libvirt获取虚拟机的状态

最近需要获取虚拟机内CPU的利用率：尝试了多种方法，均不理想，以下是最后利用libvirt-devel开发包，实现一个功能函数。

示例如下：

<span style="font-size:18px;color:#009900;"><strong>#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <sys/time.h>
#include <libvirt/libvirt.h>
#include <libvirt/virterror.h>

#define NAME_SIZE 32
struct kvm_state{
char name[NAME_SIZE];
char rflags[16];// running  shutoff
int  mem;      //MB
int vcpus;
float  cpu_rate;     //
long long h_cpu_time;
struct timeval h_real_time;
};
void s_to_rflags(int state,char*buf){
switch(state){
case 1: // running
strcpy(buf,"running");
break;
case 2:  //blocked
strcpy(buf,"block");
break;
case 3: // paused
strcpy(buf,"paused");
break;
case 4: //shut down
strcpy(buf,"shut down");
break;
case 5:  // shut off
strcpy(buf,"shut off");
break;
case 6:  // crashed
strcpy(buf,"crashed");
break;
case 7: // suspended
strcpy(buf,"suspended");
break;
default: // none
strcpy(buf,"none");
break;
}
return ;
}

int GetAllDomainState(struct kvm_state*st){
virConnectPtr conn;
virDomainPtr *alldomain=NULL;
virDomainInfo domain_info;
int num=0,i=0;
struct timeval tv;
conn = virConnectOpen("qemu:///system");
if (conn == NULL) {
fprintf(stderr, "Failed to open connection to qemu+tcp://localhost/system\n");
return 0;
}
num=virConnectListAllDomains(conn,&alldomain,3);//
//st=(struct kvm_state*)malloc(sizeof(struct kvm_state)*num);
//memset(st,0,sizeof(struct kvm_state)*num);
for(i=0;i<num;i++){

strncpy(st[i].name,virDomainGetName(alldomain[i]),NAME_SIZE);   // name
//printf(":%s\n",virDomainGetXMLDesc(alldomain[i],1));
virDomainGetInfo(alldomain[i],&domain_info);
s_to_rflags(domain_info.state, st[i].rflags);// running state
st[i].mem=domain_info.memory/1024;//mem /mb
//domain_info.mexMem
st[i].vcpus=domain_info.nrVirtCpu;// vcpus
st[i].h_cpu_time=domain_info.cpuTime;
gettimeofday(&(st[i].h_real_time),NULL);
//virDomainFree(alldomain[i]);
}
sleep(1);
for(i=0;i<num;i++){
virDomainGetInfo(alldomain[i],&domain_info);
gettimeofday(&tv,NULL);
st[i].cpu_rate=((domain_info.cpuTime-st[i].h_cpu_time)/1000.0)/((tv.tv_sec-st[i].h_real_time.tv_sec)*1000000.0   + (tv.tv_usec- st[i].h_real_time.tv_usec));
st[i].cpu_rate=st[i].cpu_rate/st[i].vcpus*100.0;
virDomainFree(alldomain[i]);
}
virConnectClose(conn);
return num;
}
int main(){
int num;
struct kvm_state kvm[10];
num=GetAllDomainState(kvm);
}</strong></span>