path: root/src/lib/Bcfg2/Client/Tools/POSIX.py

"""All POSIX Type client support for Bcfg2."""

import binascii
from datetime import datetime
import difflib
import errno
import grp
import logging
import os
import pwd
import shutil
import stat
import sys
import time
# py3k compatibility
if sys.hexversion >= 0x03000000:
    unicode = str

import Bcfg2.Client.Tools
import Bcfg2.Options
from Bcfg2.Client import XML

log = logging.getLogger('POSIX')

# map between dev_type attribute and stat constants
device_map = {'block': stat.S_IFBLK,
              'char': stat.S_IFCHR,
              'fifo': stat.S_IFIFO}


def calcPerms(initial, perms):
    """This compares ondisk permissions with specified ones."""
    pdisp = [{1:stat.S_ISVTX, 2:stat.S_ISGID, 4:stat.S_ISUID},
             {1:stat.S_IXUSR, 2:stat.S_IWUSR, 4:stat.S_IRUSR},
             {1:stat.S_IXGRP, 2:stat.S_IWGRP, 4:stat.S_IRGRP},
             {1:stat.S_IXOTH, 2:stat.S_IWOTH, 4:stat.S_IROTH}]
    tempperms = initial
    if len(perms) == 3:
        perms = '0%s' % (perms)
    pdigits = [int(perms[digit]) for digit in range(4)]
    for index in range(4):
        for (num, perm) in list(pdisp[index].items()):
            if pdigits[index] & num:
                tempperms |= perm
    return tempperms


def normGid(entry, logger=None):
    """
       This takes a group name or gid and
       returns the corresponding gid or False.
    """
    if logger is None:
        logger = log
    try:
        try:
            return int(entry.get('group'))
        except:
            return int(grp.getgrnam(entry.get('group'))[2])
    except (OSError, KeyError):
        logger.error('GID normalization failed for %s. Does group %s exist?' %
                     (entry.get('name'), entry.get('group')))
        return False


def normUid(entry, logger=None):
    """
       This takes a user name or uid and
       returns the corresponding uid or False.
    """
    if logger is None:
        logger = log
    try:
        try:
            return int(entry.get('owner'))
        except:
            return int(pwd.getpwnam(entry.get('owner'))[2])
    except (OSError, KeyError):
        logger.error('UID normalization failed for %s. Does owner %s exist?' %
                     (entry.get('name'), entry.get('owner')))
        return False


def isString(strng, encoding):
    """
       Returns true if the string contains no ASCII control characters
       and can be decoded from the specified encoding.
    """
    for char in strng:
        if ord(char) < 9 or ord(char) > 13 and ord(char) < 32:
            return False
    try:
        strng.decode(encoding)
        return True
    except:
        return False


class POSIX(Bcfg2.Client.Tools.Tool):
    """POSIX File support code."""
    name = 'POSIX'
    __handles__ = [('Path', 'device'),
                   ('Path', 'directory'),
                   ('Path', 'file'),
                   ('Path', 'hardlink'),
                   ('Path', 'nonexistent'),
                   ('Path', 'permissions'),
                   ('Path', 'symlink')]
    __req__ = {'Path': ['name', 'type']}

    # grab paranoid options from /etc/bcfg2.conf
    opts = {'ppath': Bcfg2.Options.PARANOID_PATH,
            'max_copies': Bcfg2.Options.PARANOID_MAX_COPIES}
    setup = Bcfg2.Options.OptionParser(opts)
    setup.parse([])
    ppath = setup['ppath']
    max_copies = setup['max_copies']

    def canInstall(self, entry):
        """Check if entry is complete for installation."""
        if Bcfg2.Client.Tools.Tool.canInstall(self, entry):
            if (entry.tag,
                entry.get('type'),
                entry.text,
                entry.get('empty', 'false')) == ('Path',
                                                 'file',
                                                 None,
                                                 'false'):
                return False
            return True
        else:
            return False

