freebsd-skq/share/examples/jails/jib
avg e96b4170d0 add ability to set watchdog timeout for a shutdown
This change allows to specify a watchdog(9) timeout for a system
shutdown.  The timeout is activated when the watchdogd daemon is
stopped.  The idea is to a prevent any indefinite hang during late
stages of the shutdown.  The feature is implemented in rc.d/watchdogd,
it builds upon watchdogd -x option.

Note that the shutdown timeout is not actiavted when the watchdogd
service is individually stopped by an operator.  It is also not
activated for the 'shutdown' to the single-user mode.  In those cases it
is assumed that the operator knows what they are doing and they have
means to recover the system should it hang.

Significant subchanges and implementation details:
- the argument to rc.shutdown, completely unused before, is assigned to
  rc_shutdown variable that can be inspected by rc scripts
- init(8) passes "single" or "reboot" as the argument, this is not
  changed
- the argument is not mandatory and if it is not set then rc_shutdown is
  set to "unspecified"
- however, the default jail management scripts and jail configuration
  examples have been updated to pass "jail" to rc.shutdown, just in case
- the new timeout can be set via watchdogd_shutdown_timeout rc option
- for consistency, the regular timeout can now be set via
  watchdogd_timeout rc option
- watchdogd_shutdown_timeout and watchdogd_timeout override timeout
  specifications in watchdogd_flags
- existing configurations, where the new rc options are not set, should
  keep working as before

I am not particularly wed to any of the implementation specifics.
I am open to changing or removing any of them as long as the provided
functionality is the same (or very close) to the proposed one.
For example, I think it can be implemented without using watchdogd -x,
by means of watchdog(1) alone.  In that case there would be a small
window between stopping watchdogd and running watchdog, but I think that
that is acceptable.

Reviewed by:	bcr (man page changes)
MFC after:	5 weeks
Relnotes:	yes
Differential Revision: https://reviews.freebsd.org/D21221
2019-10-03 11:23:10 +00:00

