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community.general/library/system/sysctl
James Cammarata 5110b2d440 Slight refactorization of the sysctl module 
* Added in support for freebsd-style sysctl commands
* Replaced some functionality that was provided by module_common
* Simplified some logic in a couple of places (ie, not checking
  a split with len() but instead limiting the split to 1)

Fixes #3380
2013-09-11 13:15:17 -05:00

341 lines
12 KiB
Python
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#!/usr/bin/python
# -*- coding: utf-8 -*-
# (c) 2012, David "DaviXX" CHANIAL <david.chanial@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/>.
#
DOCUMENTATION = '''
---
module: sysctl
short_description: Permit to handle sysctl.conf entries
description:
- This module manipulates sysctl entries and performs a I(/sbin/sysctl -p) after changing them.
version_added: "1.0"
options:
name:
description:
- this is the short path, decimal separated, to the sysctl entry
required: true
default: null
aliases: [ 'key' ]
value:
description:
- set the sysctl value to this entry
required: false
default: null
aliases: [ 'val' ]
state:
description:
- whether the entry should be present or absent
choices: [ "present", "absent" ]
default: present
checks:
description:
- if C(checks)=I(none) no smart/facultative checks will be made
- if C(checks)=I(before) some checks performed before any update (ie. does the sysctl key is writable ?)
- if C(checks)=I(after) some checks performed after an update (ie. does kernel give back the set value ?)
- if C(checks)=I(both) all the smart checks I(before and after) are performed
choices: [ "none", "before", "after", "both" ]
default: both
reload:
description:
- if C(reload=yes), performs a I(/sbin/sysctl -p) if the C(sysctl_file) is updated
- if C(reload=no), does not reload I(sysctl) even if the C(sysctl_file) is updated
choices: [ "yes", "no" ]
default: "yes"
sysctl_file:
description:
- specifies the absolute path to C(sysctl.conf), if not /etc/sysctl.conf
required: false
default: /etc/sysctl.conf
notes: []
requirements: []
author: David "DaviXX" CHANIAL <david.chanial@gmail.com>
'''
EXAMPLES = '''
# Set vm.swappiness to 5 in /etc/sysctl.conf
- sysctl: name=vm.swappiness value=5 state=present
# Remove kernel.panic entry from /etc/sysctl.conf
- sysctl: name=kernel.panic state=absent sysctl_file=/etc/sysctl.conf
# Set kernel.panic to 3 in /tmp/test_sysctl.conf, check if the sysctl key
# seems writable, but do not reload sysctl, and do not check kernel value
# after (not needed, because the real /etc/sysctl.conf was not updated)
- sysctl: name=kernel.panic value=3 sysctl_file=/tmp/test_sysctl.conf check=before reload=no
'''
# ==============================================================
import os
import tempfile
import re
# ==============================================================
def reload_sysctl(module, **sysctl_args):
# update needed ?
if not sysctl_args['reload']:
return 0, ''
# do it
if get_platform().lower() == 'freebsd':
# freebsd doesn't support -p, so reload the sysctl service
rc,out,err = module.run_command('/etc/rc.d/sysctl reload')
else:
# system supports reloading via the -p flag to sysctl, so we'll use that
sysctl_cmd = module.get_bin_path('sysctl', required=True)
rc,out,err = module.run_command([sysctl_cmd, '-p', sysctl_args['sysctl_file']])
return rc,out+err
# ==============================================================
def write_sysctl(module, lines, **sysctl_args):
# open a tmp file
fd, tmp_path = tempfile.mkstemp('.conf', '.ansible_m_sysctl_', os.path.dirname(sysctl_args['sysctl_file']))
f = open(tmp_path,"w")
try:
for l in lines:
f.write(l)
except IOError, e:
module.fail_json(msg="Failed to write to file %s: %s" % (tmp_path, str(e)))
f.flush()
f.close()
# replace the real one
module.atomic_move(tmp_path, sysctl_args['sysctl_file'])
# end
return sysctl_args
# ==============================================================
def sysctl_args_expand(**sysctl_args):
if get_platform().lower() == 'freebsd':
# FreeBSD does not use the /proc file system, and instead
# just uses the sysctl command to set the values
sysctl_args['key_path'] = None
else:
sysctl_args['key_path'] = sysctl_args['name'].replace('.' ,'/')
sysctl_args['key_path'] = '/proc/sys/' + sysctl_args['key_path']
return sysctl_args
# ==============================================================
def sysctl_args_collapse(**sysctl_args):
# go ahead
if sysctl_args.get('key_path') is not None:
del sysctl_args['key_path']
if sysctl_args['state'] == 'absent' and 'value' in sysctl_args:
del sysctl_args['value']
# end
return sysctl_args
# ==============================================================
def sysctl_check(module, current_step, **sysctl_args):
