I. Introduction
The Proc file system provides users with the current state of the system in the form of a file system, and dynamically reads the required information from the same kernel, which only exists in the memory and does not occupy external memory space.
2. Experimental content
Question A:
1. cpu type
2, kernel version
Question B:
1. The time since the system was started, reported as dd:hh:mm:ss
Question C:
1. How long does it take for the CPU to execute user mode, system mode, and idle state
? 2. How many disk requests
? 3. How many context switches?
4. How many processes are started
Question D:
1. Total memory
2. Available memory
3. System load average
3. Experimental code
/*****************************************
*
* Proc 文件系统
*
* Copyright: (C) 2018.3.31 by shaomingshan
*
* Compile: gcc -o main main.c
*
* Execute: ./main -a
*
*****************************************/
#include <stdio.h>
#include <sys/time.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#define LB_SIZE 80
enum TYPE{STANDARD,SHORT,LONG};
FILE *thisProcFile; //Proc 打开文件指针
struct timeval now; //系统时间日期
enum TYPE reportType; //观察报告类型
char repTypeName[16];
char *lineBuf; //proc 文件读出行缓冲
int interval; //系统负荷监测时间间隔
int duration; //系统负荷监测时段
int iteration;
char c1,c2; //字符处理单元
void sampleLoadAvg() { //观察系统负荷
int i=0;
//打开负荷文件
if ((thisProcFile = fopen("/proc/loadavg", "r")) == NULL)
{
printf("Open Failed\n");
return;
}
//读出、处理读出行，如去除前导空格和无用空格
fgets(lineBuf, LB_SIZE+1, thisProcFile);
char * c3 = strtok(lineBuf, " ");
//将读出行分出不同字段,按照字段的不同含义处理为可阅读格式
//打印处理好的信息内容
while (c3 != NULL) {
i ++;
switch (i) {
case 1:
printf("1分钟内平均负载: ");
break;
case 2:
printf("5分钟内平均负载: ");
break;
case 3:
printf("15分钟内平均负载: ");
break;
case 4:
printf("活动进程比: ");
break;
case 5:
printf("最近进程号: ");
break;
}
printf("%s\n", c3);
c3 = strtok(NULL, " ");
}
fclose(thisProcFile);
}
void sampleTime() {//观察系统启动时间
long uptime,idletime;
int day,hour,minute,second;
int i,j;
char temp[80];
i=j=0;
//打开计时文件
//读出、处理读出行，如去除前导空格和无用空格
thisProcFile = fopen("/proc/uptime", "r");
fgets(lineBuf, LB_SIZE+1, thisProcFile);
//将读出行分出不同字段,按照字段的不同含义处理为可阅读格式
//将启动时间的秒数转换为长整数
uptime = atol(strtok(lineBuf, " "));
//转换成日时钟秒
day = uptime/3600/24;
hour = uptime/3600%24;
minute = uptime/60%60;
second = uptime%60;
//打印处理好的信息内容
printf("uptime: %2ldd:%2ldh:%2ldm:%2lds\n",
day, hour, minute, second);
//将启动时间的空闲秒数转换为长整数
idletime = atol(strtok(NULL, " "));
//转换成日时钟秒
day = idletime/3600/24;
hour = idletime/3600%24;
minute = idletime/60%60;
second = idletime%60;
//打印处理好的信息内容
printf("idletime: %2ldd:%2ldh:%2ldm:%2lds\n",
day, hour, minute, second);
}
int main(int argc,char *argv[])
{
lineBuf = (char *)malloc(LB_SIZE+1);
reportType = STANDARD;
strcpy(repTypeName,"Standard");
if(argc >1){
sscanf(argv[1],"%c%c",&c1,&c2);//取命令行选择符
if(c1!='-'){ //提示本程序命令参数的用法
exit(1);
}
if(c2 == 'a'){
//观察部分 A
printf("**********PART A **********\n");
reportType = SHORT;
strcpy(repTypeName,"Short");
//取出并显示系统当前时间
//读出并显示机器名
//读出并显示全部 CPU 信息
//读出并显示系统版本信息
thisProcFile = fopen("/proc/cpuinfo", "r");
while (!feof(thisProcFile)) {
fgets(lineBuf, LB_SIZE+1, thisProcFile);
if (strstr(lineBuf, "model name")) {
printf("%s", lineBuf);
break;
}
}
fclose(thisProcFile);
system("uname -r");
}
else if(c2 == 'b'){
//观察部分 B
printf("**********PART B **********\n");
//打开内存信息文件
//读出文件全部的内容
//处理并用方便阅读的格式显示
//观察系统启动时间
sampleTime();
}
else if(c2 == 'c'){
//观察部分 C
printf("**********PART C**********\n");
//打开系统状态信息文件
thisProcFile = fopen("/proc/stat", "r");
//读出文件全部的内容
//处理并用方便阅读的格式显示
fgets(lineBuf, LB_SIZE+1, thisProcFile);
while (!feof(thisProcFile)) {
char *output = strtok(lineBuf, " ");
if (!strcmp(output, "cpu")) {
int i = 0;
while (i < 4) {
output = strtok(NULL, " ");
switch (i) {
case 0:
printf("用户态时间: %s\n", output);
break;
case 1:
break;
case 2:
printf("系统态时间: %s\n", output);
break;
case 3:
printf("空闲态时间: %s\n", output);
break;
}
i++;
}
} else if (!strcmp(output, "intr")) {
output = strtok(NULL, " ");
printf("磁盘请求: %s\n", output);
} else if (!strcmp(output, "ctxt")) {
output = strtok(NULL, " ");
printf("上下文切换: %s\n", output);
} else if (!strcmp(output, "processes")) {
output = strtok(NULL, " ");
printf("启动进程数: %s\n", output);
}
fgets(lineBuf, LB_SIZE+1, thisProcFile);
}
fclose(thisProcFile);
}
else if(c2 == 'd'){
//观察部分 D
printf("**********PART D **********\n");
if(argc<4){
printf("usage:observer [-b] [-c][-d int dur]\n");
exit(1);
}
thisProcFile = fopen("/proc/meminfo", "r");
int i = 0;
// 内存信息文件
while (i++ < 3) {
fgets(lineBuf, LB_SIZE+1, thisProcFile);
strtok(lineBuf, " ");
char *output = strtok(NULL, " ");
switch (i) {
case 1:
printf("总内存: ");
break;
case 2:
printf("空闲内存：");
break;
case 3:
printf("可用内存：");
}
printf("%s\n", output);
}
fclose(thisProcFile);
reportType = LONG;
strcpy(repTypeName,"Long");
//用命令行参数指定的时间段和时间间隔连续的
interval = atol(argv[2]);
duration = atol(argv[3]);
//读出系统负荷文件的内容用方便阅读的格式显示
for (int i = 0; i < duration / interval; ++i) {
sampleLoadAvg();
// 系统负荷信息
sleep(interval);
}
}
}
}
4. Operation results
Please correct me if there is any mistake