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Linux 3.12.70
[linux/fpc-iii.git] / net / sunrpc / xdr.c
blob1504bb11e4f351d1a79835fa990ac8f22751faf3
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 *
23 xdr_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 }
32 EXPORT_SYMBOL_GPL(xdr_encode_netobj);
33
34 __be32 *
35 xdr_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 }
45 EXPORT_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 }
75 EXPORT_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 }
90 EXPORT_SYMBOL_GPL(xdr_encode_opaque);
91
92 __be32 *
93 xdr_encode_string(__be32 *p, const char *string)
94 {
95 return xdr_encode_array(p, string, strlen(string));
96 }
97 EXPORT_SYMBOL_GPL(xdr_encode_string);
98
99 __be32 *
100 xdr_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 }
112 EXPORT_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 */
120 void
121 xdr_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 }
129 EXPORT_SYMBOL_GPL(xdr_terminate_string);
130
131 void
132 xdr_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 }
151 EXPORT_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_CACHE_SHIFT) + base
168 * Also note: pgfrom_base must be < pgto_base, but the memory areas
169 * they point to may overlap.
170 */
171 static 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_CACHE_SHIFT);
185 pgfrom = pages + (pgfrom_base >> PAGE_CACHE_SHIFT);
186
187 pgto_base &= ~PAGE_CACHE_MASK;
188 pgfrom_base &= ~PAGE_CACHE_MASK;
189
190 do {
191 /* Are any pointers crossing a page boundary? */
192 if (pgto_base == 0) {
193 pgto_base = PAGE_CACHE_SIZE;
194 pgto--;
195 }
196 if (pgfrom_base == 0) {
197 pgfrom_base = PAGE_CACHE_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 */
232 static 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_CACHE_SHIFT);
240 pgbase &= ~PAGE_CACHE_MASK;
241
242 for (;;) {
243 copy = PAGE_CACHE_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_CACHE_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 */
276 void
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_CACHE_SHIFT);
284 pgbase &= ~PAGE_CACHE_MASK;
285
286 do {
287 copy = PAGE_CACHE_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_CACHE_SIZE) {
297 pgbase = 0;
298 pgfrom++;
299 }
300 p += copy;
301
302 } while ((len -= copy) != 0);
303 }
304 EXPORT_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 */
315 static void
316 xdr_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 */
391 static void
392 xdr_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
430 void
431 xdr_shift_buf(struct xdr_buf *buf, size_t len)
432 {
433 xdr_shrink_bufhead(buf, len);
434 }
435 EXPORT_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 */
441 unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
442 {
443 return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
444 }
445 EXPORT_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 */
460 void 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 BUG_ON(scratch_len < 0);
466 xdr->buf = buf;
467 xdr->iov = iov;
468 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
469 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
470 BUG_ON(iov->iov_len > scratch_len);
471
472 if (p != xdr->p && p != NULL) {
473 size_t len;
474
475 BUG_ON(p < xdr->p || p > xdr->end);
476 len = (char *)p - (char *)xdr->p;
477 xdr->p = p;
478 buf->len += len;
479 iov->iov_len += len;
480 }
481 }
482 EXPORT_SYMBOL_GPL(xdr_init_encode);
483
484 /**
485 * xdr_reserve_space - Reserve buffer space for sending
486 * @xdr: pointer to xdr_stream
487 * @nbytes: number of bytes to reserve
488 *
489 * Checks that we have enough buffer space to encode 'nbytes' more
490 * bytes of data. If so, update the total xdr_buf length, and
491 * adjust the length of the current kvec.
