platform_system_core/libunwindstack/tests/ElfTestUtils.cpp
Christopher Ferris c3d79f7c07 Fix incorrect usage of relative pcs.
When stepping, it's necessary to use both the unaltered relative pc
and the adjusted relative pc. If the adjusted pc is not used, the
wrong unwind information can be used.

Added new offline unit tests that take real data and verifies that it
unwinds properly.

Fix a bug in the map code that would not properly parse map data for
a 64 bit process when done in a 32 bit process.

Fix bug in eh_frame processing that didn't adjust the pc correctly.
Fix unit tests related to the pc adjustment.

Bug: 69475565

Test: Passes libbacktrace/libunwindstack unit tests.
Test: Run debuggerd -b on processes on a hikey.
Change-Id: Ic501a1c4549c5f61d2742a7105c42a960f2c892b
2017-11-29 16:10:08 -08:00

142 lines
4.4 KiB
C++

/*
* Copyright (C) 2016 The Android Open Source Project
*
* 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 <elf.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <unistd.h>
#include <string>
#include <vector>
#include <gtest/gtest.h>
#include "ElfTestUtils.h"
namespace unwindstack {
template <typename Ehdr>
void TestInitEhdr(Ehdr* ehdr, uint32_t elf_class, uint32_t machine_type) {
memset(ehdr, 0, sizeof(Ehdr));
memcpy(&ehdr->e_ident[0], ELFMAG, SELFMAG);
ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
ehdr->e_ident[EI_VERSION] = EV_CURRENT;
ehdr->e_ident[EI_OSABI] = ELFOSABI_SYSV;
ehdr->e_ident[EI_CLASS] = elf_class;
ehdr->e_type = ET_DYN;
ehdr->e_machine = machine_type;
ehdr->e_version = EV_CURRENT;
ehdr->e_ehsize = sizeof(Ehdr);
}
std::string TestGetFileDirectory() {
std::string exec(testing::internal::GetArgvs()[0]);
auto const value = exec.find_last_of('/');
if (value == std::string::npos) {
return "tests/files/";
}
return exec.substr(0, value + 1) + "tests/files/";
}
template <typename Ehdr, typename Shdr>
void TestInitGnuDebugdata(uint32_t elf_class, uint32_t machine, bool init_gnu_debugdata,
TestCopyFuncType copy_func) {
Ehdr ehdr;
TestInitEhdr(&ehdr, elf_class, machine);
uint64_t offset = sizeof(Ehdr);
ehdr.e_shoff = offset;
ehdr.e_shnum = 3;
ehdr.e_shentsize = sizeof(Shdr);
ehdr.e_shstrndx = 2;
copy_func(0, &ehdr, sizeof(ehdr));
Shdr shdr;
memset(&shdr, 0, sizeof(shdr));
shdr.sh_type = SHT_NULL;
copy_func(offset, &shdr, sizeof(shdr));
offset += ehdr.e_shentsize;
// Skip this header, it will contain the gnu_debugdata information.
uint64_t gnu_offset = offset;
offset += ehdr.e_shentsize;
uint64_t symtab_offset = sizeof(ehdr) + ehdr.e_shnum * ehdr.e_shentsize;
memset(&shdr, 0, sizeof(shdr));
shdr.sh_name = 1;
shdr.sh_type = SHT_STRTAB;
shdr.sh_offset = symtab_offset;
shdr.sh_size = 0x100;
copy_func(offset, &shdr, sizeof(shdr));
char value = '\0';
uint64_t symname_offset = symtab_offset;
copy_func(symname_offset, &value, 1);
symname_offset++;
std::string name(".shstrtab");
copy_func(symname_offset, name.c_str(), name.size() + 1);
symname_offset += name.size() + 1;
name = ".gnu_debugdata";
copy_func(symname_offset, name.c_str(), name.size() + 1);
ssize_t bytes = 0x100;
offset = symtab_offset + 0x100;
if (init_gnu_debugdata) {
// Read in the compressed elf data and copy it in.
name = TestGetFileDirectory();
if (elf_class == ELFCLASS32) {
name += "elf32.xz";
} else {
name += "elf64.xz";
}
int fd = TEMP_FAILURE_RETRY(open(name.c_str(), O_RDONLY));
ASSERT_NE(-1, fd) << "Cannot open " + name;
// Assumes the file is less than 1024 bytes.
std::vector<uint8_t> buf(1024);
bytes = TEMP_FAILURE_RETRY(read(fd, buf.data(), buf.size()));
ASSERT_GT(bytes, 0);
// Make sure the file isn't too big.
ASSERT_NE(static_cast<size_t>(bytes), buf.size())
<< "File " + name + " is too big, increase buffer size.";
close(fd);
buf.resize(bytes);
copy_func(offset, buf.data(), buf.size());
}
memset(&shdr, 0, sizeof(shdr));
shdr.sh_type = SHT_PROGBITS;
shdr.sh_name = symname_offset - symtab_offset;
shdr.sh_addr = offset;
shdr.sh_offset = offset;
shdr.sh_size = bytes;
copy_func(gnu_offset, &shdr, sizeof(shdr));
}
template void TestInitEhdr<Elf32_Ehdr>(Elf32_Ehdr*, uint32_t, uint32_t);
template void TestInitEhdr<Elf64_Ehdr>(Elf64_Ehdr*, uint32_t, uint32_t);
template void TestInitGnuDebugdata<Elf32_Ehdr, Elf32_Shdr>(uint32_t, uint32_t, bool,
TestCopyFuncType);
template void TestInitGnuDebugdata<Elf64_Ehdr, Elf64_Shdr>(uint32_t, uint32_t, bool,
TestCopyFuncType);
} // namespace unwindstack