ansible/library/file

#!/usr/bin/python
# -*- coding: utf-8 -*-

# (c) 2012, Michael DeHaan <michael.dehaan@gmail.com>
#
# This file is part of Ansible
#
# Ansible 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, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible 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 Ansible.  If not, see <http://www.gnu.org/licenses/>.

import shutil
import stat
import grp
import pwd
try:
    import selinux
    HAVE_SELINUX=True
except ImportError:
    HAVE_SELINUX=False

DOCUMENTATION = '''
---
module: file
short_description: Sets attributes of files
description: 
     - Sets attributes of files, symlinks, and directories, or removes
       files/symlinks/directories. Many other modules support the same options as
       the file module - including M(copy), M(template), and M(assmeble).
options:
  dest:
    description:
      - defines the file being managed, unless when used with I(state=link), and then sets the destination to create a symbolic link to using I(src)
    required: true
    default: []
    aliases: []
  state:
    description:
      - If C(directory), all immediate subdirectories will be created if they
        do not exist. If C(file), the file will NOT be created if it does not
        exist, see the M(copy) or M(template) module if you want that behavior.
        If C(link), the symbolic link will be created or changed. If C(absent),
        directories will be recursively deleted, and files or symlinks will be
        unlinked.
    required: false
    default: file
    choices: [ file, link, directory, absent ]
  mode:
    required: false
    default: null
    choices: []
    description:
      - mode the file or directory should be, such as 0644 as would be fed to
  owner:
    required: false
    default: null
    choices: []
    description:
      - name of the user that should own the file/directory, as would be fed to I(chown)
  group:
    required: false
    default: null
    choices: []
    description:
      - name of the group that should own the file/directory, as would be fed to I(chown)
  src:
    required: false
    default: null
    choices: []
    description:
      - path of the file to link to (applies only to C(state=link)).
  seuser:
    required: false
    default: null
    choices: []
    description:
      - user part of SELinux file context. Will default to system policy, if
        applicable. If set to C(_default), it will use the C(user) portion of the
        the policy if available
  serole:
    required: false
    default: null
    choices: []
    description:
      - role part of SELinux file context, C(_default) feature works as for I(seuser).
  setype:
    required: false
    default: null
    choices: []
    description:
      - type part of SELinux file context, C(_default) feature works as for I(seuser).
  selevel:
    required: false
    default: "s0"
    choices: []
    description:
      - level part of the SELinux file context. This is the MLS/MCS attribute,
        sometimes known as the C(range). C(_default) feature works as for
        I(seuser).
  context:
    required: false
    default: null
    choices: [ "default" ]
    description:
      - accepts only C(default) as value. This will restore a file's SELinux context
        in the policy. Does nothing if no default value is available.
  force:
    required: false
    default: null
    choices: []
    description:
      - force is required when changing an existing file to a directory, or a link to a directory, and so on.  Use this with caution.
examples:
   - code: file path=/etc/foo.conf owner=foo group=foo mode=0644
     description: Example from Ansible Playbooks
   - code: file src=/file/to/link/to dest=/path/to/symlink owner=foo group=foo state=link
notes:
    - See also M(copy), M(template), M(assemble)
requirements: [ ]
author: Michael DeHaan
'''

def add_path_info(kwargs):
    path = kwargs['path']
    if os.path.exists(path):
        (user, group) = user_and_group(path)
        kwargs['owner']  = user
        kwargs['group'] = group
        st = os.stat(path)
        kwargs['mode']  = oct(stat.S_IMODE(st[stat.ST_MODE]))
        # secontext not yet supported
        if os.path.islink(path):
            kwargs['state'] = 'link'
        elif os.path.isdir(path):
            kwargs['state'] = 'directory'
        else:
            kwargs['state'] = 'file'
        if HAVE_SELINUX and selinux_enabled():
            kwargs['secontext'] = ':'.join(selinux_context(path))
    else:
        kwargs['state'] = 'absent'
    return kwargs

def module_exit_json(**kwargs):
    add_path_info(kwargs)
    module.exit_json(**kwargs)

def module_fail_json(**kwargs):
    add_path_info(kwargs)
    module.fail_json(**kwargs)

# Detect whether using selinux that is MLS-aware.
# While this means you can set the level/range with
# selinux.lsetfilecon(), it may or may not mean that you
# will get the selevel as part of the context returned
# by selinux.lgetfilecon().
def selinux_mls_enabled():
    if not HAVE_SELINUX:
        return False
    if selinux.is_selinux_mls_enabled() == 1:
        return True
    else:
        return False

def selinux_enabled():
    if not HAVE_SELINUX:
        return False
    if selinux.is_selinux_enabled() == 1:
        return True
    else:
        return False

