我在 Python 中遇到这个非致命错误，我假设已写入stderr：
错误：dbus.proxies：内省错误：1.4：/org/freedesktop/Thermald：dbus.exceptions.DBusException：org.freedesktop.DBus.Error.AccessDenied：拒绝发送消息，2个匹配的规则； type =“method_call”，sender =“：1.974”（uid = 1000 pid = 20020 comm =“/usr/bin/python ./mmm”）interface =“org.freedesktop.DBus.Introspectable”成员=“Introspect”错误name =“（未设置）”requested_reply =“0”目的地=“：1.4”（uid = 0 pid = 1309 comm =“/ usr / sbin / Thermald --no-daemon --dbus-enable”）
抱歉用非正统的“引用”而不是code块。我想节省向右滚动 8 英里的时间。
我可以用以下方法捕获错误：
except dbus.exceptions.DBusException as err:
# Same as dbus.DBusException
print('\ndbus.exceptions.DBusException:', service)
print(err.message+'\n')
return False
except dbus.DBusException as err:
# Same as dbus.exceptions.DBusException
print('\ndbus.DBusException:', service)
print(err.message+'\n')
return False
然而它只是生成我的 except 这是最多之前的错误消息。但它并没有抑制通常发生的先前错误消息？？？
dbus.exceptions.DBusException: org.freedesktop.thermald
Rejected send message, 2 matched rules; type="method_call", sender=":1.974" (uid=1000 pid=20020 comm="/usr/bin/python ./mmm ") interface="org.freedesktop.DBus.Introspectable" member="Introspect" error name="(unset)" requested_reply="0" destination=":1.4" (uid=0 pid=1309 comm="/usr/sbin/thermald --no-daemon --dbus-enable ")
我总共收到 4 个系统服务 DBus“访问被拒绝”错误，缩写如下：
ERROR:dbus.proxies:Introspect error on :1.19:/fi/epitest/hostap/WPASupplicant:
ERROR:dbus.proxies:Introspect error on :1.19:/fi/w1/wpa_supplicant1:
ERROR:dbus.proxies:Introspect error on :1.20:/org/freedesktop/NetworkManager/dnsmasq:
ERROR:dbus.proxies:Introspect error on :1.4:/org/freedesktop/thermald:
这些似乎都是常见的 Ubuntu 错误（我使用的是 16.04.6 LTS，内核 4.14.170，Gnome 3.18）。我不想修复这些错误。对于我的项目，我不需要检查这些 DBus 服务。我只是想抑制错误消息。
FWIW 我还收到两个会话服务 DBUS 错误能成功捕获：
============== Session services ================
Object path: '/org/freedesktop/network-manager-applet' contains invalid character '-'
Object path: '/org/nautilus-actions/DBus' contains invalid character '-'
我认为由此邮政他们可能必须被转义，例如\-。这些错误的真正含义以及如何修复它们也很好。
FWIW 再次是我的代码：
def refresh_listdata(self, listdata):
import json
# If we delete list and append nothing appears (garbage collecctor).
# listdata = []
listdata *= 0 # https://stackoverflow.com/a/44349418/6929343
bus = dbus.SystemBus()
print ('\n============= System services =================\n')
for service in dbus.SystemBus().list_names():
# Skip over ":1.20", ":1.65", etc.
if not service.startswith(":") :
# print(service)
object_path=service.replace(".", "/")
object_path = "/" + object_path
dictionary = self.rec_intro(bus, service, object_path)
# print(dictionary)
if dictionary != False :
listdata.append(dictionary)
bus = dbus.SessionBus()
print ('\n============== Session services ================\n')
for service in dbus.SessionBus().list_names():
if not service.startswith(":") :
# print(service)
object_path=service.replace(".", "/")
object_path = "/" + object_path
dictionary = self.rec_intro(bus, service, object_path)
# print(dictionary)
if dictionary != False :
listdata.append(dictionary)
# print ("\nlistdata[0]\n", listdata[0])
# print(json.dumps(listdata[0], indent=4, sort_keys=True))
def rec_intro(self, bus, service, object_path,
paths=None, serviceDict=None):
from xml.etree import ElementTree
#print(object_path)
if paths == None:
paths = {}
paths[object_path] = {}
if "-" in object_path :
print ("Object path: '" + object_path + \
"' contains invalid character '-'")
return False
try:
obj = bus.get_object(service, object_path)
except:
print('Cannot get object: ', service, object_path)
return False
try:
iface = dbus.Interface(obj, 'org.freedesktop.DBus.Introspectable')
except:
print('Interface error:', obj)
return False
try:
xml_string = iface.Introspect()
