Re: Test script for udevd binary, Request for Comments!

[Kay Sievers <kay.sievers@vrfy.org>]

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On Tue, Apr 13, 2004 at 06:34:27PM +0800, Yin, Hu wrote:
> I have written three scripts, that is, udevd-test.pl,
> udev-log-script.pl, udev-log-amplify.pl. where udevd-test.pl is main
> test script, udev-log-script.pl is a replace for udev binary for general
> test case, udev-log-amplify.pl is another replace for udev binary for
> "only one udev instance for a single device at the same time" test case,
> which amplifies the execution time (sleep 5) in order for convenience of
> test.
> 
> Would you like to help me check them? Thank you very much!

Looks promising. I've made it a big patch, also containing the udevd.c
change. Please send all future changes as a incremental patch on top of
this one, so we both can track the changes. I've changed a few things:

  o placed the scripts in test/udevd-test/ subdir
  o replaced 'rm -rf' by 'rm -f'
  o place the logfile into /tmp/
  o wait 1 second after killing the daemon, cause the kernel needs
    to cleanup the old socket, otherwise the first two events sent for the
    new daemon are lost on my machine
  o unset SEQNUM in udevsend(), otherwise test #6 will fail by sending
    the SEQNUM from test #5
  o substituted spaces by tabs


Can we switch to our test/sys/ tree and use the files in there, instead of
the real /sys, cause some machines don't have /block/hda or /block/loop?

Kay

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diff -Nru a/test/udevd-test/udev-log-amplify.pl b/test/udevd-test/udev-log-amplify.pl
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/test/udevd-test/udev-log-amplify.pl	Tue Apr 13 15:21:43 2004
@@ -0,0 +1,87 @@
+#!/usr/bin/perl -w
+#
+# udev-log-amplify
+#
+# Copyright (C) Intel Corp, 2004
+#
+# Author: Yin Hu <hu.yin@intel.com> 
+#
+# This is a script for replacing udev binary during udevsend/udevd testing.
+# It first amplifies the execution time ( sleep 5 ) and then logs the event 
+# information sent by udved in order that test script udevd-test.pl can
+# analyze whether udved execute as we expected.
+# You should not execute this script directly because it will be invoked by 
+# udevd automatically.
+#
+# Before you run your test please modify $log_file to designate where the udev
+# log file should be placed, in fact, the default value is ok. 
+#
+#
+#	This program is free software; you can redistribute it and/or modify it
+#	under the terms of the GNU General Public License as published by the
+#	Free Software Foundation version 2 of the License.
+#
+#	This program is distributed in the hope that it will be useful, but
+#	WITHOUT ANY WARRANTY; without even the implied warranty of
+#	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+#	General Public License for more details.
+#
+#	You should have received a copy of the GNU General Public License along
+#	with this program; if not, write to the Free Software Foundation, Inc.,
+#	675 Mass Ave, Cambridge, MA 02139, USA.
+#
+
+use warnings;
+use strict;
+
+# modifiable settings
+my $udev_exe_time = 5;
+my $log_file  = "/tmp/udev_log.txt";
+
+# global variables
+my $devpath;
+my $action;
+my $subsystem;
+
+# common functions
+sub getDate {
+	# Get current date/time
+	# If we want GTM time, simply pass GMT as first argument to this function.
+
+	my $format = @_;
+	my $date;
+
+	if( $format =~ /GMT/i ) {
+		$date = gmtime() . " GMT";
+	} else {
+		$date = localtime();
+	}
+	return $date;
+}
+
+# main program
+if ($ARGV[0]) {
+	$subsystem = $ARGV[0];
+	$devpath = $ENV{DEVPATH};
+	$action = $ENV{ACTION};
+
+	# Get current system date
+	my $time = getDate();
+
+	# Logging
+	if (open(LOGF, ">>$log_file")) {
+		print LOGF "$devpath,$action,$subsystem,$time\n";
+	} else {
+		print "File open failed. \n";
+		exit 1;
+	}
+	close(LOGF);
+
+	# Amplify the execution time of udev
+	sleep 5;
+
+	exit 0;
+} else {
+	print "Too less argument count.\n";
+	exit 1;
+}
diff -Nru a/test/udevd-test/udev-log-script.pl b/test/udevd-test/udev-log-script.pl
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/test/udevd-test/udev-log-script.pl	Tue Apr 13 15:21:43 2004
@@ -0,0 +1,82 @@
+#!/usr/bin/perl -w
+#
+# udev-log-script
+#
+# Copyright (C) Intel Corp, 2004
+#
+# Author: Yin Hu <hu.yin@intel.com> 
+#
+# This is a script for replacing udev binary during udevsend/udevd testing.