492 */
493 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
494 {
495 __be32 *p = xdr->p;
496 __be32 *q;
497
498 /* align nbytes on the next 32-bit boundary */
499 nbytes += 3;
500 nbytes &= ~3;
501 q = p + (nbytes >> 2);
502 if (unlikely(q > xdr->end || q < p))
503 return NULL;
504 xdr->p = q;
505 xdr->iov->iov_len += nbytes;
506 xdr->buf->len += nbytes;
507 return p;
508 }
509 EXPORT_SYMBOL_GPL(xdr_reserve_space);
510
511 /**
512 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
513 * @xdr: pointer to xdr_stream
514 * @pages: list of pages
515 * @base: offset of first byte
516 * @len: length of data in bytes
517 *
518 */
519 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
520 unsigned int len)
521 {
522 struct xdr_buf *buf = xdr->buf;
523 struct kvec *iov = buf->tail;
524 buf->pages = pages;
525 buf->page_base = base;
526 buf->page_len = len;
527
528 iov->iov_base = (char *)xdr->p;
529 iov->iov_len = 0;
530 xdr->iov = iov;
531
532 if (len & 3) {
533 unsigned int pad = 4 - (len & 3);
534
535 BUG_ON(xdr->p >= xdr->end);
536 iov->iov_base = (char *)xdr->p + (len & 3);
537 iov->iov_len += pad;
538 len += pad;
539 *xdr->p++ = 0;
540 }
541 buf->buflen += len;
542 buf->len += len;
543 }
544 EXPORT_SYMBOL_GPL(xdr_write_pages);
545
546 static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
547 unsigned int len)
548 {
549 if (len > iov->iov_len)
550 len = iov->iov_len;
551 xdr->p = (__be32*)iov->iov_base;
552 xdr->end = (__be32*)(iov->iov_base + len);
553 xdr->iov = iov;
554 xdr->page_ptr = NULL;
555 }
556
557 static int xdr_set_page_base(struct xdr_stream *xdr,
558 unsigned int base, unsigned int len)
559 {
560 unsigned int pgnr;
561 unsigned int maxlen;
562 unsigned int pgoff;
563 unsigned int pgend;
564 void *kaddr;
565
566 maxlen = xdr->buf->page_len;
567 if (base >= maxlen)
568 return -EINVAL;
569 maxlen -= base;
570 if (len > maxlen)
571 len = maxlen;
572
573 base += xdr->buf->page_base;
574
575 pgnr = base >> PAGE_SHIFT;
576 xdr->page_ptr = &xdr->buf->pages[pgnr];
577 kaddr = page_address(*xdr->page_ptr);
578
579 pgoff = base & ~PAGE_MASK;
580 xdr->p = (__be32*)(kaddr + pgoff);
581
582 pgend = pgoff + len;
583 if (pgend > PAGE_SIZE)
584 pgend = PAGE_SIZE;
585 xdr->end = (__be32*)(kaddr + pgend);
586 xdr->iov = NULL;
587 return 0;
588 }
589
590 static void xdr_set_next_page(struct xdr_stream *xdr)
591 {
592 unsigned int newbase;
593
594 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
595 newbase -= xdr->buf->page_base;
596
597 if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
598 xdr_set_iov(xdr, xdr->buf->tail, xdr->buf->len);
599 }
600
601 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
602 {
603 if (xdr->page_ptr != NULL)
604 xdr_set_next_page(xdr);
605 else if (xdr->iov == xdr->buf->head) {
606 if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
607 xdr_set_iov(xdr, xdr->buf->tail, xdr->buf->len);
608 }
609 return xdr->p != xdr->end;
610 }
611
612 /**
613 * xdr_init_decode - Initialize an xdr_stream for decoding data.
614 * @xdr: pointer to xdr_stream struct
615 * @buf: pointer to XDR buffer from which to decode data
616 * @p: current pointer inside XDR buffer
617 */
618 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
619 {
620 xdr->buf = buf;
621 xdr->scratch.iov_base = NULL;
622 xdr->scratch.iov_len = 0;
623 xdr->nwords = XDR_QUADLEN(buf->len);
624 if (buf->head[0].iov_len != 0)
625 xdr_set_iov(xdr, buf->head, buf->len);
626 else if (buf->page_len != 0)
627 xdr_set_page_base(xdr, 0, buf->len);
628 if (p != NULL && p > xdr->p && xdr->end >= p) {
629 xdr->nwords -= p - xdr->p;
630 xdr->p = p;
631 }
632 }
633 EXPORT_SYMBOL_GPL(xdr_init_decode);
634
635 /**
636 * xdr_init_decode - Initialize an xdr_stream for decoding data.
