The viratomictest.c was casting from an int to a void* via a
long. This works on Linux or Mingw32, but fails on Mingw64
due to a pointer/integer size mis-match. Replacing 'long'
with 'intptr_t' ensures matching type sizes
All callers used the same initialization seed (well, the new
viratomictest forgot to look at getpid()); so we might as well
make this value automatic. And while it may feel like we are
giving up functionality, I documented how to get it back in the
unlikely case that you actually need to debug with a fixed
pseudo-random sequence. I left that crippled by default, so
that a stray environment variable doesn't cause a lack of
randomness to become a security issue.
* src/util/virrandom.c (virRandomInitialize): Rename...
(virRandomOnceInit): ...and make static, with one-shot call.
Document how to do fixed-seed debugging.
* src/util/virrandom.h (virRandomInitialize): Drop prototype.
* src/libvirt_private.syms (virrandom.h): Don't export it.
* src/libvirt.c (virInitialize): Adjust caller.
* src/lxc/lxc_controller.c (main): Likewise.
* src/security/virt-aa-helper.c (main): Likewise.
* src/util/iohelper.c (main): Likewise.
* tests/seclabeltest.c (main): Likewise.
* tests/testutils.c (virtTestMain): Likewise.
* tests/viratomictest.c (mymain): Likewise.
There are a few issues with the current virAtomic APIs
- They require use of a virAtomicInt struct instead of a plain
int type
- Several of the methods do not implement memory barriers
- The methods do not implement compiler re-ordering barriers
- There is no Win32 native impl
The GLib library has a nice LGPLv2+ licensed impl of atomic
ops that works with GCC, Win32, or pthreads.h that addresses
all these problems. The main downside to their code is that
the pthreads impl uses a single global mutex, instead of
a per-variable mutex. Given that it does have a Win32 impl
though, we don't expect anyone to seriously use the pthread.h
impl, so this downside is not significant.
* .gitignore: Ignore test case
* configure.ac: Check for which atomic ops impl to use
* src/Makefile.am: Add viratomic.c
* src/nwfilter/nwfilter_dhcpsnoop.c: Switch to new atomic
ops APIs and plain int datatype
* src/util/viratomic.h: inline impls of all atomic ops
for GCC, Win32 and pthreads
* src/util/viratomic.c: Global pthreads mutex for atomic
ops
* tests/viratomictest.c: Test validate to validate safety
of atomic ops.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
