subr_uio.c revision 274648 
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: stable/10/sys/kern/subr_uio.c 274648 2014-11-18 12:53:32Z kib $");
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
65SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, UIO_MAXIOV,
66	"Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
67
68static int uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault);
69
70int
71copyin_nofault(const void *udaddr, void *kaddr, size_t len)
72{
73	int error, save;
74
75	save = vm_fault_disable_pagefaults();
76	error = copyin(udaddr, kaddr, len);
77	vm_fault_enable_pagefaults(save);
78	return (error);
79}
80
81int
82copyout_nofault(const void *kaddr, void *udaddr, size_t len)
83{
84	int error, save;
85
86	save = vm_fault_disable_pagefaults();
87	error = copyout(kaddr, udaddr, len);
88	vm_fault_enable_pagefaults(save);
89	return (error);
90}
91
92#define	PHYS_PAGE_COUNT(len)	(howmany(len, PAGE_SIZE) + 1)
93
94int
95physcopyin(void *src, vm_paddr_t dst, size_t len)
96{
97	vm_page_t m[PHYS_PAGE_COUNT(len)];
98	struct iovec iov[1];
99	struct uio uio;
100	int i;
101
102	iov[0].iov_base = src;
103	iov[0].iov_len = len;
104	uio.uio_iov = iov;
105	uio.uio_iovcnt = 1;
106	uio.uio_offset = 0;
107	uio.uio_resid = len;
108	uio.uio_segflg = UIO_SYSSPACE;
109	uio.uio_rw = UIO_WRITE;
110	for (i = 0; i < PHYS_PAGE_COUNT(len); i++, dst += PAGE_SIZE)
111		m[i] = PHYS_TO_VM_PAGE(dst);
112	return (uiomove_fromphys(m, dst & PAGE_MASK, len, &uio));
113}
114
115int
116physcopyout(vm_paddr_t src, void *dst, size_t len)
117{
118	vm_page_t m[PHYS_PAGE_COUNT(len)];
119	struct iovec iov[1];
120	struct uio uio;
121	int i;
122
123	iov[0].iov_base = dst;
124	iov[0].iov_len = len;
125	uio.uio_iov = iov;
126	uio.uio_iovcnt = 1;
127	uio.uio_offset = 0;
128	uio.uio_resid = len;
129	uio.uio_segflg = UIO_SYSSPACE;
130	uio.uio_rw = UIO_READ;
131	for (i = 0; i < PHYS_PAGE_COUNT(len); i++, src += PAGE_SIZE)
132		m[i] = PHYS_TO_VM_PAGE(src);
133	return (uiomove_fromphys(m, src & PAGE_MASK, len, &uio));
134}
135
136#undef PHYS_PAGE_COUNT
137
138int
139uiomove(void *cp, int n, struct uio *uio)
140{
141
142	return (uiomove_faultflag(cp, n, uio, 0));
143}
144
145int
146uiomove_nofault(void *cp, int n, struct uio *uio)
147{
148
149	return (uiomove_faultflag(cp, n, uio, 1));
150}
151
152static int
153uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault)
154{
155	struct thread *td;
156	struct iovec *iov;
157	size_t cnt;
158	int error, newflags, save;
159
160	td = curthread;
161	error = 0;
162
163	KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
164	    ("uiomove: mode"));
165	KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == td,
166	    ("uiomove proc"));
167	if (!nofault)
168		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
169		    "Calling uiomove()");
170
171	/* XXX does it make a sense to set TDP_DEADLKTREAT for UIO_SYSSPACE ? */
172	newflags = TDP_DEADLKTREAT;
173	if (uio->uio_segflg == UIO_USERSPACE && nofault) {
174		/*
175		 * Fail if a non-spurious page fault occurs.
176		 */
177		newflags |= TDP_NOFAULTING | TDP_RESETSPUR;
178	}
179	save = curthread_pflags_set(newflags);
180
181	while (n > 0 && uio->uio_resid) {
182		iov = uio->uio_iov;
183		cnt = iov->iov_len;
184		if (cnt == 0) {
185			uio->uio_iov++;
186			uio->uio_iovcnt--;
187			continue;
188		}
189		if (cnt > n)
190			cnt = n;
191
192		switch (uio->uio_segflg) {
193
194		case UIO_USERSPACE:
195			maybe_yield();
196			if (uio->uio_rw == UIO_READ)
197				error = copyout(cp, iov->iov_base, cnt);
198			else
199				error = copyin(iov->iov_base, cp, cnt);
200			if (error)
201				goto out;
202			break;
203
204		case UIO_SYSSPACE:
205			if (uio->uio_rw == UIO_READ)
206				bcopy(cp, iov->iov_base, cnt);
207			else
208				bcopy(iov->iov_base, cp, cnt);
209			break;
210		case UIO_NOCOPY:
211			break;
212		}
213		iov->iov_base = (char *)iov->iov_base + cnt;
214		iov->iov_len -= cnt;
215		uio->uio_resid -= cnt;
216		uio->uio_offset += cnt;
217		cp = (char *)cp + cnt;
218		n -= cnt;
219	}
220out:
221	curthread_pflags_restore(save);
222	return (error);
223}
224
225/*
226 * Wrapper for uiomove() that validates the arguments against a known-good
227 * kernel buffer.  Currently, uiomove accepts a signed (n) argument, which
228 * is almost definitely a bad thing, so we catch that here as well.  We
229 * return a runtime failure, but it might be desirable to generate a runtime
230 * assertion failure instead.
