On win32, all code is position independent and adding -fPIE
to the compiler flags results in warnings being printed
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
There are a number of places which generate cast alignment
warnings, which are difficult or impossible to address. Use
pragmas to disable the warnings in these few places
conf/nwfilter_conf.c: In function 'virNWFilterRuleDetailsParse':
conf/nwfilter_conf.c:1806:16: warning: cast increases required alignment of target type [-Wcast-align]
item = (nwItemDesc *)((char *)nwf + att[idx].dataIdx);
conf/nwfilter_conf.c: In function 'virNWFilterRuleDefDetailsFormat':
conf/nwfilter_conf.c:3238:16: warning: cast increases required alignment of target type [-Wcast-align]
item = (nwItemDesc *)((char *)def + att[i].dataIdx);
storage/storage_backend_mpath.c: In function 'virStorageBackendCreateVols':
storage/storage_backend_mpath.c:247:17: warning: cast increases required alignment of target type [-Wcast-align]
names = (struct dm_names *)(((char *)names) + next);
nwfilter/nwfilter_dhcpsnoop.c: In function 'virNWFilterSnoopDHCPDecode':
nwfilter/nwfilter_dhcpsnoop.c:994:15: warning: cast increases required alignment of target type [-Wcast-align]
pip = (struct iphdr *) pep->eh_data;
nwfilter/nwfilter_dhcpsnoop.c:1004:11: warning: cast increases required alignment of target type [-Wcast-align]
pup = (struct udphdr *) ((char *) pip + (pip->ihl << 2));
nwfilter/nwfilter_learnipaddr.c: In function 'procDHCPOpts':
nwfilter/nwfilter_learnipaddr.c:327:33: warning: cast increases required alignment of target type [-Wcast-align]
uint32_t *tmp = (uint32_t *)&dhcpopt->value;
nwfilter/nwfilter_learnipaddr.c: In function 'learnIPAddressThread':
nwfilter/nwfilter_learnipaddr.c:501:43: warning: cast increases required alignment of target type [-Wcast-align]
struct iphdr *iphdr = (struct iphdr*)(packet +
nwfilter/nwfilter_learnipaddr.c:538:43: warning: cast increases required alignment of target type [-Wcast-align]
struct iphdr *iphdr = (struct iphdr*)(packet +
nwfilter/nwfilter_learnipaddr.c:544:48: warning: cast increases required alignment of target type [-Wcast-align]
struct udphdr *udphdr= (struct udphdr *)
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
By passing the flags -z relro -z now to the linker, we can force
it to resolve all library symbols at startup, instead of on-demand.
This allows it to then make the global offset table (GOT) read-only,
which makes some security attacks harder.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
PIE (position independent executable) adds security to executables
by composing them entirely of position-independent code (PIC. The
.so libraries already build with -fPIC. This adds -fPIE which is
the equivalent to -fPIC, but for executables. This for allows Exec
Shield to use address space layout randomization to prevent attackers
from knowing where existing executable code is during a security
attack using exploits that rely on knowing the offset of the
executable code in the binary, such as return-to-libc attacks.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virt-dbus.m4 check for DBus was preserving $LIBS before
modifying it. Except it wasn't. It was preserving another
copy of $CFLAGS. The result was that after the check completed,
$LIBS got polluted with $CFLAGS
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Some places missed the conversion from LIBCURL_{CFLAGS,LIBS} to
CURL_{CFLAGS,LIBS}, and a part of curl check was left in
configure.ac instead of m4/virt-curl.m4 by mistake
There are many aspects of the guest XML which result in the
SELinux driver applying file labelling. With the increasing
configuration options it is desirable to test this behaviour.
It is not possible to assume that the test suite has the
ability to set SELinux labels. Most filesystems though will
support extended attributes. Thus for the purpose of testing,
it is possible to extend the existing LD_PRELOAD hack to
override setfilecon() and getfilecon() to simply use the
'user.libvirt.selinux' attribute for the sake of testing.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This converts the libssh2 configure check to use LIBVIRT_CHECK_PKG.
Previously it would check version 1.0 and 1.3, but this simplifies
things to just require version 1.3
Problem introduced in commit cd699ed.
* m4/virt-lib.m4 (LIBVIRT_CHECK_LIB, LIBVIRT_CHECK_PKG): Set up
direct expansions, since autoconf 2.59 lacked m4_expand.
