Commit | Line | Data |
---|---|---|
1da177e4 LT |
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/types.h> | |
10 | #include <linux/socket.h> | |
11 | #include <linux/string.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/pagemap.h> | |
14 | #include <linux/errno.h> | |
15 | #include <linux/in.h> | |
16 | #include <linux/net.h> | |
17 | #include <net/sock.h> | |
18 | #include <linux/sunrpc/xdr.h> | |
19 | #include <linux/sunrpc/msg_prot.h> | |
20 | ||
21 | /* | |
22 | * XDR functions for basic NFS types | |
23 | */ | |
24 | u32 * | |
25 | xdr_encode_netobj(u32 *p, const struct xdr_netobj *obj) | |
26 | { | |
27 | unsigned int quadlen = XDR_QUADLEN(obj->len); | |
28 | ||
29 | p[quadlen] = 0; /* zero trailing bytes */ | |
30 | *p++ = htonl(obj->len); | |
31 | memcpy(p, obj->data, obj->len); | |
32 | return p + XDR_QUADLEN(obj->len); | |
33 | } | |
34 | ||
35 | u32 * | |
36 | xdr_decode_netobj(u32 *p, struct xdr_netobj *obj) | |
37 | { | |
38 | unsigned int len; | |
39 | ||
40 | if ((len = ntohl(*p++)) > XDR_MAX_NETOBJ) | |
41 | return NULL; | |
42 | obj->len = len; | |
43 | obj->data = (u8 *) p; | |
44 | return p + XDR_QUADLEN(len); | |
45 | } | |
46 | ||
47 | /** | |
48 | * xdr_encode_opaque_fixed - Encode fixed length opaque data | |
4dc3b16b PP |
49 | * @p: pointer to current position in XDR buffer. |
50 | * @ptr: pointer to data to encode (or NULL) | |
51 | * @nbytes: size of data. | |
1da177e4 LT |
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 | u32 *xdr_encode_opaque_fixed(u32 *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(xdr_encode_opaque_fixed); | |
76 | ||
77 | /** | |
78 | * xdr_encode_opaque - Encode variable length opaque data | |
4dc3b16b PP |
79 | * @p: pointer to current position in XDR buffer. |
80 | * @ptr: pointer to data to encode (or NULL) | |
81 | * @nbytes: size of data. | |
1da177e4 LT |
82 | * |
83 | * Returns the updated current XDR buffer position | |
84 | */ | |
85 | u32 *xdr_encode_opaque(u32 *p, const void *ptr, unsigned int nbytes) | |
86 | { | |
87 | *p++ = htonl(nbytes); | |
88 | return xdr_encode_opaque_fixed(p, ptr, nbytes); | |
89 | } | |
90 | EXPORT_SYMBOL(xdr_encode_opaque); | |
91 | ||
92 | u32 * | |
93 | xdr_encode_string(u32 *p, const char *string) | |
94 | { | |
95 | return xdr_encode_array(p, string, strlen(string)); | |
96 | } | |
97 | ||
98 | u32 * | |
99 | xdr_decode_string(u32 *p, char **sp, int *lenp, int maxlen) | |
100 | { | |
101 | unsigned int len; | |
102 | char *string; | |
103 | ||
104 | if ((len = ntohl(*p++)) > maxlen) | |
105 | return NULL; | |
106 | if (lenp) | |
107 | *lenp = len; | |
108 | if ((len % 4) != 0) { | |
109 | string = (char *) p; | |
110 | } else { | |
111 | string = (char *) (p - 1); | |
112 | memmove(string, p, len); | |
113 | } | |
114 | string[len] = '\0'; | |
115 | *sp = string; | |
116 | return p + XDR_QUADLEN(len); | |
117 | } | |
118 | ||
119 | u32 * | |
120 | xdr_decode_string_inplace(u32 *p, char **sp, int *lenp, int maxlen) | |
121 | { | |
122 | unsigned int len; | |
123 | ||
124 | if ((len = ntohl(*p++)) > maxlen) | |
125 | return NULL; | |
126 | *lenp = len; | |
127 | *sp = (char *) p; | |
128 | return p + XDR_QUADLEN(len); | |
129 | } | |
130 | ||
131 | void | |
132 | xdr_encode_pages(struct xdr_buf *xdr, struct page **pages, unsigned int base, | |
133 | unsigned int len) | |
134 | { | |
135 | struct kvec *tail = xdr->tail; | |
136 | u32 *p; | |
137 | ||
138 | xdr->pages = pages; | |
139 | xdr->page_base = base; | |
140 | xdr->page_len = len; | |
141 | ||
142 | p = (u32 *)xdr->head[0].iov_base + XDR_QUADLEN(xdr->head[0].iov_len); | |
143 | tail->iov_base = p; | |
144 | tail->iov_len = 0; | |
145 | ||
146 | if (len & 3) { | |
147 | unsigned int pad = 4 - (len & 3); | |
148 | ||
149 | *p = 0; | |
150 | tail->iov_base = (char *)p + (len & 3); | |
151 | tail->iov_len = pad; | |
152 | len += pad; | |
153 | } | |
154 | xdr->buflen += len; | |
155 | xdr->len += len; | |
156 | } | |
157 | ||
158 | void | |
159 | xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset, | |
160 | struct page **pages, unsigned int base, unsigned int len) | |
161 | { | |
162 | struct kvec *head = xdr->head; | |
163 | struct kvec *tail = xdr->tail; | |
164 | char *buf = (char *)head->iov_base; | |
165 | unsigned int buflen = head->iov_len; | |
166 | ||
167 | head->iov_len = offset; | |
168 | ||
169 | xdr->pages = pages; | |
170 | xdr->page_base = base; | |
