Linux C++ 获取某一进程的CPU占用率以及内存占用情况

#include <stdio.h>
#include <unistd.h>
#include <sys/time.h>
#include <string.h>
#include <stdlib.h>

#define VMRSS_LINE 17
#define VMSIZE_LINE 13
#define PROCESS_ITEM 14

typedef struct {
unsigned long user;
unsigned long nice;
unsigned long system;
unsigned long idle;
}Total_Cpu_Occupy_t;

typedef struct {
unsigned int pid;
unsigned long utime;  //user time
unsigned long stime;  //kernel time
unsigned long cutime; //all user time
unsigned long cstime; //all dead time
}Proc_Cpu_Occupy_t;

//获取第N项开始的指针
const char* get_items(const char*buffer ,unsigned int item){

const char *p =buffer;

int len = strlen(buffer);
int count = 0;

for (int i=0; i<len;i++){
if (' ' == *p){
count ++;
if(count == item -1){
p++;
break;
}
}
p++;
}

return p;
}

//获取总的CPU时间
unsigned long get_cpu_total_occupy(){

FILE *fd;
char buff[1024]={0};
Total_Cpu_Occupy_t t;

fd =fopen("/proc/stat","r");
if (nullptr == fd){
return 0;
}

fgets(buff,sizeof(buff),fd);
char name[64]={0};
sscanf(buff,"%s %ld %ld %ld %ld",name,&t.user,&t.nice,&t.system,&t.idle);
fclose(fd);

return (t.user + t.nice + t.system + t.idle);
}

//获取进程的CPU时间
unsigned long get_cpu_proc_occupy(unsigned int pid){

char file_name[64]={0};
Proc_Cpu_Occupy_t t;
FILE *fd;
char line_buff[1024]={0};
sprintf(file_name,"/proc/%d/stat",pid);

fd = fopen(file_name,"r");
if(nullptr == fd){
return 0;
}

fgets(line_buff,sizeof(line_buff),fd);

sscanf(line_buff,"%u",&t.pid);
const char *q =get_items(line_buff,PROCESS_ITEM);
sscanf(q,"%ld %ld %ld %ld",&t.utime,&t.stime,&t.cutime,&t.cstime);
fclose(fd);

return (t.utime + t.stime + t.cutime + t.cstime);
}

//获取CPU占用率
float get_proc_cpu(unsigned int pid){

unsigned long totalcputime1,totalcputime2;
unsigned long procputime1,procputime2;

totalcputime1=get_cpu_total_occupy();
procputime1=get_cpu_proc_occupy(pid);

usleep(200000);

totalcputime2=get_cpu_total_occupy();
procputime2=get_cpu_proc_occupy(pid);

float pcpu = 0.0;
if(0 != totalcputime2-totalcputime1){
pcpu=100.0 * (procputime2-procputime1)/(totalcputime2-totalcputime1);
}

return pcpu;
}

//获取进程占用内存
unsigned int get_proc_mem(unsigned int pid){

char file_name[64]={0};
FILE *fd;
char line_buff[512]={0};
sprintf(file_name,"/proc/%d/status",pid);

fd =fopen(file_name,"r");
if(nullptr == fd){
return 0;
}

char name[64];
int vmrss;
for (int i=0; i<VMRSS_LINE-1;i++){
fgets(line_buff,sizeof(line_buff),fd);
}

fgets(line_buff,sizeof(line_buff),fd);
sscanf(line_buff,"%s %d",name,&vmrss);
fclose(fd);

return vmrss;
}

//获取进程占用虚拟内存
unsigned int get_proc_virtualmem(unsigned int pid){

char file_name[64]={0};
FILE *fd;
char line_buff[512]={0};
sprintf(file_name,"/proc/%d/status",pid);

fd =fopen(file_name,"r");
if(nullptr == fd){
return 0;
}

char name[64];
int vmsize;
for (int i=0; i<VMSIZE_LINE-1;i++){
fgets(line_buff,sizeof(line_buff),fd);
}

fgets(line_buff,sizeof(line_buff),fd);
sscanf(line_buff,"%s %d",name,&vmsize);
fclose(fd);

return vmsize;
}

//进程本身
int get_pid(const char* process_name, const char* user = nullptr)
{
if(user == nullptr){
user = getlogin();
}

char cmd[512];
if (user){
sprintf(cmd, "pgrep %s -u %s", process_name, user);
}

FILE *pstr = popen(cmd,"r");

if(pstr == nullptr){
return 0;
}

char buff[512];
::memset(buff, 0, sizeof(buff));
if(NULL == fgets(buff, 512, pstr)){
return 0;
}

return atoi(buff);
}

int main(int argc, char *argv[])
{

if(argc < 2){
printf("Usage:test <process_name> [user]\n");
return 1;
}

unsigned int pid=0;

if(argc > 2){
pid = get_pid(argv[1],argv[2]);
}
else{
pid = get_pid(argv[1]);
}

printf("pid=%d\n",pid);
printf("pcpu=%f\n",get_proc_cpu(pid));
printf("procmem=%d\n",get_proc_mem(pid));
printf("virtualmem=%d\n",get_proc_virtualmem(pid));
return 0;
}