// MD5DEEP - dig.c
//
// By Jesse Kornblum
//
// This is a work of the US Government. In accordance with 17 USC 105,
// copyright protection is not available for any work of the US Government.
// 
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
//
// $Id: dig.c 78 2009-07-11 20:17:05Z jessekornblum $

#include "ssdeep.h"

static TCHAR DOUBLE_DIR[4] = 
  { (TCHAR)DIR_SEPARATOR, 
    (TCHAR)DIR_SEPARATOR,
    0
  };

// RBF - WTF is going on with removing double slash and Windows defines?!?

#ifndef _WIN32
static void remove_double_slash(TCHAR *fn)
{
  size_t tsize = sizeof(TCHAR);
  //  TCHAR DOUBLE_DIR[4];
  TCHAR *tmp = fn, *new;

  // RBF - Why on earth do we generate DOUBLE_DIR dynamically *every time*?
  //  _sntprintf(DOUBLE_DIR,3,_TEXT("%c%c"),DIR_SEPARATOR,DIR_SEPARATOR);

  new = _tcsstr(tmp,DOUBLE_DIR);
  while (NULL != new)
  {
#ifdef _WIN32
    /* On Windows, we have to allow the first two characters to be slashes
       to account for UNC paths. e.g. \\SERVER\dir\path  */
    if (tmp == fn)
    {  
      ++tmp;
    } 
    else
    {
#endif  // ifdef _WIN32
    
      _tmemmove(new,new+tsize,_tcslen(new));

#ifdef _WIN32
    }
#endif  // ifdef _WIN32

    new = _tcsstr(tmp,DOUBLE_DIR);

  }
}


static void remove_single_dirs(TCHAR *fn)
{
  unsigned int pos, chars_found = 0;
  size_t sz = _tcslen(fn), tsize = sizeof(TCHAR);

  for (pos = 0 ; pos < sz ; pos++)
  {
    /* Catch strings that end with /. (e.g. /foo/.)  */
    if (pos > 0 && 
	fn[pos-1] == _TEXT(DIR_SEPARATOR) && 
	fn[pos]   == _TEXT('.') &&
	fn[pos+1] == 0)
      fn[pos] = 0;
    
    if (fn[pos] == _TEXT('.') && fn[pos+1] == _TEXT(DIR_SEPARATOR))
    {
      if (chars_found && fn[pos-1] == _TEXT(DIR_SEPARATOR))
      {
	_tmemmove(fn+(pos*tsize),(fn+((pos+2)*tsize)),(sz-pos) * tsize);
	
	/* In case we have ././ we shift back one! */
	--pos;

      }
    }
    else 
      ++chars_found;
  }
}

/* Removes all "../" references from the absolute path fn */
void remove_double_dirs(TCHAR *fn)
{
  size_t pos, next_dir, sz = _tcslen(fn), tsize = sizeof(TCHAR);

  for (pos = 0; pos < _tcslen(fn) ; pos++)
  {
    if (fn[pos] == _TEXT('.') && fn[pos+1] == _TEXT('.'))
    {
      if (pos > 0)
      {

	/* We have to keep this next if statement and the one above separate.
	   If not, we can't tell later on if the pos <= 0 or
	   that the previous character was a DIR_SEPARATOR.
	   This matters when we're looking at ..foo/ as an input */
	
	if (fn[pos-1] == _TEXT(DIR_SEPARATOR))
	{
	  
	  next_dir = pos + 2;
	  
	  /* Back up to just before the previous DIR_SEPARATOR
	     unless we're already at the start of the string */
	  if (pos > 1)
	    pos -= 2;
	  else
	    pos = 0;
	  
	  while (fn[pos] != _TEXT(DIR_SEPARATOR) && pos > 0)
	    --pos;
	  
	  switch(fn[next_dir])
	  {
	  case DIR_SEPARATOR:
	    _tmemmove(fn+pos,fn+next_dir,((sz - next_dir) + 1) * tsize);
	    break;
	    
	  case 0:
	    /* If we have /.. ending the filename */
	    fn[pos+1] = 0;
	    break;
	    
	    /* If we have ..foo, we should do nothing, but skip 
	       over these double dots */
	  default:
	    pos = next_dir;
	  }
	}
      }
      
      /* If we have two dots starting off the string, we should prepend
	 a DIR_SEPARATOR and ignore the two dots. That is:
	 from the root directory the path ../foo is really just /foo */
    
      else 
      {
	fn[pos] = _TEXT(DIR_SEPARATOR);
	_tmemmove(fn+pos+1,fn+pos+3,sz-(pos+3));


      }
    }
  }
}
#endif  // ifndef _WIN32


/* On Win32 systems directories are handled... differently
   Attempting to process d: causes an error, but d:\ does not.
   Conversely, if you have a directory "foo",
   attempting to process d:\foo\ causes an error, but d:\foo does not.
   The following turns d: into d:\ and d:\foo\ into d:\foo */

