From 7dd2e1776eef60a8a5c739b5cad67d649946d393 Mon Sep 17 00:00:00 2001
From: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Date: Tue, 30 Apr 2019 01:32:59 -0300
Subject: sane-backends: rebind printers to usblp after scan

While scanning, sane unbinds usb device from usblp module. This
patch creates a saned wrapper that keep track of all usb devices
binded to usblp before saned is launched and rebind them back
if not still bound after saned exits.

This workaround is only effective if saned is launched by a super
daemon like xinetd as it needs to exit after scan job finish. If
not, printing will not be available while saned service is running.

Write access to /sys/bus/usb/drivers/usblp/bind is required. So,
normally it would require root access.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
---
 utils/sane-backends/files/etc/xinetd.d/sane-port | 14 ++++++++++++++
 utils/sane-backends/files/usr/sbin/saned         | 24 ++++++++++++++++++++++++
 utils/sane-backends/files/xinet.d_sane-port      | 14 --------------
 3 files changed, 38 insertions(+), 14 deletions(-)
 create mode 100644 utils/sane-backends/files/etc/xinetd.d/sane-port
 create mode 100755 utils/sane-backends/files/usr/sbin/saned
 delete mode 100644 utils/sane-backends/files/xinet.d_sane-port

(limited to 'utils/sane-backends/files')

diff --git a/utils/sane-backends/files/etc/xinetd.d/sane-port b/utils/sane-backends/files/etc/xinetd.d/sane-port
new file mode 100644
index 000000000..9119973f6
--- /dev/null
+++ b/utils/sane-backends/files/etc/xinetd.d/sane-port
@@ -0,0 +1,14 @@
+# default: off
+# description: The saned provides scanner service via the network.  \
+#	Applications like kooka, xsane or xscanimage can use the remote \
+#	scanner. 
+service sane-port
+{
+	socket_type = stream
+	port        = 6566
+	wait        = no
+	user        = root
+	group       = root
+	server      = /usr/sbin/saned
+	disable     = yes
+}
diff --git a/utils/sane-backends/files/usr/sbin/saned b/utils/sane-backends/files/usr/sbin/saned
new file mode 100755
index 000000000..711492633
--- /dev/null
+++ b/utils/sane-backends/files/usr/sbin/saned
@@ -0,0 +1,24 @@
+#!/bin/sh
+
+usblp_driver="/sys/bus/usb/drivers/usblp"
+
+inuse=""
+if [ -e /sys/bus/usb/devices ]; then
+	for usbdev_driver in /sys/bus/usb/devices/*/driver; do
+		[ -e "$usbdev_driver" ] || continue
+		[ "$(readlink -f "$usbdev_driver")" = "$usblp_driver" ] || continue
+		usbdev="${usbdev_driver%/*}"
+		inuse="$inuse ${usbdev##*/}"
+	done
+fi
+
+/usr/lib/sane/saned "$@"
+err=$?
+
+for usbdev in $inuse; do
+	[ -e "/sys/bus/usb/devices/$usbdev/driver" ] && continue
+	logger -t saned "binding device $usbdev back to usblp..."
+	printf '%s' "$usbdev" > "$usblp_driver/bind"
+done
+
+exit $err
diff --git a/utils/sane-backends/files/xinet.d_sane-port b/utils/sane-backends/files/xinet.d_sane-port
deleted file mode 100644
index 9119973f6..000000000
--- a/utils/sane-backends/files/xinet.d_sane-port
+++ /dev/null
@@ -1,14 +0,0 @@
-# default: off
-# description: The saned provides scanner service via the network.  \
-#	Applications like kooka, xsane or xscanimage can use the remote \
-#	scanner. 
-service sane-port
-{
-	socket_type = stream
-	port        = 6566
-	wait        = no
-	user        = root
-	group       = root
-	server      = /usr/sbin/saned
-	disable     = yes
-}
-- 
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