While searching for an element using a function it may be
desirable to know the element key for future operation.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
The method will now return 0 on success and -1 on error, rather than number of
items which it iterated over before it returned back to the caller. Since the
only place where we actually check the number of elements iterated is in
virhashtest, return value of 0 and -1 can be a pretty accurate hint that it
iterated over all the items. However, if we really want to know the number of
items iterated over (like virhashtest does), a counter has to be provided
through opaque data to each iterator call. This patch adjusts return value of
virHashForEach, refactors the body, so it returns as soon as one of the
iterators fail and adjusts virhashtest to reflect these changes.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Our existing virHashForEach method iterates through all items disregarding the
fact, that some of the iterators might have actually failed. Errors are usually
dispatched through an error element in opaque data which then causes the
original caller of virHashForEach to return -1. In that case, virHashForEach
could return as soon as one of the iterators fail. This patch changes the
iterator return type and adjusts all of its instances accordingly, so the
actual refactor of virHashForEach method can be dealt with later.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
This is a self-locking wrapper around virHashTable. Only a limited set
of APIs are implemented now (the ones which are used in the following
patch) as more can be added on demand.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
I almost wrote a hash value free function that just called
VIR_FREE, then realized I couldn't be the first person to
do that. Sure enough, it was worth factoring into a common
helper routine.
* src/util/virhash.h (virHashValueFree): New function.
* src/util/virhash.c (virHashValueFree): Implement it.
* src/util/virobject.h (virObjectFreeHashData): New function.
* src/libvirt_private.syms (virhash.h, virobject.h): Export them.
* src/nwfilter/nwfilter_learnipaddr.c (virNWFilterLearnInit): Use
common function.
* src/qemu/qemu_capabilities.c (virQEMUCapsCacheNew): Likewise.
* src/qemu/qemu_command.c (qemuDomainCCWAddressSetCreate):
Likewise.
* src/qemu/qemu_monitor.c (qemuMonitorGetBlockInfo): Likewise.
* src/qemu/qemu_process.c (qemuProcessWaitForMonitor): Likewise.
* src/util/virclosecallbacks.c (virCloseCallbacksNew): Likewise.
* src/util/virkeyfile.c (virKeyFileParseGroup): Likewise.
* tests/qemumonitorjsontest.c
(testQemuMonitorJSONqemuMonitorJSONGetBlockInfo): Likewise.
Signed-off-by: Eric Blake <eblake@redhat.com>
'const fooPtr' is the same as 'foo * const' (the pointer won't
change, but it's contents can). But in general, if an interface
is trying to be const-correct, it should be using 'const foo *'
(the pointer is to data that can't be changed).
Fix up virhash to provide a const-correct interface: all actions
that don't modify the table take a const table. Note that in
one case (virHashSearch), we actually strip const away - we aren't
modifying the contents of the table, so much as associated data
for ensuring that the code uses the table correctly (if this were
C++, it would be a case for the 'mutable' keyword).
* src/util/virhash.h (virHashKeyComparator, virHashEqual): Use
intended type.
(virHashSize, virHashTableSize, virHashLookup, virHashSearch):
Make const-correct.
* src/util/virhash.c (virHashEqualData, virHashEqual)
(virHashLookup, virHashSize, virHashTableSize, virHashSearch)
(virHashComputeKey): Fix fallout.
* src/conf/nwfilter_params.c
(virNWFilterFormatParameterNameSorter): Likewise.
* src/nwfilter/nwfilter_ebiptables_driver.c
(ebiptablesFilterOrderSort): Likewise.
* tests/virhashtest.c (testHashGetItemsCompKey)
(testHashGetItemsCompValue): Likewise.
Signed-off-by: Eric Blake <eblake@redhat.com>
Recent discussions have illustrated the potential for DOS attacks
with the hash table implementations used by most languages and
libraries.
https://lwn.net/Articles/474912/
libvirt has an internal hash table impl, and uses hash tables for
a variety of purposes. The hash key generation code is pretty
simple and thus not strongly collision resistant.
This patch replaces the current libvirt hash key generator with
the (public domain) Murmurhash3 code. In addition every hash
table now gets a random seed value which is used to perturb the
hashing code. This should make it impossible to mount any
practical attack against libvirt hashing code.
* bootstrap.conf: Import bitrotate module
* src/Makefile.am: Add virhashcode.[ch]
* src/util/util.c: Make virRandom() return a fixed 32 bit
integer value.
* src/util/hash.c, src/util/hash.h, src/util/cgroup.c: Replace
hash code generation with a call to virHashCodeGen()
* src/util/virhashcode.h, src/util/virhashcode.c: Add a new
virHashCodeGen() API using the Murmurhash3 algorithm.
In preparation for the patch to include Murmurhash3, which
introduces a virhashcode.h and virhashcode.c files, rename
the existing hash.h and hash.c to virhash.h and virhash.c
respectively.
