xref: /haiku/src/add-ons/kernel/file_systems/ntfs/libntfs/runlist.c (revision e5d65858f2361fe0552495b61620c84dcee6bc00)
1  /**
2   * runlist.c - Run list handling code. Originated from the Linux-NTFS project.
3   *
4   * Copyright (c) 2002-2005 Anton Altaparmakov
5   * Copyright (c) 2002-2005 Richard Russon
6   * Copyright (c) 2002-2008 Szabolcs Szakacsits
7   * Copyright (c) 2004 Yura Pakhuchiy
8   * Copyright (c) 2007-2010 Jean-Pierre Andre
9   *
10   * This program/include file is free software; you can redistribute it and/or
11   * modify it under the terms of the GNU General Public License as published
12   * by the Free Software Foundation; either version 2 of the License, or
13   * (at your option) any later version.
14   *
15   * This program/include file is distributed in the hope that it will be
16   * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
17   * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18   * GNU General Public License for more details.
19   *
20   * You should have received a copy of the GNU General Public License
21   * along with this program (in the main directory of the NTFS-3G
22   * distribution in the file COPYING); if not, write to the Free Software
23   * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
24   */
25  
26  #ifdef HAVE_CONFIG_H
27  #include "config.h"
28  #endif
29  
30  #ifdef HAVE_STDIO_H
31  #include <stdio.h>
32  #endif
33  #ifdef HAVE_STRING_H
34  #include <string.h>
35  #endif
36  #ifdef HAVE_STDLIB_H
37  #include <stdlib.h>
38  #endif
39  #ifdef HAVE_ERRNO_H
40  #include <errno.h>
41  #endif
42  
43  #include "compat.h"
44  #include "types.h"
45  #include "volume.h"
46  #include "layout.h"
47  #include "debug.h"
48  #include "device.h"
49  #include "logging.h"
50  #include "misc.h"
51  
52  /**
53   * ntfs_rl_mm - runlist memmove
54   * @base:
55   * @dst:
56   * @src:
57   * @size:
58   *
59   * Description...
60   *
61   * Returns:
62   */
63  static void ntfs_rl_mm(runlist_element *base, int dst, int src, int size)
64  {
65  	if ((dst != src) && (size > 0))
66  		memmove(base + dst, base + src, size * sizeof(*base));
67  }
68  
69  /**
70   * ntfs_rl_mc - runlist memory copy
71   * @dstbase:
72   * @dst:
73   * @srcbase:
74   * @src:
75   * @size:
76   *
77   * Description...
78   *
79   * Returns:
80   */
81  static void ntfs_rl_mc(runlist_element *dstbase, int dst,
82  		       runlist_element *srcbase, int src, int size)
83  {
84  	if (size > 0)
85  		memcpy(dstbase + dst, srcbase + src, size * sizeof(*dstbase));
86  }
87  
88  /**
89   * ntfs_rl_realloc - Reallocate memory for runlists
90   * @rl:		original runlist
91   * @old_size:	number of runlist elements in the original runlist @rl
92   * @new_size:	number of runlist elements we need space for
93   *
94   * As the runlists grow, more memory will be required. To prevent large
95   * numbers of small reallocations of memory, this function returns a 4kiB block
96   * of memory.
97   *
98   * N.B.	If the new allocation doesn't require a different number of 4kiB
99   *	blocks in memory, the function will return the original pointer.
100   *
101   * On success, return a pointer to the newly allocated, or recycled, memory.
102   * On error, return NULL with errno set to the error code.
103   */
104  static runlist_element *ntfs_rl_realloc(runlist_element *rl, int old_size,
105  					int new_size)
106  {
107  	old_size = (old_size * sizeof(runlist_element) + 0xfff) & ~0xfff;
108  	new_size = (new_size * sizeof(runlist_element) + 0xfff) & ~0xfff;
109  	if (old_size == new_size)
110  		return rl;
111  	return realloc(rl, new_size);
112  }
113  
114  /*
115   *		Extend a runlist by some entry count
116   *	The runlist may have to be reallocated
117   *
118   *	Returns the reallocated runlist
119   *		or NULL if reallocation was not possible (with errno set)
120   *		the runlist is left unchanged if the reallocation fails
121   */
122  
123  runlist_element *ntfs_rl_extend(ntfs_attr *na, runlist_element *rl,
124  			int more_entries)
125  {
126  	runlist_element *newrl;
127  	int last;
128  	int irl;
129  
130  	if (na->rl && rl) {
131  		irl = (int)(rl - na->rl);
132  		last = irl;
133  		while (na->rl[last].length)
134  			last++;
135  		newrl = ntfs_rl_realloc(na->rl,last+1,last+more_entries+1);
136  		if (!newrl) {
137  			errno = ENOMEM;
138  			rl = (runlist_element*)NULL;
139  		} else {
140  			na->rl = newrl;
141  			rl = &newrl[irl];
142  		}
143  	} else {
144  		ntfs_log_error("Cannot extend unmapped runlist");
145  		errno = EIO;
146  		rl = (runlist_element*)NULL;
147  	}
148  	return (rl);
149  }
150  
151  /**
152   * ntfs_rl_are_mergeable - test if two runlists can be joined together
153   * @dst:	original runlist
154   * @src:	new runlist to test for mergeability with @dst
155   *
156   * Test if two runlists can be joined together. For this, their VCNs and LCNs
157   * must be adjacent.
158   *
159   * Return: TRUE   Success, the runlists can be merged.
160   *	   FALSE  Failure, the runlists cannot be merged.
161   */
162  static BOOL ntfs_rl_are_mergeable(runlist_element *dst, runlist_element *src)
163  {
164  	if (!dst || !src) {
165  		ntfs_log_debug("Eeek. ntfs_rl_are_mergeable() invoked with NULL "
166  				"pointer!\n");
167  		return FALSE;
168  	}
169  
170  	/* We can merge unmapped regions even if they are misaligned. */
171  	if ((dst->lcn == LCN_RL_NOT_MAPPED) && (src->lcn == LCN_RL_NOT_MAPPED))
172  		return TRUE;
173  	/* If the runs are misaligned, we cannot merge them. */
174  	if ((dst->vcn + dst->length) != src->vcn)
175  		return FALSE;
176  	/* If both runs are non-sparse and contiguous, we can merge them. */
177  	if ((dst->lcn >= 0) && (src->lcn >= 0) &&
178  		((dst->lcn + dst->length) == src->lcn))
179  		return TRUE;
180  	/* If we are merging two holes, we can merge them. */
181  	if ((dst->lcn == LCN_HOLE) && (src->lcn == LCN_HOLE))
182  		return TRUE;
183  	/* Cannot merge. */
184  	return FALSE;
185  }
186  
187  /**
188   * __ntfs_rl_merge - merge two runlists without testing if they can be merged
189   * @dst:	original, destination runlist
190   * @src:	new runlist to merge with @dst
191   *
192   * Merge the two runlists, writing into the destination runlist @dst. The
193   * caller must make sure the runlists can be merged or this will corrupt the
194   * destination runlist.
195   */
196  static void __ntfs_rl_merge(runlist_element *dst, runlist_element *src)
197  {
198  	dst->length += src->length;
199  }
200  
201  /**
202   * ntfs_rl_append - append a runlist after a given element
203   * @dst:	original runlist to be worked on
204   * @dsize:	number of elements in @dst (including end marker)
205   * @src:	runlist to be inserted into @dst
206   * @ssize:	number of elements in @src (excluding end marker)
207   * @loc:	append the new runlist @src after this element in @dst
208   *
209   * Append the runlist @src after element @loc in @dst.  Merge the right end of
210   * the new runlist, if necessary. Adjust the size of the hole before the
211   * appended runlist.
212   *
213   * On success, return a pointer to the new, combined, runlist. Note, both
214   * runlists @dst and @src are deallocated before returning so you cannot use
215   * the pointers for anything any more. (Strictly speaking the returned runlist
216   * may be the same as @dst but this is irrelevant.)
217   *
218   * On error, return NULL, with errno set to the error code. Both runlists are
219   * left unmodified.
220   */
221  static runlist_element *ntfs_rl_append(runlist_element *dst, int dsize,
222  				       runlist_element *src, int ssize, int loc)
223  {
224  	BOOL right = FALSE;	/* Right end of @src needs merging */
225  	int marker;		/* End of the inserted runs */
226  
227  	if (!dst || !src) {
228  		ntfs_log_debug("Eeek. ntfs_rl_append() invoked with NULL "
229  				"pointer!\n");
230  		errno = EINVAL;
231  		return NULL;
232  	}
233  
234  	/* First, check if the right hand end needs merging. */
235  	if ((loc + 1) < dsize)
236  		right = ntfs_rl_are_mergeable(src + ssize - 1, dst + loc + 1);
237  
238  	/* Space required: @dst size + @src size, less one if we merged. */
239  	dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - right);
240  	if (!dst)
241  		return NULL;
242  	/*
243  	 * We are guaranteed to succeed from here so can start modifying the
244  	 * original runlists.
245  	 */
246  
247  	/* First, merge the right hand end, if necessary. */
248  	if (right)
249  		__ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
250  
251  	/* marker - First run after the @src runs that have been inserted */
252  	marker = loc + ssize + 1;
253  
254  	/* Move the tail of @dst out of the way, then copy in @src. */
255  	ntfs_rl_mm(dst, marker, loc + 1 + right, dsize - loc - 1 - right);
256  	ntfs_rl_mc(dst, loc + 1, src, 0, ssize);
257  
258  	/* Adjust the size of the preceding hole. */
259  	dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
260  
261  	/* We may have changed the length of the file, so fix the end marker */
262  	if (dst[marker].lcn == LCN_ENOENT)
263  		dst[marker].vcn = dst[marker-1].vcn + dst[marker-1].length;
264  
265  	return dst;
266  }
267  
268  /**
269   * ntfs_rl_insert - insert a runlist into another
270   * @dst:	original runlist to be worked on
271   * @dsize:	number of elements in @dst (including end marker)
272   * @src:	new runlist to be inserted
273   * @ssize:	number of elements in @src (excluding end marker)
274   * @loc:	insert the new runlist @src before this element in @dst
275   *
276   * Insert the runlist @src before element @loc in the runlist @dst. Merge the
277   * left end of the new runlist, if necessary. Adjust the size of the hole
278   * after the inserted runlist.
279   *
280   * On success, return a pointer to the new, combined, runlist. Note, both
281   * runlists @dst and @src are deallocated before returning so you cannot use
282   * the pointers for anything any more. (Strictly speaking the returned runlist
283   * may be the same as @dst but this is irrelevant.)
284   *
285   * On error, return NULL, with errno set to the error code. Both runlists are
286   * left unmodified.