    def gatherCurrentData(self, entry):
        if entry.tag == 'Path' and entry.get('type') == 'file':
            try:
                ondisk = os.stat(entry.get('name'))
            except OSError:
                entry.set('current_exists', 'false')
                self.logger.debug("%s %s does not exist" %
                                  (entry.tag, entry.get('name')))
                return False
            try:
                entry.set('current_owner', str(ondisk[stat.ST_UID]))
                entry.set('current_group', str(ondisk[stat.ST_GID]))
            except (OSError, KeyError):
                pass
            entry.set('perms', str(oct(ondisk[stat.ST_MODE])[-4:]))

    def Verifydevice(self, entry, _):
        """Verify device entry."""
        if entry.get('dev_type') == None or \
           entry.get('owner') == None or \
           entry.get('group') == None:
            self.logger.error('Entry %s not completely specified. '
                              'Try running bcfg2-lint.' % (entry.get('name')))
            return False
        if entry.get('dev_type') in ['block', 'char']:
            # check if major/minor are properly specified
            if entry.get('major') == None or \
               entry.get('minor') == None:
                self.logger.error('Entry %s not completely specified. '
                                  'Try running bcfg2-lint.' % (entry.get('name')))
                return False
        try:
            # check for file existence
            filestat = os.stat(entry.get('name'))
        except OSError:
            entry.set('current_exists', 'false')
            self.logger.debug("%s %s does not exist" %
                              (entry.tag, entry.get('name')))
            return False

        try:
            # attempt to verify device properties as specified in config
            dev_type = entry.get('dev_type')
            mode = calcPerms(device_map[dev_type],
                             entry.get('mode', '0600'))
            owner = normUid(entry, logger=self.logger)
            group = normGid(entry, logger=self.logger)
            if dev_type in ['block', 'char']:
                # check for incompletely specified entries
                if entry.get('major') == None or \
                   entry.get('minor') == None:
                    self.logger.error('Entry %s not completely specified. '
                                      'Try running bcfg2-lint.' % (entry.get('name')))
                    return False
                major = int(entry.get('major'))
                minor = int(entry.get('minor'))
                if major == os.major(filestat.st_rdev) and \
                   minor == os.minor(filestat.st_rdev) and \
                   mode == filestat.st_mode and \
                   owner == filestat.st_uid and \
                   group == filestat.st_gid:
                    return True
                else:
                    return False
            elif dev_type == 'fifo' and \
                 mode == filestat.st_mode and \
                 owner == filestat.st_uid and \
                 group == filestat.st_gid:
                return True
            else:
                self.logger.info('Device properties for %s incorrect' % \
                                 entry.get('name'))
                return False
        except OSError:
            self.logger.debug("%s %s failed to verify" %
                              (entry.tag, entry.get('name')))
            return False

    def Installdevice(self, entry):
        """Install device entries."""
        try:
            # check for existing paths and remove them
            os.lstat(entry.get('name'))
            try:
                os.unlink(entry.get('name'))
                exists = False
            except OSError:
                self.logger.info('Failed to unlink %s' % \
                                 entry.get('name'))
                return False
        except OSError:
            exists = False

        if not exists:
            try:
                dev_type = entry.get('dev_type')
                mode = calcPerms(device_map[dev_type],
                                 entry.get('mode', '0600'))
                if dev_type in ['block', 'char']:
                    # check if major/minor are properly specified
                    if entry.get('major') == None or \
                       entry.get('minor') == None:
                        self.logger.error('Entry %s not completely specified. '
                                          'Try running bcfg2-lint.' % (entry.get('name')))
                        return False
                    major = int(entry.get('major'))
                    minor = int(entry.get('minor'))
                    device = os.makedev(major, minor)
                    os.mknod(entry.get('name'), mode, device)
                else:
                    os.mknod(entry.get('name'), mode)
                """
                Python uses the OS mknod(2) implementation which modifies the
                mode based on the umask of the running process.  Therefore, the
                following chmod(2) call is needed to make sure the permissions
                are set as specified by the user.
                """
                os.chmod(entry.get('name'), mode)
                os.chown(entry.get('name'),
                         normUid(entry, logger=self.logger),
                         normGid(entry, logger=self.logger))
                return True
            except KeyError:
                self.logger.error('Failed to install %s' % entry.get('name'))
            except OSError:
                self.logger.error('Failed to install %s' % entry.get('name'))
                return False

