在一次需求的实现过程中需要在remcovery模式下,在/cache/recovery/目录下创建一个日志文件用于记录相关的日志信息,以便于在开机后读取这些日志信息,再根据日志信息做出相应的处理,但是奇怪的是每当开机完成该文件不被系统自动删除,而系统中原有的日志文件(如升级log—last_log_r)等却依然保留,因此在全局中搜索关键字”/cache/recovery/“发现了这其中的原因。
也就是说系统会在系统启动完成后删除/cache/recovery/目录下不是以”last_”为前缀的文件,那么具体是如何实现的呢,我们一起来看一下。
首先在framework层有一个BootReceiver这样一个类,用于处理系统启动完成后的善后工作,例如删除旧的无关的日志信息等。
第一步:在framework/base/core/res下的清单文件AndroidManifest.xml中注册广播接收器BootReceiver,用于接收系统启动完成的广播如下:
- <receiver android:name=“com.android.server.BootReceiver”
- android:primaryUserOnly=“true”>
- <intent-filter>
- <action android:name=“android.intent.action.BOOT_COMPLETED” />
- </intent-filter>
- </receiver>
<receiver android:name="com.android.server.BootReceiver"
android:primaryUserOnly="true">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
第二步:当系统启动完成后,这个广播接收器会接收到系统启动完成的广播之后在onReceive下执行logBootEvents函数,并执行RecoverySystem下的handleAftermath()函数,最终删除在/cache/recovery下不是以last_为前缀的文件。具体函数如下:
- /**
- * Called after booting to process and remove recovery-related files.
- * @return the log file from recovery, or null if none was found.
- *
- * @hide
- */
- public static String handleAftermath() {
- // Record the tail of the LOG_FILE
- Log.d(TAG,”Entering the handleAftermath method”);
- String log = null;
- try {
- log = FileUtils.readTextFile(LOG_FILE, -LOG_FILE_MAX_LENGTH, ”…\n”);
- } catch (FileNotFoundException e) {
- Log.i(TAG, ”No recovery log file”);
- } catch (IOException e) {
- Log.e(TAG, ”Error reading recovery log”, e);
- }
- // Delete everything in RECOVERY_DIR except those beginning
- // with LAST_PREFIX
- String[] names = RECOVERY_DIR.list();
- for (int i = 0; names != null && i < names.length; i++) {
- if (names[i].startsWith(LAST_PREFIX)) continue;
- File f = new File(RECOVERY_DIR, names[i]);
- if (!f.delete()) {
- Log.e(TAG, ”Can’t delete: ” + f);
- } else {
- Log.i(TAG, ”Deleted: ” + f);
- }
- }
- return log;
- }
/**
* Called after booting to process and remove recovery-related files.
* @return the log file from recovery, or null if none was found.
