Merge "Add fuzz test for libsnapshot"
diff --git a/adb/apex/Android.bp b/adb/apex/Android.bp
index 4346f67..ddb17da 100644
--- a/adb/apex/Android.bp
+++ b/adb/apex/Android.bp
@@ -1,6 +1,7 @@
 apex_defaults {
     name: "com.android.adbd-defaults",
     updatable: true,
+    min_sdk_version: "R",
 
     binaries: ["adbd"],
     compile_multilib: "both",
diff --git a/base/Android.bp b/base/Android.bp
index 894ad6c..61fbc3d 100644
--- a/base/Android.bp
+++ b/base/Android.bp
@@ -51,6 +51,7 @@
         "//apex_available:anyapex",
         "//apex_available:platform",
     ],
+    min_sdk_version: "29",
 }
 
 cc_defaults {
@@ -132,6 +133,7 @@
         "//apex_available:anyapex",
         "//apex_available:platform",
     ],
+    min_sdk_version: "29",
 }
 
 cc_library_static {
@@ -157,6 +159,7 @@
         "errors_test.cpp",
         "expected_test.cpp",
         "file_test.cpp",
+        "logging_splitters_test.cpp",
         "logging_test.cpp",
         "macros_test.cpp",
         "mapped_file_test.cpp",
diff --git a/base/include/android-base/logging.h b/base/include/android-base/logging.h
index accc225..26827fb 100644
--- a/base/include/android-base/logging.h
+++ b/base/include/android-base/logging.h
@@ -118,8 +118,10 @@
 
 void SetDefaultTag(const std::string& tag);
 
-// We expose this even though it is the default because a user that wants to
-// override the default log buffer will have to construct this themselves.
+// The LogdLogger sends chunks of up to ~4000 bytes at a time to logd.  It does not prevent other
+// threads from writing to logd between sending each chunk, so other threads may interleave their
+// messages.  If preventing interleaving is required, then a custom logger that takes a lock before
+// calling this logger should be provided.
 class LogdLogger {
  public:
   explicit LogdLogger(LogId default_log_id = android::base::MAIN);
diff --git a/base/logging.cpp b/base/logging.cpp
index 3c73fea..6e9c67f 100644
--- a/base/logging.cpp
+++ b/base/logging.cpp
@@ -61,6 +61,7 @@
 #include <android-base/threads.h>
 
 #include "liblog_symbols.h"
+#include "logging_splitters.h"
 
 namespace android {
 namespace base {
@@ -190,11 +191,6 @@
   }
 }
 
-static std::mutex& LoggingLock() {
-  static auto& logging_lock = *new std::mutex();
-  return logging_lock;
-}
-
 static LogFunction& Logger() {
 #ifdef __ANDROID__
   static auto& logger = *new LogFunction(LogdLogger());
@@ -239,8 +235,8 @@
 static LogSeverity gMinimumLogSeverity = INFO;
 
 #if defined(__linux__)
-void KernelLogger(android::base::LogId, android::base::LogSeverity severity,
-                  const char* tag, const char*, unsigned int, const char* msg) {
+static void KernelLogLine(const char* msg, int length, android::base::LogSeverity severity,
+                          const char* tag) {
   // clang-format off
   static constexpr int kLogSeverityToKernelLogLevel[] = {
       [android::base::VERBOSE] = 7,              // KERN_DEBUG (there is no verbose kernel log
@@ -265,7 +261,7 @@
   // TODO: should we automatically break up long lines into multiple lines?
   // Or we could log but with something like "..." at the end?
   char buf[1024];
-  size_t size = snprintf(buf, sizeof(buf), "<%d>%s: %s\n", level, tag, msg);
+  size_t size = snprintf(buf, sizeof(buf), "<%d>%s: %.*s\n", level, tag, length, msg);
   if (size > sizeof(buf)) {
     size = snprintf(buf, sizeof(buf), "<%d>%s: %zu-byte message too long for printk\n",
                     level, tag, size);
@@ -276,6 +272,11 @@
   iov[0].iov_len = size;
   TEMP_FAILURE_RETRY(writev(klog_fd, iov, 1));
 }
+
+void KernelLogger(android::base::LogId, android::base::LogSeverity severity, const char* tag,
+                  const char*, unsigned int, const char* full_message) {
+  SplitByLines(full_message, KernelLogLine, severity, tag);
+}
 #endif
 
 void StderrLogger(LogId, LogSeverity severity, const char* tag, const char* file, unsigned int line,
@@ -288,21 +289,10 @@
 #else
   localtime_r(&t, &now);
 #endif
+  auto output_string =
+      StderrOutputGenerator(now, getpid(), GetThreadId(), severity, tag, file, line, message);
 
-  char timestamp[32];
-  strftime(timestamp, sizeof(timestamp), "%m-%d %H:%M:%S", &now);
-
-  static const char log_characters[] = "VDIWEFF";
-  static_assert(arraysize(log_characters) - 1 == FATAL + 1,
-                "Mismatch in size of log_characters and values in LogSeverity");
-  char severity_char = log_characters[severity];
-  if (file != nullptr) {
-    fprintf(stderr, "%s %c %s %5d %5" PRIu64 " %s:%u] %s\n", tag ? tag : "nullptr", severity_char,
-            timestamp, getpid(), GetThreadId(), file, line, message);
-  } else {
-    fprintf(stderr, "%s %c %s %5d %5" PRIu64 " %s\n", tag ? tag : "nullptr", severity_char,
-            timestamp, getpid(), GetThreadId(), message);
-  }
+  fputs(output_string.c_str(), stderr);
 }
 
 void StdioLogger(LogId, LogSeverity severity, const char* /*tag*/, const char* /*file*/,
@@ -324,26 +314,9 @@
   abort();
 }
 
