Callers of the 'udev monitor' tool expect to see output when
an event occurs. The stdio buffering defeats that. This patch
switches it to line buffering.
In the Cockpit integration tests we hang onton the journal files
for a failed test and would like to inspect them using coredumpctl.
This commit adds the ability to specify an alternate directory
for coredumpctl to read the journal from.
Previously the following command:
$ journalctl -f -t unmatchedtag12345
... would block when called with criteria that did not match any
journal lines. Once log lines appeared that matched the criteria
they were displayed.
Commit 02ab86c732 broke this
behavior and the journal was not followed, but the command
exits with '-- No entries --' displayed.
This commit fixes the issue.
More information downstream:
https://bugzilla.redhat.com/show_bug.cgi?id=1253649