[netflow-tools] patch for softflowd to be able to change privdrop chroot directory

[Hitoshi Irino]

Hello softflowd developers and users,

I commited (hg pushed) a patch for sfotflowd.
http://code.google.com/p/softflowd/source/detail?r=c6f1981395c887d4bae495cd3f5b0c4c2e4d79d7

This patchenable to change privdrop chroot direcotry for non BSD
environments.

The chroot dir was constant parameter in softflowd.h.
#ifndef PRIVDROP_CHROOT_DIR
# define PRIVDROP_CHROOT_DIR    "/var/empty"
#endif

"/var/empty" exists in (Open)BSD. On the other hand the directory does
not exist in (Ubuntu) Linux.

I added "--with-chrootdir" option in configure.ac. It is able to change
privdrop chroot directory.

If you want to change PRIVDROP_CHROOT_DIR to
"/var/run/softflowd/chroot", please type as follows :
"configure --with-chrootdir=/var/run/softflowd/chroot"

thanks,
Hitoshi Irino