-
-LogdLogger::LogdLogger(LogId default_log_id) : default_log_id_(default_log_id) {
-}
-
-void LogdLogger::operator()(LogId id, LogSeverity severity, const char* tag,
-                            const char* file, unsigned int line,
-                            const char* message) {
-  int32_t priority = LogSeverityToPriority(severity);
-  if (id == DEFAULT) {
-    id = default_log_id_;
-  }
-
+static void LogdLogChunk(LogId id, LogSeverity severity, const char* tag, const char* message) {
   int32_t lg_id = LogIdTolog_id_t(id);
-
-  char log_message_with_file[4068];  // LOGGER_ENTRY_MAX_PAYLOAD, not available in the NDK.
-  if (priority == ANDROID_LOG_FATAL && file != nullptr) {
-    snprintf(log_message_with_file, sizeof(log_message_with_file), "%s:%u] %s", file, line,
-             message);
-    message = log_message_with_file;
-  }
+  int32_t priority = LogSeverityToPriority(severity);
 
   static auto& liblog_functions = GetLibLogFunctions();
   if (liblog_functions) {
@@ -355,6 +328,17 @@
   }
 }
 
+LogdLogger::LogdLogger(LogId default_log_id) : default_log_id_(default_log_id) {}
+
+void LogdLogger::operator()(LogId id, LogSeverity severity, const char* tag, const char* file,
+                            unsigned int line, const char* message) {
+  if (id == DEFAULT) {
+    id = default_log_id_;
+  }
+
+  SplitByLogdChunks(id, severity, tag, file, line, message, LogdLogChunk);
+}
+
 void InitLogging(char* argv[], LogFunction&& logger, AbortFunction&& aborter) {
   SetLogger(std::forward<LogFunction>(logger));
   SetAborter(std::forward<AbortFunction>(aborter));
@@ -515,26 +499,8 @@
 #endif
   }
 
-  {
-    // Do the actual logging with the lock held.
-    std::lock_guard<std::mutex> lock(LoggingLock());
-    if (msg.find('\n') == std::string::npos) {
-      LogLine(data_->GetFile(), data_->GetLineNumber(), data_->GetSeverity(), data_->GetTag(),
-              msg.c_str());
-    } else {
-      msg += '\n';
-      size_t i = 0;
-      while (i < msg.size()) {
-        size_t nl = msg.find('\n', i);
-        msg[nl] = '\0';
-        LogLine(data_->GetFile(), data_->GetLineNumber(), data_->GetSeverity(), data_->GetTag(),
-                &msg[i]);
-        // Undo the zero-termination so we can give the complete message to the aborter.
-        msg[nl] = '\n';
-        i = nl + 1;
-      }
-    }
-  }
+  LogLine(data_->GetFile(), data_->GetLineNumber(), data_->GetSeverity(), data_->GetTag(),
+          msg.c_str());
 
