gisi: Add checks for NULL

diff --git a/gisi/modem.c b/gisi/modem.c
index 3a0886b..8c9eb1d 100644 (file)
--- a/gisi/modem.c
+++ b/gisi/modem.c
@@ -502,14 +502,22 @@ GIsiModem *g_isi_modem_create_by_name(const char *name)
 
 void *g_isi_modem_set_userdata(GIsiModem *modem, void *data)
 {
-       void *old = modem->opaque;
+       void *old;
 
+       if (modem == NULL)
+               return NULL;
+
+       old = modem->opaque;
        modem->opaque = data;
+
        return old;
 }
 
 void *g_isi_modem_get_userdata(GIsiModem *modem)
 {
+       if (modem == NULL)
+               return NULL;
+
        return modem->opaque;
 }