SQLite

      pBt->usableSize = usableSize;
      pBt->pageSize = pageSize;
      freeTempSpace(pBt);
      rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize,
                                   pageSize-usableSize);
      return rc;
    }
    if( (pBt->db->flags & (SQLITE_WriteSchema|SQLITE_Defensive))==0
     && nPage>nPageFile
    ){
      rc = SQLITE_CORRUPT_BKPT;
      goto page1_init_failed;
    }
    /* EVIDENCE-OF: R-28312-64704 However, the usable size is not allowed to
    ** be less than 480. In other words, if the page size is 512, then the
    ** reserved space size cannot exceed 32. */
    if( usableSize<480 ){

** unqualified name for a new schema object (table, index, view or
** trigger). All names are legal except those that begin with the string
** "sqlite_" (in upper, lower or mixed case). This portion of the namespace
** is reserved for internal use.
*/
int sqlite3CheckObjectName(Parse *pParse, const char *zName){
  if( !pParse->db->init.busy && pParse->nested==0 
          && (pParse->db->flags & (SQLITE_WriteSchema|SQLITE_Defensive))==0
          && 0==sqlite3StrNICmp(zName, "sqlite_", 7) ){
    sqlite3ErrorMsg(pParse, "object name reserved for internal use: %s", zName);
    return SQLITE_ERROR;
  }
  return SQLITE_OK;
}

  char *zErr = 0;
  const char *zSchema;
  int iDb;
  Btree *pBt;
  Pager *pPager;
  int szPage;

  if( pTab->db->flags & SQLITE_Defensive ){
    zErr = "read-only";
    goto update_fail;
  }
  if( argc==1 ){
    zErr = "cannot delete";
    goto update_fail;
  }
  pgno = sqlite3_value_int(argv[0]);
  if( (Pgno)sqlite3_value_int(argv[1])!=pgno ){
    zErr = "cannot insert";

  **      been specified.
  **
  ** In either case leave an error message in pParse and return non-zero.
  */
  if( ( IsVirtual(pTab) 
     && sqlite3GetVTable(pParse->db, pTab)->pMod->pModule->xUpdate==0 )
   || ( (pTab->tabFlags & TF_Readonly)!=0
     && (pParse->db->flags & (SQLITE_WriteSchema|SQLITE_Defensive))==0
     && pParse->nested==0 )
  ){
    sqlite3ErrorMsg(pParse, "table %s may not be modified", pTab->zName);
    return 1;
  }

#ifndef SQLITE_OMIT_VIEW

        { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
        { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
        { SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, SQLITE_LoadExtension  },
        { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE,      SQLITE_NoCkptOnClose  },
        { SQLITE_DBCONFIG_ENABLE_QPSG,           SQLITE_EnableQPSG     },
        { SQLITE_DBCONFIG_TRIGGER_EQP,           SQLITE_TriggerEQP     },
        { SQLITE_DBCONFIG_RESET_DATABASE,        SQLITE_ResetDatabase  },
        { SQLITE_DBCONFIG_DEFENSIVE,             SQLITE_Defensive      },
      };
      unsigned int i;
      rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
      for(i=0; i<ArraySize(aFlagOp); i++){
        if( aFlagOp[i].op==op ){
          int onoff = va_arg(ap, int);
          int *pRes = va_arg(ap, int*);

        { "enable_trigger",   SQLITE_DBCONFIG_ENABLE_TRIGGER         },
        { "fts3_tokenizer",   SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER  },
        { "load_extension",   SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION  },
        { "no_ckpt_on_close", SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE       },
        { "enable_qpsg",      SQLITE_DBCONFIG_ENABLE_QPSG            },
        { "trigger_eqp",      SQLITE_DBCONFIG_TRIGGER_EQP            },
        { "reset_database",   SQLITE_DBCONFIG_RESET_DATABASE         },
        { "defensive",        SQLITE_DBCONFIG_DEFENSIVE              },
    };
    int ii, v;
    open_db(p, 0);
    for(ii=0; ii<ArraySize(aDbConfig); ii++){
      if( nArg>1 && strcmp(azArg[1], aDbConfig[ii].zName)!=0 ) continue;
      if( nArg>=3 ){
        sqlite3_db_config(p->db, aDbConfig[ii].op, booleanValue(azArg[2]), 0);

** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
** </ol>
** Because resetting a database is destructive and irreversible, the
** process requires the use of this obscure API and multiple steps to help
** ensure that it does not happen by accident.
**
** <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
** <dd>The SQLITE_DBCONFIG_DEFENSIVE option actives or deactivates the
** "defensive" flag for a database connection.  When the defensive
** flag is enabled, some obscure features of SQLite are disabled in order
** to reduce the attack surface. Applications that run untrusted SQL
** can activate this flag to reduce the risk of zero-day exploits.
** <p>
** Features disabled by the defensive flag include:
** <ul>
** <li>The [PRAGMA writable_schema=ON] statement.
** <li>Writes to the [sqlite_dbpage] virtual table.
** </ul>
** New restrictions may be added in future releases.
** <p>
** To be clear: It should never be possible for hostile SQL to cause
** arbitrary memory reads, memory leaks, buffer overflows, assertion
** faults, arbitrary code execution, crashes, or other mischief, regardless
** of the value of the defensive flag.  Any occurrance of these problems
** is considered a serious bug and will be fixed promptly.  It is not
** necessary to enable the defensive flag in order to make SQLite secure
** against attack. The defensive flag merely provides an additional layer
** of defense against unknown vulnerabilities.
** </dd>
** </dl>
*/
#define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
#define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
#define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
#define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
#define SQLITE_DBCONFIG_RESET_DATABASE        1009 /* int int* */
#define SQLITE_DBCONFIG_DEFENSIVE             1010 /* int int* */
#define SQLITE_DBCONFIG_MAX                   1010 /* Largest DBCONFIG */

/*
** CAPI3REF: Enable Or Disable Extended Result Codes
** METHOD: sqlite3
**
** ^The sqlite3_extended_result_codes() routine enables or disables the
** [extended result codes] feature of SQLite. ^The extended result

#define SQLITE_CellSizeCk     0x00200000  /* Check btree cell sizes on load */
#define SQLITE_Fts3Tokenizer  0x00400000  /* Enable fts3_tokenizer(2) */
#define SQLITE_EnableQPSG     0x00800000  /* Query Planner Stability Guarantee*/
#define SQLITE_TriggerEQP     0x01000000  /* Show trigger EXPLAIN QUERY PLAN */
#define SQLITE_ResetDatabase  0x02000000  /* Reset the database */
#define SQLITE_LegacyAlter    0x04000000  /* Legacy ALTER TABLE behaviour */
#define SQLITE_NoSchemaError  0x08000000  /* Do not report schema parse errors*/
#define SQLITE_Defensive      0x10000000  /* Input SQL is likely hostile */

/* Flags used only if debugging */
#define HI(X)  ((u64)(X)<<32)
#ifdef SQLITE_DEBUG
#define SQLITE_SqlTrace       HI(0x0001)  /* Debug print SQL as it executes */
#define SQLITE_VdbeListing    HI(0x0002)  /* Debug listings of VDBE progs */
#define SQLITE_VdbeTrace      HI(0x0004)  /* True to trace VDBE execution */