DO NOT MERGE - Merge PPRL.190305.001 into master

Bug: 127812889
Change-Id: I33d269cfcbc281555c3ebbbb6c30574e41cc673c

5 files changed, 208 insertions, 94 deletions

diff --git a/dist/Android.patch b/dist/Android.patch
index acc8ffd..51ab92d 100644
--- a/dist/Android.patch
+++ b/dist/Android.patch
@@ -1,5 +1,5 @@
---- orig/shell.c	2018-02-18 23:53:25.407627650 -0800
-+++ shell.c	2018-02-18 23:53:25.467627374 -0800
+--- orig/shell.c	2019-01-07 14:22:53.308198437 -0800
++++ shell.c	2019-01-07 14:22:53.356198069 -0800
 @@ -87,6 +87,12 @@
  #endif
  #include <ctype.h>
@@ -37,8 +37,8 @@
      if( p->openMode==SHELL_OPEN_ZIPFILE ){
        char *zSql = sqlite3_mprintf(
           "CREATE VIRTUAL TABLE zip USING zipfile(%Q);", p->zDbFilename);
---- orig/sqlite3.c	2018-02-18 23:53:25.459627411 -0800
-+++ sqlite3.c	2018-08-22 15:28:04.016188846 -0700
+--- orig/sqlite3.c	2019-01-07 14:24:24.503497740 -0800
++++ sqlite3.c	2019-01-07 14:24:24.871494912 -0800
 @@ -30672,6 +30672,10 @@
  # include <sys/mount.h>
  #endif
diff --git a/dist/orig/sqlite3.c b/dist/orig/sqlite3.c
index 73c69ef..8e495f1 100644
--- a/dist/orig/sqlite3.c
+++ b/dist/orig/sqlite3.c
@@ -1149,7 +1149,7 @@ extern "C" {
 */
 #define SQLITE_VERSION        "3.22.0"
 #define SQLITE_VERSION_NUMBER 3022000
-#define SQLITE_SOURCE_ID      "2018-01-22 18:45:57 0c55d179733b46d8d0ba4d88e01a25e10677046ee3da1d5b1581e86726f2171d"
+#define SQLITE_SOURCE_ID      "2018-12-19 01:30:22 c255889bd95bd5430dc7ced3317011ae2abb483d6c9af883af3dc7d6c2c2f234"
 
 /*
 ** CAPI3REF: Run-Time Library Version Numbers
@@ -150618,7 +150618,7 @@ static int fts3ScanInteriorNode(
   const char *zCsr = zNode;       /* Cursor to iterate through node */
   const char *zEnd = &zCsr[nNode];/* End of interior node buffer */
   char *zBuffer = 0;              /* Buffer to load terms into */
-  int nAlloc = 0;                 /* Size of allocated buffer */
+  i64 nAlloc = 0;                 /* Size of allocated buffer */
   int isFirstTerm = 1;            /* True when processing first term on page */
   sqlite3_int64 iChild;           /* Block id of child node to descend to */
 
@@ -150656,14 +150656,14 @@ static int fts3ScanInteriorNode(
     zCsr += fts3GetVarint32(zCsr, &nSuffix);
     
     assert( nPrefix>=0 && nSuffix>=0 );
-    if( &zCsr[nSuffix]>zEnd ){
+    if( nPrefix>zCsr-zNode || nSuffix>zEnd-zCsr ){
       rc = FTS_CORRUPT_VTAB;
       goto finish_scan;
     }
-    if( nPrefix+nSuffix>nAlloc ){
+    if( (i64)nPrefix+nSuffix>nAlloc ){
       char *zNew;
-      nAlloc = (nPrefix+nSuffix) * 2;
-      zNew = (char *)sqlite3_realloc(zBuffer, nAlloc);
+      nAlloc = ((i64)nPrefix+nSuffix) * 2;
+      zNew = (char *)sqlite3_realloc64(zBuffer, nAlloc);
       if( !zNew ){
         rc = SQLITE_NOMEM;
         goto finish_scan;
@@ -160262,15 +160262,19 @@ static int fts3SegReaderNext(
   ** safe (no risk of overread) even if the node data is corrupted. */
   pNext += fts3GetVarint32(pNext, &nPrefix);
   pNext += fts3GetVarint32(pNext, &nSuffix);
-  if( nPrefix<0 || nSuffix<=0 
-   || &pNext[nSuffix]>&pReader->aNode[pReader->nNode] 
+  if( nSuffix<=0
+   || (&pReader->aNode[pReader->nNode] - pNext)<nSuffix
+   || nPrefix>pReader->nTermAlloc
   ){
     return FTS_CORRUPT_VTAB;
   }
 
