| 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 | * 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 |
| 75 | * lengths. |
| 76 | */ |
| 77 | int |
| 78 | uiomove(caddr_t cp, size_t n, struct uio *uio) |
| 79 | { |
| 80 | struct iovec *iov; |
| 81 | size_t cnt; |
| 82 | int error = 0; |
| 83 | int save = 0; |
| 84 | int baseticks = ticks; |
| 85 | |
| 86 | KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE, |
| 87 | ("uiomove: mode")); |
| 88 | KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread, |
| 89 | ("uiomove proc")); |
| 90 | |
| 91 | if (curproc) { |
| 92 | save = curproc->p_flag & P_DEADLKTREAT; |
| 93 | curproc->p_flag |= P_DEADLKTREAT; |
| 94 | } |
| 95 | |
| 96 | while (n > 0 && uio->uio_resid) { |
| 97 | iov = uio->uio_iov; |
| 98 | cnt = iov->iov_len; |
| 99 | if (cnt == 0) { |
| 100 | uio->uio_iov++; |
| 101 | uio->uio_iovcnt--; |
| 102 | continue; |
| 103 | } |
| 104 | if (cnt > n) |
| 105 | cnt = n; |
| 106 | |
| 107 | switch (uio->uio_segflg) { |
| 108 | |
| 109 | case UIO_USERSPACE: |
| 110 | if (ticks - baseticks >= hogticks) { |
| 111 | uio_yield(); |
| 112 | baseticks = ticks; |
| 113 | } |
| 114 | if (uio->uio_rw == UIO_READ) |
| 115 | error = copyout(cp, iov->iov_base, cnt); |
| 116 | else |
| 117 | error = copyin(iov->iov_base, cp, cnt); |
| 118 | if (error) |
| 119 | break; |
| 120 | break; |
| 121 | |
| 122 | case UIO_SYSSPACE: |
| 123 | if (uio->uio_rw == UIO_READ) |
| 124 | bcopy((caddr_t)cp, iov->iov_base, cnt); |
| 125 | else |
| 126 | bcopy(iov->iov_base, (caddr_t)cp, cnt); |
| 127 | break; |
| 128 | case UIO_NOCOPY: |
| 129 | break; |
| 130 | } |
| 131 | iov->iov_base = (char *)iov->iov_base + cnt; |
| 132 | iov->iov_len -= cnt; |
| 133 | uio->uio_resid -= cnt; |
| 134 | uio->uio_offset += cnt; |
| 135 | cp += cnt; |
| 136 | n -= cnt; |
| 137 | } |
| 138 | if (curproc) |
| 139 | curproc->p_flag = (curproc->p_flag & ~P_DEADLKTREAT) | save; |
| 140 | return (error); |
| 141 | } |
| 142 | /* |
| 143 | * Wrapper for uiomove() that validates the arguments against a known-good |
| 144 | * kernel buffer. |
| 145 | */ |
| 146 | int |
| 147 | uiomove_frombuf(void *buf, size_t buflen, struct uio *uio) |
| 148 | { |
| 149 | size_t offset; |
| 150 | |
| 151 | offset = (size_t)uio->uio_offset; |
| 152 | if ((off_t)offset != uio->uio_offset) |
| 153 | return (EINVAL); |
| 154 | if (buflen == 0 || offset >= buflen) |
| 155 | return (0); |
| 156 | return (uiomove((char *)buf + offset, buflen - offset, uio)); |
| 157 | } |
| 158 | |
| 159 | /* |
| 160 | * Give next character to user as result of read. |
| 161 | */ |
| 162 | int |
| 163 | ureadc(int c, struct uio *uio) |
| 164 | { |
| 165 | struct iovec *iov; |
| 166 | char *iov_base; |
| 167 | |
| 168 | again: |
| 169 | if (uio->uio_iovcnt == 0 || uio->uio_resid == 0) |
| 170 | panic("ureadc"); |
| 171 | iov = uio->uio_iov; |
| 172 | if (iov->iov_len == 0) { |
| 173 | uio->uio_iovcnt--; |
| 174 | uio->uio_iov++; |
| 175 | goto again; |
| 176 | } |
| 177 | switch (uio->uio_segflg) { |
