Fix for ticket #62: Do not report an SQLITE_READONLY error until the application

actually tries to write data into a readonly file.  It is OK to start a
transaction on a read-only file, and doing so will get you a read lock.  This
change allows TEMP tables to be read/write even though the main database is
readonly. (CVS 607)

FossilOrigin-Name: 9ef795d1d756a404d2123ebc19df1985b19c9888

manifest

@@ -1,5 +1,5 @@
-C Additional\sgrammar\scleanup\sresulting\sfrom\sthe\s%fallback\sdirective.\s(CVS\s606)
+C Fix\sfor\sticket\s#62:\sDo\snot\sreport\san\sSQLITE_READONLY\serror\suntil\sthe\sapplication\nactually\stries\sto\swrite\sdata\sinto\sa\sreadonly\sfile.\s\sIt\sis\sOK\sto\sstart\sa\ntransaction\son\sa\sread-only\sfile,\sand\sdoing\sso\swill\sget\syou\sa\sread\slock.\s\sThis\nchange\sallows\sTEMP\stables\sto\sbe\sread/write\seven\sthough\sthe\smain\sdatabase\sis\nreadonly.\s(CVS\s607)
-D 2002-06-06T19:04:16
+D 2002-06-06T23:16:05
 F Makefile.in 6291a33b87d2a395aafd7646ee1ed562c6f2c28c
 F Makefile.template 4e11752e0b5c7a043ca50af4296ec562857ba495
 F README a4c0ba11354ef6ba0776b400d057c59da47a4cc0
@@ -18,7 +18,7 @@ F publish.sh d115bd49631e3bb0d799e7dc1da51f9866d67647
 F spec.template 238f7db425a78dc1bb7682e56e3834c7270a3f5e
 F sqlite.1 83f4a9d37bdf2b7ef079a82d54eaf2e3509ee6ea
 F src/TODO af7f3cab0228e34149cf98e073aa83d45878e7e6
-F src/btree.c c01b404b9373ae1c0daf7d1f9211c72ead67638e
+F src/btree.c 8b86be8f234c1c5dab3186f69cee2544ec9d7257
 F src/btree.h 8abeabfe6e0b1a990b64fa457592a6482f6674f3
 F src/build.c 36e42718a7a94f554ea39508993378482f5335c7
 F src/delete.c a2b098cbbf518e6b641847e26de85827793bc523
@@ -52,7 +52,7 @@ F src/tokenize.c 35c63867d03fcaf81fe520f8d8206981d0c7270e
 F src/trigger.c d02f8e3510c7c2ad948a0e8c3bb0cca8adaf80c5
 F src/update.c f68375173bf5338cae3e97012708e10f206aedd9
 F src/util.c 7cf46b5612f5d12601c697374b9c6b38b2332ce8
-F src/vdbe.c ee08fbae7f7bfc150b5840ce69967c469c440752
+F src/vdbe.c 27b71e3c6cc77c071421b24462872f32047e2c20
 F src/vdbe.h b8706429131c14b307a07aab7e47f95a9da53610
 F src/where.c b054f2f23127bd57eb5f973bcd38764b875d73fe
 F test/all.test e4d3821eeba751829b419cd47814bd20af4286d1
@@ -98,7 +98,7 @@ F test/subselect.test f3bc1dcbddddcea08d818fcff75228ad3464fc83
 F test/table.test 42511f98a3e9bbee62913e3ae1774777faa23d35
 F test/tableapi.test 3c80421a889e1d106df16e5800fa787f0d2914a6
 F test/tclsqlite.test 79deeffd7cd637ca0f06c5dbbf2f44d272079533
-F test/temptable.test daa83489eea2e9aaeeece09675c28be84c72cb67
+F test/temptable.test ae58694c0fdd2d0b781508b64adc5aee3416aeed
 F test/tester.tcl dc1b56bd628b487e4d75bfd1e7480b5ed8810ac6
 F test/trans.test ae0b9a82d5d34122c3a3108781eb8d078091ccee
 F test/trigger1.test bb63749fa8a395a60541100607d86381604b7194
@@ -136,7 +136,7 @@ F www/speed.tcl da8afcc1d3ccc5696cfb388a68982bc3d9f7f00f
 F www/sqlite.tcl 8b5884354cb615049aed83039f8dfe1552a44279
 F www/tclsqlite.tcl 1db15abeb446aad0caf0b95b8b9579720e4ea331
 F www/vdbe.tcl 2013852c27a02a091d39a766bc87cff329f21218
-P 7ac5bd293cbb2bf252f31f1571f7efac7e77280a
+P c0cb3a012e02df1a7965413a92f9b5a77331edb4
-R d4345db261ae090ac6a58373d7650fb9
+R bbf73b9f76e1af31b5358613f061b43c
 U drh
-Z a44424a54b4cc26f96d80deba8206afd
+Z 202177a08e619734270177dc9e884211