637 * @xdr: pointer to xdr_stream struct
638 * @buf: pointer to XDR buffer from which to decode data
639 * @pages: list of pages to decode into
640 * @len: length in bytes of buffer in pages
641 */
642 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
643 struct page **pages, unsigned int len)
644 {
645 memset(buf, 0, sizeof(*buf));
646 buf->pages = pages;
647 buf->page_len = len;
648 buf->buflen = len;
649 buf->len = len;
650 xdr_init_decode(xdr, buf, NULL);
651 }
652 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
653
654 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
655 {
656 unsigned int nwords = XDR_QUADLEN(nbytes);
657 __be32 *p = xdr->p;
658 __be32 *q = p + nwords;
659
660 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
661 return NULL;
662 xdr->p = q;
663 xdr->nwords -= nwords;
664 return p;
665 }
666
667 /**
668 * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
669 * @xdr: pointer to xdr_stream struct
670 * @buf: pointer to an empty buffer
671 * @buflen: size of 'buf'
672 *
673 * The scratch buffer is used when decoding from an array of pages.
674 * If an xdr_inline_decode() call spans across page boundaries, then
675 * we copy the data into the scratch buffer in order to allow linear
676 * access.
677 */
678 void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
679 {
680 xdr->scratch.iov_base = buf;
681 xdr->scratch.iov_len = buflen;
682 }
683 EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
684
685 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
686 {
687 __be32 *p;
688 void *cpdest = xdr->scratch.iov_base;
689 size_t cplen = (char *)xdr->end - (char *)xdr->p;
690
691 if (nbytes > xdr->scratch.iov_len)
692 return NULL;
693 memcpy(cpdest, xdr->p, cplen);
694 cpdest += cplen;
695 nbytes -= cplen;
696 if (!xdr_set_next_buffer(xdr))
697 return NULL;
698 p = __xdr_inline_decode(xdr, nbytes);
699 if (p == NULL)
700 return NULL;
701 memcpy(cpdest, p, nbytes);
702 return xdr->scratch.iov_base;
703 }
704
705 /**
706 * xdr_inline_decode - Retrieve XDR data to decode
707 * @xdr: pointer to xdr_stream struct
708 * @nbytes: number of bytes of data to decode
709 *
710 * Check if the input buffer is long enough to enable us to decode
711 * 'nbytes' more bytes of data starting at the current position.
712 * If so return the current pointer, then update the current
713 * pointer position.
714 */
715 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
716 {
717 __be32 *p;
718
719 if (nbytes == 0)
720 return xdr->p;
721 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
722 return NULL;
723 p = __xdr_inline_decode(xdr, nbytes);
724 if (p != NULL)
725 return p;
726 return xdr_copy_to_scratch(xdr, nbytes);
727 }
728 EXPORT_SYMBOL_GPL(xdr_inline_decode);
729
730 static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
731 {
732 struct xdr_buf *buf = xdr->buf;
733 struct kvec *iov;
734 unsigned int nwords = XDR_QUADLEN(len);
735 unsigned int cur = xdr_stream_pos(xdr);
736
737 if (xdr->nwords == 0)
738 return 0;
739 /* Realign pages to current pointer position */
740 iov = buf->head;
741 if (iov->iov_len > cur) {
742 xdr_shrink_bufhead(buf, iov->iov_len - cur);
743 xdr->nwords = XDR_QUADLEN(buf->len - cur);
744 }
745
746 if (nwords > xdr->nwords) {
747 nwords = xdr->nwords;
748 len = nwords << 2;
749 }
750 if (buf->page_len <= len)
751 len = buf->page_len;
752 else if (nwords < xdr->nwords) {
753 /* Truncate page data and move it into the tail */
754 xdr_shrink_pagelen(buf, buf->page_len - len);
755 xdr->nwords = XDR_QUADLEN(buf->len - cur);
756 }
757 return len;
758 }
759
760 /**
761 * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
762 * @xdr: pointer to xdr_stream struct
763 * @len: number of bytes of page data
764 *
765 * Moves data beyond the current pointer position from the XDR head[] buffer
766 * into the page list. Any data that lies beyond current position + "len"
767 * bytes is moved into the XDR tail[].
