ls命令的简单实现

目标：简单的实现ls命令

实现的mic_ls命令主要功能

1.循环遍历目录

2.列出目标目录所有的子目录和文件

3.列出文件的文件权限，所有者，文件大小等详细信息

参数

-r 循环遍历

-a 列出全部文件

-l 列出详细信息(文件类型、权限。。。)

环境

ubuntu 14.04 gcc.real (Ubuntu 4.8.2-19ubuntu1) 4.8.2

代码

新手菜鸟 如有错误 欢迎指正

#include<stdio.h>

#include<unistd.h>

#include<stdlib.h>

#include<stdbool.h>

#include<dirent.h>

#include<string.h>

#include<sys/stat.h>

#include<pwd.h>

#include<grp.h>

bool show_all=false;

bool show_list=false;

bool show_recursion=false;

void do_ls_r(char *pathname,int depth);

void do_ls(char *pathname);

int judge_dir(char *pathname);

void do_showlist(DIR *dp);

void mode_to_letters(int mode,char str[]);

char *uid_to_name(uid_t uid);

char *gid_to_name(gid_t gid);

int main(int argc,char *argv[])

{

	int opt;

	while((opt=getopt(argc,argv,"arl"))!=-1){

		switch(opt){

			case 'a':

				show_all=true;

				break;

			case 'r':

				show_recursion=true;

				break;

			case 'l':

				show_list=true;

				break;

			case '?':

				printf("unknow option :%c\n",optopt);

				exit(1);

		}

	}

	if(show_recursion){

		if(argc==optind)

		  do_ls_r(".",4);

		else{

			for(;optind<argc;optind++){

				if(judge_dir(argv[optind])){

					printf("%s:\n",argv[optind]);

				    do_ls_r(argv[optind],4);

				}

				else{

					printf("not a directory!\n");

					exit(1);

				}

			}

		}

	}

	else{

		if(argc==optind)

		  do_ls(".");

		else{

			for(;optind<argc;optind++){

				if(judge_dir(argv[optind])){

					printf("%s:\n",argv[optind]);

				    do_ls(argv[optind]);

				}

				else{

					printf("not a directory!\n");

					exit(1);

				}

			}

		}

	}

}

int judge_dir(char *pathname)

{

	struct stat statbuf;

	if((lstat(pathname,&statbuf))<0){

	  printf("error in lstat!\n");

	  exit(1);

	}

	if(S_ISDIR(statbuf.st_mode))

	  return 1;

	else

	  return -1;

}

void do_ls_r(char *pathname,int depth)

{

	DIR *dp;

	struct dirent *entry;

	struct stat statbuf;

	if((dp=opendir(pathname))==NULL){

		printf("can't open dir:%s\n",pathname);

		exit(1);

	}

	chdir(pathname);

	while((entry=readdir(dp))!=NULL){

		lstat(entry->d_name,&statbuf);

		if(S_ISDIR(statbuf.st_mode)){

			if(strcmp(".",entry->d_name)==0||strcmp("..",entry->d_name)==0)

			  continue;

			printf("%*s%s/\n",depth," ",entry->d_name);

			do_ls_r(entry->d_name,depth+4);

		}

		else

		  printf("%*s%s\n",depth," ",entry->d_name);

	}

	chdir("..");

	closedir(dp);

}

void do_ls(char *pathname)

{

	DIR *dp;

	struct dirent *entry;

	if((dp=opendir(pathname))==NULL){

			printf("can't open dir:%s\n",pathname);

			exit(1);

		}

	if(show_list){

		chdir(pathname);

	    do_showlist(dp);

	}

	else{

			while((entry=readdir(dp))!=NULL){

			if(!show_all)

			  if(*(entry->d_name)=='.')

				continue;

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

		}

		closedir(dp);

	}

}

void do_showlist(DIR *dp)

{

	struct dirent *entry;

	struct stat statbuf;

	char l_mode[11];

	while((entry=readdir(dp))!=NULL){

		if((lstat(entry->d_name,&statbuf))<0){

			printf("error :in lstat\n");

			exit(1);

		}

		if(!show_all)

		  if(*(entry->d_name)=='.')

			continue;

		mode_to_letters(statbuf.st_mode,l_mode);

		printf("%s",l_mode);

		printf("%4d ",(int)statbuf.st_nlink);

		printf("%-8s ",uid_to_name(statbuf.st_uid));

        printf("%-8s ",gid_to_name(statbuf.st_gid));

		printf("%8ld ",(long)statbuf.st_size);

		printf("    %s ",entry->d_name);

		printf("\n");

	}

}

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;

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

	  return (pw_ptr->pw_name);

	else

	  return NULL;

}

char *gid_to_name(gid_t gid)

{

	struct group *getgrid,*grp_ptr;

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

	  return (grp_ptr->gr_name);

	else

	  return NULL;

}

ls命令的简单实现的相关教程结束。