/* Check that AT_SECURE=0, or that the passed name does not contain

   directories and is not overly long.  Reject empty names

   unconditionally.  */

static bool

dso_name_valid_for_suid (const char *p)

{

  if (__glibc_unlikely (__libc_enable_secure))

    {

      /* Ignore pathnames with directories for AT_SECURE=1

	 programs, and also skip overlong names.  */

      size_t len = strlen (p);

      if (len >= NAME_MAX || memchr (p, '/', len) != NULL)

	return false;

    }

  return *p != '\0';

}

/* The LD_PRELOAD environment variable gives list of libraries

   separated by white space or colons that are loaded before the

   executable's dependencies and prepended to the global scope list.

   (If the binary is running setuid all elements containing a '/' are

   ignored since it is insecure.)  Return the number of preloads

   performed.  */

unsigned int

handle_ld_preload (const char *preloadlist, struct link_map *main_map)

{

  unsigned int npreloads = 0;

  const char *p = preloadlist;

  char fname[PATH_MAX];

  while (*p != '\0')

    {

      /* Split preload list at space/colon.  */

      size_t len = strcspn (p, " :");

      if (len > 0 && len < PATH_MAX)

	{

	  memcpy (fname, p, len);

	  fname[len] = '\0';

	}

      else

	fname[0] = '\0';

      /* Skip over the substring and the following delimiter.  */

      p += len;

      if (*p == ' ' || *p == ':')

	++p;

      if (dso_name_valid_for_suid (fname))

	npreloads += do_preload (fname, main_map, "LD_PRELOAD");

    }

  return npreloads;

}