Re: [libvirt] [PATCH v2] util: forbid freeing const pointers

Now that we've finally fixed all the violators, it's time to enforce that any pointer to a const object is never freed (it is aliasing some other memory, where the non-const original should be freed instead). Alas, the code still needs a normal vs. Coverity version, but at least we are still guaranteeing that the macro call evaluates its argument exactly once. I verified that we still get the following compiler warnings, which in turn halts the build thanks to -Werror on gcc (hmm, gcc 4.8.3's placement of the ^ for ?: type mismatch is a bit off, but that's not our problem): int oops1 = 0; VIR_FREE(oops1); const char *oops2 = NULL; VIR_FREE(oops2); struct blah { int dummy; } oops3; VIR_FREE(oops3); util/virauthconfig.c:159:35: error: pointer/integer type mismatch in conditional expression [-Werror] VIR_FREE(oops1); ^ util/virauthconfig.c:161:5: error: passing argument 1 of 'virFree' discards 'const' qualifier from pointer target type [-Werror] VIR_FREE(oops2); ^ In file included from util/virauthconfig.c:28:0: util/viralloc.h:79:6: note: expected 'void *' but argument is of type 'const void *' void virFree(void *ptrptr) ATTRIBUTE_NONNULL(1); ^ util/virauthconfig.c:163:35: error: type mismatch in conditional expression VIR_FREE(oops3); ^ * src/util/viralloc.h (VIR_FREE): No longer cast away const. * src/xenapi/xenapi_utils.c (xenSessionFree): Work around bogus header. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- v2: this depends on the existing 1/4, while being a replacement to all of 2-4/4 at once. https://www.redhat.com/archives/libvir-list/2014-July/msg00716.html src/util/viralloc.h | 11 +++++------ src/xenapi/xenapi_utils.c | 4 +++- 2 files changed, 8 insertions(+), 7 deletions(-)