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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/net/sunrpc/xdr.c
4 *
5 * Generic XDR support.
6 *
7 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
8 */
9
10#include <linux/module.h>
11#include <linux/slab.h>
12#include <linux/types.h>
13#include <linux/string.h>
14#include <linux/kernel.h>
15#include <linux/pagemap.h>
16#include <linux/errno.h>
17#include <linux/sunrpc/xdr.h>
18#include <linux/sunrpc/msg_prot.h>
19#include <linux/bvec.h>
20#include <trace/events/sunrpc.h>
21
22/*
23 * XDR functions for basic NFS types
24 */
25__be32 *
26xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
27{
28 unsigned int quadlen = XDR_QUADLEN(obj->len);
29
30 p[quadlen] = 0; /* zero trailing bytes */
31 *p++ = cpu_to_be32(obj->len);
32 memcpy(p, obj->data, obj->len);
33 return p + XDR_QUADLEN(obj->len);
34}
35EXPORT_SYMBOL_GPL(xdr_encode_netobj);
36
37__be32 *
38xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
39{
40 unsigned int len;
41
42 if ((len = be32_to_cpu(*p++)) > XDR_MAX_NETOBJ)
43 return NULL;
44 obj->len = len;
45 obj->data = (u8 *) p;
46 return p + XDR_QUADLEN(len);
47}
48EXPORT_SYMBOL_GPL(xdr_decode_netobj);
49
50/**
51 * xdr_encode_opaque_fixed - Encode fixed length opaque data
52 * @p: pointer to current position in XDR buffer.
53 * @ptr: pointer to data to encode (or NULL)
54 * @nbytes: size of data.
55 *
56 * Copy the array of data of length nbytes at ptr to the XDR buffer
57 * at position p, then align to the next 32-bit boundary by padding
58 * with zero bytes (see RFC1832).
59 * Note: if ptr is NULL, only the padding is performed.
60 *
61 * Returns the updated current XDR buffer position
62 *
63 */
64__be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
65{
66 if (likely(nbytes != 0)) {
67 unsigned int quadlen = XDR_QUADLEN(nbytes);
68 unsigned int padding = (quadlen << 2) - nbytes;
69
70 if (ptr != NULL)
71 memcpy(p, ptr, nbytes);
72 if (padding != 0)
73 memset((char *)p + nbytes, 0, padding);
74 p += quadlen;
75 }
76 return p;
77}
78EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed);
79
80/**
81 * xdr_encode_opaque - Encode variable length opaque data
82 * @p: pointer to current position in XDR buffer.
83 * @ptr: pointer to data to encode (or NULL)
84 * @nbytes: size of data.
85 *
86 * Returns the updated current XDR buffer position
87 */
88__be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
89{
90 *p++ = cpu_to_be32(nbytes);
91 return xdr_encode_opaque_fixed(p, ptr, nbytes);
92}
93EXPORT_SYMBOL_GPL(xdr_encode_opaque);
94
95__be32 *
96xdr_encode_string(__be32 *p, const char *string)
97{
98 return xdr_encode_array(p, string, strlen(string));
99}
100EXPORT_SYMBOL_GPL(xdr_encode_string);
101
102__be32 *
103xdr_decode_string_inplace(__be32 *p, char **sp,
104 unsigned int *lenp, unsigned int maxlen)
105{
106 u32 len;
107
108 len = be32_to_cpu(*p++);
109 if (len > maxlen)
110 return NULL;
111 *lenp = len;
112 *sp = (char *) p;
113 return p + XDR_QUADLEN(len);
114}
115EXPORT_SYMBOL_GPL(xdr_decode_string_inplace);
116
117/**
118 * xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
119 * @buf: XDR buffer where string resides
120 * @len: length of string, in bytes
121 *
122 */
123void
124xdr_terminate_string(struct xdr_buf *buf, const u32 len)
125{
126 char *kaddr;
127
128 kaddr = kmap_atomic(buf->pages[0]);
129 kaddr[buf->page_base + len] = '\0';
130 kunmap_atomic(kaddr);
131}
132EXPORT_SYMBOL_GPL(xdr_terminate_string);
133
134size_t
135xdr_buf_pagecount(struct xdr_buf *buf)
136{
137 if (!buf->page_len)
138 return 0;
139 return (buf->page_base + buf->page_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
140}
141
142int
143xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp)
144{
145 size_t i, n = xdr_buf_pagecount(buf);
146
147 if (n != 0 && buf->bvec == NULL) {
148 buf->bvec = kmalloc_array(n, sizeof(buf->bvec[0]), gfp);
149 if (!buf->bvec)
150 return -ENOMEM;
151 for (i = 0; i < n; i++) {
152 buf->bvec[i].bv_page = buf->pages[i];
153 buf->bvec[i].bv_len = PAGE_SIZE;
154 buf->bvec[i].bv_offset = 0;
155 }
156 }
157 return 0;
158}
159
160void
161xdr_free_bvec(struct xdr_buf *buf)
162{
163 kfree(buf->bvec);
164 buf->bvec = NULL;
165}
166
167/**
168 * xdr_inline_pages - Prepare receive buffer for a large reply
169 * @xdr: xdr_buf into which reply will be placed
170 * @offset: expected offset where data payload will start, in bytes
171 * @pages: vector of struct page pointers
172 * @base: offset in first page where receive should start, in bytes
173 * @len: expected size of the upper layer data payload, in bytes
174 *
175 */
176void
177xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
178 struct page **pages, unsigned int base, unsigned int len)
179{
180 struct kvec *head = xdr->head;
181 struct kvec *tail = xdr->tail;
182 char *buf = (char *)head->iov_base;
183 unsigned int buflen = head->iov_len;
184
185 head->iov_len = offset;
186
187 xdr->pages = pages;
188 xdr->page_base = base;
189 xdr->page_len = len;
190
191 tail->iov_base = buf + offset;
192 tail->iov_len = buflen - offset;
193 if ((xdr->page_len & 3) == 0)
194 tail->iov_len -= sizeof(__be32);
195
196 xdr->buflen += len;
197}
198EXPORT_SYMBOL_GPL(xdr_inline_pages);
199
200/*
201 * Helper routines for doing 'memmove' like operations on a struct xdr_buf
202 */
203
204/**
205 * _shift_data_right_pages
206 * @pages: vector of pages containing both the source and dest memory area.
207 * @pgto_base: page vector address of destination
208 * @pgfrom_base: page vector address of source
209 * @len: number of bytes to copy
210 *
211 * Note: the addresses pgto_base and pgfrom_base are both calculated in
212 * the same way:
213 * if a memory area starts at byte 'base' in page 'pages[i]',
214 * then its address is given as (i << PAGE_SHIFT) + base
215 * Also note: pgfrom_base must be < pgto_base, but the memory areas
216 * they point to may overlap.
217 */
218static void
219_shift_data_right_pages(struct page **pages, size_t pgto_base,
220 size_t pgfrom_base, size_t len)
221{
222 struct page **pgfrom, **pgto;
223 char *vfrom, *vto;
224 size_t copy;
225
226 BUG_ON(pgto_base <= pgfrom_base);
227
228 pgto_base += len;
229 pgfrom_base += len;
230
231 pgto = pages + (pgto_base >> PAGE_SHIFT);
232 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
233
234 pgto_base &= ~PAGE_MASK;
235 pgfrom_base &= ~PAGE_MASK;
236
237 do {
238 /* Are any pointers crossing a page boundary? */
239 if (pgto_base == 0) {
240 pgto_base = PAGE_SIZE;
241 pgto--;
242 }
243 if (pgfrom_base == 0) {
244 pgfrom_base = PAGE_SIZE;
245 pgfrom--;
246 }
247
248 copy = len;
249 if (copy > pgto_base)
250 copy = pgto_base;
251 if (copy > pgfrom_base)
252 copy = pgfrom_base;
253 pgto_base -= copy;
254 pgfrom_base -= copy;
255
256 vto = kmap_atomic(*pgto);
257 if (*pgto != *pgfrom) {
258 vfrom = kmap_atomic(*pgfrom);
259 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
260 kunmap_atomic(vfrom);
261 } else
262 memmove(vto + pgto_base, vto + pgfrom_base, copy);
263 flush_dcache_page(*pgto);
264 kunmap_atomic(vto);
265
266 } while ((len -= copy) != 0);
267}
268
269/**
270 * _copy_to_pages
271 * @pages: array of pages
272 * @pgbase: page vector address of destination
273 * @p: pointer to source data
274 * @len: length
275 *
276 * Copies data from an arbitrary memory location into an array of pages
277 * The copy is assumed to be non-overlapping.
278 */
279static void
280_copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
281{
282 struct page **pgto;
283 char *vto;
284 size_t copy;
285
286 pgto = pages + (pgbase >> PAGE_SHIFT);
287 pgbase &= ~PAGE_MASK;
288
289 for (;;) {
290 copy = PAGE_SIZE - pgbase;
291 if (copy > len)
292 copy = len;
293
294 vto = kmap_atomic(*pgto);
295 memcpy(vto + pgbase, p, copy);
296 kunmap_atomic(vto);
297
298 len -= copy;
299 if (len == 0)
300 break;
301
302 pgbase += copy;
303 if (pgbase == PAGE_SIZE) {
304 flush_dcache_page(*pgto);
305 pgbase = 0;
306 pgto++;
307 }
308 p += copy;
309 }
310 flush_dcache_page(*pgto);
311}
312
313/**
314 * _copy_from_pages
315 * @p: pointer to destination
316 * @pages: array of pages
317 * @pgbase: offset of source data
318 * @len: length
319 *
320 * Copies data into an arbitrary memory location from an array of pages
321 * The copy is assumed to be non-overlapping.
322 */
323void
324_copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
325{
326 struct page **pgfrom;
327 char *vfrom;
328 size_t copy;
329
330 pgfrom = pages + (pgbase >> PAGE_SHIFT);
331 pgbase &= ~PAGE_MASK;
332
333 do {
334 copy = PAGE_SIZE - pgbase;
335 if (copy > len)
336 copy = len;
337
338 vfrom = kmap_atomic(*pgfrom);
339 memcpy(p, vfrom + pgbase, copy);
340 kunmap_atomic(vfrom);
341
342 pgbase += copy;
343 if (pgbase == PAGE_SIZE) {
344 pgbase = 0;
345 pgfrom++;
346 }
347 p += copy;
348
349 } while ((len -= copy) != 0);
350}
351EXPORT_SYMBOL_GPL(_copy_from_pages);
352
353/**
354 * xdr_shrink_bufhead
355 * @buf: xdr_buf
356 * @len: bytes to remove from buf->head[0]
357 *
358 * Shrinks XDR buffer's header kvec buf->head[0] by
359 * 'len' bytes. The extra data is not lost, but is instead
360 * moved into the inlined pages and/or the tail.
