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1/*
2 * linux/net/sunrpc/xdr.c
3 *
4 * Generic XDR support.
5 *
6 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
7 */
8
9#include <linux/module.h>
10#include <linux/slab.h>
11#include <linux/types.h>
12#include <linux/string.h>
13#include <linux/kernel.h>
14#include <linux/pagemap.h>
15#include <linux/errno.h>
16#include <linux/sunrpc/xdr.h>
17#include <linux/sunrpc/msg_prot.h>
18
19/*
20 * XDR functions for basic NFS types
21 */
22__be32 *
23xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
24{
25 unsigned int quadlen = XDR_QUADLEN(obj->len);
26
27 p[quadlen] = 0; /* zero trailing bytes */
28 *p++ = cpu_to_be32(obj->len);
29 memcpy(p, obj->data, obj->len);
30 return p + XDR_QUADLEN(obj->len);
31}
32EXPORT_SYMBOL_GPL(xdr_encode_netobj);
33
34__be32 *
35xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
36{
37 unsigned int len;
38
39 if ((len = be32_to_cpu(*p++)) > XDR_MAX_NETOBJ)
40 return NULL;
41 obj->len = len;
42 obj->data = (u8 *) p;
43 return p + XDR_QUADLEN(len);
44}
45EXPORT_SYMBOL_GPL(xdr_decode_netobj);
46
47/**
48 * xdr_encode_opaque_fixed - Encode fixed length opaque data
49 * @p: pointer to current position in XDR buffer.
50 * @ptr: pointer to data to encode (or NULL)
51 * @nbytes: size of data.
52 *
53 * Copy the array of data of length nbytes at ptr to the XDR buffer
54 * at position p, then align to the next 32-bit boundary by padding
55 * with zero bytes (see RFC1832).
56 * Note: if ptr is NULL, only the padding is performed.
57 *
58 * Returns the updated current XDR buffer position
59 *
60 */
61__be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
62{
63 if (likely(nbytes != 0)) {
64 unsigned int quadlen = XDR_QUADLEN(nbytes);
65 unsigned int padding = (quadlen << 2) - nbytes;
66
67 if (ptr != NULL)
68 memcpy(p, ptr, nbytes);
69 if (padding != 0)
70 memset((char *)p + nbytes, 0, padding);
71 p += quadlen;
72 }
73 return p;
74}
75EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed);
76
77/**
78 * xdr_encode_opaque - Encode variable length opaque data
79 * @p: pointer to current position in XDR buffer.
80 * @ptr: pointer to data to encode (or NULL)
81 * @nbytes: size of data.
82 *
83 * Returns the updated current XDR buffer position
84 */
85__be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
86{
87 *p++ = cpu_to_be32(nbytes);
88 return xdr_encode_opaque_fixed(p, ptr, nbytes);
89}
90EXPORT_SYMBOL_GPL(xdr_encode_opaque);
91
92__be32 *
93xdr_encode_string(__be32 *p, const char *string)
94{
95 return xdr_encode_array(p, string, strlen(string));
96}
97EXPORT_SYMBOL_GPL(xdr_encode_string);
98
99__be32 *
100xdr_decode_string_inplace(__be32 *p, char **sp,
101 unsigned int *lenp, unsigned int maxlen)
102{
103 u32 len;
104
105 len = be32_to_cpu(*p++);
106 if (len > maxlen)
107 return NULL;
108 *lenp = len;
109 *sp = (char *) p;
110 return p + XDR_QUADLEN(len);
111}
112EXPORT_SYMBOL_GPL(xdr_decode_string_inplace);
113
114/**
115 * xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
116 * @buf: XDR buffer where string resides
117 * @len: length of string, in bytes
118 *
119 */
120void
121xdr_terminate_string(struct xdr_buf *buf, const u32 len)
122{
123 char *kaddr;
124
125 kaddr = kmap_atomic(buf->pages[0]);
126 kaddr[buf->page_base + len] = '\0';
127 kunmap_atomic(kaddr);
128}
129EXPORT_SYMBOL_GPL(xdr_terminate_string);
130
131void
132xdr_encode_pages(struct xdr_buf *xdr, struct page **pages, unsigned int base,
133 unsigned int len)
134{
135 struct kvec *tail = xdr->tail;
136 u32 *p;
137
138 xdr->pages = pages;
139 xdr->page_base = base;
140 xdr->page_len = len;
141
142 p = (u32 *)xdr->head[0].iov_base + XDR_QUADLEN(xdr->head[0].iov_len);
143 tail->iov_base = p;
144 tail->iov_len = 0;
145
146 if (len & 3) {
147 unsigned int pad = 4 - (len & 3);
148
149 *p = 0;
150 tail->iov_base = (char *)p + (len & 3);
151 tail->iov_len = pad;
152 len += pad;
153 }
154 xdr->buflen += len;
155 xdr->len += len;
156}
157EXPORT_SYMBOL_GPL(xdr_encode_pages);
158
159void
160xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
161 struct page **pages, unsigned int base, unsigned int len)
162{
163 struct kvec *head = xdr->head;
164 struct kvec *tail = xdr->tail;
165 char *buf = (char *)head->iov_base;
166 unsigned int buflen = head->iov_len;
167
168 head->iov_len = offset;
169
170 xdr->pages = pages;
171 xdr->page_base = base;
172 xdr->page_len = len;
173
174 tail->iov_base = buf + offset;
175 tail->iov_len = buflen - offset;
176
177 xdr->buflen += len;
178}
179EXPORT_SYMBOL_GPL(xdr_inline_pages);
180
181/*
182 * Helper routines for doing 'memmove' like operations on a struct xdr_buf
183 *
184 * _shift_data_right_pages
185 * @pages: vector of pages containing both the source and dest memory area.
