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>