Dear Bluez developers,
recently I have experienced a problem with one of my USB bluetooth
dongles: Whenever I plugged it into an USB port, the kernel detected
the device (i.e. reasonable output in dmesg) and the correct kernel
module (i.e. btusb) was loaded, but bluez frontends like
gnome-bluetooth could still not activate the device. The bug that I
reported against this software can be found at:
<https://bugzilla.gnome.org/show_bug.cgi?id=617050>.
It turned out that my USB dongle was the culprit, since it had an
invalid default device name that contained non-UTF-8 characters, as
reported by 'hciconfig -a'. When I changed the device name to
something reasonable via e.g. 'hciconfig hci0 name foobar', I had to
*restart* the bluetoothd daemon afterwards in order to get everything
working as expected. However, when I unplugged the USB dongle and
plugged it back in, the device name was reset to the defective default
again and I had to repeat this procedure.
Since I found it unreasonable to be forced to manually change the
device name and restart the daemon each and every time I plugged my
USB dongle in, I wanted a solution that detected a faulty device name
string during the device initialization phase and instantly fixed it
by writing a converted string back to the device. The attached patch
does exact this and makes my USB dongle work out-of-the-box, despite
its defective default device name.
Please review the patch for integration into Bluez.
Cheers,
Fabian
PS: There is still one open question that I would like to address:
Since I am going to print both the faulty and the fixed device name
strings to stderr via debug(), should I make sure the strings do not
contain any ASCII control characters prior to that? At least this is
what is done in tools/hciconfig.c:442.
--- bluez-4.64.orig/plugins/hciops.c
+++ bluez-4.64/plugins/hciops.c
@@ -119,6 +119,7 @@ static void init_device(int index)
struct hci_dev_info di;
pid_t pid;
int dd, err;
+ char name[249];
/* Do initialization in the separate process */
pid = fork();
@@ -143,6 +144,30 @@ static void init_device(int index)
exit(1);
}
+ if (hci_read_local_name(dd, sizeof(name), name, 1000) < 0) {
+ error("Can't read local name on hci%d: %s (%d)\n",
+ index, strerror(errno), errno);
+ exit(1);
+ }
+
+ name[248] = '\0';
+
+ if (!g_utf8_validate(name, -1, NULL)) {
+ char *utf8_name;
+
+ utf8_name = g_convert(name, -1, "UTF-8", "ISO-8859-1", NULL, NULL, NULL);
+ if (utf8_name) {
+ debug("Fix invalid non-UTF-8 device name \"%s\" on hci%d to \"%s\"",
+ name, index, utf8_name);
+ if (hci_write_local_name(dd, utf8_name, 2000) < 0) {
+ error("Can't change local name on hci%d: %s (%d)\n",
+ index, strerror(errno), errno);
+ exit(1);
+ }
+ g_free(utf8_name);
+ }
+ }
+
memset(&dr, 0, sizeof(dr));
dr.dev_id = index;