361 */
362static unsigned int
363xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
364{
365 struct kvec *head, *tail;
366 size_t copy, offs;
367 unsigned int pglen = buf->page_len;
368 unsigned int result;
369
370 result = 0;
371 tail = buf->tail;
372 head = buf->head;
373
374 WARN_ON_ONCE(len > head->iov_len);
375 if (len > head->iov_len)
376 len = head->iov_len;
377
378 /* Shift the tail first */
379 if (tail->iov_len != 0) {
380 if (tail->iov_len > len) {
381 copy = tail->iov_len - len;
382 memmove((char *)tail->iov_base + len,
383 tail->iov_base, copy);
384 result += copy;
385 }
386 /* Copy from the inlined pages into the tail */
387 copy = len;
388 if (copy > pglen)
389 copy = pglen;
390 offs = len - copy;
391 if (offs >= tail->iov_len)
392 copy = 0;
393 else if (copy > tail->iov_len - offs)
394 copy = tail->iov_len - offs;
395 if (copy != 0) {
396 _copy_from_pages((char *)tail->iov_base + offs,
397 buf->pages,
398 buf->page_base + pglen + offs - len,
399 copy);
400 result += copy;
401 }
402 /* Do we also need to copy data from the head into the tail ? */
403 if (len > pglen) {
404 offs = copy = len - pglen;
405 if (copy > tail->iov_len)
406 copy = tail->iov_len;
407 memcpy(tail->iov_base,
408 (char *)head->iov_base +
409 head->iov_len - offs,
410 copy);
411 result += copy;
412 }
413 }
414 /* Now handle pages */
415 if (pglen != 0) {
416 if (pglen > len)
417 _shift_data_right_pages(buf->pages,
418 buf->page_base + len,
419 buf->page_base,
420 pglen - len);
421 copy = len;
422 if (len > pglen)
423 copy = pglen;
424 _copy_to_pages(buf->pages, buf->page_base,
425 (char *)head->iov_base + head->iov_len - len,
426 copy);
427 result += copy;
428 }
429 head->iov_len -= len;
430 buf->buflen -= len;
431 /* Have we truncated the message? */
432 if (buf->len > buf->buflen)
433 buf->len = buf->buflen;
434
435 return result;
436}
437
438/**
439 * xdr_shrink_pagelen
440 * @buf: xdr_buf
441 * @len: bytes to remove from buf->pages
442 *
443 * Shrinks XDR buffer's page array buf->pages by
444 * 'len' bytes. The extra data is not lost, but is instead
445 * moved into the tail.
446 */
447static unsigned int
448xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
449{
450 struct kvec *tail;
451 size_t copy;
452 unsigned int pglen = buf->page_len;
453 unsigned int tailbuf_len;
454 unsigned int result;
455
456 result = 0;
457 tail = buf->tail;
458 BUG_ON (len > pglen);
459
460 tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
461
462 /* Shift the tail first */
463 if (tailbuf_len != 0) {
464 unsigned int free_space = tailbuf_len - tail->iov_len;
465
466 if (len < free_space)
467 free_space = len;
468 tail->iov_len += free_space;
469
470 copy = len;
471 if (tail->iov_len > len) {
472 char *p = (char *)tail->iov_base + len;
473 memmove(p, tail->iov_base, tail->iov_len - len);
474 result += tail->iov_len - len;
475 } else
476 copy = tail->iov_len;
477 /* Copy from the inlined pages into the tail */
478 _copy_from_pages((char *)tail->iov_base,
479 buf->pages, buf->page_base + pglen - len,
480 copy);
481 result += copy;
482 }
483 buf->page_len -= len;
484 buf->buflen -= len;
485 /* Have we truncated the message? */
486 if (buf->len > buf->buflen)
487 buf->len = buf->buflen;
488
489 return result;
490}
491
492void
493xdr_shift_buf(struct xdr_buf *buf, size_t len)
494{
495 xdr_shrink_bufhead(buf, len);
496}
497EXPORT_SYMBOL_GPL(xdr_shift_buf);
498
499/**
500 * xdr_stream_pos - Return the current offset from the start of the xdr_stream
501 * @xdr: pointer to struct xdr_stream
502 */
503unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
504{
505 return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
506}
507EXPORT_SYMBOL_GPL(xdr_stream_pos);
508
509/**
510 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
511 * @xdr: pointer to xdr_stream struct
512 * @buf: pointer to XDR buffer in which to encode data
513 * @p: current pointer inside XDR buffer
514 * @rqst: pointer to controlling rpc_rqst, for debugging
515 *
516 * Note: at the moment the RPC client only passes the length of our
517 * scratch buffer in the xdr_buf's header kvec. Previously this
518 * meant we needed to call xdr_adjust_iovec() after encoding the
519 * data. With the new scheme, the xdr_stream manages the details
520 * of the buffer length, and takes care of adjusting the kvec
521 * length for us.
522 */
523void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
524 struct rpc_rqst *rqst)
525{
526 struct kvec *iov = buf->head;
527 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
528
529 xdr_set_scratch_buffer(xdr, NULL, 0);
530 BUG_ON(scratch_len < 0);
531 xdr->buf = buf;
532 xdr->iov = iov;
533 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
534 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
535 BUG_ON(iov->iov_len > scratch_len);
536
537 if (p != xdr->p && p != NULL) {
538 size_t len;
539
540 BUG_ON(p < xdr->p || p > xdr->end);
541 len = (char *)p - (char *)xdr->p;
542 xdr->p = p;
543 buf->len += len;
544 iov->iov_len += len;
545 }
546 xdr->rqst = rqst;
547}
548EXPORT_SYMBOL_GPL(xdr_init_encode);
549
550/**
551 * xdr_commit_encode - Ensure all data is written to buffer
552 * @xdr: pointer to xdr_stream
553 *
554 * We handle encoding across page boundaries by giving the caller a
555 * temporary location to write to, then later copying the data into
556 * place; xdr_commit_encode does that copying.
557 *
558 * Normally the caller doesn't need to call this directly, as the
559 * following xdr_reserve_space will do it. But an explicit call may be
560 * required at the end of encoding, or any other time when the xdr_buf
561 * data might be read.
562 */
563inline void xdr_commit_encode(struct xdr_stream *xdr)
564{
565 int shift = xdr->scratch.iov_len;
566 void *page;
567
568 if (shift == 0)
569 return;
570 page = page_address(*xdr->page_ptr);
571 memcpy(xdr->scratch.iov_base, page, shift);
572 memmove(page, page + shift, (void *)xdr->p - page);
573 xdr->scratch.iov_len = 0;
574}
575EXPORT_SYMBOL_GPL(xdr_commit_encode);
576
577static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
578 size_t nbytes)
579{
580 __be32 *p;
581 int space_left;
582 int frag1bytes, frag2bytes;
583
584 if (nbytes > PAGE_SIZE)
585 goto out_overflow; /* Bigger buffers require special handling */
586 if (xdr->buf->len + nbytes > xdr->buf->buflen)
587 goto out_overflow; /* Sorry, we're totally out of space */
588 frag1bytes = (xdr->end - xdr->p) << 2;
589 frag2bytes = nbytes - frag1bytes;
590 if (xdr->iov)
591 xdr->iov->iov_len += frag1bytes;
592 else
593 xdr->buf->page_len += frag1bytes;
594 xdr->page_ptr++;
595 xdr->iov = NULL;
596 /*
597 * If the last encode didn't end exactly on a page boundary, the
598 * next one will straddle boundaries. Encode into the next
599 * page, then copy it back later in xdr_commit_encode. We use
600 * the "scratch" iov to track any temporarily unused fragment of
601 * space at the end of the previous buffer:
602 */
603 xdr->scratch.iov_base = xdr->p;
604 xdr->scratch.iov_len = frag1bytes;
605 p = page_address(*xdr->page_ptr);
606 /*
607 * Note this is where the next encode will start after we've
608 * shifted this one back:
609 */
610 xdr->p = (void *)p + frag2bytes;
611 space_left = xdr->buf->buflen - xdr->buf->len;
612 xdr->end = (void *)p + min_t(int, space_left, PAGE_SIZE);
613 xdr->buf->page_len += frag2bytes;
614 xdr->buf->len += nbytes;
615 return p;
616out_overflow:
617 trace_rpc_xdr_overflow(xdr, nbytes);
618 return NULL;
619}
620
621/**
622 * xdr_reserve_space - Reserve buffer space for sending
623 * @xdr: pointer to xdr_stream
624 * @nbytes: number of bytes to reserve
625 *
626 * Checks that we have enough buffer space to encode 'nbytes' more
627 * bytes of data. If so, update the total xdr_buf length, and
628 * adjust the length of the current kvec.
629 */
630__be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
631{
632 __be32 *p = xdr->p;
633 __be32 *q;
634
635 xdr_commit_encode(xdr);
636 /* align nbytes on the next 32-bit boundary */
637 nbytes += 3;
638 nbytes &= ~3;
639 q = p + (nbytes >> 2);
640 if (unlikely(q > xdr->end || q < p))
641 return xdr_get_next_encode_buffer(xdr, nbytes);
642 xdr->p = q;
643 if (xdr->iov)
644 xdr->iov->iov_len += nbytes;
645 else
646 xdr->buf->page_len += nbytes;
647 xdr->buf->len += nbytes;
648 return p;
649}
650EXPORT_SYMBOL_GPL(xdr_reserve_space);
651
652/**
653 * xdr_truncate_encode - truncate an encode buffer
654 * @xdr: pointer to xdr_stream
655 * @len: new length of buffer
656 *
657 * Truncates the xdr stream, so that xdr->buf->len == len,
658 * and xdr->p points at offset len from the start of the buffer, and
659 * head, tail, and page lengths are adjusted to correspond.
660 *
661 * If this means moving xdr->p to a different buffer, we assume that
662 * that the end pointer should be set to the end of the current page,
663 * except in the case of the head buffer when we assume the head
664 * buffer's current length represents the end of the available buffer.
665 *
666 * This is *not* safe to use on a buffer that already has inlined page
667 * cache pages (as in a zero-copy server read reply), except for the
668 * simple case of truncating from one position in the tail to another.
669 *
670 */
671void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
672{
673 struct xdr_buf *buf = xdr->buf;
674 struct kvec *head = buf->head;
675 struct kvec *tail = buf->tail;
676 int fraglen;
677 int new;
678
679 if (len > buf->len) {
680 WARN_ON_ONCE(1);
681 return;
682 }
683 xdr_commit_encode(xdr);
684
685 fraglen = min_t(int, buf->len - len, tail->iov_len);
686 tail->iov_len -= fraglen;
687 buf->len -= fraglen;
688 if (tail->iov_len) {
689 xdr->p = tail->iov_base + tail->iov_len;
690 WARN_ON_ONCE(!xdr->end);
691 WARN_ON_ONCE(!xdr->iov);
692 return;
693 }
694 WARN_ON_ONCE(fraglen);
695 fraglen = min_t(int, buf->len - len, buf->page_len);
696 buf->page_len -= fraglen;
697 buf->len -= fraglen;
698
699 new = buf->page_base + buf->page_len;
700
701 xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
702
703 if (buf->page_len) {
704 xdr->p = page_address(*xdr->page_ptr);
705 xdr->end = (void *)xdr->p + PAGE_SIZE;
706 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
707 WARN_ON_ONCE(xdr->iov);
708 return;
709 }
710 if (fraglen)
711 xdr->end = head->iov_base + head->iov_len;
712 /* (otherwise assume xdr->end is already set) */
713 xdr->page_ptr--;
714 head->iov_len = len;
715 buf->len = len;
716 xdr->p = head->iov_base + head->iov_len;
717 xdr->iov = buf->head;
718}
719EXPORT_SYMBOL(xdr_truncate_encode);
720
721/**
722 * xdr_restrict_buflen - decrease available buffer space
723 * @xdr: pointer to xdr_stream
724 * @newbuflen: new maximum number of bytes available
725 *
726 * Adjust our idea of how much space is available in the buffer.
727 * If we've already used too much space in the buffer, returns -1.
728 * If the available space is already smaller than newbuflen, returns 0
729 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
730 * and ensures xdr->end is set at most offset newbuflen from the start
731 * of the buffer.
