take a thread instead of a proc for their first argument.
- Add a mutex to protect the system-wide Linux osname, osrelease, and
oss_version variables.
- Change linux_get_prison() to take a thread instead of a proc for its
first argument and to use td_ucred rather than p_ucred. This is ok
because a thread's prison does not change even though it's ucred might.
- Also, change linux_get_prison() to return a struct prison * instead of
a struct linux_prison * since it returns with the struct prison locked
and this makes it easier to safely unlock the prison when we are done
messing with it.
mutable contents of struct prison (hostname, securelevel, refcount,
pr_linux, ...)
o Generally introduce mtx_lock()/mtx_unlock() calls throughout kern/
so as to enforce these protections, in particular, in kern_mib.c
protection sysctl access to the hostname and securelevel, as well as
kern_prot.c access to the securelevel for access control purposes.
o Rewrite linux emulator abstractions for accessing per-jail linux
mib entries (osname, osrelease, osversion) so that they don't return
a pointer to the text in the struct linux_prison, rather, a copy
to an array passed into the calls. Likewise, update linprocfs to
use these primitives.
o Update in_pcb.c to always use prison_getip() rather than directly
accessing struct prison.
Reviewed by: jhb
discussed on current.
The following variables are defined (for now):
osname (defaults to "Linux")
Allow users to change the name of the OS as returned by uname(2),
specially added for all those Linux Netscape users and statistics
maniacs :-) We now have what we all wanted!
osrelease (defaults to "2.2.5")
Allow users to change the version of the OS as returned by uname(2).
Since -current supports glibc2.1 now, change the default to 2.2.5
(was 2.0.36).
oss_version (defaults to 198144 [0x030600])
This one will be used by the OSS_GETVERSION ioctl (PR 12917) which I
can commit now that we have the MIB. The default version number is the
lowest version possible with the current 'encoding'.
A note about imprisoned processes (see jail(2)):
These variables are copy-on-write (as suggested by phk). This means that
imprisoned processes will use the system wide value unless it is written/set
by the process. From that moment on, a copy local to the prison will be
used.
A note about the implementation:
I choose to add a single pointer to struct prison, because I didn't like the
idea of changing struct prison every time I come up with a new variable. As
a side effect, the extra storage is only needed when a variable is set from
within the prison. This also minimizes kernel bloat when the Linuxulator is
not used; both compiled in or as a module.
Reviewed by: bde (first version only) and phk