171 | xdr->page_len = len; | |
172 | ||
173 | tail->iov_base = buf + offset; | |
174 | tail->iov_len = buflen - offset; | |
175 | ||
176 | xdr->buflen += len; | |
177 | } | |
178 | ||
1da177e4 LT |
179 | |
180 | int | |
181 | xdr_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, | |
182 | struct xdr_buf *xdr, unsigned int base, int msgflags) | |
183 | { | |
184 | struct page **ppage = xdr->pages; | |
185 | unsigned int len, pglen = xdr->page_len; | |
186 | int err, ret = 0; | |
187 | ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int); | |
188 | ||
189 | len = xdr->head[0].iov_len; | |
190 | if (base < len || (addr != NULL && base == 0)) { | |
191 | struct kvec iov = { | |
192 | .iov_base = xdr->head[0].iov_base + base, | |
193 | .iov_len = len - base, | |
194 | }; | |
195 | struct msghdr msg = { | |
196 | .msg_name = addr, | |
197 | .msg_namelen = addrlen, | |
198 | .msg_flags = msgflags, | |
199 | }; | |
200 | if (xdr->len > len) | |
201 | msg.msg_flags |= MSG_MORE; | |
202 | ||
203 | if (iov.iov_len != 0) | |
204 | err = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len); | |
205 | else | |
206 | err = kernel_sendmsg(sock, &msg, NULL, 0, 0); | |
207 | if (ret == 0) | |
208 | ret = err; | |
209 | else if (err > 0) | |
210 | ret += err; | |
211 | if (err != iov.iov_len) | |
212 | goto out; | |
213 | base = 0; | |
214 | } else | |
215 | base -= len; | |
216 | ||
217 | if (pglen == 0) | |
218 | goto copy_tail; | |
219 | if (base >= pglen) { | |
220 | base -= pglen; | |
221 | goto copy_tail; | |
222 | } | |
223 | if (base || xdr->page_base) { | |
224 | pglen -= base; | |
225 | base += xdr->page_base; | |
226 | ppage += base >> PAGE_CACHE_SHIFT; | |
227 | base &= ~PAGE_CACHE_MASK; | |
228 | } | |
229 | ||
230 | sendpage = sock->ops->sendpage ? : sock_no_sendpage; | |
231 | do { | |
232 | int flags = msgflags; | |
233 | ||
234 | len = PAGE_CACHE_SIZE; | |
235 | if (base) | |
236 | len -= base; | |
237 | if (pglen < len) | |
238 | len = pglen; | |
239 | ||
240 | if (pglen != len || xdr->tail[0].iov_len != 0) | |
241 | flags |= MSG_MORE; | |
242 | ||
243 | /* Hmm... We might be dealing with highmem pages */ | |
244 | if (PageHighMem(*ppage)) | |
245 | sendpage = sock_no_sendpage; | |
246 | err = sendpage(sock, *ppage, base, len, flags); | |
247 | if (ret == 0) | |
248 | ret = err; | |
249 | else if (err > 0) | |
250 | ret += err; | |
251 | if (err != len) | |
252 | goto out; | |
253 | base = 0; | |
254 | ppage++; | |
255 | } while ((pglen -= len) != 0); | |
256 | copy_tail: | |
257 | len = xdr->tail[0].iov_len; | |
258 | if (base < len) { | |
259 | struct kvec iov = { | |
260 | .iov_base = xdr->tail[0].iov_base + base, | |
261 | .iov_len = len - base, | |
262 | }; | |
263 | struct msghdr msg = { | |
264 | .msg_flags = msgflags, | |
265 | }; | |
266 | err = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len); | |
267 | if (ret == 0) | |
268 | ret = err; | |
269 | else if (err > 0) | |
270 | ret += err; | |
271 | } | |
272 | out: | |
273 | return ret; | |
274 | } | |
275 | ||
276 | ||
277 | /* | |
278 | * Helper routines for doing 'memmove' like operations on a struct xdr_buf | |
279 | * | |
280 | * _shift_data_right_pages | |
281 | * @pages: vector of pages containing both the source and dest memory area. | |
282 | * @pgto_base: page vector address of destination | |
283 | * @pgfrom_base: page vector address of source | |
284 | * @len: number of bytes to copy | |
285 | * | |
286 | * Note: the addresses pgto_base and pgfrom_base are both calculated in | |
287 | * the same way: | |
288 | * if a memory area starts at byte 'base' in page 'pages[i]', | |
289 | * then its address is given as (i << PAGE_CACHE_SHIFT) + base | |
290 | * Also note: pgfrom_base must be < pgto_base, but the memory areas | |
291 | * they point to may overlap. | |
292 | */ | |
293 | static void | |
294 | _shift_data_right_pages(struct page **pages, size_t pgto_base, | |
295 | size_t pgfrom_base, size_t len) | |
296 | { | |
297 | struct page **pgfrom, **pgto; | |
298 | char *vfrom, *vto; | |
299 | size_t copy; | |
300 | ||
301 | BUG_ON(pgto_base <= pgfrom_base); | |
302 | ||
303 | pgto_base += len; | |
304 | pgfrom_base += len; | |
305 | ||
306 | pgto = pages + (pgto_base >> PAGE_CACHE_SHIFT); | |
307 | pgfrom = pages + (pgfrom_base >> PAGE_CACHE_SHIFT); | |
308 | ||
309 | pgto_base &= ~PAGE_CACHE_MASK; | |
310 | pgfrom_base &= ~PAGE_CACHE_MASK; | |
311 | ||
312 | do { | |