186 * @pgto_base: page vector address of destination
187 * @pgfrom_base: page vector address of source
188 * @len: number of bytes to copy
189 *
190 * Note: the addresses pgto_base and pgfrom_base are both calculated in
191 * the same way:
192 * if a memory area starts at byte 'base' in page 'pages[i]',
193 * then its address is given as (i << PAGE_CACHE_SHIFT) + base
194 * Also note: pgfrom_base must be < pgto_base, but the memory areas
195 * they point to may overlap.
196 */
197static void
198_shift_data_right_pages(struct page **pages, size_t pgto_base,
199 size_t pgfrom_base, size_t len)
200{
201 struct page **pgfrom, **pgto;
202 char *vfrom, *vto;
203 size_t copy;
204
205 BUG_ON(pgto_base <= pgfrom_base);
206
207 pgto_base += len;
208 pgfrom_base += len;
209
210 pgto = pages + (pgto_base >> PAGE_CACHE_SHIFT);
211 pgfrom = pages + (pgfrom_base >> PAGE_CACHE_SHIFT);
212
213 pgto_base &= ~PAGE_CACHE_MASK;
214 pgfrom_base &= ~PAGE_CACHE_MASK;
215
216 do {
217 /* Are any pointers crossing a page boundary? */
218 if (pgto_base == 0) {
219 pgto_base = PAGE_CACHE_SIZE;
220 pgto--;
221 }
222 if (pgfrom_base == 0) {
223 pgfrom_base = PAGE_CACHE_SIZE;
224 pgfrom--;
225 }
226
227 copy = len;
228 if (copy > pgto_base)
229 copy = pgto_base;
230 if (copy > pgfrom_base)
231 copy = pgfrom_base;
232 pgto_base -= copy;
233 pgfrom_base -= copy;
234
235 vto = kmap_atomic(*pgto);
236 vfrom = kmap_atomic(*pgfrom);
237 memmove(vto + pgto_base, vfrom + pgfrom_base, copy);
238 flush_dcache_page(*pgto);
239 kunmap_atomic(vfrom);
240 kunmap_atomic(vto);
241
242 } while ((len -= copy) != 0);
243}
244
245/*
246 * _copy_to_pages
247 * @pages: array of pages
248 * @pgbase: page vector address of destination
249 * @p: pointer to source data
250 * @len: length
251 *
252 * Copies data from an arbitrary memory location into an array of pages
253 * The copy is assumed to be non-overlapping.
254 */
255static void
256_copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
257{
258 struct page **pgto;
259 char *vto;
260 size_t copy;
261
262 pgto = pages + (pgbase >> PAGE_CACHE_SHIFT);
263 pgbase &= ~PAGE_CACHE_MASK;
264
265 for (;;) {
266 copy = PAGE_CACHE_SIZE - pgbase;
267 if (copy > len)
268 copy = len;
269
270 vto = kmap_atomic(*pgto);
271 memcpy(vto + pgbase, p, copy);
272 kunmap_atomic(vto);
273
274 len -= copy;
275 if (len == 0)
276 break;
277
278 pgbase += copy;
279 if (pgbase == PAGE_CACHE_SIZE) {
280 flush_dcache_page(*pgto);
281 pgbase = 0;
282 pgto++;
283 }
284 p += copy;
285 }
286 flush_dcache_page(*pgto);
287}
288
289/*
290 * _copy_from_pages
291 * @p: pointer to destination
292 * @pages: array of pages
293 * @pgbase: offset of source data
294 * @len: length
295 *
296 * Copies data into an arbitrary memory location from an array of pages
297 * The copy is assumed to be non-overlapping.
