tests: measure kernel properties across tests

spread.yaml

@@ -425,6 +425,10 @@ debug-each: |
         cat "$RUNTIME_STATE_PATH/runs" || true
     fi
 
+measure-each: |
+    # shellcheck source=tests/lib/measure.sh
+    "$TESTSLIB/measure.sh" kernel
+
 rename:
     # Move content into a directory, so that deltas computed by repack benefit
     # from the content looking similar to codeload.github.com.

tests/lib/measure.sh

@@ -0,0 +1,94 @@
+#!/bin/sh -eux
+
+# Measurement format, increment when making changes and hacking on this script
+# on a target using spread -reuse.
+F=0
+
+# Prepare per-measurement directory
+M="/tmp/.measure.format-$F"
+
+mkdir -p "$M"
+N=$(test -s "$M/.n" && cat "$M/.n" || echo 0)
+mkdir -p "$M/run-$N"
+cd "$M/run-$N"
+
+while [ "$#" -gt 0 ]; do
+	case "$1" in
+		kernel)
+			# Measure: kernel version, module list, mount table, process list and sysctl settings
+			command -v uname && uname -a > kernel.version
+			command -v lsmod && lsmod | (
+			# can be started by systemd automount unit.
+			grep -E -v '^binfmt_misc ' |
+				cat
+			) > kernel.modules
+			test -f /proc/self/mountinfo && cat /proc/self/mountinfo | (
+				grep -E -v '^[[:digit::]]+ [[:digit:]]+ 0:40 / /proc/sys/fs/binfmt_misc rw,relatime shared:[[:digit:]]+ - binfmt_misc binfmt_misc rw$' |
+				cat
+			) > kernel.mountinfo
+			command -v ps -A -o pid,comm > kernel.procs
+			command -v sysctl && sysctl -a | (
+				grep -E -v '^fs.dentry-state = ' |
+				grep -E -v '^fs.file-nr = ' |
+				grep -E -v '^fs.inode-nr = ' |
+				grep -E -v '^fs.inode-state = ' |
+				grep -E -v '^kernel.ns_last_pid = ' |
+				grep -E -v '^kernel.random.entropy_avail = ' |
+				grep -E -v '^kernel.random.uuid = ' |
+				grep -E -v '^kernel.sched_domain.cpu[[:digit:]]+.domain[[:digit:]].max_newidle_lb_cost = ' |
+				cat
+			)> kernel.sysctl
+			;;
+
+		apparmor)
+			# Measure: loaded apparmor profiles
+			# NOTE: the structure of the path is very significant, including the trailing dot.
+			test -d /sys/kernel/security/apparmor/policy/. && tar --mtime=/ -cf lsm.apparmor.tar /sys/kernel/security/apparmor/policy/.
+			;;
+
+		packages)
+			# Measure: installed packages
+			command -v dpkg && dpkg --get-selections | sort > packages.deb
+			command -v rpm && rpm -qa | sort > packages.rpm
+			command -v snap && snap list --all --color=never --unicode-never | sort > packages.snap
+			;;
+
+		systemd)
+			# Measure: systemd units. Because spread uses ssh and ssh creates user
+			# sessions filter out differences is session-NNN.scope. Due to the nature of
+			# CPU scaling  the "ondemand" service may change at any time it is filtered
+			# out.
+			command -v systemctl && systemctl list-units --full | (
+			grep -E -v '^session-[[:digit:]]+\.scope' |
+				grep -E -v '^user-[[:digit:]]+\.slice' |
+				grep -E -v '^ondemand.service' |
+				grep -E -v '^online.service' |
+				cat
+			) > systemd.units
+			command -v systemctl && systemctl list-jobs --full | > systemd.jobs
+			command -v systemctl && systemctl list-timers --full | > systemd.timers
+			;;
+
+		files)
+			# Measure: interesting directories.
+			command -v tar && test -d /etc && tar --mtime=/ -cf files.etc.tar /etc/
+			command -v tar && test -d /dev && tar --mtime=/ -cf files.dev.tar /dev/
+			command -v tar && test -d /boot && tar --mtime=/ -cf files.boot.tar /dev/
+			command -v tar && test -d /home && tar --mtime=/ -cf files.home.tar /home/
+			;;
+		*)
+			echo "unknown measurement: $1"
+			exit 1
+			;;
+	esac
+	shift
+done
+
+# Ensure we are not deviated
+if [ "$N" -gt 0 ]; then
+	diff -ur "$M/run-0" "$M/run-$N"
+fi
+
+# Store counter if we didn't fail
+echo "$((N + 1))" > "$M/.n"
+