file object. Also explain some possible directions to re-implement it --
I'm not sure it should be, given the minimal application use. (Other
than having the debugger automatically access the symbols for a process,
the main use I'd found was with some minor accounting ability, but _that_
depends on it being in the filesystem space; an ioctl access method would
be useless in that case.)
This is a code-less change; only a comment has been added.
continue doing it despite objections by me (the principal author).
Note that this doesn't fix the real problem -- the real problem is generally
bad setup by ignorant users, and education is the right way to fix it.
So while this doesn't actually solve the prolem mentioned in the complaint
(since it's still possible to do it via other methods, although they mostly
involve a bit more complicity), and there are better methods to do this,
nobody was willing or able to provide me with a real world example that
couldn't be worked around using the existing permissions and group
mechanism. And therefore, security by removing features is the method of
the day.
I only had three applications that used it, in any event. One of them would
have made debugging easier, but I still haven't finished it, and won't
now, so it doesn't really matter.
Merge the contents (less some trivial bordering the silly comments)
of <vm/vm_prot.h> and <vm/vm_inherit.h> into <vm/vm.h>. This puts
the #defines for the vm_inherit_t and vm_prot_t types next to their
typedefs.
This paves the road for the commit to follow shortly: change
useracc() to use VM_PROT_{READ|WRITE} rather than B_{READ|WRITE}
as argument.
to remove 'b'lock devices. The agreement is, essentially, that
block devices will be collapsed into character devices as a first
step (though I don't particularly agree), and raw device names 'rxxx'
will become simply 'xxx' in devfs in the second step (i.e. no 'rxxx'
names will exist). The renaming will not effect the original /dev
and the expectation is that devfs will eventually (but not immediately)
become the standard way to access devices in the system.
If it is determined that a reimplementation of block device access
characteristics is beneficial, a number of alternatives will
be possible that do not involve resurrecting the 'b'lock device class.
For example, an ioctl() that might be made on an open character device
descriptor or a generic buffered overlay device.
This commit removes the blockdev disablement sysctl which does not
apply to the solution that was reached.
This means that access to block devices nodes will act the
same as char device nodes for disk-like devices.
If you encounter problems after this, where programs accessing
disks directly fail to operate, please use the following command
to revert to previous behaviour:
sysctl -w vfs.bdev_buffered=1
And verify that this was indeed the cause of your trouble.
See the mail-archives of the arch@FreeBSD.org list for background.
two new functions spec_buf{read|write}.
Add sysctl vfs.bdev_buffered which defaults to 1 == true. This
sysctl can be used to experimentally turn buffered behaviour for
bdevs off. I should not be changed while any blockdevices are
open. Remove the misplaced sysctl vfs.enable_userblk_io.
No other changes in behaviour.
-----------------------------
The core of the signalling code has been rewritten to operate
on the new sigset_t. No methodological changes have been made.
Most references to a sigset_t object are through macros (see
signalvar.h) to create a level of abstraction and to provide
a basis for further improvements.
The NSIG constant has not been changed to reflect the maximum
number of signals possible. The reason is that it breaks
programs (especially shells) which assume that all signals
have a non-null name in sys_signame. See src/bin/sh/trap.c
for an example. Instead _SIG_MAXSIG has been introduced to
hold the maximum signal possible with the new sigset_t.
struct sigprop has been moved from signalvar.h to kern_sig.c
because a) it is only used there, and b) access must be done
though function sigprop(). The latter because the table doesn't
holds properties for all signals, but only for the first NSIG
signals.
signal.h has been reorganized to make reading easier and to
add the new and/or modified structures. The "old" structures
are moved to signalvar.h to prevent namespace polution.
Especially the coda filesystem suffers from the change, because
it contained lines like (p->p_sigmask == SIGIO), which is easy
to do for integral types, but not for compound types.
NOTE: kdump (and port linux_kdump) must be recompiled.
Thanks to Garrett Wollman and Daniel Eischen for pressing the
importance of changing sigreturn as well.
a lower layer to an upper layer. I'm not sure how necessary this is
for reading.
