3 files changed, 297 insertions, 0 deletions

diff --git a/otautil/Android.bp b/otautil/Android.bp
index c9ecba788..73398c3aa 100644
--- a/otautil/Android.bp
+++ b/otautil/Android.bp
@@ -40,6 +40,7 @@ cc_library_static {
         android: {
             srcs: [
                 "dirutil.cpp",
+                "logging.cpp",
                 "mounts.cpp",
                 "parse_install_logs.cpp",
                 "roots.cpp",
diff --git a/otautil/include/otautil/logging.h b/otautil/include/otautil/logging.h
new file mode 100644
index 000000000..c4f13292b
--- /dev/null
+++ b/otautil/include/otautil/logging.h
@@ -0,0 +1,51 @@
+/*
+ * 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.
+ */
+
+#ifndef _LOGGING_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;
+
+struct selabel_handle;
+
+ssize_t logbasename(log_id_t id, char prio, const char* filename, const char* buf, size_t len,
+                    void* arg);
+
+ssize_t logrotate(log_id_t id, char prio, const char* filename, const char* buf, size_t len,
+                  void* arg);
+
+// 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);
+
+// 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_logs(bool save_current_log, bool has_cache, const selabel_handle* sehandle);
+void reset_tmplog_offset();
+
+void save_kernel_log(const char* destination);
+
+#endif  //_LOGGING_H
diff --git a/otautil/logging.cpp b/otautil/logging.cpp
new file mode 100644
index 000000000..7c330ac61
--- /dev/null
+++ b/otautil/logging.cpp
@@ -0,0 +1,245 @@
+/*
+ * 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 "otautil/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 <selinux/label.h>
+
+#include "otautil/dirutil.h"
+#include "otautil/paths.h"
+#include "otautil/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, const selabel_handle* sehandle) {
+  if (ensure_path_mounted(path) != 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;
+}
+
+static void copy_log_file(const std::string& source, const std::string& destination, bool append,
+                          const selabel_handle* sehandle) {
+  FILE* dest_fp = fopen_path(destination, append ? "ae" : "we", sehandle);
+  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 save_current_log, bool has_cache, const selabel_handle* sehandle) {
+  // We only rotate and record the log of the current session if explicitly requested. This usually
+  // happens after wipes, installation 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 (!save_current_log) {
+    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, sehandle);
+  copy_log_file(Paths::Get().temporary_log_file(), LAST_LOG_FILE, false, sehandle);
+  copy_log_file(Paths::Get().temporary_install_file(), LAST_INSTALL_FILE, false, sehandle);
+  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);
+  chown(LAST_INSTALL_FILE, AID_SYSTEM, AID_SYSTEM);
+  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);
+}