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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "rotate_logs.h"
     18 
     19 #include <stdio.h>
     20 #include <string.h>
     21 #include <sys/types.h>
     22 
     23 #include <string>
     24 
     25 #include <android-base/file.h>
     26 #include <android-base/logging.h>
     27 #include <android-base/parseint.h>
     28 #include <android-base/stringprintf.h>
     29 #include <private/android_logger.h> /* private pmsg functions */
     30 
     31 static const std::string LAST_KMSG_FILTER = "recovery/last_kmsg";
     32 static const std::string LAST_LOG_FILTER = "recovery/last_log";
     33 
     34 ssize_t logbasename(
     35         log_id_t /* logId */,
     36         char /* prio */,
     37         const char *filename,
     38         const char * /* buf */, size_t len,
     39         void *arg) {
     40     bool* doRotate  = static_cast<bool*>(arg);
     41     if (LAST_KMSG_FILTER.find(filename) != std::string::npos ||
     42             LAST_LOG_FILTER.find(filename) != std::string::npos) {
     43         *doRotate = true;
     44     }
     45     return len;
     46 }
     47 
     48 ssize_t logrotate(
     49         log_id_t logId,
     50         char prio,
     51         const char *filename,
     52         const char *buf, size_t len,
     53         void *arg) {
     54     bool* doRotate  = static_cast<bool*>(arg);
     55     if (!*doRotate) {
     56         return __android_log_pmsg_file_write(logId, prio, filename, buf, len);
     57     }
     58 
     59     std::string name(filename);
     60     size_t dot = name.find_last_of('.');
     61     std::string sub = name.substr(0, dot);
     62 
     63     if (LAST_KMSG_FILTER.find(sub) == std::string::npos &&
     64             LAST_LOG_FILTER.find(sub) == std::string::npos) {
     65         return __android_log_pmsg_file_write(logId, prio, filename, buf, len);
     66     }
     67 
     68     // filename rotation
     69     if (dot == std::string::npos) {
     70         name += ".1";
     71     } else {
     72         std::string number = name.substr(dot + 1);
     73         if (!isdigit(number[0])) {
     74             name += ".1";
     75         } else {
     76             size_t i;
     77             if (!android::base::ParseUint(number, &i)) {
     78                 LOG(ERROR) << "failed to parse uint in " << number;
     79                 return -1;
     80             }
     81             name = sub + "." + std::to_string(i + 1);
     82         }
     83     }
     84 
     85     return __android_log_pmsg_file_write(logId, prio, name.c_str(), buf, len);
     86 }
     87 
     88 // Rename last_log -> last_log.1 -> last_log.2 -> ... -> last_log.$max.
     89 // Similarly rename last_kmsg -> last_kmsg.1 -> ... -> last_kmsg.$max.
     90 // Overwrite any existing last_log.$max and last_kmsg.$max.
     91 void rotate_logs(const char* last_log_file, const char* last_kmsg_file) {
     92     // Logs should only be rotated once.
     93     static bool rotated = false;
     94     if (rotated) {
     95         return;
     96     }
     97     rotated = true;
     98 
     99     for (int i = KEEP_LOG_COUNT - 1; i >= 0; --i) {
    100         std::string old_log = android::base::StringPrintf("%s", last_log_file);
    101         if (i > 0) {
    102           old_log += "." + std::to_string(i);
    103         }
    104         std::string new_log = android::base::StringPrintf("%s.%d", last_log_file, i+1);
    105         // Ignore errors if old_log doesn't exist.
    106         rename(old_log.c_str(), new_log.c_str());
    107 
    108         std::string old_kmsg = android::base::StringPrintf("%s", last_kmsg_file);
    109         if (i > 0) {
    110           old_kmsg += "." + std::to_string(i);
    111         }
    112         std::string new_kmsg = android::base::StringPrintf("%s.%d", last_kmsg_file, i+1);
    113         rename(old_kmsg.c_str(), new_kmsg.c_str());
    114     }
    115 }
    116