debuggerd: advance our amazing bet.

Remove debuggerd in favor of a helper process that gets execed by
crashing processes.

Bug: http://b/30705528
Test: debuggerd_test
Change-Id: I9906c69473989cbf7fe5ea6cccf9a9c563d75906

1 files changed, 390 insertions, 0 deletions

diff --git a/debuggerd/debuggerd_test.cpp b/debuggerd/debuggerd_test.cpp
new file mode 100644
index 000000000..f51b5f253
--- /dev/null
+++ b/debuggerd/debuggerd_test.cpp
@@ -0,0 +1,390 @@
+/*
+ * Copyright 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 <err.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+#include <chrono>
+#include <regex>
+#include <thread>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
+#include <android-base/properties.h>
+#include <android-base/strings.h>
+#include <android-base/unique_fd.h>
+#include <cutils/sockets.h>
+#include <debuggerd/handler.h>
+#include <debuggerd/protocol.h>
+#include <debuggerd/util.h>
+#include <gtest/gtest.h>
+
+using namespace std::chrono_literals;
+using android::base::unique_fd;
+
+#if defined(__LP64__)
+#define CRASHER_PATH  "/system/xbin/crasher64"
+#define ARCH_SUFFIX "64"
+#else
+#define CRASHER_PATH "/system/xbin/crasher"
+#define ARCH_SUFFIX ""
+#endif
+
+constexpr char kWaitForGdbKey[] = "debug.debuggerd.wait_for_gdb";
+
+#define TIMEOUT(seconds, expr)                                     \
+  [&]() {                                                          \
+    struct sigaction old_sigaction;                                \
+    struct sigaction new_sigaction = {};                           \
+    new_sigaction.sa_handler = [](int) {};                         \
+    if (sigaction(SIGALRM, &new_sigaction, &new_sigaction) != 0) { \
+      err(1, "sigaction failed");                                  \
+    }                                                              \
+    alarm(seconds);                                                \
+    auto value = expr;                                             \
+    int saved_errno = errno;                                       \
+    if (sigaction(SIGALRM, &old_sigaction, nullptr) != 0) {        \
+      err(1, "sigaction failed");                                  \
+    }                                                              \
+    alarm(0);                                                      \
+    errno = saved_errno;                                           \
+    return value;                                                  \
+  }()
+
+#define ASSERT_MATCH(str, pattern)                                              \
+  do {                                                                          \
+    std::regex r((pattern));                                                    \
+    if (!std::regex_search((str), r)) {                                         \
+      FAIL() << "regex mismatch: expected " << (pattern) << " in: \n" << (str); \
+    }                                                                           \
+  } while (0)
+
+class CrasherTest : public ::testing::Test {
+ public:
+  pid_t crasher_pid = -1;
+  bool previous_wait_for_gdb;
+  unique_fd crasher_pipe;
+  unique_fd intercept_fd;
+
+  CrasherTest();
+  ~CrasherTest();
+
+  void StartIntercept(unique_fd* output_fd);
+
+  // Returns -1 if we fail to read a response from tombstoned, otherwise the received return code.
+  void FinishIntercept(int* result);
+
+  void StartCrasher(const std::string& crash_type);
+  void FinishCrasher();
+  void AssertDeath(int signo);
+};
+
+CrasherTest::CrasherTest() {
+  previous_wait_for_gdb = android::base::GetBoolProperty(kWaitForGdbKey, false);
+  android::base::SetProperty(kWaitForGdbKey, "0");
+}
+
+CrasherTest::~CrasherTest() {
+  if (crasher_pid != -1) {
+    kill(crasher_pid, SIGKILL);
+    int status;
+    waitpid(crasher_pid, &status, WUNTRACED);
+  }
+
+  android::base::SetProperty(kWaitForGdbKey, previous_wait_for_gdb ? "1" : "0");
+}
+
+void CrasherTest::StartIntercept(unique_fd* output_fd) {
+  if (crasher_pid == -1) {
+    FAIL() << "crasher hasn't been started";
+  }
+
+  intercept_fd.reset(socket_local_client(kTombstonedInterceptSocketName,
+                                         ANDROID_SOCKET_NAMESPACE_RESERVED, SOCK_SEQPACKET));
+  if (intercept_fd == -1) {
+    FAIL() << "failed to contact tombstoned: " << strerror(errno);
+  }
+
+  InterceptRequest req = {.pid = crasher_pid };
+
+  unique_fd output_pipe_write;
+  if (!Pipe(output_fd, &output_pipe_write)) {
+    FAIL() << "failed to create output pipe: " << strerror(errno);
+  }
+
+  std::string pipe_size_str;
+  int pipe_buffer_size;
+  if (!android::base::ReadFileToString("/proc/sys/fs/pipe-max-size", &pipe_size_str)) {
+    FAIL() << "failed to read /proc/sys/fs/pipe-max-size: " << strerror(errno);
+  }
+
+  pipe_size_str = android::base::Trim(pipe_size_str);
+
+  if (!android::base::ParseInt(pipe_size_str.c_str(), &pipe_buffer_size, 0)) {
+    FAIL() << "failed to parse pipe max size";
+  }
+
+  if (fcntl(output_fd->get(), F_SETPIPE_SZ, pipe_buffer_size) != pipe_buffer_size) {
+    FAIL() << "failed to set pipe size: " << strerror(errno);
+  }
+
+  if (send_fd(intercept_fd.get(), &req, sizeof(req), std::move(output_pipe_write)) != sizeof(req)) {
+    FAIL() << "failed to send output fd to tombstoned: " << strerror(errno);
+  }
+}
+
+void CrasherTest::FinishIntercept(int* result) {
+  InterceptResponse response;
+
+  // Timeout for tombstoned intercept is 10 seconds.
