1、学习任务

参考伪代码实现ls的功能,提交代码的编译,运行结果截图,码云代码链接

打开目录文件
针对目录文件
读取目录条目
显示文件名
关闭文件目录文件

2、ls功能

ls:显示文件目录列表

  • -a:显示所有的文件,包括隐藏文件
  • -l:列出长数据串,显示出文件的属性与权限等数据信息(常用)
  • -i:结合-l参数列出每个文件的inode
  • -d:仅列出目录本身,而不是列出目录里的内容列表

3、代码

include <stdio.h>

#include <sys/types.h>  

#include <dirent.h>  

#include <sys/stat.h>  

#include <pwd.h>  

#include <grp.h>  

#include <unistd.h>  

#include <string.h>  

  

#define LS_NONE 0  

#define LS_L 101  

#define LS_R 102  

#define LS_D 103  

#define LS_I 104  

  

#define LS_A 200  

  

#define LS_AL (LS_A+LS_L)  

#define LS_AI (LS_A+LS_I)  

  

// 展示单个文件的详细信息  

void show_file_info(char* filename, struct stat* info_p)  

{  

    char* uid_to_name(), *ctime(), *gid_to_name(), *filemode();  

    void mode_to_letters();  

    char modestr[11];  

    mode_to_letters(info_p->st_mode, modestr);  

  

    printf("%s", modestr);  

    printf(" %4d", (int) info_p->st_nlink);  

    printf(" %-8s", uid_to_name(info_p->st_uid));  

    printf(" %-8s", gid_to_name(info_p->st_gid));  

    printf(" %8ld", (long) info_p->st_size);  

    printf(" %.12s", 4 + ctime(&info_p->st_mtime));  

    printf(" %s\n", filename);  

}  

  

void mode_to_letters(int mode, char str[])  

{  

    strcpy(str, "----------");  

  

    if (S_ISDIR(mode))  

    {  

        str[0] = 'd';  

    }  

  

    if (S_ISCHR(mode))  

    {  

        str[0] = 'c';  

    }  

  

    if (S_ISBLK(mode))  

    {  

        str[0] = 'b';  

    }  

  

    if ((mode & S_IRUSR))  

    {  

        str[1] = 'r';  

    }  

  

    if ((mode & S_IWUSR))  

    {  

        str[2] = 'w';  

    }  

  

    if ((mode & S_IXUSR))  

    {  

        str[3] = 'x';  

    }  

  

    if ((mode & S_IRGRP))  

    {  

        str[4] = 'r';  

    }  

  

    if ((mode & S_IWGRP))  

    {  

        str[5] = 'w';  

    }  

  

    if ((mode & S_IXGRP))  

    {  

        str[6] = 'x';  

    }  

  

    if ((mode & S_IROTH))  

    {  

        str[7] = 'r';  

    }  

  

    if ((mode & S_IWOTH))  

    {  

        str[8] = 'w';  

    }  

  

    if ((mode & S_IXOTH))  

    {  

        str[9] = 'x';  

    }  

}  

  

char* uid_to_name(uid_t uid)  

{  

    struct passwd* getpwuid(),* pw_ptr;  

    static char numstr[10];  

  

    if((pw_ptr = getpwuid(uid)) == NULL)  

    {  

        sprintf(numstr,"%d",uid);  

  

        return numstr;  

    }  

    else  

    {  

        return pw_ptr->pw_name;  

    }  

}  

  

char* gid_to_name(gid_t gid)  

{  

    struct group* getgrgid(),* grp_ptr;  

    static char numstr[10];  

  

    if(( grp_ptr = getgrgid(gid)) == NULL)  

    {  

        sprintf(numstr,"%d",gid);  

        return numstr;  

    }  

    else  

    {  

        return grp_ptr->gr_name;  

    }  

}  

  

void do_ls(char dirname[],int mode)  

{  

    DIR* dir_ptr;  

    struct dirent* direntp;  

  

    if ((dir_ptr = opendir(dirname)) == NULL)  

    {  

        fprintf(stderr, "ls2: cannot open %s \n", dirname);  

    }  

    else  

    {  

        if(mode==LS_D)  

        {  

            printf("%s\n", dirname);  

        }  

        else  

        {  

            char dirs[20][100];  

            int dir_count = 0;  

              

            while ((direntp = readdir(dir_ptr)) != NULL)  

            {  

  

                if(mode < 200 && direntp->d_name[0]=='.')  

                {  

                    continue;  

                }  

  

                char complete_d_name[200];  // 文件的完整路径  

                strcpy (complete_d_name,dirname);  

                strcat (complete_d_name,"/");  

                strcat (complete_d_name,direntp->d_name);  

                  

                struct stat info;  

                if (stat(complete_d_name, &info) == -1)  

                {  

                    perror(complete_d_name);  

                }  

                else  

                {  

                    if(mode == LS_L||mode == LS_AL)  

                    {  

                        show_file_info(direntp->d_name, &info);  

                    }  

                    else if(mode == LS_A||mode == LS_NONE||mode == LS_I||mode == LS_AI)  

                    {  

                        if(mode == LS_I||mode == LS_AI)  

                        {  

                            printf("%llu ", direntp->d_ino);  

                        }  

  

                        printf("%s\n", direntp->d_name);  

                    }  

                    else if(mode == LS_R)  

                    {  

  

                        if(S_ISDIR(info.st_mode))  

                        {  

                            printf("%s\n", direntp->d_name);  

  

                            strcpy (dirs[dir_count],complete_d_name);  

                            dir_count++;  

                        }  

                        else  

                        {  

                            printf("%s\n", direntp->d_name);  

                        }  

                    }  

  

                }  

            }  

  

            if(mode == LS_R)  

            {  

                int i=0;  

                printf("\n");  

                for(;i<dir_count;i++){  

                    printf("%s:\n", dirs[i]);  

                    do_ls(dirs[i],LS_R);  

                    printf("\n");  

                }  

            }  

  

        }  

  

        closedir(dir_ptr);  

    }  

}  

  

// 解析一个单词参数,如-l,-i  

int analyzeParam(char* input){  

    if(strlen(input)==2)  

    {  

        if(input[1]=='l') return LS_L;  

        if(input[1]=='a') return LS_A;  

        if(input[1]=='d') return LS_D;  

        if(input[1]=='R') return LS_R;  

        if(input[1]=='i') return LS_I;  

    }  

    else if(strlen(input)==3)  

    {  

        if(input[1]=='a'&& input[2]=='l') return LS_AL;  

        if(input[1]=='a'&& input[2]=='i') return LS_AI;  

    }  

    return -1;  

}  

  

int main(int ac,char* av[])  

{  

  

    if(ac == 1)  

    {  

        do_ls(".",LS_NONE);  

    }  

    else  

    {  

        int mode = LS_NONE; // 默认为无参数ls  

        int have_file_param = 0; // 是否有输入文件参数  

  

        while(ac>1)  

        {  

            ac--;  

            av++;  

  

            int calMode = analyzeParam(*av);  

            if(calMode!=-1)  

            {  

                mode+=calMode;  

            }  

            else  

            {  

                have_file_param = 1;  

                do  

                {  

                    printf("%s:\n", *av);  

                    do_ls(*av,mode);  

                    printf("\n");  

  

                    ac--;  

                    av++;  

                }while(ac>=1);  

            }  

        }  

  

        if (!have_file_param)  

        {  

            do_ls(".",mode);  

        }  

          

    }       

}  

4、测试实现mystat

posted on 2019-12-28 12:31  20175328李欣颖  阅读(243)  评论(0编辑  收藏  举报