sys/kern/kern_subr.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  * 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.
  25  *
  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
  36  * SUCH DAMAGE.
  37  *
  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 $
  41  */
  42
  43 #include "opt_ddb.h"
  44
  45 #include <sys/param.h>
  46 #include <sys/systm.h>
  47 #include <sys/kernel.h>
  48 #include <sys/proc.h>
  49 #include <sys/malloc.h>
  50 #include <sys/lock.h>
  51 #include <sys/resourcevar.h>
  52 #include <sys/sysctl.h>
  53 #include <sys/uio.h>
  54 #include <sys/vnode.h>
  55 #include <sys/sfbuf.h>
  56 #include <sys/thread2.h>
  57 #include <machine/limits.h>
  58
  59 #include <vm/vm.h>
  60 #include <vm/vm_page.h>
  61 #include <vm/vm_map.h>
  62
  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)");
  65
  66 /*
  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
  69  *
  70  * For userspace UIO's, uio_td must be the current thread.
  71  */
  72 int
  73 uiomove(caddr_t cp, int n, struct uio *uio)
  74 {
  75         struct iovec *iov;
  76         u_int cnt;
  77         int error = 0;
  78         int save = 0;
  79         int baseticks = ticks;
  80
  81         KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
  82             ("uiomove: mode"));
  83         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
  84             ("uiomove proc"));
  85
  86         if (curproc) {
  87                 save = curproc->p_flag & P_DEADLKTREAT;
  88                 curproc->p_flag |= P_DEADLKTREAT;
  89         }
  90
  91         while (n > 0 && uio->uio_resid) {
  92                 iov = uio->uio_iov;
  93                 cnt = iov->iov_len;
  94                 if (cnt == 0) {
  95                         uio->uio_iov++;
  96                         uio->uio_iovcnt--;
  97                         continue;
  98                 }
  99                 if (cnt > n)
 100                         cnt = n;
 101
 102                 switch (uio->uio_segflg) {
 103
 104                 case UIO_USERSPACE:
 105                         if (ticks - baseticks >= hogticks) {
 106                                 uio_yield();
 107                                 baseticks = ticks;
 108                         }
 109                         if (uio->uio_rw == UIO_READ)
 110                                 error = copyout(cp, iov->iov_base, cnt);
 111                         else
 112                                 error = copyin(iov->iov_base, cp, cnt);
 113                         if (error)
 114                                 break;
 115                         break;
 116
 117                 case UIO_SYSSPACE:
 118                         if (uio->uio_rw == UIO_READ)
 119                                 bcopy((caddr_t)cp, iov->iov_base, cnt);
 120                         else
 121                                 bcopy(iov->iov_base, (caddr_t)cp, cnt);
 122                         break;
 123                 case UIO_NOCOPY:
 124                         break;
 125                 }
 126                 iov->iov_base = (char *)iov->iov_base + cnt;
 127                 iov->iov_len -= cnt;
 128                 uio->uio_resid -= cnt;
 129                 uio->uio_offset += cnt;
 130                 cp += cnt;
 131                 n -= cnt;
 132         }
 133         if (curproc)
 134                 curproc->p_flag = (curproc->p_flag & ~P_DEADLKTREAT) | save;
 135         return (error);
 136 }
 137 /*
 138  * Wrapper for uiomove() that validates the arguments against a known-good
 139  * kernel buffer.  Currently, uiomove accepts a signed (n) argument, which
 140  * is almost definitely a bad thing, so we catch that here as well.  We
 141  * return a runtime failure, but it might be desirable to generate a runtime
 142  * assertion failure instead.
 143  */
 144 int
 145 uiomove_frombuf(void *buf, int buflen, struct uio *uio)
 146 {
 147         unsigned int offset, n;
 148
 149         if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
 150             (offset = uio->uio_offset) != uio->uio_offset)
 151                 return (EINVAL);
 152         if (buflen <= 0 || offset >= buflen)
 153                 return (0);
 154         if ((n = buflen - offset) > INT_MAX)
 155                 return (EINVAL);
 156         return (uiomove((char *)buf + offset, n, uio));
 157 }
 158
 159
 160 int
 161 uiomoveco(caddr_t cp, int n, struct uio *uio, struct vm_object *obj)
 162 {
 163         struct iovec *iov;
 164         u_int cnt;
 165         int error;
 166         int baseticks = ticks;
 167
 168         KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
 169             ("uiomoveco: mode"));
 170         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
 171             ("uiomoveco proc"));
 172
 173         while (n > 0 && uio->uio_resid) {
 174                 iov = uio->uio_iov;
 175                 cnt = iov->iov_len;
 176                 if (cnt == 0) {
 177                         uio->uio_iov++;
 178                         uio->uio_iovcnt--;
 179                         continue;
 180                 }
 181                 if (cnt > n)
 182                         cnt = n;
 183
 184                 switch (uio->uio_segflg) {
 185
 186                 case UIO_USERSPACE:
 187                         if (ticks - baseticks >= hogticks) {
 188                                 uio_yield();
 189                                 baseticks = ticks;
 190                         }
 191                         if (uio->uio_rw == UIO_READ) {
 192                                 error = copyout(cp, iov->iov_base, cnt);
 193                         } else {
 194                                 error = copyin(iov->iov_base, cp, cnt);
 195                         }
 196                         if (error)
 197                                 return (error);
 198                         break;
 199
 200                 case UIO_SYSSPACE:
 201                         if (uio->uio_rw == UIO_READ)
 202                                 bcopy((caddr_t)cp, iov->iov_base, cnt);
 203                         else
 204                                 bcopy(iov->iov_base, (caddr_t)cp, cnt);
 205                         break;
 206                 case UIO_NOCOPY:
 207                         break;
 208                 }
 209                 iov->iov_base = (char *)iov->iov_base + cnt;
 210                 iov->iov_len -= cnt;
 211                 uio->uio_resid -= cnt;
 212                 uio->uio_offset += cnt;
 213                 cp += cnt;
 214                 n -= cnt;
 215         }
 216         return (0);
 217 }
 218
 219 /*
 220  * Give next character to user as result of read.
