On Fri, Jan 24, 2020 at 12:46:12AM +0500, ???? ??????? wrote:
> > diff --git a/Makefile b/Makefile
> > index 8399f6ca35..4757bc77e6 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -199,6 +199,7 @@ SPEC_CFLAGS += $(call cc-opt,-Wshift-negative-value)
> > SPEC_CFLAGS += $(call cc-opt,-Wshift-overflow=2)
> > SPEC_CFLAGS += $(call cc-opt,-Wduplicated-cond)
> > SPEC_CFLAGS += $(call cc-opt,-Wnull-dereference)
> > +SPEC_CFLAGS += $(call cc-opt,-Walloc-size-larger-than=-1)
> >
>
>
> CC src/cfgparse.o
> src/cfgparse.c: In function 'check_config_validity':
> src/cfgparse.c:3642:33: warning: product '2147483648 * 8' of arguments 1
> and 2 exceeds 'SIZE_MAX' [-Walloc-size-larger-than=]
Pfff.... The only good news is that it takes -1 as SIZE_MAX.
> newsrv->idle_orphan_conns = calloc((unsigned int)global.nbthread,
> sizeof(*newsrv->idle_orphan_conns));
>
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> src/cfgparse.c:3642:33: note: argument 1 in the range [2147483648,
> 4294967295]
(...)
> why is it complaining about "product '2147483648 * 8" ?
because calloc multiplies the two fields and gcc decided that the largest
value we could possibly pass to the first one if we were as stupid as it
is is 2147483648. Interestingly it took the largest negative value turned
to positive and ignored the positive ones that can be turned to the second
half that are negative if nbthread was negative.
I really think this test is totally bogus and that there is no way to
express it correctly. I mean, gcc only lets us use 8, 16, 32 or 64 bits.
If you need to calloc a few megabytes, you'll be forced to apply a mask
to the value just to shut it up, and *create* the overflow problem yourself
when it didn't exist.
Let's give up on this one if it doesn't cause too much trouble to you.
Otherwise we might cheat doing this :
calloc((unsigned short)global.nbthread, ...)
But I really despise this given that we have to make the code wrong just
to please this shitty compiler.
Willy