-  if( nPrefix+nSuffix>pReader->nTermAlloc ){
-    int nNew = (nPrefix+nSuffix)*2;
-    char *zNew = sqlite3_realloc(pReader->zTerm, nNew);
+  /* Both nPrefix and nSuffix were read by fts3GetVarint32() and so are
+  ** between 0 and 0x7FFFFFFF. But the sum of the two may cause integer
+  ** overflow - hence the (i64) casts.  */
+  if( (i64)nPrefix+nSuffix>(i64)pReader->nTermAlloc ){
+    i64 nNew = ((i64)nPrefix+nSuffix)*2;
+    char *zNew = sqlite3_realloc64(pReader->zTerm, nNew);
     if( !zNew ){
       return SQLITE_NOMEM;
     }
@@ -160292,7 +160296,7 @@ static int fts3SegReaderNext(
   ** b-tree node. And that the final byte of the doclist is 0x00. If either 
   ** of these statements is untrue, then the data structure is corrupt.
   */
-  if( &pReader->aDoclist[pReader->nDoclist]>&pReader->aNode[pReader->nNode] 
+  if( (&pReader->aNode[pReader->nNode] - pReader->aDoclist)<pReader->nDoclist
    || (pReader->nPopulate==0 && pReader->aDoclist[pReader->nDoclist-1])
   ){
     return FTS_CORRUPT_VTAB;
@@ -162615,6 +162619,9 @@ static int nodeReaderNext(NodeReader *p){
     }
     p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &nSuffix);
 
+    if( nPrefix>p->iOff || nSuffix>p->nNode-p->iOff ){
+      return SQLITE_CORRUPT_VTAB;
+    }
     blobGrowBuffer(&p->term, nPrefix+nSuffix, &rc);
     if( rc==SQLITE_OK ){
       memcpy(&p->term.a[nPrefix], &p->aNode[p->iOff], nSuffix);
@@ -162622,6 +162629,9 @@ static int nodeReaderNext(NodeReader *p){
       p->iOff += nSuffix;
       if( p->iChild==0 ){
         p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &p->nDoclist);
+        if( (p->nNode-p->iOff)<p->nDoclist ){
+          return SQLITE_CORRUPT_VTAB;
+        }
         p->aDoclist = &p->aNode[p->iOff];
         p->iOff += p->nDoclist;
       }
@@ -162629,7 +162639,6 @@ static int nodeReaderNext(NodeReader *p){
   }
 
   assert( p->iOff<=p->nNode );
-
   return rc;
 }
 
@@ -173110,7 +173119,8 @@ struct rbu_vfs {
   sqlite3_vfs *pRealVfs;          /* Underlying VFS */
   sqlite3_mutex *mutex;           /* Mutex to protect pMain */
   sqlite3rbu *pRbu;               /* Owner RBU object */
-  rbu_file *pMain;                /* Linked list of main db files */
+  rbu_file *pMain;                /* List of main db files */
+  rbu_file *pMainRbu;             /* List of main db files with pRbu!=0 */
 };
 
 /*
@@ -173139,6 +173149,7 @@ struct rbu_file {
   const char *zWal;               /* Wal filename for this main db file */
   rbu_file *pWalFd;               /* Wal file descriptor for this main db */
   rbu_file *pMainNext;            /* Next MAIN_DB file */
+  rbu_file *pMainRbuNext;         /* Next MAIN_DB file with pRbu!=0 */
 };
 
 /*
@@ -174517,7 +174528,7 @@ static void rbuCreateImposterTable2(sqlite3rbu *p, RbuObjIter *pIter){
         int iCid = sqlite3_column_int(pXInfo, 1);
         int bDesc = sqlite3_column_int(pXInfo, 3);
         const char *zCollate = (const char*)sqlite3_column_text(pXInfo, 4);
-        zCols = rbuMPrintf(p, "%z%sc%d %s COLLATE %s", zCols, zComma, 
+        zCols = rbuMPrintf(p, "%z%sc%d %s COLLATE %Q", zCols, zComma,
             iCid, pIter->azTblType[iCid], zCollate
         );
         zPk = rbuMPrintf(p, "%z%sc%d%s", zPk, zComma, iCid, bDesc?" DESC":"");
@@ -174578,7 +174589,7 @@ static void rbuCreateImposterTable(sqlite3rbu *p, RbuObjIter *pIter){
         ** "PRIMARY KEY" to the imposter table column declaration. */
         zPk = "PRIMARY KEY ";
       }
-      zSql = rbuMPrintf(p, "%z%s\"%w\" %s %sCOLLATE %s%s", 
+      zSql = rbuMPrintf(p, "%z%s\"%w\" %s %sCOLLATE %Q%s",
           zSql, zComma, zCol, pIter->azTblType[iCol], zPk, zColl,
           (pIter->abNotNull[iCol] ? " NOT NULL" : "")
       );
@@ -176728,6 +176739,69 @@ static int rbuUpdateTempSize(rbu_file *pFd, sqlite3_int64 nNew){
 }
 