287   */
288  static runlist_element *ntfs_rl_insert(runlist_element *dst, int dsize,
289  				       runlist_element *src, int ssize, int loc)
290  {
291  	BOOL left = FALSE;	/* Left end of @src needs merging */
292  	BOOL disc = FALSE;	/* Discontinuity between @dst and @src */
293  	int marker;		/* End of the inserted runs */
294  
295  	if (!dst || !src) {
296  		ntfs_log_debug("Eeek. ntfs_rl_insert() invoked with NULL "
297  				"pointer!\n");
298  		errno = EINVAL;
299  		return NULL;
300  	}
301  
302  	/* disc => Discontinuity between the end of @dst and the start of @src.
303  	 *	   This means we might need to insert a "notmapped" run.
304  	 */
305  	if (loc == 0)
306  		disc = (src[0].vcn > 0);
307  	else {
308  		s64 merged_length;
309  
310  		left = ntfs_rl_are_mergeable(dst + loc - 1, src);
311  
312  		merged_length = dst[loc - 1].length;
313  		if (left)
314  			merged_length += src->length;
315  
316  		disc = (src[0].vcn > dst[loc - 1].vcn + merged_length);
317  	}
318  
319  	/* Space required: @dst size + @src size, less one if we merged, plus
320  	 * one if there was a discontinuity.
321  	 */
322  	dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc);
323  	if (!dst)
324  		return NULL;
325  	/*
326  	 * We are guaranteed to succeed from here so can start modifying the
327  	 * original runlist.
328  	 */
329  
330  	if (left)
331  		__ntfs_rl_merge(dst + loc - 1, src);
332  
333  	/*
334  	 * marker - First run after the @src runs that have been inserted
335  	 * Nominally: marker = @loc + @ssize (location + number of runs in @src)
336  	 * If "left", then the first run in @src has been merged with one in @dst.
337  	 * If "disc", then @dst and @src don't meet and we need an extra run to fill the gap.
338  	 */
339  	marker = loc + ssize - left + disc;
340  
341  	/* Move the tail of @dst out of the way, then copy in @src. */
342  	ntfs_rl_mm(dst, marker, loc, dsize - loc);
343  	ntfs_rl_mc(dst, loc + disc, src, left, ssize - left);
344  
345  	/* Adjust the VCN of the first run after the insertion ... */
346  	dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
347  	/* ... and the length. */
348  	if (dst[marker].lcn == LCN_HOLE || dst[marker].lcn == LCN_RL_NOT_MAPPED)
349  		dst[marker].length = dst[marker + 1].vcn - dst[marker].vcn;
350  
351  	/* Writing beyond the end of the file and there's a discontinuity. */
352  	if (disc) {
353  		if (loc > 0) {
354  			dst[loc].vcn = dst[loc - 1].vcn + dst[loc - 1].length;
355  			dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
356  		} else {
357  			dst[loc].vcn = 0;
358  			dst[loc].length = dst[loc + 1].vcn;
359  		}
360  		dst[loc].lcn = LCN_RL_NOT_MAPPED;
361  	}
362  	return dst;
363  }
364  
365  /**
366   * ntfs_rl_replace - overwrite a runlist element with another runlist
367   * @dst:	original runlist to be worked on
368   * @dsize:	number of elements in @dst (including end marker)
369   * @src:	new runlist to be inserted
370   * @ssize:	number of elements in @src (excluding end marker)
371   * @loc:	index in runlist @dst to overwrite with @src
372   *
373   * Replace the runlist element @dst at @loc with @src. Merge the left and
374   * right ends of the inserted runlist, if necessary.
375   *
376   * On success, return a pointer to the new, combined, runlist. Note, both
377   * runlists @dst and @src are deallocated before returning so you cannot use
378   * the pointers for anything any more. (Strictly speaking the returned runlist
379   * may be the same as @dst but this is irrelevant.)
380   *
381   * On error, return NULL, with errno set to the error code. Both runlists are
382   * left unmodified.
383   */
384  static runlist_element *ntfs_rl_replace(runlist_element *dst, int dsize,
385  					runlist_element *src, int ssize,
386  					int loc)
387  {
388  	signed delta;
389  	BOOL left  = FALSE;	/* Left end of @src needs merging */
390  	BOOL right = FALSE;	/* Right end of @src needs merging */
391  	int tail;		/* Start of tail of @dst */
392  	int marker;		/* End of the inserted runs */
393  
394  	if (!dst || !src) {
395  		ntfs_log_debug("Eeek. ntfs_rl_replace() invoked with NULL "
396  				"pointer!\n");
397  		errno = EINVAL;
398  		return NULL;
399  	}
400  
401  	/* First, see if the left and right ends need merging. */
402  	if ((loc + 1) < dsize)
403  		right = ntfs_rl_are_mergeable(src + ssize - 1, dst + loc + 1);
404  	if (loc > 0)
405  		left = ntfs_rl_are_mergeable(dst + loc - 1, src);
406  
407  	/* Allocate some space. We'll need less if the left, right, or both
408  	 * ends get merged.  The -1 accounts for the run being replaced.
409  	 */
410  	delta = ssize - 1 - left - right;
411  	if (delta > 0) {
412  		dst = ntfs_rl_realloc(dst, dsize, dsize + delta);
413  		if (!dst)
414  			return NULL;
415  	}
416  	/*
417  	 * We are guaranteed to succeed from here so can start modifying the
418  	 * original runlists.
419  	 */
420  
421  	/* First, merge the left and right ends, if necessary. */
422  	if (right)
423  		__ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
424  	if (left)
425  		__ntfs_rl_merge(dst + loc - 1, src);
426  
427  	/*
428  	 * tail - Offset of the tail of @dst
429  	 * Nominally: @tail = @loc + 1 (location, skipping the replaced run)
430  	 * If "right", then one of @dst's runs is already merged into @src.
431  	 */
432  	tail = loc + right + 1;
433  
434  	/*
435  	 * marker - First run after the @src runs that have been inserted
436  	 * Nominally: @marker = @loc + @ssize (location + number of runs in @src)
437  	 * If "left", then the first run in @src has been merged with one in @dst.
438  	 */
439  	marker = loc + ssize - left;
440  
441  	/* Move the tail of @dst out of the way, then copy in @src. */
442  	ntfs_rl_mm(dst, marker, tail, dsize - tail);
443  	ntfs_rl_mc(dst, loc, src, left, ssize - left);
444  
445  	/* We may have changed the length of the file, so fix the end marker */
446  	if (((dsize - tail) > 0) && (dst[marker].lcn == LCN_ENOENT))
447  		dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
448  
449  	return dst;
450  }
451  
452  /**
453   * ntfs_rl_split - insert a runlist into the centre of a hole
454   * @dst:	original runlist to be worked on
455   * @dsize:	number of elements in @dst (including end marker)
456   * @src:	new runlist to be inserted
457   * @ssize:	number of elements in @src (excluding end marker)
458   * @loc:	index in runlist @dst at which to split and insert @src
459   *
460   * Split the runlist @dst at @loc into two and insert @new in between the two
461   * fragments. No merging of runlists is necessary. Adjust the size of the
462   * holes either side.
463   *
464   * On success, return a pointer to the new, combined, runlist. Note, both
465   * runlists @dst and @src are deallocated before returning so you cannot use
466   * the pointers for anything any more. (Strictly speaking the returned runlist
467   * may be the same as @dst but this is irrelevant.)
468   *
469   * On error, return NULL, with errno set to the error code. Both runlists are
470   * left unmodified.
471   */
472  static runlist_element *ntfs_rl_split(runlist_element *dst, int dsize,
473  				      runlist_element *src, int ssize, int loc)
474  {
475  	if (!dst || !src) {
476  		ntfs_log_debug("Eeek. ntfs_rl_split() invoked with NULL pointer!\n");
477  		errno = EINVAL;
478  		return NULL;
479  	}
480  
481  	/* Space required: @dst size + @src size + one new hole. */
482  	dst = ntfs_rl_realloc(dst, dsize, dsize + ssize + 1);
483  	if (!dst)
484  		return dst;
485  	/*
486  	 * We are guaranteed to succeed from here so can start modifying the
487  	 * original runlists.
488  	 */
489  
490  	/* Move the tail of @dst out of the way, then copy in @src. */
491  	ntfs_rl_mm(dst, loc + 1 + ssize, loc, dsize - loc);
492  	ntfs_rl_mc(dst, loc + 1, src, 0, ssize);
493  
494  	/* Adjust the size of the holes either size of @src. */
495  	dst[loc].length		= dst[loc+1].vcn       - dst[loc].vcn;
496  	dst[loc+ssize+1].vcn	= dst[loc+ssize].vcn   + dst[loc+ssize].length;
497  	dst[loc+ssize+1].length	= dst[loc+ssize+2].vcn - dst[loc+ssize+1].vcn;
498  
499  	return dst;
500  }
501  
502  
503  /**
504   * ntfs_runlists_merge_i - see ntfs_runlists_merge
505   */
506  static runlist_element *ntfs_runlists_merge_i(runlist_element *drl,
507  					      runlist_element *srl)
508  {
509  	int di, si;		/* Current index into @[ds]rl. */
510  	int sstart;		/* First index with lcn > LCN_RL_NOT_MAPPED. */
511  	int dins;		/* Index into @drl at which to insert @srl. */
512  	int dend, send;		/* Last index into @[ds]rl. */
513  	int dfinal, sfinal;	/* The last index into @[ds]rl with
514  				   lcn >= LCN_HOLE. */
515  	int marker = 0;
516  	VCN marker_vcn = 0;
517  
518  	ntfs_log_debug("dst:\n");
519  	ntfs_debug_runlist_dump(drl);
520  	ntfs_log_debug("src:\n");
521  	ntfs_debug_runlist_dump(srl);
522  
523  	/* Check for silly calling... */
524  	if (!srl)
525  		return drl;
526  
527  	/* Check for the case where the first mapping is being done now. */
528  	if (!drl) {
529  		drl = srl;
530  		/* Complete the source runlist if necessary. */
531  		if (drl[0].vcn) {
532  			/* Scan to the end of the source runlist. */
533  			for (dend = 0; drl[dend].length; dend++)
534  				;
535  			dend++;
536  			drl = ntfs_rl_realloc(drl, dend, dend + 1);
537  			if (!drl)
538  				return drl;
539  			/* Insert start element at the front of the runlist. */
540  			ntfs_rl_mm(drl, 1, 0, dend);
541  			drl[0].vcn = 0;
542  			drl[0].lcn = LCN_RL_NOT_MAPPED;
543  			drl[0].length = drl[1].vcn;
544  		}
545  		goto finished;
546  	}
547  
548  	si = di = 0;
549  
550  	/* Skip any unmapped start element(s) in the source runlist. */
551  	while (srl[si].length && srl[si].lcn < (LCN)LCN_HOLE)
552  		si++;
553  
554  	/* Can't have an entirely unmapped source runlist. */
555  	if (!srl[si].length) {
556  		errno = EINVAL;
557  		ntfs_log_perror("%s: unmapped source runlist", __FUNCTION__);
558  		return NULL;
559  	}
560  
561  	/* Record the starting points. */
562  	sstart = si;
563  
564  	/*
565  	 * Skip forward in @drl until we reach the position where @srl needs to
566  	 * be inserted. If we reach the end of @drl, @srl just needs to be
567  	 * appended to @drl.
