Manager: Separate query and listen Dbus-connections.

Fix a race-condition where two threads might use the same dbus connection at
the same time.
Flush Dbus messages before statring the Dbus-thread. Initial Dbus messages are
buffered, and not handled until the first trigger to poll(). This will flush
these messages before starting the Dbus thread.

Signed-off-by: Sverre Vegge <sverre.vegge@stericsson.com>

1 files changed, 82 insertions, 50 deletions

diff --git a/u300-ril-manager.c b/u300-ril-manager.c
index bf4fe43..0a0649d 100644
--- a/u300-ril-manager.c
+++ b/u300-ril-manager.c
@@ -384,6 +384,44 @@ static void notifyForEvent(int index, short event)  {
          __func__, index);
 }
 
+static void flushDbusEvents(DBusConnection *dbcon)  {
+    DBusMessageIter args;
+    DBusMessage *dbmsg;
+    char *signame = NULL;
+    int res = 0;
+
+    for (;;) {
+        res = dbus_connection_get_dispatch_status(dbcon);
+        switch (res) {
+            case DBUS_DISPATCH_COMPLETE:
+                return;
+            case DBUS_DISPATCH_NEED_MEMORY:
+                LOGD("%s(): needs more memory. spinning.", __func__);
+                sleep(1);
+                break;
+            case DBUS_DISPATCH_DATA_REMAINS:
+                dbmsg = dbus_connection_pop_message(dbcon);
+                if (dbus_message_is_signal(dbmsg, "com.stericsson.mid.Modem",
+                                           "StateChange")) {
+                    if (!dbus_message_iter_init(dbmsg, &args)) {
+                        LOGD("%s(): Message has no arguments!", __func__);
+                    } else if (DBUS_TYPE_STRING !=
+                                dbus_message_iter_get_arg_type(&args)) {
+                        LOGD("%s(): Argument is not string!", __func__);
+                    } else {
+                        dbus_message_iter_get_basic(&args, &signame);
+                        LOGD("%s(): Flushing Signal with value \"%s\"",
+                                __func__, signame);
+                    }
+                }
+                break;
+            default:
+                /* This should not happen */
+                break;
+        }
+    }
+}
+
 static void processDbusEvent(DBusConnection *dbcon)  {
     int res = 0;
     for (;;) {
@@ -407,44 +445,6 @@ static void processDbusEvent(DBusConnection *dbcon)  {
     }
 }
 
-static int sendMsgToMidWithoutReply(DBusConnection *dbcon, char *msg)
-{
-    DBusError err;
-    DBusMessage *dbmsg;
-    int res = 0;
-
-    /* Initialize the dbus error return value */
-    dbus_error_init(&err);
-
-    dbmsg = dbus_message_new_method_call(DBUS_CONNECTION_NAME,
-                                         DBUS_OBJECT_PATH,
-                                         DBUS_OBJECT_INTERFACE,
-                                         msg);
-    if (dbmsg == NULL) {
-        LOGE("%s(): cannot create message", __func__);
-        res = -1;
-        goto finally1;
-    }
-
-    dbus_message_set_no_reply(dbmsg, TRUE);
-
-    if (!dbus_connection_send(dbcon, dbmsg, NULL)) {
-        LOGE("IPC message send error");
-        res =  -1;
-        goto finally2;
-    };
-
-    dbus_connection_flush(dbcon);
-
-finally2:
-    /* Drop reference count on the message */
-    dbus_message_unref(dbmsg);
-finally1:
-    dbus_error_free(&err);
-
-    return res;
-}
-
 static int requestMIDWithResponse(DBusConnection *dbcon,
                                     char *requestMethod,
                                     char *response)
@@ -565,10 +565,12 @@ static void *managerRunner(void *param)
 
 #ifndef EXTERNAL_MODEM_CONTROL_MODULE_DISABLED
     /*****************************************************
+     * Dbus-connection for listening:
      * Loop until we have connection to Dbus daemon      *
      *****************************************************/
     DBusError dbusErr;
-    DBusConnection *dbcon = NULL;
+    DBusConnection *listenDbcon = NULL;
+    DBusConnection *queryDbcon = NULL;
     bool dbusIsHere = false;
 
     /* Initial shutdown flag when Dbus enabled*/
@@ -577,18 +579,19 @@ static void *managerRunner(void *param)
     /* Connect to system dbus */
     do {
         dbus_error_init(&dbusErr);
-        dbcon = dbus_bus_get(DBUS_BUS_SYSTEM, &dbusErr);
+        listenDbcon = dbus_bus_get(DBUS_BUS_SYSTEM, &dbusErr);
 