 /*
+** Add an item to the main-db lists, if it is not already present.
+**
+** There are two main-db lists. One for all file descriptors, and one
+** for all file descriptors with rbu_file.pDb!=0. If the argument has
+** rbu_file.pDb!=0, then it is assumed to already be present on the
+** main list and is only added to the pDb!=0 list.
+*/
+static void rbuMainlistAdd(rbu_file *p){
+  rbu_vfs *pRbuVfs = p->pRbuVfs;
+  rbu_file *pIter;
+  assert( (p->openFlags & SQLITE_OPEN_MAIN_DB) );
+  sqlite3_mutex_enter(pRbuVfs->mutex);
+  if( p->pRbu==0 ){
+    for(pIter=pRbuVfs->pMain; pIter; pIter=pIter->pMainNext);
+    p->pMainNext = pRbuVfs->pMain;
+    pRbuVfs->pMain = p;
+  }else{
+    for(pIter=pRbuVfs->pMainRbu; pIter && pIter!=p; pIter=pIter->pMainRbuNext){}
+    if( pIter==0 ){
+      p->pMainRbuNext = pRbuVfs->pMainRbu;
+      pRbuVfs->pMainRbu = p;
+    }
+  }
+  sqlite3_mutex_leave(pRbuVfs->mutex);
+}
+
+/*
+** Remove an item from the main-db lists.
+*/
+static void rbuMainlistRemove(rbu_file *p){
+  rbu_file **pp;
+  sqlite3_mutex_enter(p->pRbuVfs->mutex);
+  for(pp=&p->pRbuVfs->pMain; *pp && *pp!=p; pp=&((*pp)->pMainNext)){}
+  if( *pp ) *pp = p->pMainNext;
+  p->pMainNext = 0;
+  for(pp=&p->pRbuVfs->pMainRbu; *pp && *pp!=p; pp=&((*pp)->pMainRbuNext)){}
+  if( *pp ) *pp = p->pMainRbuNext;
+  p->pMainRbuNext = 0;
+  sqlite3_mutex_leave(p->pRbuVfs->mutex);
+}
+
+/*
+** Given that zWal points to a buffer containing a wal file name passed to
+** either the xOpen() or xAccess() VFS method, search the main-db list for
+** a file-handle opened by the same database connection on the corresponding
+** database file.
+**
+** If parameter bRbu is true, only search for file-descriptors with
+** rbu_file.pDb!=0.
+*/
+static rbu_file *rbuFindMaindb(rbu_vfs *pRbuVfs, const char *zWal, int bRbu){
+  rbu_file *pDb;
+  sqlite3_mutex_enter(pRbuVfs->mutex);
+  if( bRbu ){
+    for(pDb=pRbuVfs->pMainRbu; pDb && pDb->zWal!=zWal; pDb=pDb->pMainRbuNext){}
+  }else{
+    for(pDb=pRbuVfs->pMain; pDb && pDb->zWal!=zWal; pDb=pDb->pMainNext){}
+  }
+  sqlite3_mutex_leave(pRbuVfs->mutex);
+  return pDb;
+}
+
+/*
 ** Close an rbu file.
 */
 static int rbuVfsClose(sqlite3_file *pFile){
@@ -176744,17 +176818,14 @@ static int rbuVfsClose(sqlite3_file *pFile){
   sqlite3_free(p->zDel);
 
   if( p->openFlags & SQLITE_OPEN_MAIN_DB ){
-    rbu_file **pp;
-    sqlite3_mutex_enter(p->pRbuVfs->mutex);
-    for(pp=&p->pRbuVfs->pMain; *pp!=p; pp=&((*pp)->pMainNext));
-    *pp = p->pMainNext;
-    sqlite3_mutex_leave(p->pRbuVfs->mutex);
+    rbuMainlistRemove(p);
     rbuUnlockShm(p);
     p->pReal->pMethods->xShmUnmap(p->pReal, 0);
   }
   else if( (p->openFlags & SQLITE_OPEN_DELETEONCLOSE) && p->pRbu ){
     rbuUpdateTempSize(p, 0);
   }
+  assert( p->pMainNext==0 && p->pRbuVfs->pMain!=p );
 
