Revert "tombstoned: make it easier to add more types of outputs."

Revert "Let crash_dump read /proc/$PID."

Revert submission 1556807-tombstone_proto

Reason for revert: b/178455196, Broken test: android.seccomp.cts.SeccompHostJUnit4DeviceTest#testAppZygoteSyscalls on git_master on cf_x86_64_phone-userdebug

Reverted Changes:
Ide6811297:tombstoned: switch from goto to RAII.
I8d285c4b4:tombstoned: make it easier to add more types of ou...
Id0f0fa285:tombstoned: support for protobuf fds.
I6be6082ab:Let crash_dump read /proc/$PID.
Id812ca390:Make protobuf vendor_ramdisk_available.
Ieeece6e6d:libdebuggerd: add protobuf implementation.

Change-Id: Ib2403c1b61f6cf0513b76361440fbc5909d7554a
diff --git a/debuggerd/debuggerd_test.cpp b/debuggerd/debuggerd_test.cpp
index 191931d..45e555f 100644
--- a/debuggerd/debuggerd_test.cpp
+++ b/debuggerd/debuggerd_test.cpp
@@ -1309,11 +1309,11 @@
   tombstoned_intercept(self, &intercept_fd, &output_fd, &status, kDebuggerdJavaBacktrace);
   ASSERT_EQ(InterceptStatus::kRegistered, status);
 
-  // First connect to tombstoned requesting a native tombstone. This
+  // First connect to tombstoned requesting a native backtrace. This
   // should result in a "regular" FD and not the installed intercept.
   const char native[] = "native";
   unique_fd tombstoned_socket, input_fd;
-  ASSERT_TRUE(tombstoned_connect(self, &tombstoned_socket, &input_fd, kDebuggerdTombstone));
+  ASSERT_TRUE(tombstoned_connect(self, &tombstoned_socket, &input_fd, kDebuggerdNativeBacktrace));
   ASSERT_TRUE(android::base::WriteFully(input_fd.get(), native, sizeof(native)));
   tombstoned_notify_completion(tombstoned_socket.get());
 
diff --git a/debuggerd/tombstoned/tombstoned.cpp b/debuggerd/tombstoned/tombstoned.cpp
index 2b74fd4..57e6b6c 100644
--- a/debuggerd/tombstoned/tombstoned.cpp
+++ b/debuggerd/tombstoned/tombstoned.cpp
@@ -59,26 +59,14 @@
   kCrashStatusQueued,
 };
 
-struct CrashArtifact {
-  unique_fd fd;
-  std::optional<std::string> temporary_path;
-};
-
-struct CrashArtifactPaths {
-  std::string text;
-};
-
-struct CrashOutput {
-  CrashArtifact text;
-};
-
 // Ownership of Crash is a bit messy.
 // It's either owned by an active event that must have a timeout, or owned by
 // queued_requests, in the case that multiple crashes come in at the same time.
 struct Crash {
   ~Crash() { event_free(crash_event); }
 
-  CrashOutput output;
+  std::string crash_tombstone_path;
+  unique_fd crash_tombstone_fd;
   unique_fd crash_socket_fd;
   pid_t crash_pid;
   event* crash_event = nullptr;
@@ -130,56 +118,29 @@
     return &queue;
   }
 
-  CrashArtifact create_temporary_file() const {
-    CrashArtifact result;
-
-    std::optional<std::string> path;
-    result.fd.reset(openat(dir_fd_, ".", O_WRONLY | O_APPEND | O_TMPFILE | O_CLOEXEC, 0640));
-    if (result.fd == -1) {
+  std::pair<std::string, unique_fd> get_output() {
+    std::string path;
+    unique_fd result(openat(dir_fd_, ".", O_WRONLY | O_APPEND | O_TMPFILE | O_CLOEXEC, 0640));
+    if (result == -1) {
       // We might not have O_TMPFILE. Try creating with an arbitrary filename instead.
       static size_t counter = 0;
       std::string tmp_filename = StringPrintf(".temporary%zu", counter++);
-      result.fd.reset(openat(dir_fd_, tmp_filename.c_str(),
-                             O_WRONLY | O_APPEND | O_CREAT | O_TRUNC | O_CLOEXEC, 0640));
-      if (result.fd == -1) {
+      result.reset(openat(dir_fd_, tmp_filename.c_str(),
+                          O_WRONLY | O_APPEND | O_CREAT | O_TRUNC | O_CLOEXEC, 0640));
+      if (result == -1) {
         PLOG(FATAL) << "failed to create temporary tombstone in " << dir_path_;
       }
 
