The metric list is built with conf_files_list_strv(), but each metric's
value is then looked up again by walking report_files_dirs[] by hand,
and the two disagreed whenever an earlier directory had an entry that is
not a regular file:
- conf_files_list_strv() skipped such an entry and listed the one from
a later directory, so the metric was advertised by Describe();
- file_metric_generate() only moved on to the next directory on
-ENOENT, so it hit the non-regular entry, logged a warning and
produced nothing.
The practical case is masking a vendor-supplied entry with a symlink to
/dev/null: the metric kept being described, was never listed, and every
scrape logged "Failed to open ..., skipping: File descriptor in bad
state".
Honour masks in the enumeration via CONF_FILES_FILTER_MASKED_BY_SYMLINK,
as other conf dirs do, and make the lookup skip non-regular entries the
same way the enumeration does. Document the masking in the man page and
cover both cases in TEST-74-AUX-UTILS.report.
(cherry picked from commit 08be8677539642f45c6127085283cf08b6a410b7)
Armaan Sandhu
f41defc034