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Fixed special RefreshLock logic as used by the bridge extensions
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This implied moving code, now all lock setting logic is in a single function
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@glpatcern
glpatcern committed May 4, 2022
1 parent 03b6395 commit 535ae76
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Showing 2 changed files with 100 additions and 105 deletions.
110 changes: 100 additions & 10 deletions src/core/wopi.py
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Original file line number Diff line number Diff line change
Expand Up @@ -156,29 +156,119 @@ def setLock(fileid, reqheaders, acctok):
lock = reqheaders['X-WOPI-Lock']
oldLock = reqheaders.get('X-WOPI-OldLock')
validateTarget = reqheaders.get('X-WOPI-Validate-Target')
retrievedLock, _ = utils.retrieveWopiLock(fileid, op, lock, acctok)
retrievedLock, lockHolder = utils.retrieveWopiLock(fileid, op, lock, acctok)

try:
# validate that the underlying file is still there (it might have been moved/deleted)
statInfo = st.stat(acctok['endpoint'], acctok['filename'], acctok['userid'])
except IOError as e:
log.warning('msg="%s: target file not found any longer" filename="%s" token="%s" reason="%s"' %
(op.title(), acctok['filename'], flask.request.args['access_token'][-20:], e))
return utils.makeConflictResponse(op, 'External App', lock, oldLock, acctok['filename'],
'The file got moved or deleted')

# perform the required checks for the validity of the new lock
if op == 'REFRESH_LOCK' and not retrievedLock:
if validateTarget:
# this is an extension of the API: a REFRESH_LOCK without previous lock but with a Validate-Target header
# is allowed provided that the target file was last saved by WOPI and not overwritten by external actions,
# that is it must have a valid LASTSAVETIMEKEY xattr.
# XXX Note this currently works on EOS because of a "feature" (soon to be fixed) such that xattrs are not
# XXX preserved when saving a new version of a file. To be reviewed!
# is allowed provided that the target file was last saved by WOPI and not overwritten by external actions
# (cf. PutFile logic)
savetime = st.getxattr(acctok['endpoint'], acctok['filename'], acctok['userid'], utils.LASTSAVETIMEKEY)
if savetime and (not savetime.isdigit() or int(savetime) < int(statInfo['mtime'])):
savetime = None
else:
savetime = None
if not savetime or not savetime.isdigit():
if not savetime:
return utils.makeConflictResponse(op, None, lock, oldLock, acctok['filename'],
'The file was not locked' + ' and got modified' if validateTarget else '')

# LOCK or REFRESH_LOCK: atomically set the lock to the given one, including the expiration time,
# and return conflict response if the file was already locked
# now check "external" locks if required
if srv.config.get('general', 'detectexternallocks', fallback='True').upper() == 'TRUE' and \
os.path.splitext(acctok['filename'])[1] not in srv.nonofficetypes:
try:
# create a LibreOffice-compatible lock file for interoperability purposes, making sure to
# not overwrite any existing or being created lock
lockcontent = ',Collaborative Online Editor,%s,%s,WOPIServer;' % \
(srv.wopiurl, time.strftime('%d.%m.%Y %H:%M', time.localtime(time.time())))
st.writefile(acctok['endpoint'], utils.getLibreOfficeLockName(acctok['filename']), acctok['userid'],
lockcontent, None, islock=True)
except IOError as e:
if common.EXCL_ERROR in str(e):
# retrieve the LibreOffice-compatible lock just found
try:
retrievedlolock = next(st.readfile(acctok['endpoint'], utils.getLibreOfficeLockName(acctok['filename']),
acctok['userid'], None))
if isinstance(retrievedlolock, IOError):
raise retrievedlolock
retrievedlolock = retrievedlolock.decode()
# check that the lock is not stale
if datetime.strptime(retrievedlolock.split(',')[3], '%d.%m.%Y %H:%M').timestamp() + \
srv.config.getint('general', 'wopilockexpiration') < time.time():
retrievedlolock = 'WOPIServer'
except (IOError, StopIteration, IndexError, ValueError):
retrievedlolock = 'WOPIServer' # could not read the lock, assume it expired and take ownership
if 'WOPIServer' not in retrievedlolock:
# the file was externally locked, make this call fail
lockholder = retrievedlolock.split(',')[1] if ',' in retrievedlolock else ''
log.warning('msg="WOPI lock denied because of an existing LibreOffice lock" filename="%s" holder="%s"' %
(acctok['filename'], lockholder if lockholder else retrievedlolock))
reason = 'File locked by ' + ((lockholder + ' via LibreOffice') if lockholder else 'a LibreOffice user')
return utils.makeConflictResponse(op, 'External App', lock, oldLock, acctok['filename'], reason)
# else it's our previous lock or it had expired: all right, move on
else:
# any other error is logged but not raised as this is optimistically not blocking WOPI operations
# this includes the case of access denied (over)writing the LibreOffice lock because of accessing
# a single-file share
log.warning('msg="%s: unable to store LibreOffice-compatible lock" filename="%s" token="%s" reason="%s"' %
(op.title(), acctok['filename'], flask.request.args['access_token'][-20:], e))

