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Merge "Add execinfo functionality." am: dc4b3789e6

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Original change: https://android-review.googlesource.com/c/platform/bionic/+/1863333

Change-Id: I1222ecc6e8ddef5ae7647d63416098c32241c157
This commit is contained in:
Christopher Ferris 2021-10-21 00:42:10 +00:00 committed by Automerger Merge Worker
commit d7ab5c45d6
7 changed files with 542 additions and 0 deletions
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1
libc/Android.bp
View file

@ -1054,6 +1054,7 @@ cc_library_static {
"bionic/error.cpp",
"bionic/eventfd.cpp",
"bionic/exec.cpp",
"bionic/execinfo.cpp",
"bionic/faccessat.cpp",
"bionic/fchmod.cpp",
"bionic/fchmodat.cpp",

187
libc/bionic/execinfo.cpp Normal file
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@ -0,0 +1,187 @@
/*
* Copyright (C) 2012 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <dlfcn.h>
#include <execinfo.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>
#include <unwind.h>
#include "private/ScopedFd.h"
struct StackState {
void** frames;
int frame_count;
int cur_frame = 0;
StackState(void** frames, int frame_count) : frames(frames), frame_count(frame_count) {}
};
static _Unwind_Reason_Code TraceFunction(_Unwind_Context* context, void* arg) {
// The instruction pointer is pointing at the instruction after the return
// call on all architectures.
// Modify the pc to point at the real function.
uintptr_t ip = _Unwind_GetIP(context);
if (ip != 0) {
#if defined(__arm__)
// If the ip is suspiciously low, do nothing to avoid a segfault trying
// to access this memory.
if (ip >= 4096) {
// Check bits [15:11] of the first halfword assuming the instruction
// is 32 bits long. If the bits are any of these values, then our
// assumption was correct:
// b11101
// b11110
// b11111
// Otherwise, this is a 16 bit instruction.
uint16_t value = (*reinterpret_cast<uint16_t*>(ip - 2)) >> 11;
if (value == 0x1f || value == 0x1e || value == 0x1d) {
ip -= 4;
} else {
ip -= 2;
}
}
#elif defined(__aarch64__)
// All instructions are 4 bytes long, skip back one instruction.
ip -= 4;
#elif defined(__i386__) || defined(__x86_64__)
// It's difficult to decode exactly where the previous instruction is,
// so subtract 1 to estimate where the instruction lives.
ip--;
#endif
}
StackState* state = static_cast<StackState*>(arg);
state->frames[state->cur_frame++] = reinterpret_cast<void*>(ip);
return (state->cur_frame >= state->frame_count) ? _URC_END_OF_STACK : _URC_NO_REASON;
}
int backtrace(void** buffer, int size) {
if (size <= 0) {
return 0;
}
StackState state(buffer, size);
_Unwind_Backtrace(TraceFunction, &state);
return state.cur_frame;
}
char** backtrace_symbols(void* const* buffer, int size) {
if (size <= 0) {
return nullptr;
}
// Do this calculation first in case the user passes in a bad value.
size_t ptr_size;
if (__builtin_mul_overflow(sizeof(char*), size, &ptr_size)) {
return nullptr;
}
ScopedFd fd(memfd_create("backtrace_symbols_fd", MFD_CLOEXEC));
if (fd.get() == -1) {
return nullptr;
}
backtrace_symbols_fd(buffer, size, fd.get());
// Get the size of the file.
off_t file_size = lseek(fd.get(), 0, SEEK_END);
if (file_size <= 0) {
return nullptr;
}
// The interface for backtrace_symbols indicates that only the single
// returned pointer must be freed by the caller. Therefore, allocate a
// buffer that includes the memory for the strings and all of the pointers.
// Add one byte at the end just in case the file didn't end with a '\n'.
size_t symbol_data_size;
if (__builtin_add_overflow(ptr_size, file_size, &symbol_data_size) ||
__builtin_add_overflow(symbol_data_size, 1, &symbol_data_size)) {
return nullptr;
}
uint8_t* symbol_data = reinterpret_cast<uint8_t*>(malloc(symbol_data_size));
if (symbol_data == nullptr) {
return nullptr;
}
// Copy the string data into the buffer.
char* cur_string = reinterpret_cast<char*>(&symbol_data[ptr_size]);
// If this fails, the read won't read back the correct number of bytes.
lseek(fd.get(), 0, SEEK_SET);
ssize_t num_read = read(fd.get(), cur_string, file_size);
fd.reset(-1);
if (num_read != file_size) {
free(symbol_data);
return nullptr;
}
// Make sure the last character in the file is '\n'.
if (cur_string[file_size] != '\n') {
cur_string[file_size++] = '\n';
}
for (int i = 0; i < size; i++) {
(reinterpret_cast<char**>(symbol_data))[i] = cur_string;
cur_string = strchr(cur_string, '\n');
if (cur_string == nullptr) {
free(symbol_data);
return nullptr;
}
cur_string[0] = '\0';
cur_string++;
}
return reinterpret_cast<char**>(symbol_data);
}
// This function should do no allocations if possible.
void backtrace_symbols_fd(void* const* buffer, int size, int fd) {
if (size <= 0 || fd < 0) {
return;
}
for (int frame_num = 0; frame_num < size; frame_num++) {
void* address = buffer[frame_num];
Dl_info info;
if (dladdr(address, &info) != 0) {
if (info.dli_fname != nullptr) {
write(fd, info.dli_fname, strlen(info.dli_fname));
}
if (info.dli_sname != nullptr) {
dprintf(fd, "(%s+0x%" PRIxPTR ") ", info.dli_sname,
reinterpret_cast<uintptr_t>(address) - reinterpret_cast<uintptr_t>(info.dli_saddr));
} else {
dprintf(fd, "(+%p) ", info.dli_saddr);
}
}
dprintf(fd, "[%p]\n", address);
}
}

