#!/bin/sh

proc die {
	echo >&2 @Argv> !2 "$@"
	exit 1
}

proc xmkdir {
	while test -n $1 {
		test -d $1 || mkdir $1 || die "Unable to mkdir $1"
		shift
	}
}

setglobal R = $1

test $[id -u] -eq 0 && die "This script should not be run as root, what if it does rm -rf /?"
test -n $R || die "usage: prepare-chroot.sh <root>"
test -x git || die "This script needs to be executed at git source code's top directory"
if test -x /bin/busybox {
	setglobal BB = '/bin/busybox'
} elif test -x /usr/bin/busybox {
	setglobal BB = '/usr/bin/busybox'
} else {
	die "You need busybox"
}

xmkdir $R "$R/bin" "$R/etc" "$R/lib" "$R/dev"
touch "$R/dev/null"
echo "root:x:0:0:root:/:/bin/sh" > "$R/etc/passwd"
echo "$[id -nu]:x:$[id -u]:$[id -g]::$[pwd]/t:/bin/sh" >> "$R/etc/passwd"
echo "root::0:root" > "$R/etc/group"
echo "$[id -ng]::$[id -g]:$[id -nu]" >> "$R/etc/group"

test -x "$R$BB" || cp $BB "$R/bin/busybox"
for cmd in [sh su ls expr tr basename rm mkdir mv id uname dirname cat true sed diff] {
	ln -f -s /bin/busybox "$R/bin/$cmd"
}

mkdir -p "$R$[pwd]"
rsync --exclude-from t/t1509/excludes -Ha . "$R$[pwd]"
# Fake perl to reduce dependency, t1509 does not use perl, but some
# env might slip through, see test-lib.sh, unset.*PERL_PATH
sed 's|^PERL_PATH=.*|PERL_PATH=/bin/true|' GIT-BUILD-OPTIONS > "$R$[pwd]/GIT-BUILD-OPTIONS"
for cmd in [git $BB]{ 
	ldd $cmd | grep '/' | sed 's,.*\s\(/[^ ]*\).*,\1,' | while read i {
		mkdir -p "$R$[dirname $i]"
		cp $i "$R/$i"
	}
}
cat << """
All is set up in $R, execute t1509 with the following commands:

sudo chroot $R /bin/su - $[id -nu]
IKNOWWHATIAMDOING=YES ./t1509-root-worktree.sh -v -i

When you are done, simply delete $R to clean up
"""