   // Abort if necessary.
   if (data_->GetSeverity() == FATAL) {
diff --git a/base/logging_splitters.h b/base/logging_splitters.h
new file mode 100644
index 0000000..2ec2b20
--- /dev/null
+++ b/base/logging_splitters.h
@@ -0,0 +1,185 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+
+#pragma once
+
+#include <inttypes.h>
+
+#include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+
+#define LOGGER_ENTRY_MAX_PAYLOAD 4068  // This constant is not in the NDK.
+
+namespace android {
+namespace base {
+
+// This splits the message up line by line, by calling log_function with a pointer to the start of
+// each line and the size up to the newline character.  It sends size = -1 for the final line.
+template <typename F, typename... Args>
+static void SplitByLines(const char* msg, const F& log_function, Args&&... args) {
+  const char* newline = strchr(msg, '\n');
+  while (newline != nullptr) {
+    log_function(msg, newline - msg, args...);
+    msg = newline + 1;
+    newline = strchr(msg, '\n');
+  }
+
+  log_function(msg, -1, args...);
+}
+
+// This splits the message up into chunks that logs can process delimited by new lines.  It calls
+// log_function with the exact null terminated message that should be sent to logd.
+// Note, despite the loops and snprintf's, if severity is not fatal and there are no new lines,
+// this function simply calls log_function with msg without any extra overhead.
+template <typename F>
+static void SplitByLogdChunks(LogId log_id, LogSeverity severity, const char* tag, const char* file,
+                              unsigned int line, const char* msg, const F& log_function) {
+  // The maximum size of a payload, after the log header that logd will accept is
+  // LOGGER_ENTRY_MAX_PAYLOAD, so subtract the other elements in the payload to find the size of
+  // the string that we can log in each pass.
+  // The protocol is documented in liblog/README.protocol.md.
+  // Specifically we subtract a byte for the priority, the length of the tag + its null terminator,
+  // and an additional byte for the null terminator on the payload.  We subtract an additional 32
+  // bytes for slack, similar to java/android/util/Log.java.
+  ptrdiff_t max_size = LOGGER_ENTRY_MAX_PAYLOAD - strlen(tag) - 35;
+  if (max_size <= 0) {
+    abort();
+  }
+  // If we're logging a fatal message, we'll append the file and line numbers.
+  bool add_file = file != nullptr && (severity == FATAL || severity == FATAL_WITHOUT_ABORT);
+
+  std::string file_header;
+  if (add_file) {
+    file_header = StringPrintf("%s:%u] ", file, line);
+  }
+  int file_header_size = file_header.size();
+
+  __attribute__((uninitialized)) char logd_chunk[max_size + 1];
+  ptrdiff_t chunk_position = 0;
+
+  auto call_log_function = [&]() {
+    log_function(log_id, severity, tag, logd_chunk);
+    chunk_position = 0;
+  };
+
+  auto write_to_logd_chunk = [&](const char* message, int length) {
+    int size_written = 0;
+    const char* new_line = chunk_position > 0 ? "\n" : "";
+    if (add_file) {
+      size_written = snprintf(logd_chunk + chunk_position, sizeof(logd_chunk) - chunk_position,
+                              "%s%s%.*s", new_line, file_header.c_str(), length, message);
+    } else {
+      size_written = snprintf(logd_chunk + chunk_position, sizeof(logd_chunk) - chunk_position,
+                              "%s%.*s", new_line, length, message);
+    }
+
+    // This should never fail, if it does and we set size_written to 0, which will skip this line
+    // and move to the next one.
+    if (size_written < 0) {
+      size_written = 0;
+    }
+    chunk_position += size_written;
+  };
+
+  const char* newline = strchr(msg, '\n');
+  while (newline != nullptr) {
+    // If we have data in the buffer and this next line doesn't fit, write the buffer.
+    if (chunk_position != 0 && chunk_position + (newline - msg) + 1 + file_header_size > max_size) {
+      call_log_function();
+    }
+
+    // Otherwise, either the next line fits or we have any empty buffer and too large of a line to
+    // ever fit, in both cases, we add it to the buffer and continue.
+    write_to_logd_chunk(msg, newline - msg);
+
+    msg = newline + 1;
+    newline = strchr(msg, '\n');
+  }
+
+  // If we have left over data in the buffer and we can fit the rest of msg, add it to the buffer
+  // then write the buffer.
+  if (chunk_position != 0 &&
+      chunk_position + static_cast<int>(strlen(msg)) + 1 + file_header_size <= max_size) {
+    write_to_logd_chunk(msg, -1);
+    call_log_function();
+  } else {
+    // If the buffer is not empty and we can't fit the rest of msg into it, write its contents.
+    if (chunk_position != 0) {
+      call_log_function();
+    }
+    // Then write the rest of the msg.
+    if (add_file) {
+      snprintf(logd_chunk, sizeof(logd_chunk), "%s%s", file_header.c_str(), msg);
+      log_function(log_id, severity, tag, logd_chunk);
+    } else {
+      log_function(log_id, severity, tag, msg);
+    }
+  }
+}
+
+static std::pair<int, int> CountSizeAndNewLines(const char* message) {
+  int size = 0;
+  int new_lines = 0;
+  while (*message != '\0') {
+    size++;
+    if (*message == '\n') {
+      ++new_lines;
+    }
+    ++message;
+  }
+  return {size, new_lines};
+}
+
+// This adds the log header to each line of message and returns it as a string intended to be
+// written to stderr.
+static std::string StderrOutputGenerator(const struct tm& now, int pid, uint64_t tid,
+                                         LogSeverity severity, const char* tag, const char* file,
+                                         unsigned int line, const char* message) {
+  char timestamp[32];
+  strftime(timestamp, sizeof(timestamp), "%m-%d %H:%M:%S", &now);
+
+  static const char log_characters[] = "VDIWEFF";
+  static_assert(arraysize(log_characters) - 1 == FATAL + 1,
+                "Mismatch in size of log_characters and values in LogSeverity");
+  char severity_char = log_characters[severity];
+  std::string line_prefix;
+  if (file != nullptr) {
+    line_prefix = StringPrintf("%s %c %s %5d %5" PRIu64 " %s:%u] ", tag ? tag : "nullptr",
+                               severity_char, timestamp, pid, tid, file, line);
+  } else {
+    line_prefix = StringPrintf("%s %c %s %5d %5" PRIu64 " ", tag ? tag : "nullptr", severity_char,
+                               timestamp, pid, tid);
+  }
+
+  auto [size, new_lines] = CountSizeAndNewLines(message);
+  std::string output_string;
+  output_string.reserve(size + new_lines * line_prefix.size() + 1);
+
+  auto concat_lines = [&](const char* message, int size) {
