot_map(d);
|
|
break;
|
|
}
|
|
|
|
d->map[type_id] = new_id;
|
|
if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int btf_dedup_struct_types(struct btf_dedup *d)
|
|
{
|
|
int i, err;
|
|
|
|
for (i = 1; i <= d->btf->nr_types; i++) {
|
|
err = btf_dedup_struct_type(d, i);
|
|
if (err)
|
|
return err;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Deduplicate reference type.
|
|
*
|
|
* Once all primitive and struct/union types got deduplicated, we can easily
|
|
* deduplicate all other (reference) BTF types. This is done in two steps:
|
|
*
|
|
* 1. Resolve all referenced type IDs into their canonical type IDs. This
|
|
* resolution can be done either immediately for primitive or struct/union types
|
|
* (because they were deduped in previous two phases) or recursively for
|
|
* reference types. Recursion will always terminate at either primitive or
|
|
* struct/union type, at which point we can "unwind" chain of reference types
|
|
* one by one. There is no danger of encountering cycles because in C type
|
|
* system the only way to form type cycle is through struct/union, so any chain
|
|
* of reference types, even those taking part in a type cycle, will inevitably
|
|
* reach struct/union at some point.
|
|
*
|
|
* 2. Once all referenced type IDs are resolved into canonical ones, BTF type
|
|
* becomes "stable", in the sense that no further deduplication will cause
|
|
* any changes to it. With that, it's now possible to calculate type's signature
|
|
* hash (this time taking into account referenced type IDs) and loop over all
|
|
* potential canonical representatives. If no match was found, current type
|
|
* will become canonical representative of itself and will be added into
|
|
* btf_dedup->dedup_table as another possible canonical representative.
|
|
*/
|
|
static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
|
|
{
|
|
struct btf_dedup_node *cand_node;
|
|
struct btf_type *t, *cand;
|
|
/* if we don't find equivalent type, then we are representative type */
|
|
__u32 new_id = type_id;
|
|
int ref_type_id;
|
|
__u32 h;
|
|
|
|
if (d->map[type_id] == BTF_IN_PROGRESS_ID)
|
|
return -ELOOP;
|
|
if (d->map[type_id] <= BTF_MAX_NR_TYPES)
|
|
return resolve_type_id(d, type_id);
|
|
|
|
t = d->btf->types[type_id];
|
|
d->map[type_id] = BTF_IN_PROGRESS_ID;
|
|
|
|
switch (BTF_INFO_KIND(t->info)) {
|
|
case BTF_KIND_CONST:
|
|
case BTF_KIND_VOLATILE:
|
|
case BTF_KIND_RESTRICT:
|
|
case BTF_KIND_PTR:
|
|
case BTF_KIND_TYPEDEF:
|
|
case BTF_KIND_FUNC:
|
|
ref_type_id = btf_dedup_ref_type(d, t->type);
|
|
if (ref_type_id < 0)
|
|
return ref_type_id;
|
|
t->type = ref_type_id;
|
|
|
|
h = btf_hash_common(t);
|
|
for_each_dedup_cand(d, h, cand_node) {
|
|
cand = d->btf->types[cand_node->type_id];
|
|
if (btf_equal_common(t, cand)) {
|
|
new_id = cand_node->type_id;
|
|
break;
|
|
}
|
|
}
|
|
break;
|
|
|
|
case BTF_KIND_ARRAY: {
|
|
struct btf_array *info = (struct btf_array *)(t + 1);
|
|
|
|
ref_type_id = btf_dedup_ref_type(d, info->type);
|
|
if (ref_type_id < 0)
|
|
return ref_type_id;
|
|
info->type = ref_type_id;
|
|
|
|
ref_type_id = btf_dedup_ref_type(d, info->index_type);
|
|
if (ref_type_id < 0)
|
|
return ref_type_id;
|
|
info->index_type = ref_type_id;
|
|
|
|
h = btf_hash_array(t);
|
|
for_each_dedup_cand(d, h, cand_node) {
|
|
cand = d->btf->types[cand_node->type_id];
|
|
if (btf_equal_array(t, cand)) {
|
|
new_id = cand_node->type_id;
|
|
break;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
