Commit Graph

76 Commits

Author SHA1 Message Date
Robert Watson
fefd0ac8a9 Remove 'uio' argument from MAC Framework and MAC policy entry points for
extended attribute get/set; in the case of get an uninitialized user
buffer was passed before the EA was retrieved, making it of relatively
little use; the latter was simply unused by any policies.

Obtained from:	TrustedBSD Project
Sponsored by:	Google, Inc.
2009-03-08 12:32:06 +00:00
Robert Watson
9162f64b58 Rather than having MAC policies explicitly declare what object types
they label, derive that information implicitly from the set of label
initializers in their policy operations set.  This avoids a possible
class of programmer errors, while retaining the structure that
allows us to avoid allocating labels for objects that don't need
them.  As before, we regenerate a global mask of labeled objects
each time a policy is loaded or unloaded, stored in mac_labeled.

Discussed with:   csjp
Suggested by:     Jacques Vidrine <nectar at apple.com>
Obtained from:    TrustedBSD Project
Sponsored by:     Apple, Inc.
2009-01-10 10:58:41 +00:00
Robert Watson
dbdcb99498 Use MPC_OBJECT_IP6Q to indicate labeling of struct ip6q rather than
MPC_OBJECT_IPQ; it was already defined, just not used.

Obtained from:	TrustedBSD Project
Sponsored by:	Apple, Inc.
2009-01-10 09:17:16 +00:00
Edward Tomasz Napierala
15bc6b2bd8 Introduce accmode_t. This is required for NFSv4 ACLs - it will be neccessary
to add more V* constants, and the variables changed by this patch were often
being assigned to mode_t variables, which is 16 bit.

Approved by:	rwatson (mentor)
2008-10-28 13:44:11 +00:00
Robert Watson
9215889d21 Rename mac_cred_mmapped_drop_perms(), which revokes access to virtual
memory mappings when the MAC label on a process changes, to
mac_proc_vm_revoke(),

It now also acquires its own credential reference directly from the
affected process rather than accepting one passed by the the caller,
simplifying the API and consumer code.

Obtained from:	TrustedBSD Project
2008-10-28 12:49:07 +00:00
Robert Watson
212ab0cfb3 Rename three MAC entry points from _proc_ to _cred_ to reflect the fact
that they operate directly on credentials: mac_proc_create_swapper(),
mac_proc_create_init(), and mac_proc_associate_nfsd().  Update policies.

Obtained from:	TrustedBSD Project
2008-10-28 11:33:06 +00:00
Robert Watson
048e1287fa Implement MAC policy support for IPv6 fragment reassembly queues,
modeled on IPv4 fragment reassembly queue support.

Obtained from:	TrustedBSD Project
2008-10-26 22:46:37 +00:00
Dag-Erling Smørgrav
1ede983cc9 Retire the MALLOC and FREE macros. They are an abomination unto style(9).
MFC after:	3 months
2008-10-23 15:53:51 +00:00
Bjoern A. Zeeb
7fb179ba7e Add a mac_inpcb_check_visible implementation to all MAC policies
that handle mac_socket_check_visible.

Reviewed by:	rwatson
MFC after:	3 months (set timer; decide then)
2008-10-17 15:11:12 +00:00
Attilio Rao
0359a12ead Decontextualize the couplet VOP_GETATTR / VOP_SETATTR as the passed thread
was always curthread and totally unuseful.

Tested by: Giovanni Trematerra <giovanni dot trematerra at gmail dot com>
2008-08-28 15:23:18 +00:00
Robert Watson
6356dba0b4 Introduce two related changes to the TrustedBSD MAC Framework:
(1) Abstract interpreter vnode labeling in execve(2) and mac_execve(2)
    so that the general exec code isn't aware of the details of
    allocating, copying, and freeing labels, rather, simply passes in
    a void pointer to start and stop functions that will be used by
    the framework.  This change will be MFC'd.

(2) Introduce a new flags field to the MAC_POLICY_SET(9) interface
    allowing policies to declare which types of objects require label
    allocation, initialization, and destruction, and define a set of
    flags covering various supported object types (MPC_OBJECT_PROC,
    MPC_OBJECT_VNODE, MPC_OBJECT_INPCB, ...).  This change reduces the
    overhead of compiling the MAC Framework into the kernel if policies
    aren't loaded, or if policies require labels on only a small number
    or even no object types.  Each time a policy is loaded or unloaded,
    we recalculate a mask of labeled object types across all policies
    present in the system.  Eliminate MAC_ALWAYS_LABEL_MBUF option as it
    is no longer required.