732 */
733int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
734{
735 struct xdr_buf *buf = xdr->buf;
736 int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
737 int end_offset = buf->len + left_in_this_buf;
738
739 if (newbuflen < 0 || newbuflen < buf->len)
740 return -1;
741 if (newbuflen > buf->buflen)
742 return 0;
743 if (newbuflen < end_offset)
744 xdr->end = (void *)xdr->end + newbuflen - end_offset;
745 buf->buflen = newbuflen;
746 return 0;
747}
748EXPORT_SYMBOL(xdr_restrict_buflen);
749
750/**
751 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
752 * @xdr: pointer to xdr_stream
753 * @pages: list of pages
754 * @base: offset of first byte
755 * @len: length of data in bytes
756 *
757 */
758void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
759 unsigned int len)
760{
761 struct xdr_buf *buf = xdr->buf;
762 struct kvec *iov = buf->tail;
763 buf->pages = pages;
764 buf->page_base = base;
765 buf->page_len = len;
766
767 iov->iov_base = (char *)xdr->p;
768 iov->iov_len = 0;
769 xdr->iov = iov;
770
771 if (len & 3) {
772 unsigned int pad = 4 - (len & 3);
773
774 BUG_ON(xdr->p >= xdr->end);
775 iov->iov_base = (char *)xdr->p + (len & 3);
776 iov->iov_len += pad;
777 len += pad;
778 *xdr->p++ = 0;
779 }
780 buf->buflen += len;
781 buf->len += len;
782}
783EXPORT_SYMBOL_GPL(xdr_write_pages);
784
785static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
786 unsigned int len)
787{
788 if (len > iov->iov_len)
789 len = iov->iov_len;
790 xdr->p = (__be32*)iov->iov_base;
791 xdr->end = (__be32*)(iov->iov_base + len);
792 xdr->iov = iov;
793 xdr->page_ptr = NULL;
794}
795
796static int xdr_set_page_base(struct xdr_stream *xdr,
797 unsigned int base, unsigned int len)
798{
799 unsigned int pgnr;
800 unsigned int maxlen;
801 unsigned int pgoff;
802 unsigned int pgend;
803 void *kaddr;
804
805 maxlen = xdr->buf->page_len;
806 if (base >= maxlen)
807 return -EINVAL;
808 maxlen -= base;
809 if (len > maxlen)
810 len = maxlen;
811
812 base += xdr->buf->page_base;
813
814 pgnr = base >> PAGE_SHIFT;
815 xdr->page_ptr = &xdr->buf->pages[pgnr];
816 kaddr = page_address(*xdr->page_ptr);
817
818 pgoff = base & ~PAGE_MASK;
819 xdr->p = (__be32*)(kaddr + pgoff);
820
821 pgend = pgoff + len;
822 if (pgend > PAGE_SIZE)
823 pgend = PAGE_SIZE;
824 xdr->end = (__be32*)(kaddr + pgend);
825 xdr->iov = NULL;
826 return 0;
827}
828
829static void xdr_set_next_page(struct xdr_stream *xdr)
830{
831 unsigned int newbase;
832
833 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
834 newbase -= xdr->buf->page_base;
835
836 if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
837 xdr_set_iov(xdr, xdr->buf->tail, xdr->nwords << 2);
838}
839
840static bool xdr_set_next_buffer(struct xdr_stream *xdr)
841{
842 if (xdr->page_ptr != NULL)
843 xdr_set_next_page(xdr);
844 else if (xdr->iov == xdr->buf->head) {
845 if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
846 xdr_set_iov(xdr, xdr->buf->tail, xdr->nwords << 2);
847 }
848 return xdr->p != xdr->end;
849}
850
851/**
852 * xdr_init_decode - Initialize an xdr_stream for decoding data.
853 * @xdr: pointer to xdr_stream struct
854 * @buf: pointer to XDR buffer from which to decode data
855 * @p: current pointer inside XDR buffer
856 * @rqst: pointer to controlling rpc_rqst, for debugging
857 */
858void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
859 struct rpc_rqst *rqst)
860{
861 xdr->buf = buf;
862 xdr->scratch.iov_base = NULL;
863 xdr->scratch.iov_len = 0;
864 xdr->nwords = XDR_QUADLEN(buf->len);
865 if (buf->head[0].iov_len != 0)
866 xdr_set_iov(xdr, buf->head, buf->len);
867 else if (buf->page_len != 0)
868 xdr_set_page_base(xdr, 0, buf->len);
869 else
870 xdr_set_iov(xdr, buf->head, buf->len);
871 if (p != NULL && p > xdr->p && xdr->end >= p) {
872 xdr->nwords -= p - xdr->p;
873 xdr->p = p;
874 }
875 xdr->rqst = rqst;
876}
877EXPORT_SYMBOL_GPL(xdr_init_decode);
878
879/**
880 * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
881 * @xdr: pointer to xdr_stream struct
882 * @buf: pointer to XDR buffer from which to decode data
883 * @pages: list of pages to decode into
884 * @len: length in bytes of buffer in pages
885 */
886void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
887 struct page **pages, unsigned int len)
888{
889 memset(buf, 0, sizeof(*buf));
890 buf->pages = pages;
891 buf->page_len = len;
892 buf->buflen = len;
893 buf->len = len;
894 xdr_init_decode(xdr, buf, NULL, NULL);
895}
896EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
897
898static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
899{
900 unsigned int nwords = XDR_QUADLEN(nbytes);
901 __be32 *p = xdr->p;
902 __be32 *q = p + nwords;
903
904 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
905 return NULL;
906 xdr->p = q;
907 xdr->nwords -= nwords;
908 return p;
909}
910
911/**
912 * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
913 * @xdr: pointer to xdr_stream struct
914 * @buf: pointer to an empty buffer
915 * @buflen: size of 'buf'
916 *
917 * The scratch buffer is used when decoding from an array of pages.
918 * If an xdr_inline_decode() call spans across page boundaries, then
919 * we copy the data into the scratch buffer in order to allow linear
920 * access.
921 */
922void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
923{
924 xdr->scratch.iov_base = buf;
925 xdr->scratch.iov_len = buflen;
926}
927EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
928
929static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
930{
931 __be32 *p;
932 char *cpdest = xdr->scratch.iov_base;
933 size_t cplen = (char *)xdr->end - (char *)xdr->p;
934
935 if (nbytes > xdr->scratch.iov_len)
936 goto out_overflow;
937 p = __xdr_inline_decode(xdr, cplen);
938 if (p == NULL)
939 return NULL;
940 memcpy(cpdest, p, cplen);
941 if (!xdr_set_next_buffer(xdr))
942 goto out_overflow;
943 cpdest += cplen;
944 nbytes -= cplen;
945 p = __xdr_inline_decode(xdr, nbytes);
946 if (p == NULL)
947 return NULL;
948 memcpy(cpdest, p, nbytes);
949 return xdr->scratch.iov_base;
950out_overflow:
951 trace_rpc_xdr_overflow(xdr, nbytes);
952 return NULL;
953}
954
955/**
956 * xdr_inline_decode - Retrieve XDR data to decode
957 * @xdr: pointer to xdr_stream struct
958 * @nbytes: number of bytes of data to decode
959 *
960 * Check if the input buffer is long enough to enable us to decode
961 * 'nbytes' more bytes of data starting at the current position.
962 * If so return the current pointer, then update the current
963 * pointer position.
964 */
965__be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
966{
967 __be32 *p;
968
969 if (unlikely(nbytes == 0))
970 return xdr->p;
971 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
972 goto out_overflow;
973 p = __xdr_inline_decode(xdr, nbytes);
974 if (p != NULL)
975 return p;
976 return xdr_copy_to_scratch(xdr, nbytes);
977out_overflow:
978 trace_rpc_xdr_overflow(xdr, nbytes);
979 return NULL;
980}
981EXPORT_SYMBOL_GPL(xdr_inline_decode);
982
983static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
984{
985 struct xdr_buf *buf = xdr->buf;
986 struct kvec *iov;
987 unsigned int nwords = XDR_QUADLEN(len);
988 unsigned int cur = xdr_stream_pos(xdr);
989 unsigned int copied, offset;
990
991 if (xdr->nwords == 0)
992 return 0;
993
994 /* Realign pages to current pointer position */
995 iov = buf->head;
996 if (iov->iov_len > cur) {
997 offset = iov->iov_len - cur;
998 copied = xdr_shrink_bufhead(buf, offset);
999 trace_rpc_xdr_alignment(xdr, offset, copied);
1000 xdr->nwords = XDR_QUADLEN(buf->len - cur);
1001 }
1002
1003 if (nwords > xdr->nwords) {
1004 nwords = xdr->nwords;
1005 len = nwords << 2;
1006 }
1007 if (buf->page_len <= len)
1008 len = buf->page_len;
1009 else if (nwords < xdr->nwords) {
1010 /* Truncate page data and move it into the tail */
1011 offset = buf->page_len - len;
1012 copied = xdr_shrink_pagelen(buf, offset);
1013 trace_rpc_xdr_alignment(xdr, offset, copied);
1014 xdr->nwords = XDR_QUADLEN(buf->len - cur);
1015 }
1016 return len;
1017}
1018
1019/**
1020 * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
1021 * @xdr: pointer to xdr_stream struct
1022 * @len: number of bytes of page data
1023 *
1024 * Moves data beyond the current pointer position from the XDR head[] buffer
1025 * into the page list. Any data that lies beyond current position + "len"
1026 * bytes is moved into the XDR tail[].
1027 *
1028 * Returns the number of XDR encoded bytes now contained in the pages
1029 */
1030unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1031{
1032 struct xdr_buf *buf = xdr->buf;
1033 struct kvec *iov;
1034 unsigned int nwords;
1035 unsigned int end;
1036 unsigned int padding;
1037
1038 len = xdr_align_pages(xdr, len);
1039 if (len == 0)
1040 return 0;
1041 nwords = XDR_QUADLEN(len);
1042 padding = (nwords << 2) - len;
1043 xdr->iov = iov = buf->tail;
1044 /* Compute remaining message length. */
1045 end = ((xdr->nwords - nwords) << 2) + padding;
1046 if (end > iov->iov_len)
1047 end = iov->iov_len;
1048
1049 /*
1050 * Position current pointer at beginning of tail, and
1051 * set remaining message length.
1052 */
1053 xdr->p = (__be32 *)((char *)iov->iov_base + padding);
1054 xdr->end = (__be32 *)((char *)iov->iov_base + end);
1055 xdr->page_ptr = NULL;
1056 xdr->nwords = XDR_QUADLEN(end - padding);
1057 return len;
1058}
1059EXPORT_SYMBOL_GPL(xdr_read_pages);
1060
1061/**
1062 * xdr_enter_page - decode data from the XDR page
1063 * @xdr: pointer to xdr_stream struct
1064 * @len: number of bytes of page data
1065 *
1066 * Moves data beyond the current pointer position from the XDR head[] buffer
1067 * into the page list. Any data that lies beyond current position + "len"
1068 * bytes is moved into the XDR tail[]. The current pointer is then
1069 * repositioned at the beginning of the first XDR page.
1070 */
1071void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
1072{
1073 len = xdr_align_pages(xdr, len);
1074 /*
1075 * Position current pointer at beginning of tail, and
1076 * set remaining message length.
1077 */
1078 if (len != 0)
1079 xdr_set_page_base(xdr, 0, len);
1080}
1081EXPORT_SYMBOL_GPL(xdr_enter_page);
1082
1083static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1084
1085void
1086xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
1087{
1088 buf->head[0] = *iov;
1089 buf->tail[0] = empty_iov;
1090 buf->page_len = 0;
1091 buf->buflen = buf->len = iov->iov_len;
1092}
1093EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1094
1095/**
1096 * xdr_buf_subsegment - set subbuf to a portion of buf
1097 * @buf: an xdr buffer
1098 * @subbuf: the result buffer
1099 * @base: beginning of range in bytes
1100 * @len: length of range in bytes
1101 *
1102 * sets @subbuf to an xdr buffer representing the portion of @buf of
1103 * length @len starting at offset @base.
1104 *
1105 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1106 *
1107 * Returns -1 if base of length are out of bounds.
