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Overview
Comment:Handle some boundary cases in memdb associated with OOM faults.
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SHA3-256: b58ca4cb0c921e81efad527c80b220be120263cfdb04528ae26ecf8b8f66f44a
User & Date: drh 2018-03-06 20:54:27.966
Context
2018-03-06
21:43
Improved documentation for sqlite3_serialize() and sqlite3_deserialize(). Change the name of the compile-time option to enable these interfaces from SQLITE_ENABLE_MEMDB to SQLITE_ENABLE_DESERIALIZE. (check-in: f07e97aed4 user: drh tags: memdb)
20:54
Handle some boundary cases in memdb associated with OOM faults. (check-in: b58ca4cb0c user: drh tags: memdb)
19:14
Simplifications to the memdb VFS. (check-in: 6c3f723a68 user: drh tags: memdb)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/attach.c.
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  if( REOPEN_AS_MEMDB(db) ){
    /* This is not a real ATTACH.  Instead, this routine is being called
    ** from sqlite3_deserialize() to close database db->init.iDb and
    ** reopen it as a MemDB */
    pVfs = sqlite3_vfs_find("memdb");
    if( pVfs==0 ) return;
    pNew = &db->aDb[db->init.iDb];
    sqlite3BtreeClose(pNew->pBt);
    pNew->pBt = 0;
    pNew->pSchema = 0;
    rc = sqlite3BtreeOpen(pVfs, "x", db, &pNew->pBt, 0, SQLITE_OPEN_MAIN_DB);
  }else{
    /* This is a real ATTACH
    **
    ** Check for the following errors:








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  if( REOPEN_AS_MEMDB(db) ){
    /* This is not a real ATTACH.  Instead, this routine is being called
    ** from sqlite3_deserialize() to close database db->init.iDb and
    ** reopen it as a MemDB */
    pVfs = sqlite3_vfs_find("memdb");
    if( pVfs==0 ) return;
    pNew = &db->aDb[db->init.iDb];
    if( pNew->pBt ) sqlite3BtreeClose(pNew->pBt);
    pNew->pBt = 0;
    pNew->pSchema = 0;
    rc = sqlite3BtreeOpen(pVfs, "x", db, &pNew->pBt, 0, SQLITE_OPEN_MAIN_DB);
  }else{
    /* This is a real ATTACH
    **
    ** Check for the following errors:
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  ** way we found it.
  */
  if( rc==SQLITE_OK ){
    sqlite3BtreeEnterAll(db);
    db->init.iDb = 0;
    rc = sqlite3Init(db, &zErrDyn);
    sqlite3BtreeLeaveAll(db);

  }
#ifdef SQLITE_USER_AUTHENTICATION
  if( rc==SQLITE_OK ){
    u8 newAuth = 0;
    rc = sqlite3UserAuthCheckLogin(db, zName, &newAuth);
    if( newAuth<db->auth.authLevel ){
      rc = SQLITE_AUTH_USER;
    }
  }
#endif

  if( rc && !REOPEN_AS_MEMDB(db) ){
    int iDb = db->nDb - 1;
    assert( iDb>=2 );
    if( db->aDb[iDb].pBt ){
      sqlite3BtreeClose(db->aDb[iDb].pBt);
      db->aDb[iDb].pBt = 0;
      db->aDb[iDb].pSchema = 0;
    }
    sqlite3ResetAllSchemasOfConnection(db);
    db->nDb = iDb;
    if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
      sqlite3OomFault(db);
      sqlite3DbFree(db, zErrDyn);
      zErrDyn = sqlite3MPrintf(db, "out of memory");
    }else if( zErrDyn==0 ){
      zErrDyn = sqlite3MPrintf(db, "unable to open database: %s", zFile);

    }
    goto attach_error;
  }
  
  return;

attach_error:








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  ** way we found it.
  */
  if( rc==SQLITE_OK ){
    sqlite3BtreeEnterAll(db);
    db->init.iDb = 0;
    rc = sqlite3Init(db, &zErrDyn);
    sqlite3BtreeLeaveAll(db);
    assert( zErrDyn==0 || rc!=SQLITE_OK );
  }
#ifdef SQLITE_USER_AUTHENTICATION
  if( rc==SQLITE_OK ){
    u8 newAuth = 0;
    rc = sqlite3UserAuthCheckLogin(db, zName, &newAuth);
    if( newAuth<db->auth.authLevel ){
      rc = SQLITE_AUTH_USER;
    }
  }
#endif
  if( rc ){
    if( !REOPEN_AS_MEMDB(db) ){
      int iDb = db->nDb - 1;
      assert( iDb>=2 );
      if( db->aDb[iDb].pBt ){
        sqlite3BtreeClose(db->aDb[iDb].pBt);
        db->aDb[iDb].pBt = 0;
        db->aDb[iDb].pSchema = 0;
      }
      sqlite3ResetAllSchemasOfConnection(db);
      db->nDb = iDb;
      if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
        sqlite3OomFault(db);
        sqlite3DbFree(db, zErrDyn);
        zErrDyn = sqlite3MPrintf(db, "out of memory");
      }else if( zErrDyn==0 ){
        zErrDyn = sqlite3MPrintf(db, "unable to open database: %s", zFile);
      }
    }
    goto attach_error;
  }
  