+    output_string.append(line_prefix);
+    if (size == -1) {
+      output_string.append(message);
+    } else {
+      output_string.append(message, size);
+    }
+    output_string.append("\n");
+  };
+  SplitByLines(message, concat_lines);
+  return output_string;
+}
+
+}  // namespace base
+}  // namespace android
diff --git a/base/logging_splitters_test.cpp b/base/logging_splitters_test.cpp
new file mode 100644
index 0000000..679d19e
--- /dev/null
+++ b/base/logging_splitters_test.cpp
@@ -0,0 +1,325 @@
+/*
+ * Copyright (C) 2020 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 "logging_splitters.h"
+
+#include <string>
+#include <vector>
+
+#include <android-base/strings.h>
+#include <gtest/gtest.h>
+
+namespace android {
+namespace base {
+
+void TestNewlineSplitter(const std::string& input,
+                         const std::vector<std::string>& expected_output) {
+  std::vector<std::string> output;
+  auto logger_function = [&](const char* msg, int length) {
+    if (length == -1) {
+      output.push_back(msg);
+    } else {
+      output.push_back(std::string(msg, length));
+    }
+  };
+  SplitByLines(input.c_str(), logger_function);
+
+  EXPECT_EQ(expected_output, output);
+}
+
+TEST(logging_splitters, NewlineSplitter_EmptyString) {
+  TestNewlineSplitter("", std::vector<std::string>{""});
+}
+
+TEST(logging_splitters, NewlineSplitter_BasicString) {
+  TestNewlineSplitter("normal string", std::vector<std::string>{"normal string"});
+}
+
+TEST(logging_splitters, NewlineSplitter_ormalBasicStringTrailingNewline) {
+  TestNewlineSplitter("normal string\n", std::vector<std::string>{"normal string", ""});
+}
+
+TEST(logging_splitters, NewlineSplitter_MultilineTrailing) {
+  TestNewlineSplitter("normal string\nsecond string\nthirdstring",
+                      std::vector<std::string>{"normal string", "second string", "thirdstring"});
+}
+
+TEST(logging_splitters, NewlineSplitter_MultilineTrailingNewline) {
+  TestNewlineSplitter(
+      "normal string\nsecond string\nthirdstring\n",
+      std::vector<std::string>{"normal string", "second string", "thirdstring", ""});
+}
+
+TEST(logging_splitters, NewlineSplitter_MultilineEmbeddedNewlines) {
+  TestNewlineSplitter(
+      "normal string\n\n\nsecond string\n\nthirdstring\n",
+      std::vector<std::string>{"normal string", "", "", "second string", "", "thirdstring", ""});
+}
+
+void TestLogdChunkSplitter(const std::string& tag, const std::string& file,
+                           const std::string& input,
+                           const std::vector<std::string>& expected_output) {
+  std::vector<std::string> output;
+  auto logger_function = [&](LogId, LogSeverity, const char*, const char* msg) {
+    output.push_back(msg);
+  };
+
+  SplitByLogdChunks(MAIN, FATAL, tag.c_str(), file.empty() ? nullptr : file.c_str(), 1000,
+                    input.c_str(), logger_function);
+
+  auto return_lengths = [&] {
+    std::string sizes;
+    sizes += "expected_output sizes:";
+    for (const auto& string : expected_output) {
+      sizes += " " + std::to_string(string.size());
+    }
+    sizes += "\noutput sizes:";
+    for (const auto& string : output) {
+      sizes += " " + std::to_string(string.size());
+    }
+    return sizes;
+  };
+
+  EXPECT_EQ(expected_output, output) << return_lengths();
+}
+
+TEST(logging_splitters, LogdChunkSplitter_EmptyString) {
+  TestLogdChunkSplitter("tag", "", "", std::vector<std::string>{""});
+}
+
+TEST(logging_splitters, LogdChunkSplitter_BasicString) {
+  TestLogdChunkSplitter("tag", "", "normal string", std::vector<std::string>{"normal string"});
+}
+
+TEST(logging_splitters, LogdChunkSplitter_NormalBasicStringTrailingNewline) {
+  TestLogdChunkSplitter("tag", "", "normal string\n", std::vector<std::string>{"normal string\n"});
+}
+
+TEST(logging_splitters, LogdChunkSplitter_MultilineTrailing) {
+  TestLogdChunkSplitter("tag", "", "normal string\nsecond string\nthirdstring",
+                        std::vector<std::string>{"normal string\nsecond string\nthirdstring"});
+}
+
+TEST(logging_splitters, LogdChunkSplitter_MultilineTrailingNewline) {
+  TestLogdChunkSplitter("tag", "", "normal string\nsecond string\nthirdstring\n",
+                        std::vector<std::string>{"normal string\nsecond string\nthirdstring\n"});
+}
+
+TEST(logging_splitters, LogdChunkSplitter_MultilineEmbeddedNewlines) {
+  TestLogdChunkSplitter(
+      "tag", "", "normal string\n\n\nsecond string\n\nthirdstring\n",
+      std::vector<std::string>{"normal string\n\n\nsecond string\n\nthirdstring\n"});
+}
+
+// This test should return the same string, the logd logger itself will truncate down to size.
+// This has historically been the behavior both in libbase and liblog.
+TEST(logging_splitters, LogdChunkSplitter_HugeLineNoNewline) {
+  auto long_string = std::string(LOGGER_ENTRY_MAX_PAYLOAD, 'x');
+  ASSERT_EQ(LOGGER_ENTRY_MAX_PAYLOAD, static_cast<int>(long_string.size()));
+
+  TestLogdChunkSplitter("tag", "", long_string, std::vector{long_string});
+}
+
+std::string ReduceToMaxSize(const std::string& tag, const std::string& string) {
+  return string.substr(0, LOGGER_ENTRY_MAX_PAYLOAD - tag.size() - 35);
+}
+
+TEST(logging_splitters, LogdChunkSplitter_MultipleHugeLineNoNewline) {
+  auto long_string_x = std::string(LOGGER_ENTRY_MAX_PAYLOAD, 'x');
+  auto long_string_y = std::string(LOGGER_ENTRY_MAX_PAYLOAD, 'y');
+  auto long_string_z = std::string(LOGGER_ENTRY_MAX_PAYLOAD, 'z');
+
+  auto long_strings = long_string_x + '\n' + long_string_y + '\n' + long_string_z;
+
+  std::string tag = "tag";
+  std::vector expected = {ReduceToMaxSize(tag, long_string_x), ReduceToMaxSize(tag, long_string_y),
+                          long_string_z};
+
+  TestLogdChunkSplitter(tag, "", long_strings, expected);
+}
+
+// With a ~4k buffer, we should print 2 long strings per logger call.
+TEST(logging_splitters, LogdChunkSplitter_Multiple2kLines) {
+  std::vector expected = {
+      std::string(2000, 'a') + '\n' + std::string(2000, 'b'),
+      std::string(2000, 'c') + '\n' + std::string(2000, 'd'),
+      std::string(2000, 'e') + '\n' + std::string(2000, 'f'),
+  };
+
+  auto long_strings = Join(expected, '\n');
+
+  TestLogdChunkSplitter("tag", "", long_strings, expected);
+}
+
+TEST(logging_splitters, LogdChunkSplitter_ExactSizedLines) {
+  const char* tag = "tag";
+  ptrdiff_t max_size = LOGGER_ENTRY_MAX_PAYLOAD - strlen(tag) - 35;
+  auto long_string_a = std::string(max_size, 'a');
+  auto long_string_b = std::string(max_size, 'b');
+  auto long_string_c = std::string(max_size, 'c');
