Fix segfaults due to erasing elements of the querries container in the inner loop

tools/dcdbquery/query.cpp

@@ -396,29 +396,34 @@ void DCDBQuery::prepareQuery(std::list<std::string> sensors, std::list<std::stri
 
 void DCDBQuery::execute() {
     std::string prevSensorName;
-    for (auto q: queries) {
-	if (q.first.name != prevSensorName) {
+    auto q = queries.begin();
+    while (q != queries.end()) {
+	if (q->first.name != prevSensorName) {
 	    // Find all queries for the same sensor
-	    std::pair<queryMap_t::iterator, queryMap_t::iterator> range = queries.equal_range(q.first);
+	    std::pair<queryMap_t::iterator, queryMap_t::iterator> range = queries.equal_range(q->first);
 	    
 	    /* Base scaling factor and unit of the public sensor */
-	    baseUnit = DCDB::UnitConv::fromString(q.first.unit);
-	    baseScalingFactor = q.first.scaling_factor;
+	    baseUnit = DCDB::UnitConv::fromString(q->first.unit);
+	    baseScalingFactor = q->first.scaling_factor;
 	    
 	    std::list<DCDB::SensorDataStoreReading> results;
-	    DCDB::Sensor sensor(connection, q.first);
+	    DCDB::Sensor sensor(connection, q->first);
 	    
 	    // Query aggregates first
 	    auto it=range.first;
-	    while(it!=range.second) {
+	    while(it!=range.second) {
 		if (it->second.aggregate != DCDB::AGGREGATE_NONE) {
 		    sensor.query(results, start_ts, end_ts, it->second.aggregate);
 		    if (results.size() > 0) {
 			genOutput(results, it, std::next(it));
 			results.clear();
+			// Remove the query from the list so it doesn't show up in the raw values below anymore
 			if (it == range.first) {
 			    range.first = std::next(it);
 			}
+			if (it == q) {
+			    q = std::next(q);
+			}
 			it = queries.erase(it);
 			continue;
 		    }
@@ -427,7 +432,7 @@ void DCDBQuery::execute() {
 	    }
 
 	    // Query raw values next
-	    for (auto it=range.first; it!=range.second; it++) {
+	    for (auto it=range.first; it!=range.second; it++) {
 		if (it->second.aggregate == DCDB::AGGREGATE_NONE) {
 		    sensor.query(results, start_ts, end_ts, DCDB::AGGREGATE_NONE);
 		    break;
@@ -439,8 +444,9 @@ void DCDBQuery::execute() {
 	    }
 
 
-	    prevSensorName = q.first.name;
+	    prevSensorName = q->first.name;
 	}
+	q++;
     }
 }