231 */
232int
233uiomove_frombuf(void *buf, int buflen, struct uio *uio)
234{
235	size_t offset, n;
236
237	if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
238	    (offset = uio->uio_offset) != uio->uio_offset)
239		return (EINVAL);
240	if (buflen <= 0 || offset >= buflen)
241		return (0);
242	if ((n = buflen - offset) > IOSIZE_MAX)
243		return (EINVAL);
244	return (uiomove((char *)buf + offset, n, uio));
245}
246
247/*
248 * Give next character to user as result of read.
249 */
250int
251ureadc(int c, struct uio *uio)
252{
253	struct iovec *iov;
254	char *iov_base;
255
256	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
257	    "Calling ureadc()");
258
259again:
260	if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
261		panic("ureadc");
262	iov = uio->uio_iov;
263	if (iov->iov_len == 0) {
264		uio->uio_iovcnt--;
265		uio->uio_iov++;
266		goto again;
267	}
268	switch (uio->uio_segflg) {
269
270	case UIO_USERSPACE:
271		if (subyte(iov->iov_base, c) < 0)
272			return (EFAULT);
273		break;
274
275	case UIO_SYSSPACE:
276		iov_base = iov->iov_base;
277		*iov_base = c;
278		break;
279
280	case UIO_NOCOPY:
281		break;
282	}
283	iov->iov_base = (char *)iov->iov_base + 1;
284	iov->iov_len--;
285	uio->uio_resid--;
286	uio->uio_offset++;
287	return (0);
288}
289
290int
291copyinfrom(const void * __restrict src, void * __restrict dst, size_t len,
292    int seg)
293{
294	int error = 0;
295
296	switch (seg) {
297	case UIO_USERSPACE:
298		error = copyin(src, dst, len);
299		break;
300	case UIO_SYSSPACE:
301		bcopy(src, dst, len);
302		break;
303	default:
304		panic("copyinfrom: bad seg %d\n", seg);
305	}
306	return (error);
307}
308
309int
310copyinstrfrom(const void * __restrict src, void * __restrict dst, size_t len,
311    size_t * __restrict copied, int seg)
312{
313	int error = 0;
314
315	switch (seg) {
316	case UIO_USERSPACE:
317		error = copyinstr(src, dst, len, copied);
318		break;
319	case UIO_SYSSPACE:
320		error = copystr(src, dst, len, copied);
321		break;
322	default:
323		panic("copyinstrfrom: bad seg %d\n", seg);
324	}
325	return (error);
326}
327
328int
329copyiniov(const struct iovec *iovp, u_int iovcnt, struct iovec **iov, int error)
330{
331	u_int iovlen;
332
333	*iov = NULL;
334	if (iovcnt > UIO_MAXIOV)
335		return (error);
336	iovlen = iovcnt * sizeof (struct iovec);
337	*iov = malloc(iovlen, M_IOV, M_WAITOK);
338	error = copyin(iovp, *iov, iovlen);
339	if (error) {
340		free(*iov, M_IOV);
341		*iov = NULL;
342	}
343	return (error);
344}
345
346int
347copyinuio(const struct iovec *iovp, u_int iovcnt, struct uio **uiop)
348{
349	struct iovec *iov;
350	struct uio *uio;
351	u_int iovlen;
352	int error, i;
353
354	*uiop = NULL;
355	if (iovcnt > UIO_MAXIOV)
356		return (EINVAL);
357	iovlen = iovcnt * sizeof (struct iovec);
358	uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
359	iov = (struct iovec *)(uio + 1);
360	error = copyin(iovp, iov, iovlen);
361	if (error) {
362		free(uio, M_IOV);
363		return (error);
364	}
365	uio->uio_iov = iov;
366	uio->uio_iovcnt = iovcnt;
367	uio->uio_segflg = UIO_USERSPACE;
368	uio->uio_offset = -1;
369	uio->uio_resid = 0;
370	for (i = 0; i < iovcnt; i++) {
371		if (iov->iov_len > IOSIZE_MAX - uio->uio_resid) {
372			free(uio, M_IOV);
373			return (EINVAL);
374		}
375		uio->uio_resid += iov->iov_len;
376		iov++;
377	}
378	*uiop = uio;
379	return (0);
380}
381
382struct uio *
383cloneuio(struct uio *uiop)
384{
385	struct uio *uio;
386	int iovlen;
387
388	iovlen = uiop->uio_iovcnt * sizeof (struct iovec);
389	uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
390	*uio = *uiop;
391	uio->uio_iov = (struct iovec *)(uio + 1);
392	bcopy(uiop->uio_iov, uio->uio_iov, iovlen);
393	return (uio);
394}
395
396/*
397 * Map some anonymous memory in user space of size sz, rounded up to the page
398 * boundary.
