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sqlite/ext/misc/vtshim.c
mistachkin 2f31d02049 In the 'vtshim' extension, avoid accessing freed memory when handling errors from xCreate/xConnect.
FossilOrigin-Name: ffd559afd32dcdce9c733ebccdee88fda9b689cf
2017-01-19 18:20:36 +00:00

554 lines
15 KiB
C

/*
** 2013-06-12
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** 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.
**
*************************************************************************
**
** A shim that sits between the SQLite virtual table interface and
** runtimes with garbage collector based memory management.
*/
#include "sqlite3ext.h"
SQLITE_EXTENSION_INIT1
#include <assert.h>
#include <string.h>
#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Forward references */
typedef struct vtshim_aux vtshim_aux;
typedef struct vtshim_vtab vtshim_vtab;
typedef struct vtshim_cursor vtshim_cursor;
/* The vtshim_aux argument is the auxiliary parameter that is passed
** into sqlite3_create_module_v2().
*/
struct vtshim_aux {
void *pChildAux; /* pAux for child virtual tables */
void (*xChildDestroy)(void*); /* Destructor for pChildAux */
sqlite3_module *pMod; /* Methods for child virtual tables */
sqlite3 *db; /* The database to which we are attached */
char *zName; /* Name of the module */
int bDisposed; /* True if disposed */
vtshim_vtab *pAllVtab; /* List of all vtshim_vtab objects */
sqlite3_module sSelf; /* Methods used by this shim */
};
/* A vtshim virtual table object */
struct vtshim_vtab {
sqlite3_vtab base; /* Base class - must be first */
sqlite3_vtab *pChild; /* Child virtual table */
vtshim_aux *pAux; /* Pointer to vtshim_aux object */
vtshim_cursor *pAllCur; /* List of all cursors */
vtshim_vtab **ppPrev; /* Previous on list */
vtshim_vtab *pNext; /* Next on list */
};
/* A vtshim cursor object */
struct vtshim_cursor {
sqlite3_vtab_cursor base; /* Base class - must be first */
sqlite3_vtab_cursor *pChild; /* Cursor generated by the managed subclass */
vtshim_cursor **ppPrev; /* Previous on list of all cursors */
vtshim_cursor *pNext; /* Next on list of all cursors */
};
/* Macro used to copy the child vtable error message to outer vtable */
#define VTSHIM_COPY_ERRMSG() \
do { \
sqlite3_free(pVtab->base.zErrMsg); \
pVtab->base.zErrMsg = sqlite3_mprintf("%s", pVtab->pChild->zErrMsg); \
} while (0)
/* Methods for the vtshim module */
static int vtshimCreate(
sqlite3 *db,
void *ppAux,
int argc,
const char *const*argv,
sqlite3_vtab **ppVtab,
char **pzErr
){
vtshim_aux *pAux = (vtshim_aux*)ppAux;
vtshim_vtab *pNew;
int rc;
assert( db==pAux->db );
if( pAux->bDisposed ){
if( pzErr ){
*pzErr = sqlite3_mprintf("virtual table was disposed: \"%s\"",
pAux->zName);
}
return SQLITE_ERROR;
}
pNew = sqlite3_malloc( sizeof(*pNew) );
*ppVtab = (sqlite3_vtab*)pNew;
if( pNew==0 ) return SQLITE_NOMEM;
memset(pNew, 0, sizeof(*pNew));
rc = pAux->pMod->xCreate(db, pAux->pChildAux, argc, argv,
&pNew->pChild, pzErr);
if( rc ){
sqlite3_free(pNew);
*ppVtab = 0;
return rc;
}
pNew->pAux = pAux;
pNew->ppPrev = &pAux->pAllVtab;
pNew->pNext = pAux->pAllVtab;
if( pAux->pAllVtab ) pAux->pAllVtab->ppPrev = &pNew->pNext;
pAux->pAllVtab = pNew;
return rc;
}
static int vtshimConnect(
sqlite3 *db,
void *ppAux,
int argc,
const char *const*argv,