+
+  auto long_strings = long_string_a + '\n' + long_string_b + '\n' + long_string_c;
+
+  TestLogdChunkSplitter(tag, "", long_strings,
+                        std::vector{long_string_a, long_string_b, long_string_c});
+}
+
+TEST(logging_splitters, LogdChunkSplitter_UnderEqualOver) {
+  std::string tag = "tag";
+  ptrdiff_t max_size = LOGGER_ENTRY_MAX_PAYLOAD - tag.size() - 35;
+
+  auto first_string_size = 1000;
+  auto first_string = std::string(first_string_size, 'a');
+  auto second_string_size = max_size - first_string_size - 1;
+  auto second_string = std::string(second_string_size, 'b');
+
+  auto exact_string = std::string(max_size, 'c');
+
+  auto large_string = std::string(max_size + 50, 'd');
+
+  auto final_string = std::string("final string!\n\nfinal \n \n final \n");
+
+  std::vector expected = {first_string + '\n' + second_string, exact_string,
+                          ReduceToMaxSize(tag, large_string), final_string};
+
+  std::vector input_strings = {first_string + '\n' + second_string, exact_string, large_string,
+                               final_string};
+  auto long_strings = Join(input_strings, '\n');
+
+  TestLogdChunkSplitter(tag, "", long_strings, expected);
+}
+
+TEST(logging_splitters, LogdChunkSplitter_WithFile) {
+  std::string tag = "tag";
+  std::string file = "/path/to/myfile.cpp";
+  int line = 1000;
+  auto file_header = StringPrintf("%s:%d] ", file.c_str(), line);
+  ptrdiff_t max_size = LOGGER_ENTRY_MAX_PAYLOAD - tag.size() - 35;
+
+  auto first_string_size = 1000;
+  auto first_string = std::string(first_string_size, 'a');
+  auto second_string_size = max_size - first_string_size - 1 - 2 * file_header.size();
+  auto second_string = std::string(second_string_size, 'b');
+
+  auto exact_string = std::string(max_size - file_header.size(), 'c');
+
+  auto large_string = std::string(max_size + 50, 'd');
+
+  auto final_string = std::string("final string!");
+
+  std::vector expected = {
+      file_header + first_string + '\n' + file_header + second_string, file_header + exact_string,
+      file_header + ReduceToMaxSize(file_header + tag, large_string), file_header + final_string};
+
+  std::vector input_strings = {first_string + '\n' + second_string, exact_string, large_string,
+                               final_string};
+  auto long_strings = Join(input_strings, '\n');
+
+  TestLogdChunkSplitter(tag, file, long_strings, expected);
+}
+
+// We set max_size based off of tag, so if it's too large, the buffer will be sized wrong.
+// We could recover from this, but it's certainly an error for someone to attempt to use a tag this
+// large, so we abort instead.
+TEST(logging_splitters, LogdChunkSplitter_TooLongTag) {
+  auto long_tag = std::string(5000, 'x');
+  auto logger_function = [](LogId, LogSeverity, const char*, const char*) {};
+  ASSERT_DEATH(
+      SplitByLogdChunks(MAIN, ERROR, long_tag.c_str(), nullptr, 0, "message", logger_function), "");
+}
+
+// We do handle excessively large file names correctly however.
+TEST(logging_splitters, LogdChunkSplitter_TooLongFile) {
+  auto long_file = std::string(5000, 'x');
+  std::string tag = "tag";
+
+  std::vector expected = {ReduceToMaxSize(tag, long_file), ReduceToMaxSize(tag, long_file)};
+
+  TestLogdChunkSplitter(tag, long_file, "can't see me\nor me", expected);
+}
+
+void TestStderrOutputGenerator(const char* tag, const char* file, int line, const char* message,
+                               const std::string& expected) {
+  // All log messages will show "01-01 00:00:00"
+  struct tm now = {
+      .tm_sec = 0,
+      .tm_min = 0,
+      .tm_hour = 0,
+      .tm_mday = 1,
+      .tm_mon = 0,
+      .tm_year = 1970,
+  };
+
+  int pid = 1234;       // All log messages will have 1234 for their PID.
+  uint64_t tid = 4321;  // All log messages will have 4321 for their TID.
+
+  auto result = StderrOutputGenerator(now, pid, tid, ERROR, tag, file, line, message);
+  EXPECT_EQ(expected, result);
+}
+
+TEST(logging_splitters, StderrOutputGenerator_Basic) {
+  TestStderrOutputGenerator(nullptr, nullptr, 0, "simple message",
+                            "nullptr E 01-01 00:00:00  1234  4321 simple message\n");
+  TestStderrOutputGenerator("tag", nullptr, 0, "simple message",
+                            "tag E 01-01 00:00:00  1234  4321 simple message\n");
+  TestStderrOutputGenerator(
+      "tag", "/path/to/some/file", 0, "simple message",
+      "tag E 01-01 00:00:00  1234  4321 /path/to/some/file:0] simple message\n");
+}
+
+TEST(logging_splitters, StderrOutputGenerator_NewlineTagAndFile) {
+  TestStderrOutputGenerator("tag\n\n", nullptr, 0, "simple message",
+                            "tag\n\n E 01-01 00:00:00  1234  4321 simple message\n");
+  TestStderrOutputGenerator(
+      "tag", "/path/to/some/file\n\n", 0, "simple message",
+      "tag E 01-01 00:00:00  1234  4321 /path/to/some/file\n\n:0] simple message\n");
+}
+
+TEST(logging_splitters, StderrOutputGenerator_TrailingNewLine) {
+  TestStderrOutputGenerator(
+      "tag", nullptr, 0, "simple message\n",
+      "tag E 01-01 00:00:00  1234  4321 simple message\ntag E 01-01 00:00:00  1234  4321 \n");
+}
+
+TEST(logging_splitters, StderrOutputGenerator_MultiLine) {
+  const char* expected_result =
+      "tag E 01-01 00:00:00  1234  4321 simple message\n"
+      "tag E 01-01 00:00:00  1234  4321 \n"
+      "tag E 01-01 00:00:00  1234  4321 \n"
+      "tag E 01-01 00:00:00  1234  4321 another message \n"
+      "tag E 01-01 00:00:00  1234  4321 \n"
+      "tag E 01-01 00:00:00  1234  4321  final message \n"
+      "tag E 01-01 00:00:00  1234  4321 \n"
+      "tag E 01-01 00:00:00  1234  4321 \n"
+      "tag E 01-01 00:00:00  1234  4321 \n";
+
+  TestStderrOutputGenerator("tag", nullptr, 0,
+                            "simple message\n\n\nanother message \n\n final message \n\n\n",
+                            expected_result);
+}
+
+TEST(logging_splitters, StderrOutputGenerator_MultiLineLong) {
+  auto long_string_a = std::string(4000, 'a');
+  auto long_string_b = std::string(4000, 'b');
+
+  auto message = long_string_a + '\n' + long_string_b;
+  auto expected_result = "tag E 01-01 00:00:00  1234  4321 " + long_string_a + '\n' +
+                         "tag E 01-01 00:00:00  1234  4321 " + long_string_b + '\n';
+  TestStderrOutputGenerator("tag", nullptr, 0, message.c_str(), expected_result);
+}
+
+}  // namespace base
+}  // namespace android
diff --git a/base/logging_test.cpp b/base/logging_test.cpp
index 3a453e6..593e2c1 100644
--- a/base/logging_test.cpp
+++ b/base/logging_test.cpp
@@ -24,8 +24,10 @@
 
