[libraries][regression] ld_so_cache directory listing not further collected

[pmoravec]

https://github.com/sosreport/sos/blob/main/sos/report/plugins/libraries.py#L47-L50 does not collect any directory listing.

Originally, it called "ls -lanH %s" % " ".join(dirs), which worked well - but add_dir_listing method treats the f"{' '.join(dirs)}" as a string and it attempts to verify existence of the whole string as a filepath (https://github.com/sosreport/sos/blob/main/sos/report/plugins/__init__.py#L2094) before collecting anything, which returns in no-op.

Trivial patch would be:

self.add_dir_listing(
                list(dirs),
                suggest_filename='ld_so_cache'
)

to collect dir.listing for each and every path - separately, causing there will be files sos_commands/libraries/ld_so_cache, sos_commands/libraries/ld_so_cache.1, sos_commands/libraries/ld_so_cache.2,.. generated. Not ideal either. Removing suggest_name is an option, to have generated files like sos_commands/libraries/ls_-alZ_.lib64 or sos_commands/libraries/ls_-alZ_.usr.lib64.pipewire-0.3.jack.

Yet better approach would be adding an option list_all to add_dir_listing to suppress separating the list of paths into individual calls of tree/ls commands. Or, alternatively, call ls -alZ directly from the libraries plugin.

The ld_so_cache is a bit traditional / old functionality where I am unsure if we should stick to the collection precisely, or if it is obsolete request. So I dont know what are the preferences. Maybe @rmetrich as the original author can suggest..?