为什么networkmanager.WatchState会引发恐慌？

huangapple
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英文:

Why networkmanager.WatchState panics?

问题

我需要在网络状态发生变化时监视网络变化，并在需要时设置一些路由规则（例如，如果接口重新启动，我需要重新设置IP路由表，因为源是动态的，无法硬编码）。为了实现这一点，我正在尝试使用networkmanager包，但WatchState出现了恐慌。有任何想法是为什么？

  1. package main
  3. import (
  4. 	"flag"
  5. 	"os"
  6. 	"launchpad.net/ubuntu-push/bus"
  7. 	"launchpad.net/ubuntu-push/bus/networkmanager"
  8. 	"launchpad.net/ubuntu-push/logger"
  9. )
  11. func main() {
  12. 	flag.Parse()
  14. 	lg := logger.NewSimpleLogger(os.Stderr, "info")
  15. 	endp := bus.SystemBus.Endpoint(networkmanager.BusAddress, lg)
  16. 	nm := networkmanager.New(endp, lg)
  17. 	watchState, cancel, err := nm.WatchState()
  18. 	if err != nil {
  19. 		log.Printf("error %v", err)
  20. 		return
  21. 	}
  22. 	defer cancel.Cancel()
  23. 	for state := range watchState {
  24. 		log.Printf("state is %v", state)
  25. 	}
  26. }

恐慌跟踪：

  1. panic: runtime error: invalid memory address or nil pointer dereference
  2. [signal 0xb code=0x1 addr=0x0 pc=0x488788]
  4. goroutine 1 [running]:
  5. launchpad.net/go-dbus/v1.(*ObjectProxy).WatchSignal(0x0, 0x616cd0, 0x1e, 0x5f0af0, 0xc, 0x7f9733d0e478, 0x0, 0x0)
  6. 	/root/go/src/launchpad.net/go-dbus/v1/dbus.go:97 +0x198
  7. launchpad.net/ubuntu-push/bus.(*endpoint).WatchSignal(0xc20803e0c0, 0x5f0af0, 0xc, 0xc20800a0e0, 0xc20802a530, 0x0, 0x0, 0x0, 0x0)
  8. 	/root/go/src/launchpad.net/ubuntu-push/bus/endpoint.go:133 +0x91
  9. launchpad.net/ubuntu-push/bus/networkmanager.(*networkManager).WatchState(0xc20800a0c0, 0x5bce80, 0x0, 0x0, 0x0, 0x0)
  10. 	/root/go/src/launchpad.net/ubuntu-push/bus/networkmanager/networkmanager.go:108 +0x1cf
  11. main.main()
  12. 	/root/go/src/github.com/vinkoo/net/main.go:16 +0x1f9
  14. goroutine 2 [runnable]:
  15. runtime.forcegchelper()
  16. 	/usr/local/go/src/runtime/proc.go:90
  17. runtime.goexit()
  18. 	/usr/local/go/src/runtime/asm_amd64.s:2232 +0x1
  20. goroutine 3 [runnable]:
  21. runtime.bgsweep()
  22. 	/usr/local/go/src/runtime/mgc0.go:82
  23. runtime.goexit()
  24. 	/usr/local/go/src/runtime/asm_amd64.s:2232 +0x1
  26. goroutine 4 [runnable]:
  27. runtime.runfinq()
  28. 	/usr/local/go/src/runtime/malloc.go:712
  29. runtime.goexit()
  30. 	/usr/local/go/src/runtime/asm_amd64.s:2232 +0x1
  31. exit status 2

编辑： 程序似乎在networkmanager的任何方法上都会出现恐慌。GetState的恐慌如下所示。

  1. goroutine 1 [running]:
  2. launchpad.net/go-dbus/v1.(*ObjectProxy).Call(0x0, 0x616c90, 0x1f, 0x5e26d0, 0x3, 0xc20801d5a0, 0x2, 0x2, 0x7f13a95d0b50, 0x0, ...)
  3. 	/root/go/src/launchpad.net/go-dbus/v1/dbus.go:77 +0x1d1
  4. launchpad.net/ubuntu-push/bus.(*endpoint).GetProperty(0xc20803e0c0, 0x5eac50, 0x5, 0x0, 0x0, 0x0, 0x0)
  5. 	/root/go/src/launchpad.net/ubuntu-push/bus/endpoint.go:169 +0x1cf
  6. launchpad.net/ubuntu-push/bus/networkmanager.(*networkManager).GetState(0xc20800a0c0, 0x5bce80)
  7. 	/root/go/src/launchpad.net/ubuntu-push/bus/networkmanager/networkmanager.go:79 +0x62
  8. main.main()
英文:

I need to watch network changes and set some routing rules whenever the network status changes(e.g. if an interface is rebooted I need to set the ip routing tables again b/c the src is dynamic so I can't hardcode it).
To achieve this I'm trying to use networkmanager package but WatchState panics. Any idea why?

  1. package main
  3. import(
  4. 	"flag"
  5. 	"os" 
  6. 	"launchpad.net/ubuntu-push/bus"
  7. 	"launchpad.net/ubuntu-push/bus/networkmanager"
  8. 	"launchpad.net/ubuntu-push/logger"
  10. )
  12. func main(){
  13. 	flag.Parse()
  14. 	
  15. 	lg := logger.NewSimpleLogger(os.Stderr, "info")
  16. 	endp := bus.SystemBus.Endpoint(networkmanager.BusAddress, lg)
  17. 	nm := networkmanager.New(endp, lg)
  18. 	watchState, cancel, err := nm.WatchState()
  19. 	if err !=nil{
  20. 		log.Printf("error %v", err)
  21. 		return
  22. 	}
  23. 	defer cancel.Cancel()
  24. 	for state := range watchState{
  25. 		log.Printf.("state is %v", state)
  26. 	}
  27. }

Panic trace

  1. panic: runtime error: invalid memory address or nil pointer dereference
  2. [signal 0xb code=0x1 addr=0x0 pc=0x488788]
  4.     goroutine 1 [running]:
  5.     launchpad.net/go-dbus/v1.(*ObjectProxy).WatchSignal(0x0, 0x616cd0, 0x1e, 0x5f0af0, 0xc, 0x7f9733d0e478, 0x0, 0x0)
  6.     	/root/go/src/launchpad.net/go-dbus/v1/dbus.go:97 +0x198
  7.     launchpad.net/ubuntu-push/bus.(*endpoint).WatchSignal(0xc20803e0c0, 0x5f0af0, 0xc, 0xc20800a0e0, 0xc20802a530, 0x0, 0x0, 0x0, 0x0)
  8.     	/root/go/src/launchpad.net/ubuntu-push/bus/endpoint.go:133 +0x91
  9.     launchpad.net/ubuntu-push/bus/networkmanager.(*networkManager).WatchState(0xc20800a0c0, 0x5bce80, 0x0, 0x0, 0x0, 0x0)
  10.     	/root/go/src/launchpad.net/ubuntu-push/bus/networkmanager/networkmanager.go:108 +0x1cf
  11.     main.main()
  12.     	/root/go/src/github.com/vinkoo/net/main.go:16 +0x1f9
  13.     
  14.     goroutine 2 [runnable]:
  15.     runtime.forcegchelper()
  16.     	/usr/local/go/src/runtime/proc.go:90
  17.     runtime.goexit()
  18.     	/usr/local/go/src/runtime/asm_amd64.s:2232 +0x1
  19.     
  20.     goroutine 3 [runnable]:
  21.     runtime.bgsweep()
  22.     	/usr/local/go/src/runtime/mgc0.go:82
  23.     runtime.goexit()
  24.     	/usr/local/go/src/runtime/asm_amd64.s:2232 +0x1
  25.     
  26.     goroutine 4 [runnable]:
  27.     runtime.runfinq()
  28.     	/usr/local/go/src/runtime/malloc.go:712
  29.     runtime.goexit()
  30.     	/usr/local/go/src/runtime/asm_amd64.s:2232 +0x1
  31.     exit status 2

Edit: It seems the program panics on any method from the networkmanager. GetState panics as follows.

  1. goroutine 1 [running]:
  2. launchpad.net/go-dbus/v1.(*ObjectProxy).Call(0x0, 0x616c90, 0x1f, 0x5e26d0, 0x3, 0xc20801d5a0, 0x2, 0x2, 0x7f13a95d0b50, 0x0, ...)
  3. 	/root/go/src/launchpad.net/go-dbus/v1/dbus.go:77 +0x1d1
  4. launchpad.net/ubuntu-push/bus.(*endpoint).GetProperty(0xc20803e0c0, 0x5eac50, 0x5, 0x0, 0x0, 0x0, 0x0)
  5. 	/root/go/src/launchpad.net/ubuntu-push/bus/endpoint.go:169 +0x1cf
  6. launchpad.net/ubuntu-push/bus/networkmanager.(*networkManager).GetState(0xc20800a0c0, 0x5bce80)
  7. 	/root/go/src/launchpad.net/ubuntu-push/bus/networkmanager/networkmanager.go:79 +0x62
  8. main.main()

答案1

得分: 0

我自己没有使用过这个包，但是从检查源代码（http://bazaar.launchpad.net/+branch/ubuntu-push/view/head:/bus/endpoint.go）来看，似乎你应该在调用endp.Dial之前调用networkmanager.New，否则endpoint.proxy将保持未初始化状态。

  1. endp := bus.SystemBus.Endpoint(networkmanager.BusAddress, lg)
  2. err := endp.Dial()
  3. if err != nil{
  4.     log.Printf("dial error %v", err)
  5.     return
  6. }
  7. defer endp.Close()
  8. nm := networkmanager.New(endp, lg)
英文:

I haven't used the package myself, but from inspecting the source code, it seems like you should call endp.Dial before networkmanager.New because otherwise, endpoint.proxy stays uninitialised.

  1. endp := bus.SystemBus.Endpoint(networkmanager.BusAddress, lg)
  2. err := endp.Dial()
  3. if err != nil{
  4.     log.Printf("dial error %v", err)
  5.     return
  6. }
  7. defer endp.Close()
  8. nm := networkmanager.New(endp, lg)

huangapple
  • 本文由 发表于 2015年7月3日 18:24:30
  • 转载请务必保留本文链接：https://go.coder-hub.com/31204482.html
  • dbus
  • go
  • network-programming
  • ubuntu
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