 #include <regex>
 #include <string>
+#include <thread>
 
 #include "android-base/file.h"
+#include "android-base/scopeguard.h"
 #include "android-base/stringprintf.h"
 #include "android-base/test_utils.h"
 
@@ -596,7 +598,7 @@
   CapturedStderr cap;
   LOG(FATAL) << "foo\nbar";
 
-  EXPECT_EQ(CountLineAborter::newline_count, 1U + 1U);  // +1 for final '\n'.
+  EXPECT_EQ(CountLineAborter::newline_count, 1U);
 }
 
 __attribute__((constructor)) void TestLoggingInConstructor() {
@@ -617,3 +619,55 @@
   // Whereas ERROR logging includes the program name.
   ASSERT_EQ(android::base::Basename(android::base::GetExecutablePath()) + ": err\n", cap_err.str());
 }
+
+TEST(logging, ForkSafe) {
+#if !defined(_WIN32)
+  using namespace android::base;
+  SetLogger(
+      [&](LogId, LogSeverity, const char*, const char*, unsigned int, const char*) { sleep(3); });
+
+  auto guard = make_scope_guard([&] {
+#ifdef __ANDROID__
+    SetLogger(LogdLogger());
+#else
+    SetLogger(StderrLogger);
+#endif
+  });
+
+  auto thread = std::thread([] {
+    LOG(ERROR) << "This should sleep for 3 seconds, long enough to fork another process, if there "
+                  "is no intervention";
+  });
+  thread.detach();
+
+  auto pid = fork();
+  ASSERT_NE(-1, pid);
+
+  if (pid == 0) {
+    // Reset the logger, so the next message doesn't sleep().
+    SetLogger([](LogId, LogSeverity, const char*, const char*, unsigned int, const char*) {});
+    LOG(ERROR) << "This should succeed in the child, only if libbase is forksafe.";
+    _exit(EXIT_SUCCESS);
+  }
+
+  // Wait for up to 3 seconds for the child to exit.
+  int tries = 3;
+  bool found_child = false;
+  while (tries-- > 0) {
+    auto result = waitpid(pid, nullptr, WNOHANG);
+    EXPECT_NE(-1, result);
+    if (result == pid) {
+      found_child = true;
+      break;
+    }
+    sleep(1);
+  }
+
+  EXPECT_TRUE(found_child);
+
+  // Kill the child if it did not exit.
+  if (!found_child) {
+    kill(pid, SIGKILL);
+  }
+#endif
+}
diff --git a/fs_mgr/README.overlayfs.md b/fs_mgr/README.overlayfs.md
index f579078..ca782b9 100644
--- a/fs_mgr/README.overlayfs.md
+++ b/fs_mgr/README.overlayfs.md
@@ -42,7 +42,7 @@
     $ adb push <source> <destination>
     $ adb reboot
 
-Note that you can replace these two lines:
+Note that you can replace these two lines in the above sequence:
 
     $ adb disable-verity
     $ adb reboot
@@ -51,7 +51,7 @@
 
     $ adb remount -R
 
-**Note:** _adb reboot -R_ won’t reboot if the device is already in the adb remount state.
+**Note:** _adb remount -R_ won’t reboot if the device is already in the adb remount state.
 