   /* Close the underlying file handle */
   rc = p->pReal->pMethods->xClose(p->pReal);
@@ -177013,6 +177084,9 @@ static int rbuVfsFileControl(sqlite3_file *pFile, int op, void *pArg){
       }else if( rc==SQLITE_NOTFOUND ){
         pRbu->pTargetFd = p;
         p->pRbu = pRbu;
+        if( p->openFlags & SQLITE_OPEN_MAIN_DB ){
+          rbuMainlistAdd(p);
+        }
         if( p->pWalFd ) p->pWalFd->pRbu = pRbu;
         rc = SQLITE_OK;
       }
@@ -177174,20 +177248,6 @@ static int rbuVfsShmUnmap(sqlite3_file *pFile, int delFlag){
   return rc;
 }
 
-/*
-** Given that zWal points to a buffer containing a wal file name passed to 
-** either the xOpen() or xAccess() VFS method, return a pointer to the
-** file-handle opened by the same database connection on the corresponding
-** database file.
-*/
-static rbu_file *rbuFindMaindb(rbu_vfs *pRbuVfs, const char *zWal){
-  rbu_file *pDb;
-  sqlite3_mutex_enter(pRbuVfs->mutex);
-  for(pDb=pRbuVfs->pMain; pDb && pDb->zWal!=zWal; pDb=pDb->pMainNext){}
-  sqlite3_mutex_leave(pRbuVfs->mutex);
-  return pDb;
-}
-
 /* 
 ** A main database named zName has just been opened. The following 
 ** function returns a pointer to a buffer owned by SQLite that contains
@@ -177266,7 +177326,7 @@ static int rbuVfsOpen(
       pFd->zWal = rbuMainToWal(zName, flags);
     }
     else if( flags & SQLITE_OPEN_WAL ){
-      rbu_file *pDb = rbuFindMaindb(pRbuVfs, zName);
+      rbu_file *pDb = rbuFindMaindb(pRbuVfs, zName, 0);
       if( pDb ){
         if( pDb->pRbu && pDb->pRbu->eStage==RBU_STAGE_OAL ){
           /* This call is to open a *-wal file. Intead, open the *-oal. This
@@ -177318,10 +177378,7 @@ static int rbuVfsOpen(
     ** mutex protected linked list of all such files.  */
     pFile->pMethods = &rbuvfs_io_methods;
     if( flags & SQLITE_OPEN_MAIN_DB ){
-      sqlite3_mutex_enter(pRbuVfs->mutex);
-      pFd->pMainNext = pRbuVfs->pMain;
-      pRbuVfs->pMain = pFd;
-      sqlite3_mutex_leave(pRbuVfs->mutex);
+      rbuMainlistAdd(pFd);
     }
   }else{
     sqlite3_free(pFd->zDel);
@@ -177369,7 +177426,7 @@ static int rbuVfsAccess(
   **      file opened instead.
   */
   if( rc==SQLITE_OK && flags==SQLITE_ACCESS_EXISTS ){
-    rbu_file *pDb = rbuFindMaindb(pRbuVfs, zPath);
+    rbu_file *pDb = rbuFindMaindb(pRbuVfs, zPath, 1);
     if( pDb && pDb->pRbu && pDb->pRbu->eStage==RBU_STAGE_OAL ){
       if( *pResOut ){
         rc = SQLITE_CANTOPEN;
@@ -203333,7 +203390,7 @@ static void fts5SourceIdFunc(
 ){
   assert( nArg==0 );
   UNUSED_PARAM2(nArg, apUnused);
-  sqlite3_result_text(pCtx, "fts5: 2018-01-22 18:45:57 0c55d179733b46d8d0ba4d88e01a25e10677046ee3da1d5b1581e86726f2171d", -1, SQLITE_TRANSIENT);
+  sqlite3_result_text(pCtx, "fts5: 2018-12-19 01:30:22 c255889bd95bd5430dc7ced3317011ae2abb483d6c9af883af3dc7d6c2c2f234", -1, SQLITE_TRANSIENT);
 }
 
 static int fts5Init(sqlite3 *db){
@@ -207601,9 +207658,9 @@ SQLITE_API int sqlite3_stmt_init(
 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_STMTVTAB) */
 
