[systemd-devel] [PATCH 2/2] initrd: add unit files needed for basic systemd-in-initrd support

[Tom Gundersen]

This will:
 * mount all configured filesystems (typically the rootfs on /sysroot)
 * reload the configuration to pick up anything from the mounted fs (typically
   /sysroot/etc/fstab.sys)
 * mount any newly configured filesystems (typically /usr on /sysroot/usr, if
   applicable)
 * shut-down and clean-up any daemons running in the initramfs (typically udevd)
 * switch-root to /sysroot and start the real init

Cc: Harald Hoyer <harald.hoyer at gmail.com>
Cc: Dave Reisner <d at falconindy.com>
---
 Makefile.am                             |  7 ++++++-
 units/initrd-cleanup.service            | 18 ++++++++++++++++++
 units/initrd-parse-etc.service          | 19 +++++++++++++++++++
 units/initrd-switch-root.service        | 19 +++++++++++++++++++
 units/initrd-switch-root.target         | 16 ++++++++++++++++
 units/initrd-udevadm-cleanup-db.service | 18 ++++++++++++++++++
 6 files changed, 96 insertions(+), 1 deletion(-)
 create mode 100644 units/initrd-cleanup.service
 create mode 100644 units/initrd-parse-etc.service
 create mode 100644 units/initrd-switch-root.service
 create mode 100644 units/initrd-switch-root.target
 create mode 100644 units/initrd-udevadm-cleanup-db.service

diff --git a/Makefile.am b/Makefile.am
index f0f0ebc..aa2164c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -373,7 +373,12 @@ dist_systemunit_DATA = \
 	units/systemd-ask-password-console.path \
 	units/systemd-udevd-control.socket \
 	units/systemd-udevd-kernel.socket \
-	units/system-update.target
+	units/system-update.target \
+	units/initrd-parse-etc.service \
+	units/initrd-cleanup.service \
+	units/initrd-switch-root.target \
+	units/initrd-udevadm-cleanup-db.service \
+	units/initrd-switch-root.service
 
 nodist_systemunit_DATA = \
 	units/getty at .service \
diff --git a/units/initrd-cleanup.service b/units/initrd-cleanup.service
new file mode 100644
index 0000000..8998696
--- /dev/null
+++ b/units/initrd-cleanup.service
@@ -0,0 +1,18 @@
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+[Unit]
+Description=Cleaning Up and Shutting Down Daemons
+DefaultDependencies=no
+ConditionPathExists=/etc/initrd-release
+OnFailure=emergency.target
+Requires=local-fs.target swap.target
+After=local-fs.target swap.target
+
+[Service]
+Type=oneshot
+ExecStart=/usr/bin/systemctl --no-block isolate initrd-switch-root.target
diff --git a/units/initrd-parse-etc.service b/units/initrd-parse-etc.service
new file mode 100644
index 0000000..4bfbb0f
--- /dev/null
+++ b/units/initrd-parse-etc.service
@@ -0,0 +1,19 @@
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+[Unit]
+Description=Reload Configuration from the Real Root
+DefaultDependencies=no
+Requires=local-fs.target swap.target
+After=local-fs.target swap.target
+OnFailure=emergency.target
+ConditionPathExists=/etc/initrd-release
+
+[Service]
+Type=oneshot
+ExecStartPre=/usr/bin/systemctl daemon-reload
+ExecStart=/usr/bin/systemctl --no-block start initrd-cleanup.service
diff --git a/units/initrd-switch-root.service b/units/initrd-switch-root.service
new file mode 100644
index 0000000..e076b39
--- /dev/null
+++ b/units/initrd-switch-root.service
@@ -0,0 +1,19 @@
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+[Unit]
+Description=Switch Root
+DefaultDependencies=no
+ConditionPathExists=/etc/initrd-release
+OnFailure=emergency.target
+AllowIsolate=yes
+
+[Service]
+Type=oneshot
+# we have to use "--force" here, otherwise systemd would umount /run
+ExecStart=/usr/bin/systemctl --no-block --force switch-root /sysroot
+KillMode=none
diff --git a/units/initrd-switch-root.target b/units/initrd-switch-root.target
new file mode 100644
index 0000000..f706d29
--- /dev/null
+++ b/units/initrd-switch-root.target
@@ -0,0 +1,16 @@
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+[Unit]
+Description=Switch Root
+ConditionPathExists=/etc/initrd-release
+DefaultDependencies=no
+Requires=initrd-switch-root.service
+Before=initrd-switch-root.service
+AllowIsolate=yes
+Wants=initrd-udevadm-cleanup-db.service local-fs.target swap.target systemd-journald.service
+After=initrd-udevadm-cleanup-db.service local-fs.target swap.target emergency.service emergency.target
diff --git a/units/initrd-udevadm-cleanup-db.service b/units/initrd-udevadm-cleanup-db.service
new file mode 100644
index 0000000..983189e
--- /dev/null
+++ b/units/initrd-udevadm-cleanup-db.service
@@ -0,0 +1,18 @@
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+[Unit]
+Description=Cleanup udevd DB
+DefaultDependencies=no
+ConditionPathExists=/etc/initrd-release
+Conflicts=systemd-udevd.service systemd-udevd-control.socket systemd-udevd-kernel.socket
+After=systemd-udevd.service systemd-udevd-control.socket systemd-udevd-kernel.socket
+Before=initrd-switch-root.target
+
+[Service]
+Type=oneshot
+ExecStart=-/usr/bin/udevadm info --cleanup-db
-- 
1.8.1.4