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.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
39 * $FreeBSD: src/sys/kern/kern_subr.c,v 1.31.2.2 2002/04/21 08:09:37 bde Exp $
40 * $DragonFly: src/sys/kern/kern_subr.c,v 1.27 2007/01/29 20:44:02 tgen Exp $
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
49 #include <sys/malloc.h>
51 #include <sys/resourcevar.h>
52 #include <sys/sysctl.h>
54 #include <sys/vnode.h>
55 #include <sys/sfbuf.h>
56 #include <sys/thread2.h>
57 #include <machine/limits.h>
60 #include <vm/vm_page.h>
61 #include <vm/vm_map.h>
63 SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, NULL, UIO_MAXIOV,
64 "Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
67 * UIO_READ: copy the kernelspace cp to the user or kernelspace UIO
68 * UIO_WRITE: copy the user or kernelspace UIO to the kernelspace cp
70 * For userspace UIO's, uio_td must be the current thread.
72 * The syscall interface is responsible for limiting the length to
73 * ssize_t for things like read() or write() which return the bytes
74 * read or written as ssize_t. These functions work with unsigned
78 uiomove(caddr_t cp, size_t n, struct uio *uio)
84 int baseticks = ticks;
86 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
88 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
92 save = curproc->p_flag & P_DEADLKTREAT;
93 curproc->p_flag |= P_DEADLKTREAT;
96 while (n > 0 && uio->uio_resid) {
107 switch (uio->uio_segflg) {
110 if (ticks - baseticks >= hogticks) {
114 if (uio->uio_rw == UIO_READ)
115 error = copyout(cp, iov->iov_base, cnt);
117 error = copyin(iov->iov_base, cp, cnt);
123 if (uio->uio_rw == UIO_READ)
124 bcopy((caddr_t)cp, iov->iov_base, cnt);
126 bcopy(iov->iov_base, (caddr_t)cp, cnt);
131 iov->iov_base = (char *)iov->iov_base + cnt;
133 uio->uio_resid -= cnt;
134 uio->uio_offset += cnt;
139 curproc->p_flag = (curproc->p_flag & ~P_DEADLKTREAT) | save;
143 * Wrapper for uiomove() that validates the arguments against a known-good
147 uiomove_frombuf(void *buf, size_t buflen, struct uio *uio)
151 offset = (size_t)uio->uio_offset;
152 if ((off_t)offset != uio->uio_offset)
154 if (buflen == 0 || offset >= buflen)
156 return (uiomove((char *)buf + offset, buflen - offset, uio));
160 * Give next character to user as result of read.
163 ureadc(int c, struct uio *uio)
169 if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
172 if (iov->iov_len == 0) {
177 switch (uio->uio_segflg) {
180 if (subyte(iov->iov_base, c) < 0)
185 iov_base = iov->iov_base;
187 iov->iov_base = iov_base;
193 iov->iov_base = (char *)iov->iov_base + 1;
201 * General routine to allocate a hash table. Make the hash table size a
202 * power of 2 greater or equal to the number of elements requested, and
203 * store the masking value in *hashmask.
206 hashinit(int elements, struct malloc_type *type, u_long *hashmask)
209 LIST_HEAD(generic, generic) *hashtbl;
213 panic("hashinit: bad elements");
214 for (hashsize = 2; hashsize < elements; hashsize <<= 1)
216 hashtbl = kmalloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
217 for (i = 0; i < hashsize; i++)
218 LIST_INIT(&hashtbl[i]);
219 *hashmask = hashsize - 1;
223 static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039,
224 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653,
225 7159, 7673, 8191, 12281, 16381, 24571, 32749 };
226 #define NPRIMES (sizeof(primes) / sizeof(primes[0]))
229 * General routine to allocate a prime number sized hash table.
232 phashinit(int elements, struct malloc_type *type, u_long *nentries)
235 LIST_HEAD(generic, generic) *hashtbl;
239 panic("phashinit: bad elements");
240 for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
244 hashsize = primes[i];
246 hashsize = primes[i - 1];
247 hashtbl = kmalloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
248 for (i = 0; i < hashsize; i++)
249 LIST_INIT(&hashtbl[i]);
250 *nentries = hashsize;
255 * Copyin an iovec. If the iovec array fits, use the preallocated small
256 * iovec structure. If it is too big, dynamically allocate an iovec array
257 * of sufficient size.
