Date: Thu, 27 Aug 2015 14:21:39 -0700 From: Devin Teske <dteske@FreeBSD.org> To: Allan Jude <allanjude@freebsd.org> Cc: freebsd-hackers@freebsd.org, Devin Teske <dteske@FreeBSD.org> Subject: Re: How to control and setup service? Message-ID: <988F49BB-5F42-4563-98AF-B8947FAC1EDC@FreeBSD.org> In-Reply-To: <55DF261C.80009@freebsd.org> References: <CAAoTqfvxUznJp%2BtguAaYQ=5HfKXTG%2BGxY644wvqm4e9=E8WuHw@mail.gmail.com> <55DF261C.80009@freebsd.org>
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> On Aug 27, 2015, at 8:00 AM, Allan Jude <allanjude@freebsd.org> wrote:
>=20
> sysrc automatically detects values from rc.conf.d directories, and can
> edit them if you ask it to. It just defaults to writing your changes =
to
> /etc/rc.conf
>=20
Only if you use the =93-f file=94 argument to point sysrc at said =
file(s).
Worth mentioning is this is in the sysrc(8) manual:
LIMITATIONS
The sysrc utility presently does not support the `rc.conf.d' =
collection
of system configuration files (which requires a service name to be =
known
during execution).
This will be corrected by a future enhancement.
So while below Allan shows us how to use `-f file=92 to support =
rc.conf.d file(s):
> My puppet scripts use:
> sysrc -f /etc/rc.conf.d/varnish varnishd_identity=3D"PDX1-01"
>=20
>=20
The OP was interested in an enhancement:
sysrc -s varnish varnishd_identity=3D=93PDX1-01=94
When given `-s service_name=92, sysrc would do the following:
1. For information purposes, first make sure service_name exists in any =
of:
a. /etc/rc.d
b. $local_startup directories =97 default: /usr/local/etc/rc.d
2. If the service does not exist, issue a warning to stderr but proceed =
anyway
NB: If we prevent moving ahead, it would be impossible to configure a =
setting when service is not installed
3. If service does exist, add the following paths to list of files =
checked (in addition to $rc_conf_files)
i. /etc/rc.conf.d/$_name
ii. ${local_startup%/rc.d}/rc.conf.d/$_name =97 default =
/usr/local/etc/rc.conf.d/$_name
You can better simulate this effect without the `-s service_name=92 =
enhancement,
using the currently available `-f file=92 argument (more pedantic than =
Allan Jude=92s
approach from above):
sysrc -f "/etc/rc.conf.d/$_name $( sysrc -n local_startup%/rc.d =
)/rc.conf.d/$_name" vimage_enable
Where $_name is the service_name.
A `-s service_name=92 argument to sysrc would make this easier.
ASIDE: While I was diving into this, I discovered a code typo in =
/etc/rc.subr
NB: The typo has gone unnoticed because it has no effect on outcome
=3D=3D=3D BEGIN DIFF =3D=3D=3D
--- rc.subr.orig 2015-08-27 12:56:24.445475772 -0700
+++ rc.subr 2015-08-27 12:56:33.980474637 -0700
@@ -1333,7 +1333,7 @@ load_rc_config()
_rc_conf_loaded=3Dtrue
fi
=20
- for _d in /etc ${local_startup%*/rc.d}; do
+ for _d in /etc ${local_startup%/rc.d}; do
if [ -f ${_d}/rc.conf.d/"$_name" ]; then
debug "Sourcing ${_d}/rc.conf.d/$_name"
. ${_d}/rc.conf.d/"$_name=94
=3D=3D=3D END DIFF =3D=3D=3D
FURTHER ASIDE: Why is the code in /etc/rc.subr treating
$local_startup as though it=92s a single item? There are many
locations in code that consider $local_startup to be a white-
space separated list of directories where rc.d scripts can live?
I think the above code should perhaps be changed to:
=3D=3D=3D BEGIN DIFF =3D=3D=3D
--- rc.subr.orig 2015-08-27 12:56:24.445475772 -0700
+++ rc.subr 2015-08-27 13:53:30.976240109 -0700
@@ -1333,7 +1333,8 @@ load_rc_config()
_rc_conf_loaded=3Dtrue
fi
=20
- for _d in /etc ${local_startup%*/rc.d}; do
+ for _d in /etc/rc.d $local_startup; do
+ _d=3D"${_d%/rc.d}"
if [ -f ${_d}/rc.conf.d/"$_name" ]; then
debug "Sourcing ${_d}/rc.conf.d/$_name"
. ${_d}/rc.conf.d/"$_name"
=3D=3D=3D END DIFF =3D=3D=3D
>>=20
>> As a user I would love to have a cool tool to control and configure
>> services in way like OpenBSD's rcctl(8) does
>> =
http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man8/rcctl.8?query=3D=
rcctl.
>> # cooltool set mysql-server status on
>> That's all. It would take care of those things like getting right
>> $rcvar name, choose right rc config file to edit (remember, we have a
>> lot of places to check, see above) and enable service, etc.
>> This $cooltool can be an extended version of service(8) tool.
>> More difficult example:
>> # cooltool set flow_capture status on flags "-e 2200 -n 23 -N 0 -V =
5"
>> port "8787" datadir "/storage/flows/all_routers"
>> would enable flow_capture service and set other stuff using right =
$rcvar.
>> # cooltool get flow_capture
>> would print all of the configured stuff for $service
>> # cooltool get flow_capture status
>> would print only a status YES/NO (don't forget about exit code ;) )
>> and etc.
>=20
> sysrc can do that, it will search all of the directories and find the
> final answer.
>=20
> The only thing it doesn't do is the translation between the 'service
> name' (mysql-server) and the 'rcvar prefix' (mysql_),
The rcvar =93prefix" is not actually what you=92re after.
In load_rc_config() of /etc/rc.subr we can see that it uses $_name
to append to /etc/rc.conf.d/ and /usr/local/etc/rc.conf.d/
What exactly is =93$_name=94 you ask? Good question=85
Almost 100% of the time, it=92s whatever =93name=3D=93 in the rc.d =
script.
This is not guaranteed to be ${0##*/} (the rc.d script name).
However, this just happens to be because almost 100% of the
time, rc.d scripts do the following:
load_rc_config "$name"
So for sysrc to know the proper name of the thing that /etc/rc.subr
will source from rc.conf.d collection of directories, we need to know
what name=3D in the rc.d script.
This seems to be the simplest approach:
=3D=3D=3D BEGIN SCRIPT: sconfigs.sh =3D=3D=3D
#!/bin/sh
sname=3D"$1" sconfigs=3D
_name=3D$( service "$sname" rcvar 2> /dev/null |
awk 'NR=3D=3D1&&sub(/^# /,""){print;exit}?' 2> /dev/null )
if [ "$_name" ]; then
sconfigs=3D"/etc/rc.conf.d/$_name"
local_etc=3D$( sysrc -qn local_startup%/rc.d 2> /dev/null )
[ "$local_etc" ] &&
sconfigs=3D"$sconfigs $local_etc/rc.d/rc.conf.d/$_name"
sconfigs=3D"${sconfigs# }"
fi
echo "sconfigs=3D[$sconfigs]"
=3D=3D=3D END SCRIPT: sconfigs.sh =3D=3D=3D
Examples:
$ ./sconfigs.sh
sconfigs=3D[]
$ ./sconfigs.sh zfs
sconfigs=3D[/etc/rc.conf.d/zfs /usr/local/etc/rc.d/rc.conf.d/zfs]
$ ./sconfigs.sh jail
sconfigs=3D[/etc/rc.conf.d/jail /usr/local/etc/rc.d/rc.conf.d/jail]
$ ./sconfigs.sh nosuchservice
sconfigs=3D[]
So naturally, if the logic in sconfigs.sh yields a non-NULL
value for $sconfigs, this would become the value of `-f files=92
via service name.
> which might be a
> useful addition, but might make more sense in the service command,
> because when I pass something to sysrc, I expect it to be interpreted
> literally. I guess it could be a flag for sysrc to specify the service
> instead of the rcvar.
