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mirror of https://github.com/sqlite/sqlite.git synced 2025-08-01 06:27:03 +03:00

Add locks to the in-memory database so that recursive writes will be detected

and rejected.  Ticket #436. (CVS 1090)

FossilOrigin-Name: 966b1a16f6687df08f8c21787c1c8b1af1d79e1e
This commit is contained in:
drh
2003-08-27 22:52:34 +00:00
parent ec1bd0bd72
commit 0d4f801c28
3 changed files with 72 additions and 15 deletions

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@ -1,5 +1,5 @@
C Fix\scompiler\swarnings\sunder\sOpenVMS.\s\sTicket\s#357.\s(CVS\s1088)
D 2003-08-26T11:41:27
C Add\slocks\sto\sthe\sin-memory\sdatabase\sso\sthat\srecursive\swrites\swill\sbe\sdetected\nand\srejected.\s\sTicket\s#436.\s(CVS\s1090)
D 2003-08-27T22:52:34
F Makefile.in f7e916ae863393827fa6a4cb292e3398096edcf1
F Makefile.linux-gcc b86a99c493a5bfb402d1d9178dcdc4bd4b32f906
F README f1de682fbbd94899d50aca13d387d1b3fd3be2dd
@ -23,7 +23,7 @@ F src/attach.c 9f78b4aaac02a2b09ff108e92cbaee3199e7962a
F src/auth.c c8f50d4507e37779d96ff3c55417bc2b612dfed6
F src/btree.c ba1cc0c71c3d2742b9a9047832335dc7d3656c45
F src/btree.h 9b7c09f1e64274d7bb74a57bbfc63778f67b1048
F src/btree_rb.c f30f5cddc4375c05bf361116da1492d9601760ca
F src/btree_rb.c 2f7ee4fa951d761c470ffadbf691883717a1efe7
F src/build.c 7cdc95266496f53673a66202477b137d514898cf
F src/copy.c 9e47975ea96751c658bcf1a0c4f0bb7c6ee61e73
F src/delete.c 0f81e6799c089487615d38e042a2de4d2d6192bc
@ -168,7 +168,7 @@ F www/speed.tcl 2f6b1155b99d39adb185f900456d1d592c4832b3
F www/sqlite.tcl 3c83b08cf9f18aa2d69453ff441a36c40e431604
F www/tclsqlite.tcl b9271d44dcf147a93c98f8ecf28c927307abd6da
F www/vdbe.tcl 9b9095d4495f37697fd1935d10e14c6015e80aa1
P cbe32216966c987902ceb4d85332fc95801dbda2
R ddd7131f94b88ef749e9dcf2a2026ce5
P c95f347cac27732533a2f6fd4ba50bf00eef59f3
R 002b3717598c8349a2d682847ae9c09b
U drh
Z bc22588721b74c4fdc0bad5666b4494e
Z 4b1d0cc8167eef257f9d48654435d622

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@ -1 +1 @@
c95f347cac27732533a2f6fd4ba50bf00eef59f3
966b1a16f6687df08f8c21787c1c8b1af1d79e1e

