c program to list content directory with all attributes - c

Question

Current uni student and need help writing a c program that displays the contents and all information in a directory.
The listing should have the filename, mode, links, user, group size and modtime.
this is what i have completed:
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
void do_ls(char [], struct stat *);
void show_stat_info(char [], struct stat *);
main(int ac, char *av[])
{
struct stat info;
if ( ac == 1 )
do_ls( ".",&info );
else
while ( --ac ){
printf("%s:\n", *++av );
do_ls( *av,&info );
}
}
void do_ls( char dirname[], struct stat *buf )
/*
* list files in directory called dirname
*/
{
DIR *dir_ptr; /* the directory */
struct dirent *direntp; /* each entry */
if ( ( dir_ptr = opendir( dirname ) ) == NULL )
fprintf(stderr,"ls1: cannot open %s\n", dirname);
else
{
while ( ( direntp = readdir( dir_ptr ) ) != NULL )
{
printf("%s\n", direntp->d_name );
printf(" mode: %o\n", buf->st_mode); /* type + mode */
printf(" links: %d\n", buf->st_nlink); /* # links */
printf(" user: %d\n", buf->st_uid); /* user id */
printf(" group: %d\n", buf->st_gid); /* group id */
printf(" size: %d\n", buf->st_size); /* file size */
printf("modtime: %d\n", buf->st_mtime); /* modified */
//printf(" name: %s\n", fname ); /* filename */
}
closedir(dir_ptr);
}
}
right now it only lists the files inside a directory but all the details come back as zero
when I pass a directory to the function it will say "can not open filename"
This is what I am trying to achieve:
if no argument is passed through the program will print all the names and the details of the current directory
if a directory is passed through the program will print the information for all files inside the directory

Answer 1

I removed the stat pointer argument, used early return to simplify code, and called stat on each path which is build by combining the directory and file name (crudely), also fixed the format strings:
#include <dirent.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
void do_ls(char dirname[]) {
DIR *dir_ptr;
if(!(dir_ptr = opendir( dirname ))) {
fprintf(stderr,"ls1: cannot open %s\n", dirname);
return;
}
struct dirent *direntp;
while((direntp = readdir(dir_ptr))) {
struct stat buf;
char path[PATH_MAX];
snprintf(path, PATH_MAX, "%s/%s", dirname, direntp->d_name);
if(stat(path, &buf)) {
fprintf(stderr,"stat failed\n");
break;
}
printf("%s\n", direntp->d_name );
printf(" mode: %o\n", buf.st_mode); /* type + mode */
printf(" links: %ld\n", buf.st_nlink); /* # links */
printf(" user: %d\n", buf.st_uid); /* user id */
printf(" group: %d\n", buf.st_gid); /* group id */
printf(" size: %ld\n", buf.st_size); /* file size */
printf("modtime: %ld\n", buf.st_mtime); /* modified */
printf(" name: %s\n", path ); /* filename */
}
closedir(dir_ptr);
}
int main(int ac, char *av[]) {
if(ac == 1) {
do_ls(".");
return 0;
}
while(--ac) {
printf("%s:\n", *++av);
do_ls(*av);
}
return 0;
}