FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_uio.c
1 /*-
2 * Copyright (c) 1982, 1986, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
35 */
36
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD: releng/9.0/sys/kern/subr_uio.c 223889 2011-07-09 15:21:10Z kib $");
39
40 #include "opt_zero.h"
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
45 #include <sys/limits.h>
46 #include <sys/lock.h>
47 #include <sys/mman.h>
48 #include <sys/mutex.h>
49 #include <sys/proc.h>
50 #include <sys/resourcevar.h>
51 #include <sys/sched.h>
52 #include <sys/sysctl.h>
53 #include <sys/vnode.h>
54
55 #include <vm/vm.h>
56 #include <vm/vm_extern.h>
57 #include <vm/vm_page.h>
58 #include <vm/vm_map.h>
59 #ifdef ZERO_COPY_SOCKETS
60 #include <vm/vm_param.h>
61 #include <vm/vm_object.h>
62 #endif
63
64 SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, NULL, UIO_MAXIOV,
65 "Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
66
67 static int uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault);
68
69 #ifdef ZERO_COPY_SOCKETS
70 /* Declared in uipc_socket.c */
71 extern int so_zero_copy_receive;
72
73 /*
74 * Identify the physical page mapped at the given kernel virtual
75 * address. Insert this physical page into the given address space at
76 * the given virtual address, replacing the physical page, if any,
77 * that already exists there.
78 */
79 static int
80 vm_pgmoveco(vm_map_t mapa, vm_offset_t kaddr, vm_offset_t uaddr)
81 {
82 vm_map_t map = mapa;
83 vm_page_t kern_pg, user_pg;
84 vm_object_t uobject;
85 vm_map_entry_t entry;
86 vm_pindex_t upindex;
87 vm_prot_t prot;
88 boolean_t wired;
89
90 KASSERT((uaddr & PAGE_MASK) == 0,
91 ("vm_pgmoveco: uaddr is not page aligned"));
92
93 /*
94 * Herein the physical page is validated and dirtied. It is
95 * unwired in sf_buf_mext().
96 */
97 kern_pg = PHYS_TO_VM_PAGE(vtophys(kaddr));
98 kern_pg->valid = VM_PAGE_BITS_ALL;
99 KASSERT(kern_pg->queue == PQ_NONE && kern_pg->wire_count == 1,
100 ("vm_pgmoveco: kern_pg is not correctly wired"));
101
102 if ((vm_map_lookup(&map, uaddr,
103 VM_PROT_WRITE, &entry, &uobject,
104 &upindex, &prot, &wired)) != KERN_SUCCESS) {
105 return(EFAULT);
106 }
107 VM_OBJECT_LOCK(uobject);
108 retry:
109 if ((user_pg = vm_page_lookup(uobject, upindex)) != NULL) {
110 if (vm_page_sleep_if_busy(user_pg, TRUE, "vm_pgmoveco"))
111 goto retry;
112 vm_page_lock(user_pg);
113 pmap_remove_all(user_pg);
114 vm_page_free(user_pg);
115 vm_page_unlock(user_pg);
116 } else {
117 /*
118 * Even if a physical page does not exist in the
119 * object chain's first object, a physical page from a
120 * backing object may be mapped read only.