    def Verifydirectory(self, entry, modlist):
        """Verify Path type='directory' entry."""
        if entry.get('perms') == None or \
           entry.get('owner') == None or \
           entry.get('group') == None:
            self.logger.error("POSIX: Entry %s not completely specified. "
                              "Try running bcfg2-lint." % (entry.get('name')))
            return False
        while len(entry.get('perms', '')) < 4:
            entry.set('perms', '0' + entry.get('perms', ''))
        try:
            ondisk = os.stat(entry.get('name'))
        except OSError:
            entry.set('current_exists', 'false')
            self.logger.info("POSIX: %s %s does not exist" %
                              (entry.tag, entry.get('name')))
            return False
        try:
            owner = str(ondisk[stat.ST_UID])
            group = str(ondisk[stat.ST_GID])
        except (OSError, KeyError):
            self.logger.info("POSIX: User/Group resolution failed "
                             "for path %s" % entry.get('name'))
            owner = 'root'
            group = '0'
        finfo = os.stat(entry.get('name'))
        perms = oct(finfo[stat.ST_MODE])[-4:]
        if entry.get('mtime', '-1') != '-1':
            mtime = str(finfo[stat.ST_MTIME])
        else:
            mtime = '-1'
        pTrue = ((owner == str(normUid(entry, logger=self.logger))) and
                 (group == str(normGid(entry, logger=self.logger))) and
                 (perms == entry.get('perms')) and
                 (mtime == entry.get('mtime', '-1')))

        pruneTrue = True
        ex_ents = []
        if entry.get('prune', 'false') == 'true' \
           and (entry.tag == 'Path' and entry.get('type') == 'directory'):
            # check for any extra entries when prune='true' attribute is set
            try:
                entries = ['/'.join([entry.get('name'), ent]) \
                           for ent in os.listdir(entry.get('name'))]
                ex_ents = [e for e in entries if e not in modlist]
                if ex_ents:
                    pruneTrue = False
                    self.logger.info("POSIX: Directory %s contains "
                                     "extra entries:" % entry.get('name'))
                    self.logger.info(ex_ents)
                    nqtext = entry.get('qtext', '') + '\n'
                    nqtext += "Directory %s contains extra entries: " % \
                              entry.get('name')
                    nqtext += ":".join(ex_ents)
                    entry.set('qtest', nqtext)
                    [entry.append(XML.Element('Prune', path=x)) \
                     for x in ex_ents]
            except OSError:
                ex_ents = []
                pruneTrue = True

        if not pTrue:
            if owner != str(normUid(entry, logger=self.logger)):
                entry.set('current_owner', owner)
                self.logger.debug("%s %s ownership wrong" % \
                                  (entry.tag, entry.get('name')))
                nqtext = entry.get('qtext', '') + '\n'
                nqtext += "%s owner wrong. is %s should be %s" % \
                          (entry.get('name'), owner, entry.get('owner'))
                entry.set('qtext', nqtext)
            if group != str(normGid(entry, logger=self.logger)):
                entry.set('current_group', group)
                self.logger.debug("%s %s group wrong" % \
                                  (entry.tag, entry.get('name')))
                nqtext = entry.get('qtext', '') + '\n'
                nqtext += "%s group is %s should be %s" % \
                          (entry.get('name'), group, entry.get('group'))
                entry.set('qtext', nqtext)
            if perms != entry.get('perms'):
                entry.set('current_perms', perms)
                self.logger.debug("%s %s permissions are %s should be %s" %
                                  (entry.tag,
                                   entry.get('name'),
                                   perms,
                                   entry.get('perms')))
                nqtext = entry.get('qtext', '') + '\n'
                nqtext += "%s %s perms are %s should be %s" % \
                          (entry.tag,
                           entry.get('name'),
                           perms,
                           entry.get('perms'))
                entry.set('qtext', nqtext)
            if mtime != entry.get('mtime', '-1'):
                entry.set('current_mtime', mtime)
                self.logger.debug("%s %s mtime is %s should be %s" \
                                  % (entry.tag, entry.get('name'), mtime,
                                     entry.get('mtime')))
                nqtext = entry.get('qtext', '') + '\n'
                nqtext += "%s mtime is %s should be %s" % \
                          (entry.get('name'), mtime, entry.get('mtime'))
                entry.set('qtext', nqtext)
            if entry.get('type') != 'file':
                nnqtext = entry.get('qtext')
                nnqtext += '\nInstall %s %s: (y/N) ' % (entry.get('type'),
                                                        entry.get('name'))
                entry.set('qtext', nnqtext)
        return pTrue and pruneTrue