768 *
769 * Returns the number of XDR encoded bytes now contained in the pages
770 */
771 unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
772 {
773 struct xdr_buf *buf = xdr->buf;
774 struct kvec *iov;
775 unsigned int nwords;
776 unsigned int end;
777 unsigned int padding;
778
779 len = xdr_align_pages(xdr, len);
780 if (len == 0)
781 return 0;
782 nwords = XDR_QUADLEN(len);
783 padding = (nwords << 2) - len;
784 xdr->iov = iov = buf->tail;
785 /* Compute remaining message length. */
786 end = ((xdr->nwords - nwords) << 2) + padding;
787 if (end > iov->iov_len)
788 end = iov->iov_len;
789
790 /*
791 * Position current pointer at beginning of tail, and
792 * set remaining message length.
793 */
794 xdr->p = (__be32 *)((char *)iov->iov_base + padding);
795 xdr->end = (__be32 *)((char *)iov->iov_base + end);
796 xdr->page_ptr = NULL;
797 xdr->nwords = XDR_QUADLEN(end - padding);
798 return len;
799 }
800 EXPORT_SYMBOL_GPL(xdr_read_pages);
801
802 /**
803 * xdr_enter_page - decode data from the XDR page
804 * @xdr: pointer to xdr_stream struct
805 * @len: number of bytes of page data
806 *
807 * Moves data beyond the current pointer position from the XDR head[] buffer
808 * into the page list. Any data that lies beyond current position + "len"
809 * bytes is moved into the XDR tail[]. The current pointer is then
810 * repositioned at the beginning of the first XDR page.
811 */
812 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
813 {
814 len = xdr_align_pages(xdr, len);
815 /*
816 * Position current pointer at beginning of tail, and
817 * set remaining message length.
818 */
819 if (len != 0)
820 xdr_set_page_base(xdr, 0, len);
821 }
822 EXPORT_SYMBOL_GPL(xdr_enter_page);
823
824 static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
825
826 void
827 xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
828 {
829 buf->head[0] = *iov;
830 buf->tail[0] = empty_iov;
831 buf->page_len = 0;
832 buf->buflen = buf->len = iov->iov_len;
833 }
834 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
835
836 /* Sets subbuf to the portion of buf of length len beginning base bytes
837 * from the start of buf. Returns -1 if base of length are out of bounds. */
838 int
839 xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
840 unsigned int base, unsigned int len)
841 {
842 subbuf->buflen = subbuf->len = len;
843 if (base < buf->head[0].iov_len) {
844 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
845 subbuf->head[0].iov_len = min_t(unsigned int, len,
846 buf->head[0].iov_len - base);
847 len -= subbuf->head[0].iov_len;
848 base = 0;
849 } else {
850 subbuf->head[0].iov_base = NULL;
851 subbuf->head[0].iov_len = 0;
852 base -= buf->head[0].iov_len;
853 }
854
855 if (base < buf->page_len) {
856 subbuf->page_len = min(buf->page_len - base, len);
857 base += buf->page_base;
858 subbuf->page_base = base & ~PAGE_CACHE_MASK;
859 subbuf->pages = &buf->pages[base >> PAGE_CACHE_SHIFT];
860 len -= subbuf->page_len;
861 base = 0;
862 } else {
863 base -= buf->page_len;
864 subbuf->page_len = 0;
865 }
866
867 if (base < buf->tail[0].iov_len) {
868 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
869 subbuf->tail[0].iov_len = min_t(unsigned int, len,
870 buf->tail[0].iov_len - base);
871 len -= subbuf->tail[0].iov_len;
872 base = 0;
873 } else {
874 subbuf->tail[0].iov_base = NULL;
875 subbuf->tail[0].iov_len = 0;
876 base -= buf->tail[0].iov_len;
877 }
878
879 if (base || len)
880 return -1;
881 return 0;
882 }
883 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
884
885 /**
886 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
887 * @buf: buf to be trimmed
888 * @len: number of bytes to reduce "buf" by
889 *
890 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
891 * that it's possible that we'll trim less than that amount if the xdr_buf is
892 * too small, or if (for instance) it's all in the head and the parser has
893 * already read too far into it.
