Commit 364340c8 authored by ssrq's avatar ssrq

[explorer/init] Refactor and testing

parent d895bb0e
......@@ -21,7 +21,7 @@
#
#
# Returns the name of the init system (PID 1)
#
# Expected values:
# Linux:
# Adélie Linux:
......@@ -35,122 +35,221 @@
# Debian:
# systemd, upstart, sysvinit, openrc, ???
# Devuan:
# sysvinit, ???
# sysvinit, sysvinit+openrc
# Gentoo:
# sysvinit+openrc, openrc-init, systemd
# OpenBMC:
# systemd
# OpenWrt:
# procd, init??
# procd, init???
# RedHat (RHEL, CentOS, Fedora, RedHat Linux, ...):
# systemd, upstart, sysvinit
# systemd, upstart, upstart-legacy, sysvinit
# Slackware:
# sysvinit
# SuSE:
# systemd, sysvinit
# Ubuntu:
# systemd, upstart, sysvinit
# systemd, upstart, upstart-legacy, sysvinit
# VoidLinux:
# runit
#
# GNU:
# Debian:
# hurd-init, sysvinit
# sysvinit, hurd-init
#
# BSD:
# {Free,Open,Net}BSD:
# init
#
# Mac OS X:
# launchd, init
# launchd, init+SystemStarter
#
# Solaris/Illumos:
# smf, init
# smf, init???
# NOTE: init systems can be stacked. This is popular to run OpenRC on top of
# sysvinit (Gentoo) or busybox-init (Alpine), but can also be used to run runit
# as a systemd service. This makes init system detection very complicated
# (which result is expected?) This script tries to untangle some combinations,
# OpenRC on top of sysv or busybox (X+openrc), but will ignore others (runit as
# a systemd service)
# NOTE: When we have no idea, nothing will be printed!
# NOTE:
# When trying to gather information about the init system make sure to do so
# without calling the binary! On some systems this triggers a reinitialisation
# of the system which we don't want (e.g. embedded systems).
# [root@fedora-12 ~]# readlink /proc/1/exe
# /sbin/init (deleted)
# [root@fedora-12 ~]# ls -l /proc/1/exe
# lrwxrwxrwx. 1 root root 0 2020-01-30 23:00 /proc/1/exe -> /sbin/init (deleted)
set -e
#set -x # DEBUG
validate_busybox_init() {
# It is quite common to use SysVinit to stack other init systemd
KERNEL_NAME=$(uname -s)
KNOWN_INIT_SYSTEMS=$(cat <<EOF
systemd
sysvinit
upstart
runit
procd
smf
launchd
init
hurd_init
systemstarter
EOF
)
common_candidates_by_kernel() {
case $KERNEL_NAME
in
FreeBSD|NetBSD|OpenBSD)
echo init
;;
Linux)
echo systemd
echo sysvinit
echo upstart
;;
GNU)
echo sysvinit
echo hurd-init
;;
Darwin)
echo launchd
echo systemstarter
;;
SunOS)
echo smf
;;
esac
}
## Helpers
trim() {
sed -e 's/^[[:blank:]]*//' -e 's/[[:blank:]]*$//' -e '/^[[:blank:]]*$/d'
}
unique() {
# Delete duplicate lines (keeping input order)
awk '!x[$0]++'
}
## Check functions
# These functions are used to verify if a guess is correct by checking some
# common property of a running system (presence of a directory in /run etc.)
check_busybox_init() (
busybox_path=${1:-/bin/busybox}
test -x "${busybox_path}" || return 1
grep -q 'BusyBox v[0-9]' "${busybox_path}" || return 1
# It is quite common to use Busybox init to stack other init systemd
# (like OpenRC) on top of it. So we check for that, too.
if stacked=$(validate_openrc)
if stacked=$(check_openrc)
then
echo "busybox-init+${stacked}"
else
echo busybox-init
fi
}
)
validate_hurd_init() {
# FIXME: Test me!
test -x /hurd/init || return 1
grep -q 'GNU Hurd' /hurd/init || return 1
check_hurd_init() (
init_exe=${1:-/hurd/init}
test -x "${init_exe}" || return 1
grep -q 'GNU Hurd' "${init_exe}" || return 1
echo hurd-init
)