1108 */
1109int
1110xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
1111 unsigned int base, unsigned int len)
1112{
1113 subbuf->buflen = subbuf->len = len;
1114 if (base < buf->head[0].iov_len) {
1115 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1116 subbuf->head[0].iov_len = min_t(unsigned int, len,
1117 buf->head[0].iov_len - base);
1118 len -= subbuf->head[0].iov_len;
1119 base = 0;
1120 } else {
1121 base -= buf->head[0].iov_len;
1122 subbuf->head[0].iov_len = 0;
1123 }
1124
1125 if (base < buf->page_len) {
1126 subbuf->page_len = min(buf->page_len - base, len);
1127 base += buf->page_base;
1128 subbuf->page_base = base & ~PAGE_MASK;
1129 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1130 len -= subbuf->page_len;
1131 base = 0;
1132 } else {
1133 base -= buf->page_len;
1134 subbuf->page_len = 0;
1135 }
1136
1137 if (base < buf->tail[0].iov_len) {
1138 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1139 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1140 buf->tail[0].iov_len - base);
1141 len -= subbuf->tail[0].iov_len;
1142 base = 0;
1143 } else {
1144 base -= buf->tail[0].iov_len;
1145 subbuf->tail[0].iov_len = 0;
1146 }
1147
1148 if (base || len)
1149 return -1;
1150 return 0;
1151}
1152EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1153
1154static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
1155{
1156 unsigned int this_len;
1157
1158 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1159 memcpy(obj, subbuf->head[0].iov_base, this_len);
1160 len -= this_len;
1161 obj += this_len;
1162 this_len = min_t(unsigned int, len, subbuf->page_len);
1163 if (this_len)
1164 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1165 len -= this_len;
1166 obj += this_len;
1167 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1168 memcpy(obj, subbuf->tail[0].iov_base, this_len);
1169}
1170
1171/* obj is assumed to point to allocated memory of size at least len: */
1172int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
1173{
1174 struct xdr_buf subbuf;
1175 int status;
1176
1177 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1178 if (status != 0)
1179 return status;
1180 __read_bytes_from_xdr_buf(&subbuf, obj, len);
1181 return 0;
1182}
1183EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1184
1185static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
1186{
1187 unsigned int this_len;
1188
1189 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1190 memcpy(subbuf->head[0].iov_base, obj, this_len);
1191 len -= this_len;
1192 obj += this_len;
1193 this_len = min_t(unsigned int, len, subbuf->page_len);
1194 if (this_len)
1195 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1196 len -= this_len;
1197 obj += this_len;
1198 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1199 memcpy(subbuf->tail[0].iov_base, obj, this_len);
1200}
1201
1202/* obj is assumed to point to allocated memory of size at least len: */
1203int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
1204{
1205 struct xdr_buf subbuf;
1206 int status;
1207
1208 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1209 if (status != 0)
1210 return status;
1211 __write_bytes_to_xdr_buf(&subbuf, obj, len);
1212 return 0;
1213}
1214EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1215
1216int
1217xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
1218{
1219 __be32 raw;
1220 int status;
1221
1222 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1223 if (status)
1224 return status;
1225 *obj = be32_to_cpu(raw);
1226 return 0;
1227}
1228EXPORT_SYMBOL_GPL(xdr_decode_word);
1229
1230int
1231xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
1232{
1233 __be32 raw = cpu_to_be32(obj);
1234
1235 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1236}
1237EXPORT_SYMBOL_GPL(xdr_encode_word);
1238
1239/**
1240 * xdr_buf_read_mic() - obtain the address of the GSS mic from xdr buf
1241 * @buf: pointer to buffer containing a mic
1242 * @mic: on success, returns the address of the mic
1243 * @offset: the offset in buf where mic may be found
1244 *
1245 * This function may modify the xdr buf if the mic is found to be straddling
1246 * a boundary between head, pages, and tail. On success the mic can be read
1247 * from the address returned. There is no need to free the mic.
1248 *
1249 * Return: Success returns 0, otherwise an integer error.
1250 */
1251int xdr_buf_read_mic(struct xdr_buf *buf, struct xdr_netobj *mic, unsigned int offset)
1252{
1253 struct xdr_buf subbuf;
1254 unsigned int boundary;
1255
1256 if (xdr_decode_word(buf, offset, &mic->len))
1257 return -EFAULT;
1258 offset += 4;
1259
1260 /* Is the mic partially in the head? */
1261 boundary = buf->head[0].iov_len;
1262 if (offset < boundary && (offset + mic->len) > boundary)
1263 xdr_shift_buf(buf, boundary - offset);
1264
1265 /* Is the mic partially in the pages? */
1266 boundary += buf->page_len;
1267 if (offset < boundary && (offset + mic->len) > boundary)
1268 xdr_shrink_pagelen(buf, boundary - offset);
1269
1270 if (xdr_buf_subsegment(buf, &subbuf, offset, mic->len))
1271 return -EFAULT;
1272
1273 /* Is the mic contained entirely in the head? */
1274 mic->data = subbuf.head[0].iov_base;
1275 if (subbuf.head[0].iov_len == mic->len)
1276 return 0;
1277 /* ..or is the mic contained entirely in the tail? */
1278 mic->data = subbuf.tail[0].iov_base;
1279 if (subbuf.tail[0].iov_len == mic->len)
1280 return 0;
1281
1282 /* Find a contiguous area in @buf to hold all of @mic */
1283 if (mic->len > buf->buflen - buf->len)
1284 return -ENOMEM;
1285 if (buf->tail[0].iov_len != 0)
1286 mic->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
1287 else
1288 mic->data = buf->head[0].iov_base + buf->head[0].iov_len;
1289 __read_bytes_from_xdr_buf(&subbuf, mic->data, mic->len);
1290 return 0;
1291}
1292EXPORT_SYMBOL_GPL(xdr_buf_read_mic);
1293
1294/* Returns 0 on success, or else a negative error code. */
1295static int
1296xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
1297 struct xdr_array2_desc *desc, int encode)
1298{
1299 char *elem = NULL, *c;
1300 unsigned int copied = 0, todo, avail_here;
1301 struct page **ppages = NULL;
1302 int err;
1303
1304 if (encode) {
1305 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1306 return -EINVAL;
1307 } else {
1308 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1309 desc->array_len > desc->array_maxlen ||
1310 (unsigned long) base + 4 + desc->array_len *
1311 desc->elem_size > buf->len)
1312 return -EINVAL;
1313 }
1314 base += 4;
1315
1316 if (!desc->xcode)
1317 return 0;
1318
1319 todo = desc->array_len * desc->elem_size;
1320
1321 /* process head */
1322 if (todo && base < buf->head->iov_len) {
1323 c = buf->head->iov_base + base;
1324 avail_here = min_t(unsigned int, todo,
1325 buf->head->iov_len - base);
1326 todo -= avail_here;
1327
1328 while (avail_here >= desc->elem_size) {
1329 err = desc->xcode(desc, c);
1330 if (err)
1331 goto out;
1332 c += desc->elem_size;
1333 avail_here -= desc->elem_size;
1334 }
1335 if (avail_here) {
1336 if (!elem) {
1337 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1338 err = -ENOMEM;
1339 if (!elem)
1340 goto out;
1341 }
1342 if (encode) {
1343 err = desc->xcode(desc, elem);
1344 if (err)
1345 goto out;
1346 memcpy(c, elem, avail_here);
1347 } else
1348 memcpy(elem, c, avail_here);
1349 copied = avail_here;
1350 }
1351 base = buf->head->iov_len; /* align to start of pages */
1352 }
1353
1354 /* process pages array */
1355 base -= buf->head->iov_len;
1356 if (todo && base < buf->page_len) {
1357 unsigned int avail_page;
1358
1359 avail_here = min(todo, buf->page_len - base);
1360 todo -= avail_here;
1361
1362 base += buf->page_base;
1363 ppages = buf->pages + (base >> PAGE_SHIFT);
1364 base &= ~PAGE_MASK;
1365 avail_page = min_t(unsigned int, PAGE_SIZE - base,
1366 avail_here);
1367 c = kmap(*ppages) + base;
1368
1369 while (avail_here) {
1370 avail_here -= avail_page;
1371 if (copied || avail_page < desc->elem_size) {
1372 unsigned int l = min(avail_page,
1373 desc->elem_size - copied);
1374 if (!elem) {
1375 elem = kmalloc(desc->elem_size,
1376 GFP_KERNEL);
1377 err = -ENOMEM;
1378 if (!elem)
1379 goto out;
1380 }
1381 if (encode) {
1382 if (!copied) {
1383 err = desc->xcode(desc, elem);
1384 if (err)
1385 goto out;
1386 }
1387 memcpy(c, elem + copied, l);
1388 copied += l;
1389 if (copied == desc->elem_size)
1390 copied = 0;
1391 } else {
1392 memcpy(elem + copied, c, l);
1393 copied += l;
1394 if (copied == desc->elem_size) {
1395 err = desc->xcode(desc, elem);
1396 if (err)
1397 goto out;
1398 copied = 0;
1399 }
1400 }
1401 avail_page -= l;
1402 c += l;
1403 }
1404 while (avail_page >= desc->elem_size) {
1405 err = desc->xcode(desc, c);
1406 if (err)
1407 goto out;
1408 c += desc->elem_size;
1409 avail_page -= desc->elem_size;
1410 }
1411 if (avail_page) {
1412 unsigned int l = min(avail_page,
1413 desc->elem_size - copied);
1414 if (!elem) {
1415 elem = kmalloc(desc->elem_size,
1416 GFP_KERNEL);
1417 err = -ENOMEM;
1418 if (!elem)
1419 goto out;
1420 }
1421 if (encode) {
1422 if (!copied) {
1423 err = desc->xcode(desc, elem);
1424 if (err)
1425 goto out;
1426 }
1427 memcpy(c, elem + copied, l);
1428 copied += l;
1429 if (copied == desc->elem_size)
1430 copied = 0;
1431 } else {
1432 memcpy(elem + copied, c, l);
1433 copied += l;
1434 if (copied == desc->elem_size) {
1435 err = desc->xcode(desc, elem);
1436 if (err)
1437 goto out;
1438 copied = 0;
1439 }
1440 }
1441 }
1442 if (avail_here) {
1443 kunmap(*ppages);
1444 ppages++;
1445 c = kmap(*ppages);
1446 }
1447
1448 avail_page = min(avail_here,
1449 (unsigned int) PAGE_SIZE);
1450 }
1451 base = buf->page_len; /* align to start of tail */
1452 }
1453
1454 /* process tail */
1455 base -= buf->page_len;
1456 if (todo) {
1457 c = buf->tail->iov_base + base;
1458 if (copied) {
1459 unsigned int l = desc->elem_size - copied;
1460
1461 if (encode)
1462 memcpy(c, elem + copied, l);
1463 else {
1464 memcpy(elem + copied, c, l);
1465 err = desc->xcode(desc, elem);
1466 if (err)
1467 goto out;
1468 }
1469 todo -= l;
1470 c += l;
1471 }
1472 while (todo) {
1473 err = desc->xcode(desc, c);
1474 if (err)
1475 goto out;
1476 c += desc->elem_size;
1477 todo -= desc->elem_size;
1478 }
1479 }
1480 err = 0;
1481
1482out:
1483 kfree(elem);
1484 if (ppages)
1485 kunmap(*ppages);
1486 return err;
1487}
1488
1489int
1490xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
1491 struct xdr_array2_desc *desc)
1492{
1493 if (base >= buf->len)
1494 return -EINVAL;
1495
1496 return xdr_xcode_array2(buf, base, desc, 0);
1497}
1498EXPORT_SYMBOL_GPL(xdr_decode_array2);
1499
1500int
1501xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
1502 struct xdr_array2_desc *desc)
1503{
1504 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
1505 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
1506 return -EINVAL;
1507
1508 return xdr_xcode_array2(buf, base, desc, 1);
1509}
1510EXPORT_SYMBOL_GPL(xdr_encode_array2);
1511
1512int
1513xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
1514 int (*actor)(struct scatterlist *, void *), void *data)
1515{
1516 int i, ret = 0;
1517 unsigned int page_len, thislen, page_offset;
1518 struct scatterlist sg[1];
1519
1520 sg_init_table(sg, 1);
1521
1522 if (offset >= buf->head[0].iov_len) {