298 */
299void
300_copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
301{
302 struct page **pgfrom;
303 char *vfrom;
304 size_t copy;
305
306 pgfrom = pages + (pgbase >> PAGE_CACHE_SHIFT);
307 pgbase &= ~PAGE_CACHE_MASK;
308
309 do {
310 copy = PAGE_CACHE_SIZE - pgbase;
311 if (copy > len)
312 copy = len;
313
314 vfrom = kmap_atomic(*pgfrom);
315 memcpy(p, vfrom + pgbase, copy);
316 kunmap_atomic(vfrom);
317
318 pgbase += copy;
319 if (pgbase == PAGE_CACHE_SIZE) {
320 pgbase = 0;
321 pgfrom++;
322 }
323 p += copy;
324
325 } while ((len -= copy) != 0);
326}
327EXPORT_SYMBOL_GPL(_copy_from_pages);
328
329/*
330 * xdr_shrink_bufhead
331 * @buf: xdr_buf
332 * @len: bytes to remove from buf->head[0]
333 *
334 * Shrinks XDR buffer's header kvec buf->head[0] by
335 * 'len' bytes. The extra data is not lost, but is instead
336 * moved into the inlined pages and/or the tail.
337 */
338static void
339xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
340{
341 struct kvec *head, *tail;
342 size_t copy, offs;
343 unsigned int pglen = buf->page_len;
344
345 tail = buf->tail;
346 head = buf->head;
347 BUG_ON (len > head->iov_len);
348
349 /* Shift the tail first */
350 if (tail->iov_len != 0) {
351 if (tail->iov_len > len) {
352 copy = tail->iov_len - len;
353 memmove((char *)tail->iov_base + len,
354 tail->iov_base, copy);
355 }
356 /* Copy from the inlined pages into the tail */
357 copy = len;
358 if (copy > pglen)
359 copy = pglen;
360 offs = len - copy;
361 if (offs >= tail->iov_len)
362 copy = 0;
363 else if (copy > tail->iov_len - offs)
364 copy = tail->iov_len - offs;
365 if (copy != 0)
366 _copy_from_pages((char *)tail->iov_base + offs,
367 buf->pages,
368 buf->page_base + pglen + offs - len,
369 copy);
370 /* Do we also need to copy data from the head into the tail ? */
371 if (len > pglen) {
372 offs = copy = len - pglen;
373 if (copy > tail->iov_len)
374 copy = tail->iov_len;
375 memcpy(tail->iov_base,
376 (char *)head->iov_base +
377 head->iov_len - offs,
378 copy);
379 }
380 }
381 /* Now handle pages */
382 if (pglen != 0) {
383 if (pglen > len)
384 _shift_data_right_pages(buf->pages,
385 buf->page_base + len,
386 buf->page_base,
387 pglen - len);
388 copy = len;
389 if (len > pglen)
390 copy = pglen;
391 _copy_to_pages(buf->pages, buf->page_base,
392 (char *)head->iov_base + head->iov_len - len,
393 copy);
394 }
395 head->iov_len -= len;
396 buf->buflen -= len;
397 /* Have we truncated the message? */
398 if (buf->len > buf->buflen)
399 buf->len = buf->buflen;
400}
401
402/*
403 * xdr_shrink_pagelen
404 * @buf: xdr_buf
405 * @len: bytes to remove from buf->pages
406 *
407 * Shrinks XDR buffer's page array buf->pages by
408 * 'len' bytes. The extra data is not lost, but is instead
409 * moved into the tail.
410 */
411static void
412xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
413{
414 struct kvec *tail;
415 size_t copy;
416 unsigned int pglen = buf->page_len;
417 unsigned int tailbuf_len;
418
419 tail = buf->tail;
420 BUG_ON (len > pglen);
421
422 tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
423
424 /* Shift the tail first */
425 if (tailbuf_len != 0) {
426 unsigned int free_space = tailbuf_len - tail->iov_len;
427
428 if (len < free_space)
429 free_space = len;
430 tail->iov_len += free_space;
431
432 copy = len;
433 if (tail->iov_len > len) {
434 char *p = (char *)tail->iov_base + len;
435 memmove(p, tail->iov_base, tail->iov_len - len);
436 } else
437 copy = tail->iov_len;
438 /* Copy from the inlined pages into the tail */
439 _copy_from_pages((char *)tail->iov_base,
440 buf->pages, buf->page_base + pglen - len,
441 copy);
442 }
443 buf->page_len -= len;
444 buf->buflen -= len;
445 /* Have we truncated the message? */
446 if (buf->len > buf->buflen)
447 buf->len = buf->buflen;
448}
449
450void
451xdr_shift_buf(struct xdr_buf *buf, size_t len)
452{
453 xdr_shrink_bufhead(buf, len);
454}
455EXPORT_SYMBOL_GPL(xdr_shift_buf);
456
457/**
458 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
459 * @xdr: pointer to xdr_stream struct
460 * @buf: pointer to XDR buffer in which to encode data
461 * @p: current pointer inside XDR buffer
462 *
463 * Note: at the moment the RPC client only passes the length of our
464 * scratch buffer in the xdr_buf's header kvec. Previously this
465 * meant we needed to call xdr_adjust_iovec() after encoding the
466 * data. With the new scheme, the xdr_stream manages the details
467 * of the buffer length, and takes care of adjusting the kvec
468 * length for us.