#ifdef _WIN32
static void clean_name_win32(TCHAR *fn)
{
  size_t length = _tcslen(fn);

  if (length < 2)
    return;

  if (length == 2 && fn[1] == _TEXT(':'))
  {
    fn[length+1] = 0;
    fn[length]   = _TEXT(DIR_SEPARATOR);
    return;
  }

  if (fn[length-1] == _TEXT(DIR_SEPARATOR) && length != 3)
  {
    fn[length - 1] = 0;
  }
}

static int is_win32_device_file(TCHAR *fn)
{
  /* Specifications for device files came from
     http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/base/createfile.asp

     -- Physical devices (like hard drives) are 
        \\.\PhysicalDriveX where X is a digit from 0 to 9
     -- Tape devices is \\.\tapeX where X is a digit from 0 to 9
     -- Logical volumes is \\.\X: where X is a letter */

  if (!_tcsnicmp(fn, _TEXT("\\\\.\\physicaldrive"),17) &&
      (_tcslen(fn) == 18) && 
      isdigit(fn[17]))
    return TRUE;

  if (!_tcsnicmp(fn, _TEXT("\\\\.\\tape"),8) &&
      (_tcslen(fn) == 9) && 
      isdigit(fn[8]))
    return TRUE;
 
  if ((!_tcsnicmp(fn,_TEXT("\\\\.\\"),4)) &&
      (_tcslen(fn) == 6) &&
      (isalpha(fn[4])) &&
      (fn[5] == ':'))
    return TRUE;

  return FALSE;
}

#endif  /* ifdef _WIN32 */


static void clean_name(state *s, TCHAR *fn)
{
#ifdef _WIN32
  clean_name_win32(fn);
#else

  /* We don't need to call these functions when running in Windows
     as we've already called real_path() on them in main.c. These
     functions are necessary in *nix so that we can clean up the 
     path names without removing the names of symbolic links. They
     are also called when the user has specified an absolute path
     but has included extra double dots or such. */

  if (!(s->mode & mode_relative))
  {
    remove_double_slash(fn);
    remove_single_dirs(fn);
    remove_double_dirs(fn);
  }
#endif
}




static int is_special_dir(TCHAR *d)
{
  return ((!_tcsncmp(d,_TEXT("."),1) && (_tcslen(d) == 1)) ||
          (!_tcsncmp(d,_TEXT(".."),2) && (_tcslen(d) == 2)));
}

#define STATUS_OK   FALSE

static int process_dir(state *s, TCHAR *fn)
{
  int return_value = STATUS_OK;
  TCHAR *new_file;
  _TDIR *current_dir;
  struct _tdirent *entry;

  //  print_status (_TEXT("Called process_dir(%s)"), fn);

  if (have_processed_dir(fn))
  {
    print_error_unicode(s,fn,"symlink creates cycle");
    return STATUS_OK;
  }

  if (!processing_dir(fn))
    internal_error("%s: Cycle checking failed to register directory.", fn);
  
  if ((current_dir = _topendir(fn)) == NULL) 
  {
    print_error_unicode(s,fn,"%s", strerror(errno));
    return STATUS_OK;
  }    

  new_file = (TCHAR *)malloc(sizeof(TCHAR) * PATH_MAX);
  if (NULL == new_file)
    internal_error("%s: Out of memory", __progname);

  while ((entry = _treaddir(current_dir)) != NULL) 
  {
    if (is_special_dir(entry->d_name))
      continue;
    
    _sntprintf(new_file,PATH_MAX,_TEXT("%s%c%s"),
	       fn,DIR_SEPARATOR,entry->d_name);

    return_value = process_normal(s,new_file);

  }
  free(new_file);
  _tclosedir(current_dir);
  
  if (!done_processing_dir(fn))
    internal_error("%s: Cycle checking failed to unregister directory.", fn);

  return return_value;
}


static int file_type_helper(_tstat_t sb)
{
  if (S_ISREG(sb.st_mode))
    return file_regular;
  
  if (S_ISDIR(sb.st_mode))
    return file_directory;
  
  if (S_ISBLK(sb.st_mode))
    return file_block;
  
  if (S_ISCHR(sb.st_mode))
    return file_character;
  
  if (S_ISFIFO(sb.st_mode))
    return file_pipe;

  /* These file types do not exist in Win32 */
#ifndef _WIN32
  
  if (S_ISSOCK(sb.st_mode))
    return file_socket;
  
  if (S_ISLNK(sb.st_mode))
    return file_symlink;  
#endif   /* ifndef _WIN32 */


  /* Used to detect Solaris doors */
#ifdef S_IFDOOR
#ifdef S_ISDOOR
  if (S_ISDOOR(sb.st_mode))
    return file_door;
#endif
#endif

  return file_unknown;
}


static int file_type(state *s, TCHAR *fn)
{
  _tstat_t sb;

  if (NULL == s || NULL == fn)
    return file_unknown;

  if (_lstat(fn,&sb))
  {
    print_error_unicode(s,fn,"%s", strerror(errno));
    return file_unknown;
  }

  return file_type_helper(sb);
}


#ifndef _WIN32
static int should_hash_symlink(state *s, TCHAR *fn, int *link_type)
{
  int type;
  _tstat_t sb;

  if (NULL == s || NULL == fn)
    fatal_error("%s: Null state passed into should_hash_symlink", __progname);