1523 offset -= buf->head[0].iov_len;
1524 } else {
1525 thislen = buf->head[0].iov_len - offset;
1526 if (thislen > len)
1527 thislen = len;
1528 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
1529 ret = actor(sg, data);
1530 if (ret)
1531 goto out;
1532 offset = 0;
1533 len -= thislen;
1534 }
1535 if (len == 0)
1536 goto out;
1537
1538 if (offset >= buf->page_len) {
1539 offset -= buf->page_len;
1540 } else {
1541 page_len = buf->page_len - offset;
1542 if (page_len > len)
1543 page_len = len;
1544 len -= page_len;
1545 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
1546 i = (offset + buf->page_base) >> PAGE_SHIFT;
1547 thislen = PAGE_SIZE - page_offset;
1548 do {
1549 if (thislen > page_len)
1550 thislen = page_len;
1551 sg_set_page(sg, buf->pages[i], thislen, page_offset);
1552 ret = actor(sg, data);
1553 if (ret)
1554 goto out;
1555 page_len -= thislen;
1556 i++;
1557 page_offset = 0;
1558 thislen = PAGE_SIZE;
1559 } while (page_len != 0);
1560 offset = 0;
1561 }
1562 if (len == 0)
1563 goto out;
1564 if (offset < buf->tail[0].iov_len) {
1565 thislen = buf->tail[0].iov_len - offset;
1566 if (thislen > len)
1567 thislen = len;
1568 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
1569 ret = actor(sg, data);
1570 len -= thislen;
1571 }
1572 if (len != 0)
1573 ret = -EINVAL;
1574out:
1575 return ret;
1576}
1577EXPORT_SYMBOL_GPL(xdr_process_buf);
1578
1579/**
1580 * xdr_stream_decode_opaque - Decode variable length opaque
1581 * @xdr: pointer to xdr_stream
1582 * @ptr: location to store opaque data
1583 * @size: size of storage buffer @ptr
1584 *
1585 * Return values:
1586 * On success, returns size of object stored in *@ptr
1587 * %-EBADMSG on XDR buffer overflow
1588 * %-EMSGSIZE on overflow of storage buffer @ptr
1589 */
1590ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
1591{
1592 ssize_t ret;
1593 void *p;
1594
1595 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
1596 if (ret <= 0)
1597 return ret;
1598 memcpy(ptr, p, ret);
1599 return ret;
1600}
1601EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
1602
1603/**
1604 * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
1605 * @xdr: pointer to xdr_stream
1606 * @ptr: location to store pointer to opaque data
1607 * @maxlen: maximum acceptable object size
1608 * @gfp_flags: GFP mask to use
1609 *
1610 * Return values:
1611 * On success, returns size of object stored in *@ptr
1612 * %-EBADMSG on XDR buffer overflow
1613 * %-EMSGSIZE if the size of the object would exceed @maxlen
1614 * %-ENOMEM on memory allocation failure
1615 */
1616ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
1617 size_t maxlen, gfp_t gfp_flags)
1618{
1619 ssize_t ret;
1620 void *p;
1621
1622 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
1623 if (ret > 0) {
1624 *ptr = kmemdup(p, ret, gfp_flags);
1625 if (*ptr != NULL)
1626 return ret;
1627 ret = -ENOMEM;
1628 }
1629 *ptr = NULL;
1630 return ret;
1631}
1632EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
1633
1634/**
1635 * xdr_stream_decode_string - Decode variable length string
1636 * @xdr: pointer to xdr_stream
1637 * @str: location to store string
1638 * @size: size of storage buffer @str
1639 *
1640 * Return values:
1641 * On success, returns length of NUL-terminated string stored in *@str
1642 * %-EBADMSG on XDR buffer overflow
1643 * %-EMSGSIZE on overflow of storage buffer @str
1644 */
1645ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
1646{
1647 ssize_t ret;
1648 void *p;
1649
1650 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
1651 if (ret > 0) {
1652 memcpy(str, p, ret);
1653 str[ret] = '\0';
1654 return strlen(str);
1655 }
1656 *str = '\0';
1657 return ret;
1658}
1659EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
1660
1661/**
1662 * xdr_stream_decode_string_dup - Decode and duplicate variable length string
1663 * @xdr: pointer to xdr_stream
1664 * @str: location to store pointer to string
1665 * @maxlen: maximum acceptable string length
1666 * @gfp_flags: GFP mask to use
1667 *
1668 * Return values:
1669 * On success, returns length of NUL-terminated string stored in *@ptr
1670 * %-EBADMSG on XDR buffer overflow
1671 * %-EMSGSIZE if the size of the string would exceed @maxlen
1672 * %-ENOMEM on memory allocation failure
1673 */
1674ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
1675 size_t maxlen, gfp_t gfp_flags)
1676{
1677 void *p;
1678 ssize_t ret;
1679
1680 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
1681 if (ret > 0) {
1682 char *s = kmalloc(ret + 1, gfp_flags);
1683 if (s != NULL) {
1684 memcpy(s, p, ret);
1685 s[ret] = '\0';
1686 *str = s;
1687 return strlen(s);
1688 }
1689 ret = -ENOMEM;
1690 }
1691 *str = NULL;
1692 return ret;
1693}
1694EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);
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_inline_pages(struct xdr_buf *xdr, unsigned int offset,
133 struct page **pages, unsigned int base, unsigned int len)
134{
135 struct kvec *head = xdr->head;
136 struct kvec *tail = xdr->tail;
137 char *buf = (char *)head->iov_base;
138 unsigned int buflen = head->iov_len;
139
140 head->iov_len = offset;
141
142 xdr->pages = pages;
143 xdr->page_base = base;
144 xdr->page_len = len;
145
146 tail->iov_base = buf + offset;
147 tail->iov_len = buflen - offset;
148
149 xdr->buflen += len;
150}
151EXPORT_SYMBOL_GPL(xdr_inline_pages);
152
153/*
154 * Helper routines for doing 'memmove' like operations on a struct xdr_buf
155 */
156
157/**
158 * _shift_data_right_pages
159 * @pages: vector of pages containing both the source and dest memory area.
160 * @pgto_base: page vector address of destination
161 * @pgfrom_base: page vector address of source
162 * @len: number of bytes to copy
163 *
164 * Note: the addresses pgto_base and pgfrom_base are both calculated in
165 * the same way:
166 * if a memory area starts at byte 'base' in page 'pages[i]',
167 * then its address is given as (i << PAGE_SHIFT) + base
168 * Also note: pgfrom_base must be < pgto_base, but the memory areas
169 * they point to may overlap.
170 */
171static void
172_shift_data_right_pages(struct page **pages, size_t pgto_base,
173 size_t pgfrom_base, size_t len)
174{
175 struct page **pgfrom, **pgto;
176 char *vfrom, *vto;
177 size_t copy;
178
179 BUG_ON(pgto_base <= pgfrom_base);
180
181 pgto_base += len;
182 pgfrom_base += len;
183
184 pgto = pages + (pgto_base >> PAGE_SHIFT);
185 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
186
187 pgto_base &= ~PAGE_MASK;
188 pgfrom_base &= ~PAGE_MASK;
189
190 do {
191 /* Are any pointers crossing a page boundary? */
192 if (pgto_base == 0) {
193 pgto_base = PAGE_SIZE;
194 pgto--;
195 }
196 if (pgfrom_base == 0) {
197 pgfrom_base = PAGE_SIZE;
198 pgfrom--;
199 }
200
201 copy = len;
202 if (copy > pgto_base)
203 copy = pgto_base;
204 if (copy > pgfrom_base)
205 copy = pgfrom_base;
206 pgto_base -= copy;
207 pgfrom_base -= copy;
208
209 vto = kmap_atomic(*pgto);
210 if (*pgto != *pgfrom) {
211 vfrom = kmap_atomic(*pgfrom);
212 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
213 kunmap_atomic(vfrom);
214 } else
215 memmove(vto + pgto_base, vto + pgfrom_base, copy);
216 flush_dcache_page(*pgto);
217 kunmap_atomic(vto);
218
219 } while ((len -= copy) != 0);
220}
221
222/**
223 * _copy_to_pages
224 * @pages: array of pages
225 * @pgbase: page vector address of destination
226 * @p: pointer to source data
227 * @len: length
228 *
229 * Copies data from an arbitrary memory location into an array of pages
230 * The copy is assumed to be non-overlapping.
231 */
232static void
233_copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
234{
235 struct page **pgto;
236 char *vto;
237 size_t copy;
238
239 pgto = pages + (pgbase >> PAGE_SHIFT);
240 pgbase &= ~PAGE_MASK;
241
242 for (;;) {
243 copy = PAGE_SIZE - pgbase;
244 if (copy > len)
245 copy = len;
246
247 vto = kmap_atomic(*pgto);
248 memcpy(vto + pgbase, p, copy);
249 kunmap_atomic(vto);
250
251 len -= copy;
252 if (len == 0)
253 break;
254
255 pgbase += copy;
256 if (pgbase == PAGE_SIZE) {
257 flush_dcache_page(*pgto);
258 pgbase = 0;
259 pgto++;
260 }
261 p += copy;
262 }
263 flush_dcache_page(*pgto);
264}
265
266/**
267 * _copy_from_pages
268 * @p: pointer to destination
269 * @pages: array of pages
270 * @pgbase: offset of source data
271 * @len: length
272 *
273 * Copies data into an arbitrary memory location from an array of pages
274 * The copy is assumed to be non-overlapping.
275 */
276void
277_copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
278{
279 struct page **pgfrom;
280 char *vfrom;
281 size_t copy;
282
283 pgfrom = pages + (pgbase >> PAGE_SHIFT);
284 pgbase &= ~PAGE_MASK;
285
286 do {
287 copy = PAGE_SIZE - pgbase;
288 if (copy > len)
289 copy = len;
290
291 vfrom = kmap_atomic(*pgfrom);
292 memcpy(p, vfrom + pgbase, copy);
293 kunmap_atomic(vfrom);
294
295 pgbase += copy;
296 if (pgbase == PAGE_SIZE) {
297 pgbase = 0;
298 pgfrom++;
299 }
300 p += copy;
301
302 } while ((len -= copy) != 0);
303}
304EXPORT_SYMBOL_GPL(_copy_from_pages);
305
306/**
307 * xdr_shrink_bufhead
308 * @buf: xdr_buf
309 * @len: bytes to remove from buf->head[0]
310 *
311 * Shrinks XDR buffer's header kvec buf->head[0] by
312 * 'len' bytes. The extra data is not lost, but is instead
313 * moved into the inlined pages and/or the tail.
314 */
315static void
316xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
317{
318 struct kvec *head, *tail;
319 size_t copy, offs;
320 unsigned int pglen = buf->page_len;
321
322 tail = buf->tail;
323 head = buf->head;
324
325 WARN_ON_ONCE(len > head->iov_len);
326 if (len > head->iov_len)
327 len = head->iov_len;
328
329 /* Shift the tail first */
330 if (tail->iov_len != 0) {
331 if (tail->iov_len > len) {
332 copy = tail->iov_len - len;
333 memmove((char *)tail->iov_base + len,
334 tail->iov_base, copy);
335 }
336 /* Copy from the inlined pages into the tail */
337 copy = len;
338 if (copy > pglen)
339 copy = pglen;
340 offs = len - copy;
341 if (offs >= tail->iov_len)
342 copy = 0;
343 else if (copy > tail->iov_len - offs)
344 copy = tail->iov_len - offs;
345 if (copy != 0)
346 _copy_from_pages((char *)tail->iov_base + offs,
347 buf->pages,
348 buf->page_base + pglen + offs - len,
349 copy);
350 /* Do we also need to copy data from the head into the tail ? */
351 if (len > pglen) {
352 offs = copy = len - pglen;
353 if (copy > tail->iov_len)
354 copy = tail->iov_len;
355 memcpy(tail->iov_base,
356 (char *)head->iov_base +
357 head->iov_len - offs,
358 copy);
359 }
360 }
361 /* Now handle pages */
362 if (pglen != 0) {
363 if (pglen > len)
364 _shift_data_right_pages(buf->pages,
365 buf->page_base + len,
366 buf->page_base,
367 pglen - len);
368 copy = len;
369 if (len > pglen)
370 copy = pglen;
371 _copy_to_pages(buf->pages, buf->page_base,
372 (char *)head->iov_base + head->iov_len - len,
373 copy);
374 }
375 head->iov_len -= len;
376 buf->buflen -= len;
377 /* Have we truncated the message? */
378 if (buf->len > buf->buflen)
379 buf->len = buf->buflen;
380}
381
382/**
383 * xdr_shrink_pagelen
384 * @buf: xdr_buf
385 * @len: bytes to remove from buf->pages
386 *
387 * Shrinks XDR buffer's page array buf->pages by
388 * 'len' bytes. The extra data is not lost, but is instead
389 * moved into the tail.