399 */
400int
401copyout_map(struct thread *td, vm_offset_t *addr, size_t sz)
402{
403	struct vmspace *vms;
404	int error;
405	vm_size_t size;
406
407	vms = td->td_proc->p_vmspace;
408
409	/*
410	 * Map somewhere after heap in process memory.
411	 */
412	PROC_LOCK(td->td_proc);
413	*addr = round_page((vm_offset_t)vms->vm_daddr +
414	    lim_max(td->td_proc, RLIMIT_DATA));
415	PROC_UNLOCK(td->td_proc);
416
417	/* round size up to page boundry */
418	size = (vm_size_t)round_page(sz);
419
420	error = vm_mmap(&vms->vm_map, addr, size, PROT_READ | PROT_WRITE,
421	    VM_PROT_ALL, MAP_PRIVATE | MAP_ANON, OBJT_DEFAULT, NULL, 0);
422
423	return (error);
424}
425
426/*
427 * Unmap memory in user space.
428 */
429int
430copyout_unmap(struct thread *td, vm_offset_t addr, size_t sz)
431{
432	vm_map_t map;
433	vm_size_t size;
434
435	if (sz == 0)
436		return (0);
437
438	map = &td->td_proc->p_vmspace->vm_map;
439	size = (vm_size_t)round_page(sz);
440
441	if (vm_map_remove(map, addr, addr + size) != KERN_SUCCESS)
442		return (EINVAL);
443
444	return (0);
445}
446
447#ifdef NO_FUEWORD
448/*
449 * XXXKIB The temporal implementation of fue*() functions which do not
450 * handle usermode -1 properly, mixing it with the fault code.  Keep
451 * this until MD code is written.  Currently sparc64, mips and arm do
452 * not have proper implementation.
453 */
454
455int
456fueword(volatile const void *base, long *val)
457{
458	long res;
459
460	res = fuword(base);
461	if (res == -1)
462		return (-1);
463	*val = res;
464	return (0);
465}
466
467int
468fueword32(volatile const void *base, int32_t *val)
469{
470	int32_t res;
471
472	res = fuword32(base);
473	if (res == -1)
474		return (-1);
475	*val = res;
476	return (0);
477}
478
479#ifdef _LP64
480int
481fueword64(volatile const void *base, int64_t *val)
482{
483	int32_t res;
484
485	res = fuword64(base);
486	if (res == -1)
487		return (-1);
488	*val = res;
489	return (0);
490}
491#endif
492
493int
494casueword32(volatile uint32_t *base, uint32_t oldval, uint32_t *oldvalp,
495    uint32_t newval)
496{
497	int32_t ov;
498
499	ov = casuword32(base, oldval, newval);
500	if (ov == -1)
501		return (-1);
502	*oldvalp = ov;
503	return (0);
504}
505
506int
507casueword(volatile u_long *p, u_long oldval, u_long *oldvalp, u_long newval)
508{
509	u_long ov;
510
511	ov = casuword(p, oldval, newval);
512	if (ov == -1)
513		return (-1);
514	*oldvalp = ov;
515	return (0);
516}
517#else /* NO_FUEWORD */
518int32_t
519fuword32(volatile const void *addr)
520{
521	int rv;
522	int32_t val;
523
524	rv = fueword32(addr, &val);
525	return (rv == -1 ? -1 : val);
526}
527
528#ifdef _LP64
529int64_t
530fuword64(volatile const void *addr)
531{
532	int rv;
533	int64_t val;
534
535	rv = fueword64(addr, &val);
536	return (rv == -1 ? -1 : val);
537}
538#endif /* _LP64 */
539
540long
541fuword(volatile const void *addr)
542{
543	long val;
544	int rv;
545
546	rv = fueword(addr, &val);
547	return (rv == -1 ? -1 : val);
548}
549
550uint32_t
551casuword32(volatile uint32_t *addr, uint32_t old, uint32_t new)
552{
553	int rv;
554	uint32_t val;
555
556	rv = casueword32(addr, old, &val, new);
557	return (rv == -1 ? -1 : val);
558}
559
560u_long
561casuword(volatile u_long *addr, u_long old, u_long new)
562{
563	int rv;
564	u_long val;
565
566	rv = casueword(addr, old, &val, new);
567	return (rv == -1 ? -1 : val);
568}
569
570#endif /* NO_FUEWORD */
571