>=20
> sysrc -s mysql datadir=3D/var/db/mysql
Given above talking-points, that would cause:
a. sysrc makes sure that =93mysql=94 is an actual service
b. sysrc uses =93service mysql rcvar" (piped into awk) to get `name=3D=91 =
value
NB: This could potentially result in a disconnect IFF the rc.d script =
passes something other than =93$name=94 to load_rc_config() (if we=92re =
worried about this, I have another recipe =97 further below).
c. Sets `-f files=92 value to "/etc/rc.conf.d/mysql =
/usr/local/etc/rc.conf.d/mysql=94
ASIDE: The only edge-case would be, for example...
=3D=3D=3D BEGIN FILE: /etc/rc.d/fooserv =3D=3D=3D
#!/bin/sh
. /etc/rc.subr
name=3DfoooooooooooooOOOooo
load_rc_config foooooooooo
run_rc_command "$@=93
=3D=3D=3D END FILE: /etc/rc.d/fooserv =3D=3D=3D
Wherein we get the following from =93service =85 rcvar=94:
$ service fooserv rcvar | awk NR=3D=3D1
# foooooooooooooOOOooo
The above command returns the =93name=3D=93 value but the script doesn=92t=
actually pass $name to load_rc_config() and thus what /etc/rc.subr
would check for in this case is /etc/rc.conf.d/foooooooooo and
/usr/local/etc/rc.conf.d/foooooooooo (versus the camel-case $name).
This edge-case exists for a number of services in the base:
$ awk '$1 ~ /^name=3D/ { name =3D $0; fn =3D FILENAME } $1 =3D=3D =
"load_rc_config" && $2 !~ /\$(name|{name})/{ print "--"; if (fn =3D=3D =
FILENAME) print fn ":" name; print FILENAME ":" $0 }' /etc/rc.d/*
--
/etc/rc.d/dhclient:name=3D"dhclient"
/etc/rc.d/dhclient:load_rc_config network
--
/etc/rc.d/fooserv:name=3DfoooooooooooooOOOooo
/etc/rc.d/fooserv:load_rc_config foooooooooo
--
/etc/rc.d/initrandom:name=3D"initrandom"
/etc/rc.d/initrandom:load_rc_config random
--
/etc/rc.d/othermta:load_rc_config 'XXX'
--
/etc/rc.d/postrandom:name=3D"postrandom"
/etc/rc.d/postrandom:load_rc_config random
--
/etc/rc.d/swaplate:name=3D"swaplate"
/etc/rc.d/swaplate:load_rc_config swap
NB: Ignore the /etc/rc.d/fooserv script which I created specifically to =
illustrate the disconnect.
For the above edge-case services in base, load_rc_config() of =
/etc/rc.subr will check the following:
dhclient:
/etc/rc.conf.d/network
/usr/local/etc/rc.conf.d/network
initrandom:
/etc/rc.conf.d/random
/usr/local/etc/rc.conf.d/random
othermta:
/etc/rc.conf.d/XXX
/usr/local/etc/rc.conf.d/XXX
postrandom:
/etc/rc.conf.d/random
/usr/local/etc/rc.conf.d/random
swaplate:
/etc/rc.conf.d/swap
/usr/local/etc/rc.conf.d/swap
Let=92s ignore for a second that it seems like an obvious error to be =
sourcing
/usr/local/etc/rc.conf.d/ANYTHING for a base service in /etc/rc.d/
NB: I can see someone utilizing that as a form of value-add anyways
What stands out at first glance is:
+ If /etc/rc.conf.d/XXX or /usr/local/etc/rc.conf.d/XXX exists,
it will be sourced when working on the =93othermta=94 service
NB: My testing indicates that othermta can obtain the desired results
(of not sourcing any additional rc.conf.d files) by instead passing a
single =93.=94 to load_c_config() =97 which does not allow a NULL arg1.
+ The =93service <name> rcvar | awk =85=94 approach to get =93name=3D=93
value fails for dhclient, initrandom, postrandom, and swaplate.