 /************** End of stmt.c ************************************************/
-#if __LINE__!=207604
+#if __LINE__!=207661
 #undef SQLITE_SOURCE_ID
-#define SQLITE_SOURCE_ID      "2018-01-22 18:45:57 0c55d179733b46d8d0ba4d88e01a25e10677046ee3da1d5b1581e86726f2alt2"
+#define SQLITE_SOURCE_ID      "2018-12-19 01:30:22 c255889bd95bd5430dc7ced3317011ae2abb483d6c9af883af3dc7d6c2c2alt2"
 #endif
 /* Return the source-id for this library */
 SQLITE_API const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
diff --git a/dist/orig/sqlite3.h b/dist/orig/sqlite3.h
index d8138b7..57669e1 100644
--- a/dist/orig/sqlite3.h
+++ b/dist/orig/sqlite3.h
@@ -125,7 +125,7 @@ extern "C" {
 */
 #define SQLITE_VERSION        "3.22.0"
 #define SQLITE_VERSION_NUMBER 3022000
-#define SQLITE_SOURCE_ID      "2018-01-22 18:45:57 0c55d179733b46d8d0ba4d88e01a25e10677046ee3da1d5b1581e86726f2171d"
+#define SQLITE_SOURCE_ID      "2018-12-19 01:30:22 c255889bd95bd5430dc7ced3317011ae2abb483d6c9af883af3dc7d6c2c2f234"
 
 /*
 ** CAPI3REF: Run-Time Library Version Numbers
diff --git a/dist/sqlite3.c b/dist/sqlite3.c
index 791332c..18b8246 100644
--- a/dist/sqlite3.c
+++ b/dist/sqlite3.c
@@ -1149,7 +1149,7 @@ extern "C" {
 */
 #define SQLITE_VERSION        "3.22.0"
 #define SQLITE_VERSION_NUMBER 3022000
-#define SQLITE_SOURCE_ID      "2018-01-22 18:45:57 0c55d179733b46d8d0ba4d88e01a25e10677046ee3da1d5b1581e86726f2171d"
+#define SQLITE_SOURCE_ID      "2018-12-19 01:30:22 c255889bd95bd5430dc7ced3317011ae2abb483d6c9af883af3dc7d6c2c2f234"
 
 /*
 ** CAPI3REF: Run-Time Library Version Numbers
@@ -150634,7 +150634,7 @@ static int fts3ScanInteriorNode(
   const char *zCsr = zNode;       /* Cursor to iterate through node */
   const char *zEnd = &zCsr[nNode];/* End of interior node buffer */
   char *zBuffer = 0;              /* Buffer to load terms into */
-  int nAlloc = 0;                 /* Size of allocated buffer */
+  i64 nAlloc = 0;                 /* Size of allocated buffer */
   int isFirstTerm = 1;            /* True when processing first term on page */
   sqlite3_int64 iChild;           /* Block id of child node to descend to */
 
@@ -150672,14 +150672,14 @@ static int fts3ScanInteriorNode(
     zCsr += fts3GetVarint32(zCsr, &nSuffix);
     
     assert( nPrefix>=0 && nSuffix>=0 );
-    if( &zCsr[nSuffix]>zEnd ){
+    if( nPrefix>zCsr-zNode || nSuffix>zEnd-zCsr ){
       rc = FTS_CORRUPT_VTAB;
       goto finish_scan;
     }
-    if( nPrefix+nSuffix>nAlloc ){
+    if( (i64)nPrefix+nSuffix>nAlloc ){
       char *zNew;
-      nAlloc = (nPrefix+nSuffix) * 2;
-      zNew = (char *)sqlite3_realloc(zBuffer, nAlloc);
+      nAlloc = ((i64)nPrefix+nSuffix) * 2;
+      zNew = (char *)sqlite3_realloc64(zBuffer, nAlloc);
       if( !zNew ){
         rc = SQLITE_NOMEM;
         goto finish_scan;
@@ -160290,15 +160290,19 @@ static int fts3SegReaderNext(
   ** safe (no risk of overread) even if the node data is corrupted. */
   pNext += fts3GetVarint32(pNext, &nPrefix);
   pNext += fts3GetVarint32(pNext, &nSuffix);
-  if( nPrefix<0 || nSuffix<=0 
-   || &pNext[nSuffix]>&pReader->aNode[pReader->nNode] 
+  if( nSuffix<=0
+   || (&pReader->aNode[pReader->nNode] - pNext)<nSuffix
+   || nPrefix>pReader->nTermAlloc
   ){
     return FTS_CORRUPT_VTAB;
   }
 
-  if( nPrefix+nSuffix>pReader->nTermAlloc ){
-    int nNew = (nPrefix+nSuffix)*2;
-    char *zNew = sqlite3_realloc(pReader->zTerm, nNew);
+  /* Both nPrefix and nSuffix were read by fts3GetVarint32() and so are
+  ** between 0 and 0x7FFFFFFF. But the sum of the two may cause integer
+  ** overflow - hence the (i64) casts.  */
+  if( (i64)nPrefix+nSuffix>(i64)pReader->nTermAlloc ){
+    i64 nNew = ((i64)nPrefix+nSuffix)*2;
+    char *zNew = sqlite3_realloc64(pReader->zTerm, nNew);
     if( !zNew ){
       return SQLITE_NOMEM;
     }
@@ -160320,7 +160324,7 @@ static int fts3SegReaderNext(
   ** b-tree node. And that the final byte of the doclist is 0x00. If either 
   ** of these statements is untrue, then the data structure is corrupt.
   */
-  if( &pReader->aDoclist[pReader->nDoclist]>&pReader->aNode[pReader->nNode] 
+  if( (&pReader->aNode[pReader->nNode] - pReader->aDoclist)<pReader->nDoclist
    || (pReader->nPopulate==0 && pReader->aDoclist[pReader->nDoclist-1])
   ){
     return FTS_CORRUPT_VTAB;
@@ -162643,6 +162647,9 @@ static int nodeReaderNext(NodeReader *p){
     }
     p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &nSuffix);
 