894 */
895 void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
896 {
897 size_t cur;
898 unsigned int trim = len;
899
900 if (buf->tail[0].iov_len) {
901 cur = min_t(size_t, buf->tail[0].iov_len, trim);
902 buf->tail[0].iov_len -= cur;
903 trim -= cur;
904 if (!trim)
905 goto fix_len;
906 }
907
908 if (buf->page_len) {
909 cur = min_t(unsigned int, buf->page_len, trim);
910 buf->page_len -= cur;
911 trim -= cur;
912 if (!trim)
913 goto fix_len;
914 }
915
916 if (buf->head[0].iov_len) {
917 cur = min_t(size_t, buf->head[0].iov_len, trim);
918 buf->head[0].iov_len -= cur;
919 trim -= cur;
920 }
921 fix_len:
922 buf->len -= (len - trim);
923 }
924 EXPORT_SYMBOL_GPL(xdr_buf_trim);
925
926 static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
927 {
928 unsigned int this_len;
929
930 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
931 memcpy(obj, subbuf->head[0].iov_base, this_len);
932 len -= this_len;
933 obj += this_len;
934 this_len = min_t(unsigned int, len, subbuf->page_len);
935 if (this_len)
936 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
937 len -= this_len;
938 obj += this_len;
939 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
940 memcpy(obj, subbuf->tail[0].iov_base, this_len);
941 }
942
943 /* obj is assumed to point to allocated memory of size at least len: */
944 int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
945 {
946 struct xdr_buf subbuf;
947 int status;
948
949 status = xdr_buf_subsegment(buf, &subbuf, base, len);
950 if (status != 0)
951 return status;
952 __read_bytes_from_xdr_buf(&subbuf, obj, len);
953 return 0;
954 }
955 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
956
957 static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
958 {
959 unsigned int this_len;
960
961 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
962 memcpy(subbuf->head[0].iov_base, obj, this_len);
963 len -= this_len;
964 obj += this_len;
965 this_len = min_t(unsigned int, len, subbuf->page_len);
966 if (this_len)
967 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
968 len -= this_len;
969 obj += this_len;
970 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
971 memcpy(subbuf->tail[0].iov_base, obj, this_len);
972 }
973
974 /* obj is assumed to point to allocated memory of size at least len: */
975 int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
976 {
977 struct xdr_buf subbuf;
978 int status;
979
980 status = xdr_buf_subsegment(buf, &subbuf, base, len);
981 if (status != 0)
982 return status;
983 __write_bytes_to_xdr_buf(&subbuf, obj, len);
984 return 0;
985 }
986 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
987
988 int
989 xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
990 {
991 __be32 raw;
992 int status;
993
994 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
995 if (status)
996 return status;
997 *obj = be32_to_cpu(raw);
998 return 0;
999 }
1000 EXPORT_SYMBOL_GPL(xdr_decode_word);
1001
1002 int
1003 xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
1004 {
1005 __be32 raw = cpu_to_be32(obj);
1006
1007 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1008 }
1009 EXPORT_SYMBOL_GPL(xdr_encode_word);
1010
1011 /* If the netobj starting offset bytes from the start of xdr_buf is contained
1012 * entirely in the head or the tail, set object to point to it; otherwise
1013 * try to find space for it at the end of the tail, copy it there, and
1014 * set obj to point to it. */
1015 int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
1016 {
1017 struct xdr_buf subbuf;
1018
1019 if (xdr_decode_word(buf, offset, &obj->len))
1020 return -EFAULT;
1021 if (xdr_buf_subsegment(buf, &subbuf, offset + 4, obj->len))
1022 return -EFAULT;
1023
1024 /* Is the obj contained entirely in the head? */
1025 obj->data = subbuf.head[0].iov_base;
1026 if (subbuf.head[0].iov_len == obj->len)
1027 return 0;
1028 /* ..or is the obj contained entirely in the tail? */
1029 obj->data = subbuf.tail[0].iov_base;
1030 if (subbuf.tail[0].iov_len == obj->len)
1031 return 0;
1032
1033 /* use end of tail as storage for obj:
1034 * (We don't copy to the beginning because then we'd have
1035 * to worry about doing a potentially overlapping copy.