313 | /* Are any pointers crossing a page boundary? */ | |
314 | if (pgto_base == 0) { | |
315 | flush_dcache_page(*pgto); | |
316 | pgto_base = PAGE_CACHE_SIZE; | |
317 | pgto--; | |
318 | } | |
319 | if (pgfrom_base == 0) { | |
320 | pgfrom_base = PAGE_CACHE_SIZE; | |
321 | pgfrom--; | |
322 | } | |
323 | ||
324 | copy = len; | |
325 | if (copy > pgto_base) | |
326 | copy = pgto_base; | |
327 | if (copy > pgfrom_base) | |
328 | copy = pgfrom_base; | |
329 | pgto_base -= copy; | |
330 | pgfrom_base -= copy; | |
331 | ||
332 | vto = kmap_atomic(*pgto, KM_USER0); | |
333 | vfrom = kmap_atomic(*pgfrom, KM_USER1); | |
334 | memmove(vto + pgto_base, vfrom + pgfrom_base, copy); | |
335 | kunmap_atomic(vfrom, KM_USER1); | |
336 | kunmap_atomic(vto, KM_USER0); | |
337 | ||
338 | } while ((len -= copy) != 0); | |
339 | flush_dcache_page(*pgto); | |
340 | } | |
341 | ||
342 | /* | |
343 | * _copy_to_pages | |
344 | * @pages: array of pages | |
345 | * @pgbase: page vector address of destination | |
346 | * @p: pointer to source data | |
347 | * @len: length | |
348 | * | |
349 | * Copies data from an arbitrary memory location into an array of pages | |
350 | * The copy is assumed to be non-overlapping. | |
351 | */ | |
352 | static void | |
353 | _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len) | |
354 | { | |
355 | struct page **pgto; | |
356 | char *vto; | |
357 | size_t copy; | |
358 | ||
359 | pgto = pages + (pgbase >> PAGE_CACHE_SHIFT); | |
360 | pgbase &= ~PAGE_CACHE_MASK; | |
361 | ||
362 | do { | |
363 | copy = PAGE_CACHE_SIZE - pgbase; | |
364 | if (copy > len) | |
365 | copy = len; | |
366 | ||
367 | vto = kmap_atomic(*pgto, KM_USER0); | |
368 | memcpy(vto + pgbase, p, copy); | |
369 | kunmap_atomic(vto, KM_USER0); | |
370 | ||
371 | pgbase += copy; | |
372 | if (pgbase == PAGE_CACHE_SIZE) { | |
373 | flush_dcache_page(*pgto); | |
374 | pgbase = 0; | |
375 | pgto++; | |
376 | } | |
377 | p += copy; | |
378 | ||
379 | } while ((len -= copy) != 0); | |
380 | flush_dcache_page(*pgto); | |
381 | } | |
382 | ||
383 | /* | |
384 | * _copy_from_pages | |
385 | * @p: pointer to destination | |
386 | * @pages: array of pages | |
387 | * @pgbase: offset of source data | |
388 | * @len: length | |
389 | * | |
390 | * Copies data into an arbitrary memory location from an array of pages | |
391 | * The copy is assumed to be non-overlapping. | |
392 | */ | |
393 | static void | |
394 | _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len) | |
395 | { | |
396 | struct page **pgfrom; | |
397 | char *vfrom; | |
398 | size_t copy; | |
399 | ||
400 | pgfrom = pages + (pgbase >> PAGE_CACHE_SHIFT); | |
401 | pgbase &= ~PAGE_CACHE_MASK; | |
402 | ||
403 | do { | |
404 | copy = PAGE_CACHE_SIZE - pgbase; | |
405 | if (copy > len) | |
406 | copy = len; | |
407 | ||
408 | vfrom = kmap_atomic(*pgfrom, KM_USER0); | |
409 | memcpy(p, vfrom + pgbase, copy); | |
410 | kunmap_atomic(vfrom, KM_USER0); | |
411 | ||
412 | pgbase += copy; | |
413 | if (pgbase == PAGE_CACHE_SIZE) { | |
414 | pgbase = 0; | |
415 | pgfrom++; | |
416 | } | |
417 | p += copy; | |
418 | ||
419 | } while ((len -= copy) != 0); | |
420 | } | |
421 | ||
422 | /* | |
423 | * xdr_shrink_bufhead | |
424 | * @buf: xdr_buf | |
425 | * @len: bytes to remove from buf->head[0] | |
426 | * | |
427 | * Shrinks XDR buffer's header kvec buf->head[0] by | |
428 | * 'len' bytes. The extra data is not lost, but is instead | |
429 | * moved into the inlined pages and/or the tail. | |
430 | */ | |
431 | static void | |
432 | xdr_shrink_bufhead(struct xdr_buf *buf, size_t len) | |
433 | { | |
434 | struct kvec *head, *tail; | |
435 | size_t copy, offs; | |
436 | unsigned int pglen = buf->page_len; | |
437 | ||
438 | tail = buf->tail; | |
439 | head = buf->head; | |
440 | BUG_ON (len > head->iov_len); | |
441 | ||
442 | /* Shift the tail first */ | |
443 | if (tail->iov_len != 0) { | |
444 | if (tail->iov_len > len) { | |
445 | copy = tail->iov_len - len; | |
446 | memmove((char *)tail->iov_base + len, | |
447 | tail->iov_base, copy); | |
448 | } | |
449 | /* Copy from the inlined pages into the tail */ | |
450 | copy = len; | |
451 | if (copy > pglen) | |
452 | copy = pglen; | |
453 | offs = len - copy; | |
454 | if (offs >= tail->iov_len) | |
455 | copy = 0; | |
456 | else if (copy > tail->iov_len - offs) | |
457 | copy = tail->iov_len - offs; | |
458 | if (copy != 0) | |
459 | _copy_from_pages((char *)tail->iov_base + offs, | |