74
libc/include/execinfo.h Normal file
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@ -0,0 +1,74 @@
/*
* Copyright (C) 2021 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#pragma once
#include <sys/cdefs.h>
/**
* @file execinfo.h
* @brief Functions to do in process backtracing.
*/
__BEGIN_DECLS
/**
* [backtrace(3)](https://man7.org/linux/man-pages/man3/backtrace.3.html)
* Saves a backtrace for the current call in the array pointed to by buffer.
* "size" indicates the maximum number of void* pointers that can be set.
*
* Returns the number of addresses stored in "buffer", which is not greater
* than "size". If the return value is equal to "size" then the number of
* addresses may have been truncated.
*
* Available since API level 33.
*/
int backtrace(void** buffer, int size) __INTRODUCED_IN(33);
/**
* [backtrace_symbols(3)](https://man7.org/linux/man-pages/man3/backtrace_symbols.3.html)
* Given an array of void* pointers, translate the addresses into an array
* of strings that represent the backtrace.
*
* Returns a pointer to allocated memory, on error NULL is returned. It is
* the responsibility of the caller to free the returned memory.
*
* Available since API level 33.
*/
char** backtrace_symbols(void* const* buffer, int size) __INTRODUCED_IN(33);
/**
* [backtrace_symbols_fd(3)](https://man7.org/linux/man-pages/man3/backtrace_symbols_fd.3.html)
* Given an array of void* pointers, translate the addresses into an array
* of strings that represent the backtrace and write to the file represented
* by "fd". The file is written such that one line equals one void* address.
*
* Available since API level 33.
*/
void backtrace_symbols_fd(void* const* buffer, int size, int fd) __INTRODUCED_IN(33);
__END_DECLS

3
libc/libc.map.txt
View file

@ -1567,6 +1567,9 @@ LIBC_S { # introduced=S
LIBC_T { # introduced=Tiramisu
global:
backtrace;
backtrace_symbols;
backtrace_symbols_fd;
preadv2;
preadv64v2;
pwritev2;

5
tests/Android.bp
View file

@ -474,6 +474,9 @@ cc_test_library {
// musl doesn't have error.h
"error_test.cpp",
// musl doesn't have execinfo.h
"execinfo_test.cpp",
// musl doesn't define noreturn for C++
"stdnoreturn_test.cpp",
@ -745,6 +748,7 @@ cc_test_library {
"dl_test.cpp",
"dlfcn_symlink_support.cpp",
"dlfcn_test.cpp",
"execinfo_test.cpp",
"link_test.cpp",
"pthread_dlfcn_test.cpp",
],
@ -1141,6 +1145,7 @@ cc_test_host {
"dlfcn_symlink_support.cpp",
"dlfcn_test.cpp",
"dl_test.cpp",
"execinfo_test.cpp",
"gtest_globals.cpp",
"gtest_main.cpp",
"pthread_dlfcn_test.cpp",

