1 files changed, 244 insertions, 0 deletions
diff --git a/tests/execinfo_test.cpp b/tests/execinfo_test.cpp
new file mode 100644
index 000000000..b8e13252d
--- /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.";
+}