Seems recent versions of Coverity have (mostly) resolved the issue using
ternary operations in VIR_FREE (and now VIR_DISPOSE*) macros. So let's
just remove it and if necessary handle one off issues as the arise.
For a few cases where we handle secret information it's good to clear
the buffers containing sensitive data before freeing them.
Introduce VIR_DISPOSE, VIR_DISPOSE_N and VIR_DISPOSE_STRING that allow
simple clearing fo the buffers holding sensitive information on cleanup
paths.
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@redhat.com>
In fact, the suffix should be _QUIET not _QUIT to stress the
fact, that no OOM error is reported on error.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
VIR_APPEND_ELEMENT(array, size, elem) was not safe if the expression
for 'size' had side effects. While no one in the current code base
was trying to pass side effects, we might as well be robust and
explicitly document our intentions.
* src/util/viralloc.c (virInsertElementsN): Add special case.
* src/util/viralloc.h (VIR_APPEND_ELEMENT): Use it.
(VIR_ALLOC, VIR_ALLOC_N, VIR_REALLOC_N, VIR_EXPAND_N)
(VIR_RESIZE_N, VIR_SHRINK_N, VIR_INSERT_ELEMENT)
(VIR_DELETE_ELEMENT, VIR_ALLOC_VAR, VIR_FREE): Document
which macros are safe in the presence of side effects.
* docs/hacking.html.in: Document this.
* HACKING: Regenerate.
Signed-off-by: Eric Blake <eblake@redhat.com>
The Coverity static analyzer was generating many false positives for the
unary operation inside the VIR_FREE() definition as it was trying to evaluate
the else portion of the "?:" even though the if portion was (1).
Signed-off-by: Eric Blake <eblake@redhat.com>