460 | buf->pages, | |
461 | buf->page_base + pglen + offs - len, | |
462 | copy); | |
463 | /* Do we also need to copy data from the head into the tail ? */ | |
464 | if (len > pglen) { | |
465 | offs = copy = len - pglen; | |
466 | if (copy > tail->iov_len) | |
467 | copy = tail->iov_len; | |
468 | memcpy(tail->iov_base, | |
469 | (char *)head->iov_base + | |
470 | head->iov_len - offs, | |
471 | copy); | |
472 | } | |
473 | } | |
474 | /* Now handle pages */ | |
475 | if (pglen != 0) { | |
476 | if (pglen > len) | |
477 | _shift_data_right_pages(buf->pages, | |
478 | buf->page_base + len, | |
479 | buf->page_base, | |
480 | pglen - len); | |
481 | copy = len; | |
482 | if (len > pglen) | |
483 | copy = pglen; | |
484 | _copy_to_pages(buf->pages, buf->page_base, | |
485 | (char *)head->iov_base + head->iov_len - len, | |
486 | copy); | |
487 | } | |
488 | head->iov_len -= len; | |
489 | buf->buflen -= len; | |
490 | /* Have we truncated the message? */ | |
491 | if (buf->len > buf->buflen) | |
492 | buf->len = buf->buflen; | |
493 | } | |
494 | ||
495 | /* | |
496 | * xdr_shrink_pagelen | |
497 | * @buf: xdr_buf | |
498 | * @len: bytes to remove from buf->pages | |
499 | * | |
500 | * Shrinks XDR buffer's page array buf->pages by | |
501 | * 'len' bytes. The extra data is not lost, but is instead | |
502 | * moved into the tail. | |
503 | */ | |
504 | static void | |
505 | xdr_shrink_pagelen(struct xdr_buf *buf, size_t len) | |
506 | { | |
507 | struct kvec *tail; | |
508 | size_t copy; | |
509 | char *p; | |
510 | unsigned int pglen = buf->page_len; | |
511 | ||
512 | tail = buf->tail; | |
513 | BUG_ON (len > pglen); | |
514 | ||
515 | /* Shift the tail first */ | |
516 | if (tail->iov_len != 0) { | |
517 | p = (char *)tail->iov_base + len; | |
518 | if (tail->iov_len > len) { | |
519 | copy = tail->iov_len - len; | |
520 | memmove(p, tail->iov_base, copy); | |
521 | } else | |
522 | buf->buflen -= len; | |
523 | /* Copy from the inlined pages into the tail */ | |
524 | copy = len; | |
525 | if (copy > tail->iov_len) | |
526 | copy = tail->iov_len; | |
527 | _copy_from_pages((char *)tail->iov_base, | |
528 | buf->pages, buf->page_base + pglen - len, | |
529 | copy); | |
530 | } | |
531 | buf->page_len -= len; | |
532 | buf->buflen -= len; | |
533 | /* Have we truncated the message? */ | |
534 | if (buf->len > buf->buflen) | |
535 | buf->len = buf->buflen; | |
536 | } | |
537 | ||
538 | void | |
539 | xdr_shift_buf(struct xdr_buf *buf, size_t len) | |
540 | { | |
541 | xdr_shrink_bufhead(buf, len); | |
542 | } | |
543 | ||
544 | /** | |
545 | * xdr_init_encode - Initialize a struct xdr_stream for sending data. | |
546 | * @xdr: pointer to xdr_stream struct | |
547 | * @buf: pointer to XDR buffer in which to encode data | |
548 | * @p: current pointer inside XDR buffer | |
549 | * | |
550 | * Note: at the moment the RPC client only passes the length of our | |
551 | * scratch buffer in the xdr_buf's header kvec. Previously this | |
552 | * meant we needed to call xdr_adjust_iovec() after encoding the | |
553 | * data. With the new scheme, the xdr_stream manages the details | |
554 | * of the buffer length, and takes care of adjusting the kvec | |
555 | * length for us. | |
556 | */ | |
557 | void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, uint32_t *p) | |
558 | { | |
559 | struct kvec *iov = buf->head; | |
334ccfd5 | 560 | int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len; |
1da177e4 | 561 | |
334ccfd5 | 562 | BUG_ON(scratch_len < 0); |
1da177e4 LT |
563 | xdr->buf = buf; |
564 | xdr->iov = iov; | |
334ccfd5 TM |
565 | xdr->p = (uint32_t *)((char *)iov->iov_base + iov->iov_len); |
566 | xdr->end = (uint32_t *)((char *)iov->iov_base + scratch_len); | |
567 | BUG_ON(iov->iov_len > scratch_len); | |
568 | ||
569 | if (p != xdr->p && p != NULL) { | |
570 | size_t len; | |
571 | ||
572 | BUG_ON(p < xdr->p || p > xdr->end); | |
573 | len = (char *)p - (char *)xdr->p; | |
574 | xdr->p = p; | |
575 | buf->len += len; | |
576 | iov->iov_len += len; | |
577 | } | |
1da177e4 LT |
578 | } |
579 | EXPORT_SYMBOL(xdr_init_encode); | |
580 | ||
581 | /** | |
582 | * xdr_reserve_space - Reserve buffer space for sending | |
583 | * @xdr: pointer to xdr_stream | |
584 | * @nbytes: number of bytes to reserve | |
585 | * | |
586 | * Checks that we have enough buffer space to encode 'nbytes' more | |
587 | * bytes of data. If so, update the total xdr_buf length, and | |