 None of this changes if OverlayFS needs to be engaged.
 The decisions whether to use traditional direct file-system remount,
diff --git a/fs_mgr/liblp/builder.cpp b/fs_mgr/liblp/builder.cpp
index 2f516fa..dc3b985 100644
--- a/fs_mgr/liblp/builder.cpp
+++ b/fs_mgr/liblp/builder.cpp
@@ -401,8 +401,8 @@
         // untouched to be compatible code that looks for an MBR. Thus we
         // start counting free sectors at sector 1, not 0.
         uint64_t free_area_start = LP_SECTOR_SIZE;
-        if (out.alignment || out.alignment_offset) {
-            free_area_start = AlignTo(free_area_start, out.alignment, out.alignment_offset);
+        if (out.alignment) {
+            free_area_start = AlignTo(free_area_start, out.alignment);
         } else {
             free_area_start = AlignTo(free_area_start, logical_block_size);
         }
@@ -442,7 +442,7 @@
     // Compute the first free sector, factoring in alignment.
     uint64_t free_area_start = total_reserved;
     if (super.alignment || super.alignment_offset) {
-        free_area_start = AlignTo(free_area_start, super.alignment, super.alignment_offset);
+        free_area_start = AlignTo(free_area_start, super.alignment);
     } else {
         free_area_start = AlignTo(free_area_start, logical_block_size);
     }
@@ -930,7 +930,7 @@
     // Note: when reading alignment info from the Kernel, we don't assume it
     // is aligned to the sector size, so we round up to the nearest sector.
     uint64_t lba = sector * LP_SECTOR_SIZE;
-    uint64_t aligned = AlignTo(lba, block_device.alignment, block_device.alignment_offset);
+    uint64_t aligned = AlignTo(lba, block_device.alignment);
     return AlignTo(aligned, LP_SECTOR_SIZE) / LP_SECTOR_SIZE;
 }
 
diff --git a/fs_mgr/liblp/builder_test.cpp b/fs_mgr/liblp/builder_test.cpp
index 977ebe3..52a3217 100644
--- a/fs_mgr/liblp/builder_test.cpp
+++ b/fs_mgr/liblp/builder_test.cpp
@@ -174,7 +174,7 @@
     ASSERT_NE(exported, nullptr);
     super_device = GetMetadataSuperBlockDevice(*exported.get());
     ASSERT_NE(super_device, nullptr);
-    EXPECT_EQ(super_device->first_logical_sector, 1472);
+    EXPECT_EQ(super_device->first_logical_sector, 1536);
 
     // Alignment offset without alignment doesn't mean anything.
     device_info.alignment = 0;
@@ -190,7 +190,7 @@
     ASSERT_NE(exported, nullptr);
     super_device = GetMetadataSuperBlockDevice(*exported.get());
     ASSERT_NE(super_device, nullptr);
-    EXPECT_EQ(super_device->first_logical_sector, 174);
+    EXPECT_EQ(super_device->first_logical_sector, 168);
 
     // Test a small alignment with no alignment offset.
     device_info.alignment = 11 * 1024;
@@ -200,7 +200,7 @@
     ASSERT_NE(exported, nullptr);
     super_device = GetMetadataSuperBlockDevice(*exported.get());
     ASSERT_NE(super_device, nullptr);
-    EXPECT_EQ(super_device->first_logical_sector, 160);
+    EXPECT_EQ(super_device->first_logical_sector, 154);
 }
 
 TEST_F(BuilderTest, InternalPartitionAlignment) {
@@ -229,12 +229,12 @@
         EXPECT_EQ(extent.num_sectors, 80);
 
         uint64_t lba = extent.target_data * LP_SECTOR_SIZE;
-        uint64_t aligned_lba = AlignTo(lba, device_info.alignment, device_info.alignment_offset);
+        uint64_t aligned_lba = AlignTo(lba, device_info.alignment);
         EXPECT_EQ(lba, aligned_lba);
     }
 
     // Sanity check one extent.
-    EXPECT_EQ(exported->extents.back().target_data, 3008);
+    EXPECT_EQ(exported->extents.back().target_data, 3072);
 }
 
 TEST_F(BuilderTest, UseAllDiskSpace) {
@@ -652,7 +652,7 @@
     };
     unique_ptr<MetadataBuilder> builder = MetadataBuilder::New(partitions, "system_a", 65536, 2);
     ASSERT_NE(builder, nullptr);
-    EXPECT_EQ(builder->AllocatableSpace(), 467238912);
+    EXPECT_EQ(builder->AllocatableSpace(), 467402752);
 
     // Create a partition that spans 3 devices.
     Partition* p = builder->AddPartition("system_a", 0);
@@ -675,17 +675,17 @@
     EXPECT_EQ(metadata->block_devices[2].alignment, 786432);
     EXPECT_EQ(metadata->block_devices[2].alignment_offset, 753664);
     ASSERT_EQ(metadata->extents.size(), 3);
-    EXPECT_EQ(metadata->extents[0].num_sectors, 522304);
+    EXPECT_EQ(metadata->extents[0].num_sectors, 522752);
     EXPECT_EQ(metadata->extents[0].target_type, LP_TARGET_TYPE_LINEAR);
-    EXPECT_EQ(metadata->extents[0].target_data, 1984);
+    EXPECT_EQ(metadata->extents[0].target_data, 1536);
     EXPECT_EQ(metadata->extents[0].target_source, 0);
-    EXPECT_EQ(metadata->extents[1].num_sectors, 260672);
+    EXPECT_EQ(metadata->extents[1].num_sectors, 260608);
     EXPECT_EQ(metadata->extents[1].target_type, LP_TARGET_TYPE_LINEAR);
-    EXPECT_EQ(metadata->extents[1].target_data, 1472);
+    EXPECT_EQ(metadata->extents[1].target_data, 1536);
     EXPECT_EQ(metadata->extents[1].target_source, 1);
-    EXPECT_EQ(metadata->extents[2].num_sectors, 129088);
+    EXPECT_EQ(metadata->extents[2].num_sectors, 128704);
     EXPECT_EQ(metadata->extents[2].target_type, LP_TARGET_TYPE_LINEAR);
-    EXPECT_EQ(metadata->extents[2].target_data, 1472);
+    EXPECT_EQ(metadata->extents[2].target_data, 1536);
     EXPECT_EQ(metadata->extents[2].target_source, 2);
 }
 