1036 * This assumes the object is at most half the length of the
1037 * tail.) */
1038 if (obj->len > buf->buflen - buf->len)
1039 return -ENOMEM;
1040 if (buf->tail[0].iov_len != 0)
1041 obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
1042 else
1043 obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
1044 __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
1045 return 0;
1046 }
1047 EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
1048
1049 /* Returns 0 on success, or else a negative error code. */
1050 static int
1051 xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
1052 struct xdr_array2_desc *desc, int encode)
1053 {
1054 char *elem = NULL, *c;
1055 unsigned int copied = 0, todo, avail_here;
1056 struct page **ppages = NULL;
1057 int err;
1058
1059 if (encode) {
1060 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1061 return -EINVAL;
1062 } else {
1063 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1064 desc->array_len > desc->array_maxlen ||
1065 (unsigned long) base + 4 + desc->array_len *
1066 desc->elem_size > buf->len)
1067 return -EINVAL;
1068 }
1069 base += 4;
1070
1071 if (!desc->xcode)
1072 return 0;
1073
1074 todo = desc->array_len * desc->elem_size;
1075
1076 /* process head */
1077 if (todo && base < buf->head->iov_len) {
1078 c = buf->head->iov_base + base;
1079 avail_here = min_t(unsigned int, todo,
1080 buf->head->iov_len - base);
1081 todo -= avail_here;
1082
1083 while (avail_here >= desc->elem_size) {
1084 err = desc->xcode(desc, c);
1085 if (err)
1086 goto out;
1087 c += desc->elem_size;
1088 avail_here -= desc->elem_size;
1089 }
1090 if (avail_here) {
1091 if (!elem) {
1092 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1093 err = -ENOMEM;
1094 if (!elem)
1095 goto out;
1096 }
1097 if (encode) {
1098 err = desc->xcode(desc, elem);
1099 if (err)
1100 goto out;
1101 memcpy(c, elem, avail_here);
1102 } else
1103 memcpy(elem, c, avail_here);
1104 copied = avail_here;
1105 }
1106 base = buf->head->iov_len; /* align to start of pages */
1107 }
1108
1109 /* process pages array */
1110 base -= buf->head->iov_len;
1111 if (todo && base < buf->page_len) {
1112 unsigned int avail_page;
1113
1114 avail_here = min(todo, buf->page_len - base);
1115 todo -= avail_here;
1116
1117 base += buf->page_base;
1118 ppages = buf->pages + (base >> PAGE_CACHE_SHIFT);
1119 base &= ~PAGE_CACHE_MASK;
1120 avail_page = min_t(unsigned int, PAGE_CACHE_SIZE - base,
1121 avail_here);
1122 c = kmap(*ppages) + base;
1123
1124 while (avail_here) {
1125 avail_here -= avail_page;
1126 if (copied || avail_page < desc->elem_size) {
1127 unsigned int l = min(avail_page,
1128 desc->elem_size - copied);
1129 if (!elem) {
1130 elem = kmalloc(desc->elem_size,
1131 GFP_KERNEL);
1132 err = -ENOMEM;
1133 if (!elem)
1134 goto out;
1135 }
1136 if (encode) {
1137 if (!copied) {
1138 err = desc->xcode(desc, elem);
1139 if (err)
1140 goto out;
1141 }
1142 memcpy(c, elem + copied, l);
1143 copied += l;
1144 if (copied == desc->elem_size)
1145 copied = 0;
1146 } else {
1147 memcpy(elem + copied, c, l);
1148 copied += l;
1149 if (copied == desc->elem_size) {
1150 err = desc->xcode(desc, elem);
1151 if (err)
1152 goto out;
1153 copied = 0;
1154 }
1155 }
1156 avail_page -= l;
1157 c += l;
1158 }
1159 while (avail_page >= desc->elem_size) {
1160 err = desc->xcode(desc, c);
1161 if (err)
1162 goto out;
1163 c += desc->elem_size;
1164 avail_page -= desc->elem_size;
1165 }
1166 if (avail_page) {
1167 unsigned int l = min(avail_page,
1168 desc->elem_size - copied);
1169 if (!elem) {
1170 elem = kmalloc(desc->elem_size,
1171 GFP_KERNEL);
1172 err = -ENOMEM;
1173 if (!elem)
1174 goto out;
1175 }
1176 if (encode) {
