编程实现Linux下的ls -l

头文件

#ifndef __FUNC_H__
#define __FUNC_H__

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

#define ENT_CNT 128
#define FILE_LEN 256

int get_file_name(DIR* pdir,char* dirname ,char names[][FILE_LEN]);
void str_sort(char arr[][FILE_LEN], int cnt);
void show_ent(char name[][FILE_LEN], int cnt);
void mode_to_str(mode_t mode, char* dest);
char* time_format(char* src);

#endif

主函数

/*************************************************************************
  > File Name: func.c
  > Author: KrisChou
  > Mail: zhoujx0219@163.com
  > Created Time: Tue 19 Aug 2014 02:31:34 PM CST
 ************************************************************************/
#include "func.h"

int main(int argc, char* argv[])
{
    DIR* pdir ;
    struct dirent *pent ; 

    char file_names[ENT_CNT][FILE_LEN] ;
    int cnt ; //所遍历目录子项的个数
    char pold[128]="";  //记录程序原来的工作路径
    char pnew[128]=".";  //记录所需遍历目录的绝对路径，使用stat获取文件信息需要绝对路径（除非程序遍历当前目录）
    getcwd(pold, 128);
    if(argc == 2)
    {
        pdir = opendir(argv[1]);
        chdir(argv[1]);
        getcwd(pnew, 128);
        chdir(pold);
    }else if(argc == 1)
    {
        pdir = opendir(".");

    }else
    {
        printf("USAGE: EXE DIR \n");
        exit(1);
    }

    if(pdir == NULL)
    {
        perror("opendir");
        exit(1);
    }
    cnt = get_file_names(pdir,pnew ,file_names); //将每一项的 绝对路径(pnew) + filename 存入数组，以便stat获取文件信息
     str_sort(file_names, cnt);
    show_ent(file_names, cnt);
    return 0 ;
}

1. get_file_name

/*************************************************************************
  > File Name: ./src/get_file_name.c
  > Author: KrisChou
  > Mail:zhoujx0219@163.com
  > Created Time: Tue 19 Aug 2014 03:03:23 PM CST
 ************************************************************************/

#include "func.h"
int get_file_names(DIR* pdir, char* dirname, char names[][FILE_LEN])
{
    struct dirent* pent ;
    int cnt = 0 ;
    while( (pent = readdir(pdir)) != NULL )
    {
        if(strncmp(pent ->d_name, ".", 1) == 0 || strncmp(pent ->d_name, "..", 2) == 0)
        {
            continue ;
        }
        strcpy(names[cnt],dirname);
        strcat(names[cnt], "/");
        strcat(names[cnt], pent -> d_name);
        cnt ++ ;
    }
    closedir(pdir);
    return cnt ;

}

2. str_sort

/*************************************************************************
    > File Name: ./src/str_sort.c
    > Author: KrisChou
    > Mail:zhoujx0219@163.com
    > Created Time: Tue 19 Aug 2014 03:19:05 PM CST
 ************************************************************************/
#include "func.h"

static int my_cmp(const void* left, const void* right )
{
    return strcmp((char* )left , (char*)right);
}

void str_sort(char arr[][FILE_LEN], int cnt)
{
    qsort(arr, cnt, FILE_LEN, my_cmp);
}

3. show_ent

/*************************************************************************
  > File Name: show_ent.c
  > Author: KrisChou
  > Mail:zhoujx0219@163.com
  > Created Time: Tue 19 Aug 2014 02:36:17 PM CST
 ************************************************************************/
#include "func.h"

void show_ent(char name[][FILE_LEN], int cnt)
{
    struct stat my_stat ;
    char buf[11]="";
    char *pstr ;
    int index ;
    for(index = 0; index < cnt; index ++)
    {
        memset(&my_stat, 0, sizeof(my_stat));
        if( stat(name[index], &my_stat) == -1 )
        {
            perror("stat");
            exit (1);
        }
        mode_to_str(my_stat.st_mode, buf);
        pstr = ctime(&(my_stat.st_atime));//Mon Aug 18 14:37:40 2014
        pstr = time_format(pstr);
        printf("%10s.%2d%7s%7s%5d%13s %s\n",buf, my_stat.st_nlink, getpwuid(my_stat.st_uid)->pw_name, getgrgid(my_stat.st_gid) ->gr_name, my_stat.st_size, pstr,name[index]);

    }
}

3.1 mode_to_str

/*************************************************************************
  > File Name: mode_to_str.c
  > Author: KrisChou
  > Mail:zhoujx0219@163.com
  > Created Time: Tue 19 Aug 2014 02:32:33 PM CST
 ************************************************************************/
#include "func.h"

void mode_to_str(mode_t mode, char* dest)
{
    memset(dest,'-',10);
    if(S_ISDIR(mode))
    {
        dest[0]='d';
    }
    if(S_ISREG(mode))
    {
        dest[0]='-';
    }

    if(mode & S_IRUSR)
    {
        dest[1] = 'r' ;
    }
    if(mode & S_IWUSR)
    {
        dest[2] = 'w' ;
    }
    if(mode & S_IXUSR)
    {
        dest[3] = 'x' ;
    }
    if(mode & S_IRGRP)
    {
        dest[4] = 'r' ;
    }
    if(mode & S_IWGRP)
    {
        dest[5] = 'w' ;
    }
    if(mode & S_IXGRP)
    {
        dest[6] = 'x' ;
    }
    if(mode & S_IROTH)
    {
        dest[7] = 'r' ;
    }
    if(mode & S_IWOTH)
    {
        dest[8] = 'w' ;
    }
    if(mode & S_IXOTH)
    {
        dest[9] = 'x' ;
    }
}

3.2 time_format

/*************************************************************************
    > File Name: time_format.c
    > Author: KrisChou
    > Mail:zhoujx0219@163.com
    > Created Time: Tue 19 Aug 2014 02:35:12 PM CST
 ************************************************************************/
#include "func.h"

char* time_format(char* src)
{
    int index = strlen(src) - 1 ;
    for(; src[index]!=':'; index -- )
    {

    }
    src[index] = '\0' ;
    return src + 4 ;
}

Makefile

SRC_DIR := ./src
INC_DIR := ./include
EXE_DIR := ./bin
OBJECTS := $(wildcard $(SRC_DIR)/*.c)
INCLUDES :=$(wildcard $(INC_DIR)/*.h)
CC := gcc
FLAGS := -o
$(EXE_DIR)/main : $(OBJECTS) $(INCLUDES)
    $(CC) $(FLAGS) $@ $(OBJECTS) -I$(INC_DIR)