〖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=;
     char buffer[]="";                         /* 定义字符串并初始化为'\0' */
     char buf[][];
     char *file="/proc/loadavg";
     f = open(file, O_RDONLY);
     if (f == )
     {
         printf("error to open: %s\n", file);
         exit(EXIT_FAILURE);
     }
     read(f, (void *)buffer, );
     sscanf(buffer, "%s %s %s %s %s",            /* sscanf()拆分成多个字符串 */
             &buf[],&buf[],&buf[],&buf[],&buf[]);
     printf("一分钟平均负载：%s\n", buf[]);
     printf("五分钟平均负载：%s\n", buf[]);
     printf("一刻钟平均负载：%s\n", buf[]);
     printf("采样时刻的间隔：%s\n", buf[]);
     printf("最大线程的数目：%s\n", buf[]);
     close(f);
 }
 void sampleTime(){
     int f=;
     char buffer[]="";
     char buf[][];
     float seconds=;
     float secondr=;
     char *file="/proc/uptime";
     f = open(file, O_RDONLY);
     if (f == )
     {
         printf("error to open: %s\n", file);
         exit(EXIT_FAILURE);
     }
     read(f, (void *)buffer, );
     sscanf(buffer, "%s %s", &buf[], &buf[]);
     close(f);
     printf("系统运行时间：\t%s秒\n", buf[]);
     printf("系统空闲时间：\t%s秒\n", buf[]);
     close(f);
     seconds=strtof(buf[],NULL);
     secondr=strtof(buf[],NULL);
     printf("系统运行时间：\t%03d天%02d时%02d分%02.6f秒\n",
             (int)seconds/(*),             /* 天 */
             ((int)seconds/())%(),         /* 时 */
             ((int)seconds/)%,               /* 分 */
             ((int)seconds%)+(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/(*),             /* 天 */
             ((int)secondr/())%(),         /* 时 */
             ((int)secondr/)%,               /* 分 */
             ((int)secondr%)+(secondr-(int)secondr)); /* 秒(精确至毫秒) */
 }

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

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

 void sampleDiskStat(){
     int i;
     FILE *fp;
     int nread=;
     ssize_t len = ;
     char *buffer=NULL;
     char buf[][];
     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)) != -) { /* 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[],&buf[],&buf[],&buf[],&buf[],&buf[],&buf[],
                 &buf[],&buf[],&buf[],&buf[],&buf[],&buf[],&buf[]);
         if ((p=strstr(buf[], "loop"))!=NULL)
         {
             ;                                   /* loop本地回路不作操作 */
         }
         else {
             printf("%06s%08s%08s\n",
                     &buf[],&buf[], &buf[]);
         }
     }
 }

 void sampleProcesses(void)
 {
     FILE *fp;
     int nread=;
     ssize_t len = ;
     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)) != -) {
         if((buf=strstr(buffer, "processes"))!=NULL)  /* 简单实现grep的功能 */
             break;
     }
     buffer[strlen(buffer)-]=;                 /* 简单实现tr()函数的功能 */
     char count[]="";
     sscanf(buffer, "%s%s", count, count);
     printf("执行线程数目:\t%s\n", count);
 }

 void sampleContext(void)
 {
     FILE *fp;
     int nread=;
     ssize_t len = ;
     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)) != -) {
         if((buf=strstr(buffer, "ctxt"))!=NULL)  /* 简单实现grep的功能 */
             break;
     }
     buffer[strlen(buffer)-]=;                 /* 简单实现tr()函数的功能 */
     char count[]="";
     sscanf(buffer, "%s%s", count, count);
     printf("上下文切换次数:\t%s\n", count);
 }

 void sampleMeminfo()
 {
     FILE *fp;
     int nread=;
     ssize_t len = ;
     char *buf=NULL;
     char *buffer=NULL;
     char *file="/proc/meminfo";
     char content[]="";
     fp = fopen(file, "rb");
     if (fp == NULL)
     {
         printf("error to open: %s\n", file);
         exit(EXIT_FAILURE);
     }
     while((nread = getline(&buffer, &len, fp)) != -) {
         if((buf=strstr(buffer, "MemTotal"))!=NULL)  /* 简单实现grep的功能 */
         {
             buffer[strlen(buffer)-]=;             /* 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/(*),           /* Gb */
                     (memtotal_kb/())%,         /* Mb */
                     (memtotal_kb%(*))%);   /* Kb */
         }
         if((buf=strstr(buffer, "MemFree"))!=NULL)  /* 简单实现grep的功能 */
         {
             buffer[strlen(buffer)-]=;                 /* 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/(*),           /* Gb */
                     (memfree_kb/())%,         /* Mb */
                     (memfree_kb%(*))%);   /* Kb */
         }
         if((buf=strstr(buffer, "SwapTotal"))!=NULL)  /* 简单实现grep的功能 */
         {
             buffer[strlen(buffer)-]=;                 /* 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/(*),           /* Gb */
                     (swaptotal_kb/())%,         /* Mb */
                     (swaptotal_kb%(*))%);   /* Kb */
         }
         if((buf=strstr(buffer, "SwapFree"))!=NULL)  /* 简单实现grep的功能 */
         {
             buffer[strlen(buffer)-]=;                 /* 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/(*),           /* Gb */
                     (swapfree_kb/())%,         /* Mb */
                     (swapfree_kb%(*))%);   /* 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;
 }