[XrdCl] Only use the passwd file if a valid entry is found

[chrisburr]

When using XRootD 5.2 in CERN OpenShift I've seen the following segfault in gfal2:

[2021-05-25 12:29:06.201028 +0000][Debug  ][Utility           ] Initializing xrootd client version: v5.2.0
[2021-05-25 12:29:06.201312 +0000][Warning][Utility           ] Unable to process global config file: [ERROR] OS Error: no such file or directory
[2021-05-25 12:29:06.201378 +0000][Debug  ][Utility           ] Unable to find user home directory.
[2021-05-25 12:29:06.201553 +0000][Debug  ][PlugInMgr         ] Initializing plug-in manager...
[2021-05-25 12:29:06.201563 +0000][Debug  ][PlugInMgr         ] No default plug-in, loading plug-in configs...
[2021-05-25 12:29:06.201585 +0000][Debug  ][PlugInMgr         ] Processing plug-in definitions in /etc/xrootd/client.plugins.d...
[2021-05-25 12:29:06.201596 +0000][Debug  ][PlugInMgr         ] Unable to process directory /etc/xrootd/client.plugins.d: [ERROR] OS Error: no such file or directory

Thread 1 "python" received signal SIGSEGV, Segmentation fault.
0x00007f60553dd5d8 in XrdCl::PlugInManager::ProcessEnvironmentSettings() () from /tmp/env/lib/gfal2-plugins//../libXrdCl.so.3

The issue is that the user ID is randomised and is therefore missing from the /etc/passwd file and it looks like 5975094 forgot to invert the if condition. Presumably this also causes another bug with user plugins being ignored.

[simonmichal]

Thanks!

[chrisburr]

Does anything need to be done to backport this to the 5.2.x branch?

[simonmichal]

No need to do anything special, I will handle it once we have enough fixes to cut 5.2.1.