Make swap size configurable

buildroot-external/rootfs-overlay/usr/lib/systemd/system/etc-default.mount

@@ -0,0 +1,13 @@
+[Unit]
+Description=Persistent /etc/default directory
+Requires=mnt-overlay.mount
+After=mnt-overlay.mount
+
+[Mount]
+What=/mnt/overlay/etc/default
+Where=/etc/default
+Type=None
+Options=bind
+
+[Install]
+WantedBy=hassos-bind.target

buildroot-external/rootfs-overlay/usr/lib/systemd/system/haos-swapfile.service

@@ -1,8 +1,8 @@
 [Unit]
 Description=HAOS swap
 DefaultDependencies=no
-Requires=mnt-data.mount
-After=mnt-data.mount [email protected]
+Requires=etc-default.mount mnt-data.mount
+After=etc-default.mount mnt-data.mount [email protected]
 Before=mnt-data-swapfile.swap
 
 [Service]

buildroot-external/rootfs-overlay/usr/lib/systemd/system/mnt-data-swapfile.swap

@@ -1,5 +1,6 @@
 [Unit]
 Description=HAOS swap file
+ConditionFileNotEmpty=/mnt/data/swapfile
 
 [Swap]
 What=/mnt/data/swapfile

buildroot-external/rootfs-overlay/usr/libexec/haos-swapfile

@@ -1,24 +1,59 @@
 #!/bin/sh
 set -e
 
-swapfile="/mnt/data/swapfile"
+size2kilobytes() {
+	bytes="$(echo "$1" | awk \
+	  'BEGIN{IGNORECASE = 1}
+	   function tobytes(n,b,p) {printf "%u\n", n*b^p/1024}
+	   /[0-9]B?$/{tobytes($1,  1, 0); next};
+	   /K(i?B)?$/{tobytes($1,  2, 10); next};
+	   /M(i?B)?$/{tobytes($1,  2, 20); next};
+	   /G(i?B)?$/{tobytes($1,  2, 30); next};
+	   {print -1}')"
+	echo "$bytes"
+}
+
+if [ -f /etc/default/haos-swapfile ]; then
+    # shellcheck disable=SC1091
+    . /etc/default/haos-swapfile
+fi
+SWAPFILE="/mnt/data/swapfile"
+
+# Swap size in kilobytes (as it's also what meminfo shows)
+SWAPSIZE="$(size2kilobytes "${SWAPSIZE}")"
+
+if [ -z "${SWAPSIZE}" ] || [ "${SWAPSIZE}" = "-1" ]; then
+	# Default to 33% of total memory
+	SWAPSIZE="$(awk '/MemTotal/{ print int($2 * 0.33) }' /proc/meminfo)"
+	echo "[INFO] Using default swapsize of 33% RAM (${SWAPSIZE} kB)"
+fi
+
 # Swap space in 4k blocks
-swapsize="$(awk '/MemTotal/{ print int($2 * 0.33 / 4) }' /proc/meminfo)"
+SWAPSIZE_BLOCKS=$((SWAPSIZE / 4))
 
+if [ "${SWAPSIZE_BLOCKS}" -lt 10 ]; then
+    echo "[INFO] Requested swap size smaller than 40kB, disabling swap"
 
-if [ ! -s "${swapfile}" ] || [ "$(stat "${swapfile}" -c '%s')" -lt $((swapsize * 4096)) ]; then
-	# Check free space (in 4k blocks)
-	if [ "$(stat -f /mnt/data -c '%f')" -lt "${swapsize}" ]; then
-		echo "[WARNING] Not enough space to allocate swapfile"
-		exit 1
-	fi
+    if [ -f "${SWAPFILE}" ]; then
+        echo "[INFO] Removing existing swapfile"
+        rm -f "${SWAPFILE}"
+    fi
 
-	echo "[INFO] Creating swapfile of size $((swapsize *4))k"
-	umask 0077
-	dd if=/dev/zero of="${swapfile}" bs=4k count="${swapsize}"
+    exit 0
 fi
 
-if ! swaplabel "${swapfile}" > /dev/null 2>&1; then
-	/usr/lib/systemd/systemd-makefs swap "${swapfile}"
+if [ ! -s "${SWAPFILE}" ] || [ "$(stat "${SWAPFILE}" -c '%s')" -ne $((SWAPSIZE_BLOCKS * 4096)) ]; then
+    # Check free space (in 4k blocks)
+    if [ "$(stat -f /mnt/data -c '%f')" -lt "${SWAPSIZE_BLOCKS}" ]; then
+        echo "[ERROR] Not enough space to allocate swapfile"
+        exit 1
+    fi
+
+    echo "[INFO] Creating swapfile of size ${SWAPSIZE} kB (rounded to ${SWAPSIZE_BLOCKS} blocks)"
+    umask 0077
+    dd if=/dev/zero of="${SWAPFILE}" bs=4k count="${SWAPSIZE_BLOCKS}"
 fi
 
+if ! swaplabel "${SWAPFILE}" > /dev/null 2>&1; then
+    /usr/lib/systemd/systemd-makefs swap "${SWAPFILE}"
+fi

tests/smoke_test/test_basic.py

@@ -78,6 +78,31 @@ def test_systemctl_check_no_failed(shell):
     assert "0 loaded units listed." in output, f"Some units failed:\n{"\n".join(output)}"
 
 
+@pytest.mark.dependency(depends=["test_init"])
+def test_custom_swap_size(shell, target):
+    output = shell.run_check("stat -c '%s' /mnt/data/swapfile")
+    # set new swap size to half of the previous size - round to 4k blocks
+    new_swap_size = (int(output[0]) // 2 // 4096) * 4096
+    shell.run_check(f"echo 'SWAPSIZE={new_swap_size/1024/1024}M' > /etc/default/haos-swapfile; reboot")
+    # reactivate ShellDriver to handle login again
+    target.deactivate(shell)
+    target.activate(shell)
+    output = shell.run_check("stat -c '%s' /mnt/data/swapfile")
+    assert int(output[0]) == new_swap_size, f"Incorrect swap size {new_swap_size}B: {output}"
+
+
+@pytest.mark.dependency(depends=["test_custom_swap_size"])
+def test_no_swap(shell, target):
+    output = shell.run_check("echo 'SWAPSIZE=0' > /etc/default/haos-swapfile; reboot")
+    # reactivate ShellDriver to handle login again
+    target.deactivate(shell)
+    target.activate(shell)
+    output = shell.run_check("systemctl --no-pager -l list-units --state=failed")
+    assert "0 loaded units listed." in output, f"Some units failed:\n{"\n".join(output)}"
+    swapon = shell.run_check("swapon --show")
+    assert swapon == [], f"Swapfile still exists: {swapon}"
+
+
 @pytest.mark.dependency(depends=["test_init"])
 def test_kernel_not_tainted(shell):
     """Check if the kernel is not tainted - do it at the end of the