xref: /freebsd/sys/kern/subr_uio.c (revision a0ee8cc6) 
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  * Copyright (c) 2014 The FreeBSD Foundation
11  *
12  * Portions of this software were developed by Konstantin Belousov
13  * under sponsorship from the FreeBSD Foundation.
14  *
15  * Redistribution and use in source and binary forms, with or without
16  * modification, are permitted provided that the following conditions
17  * are met:
18  * 1. Redistributions of source code must retain the above copyright
19  *    notice, this list of conditions and the following disclaimer.
20  * 2. Redistributions in binary form must reproduce the above copyright
21  *    notice, this list of conditions and the following disclaimer in the
22  *    documentation and/or other materials provided with the distribution.
23  * 4. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  *
39  *	@(#)kern_subr.c	8.3 (Berkeley) 1/21/94
40  */
41 
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD$");
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/limits.h>
49 #include <sys/lock.h>
50 #include <sys/mman.h>
51 #include <sys/proc.h>
52 #include <sys/resourcevar.h>
53 #include <sys/rwlock.h>
54 #include <sys/sched.h>
55 #include <sys/sysctl.h>
56 #include <sys/vnode.h>
57 
58 #include <vm/vm.h>
59 #include <vm/vm_param.h>
60 #include <vm/vm_extern.h>
61 #include <vm/vm_page.h>
62 #include <vm/vm_pageout.h>
63 #include <vm/vm_map.h>
64 
65 #include <machine/bus.h>
66 
67 SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, UIO_MAXIOV,
68 	"Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
69 
70 static int uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault);
71 
72 int
73 copyin_nofault(const void *udaddr, void *kaddr, size_t len)
74 {
75 	int error, save;
76 
77 	save = vm_fault_disable_pagefaults();
78 	error = copyin(udaddr, kaddr, len);
79 	vm_fault_enable_pagefaults(save);
80 	return (error);
81 }
82 
83 int
84 copyout_nofault(const void *kaddr, void *udaddr, size_t len)
85 {
86 	int error, save;
87 
88 	save = vm_fault_disable_pagefaults();
89 	error = copyout(kaddr, udaddr, len);
90 	vm_fault_enable_pagefaults(save);
91 	return (error);
92 }
93 
94 #define	PHYS_PAGE_COUNT(len)	(howmany(len, PAGE_SIZE) + 1)
95 
96 int
97 physcopyin(void *src, vm_paddr_t dst, size_t len)
98 {
99 	vm_page_t m[PHYS_PAGE_COUNT(len)];
100 	struct iovec iov[1];
101 	struct uio uio;
102 	int i;
103 
104 	iov[0].iov_base = src;
105 	iov[0].iov_len = len;
106 	uio.uio_iov = iov;
107 	uio.uio_iovcnt = 1;
108 	uio.uio_offset = 0;
109 	uio.uio_resid = len;
110 	uio.uio_segflg = UIO_SYSSPACE;
111 	uio.uio_rw = UIO_WRITE;
112 	for (i = 0; i < PHYS_PAGE_COUNT(len); i++, dst += PAGE_SIZE)
113 		m[i] = PHYS_TO_VM_PAGE(dst);
114 	return (uiomove_fromphys(m, dst & PAGE_MASK, len, &uio));
115 }
116 
117 int
118 physcopyout(vm_paddr_t src, void *dst, size_t len)
119 {
120 	vm_page_t m[PHYS_PAGE_COUNT(len)];
121 	struct iovec iov[1];
122 	struct uio uio;
123 	int i;
124 
125 	iov[0].iov_base = dst;
126 	iov[0].iov_len = len;
127 	uio.uio_iov = iov;
128 	uio.uio_iovcnt = 1;
129 	uio.uio_offset = 0;
130 	uio.uio_resid = len;
131 	uio.uio_segflg = UIO_SYSSPACE;
132 	uio.uio_rw = UIO_READ;
133 	for (i = 0; i < PHYS_PAGE_COUNT(len); i++, src += PAGE_SIZE)
134 		m[i] = PHYS_TO_VM_PAGE(src);
135 	return (uiomove_fromphys(m, src & PAGE_MASK, len, &uio));
136 }
137 
138 #undef PHYS_PAGE_COUNT
139 
140 int
141 physcopyin_vlist(bus_dma_segment_t *src, off_t offset, vm_paddr_t dst,
142     size_t len)
143 {
144 	size_t seg_len;
145 	int error;
146 
147 	error = 0;
148 	while (offset >= src->ds_len) {
149 		offset -= src->ds_len;
150 		src++;
151 	}
152 
153 	while (len > 0 && error == 0) {
154 		seg_len = MIN(src->ds_len - offset, len);