| 178 | |
| 179 | case UIO_USERSPACE: |
| 180 | if (subyte(iov->iov_base, c) < 0) |
| 181 | return (EFAULT); |
| 182 | break; |
| 183 | |
| 184 | case UIO_SYSSPACE: |
| 185 | iov_base = iov->iov_base; |
| 186 | *iov_base = c; |
| 187 | iov->iov_base = iov_base; |
| 188 | break; |
| 189 | |
| 190 | case UIO_NOCOPY: |
| 191 | break; |
| 192 | } |
| 193 | iov->iov_base = (char *)iov->iov_base + 1; |
| 194 | iov->iov_len--; |
| 195 | uio->uio_resid--; |
| 196 | uio->uio_offset++; |
| 197 | return (0); |
| 198 | } |
| 199 | |
| 200 | /* |
| 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. |
| 204 | */ |
| 205 | void * |
| 206 | hashinit(int elements, struct malloc_type *type, u_long *hashmask) |
| 207 | { |
| 208 | long hashsize; |
| 209 | LIST_HEAD(generic, generic) *hashtbl; |
| 210 | int i; |
| 211 | |
| 212 | if (elements <= 0) |
| 213 | panic("hashinit: bad elements"); |
| 214 | for (hashsize = 2; hashsize < elements; hashsize <<= 1) |
| 215 | continue; |
| 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; |
| 220 | return (hashtbl); |
| 221 | } |
| 222 | |
| 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])) |
| 227 | |
| 228 | /* |
| 229 | * General routine to allocate a prime number sized hash table. |
| 230 | */ |
| 231 | void * |
| 232 | phashinit(int elements, struct malloc_type *type, u_long *nentries) |
| 233 | { |
| 234 | long hashsize; |
| 235 | LIST_HEAD(generic, generic) *hashtbl; |
| 236 | int i; |
| 237 | |
| 238 | if (elements <= 0) |
| 239 | panic("phashinit: bad elements"); |
| 240 | for (i = 1, hashsize = primes[1]; hashsize <= elements;) { |
| 241 | i++; |
| 242 | if (i == NPRIMES) |
| 243 | break; |
| 244 | hashsize = primes[i]; |
| 245 | } |
| 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; |
| 251 | return (hashtbl); |
| 252 | } |
| 253 | |
| 254 | /* |
| 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. |
| 258 | * |
| 259 | * MPSAFE |
| 260 | */ |
| 261 | int |
| 262 | iovec_copyin(struct iovec *uiov, struct iovec **kiov, struct iovec *siov, |
| 263 | size_t iov_cnt, size_t *iov_len) |
| 264 | { |
| 265 | struct iovec *iovp; |
| 266 | int error, i; |
| 267 | size_t len; |
| 268 | |
| 269 | if (iov_cnt > UIO_MAXIOV) |
| 270 | return EMSGSIZE; |
| 271 | if (iov_cnt > UIO_SMALLIOV) { |
| 272 | MALLOC(*kiov, struct iovec *, sizeof(struct iovec) * iov_cnt, |
| 273 | M_IOV, M_WAITOK); |
| 274 | } else { |
| 275 | *kiov = siov; |
| 276 | } |
| 277 | error = copyin(uiov, *kiov, iov_cnt * sizeof(struct iovec)); |
| 278 | if (error == 0) { |
| 279 | *iov_len = 0; |
| 280 | for (i = 0, iovp = *kiov; i < iov_cnt; i++, iovp++) { |
| 281 | /* |
| 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. |
| 285 | * |
| 286 | * GCC4 - overflow check opt requires assign/test. |
| 287 | */ |
| 288 | len = *iov_len + iovp->iov_len; |
| 289 | if (len < *iov_len) |
| 290 | error = EINVAL; |
| 291 | *iov_len = len; |
| 292 | } |
| 293 | } |
| 294 | |
| 295 | /* |
| 296 | * From userland disallow iovec's which exceed the sized size |