Fix bug in union_lookup() (note: there are probably still several bugs
in union_lookup()). This one set lerror as a side effect without
setting lowervp, causing copyup code further on down to crash on a null
lowervp pointer. Changed the side effect to use a temporary variable
instead.
fixed (many due to changing semantics in other parts of the kernel and not
the original author's fault), including one critical one: unionfs could
cause UFS corruption in the fronting store due to calling VOP_OPEN for
writing without turning on vmio for the UFS vnode.
Most of the bugs were related to semantics changes in VOP calls, lock
ordering problems (causing deadlocks), improper handling of a read-only
backing store (such as an NFS mount), improper referencing and locking
of vnodes, not using real struct locks for vnode locking, not using
recursive locks when accessing the fronting store, and things like that.
New functionality has been added: unionfs now has mmap() support, but
only partially tested, and rename has been enhanced considerably.
There are still some things that unionfs cannot do. You cannot
rename a directory without confusing unionfs, and there are issues
with softlinks, hardlinks, and special files. unionfs mostly doesn't
understand them (and never did).
There are probably still panic situations, but hopefully no where near
as many as before this commit.
The unionfs in this commit has been tested overlayed on /usr/src
(backing /usr/src being a read-only NFS mount, fronting /usr/src being
a local filesystem). kernel builds have been tested, buildworld is
undergoing testing. More testing is necessary.
have been there in the first place. A GENERIC kernel shrinks almost 1k.
Add a slightly different safetybelt under nostop for tty drivers.
Add some missing FreeBSD tags
fields in struct cdevsw:
d_stop moved to struct tty.
d_reset already unused.
d_devtotty linkage now provided by dev_t->si_tty.
These fields will be removed from struct cdevsw together with
d_params and d_maxio Real Soon Now.
The changes in this patch consist of:
initialize dev->si_tty in *_open()
initialize tty->t_stop
remove devtotty functions
rename ttpoll to ttypoll
a few adjustments to these changes in the generic code
a bump of __FreeBSD_version
add a couple of FreeBSD tags
d_maxio is replaced by the dev->si_iosize_max field which the driver
should be set in all calls to cdevsw->d_open if it has a better
idea than the system wide default.
The field is a generic dev_t field (ie: not disk specific) so that
tapes and other devices can use physio as well.
heuristic to detect sequential operation.
VM-related forced clustering code removed from ufs in preparation for a
commit to vm/vm_fault.c that does it more generally.
Reviewed by: David Greenman <dg@root.com>, Alan Cox <alc@cs.rice.edu>
transfer size calculation was incorrect resulting in the last read being
potentially larger then the actual extent of the device.
EOF and write handling has not yet been fixed.
Reviewed by: Tor.Egge@fast.no
Rename dev->si_bsize_max to si_iosize_max and set it in spec_open
if the device didn't.
Set vp->v_maxio from dev->si_bsize_max in spec_open rather than
in ufs_bmap.c
to buffered block devices are allowed. The default is to be backwards
compatible, i.e. reads and writes are allowed.
The idea is for a larger crowd to start running with this disabled and
see what problems, if any, crop up, and then to change the default to
off and see if any problems crop up in the next 6 months prior to
potentially removing support entirely. There are still a few people,
Julian and myself included, who believe the buffered block device
access from usermode to be useful.
Remove use of vnode->v_lastr from buffered block device I/O in
preparation for removal of vnode->v_lastr field, replacing it with
the already existing seqcount metric to detect sequential operation.
Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
reasonable defaults.
This avoids confusing and ugly casting to eopnotsupp or making dummy functions.
Bogus casting of filesystem sysctls to eopnotsupp() have been removed.
This should make *_vfsops.c more readable and reduce bloat.
Reviewed by: msmith, eivind
Approved by: phk
Tested by: Jeroen Ruigrok/Asmodai <asmodai@wxs.nl>
the other XXXFS_DIAGNOSTIC options (not very) and mostly controlled
tracing of normal operation. Use `#ifdef DEBUG' for non-diagnostics
and `#ifdef DIAGNOSTIC' for diagnostics.
a quick think and discussion among various people some form of some of
these changes will probably be recommitted.
The reversion requested was requested by dg while discussions proceed.
PHK has indicated that he can live with this, and it has been agreed
that some form of some of these changes may return shortly after further
discussion.
