LTP: fix test case writev06 issue

[shaikshavali1]

Below issues are found in this test case:

1. mmap is failing with EBADF error if we pass 0 as file descriptor
   with MAP_ANONYMOUS option.
2. TPASS message is tagged as INFO message.
   Below modifications are performed.
3. Modified the test case to pass -1 as a file descriptor value
   while invoking mmap.
4. Modified the print message TAG to TPASS.

[davidchisnall]

I think the third bullet point is a real bug (@SeanTAllen, can you take a look?). In POSIX it is undefined what happens when you MAP_ANONYMOUS with an fd that is not -1, but Linux ignores the fd argument (XNU uses it as a metadata parameter to attach to the mapped region). We are not compatible with Linux if we are treating -1 as special and should fix that in our mmap routine.

[SeanTAllen]

@davidchisnall here's the code:

    // Anonymous mapping/allocation
    else if (fd == -1 && (flags & MAP_ANONYMOUS))
    {
        return (long)enclave_mmap(addr, length, flags & MAP_FIXED, prot, 1);
    }

So yes, MAP_ANONYMOUS is only supported currently if the fd is -1.

Shall we change to ignore the fd entirely?

[SeanTAllen]

@davidchisnall assuming a yes, I went ahead and created lsds/sgx-lkl#755

[davidchisnall]

@shaikshavali1, please revert the corresponding changes in this PR. @hukoyu, once lsds/sgx-lkl#755 is merged, please go ahead and merge the version of this without those changes.

[SeanTAllen]

lsds/sgx-lkl#755 has been merged.

[hukoyu]

Submitted PR lsds/sgx-lkl#765 to enable this test as is without patch and it is passing. This patch not needed anymore. Closing.