When enabled, this causes m_defrag to randomly return NULL (following
its normal failure case so that extra memory leaks are not introduced.)
Code similar to this was used to find / fix a few bugs last week.
to force the allocation of MAC labels for all mbufs regardless of
whether a configured policy requires labeling when the mbuf is
allocated. This can be useful it you anticipate loading a fully
labeled policy after boot and don't want mbufs to exist without
label storage, for performance measurement purposes, etc. It also
slightly lowers the overhead of m_tag labeling due to removing the
decision logic.
While here, improve commenting of other MAC options.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
returning some additional room in the first mbuf in a chain, and
avoiding feature-specific contents in the mbuf header. To do this:
- Modify mbuf_to_label() to extract the tag, returning NULL if not
found.
- Introduce mac_init_mbuf_tag() which does most of the work
mac_init_mbuf() used to do, except on an m_tag rather than an
mbuf.
- Scale back mac_init_mbuf() to perform m_tag allocation and invoke
mac_init_mbuf_tag().
- Replace mac_destroy_mbuf() with mac_destroy_mbuf_tag(), since
m_tag's are now GC'd deep in the m_tag/mbuf code rather than
at a higher level when mbufs are directly free()'d.
- Add mac_copy_mbuf_tag() to support m_copy_pkthdr() and related
notions.
- Generally change all references to mbuf labels so that they use
mbuf_to_label() rather than &mbuf->m_pkthdr.label. This
required no changes in the MAC policies (yay!).
- Tweak mbuf release routines to not call mac_destroy_mbuf(),
tag destruction takes care of it for us now.
- Remove MAC magic from m_copy_pkthdr() and m_move_pkthdr() --
the existing m_tag support does all this for us. Note that
we can no longer just zero the m_tag list on the target mbuf,
rather, we have to delete the chain because m_tag's will
already be hung off freshly allocated mbuf's.
- Tweak m_tag copying routines so that if we're copying a MAC
m_tag, we don't do a binary copy, rather, we initialize the
new storage and do a deep copy of the label.
- Remove use of MAC_FLAG_INITIALIZED in a few bizarre places
having to do with mbuf header copies previously.
- When an mbuf is copied in ip_input(), we no longer need to
explicitly copy the label because it will get handled by the
m_tag code now.
- No longer any weird handling of MAC labels in if_loop.c during
header copies.
- Add MPC_LOADTIME_FLAG_LABELMBUFS flag to Biba, MLS, mac_test.
In mac_test, handle the label==NULL case, since it can be
dynamically loaded.
In order to improve performance with this change, introduce the notion
of "lazy MAC label allocation" -- only allocate m_tag storage for MAC
labels if we're running with a policy that uses MAC labels on mbufs.
Policies declare this intent by setting the MPC_LOADTIME_FLAG_LABELMBUFS
flag in their load-time flags field during declaration. Note: this
opens up the possibility of post-boot policy modules getting back NULL
slot entries even though they have policy invariants of non-NULL slot
entries, as the policy might have been loaded after the mbuf was
allocated, leaving the mbuf without label storage. Policies that cannot
handle this case must be declared as NOTLATE, or must be modified.
- mac_labelmbufs holds the current cumulative status as to whether
any policies require mbuf labeling or not. This is updated whenever
the active policy set changes by the function mac_policy_updateflags().
The function iterates the list and checks whether any have the
flag set. Write access to this variable is protected by the policy
list; read access is currently not protected for performance reasons.
This might change if it causes problems.
- Add MAC_POLICY_LIST_ASSERT_EXCLUSIVE() to permit the flags update
function to assert appropriate locks.
- This makes allocation in mac_init_mbuf() conditional on the flag.
Reviewed by: sam
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
mbuf_to_label(). This permits the vast majority of entry point code
to be unaware that labels are stored in m->m_pkthdr.label, such that
we can experiment storage of labels elsewhere (such as in m_tags).
Reviewed by: sam
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
%f and sufficiently short %g specifiers where the precision was
explicitly zero, no '#' flag was specified, and the floating point
argument was > 0 and <= 0.5. While at it, add some comments to better
explain the relevant bits of code.
Noticed by: Christoph Kukulies <kuku@physik.rwth-aachen.de>
PCIM_CMD_MEMEN and PCIM_CMD_BUSMASTEREN, becaise some braindead
BIOSes (such as one found in my vprmatrix notebook) forget
to initialize it properly resulting in attachment failure.
Ignoring maxsegsz may lead to fatal data corruption for some devices.
ex. SBP-2/FireWire
We should apply this change to other platforms except for sparc64.
MFC after: 1 week
Always set the magic sequence when we write, rather than trusting the
previously read boot code to do so.
Use explicit encoding/decoding of little endian disk image.
Remove a comment which was OBE.
Change the test vector for "fdisk -I" to reflect that there is a magic
sequence in the result now.
Add test case for "fdisk" which reads the image back.
At least for the two test-cases this program now gives the same result
on sparc64 as on i386. The lack of an installed /boot/mbr on sparc64
raises an (un)interesting question.
the cpu dependent files. It will need to be done differently for USIII.
- Simplify the logic for detecting context rollovers. Instead of dealing
with it when the next context switch would cause the context numbers to
rollover, deal with it when they actually do rollover.
- Move some things around in cpu_switch so that we only do 1 membar #Sync
when switching address space, instead of 2.
- Detect kernel threads by comparing the new vm space to vmspace0, instead
if checking if the tlb context is 0.
- Removed some debug code.