390 */
391static void
392xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
393{
394 struct kvec *tail;
395 size_t copy;
396 unsigned int pglen = buf->page_len;
397 unsigned int tailbuf_len;
398
399 tail = buf->tail;
400 BUG_ON (len > pglen);
401
402 tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
403
404 /* Shift the tail first */
405 if (tailbuf_len != 0) {
406 unsigned int free_space = tailbuf_len - tail->iov_len;
407
408 if (len < free_space)
409 free_space = len;
410 tail->iov_len += free_space;
411
412 copy = len;
413 if (tail->iov_len > len) {
414 char *p = (char *)tail->iov_base + len;
415 memmove(p, tail->iov_base, tail->iov_len - len);
416 } else
417 copy = tail->iov_len;
418 /* Copy from the inlined pages into the tail */
419 _copy_from_pages((char *)tail->iov_base,
420 buf->pages, buf->page_base + pglen - len,
421 copy);
422 }
423 buf->page_len -= len;
424 buf->buflen -= len;
425 /* Have we truncated the message? */
426 if (buf->len > buf->buflen)
427 buf->len = buf->buflen;
428}
429
430void
431xdr_shift_buf(struct xdr_buf *buf, size_t len)
432{
433 xdr_shrink_bufhead(buf, len);
434}
435EXPORT_SYMBOL_GPL(xdr_shift_buf);
436
437/**
438 * xdr_stream_pos - Return the current offset from the start of the xdr_stream
439 * @xdr: pointer to struct xdr_stream
440 */
441unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
442{
443 return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
444}
445EXPORT_SYMBOL_GPL(xdr_stream_pos);
446
447/**
448 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
449 * @xdr: pointer to xdr_stream struct
450 * @buf: pointer to XDR buffer in which to encode data
451 * @p: current pointer inside XDR buffer
452 *
453 * Note: at the moment the RPC client only passes the length of our
454 * scratch buffer in the xdr_buf's header kvec. Previously this
455 * meant we needed to call xdr_adjust_iovec() after encoding the
456 * data. With the new scheme, the xdr_stream manages the details
457 * of the buffer length, and takes care of adjusting the kvec
458 * length for us.
459 */
460void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
461{
462 struct kvec *iov = buf->head;
463 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
464
465 xdr_set_scratch_buffer(xdr, NULL, 0);
466 BUG_ON(scratch_len < 0);
467 xdr->buf = buf;
468 xdr->iov = iov;
469 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
470 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
471 BUG_ON(iov->iov_len > scratch_len);
472
473 if (p != xdr->p && p != NULL) {
474 size_t len;
475
476 BUG_ON(p < xdr->p || p > xdr->end);
477 len = (char *)p - (char *)xdr->p;
478 xdr->p = p;
479 buf->len += len;
480 iov->iov_len += len;
481 }
482}
483EXPORT_SYMBOL_GPL(xdr_init_encode);
484
485/**
486 * xdr_commit_encode - Ensure all data is written to buffer
487 * @xdr: pointer to xdr_stream
488 *
489 * We handle encoding across page boundaries by giving the caller a
490 * temporary location to write to, then later copying the data into
491 * place; xdr_commit_encode does that copying.
492 *
493 * Normally the caller doesn't need to call this directly, as the
494 * following xdr_reserve_space will do it. But an explicit call may be
495 * required at the end of encoding, or any other time when the xdr_buf
496 * data might be read.
497 */
498void xdr_commit_encode(struct xdr_stream *xdr)
499{
500 int shift = xdr->scratch.iov_len;
501 void *page;
502
503 if (shift == 0)
504 return;
505 page = page_address(*xdr->page_ptr);
506 memcpy(xdr->scratch.iov_base, page, shift);
507 memmove(page, page + shift, (void *)xdr->p - page);
508 xdr->scratch.iov_len = 0;
509}
510EXPORT_SYMBOL_GPL(xdr_commit_encode);
511
512static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
513 size_t nbytes)
514{
515 static __be32 *p;
516 int space_left;
517 int frag1bytes, frag2bytes;
518
519 if (nbytes > PAGE_SIZE)
520 return NULL; /* Bigger buffers require special handling */
521 if (xdr->buf->len + nbytes > xdr->buf->buflen)
522 return NULL; /* Sorry, we're totally out of space */
523 frag1bytes = (xdr->end - xdr->p) << 2;
524 frag2bytes = nbytes - frag1bytes;
525 if (xdr->iov)
526 xdr->iov->iov_len += frag1bytes;
527 else
528 xdr->buf->page_len += frag1bytes;
529 xdr->page_ptr++;
530 xdr->iov = NULL;
531 /*
532 * If the last encode didn't end exactly on a page boundary, the
533 * next one will straddle boundaries. Encode into the next
534 * page, then copy it back later in xdr_commit_encode. We use
535 * the "scratch" iov to track any temporarily unused fragment of
536 * space at the end of the previous buffer:
537 */
538 xdr->scratch.iov_base = xdr->p;
539 xdr->scratch.iov_len = frag1bytes;
540 p = page_address(*xdr->page_ptr);
541 /*
542 * Note this is where the next encode will start after we've
543 * shifted this one back:
544 */
545 xdr->p = (void *)p + frag2bytes;
546 space_left = xdr->buf->buflen - xdr->buf->len;
547 xdr->end = (void *)p + min_t(int, space_left, PAGE_SIZE);
548 xdr->buf->page_len += frag2bytes;
549 xdr->buf->len += nbytes;
550 return p;
551}
552
553/**
554 * xdr_reserve_space - Reserve buffer space for sending
555 * @xdr: pointer to xdr_stream
556 * @nbytes: number of bytes to reserve
557 *
558 * Checks that we have enough buffer space to encode 'nbytes' more
559 * bytes of data. If so, update the total xdr_buf length, and
560 * adjust the length of the current kvec.
561 */
562__be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
563{
564 __be32 *p = xdr->p;
565 __be32 *q;
566
567 xdr_commit_encode(xdr);
568 /* align nbytes on the next 32-bit boundary */
569 nbytes += 3;
570 nbytes &= ~3;
571 q = p + (nbytes >> 2);
572 if (unlikely(q > xdr->end || q < p))
573 return xdr_get_next_encode_buffer(xdr, nbytes);
574 xdr->p = q;
575 if (xdr->iov)
576 xdr->iov->iov_len += nbytes;
577 else
578 xdr->buf->page_len += nbytes;
579 xdr->buf->len += nbytes;
580 return p;
581}
582EXPORT_SYMBOL_GPL(xdr_reserve_space);
583
584/**
585 * xdr_truncate_encode - truncate an encode buffer
586 * @xdr: pointer to xdr_stream
587 * @len: new length of buffer
588 *
589 * Truncates the xdr stream, so that xdr->buf->len == len,
590 * and xdr->p points at offset len from the start of the buffer, and
591 * head, tail, and page lengths are adjusted to correspond.
592 *
593 * If this means moving xdr->p to a different buffer, we assume that
594 * that the end pointer should be set to the end of the current page,
595 * except in the case of the head buffer when we assume the head
596 * buffer's current length represents the end of the available buffer.
597 *
598 * This is *not* safe to use on a buffer that already has inlined page
599 * cache pages (as in a zero-copy server read reply), except for the
600 * simple case of truncating from one position in the tail to another.
601 *
602 */
603void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
604{
605 struct xdr_buf *buf = xdr->buf;
606 struct kvec *head = buf->head;
607 struct kvec *tail = buf->tail;
608 int fraglen;
609 int new;
610
611 if (len > buf->len) {
612 WARN_ON_ONCE(1);
613 return;
614 }
615 xdr_commit_encode(xdr);
616
617 fraglen = min_t(int, buf->len - len, tail->iov_len);
618 tail->iov_len -= fraglen;
619 buf->len -= fraglen;
620 if (tail->iov_len) {
621 xdr->p = tail->iov_base + tail->iov_len;
622 WARN_ON_ONCE(!xdr->end);
623 WARN_ON_ONCE(!xdr->iov);
624 return;
625 }
626 WARN_ON_ONCE(fraglen);
627 fraglen = min_t(int, buf->len - len, buf->page_len);
628 buf->page_len -= fraglen;
629 buf->len -= fraglen;
630
631 new = buf->page_base + buf->page_len;
632
633 xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
634
635 if (buf->page_len) {
636 xdr->p = page_address(*xdr->page_ptr);
637 xdr->end = (void *)xdr->p + PAGE_SIZE;
638 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
639 WARN_ON_ONCE(xdr->iov);
640 return;
641 }
642 if (fraglen) {
643 xdr->end = head->iov_base + head->iov_len;
644 xdr->page_ptr--;
645 }
646 /* (otherwise assume xdr->end is already set) */
647 head->iov_len = len;
648 buf->len = len;
649 xdr->p = head->iov_base + head->iov_len;
650 xdr->iov = buf->head;
651}
652EXPORT_SYMBOL(xdr_truncate_encode);
653
654/**
655 * xdr_restrict_buflen - decrease available buffer space
656 * @xdr: pointer to xdr_stream
657 * @newbuflen: new maximum number of bytes available
658 *
659 * Adjust our idea of how much space is available in the buffer.
660 * If we've already used too much space in the buffer, returns -1.
661 * If the available space is already smaller than newbuflen, returns 0
662 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
663 * and ensures xdr->end is set at most offset newbuflen from the start
664 * of the buffer.
665 */
666int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
667{
668 struct xdr_buf *buf = xdr->buf;
669 int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
670 int end_offset = buf->len + left_in_this_buf;
671
672 if (newbuflen < 0 || newbuflen < buf->len)
673 return -1;
674 if (newbuflen > buf->buflen)
675 return 0;
676 if (newbuflen < end_offset)
677 xdr->end = (void *)xdr->end + newbuflen - end_offset;
678 buf->buflen = newbuflen;
679 return 0;
680}
681EXPORT_SYMBOL(xdr_restrict_buflen);
682
683/**
684 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
685 * @xdr: pointer to xdr_stream
686 * @pages: list of pages
687 * @base: offset of first byte
688 * @len: length of data in bytes
689 *
690 */
691void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
692 unsigned int len)
693{
694 struct xdr_buf *buf = xdr->buf;
695 struct kvec *iov = buf->tail;
696 buf->pages = pages;
697 buf->page_base = base;
698 buf->page_len = len;
699
700 iov->iov_base = (char *)xdr->p;
701 iov->iov_len = 0;
702 xdr->iov = iov;
703
704 if (len & 3) {
705 unsigned int pad = 4 - (len & 3);
706
707 BUG_ON(xdr->p >= xdr->end);
708 iov->iov_base = (char *)xdr->p + (len & 3);
709 iov->iov_len += pad;
710 len += pad;
711 *xdr->p++ = 0;
712 }
713 buf->buflen += len;
714 buf->len += len;
715}
716EXPORT_SYMBOL_GPL(xdr_write_pages);
717
718static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
719 unsigned int len)
720{
721 if (len > iov->iov_len)
722 len = iov->iov_len;
723 xdr->p = (__be32*)iov->iov_base;
724 xdr->end = (__be32*)(iov->iov_base + len);
725 xdr->iov = iov;
726 xdr->page_ptr = NULL;
727}
728
729static int xdr_set_page_base(struct xdr_stream *xdr,
730 unsigned int base, unsigned int len)
731{
732 unsigned int pgnr;
733 unsigned int maxlen;
734 unsigned int pgoff;
735 unsigned int pgend;
736 void *kaddr;
737
738 maxlen = xdr->buf->page_len;
739 if (base >= maxlen)
740 return -EINVAL;
741 maxlen -= base;
742 if (len > maxlen)
743 len = maxlen;
744
745 base += xdr->buf->page_base;
746
747 pgnr = base >> PAGE_SHIFT;
748 xdr->page_ptr = &xdr->buf->pages[pgnr];
749 kaddr = page_address(*xdr->page_ptr);
750
751 pgoff = base & ~PAGE_MASK;
752 xdr->p = (__be32*)(kaddr + pgoff);
753
754 pgend = pgoff + len;
755 if (pgend > PAGE_SIZE)
756 pgend = PAGE_SIZE;
757 xdr->end = (__be32*)(kaddr + pgend);
758 xdr->iov = NULL;
759 return 0;
760}
761
762static void xdr_set_next_page(struct xdr_stream *xdr)
763{
764 unsigned int newbase;
765
766 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
767 newbase -= xdr->buf->page_base;
768
769 if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
770 xdr_set_iov(xdr, xdr->buf->tail, xdr->nwords << 2);
771}
772
773static bool xdr_set_next_buffer(struct xdr_stream *xdr)
774{
775 if (xdr->page_ptr != NULL)
776 xdr_set_next_page(xdr);
777 else if (xdr->iov == xdr->buf->head) {
778 if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
779 xdr_set_iov(xdr, xdr->buf->tail, xdr->nwords << 2);
780 }
781 return xdr->p != xdr->end;
782}
783
784/**
785 * xdr_init_decode - Initialize an xdr_stream for decoding data.
