#!/usr/bin/python3
import argparse, json, logging, os, pwd, subprocess, sys
import common
from stat import *
from subprocess import PIPE

def command_requires_uid(command):
    return command in ['list', 'list-user', 'reset', 'reset-user', 'set', 'set-user']

def validate_environment():
    if not os.path.exists('/sys/fs/cgroup/cgroup.controllers'):
        common.fatal_error("cgroups is not v2 on this machine")
    if os.getuid() != 0:
        common.fatal_error("this program must be run as root")
    common.ls_ok()
    if not os.path.isfile('/etc/systemd/system.control/user.slice.d/50-IOAccounting.conf'):
        logging.debug('Activate accounting')
        run_program(['systemctl', 'set-property', 'user.slice', 'IOAccounting=yes', 'MemoryAccounting=yes', 'TasksAccounting=yes'])
        systemctl_daemon_reload()
    
def init_pgm():
    common.init_logging()
    parser = argparse.ArgumentParser(prog="lscgctl",
                                     description='LiteSpeed cgroups Control Program')
    parser.add_argument("command", type=str, help="The cgroups command", 
                        choices=['list', 'list-all', 'list-user', 'reset', 'reset-all', 'reset-user', 'set', 'set-all', 'set-user', 'version'])
    parser.add_argument("uid", type=str, nargs='*', default=None, help="uid or user name for -user commands")
    parser.add_argument("--cpu", type=str, help="limit CPU access.  Specify a percentage of a complete core, 100 is 1 complete core.  Default is no limit (-1).")
    parser.add_argument("--io", type=str, help="limit I/O access.  Specify in bytes/sec.  Default is no limit (-1).")
    parser.add_argument("--iops", type=str, help="limit I/O access.  Specify in IOs per second.  Default is no limit (-1).")
    parser.add_argument('-l', '--log', type=int, help='set logging level, 10=Debug, 20=Info, 30=Warning, 40=Error.  Default is Info')
    parser.add_argument("--mem", type=str, help="limit virtual memory access.  Specify in bytes.  Default is no limit (-1).")
    parser.add_argument('-q', '--quiet', action='store_true', help='turns off all logging and only outputs what is requested.')
    parser.add_argument("--tasks", type=str, help="limit number of tasks.  Specify a maximum count of tasks that can be started.")
    args = parser.parse_args()
    if not args.quiet or args.log != None:
        if args.log != None:
            logging.getLogger().setLevel(args.log)
        else:
            logging.getLogger().setLevel(logging.INFO)
        logging.debug("Entering lscgctl")

    validate_environment()
    command = args.command
    if command_requires_uid(command):
        if args.uid == None:
            common.fatal_error("You must specify a user for the %s command" % command)
        users = common.get_users(args.uid)
    else:
        users = None
    if command == 'version':
        logging.info("Version: %s" % common.VERSION)
        if args.quiet:
            print(common.VERSION)
        sys.exit(0)
    if (command.startswith('set')) and (args.cpu == None and args.io == None and args.iops == None and args.mem == None and args.tasks == None):
        common.fatal_error("You specified command: %s and no qualifier to set with it" % command)
    return args, users

def read_stat(file, pos):
    try:
        f = open(file, 'r')
    except Exception as err:
        common.fatal_error('Error opening %s: %s' % (file, err))
    line = f.readline()
    pieces = line.split(' ')
    f.close()
    return pieces[pos]

def run_program(args, fail_reason = ""):
    logging.debug('run: ' + str(args))
    result = subprocess.run(args, stdout=PIPE, stderr=PIPE)
    if fail_reason != "" and result.returncode == 0:
        common.fatal_error('Expected: ' + args[0] + ' to fail: ' + fail_reason)
    if fail_reason == "" and result.returncode != 0:
        common.fatal_error('Error in running: ' + args[0] + ' errors: ' + result.stdout.decode('utf-8') + ' ' + result.stderr.decode('utf-8'))
    return result.stdout.decode('utf-8')

def user_to_file(user):
    return 'user-%s.slice' % user.pw_uid

def user_to_filename(user):
    return '/sys/fs/cgroup/user.slice/%s' % user_to_file(user)

def systemctl_show(user):
    return run_program(['systemctl', 'show', user_to_file(user)])

def systemctl_daemon_reload():
    logging.debug("Do daemon-reload")
    run_program(['systemctl', 'daemon-reload'])

def get_systemctl_item(result, item):
    start = result.find(item)
    if start == -1:
        logging.debug('%s not found in systemctl output' % item)
        return ""
    eol = result[start:].find('\n')
    if eol == -1:
        logging.debug('new line not found in search after finding %s' % item)
        eol = len(result[start:])
    equals = result[start:start+eol].find('=')
    if equals == -1 or equals > eol:
        logging.debug('equals not found in systemctl output search for %s: %s' % (item, result[start:start+eol]))
        return ""
    value = result[start+equals+1:start+eol]
    if value == 'infinity':
        return ''
    logging.debug('systemctl show for ' + item + ':' + value)
    return value
    
def get_systemctl_dev_num(result, item):
    val = get_systemctl_item(result, item)
    space = val.find(' ')
    if space == -1:
        return ''
    logging.debug('result %s: %s, val: %s' % (item, val, val[space+1:]))
    return common.str_num_values(val[space+1:])

def get_systemctl_num(result, item):
    val = get_systemctl_item(result, item)
    logging.debug('result %s: %s' % (item, val))
    return common.str_num_values(val)

