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/
1:
s/suser/suser_xxx/
2:
Add new function: suser(struct proc *), prototyped in <sys/proc.h>.
3:
s/suser_xxx(\([a-zA-Z0-9_]*\)->p_ucred, \&\1->p_acflag)/suser(\1)/
The remaining suser_xxx() calls will be scrutinized and dealt with
later.
There may be some unneeded #include <sys/cred.h>, but they are left
as an exercise for Bruce.
More changes to the suser() API will come along with the "jail" code.
before mounting (should help to do not mount extended partitions:-).
Fixed problem with hanging while unmounting busy fs.
And (the most important) added some locks to prevent
simulaneous access to kernel structures!
cannot yet be closed, though.
I hope I got all credits right, and that the multiple submitted by lines
do not break anyone's scripts...
PR: kern/5038, kern/5567
Submitted by: Keith Jang <keith@email.gcn.net.tw>
Submitted by: Joachim Kuebart <joki@kuebart.stuttgart.netsurf.de>
Submitted by: Byung Yang <byung@wam.umd.edu>
Submitted by: Motomichi Matsuzaki <mzaki@e-mail.ne.jp>
unallocated parts of the last page when the file ended on a frag
but not a page boundary.
Delimitted by tags PRE_MATT_MMAP_EOF and POST_MATT_MMAP_EOF,
in files alpha/alpha/pmap.c i386/i386/pmap.c nfs/nfs_bio.c vm/pmap.h
vm/vm_page.c vm/vm_page.h vm/vnode_pager.c miscfs/specfs/spec_vnops.c
ufs/ufs/ufs_readwrite.c kern/vfs_bio.c
Submitted by: Matt Dillon <dillon@freebsd.org>
Reviewed by: Alan Cox <alc@freebsd.org>
This can have bad security implications, but the impact on FreeBSD
systems is minimal because this fs isn't in the default kernels and it
is unknown if it even works.
Submitted by: Manuel Bouyer <bouyer@antioche.eu.org> and
Artur Grabowski <art@stacken.kth.se>
Add d_parms() to {c,b}devsw[]. If non-NULL this function points to
a device routine that will properly fill in the specinfo structure.
vfs_subr.c's checkalias() supplies appropriate defaults. This change
should be fully backwards compatible with existing devices.
is the preparation step for moving pmap storage out of vmspace proper.
Reviewed by: Alan Cox <alc@cs.rice.edu>
Matthew Dillion <dillon@apollo.backplane.com>
attempt to optimize forks but were essentially given-up on due to
problems and replaced with an explicit dup of the vm_map_entry structure.
Prior to the removal, they were entirely unused.
c_caddr_t with extreme prejudice. Here we want to convert from
`const char *' to `const char *'. Casting through c_caddr_t is
not the way to do this. The original cast to caddr_t was apparently
to break warnings about const mismatches in other versions of BSD
(in 4.4BSDLite2, the conversion is from `const char *path' to
plain caddr_t).
changes to the VM system to support the new swapper, VM bug
fixes, several VM optimizations, and some additional revamping of the
VM code. The specific bug fixes will be documented with additional
forced commits. This commit is somewhat rough in regards to code
cleanup issues.
Reviewed by: "John S. Dyson" <root@dyson.iquest.net>, "David Greenman" <dg@root.com>
lock, and add some macros and function parameters to make sure that
the information get to the point where it can be put in the lock
structure.
While I'm here, add DEBUG_VFS_LOCKS to LINT.
is enough to satisfy things like StarOffice. This is a hack, but doing
it properly would be a LOT of work, and would require extensive grovelling
around in the user address space to find the argv[].
Obtained from: Mostly from Andrzej Bialecki <abial@nask.pl>.
Noticed by: Carl Mascott <cmascott@world.std.com>
Don't write access time of a file more than once per day. (Its precision is
1 day anyway). Don't try to write access and creation time in nonwin95 case.
Suggested by: bde (long time ago).
for possible buffer overflow problems. Replaced most sprintf()'s
with snprintf(); for others cases, added terminating NUL bytes where
appropriate, replaced constants like "16" with sizeof(), etc.
These changes include several bug fixes, but most changes are for
maintainability's sake. Any instance where it wasn't "immediately
obvious" that a buffer overflow could not occur was made safer.
Reviewed by: Bruce Evans <bde@zeta.org.au>
Reviewed by: Matthew Dillon <dillon@apollo.backplane.com>
Reviewed by: Mike Spengler <mks@networkcs.com>
Peter Wemm
Poul-Henning Kamp
Semen Ustimenko
Daniel C. Sobral
Julian Elischer
Dmitrij Tejblum
Warner Losh
Matthew Dillon
Luoqi Chen
John Polstra
Bruce Evans
Eivind Eklund
Archie Cobbs
Jordan K. Hubbard
Robert V. Baron