    def Installdirectory(self, entry):
        """Install Path type='directory' entry."""
        if entry.get('perms') == None or \
           entry.get('owner') == None or \
           entry.get('group') == None:
            self.logger.error('Entry %s not completely specified. '
                              'Try running bcfg2-lint.' % \
                              (entry.get('name')))
            return False
        self.logger.info("Installing directory %s" % (entry.get('name')))
        try:
            fmode = os.lstat(entry.get('name'))
            if not stat.S_ISDIR(fmode[stat.ST_MODE]):
                self.logger.debug("Found a non-directory entry at %s" % \
                                  (entry.get('name')))
                try:
                    os.unlink(entry.get('name'))
                    exists = False
                except OSError:
                    self.logger.info("Failed to unlink %s" % \
                                     (entry.get('name')))
                    return False
            else:
                self.logger.debug("Found a pre-existing directory at %s" % \
                                  (entry.get('name')))
                exists = True
        except OSError:
            # stat failed
            exists = False

        if not exists:
            parent = "/".join(entry.get('name').split('/')[:-1])
            if parent:
                try:
                    os.stat(parent)
                except:
                    self.logger.debug('Creating parent path for directory %s' % (entry.get('name')))
                    for idx in range(len(parent.split('/')[:-1])):
                        current = '/'+'/'.join(parent.split('/')[1:2+idx])
                        try:
                            sloc = os.stat(current)
                        except OSError:
                            try:
                                os.mkdir(current)
                                continue
                            except OSError:
                                return False
                        if not stat.S_ISDIR(sloc[stat.ST_MODE]):
                            try:
                                os.unlink(current)
                                os.mkdir(current)
                            except OSError:
                                return False

            try:
                os.mkdir(entry.get('name'))
            except OSError:
                self.logger.error('Failed to create directory %s' % \
                                  (entry.get('name')))
                return False
        if entry.get('prune', 'false') == 'true' and entry.get("qtest"):
            for pent in entry.findall('Prune'):
                pname = pent.get('path')
                ulfailed = False
                if os.path.isdir(pname):
                    self.logger.info("Not removing extra directory %s, "
                                     "please check and remove manually" % pname)
                    continue
                try:
                    self.logger.debug("Unlinking file %s" % pname)
                    os.unlink(pname)
                except OSError:
                    self.logger.error("Failed to unlink path %s" % pname)
                    ulfailed = True
            if ulfailed:
                return False
        return self.Installpermissions(entry)

    def Verifyfile(self, entry, _):
        """Verify Path type='file' entry."""
        # permissions check + content check
        permissionStatus = self.Verifydirectory(entry, _)
        tbin = False
        if entry.text == None and entry.get('empty', 'false') == 'false':
            self.logger.error("Cannot verify incomplete Path type='%s' %s" %
                              (entry.get('type'), entry.get('name')))
            return False
        if entry.get('encoding', 'ascii') == 'base64':
            tempdata = binascii.a2b_base64(entry.text)
            tbin = True
        elif entry.get('empty', 'false') == 'true':
            tempdata = ''
        else:
            tempdata = entry.text
            if type(tempdata) == unicode:
                try:
                    tempdata = tempdata.encode(self.setup['encoding'])
                except UnicodeEncodeError:
                    e = sys.exc_info()[1]
                    self.logger.error("Error encoding file %s:\n %s" % \
                                      (entry.get('name'), e))

        different = False
        content = None
        if not os.path.exists(entry.get("name")):
            # first, see if the target file exists at all; if not,
            # they're clearly different
            different = True
            content = ""
        else:
            # next, see if the size of the target file is different
            # from the size of the desired content
            try:
                estat = os.stat(entry.get('name'))
            except OSError:
                err = sys.exc_info()[1]
                self.logger.error("Failed to stat %s: %s" %
                                  (err.filename, err))
                return False
            if len(tempdata) != estat[stat.ST_SIZE]:
                different = True
            else:
                # finally, read in the target file and compare them
                # directly. comparison could be done with a checksum,
                # which might be faster for big binary files, but
                # slower for everything else
                try:
                    content = open(entry.get('name')).read()
                except IOError:
                    err = sys.exc_info()[1]
                    self.logger.error("Failed to read %s: %s" %
                                      (err.filename, err))
                    return False
                different = content != tempdata