1177 if (!copied) {
1178 err = desc->xcode(desc, elem);
1179 if (err)
1180 goto out;
1181 }
1182 memcpy(c, elem + copied, l);
1183 copied += l;
1184 if (copied == desc->elem_size)
1185 copied = 0;
1186 } else {
1187 memcpy(elem + copied, c, l);
1188 copied += l;
1189 if (copied == desc->elem_size) {
1190 err = desc->xcode(desc, elem);
1191 if (err)
1192 goto out;
1193 copied = 0;
1194 }
1195 }
1196 }
1197 if (avail_here) {
1198 kunmap(*ppages);
1199 ppages++;
1200 c = kmap(*ppages);
1201 }
1202
1203 avail_page = min(avail_here,
1204 (unsigned int) PAGE_CACHE_SIZE);
1205 }
1206 base = buf->page_len; /* align to start of tail */
1207 }
1208
1209 /* process tail */
1210 base -= buf->page_len;
1211 if (todo) {
1212 c = buf->tail->iov_base + base;
1213 if (copied) {
1214 unsigned int l = desc->elem_size - copied;
1215
1216 if (encode)
1217 memcpy(c, elem + copied, l);
1218 else {
1219 memcpy(elem + copied, c, l);
1220 err = desc->xcode(desc, elem);
1221 if (err)
1222 goto out;
1223 }
1224 todo -= l;
1225 c += l;
1226 }
1227 while (todo) {
1228 err = desc->xcode(desc, c);
1229 if (err)
1230 goto out;
1231 c += desc->elem_size;
1232 todo -= desc->elem_size;
1233 }
1234 }
1235 err = 0;
1236
1237 out:
1238 kfree(elem);
1239 if (ppages)
1240 kunmap(*ppages);
1241 return err;
1242 }
1243
1244 int
1245 xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
1246 struct xdr_array2_desc *desc)
1247 {
1248 if (base >= buf->len)
1249 return -EINVAL;
1250
1251 return xdr_xcode_array2(buf, base, desc, 0);
1252 }
1253 EXPORT_SYMBOL_GPL(xdr_decode_array2);
1254
1255 int
1256 xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
1257 struct xdr_array2_desc *desc)
1258 {
1259 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
1260 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
1261 return -EINVAL;
1262
1263 return xdr_xcode_array2(buf, base, desc, 1);
1264 }
1265 EXPORT_SYMBOL_GPL(xdr_encode_array2);
1266
1267 int
1268 xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
1269 int (*actor)(struct scatterlist *, void *), void *data)
1270 {
1271 int i, ret = 0;
1272 unsigned int page_len, thislen, page_offset;
1273 struct scatterlist sg[1];
1274
1275 sg_init_table(sg, 1);
1276
1277 if (offset >= buf->head[0].iov_len) {
1278 offset -= buf->head[0].iov_len;
1279 } else {
1280 thislen = buf->head[0].iov_len - offset;
1281 if (thislen > len)
1282 thislen = len;
1283 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
1284 ret = actor(sg, data);
1285 if (ret)
1286 goto out;
1287 offset = 0;
1288 len -= thislen;
1289 }
1290 if (len == 0)
1291 goto out;
1292
1293 if (offset >= buf->page_len) {
1294 offset -= buf->page_len;
1295 } else {
1296 page_len = buf->page_len - offset;
1297 if (page_len > len)
1298 page_len = len;
1299 len -= page_len;
1300 page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
1301 i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
1302 thislen = PAGE_CACHE_SIZE - page_offset;
1303 do {
1304 if (thislen > page_len)
1305 thislen = page_len;
1306 sg_set_page(sg, buf->pages[i], thislen, page_offset);
1307 ret = actor(sg, data);
1308 if (ret)
1309 goto out;
1310 page_len -= thislen;
1311 i++;
1312 page_offset = 0;
1313 thislen = PAGE_CACHE_SIZE;
1314 } while (page_len != 0);
1315 offset = 0;
1316 }
1317 if (len == 0)
1318 goto out;
1319 if (offset < buf->tail[0].iov_len) {
1320 thislen = buf->tail[0].iov_len - offset;
1321 if (thislen > len)
1322 thislen = len;
1323 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
1324 ret = actor(sg, data);
1325 len -= thislen;
1326 }
1327 if (len != 0)
1328 ret = -EINVAL;
1329 out:
1330 return ret;
1331 }
1332 EXPORT_SYMBOL_GPL(xdr_process_buf);
1333
Linux with added FPC-III support