recovery: Refactor logging code into logging.cpp

Move common logging related functions to
rotate_logs.cpp, and rename that to logging.cpp.

Test: Recovery works
Bug: 78793464
Merged-In: I00f20a79a296680122b8437d54a87897c5cb2fc7
Change-Id: I00f20a79a296680122b8437d54a87897c5cb2fc7

Android.bp

@@ -89,8 +89,8 @@ cc_binary {
     ],
 
     srcs: [
+        "logging.cpp",
         "recovery-persist.cpp",
-        "rotate_logs.cpp",
     ],
 
     shared_libs: [
@@ -98,6 +98,10 @@ cc_binary {
         "liblog",
     ],
 
+    static_libs: [
+        "libotautil",
+    ],
+
     init_rc: [
         "recovery-persist.rc",
     ],
@@ -112,8 +116,8 @@ cc_binary {
     ],
 
     srcs: [
+        "logging.cpp",
         "recovery-refresh.cpp",
-        "rotate_logs.cpp",
     ],
 
     shared_libs: [
@@ -121,6 +125,10 @@ cc_binary {
         "liblog",
     ],
 
+    static_libs: [
+        "libotautil",
+    ],
+
     init_rc: [
         "recovery-refresh.rc",
     ],

Android.mk

@@ -126,10 +126,10 @@ LOCAL_SRC_FILES := \
     adb_install.cpp \
     device.cpp \
     fuse_sdcard_provider.cpp \
+    logging.cpp \
     recovery.cpp \
     recovery_main.cpp \
     roots.cpp \
-    rotate_logs.cpp \
 
 LOCAL_MODULE := recovery
 

common.h

@@ -27,7 +27,9 @@
 static constexpr int kRecoveryApiVersion = 3;
 
 class RecoveryUI;
+struct selabel_handle;
 
+extern struct selabel_handle* sehandle;
 extern RecoveryUI* ui;
 extern bool modified_flash;
 
@@ -37,13 +39,6 @@ extern std::string stage;
 // The reason argument provided in "--reason=".
 extern const char* reason;
 
-// fopen(3)'s the given file, by mounting volumes and making parent dirs as necessary. Returns the
-// file pointer, or nullptr on error.
-FILE* fopen_path(const std::string& path, const char* mode);
-
-// In turn fflush(3)'s, fsync(3)'s and fclose(3)'s the given stream.
-void check_and_fclose(FILE* fp, const std::string& name);
-
 void ui_print(const char* format, ...) __printflike(1, 2);
 
 bool is_ro_debuggable();

