dracut/modules.d/98dracut-systemd/emergency.service

#  This file is part of dracut.
#
# See dracut.bootup(7) for details

[Unit]
Description=Emergency Shell
DefaultDependencies=no
After=systemd-vconsole-setup.service
Wants=systemd-vconsole-setup.service
Conflicts=shutdown.target
Before=shutdown.target

[Service]
Environment=HOME=/
Environment=DRACUT_SYSTEMD=1
Environment=NEWROOT=/sysroot
WorkingDirectory=/
ExecStart=/bin/dracut-emergency
ExecStopPost=-/usr/bin/systemctl --fail --no-block default
Type=idle
StandardInput=tty-force
StandardOutput=inherit
StandardError=inherit
KillMode=process
IgnoreSIGPIPE=no

# Bash ignores SIGTERM, so we send SIGHUP instead, to ensure that bash
# terminates cleanly.
KillSignal=SIGHUP
dracut-systemd/*.service: fix copyright message and comment 8 years ago			`# This file is part of dracut.`
systemd: changes for new initrd services Requires systemd >= 198 12 years ago			`#`
dracut-systemd/*.service: fix copyright message and comment 8 years ago			`# See dracut.bootup(7) for details`
systemd: changes for new initrd services Requires systemd >= 198 12 years ago
			`[Unit]`
			`Description=Emergency Shell`
			`DefaultDependencies=no`
			`After=systemd-vconsole-setup.service`
			`Wants=systemd-vconsole-setup.service`
dracut-systemd/*.service: conflict with shutdown target make reboot/poweroff/halt work also conflict with emergency.target 9 years ago			`Conflicts=shutdown.target`
			`Before=shutdown.target`
systemd: changes for new initrd services Requires systemd >= 198 12 years ago
			`[Service]`
			`Environment=HOME=/`
systemd: set environment vars DRACUT_SYSTEMD, NEWROOT in service file 12 years ago			`Environment=DRACUT_SYSTEMD=1`
			`Environment=NEWROOT=/sysroot`
systemd: changes for new initrd services Requires systemd >= 198 12 years ago			`WorkingDirectory=/`
			`ExecStart=/bin/dracut-emergency`
systemd: switch to new initrd.target (normal startup) : : v basic.target \| ______________________/\| / \| \| sysroot.mount \| \| \| v \| initrd-root-fs.target \| \| \| v \| initrd-parse-etc.service (custom initrd services) \| \| v \| (sysroot-usr.mount and \| various mounts marked \| with fstab option \| x-initrd.mount) \| \| \| v \| initrd-fs.target \| \| \______________________ \| \\| v initrd.target \| v initrd-cleanup.service isolates to initrd-switch-root.target \| v ______________________/\| / \| \| initrd-udevadm-cleanup-db.service \| \| (custom initrd services) \| \| \| \______________________ \| \\| v initrd-switch-root.target \| v initrd-switch-root.service \| v switch-root 12 years ago			`ExecStopPost=-/usr/bin/systemctl --fail --no-block default`
emergency.service: use Type=idle Type=oneshot, as currently set in dracut's emergency service file, causes an awkward situation if emergency mode is entered e.g. because of a root device timeout, and the root device appears later because it just has taken longer than the timeout. In that situation, my expectation (backed by past positive experience) is that the user should be able to simply exit the emergency shell and resume normal boot. :/# systemctl status sysroot.mount ● sysroot.mount - /sysroot Loaded: loaded (/proc/cmdline; bad; vendor preset: enabled) Active: active (mounted) since Mon 2017-10-09 14:32:15 CEST; 16s ago Where: /sysroot What: /dev/mapper/3600601600a30200024fbbaf3f500e411-part5 Docs: man:fstab(5) man:systemd-fstab-generator(8) Process: 1873 ExecMount=/usr/bin/mount /dev/disk/by-uuid/63751805-6abc-46a3-a66f-427920dece4d /sysroot -o ro (code=exited, status=0/SUCCESS) Tasks: 0 (limit: 512) :/# systemctl list-jobs JOB UNIT TYPE STATE 56 emergency.target start waiting 57 emergency.service start running 2 jobs listed. :/# exit logout Failed to start default.target: Transaction is destructive. (system keeps idling from this point on, user has no chance to do anything). This results from the combination of two effects: 1) initrd-root-fs.target sets "OnFailureJobMode=replace-irreversibly", 2) emergency.service's Type=oneshot causes the start jobs for both emergency.service and emergency.target to persist while the user is in the emergency shell. When the shell is exited, systemd tries to isolate "initrd.target" again, but this fails with "the transaction is destructive" error because of the still pending jobs. This patch fixes this by changing the Type of "emergency.service" from "oneshot" to "idle". 7 years ago			`Type=idle`
systemd: changes for new initrd services Requires systemd >= 198 12 years ago			`StandardInput=tty-force`
			`StandardOutput=inherit`
			`StandardError=inherit`
			`KillMode=process`
			`IgnoreSIGPIPE=no`

			`# Bash ignores SIGTERM, so we send SIGHUP instead, to ensure that bash`
			`# terminates cleanly.`
			`KillSignal=SIGHUP`