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dotfiles/bin/linux-chroot.sh
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#!/bin/sh
#------ cli variables -------------------------------------------------------------------------------------------------------------------------------
PATH=$1 # path for new root
SHELL=$2 # shell to use in chroot
#----------------------------------------------------------------------------------------------------------------------------------------------------
#------- Check root func ----------------------------------------------------------------------------------------------------------------------------
check_root() {
if [ $(/usr/bin/id -u) -ne 0 ]; then # cheking root priveleges
printf "** You must be root\n"
exit 1 # exit with exit code 1 error
fi
}
#----------------------------------------------------------------------------------------------------------------------------------------------------
#----------- checking or create dirs ----------------------------------------------------------------------------------------------------------------
check_or_mkdir() {
[ ! -d $PATH/dev ] && mkdir -pv $PATH/dev # if directory not exists then mkdir
[ ! -d $PATH/proc ] && mkdir -pv $PATH/proc # if directory not exists then mkdir
[ ! -d $PATH/sys ] && mkdir -pv $PATH/sys # if directory not exists then mkdir
[ ! -d $PATH/run ] && mkdir -pv $PATH/run # if directory not exists then mkdir
}
#----------------------------------------------------------------------------------------------------------------------------------------------------
#-------- mount virtual filesystems -----------------------------------------------------------------------------------------------------------------
mount_virtual() {
/usr/bin/mount -v --bind /dev $PATH/dev # mount bind devtmpfs to /dev
/usr/bin/mount -vt devpts devpts -o gid=5,mode=0620 $PATH/dev/pts # mount devpts to /dev/pts
/usr/bin/mount -vt proc proc $PATH/proc # mount procfs to /proc
/usr/bin/mount -vt sysfs sysfs $PATH/sys # mount sysfs to /sys
/usr/bin/mount -vt tmpfs tmpfs $PATH/run # mount tmpfs to /run
if [ -h $PATH/dev/shm ]; then # check
/usr/bin/install -v -d -m 1777 $PATH$(/usr/bin/realpath /dev/shm) # install directories
else
/usr/bin/mount -vt tmpfs -o nosuid,nodev tmpfs $PATH/dev/shm # mount tmpfs to /dev/shm
fi
/usr/bin/cp -v /etc/resolv.conf $PATH/etc/resolv.conf # copy resolv.conf file to chroot
}
#----------------------------------------------------------------------------------------------------------------------------------------------------
#------ umount virtual filesystems ------------------------------------------------------------------------------------------------------------------
umount_virtual() {
/usr/bin/mountpoint -q $PATH/dev/shm && /usr/bin/umount $PATH/dev/shm # umount /dev/shm
/usr/bin/umount $PATH/dev/pts # umount /dev/pts
/usr/bin/umount $PATH/{sys,proc,run,dev} # umount /sys,/proc,/run,/dev
}
#----------------------------------------------------------------------------------------------------------------------------------------------------
#------ get shell path func -------------------------------------------------------------------------------------------------------------------------
get_shell() {
if [[ "$SHELL" != "" ]]; then # if shell is not empty
echo $SHELL # return shell
fi
echo "/bin/sh" # if shell is empty return /bin/sh
}
#----------------------------------------------------------------------------------------------------------------------------------------------------
#------- main ---------------------------------------------------------------------------------------------------------------------------------------
check_root # check root priveleges
check_or_mkdir # check directories for mount virtual filesystems in chroot
mount_virtual # mount virtual filesystems to chroot
#---- do chroot in chroot path using shell ----------------------------------------------------------------------------------------------------------
/usr/bin/chroot \
$PATH \
/usr/bin/env -i \
PATH=/bin:/usr/bin:/sbin:/usr/sbin:/usr/local/bin \
$(get_shell)
#----------------------------------------------------------------------------------------------------------------------------------------------------
umount_virtual # umount virtual filesystems from chroot
#----------------------------------------------------------------------------------------------------------------------------------------------------