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platform_system_core/libunwindstack/tests/SymbolsTest.cpp
Christopher Ferris 4cc36d2b43 Fix handling of load bias values. 
It turns out that for the dwarf information, if a FDE indicates it's pc
relative, then pc has to be incremented by the load bias. If not, then
it should not be incremented.

Previously, the code always subtracted load bias values from pcs, and assumed
that all fdes were incremented by load bias values. The new code actually
reads the fdes and adjusted the pcs in the fde and in the eh frame hdr so
that load bias values are already handled properly.

In addition, add dumping of arm exidx values in unwind_reg_info. This allowed
verifying that the debug frame in those elf files was being handled properly.

Added a new unit test that only has a debug frame that has a non-zero load
bias and has fde entries that do not have pc relative encoding.

Fix a couple of other small bugs.

Bug: 109824792

Test: All libbacktrace/libunwindstack unit tests pass.
Test: Ran ART 137-cfi test and 004-ThreadStress.
Test: Verify that displaying the fde start and end pc actually match the
Test: real data for fde that have pc relative set, and that don't.
Test: Verified that the unwind information for arm exidx matches the
Test: debug frame data.

Change-Id: I707555286b5cb05df9f25489e8c5ede753cfe0fb
2018-06-11 18:53:55 -07:00

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/*
* 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 <signal.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
#include <vector>
#include <android-base/file.h>
#include <android-base/test_utils.h>
#include <gtest/gtest.h>
#include <unwindstack/Memory.h>
#include "MemoryFake.h"
#include "Symbols.h"
namespace unwindstack {
template <typename TypeParam>
class SymbolsTest : public ::testing::Test {
protected:
void SetUp() override { memory_.Clear(); }
void InitSym(TypeParam* sym, uint32_t st_value, uint32_t st_size, uint32_t st_name) {
memset(sym, 0, sizeof(*sym));
sym->st_info = STT_FUNC;
sym->st_value = st_value;
sym->st_size = st_size;
sym->st_name = st_name;
sym->st_shndx = SHN_COMMON;
}
MemoryFake memory_;
};
TYPED_TEST_CASE_P(SymbolsTest);
TYPED_TEST_P(SymbolsTest, function_bounds_check) {
Symbols symbols(0x1000, sizeof(TypeParam), sizeof(TypeParam), 0x2000, 0x100);
TypeParam sym;
this->InitSym(&sym, 0x5000, 0x10, 0x40);
uint64_t offset = 0x1000;
this->memory_.SetMemory(offset, &sym, sizeof(sym));
std::string fake_name("fake_function");
this->memory_.SetMemory(0x2040, fake_name.c_str(), fake_name.size() + 1);
std::string name;
uint64_t func_offset;
ASSERT_TRUE(symbols.GetName<TypeParam>(0x5000, &this->memory_, &name, &func_offset));
ASSERT_EQ("fake_function", name);
ASSERT_EQ(0U, func_offset);
name.clear();
ASSERT_TRUE(symbols.GetName<TypeParam>(0x500f, &this->memory_, &name, &func_offset));
ASSERT_EQ("fake_function", name);
ASSERT_EQ(0xfU, func_offset);
// Check one before and one after the function.
ASSERT_FALSE(symbols.GetName<TypeParam>(0x4fff, &this->memory_, &name, &func_offset));
ASSERT_FALSE(symbols.GetName<TypeParam>(0x5010, &this->memory_, &name, &func_offset));
}
TYPED_TEST_P(SymbolsTest, no_symbol) {
Symbols symbols(0x1000, sizeof(TypeParam), sizeof(TypeParam), 0x2000, 0x100);
TypeParam sym;
this->InitSym(&sym, 0x5000, 0x10, 0x40);
