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Overview
Comment:Take care not to leave a zombie attached database if the attachment fails due to an encoding mismatch. Update attach logic to always use dynamically allocated error message strings. (CVS 6573)
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SHA1: a6cb4002ada311b56fa2b7430b98b9a0fa698a01
User & Date: drh 2009-04-30 05:19:04
Context
2009-04-30
05:40
Fix a memory leak introduced in the previous check-in. (CVS 6574) check-in: f082bf36 user: drh tags: trunk
05:19
Take care not to leave a zombie attached database if the attachment fails due to an encoding mismatch. Update attach logic to always use dynamically allocated error message strings. (CVS 6573) check-in: a6cb4002 user: drh tags: trunk
01:22
Remove always-true tests from attach.c. In btree.c, always test the return from sqlite3PagerSetPagesize() since it might return SQLITE_NOMEM. (CVS 6572) check-in: 8bf60b24 user: drh tags: trunk
Changes
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Changes to src/attach.c.

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**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the ATTACH and DETACH commands.
**
** $Id: attach.c,v 1.85 2009/04/30 01:22:41 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_ATTACH
/*
** Resolve an expression that was part of an ATTACH or DETACH statement. This
** is slightly different from resolving a normal SQL expression, because simple
................................................................................
  int i;
  int rc = 0;
  sqlite3 *db = sqlite3_context_db_handle(context);
  const char *zName;
  const char *zFile;
  Db *aNew;
  char *zErrDyn = 0;
  char zErr[128];

  UNUSED_PARAMETER(NotUsed);

  zFile = (const char *)sqlite3_value_text(argv[0]);
  zName = (const char *)sqlite3_value_text(argv[1]);
  if( zFile==0 ) zFile = "";
  if( zName==0 ) zName = "";
................................................................................
  /* Check for the following errors:
  **
  **     * Too many attached databases,
  **     * Transaction currently open
  **     * Specified database name already being used.
  */
  if( db->nDb>=db->aLimit[SQLITE_LIMIT_ATTACHED]+2 ){
    sqlite3_snprintf(
      sizeof(zErr), zErr, "too many attached databases - max %d", 
      db->aLimit[SQLITE_LIMIT_ATTACHED]
    );
    goto attach_error;
  }
  if( !db->autoCommit ){
    sqlite3_snprintf(sizeof(zErr), zErr,
                     "cannot ATTACH database within transaction");
    goto attach_error;
  }
  for(i=0; i<db->nDb; i++){
    char *z = db->aDb[i].zName;
    assert( z && zName );
    if( sqlite3StrICmp(z, zName)==0 ){
      sqlite3_snprintf(sizeof(zErr), zErr, 
                       "database %s is already in use", zName);
      goto attach_error;
    }
  }

  /* Allocate the new entry in the db->aDb[] array and initialise the schema
  ** hash tables.
  */
................................................................................
                           &aNew->pBt);
  if( rc==SQLITE_OK ){
    Pager *pPager;
    aNew->pSchema = sqlite3SchemaGet(db, aNew->pBt);
    if( !aNew->pSchema ){
      rc = SQLITE_NOMEM;
    }else if( aNew->pSchema->file_format && aNew->pSchema->enc!=ENC(db) ){
      sqlite3_snprintf(sizeof(zErr), zErr, 
        "attached databases must use the same text encoding as main database");
      goto attach_error;
    }
    pPager = sqlite3BtreePager(aNew->pBt);
    sqlite3PagerLockingMode(pPager, db->dfltLockMode);
    sqlite3PagerJournalMode(pPager, db->dfltJournalMode);
  }
  aNew->zName = sqlite3DbStrDup(db, zName);
  aNew->safety_level = 3;
................................................................................
      db->aDb[iDb].pBt = 0;
      db->aDb[iDb].pSchema = 0;
    }
    sqlite3ResetInternalSchema(db, 0);
    db->nDb = iDb;
    if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
      db->mallocFailed = 1;
      sqlite3_snprintf(sizeof(zErr),zErr, "out of memory");
    }else{
      sqlite3_snprintf(sizeof(zErr),zErr, "unable to open database: %s", zFile);
    }
    goto attach_error;
  }
  
  return;

attach_error:
  /* Return an error if we get here */
  if( zErrDyn ){
    sqlite3_result_error(context, zErrDyn, -1);
    sqlite3DbFree(db, zErrDyn);
  }else{
    zErr[sizeof(zErr)-1] = 0;
    sqlite3_result_error(context, zErr, -1);
  }
  if( rc ) sqlite3_result_error_code(context, rc);
}