+# It just simply logs the event information sent by udved in order to
+# test script udevd-test.pl can analyze whether udved execute as we expected.
+# You should not execute this script directly because it will be invoked by
+# udevd automatically.
+#
+# Before you run your test please modify $log_file to designate where the udev
+# log file should be placed, in fact, the default value is ok.
+#
+# 
+#	This program is free software; you can redistribute it and/or modify it
+# 	under the terms of the GNU General Public License as published by the
+# 	Free Software Foundation version 2 of the License.
+#  
+# 	This program is distributed in the hope that it will be useful, but
+# 	WITHOUT ANY WARRANTY; without even the implied warranty of
+# 	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# 	General Public License for more details.
+#
+#	You should have received a copy of the GNU General Public License along
+# 	with this program; if not, write to the Free Software Foundation, Inc.,
+# 	675 Mass Ave, Cambridge, MA 02139, USA.
+#
+
+use warnings;
+use strict;
+
+# modifiable settings
+my $log_file  = "/tmp/udev_log.txt";
+
+# global variables
+my $devpath;
+my $action;
+my $subsystem;
+
+# common functions
+sub getDate {
+        # Get current date/time
+        # If we want GTM time, simply pass GMT as first argument to this function.
+        my $format = @_;
+        my $date;
+
+        if( $format =~ /GMT/i ) {
+                $date = gmtime() . " GMT";
+        } else {
+                $date = localtime();
+        }
+        return $date;
+}
+
+# main program
+if ($ARGV[0]) {
+	# prepare
+	$subsystem = $ARGV[0];
+	$devpath = $ENV{DEVPATH};
+	$action = $ENV{ACTION};
+
+	# Get current system date
+	my $time = getDate();
+
+	# Logging
+        if (open(LOGF, ">>$log_file")) {
+		print LOGF "$devpath,$action,$subsystem,$time\n";
+	} else {
+		print "File open failed. \n";
+		exit 1;
+	}
+        close(LOGF);
+
+	exit 0;
+} else {
+	print "Too less argument count.\n";
+	exit 1;
+}
diff -Nru a/test/udevd-test/udevd-test.pl b/test/udevd-test/udevd-test.pl
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/test/udevd-test/udevd-test.pl	Tue Apr 13 15:21:43 2004
@@ -0,0 +1,668 @@
+#!/usr/bin/perl -w
+#
+# udevd-test
+#
+# Copyright (C) Intel Corp, 2004
+#
+# Author: Yin Hu <hu.yin@intel.com> 
+#
+# Provides automated testing of the udevd binary.This test script is self-contained.
+# Before you run this script please modify $sysfs to locate your sysfs filesystem, 
+# modify $udevd_bin to locate your udevsend binary,
+# modify $udev_bin to locate dummy udev script,
+# modify $udev_bin2 to locate another dummy udev script ( amplify the execution time for test),
+# modify $log_file to locate where udev script have placed the log file,
+# modify $time_out to decide the time out for events,
+# modify $udev_exe_time to decide the execution time for dummy udev script.
+#
+# Detail information of each test case please refer to the header of corresponding
+# test case function.
+#
+#
+#	This program is free software; you can redistribute it and/or modify it
+#	under the terms of the GNU General Public License as published by the
+#	Free Software Foundation version 2 of the License.
+#
+#	This program is distributed in the hope that it will be useful, but
+#	WITHOUT ANY WARRANTY; without even the implied warranty of
+#	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+#	General Public License for more details.
+#
+#	You should have received a copy of the GNU General Public License along
+#	with this program; if not, write to the Free Software Foundation, Inc.,
+#	675 Mass Ave, Cambridge, MA 02139, USA.
+#
+
+use warnings;
+use strict;
+
+# modifiable settings
+my $sysfs     = "/sys";
+my $udevd_bin = "../../udevsend";
+my $udev_bin  = "$ENV{PWD}/udev-log-script.pl";
+my $udev_bin2 = "$ENV{PWD}/udev-log-amplify.pl";
+my $log_file  = "/tmp/udev_log.txt";
+my $time_out  = 10;
+my $udev_exe_time = 5;
+
+# global variables
+my $test_case = 0;
+
+# common functions
+
+sub kill_daemon {
+	system("killall udevd");
+	system("rm -f $log_file");
+	sleep 1;
+}
+
+sub udevsend {
+	# This function prepares corresponding environment variables
+	# and then call $udevd_bin to send event.
