- DTrace scripts to check for errors, performance, ...
they serve mostly as examples of what you can do with the static probe;s
with moderate load the scripts may be overwhelmed, excessive lock-tracing
may influence program behavior (see the last design decission)
Design decissions:
- use "linuxulator" as the provider for the native bitsize; add the
bitsize for the non-native emulation (e.g. "linuxuator32" on amd64)
- Add probes only for locks which are acquired in one function and released
in another function. Locks which are aquired and released in the same
function should be easy to pair in the code, inter-function
locking is more easy to verify in DTrace.
- Probes for locks should be fired after locking and before releasing to
prevent races (to provide data/function stability in DTrace, see the
man-page of "dtrace -v ..." and the corresponding DTrace docs).
The SYSCTL_NODE macro defines a list that stores all child-elements of
that node. If there's no SYSCTL_DECL macro anywhere else, there's no
reason why it shouldn't be static.
restrictions) were found to be inadequately described by a boolean.
Define a new parameter type with three values (disable, new, inherit)
to handle these and future cases.
Approved by: re (kib), bz (mentor)
Discussed with: rwatson
by creating a child jail, which is visible to that jail and to any
parent jails. Child jails may be restricted more than their parents,
but never less. Jail names reflect this hierarchy, being MIB-style
dot-separated strings.
Every thread now points to a jail, the default being prison0, which
contains information about the physical system. Prison0's root
directory is the same as rootvnode; its hostname is the same as the
global hostname, and its securelevel replaces the global securelevel.
Note that the variable "securelevel" has actually gone away, which
should not cause any problems for code that properly uses
securelevel_gt() and securelevel_ge().
Some jail-related permissions that were kept in global variables and
set via sysctls are now per-jail settings. The sysctls still exist for
backward compatibility, used only by the now-deprecated jail(2) system
call.
Approved by: bz (mentor)
designation of the emulated kernel version.
linux_kernver() returns integer value formatted as 'VVVMMMIII' where
VVV - version, MMM - major revision, III - minor revision.
Approved by: kib (mentor)
OSD-based jail extensions. This allows the Linux MIB to accessed via
jail_set and jail_get, and serves as a demonstration of adding jail support
to a module.
Reviewed by: dchagin, kib
Approved by: bz (mentor)
No need to lock prison in a case of linux_use26 because the int
setting is atomic and process cannot leave jail.
Submitted by: kib
Reviewed by: jhb
Requested by: rdivacky
Redo the checking for 2.6 emulation. We now cache the value of
use26 and replace calls to linux_get_osrelease() + parsing with
a call to linux_use26(). Typical path is lockless now.
Pointed out by: kib
This allows to ship RELENG_7_0 with a default osrelease of 2.4.2 and the
possibility to enable 2.6.x emulation without the possible performance
impact of the previous version of the check.
Submitted by: rdivacky
which existed to cleanup the linux_osname mutex. Now that MTX_SYSINIT()
has grown a SYSUNINIT to destroy mutexes on unload, the extra destroy here
was redundant and resulted in panics in debug kernels.
MFC after: 1 week
Reported by: Goran Gajic ggajic at afrodita dot rcub dot bg dot ac dot yu
on AMD64, and the general case where the emulated platform has different
size pointers than we use natively:
- declare certain structure members as l_uintptr_t and use the new PTRIN
and PTROUT macros to convert to and from native pointers.
- declare some structures __packed on amd64 when the layout would differ
from that used on i386.
- include <machine/../linux32/linux.h> instead of <machine/../linux/linux.h>
if compiling with COMPAT_LINUX32. This will need to be revisited before
32-bit and 64-bit Linux emulation support can coexist in the same kernel.
- other small scattered changes.
This should be a no-op on i386 and Alpha.
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
sysctl_req', which describes in-progress sysctl requests. This permits
sysctl handlers to have access to the current thread, permitting work
on implementing td->td_ucred, migration of suser() to using struct
thread to derive the appropriate ucred, and allowing struct thread to be
passed down to other code, such as network code where td is not currently
available (and curproc is used).
o Note: netncp and netsmb are not updated to reflect this change, as they
are not currently KSE-adapted.
Reviewed by: julian
Obtained from: TrustedBSD Project
o Introduce private types for use in linux syscalls for two reasons:
1. establish type independence for ease in porting and,
2. provide a visual queue as to which syscalls have proper
prototypes to further cleanup the i386/alpha split.
Linuxulator types are prefixed by 'l_'. void and char have not
been "virtualized".
o Provide dummy functions for all syscalls and remove dummy functions
or implementations of truely obsolete syscalls.
o Sanitize the shm*, sem* and msg* syscalls.
o Make a first attempt to implement the linux_sysctl syscall. At this
time it only returns one MIB (KERN_VERSION), but most importantly,
it tells us when we need to add additional sysctls :-)
o Bump the kenel version up to 2.4.2 (this is not the same as the
KERN_VERSION MIB, BTW).
o Implement new syscalls, of which most are specific to i386. Our
syscall table is now up to date with Linux 2.4.2. Some highlights:
- Implement the 32-bit uid_t and gid_t bases syscalls.
- Implement a couple of 64-bit file size/offset bases syscalls.
o Fix or improve numerous syscalls and prototypes.
o Reduce style(9) violations while I'm here. Especially indentation
inconsistencies within the same file are addressed. Re-indenting
did not obfuscate actual changes to the extend that it could not
be combined.
NOTE: I spend some time testing these changes and found that if there
were regressions, they were not caused by these changes AFAICT.
It was observed that installing a RH 7.1 runtime environment
did make matters worse. Hangs and/or reboots have been observed
with and without these changes, so when it failed to make life
better in cases it doesn't look like it made it worse.
credential structure, ucred (cr->cr_prison).
o Allow jail inheritence to be a function of credential inheritence.
o Abstract prison structure reference counting behind pr_hold() and
pr_free(), invoked by the similarly named credential reference
management functions, removing this code from per-ABI fork/exit code.
o Modify various jail() functions to use struct ucred arguments instead
of struct proc arguments.
o Introduce jailed() function to determine if a credential is jailed,
rather than directly checking pointers all over the place.
o Convert PRISON_CHECK() macro to prison_check() function.
o Move jail() function prototypes to jail.h.
o Emulate the P_JAILED flag in fill_kinfo_proc() and no longer set the
flag in the process flags field itself.
o Eliminate that "const" qualifier from suser/p_can/etc to reflect
mutex use.
Notes:
o Some further cleanup of the linux/jail code is still required.
o It's now possible to consider resolving some of the process vs
credential based permission checking confusion in the socket code.
o Mutex protection of struct prison is still not present, and is
required to protect the reference count plus some fields in the
structure.
Reviewed by: freebsd-arch
Obtained from: TrustedBSD Project
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
