Re: [LTP] pidns31: fix EACCESS error in mq_open()

[Sukadev B. <su...@li...>]

Garrett Cooper [yan...@gm...] wrote:
| On Wed, Aug 4, 2010 at 4:52 PM, Sukadev Bhattiprolu
| <su...@li...> wrote:
| >
| > pidns31: mq_open() fails with EACCESS.
| >
| > pidns31 test case fails with EACCESS - due to the leading '/' in
| > mqname. See comments in the patch below for details.
| >
| > Signed-off-by: Sukadev Bhattiprolu <su...@li...>
| > ---
| > Index: testcases/kernel/containers/pidns/pidns31.c
| > ===================================================================
| > RCS file: /cvsroot/ltp/ltp/testcases/kernel/containers/pidns/pidns31.c,v
| > retrieving revision 1.6
| > diff -u -p -r1.6 pidns31.c
| > --- testcases/kernel/containers/pidns/pidns31.c 14 Nov 2009 23:58:26 -0000      1.6
| > +++ testcases/kernel/containers/pidns/pidns31.c 4 Aug 2010 23:24:54 -0000
| > @@ -61,7 +61,14 @@
| >  char *TCID = "pidns31";
| >  int TST_TOTAL = 1;
| >
| > -char *mqname = "/mq1";
| > +
| > +/*
| > + * NOTE: The mq_open() interface in glibc requires mqname to start with a '/'
| > + *      and the glibc call skips the leading '/' when invoking the system
| > + *      call. Since we bypass the glibc mq_open() (and use syscall()) we
| > + *      define mqname without the leading '/'.
| > + */
| > +char *mqname = "mq1";
| >  int result = TFAIL;
| >
| >  int errno;
| > @@ -264,6 +271,7 @@ int main(int argc, char *argv[])
| >        }
| >
| >        syscall(__NR_mq_unlink, mqname);
| > +
| >        mqd = syscall(__NR_mq_open, mqname, O_RDWR|O_CREAT|O_EXCL, 0777, NULL);
| >        if (mqd == (mqd_t)-1) {
| >                tst_resm(TBROK, "parent: mq_open() failed (%s)",
| 
| Did Linux become non-POSIX compliant :) (from
| <http://www.opengroup.org/onlinepubs/000095399/functions/mq_open.html>)?

Heh. Good question but I think the mq_open() from glibc is compliant
with this. I am just not sure if the call via syscall() needs to be
compliant.

But if that is a concern, we need a separate a test case for that -
pidns31 is using mq_* to test an unrelated feature. I think would
make sense to apply this fix, allowing LTP to test the feature even
on older distros.

Or pidns31 can go back to using the library interface and we could
skip the test on old distros.

Sukadev.