568  	 */
569  	for (; drl[di].length; di++) {
570  		if (drl[di].vcn + drl[di].length > srl[sstart].vcn)
571  			break;
572  	}
573  	dins = di;
574  
575  	/* Sanity check for illegal overlaps. */
576  	if ((drl[di].vcn == srl[si].vcn) && (drl[di].lcn >= 0) &&
577  			(srl[si].lcn >= 0)) {
578  		errno = ERANGE;
579  		ntfs_log_perror("Run lists overlap. Cannot merge");
580  		return NULL;
581  	}
582  
583  	/* Scan to the end of both runlists in order to know their sizes. */
584  	for (send = si; srl[send].length; send++)
585  		;
586  	for (dend = di; drl[dend].length; dend++)
587  		;
588  
589  	if (srl[send].lcn == (LCN)LCN_ENOENT)
590  		marker_vcn = srl[marker = send].vcn;
591  
592  	/* Scan to the last element with lcn >= LCN_HOLE. */
593  	for (sfinal = send; sfinal >= 0 && srl[sfinal].lcn < LCN_HOLE; sfinal--)
594  		;
595  	for (dfinal = dend; dfinal >= 0 && drl[dfinal].lcn < LCN_HOLE; dfinal--)
596  		;
597  
598  	{
599  	BOOL start;
600  	BOOL finish;
601  	int ds = dend + 1;		/* Number of elements in drl & srl */
602  	int ss = sfinal - sstart + 1;
603  
604  	start  = ((drl[dins].lcn <  LCN_RL_NOT_MAPPED) ||    /* End of file   */
605  		  (drl[dins].vcn == srl[sstart].vcn));	     /* Start of hole */
606  	finish = ((drl[dins].lcn >= LCN_RL_NOT_MAPPED) &&    /* End of file   */
607  		 ((drl[dins].vcn + drl[dins].length) <=      /* End of hole   */
608  		  (srl[send - 1].vcn + srl[send - 1].length)));
609  
610  	/* Or we'll lose an end marker */
611  	if (finish && !drl[dins].length)
612  		ss++;
613  	if (marker && (drl[dins].vcn + drl[dins].length > srl[send - 1].vcn))
614  		finish = FALSE;
615  
616  	ntfs_log_debug("dfinal = %i, dend = %i\n", dfinal, dend);
617  	ntfs_log_debug("sstart = %i, sfinal = %i, send = %i\n", sstart, sfinal, send);
618  	ntfs_log_debug("start = %i, finish = %i\n", start, finish);
619  	ntfs_log_debug("ds = %i, ss = %i, dins = %i\n", ds, ss, dins);
620  
621  	if (start) {
622  		if (finish)
623  			drl = ntfs_rl_replace(drl, ds, srl + sstart, ss, dins);
624  		else
625  			drl = ntfs_rl_insert(drl, ds, srl + sstart, ss, dins);
626  	} else {
627  		if (finish)
628  			drl = ntfs_rl_append(drl, ds, srl + sstart, ss, dins);
629  		else
630  			drl = ntfs_rl_split(drl, ds, srl + sstart, ss, dins);
631  	}
632  	if (!drl) {
633  		ntfs_log_perror("Merge failed");
634  		return drl;
635  	}
636  	free(srl);
637  	if (marker) {
638  		ntfs_log_debug("Triggering marker code.\n");
639  		for (ds = dend; drl[ds].length; ds++)
640  			;
641  		/* We only need to care if @srl ended after @drl. */
642  		if (drl[ds].vcn <= marker_vcn) {
643  			int slots = 0;
644  
645  			if (drl[ds].vcn == marker_vcn) {
646  				ntfs_log_debug("Old marker = %lli, replacing with "
647  						"LCN_ENOENT.\n",
648  						(long long)drl[ds].lcn);
649  				drl[ds].lcn = (LCN)LCN_ENOENT;
650  				goto finished;
651  			}
652  			/*
653  			 * We need to create an unmapped runlist element in
654  			 * @drl or extend an existing one before adding the
655  			 * ENOENT terminator.
656  			 */
657  			if (drl[ds].lcn == (LCN)LCN_ENOENT) {
658  				ds--;
659  				slots = 1;
660  			}
661  			if (drl[ds].lcn != (LCN)LCN_RL_NOT_MAPPED) {
662  				/* Add an unmapped runlist element. */
663  				if (!slots) {
664  					/* FIXME/TODO: We need to have the
665  					 * extra memory already! (AIA)
666  					 */
667  					drl = ntfs_rl_realloc(drl, ds, ds + 2);
668  					if (!drl)
669  						goto critical_error;
670  					slots = 2;
671  				}
672  				ds++;
673  				/* Need to set vcn if it isn't set already. */
674  				if (slots != 1)
675  					drl[ds].vcn = drl[ds - 1].vcn +
676  							drl[ds - 1].length;
677  				drl[ds].lcn = (LCN)LCN_RL_NOT_MAPPED;
678  				/* We now used up a slot. */
679  				slots--;
680  			}
681  			drl[ds].length = marker_vcn - drl[ds].vcn;
682  			/* Finally add the ENOENT terminator. */
683  			ds++;
684  			if (!slots) {
685  				/* FIXME/TODO: We need to have the extra
686  				 * memory already! (AIA)
687  				 */
688  				drl = ntfs_rl_realloc(drl, ds, ds + 1);
689  				if (!drl)
690  					goto critical_error;
691  			}
692  			drl[ds].vcn = marker_vcn;
693  			drl[ds].lcn = (LCN)LCN_ENOENT;
694  			drl[ds].length = (s64)0;
695  		}
696  	}
697  	}
698  
699  finished:
700  	/* The merge was completed successfully. */
701  	ntfs_log_debug("Merged runlist:\n");
702  	ntfs_debug_runlist_dump(drl);
703  	return drl;
704  
705  critical_error:
706  	/* Critical error! We cannot afford to fail here. */
707  	ntfs_log_perror("libntfs: Critical error");
708  	ntfs_log_debug("Forcing segmentation fault!\n");
709  	marker_vcn = ((runlist*)NULL)->lcn;
710  	return drl;
711  }
712  
713  /**
714   * ntfs_runlists_merge - merge two runlists into one
715   * @drl:	original runlist to be worked on
716   * @srl:	new runlist to be merged into @drl
717   *
718   * First we sanity check the two runlists @srl and @drl to make sure that they
719   * are sensible and can be merged. The runlist @srl must be either after the
720   * runlist @drl or completely within a hole (or unmapped region) in @drl.
721   *
722   * Merging of runlists is necessary in two cases:
723   *   1. When attribute lists are used and a further extent is being mapped.
724   *   2. When new clusters are allocated to fill a hole or extend a file.
725   *
726   * There are four possible ways @srl can be merged. It can:
727   *	- be inserted at the beginning of a hole,
728   *	- split the hole in two and be inserted between the two fragments,
729   *	- be appended at the end of a hole, or it can
730   *	- replace the whole hole.
731   * It can also be appended to the end of the runlist, which is just a variant
732   * of the insert case.
733   *
734   * On success, return a pointer to the new, combined, runlist. Note, both
735   * runlists @drl and @srl are deallocated before returning so you cannot use
736   * the pointers for anything any more. (Strictly speaking the returned runlist
737   * may be the same as @dst but this is irrelevant.)
738   *
739   * On error, return NULL, with errno set to the error code. Both runlists are
740   * left unmodified. The following error codes are defined:
741   *	ENOMEM		Not enough memory to allocate runlist array.
742   *	EINVAL		Invalid parameters were passed in.
743   *	ERANGE		The runlists overlap and cannot be merged.
744   */
745  runlist_element *ntfs_runlists_merge(runlist_element *drl,
746  		runlist_element *srl)
747  {
748  	runlist_element *rl;
749  
750  	ntfs_log_enter("Entering\n");
751  	rl = ntfs_runlists_merge_i(drl, srl);
752  	ntfs_log_leave("\n");
753  	return rl;
754  }
755  
756  /**
757   * ntfs_mapping_pairs_decompress - convert mapping pairs array to runlist
758   * @vol:	ntfs volume on which the attribute resides
759   * @attr:	attribute record whose mapping pairs array to decompress
760   * @old_rl:	optional runlist in which to insert @attr's runlist
761   *
762   * Decompress the attribute @attr's mapping pairs array into a runlist. On
763   * success, return the decompressed runlist.
764   *
765   * If @old_rl is not NULL, decompressed runlist is inserted into the
766   * appropriate place in @old_rl and the resultant, combined runlist is
767   * returned. The original @old_rl is deallocated.
768   *
769   * On error, return NULL with errno set to the error code. @old_rl is left
770   * unmodified in that case.
771   *
772   * The following error codes are defined:
773   *	ENOMEM		Not enough memory to allocate runlist array.
774   *	EIO		Corrupt runlist.
775   *	EINVAL		Invalid parameters were passed in.
776   *	ERANGE		The two runlists overlap.
777   *
778   * FIXME: For now we take the conceptionally simplest approach of creating the
779   * new runlist disregarding the already existing one and then splicing the
780   * two into one, if that is possible (we check for overlap and discard the new
781   * runlist if overlap present before returning NULL, with errno = ERANGE).
782   */
783  static runlist_element *ntfs_mapping_pairs_decompress_i(const ntfs_volume *vol,
784  		const ATTR_RECORD *attr, runlist_element *old_rl)
785  {
786  	VCN vcn;		/* Current vcn. */
787  	LCN lcn;		/* Current lcn. */
788  	s64 deltaxcn;		/* Change in [vl]cn. */
789  	runlist_element *rl;	/* The output runlist. */
790  	const u8 *buf;		/* Current position in mapping pairs array. */
791  	const u8 *attr_end;	/* End of attribute. */
792  	int err, rlsize;	/* Size of runlist buffer. */
793  	u16 rlpos;		/* Current runlist position in units of
794  				   runlist_elements. */
795  	u8 b;			/* Current byte offset in buf. */
796  
797  	ntfs_log_trace("Entering for attr 0x%x.\n",
798  			(unsigned)le32_to_cpu(attr->type));
799  	/* Make sure attr exists and is non-resident. */
800  	if (!attr || !attr->non_resident ||
801  			sle64_to_cpu(attr->lowest_vcn) < (VCN)0) {
802  		errno = EINVAL;
803  		return NULL;
804  	}
805  	/* Start at vcn = lowest_vcn and lcn 0. */
806  	vcn = sle64_to_cpu(attr->lowest_vcn);
807  	lcn = 0;
808  	/* Get start of the mapping pairs array. */
809  	buf = (const u8*)attr + le16_to_cpu(attr->mapping_pairs_offset);
810  	attr_end = (const u8*)attr + le32_to_cpu(attr->length);
811  	if (buf < (const u8*)attr || buf > attr_end) {
812  		ntfs_log_debug("Corrupt attribute.\n");
813  		errno = EIO;
814  		return NULL;
815  	}
816  	/* Current position in runlist array. */
817  	rlpos = 0;
818  	/* Allocate first 4kiB block and set current runlist size to 4kiB. */
819  	rlsize = 0x1000;
820  	rl = ntfs_malloc(rlsize);
821  	if (!rl)
822  		return NULL;
823  	/* Insert unmapped starting element if necessary. */
824  	if (vcn) {
825  		rl->vcn = (VCN)0;
826  		rl->lcn = (LCN)LCN_RL_NOT_MAPPED;
827  		rl->length = vcn;
828  		rlpos++;
829  	}
830  	while (buf < attr_end && *buf) {
831  		/*
832  		 * Allocate more memory if needed, including space for the
833  		 * not-mapped and terminator elements.
