Fix the memdb VFS so that it does not allow mmap if it is resizable, and so

that it never opens a disk file for any reason.

FossilOrigin-Name: 5ee14715a561d7522e9c6fd35a2ad3e6de526450025a99d2a523c2b27151be4f

1 files changed, 6 insertions, 7 deletions

diff --git a/src/memdb.c b/src/memdb.c
index 0d970b6ca..321ef6ff7 100644
--- a/src/memdb.c
+++ b/src/memdb.c
@@ -272,7 +272,7 @@ static int memdbRead(
 */
 static int memdbEnlarge(MemStore *p, sqlite3_int64 newSz){
   unsigned char *pNew;
-  if( (p->mFlags & SQLITE_DESERIALIZE_RESIZEABLE)==0 || p->nMmap>0 ){
+  if( (p->mFlags & SQLITE_DESERIALIZE_RESIZEABLE)==0 || NEVER(p->nMmap>0) ){
     return SQLITE_FULL;
   }
   if( newSz>p->szMax ){
@@ -471,7 +471,7 @@ static int memdbFetch(
 ){
   MemStore *p = ((MemFile*)pFile)->pStore;
   memdbEnter(p);
-  if( iOfst+iAmt>p->sz ){
+  if( iOfst+iAmt>p->sz || (p->mFlags & SQLITE_DESERIALIZE_RESIZEABLE)!=0 ){
     *pp = 0;
   }else{
     p->nMmap++;
@@ -505,9 +505,7 @@ static int memdbOpen(
   MemFile *pFile = (MemFile*)pFd;
   MemStore *p = 0;
   int szName;
-  if( (flags & SQLITE_OPEN_MAIN_DB)==0 ){
-    return ORIGVFS(pVfs)->xOpen(ORIGVFS(pVfs), zName, pFd, flags, pOutFlags);
-  }
+
   memset(pFile, 0, sizeof(*pFile));
   szName = sqlite3Strlen30(zName);
   if( szName>1 && zName[0]=='/' ){
@@ -567,8 +565,9 @@ static int memdbOpen(
     p->szMax = sqlite3GlobalConfig.mxMemdbSize;
   }
   pFile->pStore = p;
-  assert( pOutFlags!=0 );  /* True because flags==SQLITE_OPEN_MAIN_DB */
-  *pOutFlags = flags | SQLITE_OPEN_MEMORY;
+  if( pOutFlags!=0 ){
+    *pOutFlags = flags | SQLITE_OPEN_MEMORY;
+  }
   pFd->pMethods = &memdb_io_methods;
   memdbLeave(p);
   return SQLITE_OK;