for weak references. GCC 4.2+ and Clang require static, older GCC wants
extern. Change __weak_reference to include sym. This requires changes
the existing users to not reuse the name of the symbol, but avoids
further differences between GCC 4.1 and GCC 4.2+/clang.
open for the fd. Prevents collision with rumphijack.
Also, prevent potential hyperspace memory access.
Does someone want to write tests for this facility?
be hijacked. If it's not specified, the default is
"path=/rump,socket=all:nolocal".
So, if you're moof and want to relive your domain/os days (??),
you can do this:
pain-rustique:51:~> setenv RUMPHIJACK 'path=//'
pain-rustique:52:~> df //dev
Filesystem 1K-blocks Used Avail %Cap Mounted on
rumpfs 1 1 0 100% /
pain-rustique:53:~> df /dev
Filesystem 1K-blocks Used Avail %Cap Mounted on
/dev/wd0a 1019864 280640 688232 28% /
where you can mount a file system with a userspace server *without*
it having to go through puffs.
Say, you first start a server with ffs capability and map a host
ffs image into it:
rump_server -lrumpvfs -lrumpfs_ffs \
-d key=/ffsimg,hostpath=ffs2.img,size=e unix:///tmp/ffsserv
Then, configure your shell to talk to the rump server:
setenv RUMP_SERVER unix:///tmp/ffsserv
setenv LD_PRELOAD /usr/lib/librumphijack.so
Create a mountpoint and mount the file system:
pain-rustique:60:~> sh
$ cd /rump
$ ls
dev
$ ls -l
total 1
drwxr-xr-x 2 root wheel 512 Feb 17 18:00 dev
$ mkdir mnt
$ mount_ffs /ffsimg /rump/mnt
mount_ffs: Warning: realpath /ffsimg: No such file or directory
$ df -h mnt
Filesystem Size Used Avail %Cap Mounted on
/ffsimg 496M 380M 91M 80% /mnt
$ du -sckh *
192K dev
380M mnt
381M total
$ umount -R mnt
$ df -h mnt
Filesystem Size Used Avail %Cap Mounted on
rumpfs 1.0K 1.0K 0B 100% /
$
(note, you need -R to umount due to various degrees of unsuccesful
magic it attempts to perform without it)
distinct file descriptors, but the rump kernel thinks they are both
the same. Now, if either one is closed by the application, "both"
will be closed in the rump kernel. To fix this, maintain an
alias-mask. It's not a perfect solution, though (consider e.g.
F_SETFL). Maybe we should actually dup the fd and maintain a
mapping table?
Also, prevent the host from opening file descriptors onto the places
in the fd namespace that have been dupped.
These together fix "cat < /rump/foo" in a hijacked /bin/sh.
(the first one makes sure stdin is open in cat and the second one
makes sure it doesn't try to cat something from /usr/share/locale
instead of stdin)
/rump are hijacked to go to the rump server. So you can e.g. start
a hijacked shell and cd to /rump:
$ cd /rump
$ pwd
/rump
$ ls -l dev/null
crwxr-xr-x 1 root wheel 2, 2 Feb 17 12:35 dev/null
$ ls -l /dev/null
crw-rw-rw- 1 root wheel 2, 2 Dec 22 2009 /dev/null
$ chmod 0 /dev/null
chmod: /dev/null: Operation not permitted
$ chmod 0 dev/null
$ ls -l /rump/dev/null
c--------- 1 root wheel 2, 2 Feb 17 12:35 /rump/dev/null
(of course the rump server must have vfs loaded for that to work)
while for some cases attempting retry after server restart works
brilliantly (e.g. firefox), in other cases it's quite disasterous
(sshd doesn't like its file descriptors going missing and does not
attempt to reopen them, leading to a quite catastophic loop of
EBADF once the server does come back)
* rename RUMPHIJACK_RETRY to the slightly more sensible
RUMPHIJACK_RETRYCONNECT
