441 lines
9 KiB
Bash
Executable file
441 lines
9 KiB
Bash
Executable file
#!/bin/sh -e
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#
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# 2016 Daniel Heule (hda at sfs.biz)
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# Copyright 2017, Philippe Gregoire <pg@pgregoire.xyz>
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# 2020 Dennis Camera (dennis.camera at ssrq-sds-fds.ch)
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#
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# This file is part of cdist.
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#
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# cdist is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# cdist is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with cdist. If not, see <http://www.gnu.org/licenses/>.
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#
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#
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# Returns the name of the init system (PID 1)
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# Expected values:
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# Linux:
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# Adélie Linux:
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# sysvinit+openrc
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# Alpine Linux:
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# busybox-init+openrc
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# ArchLinux:
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# systemd, sysvinit
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# CRUX:
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# sysvinit
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# Debian:
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# systemd, upstart, sysvinit, openrc, ???
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# Devuan:
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# sysvinit, sysvinit+openrc
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# Gentoo:
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# sysvinit+openrc, openrc-init, systemd
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# OpenBMC:
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# systemd
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# OpenWrt:
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# procd, init???
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# RedHat (RHEL, CentOS, Fedora, RedHat Linux, ...):
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# systemd, upstart, upstart-legacy, sysvinit
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# Slackware:
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# sysvinit
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# SuSE:
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# systemd, sysvinit
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# Ubuntu:
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# systemd, upstart, upstart-legacy, sysvinit
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# VoidLinux:
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# runit
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#
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# GNU:
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# Debian:
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# sysvinit, hurd-init
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#
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# BSD:
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# {Free,Open,Net}BSD:
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# init
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#
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# Mac OS X:
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# launchd, init+SystemStarter
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#
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# Solaris/Illumos:
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# smf, init???
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# NOTE: init systems can be stacked. This is popular to run OpenRC on top of
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# sysvinit (Gentoo) or busybox-init (Alpine), but can also be used to run runit
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# as a systemd service. This makes init system detection very complicated
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# (which result is expected?) This script tries to untangle some combinations,
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# OpenRC on top of sysv or busybox (X+openrc), but will ignore others (runit as
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# a systemd service)
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# NOTE: When we have no idea, nothing will be printed!
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# NOTE:
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# When trying to gather information about the init system make sure to do so
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# without calling the binary! On some systems this triggers a reinitialisation
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# of the system which we don't want (e.g. embedded systems).
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set -e
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KERNEL_NAME=$(uname -s)
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KNOWN_INIT_SYSTEMS=$(cat <<EOF
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systemd
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sysvinit
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upstart
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runit
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procd
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smf
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launchd
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init
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hurd_init
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systemstarter
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EOF
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)
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common_candidates_by_kernel() {
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case $KERNEL_NAME
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in
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FreeBSD|NetBSD|OpenBSD)
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echo init
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;;
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Linux)
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echo systemd
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echo sysvinit
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echo upstart
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;;
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GNU)
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echo sysvinit
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echo hurd-init
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;;
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Darwin)
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echo launchd
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echo systemstarter
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;;
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SunOS)
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echo smf
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;;
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esac
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}
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## Helpers
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trim() {
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sed -e 's/^[[:blank:]]*//' -e 's/[[:blank:]]*$//' -e '/^[[:blank:]]*$/d'
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}
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unique() {
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# Delete duplicate lines (keeping input order)
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# NOTE: Solaris AWK breaks without if/print construct.
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awk '{ if (!x[$0]++) print }'
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}
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## Check functions
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# These functions are used to verify if a guess is correct by checking some
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# common property of a running system (presence of a directory in /run etc.)
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check_busybox_init() (
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busybox_path=${1:-/bin/busybox}
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test -x "${busybox_path}" || return 1
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grep -q 'BusyBox v[0-9]' "${busybox_path}" || return 1
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# It is quite common to use Busybox init to stack other init systemd
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# (like OpenRC) on top of it. So we check for that, too.
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if stacked=$(check_openrc)
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then
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echo "busybox-init+${stacked}"
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else
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echo busybox-init
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fi
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)
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check_hurd_init() (
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init_exe=${1:-/hurd/init}
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test -x "${init_exe}" || return 1
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grep -q 'GNU Hurd' "${init_exe}" || return 1
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echo hurd-init
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)
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check_init() {
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# Checks for various BSD inits...
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test -x /sbin/init || return 1
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if grep -q -E '(Free|Net|Open)BSD' /sbin/init
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then
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echo init
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return 0
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fi
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}
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check_launchd() {
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command -v launchctl >/dev/null 2>&1 || return 1
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launchctl getenv PATH >/dev/null || return 1
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echo launchd
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}
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check_openrc() {
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test -f /run/openrc/softlevel || return 1
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echo openrc
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}
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check_procd() (
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procd_path=${1:-/sbin/procd}
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test -x "${procd_path}" || return 1
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grep -q 'procd' "${procd_path}" || return 1
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echo procd
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)
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check_runit() {
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test -d /run/runit || return 1
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echo runit
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}
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check_smf() {
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# XXX: Is this the correct way??
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test -f /etc/svc/volatile/svc_nonpersist.db || return 1
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echo smf
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}
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check_systemd() {
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# NOTE: sd_booted(3)
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test -d /run/systemd/system/ || return 1
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# systemctl --version | sed -e '/^systemd/!d;s/^systemd //'
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echo systemd
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}
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check_systemstarter() {
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test -d /System/Library/StartupItems/ || return 1
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test -f /System/Library/StartupItems/LoginWindow/StartupParameters.plist || return 1
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echo init+SystemStarter
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}
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check_sysvinit() (
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init_path=${1:-/sbin/init}
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grep -q 'INIT_VERSION=sysvinit-[0-9.]*' "${init_path}" || return 1
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# It is quite common to use SysVinit to stack other init systemd
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# (like OpenRC) on top of it. So we check for that, too.