sqlite3_vtab **ppVtab,
char **pzErr
){
vtshim_aux *pAux = (vtshim_aux*)ppAux;
vtshim_vtab *pNew;
int rc;
assert( db==pAux->db );
if( pAux->bDisposed ){
if( pzErr ){
*pzErr = sqlite3_mprintf("virtual table was disposed: \"%s\"",
pAux->zName);
}
return SQLITE_ERROR;
}
pNew = sqlite3_malloc( sizeof(*pNew) );
*ppVtab = (sqlite3_vtab*)pNew;
if( pNew==0 ) return SQLITE_NOMEM;
memset(pNew, 0, sizeof(*pNew));
rc = pAux->pMod->xConnect(db, pAux->pChildAux, argc, argv,
&pNew->pChild, pzErr);
if( rc ){
sqlite3_free(pNew);
*ppVtab = 0;
return rc;
}
pNew->pAux = pAux;
pNew->ppPrev = &pAux->pAllVtab;
pNew->pNext = pAux->pAllVtab;
if( pAux->pAllVtab ) pAux->pAllVtab->ppPrev = &pNew->pNext;
pAux->pAllVtab = pNew;
return rc;
}
static int vtshimBestIndex(
sqlite3_vtab *pBase,
sqlite3_index_info *pIdxInfo
){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xBestIndex(pVtab->pChild, pIdxInfo);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimDisconnect(sqlite3_vtab *pBase){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc = SQLITE_OK;
if( !pAux->bDisposed ){
rc = pAux->pMod->xDisconnect(pVtab->pChild);
}
if( pVtab->pNext ) pVtab->pNext->ppPrev = pVtab->ppPrev;
*pVtab->ppPrev = pVtab->pNext;
sqlite3_free(pVtab);
return rc;
}
static int vtshimDestroy(sqlite3_vtab *pBase){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc = SQLITE_OK;
if( !pAux->bDisposed ){
rc = pAux->pMod->xDestroy(pVtab->pChild);
}
if( pVtab->pNext ) pVtab->pNext->ppPrev = pVtab->ppPrev;
*pVtab->ppPrev = pVtab->pNext;
sqlite3_free(pVtab);
return rc;
}
static int vtshimOpen(sqlite3_vtab *pBase, sqlite3_vtab_cursor **ppCursor){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
vtshim_cursor *pCur;
int rc;
*ppCursor = 0;
if( pAux->bDisposed ) return SQLITE_ERROR;
pCur = sqlite3_malloc( sizeof(*pCur) );
if( pCur==0 ) return SQLITE_NOMEM;
memset(pCur, 0, sizeof(*pCur));
rc = pAux->pMod->xOpen(pVtab->pChild, &pCur->pChild);
if( rc ){
sqlite3_free(pCur);
VTSHIM_COPY_ERRMSG();
return rc;
}
pCur->pChild->pVtab = pVtab->pChild;
*ppCursor = &pCur->base;
pCur->ppPrev = &pVtab->pAllCur;
if( pVtab->pAllCur ) pVtab->pAllCur->ppPrev = &pCur->pNext;
pCur->pNext = pVtab->pAllCur;
pVtab->pAllCur = pCur;
return SQLITE_OK;
}
static int vtshimClose(sqlite3_vtab_cursor *pX){
vtshim_cursor *pCur = (vtshim_cursor*)pX;
vtshim_vtab *pVtab = (vtshim_vtab*)pCur->base.pVtab;
vtshim_aux *pAux = pVtab->pAux;
int rc = SQLITE_OK;
if( !pAux->bDisposed ){
rc = pAux->pMod->xClose(pCur->pChild);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
}
if( pCur->pNext ) pCur->pNext->ppPrev = pCur->ppPrev;
*pCur->ppPrev = pCur->pNext;
sqlite3_free(pCur);
return rc;
}
static int vtshimFilter(
sqlite3_vtab_cursor *pX,
int idxNum,
const char *idxStr,
int argc,
sqlite3_value **argv
){
vtshim_cursor *pCur = (vtshim_cursor*)pX;
vtshim_vtab *pVtab = (vtshim_vtab*)pCur->base.pVtab;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xFilter(pCur->pChild, idxNum, idxStr, argc, argv);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimNext(sqlite3_vtab_cursor *pX){
vtshim_cursor *pCur = (vtshim_cursor*)pX;
vtshim_vtab *pVtab = (vtshim_vtab*)pCur->base.pVtab;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xNext(pCur->pChild);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimEof(sqlite3_vtab_cursor *pX){