        if different:
            if self.setup['interactive']:
                prompt = [entry.get('qtext', '')]
                if not tbin and content is None:
                    # it's possible that we figured out the files are
                    # different without reading in the local file.  if
                    # the supplied version of the file is not binary,
                    # we now have to read in the local file to figure
                    # out if _it_ is binary, and either include that
                    # fact or the diff in our prompts for -I
                    try:
                        content = open(entry.get('name')).read()
                    except IOError:
                        err = sys.exc_info()[1]
                        self.logger.error("Failed to read %s: %s" %
                                          (err.filename, err))
                        return False
                if tbin or not isString(content, self.setup['encoding']):
                    # don't compute diffs if the file is binary
                    prompt.append('Binary file, no printable diff')
                else:
                    diff = self._diff(content, tempdata,
                                      difflib.unified_diff,
                                      filename=entry.get("name"))
                    if diff:
                        udiff = '\n'.join(diff)
                        try:
                            prompt.append(udiff.decode(self.setup['encoding']))
                        except UnicodeDecodeError:
                            prompt.append("Binary file, no printable diff")
                    else:
                        prompt.append("Diff took too long to compute, no "
                                      "printable diff")
                prompt.append("Install %s %s: (y/N): " % (entry.tag,
                                                          entry.get('name')))
                entry.set("qtext", "\n".join(prompt))

            if entry.get('sensitive', 'false').lower() != 'true':
                if content is None:
                    # it's possible that we figured out the files are
                    # different without reading in the local file.  we
                    # now have to read in the local file to figure out
                    # if _it_ is binary, and either include the whole
                    # file or the diff for reports
                    try:
                        content = open(entry.get('name')).read()
                    except IOError:
                        err = sys.exc_info()[1]
                        self.logger.error("Failed to read %s: %s" %
                                          (err.filename, err))
                        return False

                if tbin or not isString(content, self.setup['encoding']):
                    # don't compute diffs if the file is binary
                    entry.set('current_bfile', binascii.b2a_base64(content))
                else:
                    diff = self._diff(content, tempdata, difflib.ndiff,
                                      filename=entry.get("name"))
                    if diff:
                        entry.set("current_bdiff",
                                  binascii.b2a_base64("\n".join(diff)))
                    elif not tbin and isString(content, self.setup['encoding']):
                        entry.set('current_bfile', binascii.b2a_base64(content))
        elif permissionStatus == False and self.setup['interactive']:
            prompt = [entry.get('qtext', '')]
            prompt.append("Install %s %s: (y/N): " % (entry.tag,
                                                      entry.get('name')))
            entry.set("qtext", "\n".join(prompt))


        return permissionStatus and not different

    def Installfile(self, entry):
        """Install Path type='file' entry."""
        self.logger.info("Installing file %s" % (entry.get('name')))

        parent = "/".join(entry.get('name').split('/')[:-1])
        if parent:
            try:
                os.stat(parent)
            except:
                self.logger.debug('Creating parent path for config file %s' % \
                                  (entry.get('name')))
                current = '/'
                for next in parent.split('/')[1:]:
                    current += next + '/'
                    try:
                        sloc = os.stat(current)
                        try:
                            if not stat.S_ISDIR(sloc[stat.ST_MODE]):
                                self.logger.debug('%s is not a directory; recreating' \
                                                  % (current))
                                os.unlink(current)
                                os.mkdir(current)
                        except OSError:
                            return False
                    except OSError:
                        try:
                            self.logger.debug("Creating non-existent path %s" % current)
                            os.mkdir(current)
                        except OSError:
                            return False