  // We must look at what this symlink points to before we process it.
  // The normal file_type function uses lstat to examine the file,
  // we use stat to examine what this symlink points to. 
  if (_sstat(fn,&sb))
    {
      print_error_unicode(s,fn,"%s",strerror(errno));
      return FALSE;
    }

  type = file_type_helper(sb);

  if (type == file_directory)
    {
      if (s->mode & mode_recursive)
	process_dir(s,fn);
      else
	{
	  print_error_unicode(s,fn,"Is a directory");
	}
      return FALSE;
    }    

  if (link_type != NULL)
    *link_type = type;
  return TRUE;    
}
#endif


#define RETURN_IF_MODE(A) \
if (s->mode & A) \
  return TRUE; \
break;





static int should_hash(state *s, TCHAR *fn)
{
  int type = file_type(s,fn);

  if (NULL == s || NULL == fn)
    fatal_error("%s: Null state passed into should_hash", __progname);

  if (type == file_directory)
  {
    if (s->mode & mode_recursive)
      process_dir(s,fn);
    else 
    {
      print_error_unicode(s,fn,"Is a directory");
    }
    return FALSE;
  }

#ifndef _WIN32
  if (type == file_symlink)
    return should_hash_symlink(s,fn,NULL);
#endif

  if (type == file_unknown)
    return FALSE;

  /* By default we hash anything we can't identify as a "bad thing" */
  return TRUE;
}


int process_normal(state *s, TCHAR *fn)
{
  clean_name(s,fn);

  if (should_hash(s,fn))
    return (hash_file(s,fn));
  
  return FALSE;
}


#ifdef _WIN32
int process_win32(state *s, TCHAR *fn)
{
  int rc, status = STATUS_OK;
  TCHAR *asterisk, *question, *tmp, *dirname, *new_fn;
  WIN32_FIND_DATAW FindFileData;
  HANDLE hFind;

  //  print_status("Called process_win32(%S)", fn);

  if (is_win32_device_file(fn))
    return (hash_file(s,fn));

  /* Filenames without wildcards can be processed by the
     normal recursion code. */
  asterisk = _tcschr(fn,L'*');
  question = _tcschr(fn,L'?');
  if (NULL == asterisk && NULL == question)
    return (process_normal(s,fn));
  
  hFind = FindFirstFile(fn, &FindFileData);
  if (INVALID_HANDLE_VALUE == hFind)
  {
    print_error_unicode(s,fn,"No such file or directory");
    return STATUS_OK;
  }
  
#define FATAL_ERROR_UNK(A) if (NULL == A) fatal_error("%s: %s", __progname, strerror(errno));
#define FATAL_ERROR_MEM(A) if (NULL == A) fatal_error("%s: Out of memory", __progname);
  
  MD5DEEP_ALLOC(TCHAR,new_fn,PATH_MAX);
  
  dirname = _tcsdup(fn);
  FATAL_ERROR_MEM(dirname);
  
  my_dirname(dirname);
  
  rc = 1;
  while (0 != rc)
  {
    if (!(is_special_dir(FindFileData.cFileName)))
    {
      /* The filename we've found doesn't include any path information.
	 We have to add it back in manually. Thankfully Windows doesn't
	 allow wildcards in the early part of the path. For example,
	 we will never see:  c:\bin\*\tools 

	 Because the wildcard is always in the last part of the input
	 (e.g. c:\bin\*.exe) we can use the original dirname, combined
	 with the filename we've found, to make the new filename. */

      //      print_status("Found file: %S", FindFileData.cFileName);


      if (s->mode & mode_relative)
      {
	_sntprintf(new_fn,PATH_MAX,
		   _TEXT("%s%s"), dirname, FindFileData.cFileName);
      }
      else
      {	  
	MD5DEEP_ALLOC(TCHAR,tmp,PATH_MAX);
	_sntprintf(tmp,PATH_MAX,_TEXT("%s%s"),dirname,FindFileData.cFileName);
	_wfullpath(new_fn,tmp,PATH_MAX);
	free(tmp);
      }
      
      process_normal(s,new_fn); 
    }
    
    rc = FindNextFile(hFind, &FindFileData);
    if (0 == rc)
      if (ERROR_NO_MORE_FILES != GetLastError())
      {
	/* The Windows API for getting an intelligible error message
	   is beserk. Rather than play their silly games, we 
	   acknowledge that an unknown error occured and hope we
	   can continue. */
	print_error_unicode(s,fn,"Unknown error while expanding wildcard");
	free(dirname);
	free(new_fn);
	return STATUS_OK;
      }
  }
  
  rc = FindClose(hFind);
  if (0 == rc)
  {
    print_error_unicode(s,
			fn,
			"Unknown error while cleaning up wildcard expansion");
  }

  free(dirname);
  free(new_fn);

  return status;
}
#endif