834  		 */
835  		if ((int)((rlpos + 3) * sizeof(*old_rl)) > rlsize) {
836  			runlist_element *rl2;
837  
838  			rlsize += 0x1000;
839  			rl2 = realloc(rl, rlsize);
840  			if (!rl2) {
841  				int eo = errno;
842  				free(rl);
843  				errno = eo;
844  				return NULL;
845  			}
846  			rl = rl2;
847  		}
848  		/* Enter the current vcn into the current runlist element. */
849  		rl[rlpos].vcn = vcn;
850  		/*
851  		 * Get the change in vcn, i.e. the run length in clusters.
852  		 * Doing it this way ensures that we signextend negative values.
853  		 * A negative run length doesn't make any sense, but hey, I
854  		 * didn't make up the NTFS specs and Windows NT4 treats the run
855  		 * length as a signed value so that's how it is...
856  		 */
857  		b = *buf & 0xf;
858  		if (b) {
859  			if (buf + b > attr_end)
860  				goto io_error;
861  			for (deltaxcn = (s8)buf[b--]; b; b--)
862  				deltaxcn = (deltaxcn << 8) + buf[b];
863  		} else { /* The length entry is compulsory. */
864  			ntfs_log_debug("Missing length entry in mapping pairs "
865  					"array.\n");
866  			deltaxcn = (s64)-1;
867  		}
868  		/*
869  		 * Assume a negative length to indicate data corruption and
870  		 * hence clean-up and return NULL.
871  		 */
872  		if (deltaxcn < 0) {
873  			ntfs_log_debug("Invalid length in mapping pairs array.\n");
874  			goto err_out;
875  		}
876  		/*
877  		 * Enter the current run length into the current runlist
878  		 * element.
879  		 */
880  		rl[rlpos].length = deltaxcn;
881  		/* Increment the current vcn by the current run length. */
882  		vcn += deltaxcn;
883  		/*
884  		 * There might be no lcn change at all, as is the case for
885  		 * sparse clusters on NTFS 3.0+, in which case we set the lcn
886  		 * to LCN_HOLE.
887  		 */
888  		if (!(*buf & 0xf0))
889  			rl[rlpos].lcn = (LCN)LCN_HOLE;
890  		else {
891  			/* Get the lcn change which really can be negative. */
892  			u8 b2 = *buf & 0xf;
893  			b = b2 + ((*buf >> 4) & 0xf);
894  			if (buf + b > attr_end)
895  				goto io_error;
896  			for (deltaxcn = (s8)buf[b--]; b > b2; b--)
897  				deltaxcn = (deltaxcn << 8) + buf[b];
898  			/* Change the current lcn to it's new value. */
899  			lcn += deltaxcn;
900  #ifdef DEBUG
901  			/*
902  			 * On NTFS 1.2-, apparently can have lcn == -1 to
903  			 * indicate a hole. But we haven't verified ourselves
904  			 * whether it is really the lcn or the deltaxcn that is
905  			 * -1. So if either is found give us a message so we
906  			 * can investigate it further!
907  			 */
908  			if (vol->major_ver < 3) {
909  				if (deltaxcn == (LCN)-1)
910  					ntfs_log_debug("lcn delta == -1\n");
911  				if (lcn == (LCN)-1)
912  					ntfs_log_debug("lcn == -1\n");
913  			}
914  #endif
915  			/* Check lcn is not below -1. */
916  			if (lcn < (LCN)-1) {
917  				ntfs_log_debug("Invalid LCN < -1 in mapping pairs "
918  						"array.\n");
919  				goto err_out;
920  			}
921  			/* Enter the current lcn into the runlist element. */
922  			rl[rlpos].lcn = lcn;
923  		}
924  		/* Get to the next runlist element. */
925  		rlpos++;
926  		/* Increment the buffer position to the next mapping pair. */
927  		buf += (*buf & 0xf) + ((*buf >> 4) & 0xf) + 1;
928  	}
929  	if (buf >= attr_end)
930  		goto io_error;
931  	/*
932  	 * If there is a highest_vcn specified, it must be equal to the final
933  	 * vcn in the runlist - 1, or something has gone badly wrong.
934  	 */
935  	deltaxcn = sle64_to_cpu(attr->highest_vcn);
936  	if (deltaxcn && vcn - 1 != deltaxcn) {
937  mpa_err:
938  		ntfs_log_debug("Corrupt mapping pairs array in non-resident "
939  				"attribute.\n");
940  		goto err_out;
941  	}
942  	/* Setup not mapped runlist element if this is the base extent. */
943  	if (!attr->lowest_vcn) {
944  		VCN max_cluster;
945  
946  		max_cluster = ((sle64_to_cpu(attr->allocated_size) +
947  				vol->cluster_size - 1) >>
948  				vol->cluster_size_bits) - 1;
949  		/*
950  		 * A highest_vcn of zero means this is a single extent
951  		 * attribute so simply terminate the runlist with LCN_ENOENT).
952  		 */
953  		if (deltaxcn) {
954  			/*
955  			 * If there is a difference between the highest_vcn and
956  			 * the highest cluster, the runlist is either corrupt
957  			 * or, more likely, there are more extents following
958  			 * this one.
959  			 */
960  			if (deltaxcn < max_cluster) {
961  				ntfs_log_debug("More extents to follow; deltaxcn = "
962  						"0x%llx, max_cluster = 0x%llx\n",
963  						(long long)deltaxcn,
964  						(long long)max_cluster);
965  				rl[rlpos].vcn = vcn;
966  				vcn += rl[rlpos].length = max_cluster - deltaxcn;
967  				rl[rlpos].lcn = (LCN)LCN_RL_NOT_MAPPED;
968  				rlpos++;
969  			} else if (deltaxcn > max_cluster) {
970  				ntfs_log_debug("Corrupt attribute. deltaxcn = "
971  						"0x%llx, max_cluster = 0x%llx\n",
972  						(long long)deltaxcn,
973  						(long long)max_cluster);
974  				goto mpa_err;
975  			}
976  		}
977  		rl[rlpos].lcn = (LCN)LCN_ENOENT;
978  	} else /* Not the base extent. There may be more extents to follow. */
979  		rl[rlpos].lcn = (LCN)LCN_RL_NOT_MAPPED;
980  
981  	/* Setup terminating runlist element. */
982  	rl[rlpos].vcn = vcn;
983  	rl[rlpos].length = (s64)0;
984  	/* If no existing runlist was specified, we are done. */
985  	if (!old_rl) {
986  		ntfs_log_debug("Mapping pairs array successfully decompressed:\n");
987  		ntfs_debug_runlist_dump(rl);
988  		return rl;
989  	}
990  	/* Now combine the new and old runlists checking for overlaps. */
991  	old_rl = ntfs_runlists_merge(old_rl, rl);
992  	if (old_rl)
993  		return old_rl;
994  	err = errno;
995  	free(rl);
996  	ntfs_log_debug("Failed to merge runlists.\n");
997  	errno = err;
998  	return NULL;
999  io_error:
1000  	ntfs_log_debug("Corrupt attribute.\n");
1001  err_out:
1002  	free(rl);
1003  	errno = EIO;
1004  	return NULL;
1005  }
1006  
1007  runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
1008  		const ATTR_RECORD *attr, runlist_element *old_rl)
1009  {
1010  	runlist_element *rle;
1011  
1012  	ntfs_log_enter("Entering\n");
1013  	rle = ntfs_mapping_pairs_decompress_i(vol, attr, old_rl);
1014  	ntfs_log_leave("\n");
1015  	return rle;
1016  }
1017  
1018  /**
1019   * ntfs_rl_vcn_to_lcn - convert a vcn into a lcn given a runlist
1020   * @rl:		runlist to use for conversion
1021   * @vcn:	vcn to convert
1022   *
1023   * Convert the virtual cluster number @vcn of an attribute into a logical
1024   * cluster number (lcn) of a device using the runlist @rl to map vcns to their
1025   * corresponding lcns.
1026   *
1027   * Since lcns must be >= 0, we use negative return values with special meaning:
1028   *
1029   * Return value			Meaning / Description
1030   * ==================================================
1031   *  -1 = LCN_HOLE		Hole / not allocated on disk.
1032   *  -2 = LCN_RL_NOT_MAPPED	This is part of the runlist which has not been
1033   *				inserted into the runlist yet.
1034   *  -3 = LCN_ENOENT		There is no such vcn in the attribute.
1035   *  -4 = LCN_EINVAL		Input parameter error.
1036   */
1037  LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn)
1038  {
1039  	int i;
1040  
1041  	if (vcn < (VCN)0)
1042  		return (LCN)LCN_EINVAL;
1043  	/*
1044  	 * If rl is NULL, assume that we have found an unmapped runlist. The
1045  	 * caller can then attempt to map it and fail appropriately if
1046  	 * necessary.
1047  	 */
1048  	if (!rl)
1049  		return (LCN)LCN_RL_NOT_MAPPED;
1050  
1051  	/* Catch out of lower bounds vcn. */
1052  	if (vcn < rl[0].vcn)
1053  		return (LCN)LCN_ENOENT;
1054  
1055  	for (i = 0; rl[i].length; i++) {
1056  		if (vcn < rl[i+1].vcn) {
1057  			if (rl[i].lcn >= (LCN)0)
1058  				return rl[i].lcn + (vcn - rl[i].vcn);
1059  			return rl[i].lcn;
1060  		}
1061  	}
1062  	/*
1063  	 * The terminator element is setup to the correct value, i.e. one of
1064  	 * LCN_HOLE, LCN_RL_NOT_MAPPED, or LCN_ENOENT.
1065  	 */
1066  	if (rl[i].lcn < (LCN)0)
1067  		return rl[i].lcn;
1068  	/* Just in case... We could replace this with BUG() some day. */
1069  	return (LCN)LCN_ENOENT;
1070  }
1071  
1072  /**
1073   * ntfs_rl_pread - gather read from disk
1074   * @vol:	ntfs volume to read from
1075   * @rl:		runlist specifying where to read the data from
1076   * @pos:	byte position within runlist @rl at which to begin the read
1077   * @count:	number of bytes to read
1078   * @b:		data buffer into which to read from disk
1079   *
1080   * This function will read @count bytes from the volume @vol to the data buffer
1081   * @b gathering the data as specified by the runlist @rl. The read begins at
1082   * offset @pos into the runlist @rl.