155 		error = physcopyin((void *)(uintptr_t)(src->ds_addr + offset),
156 		    dst, seg_len);
157 		offset = 0;
158 		src++;
159 		len -= seg_len;
160 		dst += seg_len;
161 	}
162 
163 	return (error);
164 }
165 
166 int
167 physcopyout_vlist(vm_paddr_t src, bus_dma_segment_t *dst, off_t offset,
168     size_t len)
169 {
170 	size_t seg_len;
171 	int error;
172 
173 	error = 0;
174 	while (offset >= dst->ds_len) {
175 		offset -= dst->ds_len;
176 		dst++;
177 	}
178 
179 	while (len > 0 && error == 0) {
180 		seg_len = MIN(dst->ds_len - offset, len);
181 		error = physcopyout(src, (void *)(uintptr_t)(dst->ds_addr +
182 		    offset), seg_len);
183 		offset = 0;
184 		dst++;
185 		len -= seg_len;
186 		src += seg_len;
187 	}
188 
189 	return (error);
190 }
191 
192 int
193 uiomove(void *cp, int n, struct uio *uio)
194 {
195 
196 	return (uiomove_faultflag(cp, n, uio, 0));
197 }
198 
199 int
200 uiomove_nofault(void *cp, int n, struct uio *uio)
201 {
202 
203 	return (uiomove_faultflag(cp, n, uio, 1));
204 }
205 
206 static int
207 uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault)
208 {
209 	struct thread *td;
210 	struct iovec *iov;
211 	size_t cnt;
212 	int error, newflags, save;
213 
214 	td = curthread;
215 	error = 0;
216 
217 	KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
218 	    ("uiomove: mode"));
219 	KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == td,
220 	    ("uiomove proc"));
221 	if (!nofault)
222 		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
223 		    "Calling uiomove()");
224 
225 	/* XXX does it make a sense to set TDP_DEADLKTREAT for UIO_SYSSPACE ? */
226 	newflags = TDP_DEADLKTREAT;
227 	if (uio->uio_segflg == UIO_USERSPACE && nofault) {
228 		/*
229 		 * Fail if a non-spurious page fault occurs.
230 		 */
231 		newflags |= TDP_NOFAULTING | TDP_RESETSPUR;
232 	}
233 	save = curthread_pflags_set(newflags);
234 
235 	while (n > 0 && uio->uio_resid) {
236 		iov = uio->uio_iov;
237 		cnt = iov->iov_len;
238 		if (cnt == 0) {
239 			uio->uio_iov++;
240 			uio->uio_iovcnt--;
241 			continue;
242 		}
243 		if (cnt > n)
244 			cnt = n;
245 
246 		switch (uio->uio_segflg) {
247 
248 		case UIO_USERSPACE:
249 			maybe_yield();
250 			if (uio->uio_rw == UIO_READ)
251 				error = copyout(cp, iov->iov_base, cnt);
252 			else
253 				error = copyin(iov->iov_base, cp, cnt);
254 			if (error)
255 				goto out;
256 			break;
257 
258 		case UIO_SYSSPACE:
259 			if (uio->uio_rw == UIO_READ)
260 				bcopy(cp, iov->iov_base, cnt);
261 			else
262 				bcopy(iov->iov_base, cp, cnt);
263 			break;
264 		case UIO_NOCOPY:
265 			break;
266 		}
267 		iov->iov_base = (char *)iov->iov_base + cnt;
268 		iov->iov_len -= cnt;
269 		uio->uio_resid -= cnt;
270 		uio->uio_offset += cnt;
271 		cp = (char *)cp + cnt;
272 		n -= cnt;
273 	}
274 out:
275 	curthread_pflags_restore(save);
276 	return (error);
277 }
278 
279 /*
280  * Wrapper for uiomove() that validates the arguments against a known-good
281  * kernel buffer.  Currently, uiomove accepts a signed (n) argument, which
282  * is almost definitely a bad thing, so we catch that here as well.  We
283  * return a runtime failure, but it might be desirable to generate a runtime
284  * assertion failure instead.
285  */
286 int
287 uiomove_frombuf(void *buf, int buflen, struct uio *uio)
288 {
289 	size_t offset, n;
290 
291 	if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
292 	    (offset = uio->uio_offset) != uio->uio_offset)
293 		return (EINVAL);
294 	if (buflen <= 0 || offset >= buflen)
295 		return (0);
296 	if ((n = buflen - offset) > IOSIZE_MAX)
297 		return (EINVAL);
298 	return (uiomove((char *)buf + offset, n, uio));
299 }
300 
301 /*
302  * Give next character to user as result of read.