+  ssize_t rc = TIMEOUT(20, read(intercept_fd.get(), &response, sizeof(response)));
+  if (rc == -1) {
+    FAIL() << "failed to read response from tombstoned: " << strerror(errno);
+  } else if (rc == 0) {
+    *result = -1;
+  } else if (rc != sizeof(response)) {
+    FAIL() << "received packet of unexpected length from tombstoned: expected " << sizeof(response)
+           << ", received " << rc;
+  } else {
+    *result = response.success;
+  }
+}
+
+void CrasherTest::StartCrasher(const std::string& crash_type) {
+  std::string type = "wait-" + crash_type;
+
+  unique_fd crasher_read_pipe;
+  if (!Pipe(&crasher_read_pipe, &crasher_pipe)) {
+    FAIL() << "failed to create pipe: " << strerror(errno);
+  }
+
+  crasher_pid = fork();
+  if (crasher_pid == -1) {
+    FAIL() << "fork failed: " << strerror(errno);
+  } else if (crasher_pid == 0) {
+    unique_fd devnull(open("/dev/null", O_WRONLY));
+    dup2(crasher_read_pipe.get(), STDIN_FILENO);
+    dup2(devnull.get(), STDOUT_FILENO);
+    dup2(devnull.get(), STDERR_FILENO);
+    execl(CRASHER_PATH, CRASHER_PATH, type.c_str(), nullptr);
+    err(1, "exec failed");
+  }
+}
+
+void CrasherTest::FinishCrasher() {
+  if (crasher_pipe == -1) {
+    FAIL() << "crasher pipe uninitialized";
+  }
+
+  ssize_t rc = write(crasher_pipe.get(), "\n", 1);
+  if (rc == -1) {
+    FAIL() << "failed to write to crasher pipe: " << strerror(errno);
+  } else if (rc == 0) {
+    FAIL() << "crasher pipe was closed";
+  }
+}
+
+void CrasherTest::AssertDeath(int signo) {
+  int status;
+  pid_t pid = TIMEOUT(5, waitpid(crasher_pid, &status, 0));
+  if (pid != crasher_pid) {
+    FAIL() << "failed to wait for crasher: " << strerror(errno);
+  }
+
+  if (!WIFSIGNALED(status)) {
+    FAIL() << "crasher didn't terminate via a signal";
+  }
+  ASSERT_EQ(signo, WTERMSIG(status));
+  crasher_pid = -1;
+}
+
+static void ConsumeFd(unique_fd fd, std::string* output) {
+  constexpr size_t read_length = PAGE_SIZE;
+  std::string result;
+
+  while (true) {
+    size_t offset = result.size();
+    result.resize(result.size() + PAGE_SIZE);
+    ssize_t rc = TEMP_FAILURE_RETRY(read(fd.get(), &result[offset], read_length));
+    if (rc == -1) {
+      FAIL() << "read failed: " << strerror(errno);
+    } else if (rc == 0) {
+      result.resize(result.size() - PAGE_SIZE);
+      break;
+    }
+
+    result.resize(result.size() - PAGE_SIZE + rc);
+  }
+
+  *output = std::move(result);
+}
+
+TEST_F(CrasherTest, smoke) {
+  int intercept_result;
+  unique_fd output_fd;
+  StartCrasher("SIGSEGV");
+  StartIntercept(&output_fd);
+  FinishCrasher();
+  AssertDeath(SIGSEGV);
+  FinishIntercept(&intercept_result);
+
+  ASSERT_EQ(1, intercept_result) << "tombstoned reported failure";
+
+  std::string result;
+  ConsumeFd(std::move(output_fd), &result);
+  ASSERT_MATCH(result, R"(signal 11 \(SIGSEGV\), code 1 \(SEGV_MAPERR\), fault addr 0xdead)");
+}
+
+TEST_F(CrasherTest, abort) {
+  int intercept_result;
+  unique_fd output_fd;
+  StartCrasher("abort");
+  StartIntercept(&output_fd);
+  FinishCrasher();
+  AssertDeath(SIGABRT);
+  FinishIntercept(&intercept_result);
+
+  ASSERT_EQ(1, intercept_result) << "tombstoned reported failure";
+
+  std::string result;
+  ConsumeFd(std::move(output_fd), &result);
+  ASSERT_MATCH(result, R"(#00 pc [0-9a-f]+\s+ /system/lib)" ARCH_SUFFIX R"(/libc.so \(tgkill)");
+}
+
+TEST_F(CrasherTest, signal) {
+  int intercept_result;
+  unique_fd output_fd;
+  StartCrasher("abort");
+  StartIntercept(&output_fd);
+
+  // Wait for a bit, or we might end up killing the process before the signal
+  // handler even gets a chance to be registered.