28
tests/NOTICE
View file

@ -354,3 +354,31 @@ limitations under the License.
-------------------------------------------------------------------
Copyright (C) 2021 The Android Open Source Project
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
-------------------------------------------------------------------

244
tests/execinfo_test.cpp Normal file
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@ -0,0 +1,244 @@
/*
* Copyright (C) 2021 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <gtest/gtest.h>
#include <dlfcn.h>
#include <execinfo.h>
#include <string.h>
#include <fstream>
#include <regex>
#include <string>
#include <vector>
#include <android-base/file.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/test_utils.h>
TEST(execinfo, backtrace_errors) {
void* frames[20];
ASSERT_EQ(0, backtrace(frames, 0));
ASSERT_EQ(0, backtrace(frames, -1));
}
static constexpr int kMaxFrames = 50;
// Disable optimizations so that these functions show up properly in
// the backtrace.
#pragma clang optimize off
extern "C" __attribute__((__noinline__)) void CallTwo(std::vector<void*>& frames) {
int num_frames = backtrace(frames.data(), static_cast<int>(frames.size()));
ASSERT_LT(0, num_frames);
frames.resize(static_cast<size_t>(num_frames));
}
extern "C" __attribute__((__noinline__)) void CallOne(std::vector<void*>& frames) {
CallTwo(frames);
}
#pragma clang optimize on
static std::string DumpFrames(std::vector<void*>& frames) {
std::string frame_data;
for (auto frame : frames) {
frame_data += android::base::StringPrintf("[%p]", frame);
Dl_info info;
if (dladdr(frame, &info) != 0 && info.dli_sname != nullptr) {
frame_data += ' ';
frame_data += info.dli_sname;
}
frame_data += '\n';
}
return frame_data;
}
static size_t FindFunction(std::vector<void*>& frames, uintptr_t func_addr) {
for (size_t i = 0; i < frames.size(); i++) {
uintptr_t frame_addr = reinterpret_cast<uintptr_t>(frames[i]);
if (frame_addr >= func_addr && frame_addr <= func_addr + 0x100) {
return i + 1;
}
}
return 0;
}
static void VerifyCalls(std::vector<void*>& frames, size_t* one_idx = nullptr,
size_t* two_idx = nullptr) {
// Try and find the CallOne and CallTwo function addresses.
size_t call_one_idx = FindFunction(frames, reinterpret_cast<uintptr_t>(&CallOne));
ASSERT_TRUE(call_one_idx != 0) << DumpFrames(frames);
size_t call_two_idx = FindFunction(frames, reinterpret_cast<uintptr_t>(&CallTwo));
ASSERT_TRUE(call_two_idx != 0) << DumpFrames(frames);
ASSERT_LT(call_two_idx, call_one_idx) << "CallTwo function found after CallOne\n"
<< DumpFrames(frames);
if (one_idx != nullptr) *one_idx = call_one_idx;
if (two_idx != nullptr) *two_idx = call_two_idx;
}
TEST(execinfo, backtrace) {
std::vector<void*> frames(kMaxFrames);
ASSERT_NO_FATAL_FAILURE(CallOne(frames));
// Verfiy that there are at least two frames.
ASSERT_LT(3U, frames.size()) << DumpFrames(frames);
VerifyCalls(frames);
}
TEST(execinfo, backtrace_cutoff_frames) {
// Verify the max frames is handled properly
std::vector<void*> frames(1);
ASSERT_NO_FATAL_FAILURE(CallOne(frames));
ASSERT_EQ(1U, frames.size()) << DumpFrames(frames);
}
TEST(execinfo, backtrace_symbols_errors) {
void* frames[kMaxFrames];
// glibc incorrectly returns memory when a zero is passed in.
// Since we know this works properly on bionic, only verify
// this there.
#if defined(__BIONIC__)
ASSERT_EQ(nullptr, backtrace_symbols(frames, 0));
#endif
ASSERT_EQ(nullptr, backtrace_symbols(frames, -1));
}
static void VerifyLineFormat(std::string& line) {
