Merge "Workaround Clang cannot build ifunc with LTO"
diff --git a/libc/Android.bp b/libc/Android.bp
index 2a8df9a..ee8c280 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -1054,6 +1054,7 @@
"bionic/error.cpp",
"bionic/eventfd.cpp",
"bionic/exec.cpp",
+ "bionic/execinfo.cpp",
"bionic/faccessat.cpp",
"bionic/fchmod.cpp",
"bionic/fchmodat.cpp",
diff --git a/libc/bionic/execinfo.cpp b/libc/bionic/execinfo.cpp
new file mode 100644
index 0000000..d129f7c
--- /dev/null
+++ b/libc/bionic/execinfo.cpp
@@ -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);
+ }
+}
diff --git a/libc/include/execinfo.h b/libc/include/execinfo.h
new file mode 100644
index 0000000..347ae92
--- /dev/null
+++ b/libc/include/execinfo.h
@@ -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
diff --git a/libc/libc.map.txt b/libc/libc.map.txt
index 12b8114..00b25d3 100644
--- a/libc/libc.map.txt
+++ b/libc/libc.map.txt
@@ -1567,6 +1567,9 @@
LIBC_T { # introduced=Tiramisu
global:
+ backtrace;
+ backtrace_symbols;
+ backtrace_symbols_fd;
preadv2;
preadv64v2;
pwritev2;
diff --git a/tests/Android.bp b/tests/Android.bp
index 355f396..e7273c0 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -474,6 +474,9 @@
// 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 @@
"dl_test.cpp",
"dlfcn_symlink_support.cpp",
"dlfcn_test.cpp",
+ "execinfo_test.cpp",
"link_test.cpp",
"pthread_dlfcn_test.cpp",
],
@@ -1146,6 +1150,7 @@
"dlfcn_symlink_support.cpp",
"dlfcn_test.cpp",
"dl_test.cpp",
+ "execinfo_test.cpp",
"gtest_globals.cpp",
"gtest_main.cpp",
"pthread_dlfcn_test.cpp",
diff --git a/tests/NOTICE b/tests/NOTICE
index a58cf46..c9b65d0 100644
--- a/tests/NOTICE
+++ b/tests/NOTICE
@@ -354,3 +354,31 @@
-------------------------------------------------------------------
+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.
+
+-------------------------------------------------------------------
+
diff --git a/tests/execinfo_test.cpp b/tests/execinfo_test.cpp
new file mode 100644
index 0000000..b8e1325
--- /dev/null
+++ b/tests/execinfo_test.cpp
@@ -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.";
+}