# no smart checks at this step ?
if sysctl_args['checks'] == 'none':
return 0, ''
if current_step == 'before' and sysctl_args['checks'] not in ['before', 'both']:
return 0, ''
if current_step == 'after' and sysctl_args['checks'] not in ['after', 'both']:
return 0, ''
# checking coherence
if sysctl_args['state'] == 'absent' and sysctl_args['value'] is not None:
return 1, 'value=x must not be supplied when state=absent'
if sysctl_args['state'] == 'present' and sysctl_args['value'] is None:
return 1, 'value=x must be supplied when state=present'
if not sysctl_args['reload'] and sysctl_args['checks'] in ['after', 'both']:
return 1, 'checks cannot be set to after or both if reload=no'
if sysctl_args['key_path'] is not None:
# getting file stat
if not os.access(sysctl_args['key_path'], os.F_OK):
return 1, 'key_path is not an existing file, key %s seems invalid' % sysctl_args['key_path']
if not os.access(sysctl_args['key_path'], os.R_OK):
return 1, 'key_path is not a readable file, key seems to be uncheckable'
# checks before
if current_step == 'before' and sysctl_args['checks'] in ['before', 'both']:
if sysctl_args['key_path'] is not None and not os.access(sysctl_args['key_path'], os.W_OK):
return 1, 'key_path is not a writable file, key seems to be read only'
return 0, ''
# checks after
if current_step == 'after' and sysctl_args['checks'] in ['after', 'both']:
if sysctl_args['value'] is not None:
if sysctl_args['key_path'] is not None:
# reading the virtual file
f = open(sysctl_args['key_path'],'r')
output = f.read()
f.close()
else:
# we're on a system without /proc (ie. freebsd), so just
# use the sysctl command to get the currently set value
sysctl_cmd = module.get_bin_path('sysctl', required=True)
rc,output,stderr = module.run_command("%s -n %s" % (sysctl_cmd, sysctl_args['name']))
if rc != 0:
return 1, 'failed to lookup the value via the sysctl command'
output = output.strip(' \t\n\r')
output = re.sub(r'\s+', ' ', output)
# normal case, found value must be equal to the submitted value, and
# we compare the exploded values to handle any whitepsace differences
if output.split() != sysctl_args['value'].split():
return 1, 'key seems not set to value even after update/sysctl, founded : <%s>, wanted : <%s>' % (output, sysctl_args['value'])
return 0, ''
else:
# no value was supplied, so we're checking to make sure
# the associated name is absent. We just fudge this since
# the sysctl isn't really gone, just removed from the conf
# file meaning it will be whatever the system default is
return 0, ''
# weird end
return 1, 'unexpected position reached'
# ==============================================================
# main
def main():
# defining module
module = AnsibleModule(
argument_spec = dict(
name = dict(aliases=['key'], required=True),
value = dict(aliases=['val'], required=False),
state = dict(default='present', choices=['present', 'absent']),
checks = dict(default='both', choices=['none', 'before', 'after', 'both']),
reload = dict(default=True, type='bool'),
sysctl_file = dict(default='/etc/sysctl.conf')
)
)
# defaults
sysctl_args = {
'changed': False,
'name': module.params['name'],
'state': module.params['state'],
'checks': module.params['checks'],
'reload': module.params['reload'],
'value': module.params.get('value'),
'sysctl_file': module.params['sysctl_file']
}
# prepare vars
sysctl_args = sysctl_args_expand(**sysctl_args)
if get_platform().lower() == 'freebsd':
# freebsd does not like spaces around the equal sign
pattern = "%s=%s\n"
else:
pattern = "%s = %s\n"
new_line = pattern % (sysctl_args['name'], sysctl_args['value'])
to_write = []
founded = False
# make checks before act
res,msg = sysctl_check(module, 'before', **sysctl_args)
if res != 0:
module.fail_json(msg='checks_before failed with: ' + msg)
if not os.access(sysctl_args['sysctl_file'], os.W_OK):
try:
f = open(sysctl_args['sysctl_file'],'w')
f.close()
except IOError, e:
module.fail_json(msg='unable to create supplied sysctl file (destination directory probably missing)')
# reading the file
for line in open(sysctl_args['sysctl_file'], 'r').readlines():
if not line.strip():
to_write.append(line)
continue
if line.strip().startswith('#'):
to_write.append(line)
continue
# write line if not the one searched
ld = {}
ld['name'], ld['val'] = line.split('=',1)
ld['name'] = ld['name'].strip()
if ld['name'] != sysctl_args['name']:
to_write.append(line)
continue
# should be absent ?
if sysctl_args['state'] == 'absent':
# not writing the founded line
# mark as changed
sysctl_args['changed'] = True
# should be present
if sysctl_args['state'] == 'present':
# is the founded line equal to the wanted one ?
ld['val'] = ld['val'].strip()
if ld['val'] == sysctl_args['value']:
# line is equal, writing it without update (but cancel repeats)
if sysctl_args['changed'] == False and founded == False:
to_write.append(line)
founded = True
else:
# update the line (but cancel repeats)
if sysctl_args['changed'] == False and founded == False:
to_write.append(new_line)
sysctl_args['changed'] = True
continue
# if not changed, but should be present, so we have to add it
if sysctl_args['state'] == 'present' and sysctl_args['changed'] == False and founded == False:
to_write.append(new_line)
sysctl_args['changed'] = True
# has changed ?
res = 0
if sysctl_args['changed'] == True:
sysctl_args = write_sysctl(module, to_write, **sysctl_args)
res,msg = reload_sysctl(module, **sysctl_args)
# make checks after act
res,msg = sysctl_check(module, 'after', **sysctl_args)
if res != 0:
module.fail_json(msg='checks_after failed with: ' + msg)
# look at the next link to avoid this workaround
# https://groups.google.com/forum/?fromgroups=#!topic/ansible-project/LMY-dwF6SQk
changed = sysctl_args['changed']
del sysctl_args['changed']
# end
sysctl_args = sysctl_args_collapse(**sysctl_args)
module.exit_json(changed=changed, **sysctl_args)
sys.exit(0)
# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()
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