MFC after:	1 week ((1) only)
Reviewed by:	csjp
Obtained from:	TrustedBSD Project
Sponsored by:	Apple, Inc.
2008-08-23 15:26:36 +00:00
Robert Watson
95b85ca3a9 Minor style tweaks. 2008-08-02 22:30:51 +00:00
Robert Watson
37f44cb428 The TrustedBSD MAC Framework named struct ipq instances 'ipq', which is the
same as the global variable defined in ip_input.c.  Instead, adopt the name
'q' as found in about 1/2 of uses in ip_input.c, preventing a collision on
the name.  This is non-harmful, but means that search and replace on the
global works less well (as in the virtualization work), as well as indexing
tools.

MFC after:	1 week
Reported by:	julian
2008-06-13 22:14:15 +00:00
Robert Watson
eb320b0ee7 Resort TrustedBSD MAC Framework policy entry point implementations and
declarations to match the object, operation sort order in the framework
itself.

Obtained from:	TrustedBSD Project
2007-10-29 13:33:06 +00:00
Robert Watson
2a9e17ce8e Garbage collect mac_mbuf_create_multicast_encap TrustedBSD MAC Framework
entry point, which is no longer required now that we don't support
old-style multicast tunnels.  This removes the last mbuf object class
entry point that isn't init/copy/destroy.

Obtained from:	TrustedBSD Project
2007-10-28 17:55:57 +00:00
Robert Watson
a13e21f7bc Continue to move from generic network entry points in the TrustedBSD MAC
Framework by moving from mac_mbuf_create_netlayer() to more specific
entry points for specific network services:

- mac_netinet_firewall_reply() to be used when replying to in-bound TCP
  segments in pf and ipfw (etc).

- Rename mac_netinet_icmp_reply() to mac_netinet_icmp_replyinplace() and
  add mac_netinet_icmp_reply(), reflecting that in some cases we overwrite
  a label in place, but in others we apply the label to a new mbuf.

Obtained from:	TrustedBSD Project
2007-10-28 17:12:48 +00:00
Robert Watson
b9b0dac33b Move towards more explicit support for various network protocol stacks
in the TrustedBSD MAC Framework:

- Add mac_atalk.c and add explicit entry point mac_netatalk_aarp_send()
  for AARP packet labeling, rather than using a generic link layer
  entry point.

- Add mac_inet6.c and add explicit entry point mac_netinet6_nd6_send()
  for ND6 packet labeling, rather than using a generic link layer entry
  point.

- Add expliict entry point mac_netinet_arp_send() for ARP packet
  labeling, and mac_netinet_igmp_send() for IGMP packet labeling,
  rather than using a generic link layer entry point.

- Remove previous genering link layer entry point,
  mac_mbuf_create_linklayer() as it is no longer used.

- Add implementations of new entry points to various policies, largely
  by replicating the existing link layer entry point for them; remove
  old link layer entry point implementation.

- Make MAC_IFNET_LOCK(), MAC_IFNET_UNLOCK(), and mac_ifnet_mtx global
  to the MAC Framework rather than static to mac_net.c as it is now
  needed outside of mac_net.c.

Obtained from:	TrustedBSD Project
2007-10-28 15:55:23 +00:00
Robert Watson
8640764682 Rename 'mac_mbuf_create_from_firewall' to 'mac_netinet_firewall_send' as
we move towards netinet as a pseudo-object for the MAC Framework.

Rename 'mac_create_mbuf_linklayer' to 'mac_mbuf_create_linklayer' to
reflect general object-first ordering preference.

Sponsored by:	SPARTA (original patches against Mac OS X)
Obtained from:	TrustedBSD Project, Apple Computer
2007-10-26 13:18:38 +00:00
Robert Watson
02be6269c3 Normalize TCP syncache-related MAC Framework entry points to match most
other entry points in the form mac_<object>_method().

Discussed with:	csjp
Obtained from:	TrustedBSD Project
2007-10-25 14:37:37 +00:00
Robert Watson
3f1a7a9086 Consistently name functions for mac_<policy> as <policy>_whatever rather
than mac_<policy>_whatever, as this shortens the names and makes the code
a bit easier to read.

When dealing with label structures, name variables 'mb', 'ml', 'mm rather
than the longer 'mac_biba', 'mac_lomac', and 'mac_mls', likewise making
the code a little easier to read.

