C function like `mkdir -p`

gistfile1.c

/*
 * Copyright 2011 Matthew Brush <mbrush(at)codebrainz(dot)ca>
 * Feel free to use this code however you want to.
 */
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>

int
mkdir_p (const char *pathname, 
         mode_t      mode)
{
  char  *tok              = NULL;
  char   path[PATH_MAX+1] = { 0 };
  char   tmp[PATH_MAX+1]  = { 0 };
  struct stat st          = { 0 };

  /* invalid pathname */
  if (!pathname || !pathname[0])
    return -1;

  /* pathname already exists and is a directory */
  if (stat (pathname, &st) == 0 && S_ISDIR (st.st_mode))
    return 0;

  /* doesn't need parent directories created */
  if (mkdir (pathname, mode) == 0)
    return 0;

  /* prepend initial / if needed */
  if (pathname[0] == '/')
    tmp[0] = '/';

  /* make a copy of pathname and start tokenizing it */
  strncpy (path, pathname, PATH_MAX);
  tok = strtok (path, "/");

  /* keep going until there are no tokens left */
  while (tok)
    {
      /* append the next token to the path */
      strcat (tmp, tok);

      /* create the directory and keep going unless mkdir fails and
       * errno doesn't indicate that the path already exists */
      errno = 0;
      if (mkdir (tmp, mode) != 0 && errno != EEXIST)
        return -1; /* errno still set from mkdir() call */

      /* append a / to the path for the next token and get it */
      strcat (tmp, "/");
      tok = strtok (NULL, "/");
    }

  /* success */
  return 0;
}