Statistics file not available

[rfmoz]

OpenDKIM 2.11.0~beta2-8 Debian package has these compile options:

override_dh_auto_configure:
        CONFIG_SHELL=/bin/sh dh_auto_configure -- \
                CFLAGS="$(CFLAGS) $(CPPFLAGS)" \
                LDFLAGS="$(LDFLAGS) -Wl,-z,defs -L/usr/lib/libmilter" \
                --disable-live-testing \
                --enable-vbr \
                --enable-rbl \
                --enable-atps \
                --enable-stats \
                --enable-replace_rules \
                --enable-query_cache \
                --enable-sender_macro \
                --with-libmemcached \
                --with-openldap \
                --with-db \
                --with-sql-backend \
                --with-sasl \
                --with-domain=localhost \
                --with-lua \
                $(UNBOUND) \
                $(ODBX}

which generate this binary:

# opendkim -V
opendkim: OpenDKIM Filter v2.11.0
	Compiled with OpenSSL 3.0.11 19 Sep 2023
	SMFI_VERSION 0x1000001
	libmilter version 1.0.1
	Supported signing algorithms:
		rsa-sha1
		rsa-sha256
		ed25519-sha256
	Supported canonicalization algorithms:
		relaxed
		simple
	Active code options:
		QUERY_CACHE
		USE_DB
		USE_LDAP
		USE_LUA
		USE_ODBX
		USE_UNBOUND
		_FFR_ATPS
		_FFR_RBL
		_FFR_REPLACE_RULES
		_FFR_SENDER_MACRO
		_FFR_STATS
		_FFR_VBR
	libopendkim 2.11.0: atps query_cache

Stats looks available, but setting on the configuration file /etc/opendkim/opendkim.conf:

Statistics /var/lib/opendkim/stats.dat

Doesn't produce any stats file. Looking into the fd open by the opendkim worker process, doesn't report it on the list:

/proc/1167052/fd
├── 0 -> /dev/null
├── 1 -> /dev/null
├── 10 -> socket:[620656224]
├── 11 -> socket:[620656225]
├── 2 -> /dev/null
├── 3 -> socket:[620654469]
├── 4 -> socket:[620654477]
├── 5 -> pipe:[620654478]
├── 6 -> pipe:[620654478]
├── 8 -> socket:[620656222]
└── 9 -> socket:[620656223]

[futatuki]

I glanced the code, then it seems opendkim does not create statistics file, but fopen with "a" (append) in dkimf_stats_record() in opendkim/stats.c. Also it reports on failure by using syslog if loging is enabled. Isn't there any error log?

[futatuki]

... it seems opendkim does not create statistics file, but ...

I'm sorry, mode "a" in fopen(3) create the file if it does not exist.

[rfmoz]

Hi Futatuki,

Restarting via system only produces one line on the log:
2024-05-15T12:15:14.865994+02:00 servername opendkim[3413459]: OpenDKIM Filter v2.11.0 starting (args: -x /etc/opendkim/opendkim.conf)

Executing the same instruction via strace, doesn't report any reference, good or bad, to the stats file:
strace -f /usr/sbin/opendkim -x /etc/opendkim/opendkim.conf

[thegushi]

Thanks for the detailed report and the strace output -- that is helpful.

A quick question first: is this server running in signing-only mode (outbound mail), or is it also verifying inbound mail?

The reason we ask: the Statistics feature only records data for messages going through DKIM verification. The recording happens in dkimf_stats_record(), which is only called when a verification handle exists. For a signing-only server, that handle is never created, so the stats file is never touched -- which would explain exactly what you are seeing, including the clean strace output.

More broadly, the FFR prefix on a feature flag stands for 'For Future Release' -- these are features that are wired up but not finished, and should not be relied on in production. The Statistics feature in particular appears to have been implemented only for the verification path and never extended to cover signing. That is a known gap rather than a bug per se, and fixing it properly would require a meaningful rework rather than a small patch.

If you confirm the signing-only setup, we will close this as a known limitation of an incomplete feature.