How to determine files and directories in parent/o

Question

I found the answer to another question here to be very helpful.

There seems to be a limitation of the sys/stat.h library as when I tried to look in other directories everything was seen as a directory.

I was wondering if anyone knew of another system function or why it sees anything outside the current working directory as only a directory.

I appreciate any help anyone has to offer as this is perplexing me and various searches have turned up no help.

The code I made to test this is:

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

int main(void) {

        int status;

        struct stat st_buf;
        struct dirent *dirInfo;

        DIR *selDir;
        selDir = opendir("../");
                                    // ^ or wherever you want to look
        while ((dirInfo = readdir(selDir))) {

                status = stat (dirInfo->d_name, &st_buf);

                if (S_ISREG (st_buf.st_mode)) {
                        printf ("%s is a regular file.\n", dirInfo->d_name);
                }
                if (S_ISDIR (st_buf.st_mode)) {
                        printf ("%s is a directory.\n", dirInfo->d_name);
                }

        }

        return 0;

}

Answer 1

You need to check the status of the stat call; it is failing.

The trouble is that you're looking for a file the_file in the current directory when it is actually only found in ../the_file. The readdir() function gives you the name relative to the other directory, but stat() works w.r.t the current directory.

To make it work, you'd have to do the equivalent of:

char fullname[1024];

snprintf(fullname, sizeof(fullname), "%s/%s", "..", dirInfo->d_name);

if (stat(fullname, &st_buf) == 0)
    ...report on success...
else
    ...report on failure...

Answer 2

If you printed out stat, you'll notice there's an error (File not found).

This is because stat takes the path to the file, but you're just providing the file name. You then call IS_REG on garbage values.

So, suppose you have a file ../test.txt You call stat on test.txt...That isn't in directory ./test.txt, but you still print out the results from IS_REG.