Re: [gentoo-user] Implicit udev dependancy in Gentoo? and workaround.

[William Kenworthy <billk@iinet.net.au>]

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On 25/12/12 11:21, Walter Dnes wrote:
>   I'm asking questions here before filing a bug/reature-request, to make
> sure I have my ducks in a row.  I did a big update a couple of days ago.
> As per the user in...  http://forums.gentoo.org/viewtopic-p-7168984.html
> I too ran into a situation where I couldn't open any xterms because
> /dev/pts was empty.  The solution for that user came in 2 parts...
>
> 1) Add the following line to /etc/fstab
> devpts     /dev/pts      devpts      defaults 0 0
>
> 2) Run "rc-update add udev-mount sysinit" oops... what udev-mount?  I'm
> the troublemaker/malcontent who runs mdev instead of udev.
>
>   I noticed that the temporary solution would be to manually execute
> "mount devpts".  The problem was that it would only last till the next
> reboot, after which the mount needed to be issued again.  I got around
> that by putting "mount devpts" in /etc/local.d/000.start (which file
> must be executable).  It is executed every bootup, solving the problem.
> My questions...
>
> 1) Is this just my system, or has anybody else with mdev run into it?
> If others have the same problem, I'll update the mdev wiki page to
> mention this.
>
> 2) Can someone who uses udev have a look at their "udev-mount" script
> and see if it does any other stuff besides mounting devpts?
>

It does a few other things ... attached it here as its not that long.

BillK



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#!/sbin/runscript
# Copyright 1999-2010 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2

description="mount devtmpfs on /dev"

depend()
{
	provide dev-mount
	keyword -vserver -lxc
}

mount_dev_directory()
{
	local mounted=false fstab=false action=--mount msg=Mounting rc=0

	if ! grep -qs devtmpfs /proc/filesystems; then
		eerror "CONFIG_DEVTMPFS=y is required in your kernel configuration"
		eerror "for this version of udev to run successfully."
		eerror "This requires immediate attention."
		if ! mountinfo -q /dev; then
			mount -n -t tmpfs dev /dev
			busybox mdev -s
			mkdir /dev/pts
		fi
		return 1
	fi

	# Is /dev already a mounted devtmpfs?
	mountinfo -q -f devtmpfs /dev && mounted=true

	# If an entry for /dev exists in fstab it must be a devtmpfs.
	fstabinfo -q -t devtmpfs /dev && fstab=true

	# No options are processed here as they should all be in /etc/fstab
	if $fstab; then
		$mounted && action=--remount && msg=Remounting
		ebegin "$msg /dev according to /etc/fstab"
		fstabinfo $action /dev
		rc=$?
	elif ! $mounted; then
		ebegin "Mounting /dev"
		# Some devices require exec, Bug #92921
		mount -n -t devtmpfs -o "exec,nosuid,mode=0755,size=10M" udev /dev
		rc=$?
	else
		ebegin "Using /dev mounted from kernel"
	fi

	eend $rc
}

seed_dev()
{
	# Seed /dev with some things that we know we need

	# creating /dev/console, /dev/tty and /dev/tty1 to be able to write
	# to $CONSOLE with/without bootsplash before udevd creates it
	[ -c /dev/console ] || mknod -m 600 /dev/console c 5 1
	[ -c /dev/tty1 ] || mknod -m 620 /dev/tty1 c 4 1
	[ -c /dev/tty ] || mknod -m 666 /dev/tty c 5 0

	# udevd will dup its stdin/stdout/stderr to /dev/null
	# and we do not want a file which gets buffered in ram
	[ -c /dev/null ] || mknod -m 666 /dev/null c 1 3

	# so udev can add its start-message to dmesg
	[ -c /dev/kmsg ] || mknod -m 660 /dev/kmsg c 1 11

	# Create problematic directories
	mkdir -p /dev/pts /dev/shm
	return 0
}

start()
{
	mount_dev_directory || return 1

	seed_dev
	return 0
}