        # If we get here, then the parent directory should exist
        if (entry.get("paranoid", False) in ['true', 'True']) and \
           self.setup.get("paranoid", False) and not \
           (entry.get('current_exists', 'true') == 'false'):
            bkupnam = entry.get('name').replace('/', '_')
            # current list of backups for this file
            try:
                bkuplist = [f for f in os.listdir(self.ppath) if
                            f.startswith(bkupnam)]
            except OSError:
                e = sys.exc_info()[1]
                self.logger.error("Failed to create backup list in %s: %s" %
                                  (self.ppath, e.strerror))
                return False
            bkuplist.sort()
            while len(bkuplist) >= int(self.max_copies):
                # remove the oldest backup available
                oldest = bkuplist.pop(0)
                self.logger.info("Removing %s" % oldest)
                try:
                    os.remove("%s/%s" % (self.ppath, oldest))
                except:
                    self.logger.error("Failed to remove %s/%s" % \
                                      (self.ppath, oldest))
                    return False
            try:
                # backup existing file
                shutil.copy(entry.get('name'),
                            "%s/%s_%s" % (self.ppath, bkupnam,
                                          datetime.isoformat(datetime.now())))
                self.logger.info("Backup of %s saved to %s" %
                                 (entry.get('name'), self.ppath))
            except IOError:
                e = sys.exc_info()[1]
                self.logger.error("Failed to create backup file for %s" % \
                                  (entry.get('name')))
                self.logger.error(e)
                return False
        try:
            newfile = open("%s.new"%(entry.get('name')), 'w')
            if entry.get('encoding', 'ascii') == 'base64':
                filedata = binascii.a2b_base64(entry.text)
            elif entry.get('empty', 'false') == 'true':
                filedata = ''
            else:
                if type(entry.text) == unicode:
                    filedata = entry.text.encode(self.setup['encoding'])
                else:
                    filedata = entry.text
            newfile.write(filedata)
            newfile.close()
            try:
                os.chown(newfile.name,
                         normUid(entry, logger=self.logger),
                         normGid(entry, logger=self.logger))
            except KeyError:
                self.logger.error("Failed to chown %s to %s:%s" %
                                  (newfile.name, entry.get('owner'),
                                   entry.get('group')))
                os.chown(newfile.name, 0, 0)
            except OSError:
                err = sys.exc_info()[1]
                self.logger.error("Could not chown %s: %s" % (newfile.name,
                                                              err))
            os.chmod(newfile.name, calcPerms(stat.S_IFREG, entry.get('perms')))
            os.rename(newfile.name, entry.get('name'))
            if entry.get('mtime', '-1') != '-1':
                try:
                    os.utime(entry.get('name'), (int(entry.get('mtime')),
                                                 int(entry.get('mtime'))))
                except:
                    self.logger.error("File %s mtime fix failed" \
                                      % (entry.get('name')))
                    return False
            return True
        except (OSError, IOError):
            err = sys.exc_info()[1]
            if err.errno == errno.EACCES:
                self.logger.info("Failed to open %s for writing" % (entry.get('name')))
            else:
                print(err)
            return False

    def Verifyhardlink(self, entry, _):
        """Verify HardLink entry."""
        if entry.get('to') == None:
            self.logger.error('Entry %s not completely specified. '
                              'Try running bcfg2-lint.' % \
                              (entry.get('name')))
            return False
        try:
            if os.path.samefile(entry.get('name'), entry.get('to')):
                return True
            self.logger.debug("Hardlink %s is incorrect" % \
                              entry.get('name'))
            entry.set('qtext', "Link %s to %s? [y/N] " % \
                      (entry.get('name'),
                       entry.get('to')))
            return False
        except OSError:
            entry.set('current_exists', 'false')
            entry.set('qtext', "Link %s to %s? [y/N] " % \
                      (entry.get('name'),
                       entry.get('to')))
            return False