121 */
122 if (uobject->backing_object != NULL)
123 pmap_remove(map->pmap, uaddr, uaddr + PAGE_SIZE);
124 }
125 vm_page_insert(kern_pg, uobject, upindex);
126 vm_page_dirty(kern_pg);
127 VM_OBJECT_UNLOCK(uobject);
128 vm_map_lookup_done(map, entry);
129 return(KERN_SUCCESS);
130 }
131 #endif /* ZERO_COPY_SOCKETS */
132
133 int
134 copyin_nofault(const void *udaddr, void *kaddr, size_t len)
135 {
136 int error, save;
137
138 save = vm_fault_disable_pagefaults();
139 error = copyin(udaddr, kaddr, len);
140 vm_fault_enable_pagefaults(save);
141 return (error);
142 }
143
144 int
145 copyout_nofault(const void *kaddr, void *udaddr, size_t len)
146 {
147 int error, save;
148
149 save = vm_fault_disable_pagefaults();
150 error = copyout(kaddr, udaddr, len);
151 vm_fault_enable_pagefaults(save);
152 return (error);
153 }
154
155 int
156 uiomove(void *cp, int n, struct uio *uio)
157 {
158
159 return (uiomove_faultflag(cp, n, uio, 0));
160 }
161
162 int
163 uiomove_nofault(void *cp, int n, struct uio *uio)
164 {
165
166 return (uiomove_faultflag(cp, n, uio, 1));
167 }
168
169 static int
170 uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault)
171 {
172 struct thread *td;
173 struct iovec *iov;
174 u_int cnt;
175 int error, newflags, save;
176
177 td = curthread;
178 error = 0;
179
180 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
181 ("uiomove: mode"));
182 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == td,
183 ("uiomove proc"));
184 if (!nofault)
185 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
186 "Calling uiomove()");
187
188 /* XXX does it make a sense to set TDP_DEADLKTREAT for UIO_SYSSPACE ? */
189 newflags = TDP_DEADLKTREAT;
190 if (uio->uio_segflg == UIO_USERSPACE && nofault)
191 newflags |= TDP_NOFAULTING;
192 save = curthread_pflags_set(newflags);
193
194 while (n > 0 && uio->uio_resid) {
195 iov = uio->uio_iov;
196 cnt = iov->iov_len;
197 if (cnt == 0) {
198 uio->uio_iov++;
199 uio->uio_iovcnt--;
200 continue;
201 }
202 if (cnt > n)
203 cnt = n;
204
205 switch (uio->uio_segflg) {
206
207 case UIO_USERSPACE:
208 maybe_yield();
209 if (uio->uio_rw == UIO_READ)
210 error = copyout(cp, iov->iov_base, cnt);
211 else
212 error = copyin(iov->iov_base, cp, cnt);
213 if (error)
214 goto out;
215 break;
216
217 case UIO_SYSSPACE:
218 if (uio->uio_rw == UIO_READ)
219 bcopy(cp, iov->iov_base, cnt);
220 else
221 bcopy(iov->iov_base, cp, cnt);
222 break;
223 case UIO_NOCOPY:
224 break;
225 }
226 iov->iov_base = (char *)iov->iov_base + cnt;
227 iov->iov_len -= cnt;
228 uio->uio_resid -= cnt;
229 uio->uio_offset += cnt;
230 cp = (char *)cp + cnt;
231 n -= cnt;
232 }
233 out:
234 curthread_pflags_restore(save);
235 return (error);
236 }
237
238 /*
239 * Wrapper for uiomove() that validates the arguments against a known-good
240 * kernel buffer. Currently, uiomove accepts a signed (n) argument, which
241 * is almost definitely a bad thing, so we catch that here as well. We
242 * return a runtime failure, but it might be desirable to generate a runtime
243 * assertion failure instead.
244 */
245 int
246 uiomove_frombuf(void *buf, int buflen, struct uio *uio)
247 {
248 unsigned int offset, n;
249
250 if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
251 (offset = uio->uio_offset) != uio->uio_offset)
252 return (EINVAL);
253 if (buflen <= 0 || offset >= buflen)
254 return (0);
255 if ((n = buflen - offset) > INT_MAX)
256 return (EINVAL);
257 return (uiomove((char *)buf + offset, n, uio));
258 }
259
260 #ifdef ZERO_COPY_SOCKETS
261 /*
262 * Experimental support for zero-copy I/O
263 */
264 static int
265 userspaceco(void *cp, u_int cnt, struct uio *uio, int disposable)
266 {
267 struct iovec *iov;
268 int error;
269
270 iov = uio->uio_iov;
271 if (uio->uio_rw == UIO_READ) {
272 if ((so_zero_copy_receive != 0)
273 && ((cnt & PAGE_MASK) == 0)
274 && ((((intptr_t) iov->iov_base) & PAGE_MASK) == 0)
275 && ((uio->uio_offset & PAGE_MASK) == 0)
276 && ((((intptr_t) cp) & PAGE_MASK) == 0)
277 && (disposable != 0)) {
278 /* SOCKET: use page-trading */
279 /*
280 * We only want to call vm_pgmoveco() on
281 * disposeable pages, since it gives the
282 * kernel page to the userland process.