-      result.temporary_path = std::move(tmp_filename);
+      path = StringPrintf("%s/%s", dir_path_.c_str(), tmp_filename.c_str());
     }
-
-    return std::move(result);
+    return std::make_pair(std::move(path), std::move(result));
   }
 
-  std::optional<CrashOutput> get_output(DebuggerdDumpType dump_type) {
-    CrashOutput result;
-
-    switch (dump_type) {
-      case kDebuggerdNativeBacktrace:
-      case kDebuggerdJavaBacktrace:
-        // Don't generate tombstones for backtrace requests.
-        return {};
-
-      case kDebuggerdTombstone:
-        result.text = create_temporary_file();
-        break;
-
-      default:
-        LOG(ERROR) << "unexpected dump type: " << dump_type;
-        return {};
-    }
-
-    return result;
-  }
-
-  borrowed_fd dir_fd() { return dir_fd_; }
-
-  CrashArtifactPaths get_next_artifact_paths() {
-    CrashArtifactPaths result;
-    result.text = StringPrintf("%s%02d", file_name_prefix_.c_str(), next_artifact_);
-
+  std::string get_next_artifact_path() {
+    std::string file_name =
+        StringPrintf("%s/%s%02d", dir_path_.c_str(), file_name_prefix_.c_str(), next_artifact_);
     next_artifact_ = (next_artifact_ + 1) % max_artifacts_;
-    return result;
+    return file_name;
   }
 
   // Consumes crash if it returns true, otherwise leaves it untouched.
@@ -210,8 +171,7 @@
     time_t oldest_time = std::numeric_limits<time_t>::max();
 
     for (size_t i = 0; i < max_artifacts_; ++i) {
-      std::string path =
-          StringPrintf("%s/%s%02zu", dir_path_.c_str(), file_name_prefix_.c_str(), i);
+      std::string path = StringPrintf("%s/%s%02zu", dir_path_.c_str(), file_name_prefix_.c_str(), i);
       struct stat st;
       if (stat(path.c_str(), &st) != 0) {
         if (errno == ENOENT) {
@@ -252,8 +212,7 @@
 static constexpr bool kJavaTraceDumpsEnabled = true;
 
 // Forward declare the callbacks so they can be placed in a sensible order.
-static void crash_accept_cb(evconnlistener* listener, evutil_socket_t sockfd, sockaddr*, int,
-                            void*);
+static void crash_accept_cb(evconnlistener* listener, evutil_socket_t sockfd, sockaddr*, int, void*);
 static void crash_request_cb(evutil_socket_t sockfd, short ev, void* arg);
 static void crash_completed_cb(evutil_socket_t sockfd, short ev, void* arg);
 
@@ -262,20 +221,20 @@
   bool intercepted =
       intercept_manager->GetIntercept(crash->crash_pid, crash->crash_type, &output_fd);
   if (!intercepted) {
-    if (auto o = CrashQueue::for_crash(crash.get())->get_output(crash->crash_type); o) {
-      crash->output = std::move(*o);
-      output_fd.reset(dup(crash->output.text.fd));
+    if (crash->crash_type == kDebuggerdNativeBacktrace) {
+      // Don't generate tombstones for native backtrace requests.
+      output_fd.reset(open("/dev/null", O_WRONLY | O_CLOEXEC));
     } else {
-      LOG(ERROR) << "failed to get crash output for type " << crash->crash_type;
-      return;
+      std::tie(crash->crash_tombstone_path, output_fd) = CrashQueue::for_crash(crash)->get_output();
+      crash->crash_tombstone_fd.reset(dup(output_fd.get()));
     }
   }
 
