2 * Copyright 2012-present Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #ifndef FOLLY_EXPERIMENTAL_SYMBOLIZER_ELF_H_
18 #error This file must be included from Elf.h
22 namespace symbolizer {
25 const ElfPhdr* ElfFile::iterateProgramHeaders(Fn fn) const {
26 // there exist ELF binaries which execute correctly, but have invalid internal
27 // offset(s) to program/section headers; most probably due to invalid
28 // stripping of symbols
29 if (elfHeader().e_phoff + sizeof(ElfPhdr) >= length_) {
33 const ElfPhdr* ptr = &at<ElfPhdr>(elfHeader().e_phoff);
34 for (size_t i = 0; i < elfHeader().e_phnum; i++, ptr++) {
43 const ElfShdr* ElfFile::iterateSections(Fn fn) const {
44 // there exist ELF binaries which execute correctly, but have invalid internal
45 // offset(s) to program/section headers; most probably due to invalid
46 // stripping of symbols
47 if (elfHeader().e_shoff + sizeof(ElfShdr) >= length_) {
51 const ElfShdr* ptr = &at<ElfShdr>(elfHeader().e_shoff);
52 for (size_t i = 0; i < elfHeader().e_shnum; i++, ptr++) {
61 const ElfShdr* ElfFile::iterateSectionsWithType(uint32_t type, Fn fn) const {
62 return iterateSections(
63 [&](const ElfShdr& sh) { return sh.sh_type == type && fn(sh); });
67 const ElfShdr* ElfFile::iterateSectionsWithTypes(
68 std::initializer_list<uint32_t> types,
70 return iterateSections([&](const ElfShdr& sh) {
71 auto const it = std::find(types.begin(), types.end(), sh.sh_type);
72 return it != types.end() && fn(sh);
77 const char* ElfFile::iterateStrings(const ElfShdr& stringTable, Fn fn) const {
78 validateStringTable(stringTable);
80 const char* start = file_ + stringTable.sh_offset;
81 const char* end = start + stringTable.sh_size;
83 const char* ptr = start;
84 while (ptr != end && !fn(ptr)) {
85 ptr += strlen(ptr) + 1;
88 return ptr != end ? ptr : nullptr;
92 const ElfSym* ElfFile::iterateSymbols(const ElfShdr& section, Fn fn) const {
94 section.sh_entsize == sizeof(ElfSym),
95 "invalid entry size in symbol table");
97 const ElfSym* sym = &at<ElfSym>(section.sh_offset);
98 const ElfSym* end = sym + (section.sh_size / section.sh_entsize);
112 const ElfSym* ElfFile::iterateSymbolsWithType(
113 const ElfShdr& section,
116 // N.B. st_info has the same representation on 32- and 64-bit platforms
117 return iterateSymbols(section, [&](const ElfSym& sym) -> bool {
118 return ELF32_ST_TYPE(sym.st_info) == type && fn(sym);
123 const ElfSym* ElfFile::iterateSymbolsWithTypes(
124 const ElfShdr& section,
125 std::initializer_list<uint32_t> types,
127 // N.B. st_info has the same representation on 32- and 64-bit platforms
128 return iterateSymbols(section, [&](const ElfSym& sym) -> bool {
129 auto const elfType = ELF32_ST_TYPE(sym.st_info);
130 auto const it = std::find(types.begin(), types.end(), elfType);
131 return it != types.end() && fn(sym);
135 } // namespace symbolizer