〖Linux〗proc的一些文件读取操作

/*
* =====================================================================================
*
*       Filename:  proc_more.c
*
*    Description:
*
*        Version:  1.0
*        Created:  2013年08月07日 11时34分40秒
*       Revision:  none
*       Compiler:  gcc
*
*         Author:  linkscue (scue), linkscue@gmail.com
*   Organization:
*
* =====================================================================================
*/

#include <stdio.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
void sampleLoadAvg(){
int f=0;
char buffer[80]="";                         /* 定义字符串并初始化为'\0' */
char buf[5][10];
char *file="/proc/loadavg";
f = open(file, O_RDONLY);
if (f == 0)
{
printf("error to open: %s\n", file);
exit(EXIT_FAILURE);
}
read(f, (void *)buffer, 80);
sscanf(buffer, "%s %s %s %s %s",            /* sscanf()拆分成多个字符串 */
&buf[0],&buf[1],&buf[2],&buf[3],&buf[4]);
printf("一分钟平均负载：%s\n", buf[0]);
printf("五分钟平均负载：%s\n", buf[1]);
printf("一刻钟平均负载：%s\n", buf[2]);
printf("采样时刻的间隔：%s\n", buf[3]);
printf("最大线程的数目：%s\n", buf[4]);
close(f);
}
void sampleTime(){
int f=0;
char buffer[80]="";
char buf[2][10];
float seconds=0;
float secondr=0;
char *file="/proc/uptime";
f = open(file, O_RDONLY);
if (f == 0)
{
printf("error to open: %s\n", file);
exit(EXIT_FAILURE);
}
read(f, (void *)buffer, 80);
sscanf(buffer, "%s %s", &buf[0], &buf[1]);
close(f);
printf("系统运行时间：\t%s秒\n", buf[0]);
printf("系统空闲时间：\t%s秒\n", buf[1]);
close(f);
seconds=strtof(buf[0],NULL);
secondr=strtof(buf[1],NULL);
printf("系统运行时间：\t%03d天%02d时%02d分%02.6f秒\n",
(int)seconds/(24*3600),             /* 天 */
((int)seconds/(3600))%(24),         /* 时 */
((int)seconds/60)%60,               /* 分 */
((int)seconds%60)+(seconds-(int)seconds)); /* 秒(精确至毫秒) */
printf("系统空闲时间：\t%03d天%02d时%02d分%02.6f秒\n",
(int)secondr/(24*3600),             /* 天 */
((int)secondr/(3600))%(24),         /* 时 */
((int)secondr/60)%60,               /* 分 */
((int)secondr%60)+(secondr-(int)secondr)); /* 秒(精确至毫秒) */
}

void sampleKernelVersion(){
int f=0;
char buffer[80]="";
char *file="/proc/sys/kernel/version";
f = open(file, O_RDONLY);
if (f == 0)
{
printf("error to open: %s\n", file);
exit(EXIT_FAILURE);
}
read(f, (void *)buffer, 80);
buffer[strlen(buffer)-1]=0;                 /* 简单实现tr()函数的功能 */
printf("当前内核版本：\t%s\n", buffer);
close(f);
}

void sampleOsRelease(){
int f=0;
char buffer[80]="";
char *file="/proc/sys/kernel/osrelease";
f = open(file, O_RDONLY);
if (f == 0)
{
printf("error to open: %s\n", file);
exit(EXIT_FAILURE);
}
read(f, (void *)buffer, 80);
buffer[strlen(buffer)-1]=0;
printf("当前发行版本：\t%s\n", buffer);
close(f);
}

void sampleOsType(){
int f=0;
char buffer[80]="";
char *file="/proc/sys/kernel/ostype";
f = open(file, O_RDONLY);
if (f == 0)
{
printf("error to open: %s\n", file);
exit(EXIT_FAILURE);
}
read(f, (void *)buffer, 80);
buffer[strlen(buffer)-1]=0;
printf("当前操作系统：\t%s\n", buffer);
close(f);
}

void sampleDiskStat(){
int i;
FILE *fp;
int nread=0;
ssize_t len = 0;
char *buffer=NULL;
char buf[20][32];
char *file="/proc/diskstats";
char *p;
fp = fopen(file, "rb");
if (fp == NULL)
{
printf("error to open: %s\n", file);
exit(EXIT_FAILURE);
}
printf("  磁盘  读次数  写次数\n");
while((nread = getline(&buffer, &len, fp)) != -1) { /* 简单实现读行的功能 */
sscanf(buffer, "%04s%08s%s %s %s %s %s %s %s %s %s %s %s %s",
&buf[0],&buf[1],&buf[2],&buf[3],&buf[4],&buf[5],&buf[6],
&buf[7],&buf[8],&buf[9],&buf[10],&buf[11],&buf[12],&buf[13]);
if ((p=strstr(buf[2], "loop"))!=NULL)
{
;                                   /* loop本地回路不作操作 */
}
else {
printf("%06s%08s%08s\n",
&buf[2],&buf[3], &buf[7]);
}
}
}

