I'm not sure why a credential was added to these in the first place, it is
not used anywhere and it doesn't make much sense:
The credentials for syncing a file (ability to write to the
file) should be checked at the system call level.
Credentials for syncing one or more filesystems ("none")
should be checked at the system call level as well.
If the filesystem implementation needs a particular credential
to carry out the syncing it would logically have to the
cached mount credential, or a credential cached along with
any delayed write data.
Discussed with: rwatson
Use this in all the places where sleeping with the lock held is not
an issue.
The distinction will become significant once we finalize the exact
lock-type to use for this kind of case.
somewhat clearer, but more importantly allows for a consistent naming
scheme for suser_cred flags.
The old name is still defined, but will be removed in a few days (unless I
hear any complaints...)
Discussed with: rwatson, scottl
Requested by: jhb
This is to allow filesystems to decide based on the passed thread
which vnode to return.
Several filesystems used curthread, they now use the passed thread.
older API to list attributes on a file (zero-length attribute name)
to function. extattr_list_*() are now the only available APIs to
use when listing attributes.
- don't say what a small subset of the options includes are for.
- don't mark up functions which use all their args with /* ARGSUSED */.
The markup should have been removed when the unused retval parameter
was removed.
- don't comment on what routine suser() checks do. Removed nearby
excessive vertical whitespace.
Use kern_open() to implement creat() rather than taking the long route
through open(). Mark creat as MPSAFE.
While I'm at it, mark nosys() (syscall 0) as MPSAFE, for all the
difference it will make.
- security.bsd.hardlink_check_uid, when set, means, that unprivileged
users are not permitted to create hard links to files not
owned by them,
- security.bsd.hardlink_check_gid, when set, means, that unprivileged
users are not permitted to create hard links to files owned
by group they don't belong to.
OK'ed by: rwatson
data for the file system on which the jail's root vnode is located.
Previous behavior (show data for all mountpoints) can be restored
by setting security.jail.getfsstatroot_only to 0. Note: this also
has the effect of hiding other mounts inside a jail, such as /dev,
/tmp, and /proc, but errs on the side of leaking less information.
in OpenBSD by Niels Provos. The patch introduces a bitmap of allocated
file descriptors which is used to locate available descriptors when a new
one is needed. It also moves the task of growing the file descriptor table
out of fdalloc(), reducing complexity in both fdalloc() and do_dup().
Debts of gratitude are owed to tjr@ (who provided the original patch on
which this work is based), grog@ (for the gdb(4) man page) and rwatson@
(for assistance with pxeboot(8)).
accurate reporting of multi-terabyte filesystem sizes.
You should build and boot a new kernel BEFORE doing a `make world'
as the new kernel will know about binaries using the old statfs
structure, but an old kernel will not know about the new system
calls that support the new statfs structure. Running an old kernel
after a `make world' will cause programs such as `df' that do a
statfs system call to fail with a bad system call.
Reviewed by: Bruce Evans <bde@zeta.org.au>
Reviewed by: Tim Robbins <tjr@freebsd.org>
Reviewed by: Julian Elischer <julian@elischer.org>
Reviewed by: the hoards of <arch@freebsd.org>
Sponsored by: DARPA & NAI Labs.
table, acquiring the necessary locks as it works. It usually returns
two references to the new descriptor: one in the descriptor table
and one via a pointer argument.
As falloc releases the FILEDESC lock before returning, there is a
potential for a process to close the reference in the file descriptor
table before falloc's caller gets to use the file. I don't think this
can happen in practice at the moment, because Giant indirectly protects
closes.
To stop the file being completly closed in this situation, this change
makes falloc set the refcount to two when both references are returned.
This makes life easier for several of falloc's callers, because the
first thing they previously did was grab an extra reference on the
file.
Reviewed by: iedowse
Idea run past: jhb
explicit access control checks to delete and list extended attributes
on a vnode, rather than implicitly combining with the setextattr and
getextattr checks. This reflects EA API changes in the kernel made
recently, including the move to explicit VOP's for both of these
operations.
Obtained from: TrustedBSD PRoject
Sponsored by: DARPA, Network Associates Laboratories
use vrele() instead of vput() on the parent directory vnode returned
by namei() in the case where it is equal to the target vnode. This
handles namei()'s somewhat strange (but documented) behaviour of
not locking either vnode when the two vnodes are equal and LOCKPARENT
but not LOCKLEAF is specified.
