gatchat: Print error message if opening tun failes

This is a very common mistake. Let's help the users to
configure their system correctly.

diff --git a/gatchat/ppp_net.c b/gatchat/ppp_net.c
index 1609b99..813ed9b 100644 (file)
--- a/gatchat/ppp_net.c
+++ b/gatchat/ppp_net.c
@@ -155,8 +155,12 @@ struct ppp_net *ppp_net_new(GAtPPP *ppp, int fd)
        if (fd < 0) {
                /* open a tun interface */
                fd = open("/dev/net/tun", O_RDWR);
-               if (fd < 0)
+               if (fd < 0) {
+                       ppp_debug(ppp, "Couldn't open tun device. "
+                                       "Do you run oFono as root and do you "
+                                       "have the TUN module loaded?");
                        goto error;
+               }
 
                ifr.ifr_flags = IFF_TUN | IFF_NO_PI;
                strcpy(ifr.ifr_name, "ppp%d");