786 * @xdr: pointer to xdr_stream struct
787 * @buf: pointer to XDR buffer from which to decode data
788 * @p: current pointer inside XDR buffer
789 */
790void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
791{
792 xdr->buf = buf;
793 xdr->scratch.iov_base = NULL;
794 xdr->scratch.iov_len = 0;
795 xdr->nwords = XDR_QUADLEN(buf->len);
796 if (buf->head[0].iov_len != 0)
797 xdr_set_iov(xdr, buf->head, buf->len);
798 else if (buf->page_len != 0)
799 xdr_set_page_base(xdr, 0, buf->len);
800 else
801 xdr_set_iov(xdr, buf->head, buf->len);
802 if (p != NULL && p > xdr->p && xdr->end >= p) {
803 xdr->nwords -= p - xdr->p;
804 xdr->p = p;
805 }
806}
807EXPORT_SYMBOL_GPL(xdr_init_decode);
808
809/**
810 * xdr_init_decode - Initialize an xdr_stream for decoding data.
811 * @xdr: pointer to xdr_stream struct
812 * @buf: pointer to XDR buffer from which to decode data
813 * @pages: list of pages to decode into
814 * @len: length in bytes of buffer in pages
815 */
816void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
817 struct page **pages, unsigned int len)
818{
819 memset(buf, 0, sizeof(*buf));
820 buf->pages = pages;
821 buf->page_len = len;
822 buf->buflen = len;
823 buf->len = len;
824 xdr_init_decode(xdr, buf, NULL);
825}
826EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
827
828static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
829{
830 unsigned int nwords = XDR_QUADLEN(nbytes);
831 __be32 *p = xdr->p;
832 __be32 *q = p + nwords;
833
834 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
835 return NULL;
836 xdr->p = q;
837 xdr->nwords -= nwords;
838 return p;
839}
840
841/**
842 * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
843 * @xdr: pointer to xdr_stream struct
844 * @buf: pointer to an empty buffer
845 * @buflen: size of 'buf'
846 *
847 * The scratch buffer is used when decoding from an array of pages.
848 * If an xdr_inline_decode() call spans across page boundaries, then
849 * we copy the data into the scratch buffer in order to allow linear
850 * access.
851 */
852void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
853{
854 xdr->scratch.iov_base = buf;
855 xdr->scratch.iov_len = buflen;
856}
857EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
858
859static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
860{
861 __be32 *p;
862 char *cpdest = xdr->scratch.iov_base;
863 size_t cplen = (char *)xdr->end - (char *)xdr->p;
864
865 if (nbytes > xdr->scratch.iov_len)
866 return NULL;
867 p = __xdr_inline_decode(xdr, cplen);
868 if (p == NULL)
869 return NULL;
870 memcpy(cpdest, p, cplen);
871 cpdest += cplen;
872 nbytes -= cplen;
873 if (!xdr_set_next_buffer(xdr))
874 return NULL;
875 p = __xdr_inline_decode(xdr, nbytes);
876 if (p == NULL)
877 return NULL;
878 memcpy(cpdest, p, nbytes);
879 return xdr->scratch.iov_base;
880}
881
882/**
883 * xdr_inline_decode - Retrieve XDR data to decode
884 * @xdr: pointer to xdr_stream struct
885 * @nbytes: number of bytes of data to decode
886 *
887 * Check if the input buffer is long enough to enable us to decode
888 * 'nbytes' more bytes of data starting at the current position.
889 * If so return the current pointer, then update the current
890 * pointer position.
891 */
892__be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
893{
894 __be32 *p;
895
896 if (nbytes == 0)
897 return xdr->p;
898 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
899 return NULL;
900 p = __xdr_inline_decode(xdr, nbytes);
901 if (p != NULL)
902 return p;
903 return xdr_copy_to_scratch(xdr, nbytes);
904}
905EXPORT_SYMBOL_GPL(xdr_inline_decode);
906
907static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
908{
909 struct xdr_buf *buf = xdr->buf;
910 struct kvec *iov;
911 unsigned int nwords = XDR_QUADLEN(len);
912 unsigned int cur = xdr_stream_pos(xdr);
913
914 if (xdr->nwords == 0)
915 return 0;
916 /* Realign pages to current pointer position */
917 iov = buf->head;
918 if (iov->iov_len > cur) {
919 xdr_shrink_bufhead(buf, iov->iov_len - cur);
920 xdr->nwords = XDR_QUADLEN(buf->len - cur);
921 }
922
923 if (nwords > xdr->nwords) {
924 nwords = xdr->nwords;
925 len = nwords << 2;
926 }
927 if (buf->page_len <= len)
928 len = buf->page_len;
929 else if (nwords < xdr->nwords) {
930 /* Truncate page data and move it into the tail */
931 xdr_shrink_pagelen(buf, buf->page_len - len);
932 xdr->nwords = XDR_QUADLEN(buf->len - cur);
933 }
934 return len;
935}
936
937/**
938 * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
939 * @xdr: pointer to xdr_stream struct
940 * @len: number of bytes of page data
941 *
942 * Moves data beyond the current pointer position from the XDR head[] buffer
943 * into the page list. Any data that lies beyond current position + "len"
944 * bytes is moved into the XDR tail[].
945 *
946 * Returns the number of XDR encoded bytes now contained in the pages
947 */
948unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
949{
950 struct xdr_buf *buf = xdr->buf;
951 struct kvec *iov;
952 unsigned int nwords;
953 unsigned int end;
954 unsigned int padding;
955
956 len = xdr_align_pages(xdr, len);
957 if (len == 0)
958 return 0;
959 nwords = XDR_QUADLEN(len);
960 padding = (nwords << 2) - len;
961 xdr->iov = iov = buf->tail;
962 /* Compute remaining message length. */
963 end = ((xdr->nwords - nwords) << 2) + padding;
964 if (end > iov->iov_len)
965 end = iov->iov_len;
966
967 /*
968 * Position current pointer at beginning of tail, and
969 * set remaining message length.
970 */
971 xdr->p = (__be32 *)((char *)iov->iov_base + padding);
972 xdr->end = (__be32 *)((char *)iov->iov_base + end);
973 xdr->page_ptr = NULL;
974 xdr->nwords = XDR_QUADLEN(end - padding);
975 return len;
976}
977EXPORT_SYMBOL_GPL(xdr_read_pages);
978
979/**
980 * xdr_enter_page - decode data from the XDR page
981 * @xdr: pointer to xdr_stream struct
982 * @len: number of bytes of page data
983 *
984 * Moves data beyond the current pointer position from the XDR head[] buffer
985 * into the page list. Any data that lies beyond current position + "len"
986 * bytes is moved into the XDR tail[]. The current pointer is then
987 * repositioned at the beginning of the first XDR page.
988 */
989void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
990{
991 len = xdr_align_pages(xdr, len);
992 /*
993 * Position current pointer at beginning of tail, and
994 * set remaining message length.
995 */
996 if (len != 0)
997 xdr_set_page_base(xdr, 0, len);
998}
999EXPORT_SYMBOL_GPL(xdr_enter_page);
1000
1001static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1002
1003void
1004xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
1005{
1006 buf->head[0] = *iov;
1007 buf->tail[0] = empty_iov;
1008 buf->page_len = 0;
1009 buf->buflen = buf->len = iov->iov_len;
1010}
1011EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1012
1013/**
1014 * xdr_buf_subsegment - set subbuf to a portion of buf
1015 * @buf: an xdr buffer
1016 * @subbuf: the result buffer
1017 * @base: beginning of range in bytes
1018 * @len: length of range in bytes
1019 *
1020 * sets @subbuf to an xdr buffer representing the portion of @buf of
1021 * length @len starting at offset @base.
1022 *
1023 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1024 *
1025 * Returns -1 if base of length are out of bounds.
1026 */
1027int
1028xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
1029 unsigned int base, unsigned int len)
1030{
1031 subbuf->buflen = subbuf->len = len;
1032 if (base < buf->head[0].iov_len) {
1033 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1034 subbuf->head[0].iov_len = min_t(unsigned int, len,
1035 buf->head[0].iov_len - base);
1036 len -= subbuf->head[0].iov_len;
1037 base = 0;
1038 } else {
1039 base -= buf->head[0].iov_len;
1040 subbuf->head[0].iov_len = 0;
1041 }
1042
1043 if (base < buf->page_len) {
1044 subbuf->page_len = min(buf->page_len - base, len);
1045 base += buf->page_base;
1046 subbuf->page_base = base & ~PAGE_MASK;
1047 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1048 len -= subbuf->page_len;
1049 base = 0;
1050 } else {
1051 base -= buf->page_len;
1052 subbuf->page_len = 0;
1053 }
1054
1055 if (base < buf->tail[0].iov_len) {
1056 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1057 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1058 buf->tail[0].iov_len - base);
1059 len -= subbuf->tail[0].iov_len;
1060 base = 0;
1061 } else {
1062 base -= buf->tail[0].iov_len;
1063 subbuf->tail[0].iov_len = 0;
1064 }
1065
1066 if (base || len)
1067 return -1;
1068 return 0;
1069}
1070EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1071
1072/**
1073 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1074 * @buf: buf to be trimmed
1075 * @len: number of bytes to reduce "buf" by
1076 *
1077 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1078 * that it's possible that we'll trim less than that amount if the xdr_buf is
1079 * too small, or if (for instance) it's all in the head and the parser has
1080 * already read too far into it.