Note that since a vnode double-unlock is not currently fatal, these
coding errors were effectively harmless.
Spotted by: Juergen Hannken-Illjes <hannken@eis.cs.tu-bs.de>
Reviewed by: mckusick
kernel ACL interfaces and system call names.
Break out UFS2 and FFS extattr delete and list vnode operations from
setextattr and getextattr to deleteextattr and listextattr, which
cleans up the implementations, and makes the results more readable,
and makes the APIs more clear.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
contain the filedescriptor number on opens from userland.
The index is used rather than a "struct file *" since it conveys a bit
more information, which may be useful to in particular fdescfs and /dev/fd/*
For now pass -1 all over the place.
attributes from objects over vop_setextattr() with a NULL uio; if
the file system doesn't support the vop_rmextattr() method, fall
back to the vop_setextattr() method.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
Several of the subtypes have an associated vnode which is used for
stuff like the f*() functions.
By giving the vnode a speparate field, a number of checks for the specific
subtype can be replaced simply with a check for f_vnode != NULL, and
we can later free f_data up to subtype specific use.
At this point in time, f_data still points to the vnode, so any code I
might have overlooked will still work.
mutexes are supposed to only be used as leaf mutexes, and what appear
to be separate pool mutexes could be aliased together, it is bad idea
for a thread to attempt to hold two pool mutexes at the same time.
Slightly rearrange the code in kern_open() so that FILE_UNLOCK() is
called before calling VOP_GETVOBJECT(), which will grab the v_vnlock
mutex.
"", temporarily map it to a call to extattr_list_vp() to provide
compatibility for older applications using the "" API to retrieve
EA lists.
Use VOP_LISTEXTATTR() to support extattr_list_vp() rather than
VOP_GETEXTATTR(..., "", ...).
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Asssociates Laboratories
extattr_list_link() system calls, which return a least of extended
attributes defined for a vnode referenced by a file descriptor
or path name. Currently, we just invoke VOP_GETEXTATTR() since
it will convert a request for an empty name into a query for a
name list, which was the old (more hackish) API. At some point
in the near future, we'll push the distinction between get and
list down to the vnode operation layer, but this provides access
to the new API for applications in the short term.
Pointed out by: Dominic Giampaolo <dbg@apple.com>
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
- Add a parameter to vm_pageout_flush() that tells vm_pageout_flush()
whether its caller has locked the vm_object. (This is a temporary
measure to bootstrap vm_object locking.)
by allprison_mtx), a unique prison/jail identifier field, two path
fields (pr_path for reporting and pr_root vnode instance) to store
the chroot() point of each jail.
o Add jail_attach(2) to allow a process to bind to an existing jail.
o Add change_root() to perform the chroot operation on a specified
vnode.
o Generalize change_dir() to accept a vnode, and move namei() calls
to callers of change_dir().
o Add a new sysctl (security.jail.list) which is a group of
struct xprison instances that represent a snapshot of active jails.
Reviewed by: rwatson, tjr
before the MAC check so that we pass the flags field into the MAC
check properly initialized. This didn't affect any current MAC
modules since they didn't care what the flags argument was (as
they were primarily interested in the fact that it was a meta-data
write, not the contents of the write), but would be relevant to
future modules relying on that field.
Submitted by: Mike Halderman <mrh@spawar.navy.mil>
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
than having change_dir() release the vnode lock on success, hold the
lock so that we can use it later when invoking MAC checks and
VOP_ACCESS() in the chroot() code. Update the comment to reflect
this calling convention. Update callers to unlock the vnode
lock. Correct a typo regarding vnode naming in the MAC case that
crept in via the previous patch applied.
cases: we might multiply vrele() a vnode when certain classes of
failures occur. This appears to stem from earlier Giant/file
descriptor lock pushdown and restructuring.
Submitted by: maxim
pointer types, and remove a huge number of casts from code using it.
Change struct xfile xf_data to xun_data (ABI is still compatible).
If we need to add a #define for f_data and xf_data we can, but I don't
think it will be necessary. There are no operational changes in this
commit.
The leak in lseek was introduced in vfs_syscalls.c revision 1.218.
The leak in do_dup was introduced in kern_descrip.c revision 1.158.