logging.cpp

@@ -0,0 +1,243 @@
+/*
+ * Copyright (C) 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 "logging.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/klog.h>
+#include <sys/types.h>
+
+#include <string>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
+#include <android-base/stringprintf.h>
+#include <private/android_filesystem_config.h> /* for AID_SYSTEM */
+#include <private/android_logger.h>            /* private pmsg functions */
+
+#include "common.h"
+#include "otautil/dirutil.h"
+#include "otautil/paths.h"
+#include "roots.h"
+
+static constexpr const char* LOG_FILE = "/cache/recovery/log";
+static constexpr const char* LAST_INSTALL_FILE = "/cache/recovery/last_install";
+static constexpr const char* LAST_KMSG_FILE = "/cache/recovery/last_kmsg";
+static constexpr const char* LAST_LOG_FILE = "/cache/recovery/last_log";
+
+static const std::string LAST_KMSG_FILTER = "recovery/last_kmsg";
+static const std::string LAST_LOG_FILTER = "recovery/last_log";
+
+// fopen(3)'s the given file, by mounting volumes and making parent dirs as necessary. Returns the
+// file pointer, or nullptr on error.
+static FILE* fopen_path(const std::string& path, const char* mode) {
+  if (ensure_path_mounted(path.c_str()) != 0) {
+    LOG(ERROR) << "Can't mount " << path;
+    return nullptr;
+  }
+
+  // When writing, try to create the containing directory, if necessary. Use generous permissions,
+  // the system (init.rc) will reset them.
+  if (strchr("wa", mode[0])) {
+    mkdir_recursively(path, 0777, true, sehandle);
+  }
+  return fopen(path.c_str(), mode);
+}
+
+void check_and_fclose(FILE* fp, const std::string& name) {
+  fflush(fp);
+  if (fsync(fileno(fp)) == -1) {
+    PLOG(ERROR) << "Failed to fsync " << name;
+  }
+  if (ferror(fp)) {
+    PLOG(ERROR) << "Error in " << name;
+  }
+  fclose(fp);
+}
+
+// close a file, log an error if the error indicator is set
+ssize_t logbasename(log_id_t /* id */, char /* prio */, const char* filename, const char* /* buf */,
+                    size_t len, void* arg) {
+  bool* do_rotate = static_cast<bool*>(arg);
+  if (LAST_KMSG_FILTER.find(filename) != std::string::npos ||
+      LAST_LOG_FILTER.find(filename) != std::string::npos) {
+    *do_rotate = true;
+  }
+  return len;
+}
+
+ssize_t logrotate(log_id_t id, char prio, const char* filename, const char* buf, size_t len,
+                  void* arg) {
+  bool* do_rotate = static_cast<bool*>(arg);
+  if (!*do_rotate) {
+    return __android_log_pmsg_file_write(id, prio, filename, buf, len);
+  }
+
+  std::string name(filename);
+  size_t dot = name.find_last_of('.');
+  std::string sub = name.substr(0, dot);
+
+  if (LAST_KMSG_FILTER.find(sub) == std::string::npos &&
+      LAST_LOG_FILTER.find(sub) == std::string::npos) {
+    return __android_log_pmsg_file_write(id, prio, filename, buf, len);
+  }
+
+  // filename rotation
+  if (dot == std::string::npos) {
+    name += ".1";
+  } else {
+    std::string number = name.substr(dot + 1);
+    if (!isdigit(number[0])) {
+      name += ".1";
+    } else {
+      size_t i;
+      if (!android::base::ParseUint(number, &i)) {
+        LOG(ERROR) << "failed to parse uint in " << number;
+        return -1;
+      }
+      name = sub + "." + std::to_string(i + 1);
+    }
+  }
+
+  return __android_log_pmsg_file_write(id, prio, name.c_str(), buf, len);
+}
+
+// Rename last_log -> last_log.1 -> last_log.2 -> ... -> last_log.$max.
+// Similarly rename last_kmsg -> last_kmsg.1 -> ... -> last_kmsg.$max.
+// Overwrite any existing last_log.$max and last_kmsg.$max.
+void rotate_logs(const char* last_log_file, const char* last_kmsg_file) {
+  // Logs should only be rotated once.
+  static bool rotated = false;
+  if (rotated) {
+    return;
+  }
+  rotated = true;
+
+  for (int i = KEEP_LOG_COUNT - 1; i >= 0; --i) {
+    std::string old_log = android::base::StringPrintf("%s", last_log_file);
+    if (i > 0) {
+      old_log += "." + std::to_string(i);
+    }
+    std::string new_log = android::base::StringPrintf("%s.%d", last_log_file, i + 1);
+    // Ignore errors if old_log doesn't exist.
+    rename(old_log.c_str(), new_log.c_str());
+
+    std::string old_kmsg = android::base::StringPrintf("%s", last_kmsg_file);
+    if (i > 0) {
+      old_kmsg += "." + std::to_string(i);
+    }
+    std::string new_kmsg = android::base::StringPrintf("%s.%d", last_kmsg_file, i + 1);
+    rename(old_kmsg.c_str(), new_kmsg.c_str());
+  }
+}
+
+// Writes content to the current pmsg session.
+static ssize_t __pmsg_write(const std::string& filename, const std::string& buf) {
+  return __android_log_pmsg_file_write(LOG_ID_SYSTEM, ANDROID_LOG_INFO, filename.c_str(),
+                                       buf.data(), buf.size());
+}
+
+void copy_log_file_to_pmsg(const std::string& source, const std::string& destination) {
+  std::string content;
+  android::base::ReadFileToString(source, &content);
+  __pmsg_write(destination, content);
+}
+
+// How much of the temp log we have copied to the copy in cache.
+static off_t tmplog_offset = 0;
+
+void reset_tmplog_offset() {
+  tmplog_offset = 0;
+}
+
+void copy_log_file(const std::string& source, const std::string& destination, bool append) {
+  FILE* dest_fp = fopen_path(destination, append ? "ae" : "we");
+  if (dest_fp == nullptr) {
+    PLOG(ERROR) << "Can't open " << destination;
+  } else {
+    FILE* source_fp = fopen(source.c_str(), "re");
+    if (source_fp != nullptr) {
+      if (append) {
+        fseeko(source_fp, tmplog_offset, SEEK_SET);  // Since last write
+      }
+      char buf[4096];
+      size_t bytes;
+      while ((bytes = fread(buf, 1, sizeof(buf), source_fp)) != 0) {
+        fwrite(buf, 1, bytes, dest_fp);
+      }
+      if (append) {
+        tmplog_offset = ftello(source_fp);
+      }
+      check_and_fclose(source_fp, source);
+    }
+    check_and_fclose(dest_fp, destination);
+  }
+}
+
+void copy_logs(bool modified_flash, bool has_cache) {
+  // We only rotate and record the log of the current session if there are actual attempts to modify
+  // the flash, such as wipes, installs from BCB or menu selections. This is to avoid unnecessary
+  // rotation (and possible deletion) of log files, if it does not do anything loggable.
+  if (!modified_flash) {
+    return;
+  }
+
+  // Always write to pmsg, this allows the OTA logs to be caught in `logcat -L`.
+  copy_log_file_to_pmsg(Paths::Get().temporary_log_file(), LAST_LOG_FILE);
+  copy_log_file_to_pmsg(Paths::Get().temporary_install_file(), LAST_INSTALL_FILE);
+
+  // We can do nothing for now if there's no /cache partition.
+  if (!has_cache) {
+    return;
+  }
+
+  ensure_path_mounted(LAST_LOG_FILE);
+  ensure_path_mounted(LAST_KMSG_FILE);
+  rotate_logs(LAST_LOG_FILE, LAST_KMSG_FILE);
+
+  // Copy logs to cache so the system can find out what happened.
+  copy_log_file(Paths::Get().temporary_log_file(), LOG_FILE, true);
+  copy_log_file(Paths::Get().temporary_log_file(), LAST_LOG_FILE, false);
+  copy_log_file(Paths::Get().temporary_install_file(), LAST_INSTALL_FILE, false);
+  save_kernel_log(LAST_KMSG_FILE);
+  chmod(LOG_FILE, 0600);
+  chown(LOG_FILE, AID_SYSTEM, AID_SYSTEM);
+  chmod(LAST_KMSG_FILE, 0600);
+  chown(LAST_KMSG_FILE, AID_SYSTEM, AID_SYSTEM);
+  chmod(LAST_LOG_FILE, 0640);
+  chmod(LAST_INSTALL_FILE, 0644);
+  sync();
+}
+
+// Read from kernel log into buffer and write out to file.
+void save_kernel_log(const char* destination) {
+  int klog_buf_len = klogctl(KLOG_SIZE_BUFFER, 0, 0);
+  if (klog_buf_len <= 0) {
+    PLOG(ERROR) << "Error getting klog size";
+    return;
+  }
+
+  std::string buffer(klog_buf_len, 0);
+  int n = klogctl(KLOG_READ_ALL, &buffer[0], klog_buf_len);
+  if (n == -1) {
+    PLOG(ERROR) << "Error in reading klog";
+    return;
+  }
+  buffer.resize(n);
+  android::base::WriteStringToFile(buffer, destination);
+}