Obtained from:	TrustedBSD Project
2007-10-25 11:31:11 +00:00
Robert Watson
a7f3aac7cb Further MAC Framework cleanup: normalize some local variable names and
clean up some comments.

Obtained from:	TrustedBSD Project
2007-10-25 07:49:47 +00:00
Robert Watson
30d239bc4c Merge first in a series of TrustedBSD MAC Framework KPI changes
from Mac OS X Leopard--rationalize naming for entry points to
the following general forms:

  mac_<object>_<method/action>
  mac_<object>_check_<method/action>

The previous naming scheme was inconsistent and mostly
reversed from the new scheme.  Also, make object types more
consistent and remove spaces from object types that contain
multiple parts ("posix_sem" -> "posixsem") to make mechanical
parsing easier.  Introduce a new "netinet" object type for
certain IPv4/IPv6-related methods.  Also simplify, slightly,
some entry point names.

All MAC policy modules will need to be recompiled, and modules
not updates as part of this commit will need to be modified to
conform to the new KPI.

Sponsored by:	SPARTA (original patches against Mac OS X)
Obtained from:	TrustedBSD Project, Apple Computer
2007-10-24 19:04:04 +00:00
Jeff Roberson
b61ce5b0e6 - Move all of the PS_ flags into either p_flag or td_flags.
- p_sflag was mostly protected by PROC_LOCK rather than the PROC_SLOCK or
   previously the sched_lock.  These bugs have existed for some time.
 - Allow swapout to try each thread in a process individually and then
   swapin the whole process if any of these fail.  This allows us to move
   most scheduler related swap flags into td_flags.
 - Keep ki_sflag for backwards compat but change all in source tools to
   use the new and more correct location of P_INMEM.

Reported by:	pho
Reviewed by:	attilio, kib
Approved by:	re (kensmith)
2007-09-17 05:31:39 +00:00
Robert Watson
45e0f3d63d Rename mac_check_vnode_delete() MAC Framework and MAC Policy entry
point to mac_check_vnode_unlink(), reflecting UNIX naming conventions.

This is the first of several commits to synchronize the MAC Framework
in FreeBSD 7.0 with the MAC Framework as it will appear in Mac OS X
Leopard.

Reveiwed by:    csjp, Samy Bahra <sbahra at gwu dot edu>
Submitted by:   Jacques Vidrine <nectar at apple dot com>
Obtained from:  Apple Computer, Inc.
Sponsored by:   SPARTA, SPAWAR
Approved by:    re (bmah)
2007-09-10 00:00:18 +00:00
Jeff Roberson
982d11f836 Commit 14/14 of sched_lock decomposition.
- Use thread_lock() rather than sched_lock for per-thread scheduling
   sychronization.
 - Use the per-process spinlock rather than the sched_lock for per-process
   scheduling synchronization.

Tested by:      kris, current@
Tested on:      i386, amd64, ULE, 4BSD, libthr, libkse, PREEMPTION, etc.
Discussed with: kris, attilio, kmacy, jhb, julian, bde (small parts each)
2007-06-05 00:00:57 +00:00
Robert Watson
305759909e Rename mac*devfsdirent*() to mac*devfs*() to synchronize with SEDarwin,
where similar data structures exist to support devfs and the MAC
Framework, but are named differently.

Obtained from:	TrustedBSD Project
Sponsored by:	SPARTA, Inc.
2007-04-23 13:36:54 +00:00
Robert Watson
78007886c9 Apply variable name normalization to MAC policies: adopt global conventions
for the naming of variables associated with specific data structures.

Obtained from:	TrustedBSD Project
2007-04-23 13:15:23 +00:00
Robert Watson
eb542415c0 In the MAC Framework implementation, file systems have two per-mountpoint
labels: the mount label (label of the mountpoint) and the fs label (label
of the file system).  In practice, policies appear to only ever use one,
and the distinction is not helpful.

Combine mnt_mntlabel and mnt_fslabel into a single mnt_label, and
eliminate extra machinery required to maintain the additional label.
Update policies to reflect removal of extra entry points and label.