check_init() {
# Checks for various BSD inits...
test -x /sbin/init || return 1
if grep -q -E '(Free|Net|Open)BSD' /sbin/init
then
echo init
return 0
fi
}
validate_openrc() {
check_launchd() {
command -v launchctl >/dev/null 2>&1 || return 1
launchctl getenv PATH >/dev/null || return 1
echo launchd
}
check_openrc() {
test -f /run/openrc/softlevel || return 1
echo openrc
}
validate_procd() {
grep -q 'procd' /sbin/procd || return 1
check_procd() (
procd_path=${1:-/sbin/procd}
test -x "${procd_path}" || return 1
grep -q 'procd' "${procd_path}" || return 1
echo procd
}
)
validate_runit() {
check_runit() {
test -d /run/runit || return 1
echo runit
}
validate_smf() {
check_smf() {
# XXX: Is this the correct way??
test -f /etc/svc/volatile/svc_nonpersist.db || return 1
echo smf
}
validate_systemd() {
check_systemd() {
# NOTE: sd_booted(3)
test -d /run/systemd/system/ || return 1
# systemctl --version | sed -e '/^systemd/!d;s/^systemd //'
echo systemd
}
validate_sysvinit() {
test -x /sbin/init \
&& grep -q 'INIT_VERSION=sysvinit-[0-9.]*' /sbin/init \
|| return 1
check_systemstarter() {
test -d /System/Library/StartupItems/ || return 1
test -f /System/Library/StartupItems/LoginWindow/StartupParameters.plist || return 1
echo init+SystemStarter
}
check_sysvinit() (
init_path=${1:-/sbin/init}
grep -q 'INIT_VERSION=sysvinit-[0-9.]*' "${init_path}" || return 1
# It is quite common to use SysVinit to stack other init systemd
# (like OpenRC) on top of it. So we check for that, too.
if stacked=$(validate_openrc)
if stacked=$(check_openrc)
then
echo "sysvinit+${stacked}"
else
echo sysvinit
fi
unset stacked
}
)
validate_upstart() {
check_upstart() {
test -x "$(command -v initctl)" || return 1
case $(initctl version)
in
*'(upstart '*')')
# if type -d /etc/init
# then
# # modern (DBus-based?) upstart >= 0.5
# :
# elif type -d /etc/events.d
# then
# # ancient upstart
# :
# fi
echo upstart
if test -d /etc/init
then
# modern (DBus-based?) upstart >= 0.5
echo upstart
elif test -d /etc/event.d
then
# ancient upstart
echo upstart-legacy
else
# whatever...
echo upstart
fi
;;
*)
return 1
......@@ -163,7 +262,7 @@ find_init_procfs() (
test -h /proc/1/exe || return 1
# Find init executable
init_exe=$(ls -l /proc/1/exe 2>/dev/null)
init_exe=$(ls -l /proc/1/exe 2>/dev/null) || return 1
init_exe=${init_exe#* -> }
if ! test -x "$init_exe"
......@@ -171,21 +270,100 @@ find_init_procfs() (
# On some rare occasions it can happen that the
# running init's binary has been replaced. In this
# case Linux adjusts the symlink to "X (deleted)"
case $init_exe
in
*' (deleted)')
init_exe=${init_exe% (deleted)}
test -x "$init_exe" || exit 1
;;
*)
exit 1
;;
esac
# [root@fedora-12 ~]# readlink /proc/1/exe
# /sbin/init (deleted)
# [root@fedora-12 ~]# ls -l /proc/1/exe
# lrwxrwxrwx. 1 root root 0 2020-01-30 23:00 /proc/1/exe -> /sbin/init (deleted)
init_exe=${init_exe% (deleted)}
test -x "$init_exe" || return 1
fi
echo "${init_exe}"
)
guess_by_path() {
case $1
in
/bin/busybox)
check_busybox_init "$1" && return
;;
/lib/systemd/systemd)
check_systemd "$1" && return
;;
/hurd/init)
check_hurd_init "$1" && return
;;
/sbin/launchd)
check_launchd "$1" && return
;;
/usr/bin/runit|/sbin/runit)
check_runit "$1" && return
;;
/sbin/openrc-init)
if check_openrc "$1" >/dev/null
then
echo openrc-init
return
fi
;;
/sbin/procd)
check_procd && return
;;
/sbin/init|*/init)
# init: it could be anything -> (explicit) no match
return 1
;;
esac
# No match
return 1
}
guess_by_comm_name() {
case $1
in
busybox)
check_busybox_init && return
;;
openrc-init)
if check_openrc >/dev/null
then
echo openrc-init
return 0
fi
;;
init)
# init could be anything -> no match
return 1
;;
*)