logging.h

@@ -14,12 +14,14 @@
  * limitations under the License.
  */
 
-#ifndef _ROTATE_LOGS_H
+#ifndef _LOGGING_H
-#define _ROTATE_LOGS_H
+#define _LOGGING_H
 
 #include <stddef.h>
 #include <sys/types.h>
 
+#include <string>
+
 #include <log/log_id.h>
 
 static constexpr int KEEP_LOG_COUNT = 10;
@@ -35,4 +37,14 @@ ssize_t logrotate(log_id_t id, char prio, const char* filename, const char* buf,
 // Overwrite any existing last_log.$max and last_kmsg.$max.
 void rotate_logs(const char* last_log_file, const char* last_kmsg_file);
 
-#endif //_ROTATE_LOG_H
+// In turn fflush(3)'s, fsync(3)'s and fclose(3)'s the given stream.
+void check_and_fclose(FILE* fp, const std::string& name);
+
+void copy_log_file_to_pmsg(const std::string& source, const std::string& destination);
+void copy_log_file(const std::string& source, const std::string& destination, bool append);
+void copy_logs(bool modified_flash, bool has_cache);
+void reset_tmplog_offset();
+
+void save_kernel_log(const char* destination);
+
+#endif  //_LOGGING_H

recovery-persist.cpp

@@ -41,7 +41,7 @@
 #include <android-base/logging.h>
 #include <private/android_logger.h> /* private pmsg functions */
 