Obtained from:	TrustedBSD Project
Sponsored by:	SPARTA, Inc.
2007-04-22 16:18:10 +00:00
Robert Watson
c14d15ae3e Remove MAC Framework access control check entry points made redundant with
the introduction of priv(9) and MAC Framework entry points for privilege
checking/granting.  These entry points exactly aligned with privileges and
provided no additional security context:

- mac_check_sysarch_ioperm()
- mac_check_kld_unload()
- mac_check_settime()
- mac_check_system_nfsd()

Add mpo_priv_check() implementations to Biba and LOMAC policies, which,
for each privilege, determine if they can be granted to processes
considered unprivileged by those two policies.  These mostly, but not
entirely, align with the set of privileges granted in jails.

Obtained from:	TrustedBSD Project
2007-04-22 15:31:22 +00:00
Robert Watson
18717f69b1 Allow MAC policy modules to control access to audit configuration system
calls.  Add MAC Framework entry points and MAC policy entry points for
audit(), auditctl(), auditon(), setaudit(), aud setauid().

MAC Framework entry points are only added for audit system calls where
additional argument context may be useful for policy decision-making; other
audit system calls without arguments may be controlled via the priv(9)
entry points.

Update various policy modules to implement audit-related checks, and in
some cases, other missing system-related checks.

Obtained from:	TrustedBSD Project
Sponsored by:	SPARTA, Inc.
2007-04-21 22:08:48 +00:00
Robert Watson
0142affc77 Introduce accessor functions mac_label_get() and mac_label_set() to replace
LABEL_TO_SLOT() macro used by policy modules to query and set label data
in struct label.  Instead of using a union, store an intptr_t, simplifying
the API.

Update policies: in most cases this required only small tweaks to current
wrapper macros.  In two cases, a single wrapper macros had to be split into
separate get and set macros.

Move struct label definition from _label.h to mac_internal.h and remove
_label.h.  With this change, policies may now treat struct label * as
opaque, allowing us to change the layout of struct label without breaking
the policy module ABI.  For example, we could make the maximum number of
policies with labels modifiable at boot-time rather than just at
compile-time.

Obtained from:	TrustedBSD Project
2007-02-06 14:19:25 +00:00
Robert Watson
0efd6615cd Move src/sys/sys/mac_policy.h, the kernel interface between the MAC
Framework and security modules, to src/sys/security/mac/mac_policy.h,
completing the removal of kernel-only MAC Framework include files from
src/sys/sys.  Update the MAC Framework and MAC policy modules.  Delete
the old mac_policy.h.

Third party policy modules will need similar updating.

Obtained from:	TrustedBSD Project
2006-12-22 23:34:47 +00:00
Christian S.J. Peron
430fc7560a Teach the MAC policies which utilize mbuf labeling the new syncache
entry points.  Properly initialize the mbuf label based on the label
we copy from the PCB. This fixes an LOR between the PCB and syncache
code.
2006-12-13 06:03:22 +00:00
Robert Watson
acd3428b7d Sweep kernel replacing suser(9) calls with priv(9) calls, assigning
specific privilege names to a broad range of privileges.  These may
require some future tweaking.

Sponsored by:           nCircle Network Security, Inc.
Obtained from:          TrustedBSD Project
Discussed on:           arch@
Reviewed (at least in part) by: mlaier, jmg, pjd, bde, ceri,
                        Alex Lyashkov <umka at sevcity dot net>,
                        Skip Ford <skip dot ford at verizon dot net>,
                        Antoine Brodin <antoine dot brodin at laposte dot net>
2006-11-06 13:42:10 +00:00
Robert Watson
aed5570872 Complete break-out of sys/sys/mac.h into sys/security/mac/mac_framework.h
begun with a repo-copy of mac.h to mac_framework.h.  sys/mac.h now
contains the userspace and user<->kernel API and definitions, with all
in-kernel interfaces moved to mac_framework.h, which is now included
across most of the kernel instead.

This change is the first step in a larger cleanup and sweep of MAC
Framework interfaces in the kernel, and will not be MFC'd.

Obtained from:	TrustedBSD Project
Sponsored by:	SPARTA
2006-10-22 11:52:19 +00:00
Christian S.J. Peron
d94f2a68f8 Introduce a new entry point, mac_create_mbuf_from_firewall. This entry point
exists to allow the mandatory access control policy to properly initialize
mbufs generated by the firewall. An example where this might happen is keep
alive packets, or ICMP error packets in response to other packets.

This takes care of kernel panics associated with un-initialize mbuf labels
when the firewall generates packets.