1083   *
1084   * On success, return the number of successfully read bytes. If this number is
1085   * lower than @count this means that the read reached end of file or that an
1086   * error was encountered during the read so that the read is partial. 0 means
1087   * nothing was read (also return 0 when @count is 0).
1088   *
1089   * On error and nothing has been read, return -1 with errno set appropriately
1090   * to the return code of ntfs_pread(), or to EINVAL in case of invalid
1091   * arguments.
1092   *
1093   * NOTE: If we encounter EOF while reading we return EIO because we assume that
1094   * the run list must point to valid locations within the ntfs volume.
1095   */
1096  s64 ntfs_rl_pread(const ntfs_volume *vol, const runlist_element *rl,
1097  		const s64 pos, s64 count, void *b)
1098  {
1099  	s64 bytes_read, to_read, ofs, total;
1100  	int err = EIO;
1101  
1102  	if (!vol || !rl || pos < 0 || count < 0) {
1103  		errno = EINVAL;
1104  		ntfs_log_perror("Failed to read runlist [vol: %p rl: %p "
1105  				"pos: %lld count: %lld]", vol, rl,
1106  				(long long)pos, (long long)count);
1107  		return -1;
1108  	}
1109  	if (!count)
1110  		return count;
1111  	/* Seek in @rl to the run containing @pos. */
1112  	for (ofs = 0; rl->length && (ofs + (rl->length <<
1113  			vol->cluster_size_bits) <= pos); rl++)
1114  		ofs += (rl->length << vol->cluster_size_bits);
1115  	/* Offset in the run at which to begin reading. */
1116  	ofs = pos - ofs;
1117  	for (total = 0LL; count; rl++, ofs = 0) {
1118  		if (!rl->length)
1119  			goto rl_err_out;
1120  		if (rl->lcn < (LCN)0) {
1121  			if (rl->lcn != (LCN)LCN_HOLE)
1122  				goto rl_err_out;
1123  			/* It is a hole. Just fill buffer @b with zeroes. */
1124  			to_read = min(count, (rl->length <<
1125  					vol->cluster_size_bits) - ofs);
1126  			memset(b, 0, to_read);
1127  			/* Update counters and proceed with next run. */
1128  			total += to_read;
1129  			count -= to_read;
1130  			b = (u8*)b + to_read;
1131  			continue;
1132  		}
1133  		/* It is a real lcn, read it from the volume. */
1134  		to_read = min(count, (rl->length << vol->cluster_size_bits) -
1135  				ofs);
1136  retry:
1137  		bytes_read = ntfs_pread(vol->dev, (rl->lcn <<
1138  				vol->cluster_size_bits) + ofs, to_read, b);
1139  		/* If everything ok, update progress counters and continue. */
1140  		if (bytes_read > 0) {
1141  			total += bytes_read;
1142  			count -= bytes_read;
1143  			b = (u8*)b + bytes_read;
1144  			continue;
1145  		}
1146  		/* If the syscall was interrupted, try again. */
1147  		if (bytes_read == (s64)-1 && errno == EINTR)
1148  			goto retry;
1149  		if (bytes_read == (s64)-1)
1150  			err = errno;
1151  		goto rl_err_out;
1152  	}
1153  	/* Finally, return the number of bytes read. */
1154  	return total;
1155  rl_err_out:
1156  	if (total)
1157  		return total;
1158  	errno = err;
1159  	return -1;
1160  }
1161  
1162  /**
1163   * ntfs_rl_pwrite - scatter write to disk
1164   * @vol:	ntfs volume to write to
1165   * @rl:		runlist entry specifying where to write the data to
1166   * @ofs:	offset in file for runlist element indicated in @rl
1167   * @pos:	byte position from runlist beginning at which to begin the write
1168   * @count:	number of bytes to write
1169   * @b:		data buffer to write to disk
1170   *
1171   * This function will write @count bytes from data buffer @b to the volume @vol
1172   * scattering the data as specified by the runlist @rl. The write begins at
1173   * offset @pos into the runlist @rl. If a run is sparse then the related buffer
1174   * data is ignored which means that the caller must ensure they are consistent.
1175   *
1176   * On success, return the number of successfully written bytes. If this number
1177   * is lower than @count this means that the write has been interrupted in
1178   * flight or that an error was encountered during the write so that the write
1179   * is partial. 0 means nothing was written (also return 0 when @count is 0).
1180   *
1181   * On error and nothing has been written, return -1 with errno set
1182   * appropriately to the return code of ntfs_pwrite(), or to to EINVAL in case
1183   * of invalid arguments.
1184   */
1185  s64 ntfs_rl_pwrite(const ntfs_volume *vol, const runlist_element *rl,
1186  		s64 ofs, const s64 pos, s64 count, void *b)
1187  {
1188  	s64 written, to_write, total = 0;
1189  	int err = EIO;
1190  
1191  	if (!vol || !rl || pos < 0 || count < 0) {
1192  		errno = EINVAL;
1193  		ntfs_log_perror("Failed to write runlist [vol: %p rl: %p "
1194  				"pos: %lld count: %lld]", vol, rl,
1195  				(long long)pos, (long long)count);
1196  		goto errno_set;
1197  	}
1198  	if (!count)
1199  		goto out;
1200  	/* Seek in @rl to the run containing @pos. */
1201  	while (rl->length && (ofs + (rl->length <<
1202  			vol->cluster_size_bits) <= pos)) {
1203  		ofs += (rl->length << vol->cluster_size_bits);
1204  		rl++;
1205  	}
1206  	/* Offset in the run at which to begin writing. */
1207  	ofs = pos - ofs;
1208  	for (total = 0LL; count; rl++, ofs = 0) {
1209  		if (!rl->length)
1210  			goto rl_err_out;
1211  		if (rl->lcn < (LCN)0) {
1212  
1213  			if (rl->lcn != (LCN)LCN_HOLE)
1214  				goto rl_err_out;
1215  
1216  			to_write = min(count, (rl->length <<
1217  					       vol->cluster_size_bits) - ofs);
1218  
1219  			total += to_write;
1220  			count -= to_write;
1221  			b = (u8*)b + to_write;
1222  			continue;
1223  		}
1224  		/* It is a real lcn, write it to the volume. */
1225  		to_write = min(count, (rl->length << vol->cluster_size_bits) -
1226  				ofs);
1227  retry:
1228  		if (!NVolReadOnly(vol))
1229  			written = ntfs_pwrite(vol->dev, (rl->lcn <<
1230  					vol->cluster_size_bits) + ofs,
1231  					to_write, b);
1232  		else
1233  			written = to_write;
1234  		/* If everything ok, update progress counters and continue. */
1235  		if (written > 0) {
1236  			total += written;
1237  			count -= written;
1238  			b = (u8*)b + written;
1239  			continue;
1240  		}
1241  		/* If the syscall was interrupted, try again. */
1242  		if (written == (s64)-1 && errno == EINTR)
1243  			goto retry;
1244  		if (written == (s64)-1)
1245  			err = errno;
1246  		goto rl_err_out;
1247  	}
1248  out:
1249  	return total;
1250  rl_err_out:
1251  	if (total)
1252  		goto out;
1253  	errno = err;
1254  errno_set:
1255  	total = -1;
1256  	goto out;
1257  }
1258  
1259  /**
1260   * ntfs_get_nr_significant_bytes - get number of bytes needed to store a number
1261   * @n:		number for which to get the number of bytes for
1262   *
1263   * Return the number of bytes required to store @n unambiguously as
1264   * a signed number.
1265   *
1266   * This is used in the context of the mapping pairs array to determine how
1267   * many bytes will be needed in the array to store a given logical cluster
1268   * number (lcn) or a specific run length.
1269   *
1270   * Return the number of bytes written. This function cannot fail.
1271   */
1272  int ntfs_get_nr_significant_bytes(const s64 n)
1273  {
1274  	u64 l;
1275  	int i;
1276  
1277  	l = (n < 0 ? ~n : n);
1278  	i = 1;
1279  	if (l >= 128) {
1280  		l >>= 7;
1281  		do {
1282  			i++;
1283  			l >>= 8;
1284  		} while (l);
1285  	}
1286  	return i;
1287  }
1288  
1289  /**
1290   * ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array
1291   * @vol:	ntfs volume (needed for the ntfs version)
1292   * @rl:		runlist for which to determine the size of the mapping pairs
1293   * @start_vcn:	vcn at which to start the mapping pairs array
1294   *
1295   * Walk the runlist @rl and calculate the size in bytes of the mapping pairs
1296   * array corresponding to the runlist @rl, starting at vcn @start_vcn.  This
1297   * for example allows us to allocate a buffer of the right size when building
1298   * the mapping pairs array.
1299   *
1300   * If @rl is NULL, just return 1 (for the single terminator byte).
1301   *
1302   * Return the calculated size in bytes on success.  On error, return -1 with
1303   * errno set to the error code.  The following error codes are defined:
1304   *	EINVAL	- Run list contains unmapped elements. Make sure to only pass
1305   *		  fully mapped runlists to this function.
1306   *		- @start_vcn is invalid.
1307   *	EIO	- The runlist is corrupt.
1308   */
1309  int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
1310  		const runlist_element *rl, const VCN start_vcn, int max_size)
1311  {
1312  	LCN prev_lcn;
1313  	int rls;
1314  
1315  	if (start_vcn < 0) {
1316  		ntfs_log_trace("start_vcn %lld (should be >= 0)\n",
1317  				(long long) start_vcn);
1318  		errno = EINVAL;
1319  		goto errno_set;
1320  	}
1321  	if (!rl) {
1322  		if (start_vcn) {
1323  			ntfs_log_trace("rl NULL, start_vcn %lld (should be > 0)\n",
1324  					(long long) start_vcn);
1325  			errno = EINVAL;
1326  			goto errno_set;
1327  		}
1328  		rls = 1;
1329  		goto out;
1330  	}
1331  	/* Skip to runlist element containing @start_vcn. */
1332  	while (rl->length && start_vcn >= rl[1].vcn)
1333  		rl++;
1334  	if ((!rl->length && start_vcn > rl->vcn) || start_vcn < rl->vcn) {
1335  		errno = EINVAL;
1336  		goto errno_set;
1337  	}
1338  	prev_lcn = 0;
1339  	/* Always need the terminating zero byte. */
1340  	rls = 1;
1341  	/* Do the first partial run if present. */
1342  	if (start_vcn > rl->vcn) {
1343  		s64 delta;
1344  
1345  		/* We know rl->length != 0 already. */
1346  		if (rl->length < 0 || rl->lcn < LCN_HOLE)
1347  			goto err_out;
1348  		delta = start_vcn - rl->vcn;
1349  		/* Header byte + length. */
1350  		rls += 1 + ntfs_get_nr_significant_bytes(rl->length - delta);
1351  		/*
1352  		 * If the logical cluster number (lcn) denotes a hole and we
1353  		 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1354  		 * zero space. On earlier NTFS versions we just store the lcn.
