What is the correct way to use the stat() function to test if a DIRENT is a directory or a file?

Question

I'm having some trouble with the 'if(S_IFDIR(stbuf.st_mode))' line. Is this the correct way to test for a directory to recurse into? The function at the moment seems to do it right for 1 or 2 loops and then fails and segmentation faults.

I've tried the following and probably more as the condition.

S_ISDIR(st_mode)
((st_mode & ST_IFMT) == S_IFDIR)
S_IFDIR(stbuf.st_mode)

I've included the whole function because I'm concerned the problem might be elsewhere.

void getFolderContents(char *source, int temp){
struct stat stbuf;
int isDir;
dirPnt = opendir(source);
if(dirPnt != NULL){
 while(entry = readdir(dirPnt)){
  char *c = entry->d_name;
  if(strcmp(entry->d_name, cwd) == 0 || strcmp(entry->d_name, parent) == 0){
  }else{
   stat(entry->d_name, &stbuf);
   printf("%i %i ", S_IFMT, stbuf.st_mode);
   if(S_IFDIR(stbuf.st_mode)){            //Test DIR or file
    printf("DIR: %s\n", entry->d_name);
    getFolderContents(entry->d_name, 0);
   }
   printf("FILE: %s\n", entry->d_name);
  }
 }
}
closedir(dirPnt);

}

Answer 1

Yes, that's correct. But since you never change into the directory, you will not find it.

Consider the following directory hierarchy:

 a
 |
 +- b
 |  |
 |  +- c
 ...

Your code will scan its current directory, and find "a". It will determine that it is a directory, and call itself recursively, and open "a" for reading. This works. That scan will find a directory called "b", but trying to open it using the entry name only will fail, since the path is now "a/b".

I recommend changing into the directory (with chdir()) before opening it. That means you can just opendir("."). Store the old path, and chdir() out again when recursing that level is done (not before doing a recursive call to go deeper).

Answer 2

Where is entry defined ? is it a local variable ? I can't see why it would segfault, but may be you should make it a local variable. One example where it will bite you is here :

                    if(S_IFDIR(stbuf.st_mode)){            //Test DIR or file
                            printf("DIR: %s\n", entry->d_name);
                            getFolderContents(entry->d_name, 0);
                    }
                    printf("FILE: %s\n", entry->d_name);

The printf is gonna print the wrong name, so you should probably add an else here.

The same is true with dirpnt. When you go out of getFolderContents inside the while loop, you end up calling readdir on a closed dirpoint, which should get you out of the loop.

But as stated by bahbar : You can't recurse and store temporary variable in global variable