 221  */
 222 int
 223 ureadc(int c, struct uio *uio)
 224 {
 225         struct iovec *iov;
 226         char *iov_base;
 227
 228 again:
 229         if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
 230                 panic("ureadc");
 231         iov = uio->uio_iov;
 232         if (iov->iov_len == 0) {
 233                 uio->uio_iovcnt--;
 234                 uio->uio_iov++;
 235                 goto again;
 236         }
 237         switch (uio->uio_segflg) {
 238
 239         case UIO_USERSPACE:
 240                 if (subyte(iov->iov_base, c) < 0)
 241                         return (EFAULT);
 242                 break;
 243
 244         case UIO_SYSSPACE:
 245                 iov_base = iov->iov_base;
 246                 *iov_base = c;
 247                 iov->iov_base = iov_base;
 248                 break;
 249
 250         case UIO_NOCOPY:
 251                 break;
 252         }
 253         iov->iov_base = (char *)iov->iov_base + 1;
 254         iov->iov_len--;
 255         uio->uio_resid--;
 256         uio->uio_offset++;
 257         return (0);
 258 }
 259
 260 /*
 261  * General routine to allocate a hash table.  Make the hash table size a
 262  * power of 2 greater or equal to the number of elements requested, and
 263  * store the masking value in *hashmask.
 264  */
 265 void *
 266 hashinit(int elements, struct malloc_type *type, u_long *hashmask)
 267 {
 268         long hashsize;
 269         LIST_HEAD(generic, generic) *hashtbl;
 270         int i;
 271
 272         if (elements <= 0)
 273                 panic("hashinit: bad elements");
 274         for (hashsize = 2; hashsize < elements; hashsize <<= 1)
 275                 continue;
 276         hashtbl = kmalloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
 277         for (i = 0; i < hashsize; i++)
 278                 LIST_INIT(&hashtbl[i]);
 279         *hashmask = hashsize - 1;
 280         return (hashtbl);
 281 }
 282
 283 static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039,
 284                         2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653,
 285                         7159, 7673, 8191, 12281, 16381, 24571, 32749 };
 286 #define NPRIMES (sizeof(primes) / sizeof(primes[0]))
 287
 288 /*
 289  * General routine to allocate a prime number sized hash table.
 290  */
 291 void *
 292 phashinit(int elements, struct malloc_type *type, u_long *nentries)
 293 {
 294         long hashsize;
 295         LIST_HEAD(generic, generic) *hashtbl;
 296         int i;
 297
 298         if (elements <= 0)
 299                 panic("phashinit: bad elements");
 300         for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
 301                 i++;
 302                 if (i == NPRIMES)
 303                         break;
 304                 hashsize = primes[i];
 305         }
 306         hashsize = primes[i - 1];
 307         hashtbl = kmalloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
 308         for (i = 0; i < hashsize; i++)
 309                 LIST_INIT(&hashtbl[i]);
 310         *nentries = hashsize;
 311         return (hashtbl);
 312 }
 313
 314 /*
 315  * Copyin an iovec.  If the iovec array fits, use the preallocated small
 316  * iovec structure.  If it is too big, dynamically allocate an iovec array
 317  * of sufficient size.
 318  *
 319  * MPSAFE
 320  */
 321 int
 322 iovec_copyin(struct iovec *uiov, struct iovec **kiov, struct iovec *siov,
 323              size_t iov_cnt, int *iov_len)
 324 {
 325         struct iovec *iovp;
 326         int error, i;
 327
 328         if (iov_cnt > UIO_MAXIOV)
 329                 return EMSGSIZE;
 330         if (iov_cnt > UIO_SMALLIOV) {
 331                 MALLOC(*kiov, struct iovec *, sizeof(struct iovec) * iov_cnt,
 332                     M_IOV, M_WAITOK);
 333         } else {
 334                 *kiov = siov;
 335         }
 336         error = copyin(uiov, *kiov, iov_cnt * sizeof(struct iovec));
 337         if (error == 0) {
 338                 *iov_len = 0;
 339                 for (i = 0, iovp = *kiov; i < iov_cnt; i++, iovp++) {
 340                         /*
 341                          * Check for both *iov_len overflows and out of
 342                          * range iovp->iov_len's.  We limit to the
 343                          * capabilities of signed integers.
