Allow nwfilterStateCleanupLocked to be called on a partially constructed
driver object.
This enables the next patch to simplify and fix error handling in
nwfilterStateInitialize.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
The updateLock is a R/W lock held by anything which needs to read or
modify the rules associated with an NWFilter.
APIs for defining/undefining NW filters rules hold a write lock on
updateLock.
APIs for creating/deleting NW filter bindings hold a read lock on
updateLock, which prevents define/undefine taking place concurrently.
The problems arise when we attempt to creating two NW filter bindings in
parallel.
Thread 1 can acquire the mutex for filter A
Thread 2 can acquire the mutex for filter B
Consider if filters A and B both reference filters C and D, but in
different orders:
Filter A
-> filter C
-> filter D
Filter B
-> filter D
-> filter C
Thread 1 will try to acquire locks in order A, C, D while thread 1 will
try to acquire in order A, D, C. Deadlock can still occur.
Think we can sort the list of filters before acquiring locks on all of
them ? Nope, we allow arbitrary recursion:
Filter A
-> filter C
-> filter E
-> filter F
-> filter H
-> filter K
-> filter D
-> filter G
-> filter I
So we can't tell from looking at 'A' which filters we're going to
need to lock. We can only see the first level of filters references
and we need to lock those before we can see the second level of
filters, etc.
We could probably come up with some cleverness to address this but
it isn't worth the time investment. It is simpler to just keep the
process of creating NW filter bindings totally serialized.
Using two separate locks for this serialization though is pointless.
Every code path which gets a read(updateLock) will go on to hold
updateMutex. It is simpler to just hold write(updateLock) and
get rid of updateMutex. At that point we don't need updateLock
to be a R/W lock, it can be a plain mutex.
Thus this patch gets rid of the current updateLock and updateMutex
and introduces a new top level updateMutex.
This has a secondary benefit of introducing fairness into the
locking. With a POSIX R/W lock, you get writer starvation if
you have lots of readers. IOW, if we call virNWFilterBIndingCreate
and virNWFilterBindingDelete in a tight loop from a couple of
threads, we can prevent virNWFilterDefine from ever acquiring
a write lock.
Getting rid of the R/W lock gives us FIFO lock acquisition
preventing starvation of any API call servicing.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This enables a later patch to simplify locking during initialization
and cleanup of virNWFilterDriverState.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Historically, we declared pointer type to our types:
typedef struct _virXXX virXXX;
typedef virXXX *virXXXPtr;
But usefulness of such declaration is questionable, at best.
Unfortunately, we can't drop every such declaration - we have to
carry some over, because they are part of public API (e.g.
virDomainPtr). But for internal types - we can do drop them and
use what every other C project uses 'virXXX *'.
This change was generated by a very ugly shell script that
generated sed script which was then called over each file in the
repository. For the shell script refer to the cover letter:
https://listman.redhat.com/archives/libvir-list/2021-March/msg00537.html
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
When we allow multiple instances of the driver for the same user
account, using a separate root directory, we need to ensure mutual
exclusion. Use a pidfile to guarantee this.
In privileged libvirtd this ends up locking
/var/run/libvirt/nwfilter/driver.pid
In unprivileged libvirtd this ends up locking
/run/user/$UID/libvirt/nwfilter/run/driver.pid
NB, the latter can vary depending on $XDG_RUNTIME_DIR
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Require that all headers are guarded by a symbol named
LIBVIRT_$FILENAME
where $FILENAME is the uppercased filename, with all characters
outside a-z changed into '_'.
Note we do not use a leading __ because that is technically a
namespace reserved for the toolchain.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This introduces a syntax-check script that validates header files use a
common layout:
/*
...copyright header...
*/
<one blank line>
#ifndef SYMBOL
# define SYMBOL
....content....
#endif /* SYMBOL */
For any file ending priv.h, before the #ifndef, we will require a
guard to prevent bogus imports:
#ifndef SYMBOL_ALLOW
# error ....
#endif /* SYMBOL_ALLOW */
<one blank line>
The many mistakes this script identifies are then fixed.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Currently the nwfilter driver does not keep any record of what filter
bindings it has active. This means that when it needs to recreate
filters, it has to rely on triggering callbacks provided by the virt
drivers. This introduces a hash table recording the virNWFilterBinding
objects so the driver has a record of all active filters.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
There is a bunch of left over code in the nwfilter driver related to
monitoring firewalld over dbus, that is no longer used since the
conversion to use virFirewall APIs.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Rename the variable, recent review requested just use of @filter,
so be consistent throughout.
NB: Also change the virNWFilterPtr to be @nwfilter to not conflict
with the renamed variable.
Move from virnwfilterobj.h to virnwfilterobj.c.
Create the virNWFilterObjListNew() API in order to allocate.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Move the structure to virnwfilterobj.c and create necessary accessor API's
for the various fields.
Also make virNWFilterObjFree static since there's no external callers.
Signed-off-by: John Ferlan <jferlan@redhat.com>
When processing a virNWFilterPtr use 'nwfilter' as a variable name.
When processing a virNWFilterObjPtr use 'obj' as a variable name.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Mostly code motion to move nwfilterConnectListNWFilters into nwfilterobj.c
and rename to virNWFilterObjGetNames.
Also includes a couple of variable name adjustments to keep code consistent
with other drivers.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Mostly code motion from nwfilter_driver to virnwfilterobj with one caveat
to add the virNWFilterObjListFilter typedef and pass it as an 'aclfilter'
argument to allow for future possible test driver adjustments to count
the number of filters (similar to how node device has done this).
Signed-off-by: John Ferlan <jferlan@redhat.com>
In an effort to be consistent with the source module, alter the function
prototypes to follow the similar style of source with the "type" on one
line followed by the function name and arguments on subsequent lines with
with argument getting it's own line.
Move all the NWFilterObj API's into their own module virnwfilterobj
from the nwfilter_conf
Purely code motion at this point, plus adjustments to cleanly build.