+
+	my ($seqnum, $devpath, $action, $subsystem, $udev_bin_tmp) = @_;
+
+	$ENV{DEVPATH} = $devpath;
+	$ENV{ACTION} = $action;
+	$udev_bin_tmp = $udev_bin if ( not $udev_bin_tmp );
+	$ENV{UDEV_BIN} = $udev_bin_tmp;
+	if ( $seqnum != -1) {
+		$ENV{SEQNUM} = $seqnum;
+	} else {
+		delete $ENV{SEQNUM};
+	}
+
+	return system("$udevd_bin $subsystem");
+}
+
+sub getDate {
+	# Get current date function
+	# If we want GTM time, simply pass GMT as first argument to this function.
+
+	my $format = @_;
+	my $date;
+
+	if( $format =~ /GMT/i ) {
+		$date = gmtime() . " GMT";
+	} else {
+		$date = localtime();
+	}
+
+	return $date;
+}
+
+sub cmpDate {
+	# This function should return a difference betweent date1 and date2
+
+	my ($date1, $date2) = @_;
+	my @monList = ( "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul",
+			  "Aug", "Sep", "Oct", "Nov", "Dec" );
+	my ( $m1, $m2, $tmp );
+
+	$date1 =~ s/([\D]*)$//g;
+	$date2 =~ s/([\D]*)$//g;
+
+	return if( (not $date1) or (not $date2) );
+
+	my $mon = 0;
+
+	my ( @T1 ) =
+	 ( $date1 =~ /([\d]+)[\s]+([\d]+):([\d]+):([\d]+)[\s]+([\d]+)/g );
+	my ( @T2 ) = 
+	 ( $date2 =~ /([\d]+)[\s]+([\d]+):([\d]+):([\d]+)[\s]+([\d]+)/g );
+
+	foreach $tmp (@monList) {
+		$m1 = sprintf("%2.2d",$mon) if( $date1 =~ /$tmp/i );
+		$m2 = sprintf("%2.2d",$mon) if( $date2 =~ /$tmp/i );
+		$mon++;
+	}
+
+	my $dt1 = sprintf("%4.4d%s%2.2d%2.2d%2.2d%2.2d", $T1[4], $m1, $T1[0],
+					$T1[1], $T1[2], $T1[3]);
+	my $dt2 = sprintf("%4.4d%s%2.2d%2.2d%2.2d%2.2d", $T2[4], $m2, $T2[0],
+					$T2[1], $T2[2], $T2[3]);
+
+	my $ret = $dt1 - $dt2;
+
+	if ( $ret > 40 ) {
+		$ret = abs($ret-40);
+	}
+
+	return $ret;
+}
+
+sub check_count_and_time { 
+	my $event_recv_time;
+	my $udev_fork_time;
+	my $log_ln_count = 0;
+	my $line;
+	my @content;
+	my @line_items;
+	my $diff;
+
+	($event_recv_time) = @_;
+
+	print "   event receiving time:  $event_recv_time\n\n";
+
+	open(LOGF, $log_file) || die "Opening file $log_file: $!";
+	@content = <LOGF>;
+	foreach $line ( @content ) {
+		@line_items = split(/,/,$line);
+		print "   device: $line_items[0], action: $line_items[1] \n";
+		print "   forking udev time:     $line_items[-1]";
+		$diff = cmpDate($line_items[-1], $event_recv_time);
+		print "   the delay time is:     $diff s \n\n";
+		if ( $diff > $time_out ) {
+			print "   the delay time is: $diff \n";
+			print "   udevd doesn't act properly. \n";
+			exit 1;
+		}
+		$log_ln_count++;
+	}
+	close(LOGF);
+
+	return $log_ln_count;
+}
+
+sub check_sysfs_device_exist {
+	# check if the designated devices exist
+	my @dev_list = @_;
+	my $dev;
+
+	foreach $dev (@dev_list) {
+		if (! -e $dev) {
+			print "the designated device $dev doesn't exist. please change a device!\n";
+			exit 1;
+		}
+	}
+}
+
+sub show_result {
+	my $event_recv_time;
+	my $udev_fork_time;
+	my $line;
+	my @content;
+	my @line_items;
+	my $diff;
+
+	($event_recv_time) = @_;
+
+	print "   event receiving time:  $event_recv_time\n\n";
+
+	open(LOGF, $log_file) || die "Opening file $log_file: $!";
+	@content = <LOGF>;
+	foreach $line ( @content ) {
+		@line_items = split(/,/,$line);
+		print "   device: $line_items[0], action: $line_items[1] \n";
+		print "   forking udev time:     $line_items[-1]";
+		$diff = cmpDate($line_items[-1], $event_recv_time);
+		print "   the delay time is:     $diff s \n\n";
+	}
+	close(LOGF);
+}
+
+sub show_result_tm_out {
+	my $event_recv_time;
+	my $udev_fork_time;
+	my $line;
+	my @content;
+	my @line_items;
+	my $diff;
+
+	($event_recv_time) = @_;
+
+	print "   event receiving time:  $event_recv_time\n\n";
+
+	open(LOGF, $log_file) || die "Opening file $log_file: $!";
+	@content = <LOGF>;
+	foreach $line ( @content ) {
+		@line_items = split(/,/,$line);
