# Authors: Simo Sorce <ssorce@redhat.com>
#
# Copyright (C) 2007    Red Hat
# see file 'COPYING' for use and warranty information
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; version 2 only
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.    See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#

import logging
import socket
import errno
import getpass
import os
import re
import fileinput
import sys
import struct
import fcntl

from ipapython import ipautil
from ipapython import dnsclient

def get_fqdn():
    fqdn = ""
    try:
        fqdn = socket.getfqdn()
    except:
        try:
            fqdn = socket.gethostname()
        except:
            fqdn = ""
    return fqdn

def verify_fqdn(host_name,no_host_dns=False):

    if len(host_name.split(".")) < 2 or host_name == "localhost.localdomain":
        raise RuntimeError("Invalid hostname: " + host_name)

    try:
        hostaddr = socket.getaddrinfo(host_name, None)
    except:
        raise RuntimeError("Unable to resolve host name, check /etc/hosts or DNS name resolution")

    if len(hostaddr) == 0:
        raise RuntimeError("Unable to resolve host name, check /etc/hosts or DNS name resolution")

    for a in hostaddr:
        if a[4][0] == '127.0.0.1' or a[4][0] == '::1':
            raise RuntimeError("The IPA Server hostname cannot resolve to localhost (%s). A routable IP address must be used. Check /etc/hosts to see if %s is an alias for %s" % (a[4][0], host_name, a[4][0]))
        try:
            revaddr = a[4][0]
            revname = socket.gethostbyaddr(a[4][0])[0]
        except:
            raise RuntimeError("Unable to resolve the reverse ip address, check /etc/hosts or DNS name resolution")
        if revname != host_name:
            raise RuntimeError("The host name %s does not match the reverse lookup %s" % (host_name, revname))

    if no_host_dns:
        print "Warning: skipping DNS resolution of host", host_name
        return

    # Verify this is NOT a CNAME
    rs = dnsclient.query(host_name+".", dnsclient.DNS_C_IN, dnsclient.DNS_T_CNAME)
    if len(rs) != 0:
        for rsn in rs:
            if rsn.dns_type == dnsclient.DNS_T_CNAME:
                raise RuntimeError("The IPA Server Hostname cannot be a CNAME, only A names are allowed.")

    # Verify that it is a DNS A record
    rs = dnsclient.query(host_name+".", dnsclient.DNS_C_IN, dnsclient.DNS_T_A)
    if len(rs) == 0:
        print "Warning: Hostname (%s) not found in DNS" % host_name
        return

    rec = None
    for rsn in rs:
        if rsn.dns_type == dnsclient.DNS_T_A:
            rec = rsn
            break

    if rec == None:
        print "Warning: Hostname (%s) not found in DNS" % host_name
        return

    # Compare the forward and reverse
    forward = rec.dns_name

    addr = socket.inet_ntoa(struct.pack('<L',rec.rdata.address))
    ipaddr = socket.inet_ntoa(struct.pack('!L',rec.rdata.address))
    if revaddr != ipaddr:
        raise RuntimeError("The network address %s does not match the reverse lookup %s. Check /etc/hosts and ensure that %s is the IP address for %s" % (ipaddr, revaddr, ipaddr, host_name))

    addr = addr + ".in-addr.arpa."
    rs = dnsclient.query(addr, dnsclient.DNS_C_IN, dnsclient.DNS_T_PTR)
    if len(rs) == 0:
        raise RuntimeError("Cannot find Reverse Address for %s (%s)" % (host_name, addr))

    rev = None
    for rsn in rs:
        if rsn.dns_type == dnsclient.DNS_T_PTR:
            rev = rsn
            break

    if rev == None:
        raise RuntimeError("Cannot find Reverse Address for %s (%s)" % (host_name, addr))

    reverse = rev.rdata.ptrdname

    if forward != reverse:
        raise RuntimeError("The DNS forward record %s does not match the reverse address %s" % (forward, reverse))

def verify_ip_address(ip):
    is_ok = True
    try:
        socket.inet_pton(socket.AF_INET, ip)
    except:
        try:
            socket.inet_pton(socket.AF_INET6, ip)
        except:
            print "Unable to verify IP address"
            is_ok = False
    return is_ok

def read_ip_address(host_name, fstore):
    while True:
        ip = ipautil.user_input("Please provide the IP address to be used for this host name", allow_empty = False)

        if ip == "127.0.0.1" or ip == "::1":
            print "The IPA Server can't use localhost as a valid IP"
            continue

        if verify_ip_address(ip):
            break

    print "Adding ["+ip+" "+host_name+"] to your /etc/hosts file"
    fstore.backup_file("/etc/hosts")
    hosts_fd = open('/etc/hosts', 'r+')
    hosts_fd.seek(0, 2)
    hosts_fd.write(ip+'\t'+host_name+' '+host_name.split('.')[0]+'\n')
    hosts_fd.close()

    return ip

def read_dns_forwarders():
    addrs = []
    if ipautil.user_input("Do you want to configure DNS forwarders?", True):
        print "Enter the IP address of DNS forwarder to use, or press Enter to finish."