void sampleProcesses(void)
{
FILE *fp;
int nread=0;
ssize_t len = 0;
char *buf=NULL;
char *buffer=NULL;
char *file="/proc/stat";
fp = fopen(file, "rb");
if (fp == NULL)
{
printf("error to open: %s\n", file);
exit(EXIT_FAILURE);
}
while((nread = getline(&buffer, &len, fp)) != -1) {
if((buf=strstr(buffer, "processes"))!=NULL)  /* 简单实现grep的功能 */
break;
}
buffer[strlen(buffer)-1]=0;                 /* 简单实现tr()函数的功能 */
char count[16]="";
sscanf(buffer, "%s%s", count, count);
printf("执行线程数目:\t%s\n", count);
}

void sampleContext(void)
{
FILE *fp;
int nread=0;
ssize_t len = 0;
char *buf=NULL;
char *buffer=NULL;
char *file="/proc/stat";
fp = fopen(file, "rb");
if (fp == NULL)
{
printf("error to open: %s\n", file);
exit(EXIT_FAILURE);
}
while((nread = getline(&buffer, &len, fp)) != -1) {
if((buf=strstr(buffer, "ctxt"))!=NULL)  /* 简单实现grep的功能 */
break;
}
buffer[strlen(buffer)-1]=0;                 /* 简单实现tr()函数的功能 */
char count[16]="";
sscanf(buffer, "%s%s", count, count);
printf("上下文切换次数:\t%s\n", count);
}

void sampleMeminfo()
{
FILE *fp;
int nread=0;
ssize_t len = 0;
char *buf=NULL;
char *buffer=NULL;
char *file="/proc/meminfo";
char content[16]="";
fp = fopen(file, "rb");
if (fp == NULL)
{
printf("error to open: %s\n", file);
exit(EXIT_FAILURE);
}
while((nread = getline(&buffer, &len, fp)) != -1) {
if((buf=strstr(buffer, "MemTotal"))!=NULL)  /* 简单实现grep的功能 */
{
buffer[strlen(buffer)-1]=0;             /* 简单实现tr()函数的功能 */
sscanf(buffer, "%s%s", content, content);
int memtotal_kb=(int)(strtof(content, NULL));
printf("内存总容量:\t%dG%4dM %4dK\n",
memtotal_kb/(1024*1024),           /* Gb */
(memtotal_kb/(1024))%1024,         /* Mb */
(memtotal_kb%(1024*1024))%1024);   /* Kb */
}
if((buf=strstr(buffer, "MemFree"))!=NULL)  /* 简单实现grep的功能 */
{
buffer[strlen(buffer)-1]=0;                 /* 简单实现tr()函数的功能 */
sscanf(buffer, "%s%s", content, content);
int memfree_kb=(int)(strtof(content, NULL));
printf("内存可用容量:\t%dG%4dM %4dK\n",
memfree_kb/(1024*1024),           /* Gb */
(memfree_kb/(1024))%1024,         /* Mb */
(memfree_kb%(1024*1024))%1024);   /* Kb */
}
if((buf=strstr(buffer, "SwapTotal"))!=NULL)  /* 简单实现grep的功能 */
{
buffer[strlen(buffer)-1]=0;                 /* 简单实现tr()函数的功能 */
sscanf(buffer, "%s%s", content, content);
int swaptotal_kb=(int)(strtof(content, NULL));
printf("SWAP总容量:\t%dG%4dM %4dK\n",
swaptotal_kb/(1024*1024),           /* Gb */
(swaptotal_kb/(1024))%1024,         /* Mb */
(swaptotal_kb%(1024*1024))%1024);   /* Kb */
}
if((buf=strstr(buffer, "SwapFree"))!=NULL)  /* 简单实现grep的功能 */
{
buffer[strlen(buffer)-1]=0;                 /* 简单实现tr()函数的功能 */
sscanf(buffer, "%s%s", content, content);
int swapfree_kb=(int)(strtof(content, NULL));
printf("SWAP可用容量:\t%dG%4dM %4dK\n",
swapfree_kb/(1024*1024),           /* Gb */
(swapfree_kb/(1024))%1024,         /* Mb */
(swapfree_kb%(1024*1024))%1024);   /* Kb */
break;                              /* 所需的信息已满足，退出循环 */
}
}
}
/*
* ===  FUNCTION  ======================================================================
*         Name:  main
*  Description:
* =====================================================================================
*/
int main ( int argc, char *argv[] )
{
printf(">>>系统负载<<<\n");
sampleLoadAvg();
printf("----------------------------------------\n");
printf("\n");
printf(">>>运行时间<<<\n");
sampleTime();
printf("\n");
printf(">>>版本信息<<<\n");
sampleOsType();
sampleOsRelease();
sampleKernelVersion();
printf("----------------------------------------\n");
printf("\n");
printf(">>>磁盘信息<<<\n");
sampleDiskStat();
printf("----------------------------------------\n");
printf("\n");
printf(">>>上下文切换<<<\n");
sampleContext();
printf("----------------------------------------\n");
printf("\n");
printf(">>>线程数目<<<\n");
sampleProcesses();
printf("----------------------------------------\n");
printf("\n");
printf(">>>内存信息<<<\n");
sampleMeminfo();
printf("----------------------------------------\n");
return EXIT_SUCCESS;
}