report: suppress some metrics of hw owned by the host on containers

src/report/report-basic.c

@@ -581,6 +581,11 @@ static int smbios_generate(const MetricFamily *mf, sd_varlink *link, void *userd
         assert(mf && mf->name);
         assert(link);
 
+        /* SMBIOS information might be accessible from a container, but it's information about the host, not
+         * the container, hence suppress it here */
+        if (detect_container() > 0)
+                return 0;
+
         /* Reports the fundamental SMBIOS/DMI identification fields. Some of these (serial numbers, asset
          * tags, the system UUID) are privacy sensitive and only readable by root — if we lack the
          * privileges to read them we simply skip them. */
@@ -644,6 +649,10 @@ static int tpm2_generate(const MetricFamily *mf, sd_varlink *link, void *userdat
         assert(mf && mf->name);
         assert(link);
 
+        /* TPMs are not virtualized for containers, let's suppress them here */
+        if (detect_container() > 0)
+                return 0;
+
         _cleanup_(sd_device_unrefp) sd_device *dev = NULL;
         r = sd_device_new_from_subsystem_sysname(&dev, "tpmrm", "tpmrm0");
         if (r < 0) {

src/report/report-hwmon.c

@@ -14,6 +14,7 @@
 #include "report-hwmon.h"
 #include "sort-util.h"
 #include "string-util.h"
+#include "virt.h"
 
 /* The kernel's hwmon sysfs interface (see https://docs.kernel.org/hwmon/sysfs-interface.html) exposes
  * temperature sensors as temp<N>_input attributes, in millidegrees Celsius. Only the current reading is
@@ -181,6 +182,11 @@ static int hwmon_temperature_generate(const MetricFamily *mf, sd_varlink *link,
         assert(mf && mf->name);
         assert(link);
 
+        /* Temperature sensors are a hardware concept the host manages, not something specific to the systems
+         * down the container tree, hence let's not generate the metrics here, even if accessible. */
+        if (detect_container() > 0)
+                return 0;
+
         /* Note that a fresh enumerator (and hence fresh sd_device objects) is used for each call, so that
          * the sysattr cache in sd-device never hands out stale readings. */
         _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;

test/units/TEST-74-AUX-UTILS.report.sh

@@ -66,35 +66,45 @@ echo "$net_metrics" | grep '"name":"io.systemd.Network.Address"' | grep '"object
 ip address del 192.0.2.1/32 dev lo
 