    def Installhardlink(self, entry):
        """Install HardLink entry."""
        if entry.get('to') == None:
            self.logger.error('Entry %s not completely specified. '
                              'Try running bcfg2-lint.' % \
                              (entry.get('name')))
            return False
        self.logger.info("Installing Hardlink %s" % (entry.get('name')))
        if os.path.lexists(entry.get('name')):
            try:
                fmode = os.lstat(entry.get('name'))[stat.ST_MODE]
                if stat.S_ISREG(fmode) or stat.S_ISLNK(fmode):
                    self.logger.debug("Non-directory entry already exists at "
                                      "%s. Unlinking entry." % (entry.get('name')))
                    os.unlink(entry.get('name'))
                elif stat.S_ISDIR(fmode):
                    self.logger.debug("Directory already exists at %s" % \
                                      (entry.get('name')))
                    self.cmd.run("mv %s/ %s.bak" % \
                                 (entry.get('name'),
                                  entry.get('name')))
                else:
                    os.unlink(entry.get('name'))
            except OSError:
                self.logger.info("Hardlink %s cleanup failed" % \
                                 (entry.get('name')))
        try:
            os.link(entry.get('to'), entry.get('name'))
            return True
        except OSError:
            return False

    def Verifynonexistent(self, entry, _):
        """Verify nonexistent entry."""
        # return true if path does _not_ exist
        return not os.path.lexists(entry.get('name'))

    def Installnonexistent(self, entry):
        '''Remove nonexistent entries'''
        ename = entry.get('name')
        if entry.get('recursive') in ['True', 'true']:
            # ensure that configuration spec is consistent first
            if [e for e in self.buildModlist() \
                if e.startswith(ename) and e != ename]:
                self.logger.error('Not installing %s. One or more files '
                                  'in this directory are specified in '
                                  'your configuration.' % ename)
                return False
            try:
                shutil.rmtree(ename)
            except OSError:
                e = sys.exc_info()[1]
                self.logger.error('Failed to remove %s: %s' % (ename,
                                                               e.strerror))
        else:
            if os.path.islink(ename):
                os.remove(ename)
                return True
            elif os.path.isdir(ename):
                try:
                    os.rmdir(ename)
                    return True
                except OSError:
                    e = sys.exc_info()[1]
                    self.logger.error('Failed to remove %s: %s' % (ename,
                                                                   e.strerror))
                    return False
            try:
                os.remove(ename)
                return True
            except OSError:
                e = sys.exc_info()[1]
                self.logger.error('Failed to remove %s: %s' % (ename,
                                                               e.strerror))
                return False

    def Verifypermissions(self, entry, _):
        """Verify Path type='permissions' entry"""
        if entry.get('perms') == None or \
           entry.get('owner') == None or \
           entry.get('group') == None:
            self.logger.error('Entry %s not completely specified. '
                              'Try running bcfg2-lint.' % (entry.get('name')))
            return False
        if entry.get('recursive') in ['True', 'true']:
            # verify ownership information recursively
            owner = normUid(entry, logger=self.logger)
            group = normGid(entry, logger=self.logger)

            for root, dirs, files in os.walk(entry.get('name')):
                for p in dirs + files:
                    path = os.path.join(root, p)
                    pstat = os.stat(path)
                    if owner != pstat.st_uid:
                        # owner mismatch for path
                        entry.set('current_owner', str(pstat.st_uid))
                        self.logger.debug("%s %s ownership wrong" % \
                                          (entry.tag, path))
                        nqtext = entry.get('qtext', '') + '\n'
                        nqtext += ("Owner for path %s is incorrect. "
                                   "Current owner is %s but should be %s\n" % \
                                   (path, pstat.st_uid, entry.get('owner')))
                        nqtext += ("\nInstall %s %s: (y/N): " %
                                   (entry.tag, entry.get('name')))
                        entry.set('qtext', nqtext)
                        return False
                    if group != pstat.st_gid:
                        # group mismatch for path
                        entry.set('current_group', str(pstat.st_gid))
                        self.logger.debug("%s %s group wrong" % \
                                          (entry.tag, path))
                        nqtext = entry.get('qtext', '') + '\n'
                        nqtext += ("Group for path %s is incorrect. "
                                   "Current group is %s but should be %s\n" % \
                                   (path, pstat.st_gid, entry.get('group')))
                        nqtext += ("\nInstall %s %s: (y/N): " %
                                   (entry.tag, entry.get('name')))
                        entry.set('qtext', nqtext)
                        return False
        return self.Verifydirectory(entry, _)

