#!/usr/bin/python3
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#
# Configuration
schsh = "/usr/local/bin/schsh"
group = "schsh"
chroots = "/var/lib/schsh"

# END of Configuration
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#
# DO NOT TOUCH ANYTHING BELOW THIS LINE

import os, sys, subprocess, pwd, grp

if os.getuid() != 0:
	print("Run this a root, please.")
	sys.exit(1)


def setup(name):
	chroot = os.path.join(chroots, name)
	if os.path.exists(chroot):
		raise Exception(chroot+" already exists, please remove it first")
	userpw = pwd.getpwnam(name)
	
	# schroot configuration
	with open("/etc/schroot/chroot.d/schsh-"+name, "w") as f:
		print("""[schsh-{0}]
type=directory
directory={1}
users={0}
profile=schsh
setup.fstab=schsh/{0}.fstab
""".format(name, chroot), file=f)
	with open("/etc/schroot/schsh/"+name+".fstab", "w") as f:
		# no spaces, schroot does not like them
		print("# <file system> <mount point>   <type>  <options>       <dump>  <pass>", file=f)
		# system folders
		for folder in ("/lib", "/lib64", "/usr/bin", "/usr/lib", "/usr/lib64"):
			if os.path.exists(folder):
				print("{0}\t{0}\tnone\trw,bind\t0\t0".format(folder), file=f)
		# user folder
		print("/home/{0}/data\t/data\tnone\trw,bind\t0\t0".format(name), file=f)
	
	# setup the schroot directory
	os.mkdir(chroot)
	for folder in ["etc", "dev", "bin", "usr", "data"]:
		os.mkdir(os.path.join(chroot, folder))
	
	# setup /etc/passwd and /etc/group
	with open(os.path.join(chroot, "etc", "passwd"), "w") as f:
		print("root:x:0:0:root:/root:/bin/bash", file=f)
		print("{0}:x:{1}:{2}:,,,:/data:/bin/false".format(name, userpw.pw_uid, userpw.pw_gid), file=f)
	with open(os.path.join(chroot, "etc", "group"), "w") as f:
		print("root:x:0:", file=f)
		usergrp = grp.getgrgid(userpw.pw_gid)
		print("{0}:x:{1}:".format(usergrp.gr_name, usergrp.gr_gid), file=f)
		if group:
			groupgrp = grp.getgrnam(group)
			assert usergrp.gr_gid != groupgrp.gr_gid
			print("{0}:x:{1}:{2}".format(groupgrp.gr_name, groupgrp.gr_gid, name), file=f)
	
	# user configuration
	if userpw.pw_shell != schsh:
		subprocess.check_output(["usermod", "--shell", schsh, name])
	if group:
		subprocess.check_output(["adduser", name, "schsh"])
	
	# done!

if len(sys.argv) <= 1:
	print("Usage: %s <usernames>" % sys.argv[0])
else:
	for name in sys.argv[1:]:
		print("Setting up",name)
		setup(name)