uint64_t offset = 0x1000;
this->memory_.SetMemory(offset, &sym, sizeof(sym));
std::string fake_name("fake_function");
this->memory_.SetMemory(0x2040, fake_name.c_str(), fake_name.size() + 1);
// First verify that we can get the name.
std::string name;
uint64_t func_offset;
ASSERT_TRUE(symbols.GetName<TypeParam>(0x5000, &this->memory_, &name, &func_offset));
ASSERT_EQ("fake_function", name);
ASSERT_EQ(0U, func_offset);
// Now modify the info field so it's no longer a function.
sym.st_info = 0;
this->memory_.SetMemory(offset, &sym, sizeof(sym));
// Clear the cache to force the symbol data to be re-read.
symbols.ClearCache();
ASSERT_FALSE(symbols.GetName<TypeParam>(0x5000, &this->memory_, &name, &func_offset));
// Set the function back, and set the shndx to UNDEF.
sym.st_info = STT_FUNC;
sym.st_shndx = SHN_UNDEF;
this->memory_.SetMemory(offset, &sym, sizeof(sym));
// Clear the cache to force the symbol data to be re-read.
symbols.ClearCache();
ASSERT_FALSE(symbols.GetName<TypeParam>(0x5000, &this->memory_, &name, &func_offset));
}
TYPED_TEST_P(SymbolsTest, multiple_entries) {
Symbols symbols(0x1000, sizeof(TypeParam) * 3, sizeof(TypeParam), 0x2000, 0x500);
TypeParam sym;
uint64_t offset = 0x1000;
std::string fake_name;
this->InitSym(&sym, 0x5000, 0x10, 0x40);
this->memory_.SetMemory(offset, &sym, sizeof(sym));
fake_name = "function_one";
this->memory_.SetMemory(0x2040, fake_name.c_str(), fake_name.size() + 1);
offset += sizeof(sym);
this->InitSym(&sym, 0x3004, 0x200, 0x100);
this->memory_.SetMemory(offset, &sym, sizeof(sym));
fake_name = "function_two";
this->memory_.SetMemory(0x2100, fake_name.c_str(), fake_name.size() + 1);
offset += sizeof(sym);
this->InitSym(&sym, 0xa010, 0x20, 0x230);
this->memory_.SetMemory(offset, &sym, sizeof(sym));
fake_name = "function_three";
this->memory_.SetMemory(0x2230, fake_name.c_str(), fake_name.size() + 1);
std::string name;
uint64_t func_offset;
ASSERT_TRUE(symbols.GetName<TypeParam>(0x3005, &this->memory_, &name, &func_offset));
ASSERT_EQ("function_two", name);
ASSERT_EQ(1U, func_offset);
name.clear();
ASSERT_TRUE(symbols.GetName<TypeParam>(0x5004, &this->memory_, &name, &func_offset));
ASSERT_EQ("function_one", name);
ASSERT_EQ(4U, func_offset);
name.clear();
ASSERT_TRUE(symbols.GetName<TypeParam>(0xa011, &this->memory_, &name, &func_offset));
ASSERT_EQ("function_three", name);
ASSERT_EQ(1U, func_offset);
// Reget some of the others to verify getting one function name doesn't
// affect any of the next calls.
name.clear();
ASSERT_TRUE(symbols.GetName<TypeParam>(0x5008, &this->memory_, &name, &func_offset));
ASSERT_EQ("function_one", name);
ASSERT_EQ(8U, func_offset);
name.clear();
ASSERT_TRUE(symbols.GetName<TypeParam>(0x3008, &this->memory_, &name, &func_offset));
ASSERT_EQ("function_two", name);
ASSERT_EQ(4U, func_offset);
name.clear();
ASSERT_TRUE(symbols.GetName<TypeParam>(0xa01a, &this->memory_, &name, &func_offset));
ASSERT_EQ("function_three", name);
ASSERT_EQ(0xaU, func_offset);
}
TYPED_TEST_P(SymbolsTest, multiple_entries_nonstandard_size) {
uint64_t entry_size = sizeof(TypeParam) + 5;
Symbols symbols(0x1000, entry_size * 3, entry_size, 0x2000, 0x500);
TypeParam sym;
uint64_t offset = 0x1000;
std::string fake_name;
this->InitSym(&sym, 0x5000, 0x10, 0x40);
this->memory_.SetMemory(offset, &sym, sizeof(sym));
