homework.c

操作系统内核实习

#include<stdio.h>
#include<fcntl.h>
#include<string.h>
#include<stdlib.h>
main()
{
     int  flag=1;
//the flag to distinguish between "quit" and other dictate
     char statement[10];//statement can only in 10 rooms
     char filename[20];//name can only in 20 rooms
     char filename1[20];//for copying
     char dictate[50];//The dictate user tell
     char *tokenPtr;
     int  str;
     int  h;
//user's dictate,now separate into two parts
     int  s;
     int  d;
     int  f;
//initial array 
     int  k;//for getchar(),connect with content[]
     int  fd;//file needs parameter
     int  fd1;//for copying
     char content[100];//content,can sustain with reuse
     char fg[10];
//work with reading and writing 
     char use[100];
     int  i=0;
     int  j;
     int  ptr=0;
//for transfering with system     
     char commend[10];
//use for "man"
     int fl;
 while(flag==1)
     {
       h=0;//the most important in initial,or it will cause two dictate wrong
      for(s=0;s<50;s++)
          dictate[s]=NULL;
      for(d=0;d<10;d++)
          statement[d]=NULL;
      for(f=0;f<20;f++)
          filename[f]=NULL;
//initial array
     printf("Please tell the dictate:\n");
     while((str=getchar())!=10)
     {
         (int)dictate[h]=str;
          h=h+1;
     }
     tokenPtr=strtok(dictate," ");
     strcpy(statement,tokenPtr);
     //to solute the one dictate or with filename question
     //when meet " vi" "read""write"
     //then the copy the filename to array
//separate the dictate
          if(strcmp(statement,"quit")==0)
          {
            flag=0;
          }//the flag to quit the shell program
          if(strcmp(statement,"vi")==0)
          {
            tokenPtr=strtok(NULL," ");
            strcpy(filename,tokenPtr);//copy the filename
            fd= open(filename,O_CREAT,0666);
            close(fd);
            printf("The file is correctly created!!\n");
          }
          if(strcmp(statement,"write")==0)
          {
            tokenPtr=strtok(NULL," ");
            strcpy(filename,tokenPtr);//copy the filename
            fd=open(filename,O_APPEND|O_WRONLY,0666);//
            if(fd>=0)
            {
            printf("Please give the context,press Esc to quit:\n");
              while((k=getchar())!=27)//while if getchar isn't Esc
              {
               if(i==100)//the content beyond the mark
                 {
                 i=0;
                 write(fd,content,100);  
                 }//clear i,write the content
                 content[i++]=k;//put k into the array
              }
              content[i]='\0';//end 
              write(fd,content,i);
              close(fd);
              getchar();//for soluting the question
              //this is the most important sentence 
              printf("The content is correctly written!! \n");
            }
            else printf("The file isn't exist!!\n");
          }
          if(strcmp(statement,"read")==0)
          {
            fl=0;
            tokenPtr=strtok(NULL," ");
            strcpy(filename,tokenPtr);//copy the filename
            fd=open(filename,O_APPEND|O_RDONLY,0666);   
            if(fd>=0)
            { 
              while(fl==0)
              {
                 for(k=0;k<=9;k++)
                 fg[k]=NULL;
                 read(fd,fg,10);
                 for(k=0;k<=9;k++)
                 {
                     if(fg[k]==NULL)
                     {
                     fl=1;
                     continue;
                     }
                     printf("%c",fg[k]);
                 }
              }
            close(fd);
            }
            else printf("The file isn't exist!!\n");
          }
          if(strcmp(statement,"copy")==0)
          {
            fl=0;
            tokenPtr=strtok(NULL," ");
            strcpy(filename,tokenPtr);//copy info from the file//for reading
            tokenPtr=strtok(NULL," ");//copy info to the file1//for writing
            strcpy(filename1,tokenPtr);
            fd=open(filename,O_APPEND|O_RDONLY,0666);//for reading
            fd1=open(filename1,O_APPEND|O_WRONLY,0666);//for writing
            if(fd>=0)
            {
               if(fd1>=0)
               {
                  while(fl==0)
                  {
                     for(k=0;k<=99;k++)
                     {
                     content[k]=NULL;
                     }//reuse the buffer
                     read(fd,content,100);//read 100 rooms from the file
                     for(k=0;k<=99;k++)
                     {
                       if(content[k]==NULL)
                       {  
                            i=1;
                            content[k]='\0'; 
                       }  
                     }//search the buffer,
                     if(i==0)//define outside
                       write(fd1,content,100);
                     else
                     {
                       write(fd1,content,k);
                       fl=1;
                       printf("The action 'copy' has successful been done!\n");
                       continue;   
                     }            
                  }
               }
            }
            else printf("The file isn't exist!!\n");
            close(fd);
            close(fd1);
          }
          if(strcmp(statement,"rm")==0)
          {
            tokenPtr=strtok(NULL," ");
            strcpy(filename,tokenPtr);
            printf("Are you sure to remove this file(Y/N):\n");
            if(getchar()=='Y')
            {
            use[0]='r';use[1]='m';use[2]=' ';use[3]='\0';
            strcat(use,filename);
            system(use);
            printf("The file is successly delete!!\n");
            }
            getchar();
          }//use system to finish function "rm" 
          if(strcmp(statement,"ls")==0)
          {
            printf("The file in the path is: \n");
            use[0]='l';use[1]='s';use[2]='\0';
            system(use);
          }//use fork() to finish function "ls"
          if(strcmp(statement,"Ls")==0)
          {
            tokenPtr=strtok(NULL," ");
            strcpy(filename,tokenPtr);
            use[0]='l';use[1]='s';use[2]=' ';use[3]='\0';
            strcat(use,filename);
            system(use);
          }
          if(strcmp(statement,"help")==0)
          {
            printf("The statements in the Model Shell are:\n");
            printf("vi  write  read  rm  ls  quit  help  man  Ls copy \n");
          }//introduce to My shell
	  if(strcmp(statement,"man")==0)
          {
            tokenPtr=strtok(NULL," ");
            strcpy(commend,tokenPtr);
            if(strcmp(commend,"vi")==0)
            {
            printf("This commend will creat a new file!!\n");
            printf("Format is like this:vi filename/path filename\n");
            printf("That will clue the message!\n");
            }
            if(strcmp(commend,"write")==0)
            {
            printf("This commend will write a file!!\n");
            printf("Format is like this:write filename\n");
            printf("Ask you to tell the content,pass Esc to esc!!\n");
            }
            if(strcmp(commend,"read")==0)
            {
            printf("This commend will read a file for you\n");
            printf("Format is like this:read filename\n");
            printf("Then will slow the content!!\n");
            }
            if(strcmp(commend,"rm")==0)
            {
            printf("This commend will delete a file!!\n");
            printf("Format is like this:rm filename\n");
            printf("That will delete the file!!\n");
            }
            if(strcmp(commend,"ls")==0)
            {
            printf("This will tell you the file in this index!!\n"); 
            }
            if(strcmp(commend,"quit")==0)
            {
            printf("This will quit My shell!!\n");
            }
            if(strcmp(commend,"help")==0)
            {
            printf("This will display the dictate in MY shell!!\n");
            }
            if(strcmp(commend,"Ls")==0)
            {
            printf("This commend will sustain display the path information!\n");
            }
            if(strcmp(commend,"copy")==0)
            {
            printf("This will copy a content to another file!!");
            }
          }
     }
     return 0;
}