When I start runlevel 2 I get 600 permissions, but when I switch to runlevel 1
/dev/null gets proper 666 permissions. So I restarted to get 600 again, and then
started stopping one by one service to see when does the change happen:
for file in `ls -1 /etc/rc1.d/*|grep -v README|grep -v S90single`;
do echo $file >> /tmp/null.log;
ls -l /dev/null >> /tmp/null.log;
sh $file stop;
ls -l /dev/null >> /tmp/null.log;
echo "___________" >> /tmp/null.log ;
done
File /tmp/null.log got this content:
K01gdm
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K01kdm
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K01usplash
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K09apache2
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K11anacron
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K11atd
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K11cron
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K19cupsys
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K19hplip
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K19samba
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20acpi-support
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20apmd
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20apport
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20avahi-daemon
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20console-setup
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20dbus
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20hotkey-setup
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20kde-guidance
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20keyboard-setup
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20makedev
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20networking
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20nvidia-kernel
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20powernowd
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20procps.sh
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20rsync
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20ssh
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20udev
crw------- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K20vsftpd
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K21acpid
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K21mysql
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K22mysql-ndb
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K23mysql-ndb-mgm
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K30killprocs
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K30squid
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K74bluetooth
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K79nfs-common
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K80nfs-kernel-server
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K81portmap
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K89klogd
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
K90sysklogd
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 2007-04-15 13:49 /dev/null
___________
Ok, then I restarted, and went to single-user mode, and started starting all
of the services from runlevel 2:
for file in /etc/rc2.d/S*;
do echo $file >> /tmp/null-single.log;
ls -l /dev/null >> /tmp/null-single.log;
sh $file start;
ls -l /dev/null >> /tmp/null-single.log;
done
File /tmp/null-single.log got:
S20makedev
crw-rw-rw- 1 root root 1, 3 Apr 15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 Apr 15 13:49 /dev/null
S20procps.sh
crw-rw-rw- 1 root root 1, 3 Apr 15 13:49 /dev/null
crw-rw-rw- 1 root root 1, 3 Apr 15 13:49 /dev/null
S20udev
crw-rw-rw- 1 root root 1, 3 Apr 15 13:49 /dev/null
crw------- 1 root root 1, 3 Apr 15 13:49 /dev/null
S99rmnologin
crw------- 1 root root 1, 3 Apr 15 13:49 /dev/null
crw------- 1 root root 1, 3 Apr 15 13:49 /dev/null
It's udev script again. Ok, then I tried debugging it:
#!/bin/sh -e
# init script for udev
# Edited by turncoat for debugging
# Check the package is still installed
[ -x /sbin/udevd ] || exit 0
# Get LSB functions
echo 1: `ls -l /dev/null` >> /tmp/null-edit.log;
. /lib/lsb/init-functions
echo 2: `ls -l /dev/null` >> /tmp/null-edit.log;
. /etc/default/rcS
case "$1" in
start)
# We need the uevent support introduced in 2.6.15, bail out if
we
# don't have it and fall back to a static /dev
if [ ! -f /sys/class/mem/null/uevent ]; then
if mountpoint -q /dev; then
# uh-oh, initramfs made some kind of /dev, get rid of it
umount -l /dev/.static/dev
umount -l /dev
fi
exit 1
fi
echo 3: `ls -l /dev/null` >> /tmp/null-edit.log;
if ! mountpoint -q /dev; then
# initramfs didn't mount /dev, so we'll need to do that
mount -n --bind /dev /etc/udev
mount -n -t tmpfs -o mode=0755 udev /dev
mkdir -m 0700 -p /dev/.static/dev
mount -n --move /etc/udev /dev/.static/dev
fi
echo 4: `ls -l /dev/null` >> /tmp/null-edit.log;
# Copy over default device tree
cp -a -f /lib/udev/devices/* /dev
# It's all over netlink now
if [ -e /proc/sys/kernel/hotplug ]; then
echo "" > /proc/sys/kernel/hotplug
fi
echo 5: `ls -l /dev/null` >> /tmp/null-edit.log;
# Start udevd
log_begin_msg "Starting kernel event manager..."
if start-stop-daemon --start --quiet --exec /sbin/udevd --
--daemon; then
log_end_msg 0
else
log_end_msg $?
fi
echo 6: `ls -l /dev/null` >> /tmp/null-edit.log;
# This next bit can take a while
if type usplash_write >/dev/null 2>&1; then
usplash_write "TIMEOUT 360" ||:
trap "usplash_write 'TIMEOUT 15' ||:" 0
fi
echo 7: `ls -l /dev/null` >> /tmp/null-edit.log;
# Log things that udevtrigger does (won't work on seb's machine)
if [ -x /usr/sbin/udevmonitor ]; then
/usr/sbin/udevmonitor -e >/dev/.udev.log &
UDEV_MONITOR_PID=$!
fi
echo 8: `ls -l /dev/null` >> /tmp/null-edit.log;
# Fix permissions and missing symlinks/programs for devices
made in
# initramfs, and catch up on everything we missed
log_begin_msg "Loading hardware drivers..."