+		print "   device: $line_items[0], action: $line_items[1] \n";
+		print "   forking udev time:     $line_items[-1]";
+		$diff = cmpDate($line_items[-1], $event_recv_time);
+		print "   the delay time is:     $diff s \n\n";
+		if ( $diff < $time_out ) {
+			print "   the delay time is:     $diff \n";
+			print "   udevd doesn't act properly. \n";
+			exit 1;
+		}
+	}
+	close(LOGF);
+}
+
+sub show_result_immediate {
+	my $event_recv_time;
+	my $udev_fork_time;
+	my $line;
+	my @content;
+	my @line_items;
+	my $diff;
+
+	($event_recv_time) = @_;
+
+	print "   event receiving time:  $event_recv_time\n\n";
+
+	open(LOGF, $log_file) || die "Opening file $log_file: $!";
+	@content = <LOGF>;
+	foreach $line ( @content ) {
+		@line_items = split(/,/,$line);
+		print "   device: $line_items[0], action: $line_items[1] \n";
+		print "   forking udev time:     $line_items[-1]";
+		$diff = cmpDate($line_items[-1], $event_recv_time);
+		print "   the delay time is:     $diff s \n\n";
+		if ( $diff > $time_out ) {
+			print "   the delay time is:     $diff \n";
+			print "   udevd doesn't act properly. \n";
+			exit 1;
+		}
+	}
+	close(LOGF);
+}
+
+sub check_exe_time {
+	my @exe_time;
+	my $i = 0;
+	my $line;
+	my @content;
+	my @line_items;
+	my $diff;
+
+	open(LOGF, $log_file) || die "Opening file $log_file: $!";
+	@content = <LOGF>;
+	close(LOGF);
+	foreach $line ( @content ) {
+		@line_items = split(/,/,$line);
+		$exe_time[$i] = $line_items[-1];
+		$i++;
+	}
+	$diff = cmpDate($exe_time[1], $exe_time[0]);
+	if ( $diff < $udev_exe_time ) {
+		print "   there are more than one udev instance for a single device at the same time. \n";
+		exit 1;
+	} else {
+		print "   there is just one udev instance for a single device at the same time. \n";
+	}
+}
+
+# test case functions
+sub run_no_seq_test {
+	print "Test case name:     no sequence number test\n";
+	print "Test case purpose:  check whether udevd forks udev immediately when environment variable SEQNUM is null.\n";
+	print "Test expected visible results: \n";
+	print "   the delay time between event receiving and forking udev for udevd should be negligible, \n";
+	print "   that is, udev should be forked at once. please notice the following time...\n\n";
+
+	# local variables
+	my $time;
+
+	#
+	# add devices event test
+	#
+	kill_daemon();
+
+	# check if devices /sys/block/hda, loop1, loop2 exist
+	check_sysfs_device_exist("$sysfs/block/hda", "$sysfs/block/loop1", "$sysfs/block/loop2");
+
+	# log current system date/time
+	$time = getDate();
+
+	# fork udevd
+	udevsend(-1, "/block/hda", "add", "block");
+
+	# check if execution is successful in time
+	sleep 1;
+	show_result_immediate($time);
+	print "   fork udev (add device) at once successfully.\n\n";
+
+	#
+	# remove devices event test
+	#
+	system("rm -f $log_file");
+
+	# log current system date/time
+	$time = getDate();
+
+	# fork udevd
+	udevsend(-1, "/block/hda", "remove", "block");
+
+	# check if execution is successful in time
+	sleep 1;
+	show_result_immediate($time);
+	print "   fork udev (remove device) at once successfully.\n\n";
+	print "this case is ok\n\n";
+}
+
+sub run_normal_seq_test {
+	print "Test case name:    normal sequence number stress test\n";
+	print "Test case purpose: check whether udevd can fork massive udev instances for \n";
+	print "                   massive sequential events successfully. \n";
+	print "Test expected visible results: \n";
+	print "   Populate all the devices in directory $sysfs/block, fork udved to send add/remove \n";
+	print "   event to udev for each device. \n";
+	print "   We can see the delay time for each device should be negligible. \n\n";
+
+	# local variables
+	my @file_list;
+	my $file;
+	my $seq = 0;