# except DBusException as err:
# # NOT DEFINED!
# print('\nDBusException:', service)
# print(err.message+'\n')
# return False
except dbus.proxies as err:
print('\ndbus.proxies:Introspect error:', service)
print(err.message+'\n')
return False
# except org.freedesktop.DBus.Error.AccessDenied as err:
# # NOT DEFINED!
# print('\norg.freedesktop.DBus.Error.AccessDenied:', service)
# print(err.message)
# return False
except dbus.exceptions.DBusException as err:
# Same as dbus.DBusException
print('\ndbus.exceptions.DBusException:', service)
print(err.message+'\n')
return False
except dbus.DBusException as err:
# Same as dbus.exceptions.DBusException
print('\ndbus.DBusException:', service)
print(err.message+'\n')
return False
except:
print('No permissions to:', bus, service, object_path)
return False
for child in ElementTree.fromstring(xml_string):
if child.tag == 'node':
if object_path == '/':
object_path = ''
new_path = '/'.join((object_path,
child.attrib['name']))
self.rec_intro(bus, service, new_path)
else:
if object_path == "":
object_path = "/"
functiondict = {}
paths[object_path][child.attrib["name"]] = functiondict
for func in child.getchildren():
if func.tag not in functiondict.keys():
functiondict[func.tag] = []
functiondict[func.tag].append(func.attrib["name"])
if serviceDict == None:
serviceDict = {}
serviceDict[service] = paths
return serviceDict
答案1
事实证明，由于 dbus over systemd 的“设计缺陷”，我并不是第一个遇到此问题的人。解决方案是这样的：
def BuildNoPermissions(self, bus):
''' Errors add 5 seconds:
ERROR:dbus.proxies:Introspect error on :1.4:/org/freedesktop/thermald:
dbus.exceptions.DBusException: org.freedesktop.DBus.Error.AccessDenied:
Trap this error by first:
Build list of objects with no introspection.
Add to list if entry:
<policy context="default">
<deny own="fi.epitest.hostap.WPASupplicant"/>
<deny own="fi.w1.wpa_supplicant1"/>
</policy>
...exists. Add each deny entry to list to trap error:
ERROR:dbus.proxies:Introspect error on :1.19:/fi/w1/wpa_supplicant1 ...
Then before introspecting dbus make sure item isn't on list. If it is
on list then create necessary "No permissions" entry instead.
Now all that is left is:
ERROR:dbus.proxies:Introspect error on :1.1450:/org/freedesktop/
NetworkManager/dnsmasq:
Found in:
/etc/dbus-1/system.d/org.freedesktop.NetworkManager.conf:
<deny own="org.freedesktop.NetworkManager.dnsmasq"/>
Problem is NetworkManager has Introspect but denies dnsmasq so check
deny for all *.conf files even ones with introspect.
NOTE: when running with sudo things get worse:
ERROR:dbus.proxies:Introspect error on :1.19:/fi/epitest/hostap/
WPASupplicant/Interfaces/62: dbus.exceptions.DBusException:
org.freedesktop.DBus.Error.NoReply: Message recipient disconnected
from message bus without replying
... and then Ubuntu prints system crash message with option to report.
'''
# print ('\n============= BuildNoPermissions =================\n')
# print (bus, '\n')
result = os.popen("grep -Li introspect /etc/dbus-1/system.d/*"). \
read().splitlines()
for line in result:
base=os.path.basename(line) # remove path prefix
base=os.path.splitext(base)[0] # remove extension suffix
''' Must open up file to see if <deny> is used and add them
'''
# print (base)
self.NoPermissions.append(base)
result = os.popen("grep 'deny own' /etc/dbus-1/system.d/*"). \
read().splitlines()
for deny in result:
# [1::2] is a slicing which extracts odd values
d = deny.split('"')[1::2]
self.NoPermissions.append(d[0])
# Only 1 per line, so take index 0
# print (d[0])
对所有评论感到抱歉，但最好将它们保留在原处，而不是删除它们（或更糟糕的是重写它们）。
为了调用例程，修改了原始函数：
bus = dbus.SystemBus()
self.BuildNoPermissions(bus)
# print ('\n============= System services =================\n')
# print (self.NoPermissions, '\n')
for service in bus.list_names():
# Skip over ":1.20", ":1.65", etc.
if not service.startswith(":") :
denied = False
for deny in self.NoPermissions:
if deny == service:
denied = True
break
if denied: continue
# print(service)
object_path=service.replace(".", "/")
object_path = "/" + object_path
dictionary = self.rec_intro(bus, service, object_path)
# print(dictionary)
if dictionary != False :
listdata.append(dictionary)
额外的答案...去掉-对象路径名称：
if "-" in object_path :
# Bug: https://bugs.launchpad.net/snappy/+bug/1449722
object_path = object_path.replace("-", "")