实现Linux下的ls -l命令

基本实现了Linux下的ls -l命令,对于不同的文件显示不同的颜色和显示符号链接暂时没有实现:

 /*************************************************************************
     > File Name: dirwalk.c
     > Author:
     > Mail:
     > Created Time: Tue 31 Mar 2015 11:56:38 AM CST
  ************************************************************************/

 #include<stdio.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
 #include <dirent.h>
 #include <time.h>

 #define MAX_PATH 1024
 #define MODE_LEN 10
 #define TIME_LEN 20
 #define NAME_LEN 30

 unsigned long  ugo_mode[] = {S_IRUSR, S_IWUSR, S_IXUSR, S_IRGRP, S_IWGRP, S_IXGRP, S_IROTH, S_IWOTH, S_IXOTH};
 char* rwx[] = {"r", "w", "x"};
 char* userpath = "/etc/passwd";
 char* grouppath = "/etc/group";

 /*dirwalk: apply fcn to all files in dir */
 void dirwalk(char* dir, void(*fcn)(char*))
 {
     struct dirent *dp;
     DIR* dfd;

     char name[MAX_PATH];
     if((dfd = opendir(dir)) == NULL)
     {
         fprintf(stderr, "dirwalk: can't open %s\n", dir);
         return;
     }

     while((dp = readdir(dfd)) != NULL)
     {
         if(strcmp(dp->d_name, ".") ==  || strcmp(dp->d_name, "..") == )
         {
             continue;
         }

         if(strlen(dir) + strlen(dp->d_name) +  > sizeof(name))
         {
             fprintf(stderr, "%s/%s too long\n", dir, dp->d_name);
         }else
         {
             sprintf(name, "%s/%s", dir, dp->d_name);
             (*fcn)(name);
         }
     }
     closedir(dfd);
 }

 /*getname: get the name of the user and the name of the group name */
 void getname(char* path, int id, char* name)
 {   

     int fd, save_fd;
     if((fd = open(path, O_RDONLY)) < )
     {
         perror("open \n");
         exit();
     }

     save_fd = dup(STDIN_FILENO);
     dup2(fd, STDIN_FILENO);
     close(fd);
     char p[MAX_PATH];
     char usrid[];
     sprintf(usrid, "%d", id);
     char* puid;
     while((scanf("%s", p)) != EOF)
     {
         if((puid = strstr(p, usrid)) != NULL)
         {
             char* pFlag;
             char* pResult;
             if((pFlag = strstr(p, ":")) != NULL)
             {
                 pResult = pFlag;
                 pFlag = strstr(pFlag + , ":");
             }
             if(pFlag != NULL)
             {
                 if((memcmp(pFlag + , puid, strlen(usrid))) == )
                 {
                     *pResult = '\0';
                     strcpy(name, p);
                 }
             }
             //printf("%s\n", puid);
         }
     }

     dup2(save_fd, STDIN_FILENO);
     close(save_fd);
 }

 /*getmode: get the mode of a file in string format  by st_mode */
 void getmode(unsigned long  st_mode, char* mode)
 {
     switch(st_mode & S_IFMT)
     {
         case S_IFDIR:
             mode[] = 'd';
             break;
         case S_IFIFO:
             mode[] = 'p';
             break;
         case S_IFBLK:
             mode[] = 'b';
             break;
         case S_IFCHR:
             mode[] = 'c';
             break;
         case S_IFREG:
             mode[] = '-';
             break;
         case S_IFLNK:
             mode[] = 'l';
             break;
         case S_IFSOCK:
             mode[] = 's';
             break;
         default:
             mode[] = 'u';
             break;
     }

     int i;
     for(i = ; i < ; ++i)
     {
         if(st_mode & ugo_mode[i])
         {
             strcat(mode, rwx[i % ]);
         }else
         {
             strcat(mode, "-");
         }
     }
 }

 /*gettime: get the time in string format */
 void gettime(const time_t ct, char* time)
 {
     char* tmp = ctime(&ct);
     time[] = tmp[];
     time[] = tmp[];
     time[] = tmp[];
     time[] = ' ';

     struct tm* tm_buf = gmtime(&ct);
     char last[];
     sprintf(last, "%02d %02d:%02d", tm_buf->tm_mday, tm_buf->tm_hour, tm_buf->tm_min);
     strcat(time, last);
 }

 /* print the file name and the size of the "name" */
 void fsize(char* name)
 {
     struct stat st_buf;
     if(stat(name, &st_buf) < )
     {
         fprintf(stderr, "fsize: can't access %s\n", name);
         return;
     }

     if((st_buf.st_mode & S_IFMT) == S_IFDIR)
     {
         dirwalk(name, fsize);
     }
     char* time = (char*)malloc(sizeof(char) * TIME_LEN);
     memset(time, , TIME_LEN);
     gettime(st_buf.st_atime, time);

     char* mode = (char*)malloc(sizeof(char) * MODE_LEN);
     memset(mode, , MODE_LEN);
     getmode(st_buf.st_mode, mode);

     char* username = (char*)malloc(sizeof(char) * NAME_LEN);
     memset(username, , NAME_LEN);
     getname(userpath, st_buf.st_uid, username);

     char* groupname = (char*)malloc(sizeof(char) *  NAME_LEN);
     memset(groupname, , NAME_LEN);
     getname(grouppath, st_buf.st_gid, groupname);

     printf("%s %d %s %s  %4ld %s %s\n", mode, (int)st_buf.st_nlink, username, groupname,  st_buf.st_size, time,  name);
     free(groupname);
     free(username);
     free(mode);
     free(time);
 }

 int main(int argc, char* argv[])
 {
     if(argc == )
         fsize(".");
     while(--argc)
         fsize(*++argv);
     return ;