asTrap serverSpecific is dbChannel

Save/restore dbAddr::pfield around callbacks to
avoid corruption if CB forgets to restore.

Need to peak at dbChannel.h during libCom build.
So generate dbCoreAPI.h early, and add extra
-I to source location when compiling dbTrapWrite.c

modules/database/src/ioc/Makefile

@@ -16,7 +16,7 @@ USR_CPPFLAGS += -DUSE_TYPED_RSET -DUSE_TYPED_DSET
 # Shared library ABI version.
 SHRLIB_VERSION = $(EPICS_DATABASE_MAJOR_VERSION).$(EPICS_DATABASE_MINOR_VERSION).$(EPICS_DATABASE_MAINTENANCE_VERSION)
 
-API_HEADER = dbCoreAPI.h
+# dbCoreAPI.h generated earlier during libcom/
 dbCore_API = dbCore
 
 LIBRARY_IOC += dbCore

modules/libcom/src/Makefile

@@ -54,6 +54,8 @@ include $(LIBCOM)/yajl/Makefile
 # Generate library API header file
 API_HEADER = libComAPI.h
 Com_API = libCom
+# Generate early to allow a sneak peak at dbChannel.h
+API_HEADER += dbCoreAPI.h
 
 # Library to build:
 LIBRARY=Com

modules/libcom/src/as/Makefile

@@ -19,4 +19,8 @@ INC += asTrapWrite.h
 Com_SRCS += asLib.c
 Com_SRCS += asTrapWrite.c
 
+# Allow early access to dbChannel.h
+asTrapWrite_CPPFLAGS = -I$(LIBCOM)/../../database/src/ioc/db
+
+
 CLEANS += asLib.c asLib_lex.c

modules/libcom/src/as/asLib.h

@@ -22,6 +22,8 @@
 extern "C" {
 #endif
 
+struct dbChannel;
+
 /* 0 - Use (unverified) client provided host name string.
  * 1 - Use actual client IP address.  HAG() are resolved to IPs at ACF load time.
  */
@@ -121,7 +123,7 @@ LIBCOM_API int epicsStdCall asDumpHash(void);
 LIBCOM_API int epicsStdCall asDumpHashFP(FILE *fp);
 
 LIBCOM_API void * epicsStdCall asTrapWriteBeforeWithData(
-    const char *userid, const char *hostid, void *addr,
+    const char *userid, const char *hostid, struct dbChannel *addr,
     int dbrType, int no_elements, void *data);
 
 LIBCOM_API void epicsStdCall asTrapWriteAfterWrite(void *pvt);

modules/libcom/src/as/asTrapWrite.c

@@ -22,10 +22,10 @@
 
 #include "ellLib.h"
 #include "freeList.h"
-#include "epicsStdio.h"
 #include "cantProceed.h"
 #include "epicsMutex.h"
 #include "ellLib.h"
+#include <dbChannel.h>
 
 #include "asLib.h"
 #include "asTrapWrite.h"
@@ -112,11 +112,12 @@ void epicsStdCall asTrapWriteUnregisterListener(asTrapWriteId id)
 }
 
 void * epicsStdCall asTrapWriteBeforeWithData(
-    const char *userid, const char *hostid, void *addr,
+    const char *userid, const char *hostid, dbChannel *chan,
     int dbrType, int no_elements, void *data)
 {
     writeMessage *pwriteMessage;
     listener *plistener;
+    void *pfieldsave;
 
     if (pasTrapWritePvt == 0 ||
         ellCount(&pasTrapWritePvt->listenerList) <= 0) return 0;
@@ -125,13 +126,14 @@ void * epicsStdCall asTrapWriteBeforeWithData(
         pasTrapWritePvt->freeListWriteMessage);
     pwriteMessage->message.userid = userid;
     pwriteMessage->message.hostid = hostid;
-    pwriteMessage->message.serverSpecific = addr;
+    pwriteMessage->message.serverSpecific = chan;
     pwriteMessage->message.dbrType = dbrType;
     pwriteMessage->message.no_elements = no_elements;
     pwriteMessage->message.data = data;
     ellInit(&pwriteMessage->listenerPvtList);
 
     epicsMutexMustLock(pasTrapWritePvt->lock);
+    pfieldsave = chan->addr.pfield;
     ellAdd(&pasTrapWritePvt->writeMessageList, &pwriteMessage->node);
     plistener = (listener *)ellFirst(&pasTrapWritePvt->listenerList);
     while (plistener) {
@@ -141,6 +143,7 @@ void * epicsStdCall asTrapWriteBeforeWithData(
         plistenerPvt->plistener = plistener;
         pwriteMessage->message.userPvt = 0;
         plistener->func(&pwriteMessage->message, 0);
+        chan->addr.pfield = pfieldsave;
         plistenerPvt->userPvt = pwriteMessage->message.userPvt;
         ellAdd(&pwriteMessage->listenerPvtList, &plistenerPvt->node);
         plistener = (listener *)ellNext(&plistener->node);
@@ -153,18 +156,23 @@ void epicsStdCall asTrapWriteAfterWrite(void *pvt)
 {
     writeMessage *pwriteMessage = (writeMessage *)pvt;
     listenerPvt *plistenerPvt;
+    dbChannel *chan;
+    void *pfieldsave;
 
     if (pwriteMessage == 0 ||
         pasTrapWritePvt == 0) return;
 
     epicsMutexMustLock(pasTrapWritePvt->lock);
+    chan = pwriteMessage->message.serverSpecific;
+    pfieldsave = chan->addr.pfield;
     plistenerPvt = (listenerPvt *)ellFirst(&pwriteMessage->listenerPvtList);
     while (plistenerPvt) {
         listenerPvt *pnext = (listenerPvt *)ellNext(&plistenerPvt->node);
         listener *plistener = plistenerPvt->plistener;
 
         pwriteMessage->message.userPvt = plistenerPvt->userPvt;
         plistener->func(&pwriteMessage->message, 1);
+        chan->addr.pfield = pfieldsave;
         ellDelete(&pwriteMessage->listenerPvtList, &plistenerPvt->node);
         freeListFree(pasTrapWritePvt->freeListListenerPvt, plistenerPvt);
         plistenerPvt = pnext;

modules/libcom/src/as/asTrapWrite.h

@@ -26,6 +26,8 @@
 extern "C" {
 #endif
 
+struct dbChannel;
+
 /**
  * \brief The message passed to registered listeners.
  */
@@ -39,7 +41,7 @@ typedef struct asTrapWriteMessage {
      * the value the server provides to asTrapWriteWithData(), which
      * for RSRV is the dbChannel pointer for the target field.
      */
-    void *serverSpecific;
+    struct dbChannel *serverSpecific;
     /** \brief A field for use by the \ref asTrapWriteListener.
      *
      * When the listener is called before the write, this has the