系统监控技术 -- 主机监控，信息转发，前台显示

1. 模块关系图

2. 定时器模块 == 模拟定时器 + 基本定时器

模拟定时器结构

typedef struct stuSimTimer
{
    char szName[20];	//定时器时间
    int  nInterval;		//定时间隔，取0时表示取消定时
    time_t nLast;		//上次定时的系统时间
    int  nRemain;		//剩余时间
    int (*pfunc)(char *);	//定时到达 执行代码
} SIMTIMER;
typedef SIMTIMER * PSIMTIMER;

模拟定时器有两种方法：

a: 相对时间法

for (i=0; i<nTopTimer; i++)
    {
        sTimer[i].nRemain--;
        if (sTimer[i].nRemain <= 0)
        {
            sTimer[i].pfunc(sTimer[i].szName);
            sTimer[i].nRemain = sTimer[i].nInterval;
        }
    }

b: 绝对时间法

for (i=0; i<nTopTimer; i++)
        {
            if(time(NULL) - sTimer[i].nLast >= sTimer[i].nInterval)
            {
                sTimer[i].pfunc(sTimer[i].szName);
                sTimer[i]. nLast = time(NULL);
            }
        }

基本定时器也有两种方法：

a: 循环定时

while(1)
{
    sleep(1);
    ........
}

b:信号定时

void timefunc(int sig)
{
    .....
    signal(SIGALRM, timefunc);
    alarm(n);
}
.......

定时器示例一：循环定时 + 绝对时间

#include<time.h>
#include<iostream>
using namespace std;

typedef struct stuSimTimer
{
    char szName[20];
    int  nInterval;
    time_t nLast;
    int  nRemain;
    int (*pfunc)(char *);
} SIMTIMER;
typedef SIMTIMER * PSIMTIMER;

int func1(char *p)
{
    cout << time(NULL) <<"Now Timer is: " << p << endl;
    //PrintLog(stdout, "Now Timer : %s", p);
    return 0;
}

#define MAXTIMER 20
SIMTIMER sTimer[MAXTIMER] =
{
    {"TIMER1", 10, 0, 10, func1},
    {"TIMER2", 4, 0, 4, func1}
};
int nTopTimer = 2;

int main()
{
    int i;
    while(1)
    {
        sleep(1);

        for (i=0; i<nTopTimer; i++)
        {
            if(time(NULL) - sTimer[i].nLast >= sTimer[i].nInterval)
            {
                sTimer[i].pfunc(sTimer[i].szName);
                sTimer[i]. nLast = time(NULL);
            }
        }
    }
}

定时器示例二：信号定时 + 相对时间

#include<stdio.h>
#include<time.h>
#include<iostream>
#include<signal.h>
using namespace std;

typedef struct stuSimTimer
{
    char szName[20];
    int  nInterval;
    time_t nLast;
    int  nRemain;
    int (*pfunc)(char *);
} SIMTIMER;
typedef SIMTIMER * PSIMTIMER;

int func1(char *p)
{
    //PrintLog(stdout, "Now Timer : %s", p);
    cout << time(NULL) <<"Now Timer is: " << p << endl;
    return 0;
}

#define MAXTIMER 20
SIMTIMER sTimer[MAXTIMER] =
{
    {"TIME1", 10, 0, 10, func1},
    {"TIMER2", 4, 0, 4, func1}
};
int nTopTimer = 2;

void timefunc(int sig)
{
    int i;

    for (i=0; i<nTopTimer; i++)
    {
        sTimer[i].nRemain--;
        if (sTimer[i].nRemain <= 0)
        {
            sTimer[i].pfunc(sTimer[i].szName);
            sTimer[i].nRemain = sTimer[i].nInterval;
        }
    }
    signal(SIGALRM, timefunc);
    alarm(1);
}

int main()
{
    signal(SIGALRM, timefunc);
    alarm(1);
    cout << "----- Begin -------" << endl;
    //PrintLog(stdout, "---Begin---");
    while(1)
    {
        sleep(100);
    }
}