 344                          */
 345                         if (*iov_len + (int)iovp->iov_len < *iov_len)
 346                                 error = EINVAL;
 347                         *iov_len += (int)iovp->iov_len;
 348                 }
 349         }
 350         if (error)
 351                 iovec_free(kiov, siov);
 352         return (error);
 353 }
 354
 355
 356 /*
 357  * Copyright (c) 2004 Alan L. Cox <alc@cs.rice.edu>
 358  * Copyright (c) 1982, 1986, 1991, 1993
 359  *      The Regents of the University of California.  All rights reserved.
 360  * (c) UNIX System Laboratories, Inc.
 361  * All or some portions of this file are derived from material licensed
 362  * to the University of California by American Telephone and Telegraph
 363  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 364  * the permission of UNIX System Laboratories, Inc.
 365  *
 366  * Redistribution and use in source and binary forms, with or without
 367  * modification, are permitted provided that the following conditions
 368  * are met:
 369  * 1. Redistributions of source code must retain the above copyright
 370  *    notice, this list of conditions and the following disclaimer.
 371  * 2. Redistributions in binary form must reproduce the above copyright
 372  *    notice, this list of conditions and the following disclaimer in the
 373  *    documentation and/or other materials provided with the distribution.
 374  * 4. Neither the name of the University nor the names of its contributors
 375  *    may be used to endorse or promote products derived from this software
 376  *    without specific prior written permission.
 377  *
 378  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 379  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 380  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 381  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 382  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 383  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 384  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 385  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 386  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 387  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 388  * SUCH DAMAGE.
 389  *
 390  * @(#)kern_subr.c      8.3 (Berkeley) 1/21/94
 391  * $FreeBSD: src/sys/i386/i386/uio_machdep.c,v 1.1 2004/03/21 20:28:36 alc Exp $
 392  */
 393
 394 /*
 395  * Implement uiomove(9) from physical memory using sf_bufs to reduce
 396  * the creation and destruction of ephemeral mappings.
 397  */
 398 int
 399 uiomove_fromphys(vm_page_t *ma, vm_offset_t offset, int n, struct uio *uio)
 400 {
 401         struct sf_buf *sf;
 402         struct thread *td = curthread;
 403         struct iovec *iov;
 404         void *cp;
 405         vm_offset_t page_offset;
 406         vm_page_t m;
 407         size_t cnt;
 408         int error = 0;
 409         int save = 0;
 410
 411         KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
 412             ("uiomove_fromphys: mode"));
 413         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
 414             ("uiomove_fromphys proc"));
 415
 416         crit_enter();
 417         save = td->td_flags & TDF_DEADLKTREAT;
 418         td->td_flags |= TDF_DEADLKTREAT;
 419         crit_exit();
 420
 421         while (n > 0 && uio->uio_resid) {
 422                 iov = uio->uio_iov;
 423                 cnt = iov->iov_len;
 424                 if (cnt == 0) {
 425                         uio->uio_iov++;
 426                         uio->uio_iovcnt--;
 427                         continue;
 428                 }
 429                 if (cnt > n)
 430                         cnt = n;
 431                 page_offset = offset & PAGE_MASK;
 432                 cnt = min(cnt, PAGE_SIZE - page_offset);
 433                 m = ma[offset >> PAGE_SHIFT];
 434                 sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
 435                 cp = (char *)sf_buf_kva(sf) + page_offset;
 436                 switch (uio->uio_segflg) {
 437                 case UIO_USERSPACE:
 438                         /*
 439                          * note: removed uioyield (it was the wrong place to
 440                          * put it).
 441                          */
 442                         if (uio->uio_rw == UIO_READ)
 443                                 error = copyout(cp, iov->iov_base, cnt);
 444                         else
 445                                 error = copyin(iov->iov_base, cp, cnt);
 446                         if (error) {
 447                                 sf_buf_free(sf);
 448                                 goto out;
 449                         }
 450                         break;
 451                 case UIO_SYSSPACE:
 452                         if (uio->uio_rw == UIO_READ)
 453                                 bcopy(cp, iov->iov_base, cnt);
 454                         else
 455                                 bcopy(iov->iov_base, cp, cnt);
 456                         break;
 457                 case UIO_NOCOPY:
 458                         break;
 459                 }
 460                 sf_buf_free(sf);
 461                 iov->iov_base = (char *)iov->iov_base + cnt;
 462                 iov->iov_len -= cnt;
 463                 uio->uio_resid -= cnt;
 464                 uio->uio_offset += cnt;
 465                 offset += cnt;
 466                 n -= cnt;
 467         }
 468 out:
 469         if (save == 0) {
 470                 crit_enter();
 471                 td->td_flags &= ~TDF_DEADLKTREAT;
 472                 crit_exit();
 473         }
 474         return (error);
 475 }
 476