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 } 431 432