-  TombstonedCrashPacket response = {.packet_type = CrashPacketType::kPerformDump};
-
+  TombstonedCrashPacket response = {
+    .packet_type = CrashPacketType::kPerformDump
+  };
   ssize_t rc =
       SendFileDescriptors(crash->crash_socket_fd, &response, sizeof(response), output_fd.get());
-
   output_fd.reset();
 
   if (rc == -1) {
@@ -375,20 +334,8 @@
   }
 }
 
-static bool link_fd(borrowed_fd fd, borrowed_fd dirfd, const std::string& path) {
-  std::string fd_path = StringPrintf("/proc/self/fd/%d", fd.get());
-
-  int rc = linkat(AT_FDCWD, fd_path.c_str(), dirfd.get(), path.c_str(), AT_SYMLINK_FOLLOW);
-  if (rc != 0) {
-    PLOG(ERROR) << "failed to link file descriptor";
-    return false;
-  }
-  return true;
-}
-
 static void crash_completed(borrowed_fd sockfd, std::unique_ptr<Crash> crash) {
   TombstonedCrashPacket request = {};
-  CrashQueue* queue = CrashQueue::for_crash(crash);
 
   ssize_t rc = TEMP_FAILURE_RETRY(read(sockfd.get(), &request, sizeof(request)));
   if (rc == -1) {
@@ -406,43 +353,37 @@
     return;
   }
 
-  if (crash->output.text.fd == -1) {
-    LOG(WARNING) << "missing output fd";
-    return;
-  }
+  if (crash->crash_tombstone_fd != -1) {
+    std::string fd_path = StringPrintf("/proc/self/fd/%d", crash->crash_tombstone_fd.get());
+    std::string tombstone_path = CrashQueue::for_crash(crash)->get_next_artifact_path();
 
-  CrashArtifactPaths paths = queue->get_next_artifact_paths();
+    // linkat doesn't let us replace a file, so we need to unlink first.
+    int rc = unlink(tombstone_path.c_str());
+    if (rc != 0 && errno != ENOENT) {
+      PLOG(ERROR) << "failed to unlink tombstone at " << tombstone_path;
+      return;
+    }
 
-  // Always try to unlink the tombstone file.
-  // linkat doesn't let us replace a file, so we need to unlink before linking
-  // our results onto disk, and if we fail for some reason, we should delete
-  // stale tombstones to avoid confusing inconsistency.
-  rc = unlinkat(queue->dir_fd().get(), paths.text.c_str(), 0);
-  if (rc != 0 && errno != ENOENT) {
-    PLOG(ERROR) << "failed to unlink tombstone at " << paths.text;
-    return;
-  }
-
-  if (crash->output.text.fd != -1) {
-    if (!link_fd(crash->output.text.fd, queue->dir_fd(), paths.text)) {
-      LOG(ERROR) << "failed to link tombstone";
+    rc = linkat(AT_FDCWD, fd_path.c_str(), AT_FDCWD, tombstone_path.c_str(), AT_SYMLINK_FOLLOW);
+    if (rc != 0) {
+      PLOG(ERROR) << "failed to link tombstone";
     } else {
       if (crash->crash_type == kDebuggerdJavaBacktrace) {
-        LOG(ERROR) << "Traces for pid " << crash->crash_pid << " written to: " << paths.text;
+        LOG(ERROR) << "Traces for pid " << crash->crash_pid << " written to: " << tombstone_path;
       } else {
         // NOTE: Several tools parse this log message to figure out where the
         // tombstone associated with a given native crash was written. Any changes
         // to this message must be carefully considered.
-        LOG(ERROR) << "Tombstone written to: " << paths.text;
+        LOG(ERROR) << "Tombstone written to: " << tombstone_path;
       }
     }
-  }
 
-  // If we don't have O_TMPFILE, we need to clean up after ourselves.
-  if (crash->output.text.temporary_path) {
-    rc = unlinkat(queue->dir_fd().get(), crash->output.text.temporary_path->c_str(), 0);
-    if (rc != 0) {
-      PLOG(ERROR) << "failed to unlink temporary tombstone at " << paths.text;
+    // If we don't have O_TMPFILE, we need to clean up after ourselves.
+    if (!crash->crash_tombstone_path.empty()) {
+      rc = unlink(crash->crash_tombstone_path.c_str());
+      if (rc != 0) {
+        PLOG(ERROR) << "failed to unlink temporary tombstone at " << crash->crash_tombstone_path;
+      }
     }
   }
 }
@@ -451,7 +392,7 @@
   std::unique_ptr<Crash> crash(static_cast<Crash*>(arg));
   CrashQueue* queue = CrashQueue::for_crash(crash);
 
-  queue->on_crash_completed();
+  CrashQueue::for_crash(crash)->on_crash_completed();
 
   if ((ev & EV_READ) == EV_READ) {
     crash_completed(sockfd, std::move(crash));