vtshim_cursor *pCur = (vtshim_cursor*)pX;
vtshim_vtab *pVtab = (vtshim_vtab*)pCur->base.pVtab;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return 1;
rc = pAux->pMod->xEof(pCur->pChild);
VTSHIM_COPY_ERRMSG();
return rc;
}
static int vtshimColumn(sqlite3_vtab_cursor *pX, sqlite3_context *ctx, int i){
vtshim_cursor *pCur = (vtshim_cursor*)pX;
vtshim_vtab *pVtab = (vtshim_vtab*)pCur->base.pVtab;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xColumn(pCur->pChild, ctx, i);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimRowid(sqlite3_vtab_cursor *pX, sqlite3_int64 *pRowid){
vtshim_cursor *pCur = (vtshim_cursor*)pX;
vtshim_vtab *pVtab = (vtshim_vtab*)pCur->base.pVtab;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xRowid(pCur->pChild, pRowid);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimUpdate(
sqlite3_vtab *pBase,
int argc,
sqlite3_value **argv,
sqlite3_int64 *pRowid
){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xUpdate(pVtab->pChild, argc, argv, pRowid);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimBegin(sqlite3_vtab *pBase){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xBegin(pVtab->pChild);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimSync(sqlite3_vtab *pBase){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xSync(pVtab->pChild);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimCommit(sqlite3_vtab *pBase){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xCommit(pVtab->pChild);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimRollback(sqlite3_vtab *pBase){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xRollback(pVtab->pChild);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimFindFunction(
sqlite3_vtab *pBase,
int nArg,
const char *zName,
void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
void **ppArg
){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return 0;
rc = pAux->pMod->xFindFunction(pVtab->pChild, nArg, zName, pxFunc, ppArg);
VTSHIM_COPY_ERRMSG();
return rc;
}
static int vtshimRename(sqlite3_vtab *pBase, const char *zNewName){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xRename(pVtab->pChild, zNewName);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimSavepoint(sqlite3_vtab *pBase, int n){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xSavepoint(pVtab->pChild, n);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimRelease(sqlite3_vtab *pBase, int n){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xRelease(pVtab->pChild, n);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
static int vtshimRollbackTo(sqlite3_vtab *pBase, int n){
vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
vtshim_aux *pAux = pVtab->pAux;
int rc;
if( pAux->bDisposed ) return SQLITE_ERROR;
rc = pAux->pMod->xRollbackTo(pVtab->pChild, n);
if( rc!=SQLITE_OK ){
VTSHIM_COPY_ERRMSG();
}
return rc;
}
/* The destructor function for a disposible module */
static void vtshimAuxDestructor(void *pXAux){
vtshim_aux *pAux = (vtshim_aux*)pXAux;
assert( pAux->pAllVtab==0 );
if( !pAux->bDisposed && pAux->xChildDestroy ){
pAux->xChildDestroy(pAux->pChildAux);
pAux->xChildDestroy = 0;
}
sqlite3_free(pAux->zName);
sqlite3_free(pAux->pMod);
sqlite3_free(pAux);
}
static int vtshimCopyModule(
