Add a general mechanism for creating and applying

devfs(8) rules in rc(8). It is most useful for applying
rules to devfs(5) mount points in /dev or inside jails.
The following line of script is sufficient to
mount a relatively useful+secure devfs(5) in a jail:

	devfs_mount_jail /some/jail/dev

Some new shell routines available to scripts that source
rc.subr(5):
	o devfs_link		- Makes it a little easier to create symlinks
	o devfs_init_rulesets	- Create devfs(8) rulesets from devfs.rules
	o devfs_set_ruleset	- Set a ruleset to a devfs(5) mount
	o devfs_apply_ruleset	- Apply a ruleset to a devfs(5) mount
	o devfs_domount		- Mount devfs(5) and apply some ruleset
	o devfs_mount_jail	- Mount devfs(5) and apply a ruleset
				  appropriate to jails.

Additional rulesets can be specified in /etc/devfs.rules.
If the devfs_system_ruleset variable is defined in rc.conf
and it contains the name of a ruleset defined in /etc/defaults/devfs.rules
or user supplied rulesets in /etc/devfs.rules then that ruleset will
be applied to /dev at startup by the /etc/rc.d/devfs script. It can
also be applied post-startup:

	/etc/rc.d/devfs start

This is a more flexible mechanism than the previous method of using
/etc/devfs.conf. However, that method is still available.

Note: since devfs(8) doesn't provide any way for creating symlinks
as part of a ruleset, anyone wishing to create symlinks in a devfs(5)
as part of the bootup sequence will still have to rely on /etc/devfs.conf.
This commit is contained in:
Mike Makonnen 2003-08-20 06:15:18 +00:00
parent 74a9cb0969
commit 130112f793
5 changed files with 298 additions and 2 deletions

View File

@ -1,6 +1,6 @@
# $FreeBSD$
FILES= pccard.conf periodic.conf rc.conf
FILES= devfs.rules pccard.conf periodic.conf rc.conf
NOOBJ= noobj
FILESDIR= /etc/defaults
FILESMODE= 644

64
etc/defaults/devfs.rules Normal file
View File

@ -0,0 +1,64 @@
#
# The following are some default rules for devfs(5) mounts.
# The format is very simple. Empty lines and lines begining
# with a hash '#' are ignored. If the hash mark occurs anywhere
# other than the beginning of a line, it and any subsequent
# characters will be ignored. A line in between brackets '[]'
# denotes the beginning of a ruleset. In the brackets should
# be a name for the rule and its ruleset number. Any other lines
# will be considered to be the 'action' part of a rule
# passed to the devfs(8) command. These will be passed
# "as-is" to the devfs(8) command with the exception that
# any references to other rulesets will be expanded first. These
# references must include a dollar sign '$' in-front of the
# name to be expanded properly.
#
# $FreeBSD$
#
# Very basic and secure ruleset: Hide everything.
# Used as a basis for other rules.
#
[devfsrules_hide_all=1]
add hide
# Basic devices typically necessary.
# Requires: devfsrules_hide_all
#
[devfsrules_unhide_basic=2]
add path null unhide
add path zero unhide
add path random unhide
add path urandom unhide
# Devices typically needed to support logged-in users.
# Requires: devfsrules_hide_all
#
[devfsrules_unhide_login=3]
add path 'ptyp*' unhide
add path 'ptyq*' unhide
add path 'ptyr*' unhide
add path 'ptys*' unhide
add path 'ptyP*' unhide
add path 'ptyQ*' unhide
add path 'ptyR*' unhide
add path 'ptyS*' unhide
add path 'ttyp*' unhide
add path 'ttyq*' unhide
add path 'ttyr*' unhide
add path 'ttys*' unhide
add path 'ttyP*' unhide
add path 'ttyQ*' unhide
add path 'ttyR*' unhide
add path 'ttyS*' unhide
add path 'fd/*' unhide
add path stdin unhide
add path stdout unhide
add path stderr unhide
# Devices usually found in a jail.
#
[devfsrules_jail=4]
add include $devfsrules_hide_all
add include $devfsrules_unhide_basic
add include $devfsrules_unhide_login

View File

@ -434,6 +434,10 @@ jail_set_hostname_allow="YES" # Allow root user in a jail to change its hostname
jail_socket_unixiproute_only="YES" # Route only TCP/IP within a jail
jail_sysvipc_allow="NO" # Allow SystemV IPC use from within a jail
watchdogd_enable="NO" # Start the software watchdog daemon
devfs_rulesets="/etc/defaults/devfs.rules /etc/devfs.rules" # Files containing
# devfs(8) rules.
devfs_system_ruleset="" # The name of a ruleset to apply to /dev
##############################################################
### Define source_rc_confs, the mechanism used by /etc/rc.* ##

View File

@ -11,9 +11,19 @@
. /etc/rc.subr
name="devfs"
start_cmd='read_devfs_conf'
start_cmd='devfs_start'
stop_cmd=':'
devfs_start()
{
if [ -n "$devfs_system_ruleset" ]; then
devfs_init_rulesets
devfs_set_ruleset $devfs_system_ruleset /dev
devfs_apply_ruleset $devfs_system_ruleset /dev
fi
read_devfs_conf
}
read_devfs_conf()
{
if [ -r /etc/devfs.conf ]; then

