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// Copyright 2017 The Crashpad Authors
//
// 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.
#include "snapshot/elf/elf_symbol_table_reader.h"
#include <elf.h>
#include "snapshot/elf/elf_image_reader.h"
namespace crashpad {
namespace {
uint8_t GetBinding(const Elf32_Sym& sym) {
return ELF32_ST_BIND(sym.st_info);
}
uint8_t GetBinding(const Elf64_Sym& sym) {
return ELF64_ST_BIND(sym.st_info);
}
uint8_t GetType(const Elf32_Sym& sym) {
return ELF32_ST_TYPE(sym.st_info);
}
uint8_t GetType(const Elf64_Sym& sym) {
return ELF64_ST_TYPE(sym.st_info);
}
uint8_t GetVisibility(const Elf32_Sym& sym) {
return ELF32_ST_VISIBILITY(sym.st_other);
}
uint8_t GetVisibility(const Elf64_Sym& sym) {
return ELF64_ST_VISIBILITY(sym.st_other);
}
} // namespace
ElfSymbolTableReader::ElfSymbolTableReader(const ProcessMemoryRange* memory,
ElfImageReader* elf_reader,
VMAddress address,
VMSize num_entries)
: memory_(memory),
elf_reader_(elf_reader),
base_address_(address),
num_entries_(num_entries) {}
ElfSymbolTableReader::~ElfSymbolTableReader() {}
bool ElfSymbolTableReader::GetSymbol(const std::string& name,
SymbolInformation* info) {
return memory_->Is64Bit() ? ScanSymbolTable<Elf64_Sym>(name, info)
: ScanSymbolTable<Elf32_Sym>(name, info);
}
template <typename SymEnt>
bool ElfSymbolTableReader::ScanSymbolTable(const std::string& name,
SymbolInformation* info_out) {
VMAddress address = base_address_;
SymEnt entry;
std::string string;
size_t i = 0;
while (i < num_entries_ && memory_->Read(address, sizeof(entry), &entry)) {
if (elf_reader_->ReadDynamicStringTableAtOffset(entry.st_name, &string) &&
string == name) {
info_out->address = entry.st_value;
info_out->size = entry.st_size;
info_out->shndx = entry.st_shndx;
info_out->binding = GetBinding(entry);
info_out->type = GetType(entry);
info_out->visibility = GetVisibility(entry);
return true;
}
// TODO(scottmg): This should respect DT_SYMENT if present.
address += sizeof(entry);
++i;
}
return false;
}
} // namespace crashpad