 # test io.systemd.HWMon Metrics
-systemctl start systemd-report-hwmon.socket
-varlinkctl info /run/systemd/report/io.systemd.HWMon
-varlinkctl list-methods /run/systemd/report/io.systemd.HWMon
-hwmon_describe="$(varlinkctl call --more /run/systemd/report/io.systemd.HWMon io.systemd.Metrics.Describe {})"
-echo "$hwmon_describe" | jq --seq -r 'select(.name == "io.systemd.HWMon.TemperatureCelsius") | .type' | grep -wx gauge >/dev/null
-# An empty result set is signalled through the io.systemd.Metrics.NoSuchMetric sentinel error, which is what
-# VMs without any hwmon devices produce, hence treat it as success.
-hwmon_metrics="$(varlinkctl call --more --graceful=io.systemd.Metrics.NoSuchMetric /run/systemd/report/io.systemd.HWMon io.systemd.Metrics.List {})"
-# At most one row per readable, non-faulted temp<N>_input attribute in sysfs. A sensor may become
-# transiently unreadable between the two samples, hence only check the bound. VMs typically expose no hwmon
-# devices at all, in which case both counts are zero.
-hwmon_expected=0
-for f in /sys/class/hwmon/hwmon*/temp*_input; do
-    hwmon_fault="${f%_input}_fault"
-    if [[ -f "$hwmon_fault" ]] && [[ "$(cat "$hwmon_fault")" == 1 ]]; then
-        continue
+hwmon_tests() {
+    # The hwmon socket is conditioned out in containers, since temperature sensors belong to the host
+    if systemd-detect-virt --quiet --container; then
+        echo "Skipping io.systemd.HWMon tests in container."
+        return 0
     fi
-    if cat "$f" >/dev/null 2>&1; then
-        hwmon_expected=$((hwmon_expected + 1))
+
+    systemctl start systemd-report-hwmon.socket
+    varlinkctl info /run/systemd/report/io.systemd.HWMon
+    varlinkctl list-methods /run/systemd/report/io.systemd.HWMon
+    hwmon_describe="$(varlinkctl call --more /run/systemd/report/io.systemd.HWMon io.systemd.Metrics.Describe {})"
+    echo "$hwmon_describe" | jq --seq -r 'select(.name == "io.systemd.HWMon.TemperatureCelsius") | .type' | grep -wx gauge >/dev/null
+    # An empty result set is signalled through the io.systemd.Metrics.NoSuchMetric sentinel error, which is what
+    # VMs without any hwmon devices produce, hence treat it as success.
+    hwmon_metrics="$(varlinkctl call --more --graceful=io.systemd.Metrics.NoSuchMetric /run/systemd/report/io.systemd.HWMon io.systemd.Metrics.List {})"
+    # At most one row per readable, non-faulted temp<N>_input attribute in sysfs. A sensor may become
+    # transiently unreadable between the two samples, hence only check the bound. VMs typically expose no hwmon
+    # devices at all, in which case both counts are zero.
+    hwmon_expected=0
+    for f in /sys/class/hwmon/hwmon*/temp*_input; do
+        hwmon_fault="${f%_input}_fault"
+        if [[ -f "$hwmon_fault" ]] && [[ "$(cat "$hwmon_fault")" == 1 ]]; then
+            continue
+        fi
+        if cat "$f" >/dev/null 2>&1; then
+            hwmon_expected=$((hwmon_expected + 1))
+        fi
+    done
+    hwmon_reported="$(echo "$hwmon_metrics" | jq --seq -r 'select(.name == "io.systemd.HWMon.TemperatureCelsius") | .fields.sensor' | wc -l)"
+    [[ "$hwmon_reported" -le "$hwmon_expected" ]]
+    if [[ "$hwmon_reported" -gt 0 ]]; then
+        # Every row must carry a numeric value, an object and a sensor field of the form temp<N>
+        [[ "$(echo "$hwmon_metrics" | jq --seq -r 'select(.name == "io.systemd.HWMon.TemperatureCelsius") | ((.value | type) == "number") and ((.object | type) == "string") and (.fields.sensor | test("^temp[0-9]+$")) | tostring' | sort -u)" == "true" ]]
     fi
-done
-hwmon_reported="$(echo "$hwmon_metrics" | jq --seq -r 'select(.name == "io.systemd.HWMon.TemperatureCelsius") | .fields.sensor' | wc -l)"
-[[ "$hwmon_reported" -le "$hwmon_expected" ]]
-if [[ "$hwmon_reported" -gt 0 ]]; then
-    # Every row must carry a numeric value, an object and a sensor field of the form temp<N>
-    [[ "$(echo "$hwmon_metrics" | jq --seq -r 'select(.name == "io.systemd.HWMon.TemperatureCelsius") | ((.value | type) == "number") and ((.object | type) == "string") and (.fields.sensor | test("^temp[0-9]+$")) | tostring' | sort -u)" == "true" ]]
-fi
-"$REPORT" describe io.systemd.HWMon
-"$REPORT" metrics io.systemd.HWMon
+    "$REPORT" describe io.systemd.HWMon
+    "$REPORT" metrics io.systemd.HWMon
+}
+
+hwmon_tests
 
 # test io.systemd.DiskSpace Metrics
 

units/systemd-report-hwmon.socket

@@ -13,6 +13,7 @@ Documentation=man:systemd-report-hwmon@.service(8)
 DefaultDependencies=no
 Before=sockets.target shutdown.target
 Conflicts=shutdown.target
+ConditionVirtualization=!container
 
 [Socket]
 ListenStream=/run/systemd/report/io.systemd.HWMon