实现ls及ls的改进ls的实现
ls的实现及改进ls的实现
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
ls实现代码：
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <dirent.h>
#include <string.h>
#include <linux/limits.h>
#include <pwd.h>
#include <grp.h>
#include <time.h>
#define PARAM_NONE 0 //无参数
#define PARAM_A 1 //-a
#define PARAM_L 2 //-l
#define MAXROWLEN 80 //一行最多显示的字符数
int g_leave_len = MAXROWLEN; //一行是剩余长度，用于输出对齐
int g_maxlen; //存放某目录下最长文件名的长度
void my_error(const char* errstring, int line)
{
fprintf(stderr,"line:%d",line);
perror(errstring);
exit(1);
}
//打印单个文件，且没有-l参数
void display_single(char *name)
{
int i,len;
//如果本行不足以打印一个文件名则换行
if(g_leave_len < g_maxlen)
{
printf("\n");
g_leave_len = MAXROWLEN;
}
len = strlen(name);
len = g_maxlen - len;
printf("%-s",name);
for(i=0;i<len;i++)
{
printf(" ");
}
printf(" ");
g_leave_len = g_leave_len - g_maxlen - 2;
}
/*获取文件属性并打印*/
void display_attribute(struct stat buf, char *name)
{
char buf_time[32];
struct passwd *psd;
struct group *grp;
//获取文件类型
if(S_ISLNK(buf.st_mode))
printf("1");
else if(S_ISREG(buf.st_mode))
printf("-");
else if(S_ISDIR(buf.st_mode))
printf("d");
else if(S_ISCHR(buf.st_mode))
printf("c");
else if(S_ISBLK(buf.st_mode))
printf("b");
else if(S_ISFIFO(buf.st_mode))
printf("f");
else if(S_ISSOCK(buf.st_mode))
printf("s");
//获取文件权限
if(buf.st_mode & S_IRUSR)
printf("r");
else
printf("-");
if(buf.st_mode & S_IWUSR)
printf("w");
else
printf("-");
if(buf.st_mode & S_IXUSR)
printf("x");
else
printf("-");
if(buf.st_mode & S_IRGRP)
printf("r");
else
printf("-");
if(buf.st_mode & S_IWGRP)
printf("w");
else
printf("-");
if(buf.st_mode & S_IXGRP)
printf("x");
else
printf("-");
if(buf.st_mode & S_IROTH)
printf("r");
else
printf("-");
if(buf.st_mode & S_IWOTH)
printf("w");
else
printf("-");
if(buf.st_mode & S_IXOTH)
printf("x");
else
printf("-");
printf(" ");
//根据uid和gid获取文件所有者的用户名于组名
psd = getpwuid(buf.st_uid);
grp = getgrgid(buf.st_gid);
printf("%4d",buf.st_nlink);
printf("%-8s",psd->pw_name);
printf("%-9s",grp->gr_name);
printf("%6d",buf.st_size);
strcpy(buf_time, ctime(&buf.st_mtime));//将格林位置时间转化成正常时间格式
buf_time[strlen(buf_time) - 1] = 0;
printf(" %s",buf_time);
}
//根据flag参数显示文件内容，调用display_single或者display_attribute
void display(int flag,char *pathname)
{
int i,j;
struct stat buf;
char name[NAME_MAX + 1];
for(i=0,j=0;i<strlen(pathname);i++)
{
if(pathname[i] == '/')
{
j = 0;
}
else
name[j++] = pathname[i];
}
name[j] = 0;
if(lstat(pathname,&buf) == -1)
{
my_error("stat",__LINE__);
}
if(flag == PARAM_NONE)
{
if(name[0] != '.')//不显示隐藏文件
{
display_single(name);
}
}
else if(flag == PARAM_A)
{
display_single(name);
}
else if(flag == PARAM_L)
{
if(name[0] != '.')
{
display_attribute(buf,name);
printf(" %-s\n",name);
}
}
else if(flag == (PARAM_A | PARAM_L))
{
display_attribute(buf,name);
printf(" %-s\n",name);
}
}
void display_dir(int flag_param,const char *path)
{
DIR* dir;
struct dirent* dirent;
char filenames[256][PATH_MAX+1],temp[PATH_MAX+1];
int count = 0;//总共有多少个文件
if((dir = opendir(path)) == NULL)
{
my_error("opendir",__LINE__);
}
//获取文件总数和最长文件名
while((dirent = readdir(dir)) != NULL)
{
if(g_maxlen < strlen(dirent->d_name))
g_maxlen = strlen(dirent->d_name);
count++;
}
closedir(dir);
if(count>256)
my_error("文件太多超过了256个",__LINE__);
int i,j,len = strlen(path);
//获取目录下所有的文件名
dir = opendir(path);
for(i=0;i<count;i++)
{
dirent = readdir(dir);
if(dirent == NULL)
{
my_error("readdir",__LINE__);
}
strncpy(filenames[i],path,len);
filenames[i][len] = 0;
strcat(filenames[i],dirent->d_name);
filenames[i][len+strlen(dirent->d_name)] = 0;
}
//对文件名进行排序
for(i=0;i<count-1;i++)
for(j=i+1;j<count-1;j++)
{
if(strcmp(filenames[i],filenames[j]) > 0)
{
strcpy(temp,filenames[j]);
strcpy(filenames[j] , filenames[i]);
strcpy(filenames[i] , temp);
}
}
for(i=0;i<count;i++)
display(flag_param,filenames[i]);
closedir(dir);
//没有-l的话打印一个换行符
if((flag_param & PARAM_L) == 0)
printf("\n");
}
int main(int argc, char **argv)
{
int i,j,k;
int num;//记录-的个数
char path[PATH_MAX + 1];
char param[32]; // 保存命令行参数
int flag_param = PARAM_NONE;
struct stat buf;
j = 0;
num = 0;
for(i=1;i<argc;i++)
{
if(argv[i][0] == '-')
{
for(k=1;k<strlen(argv[i]);k++)
{
param[j] = argv[i][k];
j++;
}
num++;
}
}
//现在只支持-a和-l参数
for(i=0;i<j;i++)
{
if(param[i] == 'a')
{
flag_param |= PARAM_A;
}
else if(param[i] == 'l')
{
flag_param |= PARAM_L;
}
else
{
printf("错误的参数：%c\n",param[i]);
exit(1);
}
}
param[j] = 0;
//如果没有输入文件名或者目录，就显示当前目录
if((num + 1) == argc)
{
strcpy(path,"./");
path[2] = 0;
display_dir(flag_param,path);
return 0;
}
i = 1;
for(i=1;i<argc;i++)
{
if(argv[i][0] != '-')
{
strcpy(path,argv[i]);
if(stat(path,&buf) == -1)
my_error("stat",__LINE__);
if(S_ISDIR(buf.st_mode))
{
//判断目录是否以/结尾
if(path[strlen(argv[i]) - 1] != '/')
{
path[strlen(argv[i])] = '/';
path[strlen(argv[i] + 1)] = 0;
}
else
path[strlen(argv[i])] = 0;
display_dir(flag_param,path);
}
else
{
display(flag_param,path);
}
}
}
return 0;
}
文件可执行建立
测试-l -a
参见附图，改进你的ls的实现。提交代码运行截图和码云链接。
实现代码：
#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);
}
}
}
makels改进测试：
码云链接提交图：
