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
31static const std::string LAST_KMSG_FILTER = "recovery/last_kmsg";
32static const std::string LAST_LOG_FILTER = "recovery/last_log";
33
34ssize_t logbasename(log_id_t /* id */, char /* prio */, const char* filename, const char* /* buf */,
35                    size_t len, void* arg) {
36  bool* do_rotate = static_cast<bool*>(arg);
37  if (LAST_KMSG_FILTER.find(filename) != std::string::npos ||
38      LAST_LOG_FILTER.find(filename) != std::string::npos) {
39    *do_rotate = true;
40  }
41  return len;
42}
43
44ssize_t logrotate(log_id_t id, char prio, const char* filename, const char* buf, size_t len,
45                  void* arg) {
46  bool* do_rotate = static_cast<bool*>(arg);
47  if (!*do_rotate) {
48    return __android_log_pmsg_file_write(id, prio, filename, buf, len);
49  }
50
51  std::string name(filename);
52  size_t dot = name.find_last_of('.');
53  std::string sub = name.substr(0, dot);
54
55  if (LAST_KMSG_FILTER.find(sub) == std::string::npos &&
56      LAST_LOG_FILTER.find(sub) == std::string::npos) {
57    return __android_log_pmsg_file_write(id, prio, filename, buf, len);
58  }
59
60  // filename rotation
61  if (dot == std::string::npos) {
62    name += ".1";
63  } else {
64    std::string number = name.substr(dot + 1);
65    if (!isdigit(number[0])) {
66      name += ".1";
67    } else {
68      size_t i;
69      if (!android::base::ParseUint(number, &i)) {
70        LOG(ERROR) << "failed to parse uint in " << number;
71        return -1;
72      }
73      name = sub + "." + std::to_string(i + 1);
74    }
75  }
76
77  return __android_log_pmsg_file_write(id, prio, name.c_str(), buf, len);
78}
79
80// Rename last_log -> last_log.1 -> last_log.2 -> ... -> last_log.$max.
81// Similarly rename last_kmsg -> last_kmsg.1 -> ... -> last_kmsg.$max.
82// Overwrite any existing last_log.$max and last_kmsg.$max.
83void rotate_logs(const char* last_log_file, const char* last_kmsg_file) {
84  // Logs should only be rotated once.
85  static bool rotated = false;
86  if (rotated) {
87    return;
88  }
89  rotated = true;
90
91  for (int i = KEEP_LOG_COUNT - 1; i >= 0; --i) {
92    std::string old_log = android::base::StringPrintf("%s", last_log_file);
93    if (i > 0) {
94      old_log += "." + std::to_string(i);
95    }
96    std::string new_log = android::base::StringPrintf("%s.%d", last_log_file, i + 1);
97    // Ignore errors if old_log doesn't exist.
98    rename(old_log.c_str(), new_log.c_str());
99
100    std::string old_kmsg = android::base::StringPrintf("%s", last_kmsg_file);
101    if (i > 0) {
102      old_kmsg += "." + std::to_string(i);
103    }
104    std::string new_kmsg = android::base::StringPrintf("%s.%d", last_kmsg_file, i + 1);
105    rename(old_kmsg.c_str(), new_kmsg.c_str());
106  }
107}
108