-        if (!dbcon || dbus_error_is_set(&dbusErr)) {
-            LOGI("[DBUS]: connect to DBUS daemon returned error (%s).Will try"
-                    " again in %d second(s)", dbusErr.name, DBUS_CONNECT_DELAY);
+        if (!listenDbcon || dbus_error_is_set(&dbusErr)) {
+            LOGI("[DBUS]: connect to DBUS(listenDbcon) daemon returned error (%s)."
+                    "Will try again in %d second(s)",
+                    dbusErr.name, DBUS_CONNECT_DELAY);
             dbus_error_free(&dbusErr);
             sleep(DBUS_CONNECT_DELAY);
         } else
             dbusIsHere = true;
     } while (!dbusIsHere);
 
-    LOGI("[DBUS]: Connected to system dbus.");
+    LOGI("[DBUS]: listenDbcon Connected to system dbus.");
     ret = pthread_attr_init(&attr);
     if (ret != 0)
         LOGW("%s(): Failed to initialize dbus pthread attribute: %s",
@@ -600,9 +603,10 @@ static void *managerRunner(void *param)
              "attribute: %s", __func__, strerror(ret));
 
     /*************************************************
+     * Dbus-connection for listening:
      * Configure Dbus Connection.                    *
      *************************************************/
-    if (!dbus_connection_set_watch_functions(dbcon, addWatch,
+    if (!dbus_connection_set_watch_functions(listenDbcon, addWatch,
                      removeWatch, NULL, NULL, NULL)) {
         LOGE("%s(): dbus_connection_set_watch_functions failed.", __func__);
     }
@@ -613,7 +617,7 @@ static void *managerRunner(void *param)
      * Listen only signal from com.stericsson.mid.Modem interface (MID
      * state changes)
      */
-    dbus_bus_add_match(dbcon,
+    dbus_bus_add_match(listenDbcon,
         "type='signal', interface='com.stericsson.mid.Modem'", &dbusErr);
     if (dbus_error_is_set(&dbusErr)) {
         LOGE("%s(): DBUS match error %s: %s.", __func__,
@@ -622,21 +626,49 @@ static void *managerRunner(void *param)
     }
 
     /* Add a message filter to process incoming messages */
-    if (!dbus_connection_add_filter(dbcon,
+    if (!dbus_connection_add_filter(listenDbcon,
         (DBusHandleMessageFunction)midSignalHandler, NULL, NULL)) {
         LOGE("%s(): DBUS filter error.", __func__);
     }
 
+    /*****************************************************
+     * Dbus-connection for query:
+     * Loop until we have connection to Dbus daemon      *
+     *****************************************************/
+    dbusIsHere = false;
+    /* Connect to system dbus */
+    do {
+        dbus_error_init(&dbusErr);
+        queryDbcon = dbus_bus_get(DBUS_BUS_SYSTEM, &dbusErr);
+
+        if (!queryDbcon || dbus_error_is_set(&dbusErr)) {
+            LOGI("[DBUS]: connect to DBUS(queryDbcon) daemon returned error (%s)."
+                    "Will try again in %d second(s)",
+                    dbusErr.name, DBUS_CONNECT_DELAY);
+            dbus_error_free(&dbusErr);
+            sleep(DBUS_CONNECT_DELAY);
+        } else
+            dbusIsHere = true;
+    } while (!dbusIsHere);
+
+    LOGI("[DBUS]: queryDbcon Connected to system dbus.");
+
     /**********************************************************
      * Need to be sure CAIF interfaces are up. Wait for       *
      * "on" message, and release command threads immediately. *
      * ToDo: Add mutex, and wait for 'on' instead.            *
      **********************************************************/
-    while (!queryModemOn(dbcon))
+    while (!queryModemOn(queryDbcon))
         sleep(DBUS_CONNECT_DELAY);
 
+    /**
+     * Need to empty the listen-buffer initially.
+     * This must be done before we release command threads.
+     */
+    flushDbusEvents(listenDbcon);
+
     ret = pthread_create(&s_tid_dbusRunner, &attr,
-                             dbusAndThreadRunner, (void *)dbcon);
+                             dbusAndThreadRunner, (void *)listenDbcon);
     if (ret != 0) {
         LOGE("%s(): Failed to create dbus runner thread: %s. Asserting."
                 , __func__, strerror(ret));
@@ -742,7 +774,7 @@ static void *managerRunner(void *param)
 
         if (g_managerRelease) {
             /* Signal MID to restart Modem */
-            if (requestMIDWithResponse(dbcon, "Reboot", pResponse) == 0) {
+            if (requestMIDWithResponse(queryDbcon, "Reboot", pResponse) == 0) {
                 if (strncmp(pResponse, "OK", 2) == 0) {
                     LOGI("%s(): MID \"reboot\" request returned %s. "
                          "Modem restarting!", __func__, pResponse);