// Verify that the format of the line is one of these:
// elf_file(FuncName+0xFuncAddr) [0xAddress]
// elf_file(+0xRelAddress) [0xAddress]
// elf_file [0xAddress]
// [0xAddress]
#if defined(__GLIBC__)
// For some reason, glibc will print a space before [0xAddress] for
// backtrace symbols, and no space for backtrace_symbols_fd. Allow this
// only for glibc.
std::regex format1("[^\\(\\s]+\\([^\\+]+\\+0x[0-9a-fA-F]+\\) ?\\[0x[0-9a-fA-F]+\\]");
std::regex format2("[^\\(\\s]+\\(+\\+0x[0-9a-fA-F]+\\) ?\\[0x[0-9a-fA-F]+\\]");
std::regex format3("[^\\(\\s]+ ?\\[0x[0-9a-fA-F]+\\]");
#else
std::regex format1("[^\\(\\s]+\\([^\\+]+\\+0x[0-9a-fA-F]+\\) \\[0x[0-9a-fA-F]+\\]");
std::regex format2("[^\\(\\s]+\\(+\\+0x[0-9a-fA-F]+\\) \\[0x[0-9a-fA-F]+\\]");
std::regex format3("[^\\(\\s]+ \\[0x[0-9a-fA-F]+\\]");
#endif
std::regex format4("\\[0x[0-9a-fA-F]+\\]");
EXPECT_TRUE(std::regex_match(line, format1) || std::regex_match(line, format2) ||
std::regex_match(line, format3) || std::regex_match(line, format4))
<< "Unknown format of line:\n"
<< line;
}
static void VerifyLineFormat(char* raw_line, size_t length) {
std::string line(raw_line, length);
VerifyLineFormat(line);
}
TEST(execinfo, backtrace_symbols) {
std::vector<void*> frames(kMaxFrames);
ASSERT_NO_FATAL_FAILURE(CallOne(frames));
ASSERT_LT(3U, frames.size()) << DumpFrames(frames);
char** symbols = backtrace_symbols(frames.data(), static_cast<int>(frames.size()));
ASSERT_TRUE(symbols != nullptr);
for (size_t i = 0; i < frames.size(); i++) {
ASSERT_TRUE(frames[i] != nullptr);
VerifyLineFormat(symbols[i], strlen(symbols[i]));
}
size_t call_one_idx;
size_t call_two_idx;
ASSERT_NO_FATAL_FAILURE(VerifyCalls(frames, &call_one_idx, &call_two_idx));
// Now verify that those frames contain the function names we expect.
SCOPED_TRACE(DumpFrames(frames));
ASSERT_MATCH(symbols[call_one_idx - 1], "\\(CallOne+");
ASSERT_MATCH(symbols[call_two_idx - 1], "\\(CallTwo+");
free(symbols);
}
TEST(execinfo, backtrace_symbols_fd_errors) {
void* frames[kMaxFrames];
frames[0] = reinterpret_cast<void*>(&backtrace_symbols);
{
TemporaryFile tf;
backtrace_symbols_fd(frames, 0, tf.fd);
close(tf.fd);
std::string content;
ASSERT_TRUE(android::base::ReadFileToString(tf.path, &content));
// Verify that no data is written to the file.
ASSERT_TRUE(content.empty());
}
{
TemporaryFile tf;
backtrace_symbols_fd(frames, -1, tf.fd);
close(tf.fd);
std::string content;
ASSERT_TRUE(android::base::ReadFileToString(tf.path, &content));
// Verify that no data is written to the file.
ASSERT_TRUE(content.empty());
}
// Verify that there isn't a crash.
backtrace_symbols_fd(frames, 0, -1);
}
TEST(execinfo, backtrace_symbols_fd) {
std::vector<void*> frames(kMaxFrames);
ASSERT_NO_FATAL_FAILURE(CallOne(frames));
ASSERT_LT(3U, frames.size()) << DumpFrames(frames);
TemporaryFile tf;
backtrace_symbols_fd(frames.data(), static_cast<int>(frames.size()), tf.fd);
close(tf.fd);
size_t call_one_idx;
size_t call_two_idx;
ASSERT_NO_FATAL_FAILURE(VerifyCalls(frames, &call_one_idx, &call_two_idx));
std::ifstream frame_stream(tf.path);
ASSERT_TRUE(frame_stream.is_open());
size_t num_lines = 0;
std::string line;
while (std::getline(frame_stream, line)) {
ASSERT_FALSE(line.empty());
VerifyLineFormat(line);
num_lines++;
if (num_lines == call_one_idx) {
EXPECT_MATCH(line, "\\(CallOne+");
} else if (num_lines == call_two_idx) {
EXPECT_MATCH(line, "\\(CallTwo+");
}
}
ASSERT_EQ(num_lines, frames.size()) << "Number of lines in file does not match number of frames.";
}