proc_text.c

实现模块的加载等实现。在LINUX操作系统下实现 操作系统实验程序之一

#define __NO_VERSION
#define __KERNEL__
#define MODULE

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include <asm/uaccess.h>

#define STRINGLEN     10
#define NAMELEN       10
#define IDLEN         10
#define KBUFLEN       50

 struct person_information{
        char name[NAMELEN];
        char id[IDLEN];
 };

struct person_information global_buffer[STRINGLEN];

struct proc_dir_entry *student_dir,*student_file;

int rec_count=0;
                                      
int proc_read_student(char *page,char **start,off_t off,int count,int *eof,
                          void *data)
{
    int len;
    MOD_INC_USE_COUNT;

    if(rec_count==0)//若student文件中没有内容
      {
         len=sprintf(page,"there is no record!\n");
      }

    int v;
    for(v=0;v<rec_count;v++)//有内容则打印
        {
          len=len+sprintf(page,"name is %s, id is %s \n",global_buffer[v].name,
                      global_buffer[v].id);
        }

    MOD_DEC_USE_COUNT;

    return len;
}            

int proc_write_student(struct file *file,const char *buffer,unsigned long count,
                       void *data)
{
    int len=count;
    char kbuffer[KBUFLEN];

    MOD_INC_USE_COUNT;

    char op[5];
    char name[NAMELEN];
    char id[IDLEN];
    
    copy_from_user(kbuffer,buffer,len);//将用户区命令copy到核心缓冲区
    kbuffer[len]='\0';
    
    int index=0;
    while(kbuffer[index]!='-')
         {
           op[index]=kbuffer[index];
           index++;
         }
    op[index]='\0';//将指令类型存入op
    index++;

    int i=0;
    while(kbuffer[index]!='-')
         {
           name[i]=kbuffer[index];
           i++;
           index++;
         }
           
    name[i]='\0';//学生姓名存入name
    index++;

    i=0;
    while(index<strlen(kbuffer))
         {
           id[i]=kbuffer[index];
           i++;
           index++;
         }
    id[i]='\0';//学生号存入id

    if(strcmp(op,"insert")==0)//若用户指令为插入
      {
        strcpy(global_buffer[rec_count].name,name);
        strcpy(global_buffer[rec_count].id,id);
        rec_count++;
      }
    else//若用户指令为删除
      {  
           int j;
           for(j=0;j<rec_count;j++)
              {
                if((strcmp(global_buffer[j].name,name)==0)&&
                    (strcmp(global_buffer[j].id,id)==0))
                  break;//找到要删除的
              }
           while(j<rec_count)//数组内容依次前移
              {
                strcpy(global_buffer[j].name,global_buffer[j+1].name);
                strcpy(global_buffer[j].id,global_buffer[j+1].id);
                j++;
              }
           rec_count--;
          
      }

    MOD_DEC_USE_COUNT;
    return len;
}                              
                                                                                


int init_module()
{
    student_dir=proc_mkdir("proc_text",NULL);//建立新文件夹proc_text
    student_dir->owner=THIS_MODULE;

    student_file=create_proc_entry("student",0644,student_dir);//并生成文件student
    
    student_file->read_proc=proc_read_student;
    student_file->write_proc=proc_write_student;
    student_file->owner=THIS_MODULE;

    int w;
    for(w=0;w<STRINGLEN;w++)//初始化
       {
           strcpy(global_buffer[w].name,"$$$$$$$$$");
           strcpy(global_buffer[w].id,"$$$$$$$$$");
       }

    return 0;
}

void cleanup_module()//删除文件以及文件夹
{
     remove_proc_entry("student",student_dir);
     remove_proc_entry("proc_text",NULL);
}

MODULE_LICENSE("GPL");