• Android 9.0 SQLiteCantOpenDatabaseException SQLITE_CANTOPEN(不支持WAL模式)源码分析定位

    最近一直忙着处理降低crash率，在Bugly上最新版本中统计到的一个数据库有关的crash:

    # pool-20-thread-1(323)
android.database.sqlite.SQLiteCantOpenDatabaseException
unable to open database file (Sqlite code 14 SQLITE_CANTOPEN), (OS error - 2:No such file or directory)

android.database.sqlite.SQLiteConnection.nativeExecuteForLong(Native Method)
android.database.sqlite.SQLiteConnection.executeForLong(SQLiteConnection.java:657)
android.database.sqlite.SQLiteSession.executeForLong(SQLiteSession.java:667)
android.database.sqlite.SQLiteStatement.simpleQueryForLong(SQLiteStatement.java:107)
android.database.DatabaseUtils.longForQuery(DatabaseUtils.java:842)
android.database.DatabaseUtils.longForQuery(DatabaseUtils.java:830)
android.database.sqlite.SQLiteDatabase.getVersion(SQLiteDatabase.java:1036)
android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:390)
android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper.java:337)
com.meta.android.mpg.mix.sG4DaaDs.a4Dgsas.a4Dgsas(Unknown Source:3)
com.meta.android.mpg.mix.gG4Gas.fa$fa.run(Unknown Source:4)
java.util.concurrent.ThreadPoolExecutor.processTask(ThreadPoolExecutor.java:1187)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1152)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
java.lang.Thread.run(Thread.java:784)

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    发生的机型统计如下：
    在这里插入图片描述

    1.源码定位分析

    1.1借助系统日志来辅助定位

    查看bugly 捕捉的有效log:

    08-23 17:13:28.790 5668 5860 E SQLiteLog: (14) cannot open file at line 36906 of [68b898381a]
4708-23 17:13:28.790 5668 5860 E SQLiteLog: (14) os_unix.c:36906: (2) open(/data/data/com.tools.growth.yhxy/virtual/data/user/0/com.minitech.miniworld.meta/databases/MpgSdk.db-wal) -
4808-23 17:13:28.791 5668 5860 E SQLiteLog: (14) unable to open database file// 有效日志
4908-23 17:13:28.791 5668 5860 E SQLiteDatabase: Failed to open database  '/data/data/com.tools.growth.yhxy/virtual/data/user/0/com.minitech.miniworld.meta/databases/MpgSdk.db'.
5008-23 17:13:28.791 5668 5860 E SQLiteDatabase: android.database.sqlite.SQLiteCantOpenDatabaseException: unable to open database file (Sqlite code 14 SQLITE_CANTOPEN): , while compiling: PRAGMA journal_mode, (OS error - 2:No such file or directory) 
5108-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
5208-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:948)
5308-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteConnection.executeForString(SQLiteConnection.java:693)
5408-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteConnection.setJournalMode(SQLiteConnection.java:378)
5508-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteConnection.setWalModeFromConfiguration(SQLiteConnection.java:327)
5608-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:232)
5708-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:210)
5808-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:552)
5908-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:213)
6008-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:202)
6108-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:958)
6208-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:942)
6308-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:816)
6408-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:806)
6508-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:370)
6608-23 17:13:28.791 5668 5860 E SQLiteDatabase: at android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper.java:337)
6708-23 17:13:28.791 5668 5860 E SQLiteDatabase: at com.meta.android.mpg.mix.sG4DaaDs.a4Dgsas.a4Dgsas(Unknown Source:3)
6808-23 17:13:28.791 5668 5860 E SQLiteDatabase: at com.meta.android.mpg.mix.gG4Gas.fa$fa.run(Unknown Source:4)
6908-23 17:13:28.791 5668 5860 E SQLiteDatabase: at java.util.concurrent.ThreadPoolExecutor.processTask(ThreadPoolExecutor.java:1187)
7008-23 17:13:28.791 5668 5860 E SQLiteDatabase: at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1152)
7108-23 17:13:28.791 5668 5860 E SQLiteDatabase: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)

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    当Bugly中的当前crash记录上报没有日志时，可以多查看几条记录，日志是一个很好加速定位问题的辅助手段。