View File

@ -1033,3 +1033,221 @@ backup_file()
esac
fi
}
# devfs_link dir src link
# Make a symbolic link 'link' to src in chroot/dev.
# Returns 0 on sucess.
#
devfs_link()
{
local dir src link _me
dir="$1"
src="$2"
link="$3"
_me="devfs_link"
if [ -z "$dir" -o -z "$src" -o -z "$link" ]; then
warn "devfs_link(): requires three arguments."
return 1
fi
if [ -z "$dir" ]; then
warn "$_me: the directory ($dir) does not exist"
return 1
fi
cd ${chroot}/dev
if ! ln -sf $src $link ; then
warn "$_me: unable to link $link --> $src in $dir"
return 1
fi
return 0
}
# devfs_rulesets_from_file file
# Reads a set of devfs commands from file, and creates
# the specified rulesets with their rules. Returns non-zero
# if there was an error.
#
devfs_rulesets_from_file()
{
local file _err _me
file="$1"
_me="devfs_rulesets_from_file"
_err=0
if [ -z "$file" ]; then
warn "$_me: you must specify a file"
return 1
fi
if [ ! -e "$file" ]; then
debug "$_me: no such file ($file)"
return 0
fi
debug "reading rulesets from file ($file)"
{ while read line
do
case $line in
\#*)
continue
;;
\[*\]*)
rulenum=`expr "$line" : "\[.*=\([0-9]*\)\]"`
if [ -z "$rulenum" ]; then
warn "$_me: cannot extract rule number ($line)"
_err=1
break
fi
rulename=`expr "$line" : "\[\(.*\)=[0-9]*\]"`
if [ -z "$rulename" ]; then
warn "$_me: cannot extract rule name ($line)"
_err=1
break;
fi
eval $rulename=\$rulenum
debug "found ruleset: $rulename=$rulenum"
if ! /sbin/devfs rule -s $rulenum delset ; then
_err=1
break
fi
;;
*)
rulecmd="${line%%"\#*"}"
# evaluate the command incase it includes
# other rules
if [ -n "$rulecmd" ]; then
debug "adding rule ($rulecmd)"
if ! eval /sbin/devfs rule -s $rulenum $rulecmd
then
_err=1
break
fi
fi
;;
esac
if [ $_err -ne 0 ]; then
debug "error in $_me"
break
fi
done } < $file
return $_err
}
# devfs_init_rulesets
# Initializes rulesets from configuration files. Returns
# non-zero if there was an error.
#
devfs_init_rulesets()
{
local file _me
_me="devfs_init_rulesets"
# Go through this only once
if [ -n "$devfs_rulesets_init" ]; then
debug "$_me: devfs rulesets already initialized"
return
fi
for file in $devfs_rulesets ; do
devfs_rulesets_from_file $file || return 1
done
devfs_rulesets_init=1
debug "$_me: devfs rulesets initialized"
return 0
}
# devfs_set_ruleset ruleset [dir]
# Sets the default ruleset of dir to ruleset. The ruleset arguement
# must be a ruleset name as specified in devfs.rules(5) file.
# Returns non-zero if it could not set it successfully.
#
devfs_set_ruleset()
{
local devdir rs _me
[ -n "$1" ] && eval rs=\$$1 || rs=
[ -n "$2" ] && devdir="-m "$2"" || devdir=
_me="devfs_set_ruleset"
if [ -z "$rs" ]; then
warn "$_me: you must specify a ruleset number"
return 1
fi
debug "$_me: setting ruleset ($rs) on mount-point (${devdir#-m })"
if ! /sbin/devfs $devdir ruleset $rs ; then
warn "$_me: unable to set ruleset $rs to ${devdir#-m }"
return 1
fi
return 0
}
# devfs_apply_ruleset ruleset [dir]
# Apply ruleset number $ruleset to the devfs mountpoint $dir.
# The ruleset argument must be a ruleset name as specified
# in a devfs.rules(5) file. Returns 0 on success or non-zero
# if it could not apply the ruleset.
#
devfs_apply_ruleset()
{
local devdir rs _me
[ -n "$1" ] && eval rs=\$$1 || rs=
[ -n "$2" ] && devdir="-m "$2"" || devdir=
_me="devfs_apply_ruleset"
if [ -z "$rs" ]; then
warn "$_me: you must specify a ruleset"
return 1
fi
debug "$_me: applying ruleset ($rs) to mount-point (${devdir#-m })"
if ! /sbin/devfs $devdir rule -s $rs applyset ; then
warn "$_me: unable to apply ruleset $rs to ${devdir#-m }"
return 1
fi
return 0
}
# devfs_domount dir [ruleset]
# Mount devfs on dir. If ruleset is specified it is set
# on the mount-point. It must also be a ruleset name as specified
# in a devfs.rules(5) file. Returns 0 on success.
#
devfs_domount()
{
local devdir rs _me
devdir="$1"
[ -n "$2" ] && rs=$2 || rs=
_me="devfs_domount()"
if [ -z "$devdir" ]; then
warn "$_me: you must specify a mount-point"
return 1
fi
debug "$_me: mount-point is ($devdir), ruleset is ($rs)"
if ! mount -t devfs dev "$devdir" ; then
warn "$_me: Unable to mount devfs on $devdir"
return 1
fi
if [ -n "$rs" ]; then
devfs_init_rulesets
devfs_set_ruleset $rs $devdir
fi
return 0
}
# devfs_mount_jail dir [ruleset]
# Mounts a devfs file system appropriate for jails
# on the directory dir. If ruleset is specified, the ruleset
# it names will be used instead. If present, ruleset must
# be the name of a ruleset as defined in a devfs.rules(5) file.
# This function returns non-zero if an error occurs.
#
devfs_mount_jail()
{
local jdev rs _me
jdev="$1"
[ -n "$2" ] && rs=$2 || rs="devfsrules_jail"
_me="devfs_mount_jail"
devfs_init_rulesets
if ! devfs_domount "$jdev" $rs ; then
warn "$_me: devfs was not mounted on $jdev"
return 1
fi
return 0
}