  return;

attach_error:
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Changes to src/memdb.c.
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  pBt = db->aDb[iDb].pBt;
  if( pBt==0 ) return 0;
  szPage = sqlite3BtreeGetPageSize(pBt);
  zSql = sqlite3_mprintf("PRAGMA \"%w\".page_count", zSchema);
  rc = zSql ? sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0) : SQLITE_NOMEM;
  sqlite3_free(zSql);
  if( rc ) return 0;
  sqlite3_step(pStmt);



  sz = sqlite3_column_int64(pStmt, 0)*szPage;
  if( piSize ) *piSize = sz;
  if( mFlags & SQLITE_SERIALIZE_NOCOPY ){
    pOut = 0;
  }else{
    pOut = sqlite3_malloc64( sz );
    if( pOut ){
      int nPage = sqlite3_column_int(pStmt, 0);
      Pager *pPager = sqlite3BtreePager(pBt);
      int pgno;
      for(pgno=1; pgno<=nPage; pgno++){
        DbPage *pPage = 0;
        unsigned char *pTo = pOut + szPage*(sqlite3_int64)(pgno-1);
        rc = sqlite3PagerGet(pPager, pgno, (DbPage**)&pPage, 0);
        if( rc==SQLITE_OK ){
          memcpy(pTo, sqlite3PagerGetData(pPage), szPage);
        }else{
          memset(pTo, 0, szPage);
        }
        sqlite3PagerUnref(pPage);       

      }
    }
  }
  sqlite3_finalize(pStmt);
  return pOut;
}









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  pBt = db->aDb[iDb].pBt;
  if( pBt==0 ) return 0;
  szPage = sqlite3BtreeGetPageSize(pBt);
  zSql = sqlite3_mprintf("PRAGMA \"%w\".page_count", zSchema);
  rc = zSql ? sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0) : SQLITE_NOMEM;
  sqlite3_free(zSql);
  if( rc ) return 0;
  rc = sqlite3_step(pStmt);
  if( rc!=SQLITE_ROW ){
    pOut = 0;
  }else{
    sz = sqlite3_column_int64(pStmt, 0)*szPage;
    if( piSize ) *piSize = sz;
    if( mFlags & SQLITE_SERIALIZE_NOCOPY ){
      pOut = 0;
    }else{
      pOut = sqlite3_malloc64( sz );
      if( pOut ){
        int nPage = sqlite3_column_int(pStmt, 0);
        Pager *pPager = sqlite3BtreePager(pBt);
        int pgno;
        for(pgno=1; pgno<=nPage; pgno++){
          DbPage *pPage = 0;
          unsigned char *pTo = pOut + szPage*(sqlite3_int64)(pgno-1);
          rc = sqlite3PagerGet(pPager, pgno, (DbPage**)&pPage, 0);
          if( rc==SQLITE_OK ){
            memcpy(pTo, sqlite3PagerGetData(pPage), szPage);
          }else{
            memset(pTo, 0, szPage);
          }
          sqlite3PagerUnref(pPage);       
        }
      }
    }
  }
  sqlite3_finalize(pStmt);
  return pOut;
}
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  rc = sqlite3_step(pStmt);
  db->init.reopenMemdb = 0;
  if( rc!=SQLITE_DONE ){
    rc = SQLITE_ERROR;
    goto end_deserialize;
  }
  p = memdbFromDbSchema(db, zSchema);
  /* The memdbFromDbSchema() call can only fail if zSchema is not
  ** a valid schema name or if the schema is not a memdb schema.  But
  ** neither of those things can be true here, so failure is not possible */
  assert( p!=0 );
  p->aData = pData;
  p->sz = szDb;
  p->szMax = szBuf;
  p->mFlags = mFlags;
  rc = SQLITE_OK;


end_deserialize:
  sqlite3_finalize(pStmt);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

/* 








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  rc = sqlite3_step(pStmt);
  db->init.reopenMemdb = 0;
  if( rc!=SQLITE_DONE ){
    rc = SQLITE_ERROR;
    goto end_deserialize;
  }
  p = memdbFromDbSchema(db, zSchema);
  if( p==0 ){
    rc = SQLITE_ERROR;

  }else{
    p->aData = pData;
    p->sz = szDb;
    p->szMax = szBuf;
    p->mFlags = mFlags;
    rc = SQLITE_OK;
  }

end_deserialize:
  sqlite3_finalize(pStmt);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

/*
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