1081 */
1082void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1083{
1084 size_t cur;
1085 unsigned int trim = len;
1086
1087 if (buf->tail[0].iov_len) {
1088 cur = min_t(size_t, buf->tail[0].iov_len, trim);
1089 buf->tail[0].iov_len -= cur;
1090 trim -= cur;
1091 if (!trim)
1092 goto fix_len;
1093 }
1094
1095 if (buf->page_len) {
1096 cur = min_t(unsigned int, buf->page_len, trim);
1097 buf->page_len -= cur;
1098 trim -= cur;
1099 if (!trim)
1100 goto fix_len;
1101 }
1102
1103 if (buf->head[0].iov_len) {
1104 cur = min_t(size_t, buf->head[0].iov_len, trim);
1105 buf->head[0].iov_len -= cur;
1106 trim -= cur;
1107 }
1108fix_len:
1109 buf->len -= (len - trim);
1110}
1111EXPORT_SYMBOL_GPL(xdr_buf_trim);
1112
1113static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
1114{
1115 unsigned int this_len;
1116
1117 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1118 memcpy(obj, subbuf->head[0].iov_base, this_len);
1119 len -= this_len;
1120 obj += this_len;
1121 this_len = min_t(unsigned int, len, subbuf->page_len);
1122 if (this_len)
1123 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1124 len -= this_len;
1125 obj += this_len;
1126 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1127 memcpy(obj, subbuf->tail[0].iov_base, this_len);
1128}
1129
1130/* obj is assumed to point to allocated memory of size at least len: */
1131int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
1132{
1133 struct xdr_buf subbuf;
1134 int status;
1135
1136 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1137 if (status != 0)
1138 return status;
1139 __read_bytes_from_xdr_buf(&subbuf, obj, len);
1140 return 0;
1141}
1142EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1143
1144static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
1145{
1146 unsigned int this_len;
1147
1148 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1149 memcpy(subbuf->head[0].iov_base, obj, this_len);
1150 len -= this_len;
1151 obj += this_len;
1152 this_len = min_t(unsigned int, len, subbuf->page_len);
1153 if (this_len)
1154 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1155 len -= this_len;
1156 obj += this_len;
1157 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1158 memcpy(subbuf->tail[0].iov_base, obj, this_len);
1159}
1160
1161/* obj is assumed to point to allocated memory of size at least len: */
1162int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
1163{
1164 struct xdr_buf subbuf;
1165 int status;
1166
1167 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1168 if (status != 0)
1169 return status;
1170 __write_bytes_to_xdr_buf(&subbuf, obj, len);
1171 return 0;
1172}
1173EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1174
1175int
1176xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
1177{
1178 __be32 raw;
1179 int status;
1180
1181 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1182 if (status)
1183 return status;
1184 *obj = be32_to_cpu(raw);
1185 return 0;
1186}
1187EXPORT_SYMBOL_GPL(xdr_decode_word);
1188
1189int
1190xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
1191{
1192 __be32 raw = cpu_to_be32(obj);
1193
1194 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1195}
1196EXPORT_SYMBOL_GPL(xdr_encode_word);
1197
1198/* If the netobj starting offset bytes from the start of xdr_buf is contained
1199 * entirely in the head or the tail, set object to point to it; otherwise
1200 * try to find space for it at the end of the tail, copy it there, and
1201 * set obj to point to it. */
1202int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
1203{
1204 struct xdr_buf subbuf;
1205
1206 if (xdr_decode_word(buf, offset, &obj->len))
1207 return -EFAULT;
1208 if (xdr_buf_subsegment(buf, &subbuf, offset + 4, obj->len))
1209 return -EFAULT;
1210
1211 /* Is the obj contained entirely in the head? */
1212 obj->data = subbuf.head[0].iov_base;
1213 if (subbuf.head[0].iov_len == obj->len)
1214 return 0;
1215 /* ..or is the obj contained entirely in the tail? */
1216 obj->data = subbuf.tail[0].iov_base;
1217 if (subbuf.tail[0].iov_len == obj->len)
1218 return 0;
1219
1220 /* use end of tail as storage for obj:
1221 * (We don't copy to the beginning because then we'd have
1222 * to worry about doing a potentially overlapping copy.
1223 * This assumes the object is at most half the length of the
1224 * tail.) */
1225 if (obj->len > buf->buflen - buf->len)
1226 return -ENOMEM;
1227 if (buf->tail[0].iov_len != 0)
1228 obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
1229 else
1230 obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
1231 __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
1232 return 0;
1233}
1234EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
1235
1236/* Returns 0 on success, or else a negative error code. */
1237static int
1238xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
1239 struct xdr_array2_desc *desc, int encode)
1240{
1241 char *elem = NULL, *c;
1242 unsigned int copied = 0, todo, avail_here;
1243 struct page **ppages = NULL;
1244 int err;
1245
1246 if (encode) {
1247 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1248 return -EINVAL;
1249 } else {
1250 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1251 desc->array_len > desc->array_maxlen ||
1252 (unsigned long) base + 4 + desc->array_len *
1253 desc->elem_size > buf->len)
1254 return -EINVAL;
1255 }
1256 base += 4;
1257
1258 if (!desc->xcode)
1259 return 0;
1260
1261 todo = desc->array_len * desc->elem_size;
1262
1263 /* process head */
1264 if (todo && base < buf->head->iov_len) {
1265 c = buf->head->iov_base + base;
1266 avail_here = min_t(unsigned int, todo,
1267 buf->head->iov_len - base);
1268 todo -= avail_here;
1269
1270 while (avail_here >= desc->elem_size) {
1271 err = desc->xcode(desc, c);
1272 if (err)
1273 goto out;
1274 c += desc->elem_size;
1275 avail_here -= desc->elem_size;
1276 }
1277 if (avail_here) {
1278 if (!elem) {
1279 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1280 err = -ENOMEM;
1281 if (!elem)
1282 goto out;
1283 }
1284 if (encode) {
1285 err = desc->xcode(desc, elem);
1286 if (err)
1287 goto out;
1288 memcpy(c, elem, avail_here);
1289 } else
1290 memcpy(elem, c, avail_here);
1291 copied = avail_here;
1292 }
1293 base = buf->head->iov_len; /* align to start of pages */
1294 }
1295
1296 /* process pages array */
1297 base -= buf->head->iov_len;
1298 if (todo && base < buf->page_len) {
1299 unsigned int avail_page;
1300
1301 avail_here = min(todo, buf->page_len - base);
1302 todo -= avail_here;
1303
1304 base += buf->page_base;
1305 ppages = buf->pages + (base >> PAGE_SHIFT);
1306 base &= ~PAGE_MASK;
1307 avail_page = min_t(unsigned int, PAGE_SIZE - base,
1308 avail_here);
1309 c = kmap(*ppages) + base;
1310
1311 while (avail_here) {
1312 avail_here -= avail_page;
1313 if (copied || avail_page < desc->elem_size) {
1314 unsigned int l = min(avail_page,
1315 desc->elem_size - copied);
1316 if (!elem) {
1317 elem = kmalloc(desc->elem_size,
1318 GFP_KERNEL);
1319 err = -ENOMEM;
1320 if (!elem)
1321 goto out;
1322 }
1323 if (encode) {
1324 if (!copied) {
1325 err = desc->xcode(desc, elem);
1326 if (err)
1327 goto out;
1328 }
1329 memcpy(c, elem + copied, l);
1330 copied += l;
1331 if (copied == desc->elem_size)
1332 copied = 0;
1333 } else {
1334 memcpy(elem + copied, c, l);
1335 copied += l;
1336 if (copied == desc->elem_size) {
1337 err = desc->xcode(desc, elem);
1338 if (err)
1339 goto out;
1340 copied = 0;
1341 }
1342 }
1343 avail_page -= l;
1344 c += l;
1345 }
1346 while (avail_page >= desc->elem_size) {
1347 err = desc->xcode(desc, c);
1348 if (err)
1349 goto out;
1350 c += desc->elem_size;
1351 avail_page -= desc->elem_size;
1352 }
1353 if (avail_page) {
1354 unsigned int l = min(avail_page,
1355 desc->elem_size - copied);
1356 if (!elem) {
1357 elem = kmalloc(desc->elem_size,
1358 GFP_KERNEL);
1359 err = -ENOMEM;
1360 if (!elem)
1361 goto out;
1362 }
1363 if (encode) {
1364 if (!copied) {
1365 err = desc->xcode(desc, elem);
1366 if (err)
1367 goto out;
1368 }
1369 memcpy(c, elem + copied, l);
1370 copied += l;
1371 if (copied == desc->elem_size)
1372 copied = 0;
1373 } else {
1374 memcpy(elem + copied, c, l);
1375 copied += l;
1376 if (copied == desc->elem_size) {
1377 err = desc->xcode(desc, elem);
1378 if (err)
1379 goto out;
1380 copied = 0;
1381 }
1382 }
1383 }
1384 if (avail_here) {
1385 kunmap(*ppages);
1386 ppages++;
1387 c = kmap(*ppages);
1388 }
1389
1390 avail_page = min(avail_here,
1391 (unsigned int) PAGE_SIZE);
1392 }
1393 base = buf->page_len; /* align to start of tail */
1394 }
1395
1396 /* process tail */
1397 base -= buf->page_len;
1398 if (todo) {
1399 c = buf->tail->iov_base + base;
1400 if (copied) {
1401 unsigned int l = desc->elem_size - copied;
1402
1403 if (encode)
1404 memcpy(c, elem + copied, l);
1405 else {
1406 memcpy(elem + copied, c, l);
1407 err = desc->xcode(desc, elem);
1408 if (err)
1409 goto out;
1410 }
1411 todo -= l;
1412 c += l;
1413 }
1414 while (todo) {
1415 err = desc->xcode(desc, c);
1416 if (err)
1417 goto out;
1418 c += desc->elem_size;
1419 todo -= desc->elem_size;
1420 }
1421 }
1422 err = 0;
1423
1424out:
1425 kfree(elem);
1426 if (ppages)
1427 kunmap(*ppages);
1428 return err;
1429}
1430
1431int
1432xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
1433 struct xdr_array2_desc *desc)
1434{
1435 if (base >= buf->len)
1436 return -EINVAL;
1437
1438 return xdr_xcode_array2(buf, base, desc, 0);
1439}
1440EXPORT_SYMBOL_GPL(xdr_decode_array2);
1441
1442int
1443xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
1444 struct xdr_array2_desc *desc)
1445{
1446 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
1447 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
1448 return -EINVAL;
1449
1450 return xdr_xcode_array2(buf, base, desc, 1);
1451}
1452EXPORT_SYMBOL_GPL(xdr_encode_array2);
1453
1454int
1455xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
1456 int (*actor)(struct scatterlist *, void *), void *data)
1457{
1458 int i, ret = 0;
1459 unsigned int page_len, thislen, page_offset;
1460 struct scatterlist sg[1];
1461
1462 sg_init_table(sg, 1);
1463
1464 if (offset >= buf->head[0].iov_len) {
1465 offset -= buf->head[0].iov_len;
1466 } else {
1467 thislen = buf->head[0].iov_len - offset;
1468 if (thislen > len)
1469 thislen = len;
1470 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
1471 ret = actor(sg, data);
1472 if (ret)
1473 goto out;
1474 offset = 0;
1475 len -= thislen;
1476 }
1477 if (len == 0)
1478 goto out;
1479
1480 if (offset >= buf->page_len) {
1481 offset -= buf->page_len;
1482 } else {
1483 page_len = buf->page_len - offset;
1484 if (page_len > len)
1485 page_len = len;
1486 len -= page_len;
1487 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
1488 i = (offset + buf->page_base) >> PAGE_SHIFT;
1489 thislen = PAGE_SIZE - page_offset;
1490 do {
1491 if (thislen > page_len)
1492 thislen = page_len;
1493 sg_set_page(sg, buf->pages[i], thislen, page_offset);
1494 ret = actor(sg, data);
1495 if (ret)
1496 goto out;
1497 page_len -= thislen;
1498 i++;
1499 page_offset = 0;
1500 thislen = PAGE_SIZE;
1501 } while (page_len != 0);
1502 offset = 0;
1503 }
1504 if (len == 0)
1505 goto out;
1506 if (offset < buf->tail[0].iov_len) {
1507 thislen = buf->tail[0].iov_len - offset;
1508 if (thislen > len)
1509 thislen = len;
1510 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
1511 ret = actor(sg, data);
1512 len -= thislen;
1513 }
1514 if (len != 0)
1515 ret = -EINVAL;
1516out:
1517 return ret;
1518}
1519EXPORT_SYMBOL_GPL(xdr_process_buf);
1520