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-rw-r--r--rotate_logs.cpp115
1 files changed, 115 insertions, 0 deletions
diff --git a/rotate_logs.cpp b/rotate_logs.cpp
new file mode 100644
index 000000000..fc220215e
--- /dev/null
+++ b/rotate_logs.cpp
@@ -0,0 +1,115 @@
+/*
+ * 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 /* logId */,
+ char /* prio */,
+ const char *filename,
+ const char * /* buf */, size_t len,
+ void *arg) {
+ bool* doRotate = static_cast<bool*>(arg);
+ if (LAST_KMSG_FILTER.find(filename) != std::string::npos ||
+ LAST_LOG_FILTER.find(filename) != std::string::npos) {
+ *doRotate = true;
+ }
+ return len;
+}
+
+ssize_t logrotate(
+ log_id_t logId,
+ char prio,
+ const char *filename,
+ const char *buf, size_t len,
+ void *arg) {
+ bool* doRotate = static_cast<bool*>(arg);
+ if (!*doRotate) {
+ return __android_log_pmsg_file_write(logId, 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(logId, 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(logId, 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());
+ }
+}