[1] I modified this patch from it's original version, the initial patch
    introduced a number of entry points which were programmatically
    equivalent. So I introduced only one. Instead, we should leverage
    mac_create_mbuf_netlayer() which is used for similar situations,
    an example being icmp_error()

    This will minimize the impact associated with the MFC

Submitted by:	mlaier [1]
MFC after:	1 week

This is a RELENG_6 candidate
2006-09-12 04:25:13 +00:00
Robert Watson
5bb84bc84b Normalize a significant number of kernel malloc type names:
- Prefer '_' to ' ', as it results in more easily parsed results in
  memory monitoring tools such as vmstat.

- Remove punctuation that is incompatible with using memory type names
  as file names, such as '/' characters.

- Disambiguate some collisions by adding subsystem prefixes to some
  memory types.

- Generally prefer lower case to upper case.

- If the same type is defined in multiple architecture directories,
  attempt to use the same name in additional cases.

Not all instances were caught in this change, so more work is required to
finish this conversion.  Similar changes are required for UMA zone names.
2005-10-31 15:41:29 +00:00
Poul-Henning Kamp
3642298923 Add #include <sys/sx.h>, devfs is going to require this shortly. 2005-09-19 18:52:51 +00:00
Robert Watson
223aaaecb0 Remove mac_create_root_mount() and mpo_create_root_mount(), which
provided access to the root file system before the start of the
init process.  This was used briefly by SEBSD before it knew about
preloading data in the loader, and using that method to gain
access to data earlier results in fewer inconsistencies in the
approach.  Policy modules still have access to the root file system
creation event through the mac_create_mount() entry point.

Removed now, and will be removed from RELENG_6, in order to gain
third party policy dependencies on the entry point for the lifetime
of the 6.x branch.

MFC after:	3 days
Submitted by:	Chris Vance <Christopher dot Vance at SPARTA dot com>
Sponsored by:	SPARTA
2005-09-19 13:59:57 +00:00
Robert Watson
d26dd2d99e When devfs cloning takes place, provide access to the credential of the
process that caused the clone event to take place for the device driver
creating the device.  This allows cloned device drivers to adapt the
device node based on security aspects of the process, such as the uid,
gid, and MAC label.

- Add a cred reference to struct cdev, so that when a device node is
  instantiated as a vnode, the cloning credential can be exposed to
  MAC.

- Add make_dev_cred(), a version of make_dev() that additionally
  accepts the credential to stick in the struct cdev.  Implement it and
  make_dev() in terms of a back-end make_dev_credv().

- Add a new event handler, dev_clone_cred, which can be registered to
  receive the credential instead of dev_clone, if desired.

- Modify the MAC entry point mac_create_devfs_device() to accept an
  optional credential pointer (may be NULL), so that MAC policies can
  inspect and act on the label or other elements of the credential
  when initializing the skeleton device protections.

- Modify tty_pty.c to register clone_dev_cred and invoke make_dev_cred(),
  so that the pty clone credential is exposed to the MAC Framework.

While currently primarily focussed on MAC policies, this change is also
a prerequisite for changes to allow ptys to be instantiated with the UID
of the process looking up the pty.  This requires further changes to the
pty driver -- in particular, to immediately recycle pty nodes on last
close so that the credential-related state can be recreated on next
lookup.

Submitted by:	Andrew Reisse <andrew.reisse@sparta.com>
Obtained from:	TrustedBSD Project
Sponsored by:	SPAWAR, SPARTA
MFC after:	1 week
MFC note:	Merge to 6.x, but not 5.x for ABI reasons
2005-07-14 10:22:09 +00:00
Robert Watson
3c308b091f Eliminate MAC entry point mac_create_mbuf_from_mbuf(), which is
redundant with respect to existing mbuf copy label routines.  Expose
a new mac_copy_mbuf() routine at the top end of the Framework and
use that; use the existing mpo_copy_mbuf_label() routine on the
bottom end.

Obtained from:	TrustedBSD Project
Sponsored by:	SPARTA, SPAWAR
Approved by:	re (scottl)
2005-07-05 23:39:51 +00:00
Christian S.J. Peron
c92163dcad Move MAC check_vnode_mmap entry point out from being exclusive to
MAP_SHARED so that the entry point gets executed un-conditionally.
This may be useful for security policies which want to perform access
control checks around run-time linking.

-add the mmap(2) flags argument to the check_vnode_mmap entry point
 so that we can make access control decisions based on the type of
 mapped object.
-update any dependent API around this parameter addition such as
 function prototype modifications, entry point parameter additions
 and the inclusion of sys/mman.h header file.
-Change the MLS, BIBA and LOMAC security policies so that subject
 domination routines are not executed unless the type of mapping is
 shared. This is done to maintain compatibility between the old
 vm_mmap_vnode(9) and these policies.

