hls.c

自己写的ls命令

//实现功能 1. ls	  2. ls -l	 3.  ls -l [若干目录或文件名]	 4. ls [若干目录或文件名]
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include<pwd.h>
#include <grp.h>

void ls_output(char dirname[],int flag);
void file_permission(int mode,char str[]);
char *uid_to_name(uid_t uid);
char *gid_to_name(gid_t gid);
void show_info(char *filename,struct stat *ptr);
void do_stat(char *filename,int flag);
void c_show_info(char *filename);
char *robchar(char *filename);
void c_rob_show_info(char *filename);
char file_type(struct stat buf);
char *count_file_name(char *filename,int count);

main(int argc,char *argv[])
{
       char cwd[1024];
	getcwd(cwd,1024);
	int flag;  
	char temp;
	
	if(argc==1)   /* ls  */
	{
		flag=0;
		ls_output(cwd,flag);
		printf("\n");
		//printf("0 none -l output\n");
	}
	else if (argc==2 && (temp=getopt(argc,argv,"l"))!=-1)  /* ls -l */
	{
		switch(temp)
			case 'l':
				{
					flag=1;
					ls_output(cwd,flag);
					printf("\n");
					//printf("1 -l output\n");
				}
	}
	else if (argc>2 && (temp=getopt(argc,argv,"l"))!=-1)    /* ls -l [若干目录或文件名]*/
		{
			flag=2;
			--argc;
			++argv;
			while(--argc)
	  				{				
						++argv;
						printf("%s:\n",*argv);
						ls_output(*argv,flag);		
						printf("\n");
	  				}
			printf("\n");
			//printf("2 -l output\n");
		}
	else                         /* ls [若干目录或文件名]*/
		{
			flag=3;
			while(--argc)
	  		{
	  			++argv;
				printf("%s:\n",*argv);	
				ls_output(*argv,flag);
				printf("\n");
	  		}
			printf("\n");
			//printf("3 non-l output\n");
		}
		
}

void ls_output(char dirname[],int flag)
{
	//printf("filename:%s",dirname);
	DIR *dir;
	struct dirent *p_dirent;
	char tempname[1000];
	struct stat buf;
	if(lstat(dirname,&buf)==-1)
		perror(dirname);
	else
	{
		//if (file_type(buf)!='d') do_stat(dirname,flag);
		if (file_type(buf)=='-') do_stat(dirname,flag);
		else if (file_type(buf)!='-' && (dir=opendir(dirname))==NULL)
			fprintf(stderr,"hls: %s: No such file or directory \n",dirname);
		else
		{
			while((p_dirent=readdir(dir))!=NULL)
			{
				if(p_dirent->d_name[0]=='.') continue;
				switch (flag)
				{
					case 0:
					case 1:
						do_stat(p_dirent->d_name,flag);
						break;
					case 2:
					case 3:
						strcpy(tempname,dirname);
						strcat(tempname,"/");
						strcat(tempname,p_dirent->d_name);
						//printf("%s\n",tempname);
						do_stat(tempname,flag);
						break;
					
				}
			
			}			
			closedir(dir);
		}
	}
}

/* 文件类型和权限 */
void file_permission(int mode,char str[])
{
	strcpy(str,"----------");
	if(S_ISREG(mode)) str[0]='-';
	if(S_ISDIR(mode)) str[0]='d';
	if(S_ISCHR(mode)) str[0]='c';
	if(S_ISBLK(mode)) str[0]='b';
	if( S_ISLNK(mode) ) str[0] = 'l';
	
	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 *ptr;
	ptr=getpwuid(uid);
	return ptr->pw_name;
}

char *gid_to_name(gid_t gid)
{
	struct group *ptr;
	ptr=getgrgid(gid);
	return ptr->gr_name;
}

void l_show_info(char *filename,struct stat *ptr)
{
	char modestr[11];
	file_permission(ptr->st_mode,modestr);
	printf("%s",modestr);
	printf("%4d  ",(int)ptr->st_nlink);
	printf("%-8s  ",uid_to_name(ptr->st_uid));
	printf("%-8s  ",gid_to_name(ptr->st_gid));
	printf("%8ld  ",(long)ptr->st_size);
	printf("%.12s  ",4+ctime(&ptr->st_mtime));
	printf("%s\n",filename);
}

/* 删除字符串中的'/' */
char *robchar(char *filename)
{
	char *p=filename;
	while(*p!='/' && *p!='\0')
		p++;
	if (*p=='/') return p+1;
	else return filename;
}

void c_show_info(char *filename)
{
	char *tmp;
	tmp=robchar(filename);
	printf("%s   ",tmp );
}

void c_rob_show_info(char *filename)
{
	printf("%s\n",filename);
}

void do_stat(char *filename,int flag)
{
	struct stat buf;
	char ftype;
	int rl;//
	char lname[128];
	char *truelname;//
       char *p=NULL,*q=NULL;
	if(lstat(filename,&buf)==-1)
		perror(filename);
	else
	{
		ftype=file_type(buf);
		switch (flag)
		{
			case 0:
				c_rob_show_info(filename);break;
			case 3:
				c_show_info(filename);break;
			case 1:
				l_show_info(filename,&buf);break;
			case 2:
				if (ftype=='l') 
				{
					rl=readlink(filename,lname,128);
					
					//readlink(filename,lname,128);
					truelname=count_file_name(lname,rl);
					p=robchar(filename);
					strcat(p,"->");
					strcat(p,truelname);
					//strcat(p,lname);
					l_show_info(p,&buf);break;
				}
				else 
					{
						p=robchar(filename);
						l_show_info(p,&buf);break;
					}
		}	
	}
}

/*文件类型*/
char file_type(struct stat buf)
{
	char ftype;
	if( S_ISREG(buf.st_mode) ) ftype = '-';
	if( S_ISDIR(buf.st_mode) ) ftype = 'd';
	//if(S_ISCHR(buf.st_mode)) ftype='c';
	if( S_ISLNK(buf.st_mode) ) ftype = 'l';
	return ftype;
}

/* 截取readlink函数返回字符串中的有效部分 */
char *count_file_name(char *filename,int count)
{
	char *p=filename;
	char *q=filename;
	int i=0;
	while(i++<count)
		p++;
	*p='\0';
	return q;
}