What keeps drivers/base/sys.c sysdev_show() from overrunning buffer?

What keeps drivers/base/sys.c sysdev_show() from overrunning buffer?

[Paul Jackson]

The calls in drivers/base/sys.c to sysdev_show(), which seem to resolve
to the routines node_read_cpumap() and node_read_meminfo() in node.c,
do not take any buffer count (size).  They used to, by Patrick removed
the count parameter in Jan 2003, from here and other such places.

What's to keep the node_read_*() sprintf's from overrunning these
buffers?

I am developing some changes to the cpumask_t print routines, which
include using snprintf() instead of sprintf(), and watching buffer
limits.  These changes are motivated by the need to handle such things
as 512 CPUs.

I couldn't plug my new routine into read_cpumap() to display the
node_dev->cpumap (a cpumask_t), for want of a buffer count.

-- 
                          I won't rest till it's the best ...
                          Programmer, Linux Scalability
                          Paul Jackson <pj@sgi.com> 1.650.933.1373

Re: What keeps drivers/base/sys.c sysdev_show() from overrunning buffer?

[William Lee Irwin III]

On Thu, Nov 20, 2003 at 03:52:11PM -0800, Paul Jackson wrote:
> The calls in drivers/base/sys.c to sysdev_show(), which seem to resolve
> to the routines node_read_cpumap() and node_read_meminfo() in node.c,
> do not take any buffer count (size).  They used to, by Patrick removed
> the count parameter in Jan 2003, from here and other such places.
> What's to keep the node_read_*() sprintf's from overrunning these
> buffers?
> I am developing some changes to the cpumask_t print routines, which
> include using snprintf() instead of sprintf(), and watching buffer
> limits.  These changes are motivated by the need to handle such things
> as 512 CPUs.
> I couldn't plug my new routine into read_cpumap() to display the
> node_dev->cpumap (a cpumask_t), for want of a buffer count.

There was some infrastructure erected for this at one point (seq_file);
I wonder why it's not using that. But yes, this needs to get taken
care of one way or another.


-- wli