-#include "rotate_logs.h"
+#include "logging.h"
 
 static const char *LAST_LOG_FILE = "/data/misc/recovery/last_log";
 static const char *LAST_PMSG_FILE = "/sys/fs/pstore/pmsg-ramoops-0";

recovery-refresh.cpp

@@ -42,7 +42,7 @@
 
 #include <private/android_logger.h> /* private pmsg functions */
 
-#include "rotate_logs.h"
+#include "logging.h"
 
 int main(int argc, char **argv) {
     static const char filter[] = "recovery/";

recovery.cpp

@@ -29,7 +29,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <sys/klog.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -53,8 +52,6 @@
 #include <cutils/android_reboot.h>
 #include <cutils/properties.h> /* for property_list */
 #include <healthd/BatteryMonitor.h>
-#include <private/android_filesystem_config.h>  /* for AID_SYSTEM */
-#include <private/android_logger.h>             /* private pmsg functions */
 #include <selinux/android.h>
 #include <selinux/label.h>
 #include <selinux/selinux.h>
@@ -66,21 +63,19 @@
 #include "fuse_sdcard_provider.h"
 #include "fuse_sideload.h"
 #include "install.h"
+#include "logging.h"
 #include "minui/minui.h"
 #include "otautil/dirutil.h"
 #include "otautil/error_code.h"
 #include "otautil/paths.h"
 #include "otautil/sysutil.h"
 #include "roots.h"
-#include "rotate_logs.h"
 #include "screen_ui.h"
 #include "stub_ui.h"
 #include "ui.h"
 
 static constexpr const char* CACHE_LOG_DIR = "/cache/recovery";
 static constexpr const char* COMMAND_FILE = "/cache/recovery/command";
-static constexpr const char* LOG_FILE = "/cache/recovery/log";
-static constexpr const char* LAST_INSTALL_FILE = "/cache/recovery/last_install";
 static constexpr const char* LAST_KMSG_FILE = "/cache/recovery/last_kmsg";
 static constexpr const char* LAST_LOG_FILE = "/cache/recovery/last_log";
 static constexpr const char* LOCALE_FILE = "/cache/recovery/last_locale";
@@ -149,31 +144,6 @@ struct selabel_handle* sehandle;
  *    7b. the user reboots (pulling the battery, etc) into the main system
  */
 
-FILE* fopen_path(const std::string& path, const char* mode) {
-  if (ensure_path_mounted(path.c_str()) != 0) {
-    LOG(ERROR) << "Can't mount " << path;
-    return nullptr;
-  }
-
-  // When writing, try to create the containing directory, if necessary. Use generous permissions,
-  // the system (init.rc) will reset them.
-  if (strchr("wa", mode[0])) {
-    mkdir_recursively(path, 0777, true, sehandle);
-  }
-  return fopen(path.c_str(), mode);
-}
-
-void check_and_fclose(FILE* fp, const std::string& name) {
-  fflush(fp);
-  if (fsync(fileno(fp)) == -1) {
-    PLOG(ERROR) << "Failed to fsync " << name;
-  }
-  if (ferror(fp)) {
-    PLOG(ERROR) << "Error in " << name;
-  }
-  fclose(fp);
-}
-
 bool is_ro_debuggable() {
     return android::base::GetBoolProperty("ro.debuggable", false);
 }
@@ -259,98 +229,6 @@ static void set_sdcard_update_bootloader_message() {
   }
 }
 
-// Read from kernel log into buffer and write out to file.
-static void save_kernel_log(const char* destination) {
-    int klog_buf_len = klogctl(KLOG_SIZE_BUFFER, 0, 0);
-    if (klog_buf_len <= 0) {
-        PLOG(ERROR) << "Error getting klog size";
-        return;
-    }
-
-    std::string buffer(klog_buf_len, 0);
-    int n = klogctl(KLOG_READ_ALL, &buffer[0], klog_buf_len);
-    if (n == -1) {
-        PLOG(ERROR) << "Error in reading klog";
-        return;
-    }
-    buffer.resize(n);
-    android::base::WriteStringToFile(buffer, destination);
-}
-
-// Writes content to the current pmsg session.
-static ssize_t __pmsg_write(const std::string& filename, const std::string& buf) {
-  return __android_log_pmsg_file_write(LOG_ID_SYSTEM, ANDROID_LOG_INFO, filename.c_str(),
-                                       buf.data(), buf.size());
-}
-
-static void copy_log_file_to_pmsg(const std::string& source, const std::string& destination) {
-  std::string content;
-  android::base::ReadFileToString(source, &content);
-  __pmsg_write(destination, content);
-}
-
-// How much of the temp log we have copied to the copy in cache.
-static off_t tmplog_offset = 0;
-
-static void copy_log_file(const std::string& source, const std::string& destination, bool append) {
-  FILE* dest_fp = fopen_path(destination, append ? "ae" : "we");
-  if (dest_fp == nullptr) {
-    PLOG(ERROR) << "Can't open " << destination;
-  } else {
-    FILE* source_fp = fopen(source.c_str(), "re");
-    if (source_fp != nullptr) {
-      if (append) {
-        fseeko(source_fp, tmplog_offset, SEEK_SET);  // Since last write
-      }
-      char buf[4096];
-      size_t bytes;
-      while ((bytes = fread(buf, 1, sizeof(buf), source_fp)) != 0) {
-        fwrite(buf, 1, bytes, dest_fp);
-      }
-      if (append) {
-        tmplog_offset = ftello(source_fp);
-      }
-      check_and_fclose(source_fp, source);
-    }
-    check_and_fclose(dest_fp, destination);
-  }
-}
-
-static void copy_logs() {
-  // We only rotate and record the log of the current session if there are actual attempts to modify
-  // the flash, such as wipes, installs from BCB or menu selections. This is to avoid unnecessary
-  // rotation (and possible deletion) of log files, if it does not do anything loggable.
-  if (!modified_flash) {
-    return;
-  }
-
-  // Always write to pmsg, this allows the OTA logs to be caught in `logcat -L`.
-  copy_log_file_to_pmsg(Paths::Get().temporary_log_file(), LAST_LOG_FILE);
-  copy_log_file_to_pmsg(Paths::Get().temporary_install_file(), LAST_INSTALL_FILE);
-
-  // We can do nothing for now if there's no /cache partition.
-  if (!has_cache) {
-    return;
-  }
-
-  ensure_path_mounted(LAST_LOG_FILE);
-  ensure_path_mounted(LAST_KMSG_FILE);
-  rotate_logs(LAST_LOG_FILE, LAST_KMSG_FILE);
-
-  // Copy logs to cache so the system can find out what happened.
-  copy_log_file(Paths::Get().temporary_log_file(), LOG_FILE, true);
-  copy_log_file(Paths::Get().temporary_log_file(), LAST_LOG_FILE, false);
-  copy_log_file(Paths::Get().temporary_install_file(), LAST_INSTALL_FILE, false);
-  save_kernel_log(LAST_KMSG_FILE);
-  chmod(LOG_FILE, 0600);
-  chown(LOG_FILE, AID_SYSTEM, AID_SYSTEM);
-  chmod(LAST_KMSG_FILE, 0600);
-  chown(LAST_KMSG_FILE, AID_SYSTEM, AID_SYSTEM);
-  chmod(LAST_LOG_FILE, 0640);
-  chmod(LAST_INSTALL_FILE, 0644);
-  sync();
-}
-
 // Clear the recovery command and prepare to boot a (hopefully working) system,
 // copy our log file to cache as well (for the system to read). This function is
 // idempotent: call it as many times as you like.
@@ -366,7 +244,7 @@ static void finish_recovery() {
     }
   }
 
-  copy_logs();
+  copy_logs(modified_flash, has_cache);
 
   // Reset to normal system boot so recovery won't cycle indefinitely.
   std::string err;
@@ -482,8 +360,8 @@ static bool erase_volume(const char* volume) {
     // Any part of the log we'd copied to cache is now gone.
     // Reset the pointer so we copy from the beginning of the temp
     // log.
-    tmplog_offset = 0;
+    reset_tmplog_offset();
-    copy_logs();
+    copy_logs(modified_flash, has_cache);
   }
 
   return (result == 0);
@@ -1000,7 +878,7 @@ static Device::BuiltinAction prompt_and_wait(Device* device, int status) {
           if (status != INSTALL_SUCCESS) {
             ui->SetBackground(RecoveryUI::ERROR);
             ui->Print("Installation aborted.\n");
-            copy_logs();
+            copy_logs(modified_flash, has_cache);
           } else if (!ui->IsTextVisible()) {
             return Device::NO_ACTION;  // reboot if logs aren't visible
           } else {
@@ -1374,7 +1252,7 @@ int start_recovery(int argc, char** argv) {
         // RETRY_LIMIT times before we abandon this OTA update.
         static constexpr int RETRY_LIMIT = 4;
         if (status == INSTALL_RETRY && retry_count < RETRY_LIMIT) {
-          copy_logs();
+          copy_logs(modified_flash, has_cache);
           retry_count += 1;
           set_retry_bootloader_message(retry_count, args);
           // Print retry count on screen.