def get_systemctl_cpu(result):
    val = get_systemctl_item(result, 'CPUQuotaPerSecUSec')
    if val == 'infinity' or val == 'max' or val == '':
        return ''
    ms = val.find('ms')
    logging.debug('cpu val:' + val + ' ms: %d' % ms)
    if ms > 0:
        percent = int(val[:ms]) / 10
        if percent == 0:
            return '0.%d' % int(val[:ms])
        return '%d' % percent
    s = val.find('s')
    if s > 0:
        return '%d' % int((float(val[:s]) * 100)) # A bug in systemd cgroups
    return '%f' % float(val) / 10000

def list_user(user, dict):
    systemctl_results = systemctl_show(user)
    subdict = {}
    subdict['name'] = user.pw_name
    subdict['cpu'] = get_systemctl_cpu(systemctl_results)
    subdict['io'] = get_systemctl_dev_num(systemctl_results, 'IOReadBandwidthMax')
    subdict['iops'] = get_systemctl_dev_num(systemctl_results, 'IOReadIOPSMax')
    subdict['mem'] = get_systemctl_num(systemctl_results, "MemoryMax")
    subdict['tasks'] = get_systemctl_num(systemctl_results, 'TasksMax')
    logging.debug("uid[" + str(user.pw_uid) + ']: ' + str(subdict))
    dict[user.pw_uid] = subdict
    
def command_list(users):
    dict = {}
    if users != None:
        for user in users:
            list_user(user, dict)
    else:
        users = pwd.getpwall()
        min_uid = common.get_min_uid()
        for listuser in users:
            if listuser.pw_uid >= min_uid and listuser.pw_name != 'nobody':
                list_user(listuser, dict)
    print(json.dumps(dict, indent=4))
    return 0

def set_properties(user, properties):
    pgm_parms = ['systemctl', 'set-property', user_to_file(user)]
    pgm_parms.extend(properties)
    return run_program(pgm_parms)

def set_device_parm(args, option, properties):
    devices = common.get_devices()[0]
    if option == common.OPTION_IO:
        title_read = 'IOReadBandwidthMax'
        title_write = 'IOWriteBandwidthMax'
        val = common.int_num_values(args.io)
    else:
        title_read = 'IOReadIOPSMax'
        title_write = 'IOWriteIOPSMax'
        val = common.int_num_values(args.iops)
    for device in devices:
        if val == -1:
            properties.append('%s=' % title_read)
            properties.append('%s=' % title_write)
            break
        else:
            properties.append('%s=%s %d' % (title_read, device, val))
            properties.append('%s=%s %d' % (title_write, device, val))
    return 0

def set_no_device_parm(args, option, properties):
    if option == common.OPTION_CPU:
        title = 'CPUQuota'
        val = common.int_num_values(args.cpu)
        format_set = '%s=%d%%'
    elif option == common.OPTION_MEM:
        title = 'MemoryMax'
        val = common.int_num_values(args.mem)
        format_set = '%s=%d'
    else:
        title = 'TasksMax'
        val = common.int_num_values(args.tasks)
        format_set = '%s=%d'
    if val == -1:
        properties.append('%s=' % title)
    else:
        properties.append(format_set % (title, val))
    if option == common.OPTION_MEM:
        properties.append('MemoryHigh=')

    
def reset_user(args, user, reload):
    args.cpu = '-1'
    args.io = '-1'
    args.iops = '-1';
    args.mem = '-1'
    args.tasks = '-1'
    return set_user(args, user, reload)

def command_reset(args, users):
    if args.command == 'reset' or args.command == 'reset-user':
        for user in users:
            reset_user(args, user, True)
    else:
        users = pwd.getpwall()
        min_uid = common.get_min_uid()
        need_reload = False
        for listuser in users:
            if listuser.pw_uid >= min_uid:
                need_reload = True
                reset_user(args, listuser)
        if need_reload:
            systemctl_daemon_reload()
    if not args.quiet:
        logging.info("Reset successful")
    return 0

def set_user(args, users, reload):
    properties = []
    if args.cpu != None:
        set_no_device_parm(args, common.OPTION_CPU, properties)
    if args.io != None:
        set_device_parm(args, common.OPTION_IO, properties)
    if args.iops != None:
        set_device_parm(args, common.OPTION_IOPS, properties)
    if args.mem != None:
        set_no_device_parm(args, common.OPTION_MEM, properties)
    if args.tasks != None:
        set_no_device_parm(args, common.OPTION_TASKS, properties)
    for user in users:
        set_properties(user, properties)
    if reload:
        systemctl_daemon_reload()
    if not args.quiet:
        return command_list(users)
    return 0

def command_set(args, users):
    if args.command == 'set' or args.command == 'set-user':
        set_user(args, users, True)
    else:
        users = pwd.getpwall()
        min_uid = common.get_min_uid()
        need_reload = False
        for listuser in users:
            if listuser.pw_uid >= min_uid:
                need_reload = True
                set_user(args, listuser, False)
        if need_reload:
            systemctl_daemon_reload()
    if not args.quiet:
        logging.info("Set successful")
    return 0

def do_pgm(args, users):
    logging.debug("Entering lscgctl, command: %s" % args.command)
    if 'reset' in args.command:
        ret = command_reset(args, users)
    elif 'list' in args.command:
        ret = command_list(users)
    elif 'set' in args.command:
        ret = command_set(args, users)
    else:
        common.fatal_error('Unexpected command: %s' % args.command)
    logging.debug("Exiting lscgctl")
    return ret

def main():
    args, users = init_pgm()
    return do_pgm(args, users)
  
if __name__ == "__main__":
    main()