Submitted by: iedowse
missed. This bug has been present since the vn_start_write() and
vn_finished_write() calls were first added in revision 1.159. When
the case is triggered, any attempts to create snapshots on the
filesystem will deadlock and also prevent further write activity
on that filesystem.
to conform to 1003.1-2001. Make it possible for applications to actually
tell whether or not asynchronous I/O is supported.
Since FreeBSD's aio implementation works on all descriptor types, don't
call down into file or vnode ops when [f]pathconf() is asked about
_PC_ASYNC_IO; this avoids the need for every file and vnode op to know about
it.
creation, deletion, and rename. There are one or two other stray
cases I'll catch in follow-up commits (such as unix domain socket
creation); this permits MAC policy modules to limit the ability to
perform these operations based on existing UNIX credential / vnode
attributes, extended attributes, and security labels. In the rename
case using MAC, we now have to lock the from directory and file
vnodes for the MAC check, but this is done only in the MAC case,
and the locks are immediately released so that the remainder of the
rename implementation remains the same. Because the create check
takes a vattr to know object type information, we now initialize
additional fields in the VATTR passed to VOP_SYMLINK() in the MAC
case.
Approved by: re
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
revision 1.218. This bug caused a "struct file" reference to be
leaked if VOP_ADVLOCK(), vn_start_write(), or mac_check_vnode_write()
failed during the open operation.
PR: kern/43739
Reported by: Arne Woerner <woerner@mediabase-gmbh.de>
point that instruments the creation of hard links. Policy implementations
to follow.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
wasn't doing. Rather than just lock and unlock the vnode around the call
to VOP_FSYNC(), implement rwatson's suggestion to lock the file vnode
in kern_link() before calling VOP_LINK(), since the other filesystems
also locked the file vnode right away in their link methods. Remove the
locking and and unlocking from the leaf filesystem link methods.
Reviewed by: rwatson, bde (except for the unionfs_link() changes)
Changed rename(2) to follow the letter of the POSIX spec. POSIX
requires rename() to have no effect if its args "resolve to the same
existing file". I think "file" can only reasonably be read as referring
to the inode, although the rationale and "resolve" seem to say that
sameness is at the level of (resolved) directory entries.
ext2fs_vnops.c, ufs_vnops.c:
Replaced code that gave the historical BSD behaviour of removing one
link name by checks that this code is now unreachable. This fixes
some races. All vnodes needed to be unlocked for the removal, and
locking at another level using something like IN_RENAME was not even
attempted, so it was possible for rename(x, y) to return with both x
and y removed even without any unlink(2) syscalls (one process can
remove x using rename(x, y) and another process can remove y using
rename(y, x)).
Prodded by: alfred
MFC after: 8 weeks
PR: 42617
a kernel-internal kern_*() version and a wrapper that is called via
the syscall vector table. For paths and structure pointers, the
internal version either takes a uio_seg parameter or requires the
caller to copyin() the data to kernel memory as appropiate. This
will permit emulation layers to use these syscalls without having
to copy out translated arguments to the stack gap.
Discussed on: -arch
Review/suggestions: bde, jhb, peter, marcel
for mac_check_vnode_{poll,read,stat,write}(). Pass in fp->f_cred
when calling these checks with a struct file available. Otherwise,
pass NOCRED. All currently MAC policies use active_cred, but
could now offer the cached credential semantic used for the base
system security model.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
mac_check_vnode_poll(), mac_check_vnode_read(), mac_check_vnode_write().
This improves the consistency with other existing vnode checks, and
allows policies to avoid implementing switch statements to determine
what operations they do and do not want to authorize.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
fo_read() and fo_write(): explicitly use the cred argument to fo_poll()
as "active_cred" using the passed file descriptor's f_cred reference
to provide access to the file credential. Add an active_cred
argument to fo_stat() so that implementers have access to the active
credential as well as the file credential. Generally modify callers
of fo_stat() to pass in td->td_ucred rather than fp->f_cred, which
was redundantly provided via the fp argument. This set of modifications
also permits threads to perform these operations on behalf of another
thread without modifying their credential.
Trickle this change down into fo_stat/poll() implementations:
- badfo_poll(), badfo_stat(): modify/add arguments.
- kqueue_poll(), kqueue_stat(): modify arguments.
- pipe_poll(), pipe_stat(): modify/add arguments, pass active_cred to
MAC checks rather than td->td_ucred.