588 | * adjust the length of the current kvec. | |
589 | */ | |
590 | uint32_t * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes) | |
591 | { | |
592 | uint32_t *p = xdr->p; | |
593 | uint32_t *q; | |
594 | ||
595 | /* align nbytes on the next 32-bit boundary */ | |
596 | nbytes += 3; | |
597 | nbytes &= ~3; | |
598 | q = p + (nbytes >> 2); | |
599 | if (unlikely(q > xdr->end || q < p)) | |
600 | return NULL; | |
601 | xdr->p = q; | |
602 | xdr->iov->iov_len += nbytes; | |
603 | xdr->buf->len += nbytes; | |
604 | return p; | |
605 | } | |
606 | EXPORT_SYMBOL(xdr_reserve_space); | |
607 | ||
608 | /** | |
609 | * xdr_write_pages - Insert a list of pages into an XDR buffer for sending | |
610 | * @xdr: pointer to xdr_stream | |
611 | * @pages: list of pages | |
612 | * @base: offset of first byte | |
613 | * @len: length of data in bytes | |
614 | * | |
615 | */ | |
616 | void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base, | |
617 | unsigned int len) | |
618 | { | |
619 | struct xdr_buf *buf = xdr->buf; | |
620 | struct kvec *iov = buf->tail; | |
621 | buf->pages = pages; | |
622 | buf->page_base = base; | |
623 | buf->page_len = len; | |
624 | ||
625 | iov->iov_base = (char *)xdr->p; | |
626 | iov->iov_len = 0; | |
627 | xdr->iov = iov; | |
628 | ||
629 | if (len & 3) { | |
630 | unsigned int pad = 4 - (len & 3); | |
631 | ||
632 | BUG_ON(xdr->p >= xdr->end); | |
633 | iov->iov_base = (char *)xdr->p + (len & 3); | |
634 | iov->iov_len += pad; | |
635 | len += pad; | |
636 | *xdr->p++ = 0; | |
637 | } | |
638 | buf->buflen += len; | |
639 | buf->len += len; | |
640 | } | |
641 | EXPORT_SYMBOL(xdr_write_pages); | |
642 | ||
643 | /** | |
644 | * xdr_init_decode - Initialize an xdr_stream for decoding data. | |
645 | * @xdr: pointer to xdr_stream struct | |
646 | * @buf: pointer to XDR buffer from which to decode data | |
647 | * @p: current pointer inside XDR buffer | |
648 | */ | |
649 | void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, uint32_t *p) | |
650 | { | |
651 | struct kvec *iov = buf->head; | |
652 | unsigned int len = iov->iov_len; | |
653 | ||
654 | if (len > buf->len) | |
655 | len = buf->len; | |
656 | xdr->buf = buf; | |
657 | xdr->iov = iov; | |
658 | xdr->p = p; | |
659 | xdr->end = (uint32_t *)((char *)iov->iov_base + len); | |
660 | } | |
661 | EXPORT_SYMBOL(xdr_init_decode); | |
662 | ||
663 | /** | |
664 | * xdr_inline_decode - Retrieve non-page XDR data to decode | |
665 | * @xdr: pointer to xdr_stream struct | |
666 | * @nbytes: number of bytes of data to decode | |
667 | * | |
668 | * Check if the input buffer is long enough to enable us to decode | |
669 | * 'nbytes' more bytes of data starting at the current position. | |
670 | * If so return the current pointer, then update the current | |
671 | * pointer position. | |
672 | */ | |
673 | uint32_t * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes) | |
674 | { | |
675 | uint32_t *p = xdr->p; | |
676 | uint32_t *q = p + XDR_QUADLEN(nbytes); | |
677 | ||
678 | if (unlikely(q > xdr->end || q < p)) | |
679 | return NULL; | |
680 | xdr->p = q; | |
681 | return p; | |
682 | } | |
683 | EXPORT_SYMBOL(xdr_inline_decode); | |
684 | ||
685 | /** | |
686 | * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position | |
687 | * @xdr: pointer to xdr_stream struct | |
688 | * @len: number of bytes of page data | |
689 | * | |
690 | * Moves data beyond the current pointer position from the XDR head[] buffer | |
691 | * into the page list. Any data that lies beyond current position + "len" | |
692 | * bytes is moved into the XDR tail[]. The current pointer is then | |
693 | * repositioned at the beginning of the XDR tail. | |
694 | */ | |
695 | void xdr_read_pages(struct xdr_stream *xdr, unsigned int len) | |
696 | { | |
697 | struct xdr_buf *buf = xdr->buf; | |
698 | struct kvec *iov; | |
699 | ssize_t shift; | |
700 | unsigned int end; | |
701 | int padding; | |
702 | ||
703 | /* Realign pages to current pointer position */ | |
704 | iov = buf->head; | |
705 | shift = iov->iov_len + (char *)iov->iov_base - (char *)xdr->p; | |
706 | if (shift > 0) | |
707 | xdr_shrink_bufhead(buf, shift); | |
708 | ||
709 | /* Truncate page data and move it into the tail */ | |
710 | if (buf->page_len > len) | |
711 | xdr_shrink_pagelen(buf, buf->page_len - len); | |
712 | padding = (XDR_QUADLEN(len) << 2) - len; | |
713 | xdr->iov = iov = buf->tail; | |
