GLibC has a really complicated way of dealing with the 'stat' function
historically, which means our mocks in turn have to look at four
different possible functions to replace, stat, stat64, __xstat,
__xstat64.
In Fedora 33 and earlier:
- libvirt.so links to __xstat64
- libc.so library exports stat, stat64, __xstat, __xstat64
- sys/stat.h header exposes stat and __xstat
In Fedora 34 rawhide:
- libvirt.so links to stat64
- libc.so library exports stat, stat64, __xstat, __xstat64
- sys/stat.h header exposes stat
Historically we only looked at the exported symbols from libc.so to
decide which to mock.
In F34 though we must not consider __xstat / __xstat64 though because
they only existance for binary compatibility. Newly built binaries
won't reference them.
Thus we must introduce a header file check into our logic for deciding
which symbol to mock. We must ignore the __xstat / __xstat64 symbols
if they don't appear in the sys/stat.h header, even if they appear
in libc.so
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Commit d6b17edd51 ("tests: Lookup extended stat/lstat in mocks")
adds support for mocking of stat() and lstat() on macOS.
The change was broken because virmockstathelpers.c only follows glibc
logic and MOCK_STAT and MOCK_LSTAT are not getting defined on macOS.
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
There is a typo that prevents initialization of real_lstat.
Fixes: d6b17edd51 ("tests: Lookup extended stat/lstat in mocks")
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Currently, we are mixing: #if HAVE_BLAH with #if WITH_BLAH.
Things got way better with Pavel's work on meson, but apparently,
mixing these two lead to confusing and easy to miss bugs (see
31fb929eca for instance). While we were forced to use HAVE_
prefix with autotools, we are free to chose our own prefix with
meson and since WITH_ prefix appears to be more popular let's use
it everywhere.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Meson always defines _FILE_OFFSET_BITS=64 which effectively makes
mocking of non 64-bit stat functions dead code.
On linux it was not an issue because we use the 64-bit versions but
on FreeBSD there are not 64-bit versions, there is only stat & lstat.
We cannot simply drop the check as that would resolve to compilation
error on 64-bit linux:
{standard input}: Assembler messages:
{standard input}:11468: Error: symbol `__xstat64' is already defined
{standard input}:11679: Error: symbol `__xstat64.cold' is already defined
{standard input}:12034: Error: symbol `__lxstat64' is already defined
{standard input}:12245: Error: symbol `__lxstat64.cold' is already defined
So we have to replace the _FILE_OFFSET_BITS with a check if the
corresponding 64-bit version of the stat function exists.
Replicate the meson behavior by always defining _FILE_OFFSET_BITS
instead of using AC_SYS_LARGEFILE otherwise this change would break
our tests.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Neal Gompa <ngompa13@gmail.com>
Since commit 44e7f02915
util: rewrite auto cleanup macros to use glib's equivalent
VIR_AUTOFREE is just an alias for g_autofree. Use the GLib macros
directly instead of our custom aliases.
Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
gnulib headers change stat, lstat and open to replacement functions,
even for function definitions. This effectively disables standard
library overrides in virfilewrapper and virmockstathelpers since they
are never reached.
Rename the functions and provide a declartion that uses correct
assembler name for the mocks.
This fixes firmware lookup in domaincapstest on macOS.
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
macOS syscall interface (/usr/lib/system/libsystem_kernel.dylib) has
three kinds of stat but only one of them can be used to fill
"struct stat": stat$INODE64.
virmockstathelpers looks up regular stat instead of stat$INODE64. That
causes a failure in qemufirmwaretest because "struct stat" is laid out
differently from the values returned by stat.
Introduce VIR_MOCK_REAL_INIT_ALIASED that can be used to lookup
stat$INODE64 and lstat$INODE64 and use it to setup real functions on
macOS.
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
Quite a few of the tests have a need to mock the stat() / lstat()
functions and they are taking somewhat different & inconsistent
approaches none of which are actually fully correct. This is shown
by fact that 'make check' fails on 32-bit hosts. Investigation
revealed that the code was calling into the native C library impl,
not getting intercepted by our mocks.
The POSIX stat() function might resolve to any number of different
symbols in the C library.
The may be an additional stat64() function exposed by the headers
too.
On 64-bit hosts the stat & stat64 functions are identical, always
refering to the 64-bit ABI.
On 32-bit hosts they refer to the 32-bit & 64-bit ABIs respectively.
Libvirt uses _FILE_OFFSET_BITS=64 on 32-bit hosts, which causes the
C library to transparently rewrite stat() calls to be stat64() calls.
Libvirt will never see the 32-bit ABI from the traditional stat()
call. We cannot assume this rewriting is done using a macro. It might
be, but on GLibC it is done with a magic __asm__ statement to apply
the rewrite at link time instead of at preprocessing.
In GLibC there may be two additional functions exposed by the headers,
__xstat() and __xstat64(). When these exist, stat() and stat64() are
transparently rewritten to call __xstat() and __xstat64() respectively.
The former symbols will not actally exist in the library at all, only
the header. The leading "__" indicates the symbols are a private impl
detail of the C library that applications should not care about.
Unfortunately, because we are trying to mock replace the C library,
we need to know about this internal impl detail.
With all this in mind the list of functions we have to mock will depend
on several factors
- If _FILE_OFFSET_BITS is set, then we are on a 32-bit host, and we
only need to mock stat64 and __xstat64. The other stat / __xstat
functions exist, but we'll never call them so they can be ignored
for mocking.
- If _FILE_OFFSET_BITS is not set, then we are on a 64-bit host and
we should mock stat, stat64, __xstat & __xstat64. Either may be
called by app code.
- If __xstat & __xstat64 exist, then stat & stat64 will not exist
as symbols in the library, so the latter should not be mocked.
The same all applies to lstat()
These rules are complex enough that we don't want to duplicate them
across every mock file, so this centralizes all the logic in a helper
file virmockstathelper.c that should be #included when needed. The
code merely need to provide a filename rewriting callback called
virMockStatRedirect(). Optionally VIR_MOCK_STAT_HOOK can be defined
as a macro if further processing is needed inline.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
