Prevent the C++ test client from segfaulting when GPSD is not running.

C++ clients should test the return from the stream method to see if the
open succeeded.

2 files changed, 44 insertions, 38 deletions

diff --git a/libgpsmm.cpp b/libgpsmm.cpp
index 0dc20562..8df9af98 100644
--- a/libgpsmm.cpp
+++ b/libgpsmm.cpp
@@ -13,76 +13,79 @@
 
 struct gps_data_t* gpsmm::gps_inner_open(const char *host, const char *port) 
 {
-	const bool err = (gps_open(host, port, gps_state()) != 0);
-	if ( err ) {
-		return NULL;
-	}
-	else { // connection successfully opened
-		to_user= new struct gps_data_t;
-		return backup(); //we return the backup of our internal structure
-	}
+    const bool err = (gps_open(host, port, gps_state()) != 0);
+    if ( err ) {
+	to_user = NULL;
+	return NULL;
+    }
+    else { // connection successfully opened
+	to_user= new struct gps_data_t;
+	return backup(); //we return the backup of our internal structure
+    }
 }
 
 struct gps_data_t* gpsmm::stream(int flags) 
 {
-	if (gps_stream(gps_state(),flags, NULL)==-1) {
-		return NULL;
-	}
-	else {
-		return backup();
-	}
+    if (to_user == NULL)
+	return NULL;
+    else if (gps_stream(gps_state(),flags, NULL)==-1) {
+	return NULL;
+    }
+    else {
+	return backup();
+    }
 }
 
 struct gps_data_t* gpsmm::send(const char *request) 
 {
-	if (gps_send(gps_state(),request)==-1) {
-		return NULL;
-	}
-	else {
-		return backup();
-	}
+    if (gps_send(gps_state(),request)==-1) {
+	return NULL;
+    }
+    else {
+	return backup();
+    }
 }
 
 struct gps_data_t* gpsmm::read(void)
 {
-	if (gps_read(gps_state())<=0) {
-		// we return null if there was a read() error, if no
-		// data was ready in POLL_NOBLOCK mode, or if the
-		// connection is closed by gpsd
-		return NULL;
-	}
-	else {
-		return backup();
-	}
+    if (gps_read(gps_state())<=0) {
+	// we return null if there was a read() error, if no
+	// data was ready in POLL_NOBLOCK mode, or if the
+	// connection is closed by gpsd
+	return NULL;
+    }
+    else {
+	return backup();
+    }
 }
 
 bool gpsmm::waiting(int timeout)
 {
-  return gps_waiting(gps_state(), timeout);
+    return gps_waiting(gps_state(), timeout);
 }
 
 const char *gpsmm::data(void)
 {
-  return gps_data(gps_state());
+    return gps_data(gps_state());
 }
 
 void gpsmm::clear_fix(void)
 {
-	gps_clear_fix(&(gps_state()->fix));
+    gps_clear_fix(&(gps_state()->fix));
 }
 
 void gpsmm::enable_debug(int level, FILE *fp)
 {
 #ifdef CLIENTDEBUG_ENABLE
-	gps_enable_debug(level, fp);
+    gps_enable_debug(level, fp);
 #endif /* CLIENTDEBUG_ENABLE */
 }
 
 gpsmm::~gpsmm()
 {
-	if ( to_user != NULL ) {
-		gps_close(gps_state());
-		delete to_user;
-	}
+    if ( to_user != NULL ) {
+	gps_close(gps_state());
+	delete to_user;
+    }
 }
 #endif /* S_SPLINT_S */
diff --git a/test_gpsmm.cpp b/test_gpsmm.cpp
index f12de562..c95bf2b0 100644
--- a/test_gpsmm.cpp
+++ b/test_gpsmm.cpp
@@ -98,7 +98,10 @@ int main(void)
 {
     gpsmm gps_rec("localhost", DEFAULT_GPSD_PORT);
 
-    gps_rec.stream(WATCH_ENABLE|WATCH_JSON);
+    if (gps_rec.stream(WATCH_ENABLE|WATCH_JSON) == NULL) {
+        cerr << "No GPSD running.\n";
+        return 1;
+    }
 
     for (;;) {
 	struct gps_data_t* newdata;