469 */
470void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
471{
472 struct kvec *iov = buf->head;
473 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
474
475 BUG_ON(scratch_len < 0);
476 xdr->buf = buf;
477 xdr->iov = iov;
478 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
479 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
480 BUG_ON(iov->iov_len > scratch_len);
481
482 if (p != xdr->p && p != NULL) {
483 size_t len;
484
485 BUG_ON(p < xdr->p || p > xdr->end);
486 len = (char *)p - (char *)xdr->p;
487 xdr->p = p;
488 buf->len += len;
489 iov->iov_len += len;
490 }
491}
492EXPORT_SYMBOL_GPL(xdr_init_encode);
493
494/**
495 * xdr_reserve_space - Reserve buffer space for sending
496 * @xdr: pointer to xdr_stream
497 * @nbytes: number of bytes to reserve
498 *
499 * Checks that we have enough buffer space to encode 'nbytes' more
500 * bytes of data. If so, update the total xdr_buf length, and
501 * adjust the length of the current kvec.
502 */
503__be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
504{
505 __be32 *p = xdr->p;
506 __be32 *q;
507
508 /* align nbytes on the next 32-bit boundary */
509 nbytes += 3;
510 nbytes &= ~3;
511 q = p + (nbytes >> 2);
512 if (unlikely(q > xdr->end || q < p))
513 return NULL;
514 xdr->p = q;
515 xdr->iov->iov_len += nbytes;
516 xdr->buf->len += nbytes;
517 return p;
518}
519EXPORT_SYMBOL_GPL(xdr_reserve_space);
520
521/**
522 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
523 * @xdr: pointer to xdr_stream
524 * @pages: list of pages
525 * @base: offset of first byte
526 * @len: length of data in bytes
527 *
528 */
529void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
530 unsigned int len)
531{
532 struct xdr_buf *buf = xdr->buf;
533 struct kvec *iov = buf->tail;
534 buf->pages = pages;
535 buf->page_base = base;
536 buf->page_len = len;
537
538 iov->iov_base = (char *)xdr->p;
539 iov->iov_len = 0;
540 xdr->iov = iov;
541
542 if (len & 3) {
543 unsigned int pad = 4 - (len & 3);
544
545 BUG_ON(xdr->p >= xdr->end);
546 iov->iov_base = (char *)xdr->p + (len & 3);
547 iov->iov_len += pad;
548 len += pad;
549 *xdr->p++ = 0;
550 }
551 buf->buflen += len;
552 buf->len += len;
553}
554EXPORT_SYMBOL_GPL(xdr_write_pages);
555
556static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
557 __be32 *p, unsigned int len)
558{
559 if (len > iov->iov_len)
560 len = iov->iov_len;
561 if (p == NULL)
562 p = (__be32*)iov->iov_base;
563 xdr->p = p;
564 xdr->end = (__be32*)(iov->iov_base + len);
565 xdr->iov = iov;
566 xdr->page_ptr = NULL;
567}
568
569static int xdr_set_page_base(struct xdr_stream *xdr,
570 unsigned int base, unsigned int len)
571{
572 unsigned int pgnr;
573 unsigned int maxlen;
574 unsigned int pgoff;
575 unsigned int pgend;
576 void *kaddr;
577
578 maxlen = xdr->buf->page_len;
579 if (base >= maxlen)
580 return -EINVAL;
581 maxlen -= base;
582 if (len > maxlen)
583 len = maxlen;
584
585 base += xdr->buf->page_base;
586
587 pgnr = base >> PAGE_SHIFT;
588 xdr->page_ptr = &xdr->buf->pages[pgnr];
589 kaddr = page_address(*xdr->page_ptr);
590
591 pgoff = base & ~PAGE_MASK;
592 xdr->p = (__be32*)(kaddr + pgoff);
593
594 pgend = pgoff + len;
595 if (pgend > PAGE_SIZE)
596 pgend = PAGE_SIZE;
597 xdr->end = (__be32*)(kaddr + pgend);
598 xdr->iov = NULL;
599 return 0;
600}
601
602static void xdr_set_next_page(struct xdr_stream *xdr)
603{
604 unsigned int newbase;
605
606 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
607 newbase -= xdr->buf->page_base;
608
609 if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
610 xdr_set_iov(xdr, xdr->buf->tail, NULL, xdr->buf->len);
611}
612
613static bool xdr_set_next_buffer(struct xdr_stream *xdr)
614{
615 if (xdr->page_ptr != NULL)
616 xdr_set_next_page(xdr);
617 else if (xdr->iov == xdr->buf->head) {
618 if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
619 xdr_set_iov(xdr, xdr->buf->tail, NULL, xdr->buf->len);
620 }
621 return xdr->p != xdr->end;
622}
623
624/**
625 * xdr_init_decode - Initialize an xdr_stream for decoding data.