fake_name = "function_one";
this->memory_.SetMemory(0x2040, fake_name.c_str(), fake_name.size() + 1);
offset += entry_size;
this->InitSym(&sym, 0x3004, 0x200, 0x100);
this->memory_.SetMemory(offset, &sym, sizeof(sym));
fake_name = "function_two";
this->memory_.SetMemory(0x2100, fake_name.c_str(), fake_name.size() + 1);
offset += entry_size;
this->InitSym(&sym, 0xa010, 0x20, 0x230);
this->memory_.SetMemory(offset, &sym, sizeof(sym));
fake_name = "function_three";
this->memory_.SetMemory(0x2230, fake_name.c_str(), fake_name.size() + 1);
std::string name;
uint64_t func_offset;
ASSERT_TRUE(symbols.GetName<TypeParam>(0x3005, &this->memory_, &name, &func_offset));
ASSERT_EQ("function_two", name);
ASSERT_EQ(1U, func_offset);
name.clear();
ASSERT_TRUE(symbols.GetName<TypeParam>(0x5004, &this->memory_, &name, &func_offset));
ASSERT_EQ("function_one", name);
ASSERT_EQ(4U, func_offset);
name.clear();
ASSERT_TRUE(symbols.GetName<TypeParam>(0xa011, &this->memory_, &name, &func_offset));
ASSERT_EQ("function_three", name);
ASSERT_EQ(1U, func_offset);
}
TYPED_TEST_P(SymbolsTest, symtab_value_out_of_bounds) {
Symbols symbols_end_at_100(0x1000, sizeof(TypeParam) * 2, sizeof(TypeParam), 0x2000, 0x100);
Symbols symbols_end_at_200(0x1000, sizeof(TypeParam) * 2, sizeof(TypeParam), 0x2000, 0x200);
TypeParam sym;
uint64_t offset = 0x1000;
this->InitSym(&sym, 0x5000, 0x10, 0xfb);
this->memory_.SetMemory(offset, &sym, sizeof(sym));
offset += sizeof(sym);
this->InitSym(&sym, 0x3000, 0x10, 0x100);
this->memory_.SetMemory(offset, &sym, sizeof(sym));
// Put the name across the end of the tab.
std::string fake_name("fake_function");
this->memory_.SetMemory(0x20fb, fake_name.c_str(), fake_name.size() + 1);
std::string name;
uint64_t func_offset;
// Verify that we can get the function name properly for both entries.
ASSERT_TRUE(symbols_end_at_200.GetName<TypeParam>(0x5000, &this->memory_, &name, &func_offset));
ASSERT_EQ("fake_function", name);
ASSERT_EQ(0U, func_offset);
ASSERT_TRUE(symbols_end_at_200.GetName<TypeParam>(0x3000, &this->memory_, &name, &func_offset));
ASSERT_EQ("function", name);
ASSERT_EQ(0U, func_offset);
// Now use the symbol table that ends at 0x100.
ASSERT_FALSE(symbols_end_at_100.GetName<TypeParam>(0x5000, &this->memory_, &name, &func_offset));
ASSERT_FALSE(symbols_end_at_100.GetName<TypeParam>(0x3000, &this->memory_, &name, &func_offset));
}
// Verify the entire func table is cached.
TYPED_TEST_P(SymbolsTest, symtab_read_cached) {
Symbols symbols(0x1000, 3 * sizeof(TypeParam), sizeof(TypeParam), 0xa000, 0x1000);
TypeParam sym;
uint64_t offset = 0x1000;
// Make sure that these entries are not in ascending order.
this->InitSym(&sym, 0x5000, 0x10, 0x100);
this->memory_.SetMemory(offset, &sym, sizeof(sym));
offset += sizeof(sym);
this->InitSym(&sym, 0x2000, 0x300, 0x200);
this->memory_.SetMemory(offset, &sym, sizeof(sym));
offset += sizeof(sym);
this->InitSym(&sym, 0x1000, 0x100, 0x300);
this->memory_.SetMemory(offset, &sym, sizeof(sym));
offset += sizeof(sym);
// Do call that should cache all of the entries (except the string data).
std::string name;
uint64_t func_offset;
ASSERT_FALSE(symbols.GetName<TypeParam>(0x6000, &this->memory_, &name, &func_offset));
this->memory_.Clear();
ASSERT_FALSE(symbols.GetName<TypeParam>(0x6000, &this->memory_, &name, &func_offset));