- soo_poll(), soo_stat(): modify/add arguments, pass fp->f_cred rather
than cred to pru_sopoll() to maintain current semantics.
- sopoll(): moidfy arguments.
- vn_poll(), vn_statfile(): modify/add arguments, pass new arguments
to vn_stat(). Pass active_cred to MAC and fp->f_cred to VOP_POLL()
to maintian current semantics.
- vn_close(): rename cred to file_cred to reflect reality while I'm here.
- vn_stat(): Add active_cred and file_cred arguments to vn_stat()
and consumers so that this distinction is maintained at the VFS
as well as 'struct file' layer. Pass active_cred instead of
td->td_ucred to MAC and to VOP_GETATTR() to maintain current semantics.
- fifofs: modify the creation of a "filetemp" so that the file
credential is properly initialized and can be used in the socket
code if desired. Pass ap->a_td->td_ucred as the active
credential to soo_poll(). If we teach the vnop interface about
the distinction between file and active credentials, we would use
the active credential here.
Note that current inconsistent passing of active_cred vs. file_cred to
VOP's is maintained. It's not clear why GETATTR would be authorized
using active_cred while POLL would be authorized using file_cred at
the file system level.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
- v_vflag is protected by the vnode lock and is used when synchronization
with VOP calls is needed.
- v_iflag is protected by interlock and is used for dealing with vnode
management issues. These flags include X/O LOCK, FREE, DOOMED, etc.
- All accesses to v_iflag and v_vflag have either been locked or marked with
mp_fixme's.
- Many ASSERT_VOP_LOCKED calls have been added where the locking was not
clear.
- Many functions in vfs_subr.c were restructured to provide for stronger
locking.
Idea stolen from: BSD/OS
kernel access control.
Invoke appropriate MAC framework entry points to authorize readdir()
operations in the native ABI.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
kernel access control.
Instrument chdir() and chroot()-related system calls to invoke
appropriate MAC entry points to authorize the two operations.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
kernel access control.
Implement MAC framework access control entry points relating to
operations on mountpoints. Currently, this consists only of
access control on mountpoint listing using the various statfs()
variations. In the future, it might also be desirable to
implement checks on mount() and unmount().
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
open() of fhopen(). Currently this has no actual affect due to the
treatment of VAPPEND in vaccess() and vaccess_acl() as a subset of
VWRITE, but when MAC comes in, MAC will distinguish the two. Note:
if any file systems are cutting their own permission models, they
may wish to now take this into account.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
support creation times such as UFS2) to the value of the
modification time if the value of the modification time is older
than the current creation time. See utimes(2) for further details.
Sponsored by: DARPA & NAI Labs.
filedesc is already locked rather than having chroot() unlock the
filedesc so chroot_refuse_vdir_fds() can immediately relock it.
- Reorder chroot() a bitso that we do the namei lookup before checking
the process's struct filedesc. This closes at least one potential race
and allows us to only acquire the filedsec lock once in chroot().
- Push down Giant slightly into chroot().
The file vfs_conf.c which was dealing with root mounting has
been repo-copied into vfs_mount.c to preserve history.
This makes nmount related development easier, and help reducing
the size of vfs_syscalls.c, which is still an enormous file.
Reviewed by: rwatson
Repo-copy by: peter
direct calls for the two places where the kernel calls into soft
updates code. Set up the hooks in softdep_initialize() and NULL
them out in softdep_uninitialize(). This change allows soft updates
to function correctly when ufs is loaded as a module.
Reviewed by: mckusick
vnode in the case that the target exists and is the same vnode as
the parent (i.e. "mkdir ."). The namei() call does not leave the
vnode locked in this case even though you might expect it to.
This bug was mostly harmless in practice because unlocking an already
unlocked vnode currently does not trigger any panics or warnings.
Reviewed by: jeff
64-bit architectures that was introduced in the UFS2 code
merge two days ago. The stat structure change that caused
the problem was the addition of the file create time.
Submitted by: Bruce Evans <bde@zeta.org.au>
Sponsored by: DARPA & NAI Labs.
uio now that we don't use uiomove() anymore.
o Enforce stricter checks on the length of the iov's in
nmount(2) since we now malloc() them individually and
corrupted iov's could make the kernel crash in malloc()
with "kmem_map too small".