/*
** An SQL user-function registered to do the work of an DETACH statement. The
** three arguments to the function come directly from a detach statement:
................................................................................
  Parse *pParse,      /* Error messages will be written here */
  int iDb,            /* This is the database that must be used */
  const char *zType,  /* "view", "trigger", or "index" */
  const Token *pName  /* Name of the view, trigger, or index */
){
  sqlite3 *db;

  if( iDb<0 || iDb==1 ) return 0;
  db = pParse->db;
  assert( db->nDb>iDb );
  pFix->pParse = pParse;
  pFix->zDb = db->aDb[iDb].zName;
  pFix->zType = zType;
  pFix->pName = pName;
  return 1;
................................................................................
  DbFixer *pFix,       /* Context of the fixation */
  SrcList *pList       /* The Source list to check and modify */
){
  int i;
  const char *zDb;
  struct SrcList_item *pItem;

  if( pList==0 ) return 0;
  zDb = pFix->zDb;
  for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
    if( pItem->zDatabase==0 ){
      pItem->zDatabase = sqlite3DbStrDup(pFix->pParse->db, zDb);
    }else if( sqlite3StrICmp(pItem->zDatabase,zDb)!=0 ){
      sqlite3ErrorMsg(pFix->pParse,
         "%s %T cannot reference objects in database %s",







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**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the ATTACH and DETACH commands.
**
** $Id: attach.c,v 1.86 2009/04/30 05:19:04 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_ATTACH
/*
** Resolve an expression that was part of an ATTACH or DETACH statement. This
** is slightly different from resolving a normal SQL expression, because simple
................................................................................
  int i;
  int rc = 0;
  sqlite3 *db = sqlite3_context_db_handle(context);
  const char *zName;
  const char *zFile;
  Db *aNew;
  char *zErrDyn = 0;


  UNUSED_PARAMETER(NotUsed);

  zFile = (const char *)sqlite3_value_text(argv[0]);
  zName = (const char *)sqlite3_value_text(argv[1]);
  if( zFile==0 ) zFile = "";
  if( zName==0 ) zName = "";
................................................................................
  /* Check for the following errors:
  **
  **     * Too many attached databases,
  **     * Transaction currently open
  **     * Specified database name already being used.
  */
  if( db->nDb>=db->aLimit[SQLITE_LIMIT_ATTACHED]+2 ){

    zErrDyn = sqlite3MPrintf(db, "too many attached databases - max %d", 
      db->aLimit[SQLITE_LIMIT_ATTACHED]
    );
    goto attach_error;
  }
  if( !db->autoCommit ){

    zErrDyn = sqlite3MPrintf(db, "cannot ATTACH database within transaction");
    goto attach_error;
  }
  for(i=0; i<db->nDb; i++){
    char *z = db->aDb[i].zName;
    assert( z && zName );
    if( sqlite3StrICmp(z, zName)==0 ){

      zErrDyn = sqlite3MPrintf(db, "database %s is already in use", zName);
      goto attach_error;
    }
  }

  /* Allocate the new entry in the db->aDb[] array and initialise the schema
  ** hash tables.
  */
................................................................................
                           &aNew->pBt);
  if( rc==SQLITE_OK ){
    Pager *pPager;
    aNew->pSchema = sqlite3SchemaGet(db, aNew->pBt);
    if( !aNew->pSchema ){
      rc = SQLITE_NOMEM;
    }else if( aNew->pSchema->file_format && aNew->pSchema->enc!=ENC(db) ){
      zErrDyn = sqlite3MPrintf(db, 
        "attached databases must use the same text encoding as main database");
      rc = SQLITE_ERROR;
    }
    pPager = sqlite3BtreePager(aNew->pBt);
    sqlite3PagerLockingMode(pPager, db->dfltLockMode);
    sqlite3PagerJournalMode(pPager, db->dfltJournalMode);
  }
  aNew->zName = sqlite3DbStrDup(db, zName);
  aNew->safety_level = 3;
................................................................................
      db->aDb[iDb].pBt = 0;
      db->aDb[iDb].pSchema = 0;
    }
    sqlite3ResetInternalSchema(db, 0);
    db->nDb = iDb;
    if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
      db->mallocFailed = 1;
      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:
  /* Return an error if we get here */
  if( zErrDyn ){
    sqlite3_result_error(context, zErrDyn, -1);
    sqlite3DbFree(db, zErrDyn);



  }
  if( rc ) sqlite3_result_error_code(context, rc);
}

/*
** An SQL user-function registered to do the work of an DETACH statement. The
** three arguments to the function come directly from a detach statement:
................................................................................
  Parse *pParse,      /* Error messages will be written here */
  int iDb,            /* This is the database that must be used */
  const char *zType,  /* "view", "trigger", or "index" */
  const Token *pName  /* Name of the view, trigger, or index */
){
  sqlite3 *db;

  if( NEVER(iDb<0) || iDb==1 ) return 0;
  db = pParse->db;
  assert( db->nDb>iDb );
  pFix->pParse = pParse;
  pFix->zDb = db->aDb[iDb].zName;
  pFix->zType = zType;
  pFix->pName = pName;
  return 1;
................................................................................
  DbFixer *pFix,       /* Context of the fixation */
  SrcList *pList       /* The Source list to check and modify */
){
  int i;
  const char *zDb;
  struct SrcList_item *pItem;

  if( NEVER(pList==0) ) return 0;
  zDb = pFix->zDb;
  for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
    if( pItem->zDatabase==0 ){
      pItem->zDatabase = sqlite3DbStrDup(pFix->pParse->db, zDb);
    }else if( sqlite3StrICmp(pItem->zDatabase,zDb)!=0 ){
      sqlite3ErrorMsg(pFix->pParse,
         "%s %T cannot reference objects in database %s",