626 * @xdr: pointer to xdr_stream struct
627 * @buf: pointer to XDR buffer from which to decode data
628 * @p: current pointer inside XDR buffer
629 */
630void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
631{
632 xdr->buf = buf;
633 xdr->scratch.iov_base = NULL;
634 xdr->scratch.iov_len = 0;
635 if (buf->head[0].iov_len != 0)
636 xdr_set_iov(xdr, buf->head, p, buf->len);
637 else if (buf->page_len != 0)
638 xdr_set_page_base(xdr, 0, buf->len);
639}
640EXPORT_SYMBOL_GPL(xdr_init_decode);
641
642/**
643 * xdr_init_decode - Initialize an xdr_stream for decoding data.
644 * @xdr: pointer to xdr_stream struct
645 * @buf: pointer to XDR buffer from which to decode data
646 * @pages: list of pages to decode into
647 * @len: length in bytes of buffer in pages
648 */
649void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
650 struct page **pages, unsigned int len)
651{
652 memset(buf, 0, sizeof(*buf));
653 buf->pages = pages;
654 buf->page_len = len;
655 buf->buflen = len;
656 buf->len = len;
657 xdr_init_decode(xdr, buf, NULL);
658}
659EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
660
661static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
662{
663 __be32 *p = xdr->p;
664 __be32 *q = p + XDR_QUADLEN(nbytes);
665
666 if (unlikely(q > xdr->end || q < p))
667 return NULL;
668 xdr->p = q;
669 return p;
670}
671
672/**
673 * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
674 * @xdr: pointer to xdr_stream struct
675 * @buf: pointer to an empty buffer
676 * @buflen: size of 'buf'
677 *
678 * The scratch buffer is used when decoding from an array of pages.
679 * If an xdr_inline_decode() call spans across page boundaries, then
680 * we copy the data into the scratch buffer in order to allow linear
681 * access.
682 */
683void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
684{
685 xdr->scratch.iov_base = buf;
686 xdr->scratch.iov_len = buflen;
687}
688EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
689
690static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
691{
692 __be32 *p;
693 void *cpdest = xdr->scratch.iov_base;
694 size_t cplen = (char *)xdr->end - (char *)xdr->p;
695
696 if (nbytes > xdr->scratch.iov_len)
697 return NULL;
698 memcpy(cpdest, xdr->p, cplen);
699 cpdest += cplen;
700 nbytes -= cplen;
701 if (!xdr_set_next_buffer(xdr))
702 return NULL;
703 p = __xdr_inline_decode(xdr, nbytes);
704 if (p == NULL)
705 return NULL;
706 memcpy(cpdest, p, nbytes);
707 return xdr->scratch.iov_base;
708}
709
710/**
711 * xdr_inline_decode - Retrieve XDR data to decode
712 * @xdr: pointer to xdr_stream struct
713 * @nbytes: number of bytes of data to decode
714 *
715 * Check if the input buffer is long enough to enable us to decode
716 * 'nbytes' more bytes of data starting at the current position.
717 * If so return the current pointer, then update the current
718 * pointer position.
719 */
720__be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
721{
722 __be32 *p;
723
724 if (nbytes == 0)
725 return xdr->p;
726 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
727 return NULL;
728 p = __xdr_inline_decode(xdr, nbytes);
729 if (p != NULL)
730 return p;
731 return xdr_copy_to_scratch(xdr, nbytes);
732}
733EXPORT_SYMBOL_GPL(xdr_inline_decode);
734
735/**
736 * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
737 * @xdr: pointer to xdr_stream struct
738 * @len: number of bytes of page data
739 *
740 * Moves data beyond the current pointer position from the XDR head[] buffer
741 * into the page list. Any data that lies beyond current position + "len"
742 * bytes is moved into the XDR tail[].
743 */
744void xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
745{
746 struct xdr_buf *buf = xdr->buf;
747 struct kvec *iov;
748 ssize_t shift;
749 unsigned int end;
750 int padding;
751
752 /* Realign pages to current pointer position */
753 iov = buf->head;
754 shift = iov->iov_len + (char *)iov->iov_base - (char *)xdr->p;
755 if (shift > 0)
756 xdr_shrink_bufhead(buf, shift);
757
758 /* Truncate page data and move it into the tail */
759 if (buf->page_len > len)
760 xdr_shrink_pagelen(buf, buf->page_len - len);
761 padding = (XDR_QUADLEN(len) << 2) - len;
762 xdr->iov = iov = buf->tail;
763 /* Compute remaining message length. */
764 end = iov->iov_len;
765 shift = buf->buflen - buf->len;
766 if (shift < end)
767 end -= shift;
768 else if (shift > 0)
769 end = 0;
770 /*
771 * Position current pointer at beginning of tail, and
772 * set remaining message length.