case BTF_KIND_FUNC_PROTO: {
|
|
struct btf_param *param;
|
|
__u16 vlen;
|
|
int i;
|
|
|
|
ref_type_id = btf_dedup_ref_type(d, t->type);
|
|
if (ref_type_id < 0)
|
|
return ref_type_id;
|
|
t->type = ref_type_id;
|
|
|
|
vlen = BTF_INFO_VLEN(t->info);
|
|
param = (struct btf_param *)(t + 1);
|
|
for (i = 0; i < vlen; i++) {
|
|
ref_type_id = btf_dedup_ref_type(d, param->type);
|
|
if (ref_type_id < 0)
|
|
return ref_type_id;
|
|
param->type = ref_type_id;
|
|
param++;
|
|
}
|
|
|
|
h = btf_hash_fnproto(t);
|
|
for_each_dedup_cand(d, h, cand_node) {
|
|
cand = d->btf->types[cand_node->type_id];
|
|
if (btf_equal_fnproto(t, cand)) {
|
|
new_id = cand_node->type_id;
|
|
break;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
d->map[type_id] = new_id;
|
|
if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
|
|
return -ENOMEM;
|
|
|
|
return new_id;
|
|
}
|
|
|
|
static int btf_dedup_ref_types(struct btf_dedup *d)
|
|
{
|
|
int i, err;
|
|
|
|
for (i = 1; i <= d->btf->nr_types; i++) {
|
|
err = btf_dedup_ref_type(d, i);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
btf_dedup_table_free(d);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Compact types.
|
|
*
|
|
* After we established for each type its corresponding canonical representative
|
|
* type, we now can eliminate types that are not canonical and leave only
|
|
* canonical ones layed out sequentially in memory by copying them over
|
|
* duplicates. During compaction btf_dedup->hypot_map array is reused to store
|
|
* a map from original type ID to a new compacted type ID, which will be used
|
|
* during next phase to "fix up" type IDs, referenced from struct/union and
|
|
* reference types.
|
|
*/
|
|
static int btf_dedup_compact_types(struct btf_dedup *d)
|
|
{
|
|
struct btf_type **new_types;
|
|
__u32 next_type_id = 1;
|
|
char *types_start, *p;
|
|
int i, len;
|
|
|
|
/* we are going to reuse hypot_map to store compaction remapping */
|
|
d->hypot_map[0] = 0;
|
|
for (i = 1; i <= d->btf->nr_types; i++)
|
|
d->hypot_map[i] = BTF_UNPROCESSED_ID;
|
|
|
|
types_start = d->btf->nohdr_data + d->btf->hdr->type_off;
|
|
p = types_start;
|
|
|
|
for (i = 1; i <= d->btf->nr_types; i++) {
|
|
if (d->map[i] != i)
|
|
continue;
|
|
|
|
len = btf_type_size(d->btf->types[i]);
|
|
if (len < 0)
|
|
return len;
|
|
|
|
memmove(p, d->btf->types[i], len);
|
|
d->hypot_map[i] = next_type_id;
|
|
d->btf->types[next_type_id] = (struct btf_type *)p;
|
|
p += len;
|
|
next_type_id++;
|
|
}
|
|
|
|
/* shrink struct btf's internal types index and update btf_header */
|
|
d->btf->nr_types = next_type_id - 1;
|
|
d->btf->types_size = d->btf->nr_types;
|
|
d->btf->hdr->type_len = p - types_start;
|
|
new_types = realloc(d->btf->types,
|
|
(1 + d->btf->nr_types) * sizeof(struct btf_type *));
|
|
if (!new_types)
|
|
return -ENOMEM;
|
|
d->btf->types = new_types;
|
|
|
|
/* make sure string section follows type information without gaps */
|
|
d->btf->hdr->str_off = p - (char *)d->btf->nohdr_data;
|
|
memmove(p, d->btf->strings, d->btf->hdr->str_len);
|
|
d->btf->strings = p;
|
|
p += d->btf->hdr->str_len;
|
|
|
|
d->btf->data_size = p - (char *)d->btf->data;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Figure out final (deduplicated and compacted) type ID for provided original
|
|
* `type_id` by first resolving it into corresponding canonical type ID and
|
|
* then mapping it to a deduplicated type ID, stored in btf_dedup->hypot_map,
|
|
* which is populated during compaction phase.