+    if( nPrefix>p->iOff || nSuffix>p->nNode-p->iOff ){
+      return SQLITE_CORRUPT_VTAB;
+    }
     blobGrowBuffer(&p->term, nPrefix+nSuffix, &rc);
     if( rc==SQLITE_OK ){
       memcpy(&p->term.a[nPrefix], &p->aNode[p->iOff], nSuffix);
@@ -162650,6 +162657,9 @@ static int nodeReaderNext(NodeReader *p){
       p->iOff += nSuffix;
       if( p->iChild==0 ){
         p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &p->nDoclist);
+        if( (p->nNode-p->iOff)<p->nDoclist ){
+          return SQLITE_CORRUPT_VTAB;
+        }
         p->aDoclist = &p->aNode[p->iOff];
         p->iOff += p->nDoclist;
       }
@@ -162657,7 +162667,6 @@ static int nodeReaderNext(NodeReader *p){
   }
 
   assert( p->iOff<=p->nNode );
-
   return rc;
 }
 
@@ -173138,7 +173147,8 @@ struct rbu_vfs {
   sqlite3_vfs *pRealVfs;          /* Underlying VFS */
   sqlite3_mutex *mutex;           /* Mutex to protect pMain */
   sqlite3rbu *pRbu;               /* Owner RBU object */
-  rbu_file *pMain;                /* Linked list of main db files */
+  rbu_file *pMain;                /* List of main db files */
+  rbu_file *pMainRbu;             /* List of main db files with pRbu!=0 */
 };
 
 /*
@@ -173167,6 +173177,7 @@ struct rbu_file {
   const char *zWal;               /* Wal filename for this main db file */
   rbu_file *pWalFd;               /* Wal file descriptor for this main db */
   rbu_file *pMainNext;            /* Next MAIN_DB file */
+  rbu_file *pMainRbuNext;         /* Next MAIN_DB file with pRbu!=0 */
 };
 
 /*
@@ -174545,7 +174556,7 @@ static void rbuCreateImposterTable2(sqlite3rbu *p, RbuObjIter *pIter){
         int iCid = sqlite3_column_int(pXInfo, 1);
         int bDesc = sqlite3_column_int(pXInfo, 3);
         const char *zCollate = (const char*)sqlite3_column_text(pXInfo, 4);
-        zCols = rbuMPrintf(p, "%z%sc%d %s COLLATE %s", zCols, zComma, 
+        zCols = rbuMPrintf(p, "%z%sc%d %s COLLATE %Q", zCols, zComma,
             iCid, pIter->azTblType[iCid], zCollate
         );
         zPk = rbuMPrintf(p, "%z%sc%d%s", zPk, zComma, iCid, bDesc?" DESC":"");
@@ -174606,7 +174617,7 @@ static void rbuCreateImposterTable(sqlite3rbu *p, RbuObjIter *pIter){
         ** "PRIMARY KEY" to the imposter table column declaration. */
         zPk = "PRIMARY KEY ";
       }
-      zSql = rbuMPrintf(p, "%z%s\"%w\" %s %sCOLLATE %s%s", 
+      zSql = rbuMPrintf(p, "%z%s\"%w\" %s %sCOLLATE %Q%s",
           zSql, zComma, zCol, pIter->azTblType[iCol], zPk, zColl,
           (pIter->abNotNull[iCol] ? " NOT NULL" : "")
       );
@@ -176756,6 +176767,69 @@ static int rbuUpdateTempSize(rbu_file *pFd, sqlite3_int64 nNew){
 }
 