# Run check function by comm name if available.
# Fall back to comm name if either it does not exist or
# returns non-zero.
if type "check_$1" >/dev/null
then
"check_$1" && return
else
echo "$1" ; return 0
fi
esac
return 1
}
check_list() (
# List must be a multi-line input on stdin (one name per line)
while read init
do
"check_${init}" || continue
return 0
done
return 1
)
# BusyBox's versions of ps and pgrep do not support some options
# depending on which compile-time options have been used.
......@@ -194,25 +372,31 @@ find_init_pgrep() {
}
find_init_ps() {
case $(uname -s)
case $KERNEL_NAME
in
Darwin|NetBSD)
ps -o ucomm= -p 1 2>/dev/null
Darwin)
ps -o command -p 1 2>/dev/null | tail -n +2
;;
FreeBSD)
ps -o command= -p 1 2>/dev/null | cut -d ' ' -f 1
ps -o args= -p 1 2>/dev/null | cut -d ' ' -f 1
;;
Linux)
ps -o comm= -p 1 2>/dev/null
;;
NetBSD)
ps -o comm= -p 1 2>/dev/null
;;
OpenBSD)
ps -o command -p 1 2>/dev/null | tail -n +2 | cut -d ' ' -f 1
ps -o args -p 1 2>/dev/null | tail -n +2 | cut -d ' ' -f 1
;;
*)
ps -o comm= -p 1 2>/dev/null
ps -o args= -p 1 2>/dev/null
;;
esac
esac | trim # trim trailing whitespace (some ps like Darwin add it)
}
find_init() {
case $(uname -s)
case $KERNEL_NAME
in
Linux|GNU|NetBSD)
find_init_procfs || find_init_pgrep || find_init_ps
......@@ -233,65 +417,23 @@ find_init() {
esac
}
validate_by_comm_name() {
case $1
in
busybox)
validate_busybox_init
;;
init)
# FIXME: Do some more magic here!
echo init
;;
openrc-init)
validate_openrc >/dev/null && echo openrc-init
;;
runit)
validate_runit
;;
systemd)
validate_systemd
;;
*)
# Run validate function by comm name if available.
# Fall back to comm name if either it does not exist or
# returns non-zero.
type "validate_$1" >/dev/null && "validate_$1" || echo $1
esac
}
try_all() {
# init: it could be anything...
# We try some approaches to gather more information about init without
# calling it! On some init systemd this triggers a reinitialisation of
# the system which we don't want (e.g. embedded systems).
validate_sysvinit || \
validate_openrc || \
validate_runit || \
validate_smf || \
validate_upstart || \
validate_hurd_init || \
echo init # fallback
}
# -----
init=$(find_init)
if test -x "${init}"
then
case $init
in
/hurd/init)
# FIXME: Create validate function
echo hurd-init
;;
*/init)
try_all
;;
*)
validate_by_comm_name "$(basename "${init}")"
;;
esac
else
validate_by_comm_name "${init}"
fi
# If we got a path, guess by the path first (fall back to file name if no match)
# else guess by file name directly.
{
test -x "${init}" \
&& guess_by_path "${init}" \
|| guess_by_comm_name "$(basename "${init}")"
} && exit 0 || true
# Guessing based on the file path and name didn’t lead to a definitive result.
#
# We go through all of the checks until we find a match. To speed up the
# process, common cases will be checked first based on the underlying kernel.
{ common_candidates_by_kernel; echo "${KNOWN_INIT_SYSTEMS}"; } \
| unique | check_list
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