20165204 第10周课下作业补做

20165204 第10周课下作业补做

一、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。

代码如下

#include        <stdio.h>
#include        <sys/types.h>
#include        <dirent.h>

void do_ls(char []);

int main(int argc, char *argv[])
{
        if ( argc == 1 )
                do_ls( "." );
        else
                while ( --argc ){
                        printf("%s:
", *++argv );
                        do_ls( *argv );
                }

        return 0;
}

void do_ls( char dirname[] )
{
        DIR             *dir_ptr;
        struct dirent   *direntp;

        if ( ( dir_ptr = opendir( dirname ) ) == NULL )
                fprintf(stderr,"ls1: cannot open %s
", dirname);
        else
        {
                while ( ( direntp = readdir( dir_ptr ) ) != NULL )
                        printf("%s
", direntp->d_name );
                closedir(dir_ptr);
        }
}

二、 实现ls -l

实现ls -l 的功能，提交测试截图和码云代码链接。
截图如下

代码如下：

#include	<stdio.h>
#include    <string.h>
#include	<sys/types.h>
#include	<dirent.h>
#include	<sys/stat.h>

void do_ls(char[]);
void dostat(char *);
void show_file_info( char *, struct stat *);
void mode_to_letters( int , char [] );
char *uid_to_name( uid_t );
char *gid_to_name( gid_t );

int main(int argc, char *argv[])
{
	if ( argc == 1 )
		do_ls( "." );
	else
		while ( --argc ){
			printf("%s:
", *++argv );
			do_ls( *argv );
		}

	return 0;
}

void do_ls( char dirname[] )
{
	DIR		*dir_ptr;		
	struct dirent	*direntp;		

	if ( ( dir_ptr = opendir( dirname ) ) == NULL )
		fprintf(stderr,"ls1: cannot open %s
", dirname);
	else
	{
		while ( ( direntp = readdir( dir_ptr ) ) != NULL )
			dostat( direntp->d_name );
		closedir(dir_ptr);
	}
}

void dostat( char *filename )
{
	struct stat info;

	if ( stat(filename, &info) == -1 )		
		perror( filename );			
	else					
		show_file_info( filename, &info );
}

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
"  , 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';
}

#include	<pwd.h>

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 ;
}

#include	<grp.h>

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;
}