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#!/bin/sh
#-
# Copyright (c) 2016 Devin Teske
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $FreeBSD$
#
############################################################ IDENT(1)
#
# $Title: if_bridge(4) management script for vnet jails $
#
############################################################ INFORMATION
#
# Use this tool with jail.conf(5) (or rc.conf(5) ``legacy'' configuration) to
# manage `vnet' interfaces for jails. Designed to automate the creation of vnet
# interface(s) during jail `prestart' and destroy said interface(s) during jail
# `poststop'.
#
# In jail.conf(5) format:
#
# ### BEGIN EXCERPT ###
#
# xxx {
# host.hostname = "xxx.yyy";
# path = "/vm/xxx";
#
# #
# # NB: Below 2-lines required
# # NB: The number of eNb_xxx interfaces should match the number of
# # arguments given to `jib addm xxx' in exec.prestart value.
# #
# vnet;
# vnet.interface = e0b_xxx, e1b_xxx, ...;
#
# exec.clean;
# exec.system_user = "root";
# exec.jail_user = "root";
#
# #
# # NB: Below 2-lines required
# # NB: The number of arguments after `jib addm xxx' should match
# # the number of eNb_xxx arguments in vnet.interface value.
# #
# exec.prestart += "jib addm xxx em0 em1 ...";
# exec.poststop += "jib destroy xxx";
#
# # Standard recipe
# exec.start += "/bin/sh /etc/rc";
# exec.stop = "/bin/sh /etc/rc.shutdown jail";
# exec.consolelog = "/var/log/jail_xxx_console.log";
# mount.devfs;
#
# # Optional (default off)
# #allow.mount;
# #allow.set_hostname = 1;
# #allow.sysvipc = 1;
# #devfs_ruleset = "11"; # rule to unhide bpf for DHCP
# }
#
# ### END EXCERPT ###
#
# In rc.conf(5) ``legacy'' format (used when /etc/jail.conf does not exist):
#
# ### BEGIN EXCERPT ###
#
# jail_enable="YES"
# jail_list="xxx"
#
# #
# # Global presets for all jails
# #
# jail_devfs_enable="YES" # mount devfs
#
# #
# # Global options (default off)
# #
# #jail_mount_enable="YES" # mount /etc/fstab.{name}
# #jail_set_hostname_allow="YES" # Allow hostname to change
# #jail_sysvipc_allow="YES" # Allow SysV Interprocess Comm.
#
# # xxx
# jail_xxx_hostname="xxx.shxd.cx" # hostname
# jail_xxx_rootdir="/vm/xxx" # root directory
# jail_xxx_vnet_interfaces="e0b_xxx e1bxxx ..." # vnet interface(s)
# jail_xxx_exec_prestart0="jib addm xxx em0 em1 ..." # bridge interface(s)
# jail_xxx_exec_poststop0="jib destroy xxx" # destroy interface(s)
# #jail_xxx_mount_enable="YES" # mount /etc/fstab.xxx
# #jail_xxx_devfs_ruleset="11" # rule to unhide bpf for DHCP
#
# ### END EXCERPT ###
#
# Note that the legacy rc.conf(5) format is converted to
# /var/run/jail.{name}.conf by /etc/rc.d/jail if jail.conf(5) is missing.
#
# ASIDE: dhclient(8) inside a vnet jail...
#
# To allow dhclient(8) to work inside a vnet jail, make sure the following
# appears in /etc/devfs.rules (which should be created if it doesn't exist):
#
# [devfsrules_jail=11]
# add include $devfsrules_hide_all
# add include $devfsrules_unhide_basic
# add include $devfsrules_unhide_login
# add path 'bpf*' unhide
#
# And set ether devfs.ruleset="11" (jail.conf(5)) or
# jail_{name}_devfs_ruleset="11" (rc.conf(5)).
#
# NB: While this tool can't create every type of desirable topology, it should
# handle most setups, minus some which considered exotic or purpose-built.
#
############################################################ GLOBALS
pgm="${0##*/}" # Program basename
#
# Global exit status
#
SUCCESS=0
FAILURE=1
############################################################ FUNCTIONS
usage()
{
local action usage descr
exec >&2
echo "Usage: $pgm action [arguments]"
echo "Actions:"
for action in \
addm \
show \
show1 \
destroy \
; do
eval usage=\"\$jib_${action}_usage\"
[ "$usage" ] || continue
eval descr=\"\$jib_${action}_descr\"
printf "\t%s\n\t\t%s\n" "$usage" "$descr"
done
exit $FAILURE
}
action_usage()
{
local usage descr action="$1"
eval usage=\"\$jib_${action}_usage\"
echo "Usage: $pgm $usage" >&2
eval descr=\"\$jib_${action}_descr\"
printf "\t%s\n" "$descr"
exit $FAILURE
}
derive_mac()
{
local OPTIND=1 OPTARG __flag
local __mac_num= __make_pair=
while getopts 2n: __flag; do
case "$__flag" in
2) __make_pair=1 ;;
n) __mac_num=${OPTARG%%[^0-9]*} ;;
esac
done
shift $(( $OPTIND - 1 ))
if [ ! "$__mac_num" ]; then
eval __mac_num=\${_${iface}_num:--1}
__mac_num=$(( $__mac_num + 1 ))
eval _${iface}_num=\$__mac_num
fi
local __iface="$1" __name="$2" __var_to_set="$3" __var_to_set_b="$4"
local __iface_devid __new_devid __num __new_devid_b
