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Current Directory: /opt/custom-ns
Viewing File: /opt/custom-ns/named.py
"""functions for configuring named for custom-ns"""

import fileinput
import shlex
import shutil
import string
import random
import re
import os
from subprocess import run, CalledProcessError
import netaddr
from blessings import Terminal
from cpapis import whmapi1, CpAPIError

TERM = Terminal()


def disable_recursion():
    """Disable DNS recursion in named.conf"""
    new_conf = []
    new_options = '    allow-recursion {"none";};\n    recursion no;'
    try:
        with open('/etc/named.conf', encoding='utf-8') as named_file:
            named_conf = named_file.read().splitlines()
    except OSError:
        print(
            TERM.bold_red(
                'Unable to disable recursion in named.conf '
                '(named.conf is not readable)'
            )
        )
        return
    parsing_options = False
    options_re = re.compile(r'options\s*\{')
    # for each line in the original conf
    for line in named_conf:
        # if 'options {' is encountered, we are within the options section
        if options_re.search(line) is not None:
            parsing_options = True
        # if in the options section and there is a recursion setting, remove it
        if 'recursion' in line and parsing_options:
            continue
        # once the end of options section is hit, insert new_options
        if parsing_options and line.strip() == '};':
            new_conf.append(new_options)
            parsing_options = False
        new_conf.append(line)
    temp_path = f'/tmp/.{_randstr(20)}'
    with open(temp_path, 'w', encoding='utf-8') as temp_file:
        temp_file.write('%s\n' % '\n'.join(new_conf))
    try:
        run(['named_checkconf', temp_path], check=True)
    except (CalledProcessError, FileNotFoundError):
        print(
            TERM.bold_red(
                'Unable to disable recursion in named.conf '
                'due to syntax error. Reverting named.conf'
            )
        )
        os.remove(temp_path)
        return
    try:
        shutil.move(temp_path, '/etc/named.conf')
    except OSError:
        print(
            TERM.bold_red(
                f'could not rename {temp_path} to /etc/named.conf. '
                'Do this manually.'
            )
        )


def _randstr(num: int) -> str:
    chars = string.ascii_lowercase + string.digits
    return ''.join(random.choice(chars) for _ in range(num))


def set_soa_record(domain, full_ns1):
    """Edit SOA records for a domain"""
    try:
        zone = whmapi1('dumpzone', {'domain': domain}, check=True)
        zone = zone['data']['zone'][0]['record']
    except (TypeError, KeyError, IndexError, CpAPIError):
        print(
            TERM.bold_red(
                f'Could not read existing zone for {domain} to edit SOA '
                'records'
            )
        )
        return
    for zrecord in zone:
        if zrecord['type'] == 'SOA':
            zrecord['mname'] = full_ns1.strip('.')
            zrecord['domain'] = domain

            try:
                whmapi1('editzonerecord', zrecord, check=True)
            except CpAPIError as err:
                print(err)


def set_ns_records(domain, ns1_name, ns1_addr, ns2_name, ns2_addr):
    """Add A or AAAA records to appropriate zone files"""
    full_ns1 = f'{ns1_name}.{domain}.'
    full_ns2 = f'{ns2_name}.{domain}.'
    # delete any existing records
    try:
        zone = whmapi1('dumpzone', {'domain': domain}, check=True)
        zone = zone['data']['zone'][0]['record']
    except (TypeError, KeyError, IndexError):
        print(
            TERM.bold_red(
                f'Could not read existing zone for {domain} to delete '
                'any existing ns records'
            )
        )
        zone = []
    except CpAPIError as err:
        print(err)
    zdel = []

    for zrecord in zone:
        if zrecord['type'] not in ('A', 'AAAA'):
            continue
        if zrecord['name'] in (full_ns1, full_ns2):
            zdel.append(zrecord['Line'])
    all_removed = True
    while len(zdel) > 0:
        try:
            whmapi1(
                'removezonerecord',
                {'domain': domain, 'line': zdel.pop(-1)},
                check=True,
            )
        except CpAPIError as err:
            print(err)
            all_removed = False
    if not all_removed:
        print(
            TERM.bold_red(
                'failed to remove at least one old A record from '
                f'{domain} for ns1 or ns2 - check the zone manually'
            )
        )
    # add the new 'A' or 'AAAA" records for ns1/ns2
    for name, addr in ((ns1_name, ns1_addr), (ns2_name, ns2_addr)):
        if netaddr.valid_ipv4(addr):
            addr_type = 'A'
        else:
            addr_type = 'AAAA'
        try:
            whmapi1(
                'addzonerecord',
                {
                    'name': name,
                    'domain': domain,
                    'type': addr_type,
                    'address': addr,
                },
                check=True,
            )
        except CpAPIError as err:
            print(
                TERM.bold_red(
                    f'Could not set {addr_type} record for {name}.{domain}'
                )
            )
            print(err)
    # go through all other zones and edit their 'IN NS' records
    mass_fix_ns_records(full_ns1, full_ns2)