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@ -9,7 +9,7 @@
** May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree_rb.c,v 1.14 2003/06/29 18:29:48 drh Exp $
** $Id: btree_rb.c,v 1.15 2003/08/27 22:52:34 drh Exp $
**
** This file implements an in-core database using Red-Black balanced
** binary trees.
@ -99,7 +99,9 @@ struct RbtCursor {
BtRbTree *pTree;
int iTree; /* Index of pTree in pRbtree */
BtRbNode *pNode;
RbtCursor *pShared; /* List of all cursors on the same Rbtree */
u8 eSkip; /* Determines if next step operation is a no-op */
u8 wrFlag; /* True if this cursor is open for writing */
};
/*
@ -111,6 +113,7 @@ struct RbtCursor {
#define SKIP_INVALID 3 /* Calls to Next() and Previous() are invalid */
struct BtRbTree {
RbtCursor *pCursors; /* All cursors pointing to this tree */
BtRbNode *pHead; /* Head of the tree, or NULL */
};
@ -139,6 +142,33 @@ static int memRbtreeNext(RbtCursor* pCur, int *pRes);
static int memRbtreeLast(RbtCursor* pCur, int *pRes);
static int memRbtreePrevious(RbtCursor* pCur, int *pRes);
/*
** This routine checks all cursors that point to the same table
** as pCur points to. If any of those cursors were opened with
** wrFlag==0 then this routine returns SQLITE_LOCKED. If all
** cursors point to the same table were opened with wrFlag==1
** then this routine returns SQLITE_OK.
**
** In addition to checking for read-locks (where a read-lock
** means a cursor opened with wrFlag==0) this routine also NULLs
** out the pNode field of all other cursors.
** This is necessary because an insert
** or delete might change erase the node out from under
** another cursor.
*/
static int checkReadLocks(RbtCursor *pCur){
RbtCursor *p;
assert( pCur->wrFlag );
for(p=pCur->pTree->pCursors; p; p=p->pShared){
if( p!=pCur ){
if( p->wrFlag==0 ) return SQLITE_LOCKED;
p->pNode = 0;
}
}
return SQLITE_OK;
}
/*
* The key-compare function for the red-black trees. Returns as follows:
*
@ -636,6 +666,7 @@ static int memRbtreeDropTable(Rbtree* tree, int n)
memRbtreeClearTable(tree, n);
pTree = sqliteHashInsert(&tree->tblHash, 0, n, 0);
assert(pTree);
assert( pTree->pCursors==0 );
sqliteFree(pTree);
if( tree->eTransState != TRANS_ROLLBACK ){
@ -668,7 +699,7 @@ static int memRbtreeKeyCompare(RbtCursor* pCur, const void *pKey, int nKey,
/*
* Get a new cursor for table iTable of the supplied Rbtree. The wrFlag
* parameter is ignored, all cursors are capable of write-operations.
* parameter indicates that the cursor is open for writing.
*
* Note that RbtCursor.eSkip and RbtCursor.pNode both initialize to 0.
*/
@ -678,12 +709,17 @@ static int memRbtreeCursor(
int wrFlag,
RbtCursor **ppCur
){
RbtCursor *pCur;
assert(tree);
*ppCur = sqliteMalloc(sizeof(RbtCursor));
(*ppCur)->pTree = sqliteHashFind(&tree->tblHash, 0, iTable);
(*ppCur)->pRbtree = tree;
(*ppCur)->iTree = iTable;
(*ppCur)->pOps = &sqliteRbtreeCursorOps;
pCur = *ppCur = sqliteMalloc(sizeof(RbtCursor));
pCur->pTree = sqliteHashFind(&tree->tblHash, 0, iTable);
pCur->pRbtree = tree;
pCur->iTree = iTable;
pCur->pOps = &sqliteRbtreeCursorOps;
pCur->wrFlag = wrFlag;
pCur->pShared = pCur->pTree->pCursors;
pCur->pTree->pCursors = pCur;
assert( (*ppCur)->pTree );
return SQLITE_OK;
@ -711,6 +747,11 @@ static int memRbtreeInsert(
** not in a transaction */
assert( pCur->pRbtree->eTransState != TRANS_NONE );
/* Make sure some other cursor isn't trying to read this same table */
if( checkReadLocks(pCur) ){
return SQLITE_LOCKED; /* The table pCur points to has a read lock */
}
/* Take a copy of the input data now, in case we need it for the
* replace case */
pData = sqliteMalloc(nData);
@ -869,6 +910,11 @@ static int memRbtreeDelete(RbtCursor* pCur)
** not in a transaction */
assert( pCur->pRbtree->eTransState != TRANS_NONE );
/* Make sure some other cursor isn't trying to read this same table */
if( checkReadLocks(pCur) ){
return SQLITE_LOCKED; /* The table pCur points to has a read lock */
}
pZ = pCur->pNode;
if( !pZ ){
return SQLITE_OK;
@ -1146,6 +1192,16 @@ static int memRbtreeData(RbtCursor *pCur, int offset, int amt, char *zBuf)
static int memRbtreeCloseCursor(RbtCursor* pCur)
{
if( pCur->pTree->pCursors==pCur ){
pCur->pTree->pCursors = pCur->pShared;
}else{
RbtCursor *p = pCur->pTree->pCursors;
while( p && p->pShared!=pCur ){ p = p->pShared; }
assert( p!=0 );
if( p ){
p->pShared = pCur->pShared;
}
}
sqliteFree(pCur);
return SQLITE_OK;
}
@ -1249,6 +1305,7 @@ static void execute_rollback_list(Rbtree *pRbtree, BtRollbackOp *pList)
int res;
cur.pRbtree = pRbtree;
cur.wrFlag = 1;
while( pList ){
switch( pList->eOp ){
case ROLLBACK_INSERT: