通过网络连接模拟处理器QEMU的monitor

QEMU是一套开源的模拟处理器,在GNU/Linux平台上使用广泛,本文我们将通过网络连接QEMU的监控器monitor.

1.QEMU monitor支持远程telnet访问:

[root@kvm-host ~]# qemu-system-x86_64 -enable-kvm -smp 2 -m 1024 vm2.img -monitor telnet:10.1.77.82:4444,server,nowait

关于这里-monitor的选项,做如下说明:

1. tcp–rawtcpsockets#下面第2点，我的举例是RAWTCPsocket
2. telnet–thetelnetprotocolisusedinsteadofrawtcpsockets.ThisisthepreferredoptionovertcpasyoucanbreakoutofthemonitorusingCtrl-]thentypingquit.Youcan’tbreakoutofthemonitorlikethisafterconnectingwiththerawsocketoption
3. 10.1.77.82–Listenonthishost/IPonly.Youcanuse127.0.0.1ifyouwanttoonlyallowconnectionslocally.Ifyouwanttolistenonanyipaddressontheserver,justleavethisblanksoyouendupwithtwoconsecutivecolonsie“::”.
4. 4444–portnumbertolistenon.
5. server–listeninginservermode
6. nowait–qemuwillwaitforaclientsocketapplicationtoconnecttotheportbeforecontinuingunlessthisoptionisused.Inmostcasesyou’llwanttousethenowaitoption.

通过telnet连接到远程的QEMU monitor上,代码如下:

1. jay@jay-linux:~$telnet10.1.77.824444
2. Trying10.1.77.82...
3. Connectedto10.1.77.82.
4. Escapecharacteris'^]'.
5. QEMU1.7.50monitor-type'help'formoreinformation
6. (qemu)infokvm
7. kvmsupport:enabled
8. (qemu)infostatus
9. VMstatus:running
10. (qemu)helpmigrate
11. migrate[-d][-b][-i]uri--migratetoURI(using-dtonotwaitforcompletion)
12. -bformigrationwithoutsharedstoragewithfullcopyofdisk--phpfensi.com
13. -iformigrationwithoutsharedstoragewithincrementalcopyofdisk(baseimagesharedbetweensrcanddestination)
14. (qemu)ctrl+]（断掉telnet连接）
15. telnet>quit（退出telnet）
16. Connectionclosed.

2.QEMU monitor支持RAW socket的远程访问,代码如下:

[root@kvm-host ~]# qemu-system-x86_64 -enable-kvm -smp 2 -m 1024 vm2.img -monitor tcp:10.1.77.82:4444,server,nowait

可以使用netcat去连接这个socket,代码如下:

1. jay@jay-linux:~$nc10.1.77.824444
2. QEMU1.7.50monitor-type'help'formoreinformation
3. (qemu)infokvm
4. infokvm
5. kvmsupport:enabled
6. (qemu)^C

自己写了个socket程序示例如连接monitor,效果如下:

1. jay@jay-linux:~/workspace/c-cpp.git/c2013$./monitor_client
2. sendingcommand'infokvm
3. 'toremoteqemumonitor
4. outputfromqemumonitor:QEMU1.7.50monitor-type'help'formoreinformation
5. ??,?
6. outputfromqemumonitor:(qemu)infokvm
7. kvmsupport:enabled
8. (qemu)

上面那个连接monitor的socket程序示例为:

https://github.com/smilejay/c-cpp/blob/master/c2013/socket_qemu_monitor_client.c

代码如下:

1. /*socket_qemu_monitor_clinet.c
2. *ConnecttoremoteQEMUmonitorsocketandsendingacommandtothemonitor.
3. *author:Jay<smile665@gmail.com>
4. */
6. #include<sys/types.h>
7. #include<sys/socket.h>
8. #include<stdio.h>
9. #include<netinet/in.h>
10. #include<arpa/inet.h>
11. #include<unistd.h>
12. #include<stdlib.h>
13. #include<string.h>
15. intmain(intargc,char*argv[])
16. {
17. intsockfd;
18. intlen;
19. structsockaddr_inaddress;
20. intresult;
21. char*cmd="infokvmn";
22. charoutput[200];
24. /*Createasocketfortheclient.*/
25. sockfd=socket(AF_INET,SOCK_STREAM,0);
27. /*Namethesocket,asagreedwiththeserver.*/
28. address.sin_family=AF_INET;
29. address.sin_addr.s_addr=inet_addr("10.1.77.82");
30. address.sin_port=htons(4444);
31. len=sizeof(address);
33. /*Nowconnectoursockettotheserver'ssocket.*/
34. result=connect(sockfd,(structsockaddr*)&address,len);
36. if(result==-1){
37. perror("oops:socketconnetionfailed.");
38. exit(1);//phpfensi.com
39. }
41. /*Wecannowread/writeviasockfd.*/
42. printf("sendingcommand'%s'toremoteqemumonitorn",cmd);
43. write(sockfd,cmd,strlen(cmd));
44. read(sockfd,output,sizeof(output));
45. printf("outputfromqemumonitor:%sn",output);
46. read(sockfd,output,sizeof(output));
47. printf("outputfromqemumonitor:%sn",output);
48. close(sockfd);
49. exit(0);
50. }