#
# Calculate MAC address derived from given iface.
#
# The formula I'm using is ``NP:SS:SS:II:II:II'' where:
# + N denotes 4 bits used as a counter to support branching
# each parent interface up to 15 times under the same jail
# name (see S below).
# + P denotes the special nibble whose value, if one of
# 2, 6, A, or E (but usually 2) denotes a privately
# administered MAC address (while remaining routable).
# + S denotes 16 bits, the sum(1) value of the jail name.
# + I denotes bits that are inherited from parent interface.
#
# The S bits are a CRC-16 checksum of NAME, allowing the jail
# to change link numbers in ng_bridge(4) without affecting the
# MAC address. Meanwhile, if...
# + the jail NAME changes (e.g., it was duplicated and given
# a new name with no other changes)
# + the underlying network interface changes
# + the jail is moved to another host
# the MAC address will be recalculated to a new, similarly
# unique value preventing conflict.
#
__iface_devid=$( ifconfig $__iface ether | awk '/ether/,$0=$2' )
# ??:??:??:II:II:II
__new_devid=${__iface_devid#??:??:??} # => :II:II:II
# => :SS:SS:II:II:II
__num=$( set -- `echo -n "$__name" | sum` && echo $1 )
__new_devid=$( printf :%02x:%02x \
$(( $__num >> 8 & 255 )) $(( $__num & 255 )) )$__new_devid
# => P:SS:SS:II:II:II
case "$__iface_devid" in
?2:*) __new_devid=a$__new_devid __new_devid_b=e$__new_devid ;;
?[Ee]:*) __new_devid=2$__new_devid __new_devid_b=6$__new_devid ;;
*) __new_devid=2$__new_devid __new_devid_b=e$__new_devid
esac
# => NP:SS:SS:II:II:II
__new_devid=$( printf %x $(( $__mac_num & 15 )) )$__new_devid
__new_devid_b=$( printf %x $(( $__mac_num & 15 )) )$__new_devid_b
#
# Return derivative MAC address(es)
#
if [ "$__make_pair" ]; then
if [ "$__var_to_set" -a "$__var_to_set_b" ]; then
eval $__var_to_set=\$__new_devid
eval $__var_to_set_b=\$__new_devid_b
else
echo $__new_devid $__new_devid_b
fi
else
if [ "$__var_to_set" ]; then
eval $__var_to_set=\$__new_devid
else
echo $__new_devid
fi
fi
}
mustberoot_to_continue()
{
if [ "$( id -u )" -ne 0 ]; then
echo "Must run as root!" >&2
exit $FAILURE
fi
}
jib_addm_usage="addm [-b BRIDGE_NAME] NAME [!]iface0 [[!]iface1 ...]"
jib_addm_descr="Creates e0b_NAME [e1b_NAME ...]"
jib_addm()
{
local OPTIND=1 OPTARG flag bridge=bridge
while getopts b: flag; do
case "$flag" in
b) bridge="${OPTARG:-bridge}" ;;
*) action_usage addm # NOTREACHED
esac
done
shift $(( $OPTIND - 1 ))
local name="$1"
[ "${name:-x}" = "${name#*[!0-9a-zA-Z_]}" -a $# -gt 1 ] ||
action_usage addm # NOTREACHED
shift 1 # name
mustberoot_to_continue
local iface eiface_devid_a eiface_devid_b
local new no_derive num quad i=0
for iface in $*; do
no_derive=
case "$iface" in
!*) iface=${iface#!} no_derive=1 ;;
esac
# Make sure the interface doesn't exist already
if ifconfig "e${i}a_$name" > /dev/null 2>&1; then
i=$(( $i + 1 ))
continue
fi
# Bring the interface up
ifconfig $iface up || return
# Make sure the interface has been bridged
if ! ifconfig "$iface$bridge" > /dev/null 2>&1; then
new=$( ifconfig bridge create ) || return
ifconfig $new addm $iface || return
ifconfig $new name "$iface$bridge" || return
ifconfig "$iface$bridge" up || return
fi
# Create a new interface to the bridge
new=$( ifconfig epair create ) || return
ifconfig "$iface$bridge" addm $new || return
# Rename the new interface
ifconfig $new name "e${i}a_$name" || return
ifconfig ${new%a}b name "e${i}b_$name" || return
ifconfig "e${i}a_$name" up || return
ifconfig "e${i}b_$name" up || return
#
# Set the MAC address of the new interface using a sensible
# algorithm to prevent conflicts on the network.
#
eiface_devid_a= eiface_devid_b=
[ "$no_derive" ] || derive_mac -2 $iface "$name" \
eiface_devid_a eiface_devid_b
if [ "$eiface_devid_a" -a "$eiface_devid_b" ]; then
ifconfig "e${i}a_$name" ether $eiface_devid_a
ifconfig "e${i}b_$name" ether $eiface_devid_b
fi > /dev/null 2>&1
i=$(( $i + 1 ))
done # for iface
}
jib_show_usage="show"
jib_show_descr="List possible NAME values for \`show NAME'"
jib_show1_usage="show NAME"
jib_show1_descr="Lists e0b_NAME [e1b_NAME ...]"
jib_show2_usage="show [NAME]"
jib_show()
{
local OPTIND=1 OPTARG flag
while getopts "" flag; do
case "$flag" in
*) action_usage show2 # NOTREACHED
esac
done
shift $(( $OPTIND - 1 ))
if [ $# -eq 0 ]; then
ifconfig | awk '
/^[^:[:space:]]+:/ {
iface = $1
sub(/:.*/, "", iface)
next
}
$1 == "groups:" {
for (n = split($0, group); n > 1; n--) {
if (group[n] != "bridge") continue
print iface
next
}
}' |
xargs -rn1 ifconfig |
awk '$1 == "member:" &&
sub(/^e[[:digit:]]+a_/, "", $2), $0 = $2' |
sort -u
return
fi
ifconfig | awk -v name="$1" '
match($0, /^e[[:digit:]]+a_/) && sub(/:.*/, "") &&
substr($1, RSTART + RLENGTH) == name
' | sort
}
jib_destroy_usage="destroy NAME"
jib_destroy_descr="Destroy e0b_NAME [e1b_NAME ...]"
jib_destroy()
{
local OPTIND=1 OPTARG flag
while getopts "" flag; do
case "$flag" in
*) action_usage destroy # NOTREACHED
esac
done
shift $(( $OPTIND -1 ))
local name="$1"
[ "${name:-x}" = "${name#*[!0-9a-zA-Z_]}" -a $# -eq 1 ] ||
action_usage destroy # NOTREACHED
mustberoot_to_continue
jib_show "$name" | xargs -rn1 -I eiface ifconfig eiface destroy
}
############################################################ MAIN
#
# Command-line arguments
#
action="$1"
[ "$action" ] || usage # NOTREACHED
#
# Validate action argument
#
if [ "$BASH_VERSION" ]; then
type="$( type -t "jib_$action" )" || usage # NOTREACHED
else
type="$( type "jib_$action" 2> /dev/null )" || usage # NOTREACHED
fi
case "$type" in
*function)
shift 1 # action
eval "jib_$action" \"\$@\"
;;
*) usage # NOTREACHED
esac
################################################################################
# END
################################################################################