manifest.uuid

@@ -1 +1 @@
-c0cb3a012e02df1a7965413a92f9b5a77331edb4
+9ef795d1d756a404d2123ebc19df1985b19c9888

src/btree.c

@@ -9,7 +9,7 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btree.c,v 1.61 2002/05/15 11:44:14 drh Exp $
+** $Id: btree.c,v 1.62 2002/06/06 23:16:05 drh Exp $
 **
 ** This file implements a external (disk-based) database using BTrees.
 ** For a detailed discussion of BTrees, refer to
@@ -317,6 +317,7 @@ struct Btree {
   PageOne *page1;       /* First page of the database */
   u8 inTrans;           /* True if a transaction is in progress */
   u8 inCkpt;            /* True if there is a checkpoint on the transaction */
+  u8 readOnly;          /* True if the underlying file is readonly */
   Hash locks;           /* Key: root page number.  Data: lock count */
 };
 typedef Btree Bt;
@@ -630,6 +631,7 @@ int sqliteBtreeOpen(
   sqlitepager_set_destructor(pBt->pPager, pageDestructor);
   pBt->pCursor = 0;
   pBt->page1 = 0;
+  pBt->readOnly = sqlitepager_isreadonly(pBt->pPager);
   sqliteHashInit(&pBt->locks, SQLITE_HASH_INT, 0);
   *ppBtree = pBt;
   return SQLITE_OK;
@@ -771,12 +773,13 @@ int sqliteBtreeBeginTrans(Btree *pBt){
       return rc;
     }
   }
-  if( sqlitepager_isreadonly(pBt->pPager) ){
+  if( pBt->readOnly ){
-    return SQLITE_READONLY;
+    rc = SQLITE_OK;
-  }
+  }else{
-  rc = sqlitepager_begin(pBt->page1);
+    rc = sqlitepager_begin(pBt->page1);
-  if( rc==SQLITE_OK ){
+    if( rc==SQLITE_OK ){
-    rc = newDatabase(pBt);
+      rc = newDatabase(pBt);
+    }
   }
   if( rc==SQLITE_OK ){
     pBt->inTrans = 1;
@@ -796,7 +799,7 @@ int sqliteBtreeBeginTrans(Btree *pBt){
 int sqliteBtreeCommit(Btree *pBt){
   int rc;
   if( pBt->inTrans==0 ) return SQLITE_ERROR;
-  rc = sqlitepager_commit(pBt->pPager);
+  rc = pBt->readOnly ? SQLITE_OK : sqlitepager_commit(pBt->pPager);
   pBt->inTrans = 0;
   pBt->inCkpt = 0;
   unlockBtreeIfUnused(pBt);
@@ -824,7 +827,7 @@ int sqliteBtreeRollback(Btree *pBt){
       pCur->pPage = 0;
     }
   }
-  rc = sqlitepager_rollback(pBt->pPager);
+  rc = pBt->readOnly ? SQLITE_OK : sqlitepager_rollback(pBt->pPager);
   unlockBtreeIfUnused(pBt);
   return rc;
 }
@@ -844,7 +847,7 @@ int sqliteBtreeBeginCkpt(Btree *pBt){
   if( !pBt->inTrans || pBt->inCkpt ){
     return SQLITE_ERROR;
   }
-  rc = sqlitepager_ckpt_begin(pBt->pPager);
+  rc = pBt->readOnly ? SQLITE_OK : sqlitepager_ckpt_begin(pBt->pPager);
   pBt->inCkpt = 1;
   return rc;
 }
@@ -856,7 +859,7 @@ int sqliteBtreeBeginCkpt(Btree *pBt){
 */
 int sqliteBtreeCommitCkpt(Btree *pBt){
   int rc;
-  if( pBt->inCkpt ){
+  if( pBt->inCkpt && !pBt->readOnly ){