# Determine whether we need a placeholder for selevel/mls
def selinux_initial_context():
    context = [None, None, None]
    if selinux_mls_enabled():
        context.append(None)
    return context

# If selinux fails to find a default, return an array of None
def selinux_default_context(path, mode=0):
    context = selinux_initial_context()
    if not HAVE_SELINUX or not selinux_enabled():
        return context
    try:
        ret = selinux.matchpathcon(path, mode)
    except OSError:
        return context
    if ret[0] == -1:
        return context
    context = ret[1].split(':')
    return context

def selinux_context(path):
    context = selinux_initial_context()
    if not HAVE_SELINUX or not selinux_enabled():
        return context
    try:
        ret = selinux.lgetfilecon(path)
    except:
        module_fail_json(path=path, msg='failed to retrieve selinux context')
    if ret[0] == -1:
        return context
    context = ret[1].split(':')
    return context

# ===========================================
# support functions

def user_and_group(filename):
    st = os.stat(filename)
    uid = st.st_uid
    gid = st.st_gid
    try:
        user = pwd.getpwuid(uid)[0]
    except KeyError:
        user = str(uid)
    try:
        group = grp.getgrgid(gid)[0]
    except KeyError:
        group = str(gid)
    return (user, group)

def set_context_if_different(path, context, changed):
    if not HAVE_SELINUX or not selinux_enabled():
        return changed
    cur_context = selinux_context(path)
    new_context = list(cur_context)
    # Iterate over the current context instead of the
    # argument context, which may have selevel.
    for i in range(len(cur_context)):
        if context[i] is not None and context[i] != cur_context[i]:
            new_context[i] = context[i]
    if cur_context != new_context:
        try:
            rc = selinux.lsetfilecon(path, ':'.join(new_context))
        except OSError:
            module_fail_json(path=path, msg='invalid selinux context')
        if rc != 0:
            module_fail_json(path=path, msg='set selinux context failed')
        changed = True
    return changed

def set_owner_if_different(path, owner, changed):
    if owner is None:
        return changed
    user, group = user_and_group(path)
    if owner != user:
        try:
            uid = pwd.getpwnam(owner).pw_uid
        except KeyError:
            module_fail_json(path=path, msg='chown failed: failed to look up user %s' % owner)
        try:
            os.chown(path, uid, -1)
        except OSError:
            module_fail_json(path=path, msg='chown failed')
        return True

    return changed

def set_group_if_different(path, group, changed):
    if group is None:
        return changed
    old_user, old_group = user_and_group(path)
    if old_group != group:
        try:
            gid = grp.getgrnam(group).gr_gid
        except KeyError:
            module_fail_json(path=path, msg='chgrp failed: failed to look up group %s' % group)
        try:
            os.chown(path, -1, gid)
        except OSError:
            module_fail_json(path=path, msg='chgrp failed')
        return True
    return changed

def set_mode_if_different(path, mode, changed):
    if mode is None:
        return changed
    try:
        # FIXME: support English modes
        mode = int(mode, 8)
    except Exception, e:
        module_fail_json(path=path, msg='mode needs to be something octalish', details=str(e))

    st = os.stat(path)
    prev_mode = stat.S_IMODE(st[stat.ST_MODE])

    if prev_mode != mode:
        # FIXME: comparison against string above will cause this to be executed
        # every time
        try:
            os.chmod(path, mode)
        except Exception, e:
            module_fail_json(path=path, msg='chmod failed', details=str(e))
 
        st = os.stat(path)
        new_mode = stat.S_IMODE(st[stat.ST_MODE])

        if new_mode != prev_mode:
            return True
    return changed


def rmtree_error(func, path, exc_info):
    module_fail_json(path=path, msg='failed to remove directory')

def main():

    # FIXME: pass this around, should not use global
    global module

    module = AnsibleModule(
        check_invalid_arguments = False,
        argument_spec = dict(
            state = dict(choices=['file','directory','link','absent'], default='file'),
            path  = dict(aliases=['dest', 'name'], required=True),
            src   = dict(),
            force = dict(default='no', choices=['yes', 'no']),
            mode  = dict(),
            owner = dict(),
            group = dict(),
            seuser = dict(),
            serole = dict(),
            selevel = dict(),
            setype = dict(),
        )
    )

    params = module.params
    state  = params['state']
    path   = os.path.expanduser(params['path'])