/sbin/udevtrigger
echo 8-1: `ls -l /dev/null` >> /tmp/null-edit.log;
if /sbin/udevsettle; then
log_end_msg 0
echo 8-1-if: `ls -l /dev/null` >> /tmp/null-edit.log;
else
log_end_msg $?
echo 8-1-else: `ls -l /dev/null` >> /tmp/null-edit.log;
fi
echo 9: `ls -l /dev/null` >> /tmp/null-edit.log;
# Kill the udevmonitor again
if [ -n "$UDEV_MONITOR_PID" ]; then
kill $UDEV_MONITOR_PID
fi
echo 10: `ls -l /dev/null` >> /tmp/null-edit.log;
;;
stop)
log_begin_msg "Stopping kernel event manager..."
echo stop1: `ls -l /dev/null` >> /tmp/null-edit.log;
if start-stop-daemon --stop --quiet --oknodo --exec
/sbin/udevd; then
echo stop-if: `ls -l /dev/null` >> /tmp/null-edit.log;
log_end_msg 0
else
echo stop-else: `ls -l /dev/null` >> /tmp/null-edit.log;
log_end_msg $?
fi
echo stop-fi: `ls -l /dev/null` >> /tmp/null-edit.log;
umount -l /dev/.static/dev
echo stop-static: `ls -l /dev/null` >> /tmp/null-edit.log;
umount -l /dev
echo stop-dev: `ls -l /dev/null` >> /tmp/null-edit.log;
;;
restart)
cp -au /lib/udev/devices/* /dev
log_begin_msg "Loading additional hardware drivers..."
/sbin/udevtrigger
if /sbin/udevsettle; then
log_end_msg 0
else
log_end_msg $?
fi
;;
reload|force-reload)
log_begin_msg "Reloading kernel event manager..."
if start-stop-daemon --stop --signal 1 --exec /sbin/udevd; then
log_end_msg 0
else
log_end_msg $?
fi
;;
*)
echo "Usage: /etc/init.d/udev
{start|stop|restart|reload|force-reload}"
exit 1
;;
esac
exit 0
After restarting and going to runlevel 2, file /tmp/null-edit.log had:
1: crw-rw---- 1 root root 1, 3 Jul 10 2007 /dev/null
2: crw-rw---- 1 root root 1, 3 Jul 10 2007 /dev/null
3: crw-rw---- 1 root root 1, 3 Jul 10 2007 /dev/null
4: crw-rw---- 1 root root 1, 3 Jul 10 2007 /dev/null
5: crw------- 1 root root 1, 3 Apr 15 13:49 /dev/null
6: crw------- 1 root root 1, 3 Apr 15 13:49 /dev/null
7: crw------- 1 root root 1, 3 Apr 15 13:49 /dev/null
8: crw------- 1 root root 1, 3 Apr 15 13:49 /dev/null
8-1: crw------- 1 root root 1, 3 Apr 15 13:49 /dev/null
8-1-if: crw-rw-rw- 1 root root 1, 3 Apr 15 13:49 /dev/null
9: crw-rw-rw- 1 root root 1, 3 Apr 15 13:49 /dev/null
10: crw-rw-rw- 1 root root 1, 3 Apr 15 13:49 /dev/null
So, file /dev/null get created with 660 (?) permissions, then got changed to 600
after the line
cp -a -f /lib/udev/devices/* /dev
( the file /lib/udev/devices/null has 600 permissions )
And then it got fixed to 666 by the /sbin/udevsettle program.
The strangest thing happened - the /dev/null got right permissions.
After I changed back udev script to it's original, I got 600 on /dev/null again!
I suppose that it's some race condition problem with udev and udevsettle
program,
since it work right when I put the echo between running
/sbin/udevtrigger and /sbin/udevsettle (or something similar).
My workaround is to put 666 to /lib/udev/devices/null , so when it get's copied
to /dev/null it has the right permissions, weather or not the udevsettle do it's
job or not. But this is only workaround for /dev/null - who knows what other
problems will occur if my suspicions about race condition are right.
If you need any more information or testing from me, I will be happy to try
something more.
I'll keep this machine in this state for one more week, and then I will
reinstall it.
Cheers!
Marko
--
Permissions changed in /dev/null in every boot
https://bugs.launchpad.net/bugs/53040
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