Most checks for libraries take the same format
* --with-libFOO=yes|no|check|/some/path argument
* check for a function NNN in libFOO.so
* check for a header file DDD/HHH.h
* Define a WITH_FOO config.h symbol
* Define a WITH_FOO make conditional
* Substitute FOO_CFLAGS and FOO_LIBS make variables
* Print CFLAGS & LIBS summary at the end
Doing all this correctly is rather difficult, typically
done by copy+paste of a previous usage. Further small
improvements people make are not applied to all previous
usages.
Improve this by creating some helper macros to apply
good practice. First, to perform the actual checks:
LIBVIRT_CHECK_LIB([SELINUX], [selinux],
[getfilecon], [selinux/selinux.h])
This checks for 'getfilecon' in -lselinux, and the
existence of 'selinux/selinux.h' header file. If successful
it sets SELINUX_CFLAGS and SELINUX_LIBS. The WITH_SELINUX
config.h macro and WITH_SELINUX make conditional are also
defined.
In some cases we need to check two variants of the same
library
LIBVIRT_CHECK_LIB_ALT([SASL], [sasl2],
[sasl_client_init], [sasl/sasl.h],
[SASL1], [sasl],
[sasl_client_init], [sasl/sasl.h])
This checks for sasl_client_init in libsasl2, and if that
is not found, checks sasl_client_init in libsasl. If the
first check succeeds WITH_SASL is set, while if the second
check succeeds *both* WITH_SASL and WITH_SASL1 are set.
If the library supports pkg-config, then another variant
is available
LIBVIRT_CHECK_PKG([AVAHI], [avahi-client], [0.6.0])
This checks for avahi-client >= 0.6.0 via pkg-config
and sets WITH_AVAHI if found.
Finally to print a summary of CFLAGS & LIBs found (if any):
LIBVIRT_RESULT_LIB([SELINUX])
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Commit 8b8fcdea introduced a check for broken gcc -Wlogical-op,
but did not guard the check against non-gcc compilers, which might
lead to spurious failures when another compiler encounters an
unknown pragma. Additionally, all of our compiler warning logic
should belong in a single file, and use cache variables to allow
overriding the decision at configure time if necessary.
* configure.ac (BROKEN_GCC_WLOGICALOP): Move...
* m4/virt-compile-warnings.m4 (LIBVIRT_COMPILE_WARNINGS): ...here,
and update to modern autoconf idioms.
Commit c579d6b added a sledgehammer to silence spurious warnings from
gcc 4.2, but in the process, it also silenced useful warnings from
gcc 4.3 through 4.5. As a result, a bug slipped in to commit 0caccb58.
Tested with FreeBSD (gcc 4.2.1), RHEL 6.3 (gcc 4.4), and F17 (gcc 4.7.2),
where the former didn't trip on spurious warnings, and where the latter
two detected a revert of 2b804cf.
* m4/virt-compile-warnings.m4 (-Wno-format): Probe for the actual
spurious message, to once again allow gcc 4.4 to use -Wformat.
On RHEL 6.2, gcc 4.4.6 complains:
cc1: warning: command line option "-Wenum-compare" is valid for C++/ObjC++ but not for C
which in turn breaks a -Werror build.
Meanwhile, in Fedora 17, gcc 4.7.0, -Wenum-compare has been enhanced
to also work on C, but at the same time, it is documented that -Wall
now implicitly includes -Wenum-compare.
Therefore, it is sufficient to remove explicit checks for this option,
avoiding the warning from older gcc while still getting the
compile-time safety from newer gcc.
* m4/virt-compile-warnings.m4 (-Wenum-compare): Omit explicit check.
OpenBSD ships with gcc 4.2.1, which annoyingly treats all format
strings as though they were also attribute((nonnull)). The two
concepts are orthogonal, though, as evidenced by the number of
spurious warnings it generates on uses where we know that
virReportError specifically handles NULL instead of a format
string; worse, since we now force -Werror on git builds, it
prevents development builds on OpenBSD.
I hate to do this, as it disables ALL format checking on older
gcc, and therefore misses out on some useful checks (code that
happened to compile on Linux may still have type mismatches
when compiled on other platforms, as evidenced by the number
of times I have fixed formatting mismatches for uid_t as found
by warnings on Cygwin), but I don't see any other way to keep
-Werror alive and still compile on OpenBSD.
