xpcom/base/LogModulePrefWatcher.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "LogModulePrefWatcher.h"
   8
   9 #include "mozilla/Logging.h"
  10 #include "mozilla/Preferences.h"
  11 #include "mozilla/Services.h"
  12 #include "nsIObserverService.h"
  13 #include "nsMemory.h"
  14 #include "nsString.h"
  15 #include "nsXULAppAPI.h"
  16 #include "base/process_util.h"
  17
  18 static const char kLoggingPrefPrefix[] = "logging.";
  19 static const char kLoggingConfigPrefPrefix[] = "logging.config";
  20 static const int kLoggingConfigPrefixLen = sizeof(kLoggingConfigPrefPrefix) - 1;
  21 static const char kLoggingPrefClearOnStartup[] =
  22     "logging.config.clear_on_startup";
  23 static const char kLoggingPrefLogFile[] = "logging.config.LOG_FILE";
  24 static const char kLoggingPrefAddTimestamp[] = "logging.config.add_timestamp";
  25 static const char kLoggingPrefSync[] = "logging.config.sync";
  26
  27 namespace mozilla {
  28
  29 NS_IMPL_ISUPPORTS(LogModulePrefWatcher, nsIObserver)
  30
  31 /**
  32  * Resets all the preferences in the logging. branch
  33  * This is needed because we may crash while logging, and this would cause us
  34  * to log after restarting as well.
  35  *
  36  * If logging after restart is desired, set the logging.config.clear_on_startup
  37  * pref to false, or use the MOZ_LOG_FILE and MOZ_LOG_MODULES env vars.
  38  */
  39 static void ResetExistingPrefs() {
  40   nsTArray<nsCString> names;
  41   nsresult rv =
  42       Preferences::GetRootBranch()->GetChildList(kLoggingPrefPrefix, names);
  43   if (NS_SUCCEEDED(rv)) {
  44     for (auto& name : names) {
  45       // Clearing the pref will cause it to reload, thus resetting the log level
  46       Preferences::ClearUser(name.get());
  47     }
  48   }
  49 }
  50
  51 /**
  52  * Loads the log level from the given pref and updates the corresponding
  53  * LogModule.
  54  */
  55 static void LoadPrefValue(const char* aName) {
  56   LogLevel logLevel = LogLevel::Disabled;
  57
  58   nsresult rv;
  59   int32_t prefLevel = 0;
  60   nsAutoCString prefValue;
  61
  62   if (strncmp(aName, kLoggingConfigPrefPrefix, kLoggingConfigPrefixLen) == 0) {
  63     nsAutoCString prefName(aName);
  64
  65     if (prefName.EqualsLiteral(kLoggingPrefLogFile)) {
  66       rv = Preferences::GetCString(aName, prefValue);
  67       // The pref was reset. Clear the user file.
  68       if (NS_FAILED(rv) || prefValue.IsEmpty()) {
  69         LogModule::SetLogFile(nullptr);
  70         return;
  71       }
  72
  73       // If the pref value doesn't have a PID placeholder, append it to the end.
  74       if (!strstr(prefValue.get(), MOZ_LOG_PID_TOKEN)) {
  75         prefValue.AppendLiteral(MOZ_LOG_PID_TOKEN);
  76       }
  77
  78       LogModule::SetLogFile(prefValue.BeginReading());
  79     } else if (prefName.EqualsLiteral(kLoggingPrefAddTimestamp)) {
  80       bool addTimestamp = Preferences::GetBool(aName, false);
  81       LogModule::SetAddTimestamp(addTimestamp);
  82     } else if (prefName.EqualsLiteral(kLoggingPrefSync)) {
  83       bool sync = Preferences::GetBool(aName, false);
  84       LogModule::SetIsSync(sync);
  85     }
  86     return;
  87   }
  88
  89   if (Preferences::GetInt(aName, &prefLevel) == NS_OK) {
  90     logLevel = ToLogLevel(prefLevel);
  91   } else if (Preferences::GetCString(aName, prefValue) == NS_OK) {
  92     if (prefValue.LowerCaseEqualsLiteral("error")) {
  93       logLevel = LogLevel::Error;
  94     } else if (prefValue.LowerCaseEqualsLiteral("warning")) {
  95       logLevel = LogLevel::Warning;
  96     } else if (prefValue.LowerCaseEqualsLiteral("info")) {
  97       logLevel = LogLevel::Info;
  98     } else if (prefValue.LowerCaseEqualsLiteral("debug")) {
  99       logLevel = LogLevel::Debug;
 100     } else if (prefValue.LowerCaseEqualsLiteral("verbose")) {
 101       logLevel = LogLevel::Verbose;
 102     }
 103   }
 104
 105   const char* moduleName = aName + strlen(kLoggingPrefPrefix);
 106   LogModule::Get(moduleName)->SetLevel(logLevel);
 107 }
 108
 109 static void LoadExistingPrefs() {
 110   nsIPrefBranch* root = Preferences::GetRootBranch();
 111   if (!root) {
 112     return;
 113   }
 114
 115   nsTArray<nsCString> names;
 116   nsresult rv = root->GetChildList(kLoggingPrefPrefix, names);
 117   if (NS_SUCCEEDED(rv)) {
 118     for (auto& name : names) {
 119       LoadPrefValue(name.get());
 120     }
 121   }
 122 }
 123
 124 LogModulePrefWatcher::LogModulePrefWatcher() = default;
 125
 126 void LogModulePrefWatcher::RegisterPrefWatcher() {
 127   RefPtr<LogModulePrefWatcher> prefWatcher = new LogModulePrefWatcher();
 128   Preferences::AddStrongObserver(prefWatcher, kLoggingPrefPrefix);
 129
 130   nsCOMPtr<nsIObserverService> observerService =
 131       mozilla::services::GetObserverService();
 132   if (observerService && XRE_IsParentProcess()) {
 133     observerService->AddObserver(prefWatcher,
 134                                  "browser-delayed-startup-finished", false);
 135   }
 136
 137   LoadExistingPrefs();
 138 }
 139
 140 NS_IMETHODIMP
 141 LogModulePrefWatcher::Observe(nsISupports* aSubject, const char* aTopic,
 142                               const char16_t* aData) {
 143   if (strcmp(NS_PREFBRANCH_PREFCHANGE_TOPIC_ID, aTopic) == 0) {
 144     NS_LossyConvertUTF16toASCII prefName(aData);
 145     LoadPrefValue(prefName.get());
 146   } else if (strcmp("browser-delayed-startup-finished", aTopic) == 0) {
 147     bool clear = Preferences::GetBool(kLoggingPrefClearOnStartup, true);
 148     if (clear) {
 149       ResetExistingPrefs();
 150     }
 151     nsCOMPtr<nsIObserverService> observerService =
 152         mozilla::services::GetObserverService();
 153     if (observerService) {
 154       observerService->RemoveObserver(this, "browser-delayed-startup-finished");
 155     }
 156   }
 157
 158   return NS_OK;
 159 }
 160
 161 }  // namespace mozilla