def mass_fix_ns_records(full_ns1, full_ns2):
    """Go through every zone on the server and adjust their 'IN NS' records"""
    print(
        "Adjusting all existing zones' NS and SOA records",
        "(this may take a while)",
    )
    try:
        all_zones = [
            x['domain']
            for x in whmapi1('listzones', check=True)['data']['zone']
        ]
    except (TypeError, KeyError):
        all_zones = []
        print(
            TERM.bold_red(
                'could not retrieve a list of all zones on the server - '
                'they will all need their NS and SOA records adjusted manually.'
            )
        )
    except CpAPIError as err:
        all_zones = []
        print(err)

    for domain in all_zones:
        set_soa_record(domain, full_ns1)
        try:
            zone = whmapi1('dumpzone', {'domain': domain}, check=True)
            zone = zone['data']['zone'][0]['record']
        except (TypeError, IndexError, KeyError):
            zone = []
            print(
                TERM.bold_red(
                    f'Could not list contents of zone {domain} to adjust '
                    'its NS records - do this manually'
                )
            )
        except CpAPIError as err:
            zone = []
            print(err)
        zdel = []
        for zrecord in zone:
            if zrecord['type'] == 'NS':
                zdel.append(zrecord['Line'])
        all_removed = True
        while len(zdel) > 0:
            try:
                whmapi1(
                    'removezonerecord',
                    {'domain': domain, 'line': zdel.pop(-1)},
                    check=True,
                )
            except CpAPIError as err:
                print(err)
                all_removed = False
        if not all_removed:
            print(
                TERM.bold_red(
                    'failed to remove old NS record from '
                    f'{domain} - check the zone manually'
                )
            )
        for new_record in (full_ns1, full_ns2):
            try:
                whmapi1(
                    'addzonerecord',
                    {
                        'nsdname': new_record.strip('.'),
                        'domain': domain,
                        'name': f'{domain}.',
                        'type': 'NS',
                    },
                    check=True,
                )
            except CpAPIError as err:
                print(
                    TERM.bold_red(
                        f'Failed to add NS record of {new_record} '
                        f'to {domain}.db'
                    )
                )
                print(err)


def enable_in_chkservd():
    """Enable BIND in chkservd"""
    if not os.path.isfile('/etc/chkserv.d/chkservd.conf'):
        print(TERM.bold_red('Cannot enable named in chkservd'))
        return
    with open('/etc/chkserv.d/chkservd.conf', encoding='utf-8') as chkserv:
        data = chkserv.read().splitlines()
    found = False
    for index, line in enumerate(data):
        if line.startswith('named:'):
            found = True
            data[index] = 'named:1'
    if not found:
        data.append('named:1')
    with open('/etc/chkserv.d/chkservd.conf', 'w', encoding='utf-8') as chkserv:
        chkserv.write('%s\n' % '\n'.join(data))
    with open('/etc/chkserv.d/named', 'w', encoding='utf-8') as named_chk:
        named_chk.write(
            'service[named]=x,x,x,'
            '/usr/local/cpanel/scripts/restartsrv_named,'
            'named|bind|nsd|mydns,named|bind|nsd|mydns\n'
        )


def enable_bind():
    """Run /scripts/setupnameserver"""
    cmd = ['/usr/local/cpanel/scripts/setupnameserver', 'bind']
    try:
        run(cmd, check=True)
    except (FileNotFoundError, CalledProcessError):
        print(TERM.bold_red(f'Unable to run {shlex.join(cmd)}'))


def rndc_reload():
    """Try to run rndc reload and print a red error if it fails"""
    try:
        run(['rndc', 'reload'], check=True)
    except (FileNotFoundError, CalledProcessError):
        print(TERM.bold_red('Error running rndc reload'))


def allow_query_all():
    """Remove line from /etc/named.conf that restricts
    hosts allowed to query nameservers"""
    for line in fileinput.input(files='/etc/named.conf', inplace=True):
        if "allow-query" not in line:
            print(line, end=' ')
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