1355  		 * Note: this assumes that on NTFS 1.2-, holes are stored with
1356  		 * an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
1357  		 */
1358  		if (rl->lcn >= 0 || vol->major_ver < 3) {
1359  			prev_lcn = rl->lcn;
1360  			if (rl->lcn >= 0)
1361  				prev_lcn += delta;
1362  			/* Change in lcn. */
1363  			rls += ntfs_get_nr_significant_bytes(prev_lcn);
1364  		}
1365  		/* Go to next runlist element. */
1366  		rl++;
1367  	}
1368  	/* Do the full runs. */
1369  	for (; rl->length && (rls <= max_size); rl++) {
1370  		if (rl->length < 0 || rl->lcn < LCN_HOLE)
1371  			goto err_out;
1372  		/* Header byte + length. */
1373  		rls += 1 + ntfs_get_nr_significant_bytes(rl->length);
1374  		/*
1375  		 * If the logical cluster number (lcn) denotes a hole and we
1376  		 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1377  		 * zero space. On earlier NTFS versions we just store the lcn.
1378  		 * Note: this assumes that on NTFS 1.2-, holes are stored with
1379  		 * an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
1380  		 */
1381  		if (rl->lcn >= 0 || vol->major_ver < 3) {
1382  			/* Change in lcn. */
1383  			rls += ntfs_get_nr_significant_bytes(rl->lcn -
1384  					prev_lcn);
1385  			prev_lcn = rl->lcn;
1386  		}
1387  	}
1388  out:
1389  	return rls;
1390  err_out:
1391  	if (rl->lcn == LCN_RL_NOT_MAPPED)
1392  		errno = EINVAL;
1393  	else
1394  		errno = EIO;
1395  errno_set:
1396  	rls = -1;
1397  	goto out;
1398  }
1399  
1400  /**
1401   * ntfs_write_significant_bytes - write the significant bytes of a number
1402   * @dst:	destination buffer to write to
1403   * @dst_max:	pointer to last byte of destination buffer for bounds checking
1404   * @n:		number whose significant bytes to write
1405   *
1406   * Store in @dst, the minimum bytes of the number @n which are required to
1407   * identify @n unambiguously as a signed number, taking care not to exceed
1408   * @dest_max, the maximum position within @dst to which we are allowed to
1409   * write.
1410   *
1411   * This is used when building the mapping pairs array of a runlist to compress
1412   * a given logical cluster number (lcn) or a specific run length to the minimum
1413   * size possible.
1414   *
1415   * Return the number of bytes written on success. On error, i.e. the
1416   * destination buffer @dst is too small, return -1 with errno set ENOSPC.
1417   */
1418  int ntfs_write_significant_bytes(u8 *dst, const u8 *dst_max, const s64 n)
1419  {
1420  	s64 l = n;
1421  	int i;
1422  
1423  	i = 0;
1424  	if (dst > dst_max)
1425  		goto err_out;
1426  	*dst++ = l;
1427  	i++;
1428  	while ((l > 0x7f) || (l < -0x80)) {
1429  		if (dst > dst_max)
1430  			goto err_out;
1431  		l >>= 8;
1432  		*dst++ = l;
1433  		i++;
1434  	}
1435  	return i;
1436  err_out:
1437  	errno = ENOSPC;
1438  	return -1;
1439  }
1440  
1441  /**
1442   * ntfs_mapping_pairs_build - build the mapping pairs array from a runlist
1443   * @vol:	ntfs volume (needed for the ntfs version)
1444   * @dst:	destination buffer to which to write the mapping pairs array
1445   * @dst_len:	size of destination buffer @dst in bytes
1446   * @rl:		runlist for which to build the mapping pairs array
1447   * @start_vcn:	vcn at which to start the mapping pairs array
1448   * @stop_vcn:	first vcn outside destination buffer on success or ENOSPC error
1449   *
1450   * Create the mapping pairs array from the runlist @rl, starting at vcn
1451   * @start_vcn and save the array in @dst.  @dst_len is the size of @dst in
1452   * bytes and it should be at least equal to the value obtained by calling
1453   * ntfs_get_size_for_mapping_pairs().
1454   *
1455   * If @rl is NULL, just write a single terminator byte to @dst.
1456   *
1457   * On success or ENOSPC error, if @stop_vcn is not NULL, *@stop_vcn is set to
1458   * the first vcn outside the destination buffer. Note that on error @dst has
1459   * been filled with all the mapping pairs that will fit, thus it can be treated
1460   * as partial success, in that a new attribute extent needs to be created or the
1461   * next extent has to be used and the mapping pairs build has to be continued
1462   * with @start_vcn set to *@stop_vcn.
1463   *
1464   * Return 0 on success.  On error, return -1 with errno set to the error code.
1465   * The following error codes are defined:
1466   *	EINVAL	- Run list contains unmapped elements. Make sure to only pass
1467   *		  fully mapped runlists to this function.
1468   *		- @start_vcn is invalid.
1469   *	EIO	- The runlist is corrupt.
1470   *	ENOSPC	- The destination buffer is too small.
1471   */
1472  int ntfs_mapping_pairs_build(const ntfs_volume *vol, u8 *dst,
1473  		const int dst_len, const runlist_element *rl,
1474  		const VCN start_vcn, runlist_element const **stop_rl)
1475  {
1476  	LCN prev_lcn;
1477  	u8 *dst_max, *dst_next;
1478  	s8 len_len, lcn_len;
1479  	int ret = 0;
1480  
1481  	if (start_vcn < 0)
1482  		goto val_err;
1483  	if (!rl) {
1484  		if (start_vcn)
1485  			goto val_err;
1486  		if (stop_rl)
1487  			*stop_rl = rl;
1488  		if (dst_len < 1)
1489  			goto nospc_err;
1490  		goto ok;
1491  	}
1492  	/* Skip to runlist element containing @start_vcn. */
1493  	while (rl->length && start_vcn >= rl[1].vcn)
1494  		rl++;
1495  	if ((!rl->length && start_vcn > rl->vcn) || start_vcn < rl->vcn)
1496  		goto val_err;
1497  	/*
1498  	 * @dst_max is used for bounds checking in
1499  	 * ntfs_write_significant_bytes().
1500  	 */
1501  	dst_max = dst + dst_len - 1;
1502  	prev_lcn = 0;
1503  	/* Do the first partial run if present. */
1504  	if (start_vcn > rl->vcn) {
1505  		s64 delta;
1506  
1507  		/* We know rl->length != 0 already. */
1508  		if (rl->length < 0 || rl->lcn < LCN_HOLE)
1509  			goto err_out;
1510  		delta = start_vcn - rl->vcn;
1511  		/* Write length. */
1512  		len_len = ntfs_write_significant_bytes(dst + 1, dst_max,
1513  				rl->length - delta);
1514  		if (len_len < 0)
1515  			goto size_err;
1516  		/*
1517  		 * If the logical cluster number (lcn) denotes a hole and we
1518  		 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1519  		 * zero space. On earlier NTFS versions we just write the lcn
1520  		 * change.  FIXME: Do we need to write the lcn change or just
1521  		 * the lcn in that case?  Not sure as I have never seen this
1522  		 * case on NT4. - We assume that we just need to write the lcn
1523  		 * change until someone tells us otherwise... (AIA)
1524  		 */
1525  		if (rl->lcn >= 0 || vol->major_ver < 3) {
1526  			prev_lcn = rl->lcn;
1527  			if (rl->lcn >= 0)
1528  				prev_lcn += delta;
1529  			/* Write change in lcn. */
1530  			lcn_len = ntfs_write_significant_bytes(dst + 1 +
1531  					len_len, dst_max, prev_lcn);
1532  			if (lcn_len < 0)
1533  				goto size_err;
1534  		} else
1535  			lcn_len = 0;
1536  		dst_next = dst + len_len + lcn_len + 1;
1537  		if (dst_next > dst_max)
1538  			goto size_err;
1539  		/* Update header byte. */
1540  		*dst = lcn_len << 4 | len_len;
1541  		/* Position at next mapping pairs array element. */
1542  		dst = dst_next;
1543  		/* Go to next runlist element. */
1544  		rl++;
1545  	}
1546  	/* Do the full runs. */
1547  	for (; rl->length; rl++) {
1548  		if (rl->length < 0 || rl->lcn < LCN_HOLE)
1549  			goto err_out;
1550  		/* Write length. */
1551  		len_len = ntfs_write_significant_bytes(dst + 1, dst_max,
1552  				rl->length);
1553  		if (len_len < 0)
1554  			goto size_err;
1555  		/*
1556  		 * If the logical cluster number (lcn) denotes a hole and we
1557  		 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1558  		 * zero space. On earlier NTFS versions we just write the lcn
1559  		 * change. FIXME: Do we need to write the lcn change or just
1560  		 * the lcn in that case? Not sure as I have never seen this
1561  		 * case on NT4. - We assume that we just need to write the lcn
1562  		 * change until someone tells us otherwise... (AIA)
1563  		 */
1564  		if (rl->lcn >= 0 || vol->major_ver < 3) {
1565  			/* Write change in lcn. */
1566  			lcn_len = ntfs_write_significant_bytes(dst + 1 +
1567  					len_len, dst_max, rl->lcn - prev_lcn);
1568  			if (lcn_len < 0)
1569  				goto size_err;
1570  			prev_lcn = rl->lcn;
1571  		} else
1572  			lcn_len = 0;
1573  		dst_next = dst + len_len + lcn_len + 1;
1574  		if (dst_next > dst_max)
1575  			goto size_err;
1576  		/* Update header byte. */
1577  		*dst = lcn_len << 4 | len_len;
1578  		/* Position at next mapping pairs array element. */
1579  		dst += 1 + len_len + lcn_len;
1580  	}
1581  	/* Set stop vcn. */
1582  	if (stop_rl)
1583  		*stop_rl = rl;
1584  ok:
1585  	/* Add terminator byte. */
1586  	*dst = 0;
1587  out:
1588  	return ret;
1589  size_err:
1590  	/* Set stop vcn. */
1591  	if (stop_rl)
1592  		*stop_rl = rl;
1593  	/* Add terminator byte. */
1594  	*dst = 0;
1595  nospc_err:
1596  	errno = ENOSPC;
1597  	goto errno_set;
1598  val_err:
1599  	errno = EINVAL;
1600  	goto errno_set;
1601  err_out:
1602  	if (rl->lcn == LCN_RL_NOT_MAPPED)
1603  		errno = EINVAL;
1604  	else
1605  		errno = EIO;
1606  errno_set:
1607  	ret = -1;
1608  	goto out;
1609  }
1610  
1611  /**
1612   * ntfs_rl_truncate - truncate a runlist starting at a specified vcn
1613   * @arl:	address of runlist to truncate
1614   * @start_vcn:	first vcn which should be cut off
1615   *
1616   * Truncate the runlist *@arl starting at vcn @start_vcn as well as the memory
1617   * buffer holding the runlist.