773 */
774 xdr->p = (__be32 *)((char *)iov->iov_base + padding);
775 xdr->end = (__be32 *)((char *)iov->iov_base + end);
776}
777EXPORT_SYMBOL_GPL(xdr_read_pages);
778
779/**
780 * xdr_enter_page - decode data from the XDR page
781 * @xdr: pointer to xdr_stream struct
782 * @len: number of bytes of page data
783 *
784 * Moves data beyond the current pointer position from the XDR head[] buffer
785 * into the page list. Any data that lies beyond current position + "len"
786 * bytes is moved into the XDR tail[]. The current pointer is then
787 * repositioned at the beginning of the first XDR page.
788 */
789void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
790{
791 xdr_read_pages(xdr, len);
792 /*
793 * Position current pointer at beginning of tail, and
794 * set remaining message length.
795 */
796 xdr_set_page_base(xdr, 0, len);
797}
798EXPORT_SYMBOL_GPL(xdr_enter_page);
799
800static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
801
802void
803xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
804{
805 buf->head[0] = *iov;
806 buf->tail[0] = empty_iov;
807 buf->page_len = 0;
808 buf->buflen = buf->len = iov->iov_len;
809}
810EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
811
812/* Sets subbuf to the portion of buf of length len beginning base bytes
813 * from the start of buf. Returns -1 if base of length are out of bounds. */
814int
815xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
816 unsigned int base, unsigned int len)
817{
818 subbuf->buflen = subbuf->len = len;
819 if (base < buf->head[0].iov_len) {
820 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
821 subbuf->head[0].iov_len = min_t(unsigned int, len,
822 buf->head[0].iov_len - base);
823 len -= subbuf->head[0].iov_len;
824 base = 0;
825 } else {
826 subbuf->head[0].iov_base = NULL;
827 subbuf->head[0].iov_len = 0;
828 base -= buf->head[0].iov_len;
829 }
830
831 if (base < buf->page_len) {
832 subbuf->page_len = min(buf->page_len - base, len);
833 base += buf->page_base;
834 subbuf->page_base = base & ~PAGE_CACHE_MASK;
835 subbuf->pages = &buf->pages[base >> PAGE_CACHE_SHIFT];
836 len -= subbuf->page_len;
837 base = 0;
838 } else {
839 base -= buf->page_len;
840 subbuf->page_len = 0;
841 }
842
843 if (base < buf->tail[0].iov_len) {
844 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
845 subbuf->tail[0].iov_len = min_t(unsigned int, len,
846 buf->tail[0].iov_len - base);
847 len -= subbuf->tail[0].iov_len;
848 base = 0;
849 } else {
850 subbuf->tail[0].iov_base = NULL;
851 subbuf->tail[0].iov_len = 0;
852 base -= buf->tail[0].iov_len;
853 }
854
855 if (base || len)
856 return -1;
857 return 0;
858}
859EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
860
861static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
862{
863 unsigned int this_len;
864
865 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
866 memcpy(obj, subbuf->head[0].iov_base, this_len);
867 len -= this_len;
868 obj += this_len;
869 this_len = min_t(unsigned int, len, subbuf->page_len);
870 if (this_len)
871 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
872 len -= this_len;
873 obj += this_len;
874 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
875 memcpy(obj, subbuf->tail[0].iov_base, this_len);
876}
877
878/* obj is assumed to point to allocated memory of size at least len: */
879int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
880{
881 struct xdr_buf subbuf;
882 int status;
883
884 status = xdr_buf_subsegment(buf, &subbuf, base, len);
885 if (status != 0)
886 return status;
887 __read_bytes_from_xdr_buf(&subbuf, obj, len);
888 return 0;
889}
890EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
891
892static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
893{
894 unsigned int this_len;
895
896 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
897 memcpy(subbuf->head[0].iov_base, obj, this_len);
898 len -= this_len;
899 obj += this_len;
900 this_len = min_t(unsigned int, len, subbuf->page_len);
901 if (this_len)
902 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
903 len -= this_len;
904 obj += this_len;
905 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
906 memcpy(subbuf->tail[0].iov_base, obj, this_len);
907}
908
909/* obj is assumed to point to allocated memory of size at least len: */
910int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
911{
912 struct xdr_buf subbuf;
913 int status;
914
915 status = xdr_buf_subsegment(buf, &subbuf, base, len);
916 if (status != 0)
917 return status;
918 __write_bytes_to_xdr_buf(&subbuf, obj, len);
919 return 0;
920}
921EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
922
923int
924xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
925{
926 __be32 raw;
927 int status;
928
929 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
930 if (status)
931 return status;
932 *obj = be32_to_cpu(raw);
933 return 0;
934}
935EXPORT_SYMBOL_GPL(xdr_decode_word);
936
937int
938xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
939{
940 __be32 raw = cpu_to_be32(obj);
941
942 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
943}
944EXPORT_SYMBOL_GPL(xdr_encode_word);
945
946/* If the netobj starting offset bytes from the start of xdr_buf is contained
947 * entirely in the head or the tail, set object to point to it; otherwise
948 * try to find space for it at the end of the tail, copy it there, and
949 * set obj to point to it. */
950int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
951{
952 struct xdr_buf subbuf;
953
954 if (xdr_decode_word(buf, offset, &obj->len))
955 return -EFAULT;
956 if (xdr_buf_subsegment(buf, &subbuf, offset + 4, obj->len))
957 return -EFAULT;
958
959 /* Is the obj contained entirely in the head? */
960 obj->data = subbuf.head[0].iov_base;
961 if (subbuf.head[0].iov_len == obj->len)
962 return 0;
963 /* ..or is the obj contained entirely in the tail? */
964 obj->data = subbuf.tail[0].iov_base;
965 if (subbuf.tail[0].iov_len == obj->len)
966 return 0;
967
968 /* use end of tail as storage for obj:
969 * (We don't copy to the beginning because then we'd have
970 * to worry about doing a potentially overlapping copy.