const sqlite3_module *pMod, /* Source module to be copied */
sqlite3_module **ppMod /* Destination for copied module */
){
sqlite3_module *p;
if( !pMod || !ppMod ) return SQLITE_ERROR;
p = sqlite3_malloc( sizeof(*p) );
if( p==0 ) return SQLITE_NOMEM;
memcpy(p, pMod, sizeof(*p));
*ppMod = p;
return SQLITE_OK;
}
#ifdef _WIN32
__declspec(dllexport)
#endif
void *sqlite3_create_disposable_module(
sqlite3 *db, /* SQLite connection to register module with */
const char *zName, /* Name of the module */
const sqlite3_module *p, /* Methods for the module */
void *pClientData, /* Client data for xCreate/xConnect */
void(*xDestroy)(void*) /* Module destructor function */
){
vtshim_aux *pAux;
sqlite3_module *pMod;
int rc;
pAux = sqlite3_malloc( sizeof(*pAux) );
if( pAux==0 ){
if( xDestroy ) xDestroy(pClientData);
return 0;
}
rc = vtshimCopyModule(p, &pMod);
if( rc!=SQLITE_OK ){
sqlite3_free(pAux);
return 0;
}
pAux->pChildAux = pClientData;
pAux->xChildDestroy = xDestroy;
pAux->pMod = pMod;
pAux->db = db;
pAux->zName = sqlite3_mprintf("%s", zName);
pAux->bDisposed = 0;
pAux->pAllVtab = 0;
pAux->sSelf.iVersion = p->iVersion<=2 ? p->iVersion : 2;
pAux->sSelf.xCreate = p->xCreate ? vtshimCreate : 0;
pAux->sSelf.xConnect = p->xConnect ? vtshimConnect : 0;
pAux->sSelf.xBestIndex = p->xBestIndex ? vtshimBestIndex : 0;
pAux->sSelf.xDisconnect = p->xDisconnect ? vtshimDisconnect : 0;
pAux->sSelf.xDestroy = p->xDestroy ? vtshimDestroy : 0;
pAux->sSelf.xOpen = p->xOpen ? vtshimOpen : 0;
pAux->sSelf.xClose = p->xClose ? vtshimClose : 0;
pAux->sSelf.xFilter = p->xFilter ? vtshimFilter : 0;
pAux->sSelf.xNext = p->xNext ? vtshimNext : 0;
pAux->sSelf.xEof = p->xEof ? vtshimEof : 0;
pAux->sSelf.xColumn = p->xColumn ? vtshimColumn : 0;
pAux->sSelf.xRowid = p->xRowid ? vtshimRowid : 0;
pAux->sSelf.xUpdate = p->xUpdate ? vtshimUpdate : 0;
pAux->sSelf.xBegin = p->xBegin ? vtshimBegin : 0;
pAux->sSelf.xSync = p->xSync ? vtshimSync : 0;
pAux->sSelf.xCommit = p->xCommit ? vtshimCommit : 0;
pAux->sSelf.xRollback = p->xRollback ? vtshimRollback : 0;
pAux->sSelf.xFindFunction = p->xFindFunction ? vtshimFindFunction : 0;
pAux->sSelf.xRename = p->xRename ? vtshimRename : 0;
if( p->iVersion>=2 ){
pAux->sSelf.xSavepoint = p->xSavepoint ? vtshimSavepoint : 0;
pAux->sSelf.xRelease = p->xRelease ? vtshimRelease : 0;
pAux->sSelf.xRollbackTo = p->xRollbackTo ? vtshimRollbackTo : 0;
}else{
pAux->sSelf.xSavepoint = 0;
pAux->sSelf.xRelease = 0;
pAux->sSelf.xRollbackTo = 0;
}
rc = sqlite3_create_module_v2(db, zName, &pAux->sSelf,
pAux, vtshimAuxDestructor);
return rc==SQLITE_OK ? (void*)pAux : 0;
}
#ifdef _WIN32
__declspec(dllexport)
#endif
void sqlite3_dispose_module(void *pX){
vtshim_aux *pAux = (vtshim_aux*)pX;
if( !pAux->bDisposed ){
vtshim_vtab *pVtab;
vtshim_cursor *pCur;
for(pVtab=pAux->pAllVtab; pVtab; pVtab=pVtab->pNext){
for(pCur=pVtab->pAllCur; pCur; pCur=pCur->pNext){
pAux->pMod->xClose(pCur->pChild);
}
pAux->pMod->xDisconnect(pVtab->pChild);
}
pAux->bDisposed = 1;
if( pAux->xChildDestroy ){
pAux->xChildDestroy(pAux->pChildAux);
pAux->xChildDestroy = 0;
}
}
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */
#ifdef _WIN32
__declspec(dllexport)
#endif
int sqlite3_vtshim_init(
sqlite3 *db,
char **pzErrMsg,
const sqlite3_api_routines *pApi
){
SQLITE_EXTENSION_INIT2(pApi);
return SQLITE_OK;
}