bin/118292: Add support to remove all msg/shm/sem ids with ipcrm

[Edwin Groothuis]

Hello,

A friend of me has submitted this PR and I promised him that I would
see if I could get it implemented. I couldn't find anybody directly
responsible for the ips/iprcm tools, so I throw it in here for
discussion.

>Description:
    I've observed that linux apps running under the linuxulator
    have a habit of leaving behind shared memory segments which are
    unused, but which eventually cause the system to run out of
    free segments and these apps will stop working. ipcrm(1) currently
    only allows removal of unused message queues, shared memory
    segments and semaphores on an individual basis, or those having
    a matching (non-zero) key. However it would often be convenient
    to just do a complete cleanup of everything, usually as root.

    The attached patch allows removal of all message queues, shared
    memory segments or semaphores by specifying an id of -1 (ala
    kill(2)).  The code to lookup ids was taken from ipcs.

The patch is available in http://www.freebsd.org/cgi/query-pr.cgi?pr=118292

Edwin

-- 
Edwin Groothuis
edwin at freebsd.org
http://www.mavetju.org