Add hacky iSCSI implementation

.github/workflows/build-fedora.sh

@@ -294,7 +294,8 @@ for phase in "${PHASES[@]}"; do
             INITRD="initrd_$KVER.cpio.zstd"
             mkosi --cache "$MKOSI_CACHE" \
                   --default fedora.mkosi \
-                  --package="NetworkManager,iscsi-initiator-utils" \
+                  --package="iscsi-initiator-utils,systemd-networkd" \
+                  --extra-tree=mkosi.extra-iscsi \
                   --image-version="$KVER" \
                   --environment=KERNEL_VERSION="$KVER" \
                   --output="$INITRD" \
@@ -312,6 +313,7 @@ for phase in "${PHASES[@]}"; do
                   --distribution="$ID" \
                   --release="$VERSION_ID" \
                   --format=gpt_btrfs \
+                  --package="iscsi-initiator-utils" \
                   --output=rootfs.img
             popd
 
@@ -333,7 +335,7 @@ for phase in "${PHASES[@]}"; do
             dnsmasq --interface=initrd0 --bind-interfaces --dhcp-range=10.10.10.10,10.10.10.100
             grep -q initrd0 /etc/qemu/bridge.conf || echo "allow initrd0" >>/etc/qemu/bridge.conf
 
-            iscsi_cmdline="ip=dhcp netroot=iscsi:10.10.10.1::::$target_name"
+            iscsi_cmdline="ip=dhcp netroot=iscsi:10.10.10.1::::$target_name rd.systemd.wants=systemd-networkd.service rd.systemd.wants=systemd-networkd-wait-online.service"
             timeout --foreground -k 10 5m \
                 qemu-kvm -m 1024 -smp "$(nproc)" -nographic -nic bridge,br=initrd0 \
                          -initrd "$INITRD" \

.github/workflows/build_test.yml

@@ -35,7 +35,7 @@ jobs:
           - INITRD_LVM
           - INITRD_LUKS
           - INITRD_LUKS_LVM
-            #- INITRD_ISCSI # iSCSI is missing a generator
+          - INITRD_ISCSI
           - SYSEXT
     container:
       image: "${{ matrix.distro.name }}:${{ matrix.distro.tag }}"

mkosi.extra-iscsi/usr/lib/systemd/system-generators/iscsi-generator.sh

@@ -0,0 +1,98 @@
+#!/bin/bash
+set -e
+
+# Format:
+#       root=iscsi:[<servername>]:[<protocol>]:[<port>]:[<LUN>]:<targetname>
+#       [root=*] netroot=iscsi:[<servername>]:[<protocol>]:[<port>]:[<LUN>]:<targetname>
+#
+# root= takes precedence over netroot= if root=iscsi[...]
+
+# Example:
+# netroot=iscsi:10.10.10.1::::iqn.2022-01.com.example:iscsi.initrd.test
+# /dev/disk/by-path/ip-10.10.10.1:3260-iscsi-iqn.2022-01.com.example:iscsi.initrd.test-lun-1
+# /dev/disk/by-path/ip-10.10.10.1:3260-iscsi-iqn.2022-01.com.example:iscsi.initrd.test-lun-1-part1
+# /dev/disk/by-path/ip-<servername>:<port>-iscsi-<lun>-<targetname>-lun-<lun>
+
+root=
+specs=()
+
+cmdline="${SYSTEMD_PROC_CMDLINE:-$(cat /proc/cmdline)}"
+
+for arg in $cmdline; do
+    if [[ $arg == "root="* ]]; then
+        # The last root= assignment wins.
+        root="${arg#*=}"
+    elif [[ $arg == "netroot=iscsi:"* ]]; then
+        value="${arg#*=}"
+        # All netroot= invocations matter.
+        specs+=( "$value" )
+
+        if [ -z "$root" ]; then
+            root="$value"
+        fi
+    fi
+done
+
+if [[ $root == "iscsi:"* ]]; then
+    specs+=( "$root" )
+fi
+
+if [ ${#specs[@]} -eq 0 ]; then
+    # nothing for us to do
+    exit 0
+fi
+
+make_unit() {
+    # Handle the root= argument
+    if [[ $root == "iscsi:" ]]; then
+        : # TODO
+    fi
+
+    service="${dest_normal}/initrd-iscsi-auto.service"
+    this="$(realpath "$0")"
+    cat >"${service}" <<EOF
+# generated by $this
+[Unit]
+Description=Poke iscsid to bring up iscsi devices
+
+DefaultDependencies=no
+Wants=iscsid.socket
+Wants=iscsiuio.socket
+Wants=network-online.target
+Before=initrd-root-device.target
+Conflicts=shutdown.target
+Before=shutdown.target
+After=network-online.target
+
+[Service]
+Type=oneshot
+ExecStart=$this --go
+EOF
+
+    mkdir -p "${dest_normal}/initrd-root-device.target.requires"
+    ln -s "../initrd-iscsi-auto.service" "${dest_normal}/initrd-root-device.target.requires/"
+}
+
+do_things() {
+    for spec in "${specs[@]}"; do
+        server=$(echo "$spec" | cut -d: -f2)
+        # protocol?
+        port=$(echo "$spec" | cut -d: -f4)
+        lun=$(echo "$spec" | cut -d: -f5)
+        target=$(echo "$spec" | cut -d: -f6-)
+
+        echo "$spec: will start server=$server port=$port lun=$lun target=$target"
+
+        iscsiadm -m discovery -t st -p "${server}${port:+:$port}"
+        iscsiadm -m node -T "$target" -l
+    done
+}
+
+if [ "${1:?}" == '--go' ]; then
+    do_things
+else
+    # invoked as generator
+    dest_normal=${1:?}
+
+    make_unit
+fi

mkosi.extra-iscsi/usr/lib/systemd/system/iscsi-shutdown.service.d/disable-in-initrd.conf

@@ -0,0 +1,10 @@
+# Make the unit do nothing in the initrd.
+# We can't mask the unit because iscsi.services has Requires=iscsi-shutdown.service,
+# so instead we let it survive switch-root.
+[Unit]
+IgnoreOnIsolate=true
+
+# This is a bug in the upstream unit file. This unit has DefaultDependencies=no,
+# and Conflicts=shutdown.target, but no ordering, which only guarantees that the
+# stop job will be queued.
+Before=shutdown.target