714 | /* Compute remaining message length. */ | |
715 | end = iov->iov_len; | |
716 | shift = buf->buflen - buf->len; | |
717 | if (shift < end) | |
718 | end -= shift; | |
719 | else if (shift > 0) | |
720 | end = 0; | |
721 | /* | |
722 | * Position current pointer at beginning of tail, and | |
723 | * set remaining message length. | |
724 | */ | |
725 | xdr->p = (uint32_t *)((char *)iov->iov_base + padding); | |
726 | xdr->end = (uint32_t *)((char *)iov->iov_base + end); | |
727 | } | |
728 | EXPORT_SYMBOL(xdr_read_pages); | |
729 | ||
730 | static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0}; | |
731 | ||
732 | void | |
733 | xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf) | |
734 | { | |
735 | buf->head[0] = *iov; | |
736 | buf->tail[0] = empty_iov; | |
737 | buf->page_len = 0; | |
738 | buf->buflen = buf->len = iov->iov_len; | |
739 | } | |
740 | ||
741 | /* Sets subiov to the intersection of iov with the buffer of length len | |
742 | * starting base bytes after iov. Indicates empty intersection by setting | |
743 | * length of subiov to zero. Decrements len by length of subiov, sets base | |
744 | * to zero (or decrements it by length of iov if subiov is empty). */ | |
745 | static void | |
746 | iov_subsegment(struct kvec *iov, struct kvec *subiov, int *base, int *len) | |
747 | { | |
748 | if (*base > iov->iov_len) { | |
749 | subiov->iov_base = NULL; | |
750 | subiov->iov_len = 0; | |
751 | *base -= iov->iov_len; | |
752 | } else { | |
753 | subiov->iov_base = iov->iov_base + *base; | |
754 | subiov->iov_len = min(*len, (int)iov->iov_len - *base); | |
755 | *base = 0; | |
756 | } | |
757 | *len -= subiov->iov_len; | |
758 | } | |
759 | ||
760 | /* Sets subbuf to the portion of buf of length len beginning base bytes | |
761 | * from the start of buf. Returns -1 if base of length are out of bounds. */ | |
762 | int | |
763 | xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf, | |
764 | int base, int len) | |
765 | { | |
766 | int i; | |
767 | ||
768 | subbuf->buflen = subbuf->len = len; | |
769 | iov_subsegment(buf->head, subbuf->head, &base, &len); | |
770 | ||
771 | if (base < buf->page_len) { | |
772 | i = (base + buf->page_base) >> PAGE_CACHE_SHIFT; | |
773 | subbuf->pages = &buf->pages[i]; | |
774 | subbuf->page_base = (base + buf->page_base) & ~PAGE_CACHE_MASK; | |
775 | subbuf->page_len = min((int)buf->page_len - base, len); | |
776 | len -= subbuf->page_len; | |
777 | base = 0; | |
778 | } else { | |
779 | base -= buf->page_len; | |
780 | subbuf->page_len = 0; | |
781 | } | |
782 | ||
783 | iov_subsegment(buf->tail, subbuf->tail, &base, &len); | |
784 | if (base || len) | |
785 | return -1; | |
786 | return 0; | |
787 | } | |
788 | ||
789 | /* obj is assumed to point to allocated memory of size at least len: */ | |
790 | int | |
791 | read_bytes_from_xdr_buf(struct xdr_buf *buf, int base, void *obj, int len) | |
792 | { | |
793 | struct xdr_buf subbuf; | |
794 | int this_len; | |
795 | int status; | |
796 | ||
797 | status = xdr_buf_subsegment(buf, &subbuf, base, len); | |
798 | if (status) | |
799 | goto out; | |
800 | this_len = min(len, (int)subbuf.head[0].iov_len); | |
801 | memcpy(obj, subbuf.head[0].iov_base, this_len); | |
802 | len -= this_len; | |
803 | obj += this_len; | |
804 | this_len = min(len, (int)subbuf.page_len); | |
805 | if (this_len) | |
806 | _copy_from_pages(obj, subbuf.pages, subbuf.page_base, this_len); | |
807 | len -= this_len; | |
808 | obj += this_len; | |
809 | this_len = min(len, (int)subbuf.tail[0].iov_len); | |
810 | memcpy(obj, subbuf.tail[0].iov_base, this_len); | |
811 | out: | |
812 | return status; | |
813 | } | |
814 | ||
bd8100e7 AG |
815 | /* obj is assumed to point to allocated memory of size at least len: */ |
816 | int | |
817 | write_bytes_to_xdr_buf(struct xdr_buf *buf, int base, void *obj, int len) | |
818 | { | |
819 | struct xdr_buf subbuf; | |
820 | int this_len; | |
821 | int status; | |
822 | ||
823 | status = xdr_buf_subsegment(buf, &subbuf, base, len); | |
824 | if (status) | |
825 | goto out; | |
826 | this_len = min(len, (int)subbuf.head[0].iov_len); | |
827 | memcpy(subbuf.head[0].iov_base, obj, this_len); | |
828 | len -= this_len; | |
829 | obj += this_len; | |
830 | this_len = min(len, (int)subbuf.page_len); | |
831 | if (this_len) | |
832 | _copy_to_pages(subbuf.pages, subbuf.page_base, obj, this_len); | |
833 | len -= this_len; | |
834 | obj += this_len; | |