971 * This assumes the object is at most half the length of the
972 * tail.) */
973 if (obj->len > buf->buflen - buf->len)
974 return -ENOMEM;
975 if (buf->tail[0].iov_len != 0)
976 obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
977 else
978 obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
979 __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
980 return 0;
981}
982EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
983
984/* Returns 0 on success, or else a negative error code. */
985static int
986xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
987 struct xdr_array2_desc *desc, int encode)
988{
989 char *elem = NULL, *c;
990 unsigned int copied = 0, todo, avail_here;
991 struct page **ppages = NULL;
992 int err;
993
994 if (encode) {
995 if (xdr_encode_word(buf, base, desc->array_len) != 0)
996 return -EINVAL;
997 } else {
998 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
999 desc->array_len > desc->array_maxlen ||
1000 (unsigned long) base + 4 + desc->array_len *
1001 desc->elem_size > buf->len)
1002 return -EINVAL;
1003 }
1004 base += 4;
1005
1006 if (!desc->xcode)
1007 return 0;
1008
1009 todo = desc->array_len * desc->elem_size;
1010
1011 /* process head */
1012 if (todo && base < buf->head->iov_len) {
1013 c = buf->head->iov_base + base;
1014 avail_here = min_t(unsigned int, todo,
1015 buf->head->iov_len - base);
1016 todo -= avail_here;
1017
1018 while (avail_here >= desc->elem_size) {
1019 err = desc->xcode(desc, c);
1020 if (err)
1021 goto out;
1022 c += desc->elem_size;
1023 avail_here -= desc->elem_size;
1024 }
1025 if (avail_here) {
1026 if (!elem) {
1027 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1028 err = -ENOMEM;
1029 if (!elem)
1030 goto out;
1031 }
1032 if (encode) {
1033 err = desc->xcode(desc, elem);
1034 if (err)
1035 goto out;
1036 memcpy(c, elem, avail_here);
1037 } else
1038 memcpy(elem, c, avail_here);
1039 copied = avail_here;
1040 }
1041 base = buf->head->iov_len; /* align to start of pages */
1042 }
1043
1044 /* process pages array */
1045 base -= buf->head->iov_len;
1046 if (todo && base < buf->page_len) {
1047 unsigned int avail_page;
1048
1049 avail_here = min(todo, buf->page_len - base);
1050 todo -= avail_here;
1051
1052 base += buf->page_base;
1053 ppages = buf->pages + (base >> PAGE_CACHE_SHIFT);
1054 base &= ~PAGE_CACHE_MASK;
1055 avail_page = min_t(unsigned int, PAGE_CACHE_SIZE - base,
1056 avail_here);
1057 c = kmap(*ppages) + base;
1058
1059 while (avail_here) {
1060 avail_here -= avail_page;
1061 if (copied || avail_page < desc->elem_size) {
1062 unsigned int l = min(avail_page,
1063 desc->elem_size - copied);
1064 if (!elem) {
1065 elem = kmalloc(desc->elem_size,
1066 GFP_KERNEL);
1067 err = -ENOMEM;
1068 if (!elem)
1069 goto out;
1070 }
1071 if (encode) {
1072 if (!copied) {
1073 err = desc->xcode(desc, elem);
1074 if (err)
1075 goto out;
1076 }
1077 memcpy(c, elem + copied, l);
1078 copied += l;
1079 if (copied == desc->elem_size)
1080 copied = 0;
1081 } else {
1082 memcpy(elem + copied, c, l);
1083 copied += l;
1084 if (copied == desc->elem_size) {
1085 err = desc->xcode(desc, elem);
1086 if (err)
1087 goto out;
1088 copied = 0;
1089 }
1090 }
1091 avail_page -= l;
1092 c += l;
1093 }
1094 while (avail_page >= desc->elem_size) {
1095 err = desc->xcode(desc, c);
1096 if (err)
1097 goto out;
1098 c += desc->elem_size;
1099 avail_page -= desc->elem_size;
1100 }
1101 if (avail_page) {
1102 unsigned int l = min(avail_page,
1103 desc->elem_size - copied);
1104 if (!elem) {
1105 elem = kmalloc(desc->elem_size,
1106 GFP_KERNEL);
1107 err = -ENOMEM;
1108 if (!elem)
1109 goto out;
1110 }
1111 if (encode) {
