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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 #define LOG_TAG "recovery-refresh"
     18 
     19 //
     20 // Strictly to deal with reboot into system after OTA, then
     21 // reboot while in system before boot complete landing us back
     22 // into recovery to continue with any mitigations with retained
     23 // log history. This simply refreshes the pmsg files from
     24 // the last pmsg file contents.
     25 //
     26 // Usage:
     27 //    recovery-refresh [--force-rotate|--rotate]
     28 //
     29 //    All file content representing in the recovery/ directory stored in
     30 //    /sys/fs/pstore/pmsg-ramoops-0 in logger format that reside in the
     31 //    LOG_ID_SYSTEM buffer at ANDROID_LOG_INFO priority or higher is
     32 //    refreshed into /dev/pmsg0. This ensures that an unexpected reboot
     33 //    before recovery-persist is run will still contain the associated
     34 //    pmsg Android Logger content.
     35 //
     36 //    --force-rotate  recovery/last_kmsg and recovery.last_log files are
     37 //                    rotated with .<number> suffixes upwards.
     38 //    --rotate        rotated only if rocovery/last_msg or recovery/last_log
     39 //                    exist, otherwise perform 1:1 refresh.
     40 //
     41 
     42 #include <string.h>
     43 
     44 #include <string>
     45 
     46 #include <android/log.h> /* Android Log Priority Tags */
     47 #include <log/logger.h> /* Android Log packet format */
     48 #include <private/android_logger.h> /* private pmsg functions */
     49 
     50 static const char LAST_KMSG_FILE[] = "recovery/last_kmsg";
     51 static const char LAST_LOG_FILE[] = "recovery/last_log";
     52 
     53 static ssize_t logbasename(
     54         log_id_t /* logId */,
     55         char /* prio */,
     56         const char *filename,
     57         const char * /* buf */, size_t len,
     58         void *arg) {
     59     if (strstr(LAST_KMSG_FILE, filename) ||
     60             strstr(LAST_LOG_FILE, filename)) {
     61         bool *doRotate = reinterpret_cast<bool *>(arg);
     62         *doRotate = true;
     63     }
     64     return len;
     65 }
     66 
     67 static ssize_t logrotate(
     68         log_id_t logId,
     69         char prio,
     70         const char *filename,
     71         const char *buf, size_t len,
     72         void *arg) {
     73     bool *doRotate = reinterpret_cast<bool *>(arg);
     74     if (!*doRotate) {
     75         return __android_log_pmsg_file_write(logId, prio, filename, buf, len);
     76     }
     77 
     78     std::string name(filename);
     79     size_t dot = name.find_last_of(".");
     80     std::string sub = name.substr(0, dot);
     81 
     82     if (!strstr(LAST_KMSG_FILE, sub.c_str()) &&
     83                 !strstr(LAST_LOG_FILE, sub.c_str())) {
     84         return __android_log_pmsg_file_write(logId, prio, filename, buf, len);
     85     }
     86 
     87     // filename rotation
     88     if (dot == std::string::npos) {
     89         name += ".1";
     90     } else {
     91         std::string number = name.substr(dot + 1);
     92         if (!isdigit(number.data()[0])) {
     93             name += ".1";
     94         } else {
     95             unsigned long long i = std::stoull(number);
     96             name = sub + "." + std::to_string(i + 1);
     97         }
     98     }
     99 
    100     return __android_log_pmsg_file_write(logId, prio, name.c_str(), buf, len);
    101 }
    102 
    103 int main(int argc, char **argv) {
    104     static const char filter[] = "recovery/";
    105     static const char force_rotate_flag[] = "--force-rotate";
    106     static const char rotate_flag[] = "--rotate";
    107     ssize_t ret;
    108     bool doRotate = false;
    109 
    110     // Take last pmsg contents and rewrite it to the current pmsg session.
    111     if ((argc <= 1) || !argv[1] ||
    112             (((doRotate = strcmp(argv[1], rotate_flag))) &&
    113                 strcmp(argv[1], force_rotate_flag))) {
    114         doRotate = false;
    115     } else if (!doRotate) {
    116         // Do we need to rotate?
    117         __android_log_pmsg_file_read(
    118             LOG_ID_SYSTEM, ANDROID_LOG_INFO, filter,
    119             logbasename, &doRotate);
    120     }
    121 
    122     // Take action to refresh pmsg contents
    123     ret = __android_log_pmsg_file_read(
    124         LOG_ID_SYSTEM, ANDROID_LOG_INFO, filter,
    125         logrotate, &doRotate);
    126 
    127     return (ret < 0) ? ret : 0;
    128 }
    129