get_array_info() can modifiy DBADDR::pfield

Allow the record support function get_array_info()
to modify its first argument to provide a different
pointer from which values should be read.

Remember the original and restore it afterwards.

src/ioc/db/dbAccess.c

@@ -780,6 +780,7 @@ long dbGet(DBADDR *paddr, short dbrType,
     void *pbuffer, long *options, long *nRequest, void *pflin)
 {
     char *pbuf = pbuffer;
+    void *pfieldsave;
     db_field_log *pfl = (db_field_log *)pflin;
     short field_type;
     long no_elements;
@@ -815,6 +816,13 @@ long dbGet(DBADDR *paddr, short dbrType,
         return S_db_badDbrtype;
     }
 
+    /* For array field, the rset function
+     * get_array_info() is allowed to modify
+     * paddr->pfield.  So we store the original
+     * value and restore it later.
+     */
+    pfieldsave = paddr->pfield;
+
     /* check for array */
     if ((!pfl || pfl->type == dbfl_type_rec) &&
         paddr->special == SPC_DBADDR &&
@@ -860,7 +868,8 @@ long dbGet(DBADDR *paddr, short dbrType,
             sprintf(message, "dbGet: Missing conversion for [%d][%d]\n",
                     field_type, dbrType);
             recGblDbaddrError(S_db_badDbrtype, paddr, message);
-            return S_db_badDbrtype;
+            status = S_db_badDbrtype;
+            goto done;
         }
         /* convert database field  and place it in the buffer */
         if (n <= 0) {
@@ -880,6 +889,8 @@ long dbGet(DBADDR *paddr, short dbrType,
             status = convert(&localAddr, pbuf, n, no_elements, offset);
         }
     }
+done:
+    paddr->pfield = pfieldsave;
     return status;
 }
 

src/std/filters/arr.c

@@ -104,7 +104,9 @@ static db_field_log* filter(void* pvt, dbChannel *chan, db_field_log *pfl) {
         if (chan->addr.special == SPC_DBADDR &&
             nSource > 1 &&
             (prset = dbGetRset(&chan->addr)) &&
-            prset->get_array_info) {
+            prset->get_array_info)
+        {
+            void *pfieldsave = chan->addr.pfield;
             prec = dbChannelRecord(chan);
             dbScanLock(prec);
             prset->get_array_info(&chan->addr, &nSource, &offset);
@@ -126,6 +128,7 @@ static db_field_log* filter(void* pvt, dbChannel *chan, db_field_log *pfl) {
                 pfl->u.r.field = pdst;
             }
             dbScanUnlock(prec);
+            chan->addr.pfield = pfieldsave;
         }
 
     /* Extract from buffer */