#!/usr/bin/python
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#
# 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/user-"+name, "w") as f:
		print >>f, """[user-{0}]
type=directory
directory={1}
users={0}
profile=user
setup.fstab=user/user-{0}.fstab
""".format(name, chroot)
	with open("/etc/schroot/user/user-"+name+".fstab", "w") as f:
		print >>f, """# <file system> <mount point>   <type>  <options>       <dump>  <pass>
/bin          \t/bin          \tnone  \trw,bind       \t0     \t0
/lib          \t/lib          \tnone  \trw,bind       \t0     \t0
/usr/bin      \t/usr/bin      \tnone  \trw,bind       \t0     \t0
/usr/lib      \t/usr/lib      \tnone  \trw,bind       \t0     \t0
/home/{0}/data\t/data         \tnone  \trw,bind       \t0     \t0
""".replace(' ', '').format(name) # need to remove spaces so schroot does not complain
	
	# 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 >>f, "root:x:0:0:root:/root:/bin/bash"
		print >>f, "{0}:x:{1}:{2}:,,,:/data:/bin/false".format(name, userpw.pw_uid, userpw.pw_gid)
	with open(os.path.join(chroot, "etc", "group"), "w") as f:
		print >>f, "root:x:0:"
		usergrp = grp.getgrgid(userpw.pw_gid)
		print >>f, "{0}:x:{1}:".format(usergrp.gr_name, usergrp.gr_gid)
		if group:
			groupgrp = grp.getgrnam(group)
			assert usergrp.gr_gid != groupgrp.gr_gid
			print >>f, "{0}:x:{1}:{2}".format(groupgrp.gr_name, groupgrp.gr_gid, name)
	
	# 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)