+  std::this_thread::sleep_for(100ms);
+  ASSERT_EQ(0, kill(crasher_pid, SIGSEGV));
+
+  AssertDeath(SIGSEGV);
+  FinishIntercept(&intercept_result);
+
+  ASSERT_EQ(1, intercept_result) << "tombstoned reported failure";
+
+  std::string result;
+  ConsumeFd(std::move(output_fd), &result);
+  ASSERT_MATCH(result, R"(signal 11 \(SIGSEGV\), code 0 \(SI_USER\), fault addr --------)");
+  ASSERT_MATCH(result, R"(backtrace:)");
+}
+
+TEST_F(CrasherTest, abort_message) {
+  int intercept_result;
+  unique_fd output_fd;
+  StartCrasher("smash-stack");
+  StartIntercept(&output_fd);
+  FinishCrasher();
+  AssertDeath(SIGABRT);
+  FinishIntercept(&intercept_result);
+
+  ASSERT_EQ(1, intercept_result) << "tombstoned reported failure";
+
+  std::string result;
+  ConsumeFd(std::move(output_fd), &result);
+  ASSERT_MATCH(result, R"(Abort message: 'stack corruption detected \(-fstack-protector\)')");
+}
+
+TEST_F(CrasherTest, intercept_timeout) {
+  int intercept_result;
+  unique_fd output_fd;
+  StartCrasher("abort");
+  StartIntercept(&output_fd);
+
+  // Don't let crasher finish until we timeout.
+  FinishIntercept(&intercept_result);
+
+  ASSERT_NE(1, intercept_result) << "tombstoned reported success? (intercept_result = "
+                                 << intercept_result << ")";
+
+  FinishCrasher();
+  AssertDeath(SIGABRT);
+}
+
+TEST_F(CrasherTest, wait_for_gdb) {
+  if (!android::base::SetProperty(kWaitForGdbKey, "1")) {
+    FAIL() << "failed to enable wait_for_gdb";
+  }
+  sleep(1);
+
+  StartCrasher("abort");
+  FinishCrasher();
+
+  int status;
+  ASSERT_EQ(crasher_pid, waitpid(crasher_pid, &status, WUNTRACED));
+  ASSERT_TRUE(WIFSTOPPED(status));
+  ASSERT_EQ(SIGSTOP, WSTOPSIG(status));
+
+  ASSERT_EQ(0, kill(crasher_pid, SIGCONT));
+
+  AssertDeath(SIGABRT);
+}
+
+TEST_F(CrasherTest, wait_for_gdb_signal) {
+  if (!android::base::SetProperty(kWaitForGdbKey, "1")) {
+    FAIL() << "failed to enable wait_for_gdb";
+  }
+
+  StartCrasher("abort");
+  ASSERT_EQ(0, kill(crasher_pid, SIGABRT)) << strerror(errno);
+
+  std::this_thread::sleep_for(500ms);
+
+  int status;
+  ASSERT_EQ(crasher_pid, (TIMEOUT(1, waitpid(crasher_pid, &status, WUNTRACED))));
+  ASSERT_TRUE(WIFSTOPPED(status));
+  ASSERT_EQ(SIGSTOP, WSTOPSIG(status));
+
+  ASSERT_EQ(0, kill(crasher_pid, SIGCONT)) << strerror(errno);
+
+  AssertDeath(SIGABRT);
+}
+
+TEST_F(CrasherTest, backtrace) {
+  std::string result;
+  int intercept_result;
+  unique_fd output_fd;
+  StartCrasher("abort");
+  StartIntercept(&output_fd);
+
+  std::this_thread::sleep_for(500ms);
+
+  sigval val;
+  val.sival_int = 1;
+  ASSERT_EQ(0, sigqueue(crasher_pid, DEBUGGER_SIGNAL, val)) << strerror(errno);
+  FinishIntercept(&intercept_result);
+  ASSERT_EQ(1, intercept_result) << "tombstoned reported failure";
+  ConsumeFd(std::move(output_fd), &result);
+  ASSERT_MATCH(result, R"(#00 pc [0-9a-f]+  /system/lib)" ARCH_SUFFIX R"(/libc.so \(read\+)");
+
+  int status;
+  ASSERT_EQ(0, waitpid(crasher_pid, &status, WNOHANG | WUNTRACED));
+
+  StartIntercept(&output_fd);
+  FinishCrasher();
+  AssertDeath(SIGABRT);
+  FinishIntercept(&intercept_result);
+  ASSERT_EQ(1, intercept_result) << "tombstoned reported failure";
+  ConsumeFd(std::move(output_fd), &result);
+  ASSERT_MATCH(result, R"(#00 pc [0-9a-f]+\s+ /system/lib)" ARCH_SUFFIX R"(/libc.so \(tgkill)");
+}