3. 监控代码示例，消息队列，进程监控，文件系统监控。。。

#include <iostream>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/types.h>
#include <sys/msg.h>
#include <sys/vfs.h>
using namespace std;

int GetMsg1(char *pHost) //监控有没有0x1234这个消息队列
{
    char szBuf[256], szFmt[] = "%s|MSG|0x1234|%d|%d|%d|%s
";
    struct msqid_ds buf;
    int msgid, unused;
    float rate;
    memset(&buf, 0, sizeof(buf));

    if ((msgid = msgget(0x1234, 0666)) == -1 ||
        msgctl(msgid, IPC_STAT, &buf) == -1)
    {
        printf(szFmt, pHost, 0, 0, 1, strerror(errno));
        return 0;
    }
    unused = buf.msg_qbytes - buf.msg_cbytes;
    rate = (unused*1.0) / buf.msg_qbytes;
    memset(szBuf, 0, sizeof(szBuf));
    sprintf(szBuf, "space: %d of %d available (%.2f%%).", unused, buf.msg_qbytes, rate*100);
    if (rate >= 0.9)
    {
        printf(szFmt, pHost, unused , buf.msg_qbytes, 2, szBuf);
    }
    else
    {
        printf(szFmt, pHost, unused , buf.msg_qbytes, 0, szBuf);
    }
}

int GetProcess1(char *pHost)  //监控有没有monitor_type这个进程
{
    int all = 0, off;
    char szLine[256], szFmt[] = "%s|PROC|%s|%d|1|%d|%s
";
    char *ProcessName = "monitor_type";
    char *ShellName = "ps -ef|grep monitor_type";
    FILE *pfile;
    char szUID[20], szPID[20], szPPID[20], szC[20], szSTIME[20], szTTY[20], szTIME[200], szCMD[255];
    if ((pfile = popen(ShellName, "r")) == NULL)
    {
        printf(szFmt, ProcessName, pHost, 0, 1, "error:shell");
    }
    else
    {
        memset(szLine, 0, sizeof(szLine));
        while (fgets(szLine, sizeof(szLine), pfile) != NULL)
        {
            sscanf(szLine, "%s%s%s%s%s%s%s%s", szUID, szPID, szPPID, szC, szSTIME, szTTY, szTIME,szCMD);
            //cout << "szLine: " << szLine << endl;
            //cout << "szCMD: " << szCMD << endl;
            if (strlen(szCMD) >= strlen(ProcessName))
            {
                off = strlen(szCMD)-strlen(ProcessName);
                if (strcmp(szCMD+off, ProcessName) == 0) all++;
            }
        }
        pclose(pfile);
        if (all > 0) printf(szFmt, pHost, ProcessName, all, 0, "OK");
        else printf(szFmt, pHost, ProcessName, all, 1, "No Process");
    }
}

int GetFilesysValue(char *pHost, char *pPath)  //监控制定目录文件系统的信息
{
    char szFmt[] = "%s|FILE|%s|%d|%d|%d|%s
", szRate1[30], szRate2[30];
    struct statfs buf;
    float rused, rinode;
    int nalarm;
    if (statfs(pPath, &buf) == 0)
    {
        rused = (double)buf.f_bfree / buf.f_blocks;
        rinode = (double)buf.f_ffree / buf.f_files;
        sprintf(szRate1, "block : %.2f%% available", rused*100);
        sprintf(szRate2, "inode : %.2f%% available", rinode*100);
        if (rused >= 0.15) nalarm = 0;
        else if (rused >= 0.5) nalarm = 2;
        else nalarm = 1;
        printf(szFmt, pHost, pPath, buf.f_bfree, buf.f_blocks, nalarm, szRate1);
        if (rinode >= 0.15) nalarm = 0;
        else if (rinode >= 0.5) nalarm = 2;
        else nalarm = 1;
        printf(szFmt, pHost, pPath, buf.f_ffree, buf.f_files, nalarm, szRate2);
    }
    return 0;
}

int main()
{    
    cout << "test monitor type ----> msg " << endl;
    int msgid = msgget(0x1234, 0666 | IPC_CREAT);
    msgsnd(msgid, "1", strlen("1"), 0);
    GetMsg1("kevin_pc");

    cout << "test monitor type ----> process " << endl;
    GetProcess1("kevin_pc");

    cout << "test monitor type ----> filesystem " << endl;
    GetFilesysValue("kevin_pc", "/usr");
    GetFilesysValue("kevin_pc", "/");

    return 0;
}