// Clear the memory and only put the symbol data string data in memory.
this->memory_.Clear();
std::string fake_name;
fake_name = "first_entry";
this->memory_.SetMemory(0xa100, fake_name.c_str(), fake_name.size() + 1);
fake_name = "second_entry";
this->memory_.SetMemory(0xa200, fake_name.c_str(), fake_name.size() + 1);
fake_name = "third_entry";
this->memory_.SetMemory(0xa300, fake_name.c_str(), fake_name.size() + 1);
ASSERT_TRUE(symbols.GetName<TypeParam>(0x5001, &this->memory_, &name, &func_offset));
ASSERT_EQ("first_entry", name);
ASSERT_EQ(1U, func_offset);
ASSERT_TRUE(symbols.GetName<TypeParam>(0x2002, &this->memory_, &name, &func_offset));
ASSERT_EQ("second_entry", name);
ASSERT_EQ(2U, func_offset);
ASSERT_TRUE(symbols.GetName<TypeParam>(0x1003, &this->memory_, &name, &func_offset));
ASSERT_EQ("third_entry", name);
ASSERT_EQ(3U, func_offset);
}
TYPED_TEST_P(SymbolsTest, get_global) {
uint64_t start_offset = 0x1000;
uint64_t str_offset = 0xa000;
Symbols symbols(start_offset, 4 * sizeof(TypeParam), sizeof(TypeParam), str_offset, 0x1000);
TypeParam sym;
memset(&sym, 0, sizeof(sym));
sym.st_shndx = SHN_COMMON;
sym.st_info = STT_OBJECT | (STB_GLOBAL << 4);
sym.st_name = 0x100;
this->memory_.SetMemory(start_offset, &sym, sizeof(sym));
this->memory_.SetMemory(str_offset + 0x100, "global_0");
start_offset += sizeof(sym);
memset(&sym, 0, sizeof(sym));
sym.st_shndx = SHN_COMMON;
sym.st_info = STT_FUNC;
sym.st_name = 0x200;
sym.st_value = 0x10000;
sym.st_size = 0x100;
this->memory_.SetMemory(start_offset, &sym, sizeof(sym));
this->memory_.SetMemory(str_offset + 0x200, "function_0");
start_offset += sizeof(sym);
memset(&sym, 0, sizeof(sym));
sym.st_shndx = SHN_COMMON;
sym.st_info = STT_OBJECT | (STB_GLOBAL << 4);
sym.st_name = 0x300;
this->memory_.SetMemory(start_offset, &sym, sizeof(sym));
this->memory_.SetMemory(str_offset + 0x300, "global_1");
start_offset += sizeof(sym);
memset(&sym, 0, sizeof(sym));
sym.st_shndx = SHN_COMMON;
sym.st_info = STT_FUNC;
sym.st_name = 0x400;
sym.st_value = 0x12000;
sym.st_size = 0x100;
this->memory_.SetMemory(start_offset, &sym, sizeof(sym));
this->memory_.SetMemory(str_offset + 0x400, "function_1");
uint64_t offset;
EXPECT_TRUE(symbols.GetGlobal<TypeParam>(&this->memory_, "global_0", &offset));
EXPECT_TRUE(symbols.GetGlobal<TypeParam>(&this->memory_, "global_1", &offset));
EXPECT_TRUE(symbols.GetGlobal<TypeParam>(&this->memory_, "global_0", &offset));
EXPECT_TRUE(symbols.GetGlobal<TypeParam>(&this->memory_, "global_1", &offset));
EXPECT_FALSE(symbols.GetGlobal<TypeParam>(&this->memory_, "function_0", &offset));
EXPECT_FALSE(symbols.GetGlobal<TypeParam>(&this->memory_, "function_1", &offset));
std::string name;
EXPECT_TRUE(symbols.GetName<TypeParam>(0x10002, &this->memory_, &name, &offset));
EXPECT_EQ("function_0", name);
EXPECT_EQ(2U, offset);
EXPECT_TRUE(symbols.GetName<TypeParam>(0x12004, &this->memory_, &name, &offset));
EXPECT_EQ("function_1", name);
EXPECT_EQ(4U, offset);
}
REGISTER_TYPED_TEST_CASE_P(SymbolsTest, function_bounds_check, no_symbol, multiple_entries,
multiple_entries_nonstandard_size, symtab_value_out_of_bounds,
symtab_read_cached, get_global);
typedef ::testing::Types<Elf32_Sym, Elf64_Sym> SymbolsTestTypes;
INSTANTIATE_TYPED_TEST_CASE_P(, SymbolsTest, SymbolsTestTypes);
} // namespace unwindstack
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