db: lock record for db_create_read_log() and dbChannelGetField()

since 27fe3e4 db_create_read_log()
accesses record fields.

remove now redundant db_create_read_log() calls.

modules/database/src/ioc/db/dbChannel.c

@@ -635,9 +635,21 @@ long dbChannelGetField(dbChannel *chan, short dbrType, void *pbuffer,
 {
     dbCommon *precord = chan->addr.precord;
     long status = 0;
+    unsigned char local_fl = 0;
 
     dbScanLock(precord);
+    if (!pfl && (ellCount(&chan->pre_chain) || ellCount(&chan->post_chain))) {
+        pfl = db_create_read_log(chan);
+        if (pfl) {
+            local_fl = 1;
+            pfl = dbChannelRunPreChain(chan, pfl);
+            pfl = dbChannelRunPostChain(chan, pfl);
+        }
+    }
     status = dbChannelGet(chan, dbrType, pbuffer, options, nRequest, pfl);
+    if (local_fl) {
+        db_delete_field_log(pfl);
+    }
     dbScanUnlock(precord);
     return status;
 }

modules/database/src/ioc/db/dbChannel.h

@@ -511,6 +511,10 @@ DBCORE_API long dbChannelGet(dbChannel *chan, short type,
  * \param[in,out] nRequest Pointer to the element count.
  * \param[in] pfl Pointer to a db_field_log or NULL.
  * \returns 0, or an error status value.
+ *
+ * \since UNRELEASED If pfl is NULL and chan has filters, db_create_read_log() will be called
+ *        internally to create a temporary db_field_log which is passed to dbChannelGet()
+ *        then deallocated.
  */
 DBCORE_API long dbChannelGetField(dbChannel *chan, short type,
         void *pbuffer, long *options, long *nRequest, void *pfl);

modules/database/src/ioc/db/dbUnitTest.c

@@ -202,7 +202,6 @@ void testdbGetFieldEqual(const char* pv, int dbrType, ...)
 void testdbVGetFieldEqual(const char* pv, short dbrType, va_list ap)
 {
     dbChannel *chan = dbChannelCreate(pv);
-    db_field_log *pfl = NULL;
     long nReq = 1;
     union anybuf pod;
     long status = S_dbLib_recNotFound;
@@ -212,18 +211,7 @@ void testdbVGetFieldEqual(const char* pv, short dbrType, va_list ap)
         goto done;
     }
 
-    if(ellCount(&chan->filters)) {
-        pfl = db_create_read_log(chan);
-        if (!pfl) {
-            testFail("can't db_create_read_log w/ %s", pv);
-            goto done;
-        }
-
-        pfl = dbChannelRunPreChain(chan, pfl);
-        pfl = dbChannelRunPostChain(chan, pfl);
-    }
-
-    status = dbChannelGetField(chan, dbrType, pod.bytes, NULL, &nReq, pfl);
+    status = dbChannelGetField(chan, dbrType, pod.bytes, NULL, &nReq, NULL);
     if (status) {
         testFail("dbGetField(\"%s\", %d, ...) -> %#lx (%s)", pv, dbrType, status, errSymMsg(status));
         goto done;
@@ -261,7 +249,6 @@ void testdbVGetFieldEqual(const char* pv, short dbrType, va_list ap)
     }
 
 done:
-    db_delete_field_log(pfl);
     if(chan)
         dbChannelDelete(chan);
 }
@@ -288,7 +275,6 @@ void testdbPutArrFieldOk(const char* pv, short dbrType, unsigned long count, con
 void testdbGetArrFieldEqual(const char* pv, short dbfType, long nRequest, unsigned long cnt, const void *pbufraw)
 {
     dbChannel *chan = dbChannelCreate(pv);
-    db_field_log *pfl = NULL;
     const long vSize = dbValueSize(dbfType);
     const long nStore = vSize * nRequest;
     long status = S_dbLib_recNotFound;
@@ -300,24 +286,13 @@ void testdbGetArrFieldEqual(const char* pv, short dbfType, long nRequest, unsign
         goto done;
     }
 
-    if(ellCount(&chan->filters)) {
-        pfl = db_create_read_log(chan);
-        if (!pfl) {
-            testFail("can't db_create_read_log w/ %s", pv);
-            goto done;
-        }
-
-        pfl = dbChannelRunPreChain(chan, pfl);
-        pfl = dbChannelRunPostChain(chan, pfl);
-    }
-
     gbuf = gstore = malloc(nStore);
     if(!gbuf && nStore!=0) { /* note that malloc(0) is allowed to return NULL on success */
         testFail("Allocation failed esize=%ld total=%ld", vSize, nStore);
         return;
     }
 
-    status = dbChannelGetField(chan, dbfType, gbuf, NULL, &nRequest, pfl);
+    status = dbChannelGetField(chan, dbfType, gbuf, NULL, &nRequest, NULL);
     if (status) {
         testFail("dbGetField(\"%s\", %d, ...) -> %#lx", pv, dbfType, status);
 

modules/database/src/ioc/db/db_access.c

@@ -148,6 +148,7 @@ int dbChannel_get_count(
     long options;
     long i;
     long zero = 0;
+    unsigned char local_fl = 0;
 
    /* The order of the DBR* elements in the "newSt" structures below is
     * very important and must correspond to the order of processing
@@ -156,6 +157,16 @@ int dbChannel_get_count(
 
     dbScanLock(dbChannelRecord(chan));
 