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if stacked=$(check_openrc)
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then
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echo "sysvinit+${stacked}"
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else
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echo sysvinit
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fi
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unset stacked
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)
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check_upstart() {
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test -x "$(command -v initctl)" || return 1
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case $(initctl version)
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in
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*'(upstart '*')')
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if test -d /etc/init
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then
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# modern (DBus-based?) upstart >= 0.5
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echo upstart
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elif test -d /etc/event.d
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then
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# ancient upstart
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echo upstart-legacy
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else
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# whatever...
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echo upstart
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fi
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;;
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*)
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return 1
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;;
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esac
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}
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find_init_procfs() (
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# First, check if the required file in procfs exists...
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test -h /proc/1/exe || return 1
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# Find init executable
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init_exe=$(ls -l /proc/1/exe 2>/dev/null) || return 1
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init_exe=${init_exe#* -> }
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if ! test -x "$init_exe"
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then
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# On some rare occasions it can happen that the
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# running init's binary has been replaced. In this
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# case Linux adjusts the symlink to "X (deleted)"
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# [root@fedora-12 ~]# readlink /proc/1/exe
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# /sbin/init (deleted)
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# [root@fedora-12 ~]# ls -l /proc/1/exe
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# lrwxrwxrwx. 1 root root 0 2020-01-30 23:00 /proc/1/exe -> /sbin/init (deleted)
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init_exe=${init_exe% (deleted)}
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test -x "$init_exe" || return 1
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fi
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echo "${init_exe}"
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)
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guess_by_path() {
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case $1
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in
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/bin/busybox)
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check_busybox_init "$1" && return
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;;
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/lib/systemd/systemd)
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check_systemd "$1" && return
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;;
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/hurd/init)
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check_hurd_init "$1" && return
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;;
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/sbin/launchd)
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check_launchd "$1" && return
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;;
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/usr/bin/runit|/sbin/runit)
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check_runit "$1" && return
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;;
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/sbin/openrc-init)
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if check_openrc "$1" >/dev/null
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then
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echo openrc-init
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return
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fi
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;;
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/sbin/procd)
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check_procd "$1" && return
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;;
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/sbin/init|*/init)
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# init: it could be anything -> (explicit) no match
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return 1
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;;
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esac
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# No match
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return 1
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}
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guess_by_comm_name() {
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case $1
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in
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busybox)
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check_busybox_init && return
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;;
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openrc-init)
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if check_openrc >/dev/null
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then
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echo openrc-init
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return 0
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fi
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;;
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init)
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# init could be anything -> no match
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return 1
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;;
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*)
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# Run check function by comm name if available.
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# Fall back to comm name if either it does not exist or
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# returns non-zero.
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if type "check_$1" >/dev/null
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then
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"check_$1" && return
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else
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echo "$1" ; return 0
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fi
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esac
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return 1
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}
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check_list() (
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# List must be a multi-line input on stdin (one name per line)
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while read -r init
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do
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"check_${init}" || continue
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return 0
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done
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return 1
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)
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# BusyBox's versions of ps and pgrep do not support some options
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# depending on which compile-time options have been used.
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find_init_pgrep() {
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pgrep -P0 -fl 2>/dev/null | awk -F '[[:blank:]]' '$1 == 1 { print $2 }'
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}
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find_init_ps() {
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case $KERNEL_NAME
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in
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Darwin)
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ps -o command -p 1 2>/dev/null | tail -n +2
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;;
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FreeBSD)
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ps -o args= -p 1 2>/dev/null | cut -d ' ' -f 1
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;;
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Linux)
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ps -o comm= -p 1 2>/dev/null
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;;
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NetBSD)
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ps -o comm= -p 1 2>/dev/null
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;;
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OpenBSD)
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ps -o args -p 1 2>/dev/null | tail -n +2 | cut -d ' ' -f 1
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;;
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*)
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ps -o args= -p 1 2>/dev/null
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;;
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esac | trim # trim trailing whitespace (some ps like Darwin add it)
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}
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find_init() {
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case $KERNEL_NAME
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in
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Linux|GNU|NetBSD)
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find_init_procfs || find_init_pgrep || find_init_ps
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;;
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FreeBSD)
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find_init_procfs || find_init_ps
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;;
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OpenBSD)
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find_init_pgrep || find_init_ps
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;;
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Darwin|SunOS)
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find_init_ps
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;;
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*)
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echo "Don't know how to determine init." >&2
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echo 'Please send a patch.' >&2
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exit 1
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esac
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}
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# -----
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init=$(find_init)
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# If we got a path, guess by the path first (fall back to file name if no match)
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# else guess by file name directly.
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# shellcheck disable=SC2015
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{
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test -x "${init}" \
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&& guess_by_path "${init}" \
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|| guess_by_comm_name "$(basename "${init}")"
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} && exit 0 || true
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# Guessing based on the file path and name didn’t lead to a definitive result.
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#
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# We go through all of the checks until we find a match. To speed up the
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# process, common cases will be checked first based on the underlying kernel.
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{ common_candidates_by_kernel; echo "${KNOWN_INIT_SYSTEMS}"; } \
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| unique | check_list
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