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# Copyright 2010, 2011 Lars Wirzenius
#
# 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
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
import logging
import sys
import tracing
import ttystatus
import larch
class Error(larch.Error):
def __init__(self, msg):
self.msg = 'Assertion failed: %s' % msg
class WorkItem(object):
'''A work item for fsck.
Subclass can optionally set the ``name`` attribute; the class name
is used by default.
'''
def __str__(self):
if hasattr(self, 'name'):
return self.name
else:
return self.__class__.__name__
def do(self):
pass
def warning(self, msg):
self.fsck.warning('warning: %s: %s' % (self.name, msg))
def error(self, msg):
self.fsck.error('ERROR: %s: %s' % (self.name, msg))
def get_node(self, node_id):
try:
return self.fsck.forest.node_store.get_node(node_id)
except larch.NodeMissing:
self.error('node %s is missing' % node_id)
class CheckNode(WorkItem):
def __init__(self, fsck, node_id):
self.fsck = fsck
self.node_id = node_id
self.name = 'node %s' % node_id
def do(self):
tracing.trace('checking node %s' % self.node_id)
node = self.get_node(self.node_id)
if node:
if type(node) not in [larch.IndexNode, larch.LeafNode]:
self.error('node must be an index or leaf node')
return
keys = node.keys()
if self.fsck.forest.node_store.get_refcount(node.id) <= 0:
self.warning('node refcount must be > 0')
if not len(keys):
self.warning('node must have keys')
if sorted(keys) != keys:
self.error('node keys must be sorted')
if sorted(set(keys)) != keys:
self.error('node keys must be unique')
encoded = self.fsck.forest.node_store.codec.encode(node)
if len(encoded) > self.fsck.forest.node_store.node_size:
self.warning('node is too large')
if len(encoded) == 0:
self.warning('node has zero size when encoded')
if self.fsck.fix and type(node) == larch.IndexNode:
tracing.trace('checking and fixing index node %s' %
self.node_id)
keys = []
for key in node:
child_id = node[key]
if self.get_node(child_id):
keys.append(key)
else:
tracing.trace('child %s is missing' % child_id)
if keys != node.keys():
tracing.trace('Replacing index node %s with fixed copy' %
self.node_id)
new_node = larch.IndexNode(node.id, keys,
[node[k] for k in keys])
self.fsck.forest.node_store.put_node(new_node)
tracing.trace('fixed it: %s' % new_node.keys())
class CheckRoot(WorkItem):
def __init__(self, fsck, root_id):
self.fsck = fsck
self.root_id = root_id
self.name = 'root node %s' % root_id
def do(self):
tracing.trace('checking root node %s' % self.root_id)
node = self.get_node(self.root_id)
if node:
if self.fsck.forest.node_store.get_refcount(self.root_id) != 1:
self.warning('root refcount must be 1')
if type(node) != larch.IndexNode:
self.error('root must be an index node')
else:
self.error('missing root node %s' % self.root_id)
class CheckRecursively(WorkItem):
def __init__(self, fsck, root_id, seen):
self.fsck = fsck
self.root_id = root_id
self.name = 'tree %s' % root_id
self.seen = seen
def do(self):
tracing.trace('checking recursive from root node %s' % self.root_id)
for node, minkey, maxkey in self.walk(self.root_id):
if node.id not in self.seen:
tracing.trace('checking node %s' % node.id)
self.seen.add(node.id)
keys = node.keys()
if keys:
if keys[0] < minkey:
self.error('node %s: first key is too small' % node.id)
if keys[-1] > maxkey:
self.error('node %s: last key is too large' % node.id)
def walk(self, root_id):
def walker(node_id, minkey, maxkey, expected_type):
expected_child = None
node = self.get_node(node_id)
if node:
yield node, minkey, maxkey
if type(node) == larch.IndexNode:
tracing.trace('recursively found index node %s' % node.id)
keys = node.keys()
tracing.trace('keys: %s' % repr(keys))
for i, key in enumerate(keys):
child_id = node[key]
if i + 1 < len(keys):
next_key = keys[i+1]
else:
next_key = maxkey
if expected_child is None:
child = self.get_node(child_id)
if child:
expected_child = type(child)
for x in walker(child_id, key, next_key,
expected_child):
yield x
else:
if expected_type == larch.IndexNode:
self.error('cannot find index node %s' % node_id)
elif expected_type == larch.LeafNode:
self.error('cannot find leaf node %s' % node_id)
else:
self.error('cannot find node of unknown type %s' % node_id)
ns = self.fsck.forest.node_store
tree_minkey = chr(0) * ns.codec.key_bytes
tree_maxkey = chr(255) * ns.codec.key_bytes
for x in walker(root_id, tree_minkey, tree_maxkey, larch.IndexNode):
yield x
class CheckExtraNodes(WorkItem):
def __init__(self, fsck):
self.fsck = fsck
self.seen = set()
self.name = 'extra nodes'
def do(self):
tracing.trace('checking for extra nodes')
for node_id in self.fsck.forest.node_store.list_nodes():
if node_id not in self.seen:
self.warning('node %d is not part of the tree' % node_id)
class CommitForest(WorkItem):
def __init__(self, fsck):
self.fsck = fsck
self.name = 'committing fixes'
def do(self):
tracing.trace('committing changes to forest')
self.fsck.forest.commit()
class Fsck(object):
'''Verify internal consistency of a larch.Forest.'''
def __init__(self, forest, warning, error, fix):
self.forest = forest
self.warning = warning
self.error = error
self.fix = fix
def find_work(self):
for node_id in self.forest.node_store.list_nodes():
tracing.trace('found node %s' % node_id)
yield CheckNode(self, node_id)
for tree in self.forest.trees:
yield CheckRoot(self, tree.root.id)
extra = CheckExtraNodes(self)
for tree in self.forest.trees:
yield CheckRecursively(self, tree.root.id, extra.seen)
yield extra
if self.fix:
yield CommitForest(self)
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