Oh, but it gets worse when you look deeper at the above-mentioned =
scripts:
$ grep -c load_rc_config /etc/rc.d/* | grep -v ':[01]$' | sed -e =
's/:[[:digit:]]\{1,\}$//' | xargs grep -n load_rc_config=20
/etc/rc.d/dhclient:54:load_rc_config $name
/etc/rc.d/dhclient:55:load_rc_config network
/etc/rc.d/local_unbound:32:load_rc_config $name
/etc/rc.d/local_unbound:90:load_rc_config $name
It turns out that the dhclient script will actually source all of (if =
any exist; in order):
1. /etc/rc.conf.d/dhclient
2. /usr/local/etc/rc.conf.d/dhclient
3. /etc/rc.conf.d/network
4. /usr/local/etc/rc.conf.d/network
I have a recipe that overcomes this edge-case that I=92d like to offer
as a potential solution:
=3D=3D=3D BEGIN FILE: sconfigs2.sh =3D=3D=3D
#!/bin/sh
sname=3D"$1" sconfigs=3D
local_startup=3D$( sysrc -qn local_startup )
for dir in /etc/rc.d $local_startup; do
spath=3D"$dir/$sname"
[ -f "$spath" -a -x "$spath" ] || spath=3D continue
break
done
if [ ! "$spath" ]; then
echo "$sname does not exist in /etc/rc.d or the local startup"
echo "directories ($local_startup)"
exit 1
fi
_names=3D
case "$( file -b "$spath" 2> /dev/null )" in *"shell script"*)
_names=3D$( exec 9<&1 1>&- 2>&-
last_name=3D
print_name() {
local name=3D"$1"
[ "$name" =3D "$last_name" ] && return
echo "$name" >&9
last_name=3D"$name"
}
eval "$( awk '{
gsub(/load_rc_config /, "print_name ")
gsub(/run_rc_command /, ": ")
print
}' "$spath" )"
) ;;
esac
for _name in $_names; do
for dir in /etc/rc.d $local_startup; do
sconfigs=3D"$sconfigs ${dir%/rc.d}/rc.conf.d/$_name"
done
done
sconfigs=3D"${sconfigs# }"
echo "sconfigs=3D[$sconfigs]=94
=3D=3D=3D END FILE: sconfigs2.sh =3D=3D=3D
Given the above code, we can handle the afore-mentioned edge-casen:
$ ./sconfigs2.sh dhclient
sconfigs=3D[/etc/rc.conf.d/dhclient /usr/local/etc/rc.conf.d/dhclient =
/etc/rc.conf.d/network /usr/local/etc/rc.conf.d/network]
$ ./sconfigs2.sh initrandom
sconfigs=3D[/etc/rc.conf.d/random /usr/local/etc/rc.conf.d/random]
$ ./sconfigs2.sh postrandom
sconfigs=3D[/etc/rc.conf.d/random /usr/local/etc/rc.conf.d/random]
$ ./sconfigs2.sh swaplate
sconfigs=3D[/etc/rc.conf.d/swap /usr/local/etc/rc.conf.d/swap]
$ ./sconfigs2.sh local_unbound
sconfigs=3D[/etc/rc.conf.d/local_unbound =
/usr/local/etc/rc.conf.d/local_unbound]
$ ./sconfigs2.sh=20
does not exist in /etc/rc.d or the local startup
directories (/usr/local/etc/rc.d)
$ ./sconfigs2.sh nosuchservice
nosuchservice does not exist in /etc/rc.d or the local startup
directories (/usr/local/etc/rc.d)
This is looking like a much better approach.
>=20
>> IMO such tools would be useful even for ansible/puppet and friends.
>> Not just for users ;)
>>=20
>=20
> Teaching service to use sysrc might be useful. Making sysrc detect =
that
> /etc/rc.conf.d/<service> exists, and use it, else fallback to
> /etc/rc.conf might also be nice.
>=20
> service mysql-server enable|disable
> sets mysql_enable=3D"YES|NO"
> service mysql-server set datadir=3D/var/db/mysql
> sets mysql_datadir=3D"/var/db/mysql"
>=20
> I am currently doing all of this in puppet with sysrc.
Adding a =93service =85 enable=94 and =93service =85 disable=94 could be =
nice.
I=92m sure some of the above logic would be instrumental in that.
=97=20
Devin=
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