    1.2查看源码，锁定报错点

    本篇源码基于android 9.0

    /frameworks/base/core/java/android/database/sqlite/SQLiteConnection.java

        private PreparedStatement acquirePreparedStatement(String sql) {
        PreparedStatement statement = mPreparedStatementCache.get(sql);
        //...
        final long statementPtr = nativePrepareStatement(mConnectionPtr, sql);
        //...
        return statement;
    }
	private static native long nativePrepareStatement(long connectionPtr, String sql);

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    接下来看下jni 层的调用。

    /frameworks/base/core/jni/android_database_SQLiteConnection.cpp

    static jlong nativePrepareStatement(JNIEnv* env, jclass clazz, jlong connectionPtr,
        jstring sqlString) {
    SQLiteConnection* connection = reinterpret_cast<SQLiteConnection*>(connectionPtr);

    jsize sqlLength = env->GetStringLength(sqlString);
    const jchar* sql = env->GetStringCritical(sqlString, NULL);
    sqlite3_stmt* statement;
    int err = sqlite3_prepare16_v2(connection->db,
            sql, sqlLength * sizeof(jchar), &statement, NULL);
    env->ReleaseStringCritical(sqlString, sql);

    if (err != SQLITE_OK) {
        //构建异常信息
        const char *query = env->GetStringUTFChars(sqlString, NULL);
        char *message = (char*) malloc(strlen(query) + 50);
        if (message) {
            strcpy(message, ", while compiling: "); // less than 50 chars
            strcat(message, query);
        }
        env->ReleaseStringUTFChars(sqlString, query);
		//抛出异常
        throw_sqlite3_exception(env, connection->db, message);
        free(message);
        return 0;
    }
    return reinterpret_cast<jlong>(statement);
}

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    这里刚好和日志中的while compiling: PRAGMA journal_mode 匹配,说明 调用sqlite3_prepare16_v2 返回失败结果。

    接着继续, 查看sqlite3_prepare16_v2()：

    /external/sqlite/dist/orig/sqlite3.c

    SQLITE_API int sqlite3_prepare16_v2(
  sqlite3 *db,              /* Database handle. */
  const void *zSql,         /* UTF-16 encoded SQL statement. */
  int nBytes,               /* Length of zSql in bytes. */
  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
  const void **pzTail       /* OUT: End of parsed string */
){
  int rc;
  rc = sqlite3Prepare16(db,zSql,nBytes,SQLITE_PREPARE_SAVESQL,ppStmt,pzTail);
  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
  return rc;
}

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    因SQLite的源码太过于庞大，只能考虑逆推方式，先根据报错日志，检索关键位置。

    根据unable to open database file匹配到SQLITE_CANTOPEN 字段。

    SQLITE_PRIVATE const char *sqlite3ErrStr(int rc){
  static const char* const aMsg[] = {
   /* SQLITE_CANTOPEN    */ "unable to open database file",
  }
  //... 
}

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    根据cannot open file at和SQLITE_CANTOPEN 匹配到sqlite3CantopenError(),用于报错时，拼接打印报错信息：

    接下来看下，sqlite3CantopenError():

    #define SQLITE_CANTOPEN_BKPT sqlite3CantopenError(__LINE__)

SQLITE_PRIVATE int sqlite3CantopenError(int lineno){
  testcase( sqlite3GlobalConfig.xLog!=0 );
  return sqlite3ReportError(SQLITE_CANTOPEN, lineno, "cannot open file"); // 对应日志：(14) cannot open file at line 36906 of [68b898381a]
}

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    全局检索SQLITE_CANTOPEN 关键字，耗费脑细胞的逐步分析调用链：sqlite3Prepare16()->省略部分流程->sqlite3BtreeBeginTrans()->lockBtree()->sqlite3PagerOpenWal()。

    接下来看下，sqlite3BtreeBeginTrans():

    SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
  
  //....
  do {
  
	//循环检查，直到lockBtree返回相应状态
    while( pBt->pPage1==0 && SQLITE_OK==(rc = lockBtree(pBt)) );
    if( rc==SQLITE_OK && wrflag ){
      if( (pBt->btsFlags & BTS_READ_ONLY)!=0 ){
        rc = SQLITE_READONLY;
      }else{
        rc = sqlite3PagerBegin(pBt->pPager,wrflag>1,sqlite3TempInMemory(p->db));
        if( rc==SQLITE_OK ){
          rc = newDatabase(pBt);
        }
      }
    }
    if( rc!=SQLITE_OK ){
      unlockBtreeIfUnused(pBt);
    }
  }while( (rc&0xFF)==SQLITE_BUSY && pBt->inTransaction==TRANS_NONE &&
          btreeInvokeBusyHandler(pBt) )

  return rc;
}

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    接着继续查看,lockBtree():

    static int lockBtree(BtShared *pBt){
  int rc;              /* Result code from subfunctions */
  MemPage *pPage1;     /* Page 1 of the database file */
  int nPage;           /* Number of pages in the database */
  int nPageFile = 0;   /* Number of pages in the database file */
  int nPageHeader;     /* Number of pages in the database according to hdr */

