tree b2f72e19e51d04c6f18398ca08f8b2e8519ee65e
parent 642c6d946b5cdc27d0146c41dc20b7c4d4c3ccd8
author Eric W. Biederman <ebiederm@xmission.com> 1257427601 -0800
committer Eric W. Biederman <ebiederm@xmission.com> 1257928925 -0800

sysctl: Reduce sys_sysctl to a compatibility wrapper around /proc/sys

To simply maintenance and to be able to remove all of the binary
sysctl support from various subsystems I have rewritten the binary
sysctl code as a compatibility wrapper around proc/sys.

The code is built around a hard coded table based on the table
in sysctl_check.c that lists all of our current binary sysctls
and provides enough information to convert from the sysctl
binary input into into ascii and back again.  New in this
patch is the realization that the only dynamic entries
that need to be handled have ifname as the asscii string
and ifindex as their ctl_name.

When a sys_sysctl is called the code now looks in the
translation table converting the binary name to the
path under /proc where the value is to be found.  Opens
that file, and calls into a format conversion wrapper
that calls fop->read and then fop->write as appropriate.

Since in practice the practically no one uses or tests
sys_sysctl rewritting the code to be beautiful is a little
silly.  The redeeming merit of this work is it allows us to
rip out all of the binary sysctl syscall support from
everywhere else in the tree.  Allowing us to remove
a lot of dead (after this patch) and barely maintained code.

In addition it becomes much easier to optimize the sysctl
implementation for being the backing store of /proc/sys,
without having to worry about sys_sysctl.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>