Subject: Re: open(2) -> device open
To: Jay Parlar <>
From: David Laight <>
List: tech-kern
Date: 06/12/2003 13:56:13
On Thu, Jun 12, 2003 at 08:34:02AM -0400, Jay Parlar wrote:
> I'm currently trying to get familiar with parts of the NetBSD kernel, in 
> particular, the path taken from calling open() in userland on "/dev/xyz " to 
> arriving at the xyzopen() call in the device driver.
> I'm not having too much luck right now. I know enough to start with 
> sys_open() and go from there, but I keep getting lost in the internals.
> Would anyone be able to point me in the direction of a document that details 
> this path, or anything along those lines? Specifically, if someone could 
> tell me where the function pointer is assigned the interface methods of the 
> driver (i.e. the methods in cdevsw[]), and where the driver's open method is 
> called (through the function pointer).

You could always use ddb, set a breakpoint on sys_open() and single
step through.  You'll get to the driver fairly quickly...


David Laight: