This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
before they got changed. This can help eliminate much of the
gymnastics drivers do in their ioctl routines to figure this out.
Remove commented out IFF_NOTRAILERS
to #include <sys/time.h> first. I've lost count of the number of times
I've had to patch this in porting code. The problem is the
"struct timeval ifi_lastchange" in the mib stats. (most other systems don't
have this, until 4.4bsd anyway).
it contains an address. This can replace all the myriad (wrong) ways
in which this task is performed in the current system. As an added
bonus, since it's a macro, then third-party software vendors have an easy
way to tell whether it's there or not. (This will become necessary
when sizeof(struct sockaddr) is increaased, and also when additional
fields are added to struct ifreq.)
Distribute all but the most fundamental malloc types. This time I also
remembered the trick to making things static: Put "static" in front of
them.
A couple of finer points by: bde
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
previous hackery involving struct in_ifaddr and arpcom. Get rid of the
abominable multi_kludge. Update all network interfaces to use the
new machanism. Distressingly few Ethernet drivers program the multicast
filter properly (assuming the hardware has one, which it usually does).
to TAILQs. Fix places which referenced these for no good reason
that I can see (the references remain, but were fixed to compile
again; they are still questionable).
type to be int so that errors can be returned.
2) Use the new SIOCSIFMTU ether_ioctl support in the few drivers that are
using ether_ioctl().
3) In if_fxp.c: treat if_bpf as a token, not as a pointer. Don't bother
testing for FXP_NTXSEG being reached in fxp_start()...just check for
non-NULL 'm'. Change fxp_ioctl() to use ether_ioctl().
<net/if_arp.h> and fixed the things that depended on it. The nested
include just allowed unportable programs to compile and made my
simple #include checking program report that networking code doesn't
need to include <sys/socket.h>.
interfaces. This creates two new tables in the net.link.generic branch
of the MIB; one contains (essentially) `ifdata' structures, and the other
contains a blob provided by the interface (and presumably used to
implement link-layer-specific MIB variables). A number of things
have been moved around in the `ifnet' and `ifdata' structures, so
NEW VERSIONS OF ifconfig(8) AND routed(8) ARE REQUIRED. (A simple
recompile is all that's necessary.)
I have a sample program which uses this interface for those interested
in making use of it.
The old system had the misfeature that the only policy it could implement
was tail-drop; the new IF_ENQ_DROP macro/function makes it possible
to implement more sophisticated queueing policies on a system-wide
basis. No code actually uses this yet (although on my machine
I have converted the ethernet and (polled) loopback to use it).
- fill in and use ifp->if_softc
- use if_bpf rather than private cookie variables
- change bpf interface to take advantage of this
- call ether_ifattach() directly from Ethernet drivers
- delete kludge in if_attach() that did this indirectly
of limited utility. In their place, add bunch of pointers
which will eventually be needed by the polled-interrupt scheme we're working
here. (It will probably be a while before the code is written and
committed here.) At the same time, a `void *if_softc' field
was added to the beginning of the structure to make certain driver
writers happier.
The practical upshot of all this is that you need to
recompile utilities such as netstat which manipulate struct ifnet.
Removed ifnet.if_init and ifnet.if_reset as they are generally unused.
Change the parameter passed to if_watchdog to be a ifnet * rather than
a unit number. All of this is an attempt to move toward not needing an
array of softc pointers (which is usually static in size) to point to
the driver softc.
if_ed.c:
Changed some of the argument passing to some functions to make a little
more sense.
if_ep.c, if_vx.c:
Killed completely bogus use of if_timer. It was being set in such a way
that the interface was being reset once per second (blech!).
and one set by the protocol family. Also add another parameter to
rtalloc1() to allow for any interface flags to be ignored; currently
this is only useful for RTF_PRCLONING. Get rid of rt_prflags and re-unite
with rt_flags. Add T/TCP ``route metrics''.
NB: YOU MUST RECOMPILE `route' AND OTHER RELATED PROGRAMS AS A RESULT OF
THIS CHANGE.
This also adds a new interface parameter, `ifi_physical', which will
eventually replace IFF_ALTPHYS as the mechanism for specifying the
particular physical connection desired on a multiple-connection card.
NB: YOU MUST RECOMPILE `ifconfig' AND OTHER RELATED PROGRAMS AS A RESULT OF
THIS CHANGE.
Declare a complete prototype for the function pointer *ifa_rtrequest.
radix.h:
Declare a complete prototype for the function pointer *rnh_walktree
and for the function rn_walktree.
Uniformize idempotency ifdef.
- Delete redundant declarations.
- Add -Wredundant-declarations to Makefile.i386 so they don't come back.
- Delete sloppy COMMON-style declarations of uninitialized data in
header files.
- Add a few prototypes.
- Clean up warnings resulting from the above.
NB: ioconf.c will still generate a redundant-declaration warning, which
is unavoidable unless somebody volunteers to make `config' smarter.