@@ -1019,3 +1019,35 @@
     EXPECT_FALSE(extent.OverlapsWith(LinearExtent{20, 1, 15}));
     EXPECT_FALSE(extent.OverlapsWith(LinearExtent{20, 1, 10}));
 }
+
+TEST_F(BuilderTest, AlignFreeRegion) {
+    BlockDeviceInfo super("super", 8_GiB, 786432, 0, 4096);
+    std::vector<BlockDeviceInfo> block_devices = {super};
+
+    unique_ptr<MetadataBuilder> builder = MetadataBuilder::New(block_devices, "super", 65536, 2);
+    ASSERT_NE(builder, nullptr);
+
+    Partition* p = builder->AddPartition("system", "default", 0);
+    ASSERT_NE(p, nullptr);
+    ASSERT_TRUE(builder->AddLinearExtent(p, "super", 64, (super.alignment + 4096) / 512));
+
+    p = builder->AddPartition("vendor", "default", 0);
+    ASSERT_NE(p, nullptr);
+    ASSERT_TRUE(builder->ResizePartition(p, 2_GiB));
+
+    const auto& extents = p->extents();
+    ASSERT_EQ(extents.size(), 2);
+
+    LinearExtent* e1 = extents[0]->AsLinearExtent();
+    ASSERT_NE(e1, nullptr);
+    LinearExtent* e2 = extents[1]->AsLinearExtent();
+    ASSERT_NE(e2, nullptr);
+
+    // The misaligned partition starting at sector 1544 should not cause any
+    // overlap with previous extents. We should see vendor punch a hole where
+    // "system" is, extending the hole up to the next aligned block.
+    EXPECT_EQ(e1->physical_sector(), 1536);
+    EXPECT_EQ(e1->end_sector(), 1544);
+    EXPECT_EQ(e2->physical_sector(), 3072);
+    EXPECT_EQ(e2->end_sector(), 4197368);
+}
diff --git a/fs_mgr/liblp/device_test.cpp b/fs_mgr/liblp/device_test.cpp
index 99bff6e..6af9d94 100644
--- a/fs_mgr/liblp/device_test.cpp
+++ b/fs_mgr/liblp/device_test.cpp
@@ -50,16 +50,7 @@
     // Sanity check that the device doesn't give us some weird inefficient
     // alignment.
     EXPECT_EQ(device_info.alignment % LP_SECTOR_SIZE, 0);
-    EXPECT_EQ(device_info.alignment_offset % LP_SECTOR_SIZE, 0);
-    EXPECT_LE(device_info.alignment_offset, INT_MAX);
     EXPECT_EQ(device_info.logical_block_size % LP_SECTOR_SIZE, 0);
-
-    // Having an alignment offset > alignment doesn't really make sense.
-    EXPECT_LT(device_info.alignment_offset, device_info.alignment);
-
-    if (IPropertyFetcher::GetInstance()->GetBoolProperty("ro.virtual_ab.enabled", false)) {
-        EXPECT_EQ(device_info.alignment_offset, 0);
-    }
 }
 
 TEST_F(DeviceTest, ReadSuperPartitionCurrentSlot) {
diff --git a/fs_mgr/liblp/utility.h b/fs_mgr/liblp/utility.h
index 0661769..f210eaf 100644
--- a/fs_mgr/liblp/utility.h
+++ b/fs_mgr/liblp/utility.h
@@ -78,17 +78,6 @@
     return base + (alignment - remainder);
 }
 
-// Same as the above |AlignTo|, except that |base| is only aligned when added to
-// |alignment_offset|.
-constexpr uint64_t AlignTo(uint64_t base, uint32_t alignment, uint32_t alignment_offset) {
-    uint64_t aligned = AlignTo(base, alignment) + alignment_offset;
-    if (aligned - alignment >= base) {
-        // We overaligned (base < alignment_offset).
-        return aligned - alignment;
-    }
-    return aligned;
-}
-
 // Update names from C++ strings.
 bool UpdateBlockDevicePartitionName(LpMetadataBlockDevice* device, const std::string& name);
 bool UpdatePartitionGroupName(LpMetadataPartitionGroup* group, const std::string& name);
diff --git a/fs_mgr/liblp/utility_test.cpp b/fs_mgr/liblp/utility_test.cpp
index cac3989..b64861d 100644
--- a/fs_mgr/liblp/utility_test.cpp
+++ b/fs_mgr/liblp/utility_test.cpp
@@ -64,9 +64,9 @@
     EXPECT_EQ(AlignTo(555, 1024), 1024);
     EXPECT_EQ(AlignTo(555, 1000), 1000);
     EXPECT_EQ(AlignTo(0, 1024), 0);
-    EXPECT_EQ(AlignTo(54, 32, 30), 62);
-    EXPECT_EQ(AlignTo(32, 32, 30), 62);
-    EXPECT_EQ(AlignTo(17, 32, 30), 30);
+    EXPECT_EQ(AlignTo(54, 32), 64);
+    EXPECT_EQ(AlignTo(32, 32), 32);
+    EXPECT_EQ(AlignTo(17, 32), 32);
 }
 
 TEST(liblp, GetPartitionSlotSuffix) {
diff --git a/liblog/Android.bp b/liblog/Android.bp
index 0b98e1a..6051ac7 100644
--- a/liblog/Android.bp
+++ b/liblog/Android.bp
@@ -42,6 +42,7 @@
         "//apex_available:platform",
         "//apex_available:anyapex",
     ],
+    min_sdk_version: "29",
     native_bridge_supported: true,
     export_include_dirs: ["include"],
     system_shared_libs: [],