codex: initial commit

!!! This code is a very quick hack I made in an evening of
!!! inspired curiosity, the code should be considered of junk
!!! quality.

Codex aspires to be a read-only FUSE interface to the journal
provided by systemd.

At this point it only implements simple reading of the journal
through a single match filter selected via filesystem path.

With codex mounting the journal @ /mnt, you can see what
fields are available for matching against via:

`ls /mnt/by-field`

This returns a list of fields as directories, which you can then
list the contents of to see all the unique values present for the
repsective field, returned as regular files:

`ls /mnt/by-field/UNIT`

Then by reading one of the returned files, you read the contents
of the journal filtered on the respective field and value, e.g.:

`cat /mnt/by-field/UNIT/apt-daily.timer`

and you'll get a stream of all the data in the journal with a
filter of UNIT=apt-daily.timer

With some work, this could be made more advanced supporting
combined filters, perhaps in the form of:

`cat /mnt/by-field/UNIT/apt-daily.timer/and/by-field/PRIORITY/3/all`

As-is, the path by-field/UNIT/apt-daily.timer is a regular file,
so no such constructions are possible.  But if it were changed to
be another directory, where you can select further matches by
traversing yet another and/by-field subpath, where all the fields
are available (or maybe only the matching subset of fields if
feasible), then more complex uses could be satisfied.  Imagine
or/by-field and and/by-field being available under every value's
directory.

Note this commit includes a barely functioning PoC.  It is not
intended for production, but you can already use it to navigate
journals in a way I find more pleasant than journalctl.

I think it'd be great to have a tool like this built out with all
the bells and whistles.  It may make sense to roll something
similar into journalctl like `journalctl --mount /mnt/point`.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
new file mode 100644
index 0000000..29477df
--- /dev/null
+++ b/src/Makefile.am
@@ -0,0 +1,2 @@
+bin_PROGRAMS = codex
+codex_SOURCES = codex.c