Add fallback to simulation mode

Add logic to fall back to simulation mode in the absence of the CAN interface,
based on a modified form of the dropped changes from patch #2 of:

https://gerrit.automotivelinux.org/gerrit/#/c/7641

This should fix SPEC-383 by allowing the HVAC demo to run on setups without
the CAN hardware again.

Bug-AGL: SPEC-383

Change-Id: I3ee11c92baccde427986ceb077a37e9b9c900b11
Signed-off-by: Scott Murray <scott.murray@konsulko.com>

diff --git a/binding/hvac-demo-binding.c b/binding/hvac-demo-binding.c
index 3eb1876..1b776cd 100644 (file)
--- a/binding/hvac-demo-binding.c
+++ b/binding/hvac-demo-binding.c
@@ -1,7 +1,9 @@
 /*
  * Copyright (C) 2015, 2016 "IoT.bzh"
+ * Copyright (C) 2016 Konsulko Group
  * Author "Romain Forlot"
  * Author "Jose Bolo"
+ * Author "Scott Murray <scott.murray@konsulko.com>"
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +20,7 @@
 #define _GNU_SOURCE
 
 #include <string.h>
+#include <stdbool.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -31,9 +34,6 @@
 #include <afb/afb-binding.h>
 #include <afb/afb-service-itf.h>
 
-// Uncomment this line to pass into can simulation mode
-//#define SIMULATE_HVAC
-
 #define CAN_DEV "vcan0"
 
 static const struct afb_binding_interface *interface;
@@ -94,18 +94,15 @@ static struct {
 
 struct can_handler {
        int socket;
+       bool simulation;
+       char *send_msg;
        struct sockaddr_can txAddress;
 };
 
-static struct can_handler can_handler = { .socket = -1 };
+static struct can_handler can_handler = { .socket = -1, .simulation = false, .send_msg = "SENDING CAN FRAME"};
 
-static int open_can_dev()
+static int open_can_dev_helper()
 {
-#if defined(SIMULATE_HVAC)
-       DEBUG(interface, "Defining can handler socket to 0 and return");
-       can_handler.socket = 0;
-       return 0;
-#else
        struct ifreq ifr;
 
        DEBUG(interface, "CAN Handler socket : %d", can_handler.socket);
@@ -142,7 +139,20 @@ static int open_can_dev()
                can_handler.socket = -1;
        }
        return -1;
-#endif
+}
+
+static int open_can_dev()
+{
+       int rc = retry(open_can_dev_helper);
+       if(rc < 0)
+       {
+               ERROR(interface, "Open of interface %s failed. Falling back to simulation mode", CAN_DEV);
+               can_handler.socket = 0;
+               can_handler.simulation = true;
+               can_handler.send_msg = "FAKE CAN FRAME";
+               rc = 0;
+       }
+       return rc;
 }
 
 // Get original get temperature function from cpp hvacplugin code
@@ -198,29 +208,25 @@ static int write_can()
                txCanFrame.data[7] = 0;
 
                DEBUG(interface, "%s: %d %d [%02x %02x %02x %02x %02x %02x %02x %02x]\n",
-#if defined(SIMULATE_HVAC)
-                       "FAKE CAN FRAME",
-#else
-                       "SENDING CAN FRAME",
-#endif
+                       can_handler.send_msg,
                        txCanFrame.can_id, txCanFrame.can_dlc,
                        txCanFrame.data[0], txCanFrame.data[1], txCanFrame.data[2], txCanFrame.data[3],
                        txCanFrame.data[4], txCanFrame.data[5], txCanFrame.data[6], txCanFrame.data[7]);
 
-#if !defined(SIMULATE_HVAC)
-               rc = sendto(can_handler.socket, &txCanFrame, sizeof(struct can_frame), 0,
-                       (struct sockaddr*)&can_handler.txAddress, sizeof(can_handler.txAddress));
-               if (rc < 0)
+               if(!can_handler.simulation)
                {
-                       ERROR(interface, "Sending can frame failed. Attempt to reopen can device socket.");
-                       retry(open_can_dev);
+                       rc = sendto(can_handler.socket, &txCanFrame, sizeof(struct can_frame), 0,
+                                   (struct sockaddr*)&can_handler.txAddress, sizeof(can_handler.txAddress));
+                       if (rc < 0)
+                       {
+                               ERROR(interface, "Sending CAN frame failed.");
+                       }
                }
-#endif
        }
        else
        {
                ERROR(interface, "socket not initialized. Attempt to reopen can device socket.");
-               retry(open_can_dev);
+               open_can_dev();
        }
        return rc;
 }
@@ -425,5 +431,5 @@ const struct afb_binding *afbBindingV1Register (const struct afb_binding_interfa
 
 int afbBindingV1ServiceInit(struct afb_service service)
 {
-       return retry(open_can_dev);
+       return open_can_dev();
 }