Reviewed by:	rwatson
MFC after:	1 month
2005-04-14 16:03:30 +00:00
Robert Watson
c77cf2b162 Remove policy references to mpo_check_vnode_mprotect(), which is
currently unimplemented.

Update copyrights.

Pointed out by:	csjp
2005-01-26 23:43:32 +00:00
Robert Watson
20e3484680 Remove an obsoleted comment about struct versions.
MFC after:	3 days
Pointed out by:	trhodes
2005-01-23 14:26:09 +00:00
Alexander Kabaev
1477f58850 Introduce SLOT_SET macro and use it in place of casts as lvalues. 2004-07-28 07:01:33 +00:00
Robert Watson
2220907b6e Introduce a temporary mutex, mac_ifnet_mtx, to lock MAC labels on
network interfaces.  This global mutex will protect all ifnet labels.
Acquire the mutex across various MAC activities on interfaces, such
as security checks, propagating interface labels to mbufs generated
from the interface, retrieving and setting the interface label.

Introduce mpo_copy_ifnet_label MAC policy entry point to copy the
value of an interface label from one label to another.  Use this
to avoid performing a label externalize while holding mac_ifnet_mtx;
copy the label to a temporary ifnet label and then externalize that.

Implement mpo_copy_ifnet_label for various MAC policies that
implement interface labeling using generic label copying routines.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, McAfee Research
2004-06-24 03:34:46 +00:00
Poul-Henning Kamp
89c9c53da0 Do the dreaded s/dev_t/struct cdev */
Bump __FreeBSD_version accordingly.
2004-06-16 09:47:26 +00:00
Pawel Jakub Dawidek
63dba32b76 Reimplement sysctls handling by MAC framework.
Now I believe it is done in the right way.

Removed some XXMAC cases, we now assume 'high' integrity level for all
sysctls, except those with CTLFLAG_ANYBODY flag set. No more magic.

Reviewed by:	rwatson
Approved by:	rwatson, scottl (mentor)
Tested with:	LINT (compilation), mac_biba(4) (functionality)
2004-02-22 12:31:44 +00:00
Robert Watson
f6a4109212 Update my personal copyrights and NETA copyrights in the kernel
to use the "year1-year3" format, as opposed to "year1, year2, year3".
This seems to make lawyers more happy, but also prevents the
lines from getting excessively long as the years start to add up.

Suggested by:	imp
2004-02-22 00:33:12 +00:00
Robert Watson
4795b82c13 Coalesce pipe allocations and frees. Previously, the pipe code
would allocate two 'struct pipe's from the pipe zone, and malloc a
mutex.

- Create a new "struct pipepair" object holding the two 'struct
  pipe' instances, struct mutex, and struct label reference.  Pipe
  structures now have a back-pointer to the pipe pair, and a
  'pipe_present' flag to indicate whether the half has been
  closed.

- Perform mutex init/destroy in zone init/destroy, avoiding
  reallocating the mutex for each pipe.  Perform most pipe structure
  setup in zone constructor.

- VM memory mappings for pageable buffers are still done outside of
  the UMA zone.

- Change MAC API to speak 'struct pipepair' instead of 'struct pipe',
  update many policies.  MAC labels are also handled outside of the
  UMA zone for now.  Label-only policy modules don't have to be
  recompiled, but if a module is recompiled, its pipe entry points
  will need to be updated.  If a module actually reached into the
  pipe structures (unlikely), that would also need to be modified.

These changes substantially simplify failure handling in the pipe
code as there are many fewer possible failure modes.

On half-close, pipes no longer free the 'struct pipe' for the closed
half until a full-close takes place.  However, VM mapped buffers
are still released on half-close.

Some code refactoring is now possible to clean up some of the back
references, etc; this patch attempts not to change the structure
of most of the pipe implementation, only allocation/free code
paths, so as to avoid introducing bugs (hopefully).

This cuts about 8%-9% off the cost of sequential pipe allocation
and free in system call tests on UP and SMP in my micro-benchmarks.
May or may not make a difference in macro-benchmarks, but doing
less work is good.

Reviewed by:	juli, tjr
Testing help:	dwhite, fenestro, scottl, et al
2004-02-01 05:56:51 +00:00