835 | this_len = min(len, (int)subbuf.tail[0].iov_len); | |
836 | memcpy(subbuf.tail[0].iov_base, obj, this_len); | |
837 | out: | |
838 | return status; | |
839 | } | |
840 | ||
841 | int | |
842 | xdr_decode_word(struct xdr_buf *buf, int base, u32 *obj) | |
1da177e4 LT |
843 | { |
844 | u32 raw; | |
845 | int status; | |
846 | ||
847 | status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj)); | |
848 | if (status) | |
849 | return status; | |
850 | *obj = ntohl(raw); | |
851 | return 0; | |
852 | } | |
853 | ||
bd8100e7 AG |
854 | int |
855 | xdr_encode_word(struct xdr_buf *buf, int base, u32 obj) | |
856 | { | |
857 | u32 raw = htonl(obj); | |
858 | ||
859 | return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj)); | |
860 | } | |
861 | ||
1da177e4 LT |
862 | /* If the netobj starting offset bytes from the start of xdr_buf is contained |
863 | * entirely in the head or the tail, set object to point to it; otherwise | |
864 | * try to find space for it at the end of the tail, copy it there, and | |
865 | * set obj to point to it. */ | |
866 | int | |
867 | xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, int offset) | |
868 | { | |
869 | u32 tail_offset = buf->head[0].iov_len + buf->page_len; | |
870 | u32 obj_end_offset; | |
871 | ||
bd8100e7 | 872 | if (xdr_decode_word(buf, offset, &obj->len)) |
1da177e4 LT |
873 | goto out; |
874 | obj_end_offset = offset + 4 + obj->len; | |
875 | ||
876 | if (obj_end_offset <= buf->head[0].iov_len) { | |
877 | /* The obj is contained entirely in the head: */ | |
878 | obj->data = buf->head[0].iov_base + offset + 4; | |
879 | } else if (offset + 4 >= tail_offset) { | |
880 | if (obj_end_offset - tail_offset | |
881 | > buf->tail[0].iov_len) | |
882 | goto out; | |
883 | /* The obj is contained entirely in the tail: */ | |
884 | obj->data = buf->tail[0].iov_base | |
885 | + offset - tail_offset + 4; | |
886 | } else { | |
887 | /* use end of tail as storage for obj: | |
888 | * (We don't copy to the beginning because then we'd have | |
889 | * to worry about doing a potentially overlapping copy. | |
890 | * This assumes the object is at most half the length of the | |
891 | * tail.) */ | |
892 | if (obj->len > buf->tail[0].iov_len) | |
893 | goto out; | |
894 | obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len - | |
895 | obj->len; | |
896 | if (read_bytes_from_xdr_buf(buf, offset + 4, | |
897 | obj->data, obj->len)) | |
898 | goto out; | |
899 | ||
900 | } | |
901 | return 0; | |
902 | out: | |
903 | return -1; | |
904 | } | |
bd8100e7 AG |
905 | |
906 | /* Returns 0 on success, or else a negative error code. */ | |
907 | static int | |
908 | xdr_xcode_array2(struct xdr_buf *buf, unsigned int base, | |
909 | struct xdr_array2_desc *desc, int encode) | |
910 | { | |
911 | char *elem = NULL, *c; | |
912 | unsigned int copied = 0, todo, avail_here; | |
913 | struct page **ppages = NULL; | |
914 | int err; | |
915 | ||
916 | if (encode) { | |
917 | if (xdr_encode_word(buf, base, desc->array_len) != 0) | |
918 | return -EINVAL; | |
919 | } else { | |
920 | if (xdr_decode_word(buf, base, &desc->array_len) != 0 || | |
58fcb8df | 921 | desc->array_len > desc->array_maxlen || |
bd8100e7 AG |
922 | (unsigned long) base + 4 + desc->array_len * |
923 | desc->elem_size > buf->len) | |
924 | return -EINVAL; | |
925 | } | |
926 | base += 4; | |
927 | ||
928 | if (!desc->xcode) | |
929 | return 0; | |
930 | ||
931 | todo = desc->array_len * desc->elem_size; | |
932 | ||
933 | /* process head */ | |
934 | if (todo && base < buf->head->iov_len) { | |
935 | c = buf->head->iov_base + base; | |
936 | avail_here = min_t(unsigned int, todo, | |
937 | buf->head->iov_len - base); | |
938 | todo -= avail_here; | |
939 | ||
940 | while (avail_here >= desc->elem_size) { | |
941 | err = desc->xcode(desc, c); | |
942 | if (err) | |
943 | goto out; | |
944 | c += desc->elem_size; | |
945 | avail_here -= desc->elem_size; | |
946 | } | |
947 | if (avail_here) { | |
948 | if (!elem) { | |
949 | elem = kmalloc(desc->elem_size, GFP_KERNEL); | |
950 | err = -ENOMEM; | |
951 | if (!elem) | |
952 | goto out; | |
953 | } | |
954 | if (encode) { | |
955 | err = desc->xcode(desc, elem); | |
956 | if (err) | |
957 | goto out; | |
958 | memcpy(c, elem, avail_here); | |
959 | } else | |
960 | memcpy(elem, c, avail_here); | |
961 | copied = avail_here; | |
962 | } | |
963 | base = buf->head->iov_len; /* align to start of pages */ | |
