#
#
-# Copyright (C) 2010 Google Inc.
+# Copyright (C) 2010, 2012 Google Inc.
#
# 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
from ganeti import errors
from ganeti import constants
from ganeti import utils
+from ganeti import pathutils
def ParseUidPool(value, separator=None):
if n_elements > 2:
raise errors.OpPrereqError(
"Invalid user-id range definition. Only one hyphen allowed: %s"
- % boundaries)
+ % boundaries, errors.ECODE_INVAL)
try:
lower = int(boundaries[0])
except (ValueError, TypeError), err:
if uid_range not in uid_pool:
raise errors.OpPrereqError(
"User-id range to be removed is not found in the current"
- " user-id pool: %s" % uid_range, errors.ECODE_INVAL)
+ " user-id pool: %s" % str(uid_range), errors.ECODE_INVAL)
uid_pool.remove(uid_range)
"""
if lower == higher:
return str(lower)
+
return "%s-%s" % (lower, higher)
def _IsUidUsed(uid):
"""Check if there is any process in the system running with the given user-id
+ @type uid: integer
+ @param uid: the user-id to be checked.
+
"""
pgrep_command = [constants.PGREP, "-u", uid]
result = utils.RunCmd(pgrep_command)
# Release the exclusive lock and close the filedescriptor
self._lock.Close()
- def __str__(self):
+ def GetUid(self):
+ return self._uid
+
+ def AsStr(self):
return "%s" % self._uid
def RequestUnusedUid(all_uids):
"""Tries to find an unused uid from the uid-pool, locks it and returns it.
- Usage pattern:
+ Usage pattern
+ =============
- 1) When starting a process
+ 1. When starting a process::
from ganeti import ssconf
from ganeti import uidpool
# Get list of all user-ids in the uid-pool from ssconf
ss = ssconf.SimpleStore()
- uid_pool = uidpool.ParseUidPool(ss.GetUidPool(), separator="\n")
+ uid_pool = uidpool.ParseUidPool(ss.GetUidPool(), separator="\\n")
all_uids = set(uidpool.ExpandUidPool(uid_pool))
uid = uidpool.RequestUnusedUid(all_uids)
# Return the UID to the pool
uidpool.ReleaseUid(uid)
- 2) Stopping a process
+ 2. Stopping a process::
from ganeti import uidpool
<stop the process>
uidpool.ReleaseUid(uid)
+ @type all_uids: set of integers
@param all_uids: a set containing all the user-ids in the user-id pool
@return: a LockedUid object representing the unused uid. It's the caller's
responsibility to unlock the uid once an instance is started with
"""
# Create the lock dir if it's not yet present
try:
- utils.EnsureDirs([(constants.UIDPOOL_LOCKDIR, 0755)])
+ utils.EnsureDirs([(pathutils.UIDPOOL_LOCKDIR, 0755)])
except errors.GenericError, err:
raise errors.LockError("Failed to create user-id pool lock dir: %s" % err)
# Get list of currently used uids from the filesystem
try:
- taken_uids = set(os.listdir(constants.UIDPOOL_LOCKDIR))
- # Filter out spurious entries from the directory listing
- taken_uids = all_uids.intersection(taken_uids)
+ taken_uids = set()
+ for taken_uid in os.listdir(pathutils.UIDPOOL_LOCKDIR):
+ try:
+ taken_uid = int(taken_uid)
+ except ValueError, err:
+ # Skip directory entries that can't be converted into an integer
+ continue
+ taken_uids.add(taken_uid)
except OSError, err:
raise errors.LockError("Failed to get list of used user-ids: %s" % err)
+ # Filter out spurious entries from the directory listing
+ taken_uids = all_uids.intersection(taken_uids)
+
# Remove the list of used uids from the list of all uids
unused_uids = list(all_uids - taken_uids)
if not unused_uids:
# Create the lock file
# Note: we don't care if it exists. Only the fact that we can
# (or can't) lock it later is what matters.
- uid_path = utils.PathJoin(constants.UIDPOOL_LOCKDIR, str(uid))
+ uid_path = utils.PathJoin(pathutils.UIDPOOL_LOCKDIR, str(uid))
lock = utils.FileLock.Open(uid_path)
except OSError, err:
raise errors.LockError("Failed to create lockfile for user-id %s: %s"
def ReleaseUid(uid):
"""This should be called when the given user-id is no longer in use.
+ @type uid: LockedUid or integer
+ @param uid: the uid to release back to the pool
+
"""
- # Make sure we release the exclusive lock, if there is any
- uid.Unlock()
+ if isinstance(uid, LockedUid):
+ # Make sure we release the exclusive lock, if there is any
+ uid.Unlock()
+ uid_filename = uid.AsStr()
+ else:
+ uid_filename = str(uid)
+
try:
- uid_path = utils.PathJoin(constants.UIDPOOL_LOCKDIR, str(uid))
+ uid_path = utils.PathJoin(pathutils.UIDPOOL_LOCKDIR, uid_filename)
os.remove(uid_path)
except OSError, err:
raise errors.LockError("Failed to remove user-id lockfile"
- " for user-id %s: %s" % (uid, err))
+ " for user-id %s: %s" % (uid_filename, err))
def ExecWithUnusedUid(fn, all_uids, *args, **kwargs):
This wrapper function provides a simple way to handle the requesting,
unlocking and releasing a user-id.
"fn" is called by passing a "uid" keyword argument that
- contains an unused user-id (as a string) selected from the set of user-ids
+ contains an unused user-id (as an integer) selected from the set of user-ids
passed in all_uids.
If there is an error while executing "fn", the user-id is returned
to the pool.
- @param fn: a callable
+ @param fn: a callable that accepts a keyword argument called "uid"
+ @type all_uids: a set of integers
@param all_uids: a set containing all user-ids in the user-id pool
"""
uid = RequestUnusedUid(all_uids)
- kwargs["uid"] = str(uid)
+ kwargs["uid"] = uid.GetUid()
try:
return_value = fn(*args, **kwargs)
except:
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