303  */
304 int
305 ureadc(int c, struct uio *uio)
306 {
307 	struct iovec *iov;
308 	char *iov_base;
309 
310 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
311 	    "Calling ureadc()");
312 
313 again:
314 	if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
315 		panic("ureadc");
316 	iov = uio->uio_iov;
317 	if (iov->iov_len == 0) {
318 		uio->uio_iovcnt--;
319 		uio->uio_iov++;
320 		goto again;
321 	}
322 	switch (uio->uio_segflg) {
323 
324 	case UIO_USERSPACE:
325 		if (subyte(iov->iov_base, c) < 0)
326 			return (EFAULT);
327 		break;
328 
329 	case UIO_SYSSPACE:
330 		iov_base = iov->iov_base;
331 		*iov_base = c;
332 		break;
333 
334 	case UIO_NOCOPY:
335 		break;
336 	}
337 	iov->iov_base = (char *)iov->iov_base + 1;
338 	iov->iov_len--;
339 	uio->uio_resid--;
340 	uio->uio_offset++;
341 	return (0);
342 }
343 
344 int
345 copyinfrom(const void * __restrict src, void * __restrict dst, size_t len,
346     int seg)
347 {
348 	int error = 0;
349 
350 	switch (seg) {
351 	case UIO_USERSPACE:
352 		error = copyin(src, dst, len);
353 		break;
354 	case UIO_SYSSPACE:
355 		bcopy(src, dst, len);
356 		break;
357 	default:
358 		panic("copyinfrom: bad seg %d\n", seg);
359 	}
360 	return (error);
361 }
362 
363 int
364 copyinstrfrom(const void * __restrict src, void * __restrict dst, size_t len,
365     size_t * __restrict copied, int seg)
366 {
367 	int error = 0;
368 
369 	switch (seg) {
370 	case UIO_USERSPACE:
371 		error = copyinstr(src, dst, len, copied);
372 		break;
373 	case UIO_SYSSPACE:
374 		error = copystr(src, dst, len, copied);
375 		break;
376 	default:
377 		panic("copyinstrfrom: bad seg %d\n", seg);
378 	}
379 	return (error);
380 }
381 
382 int
383 copyiniov(const struct iovec *iovp, u_int iovcnt, struct iovec **iov, int error)
384 {
385 	u_int iovlen;
386 
387 	*iov = NULL;
388 	if (iovcnt > UIO_MAXIOV)
389 		return (error);
390 	iovlen = iovcnt * sizeof (struct iovec);
391 	*iov = malloc(iovlen, M_IOV, M_WAITOK);
392 	error = copyin(iovp, *iov, iovlen);
393 	if (error) {
394 		free(*iov, M_IOV);
395 		*iov = NULL;
396 	}
397 	return (error);
398 }
399 
400 int
401 copyinuio(const struct iovec *iovp, u_int iovcnt, struct uio **uiop)
402 {
403 	struct iovec *iov;
404 	struct uio *uio;
405 	u_int iovlen;
406 	int error, i;
407 
408 	*uiop = NULL;
409 	if (iovcnt > UIO_MAXIOV)
410 		return (EINVAL);
411 	iovlen = iovcnt * sizeof (struct iovec);
412 	uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
413 	iov = (struct iovec *)(uio + 1);
414 	error = copyin(iovp, iov, iovlen);
415 	if (error) {
416 		free(uio, M_IOV);
417 		return (error);
418 	}
419 	uio->uio_iov = iov;
420 	uio->uio_iovcnt = iovcnt;
421 	uio->uio_segflg = UIO_USERSPACE;
422 	uio->uio_offset = -1;
423 	uio->uio_resid = 0;
424 	for (i = 0; i < iovcnt; i++) {
425 		if (iov->iov_len > IOSIZE_MAX - uio->uio_resid) {
426 			free(uio, M_IOV);
427 			return (EINVAL);
428 		}
429 		uio->uio_resid += iov->iov_len;
430 		iov++;
431 	}
432 	*uiop = uio;
433 	return (0);
434 }
435 
436 struct uio *
437 cloneuio(struct uio *uiop)
438 {
439 	struct uio *uio;
440 	int iovlen;
441 
442 	iovlen = uiop->uio_iovcnt * sizeof (struct iovec);
443 	uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
444 	*uio = *uiop;
445 	uio->uio_iov = (struct iovec *)(uio + 1);
446 	bcopy(uiop->uio_iov, uio->uio_iov, iovlen);
447 	return (uio);
448 }
449 
450 /*
451  * Map some anonymous memory in user space of size sz, rounded up to the page
452  * boundary.