A more invasive change would be to make virReportError() mark
its format attribute as nonnull, and fix (a lot of) fallout;
we may end up doing that anyways as part of danpb's error
refactoring improvements, but not today.
* src/internal.h (ATTRIBUTE_FMT_PRINTF): Use preferred spellings.
* m4/virt-compile-warnings.m4 (-Wformat): Disable on older gcc.
A previous patch (c606671a) pulled in a newer version of
stat-time.h from gnulib, which causes some warnings in older gcc:
CC libvirt_driver_storage_la-storage_backend.lo
cc1: warnings being treated as errors
In file included from ../../src/storage/storage_backend.c:59:
../../gnulib/lib/stat-time.h:55: error: no previous prototype for 'get_stat_atime_ns' [-Wmissing-prototypes]
Upstream gnulib argues that these warnings are stupid (and I agree;
see <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54113>), and has
used a modern gcc feature (#pragma GCC diagnostic push) to avoid the
warning. But we still aim to compile on RHEL 6.3, with gcc 4.4.6
(not to mention even older platforms like RHEL 5), and therefore
the warning trips up our default of development with -Werror.
It took me a while to figure out how to make our set of warnings
smaller on older gcc without losing the benefit of the warnings
when using newer gcc (such as the one on Fedora 17), but this
should do the trick.
* m4/virt-compile-warnings.m4 (LIBVIRT_COMPILE_WARNINGS): Avoid
warnings that gnulib can't silence on older gcc.
The access, birth, modification and change times are added to
storage volumes and corresponding xml representations. This
shows up in the XML in this format:
<timestamps>
<atime>1341933637.027319099</atime>
<mtime>1341933637.027319099</mtime>
</timestamps>
Signed-off-by: Eric Blake <eblake@redhat.com>
While libvirt intentionally avoids -Wundef (after all, C99
guarantees sane semantics of treating undefined macros as 0),
the glibc insanity of #warning on _FORTIFY_SOURCE coupled with
what some people feel is the black magic of autoconf means
that other projects are likely to copy our snippet verbatim.
We can be nicer to other projects by making it easier to
integrate into projects that use -Wundef.
Suggested by Christophe Fergeau.
* m4/virt-compile-warnings.m4 (LIBVIRT_COMPILE_WARNINGS): Be nice
to other projects using -Wundef.
glibc 2.15 (on Fedora 17) coupled with explicit disabling of
optimization during development dies a painful death:
In file included from /usr/include/limits.h:27:0,
from /usr/lib/gcc/x86_64-redhat-linux/4.7.0/include/limits.h:169,
from /usr/lib/gcc/x86_64-redhat-linux/4.7.0/include/syslimits.h:7,
from /usr/lib/gcc/x86_64-redhat-linux/4.7.0/include/limits.h:34,
from util/bitmap.c:26:
/usr/include/features.h:314:4: error: #warning _FORTIFY_SOURCE requires compiling with optimization (-O) [-Werror=cpp]
cc1: all warnings being treated as errors
Work around this by only conditionally defining _FORTIFY_SOURCE,
in the case where glibc can actually use it. The trick is using
AH_VERBATIM instead of AC_DEFINE.
* m4/virt-compile-warnings.m4 (LIBVIRT_COMPILE_WARNINGS): Squelch
_FORTIFY_SOURCE when needed to avoid glibc #warnings.
Given that we auto-detect whether each -Wxxxx flag is supported by
GCC, and we are warning-free and use automake silent rules, there
is no compelling reason to allow compile warnings to be disabled.
Replace the --enable-compile-warnings flag with a simpler
--enable-werror flag, which defaults to 'yes' if building
from GIT, or 'no' if building from tar.gz
This helps ensure that everyone writing patches for libvirt will
take care to fix their warning problems before submitting for
review
* autobuild.sh: Force -Werror
* configure.ac: Update for LIBVIRT_COMPILE_WARNINGS macro change
* m4/virt-compile-warnings.m4: Permanently enable all warnings,
auto-enable Werror for GIT builds
Gnulib claims that there are some classes of warnings that are
worth enabling during development, but where silencing those
warnings causes code bloat that is not necessary in an optimized
build. The code bloat to silence the warnings is only enabled
by -Dlint. Follow the lead of coreutils in setting up -Dlint
whenever full warnings are requested.