        while True:
            ip = ipautil.user_input("Enter IP address for a DNS forwarder",
                                    allow_empty=True)
            if not ip:
                break
            if ip == "127.0.0.1" or ip == "::1":
                print "You cannot use localhost as a DNS forwarder"
                continue
            if not verify_ip_address(ip):
                print "DNS forwarder %s not added" % ip
                continue

            print "DNS forwarder %s added" % ip
            addrs.append(ip)

    if not addrs:
        print "No DNS forwarders configured"

    return addrs

def port_available(port):
    """Try to bind to a port on the wildcard host
       Return 1 if the port is available
       Return 0 if the port is in use
    """
    rv = 1

    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        fcntl.fcntl(s, fcntl.F_SETFD, fcntl.FD_CLOEXEC)
        s.bind(('', port))
        s.close()
    except socket.error, e:
        if e[0] == errno.EADDRINUSE:
            rv = 0

    if rv:
        try:
            s = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
            s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
            fcntl.fcntl(s, fcntl.F_SETFD, fcntl.FD_CLOEXEC)
            s.bind(('', port))
            s.close()
        except socket.error, e:
            if e[0] == errno.EADDRINUSE:
                rv = 0

    return rv

def standard_logging_setup(log_filename, debug=False, filemode='w'):
    old_umask = os.umask(077)
    # Always log everything (i.e., DEBUG) to the log
    # file.
    logging.basicConfig(level=logging.DEBUG,
                        format='%(asctime)s %(levelname)s %(message)s',
                        filename=log_filename,
                        filemode=filemode)
    os.umask(old_umask)

    console = logging.StreamHandler()
    # If the debug option is set, also log debug messages to the console
    if debug:
        console.setLevel(logging.DEBUG)
    else:
        # Otherwise, log critical and error messages
        console.setLevel(logging.ERROR)
    formatter = logging.Formatter('%(name)-12s: %(levelname)-8s %(message)s')
    console.setFormatter(formatter)
    logging.getLogger('').addHandler(console)

def get_password(prompt):
    if os.isatty(sys.stdin.fileno()):
        return getpass.getpass(prompt)
    else:
        return sys.stdin.readline().rstrip()

def read_password(user, confirm=True, validate=True):
    correct = False
    pwd = ""
    while not correct:
        pwd = get_password(user + " password: ")
        if not pwd:
            continue
        if validate and len(pwd) < 8:
            print "Password must be at least 8 characters long"
            continue
        if not confirm:
            correct = True
            continue
        pwd_confirm = get_password("Password (confirm): ")
        if pwd != pwd_confirm:
            print "Password mismatch!"
            print ""
        else:
            correct = True
    print ""
    return pwd

def update_file(filename, orig, subst):
    if os.path.exists(filename):
        pattern = "%s" % re.escape(orig)
        p = re.compile(pattern)
        for line in fileinput.input(filename, inplace=1):
            if not p.search(line):
                sys.stdout.write(line)
            else:
                sys.stdout.write(p.sub(subst, line))
        fileinput.close()
        return 0
    else:
        print "File %s doesn't exist." % filename
        return 1

def set_directive(filename, directive, value, quotes=True, separator=' '):
    """Set a name/value pair directive in a configuration file.

       This has only been tested with nss.conf
    """
    valueset = False
    fd = open(filename)
    newfile = []
    for line in fd:
        if directive in line:
            valueset = True
            if quotes:
                newfile.append('%s%s"%s"\n' % (directive, separator, value))
            else:
                newfile.append('%s%s%s\n' % (directive, separator, value))
        else:
            newfile.append(line)
    fd.close()
    if not valueset:
        if quotes:
            newfile.append('%s%s"%s"\n' % (directive, separator, value))
        else:
            newfile.append('%s%s%s\n' % (directive, separator, value))

    fd = open(filename, "w")
    fd.write("".join(newfile))
    fd.close()

def get_directive(filename, directive, separator=' '):
    """
    A rather inefficient way to get a configuration directive.
    """
    fd = open(filename, "r")
    for line in fd:
        if directive in line:
            line = line.strip()
            result = line.split(separator, 1)[1]
            result = result.strip('"')
            result = result.strip(' ')
            fd.close()
            return result
    fd.close()
    return None

def kadmin(command):
    ipautil.run(["kadmin.local", "-q", command])

def kadmin_addprinc(principal):
    kadmin("addprinc -randkey " + principal)

def kadmin_modprinc(principal, options):
    kadmin("modprinc " + options + " " + principal)

def create_keytab(path, principal):
    try:
        if ipautil.file_exists(path):
            os.remove(path)
    except os.error:
        logging.critical("Failed to remove %s." % path)

    kadmin("ktadd -k " + path + " " + principal)