daima

include <stdio.h>

include <sys/types.h>

include <dirent.h>

include <sys/stat.h>

include <string.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 );

main(int ac, char av[])
{
if( ac == 1 )
do_ls( "." ); /显示当前目录/
else
while( --ac ){
printf("%s: ", ++av); /显示参数指定的目录/
do_ls( *av );
}
}

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

if( (dir_ptr = opendir( dirname )) == NULL)            /*打开目录,成功则返回 DIR 结构指针*/
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 );      /*模式到字符的转换*/

printf("%s", modestr );                           /*输出模式标识符*/

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';                 /*目录*/
if( S_ISCHR(mode) ) str[0] = 'c';                 /*字符文件*/
if( S_ISBLK(mode) ) str[0] = 'b';                 /*块文件*/

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_IXOTH)  str[7] = 'r';
if(mode & S_IXOTH)  str[8] = 'w';
if(mode & S_IXOTH)  str[9] = 'x';

}

include <pwd.h>

char *uid_to_name( uid_t uid )

/*
*返回和 uid 相应的用户名的指针
*/
{
struct passwd *getpwuid(), *pw_ptr;
static char numstr[10];

if( ( pw_ptr = getpwuid( uid ) ) == NULL ) {
    sprintf(numstr, "%d", uid);      /*没有对应的用户名则 uid 存入 numstr,返回后以字符串的形式打印 uid*/
    return numstr;
}
else
    return pw_ptr->pw_name;          /*打印用户名*/
}

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;
}