Annotation of /rpms/sane-backends/contribs7/libusbscanner

#!/bin/bash
# $Id: libusbscanner,v 1.2 2004/08/26 10:26:08 twaugh Exp $
#
# /etc/hotplug/usb/libusbscanner
#
# Sets up newly plugged in USB scanner so that the user who owns
# the console according to pam_console can access it from user space
#
# Note that for this script to work, you'll need all of the following:
# a) a line in the file /etc/hotplug/usermap that corresponds to the 
#    camera you are using.
# b) a setup using pam_console creates the respective lock files
#    containing the name of the respective user. You can check for that
#    by executing "echo `cat /var/{run,lock}/console.lock`" and 
#    verifying the appropriate user is mentioned somewhere there.
# c) a Linux kernel supporting hotplug and usbdevfs
# d) the hotplug package (http://linux-hotplug.sourceforge.net/)
#
# In the usermap file, the first field "usb module" should be named 
# "libusbscanner" like this script.
# 

if [ -z "${DEVICE}" ]
then
    exit 0
fi

DEVDIR=/dev
DEVNAME="scanner-usb-$(echo ${DEVICE#../proc/bus/usb/} | sed -e 's;/;:;g')"

wait_and_add () {
    local limit=90
    # wait until the action can be performed but no longer
    # than $limit seconds
    while ! ln -snf "${DEVICE}" "${DEVDIR}/${DEVNAME}" ; do
            [ "$limit" = 0 ] && return
            sleep 1
            limit=$((limit - 1))
    done
    
    /sbin/pam_console_apply "${DEVDIR}/${DEVNAME}"
}

if [ "${ACTION}" = "add" ] && [ -f "${DEVICE}" ]
then

    # Make a symlink from /dev/scanner-usb-BBB:DDD to /proc/bus/usb/BBB/DDD.
    # If /etc/security/console.perms is set up properly, pam_console will
    # follow the symlink and set the permissions of /proc/bus/usb/BBB/DDD such
    # that "console" users will be able to use their USB scanner.
    #
    # If the scanner is "cold plugged", and this event will occurred before
    # the root filesystem was writeable, then we wait in a background
    # until a link in ${DEVDIR} can be created.  Permissions on
    # /proc/bus/usb/BBB/DDD will be of a "revert" type; see
    # man 5 console.perms.  This is fine; when a device does not exist
    # at all we do not particularly care about its permissions.
    #
    ( wait_and_add >/dev/null 2>&1 & )
    
    # See /etc/hotplug/usb.agent for a description of how REMOVER works.
    ln -sf "${0}" "${REMOVER}"
fi

if [ "${ACTION}" = "remove" ]
then
    rm -f "${DEVDIR}/${DEVNAME}"
fi
1	slords	1.1	#!/bin/bash
2			# $Id: libusbscanner,v 1.2 2004/08/26 10:26:08 twaugh Exp $
3			#
4			# /etc/hotplug/usb/libusbscanner
5			#
6			# Sets up newly plugged in USB scanner so that the user who owns
7			# the console according to pam_console can access it from user space
8			#
9			# Note that for this script to work, you'll need all of the following:
10			# a) a line in the file /etc/hotplug/usermap that corresponds to the
11			# camera you are using.
12			# b) a setup using pam_console creates the respective lock files
13			# containing the name of the respective user. You can check for that
14			# by executing "echo `cat /var/{run,lock}/console.lock`" and
15			# verifying the appropriate user is mentioned somewhere there.
16			# c) a Linux kernel supporting hotplug and usbdevfs
17			# d) the hotplug package (http://linux-hotplug.sourceforge.net/)
18			#
19			# In the usermap file, the first field "usb module" should be named
20			# "libusbscanner" like this script.
21			#
22
23			if [ -z "${DEVICE}" ]
24			then
25			exit 0
26			fi
27
28			DEVDIR=/dev
29			DEVNAME="scanner-usb-$(echo ${DEVICE#../proc/bus/usb/} \| sed -e 's;/;:;g')"
30
31			wait_and_add () {
32			local limit=90
33			# wait until the action can be performed but no longer
34			# than $limit seconds
35			while ! ln -snf "${DEVICE}" "${DEVDIR}/${DEVNAME}" ; do
36			[ "$limit" = 0 ] && return
37			sleep 1
38			limit=$((limit - 1))
39			done
40
41			/sbin/pam_console_apply "${DEVDIR}/${DEVNAME}"
42			}
43
44			if [ "${ACTION}" = "add" ] && [ -f "${DEVICE}" ]
45			then
46
47			# Make a symlink from /dev/scanner-usb-BBB:DDD to /proc/bus/usb/BBB/DDD.
48			# If /etc/security/console.perms is set up properly, pam_console will
49			# follow the symlink and set the permissions of /proc/bus/usb/BBB/DDD such
50			# that "console" users will be able to use their USB scanner.
51			#
52			# If the scanner is "cold plugged", and this event will occurred before
53			# the root filesystem was writeable, then we wait in a background
54			# until a link in ${DEVDIR} can be created. Permissions on
55			# /proc/bus/usb/BBB/DDD will be of a "revert" type; see
56			# man 5 console.perms. This is fine; when a device does not exist
57			# at all we do not particularly care about its permissions.
58			#
59			( wait_and_add >/dev/null 2>&1 & )
60
61			# See /etc/hotplug/usb.agent for a description of how REMOVER works.
62			ln -sf "${0}" "${REMOVER}"
63			fi
64
65			if [ "${ACTION}" = "remove" ]
66			then
67			rm -f "${DEVDIR}/${DEVNAME}"
68			fi