    # source is both the source of a symlink or an informational passing of the src for a template module
    # or copy module, even if this module never uses it, it is needed to key off some things

    src    = params.get('src', None)
    if src:
        src = os.path.expanduser(src)
    force = module.boolean(params['force'])

    if src is not None and os.path.isdir(path):
        params['path'] = path = os.path.join(path, os.path.basename(src))

    mode   = params.get('mode', None)
    owner  = params.get('owner', None)
    group  = params.get('group', None)

    # selinux related options
    seuser    = params.get('seuser', None)
    serole    = params.get('serole', None)
    setype    = params.get('setype', None)
    selevel   = params.get('serange', 's0')
    secontext = [seuser, serole, setype]
    if selinux_mls_enabled():
        secontext.append(selevel)

    default_secontext = selinux_default_context(path)
    for i in range(len(default_secontext)):
        if i is not None and secontext[i] == '_default':
            secontext[i] = default_secontext[i]

    if state == 'link' and (src is None or path is None):
        module_fail_json(msg='src and dest are required for "link" state')
    elif path is None:
        module_fail_json(msg='path is required')

    changed = False

    prev_state = 'absent'

    if os.path.lexists(path):
        if os.path.islink(path):
            prev_state = 'link'
        elif os.path.isdir(path):
            prev_state = 'directory'
        else:
            prev_state = 'file'

    if prev_state != 'absent' and state == 'absent':
        try:
            if prev_state == 'directory':
                if os.path.islink(path):
                    os.unlink(path)
                else:
                    shutil.rmtree(path, ignore_errors=False, onerror=rmtree_error)
            else:
                os.unlink(path)
        except Exception, e:
            module_fail_json(path=path, msg=str(e))
        module_exit_json(path=path, changed=True)

    if prev_state != 'absent' and prev_state != state and not force:
        module_fail_json(path=path, msg='refusing to convert between %s and %s for %s' % (prev_state, state, src))

    if prev_state == 'absent' and state == 'absent':
        module_exit_json(path=path, changed=False)

    if state == 'file':

        if prev_state != 'file':
            module_fail_json(path=path, msg='file (%s) does not exist, use copy or template module to create' % path) 

        # set modes owners and context as needed
        changed = set_context_if_different(path, secontext, changed)
        changed = set_owner_if_different(path, owner, changed)
        changed = set_group_if_different(path, group, changed)
        changed = set_mode_if_different(path, mode, changed)

        module_exit_json(path=path, changed=changed)

    elif state == 'directory':

        if prev_state == 'absent':
            os.makedirs(path)
            changed = True
        elif prev_state != 'directory' and force:
            try:
                os.unlink(path)
            except Exception, e:
                module_fail_json(path=path, msg=str(e))
            os.makedirs(path)
            changed = True

        # set modes owners and context as needed
        changed = set_context_if_different(path, secontext, changed)
        changed = set_owner_if_different(path, owner, changed)
        changed = set_group_if_different(path, group, changed)
        changed = set_mode_if_different(path, mode, changed)

        module_exit_json(path=path, changed=changed)

    elif state == 'link':

        if os.path.isabs(src):
            abs_src = src
        else:
            module.fail_json(msg="absolute paths are required")
        if not os.path.exists(abs_src):
            module_fail_json(path=path, src=src, msg='src file does not exist')

        if prev_state == 'absent':
            os.symlink(src, path)
            changed = True
        elif prev_state != 'link' and force:
            try:
                if os.path.isfile(path):
                    os.unlink(path)
                else:
                    shutil.rmtree(path, ignore_errors=False, onerror=rmtree_error)
            except Exception, e:
                module_fail_json(path=path, msg=str(e))
            os.symlink(src, path)
            changed = True
        elif prev_state == 'link':
            old_src = os.readlink(path)
            if not os.path.isabs(old_src):
                old_src = os.path.join(os.path.dirname(path), old_src)
            if old_src != src:
                os.unlink(path)
                os.symlink(src, path)
                changed = True
        else:
            module_fail_json(dest=path, src=src, msg='unexpected position reached')

        # set modes owners and context as needed
        changed = set_context_if_different(path, secontext, changed)
        changed = set_owner_if_different(path, owner, changed)
        changed = set_group_if_different(path, group, changed)
        changed = set_mode_if_different(path, mode, changed)

        module.exit_json(dest=path, src=src, changed=changed)

    module_fail_json(path=path, msg='unexpected position reached')

# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()