+    /* If filters are involved in a read, create field log and run filters */
+    if (!pfl && (ellCount(&chan->pre_chain) || ellCount(&chan->post_chain))) {
+        pfl = db_create_read_log(chan);
+        if (pfl) {
+            local_fl = 1;
+            pfl = dbChannelRunPreChain(chan, pfl);
+            pfl = dbChannelRunPostChain(chan, pfl);
+        }
+    }
+
     switch(buffer_type) {
     case(oldDBR_STRING):
         status = dbChannelGet(chan, DBR_STRING, pbuffer, &zero, nRequest, pfl);
@@ -800,6 +811,8 @@ int dbChannel_get_count(
 
     dbScanUnlock(dbChannelRecord(chan));
 
+    if (local_fl) db_delete_field_log(pfl);
+
     if (status) return -1;
     return 0;
 }

modules/database/src/ioc/rsrv/camessage.c

@@ -493,7 +493,6 @@ static void read_reply ( void *pArg, struct dbChannel *dbch,
     const int readAccess = asCheckGet ( pciu->asClientPVT );
     int status;
     int autosize;
-    int local_fl = 0;
     long item_count;
     ca_uint32_t payload_size;
     dbAddr *paddr=&dbch->addr;
@@ -535,21 +534,9 @@ static void read_reply ( void *pArg, struct dbChannel *dbch,
         return;
     }
 
-    /* If filters are involved in a read, create field log and run filters */
-    if (!pfl && (ellCount(&dbch->pre_chain) || ellCount(&dbch->post_chain))) {
-        pfl = db_create_read_log(dbch);
-        if (pfl) {
-            local_fl = 1;
-            pfl = dbChannelRunPreChain(dbch, pfl);
-            pfl = dbChannelRunPostChain(dbch, pfl);
-        }
-    }
-
     status = dbChannel_get_count ( dbch, pevext->msg.m_dataType,
                   pPayload, &item_count, pfl);
 
-    if (local_fl) db_delete_field_log(pfl);
-
     if ( status < 0 ) {
         /* Clients recv the status of the operation directly to the
          * event/put/get callback.  (from CA_V41())
@@ -616,7 +603,6 @@ static int read_action ( caHdrLargeArray *mp, void *pPayloadIn, struct client *p
     ca_uint32_t payloadSize;
     void *pPayload;
     int status;
-    int local_fl = 0;
     db_field_log *pfl = NULL;
 
     if ( ! pciu ) {
@@ -655,21 +641,9 @@ static int read_action ( caHdrLargeArray *mp, void *pPayloadIn, struct client *p
         return RSRV_OK;
     }
 
-    /* If filters are involved in a read, create field log and run filters */
-    if (ellCount(&pciu->dbch->pre_chain) || ellCount(&pciu->dbch->post_chain)) {
-        pfl = db_create_read_log(pciu->dbch);
-        if (pfl) {
-            local_fl = 1;
-            pfl = dbChannelRunPreChain(pciu->dbch, pfl);
-            pfl = dbChannelRunPostChain(pciu->dbch, pfl);
-        }
-    }
-
     status = dbChannel_get ( pciu->dbch, mp->m_dataType,
                   pPayload, mp->m_count, pfl );
 
-    if (local_fl) db_delete_field_log(pfl);
-
     if ( status < 0 ) {
         send_err ( mp, ECA_GETFAIL, pClient, RECORD_NAME ( pciu->dbch ) );
         SEND_UNLOCK ( pClient );

modules/database/test/ioc/db/dbChArrTest.cpp

@@ -130,9 +130,11 @@ static void check(short dbr_type) {
     off = Offset; req = 10; \
     memset(buf, 0, sizeof(buf)); \
     (void) dbPutField(&offaddr, DBR_LONG, &off, 1); \
+    dbScanLock(dbChannelRecord(pch)); \
     pfl = db_create_read_log(pch); \
     testOk(pfl && pfl->type == dbfl_type_ref, "Valid pfl, type = ref"); \
-    testOk(!dbChannelGetField(pch, DBR_LONG, buf, NULL, &req, pfl), "Got Field value"); \
+    testOk(!dbChannelGet(pch, DBR_LONG, buf, NULL, &req, pfl), "Got Field value"); \
+    dbScanUnlock(dbChannelRecord(pch)); \
     testOk(req == Size, "Got %ld elements (expected %d)", req, Size); \
     if (!testOk(!memcmp(buf, Expected, sizeof(Expected)), "Data correct")) \
         for (i=0; i<Size; i++) \
@@ -174,14 +176,16 @@ static void check(short dbr_type) {
     off = Offset; req = 15; \
     memset(buf, 0, sizeof(buf)); \
     (void) dbPutField(&offaddr, DBR_LONG, &off, 1); \
+    dbScanLock(dbChannelRecord(pch)); \
     pfl = db_create_read_log(pch); \
     pfl->type = dbfl_type_ref; \
     pfl->field_type = DBF_CHAR; \
     pfl->field_size = 1; \
     pfl->no_elements = 26; \
     pfl->dtor = freeArray; \
     pfl->u.r.field = epicsStrDup("abcdefghijklmnopqrsstuvwxyz"); \
-    testOk(!dbChannelGetField(pch, DBR_LONG, buf, NULL, &req, pfl), "Got Field value"); \
+    testOk(!dbChannelGet(pch, DBR_LONG, buf, NULL, &req, pfl), "Got Field value"); \
+    dbScanUnlock(dbChannelRecord(pch)); \
     testOk(req == Size, "Got %ld elements (expected %d)", req, Size); \
     if (!testOk(!memcmp(buf, Expected, sizeof(Expected)), "Data correct")) \
         for (i=0; i<Size; i++) \