  //先获取一个share lock
  rc = sqlite3PagerSharedLock(pBt->pPager);
  if( rc!=SQLITE_OK ) return rc;
  
  //...
  
  //当write version 是2，数据库应该使用wal 模式。若是检查到log文件没有被打开，则进行打开。
    if( page1[19]==2 && (pBt->btsFlags & BTS_NO_WAL)==0 ){
      int isOpen = 0;
      rc = sqlite3PagerOpenWal(pBt->pPager, &isOpen);
      if( rc!=SQLITE_OK ){
	    //若是打开失败,则进行释放资源操作
        goto page1_init_failed;
      }else{
        setDefaultSyncFlag(pBt, SQLITE_DEFAULT_WAL_SYNCHRONOUS+1);
        if( isOpen==0 ){
          releasePageOne(pPage1);
          return SQLITE_OK;
        }
      }
	  // 若是打开正常，则返回 SQLITE_NOTADB
      rc = SQLITE_NOTADB;
    }else{
      setDefaultSyncFlag(pBt, SQLITE_DEFAULT_SYNCHRONOUS+1);
    }
   //....
   
  page1_init_failed:
  releasePageOne(pPage1);
  pBt->pPage1 = 0;
  return rc;
}

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    先来看下，sqlite3PagerSharedLock():

    SQLITE_PRIVATE int sqlite3PagerSharedLock(Pager *pPager){
  int rc = SQLITE_OK;                /* Return code */


  if( !pagerUseWal(pPager) && pPager->eState==PAGER_OPEN ){

    // 获取到shared lock 
    rc = pager_wait_on_lock(pPager, SHARED_LOCK);
    //...

  }
 
  return rc;
}

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    接下来看下,sqlite3PagerOpenWal():

    SQLITE_PRIVATE int sqlite3PagerOpenWal(
  Pager *pPager,                  /* Pager object */
  int *pbOpen                     /* OUT: Set to true if call is a no-op */
){
  int rc = SQLITE_OK;             /* Return code */

  assert( assert_pager_state(pPager) );
  assert( pPager->eState==PAGER_OPEN   || pbOpen );
  assert( pPager->eState==PAGER_READER || !pbOpen );
  assert( pbOpen==0 || *pbOpen==0 );
  assert( pbOpen!=0 || (!pPager->tempFile && !pPager->pWal) );

  if( !pPager->tempFile && !pPager->pWal ){
  
    // 关键代码： 若是不支持Write-Ahead-Logging(即)模式, 则返回SQLITE_CANTOPEN。
    if( !sqlite3PagerWalSupported(pPager) ) return SQLITE_CANTOPEN;

    /* Close any rollback journal previously open */
    sqlite3OsClose(pPager->jfd);

    rc = pagerOpenWal(pPager);
    if( rc==SQLITE_OK ){ // 若是支持Write-Ahead-Logging 模式，则标记打开模式和状态
      pPager->journalMode = PAGER_JOURNALMODE_WAL;
      pPager->eState = PAGER_OPEN;
    }
  }else{
    *pbOpen = 1;
  }

  return rc;
}

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    通过一些列的分析，推断是因数据库不支持Write-Ahead-Logging 模式导致的，因此考虑禁止使用该模式，可以处理该问题。

    2.解决方案

    2.1 Android 9及其以上数据库的WAL模式：

    Android 9 引入了 SQLiteDatabase 的一种特殊模式，称为“兼容性 WAL（预写日志记录）”，它允许数据库使用 journal_mode=WAL，同时保留每个数据库最多创建一个连接的行为.

    更多有信息,请阅读应用的兼容性 WAL（预写日志记录）。

    2.2禁止启用wal 模式的解决方案：

    https://stackoverflow.com/questions/53659206/disabling-sqlite-write-ahead-logging-in-android-pie

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  • 原文地址：https://blog.csdn.net/hexingen/article/details/126538093