453  */
454 int
455 copyout_map(struct thread *td, vm_offset_t *addr, size_t sz)
456 {
457 	struct vmspace *vms;
458 	int error;
459 	vm_size_t size;
460 
461 	vms = td->td_proc->p_vmspace;
462 
463 	/*
464 	 * Map somewhere after heap in process memory.
465 	 */
466 	*addr = round_page((vm_offset_t)vms->vm_daddr +
467 	    lim_max(td, RLIMIT_DATA));
468 
469 	/* round size up to page boundry */
470 	size = (vm_size_t)round_page(sz);
471 
472 	error = vm_mmap(&vms->vm_map, addr, size, VM_PROT_READ | VM_PROT_WRITE,
473 	    VM_PROT_ALL, MAP_PRIVATE | MAP_ANON, OBJT_DEFAULT, NULL, 0);
474 
475 	return (error);
476 }
477 
478 /*
479  * Unmap memory in user space.
480  */
481 int
482 copyout_unmap(struct thread *td, vm_offset_t addr, size_t sz)
483 {
484 	vm_map_t map;
485 	vm_size_t size;
486 
487 	if (sz == 0)
488 		return (0);
489 
490 	map = &td->td_proc->p_vmspace->vm_map;
491 	size = (vm_size_t)round_page(sz);
492 
493 	if (vm_map_remove(map, addr, addr + size) != KERN_SUCCESS)
494 		return (EINVAL);
495 
496 	return (0);
497 }
498 
499 #ifdef NO_FUEWORD
500 /*
501  * XXXKIB The temporal implementation of fue*() functions which do not
502  * handle usermode -1 properly, mixing it with the fault code.  Keep
503  * this until MD code is written.  Currently sparc64, mips and arm do
504  * not have proper implementation.
505  */
506 
507 int
508 fueword(volatile const void *base, long *val)
509 {
510 	long res;
511 
512 	res = fuword(base);
513 	if (res == -1)
514 		return (-1);
515 	*val = res;
516 	return (0);
517 }
518 
519 int
520 fueword32(volatile const void *base, int32_t *val)
521 {
522 	int32_t res;
523 
524 	res = fuword32(base);
525 	if (res == -1)
526 		return (-1);
527 	*val = res;
528 	return (0);
529 }
530 
531 #ifdef _LP64
532 int
533 fueword64(volatile const void *base, int64_t *val)
534 {
535 	int32_t res;
536 
537 	res = fuword64(base);
538 	if (res == -1)
539 		return (-1);
540 	*val = res;
541 	return (0);
542 }
543 #endif
544 
545 int
546 casueword32(volatile uint32_t *base, uint32_t oldval, uint32_t *oldvalp,
547     uint32_t newval)
548 {
549 	int32_t ov;
550 
551 	ov = casuword32(base, oldval, newval);
552 	if (ov == -1)
553 		return (-1);
554 	*oldvalp = ov;
555 	return (0);
556 }
557 
558 int
559 casueword(volatile u_long *p, u_long oldval, u_long *oldvalp, u_long newval)
560 {
561 	u_long ov;
562 
563 	ov = casuword(p, oldval, newval);
564 	if (ov == -1)
565 		return (-1);
566 	*oldvalp = ov;
567 	return (0);
568 }
569 #else /* NO_FUEWORD */
570 int32_t
571 fuword32(volatile const void *addr)
572 {
573 	int rv;
574 	int32_t val;
575 
576 	rv = fueword32(addr, &val);
577 	return (rv == -1 ? -1 : val);
578 }
579 
580 #ifdef _LP64
581 int64_t
582 fuword64(volatile const void *addr)
583 {
584 	int rv;
585 	int64_t val;
586 
587 	rv = fueword64(addr, &val);
588 	return (rv == -1 ? -1 : val);
589 }
590 #endif /* _LP64 */
591 
592 long
593 fuword(volatile const void *addr)
594 {
595 	long val;
596 	int rv;
597 
598 	rv = fueword(addr, &val);
599 	return (rv == -1 ? -1 : val);
600 }
601 
602 uint32_t
603 casuword32(volatile uint32_t *addr, uint32_t old, uint32_t new)
604 {
605 	int rv;
606 	uint32_t val;
607 
608 	rv = casueword32(addr, old, &val, new);
609 	return (rv == -1 ? -1 : val);
610 }
611 
612 u_long
613 casuword(volatile u_long *addr, u_long old, u_long new)
614 {
615 	int rv;
616 	u_long val;
617 
618 	rv = casueword(addr, old, &val, new);
619 	return (rv == -1 ? -1 : val);
620 }
621 
622 #endif /* NO_FUEWORD */
623