     rc = sqlitepager_ckpt_commit(pBt->pPager);
   }else{
     rc = SQLITE_OK;
@@ -876,7 +879,7 @@ int sqliteBtreeCommitCkpt(Btree *pBt){
 int sqliteBtreeRollbackCkpt(Btree *pBt){
   int rc;
   BtCursor *pCur;
-  if( pBt->inCkpt==0 ) return SQLITE_OK;
+  if( pBt->inCkpt==0 || pBt->readOnly ) return SQLITE_OK;
   for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
     if( pCur->pPage ){
       sqlitepager_unref(pCur->pPage);
@@ -916,6 +919,10 @@ int sqliteBtreeCursor(Btree *pBt, int iTable, int wrFlag, BtCursor **ppCur){
       return rc;
     }
   }
+  if( wrFlag && pBt->readOnly ){
+    *ppCur = 0;
+    return SQLITE_READONLY;
+  }
   pCur = sqliteMalloc( sizeof(*pCur) );
   if( pCur==0 ){
     rc = SQLITE_NOMEM;
@@ -2422,6 +2429,9 @@ int sqliteBtreeCreateTable(Btree *pBt, int *piTable){
   if( !pBt->inTrans ){
     return SQLITE_ERROR;  /* Must start a transaction first */
   }
+  if( pBt->readOnly ){
+    return SQLITE_READONLY;
+  }
   rc = allocatePage(pBt, &pRoot, &pgnoRoot);
   if( rc ) return rc;
   assert( sqlitepager_iswriteable(pRoot) );
@@ -2441,19 +2451,7 @@ int sqliteBtreeCreateTable(Btree *pBt, int *piTable){
 ** BTree indices are restricted to having an arbitrary key and no data.
 */
 int sqliteBtreeCreateIndex(Btree *pBt, int *piIndex){
-  MemPage *pRoot;
+  return sqliteBtreeCreateTable(pBt, piIndex);
-  Pgno pgnoRoot;
-  int rc;
-  if( !pBt->inTrans ){
-    return SQLITE_ERROR;  /* Must start a transaction first */
-  }
-  rc = allocatePage(pBt, &pRoot, &pgnoRoot);
-  if( rc ) return rc;
-  assert( sqlitepager_iswriteable(pRoot) );
-  zeroPage(pRoot);
-  sqlitepager_unref(pRoot);
-  *piIndex = (int)pgnoRoot;
-  return SQLITE_OK;
 }
 
 /*
@@ -2503,6 +2501,9 @@ int sqliteBtreeClearTable(Btree *pBt, int iTable){
   if( !pBt->inTrans ){
     return SQLITE_ERROR;  /* Must start a transaction first */
   }
+  if( pBt->readOnly ){
+    return SQLITE_READONLY;
+  }
   nLock = (ptr)sqliteHashFind(&pBt->locks, 0, iTable);
   if( nLock ){
     return SQLITE_LOCKED;
@@ -2525,6 +2526,9 @@ int sqliteBtreeDropTable(Btree *pBt, int iTable){
   if( !pBt->inTrans ){
     return SQLITE_ERROR;  /* Must start a transaction first */
   }
+  if( pBt->readOnly ){
+    return SQLITE_READONLY;
+  }
   rc = sqlitepager_get(pBt->pPager, (Pgno)iTable, (void**)&pPage);
   if( rc ) return rc;
   rc = sqliteBtreeClearTable(pBt, iTable);
@@ -2562,6 +2566,9 @@ int sqliteBtreeUpdateMeta(Btree *pBt, int *aMeta){
   if( !pBt->inTrans ){
     return SQLITE_ERROR;  /* Must start a transaction first */
   }
+  if( pBt->readOnly ){
+    return SQLITE_READONLY;
+  }
   pP1 = pBt->page1;
   rc = sqlitepager_write(pP1);
   if( rc ) return rc;   

