Linux 下监控程序 -- 共享内存通讯，消息订阅发布

实习的时候写的小练习程序：

VMSTAT.h

此代码用以从服务器获取运行状态信息

class VMSTAT{
public:
double stat[20];
/*
*       Proc
*
* 0:r: The number of processes waiting for run time.
* 1:b: The number of processes in uninterruptible sleep.
*
*       Memory
*
* 2:swpd: the amount of virtual memory used.
* 3:free: the amount of idle memory.
* 4:buff: the amount of memory used as buffers.
* 5:cache: the amount of memory used as cache.
*
*       Swap
*
* 6:si: Amount of memory swapped in from disk (/s).
* 7:Amount of memory swapped to disk (/s).
*
*       IO
*
* 8:bi: Blocks received from a block device (blocks/s).
* 9:bo: Blocks sent to a block device (blocks/s).
*
*       System
*
* 10:in: The number of interrupts per second, including the clock.
* 11:cs: The number of context switches per second.
*
*       CPU
*
* 12:us: Time spent running non-kernel code. (user time, including nice time)
* 13:sy: Time spent running kernel code. (system time)
* 14:id: Time spent idle. Prior to Linux 2.5.41, this includes IO-wait time.
* 15:wa: Time spent waiting for IO. Prior to Linux 2.5.41, included in idle.
* 16:st: Time stolen from a virtual machine. Prior to Linux 2.6.11, unknown.
*
*       Add
*
* 17:Total Memory
* 18:Used Memory
* 19:CPU Usage
*/

void update()
{

//init array
FILE* file = popen("vmstat","r");
char buf[300];
fgets (buf , 300 , file);
fgets (buf , 300 , file);
fgets (buf , 300 , file);

int index=0;
for(int i = 0;i<300;i++)
{
while(buf[i]<'0'||buf[i]>'9') i++;
int tmp = 0;
while(buf[i]>='0'&&buf[i]<='9')
{
tmp = tmp*10 + (buf[i]-'0');
i++;
}
stat[index++] = tmp*1.0;
if(index == 17) break;
}
pclose(file);

//total memory
file = popen("cat /proc/meminfo","r");
double total=0;
fgets (buf , 300 , file);
char str[7];
for(int i=17;i<24;i++)
str[i-17]=buf[i];

for(int i=0;i<7;i++)
{
total =total*10+(str[i]==' '?0:(str[i]-'0'));
}

//calculate all
stat[17]=total;
stat[18]=total-stat[3];
stat[19]=100-stat[14];
pclose(file);

}

};

pshm.h

定义共享内存数据结构的结构体

定义主题ID

typedef struct tagMyStat
{
int attche_count;
int total;
int avaliable;
int used;
int cpu_useage;

} MyStat;

#define CENTOS_PER   (4499)  //主题CENTOS_PER 由服务器发布 客户端进行订阅 服务器可发布多个主题，而客户端可以选择其中若干个感兴趣的进行订阅

shmClient.cpp

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/shm.h>
#include  "VMSTAT.h"
#include "pshm.h"

int main()
{
void *shm = NULL;
MyStat *shared = NULL;

int shmid = shmget((key_t)CENTOS_PER,sizeof(MyStat),IPC_CREAT);
if(shmid == -1)
{
printf("%s\n","shmget failed!");
return 0;
}
shm = shmat(shmid, (void*)0, 0);
if(shm == (void*)-1)
{
printf("%s\n","shmat failed!");
}

printf("Memory attached at %lx\n", (long)shm);

shared = (MyStat*)shm;
shared->attche_count ++;

time_t rawtime;
struct tm * t;

while(1)
{
time ( &rawtime );
t = localtime ( &rawtime );

printf("Client@%d:%d:%d :Total: %d MB  Aviliable: %d MB  Used: %d MB  CPU: %d %\n",t->tm_hour,t->tm_min,t->tm_sec,shared->total,shared->avaliable,shared->used,shared->cpu_useage);
sleep(1);
}

shared->attche_count --;

if(shmdt(shm) == -1)
{
printf("%s\n","shmdt failed!");
}

if(shmctl(shmid, IPC_RMID, 0) == -1)
{
printf("%s\n","shmctl(IPC_RMID) failed!");
}

sleep(2);

return 0;
}

shmServer.cpp

#include <stdio.h>
#include <time.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/shm.h>
#include "VMSTAT.h"
#include "pshm.h"

int main()
{
void *shm = NULL;
MyStat *shared = NULL;

int shmid = shmget((key_t)CENTOS_PER,sizeof(MyStat),0666|IPC_CREAT);
if(shmid == -1)
{
printf("%s\n","shmget failed!");
return 0;
}
shm = shmat(shmid, (void*)0, 0);
if(shm == (void*)-1)
{
printf("%s\n","shmat failed!");
}

printf("Memory attached at %lx\n", (long)shm);

shared = (MyStat*)shm;
memset(shared, 0, sizeof(MyStat));
shared->attche_count=0;
VMSTAT s;

time_t rawtime;
struct tm * t;

while(1)
{
s.update();
shared->total = int(s.stat[17]/1000);
shared->avaliable = int(s.stat[3]/1000);
shared->used = int(s.stat[18]/1000);
shared->cpu_useage = int(s.stat[19]);

time ( &rawtime );
t = localtime ( &rawtime );

printf("Server@%2d:%2d:%2d (%d):Total: %d MB  Aviliable: %d MB  Used: %d MB  CPU: %d %\n",t->tm_hour,t->tm_min,t->tm_sec,shared->attche_count,shared->total,shared->avaliable,shared->used,shared->cpu_useage);
sleep(1);
}

if(shmdt(shm) == -1)
{
printf("%s\n","shmdt failed!");
}

if(shmctl(shmid, IPC_RMID, 0) == -1)
{
printf("%s\n","shmctl(IPC_RMID) failed!");
}

sleep(2);

return 0;
}

服务器运行截图：



客户端运行截图：