964 | } | |
965 | ||
966 | /* process pages array */ | |
967 | base -= buf->head->iov_len; | |
968 | if (todo && base < buf->page_len) { | |
969 | unsigned int avail_page; | |
970 | ||
971 | avail_here = min(todo, buf->page_len - base); | |
972 | todo -= avail_here; | |
973 | ||
974 | base += buf->page_base; | |
975 | ppages = buf->pages + (base >> PAGE_CACHE_SHIFT); | |
976 | base &= ~PAGE_CACHE_MASK; | |
977 | avail_page = min_t(unsigned int, PAGE_CACHE_SIZE - base, | |
978 | avail_here); | |
979 | c = kmap(*ppages) + base; | |
980 | ||
981 | while (avail_here) { | |
982 | avail_here -= avail_page; | |
983 | if (copied || avail_page < desc->elem_size) { | |
984 | unsigned int l = min(avail_page, | |
985 | desc->elem_size - copied); | |
986 | if (!elem) { | |
987 | elem = kmalloc(desc->elem_size, | |
988 | GFP_KERNEL); | |
989 | err = -ENOMEM; | |
990 | if (!elem) | |
991 | goto out; | |
992 | } | |
993 | if (encode) { | |
994 | if (!copied) { | |
995 | err = desc->xcode(desc, elem); | |
996 | if (err) | |
997 | goto out; | |
998 | } | |
999 | memcpy(c, elem + copied, l); | |
1000 | copied += l; | |
1001 | if (copied == desc->elem_size) | |
1002 | copied = 0; | |
1003 | } else { | |
1004 | memcpy(elem + copied, c, l); | |
1005 | copied += l; | |
1006 | if (copied == desc->elem_size) { | |
1007 | err = desc->xcode(desc, elem); | |
1008 | if (err) | |
1009 | goto out; | |
1010 | copied = 0; | |
1011 | } | |
1012 | } | |
1013 | avail_page -= l; | |
1014 | c += l; | |
1015 | } | |
1016 | while (avail_page >= desc->elem_size) { | |
1017 | err = desc->xcode(desc, c); | |
1018 | if (err) | |
1019 | goto out; | |
1020 | c += desc->elem_size; | |
1021 | avail_page -= desc->elem_size; | |
1022 | } | |
1023 | if (avail_page) { | |
1024 | unsigned int l = min(avail_page, | |
1025 | desc->elem_size - copied); | |
1026 | if (!elem) { | |
1027 | elem = kmalloc(desc->elem_size, | |
1028 | GFP_KERNEL); | |
1029 | err = -ENOMEM; | |
1030 | if (!elem) | |
1031 | goto out; | |
1032 | } | |
1033 | if (encode) { | |
1034 | if (!copied) { | |
1035 | err = desc->xcode(desc, elem); | |
1036 | if (err) | |
1037 | goto out; | |
1038 | } | |
1039 | memcpy(c, elem + copied, l); | |
1040 | copied += l; | |
1041 | if (copied == desc->elem_size) | |
1042 | copied = 0; | |
1043 | } else { | |
1044 | memcpy(elem + copied, c, l); | |
1045 | copied += l; | |
1046 | if (copied == desc->elem_size) { | |
1047 | err = desc->xcode(desc, elem); | |
1048 | if (err) | |
1049 | goto out; | |
1050 | copied = 0; | |
1051 | } | |
1052 | } | |
1053 | } | |
1054 | if (avail_here) { | |
1055 | kunmap(*ppages); | |
1056 | ppages++; | |
1057 | c = kmap(*ppages); | |
1058 | } | |
1059 | ||
1060 | avail_page = min(avail_here, | |
1061 | (unsigned int) PAGE_CACHE_SIZE); | |
1062 | } | |
1063 | base = buf->page_len; /* align to start of tail */ | |
1064 | } | |
1065 | ||
1066 | /* process tail */ | |
1067 | base -= buf->page_len; | |
1068 | if (todo) { | |
1069 | c = buf->tail->iov_base + base; | |
1070 | if (copied) { | |
1071 | unsigned int l = desc->elem_size - copied; | |
1072 | ||
1073 | if (encode) | |
1074 | memcpy(c, elem + copied, l); | |
1075 | else { | |
1076 | memcpy(elem + copied, c, l); | |
1077 | err = desc->xcode(desc, elem); | |
1078 | if (err) | |
1079 | goto out; | |
1080 | } | |
1081 | todo -= l; | |
1082 | c += l; | |
1083 | } | |
1084 | while (todo) { | |
1085 | err = desc->xcode(desc, c); | |
1086 | if (err) | |
1087 | goto out; | |
1088 | c += desc->elem_size; | |
1089 | todo -= desc->elem_size; | |
1090 | } | |
1091 | } | |
1092 | err = 0; | |
1093 | ||
1094 | out: | |
1095 | if (elem) | |
1096 | kfree(elem); | |
1097 | if (ppages) | |
1098 | kunmap(*ppages); | |
1099 | return err; | |
1100 | } | |
1101 | ||
1102 | int | |
1103 | xdr_decode_array2(struct xdr_buf *buf, unsigned int base, | |
1104 | struct xdr_array2_desc *desc) | |
1105 | { | |
1106 | if (base >= buf->len) | |
1107 | return -EINVAL; | |
1108 | ||
1109 | return xdr_xcode_array2(buf, base, desc, 0); | |
1110 | } | |
1111 | ||
1112 | int | |
1113 | xdr_encode_array2(struct xdr_buf *buf, unsigned int base, | |
1114 | struct xdr_array2_desc *desc) | |
1115 | { | |
1116 | if ((unsigned long) base + 4 + desc->array_len * desc->elem_size > | |
1117 | buf->head->iov_len + buf->page_len + buf->tail->iov_len) | |
1118 | return -EINVAL; | |
1119 | ||
1120 | return xdr_xcode_array2(buf, base, desc, 1); | |
1121 | } |