Hi Willy,
On 2025-02-22 10:38:51+0100, Willy Tarreau wrote:
> On Mon, Feb 17, 2025 at 10:24:11PM +0100, Thomas Weißschuh wrote:
> > On 2025-02-16 10:39:40+0100, Willy Tarreau wrote:
> > > On Wed, Feb 12, 2025 at 07:01:01PM +0100, Thomas Weißschuh wrote:
> > > > The nolibc testsuite can be run against other libcs to test for
> > > > interoperability. Some aspects of the constructor execution are not
> > > > standardized and musl does not provide all tested feature, for one it
> > > > does not provide arguments to the constructors, anymore?
> > > >
> > > > Skip the constructor tests on non-nolibc configurations.
> > >
> > > I'm not much surprised, I've always avoided arguments in my use of
> > > constructors due to a lack of portability. However the patch disables
> > > all constructors tests, while I'm seeing that the linkage_test version
> > > does not make use of arguments, though there is an implied expectation
> > > that they're executed in declaration order, which is not granted.
> >
> > The tests are written specifically to test for execution order.
> > While we can not rely on the order for other libcs, the idea was to
> > expect a given order for the nolibc implementation.
>
> OK.
>
> > > I'm wondering if we shouldn't make the tests more robust:
> > > 1) explicitly set linkage_test_constructor_test_value to zero in the
> > > declaration, because here it's not set so we have no guarantee
> > > (we're not in the kernel)
> >
> > Ack.
> >
> > > 2) only add values to check for cumulated values (e.g. |1 in const1,
> > > |2 in const2) and verify that the result is properly 3
> >
> > This would stop validating the order.
>
> That was my purpose but OK I got it. Then there's another option which
> preserves the order and even gives history:
>
> __attribute__((constructor))
> static void constructor1(void)
> {
> constructor_test_value = constructor_test_value * 0x10 + 1;
> }
>
> __attribute__((constructor))
> static void constructor2(void)
> {
> constructor_test_value = constructor_test_value * 0x10 + 2;
> }
>
> Then if executed in the right order, you'll find 0x12. If both
> are executed in any order, it will always be >= 0x10. If only one
> is executed, it will be < 0x10, and if none is executed, it's 0.
Sounds good! Do you want to write a patch?
It should also add the missing zero-initializion of
constructor_test_value.
Thomas