*
* @hide
*/
public static String handleAftermath() {
// Record the tail of the LOG_FILE
Log.d(TAG,"Entering the handleAftermath method");
String log = null;
try {
log = FileUtils.readTextFile(LOG_FILE, -LOG_FILE_MAX_LENGTH, "...\n");
} catch (FileNotFoundException e) {
Log.i(TAG, "No recovery log file");
} catch (IOException e) {
Log.e(TAG, "Error reading recovery log", e);
}
// Delete everything in RECOVERY_DIR except those beginning
// with LAST_PREFIX
String[] names = RECOVERY_DIR.list();
for (int i = 0; names != null && i < names.length; i++) {
if (names[i].startsWith(LAST_PREFIX)) continue;
File f = new File(RECOVERY_DIR, names[i]);
if (!f.delete()) {
Log.e(TAG, "Can't delete: " + f);
} else {
Log.i(TAG, "Deleted: " + f);
}
}
return log;
}
注:如果我们需要在/cache/recovery/目录下保存文件,我们可以以”last_”为前缀进行命名也可以在RecoverySystem中修改相关的逻辑。
在一次需求的实现过程中需要在remcovery模式下,在/cache/recovery/目录下创建一个日志文件用于记录相关的日志信息,以便于在开机后读取这些日志信息,再根据日志信息做出相应的处理,但是奇怪的是每当开机完成该文件不被系统自动删除,而系统中原有的日志文件(如升级log—last_log_r)等却依然保留,因此在全局中搜索关键字”/cache/recovery/“发现了这其中的原因。
也就是说系统会在系统启动完成后删除/cache/recovery/目录下不是以”last_”为前缀的文件,那么具体是如何实现的呢,我们一起来看一下。
首先在framework层有一个BootReceiver这样一个类,用于处理系统启动完成后的善后工作,例如删除旧的无关的日志信息等。
第一步:在framework/base/core/res下的清单文件AndroidManifest.xml中注册广播接收器BootReceiver,用于接收系统启动完成的广播如下:
- <receiver android:name=“com.android.server.BootReceiver”
- android:primaryUserOnly=“true”>
- <intent-filter>
- <action android:name=“android.intent.action.BOOT_COMPLETED” />
- </intent-filter>
- </receiver>
<receiver android:name="com.android.server.BootReceiver"
android:primaryUserOnly="true">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
第二步:当系统启动完成后,这个广播接收器会接收到系统启动完成的广播之后在onReceive下执行logBootEvents函数,并执行RecoverySystem下的handleAftermath()函数,最终删除在/cache/recovery下不是以last_为前缀的文件。具体函数如下:
- /**
- * Called after booting to process and remove recovery-related files.
- * @return the log file from recovery, or null if none was found.
- *
- * @hide
- */
- public static String handleAftermath() {
- // Record the tail of the LOG_FILE
- Log.d(TAG,”Entering the handleAftermath method”);
- String log = null;
- try {
- log = FileUtils.readTextFile(LOG_FILE, -LOG_FILE_MAX_LENGTH, ”…\n”);
- } catch (FileNotFoundException e) {
- Log.i(TAG, ”No recovery log file”);
- } catch (IOException e) {
- Log.e(TAG, ”Error reading recovery log”, e);
- }
- // Delete everything in RECOVERY_DIR except those beginning
- // with LAST_PREFIX
- String[] names = RECOVERY_DIR.list();
- for (int i = 0; names != null && i < names.length; i++) {
- if (names[i].startsWith(LAST_PREFIX)) continue;
- File f = new File(RECOVERY_DIR, names[i]);
- if (!f.delete()) {
- Log.e(TAG, ”Can’t delete: ” + f);
- } else {
- Log.i(TAG, ”Deleted: ” + f);
- }
- }
- return log;
- }
/**
* Called after booting to process and remove recovery-related files.
* @return the log file from recovery, or null if none was found.
*
* @hide
*/
public static String handleAftermath() {
// Record the tail of the LOG_FILE
Log.d(TAG,"Entering the handleAftermath method");
String log = null;
try {
log = FileUtils.readTextFile(LOG_FILE, -LOG_FILE_MAX_LENGTH, "...\n");
} catch (FileNotFoundException e) {
Log.i(TAG, "No recovery log file");
} catch (IOException e) {
Log.e(TAG, "Error reading recovery log", e);
}
// Delete everything in RECOVERY_DIR except those beginning
// with LAST_PREFIX
String[] names = RECOVERY_DIR.list();
for (int i = 0; names != null && i < names.length; i++) {
if (names[i].startsWith(LAST_PREFIX)) continue;
File f = new File(RECOVERY_DIR, names[i]);
if (!f.delete()) {
Log.e(TAG, "Can't delete: " + f);
} else {
Log.i(TAG, "Deleted: " + f);
}
}
return log;
}
注:如果我们需要在/cache/recovery/目录下保存文件,我们可以以”last_”为前缀进行命名也可以在RecoverySystem中修改相关的逻辑。