Re: [Gnu-arch-users] Re: tla get --hard-links available

[Davide Libenzi]

On Fri, 3 Oct 2003, Andrea Arcangeli wrote:

> watch the above mkdir, that's totally broken, that's an _open_ w/o the
> LD_PRELOAD set! Sounds very risky to enable it ;)

It seems that the loader/strace have problems. For files outside the
FLCOW_PATH (/proc/... likely) the library is simply a pass through. You
can look at the code, it's about 100 lines of trivial code. I'm running it
on my desktop with FLCOW_PATH=/home/davide/arch-projects and it works
flawlessy here.



> the IP where it crashes is this (provided by the kernel via `dmesg`, much
> easier than gdb core dump ;):
>
> ps[21959]: segfault at 0000000000000000 rip 0000002a9583563c rsp 
> 0000007fbfffe740 error 4
> cat[21967] trap invalid operand rip:7fbfffeaba rsp:7fbfffe6a8 error:0
>
> I attached the assembly of the library. By mixing the rip (equivalent of eip)
> with the results of the mmap call and elf offsets, it's possible to find the C
> code that crashed. But it takes too much time so I'm postponing this for next
> week. If you want to go ahead you're welcome! ;)

The fault rip is outside of the [MAP address, += library size] range :(
Can you :

# nm /lib64/libc.so.6 | grep open



- Davide