| 297 | * limit as the system calls return ssize_t. |
| 298 | * |
| 299 | * NOTE: Internal kernel interfaces can handle the unsigned |
| 300 | * limit. |
| 301 | */ |
| 302 | if (error == 0 && (ssize_t)*iov_len < 0) |
| 303 | error = EINVAL; |
| 304 | |
| 305 | if (error) |
| 306 | iovec_free(kiov, siov); |
| 307 | return (error); |
| 308 | } |
| 309 | |
| 310 | |
| 311 | /* |
| 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. |
| 320 | * |
| 321 | * Redistribution and use in source and binary forms, with or without |
| 322 | * modification, are permitted provided that the following conditions |
| 323 | * are met: |
| 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. |
| 332 | * |
| 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 |
| 343 | * SUCH DAMAGE. |
| 344 | * |
| 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 $ |
| 347 | */ |
| 348 | |
| 349 | /* |
| 350 | * Implement uiomove(9) from physical memory using sf_bufs to reduce |
| 351 | * the creation and destruction of ephemeral mappings. |
| 352 | */ |
| 353 | int |
| 354 | uiomove_fromphys(vm_page_t *ma, vm_offset_t offset, size_t n, struct uio *uio) |
| 355 | { |
| 356 | struct sf_buf *sf; |
| 357 | struct thread *td = curthread; |
| 358 | struct iovec *iov; |
| 359 | void *cp; |
| 360 | vm_offset_t page_offset; |
| 361 | vm_page_t m; |
| 362 | size_t cnt; |
| 363 | int error = 0; |
| 364 | int save = 0; |
| 365 | |
| 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")); |
| 370 | |
| 371 | crit_enter(); |
| 372 | save = td->td_flags & TDF_DEADLKTREAT; |
| 373 | td->td_flags |= TDF_DEADLKTREAT; |
| 374 | crit_exit(); |
| 375 | |
| 376 | while (n > 0 && uio->uio_resid) { |
| 377 | iov = uio->uio_iov; |
| 378 | cnt = iov->iov_len; |
| 379 | if (cnt == 0) { |
| 380 | uio->uio_iov++; |
| 381 | uio->uio_iovcnt--; |
| 382 | continue; |
| 383 | } |
| 384 | if (cnt > n) |
| 385 | cnt = n; |
| 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) { |
| 392 | case UIO_USERSPACE: |
| 393 | /* |
| 394 | * note: removed uioyield (it was the wrong place to |
| 395 | * put it). |
| 396 | */ |
| 397 | if (uio->uio_rw == UIO_READ) |
| 398 | error = copyout(cp, iov->iov_base, cnt); |
| 399 | else |
| 400 | error = copyin(iov->iov_base, cp, cnt); |
| 401 | if (error) { |
| 402 | sf_buf_free(sf); |
| 403 | goto out; |
| 404 | } |
| 405 | break; |
| 406 | case UIO_SYSSPACE: |
| 407 | if (uio->uio_rw == UIO_READ) |
| 408 | bcopy(cp, iov->iov_base, cnt); |
| 409 | else |
| 410 | bcopy(iov->iov_base, cp, cnt); |
| 411 | break; |
| 412 | case UIO_NOCOPY: |
| 413 | break; |
| 414 | } |
| 415 | sf_buf_free(sf); |
| 416 | iov->iov_base = (char *)iov->iov_base + cnt; |
| 417 | iov->iov_len -= cnt; |
| 418 | uio->uio_resid -= cnt; |
| 419 | uio->uio_offset += cnt; |
| 420 | offset += cnt; |
| 421 | n -= cnt; |
| 422 | } |
| 423 | out: |
| 424 | if (save == 0) { |
| 425 | crit_enter(); |
| 426 | td->td_flags &= ~TDF_DEADLKTREAT; |
| 427 | crit_exit(); |
| 428 | } |
| 429 | return (error); |
| 430 | } |
| 431 | |