Hi,
On Wed, Dec 10, 2008 at 03:18:39AM +0100, Sascha Wessel wrote:
> I guess it's a problem with invalid ubx headers. Can you try the
> attached patch?
argh, forgot to check the buffer length, corrected patch attached...
Greetings,
Sascha
diff --git a/framework/subsystems/ogpsd/ubx.py b/framework/subsystems/ogpsd/ubx.py
index 0dbad8e..1ab1dff 100644
--- a/framework/subsystems/ogpsd/ubx.py
+++ b/framework/subsystems/ogpsd/ubx.py
@@ -320,29 +320,40 @@ class UBXDevice( GPSDevice ):
def parse( self, data ):
self.buffer += data
+ buffer_offset = 0
# Minimum packet length is 8
- while len(self.buffer) >= 8:
+ while len(self.buffer) >= buffer_offset + 8:
# Find the beginning of a UBX message
- start = self.buffer.find( chr( SYNC1 ) + chr( SYNC2 ) )
- if start > 0 or (start == -1 and len(self.buffer) > 1):
+ start = self.buffer.find( chr( SYNC1 ) + chr( SYNC2 ), buffer_offset )
+
+ if buffer_offset == 0 and start != 0:
logger.debug( "Discarded data not UBX %s" % repr(self.buffer[:start]) )
self.buffer = self.buffer[start:]
continue
- (cl, id, length) = struct.unpack("<xxBBH", self.buffer[:6])
- if len(self.buffer) < length + 8:
+ if start == -1 or start + 8 > len(self.buffer):
return
- if self.checksum(self.buffer[2:length+6]) != struct.unpack("<BB", self.buffer[length+6:length+8]):
- logger.warning( "UBX packed class 0x%x, id 0x%x, length %i failed checksum" % (cl, id, length) )
- self.buffer = self.buffer[2:]
+ (cl, id, length) = struct.unpack("<BBH", self.buffer[start+2:start+6])
+ if len(self.buffer) < start + length + 8:
+ buffer_offset = start + 2
+ continue
+
+ if self.checksum(self.buffer[start+2:start+length+6]) != struct.unpack("<BB", self.buffer[start+length+6:start+length+8]):
+ buffer_offset = start + 2
+ continue
+
+ if start != 0:
+ logger.warning(" UBX packet ignored %s" % repr(self.buffer[:start]) )
+ self.buffer = self.buffer[start:]
+ buffer_offset = 0
continue
- # Now we got a valid UBX packet, decode it
- self.decode(cl, id, length, self.buffer[6:length+6])
+ self.decode(cl, id, length, self.buffer[start+6:start+length+6])
# Discard packet
- self.buffer = self.buffer[length+8:]
+ self.buffer = self.buffer[start+length+8:]
+ buffer_offset = 0
def send( self, clid, length, payload ):
logger.debug( "Sending UBX packet of type %s: %s" % ( clid, payload ) )
_______________________________________________
Smartphones-userland mailing list
Smartphones-userland@linuxtogo.org
http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/smartphones-userland
