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- /*
- * Copyright 2012-present Facebook, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- #ifndef FOLLY_EXPERIMENTAL_SYMBOLIZER_ELF_H_
- #error This file must be included from Elf.h
- #endif
- namespace folly {
- namespace symbolizer {
- template <class Fn>
- const ElfPhdr* ElfFile::iterateProgramHeaders(Fn fn) const {
- // there exist ELF binaries which execute correctly, but have invalid internal
- // offset(s) to program/section headers; most probably due to invalid
- // stripping of symbols
- if (elfHeader().e_phoff + sizeof(ElfPhdr) >= length_) {
- return nullptr;
- }
- const ElfPhdr* ptr = &at<ElfPhdr>(elfHeader().e_phoff);
- for (size_t i = 0; i < elfHeader().e_phnum; i++, ptr++) {
- if (fn(*ptr)) {
- return ptr;
- }
- }
- return nullptr;
- }
- template <class Fn>
- const ElfShdr* ElfFile::iterateSections(Fn fn) const {
- // there exist ELF binaries which execute correctly, but have invalid internal
- // offset(s) to program/section headers; most probably due to invalid
- // stripping of symbols
- if (elfHeader().e_shoff + sizeof(ElfShdr) >= length_) {
- return nullptr;
- }
- const ElfShdr* ptr = &at<ElfShdr>(elfHeader().e_shoff);
- for (size_t i = 0; i < elfHeader().e_shnum; i++, ptr++) {
- if (fn(*ptr)) {
- return ptr;
- }
- }
- return nullptr;
- }
- template <class Fn>
- const ElfShdr* ElfFile::iterateSectionsWithType(uint32_t type, Fn fn) const {
- return iterateSections(
- [&](const ElfShdr& sh) { return sh.sh_type == type && fn(sh); });
- }
- template <class Fn>
- const ElfShdr* ElfFile::iterateSectionsWithTypes(
- std::initializer_list<uint32_t> types,
- Fn fn) const {
- return iterateSections([&](const ElfShdr& sh) {
- auto const it = std::find(types.begin(), types.end(), sh.sh_type);
- return it != types.end() && fn(sh);
- });
- }
- template <class Fn>
- const char* ElfFile::iterateStrings(const ElfShdr& stringTable, Fn fn) const {
- validateStringTable(stringTable);
- const char* start = file_ + stringTable.sh_offset;
- const char* end = start + stringTable.sh_size;
- const char* ptr = start;
- while (ptr != end && !fn(ptr)) {
- ptr += strlen(ptr) + 1;
- }
- return ptr != end ? ptr : nullptr;
- }
- template <class Fn>
- const ElfSym* ElfFile::iterateSymbols(const ElfShdr& section, Fn fn) const {
- FOLLY_SAFE_CHECK(
- section.sh_entsize == sizeof(ElfSym),
- "invalid entry size in symbol table");
- const ElfSym* sym = &at<ElfSym>(section.sh_offset);
- const ElfSym* end = sym + (section.sh_size / section.sh_entsize);
- while (sym < end) {
- if (fn(*sym)) {
- return sym;
- }
- ++sym;
- }
- return nullptr;
- }
- template <class Fn>
- const ElfSym* ElfFile::iterateSymbolsWithType(
- const ElfShdr& section,
- uint32_t type,
- Fn fn) const {
- // N.B. st_info has the same representation on 32- and 64-bit platforms
- return iterateSymbols(section, [&](const ElfSym& sym) -> bool {
- return ELF32_ST_TYPE(sym.st_info) == type && fn(sym);
- });
- }
- template <class Fn>
- const ElfSym* ElfFile::iterateSymbolsWithTypes(
- const ElfShdr& section,
- std::initializer_list<uint32_t> types,
- Fn fn) const {
- // N.B. st_info has the same representation on 32- and 64-bit platforms
- return iterateSymbols(section, [&](const ElfSym& sym) -> bool {
- auto const elfType = ELF32_ST_TYPE(sym.st_info);
- auto const it = std::find(types.begin(), types.end(), elfType);
- return it != types.end() && fn(sym);
- });
- }
- } // namespace symbolizer
- } // namespace folly
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