 /*
+** Add an item to the main-db lists, if it is not already present.
+**
+** There are two main-db lists. One for all file descriptors, and one
+** for all file descriptors with rbu_file.pDb!=0. If the argument has
+** rbu_file.pDb!=0, then it is assumed to already be present on the
+** main list and is only added to the pDb!=0 list.
+*/
+static void rbuMainlistAdd(rbu_file *p){
+  rbu_vfs *pRbuVfs = p->pRbuVfs;
+  rbu_file *pIter;
+  assert( (p->openFlags & SQLITE_OPEN_MAIN_DB) );
+  sqlite3_mutex_enter(pRbuVfs->mutex);
+  if( p->pRbu==0 ){
+    for(pIter=pRbuVfs->pMain; pIter; pIter=pIter->pMainNext);
+    p->pMainNext = pRbuVfs->pMain;
+    pRbuVfs->pMain = p;
+  }else{
+    for(pIter=pRbuVfs->pMainRbu; pIter && pIter!=p; pIter=pIter->pMainRbuNext){}
+    if( pIter==0 ){
+      p->pMainRbuNext = pRbuVfs->pMainRbu;
+      pRbuVfs->pMainRbu = p;
+    }
+  }
+  sqlite3_mutex_leave(pRbuVfs->mutex);
+}
+
+/*
+** Remove an item from the main-db lists.
+*/
+static void rbuMainlistRemove(rbu_file *p){
+  rbu_file **pp;
+  sqlite3_mutex_enter(p->pRbuVfs->mutex);
+  for(pp=&p->pRbuVfs->pMain; *pp && *pp!=p; pp=&((*pp)->pMainNext)){}
+  if( *pp ) *pp = p->pMainNext;
+  p->pMainNext = 0;
+  for(pp=&p->pRbuVfs->pMainRbu; *pp && *pp!=p; pp=&((*pp)->pMainRbuNext)){}
+  if( *pp ) *pp = p->pMainRbuNext;
+  p->pMainRbuNext = 0;
+  sqlite3_mutex_leave(p->pRbuVfs->mutex);
+}
+
+/*
+** Given that zWal points to a buffer containing a wal file name passed to
+** either the xOpen() or xAccess() VFS method, search the main-db list for
+** a file-handle opened by the same database connection on the corresponding
+** database file.
+**
+** If parameter bRbu is true, only search for file-descriptors with
+** rbu_file.pDb!=0.
+*/
+static rbu_file *rbuFindMaindb(rbu_vfs *pRbuVfs, const char *zWal, int bRbu){
+  rbu_file *pDb;
+  sqlite3_mutex_enter(pRbuVfs->mutex);
+  if( bRbu ){
+    for(pDb=pRbuVfs->pMainRbu; pDb && pDb->zWal!=zWal; pDb=pDb->pMainRbuNext){}
+  }else{
+    for(pDb=pRbuVfs->pMain; pDb && pDb->zWal!=zWal; pDb=pDb->pMainNext){}
+  }
+  sqlite3_mutex_leave(pRbuVfs->mutex);
+  return pDb;
+}
+
+/*
 ** Close an rbu file.
 */
 static int rbuVfsClose(sqlite3_file *pFile){
@@ -176772,17 +176846,14 @@ static int rbuVfsClose(sqlite3_file *pFile){
   sqlite3_free(p->zDel);
 
   if( p->openFlags & SQLITE_OPEN_MAIN_DB ){
-    rbu_file **pp;
-    sqlite3_mutex_enter(p->pRbuVfs->mutex);
-    for(pp=&p->pRbuVfs->pMain; *pp!=p; pp=&((*pp)->pMainNext));
-    *pp = p->pMainNext;
-    sqlite3_mutex_leave(p->pRbuVfs->mutex);
+    rbuMainlistRemove(p);
     rbuUnlockShm(p);
     p->pReal->pMethods->xShmUnmap(p->pReal, 0);
   }
   else if( (p->openFlags & SQLITE_OPEN_DELETEONCLOSE) && p->pRbu ){
     rbuUpdateTempSize(p, 0);
   }
+  assert( p->pMainNext==0 && p->pRbuVfs->pMain!=p );
 
   /* Close the underlying file handle */
   rc = p->pReal->pMethods->xClose(p->pReal);
@@ -177041,6 +177112,9 @@ static int rbuVfsFileControl(sqlite3_file *pFile, int op, void *pArg){
       }else if( rc==SQLITE_NOTFOUND ){
         pRbu->pTargetFd = p;
         p->pRbu = pRbu;
+        if( p->openFlags & SQLITE_OPEN_MAIN_DB ){
+          rbuMainlistAdd(p);
+        }
         if( p->pWalFd ) p->pWalFd->pRbu = pRbu;
         rc = SQLITE_OK;
       }
@@ -177202,20 +177276,6 @@ static int rbuVfsShmUnmap(sqlite3_file *pFile, int delFlag){
   return rc;
 }
 