    def _diff(self, content1, content2, difffunc, filename=None):
        rv = []
        start = time.time()
        longtime = False
        for diffline in difffunc(content1.split('\n'),
                                 content2.split('\n')):
            now = time.time()
            rv.append(diffline)
            if now - start > 5 and not longtime:
                if filename:
                    self.logger.info("Diff of %s taking a long time" %
                                     filename)
                else:
                    self.logger.info("Diff taking a long time")
                longtime = True
            elif now - start > 30:
                if filename:
                    self.logger.error("Diff of %s took too long; giving up" %
                                      filename)
                else:
                    self.logger.error("Diff took too long; giving up")
                return False
        return rv

    def Installpermissions(self, entry):
        """Install POSIX permissions"""
        if entry.get('perms') == None or \
           entry.get('owner') == None or \
           entry.get('group') == None:
            self.logger.error('Entry %s not completely specified. '
                              'Try running bcfg2-lint.' % (entry.get('name')))
            return False
        plist = [entry.get('name')]
        if entry.get('recursive') in ['True', 'true']:
            # verify ownership information recursively
            owner = normUid(entry, logger=self.logger)
            group = normGid(entry, logger=self.logger)

            for root, dirs, files in os.walk(entry.get('name')):
                for p in dirs + files:
                    path = os.path.join(root, p)
                    pstat = os.stat(path)
                    if owner != pstat.st_uid or group != pstat.st_gid:
                        # owner mismatch for path
                        plist.append(path)
        try:
            for p in plist:
                os.chown(p,
                         normUid(entry, logger=self.logger),
                         normGid(entry, logger=self.logger))
                os.chmod(p, calcPerms(stat.S_IFDIR, entry.get('perms')))
            return True
        except (OSError, KeyError):
            self.logger.error('Permission fixup failed for %s' % \
                              (entry.get('name')))
            return False

    def Verifysymlink(self, entry, _):
        """Verify Path type='symlink' entry."""
        if entry.get('to') == None:
            self.logger.error('Entry %s not completely specified. '
                              'Try running bcfg2-lint.' % \
                              (entry.get('name')))
            return False
        try:
            sloc = os.readlink(entry.get('name'))
            if sloc == entry.get('to'):
                return True
            self.logger.debug("Symlink %s points to %s, should be %s" % \
                              (entry.get('name'), sloc, entry.get('to')))
            entry.set('current_to', sloc)
            entry.set('qtext', "Link %s to %s? [y/N] " % (entry.get('name'),
                                                   entry.get('to')))
            return False
        except OSError:
            entry.set('current_exists', 'false')
            entry.set('qtext', "Link %s to %s? [y/N] " % (entry.get('name'),
                                                   entry.get('to')))
            return False

    def Installsymlink(self, entry):
        """Install Path type='symlink' entry."""
        if entry.get('to') == None:
            self.logger.error('Entry %s not completely specified. '
                              'Try running bcfg2-lint.' % \
                              (entry.get('name')))
            return False
        self.logger.info("Installing symlink %s" % (entry.get('name')))
        if os.path.lexists(entry.get('name')):
            try:
                fmode = os.lstat(entry.get('name'))[stat.ST_MODE]
                if stat.S_ISREG(fmode) or stat.S_ISLNK(fmode):
                    self.logger.debug("Non-directory entry already exists at "
                                      "%s. Unlinking entry." % \
                                      (entry.get('name')))
                    os.unlink(entry.get('name'))
                elif stat.S_ISDIR(fmode):
                    self.logger.debug("Directory already exists at %s" %\
                                      (entry.get('name')))
                    self.cmd.run("mv %s/ %s.bak" % \
                                 (entry.get('name'),
                                  entry.get('name')))
                else:
                    os.unlink(entry.get('name'))
            except OSError:
                self.logger.info("Symlink %s cleanup failed" %\
                                 (entry.get('name')))
        try:
            os.symlink(entry.get('to'), entry.get('name'))
            return True
        except OSError:
            return False

    def InstallPath(self, entry):
        """Dispatch install to the proper method according to type"""
        ret = getattr(self, 'Install%s' % entry.get('type'))
        return ret(entry)

    def VerifyPath(self, entry, _):
        """Dispatch verify to the proper method according to type"""
        ret = getattr(self, 'Verify%s' % entry.get('type'))
        return ret(entry, _)