From c7e4b037a79c9c9d701d5aa7fbdadfabfb1322ea Mon Sep 17 00:00:00 2001
From: Balazs Lecz <leczb@google.com>
Date: Wed, 21 Apr 2010 10:47:48 +0100
Subject: [PATCH] Use ints instead of strings to represent user-ids
Signed-off-by: Balazs Lecz <leczb@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>
---
lib/uidpool.py | 35 ++++++++++++++++++++++++++---------
1 file changed, 26 insertions(+), 9 deletions(-)
diff --git a/lib/uidpool.py b/lib/uidpool.py
index 80e7807c5..aba5febe6 100644
--- a/lib/uidpool.py
+++ b/lib/uidpool.py
@@ -182,6 +182,9 @@ def ExpandUidPool(uid_pool):
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)
@@ -218,7 +221,7 @@ class LockedUid(object):
def GetUid(self):
return self._uid
- def __str__(self):
+ def AsStr(self):
return "%s" % self._uid
@@ -255,6 +258,7 @@ def RequestUnusedUid(all_uids):
<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
@@ -269,12 +273,20 @@ def RequestUnusedUid(all_uids):
# 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(constants.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:
@@ -330,12 +342,16 @@ def ReleaseUid(uid):
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(constants.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):
@@ -344,17 +360,18 @@ 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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