src/vdbe.c

@@ -30,7 +30,7 @@
 ** But other routines are also provided to help in building up
 ** a program instruction by instruction.
 **
-** $Id: vdbe.c,v 1.152 2002/06/01 21:41:10 drh Exp $
+** $Id: vdbe.c,v 1.153 2002/06/06 23:16:06 drh Exp $
 */
 #include "sqliteInt.h"
 #include <ctype.h>
@@ -4864,7 +4864,6 @@ cleanup:
       case OE_Rollback: {
         sqliteBtreeRollback(pBt);
         if( db->pBeTemp ) sqliteBtreeRollback(db->pBeTemp);
-        sqliteRollbackInternalChanges(db);
         db->flags &= ~SQLITE_InTrans;
         db->onError = OE_Default;
         break;
@@ -4873,13 +4872,13 @@ cleanup:
         if( undoTransOnError ){
           sqliteBtreeCommit(pBt);
           if( db->pBeTemp ) sqliteBtreeCommit(db->pBeTemp);
-          sqliteCommitInternalChanges(db);
           db->flags &= ~SQLITE_InTrans;
           db->onError = OE_Default;
         }
         break;
       }
     }
+    sqliteRollbackInternalChanges(db);
   }
   sqliteBtreeCommitCkpt(pBt);
   if( db->pBeTemp ) sqliteBtreeCommitCkpt(db->pBeTemp);

test/temptable.test

@@ -12,7 +12,7 @@
 #
 # This file implements tests for temporary tables and indices.
 #
-# $Id: temptable.test,v 1.5 2002/05/10 13:14:08 drh Exp $
+# $Id: temptable.test,v 1.6 2002/06/06 23:16:06 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -299,4 +299,57 @@ do_test temptable-5.9 {
 
 db2 close
 
+# Test for correct operation of read-only databases
+#
+do_test temptable-6.1 {
+  execsql {
+    CREATE TABLE t8(x);
+    INSERT INTO t8 VALUES('xyzzy');
+    SELECT * FROM t8;
+  }
+} {xyzzy}
+do_test temptable-6.2 {
+  db close
+  catch {file attributes test.db -permissions 0444}
+  catch {file attributes test.db -readonly 1}
+  sqlite db test.db
+  execsql {
+    SELECT * FROM t8;
+  }
+} {xyzzy}
+do_test temptable-6.3 {
+  catchsql {
+    CREATE TABLE t9(x,y);
+  }
+} {1 {attempt to write a readonly database}}
+do_test temptable-6.4 {
+  catchsql {
+    CREATE TEMP TABLE t9(x,y);
+  }
+} {0 {}}
+do_test temptable-6.5 {
+  catchsql {
+    INSERT INTO t9 VALUES(1,2);
+    SELECT * FROM t9;
+  }
+} {0 {1 2}}
+do_test temptable-6.6 {
+  catchsql {
+    INSERT INTO t8 VALUES('hello');
+    SELECT * FROM t8;
+  }
+} {1 {attempt to write a readonly database}}
+do_test temptable-6.7 {
+  catchsql {
+    SELECT * FROM t8,t9;
+  }
+} {0 {xyzzy 1 2}}
+do_test temptable-6.8 {
+  db close
+  sqlite db test.db
+  catchsql {
+    SELECT * FROM t8,t9;
+  }
+} {1 {no such table: t9}}
+
 finish_test