recovery_main.cpp

@@ -24,10 +24,10 @@
 #include <private/android_logger.h> /* private pmsg functions */
 
 #include "common.h"
+#include "logging.h"
 #include "minadbd/minadbd.h"
 #include "otautil/paths.h"
 #include "private/recovery.h"
-#include "rotate_logs.h"
 #include "ui.h"
 
 static void UiLogger(android::base::LogId /* id */, android::base::LogSeverity severity,

rotate_logs.cpp

@@ -1,107 +0,0 @@
-/*
- * Copyright (C) 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 "rotate_logs.h"
-
-#include <stdio.h>
-#include <string.h>
-#include <sys/types.h>
-
-#include <string>
-
-#include <android-base/file.h>
-#include <android-base/logging.h>
-#include <android-base/parseint.h>
-#include <android-base/stringprintf.h>
-#include <private/android_logger.h> /* private pmsg functions */
-
-static const std::string LAST_KMSG_FILTER = "recovery/last_kmsg";
-static const std::string LAST_LOG_FILTER = "recovery/last_log";
-
-ssize_t logbasename(log_id_t /* id */, char /* prio */, const char* filename, const char* /* buf */,
-                    size_t len, void* arg) {
-  bool* do_rotate = static_cast<bool*>(arg);
-  if (LAST_KMSG_FILTER.find(filename) != std::string::npos ||
-      LAST_LOG_FILTER.find(filename) != std::string::npos) {
-    *do_rotate = true;
-  }
-  return len;
-}
-
-ssize_t logrotate(log_id_t id, char prio, const char* filename, const char* buf, size_t len,
-                  void* arg) {
-  bool* do_rotate = static_cast<bool*>(arg);
-  if (!*do_rotate) {
-    return __android_log_pmsg_file_write(id, prio, filename, buf, len);
-  }
-
-  std::string name(filename);
-  size_t dot = name.find_last_of('.');
-  std::string sub = name.substr(0, dot);
-
-  if (LAST_KMSG_FILTER.find(sub) == std::string::npos &&
-      LAST_LOG_FILTER.find(sub) == std::string::npos) {
-    return __android_log_pmsg_file_write(id, prio, filename, buf, len);
-  }
-
-  // filename rotation
-  if (dot == std::string::npos) {
-    name += ".1";
-  } else {
-    std::string number = name.substr(dot + 1);
-    if (!isdigit(number[0])) {
-      name += ".1";
-    } else {
-      size_t i;
-      if (!android::base::ParseUint(number, &i)) {
-        LOG(ERROR) << "failed to parse uint in " << number;
-        return -1;
-      }
-      name = sub + "." + std::to_string(i + 1);
-    }
-  }
-
-  return __android_log_pmsg_file_write(id, prio, name.c_str(), buf, len);
-}
-
-// Rename last_log -> last_log.1 -> last_log.2 -> ... -> last_log.$max.
-// Similarly rename last_kmsg -> last_kmsg.1 -> ... -> last_kmsg.$max.
-// Overwrite any existing last_log.$max and last_kmsg.$max.
-void rotate_logs(const char* last_log_file, const char* last_kmsg_file) {
-  // Logs should only be rotated once.
-  static bool rotated = false;
-  if (rotated) {
-    return;
-  }
-  rotated = true;
-
-  for (int i = KEEP_LOG_COUNT - 1; i >= 0; --i) {
-    std::string old_log = android::base::StringPrintf("%s", last_log_file);
-    if (i > 0) {
-      old_log += "." + std::to_string(i);
-    }
-    std::string new_log = android::base::StringPrintf("%s.%d", last_log_file, i + 1);
-    // Ignore errors if old_log doesn't exist.
-    rename(old_log.c_str(), new_log.c_str());
-
-    std::string old_kmsg = android::base::StringPrintf("%s", last_kmsg_file);
-    if (i > 0) {
-      old_kmsg += "." + std::to_string(i);
-    }
-    std::string new_kmsg = android::base::StringPrintf("%s.%d", last_kmsg_file, i + 1);
-    rename(old_kmsg.c_str(), new_kmsg.c_str());
-  }
-}