-/*
-** Given that zWal points to a buffer containing a wal file name passed to 
-** either the xOpen() or xAccess() VFS method, return a pointer to the
-** file-handle opened by the same database connection on the corresponding
-** database file.
-*/
-static rbu_file *rbuFindMaindb(rbu_vfs *pRbuVfs, const char *zWal){
-  rbu_file *pDb;
-  sqlite3_mutex_enter(pRbuVfs->mutex);
-  for(pDb=pRbuVfs->pMain; pDb && pDb->zWal!=zWal; pDb=pDb->pMainNext){}
-  sqlite3_mutex_leave(pRbuVfs->mutex);
-  return pDb;
-}
-
 /* 
 ** A main database named zName has just been opened. The following 
 ** function returns a pointer to a buffer owned by SQLite that contains
@@ -177294,7 +177354,7 @@ static int rbuVfsOpen(
       pFd->zWal = rbuMainToWal(zName, flags);
     }
     else if( flags & SQLITE_OPEN_WAL ){
-      rbu_file *pDb = rbuFindMaindb(pRbuVfs, zName);
+      rbu_file *pDb = rbuFindMaindb(pRbuVfs, zName, 0);
       if( pDb ){
         if( pDb->pRbu && pDb->pRbu->eStage==RBU_STAGE_OAL ){
           /* This call is to open a *-wal file. Intead, open the *-oal. This
@@ -177346,10 +177406,7 @@ static int rbuVfsOpen(
     ** mutex protected linked list of all such files.  */
     pFile->pMethods = &rbuvfs_io_methods;
     if( flags & SQLITE_OPEN_MAIN_DB ){
-      sqlite3_mutex_enter(pRbuVfs->mutex);
-      pFd->pMainNext = pRbuVfs->pMain;
-      pRbuVfs->pMain = pFd;
-      sqlite3_mutex_leave(pRbuVfs->mutex);
+      rbuMainlistAdd(pFd);
     }
   }else{
     sqlite3_free(pFd->zDel);
@@ -177397,7 +177454,7 @@ static int rbuVfsAccess(
   **      file opened instead.
   */
   if( rc==SQLITE_OK && flags==SQLITE_ACCESS_EXISTS ){
-    rbu_file *pDb = rbuFindMaindb(pRbuVfs, zPath);
+    rbu_file *pDb = rbuFindMaindb(pRbuVfs, zPath, 1);
     if( pDb && pDb->pRbu && pDb->pRbu->eStage==RBU_STAGE_OAL ){
       if( *pResOut ){
         rc = SQLITE_CANTOPEN;
@@ -203361,7 +203418,7 @@ static void fts5SourceIdFunc(
 ){
   assert( nArg==0 );
   UNUSED_PARAM2(nArg, apUnused);
-  sqlite3_result_text(pCtx, "fts5: 2018-01-22 18:45:57 0c55d179733b46d8d0ba4d88e01a25e10677046ee3da1d5b1581e86726f2171d", -1, SQLITE_TRANSIENT);
+  sqlite3_result_text(pCtx, "fts5: 2018-12-19 01:30:22 c255889bd95bd5430dc7ced3317011ae2abb483d6c9af883af3dc7d6c2c2f234", -1, SQLITE_TRANSIENT);
 }
 
 static int fts5Init(sqlite3 *db){
@@ -207629,9 +207686,9 @@ SQLITE_API int sqlite3_stmt_init(
 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_STMTVTAB) */
 
 /************** End of stmt.c ************************************************/
-#if __LINE__!=207604
+#if __LINE__!=207661
 #undef SQLITE_SOURCE_ID
-#define SQLITE_SOURCE_ID      "2018-01-22 18:45:57 0c55d179733b46d8d0ba4d88e01a25e10677046ee3da1d5b1581e86726f2alt2"
+#define SQLITE_SOURCE_ID      "2018-12-19 01:30:22 c255889bd95bd5430dc7ced3317011ae2abb483d6c9af883af3dc7d6c2c2alt2"
 #endif
 /* Return the source-id for this library */
 SQLITE_API const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
diff --git a/dist/sqlite3.h b/dist/sqlite3.h
index d8138b7..57669e1 100644
--- a/dist/sqlite3.h
+++ b/dist/sqlite3.h
@@ -125,7 +125,7 @@ extern "C" {
 */
 #define SQLITE_VERSION        "3.22.0"
 #define SQLITE_VERSION_NUMBER 3022000
-#define SQLITE_SOURCE_ID      "2018-01-22 18:45:57 0c55d179733b46d8d0ba4d88e01a25e10677046ee3da1d5b1581e86726f2171d"
+#define SQLITE_SOURCE_ID      "2018-12-19 01:30:22 c255889bd95bd5430dc7ced3317011ae2abb483d6c9af883af3dc7d6c2c2f234"
 
 /*
 ** CAPI3REF: Run-Time Library Version Numbers