+	my $time;
+	my $ret_seq;
+
+	# prepare
+	kill_daemon();
+	@file_list = glob "$sysfs/block/*";
+
+	# log current system date/time for device add events
+	$time = getDate();
+
+	#
+	# add devices event test
+	#
+	print "add device events test: \n";
+	foreach $file (@file_list) {
+		udevsend($seq, substr($file, length($sysfs), length($file)-length($sysfs)), "add", "block");
+		# check if execution is successful
+		if ($? == 0) {
+			$seq++;
+		} else {
+			print "add event: error\n\n";
+			exit 1;
+		}
+	}
+
+	# we'd better wait the udev to create all the device for a few seconds
+	print "   wait for udevd processing about $time_out s... \n\n";
+	sleep $time_out;
+
+	$ret_seq = check_count_and_time($time);
+	if ( $ret_seq != $seq ) {
+		print "   add event: failed. some device-adding events fail to execute.\n\n";
+		exit 1;
+	} else {
+		print "   $seq pieces of device-adding events have executed successfully.\n\n";
+	}
+
+	# log current system date/time for device remove events
+	$time = getDate();
+
+	#
+	# remove devices event test
+	#
+	print "remove device events test: \n";
+	kill_daemon();
+	@file_list = glob "$sysfs/block/*"; 
+	$seq = 0;
+	foreach $file (@file_list) {
+		udevsend($seq, substr($file, length($sysfs), length($file)-length($sysfs)), "remove", "block");
+		# check if execution is successful
+		if ($? == 0) {
+			$seq++;
+		} else {
+			print "remove event: error\n\n";
+			exit 1;
+		}
+	}
+
+	# we'd better wait the udev to create all the device for a few seconds
+	print "   waiting for udev removing devices (about $time_out s)...\n";
+	sleep $time_out;
+
+	# show results
+	$ret_seq = check_count_and_time($time);
+	if ( $ret_seq != $seq ) {
+		print "   remove event: failed. some device-removing events fail to execute.\n\n";
+		exit 1;
+	} else {
+		print "   $seq pieces of device-removing events have executed successfully.\n\n";
+		print "this case is ok.\n\n";
+	}
+}
+
+sub run_random_seq_test {
+	print "Test case name:    random sequence number test case,\n";
+	print "Test case purpose: check whether udevd can order the events with random sequence number \n";
+	print "                   and fork udev correctly. \n";
+	print "Test expected visible results: \n";
+	print "   We have disordered the events sent to udevd, if udevd can order them correctly, the devices' \n";
+	print "   add/remove sequence should be hda, loop1, loop2. \n\n";
+
+	# local variables
+	my $time;
+
+	# check if devices /sys/block/hda, loop1, loop2 exist
+	check_sysfs_device_exist("$sysfs/block/hda", "$sysfs/block/loop1", "$sysfs/block/loop2");
+
+	#
+	# add device events test
+	#
+	print "add device events test: \n";
+	kill_daemon();
+
+	# log current system date/time for device remove events
+	$time = getDate();
+
+	# parameters: 1 sequence number, 2 device, 3 action, 4 subsystem
+	udevsend(3, "/block/loop2", "add", "block");
+	udevsend(1, "/block/hda", "add", "block");
+	udevsend(2, "/block/loop1", "add", "block");
+	print "   wait for udevd processing about $time_out s... \n\n";
+	sleep $time_out+1;
+	show_result_tm_out($time);
+
+	#
+	# remove device events test
+	#
+	print "\nremove device events test: \n";
+	kill_daemon();
+
+	# log current system date/time for device remove events
+	$time = getDate();
+
+	# fork udevd
+	udevsend(3, "/block/loop2", "remove", "block");
+	udevsend(2, "/block/loop1", "remove", "block");
+	udevsend(1, "/block/hda", "remove", "block");
+
+	# show results
+	print "   wait for udevd processing about $time_out s... \n\n";
+	sleep $time_out+1;
+	show_result_tm_out($time);
+	print "this case is ok.\n\n";
+}
+
+sub run_expected_seq_test { 
+	print "Test case name:    expected sequence number test \n";