try:
return utils.storeWopiLock(fileid, op, lock, oldLock, acctok)
# LOCK or REFRESH_LOCK: atomically set the lock to the given one, including the expiration time,
# and return conflict response if the file was already locked
st.setlock(acctok['endpoint'], acctok['filename'], acctok['userid'], acctok['appname'], utils.encodeLock(lock))
log.info('msg="%s" filename="%s" token="%s" lock="%s" result="success"' %
(op.title(), acctok['filename'], flask.request.args['access_token'][-20:], lock))

# on first lock, set an xattr with the current time for later conflicts checking
try:
st.setxattr(acctok['endpoint'], acctok['filename'], acctok['userid'], utils.LASTSAVETIMEKEY,
int(time.time()), utils.encodeLock(lock))
except IOError as e:
# not fatal, but will generate a conflict file later on, so log a warning
log.warning('msg="Unable to set lastwritetime xattr" user="%s" filename="%s" token="%s" reason="%s"' %
(acctok['userid'][-20:], acctok['filename'], flask.request.args['access_token'][-20:], e))
# also, keep track of files that have been opened for write: this is for statistical purposes only
# (cf. the GetLock WOPI call and the /wopi/cbox/open/list action)
if acctok['filename'] not in srv.openfiles:
srv.openfiles[acctok['filename']] = (time.asctime(), set([acctok['username']]))
else:
# the file was already opened but without lock: this happens on new files (cf. editnew action), just log
log.info('msg="First lock for new file" user="%s" filename="%s" token="%s"' %
(acctok['userid'][-20:], acctok['filename'], flask.request.args['access_token'][-20:]))
resp = flask.Response()
resp.status_code = http.client.OK
resp.headers['X-WOPI-ItemVersion'] = 'v%d' % statInfo['mtime']
return resp

except IOError as e:
# expected failures are handled in storeWopiLock
if common.EXCL_ERROR in str(e):
# another session was faster than us, or the file was already WOPI-locked:
# get the lock that was set
if not retrievedLock:
retrievedLock, lockHolder = utils.retrieveWopiLock(fileid, op, lock, acctok)
if retrievedLock and not utils.compareWopiLocks(retrievedLock, (oldLock if oldLock else lock)):
return utils.makeConflictResponse(op, retrievedLock, lock, oldLock, acctok['filename'],
'The file is locked by %s' %
(lockHolder if lockHolder != 'wopi' else 'another online editor'))
# else it's our own lock, refresh it and return
st.refreshlock(acctok['endpoint'], acctok['filename'], acctok['userid'], acctok['appname'], utils.encodeLock(lock))
log.info('msg="%s" filename="%s" token="%s" lock="%s" result="refreshed"' %
(op.title(), acctok['filename'], flask.request.args['access_token'][-20:], lock))
resp = flask.Response()
resp.status_code = http.client.OK
resp.headers['X-WOPI-ItemVersion'] = 'v%d' % statInfo['mtime']
return resp
# any other error is raised
log.error('msg="%s: unable to store WOPI lock" filename="%s" token="%s" lock="%s" reason="%s"' %
(op.title(), acctok['filename'], flask.request.args['access_token'][-20:], lock, e))
return IO_ERROR, http.client.INTERNAL_SERVER_ERROR
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95 changes: 0 additions & 95 deletions src/core/wopiutils.py
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Original file line number Diff line number Diff line change
Expand Up @@ -251,101 +251,6 @@ def _decodeLock(storedlock):
raise IOError(e)


def storeWopiLock(fileid, operation, lock, oldlock, acctok):
'''Stores the lock for a given file in the form of an encoded JSON string'''
try:
# validate that the underlying file is still there (it might have been moved/deleted)
statInfo = st.stat(acctok['endpoint'], acctok['filename'], acctok['userid'])
except IOError as e:
log.warning('msg="%s: target file not found any longer" filename="%s" token="%s" reason="%s"' %
(operation.title(), acctok['filename'], flask.request.args['access_token'][-20:], e))
return makeConflictResponse(operation, 'External App', lock, oldlock, acctok['filename'],
'The file got moved or deleted')