1112 if (!copied) {
1113 err = desc->xcode(desc, elem);
1114 if (err)
1115 goto out;
1116 }
1117 memcpy(c, elem + copied, l);
1118 copied += l;
1119 if (copied == desc->elem_size)
1120 copied = 0;
1121 } else {
1122 memcpy(elem + copied, c, l);
1123 copied += l;
1124 if (copied == desc->elem_size) {
1125 err = desc->xcode(desc, elem);
1126 if (err)
1127 goto out;
1128 copied = 0;
1129 }
1130 }
1131 }
1132 if (avail_here) {
1133 kunmap(*ppages);
1134 ppages++;
1135 c = kmap(*ppages);
1136 }
1137
1138 avail_page = min(avail_here,
1139 (unsigned int) PAGE_CACHE_SIZE);
1140 }
1141 base = buf->page_len; /* align to start of tail */
1142 }
1143
1144 /* process tail */
1145 base -= buf->page_len;
1146 if (todo) {
1147 c = buf->tail->iov_base + base;
1148 if (copied) {
1149 unsigned int l = desc->elem_size - copied;
1150
1151 if (encode)
1152 memcpy(c, elem + copied, l);
1153 else {
1154 memcpy(elem + copied, c, l);
1155 err = desc->xcode(desc, elem);
1156 if (err)
1157 goto out;
1158 }
1159 todo -= l;
1160 c += l;
1161 }
1162 while (todo) {
1163 err = desc->xcode(desc, c);
1164 if (err)
1165 goto out;
1166 c += desc->elem_size;
1167 todo -= desc->elem_size;
1168 }
1169 }
1170 err = 0;
1171
1172out:
1173 kfree(elem);
1174 if (ppages)
1175 kunmap(*ppages);
1176 return err;
1177}
1178
1179int
1180xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
1181 struct xdr_array2_desc *desc)
1182{
1183 if (base >= buf->len)
1184 return -EINVAL;
1185
1186 return xdr_xcode_array2(buf, base, desc, 0);
1187}
1188EXPORT_SYMBOL_GPL(xdr_decode_array2);
1189
1190int
1191xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
1192 struct xdr_array2_desc *desc)
1193{
1194 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
1195 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
1196 return -EINVAL;
1197
1198 return xdr_xcode_array2(buf, base, desc, 1);
1199}
1200EXPORT_SYMBOL_GPL(xdr_encode_array2);
1201
1202int
1203xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
1204 int (*actor)(struct scatterlist *, void *), void *data)
1205{
1206 int i, ret = 0;
1207 unsigned int page_len, thislen, page_offset;
1208 struct scatterlist sg[1];
1209
1210 sg_init_table(sg, 1);
1211
1212 if (offset >= buf->head[0].iov_len) {
1213 offset -= buf->head[0].iov_len;
1214 } else {
1215 thislen = buf->head[0].iov_len - offset;
1216 if (thislen > len)
1217 thislen = len;
1218 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
1219 ret = actor(sg, data);
1220 if (ret)
1221 goto out;
1222 offset = 0;
1223 len -= thislen;
1224 }
1225 if (len == 0)
1226 goto out;
1227
1228 if (offset >= buf->page_len) {
1229 offset -= buf->page_len;
1230 } else {
1231 page_len = buf->page_len - offset;
1232 if (page_len > len)
1233 page_len = len;
1234 len -= page_len;
1235 page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
1236 i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
1237 thislen = PAGE_CACHE_SIZE - page_offset;
1238 do {
1239 if (thislen > page_len)
1240 thislen = page_len;
1241 sg_set_page(sg, buf->pages[i], thislen, page_offset);
1242 ret = actor(sg, data);
1243 if (ret)
1244 goto out;
1245 page_len -= thislen;
1246 i++;
1247 page_offset = 0;
1248 thislen = PAGE_CACHE_SIZE;
1249 } while (page_len != 0);
1250 offset = 0;
1251 }
1252 if (len == 0)
1253 goto out;
1254 if (offset < buf->tail[0].iov_len) {
1255 thislen = buf->tail[0].iov_len - offset;
1256 if (thislen > len)
1257 thislen = len;
1258 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
1259 ret = actor(sg, data);
1260 len -= thislen;
1261 }
1262 if (len != 0)
1263 ret = -EINVAL;
1264out:
1265 return ret;
1266}
1267EXPORT_SYMBOL_GPL(xdr_process_buf);
1268