262 iovec_copyin(struct iovec *uiov, struct iovec **kiov, struct iovec *siov,
263 size_t iov_cnt, size_t *iov_len)
269 if (iov_cnt > UIO_MAXIOV)
271 if (iov_cnt > UIO_SMALLIOV) {
272 MALLOC(*kiov, struct iovec *, sizeof(struct iovec) * iov_cnt,
277 error = copyin(uiov, *kiov, iov_cnt * sizeof(struct iovec));
280 for (i = 0, iovp = *kiov; i < iov_cnt; i++, iovp++) {
282 * Check for both *iov_len overflows and out of
283 * range iovp->iov_len's. We limit to the
284 * capabilities of signed integers.
286 * GCC4 - overflow check opt requires assign/test.
288 len = *iov_len + iovp->iov_len;
296 * From userland disallow iovec's which exceed the sized size
297 * limit as the system calls return ssize_t.
299 * NOTE: Internal kernel interfaces can handle the unsigned
302 if (error == 0 && (ssize_t)*iov_len < 0)
306 iovec_free(kiov, siov);
312 * Copyright (c) 2004 Alan L. Cox <alc@cs.rice.edu>
313 * Copyright (c) 1982, 1986, 1991, 1993
314 * The Regents of the University of California. All rights reserved.
315 * (c) UNIX System Laboratories, Inc.
316 * All or some portions of this file are derived from material licensed
317 * to the University of California by American Telephone and Telegraph
318 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
319 * the permission of UNIX System Laboratories, Inc.
321 * Redistribution and use in source and binary forms, with or without
322 * modification, are permitted provided that the following conditions
324 * 1. Redistributions of source code must retain the above copyright
325 * notice, this list of conditions and the following disclaimer.
326 * 2. Redistributions in binary form must reproduce the above copyright
327 * notice, this list of conditions and the following disclaimer in the
328 * documentation and/or other materials provided with the distribution.
329 * 4. Neither the name of the University nor the names of its contributors
330 * may be used to endorse or promote products derived from this software
331 * without specific prior written permission.
333 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
334 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
335 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
336 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
337 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
338 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
339 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
340 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
341 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
342 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
345 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
346 * $FreeBSD: src/sys/i386/i386/uio_machdep.c,v 1.1 2004/03/21 20:28:36 alc Exp $
350 * Implement uiomove(9) from physical memory using sf_bufs to reduce
351 * the creation and destruction of ephemeral mappings.
354 uiomove_fromphys(vm_page_t *ma, vm_offset_t offset, size_t n, struct uio *uio)
357 struct thread *td = curthread;
360 vm_offset_t page_offset;
366 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
367 ("uiomove_fromphys: mode"));
368 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
369 ("uiomove_fromphys proc"));
372 save = td->td_flags & TDF_DEADLKTREAT;
373 td->td_flags |= TDF_DEADLKTREAT;
376 while (n > 0 && uio->uio_resid) {
386 page_offset = offset & PAGE_MASK;
387 cnt = min(cnt, PAGE_SIZE - page_offset);
388 m = ma[offset >> PAGE_SHIFT];
389 sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
390 cp = (char *)sf_buf_kva(sf) + page_offset;
391 switch (uio->uio_segflg) {
394 * note: removed uioyield (it was the wrong place to
397 if (uio->uio_rw == UIO_READ)
398 error = copyout(cp, iov->iov_base, cnt);
400 error = copyin(iov->iov_base, cp, cnt);
407 if (uio->uio_rw == UIO_READ)
408 bcopy(cp, iov->iov_base, cnt);
410 bcopy(iov->iov_base, cp, cnt);
416 iov->iov_base = (char *)iov->iov_base + cnt;
418 uio->uio_resid -= cnt;
419 uio->uio_offset += cnt;
426 td->td_flags &= ~TDF_DEADLKTREAT;