+	print "Test case purpose: check whether udevd fork udev immediately when the incoming event\n";
+	print "                   is exactly the expected event sequence number.\n";
+	print "Test expected visible results:\n";
+	print "   first, udevd disposes disorder events(sequence number is 3,1,2,5,4,6),\n";
+	print "   thus after disposed the expected event number for udevd is 7, when incoming event is 7, udevd\n";
+	print "   should fork udev immediately, the delay time should be negligible. \n";
+	print "   where: event 7 is (add device /block/loop2) \n\n";
+
+	# local variables
+	my $time;
+
+	# check if devices /sys/block/hda, loop1, loop2 exist
+	check_sysfs_device_exist("$sysfs/block/hda", "$sysfs/block/loop1", "$sysfs/block/loop2");
+
+	# prepare
+	kill_daemon();
+
+	# parameters: 1 sequence number, 2 device, 3 action, 4 subsystem
+	udevsend(3, "/block/loop2", "add", "block");
+	udevsend(1, "/block/hda", "add", "block");
+	udevsend(2, "/block/loop1", "add", "block");
+	udevsend(5, "/block/loop1", "remove", "block");
+	udevsend(4, "/block/hda", "remove", "block");
+	udevsend(6, "/block/loop2", "remove", "block");
+
+	print "   wait for udevd timing out for disorder events (about $time_out s) \n\n";
+	sleep $time_out+1;
+	system("rm -f $log_file");
+
+	# log current system date/time for device remove events
+	$time = getDate();
+
+	# show results
+	udevsend(7, "/block/loop2", "add", "block");
+	sleep 1;
+	print "   event sequence number: 7 \n";
+	show_result_immediate($time);
+
+	print "this case is ok.\n\n";
+}
+
+sub run_single_instance_test { 
+	print "Test case name:    single instance running for a single device test \n";
+	print "Test case purpose: check whether udevd only fork one udev instance for a single\n";
+	print "                   device at the same time. For each event a udev instance is \n";
+	print "                   executed in the background. All further events for the same \n";
+	print "                   device are delayed until the execution is finished. This way \n";
+	print "                   there will never be more than one instance running for a single \n";
+	print "                   device at the same time.\n";
+	print "Test expected visible results:\n";
+	print "   In this test we amplify the execution time of udev (about 5 seconds), first, \n";
+	print "   we send a add event for device /block/hda, and then we send a remove event, so the \n";
+	print "   execution of remove event should be delayed until add is finished. \n\n";
+
+	# local variables
+	my $time;
+
+	# prepare
+	kill_daemon();
+
+	# check if device exists
+	check_sysfs_device_exist("$sysfs/block/hda");
+
+	# log current system date/time
+	$time = getDate();
+
+	# fork udved
+	udevsend(-1, "/block/hda", "add", "block", $udev_bin2);
+	udevsend(-1, "/block/hda", "remove", "block", $udev_bin2);
+
+	# show results
+	print "   wait for udevd processing about $udev_exe_time s... \n\n";
+	sleep $udev_exe_time+1;
+	show_result_immediate($time);
+	check_exe_time();
+	print "this case is ok\n\n";
+}
+
+sub run_same_events_test { 
+	print "Test case name:    event sequence number overlap test \n";
+	print "Test case purpose: check whether udevd doesn't fork udev untill time out\n";
+	print "                   when encountering a event with sequence number same as the pevious event. \n";
+	print "Test expected visible results:\n";
+	print "   event ( add device /block/hda ) should be no delay, \n";
+	print "   event ( add device /block/loop1 ) should be delayed for $time_out s than its previous \n";
+	print "   event ( remove device /block/hda ) \n\n";
+
+	# local variables
+	my $time;
+
+	# prepare
+	kill_daemon();
+
+	# check if device exist
+	check_sysfs_device_exist("$sysfs/block/hda", "$sysfs/block/loop1");