1618   *
1619   * Return 0 on success and -1 on error with errno set to the error code.
1620   *
1621   * NOTE: @arl is the address of the runlist. We need the address so we can
1622   * modify the pointer to the runlist with the new, reallocated memory buffer.
1623   */
1624  int ntfs_rl_truncate(runlist **arl, const VCN start_vcn)
1625  {
1626  	runlist *rl;
1627  	/* BOOL is_end = FALSE; */
1628  
1629  	if (!arl || !*arl) {
1630  		errno = EINVAL;
1631  		if (!arl)
1632  			ntfs_log_perror("rl_truncate error: arl: %p", arl);
1633  		else
1634  			ntfs_log_perror("rl_truncate error:"
1635  				" arl: %p *arl: %p", arl, *arl);
1636  		return -1;
1637  	}
1638  
1639  	rl = *arl;
1640  
1641  	if (start_vcn < rl->vcn) {
1642  		errno = EINVAL;
1643  		ntfs_log_perror("Start_vcn lies outside front of runlist");
1644  		return -1;
1645  	}
1646  
1647  	/* Find the starting vcn in the run list. */
1648  	while (rl->length) {
1649  		if (start_vcn < rl[1].vcn)
1650  			break;
1651  		rl++;
1652  	}
1653  
1654  	if (!rl->length) {
1655  		errno = EIO;
1656  		ntfs_log_trace("Truncating already truncated runlist?\n");
1657  		return -1;
1658  	}
1659  
1660  	/* Truncate the run. */
1661  	rl->length = start_vcn - rl->vcn;
1662  
1663  	/*
1664  	 * If a run was partially truncated, make the following runlist
1665  	 * element a terminator instead of the truncated runlist
1666  	 * element itself.
1667  	 */
1668  	if (rl->length) {
1669  		++rl;
1670  /*
1671  		if (!rl->length)
1672  			is_end = TRUE;
1673  */
1674  		rl->vcn = start_vcn;
1675  		rl->length = 0;
1676  	}
1677  	rl->lcn = (LCN)LCN_ENOENT;
1678  	/**
1679  	 * Reallocate memory if necessary.
1680  	 * FIXME: Below code is broken, because runlist allocations must be
1681  	 * a multiple of 4096. The code caused crashes and corruptions.
1682  	 */
1683  /*
1684  	 if (!is_end) {
1685  		size_t new_size = (rl - *arl + 1) * sizeof(runlist_element);
1686  		rl = realloc(*arl, new_size);
1687  		if (rl)
1688  			*arl = rl;
1689  	}
1690  */
1691  	return 0;
1692  }
1693  
1694  /**
1695   * ntfs_rl_sparse - check whether runlist have sparse regions or not.
1696   * @rl:		runlist to check
1697   *
1698   * Return 1 if have, 0 if not, -1 on error with errno set to the error code.
1699   */
1700  int ntfs_rl_sparse(runlist *rl)
1701  {
1702  	runlist *rlc;
1703  
1704  	if (!rl) {
1705  		errno = EINVAL;
1706  		ntfs_log_perror("%s: ", __FUNCTION__);
1707  		return -1;
1708  	}
1709  
1710  	for (rlc = rl; rlc->length; rlc++)
1711  		if (rlc->lcn < 0) {
1712  			if (rlc->lcn != LCN_HOLE) {
1713  				errno = EINVAL;
1714  				ntfs_log_perror("%s: bad runlist", __FUNCTION__);
1715  				return -1;
1716  			}
1717  			return 1;
1718  		}
1719  	return 0;
1720  }
1721  
1722  /**
1723   * ntfs_rl_get_compressed_size - calculate length of non sparse regions
1724   * @vol:	ntfs volume (need for cluster size)
1725   * @rl:		runlist to calculate for
1726   *
1727   * Return compressed size or -1 on error with errno set to the error code.
1728   */
1729  s64 ntfs_rl_get_compressed_size(ntfs_volume *vol, runlist *rl)
1730  {
1731  	runlist *rlc;
1732  	s64 ret = 0;
1733  
1734  	if (!rl) {
1735  		errno = EINVAL;
1736  		ntfs_log_perror("%s: ", __FUNCTION__);
1737  		return -1;
1738  	}
1739  
1740  	for (rlc = rl; rlc->length; rlc++) {
1741  		if (rlc->lcn < 0) {
1742  			if (rlc->lcn != LCN_HOLE) {
1743  				errno = EINVAL;
1744  				ntfs_log_perror("%s: bad runlist", __FUNCTION__);
1745  				return -1;
1746  			}
1747  		} else
1748  			ret += rlc->length;
1749  	}
1750  	return ret << vol->cluster_size_bits;
1751  }
1752  
1753  
1754  #ifdef NTFS_TEST
1755  /**
1756   * test_rl_helper
1757   */
1758  #define MKRL(R,V,L,S)				\
1759  	(R)->vcn = V;				\
1760  	(R)->lcn = L;				\
1761  	(R)->length = S;
1762  /*
1763  }
1764  */
1765  /**
1766   * test_rl_dump_runlist - Runlist test: Display the contents of a runlist
1767   * @rl:
1768   *
1769   * Description...
1770   *
1771   * Returns:
1772   */
1773  static void test_rl_dump_runlist(const runlist_element *rl)
1774  {
1775  	int abbr = 0;	/* abbreviate long lists */
1776  	int len = 0;
1777  	int i;
1778  	const char *lcn_str[5] = { "HOLE", "NOTMAP", "ENOENT", "XXXX" };
1779  
1780  	if (!rl) {
1781  		printf("    Run list not present.\n");
1782  		return;
1783  	}
1784  
1785  	if (abbr)
1786  		for (len = 0; rl[len].length; len++) ;
1787  
1788  	printf("     VCN      LCN      len\n");
1789  	for (i = 0; ; i++, rl++) {
1790  		LCN lcn = rl->lcn;
1791  
1792  		if ((abbr) && (len > 20)) {
1793  			if (i == 4)
1794  				printf("     ...\n");
1795  			if ((i > 3) && (i < (len - 3)))
1796  				continue;
1797  		}
1798  
1799  		if (lcn < (LCN)0) {
1800  			int ind = -lcn - 1;
1801  
1802  			if (ind > -LCN_ENOENT - 1)
1803  				ind = 3;
1804  			printf("%8lld %8s %8lld\n",
1805  				rl->vcn, lcn_str[ind], rl->length);
1806  		} else
1807  			printf("%8lld %8lld %8lld\n",
1808  				rl->vcn, rl->lcn, rl->length);
1809  		if (!rl->length)
1810  			break;
1811  	}
1812  	if ((abbr) && (len > 20))
1813  		printf("    (%d entries)\n", len+1);
1814  	printf("\n");
1815  }
1816  
1817  /**
1818   * test_rl_runlists_merge - Runlist test: Merge two runlists
1819   * @drl:
1820   * @srl:
1821   *
1822   * Description...
1823   *
1824   * Returns:
1825   */
1826  static runlist_element * test_rl_runlists_merge(runlist_element *drl, runlist_element *srl)
1827  {
1828  	runlist_element *res = NULL;
1829  
1830  	printf("dst:\n");
1831  	test_rl_dump_runlist(drl);
1832  	printf("src:\n");
1833  	test_rl_dump_runlist(srl);
1834  
1835  	res = ntfs_runlists_merge(drl, srl);
1836  
1837  	printf("res:\n");
1838  	test_rl_dump_runlist(res);
1839  
1840  	return res;
1841  }
1842  
1843  /**
1844   * test_rl_read_buffer - Runlist test: Read a file containing a runlist
1845   * @file:
1846   * @buf:
1847   * @bufsize:
1848   *
1849   * Description...
1850   *
1851   * Returns:
1852   */
1853  static int test_rl_read_buffer(const char *file, u8 *buf, int bufsize)
1854  {
1855  	FILE *fptr;
1856  
1857  	fptr = fopen(file, "r");
1858  	if (!fptr) {
1859  		printf("open %s\n", file);
1860  		return 0;
1861  	}
1862  
1863  	if (fread(buf, bufsize, 1, fptr) == 99) {
1864  		printf("read %s\n", file);
1865  		return 0;
1866  	}
1867  
1868  	fclose(fptr);
1869  	return 1;
1870  }
1871  
1872  /**
1873   * test_rl_pure_src - Runlist test: Complicate the simple tests a little
1874   * @contig:
1875   * @multi:
1876   * @vcn:
1877   * @len:
1878   *
1879   * Description...
1880   *
1881   * Returns:
1882   */
1883  static runlist_element * test_rl_pure_src(BOOL contig, BOOL multi, int vcn, int len)
1884  {
1885  	runlist_element *result;
1886  	int fudge;
1887  
1888  	if (contig)
1889  		fudge = 0;
1890  	else
1891  		fudge = 999;
1892  
1893  	result = ntfs_malloc(4096);
1894  	if (!result)
1895  		return NULL;
1896  
1897  	if (multi) {
1898  		MKRL(result+0, vcn + (0*len/4), fudge + vcn + 1000 + (0*len/4), len / 4)
1899  		MKRL(result+1, vcn + (1*len/4), fudge + vcn + 1000 + (1*len/4), len / 4)
1900  		MKRL(result+2, vcn + (2*len/4), fudge + vcn + 1000 + (2*len/4), len / 4)
1901  		MKRL(result+3, vcn + (3*len/4), fudge + vcn + 1000 + (3*len/4), len / 4)
1902  		MKRL(result+4, vcn + (4*len/4), LCN_RL_NOT_MAPPED,              0)
1903  	} else {
1904  		MKRL(result+0, vcn,       fudge + vcn + 1000, len)
1905  		MKRL(result+1, vcn + len, LCN_RL_NOT_MAPPED,  0)
1906  	}
1907  	return result;
1908  }
1909  
1910  /**
1911   * test_rl_pure_test - Runlist test: Perform tests using simple runlists
1912   * @test:
1913   * @contig:
1914   * @multi:
1915   * @vcn:
1916   * @len:
1917   * @file:
1918   * @size:
1919   *
1920   * Description...
1921   *
1922   * Returns:
1923   */
1924  static void test_rl_pure_test(int test, BOOL contig, BOOL multi, int vcn, int len, runlist_element *file, int size)
1925  {
1926  	runlist_element *src;
1927  	runlist_element *dst;
1928  	runlist_element *res;
1929  
1930  	src = test_rl_pure_src(contig, multi, vcn, len);
1931  	dst = ntfs_malloc(4096);
1932  	if (!src || !dst) {
1933  		printf("Test %2d ---------- FAILED! (no free memory?)\n", test);
1934  		return;
1935  	}
1936  
1937  	memcpy(dst, file, size);
1938  
1939  	printf("Test %2d ----------\n", test);
1940  	res = test_rl_runlists_merge(dst, src);
1941  
1942  	free(res);
1943  }
1944  
1945  /**
1946   * test_rl_pure - Runlist test: Create tests using simple runlists
1947   * @contig:
1948   * @multi:
1949   *
1950   * Description...
