BUILDING-FOR-LINUX-2.4-KERNEL

Specific Instructions for a 2.4 Linux kernel
--------------------------------------------

Before using JACK in realtime mode with a 2.4 kernel, you may
need or want to take the following steps. A better choice is
to use a 2.6 kernel.

1) in /usr/src/linux/include/linux/capability.h find these lines

#define CAP_INIT_EFF_SET    to_cap_t(~0 & ~CAP_TO_MASK(CAP_SETPCAP))
#define CAP_INIT_INH_SET    to_cap_t(0)

   and change them to

#define CAP_INIT_EFF_SET    to_cap_t(~0)
#define CAP_INIT_INH_SET    to_cap_t(~0)

   then recompile your kernel and boot it.  (Note that the above lines
   are from linux 2.4.19; it may be different if you're using a
   different version)

   NB: This may expose your system to local denial of service attacks.
   If it is a shared system or server, you should assess the impact of
   enabling capabilities in the context of your overall system security
   requirements.

2) install libcap from
   ftp://ftp.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.4/

3) if you're using a journalling filesystem, mount some directory with
   -t tmpfs and use this with JACK's configure step as the
   argument to --with-default-tmpdir.

4) use --enable-capabilities with JACK's configure step