chroot hack

busyroot.sh

#!/bin/sh

CHROOT=${1:-"myroot"}
ARCH=${2:-"armv5l"}

test -n "$UNSHARE" || {
  export UNSHARE="unshare --fork --pid --mount"
  exec $UNSHARE $0 $CHROOT
}

mydir() {
  test -d $1 || mkdir -p $1
}

mountem() {
#############################
mydir $CHROOT
export CHROOT=$(cd $CHROOT; pwd)

mydir $CHROOT/bin
./busybox-$ARCH --install $CHROOT/bin

mydir $CHROOT/proc
mount -v -t proc proc -o rw,nosuid,nodev,noexec,relatime $CHROOT/proc
#############################
}

mountem
chroot $CHROOT

echo
mount | grep $CHROOT | awk '{print $3}' | while read mntpoint;
	do umount -v $mntpoint; done;

chsys.sh

#!/bin/sh

test -n "$UNSHARE" || {
test $(id -u) -eq 0 || { echo "You have to be root!"; exit 1; }
basename=${0##*/}

#trap '' INT QUIT TERM EXIT

export CHROOT=$(cd $1; pwd); shift
test -d "$CHROOT" || { echo Directory $CHROOT does not exist.; exit 1; }
export COMMAND=${*:-'/bin/su -'}

# /etc/resolv.conf, /etc/hosts, /etc/fstab, /etc/passwd,
# /etc/group, /etc/shadow, /etc/ld.so.conf, /etc/scsi_id.config

cpfromsys() { F=$1; cp $F $CHROOT/$F; }
F=$CHROOT/etc/sysconfig; test -d $F && touch $F/network
cpfromsys /etc/hosts
cpfromsys /etc/resolv.conf

echo "$CHROOT" | grep -q "i386" && export SETARCH="setarch i386"
UNSHARE="unshare --ipc --mount --uts --fork --pid"
export UNSHARE
exec sh $0

} && {

PS1='\$ '
exec $SETARCH $UNSHARE sh -c "
	mount -v -t devpts -o newinstance devpts $CHROOT/dev/pts;
	mount -v -t tmpfs -o rw,nosuid,nodev tmpfs $CHROOT/dev/shm;
	mount -v -t sysfs -o rw,nosuid,nodev,noexec,relatime sys $CHROOT/sys;
	mount -v -t proc proc $CHROOT/proc;
	ln -nsf pts/ptmx $CHROOT/dev/ptmx
	chroot $CHROOT env -i \
	  SHELL=$SHELL \
	  HOME=$HOME \
	  TERM=$TERM \
	  PS1=\"chsys:${CHROOT##*/}$PS1\" \
	  DISPLAY=$DISPLAY \
	  PATH=/usr/sbin:/usr/bin:/sbin:/bin \
	  CHROOT=$CHROOT \
	    /bin/sh -c \"exec $COMMAND\";
	EXIT=\$?;
	mount | grep $CHROOT | awk '{print \$3}' | while read mntpoint;
	do umount -v \$mntpoint; done;
	exit \$EXIT;
"
}

makedevs.device_table.txt

/dev     d	755	0	0	-	-	-	-	-
/dev/pts d	755	0	0	-	-	-	-	-
/dev/shm d	755	0	0	-	-	-	-	-
/tmp     d	1777	0	0	-	-	-	-	-
/etc     d	755	0	0	-	-	-	-	-
/root    d	750	0	0	-	-	-	-
/bin/busybox	f 4755	0	0	-	-	-	-	-
/etc/shadow	f 600	0	0	-	-	-	-	-
/etc/passwd	f 644	0	0	-	-	-	-	-
#/etc/network/if-up.d d 755 0	0	-	-	-	-	-
#/etc/network/if-pre-up.d d 755	0 0	-	-	-	-	-
#/etc/network/if-down.d d 755	0 0	-	-	-	-	-
#/etc/network/if-post-down.d d 755 0 0	-	-	-	-	-

###/usr/share/udhcpc/default.script f 755 0 0 -	-	-	-	-
# uncomment this to allow starting x as non-root
#/usr/X11R6/bin/Xfbdev f 4755 0 0	-	-	-	-	-

# Normal system devices
# <name>  <type> <mode> <uid> <gid> <major> <minor> <start> <inc> <count>
/dev/mem	c 640 0	0	1	1	0	0	-
/dev/kmem	c 640 0	0	1	2	0	0	-
/dev/null	c 666 0	0	1	3	0	0	-
/dev/zero	c 666 0	0	1	5	0	0	-
/dev/random	c 666 0	0	1	8	0	0	-
/dev/urandom	c 666 0	0	1	9	0	0	-
/dev/ram	b 640	0	0	1	1	0	0	-
/dev/ram	b 640	0	0	1	0	0	1	4
/dev/loop	b 640	0	0	7	0	0	1	2
/dev/rtc	c 640	0	0	10	135	-	-	-
/dev/console	c 666	0	0	5	1	-	-	-
/dev/tty	c 666	0	0	5	0	-	-	-
/dev/tty	c 666	0	0	4	0	0	1	8
/dev/ttyp	c 666	0	0	3	0	0	1	10
/dev/ptyp	c 666 0 0 2 0 0 1 10
/dev/ptmx	c 666	0	0	5	2	-	-	-
/dev/ttyP	c 666	0	0	57	0	0	1	4
/dev/ttyS	c 666	0	0	4	64	0	1	4
/dev/fb		c 640	0	5	29	0	0	32	4
/dev/psaux	c 666	0	0	10	1	0	0	-

# Input stuff
/dev/input	d 755	0	0	-	-	-	-	-
/dev/input/mice	c 640	0	0	13	63	0	0	-
/dev/input/mouse c 660	0	0	13	32	0	1	4
/dev/input/event c 660	0	0	13	64	0	1	4

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