Reviewed by: phk
filesystem expands the inode to 256 bytes to make space for 64-bit
block pointers. It also adds a file-creation time field, an ability
to use jumbo blocks per inode to allow extent like pointer density,
and space for extended attributes (up to twice the filesystem block
size worth of attributes, e.g., on a 16K filesystem, there is space
for 32K of attributes). UFS2 fully supports and runs existing UFS1
filesystems. New filesystems built using newfs can be built in either
UFS1 or UFS2 format using the -O option. In this commit UFS1 is
the default format, so if you want to build UFS2 format filesystems,
you must specify -O 2. This default will be changed to UFS2 when
UFS2 proves itself to be stable. In this commit the boot code for
reading UFS2 filesystems is not compiled (see /sys/boot/common/ufsread.c)
as there is insufficient space in the boot block. Once the size of the
boot block is increased, this code can be defined.
Things to note: the definition of SBSIZE has changed to SBLOCKSIZE.
The header file <ufs/ufs/dinode.h> must be included before
<ufs/ffs/fs.h> so as to get the definitions of ufs2_daddr_t and
ufs_lbn_t.
Still TODO:
Verify that the first level bootstraps work for all the architectures.
Convert the utility ffsinfo to understand UFS2 and test growfs.
Add support for the extended attribute storage. Update soft updates
to ensure integrity of extended attribute storage. Switch the
current extended attribute interfaces to use the extended attribute
storage. Add the extent like functionality (framework is there,
but is currently never used).
Sponsored by: DARPA & NAI Labs.
Reviewed by: Poul-Henning Kamp <phk@freebsd.org>
a linked list. This is to allow the merging of the mount
options in the MNT_UPDATE case, as the current data structure
is unsuitable for this.
There are no functional differences in this commit.
Reviewed by: phk
in various extattr_*() calls to match the rest of the file. Originally,
these bits at the end looked more like style(9). This patch was submitted
by green by way of the TrustedBSD MAC tree, and I fixed a few problems
with it on the way through. Someone with more time on their hands should
convert the entire file to style(9); this commit is for diff reduction
purposes.
Submitted by: green
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
where some client operations might be unexpectedly cancelled during
an unsuccessful non-forced unmount attempt. This causes problems
for amd(8), because it periodically attempts a non-forced unmount
to check if the filesystem is still in use.
Fix this by adding a new mountpoint flag MNTK_UNMOUNTF that is set
only during the operation of a forced unmount. Use this instead of
MNTK_UNMOUNT to trigger the cancellation of hung NFS operations.
Also correct a problem where dounmount() might inadvertently clear
the MNTK_UNMOUNT flag.
Reported by: simokawa
MFC after: 1 week
behavior by default. Also, change the options line to reflect this.
If there are no problems reported this will become the only behavior and the
knob will be removed in a month or so.
Demanded by: obrien
separate strings instead of passing "foo=bar".
o Don't forget to clear the VMOUNT flag on the vnode when vfs_nmount()
fails because the fs doesn't implement VFS_NMOUNT (and in vfs_mount()
when the fs doesn't implement VFS_MOUNT) ; also decrement the vfs
refcount in the !MNT_UPDATE case.
general cleanup of the API. The entire API now consists of two functions
similar to the pre-KSE API. The suser() function takes a thread pointer
as its only argument. The td_ucred member of this thread must be valid
so the only valid thread pointers are curthread and a few kernel threads
such as thread0. The suser_cred() function takes a pointer to a struct
ucred as its first argument and an integer flag as its second argument.
The flag is currently only used for the PRISON_ROOT flag.
Discussed on: smp@
in vfs_mount(), in particular revisions 1.215, 1.227 and 1.240.
- flag2 is a low quality variable name, change it to kern_flag.
- strncpy NUL-terminates f_fstypename and f_mntonname since the strings
have length <= <buffer length> - 1, so the explicit NUL-termination is
bogus.
- M_ZERO'ing space for fstype and fspath is stupid since we never use the
space beyond the end of the string.
- Do various style(9) cleanups in both functions.
Submitted by: bde
Reviewed by: phk
- return error -> return (error);
- move a declaration to the top of the function.
- become bug for bug compatible with if (error) lines.
Submitted by: bde
new vfs_getopt()/vfs_copyopt() API. This is intended to be used
later, when there will be filesystems implementing the VFS_NMOUNT
operation. The mount(2) system call will disappear when all
filesystems will be converted to the new API. Documentation will
be committed in a while.