|
|
*/
|
|
static int btf_dedup_remap_type_id(struct btf_dedup *d, __u32 type_id)
|
|
{
|
|
__u32 resolved_type_id, new_type_id;
|
|
|
|
resolved_type_id = resolve_type_id(d, type_id);
|
|
new_type_id = d->hypot_map[resolved_type_id];
|
|
if (new_type_id > BTF_MAX_NR_TYPES)
|
|
return -EINVAL;
|
|
return new_type_id;
|
|
}
|
|
|
|
/*
|
|
* Remap referenced type IDs into deduped type IDs.
|
|
*
|
|
* After BTF types are deduplicated and compacted, their final type IDs may
|
|
* differ from original ones. The map from original to a corresponding
|
|
* deduped type ID is stored in btf_dedup->hypot_map and is populated during
|
|
* compaction phase. During remapping phase we are rewriting all type IDs
|
|
* referenced from any BTF type (e.g., struct fields, func proto args, etc) to
|
|
* their final deduped type IDs.
|
|
*/
|
|
static int btf_dedup_remap_type(struct btf_dedup *d, __u32 type_id)
|
|
{
|
|
struct btf_type *t = d->btf->types[type_id];
|
|
int i, r;
|
|
|
|
switch (BTF_INFO_KIND(t->info)) {
|
|
case BTF_KIND_INT:
|
|
case BTF_KIND_ENUM:
|
|
break;
|
|
|
|
case BTF_KIND_FWD:
|
|
case BTF_KIND_CONST:
|
|
case BTF_KIND_VOLATILE:
|
|
case BTF_KIND_RESTRICT:
|
|
case BTF_KIND_PTR:
|
|
case BTF_KIND_TYPEDEF:
|
|
case BTF_KIND_FUNC:
|
|
case BTF_KIND_VAR:
|
|
r = btf_dedup_remap_type_id(d, t->type);
|
|
if (r < 0)
|
|
return r;
|
|
t->type = r;
|
|
break;
|
|
|
|
case BTF_KIND_ARRAY: {
|
|
struct btf_array *arr_info = (struct btf_array *)(t + 1);
|
|
|
|
r = btf_dedup_remap_type_id(d, arr_info->type);
|
|
if (r < 0)
|
|
return r;
|
|
arr_info->type = r;
|
|
r = btf_dedup_remap_type_id(d, arr_info->index_type);
|
|
if (r < 0)
|
|
return r;
|
|
arr_info->index_type = r;
|
|
break;
|
|
}
|
|
|
|
case BTF_KIND_STRUCT:
|
|
case BTF_KIND_UNION: {
|
|
struct btf_member *member = (struct btf_member *)(t + 1);
|
|
__u16 vlen = BTF_INFO_VLEN(t->info);
|
|
|
|
for (i = 0; i < vlen; i++) {
|
|
r = btf_dedup_remap_type_id(d, member->type);
|
|
if (r < 0)
|
|
return r;
|
|
member->type = r;
|
|
member++;
|
|
}
|
|
break;
|
|
}
|
|
|
|
case BTF_KIND_FUNC_PROTO: {
|
|
struct btf_param *param = (struct btf_param *)(t + 1);
|
|
__u16 vlen = BTF_INFO_VLEN(t->info);
|
|
|
|
r = btf_dedup_remap_type_id(d, t->type);
|
|
if (r < 0)
|
|
return r;
|
|
t->type = r;
|
|
|
|
for (i = 0; i < vlen; i++) {
|
|
r = btf_dedup_remap_type_id(d, param->type);
|
|
if (r < 0)
|
|
return r;
|
|
param->type = r;
|
|
param++;
|
|
}
|
|
break;
|
|
}
|
|
|
|
case BTF_KIND_DATASEC: {
|
|
struct btf_var_secinfo *var = (struct btf_var_secinfo *)(t + 1);
|
|
__u16 vlen = BTF_INFO_VLEN(t->info);
|
|
|
|
for (i = 0; i < vlen; i++) {
|
|
r = btf_dedup_remap_type_id(d, var->type);
|
|
if (r < 0)
|
|
return r;
|
|
var->type = r;
|
|
var++;
|
|
}
|
|
break;
|
|
}
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int btf_dedup_remap_types(struct btf_dedup *d)
|
|
{
|
|
int i, r;
|
|
|
|
for (i = 1; i <= d->btf->nr_types; i++) {
|
|
r = btf_dedup_remap_type(d, i);
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
return 0;
|
|
}
|