Testing and debugging STREAMS Drivers

Testing and debugging STREAMS Drivers

STREAMS drivers are debugged with the same tools and techniques used for other kernel-level drivers and discussed in ``Driver testing and debugging''. This section provides additional information about additional facilities that can be used to debug STREAMS modules and drivers. For information about additional testing tools that are available for MDI drivers, see ``Testing and debugging MDI drivers''.

The following topic is discussed:

``Using the crash command in STREAMS''

STREAMS modules and drivers can record trace messages using the strlog(D3str) function. Calls to this function are converted into STREAMS messages and relayed by log(7), a software driver, to the strace process. The log driver is also used to send error messages to the strerr process.

Module and driver writers should limit the number of messages sent to either the error or trace loggers. If a large number of messages are sent some could be lost, because some parts of this facility do not include flow control.

Messages may not be delivered to strace in the same order in which they were sent. However, every message includes a sequence number field provided to make it possible to determine the correct message order where necessary.