xrdcp scrambles destination path

[rodwalker]

Hi,
On CentOS7, and using the file:// prefix for the destination, when the path is long it gets scrambled. xrdcp has zero exitcode but the file is in some random place(but determined by dest path).

xrdcp -vf root://atlasxrootd-kit.gridka.de:1094//pnfs/gridka.de/atlas/disk-only/atlasdatadisk/rucio/mc16_13TeV/26/a8/HITS.14859379._044566.pool.root.1 file:///tmp/walkerr/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/mc16_13TeV/1234567890123
[73.94MB/73.94MB][100%][==================================================][36.97MB/s]
[lxplus080] rucio $ ls -l /tmp/walkerr/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/mc16_13TeV/1234567890123
ls: cannot access /tmp/walkerr/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/mc16_13TeV/1234567890123: No such file or directory

One character less on the destination works
file:///tmp/walkerr/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/mc16_13TeV/123456789012
This is 128 chars which might be suspicious.

Also removing 'file://' works. Above is the case for
/cvmfs/atlas.cern.ch/repo/ATLASLocalRootBase/x86_64/xrootd/4.8.5-x86_64-centos7/v4.8.5/bin/xrdcp

With
/cvmfs/atlas.cern.ch/repo/ATLASLocalRootBase/x86_64/xrootd/4.9.0-x86_64-centos7/v4.9.0/bin/xrdcp
it fails with dest
/tmp/walkerr/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/mc16_13TeV/HITS.14859379._044566.pool.root.1.part
but I don`t find a simple string length threshold.
This file is written to
/tmp/walkerr/d1234567890/d1234567890/d1234567890/d1234567890/d1234567890/7890/d1234567890/mc16_13TeV/HITS.148593794859379._044566.pool.root.1.part

NB. scrambled at /7890/

On SL6, both respective versions work, eg.
/cvmfs/atlas.cern.ch/repo/ATLASLocalRootBase/x86_64/xrootd/4.9.0-x86_64-slc6/v4.9.0/bin/xrdcp

I am not sure if 'file://' is even fully supported, so we will remove that anyway. It is not in the man page, but mostly works. I think it should be fixed or formally dropped and give an error.

Cheers,
Rod.

[simonmichal]

Hi Rod,

Thank you for reporting this problem. Regarding your question whether we support file://: yes we do.

The problem is that in here:

xrootd/src/XrdApps/XrdCpFile.cc

Line 102 in 0421cef

else if (*pP == '/') strcpy(Path, pP);

the parameters of strcpy are overlapping buffers which results with undefined behaviour (probably strcpy implementation on slc6 is bit different and that's why it works on slc6).

I will push a bugfix on Monday and include it in next bugfix release.

Again, thanks for reporting!

Cheers,
Michal