* m4/virt-compile-warnings.m4 (LIBVIRT_COMPILE_WARNINGS): Add
-Dlint, and move _FORTIFY_SOURCE to config.h instead of CFLAGS.
Older gcc warns (on every file!) that -Wabi and -Wdeprecated only
make sense on C++ projects. Newer gcc accepts these warnings for
C, but it is not clear that they can do anything useful, so it
is easier to just drop the warnings altogether.
* m4/virt-compile-warnings.m4 (LIBVIRT_COMPILE_WARNINGS): Silence
-Wabi and -Wdeprecated on older gcc.
Reported by Peter Krempa.
I had previously tested commit 059d746 with -O intentionally omitted
from my CFLAGS; but that means that I missed out on this warning
from gcc 4.6.2 when optimizations are enabled:
util/buf.c: In function 'virBufferGetIndent':
util/buf.c:86:1: error: function might be candidate for attribute 'pure' [-Werror=suggest-attribute=pure]
While it is probably a good idea to add the attributes and silence
this warning, it's also invasive; 'make -k' found more than 75 such
complaints. And it doesn't help that gcc 4.6.2 is still buggy
(coreutils reported a case where gcc 4.6.2 incorrectly suggested
marking a function pure that incremented a global variable; fixed
in gcc 4.7). So the best fix for now is to disable the warning.
It also doesn't help that I stumbled across another problem - gcc
documents that -Wsuggest-attribute=pure only warns if you use -O,
or if you use -fipa-pure-const. But in practice, when I omitted -O
but added -fipa-pure-const, the warnings are fickle - I got warnings
for simple compilation that disappeared when I also added -fPIC.
And the way libtool compiles things is with -fPIC first, then without
-fPIC but with errors sent to /dev/null - which meant that without
disabling -Wsuggest-attribute=pure, I got a compile error with no
message. :( See http://debbugs.gnu.org/cgi/bugreport.cgi?bug=10197
* m4/virt-compile-warnings.m4 (LIBVIRT_COMPILE_WARNINGS): Silence
-Wsuggest-attribute warnings for now.
* .gnulib: Update to latest, for improved 'make syntax-check' and
compiler warnings.
* m4/virt-compile-warnings.m4 (LIBVIRT_COMPILE_WARNINGS):
Re-silence -Wformat-nonliteral.
* cfg.mk (_test_script_regex): Recognize our test scripts.
* gnulib/local/lib/*.diff: Drop, now that gnulib has this.
* tests/virsh-optparse: Fix use of compare.
* tests/virsh-schedinfo: Likewise.
Make virtTestLoadFile allocate the buffer to read the file into.
Fix logic error in virtTestLoadFile, stop reading on the first empty line.
Use virFileReadLimFD in virtTestCaptureProgramOutput to avoid manual
buffer handling.
Make it so we don't have to 'git add -f' particular files like
po/POTFILES.in all the time (tested by fixing one of our
special-case files as part of the patch).
* .gnulib: Update to latest.
* bootstrap: Resync from coreutils.
* .gitignore: Sort whitelist entries correctly, including ignoring
files rather than directories.
* m4/virt-compile-warnings.m4: Convert tabs to space.
With gcc 4.3.4 I'm seeing the following warning failure
cc1: warnings being treated as errors
cc1: error: -funit-at-a-time is required for inlining of functions
that are only called once [-Wdisabled-optimization]
Add -funit-at-a-time to WARN_CFLAGS.
The GCC Win32 compiler will claim to support -fstack-protector,
but if it actually gets triggered by a suitable code pattern,
linking will fail. Other non-Linux OS likely suffer the same
way with gcc.
* m4/virt-compile-warnings.m4: Only use stack protector when
the build target is Linux.
A couple of functions were declared using the old style foo()
for no-parameters, instead of foo(void)
* src/xen/xen_hypervisor.c, tests/testutils.c: Replace () with (void)
in some function declarations
* m4/virt-compile-warnings.m4: Enable -Wold-style-definition
Split the bit acinclude.m4 file into smaller pieces named
as m4/virt-XXXXX.m4
* .gitignore: Ignore gettext related files
* acinclude.m4: Delete
* m4/virt-compile-warnings.m4: Checks for GCC compiler flags
* m4/virt-pkgconfig-back-compat.m4: Backcompat check for
pkgconfig program