Reviewed by: phk
kern_linker.c and rev. 1.237 of vfs_syscalls.c since these are not the
source of the recent panics occuring around kldloading file system
support modules.
Requested by: rwatson
made aware in jail environments. Supposedly something is broken, so
this should be backed out until further investigation proves otherwise,
or a proper fix can be provided.
against users within a jail attempting to load kernel modules.
- Add a check of securelevel_gt() to vfs_mount() in order to chop some
low hanging fruit for the repair of securelevel checking of linking and
unlinking files from within jails. There is more to be done here.
Reviewed by: rwatson
The stat() and open() calls have been changed to make use of this new functionality. Using shared locks in
these cases is sufficient and can significantly reduce their latency if IO is pending to these vnodes. Also,
this reduces the number of exclusive locks that are floating around in the system, which helps reduce the
number of deadlocks that occur.
A new kernel option "LOOKUP_SHARED" has been added. It defaults to off so this patch can be turned on for
testing, and should eventually go away once it is proven to be stable. I have personally been running this
patch for over a year now, so it is believed to be fully stable.
Reviewed by: jake, obrien
Approved by: jake
to perform an ownership test in revoke(). This is also required for
MAC hooks so that the vnode lock is held during a call to the MAC
framework. Release the lock before calling VOP_REVOKE().
Discussed with: phk, mckusick
o Modify the system call syntax for extattr_{get,set}_{fd,file}() so
as not to use the scatter gather API (which appeared not to be used
by any consumers, and be less portable), rather, accepts 'data'
and 'nbytes' in the style of other simple read/write interfaces.
This changes the API and ABI.
o Modify system call semantics so that extattr_get_{fd,file}() return
a size_t. When performing a read, the number of bytes read will
be returned, unless the data pointer is NULL, in which case the
number of bytes of data are returned. This changes the API only.
o Modify the VOP_GETEXTATTR() vnode operation to accept a *size_t
argument so as to return the size, if desirable. If set to NULL,
the size will not be returned.
o Update various filesystems (pseodofs, ufs) to DTRT.
These changes should make extended attributes more useful and more
portable. More commits to rebuild the system call files, as well
as update userland utilities to follow.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
- Fix null-pointer dereference introduced when snapshotting
was introduced. This occured because unlike the previous code,
vn_start_write() doesn't always return a non-NULL mp, as
filesystems may not support the VOP_GETWRITEMOUNT() call. For
now, rely on two pointers, so that vn_finished_write() works
properly.
- Fix locking problems on exit, introduced at some past time,
some when snapshots came in, where a vnode might not be
unlocked before being vrele'd in various error situations.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
this is a low-functionality change that changes the kernel to access the main
thread of a process via the linked list of threads rather than
assuming that it is embedded in the process. It IS still embeded there
but remove all teh code that assumes that in preparation for the next commit
which will actually move it out.
Reviewed by: peter@freebsd.org, gallatin@cs.duke.edu, benno rice,
Seigo Tanimura (tanimura) posted the initial delta.
I've polished it quite a bit reducing the need for locking and
adapting it for KSE.
Locks:
1 mutex in each filedesc
protects all the fields.
protects "struct file" initialization, while a struct file
is being changed from &badfileops -> &pipeops or something
the filedesc should be locked.
1 mutex in each struct file
protects the refcount fields.
doesn't protect anything else.
the flags used for garbage collection have been moved to
f_gcflag which was the FILLER short, this doesn't need
locking because the garbage collection is a single threaded
container.
could likely be made to use a pool mutex.
1 sx lock for the global filelist.
struct file * fhold(struct file *fp);
/* increments reference count on a file */
struct file * fhold_locked(struct file *fp);
/* like fhold but expects file to locked */
struct file * ffind_hold(struct thread *, int fd);
/* finds the struct file in thread, adds one reference and
returns it unlocked */
struct file * ffind_lock(struct thread *, int fd);
/* ffind_hold, but returns file locked */
I still have to smp-safe the fget cruft, I'll get to that asap.
can't acquire the mnt_lock without blocking. Normally non-forced
unmount attempts return EBUSY quickly if any vnodes are active, so
this just extends that behaviour to cover the per-mount mnt_lock
too.