283 */
284 error = vm_pgmoveco(&curproc->p_vmspace->vm_map,
285 (vm_offset_t)cp, (vm_offset_t)iov->iov_base);
286
287 /*
288 * If we get an error back, attempt
289 * to use copyout() instead. The
290 * disposable page should be freed
291 * automatically if we weren't able to move
292 * it into userland.
293 */
294 if (error != 0)
295 error = copyout(cp, iov->iov_base, cnt);
296 } else {
297 error = copyout(cp, iov->iov_base, cnt);
298 }
299 } else {
300 error = copyin(iov->iov_base, cp, cnt);
301 }
302 return (error);
303 }
304
305 int
306 uiomoveco(void *cp, int n, struct uio *uio, int disposable)
307 {
308 struct iovec *iov;
309 u_int cnt;
310 int error;
311
312 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
313 ("uiomoveco: mode"));
314 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
315 ("uiomoveco proc"));
316
317 while (n > 0 && uio->uio_resid) {
318 iov = uio->uio_iov;
319 cnt = iov->iov_len;
320 if (cnt == 0) {
321 uio->uio_iov++;
322 uio->uio_iovcnt--;
323 continue;
324 }
325 if (cnt > n)
326 cnt = n;
327
328 switch (uio->uio_segflg) {
329
330 case UIO_USERSPACE:
331 maybe_yield();
332 error = userspaceco(cp, cnt, uio, disposable);
333 if (error)
334 return (error);
335 break;
336
337 case UIO_SYSSPACE:
338 if (uio->uio_rw == UIO_READ)
339 bcopy(cp, iov->iov_base, cnt);
340 else
341 bcopy(iov->iov_base, cp, cnt);
342 break;
343 case UIO_NOCOPY:
344 break;
345 }
346 iov->iov_base = (char *)iov->iov_base + cnt;
347 iov->iov_len -= cnt;
348 uio->uio_resid -= cnt;
349 uio->uio_offset += cnt;
350 cp = (char *)cp + cnt;
351 n -= cnt;
352 }
353 return (0);
354 }
355 #endif /* ZERO_COPY_SOCKETS */
356
357 /*
358 * Give next character to user as result of read.
359 */
360 int
361 ureadc(int c, struct uio *uio)
362 {
363 struct iovec *iov;
364 char *iov_base;
365
366 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
367 "Calling ureadc()");
368
369 again:
370 if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
371 panic("ureadc");
372 iov = uio->uio_iov;
373 if (iov->iov_len == 0) {
374 uio->uio_iovcnt--;
375 uio->uio_iov++;
376 goto again;
377 }
378 switch (uio->uio_segflg) {
379
380 case UIO_USERSPACE:
381 if (subyte(iov->iov_base, c) < 0)
382 return (EFAULT);
383 break;
384
385 case UIO_SYSSPACE:
386 iov_base = iov->iov_base;
387 *iov_base = c;
388 iov->iov_base = iov_base;
389 break;
390
391 case UIO_NOCOPY:
392 break;
393 }
394 iov->iov_base = (char *)iov->iov_base + 1;
395 iov->iov_len--;
396 uio->uio_resid--;
397 uio->uio_offset++;
398 return (0);
399 }
400
401 int
402 copyinfrom(const void * __restrict src, void * __restrict dst, size_t len,
403 int seg)
404 {
405 int error = 0;
406
407 switch (seg) {
408 case UIO_USERSPACE:
409 error = copyin(src, dst, len);
410 break;
411 case UIO_SYSSPACE:
412 bcopy(src, dst, len);
413 break;
414 default:
415 panic("copyinfrom: bad seg %d\n", seg);
416 }
417 return (error);
418 }
419
420 int
421 copyinstrfrom(const void * __restrict src, void * __restrict dst, size_t len,
422 size_t * __restrict copied, int seg)
423 {
424 int error = 0;
425
426 switch (seg) {
427 case UIO_USERSPACE:
428 error = copyinstr(src, dst, len, copied);
429 break;
430 case UIO_SYSSPACE:
431 error = copystr(src, dst, len, copied);
432 break;
433 default:
434 panic("copyinstrfrom: bad seg %d\n", seg);
435 }
436 return (error);
437 }
438
439 int
440 copyiniov(struct iovec *iovp, u_int iovcnt, struct iovec **iov, int error)
441 {
442 u_int iovlen;
443
444 *iov = NULL;
445 if (iovcnt > UIO_MAXIOV)
446 return (error);
447 iovlen = iovcnt * sizeof (struct iovec);
448 *iov = malloc(iovlen, M_IOV, M_WAITOK);
449 error = copyin(iovp, *iov, iovlen);
450 if (error) {
451 free(*iov, M_IOV);
452 *iov = NULL;
453 }
454 return (error);
455 }
456
457 int
458 copyinuio(struct iovec *iovp, u_int iovcnt, struct uio **uiop)
459 {
460 struct iovec *iov;
461 struct uio *uio;
462 u_int iovlen;
463 int error, i;
464
465 *uiop = NULL;
466 if (iovcnt > UIO_MAXIOV)
467 return (EINVAL);
468 iovlen = iovcnt * sizeof (struct iovec);
469 uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
470 iov = (struct iovec *)(uio + 1);
471 error = copyin(iovp, iov, iovlen);
472 if (error) {
473 free(uio, M_IOV);
474 return (error);
475 }
476 uio->uio_iov = iov;
477 uio->uio_iovcnt = iovcnt;
478 uio->uio_segflg = UIO_USERSPACE;
479 uio->uio_offset = -1;
480 uio->uio_resid = 0;
481 for (i = 0; i < iovcnt; i++) {
482 if (iov->iov_len > INT_MAX - uio->uio_resid) {
483 free(uio, M_IOV);
484 return (EINVAL);
485 }
486 uio->uio_resid += iov->iov_len;
487 iov++;
488 }
489 *uiop = uio;
490 return (0);
491 }
492
493 struct uio *
494 cloneuio(struct uio *uiop)
495 {
496 struct uio *uio;
497 int iovlen;
498
499 iovlen = uiop->uio_iovcnt * sizeof (struct iovec);
500 uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
501 *uio = *uiop;
502 uio->uio_iov = (struct iovec *)(uio + 1);
503 bcopy(uiop->uio_iov, uio->uio_iov, iovlen);
504 return (uio);
505 }
506
507 /*
508 * Map some anonymous memory in user space of size sz, rounded up to the page
509 * boundary.
510 */
511 int
512 copyout_map(struct thread *td, vm_offset_t *addr, size_t sz)
513 {
514 struct vmspace *vms;
515 int error;
516 vm_size_t size;
517
518 vms = td->td_proc->p_vmspace;
519
520 /*
521 * Map somewhere after heap in process memory.
522 */
523 PROC_LOCK(td->td_proc);
524 *addr = round_page((vm_offset_t)vms->vm_daddr +
525 lim_max(td->td_proc, RLIMIT_DATA));
526 PROC_UNLOCK(td->td_proc);
527
528 /* round size up to page boundry */
529 size = (vm_size_t)round_page(sz);
530
531 error = vm_mmap(&vms->vm_map, addr, size, PROT_READ | PROT_WRITE,
532 VM_PROT_ALL, MAP_PRIVATE | MAP_ANON, OBJT_DEFAULT, NULL, 0);
533
534 return (error);
535 }
536
537 /*
538 * Unmap memory in user space.
539 */
540 int
541 copyout_unmap(struct thread *td, vm_offset_t addr, size_t sz)
542 {
543 vm_map_t map;
544 vm_size_t size;
545
546 if (sz == 0)
547 return (0);
548
549 map = &td->td_proc->p_vmspace->vm_map;
550 size = (vm_size_t)round_page(sz);
551
552 if (vm_map_remove(map, addr, addr + size) != KERN_SUCCESS)
553 return (EINVAL);
554
555 return (0);
556 }
Cache object: 7ce804c2bf82f6db55fbeea47c28a0b4
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