if srv.config.get('general', 'detectexternallocks', fallback='True').upper() == 'TRUE' and \
os.path.splitext(acctok['filename'])[1] not in srv.nonofficetypes:
try:
# create a LibreOffice-compatible lock file for interoperability purposes, making sure to
# not overwrite any existing or being created lock
lockcontent = ',Collaborative Online Editor,%s,%s,WOPIServer;' % \
(srv.wopiurl, time.strftime('%d.%m.%Y %H:%M', time.localtime(time.time())))
st.writefile(acctok['endpoint'], getLibreOfficeLockName(acctok['filename']), acctok['userid'],
lockcontent, None, islock=True)
except IOError as e:
if common.EXCL_ERROR in str(e):
# retrieve the LibreOffice-compatible lock just found
try:
retrievedlolock = next(st.readfile(acctok['endpoint'],
getLibreOfficeLockName(acctok['filename']), acctok['userid'], None))
if isinstance(retrievedlolock, IOError):
raise retrievedlolock
retrievedlolock = retrievedlolock.decode()
# check that the lock is not stale
if datetime.strptime(retrievedlolock.split(',')[3], '%d.%m.%Y %H:%M').timestamp() + \
srv.config.getint('general', 'wopilockexpiration') < time.time():
retrievedlolock = 'WOPIServer'
except (IOError, StopIteration, IndexError, ValueError):
retrievedlolock = 'WOPIServer' # could not read the lock, assume it expired and take ownership
if 'WOPIServer' not in retrievedlolock:
# the file was externally locked, make this call fail
lockholder = retrievedlolock.split(',')[1] if ',' in retrievedlolock else ''
log.warning('msg="WOPI lock denied because of an existing LibreOffice lock" filename="%s" holder="%s"' %
(acctok['filename'], lockholder if lockholder else retrievedlolock))
reason = 'File locked by ' + ((lockholder + ' via LibreOffice') if lockholder else 'a LibreOffice user')
return makeConflictResponse(operation, 'External App', lock, oldlock, acctok['filename'], reason)
# else it's our previous lock or it had expired: all right, move on
else:
# any other error is logged but not raised as this is optimistically not blocking WOPI operations
# this includes the case of access denied (over)writing the LibreOffice lock because of accessing a single-file share
log.warning('msg="%s: unable to store LibreOffice-compatible lock" filename="%s" token="%s" reason="%s"' %
(operation.title(), acctok['filename'], flask.request.args['access_token'][-20:], e))

try:
# now atomically store the lock
st.setlock(acctok['endpoint'], acctok['filename'], acctok['userid'], acctok['appname'], encodeLock(lock))
log.info('msg="%s" filename="%s" token="%s" lock="%s" result="success"' %
(operation.title(), acctok['filename'], flask.request.args['access_token'][-20:], lock))

# on first lock, set an xattr with the current time for later conflicts checking
try:
st.setxattr(acctok['endpoint'], acctok['filename'], acctok['userid'], LASTSAVETIMEKEY, int(time.time()), encodeLock(lock))
except IOError as e:
# not fatal, but will generate a conflict file later on, so log a warning
log.warning('msg="Unable to set lastwritetime xattr" user="%s" filename="%s" token="%s" reason="%s"' %
(acctok['userid'][-20:], acctok['filename'], flask.request.args['access_token'][-20:], e))
# also, keep track of files that have been opened for write: this is for statistical purposes only
# (cf. the GetLock WOPI call and the /wopi/cbox/open/list action)
if acctok['filename'] not in srv.openfiles:
srv.openfiles[acctok['filename']] = (time.asctime(), set([acctok['username']]))
else:
# the file was already opened but without lock: this happens on new files (cf. editnew action), just log
log.info('msg="First lock for new file" user="%s" filename="%s" token="%s"' %
(acctok['userid'][-20:], acctok['filename'], flask.request.args['access_token'][-20:]))
resp = flask.Response()
resp.status_code = http.client.OK
resp.headers['X-WOPI-ItemVersion'] = 'v%d' % statInfo['mtime']
return resp

except IOError as e:
if common.EXCL_ERROR in str(e):
# another session was faster than us, or the file was already WOPI-locked:
# get the lock that was set
retrievedLock, lockHolder = retrieveWopiLock(fileid, operation, lock, acctok)
if retrievedLock and not compareWopiLocks(retrievedLock, (oldlock if oldlock else lock)):
return makeConflictResponse(operation, retrievedLock, lock, oldlock, acctok['filename'],
'The file is locked by %s' % (lockHolder if lockHolder != 'wopi' else 'another online editor'))
# else it's our lock or it had expired, refresh it and return
st.refreshlock(acctok['endpoint'], acctok['filename'], acctok['userid'], acctok['appname'], encodeLock(lock))
log.info('msg="%s" filename="%s" token="%s" lock="%s" result="refreshed"' %
(operation.title(), acctok['filename'], flask.request.args['access_token'][-20:], lock))
resp = flask.Response()
resp.status_code = http.client.OK
resp.headers['X-WOPI-ItemVersion'] = 'v%d' % statInfo['mtime']
return resp
# any other error is raised
raise


def compareWopiLocks(lock1, lock2):
'''Compares two locks and returns True if they represent the same WOPI lock.
Officially, the comparison must be based on the locks' string representations, but because of
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