aufs.shlib

#
# Copyright (C) 2005-2011 Junjiro R. Okajima
#
# This program, aufs 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; either version 2 of the License, or
# (at your option) any later version.
#
# 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

# library functions for aufs shell scripts

# path in canonical representation
# note: bash builtin "pwd -P" modies $PWD unexpectedly
SetDir() # var dir
{
	cd "$2"
	eval "$1=\"$(pwd -P)\""
	cd "$OLDPWD"
}

# escape the unprintable characters, mainly for grep-ping /proc/mounts
Esc() # [-e]
{
	sed -r -e '
	s/\\/\\134/g
	s/$/\\012/
	' |
	tr -d '\n' |
	sed -r -e '
	s/ /\\040/g
	s/\t/\\011/g
	s/\r/\\015/g
	s/\\012$//
	' |
	{ test $# -eq 1 &&
	test "$1" = "-e" &&
	sed -r -e 's/\\/\\\\/g' ||
	cat; }
	echo
}

# find a mount-entry by its mount-point
FindMntEnt() # mntpnt
{
	proc_mounts=/proc/self/mounts
	test ! -e $proc_mounts && proc_mounts=/proc/$$/mounts
	test ! -e $proc_mounts && proc_mounts=/proc/mounts
	fgrep \ $(echo "$1" | Esc)\ aufs\  $proc_mounts |
	tail -n 1
}

# current mount options
MntOpts() # mntpnt
{
	FindMntEnt "$1" |
	cut -f4 -d' '
}

########################################

AuDebug() # 1 | 0 [sec]
{
	test $1 -eq 0 && set +x
	aufs_debug=/sys/module/aufs/parameters/debug
	if [ -f $aufs_debug ]
	then
		echo $1 | sudo dd of=$aufs_debug 2> /dev/null
		test $# -eq 2 && sleep $2
	fi
	test $1 -eq 1 && set -x
	true
}

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# mode: text;
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