操作系统第三章编程作业：UNIX Shell and History Feature

操作系统第三章编程作业：UNIX Shell and History Feature

比较核心的地方就是用二维指针数组来存储用户输入的命令行，这样即可以完成exec函数的调用，还可以使得数组具有记忆功能，进而达到题目要求的历史特征功能。

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <string.h>
#include <stdlib.h>


#define MAX_LINE 80

int length(int a[]){
    int n=0;
    while(a[n]!='\0')   n++;  //'\0'=>表示的是数组存放元素结束的标志 
    return n;
}

int main(){
    char *args[MAX_LINE][MAX_LINE];//={"ps","-ael","NULL"};
    int should_run = 1;
    int i = 0;
    int j = 0; 
    int his_i = 1;
    //char *his1[MAX_LINE];
    //char *his2[MAX_LINE];
    //char *doublehis[MAX_LINE][MAXLINE];
    for(i=0;i<MAX_LINE;i++){
        //args[i] = (char*)malloc(20*sizeof(char));
        //his1[i] = (char*)malloc(20*sizeof(char));
        //his2[i] = (char*)malloc(20*sizeof(char));
        for(j=0;j<MAX_LINE;j++){
            args[i][j] = (char*)malloc(20*sizeof(char)); 
        }
    }
    while(should_run){
        if(strcmp(args[his_i-1][0],"!!") == 0){
            if(his_i-2>0){
                for(i=0;i<5;i++){
                    args[his_i][i] = args[his_i-2][i];
                }
            }
            else{
                printf("No command in history!\n");
                i=0;
                printf("osh>");
                //int len = read(0, string, 20);
                //setup(string,args,&b);
                do{
                    scanf("%s",args[his_i][i]);
                    i++;
                }while(getchar() != '\n');       
                args[his_i][i] = NULL;
                }
        }
        else{
            i=0;
            printf("osh>");
        //int len = read(0, string, 20);
        //setup(string,args,&b);
            do{
                scanf("%s",args[his_i][i]);
                i++;
            }while(getchar() != '\n');       
            args[his_i][i] = NULL;
        }
        
        //his1[his_i] = args[0]; 
        //his2[his_i] = args;     
        
        //for(i=0;i<his_i;i++){
            //printf("%d %s\n",i+1,his1[i]);
        //}
        pid_t pid;
        pid = fork();
        if(pid < 0){
            fprintf(stderr,"Fork Failed");
            return 1;
        }       
        else if(pid == 0){
            // execlp("/bin/ls","ls",NULL);
            if(strcmp(args[his_i][0],"exit") == 0){
                should_run = 0;
                exit(0);
                return 0;               
            }        
            else if(strcmp(args[his_i][0],"history") == 0){
                for(i=his_i;(i>0)&&(i>his_i-10);i--){
                    printf("%d--%s\n",i,args[i][0]);
                }
                
            }  
            else if(strcmp(args[his_i][0],"!!") == 0){
                his_i++;
                continue;
                //char *temp[10] = {"history",0};
                //int id1 = execvp(args[his_i-1][0],args[his_i-1]);
                // int id1 = execvp(temp[0],temp);
                // if(id1 < 0){
                //     //printf("%d-%s-%s",id1,args[his_i-1][0],args[his_i-1][1]);
                //     printf("Not find command!\n");
                // }
            }       
            else{
                int id = execvp(args[his_i][0],args[his_i]);
                //int id = execvp(*his[his_i-1],his[his_i-1]);
                if(id < 0){
                    printf("Not find command!\n");
                }
            }
            //printf("%d   I am child   %d\n",getpid(),getppid());
        }
        else {
            if(args[his_i][strlen(args[his_i])-3]=="&"){
               continue;
            }
            else {
                wait(NULL);
            }
            
        }
        his_i++;
        fflush(stdout);
    }
    for(i=0;i<MAX_LINE;i++){
        //args[i] = (char*)malloc(20*sizeof(char));
        //his[i] = (char*)malloc(20*sizeof(char));
        for(j=0;j<MAX_LINE;j++){
            free(args[i][j]);
        }
        
        //free(his1[i]);
        //free(his2[i]);
    }
    return 0;
}

还未实现“！+ 数字”查找历史的功能
还有一些Bug

Continue to improve…