+
+	# fork udevd
+	udevsend(0, "/block/hda", "add", "block");
+
+	# log current system date/time
+	sleep 1;
+	$time = getDate();
+	system("rm -f $log_file");
+
+	# fork udevd
+	udevsend(1, "/block/hda", "remove", "block");
+	udevsend(1, "/block/loop1", "add", "block");
+
+	# show results
+	print "   wait for udevd processing about $time_out s... \n\n";
+	sleep $time_out+1;
+	show_result($time);
+	print "this case is ok\n\n";
+}
+
+sub run_missing_seq_test {
+	print "Test case name:    missing sequence number test \n";
+	print "Test case purpose: check whether udevd doesn't fork udev untill time out\n";
+	print "                   when certain event sequence number is missing.\n";
+	print "Test expected visible results:\n";
+	print "   the delay time for event(add device /block/hda) should be about $time_out s.\n\n";
+
+	# local variables
+	my $time;
+
+	# prepare
+	kill_daemon();
+
+	# check if device exist
+	check_sysfs_device_exist("$sysfs/block/hda", "$sysfs/block/loop1");
+
+	# fork udevd
+	udevsend(0, "/block/loop1", "add", "block");
+	udevsend(1, "/block/loop1", "remove", "block");
+	sleep 1;
+
+	# log current system date/time
+	$time = getDate();
+	system("rm -f $log_file");
+
+	# fork udevd
+	udevsend(3, "/block/hda", "add", "block");
+
+	# show results
+	print "   wait for udevd processing about $time_out s... \n\n";
+	sleep $time_out+1;
+	show_result($time);
+	print "this case is ok\n\n";
+}
+
+sub run_all_cases_test { 
+	run_no_seq_test();
+	run_normal_seq_test();
+	run_random_seq_test();
+	run_missing_seq_test();
+	run_expected_seq_test();
+	run_same_events_test();
+	run_single_instance_test();
+}
+
+# main program
+if ($ARGV[0]) {
+	$test_case = $ARGV[0];
+
+	if ($test_case == 1) {
+		run_no_seq_test();
+	} elsif ($test_case == 2) {
+		run_normal_seq_test();
+	} elsif ($test_case == 3) {
+		run_random_seq_test();
+	} elsif ($test_case == 4) {
+		run_missing_seq_test();
+	} elsif ($test_case == 5) {
+		run_expected_seq_test();
+	} elsif ($test_case == 6) {
+		run_single_instance_test();
+	} elsif ($test_case == 7) {
+		run_same_events_test();
+	} else {
+		run_all_cases_test();
+	}
+} else {
+	# echo usage
+	print "command format: perl udevd-test.pl <case number>\n";
+	print "   test case:\n";
+	print "           1: no event sequence number\n";
+	print "           2: sequential event sequence number\n";
+	print "           3: random event sequence number\n";
+	print "           4: missing event sequence number\n";
+	print "           5: the incoming event sequence number is right the expected sequence number\n";
+	print "           6: single udev instance on a single device at the same time\n";
+	print "           7: test event sequence number overlap\n";
+	print "           9: all the cases\n\n";
+}
diff -Nru a/udevd.c b/udevd.c
--- a/udevd.c	Tue Apr 13 15:21:43 2004
+++ b/udevd.c	Tue Apr 13 15:21:43 2004
@@ -60,6 +60,7 @@
 static void msg_queue_manager(void);
 static void user_sighandler(void);
 static void reap_kids(void);
+char *udev_bin;
 
 #ifdef LOG
 unsigned char logname[LOGNAME_SIZE];
@@ -146,7 +147,7 @@
 	switch (pid) {
 	case 0:
 		/* child */
-		execle(UDEV_BIN, "udev", msg->subsystem, NULL, env);
+		execle(udev_bin, "udev", msg->subsystem, NULL, env);
 		dbg("exec of child failed");
 		exit(1);
 		break;
@@ -457,6 +458,13 @@
 
 	/* enable receiving of the sender credentials */
 	setsockopt(ssock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
+
+	/* possible override of udev binary, used for testing */
+	udev_bin = getenv("UDEV_BIN");
+	if (udev_bin != NULL)
+		dbg("udev binary is set to '%s'", udev_bin);
+	else
+		udev_bin = UDEV_BIN;
 
 	FD_ZERO(&readfds);
 	FD_SET(ssock, &readfds);