1951   *
1952   * Returns:
1953   */
1954  static void test_rl_pure(char *contig, char *multi)
1955  {
1956  		/* VCN,  LCN, len */
1957  	static runlist_element file1[] = {
1958  		{    0,   -1, 100 },	/* HOLE */
1959  		{  100, 1100, 100 },	/* DATA */
1960  		{  200,   -1, 100 },	/* HOLE */
1961  		{  300, 1300, 100 },	/* DATA */
1962  		{  400,   -1, 100 },	/* HOLE */
1963  		{  500,   -3,   0 }	/* NOENT */
1964  	};
1965  	static runlist_element file2[] = {
1966  		{    0, 1000, 100 },	/* DATA */
1967  		{  100,   -1, 100 },	/* HOLE */
1968  		{  200,   -3,   0 }	/* NOENT */
1969  	};
1970  	static runlist_element file3[] = {
1971  		{    0, 1000, 100 },	/* DATA */
1972  		{  100,   -3,   0 }	/* NOENT */
1973  	};
1974  	static runlist_element file4[] = {
1975  		{    0,   -3,   0 }	/* NOENT */
1976  	};
1977  	static runlist_element file5[] = {
1978  		{    0,   -2, 100 },	/* NOTMAP */
1979  		{  100, 1100, 100 },	/* DATA */
1980  		{  200,   -2, 100 },	/* NOTMAP */
1981  		{  300, 1300, 100 },	/* DATA */
1982  		{  400,   -2, 100 },	/* NOTMAP */
1983  		{  500,   -3,   0 }	/* NOENT */
1984  	};
1985  	static runlist_element file6[] = {
1986  		{    0, 1000, 100 },	/* DATA */
1987  		{  100,   -2, 100 },	/* NOTMAP */
1988  		{  200,   -3,   0 }	/* NOENT */
1989  	};
1990  	BOOL c, m;
1991  
1992  	if (strcmp(contig, "contig") == 0)
1993  		c = TRUE;
1994  	else if (strcmp(contig, "noncontig") == 0)
1995  		c = FALSE;
1996  	else {
1997  		printf("rl pure [contig|noncontig] [single|multi]\n");
1998  		return;
1999  	}
2000  	if (strcmp(multi, "multi") == 0)
2001  		m = TRUE;
2002  	else if (strcmp(multi, "single") == 0)
2003  		m = FALSE;
2004  	else {
2005  		printf("rl pure [contig|noncontig] [single|multi]\n");
2006  		return;
2007  	}
2008  
2009  	test_rl_pure_test(1,  c, m,   0,  40, file1, sizeof(file1));
2010  	test_rl_pure_test(2,  c, m,  40,  40, file1, sizeof(file1));
2011  	test_rl_pure_test(3,  c, m,  60,  40, file1, sizeof(file1));
2012  	test_rl_pure_test(4,  c, m,   0, 100, file1, sizeof(file1));
2013  	test_rl_pure_test(5,  c, m, 200,  40, file1, sizeof(file1));
2014  	test_rl_pure_test(6,  c, m, 240,  40, file1, sizeof(file1));
2015  	test_rl_pure_test(7,  c, m, 260,  40, file1, sizeof(file1));
2016  	test_rl_pure_test(8,  c, m, 200, 100, file1, sizeof(file1));
2017  	test_rl_pure_test(9,  c, m, 400,  40, file1, sizeof(file1));
2018  	test_rl_pure_test(10, c, m, 440,  40, file1, sizeof(file1));
2019  	test_rl_pure_test(11, c, m, 460,  40, file1, sizeof(file1));
2020  	test_rl_pure_test(12, c, m, 400, 100, file1, sizeof(file1));
2021  	test_rl_pure_test(13, c, m, 160, 100, file2, sizeof(file2));
2022  	test_rl_pure_test(14, c, m, 100, 140, file2, sizeof(file2));
2023  	test_rl_pure_test(15, c, m, 200,  40, file2, sizeof(file2));
2024  	test_rl_pure_test(16, c, m, 240,  40, file2, sizeof(file2));
2025  	test_rl_pure_test(17, c, m, 100,  40, file3, sizeof(file3));
2026  	test_rl_pure_test(18, c, m, 140,  40, file3, sizeof(file3));
2027  	test_rl_pure_test(19, c, m,   0,  40, file4, sizeof(file4));
2028  	test_rl_pure_test(20, c, m,  40,  40, file4, sizeof(file4));
2029  	test_rl_pure_test(21, c, m,   0,  40, file5, sizeof(file5));
2030  	test_rl_pure_test(22, c, m,  40,  40, file5, sizeof(file5));
2031  	test_rl_pure_test(23, c, m,  60,  40, file5, sizeof(file5));
2032  	test_rl_pure_test(24, c, m,   0, 100, file5, sizeof(file5));
2033  	test_rl_pure_test(25, c, m, 200,  40, file5, sizeof(file5));
2034  	test_rl_pure_test(26, c, m, 240,  40, file5, sizeof(file5));
2035  	test_rl_pure_test(27, c, m, 260,  40, file5, sizeof(file5));
2036  	test_rl_pure_test(28, c, m, 200, 100, file5, sizeof(file5));
2037  	test_rl_pure_test(29, c, m, 400,  40, file5, sizeof(file5));
2038  	test_rl_pure_test(30, c, m, 440,  40, file5, sizeof(file5));
2039  	test_rl_pure_test(31, c, m, 460,  40, file5, sizeof(file5));
2040  	test_rl_pure_test(32, c, m, 400, 100, file5, sizeof(file5));
2041  	test_rl_pure_test(33, c, m, 160, 100, file6, sizeof(file6));
2042  	test_rl_pure_test(34, c, m, 100, 140, file6, sizeof(file6));
2043  }
2044  
2045  /**
2046   * test_rl_zero - Runlist test: Merge a zero-length runlist
2047   *
2048   * Description...
2049   *
2050   * Returns:
2051   */
2052  static void test_rl_zero(void)
2053  {
2054  	runlist_element *jim = NULL;
2055  	runlist_element *bob = NULL;
2056  
2057  	bob = calloc(3, sizeof(runlist_element));
2058  	if (!bob)
2059  		return;
2060  
2061  	MKRL(bob+0, 10, 99, 5)
2062  	MKRL(bob+1, 15, LCN_RL_NOT_MAPPED, 0)
2063  
2064  	jim = test_rl_runlists_merge(jim, bob);
2065  	if (!jim)
2066  		return;
2067  
2068  	free(jim);
2069  }
2070  
2071  /**
2072   * test_rl_frag_combine - Runlist test: Perform tests using fragmented files
2073   * @vol:
2074   * @attr1:
2075   * @attr2:
2076   * @attr3:
2077   *
2078   * Description...
2079   *
2080   * Returns:
2081   */
2082  static void test_rl_frag_combine(ntfs_volume *vol, ATTR_RECORD *attr1, ATTR_RECORD *attr2, ATTR_RECORD *attr3)
2083  {
2084  	runlist_element *run1;
2085  	runlist_element *run2;
2086  	runlist_element *run3;
2087  
2088  	run1 = ntfs_mapping_pairs_decompress(vol, attr1, NULL);
2089  	if (!run1)
2090  		return;
2091  
2092  	run2 = ntfs_mapping_pairs_decompress(vol, attr2, NULL);
2093  	if (!run2)
2094  		return;
2095  
2096  	run1 = test_rl_runlists_merge(run1, run2);
2097  
2098  	run3 = ntfs_mapping_pairs_decompress(vol, attr3, NULL);
2099  	if (!run3)
2100  		return;
2101  
2102  	run1 = test_rl_runlists_merge(run1, run3);
2103  
2104  	free(run1);
2105  }
2106  
2107  /**
2108   * test_rl_frag - Runlist test: Create tests using very fragmented files
2109   * @test:
2110   *
2111   * Description...
2112   *
2113   * Returns:
2114   */
2115  static void test_rl_frag(char *test)
2116  {
2117  	ntfs_volume vol;
2118  	ATTR_RECORD *attr1 = ntfs_malloc(1024);
2119  	ATTR_RECORD *attr2 = ntfs_malloc(1024);
2120  	ATTR_RECORD *attr3 = ntfs_malloc(1024);
2121  
2122  	if (!attr1 || !attr2 || !attr3)
2123  		goto out;
2124  
2125  	vol.sb = NULL;
2126  	vol.sector_size_bits = 9;
2127  	vol.cluster_size = 2048;
2128  	vol.cluster_size_bits = 11;
2129  	vol.major_ver = 3;
2130  
2131  	if (!test_rl_read_buffer("runlist-data/attr1.bin", (u8*) attr1, 1024))
2132  		goto out;
2133  	if (!test_rl_read_buffer("runlist-data/attr2.bin", (u8*) attr2, 1024))
2134  		goto out;
2135  	if (!test_rl_read_buffer("runlist-data/attr3.bin", (u8*) attr3, 1024))
2136  		goto out;
2137  
2138  	if      (strcmp(test, "123") == 0)  test_rl_frag_combine(&vol, attr1, attr2, attr3);
2139  	else if (strcmp(test, "132") == 0)  test_rl_frag_combine(&vol, attr1, attr3, attr2);
2140  	else if (strcmp(test, "213") == 0)  test_rl_frag_combine(&vol, attr2, attr1, attr3);
2141  	else if (strcmp(test, "231") == 0)  test_rl_frag_combine(&vol, attr2, attr3, attr1);
2142  	else if (strcmp(test, "312") == 0)  test_rl_frag_combine(&vol, attr3, attr1, attr2);
2143  	else if (strcmp(test, "321") == 0)  test_rl_frag_combine(&vol, attr3, attr2, attr1);
2144  	else
2145  		printf("Frag: No such test '%s'\n", test);
2146  
2147  out:
2148  	free(attr1);
2149  	free(attr2);
2150  	free(attr3);
2151  }
2152  
2153  /**
2154   * test_rl_main - Runlist test: Program start (main)
2155   * @argc:
2156   * @argv:
2157   *
2158   * Description...
2159   *
2160   * Returns:
2161   */
2162  int test_rl_main(int argc, char *argv[])
2163  {
2164  	if      ((argc == 2) && (strcmp(argv[1], "zero") == 0)) test_rl_zero();
2165  	else if ((argc == 3) && (strcmp(argv[1], "frag") == 0)) test_rl_frag(argv[2]);
2166  	else if ((argc == 4) && (strcmp(argv[1], "pure") == 0)) test_rl_pure(argv[2], argv[3]);
2167  	else
2168  		printf("rl [zero|frag|pure] {args}\n");
2169  
2170  	return 0;
2171  }
2172  
2173  #endif
2174  
2175