Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/sys_generic.c
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1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)sys_generic.c 8.5 (Berkeley) 1/21/94 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include "opt_capsicum.h" 43 #include "opt_ktrace.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/sysproto.h> 48 #include <sys/capsicum.h> 49 #include <sys/filedesc.h> 50 #include <sys/filio.h> 51 #include <sys/fcntl.h> 52 #include <sys/file.h> 53 #include <sys/lock.h> 54 #include <sys/proc.h> 55 #include <sys/signalvar.h> 56 #include <sys/socketvar.h> 57 #include <sys/uio.h> 58 #include <sys/eventfd.h> 59 #include <sys/kernel.h> 60 #include <sys/ktr.h> 61 #include <sys/limits.h> 62 #include <sys/malloc.h> 63 #include <sys/poll.h> 64 #include <sys/resourcevar.h> 65 #include <sys/selinfo.h> 66 #include <sys/sleepqueue.h> 67 #include <sys/specialfd.h> 68 #include <sys/syscallsubr.h> 69 #include <sys/sysctl.h> 70 #include <sys/sysent.h> 71 #include <sys/vnode.h> 72 #include <sys/bio.h> 73 #include <sys/buf.h> 74 #include <sys/condvar.h> 75 #ifdef KTRACE 76 #include <sys/ktrace.h> 77 #endif 78 79 #include <security/audit/audit.h> 80 81 /* 82 * The following macro defines how many bytes will be allocated from 83 * the stack instead of memory allocated when passing the IOCTL data 84 * structures from userspace and to the kernel. Some IOCTLs having 85 * small data structures are used very frequently and this small 86 * buffer on the stack gives a significant speedup improvement for 87 * those requests. The value of this define should be greater or equal 88 * to 64 bytes and should also be power of two. The data structure is 89 * currently hard-aligned to a 8-byte boundary on the stack. This 90 * should currently be sufficient for all supported platforms. 91 */ 92 #define SYS_IOCTL_SMALL_SIZE 128 /* bytes */ 93 #define SYS_IOCTL_SMALL_ALIGN 8 /* bytes */ 94 95 #ifdef __LP64__ 96 static int iosize_max_clamp = 0; 97 SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW, 98 &iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX"); 99 static int devfs_iosize_max_clamp = 1; 100 SYSCTL_INT(_debug, OID_AUTO, devfs_iosize_max_clamp, CTLFLAG_RW, 101 &devfs_iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX for devices"); 102 #endif 103 104 /* 105 * Assert that the return value of read(2) and write(2) syscalls fits 106 * into a register. If not, an architecture will need to provide the 107 * usermode wrappers to reconstruct the result. 108 */ 109 CTASSERT(sizeof(register_t) >= sizeof(size_t)); 110 111 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer"); 112 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer"); 113 MALLOC_DEFINE(M_IOV, "iov", "large iov's"); 114 115 static int pollout(struct thread *, struct pollfd *, struct pollfd *, 116 u_int); 117 static int pollscan(struct thread *, struct pollfd *, u_int); 118 static int pollrescan(struct thread *); 119 static int selscan(struct thread *, fd_mask **, fd_mask **, int); 120 static int selrescan(struct thread *, fd_mask **, fd_mask **); 121 static void selfdalloc(struct thread *, void *); 122 static void selfdfree(struct seltd *, struct selfd *); 123 static int dofileread(struct thread *, int, struct file *, struct uio *, 124 off_t, int); 125 static int dofilewrite(struct thread *, int, struct file *, struct uio *, 126 off_t, int); 127 static void doselwakeup(struct selinfo *, int); 128 static void seltdinit(struct thread *); 129 static int seltdwait(struct thread *, sbintime_t, sbintime_t); 130 static void seltdclear(struct thread *); 131 132 /* 133 * One seltd per-thread allocated on demand as needed. 134 * 135 * t - protected by st_mtx 136 * k - Only accessed by curthread or read-only 137 */ 138 struct seltd { 139 STAILQ_HEAD(, selfd) st_selq; /* (k) List of selfds. */ 140 struct selfd *st_free1; /* (k) free fd for read set. */ 141 struct selfd *st_free2; /* (k) free fd for write set. */ 142 struct mtx st_mtx; /* Protects struct seltd */ 143 struct cv st_wait; /* (t) Wait channel. */ 144 int st_flags; /* (t) SELTD_ flags. */ 145 }; 146 147 #define SELTD_PENDING 0x0001 /* We have pending events. */ 148 #define SELTD_RESCAN 0x0002 /* Doing a rescan. */ 149 150 /* 151 * One selfd allocated per-thread per-file-descriptor. 152 * f - protected by sf_mtx 153 */ 154 struct selfd { 155 STAILQ_ENTRY(selfd) sf_link; /* (k) fds owned by this td. */ 156 TAILQ_ENTRY(selfd) sf_threads; /* (f) fds on this selinfo. */ 157 struct selinfo *sf_si; /* (f) selinfo when linked. */ 158 struct mtx *sf_mtx; /* Pointer to selinfo mtx. */ 159 struct seltd *sf_td; /* (k) owning seltd. */ 160 void *sf_cookie; /* (k) fd or pollfd. */ 161 }; 162 163 MALLOC_DEFINE(M_SELFD, "selfd", "selfd"); 164 static struct mtx_pool *mtxpool_select; 165 166 #ifdef __LP64__ 167 size_t 168 devfs_iosize_max(void) 169 { 170 171 return (devfs_iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ? 172 INT_MAX : SSIZE_MAX); 173 } 174 175 size_t 176 iosize_max(void) 177 { 178 179 return (iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ? 180 INT_MAX : SSIZE_MAX); 181 } 182 #endif 183 184 #ifndef _SYS_SYSPROTO_H_ 185 struct read_args { 186 int fd; 187 void *buf; 188 size_t nbyte; 189 }; 190 #endif 191 int 192 sys_read(struct thread *td, struct read_args *uap) 193 { 194 struct uio auio; 195 struct iovec aiov; 196 int error; 197 198 if (uap->nbyte > IOSIZE_MAX) 199 return (EINVAL); 200 aiov.iov_base = uap->buf; 201 aiov.iov_len = uap->nbyte; 202 auio.uio_iov = &aiov; 203 auio.uio_iovcnt = 1; 204 auio.uio_resid = uap->nbyte; 205 auio.uio_segflg = UIO_USERSPACE; 206 error = kern_readv(td, uap->fd, &auio); 207 return (error); 208 } 209 210 /* 211 * Positioned read system call 212 */ 213 #ifndef _SYS_SYSPROTO_H_ 214 struct pread_args { 215 int fd; 216 void *buf; 217 size_t nbyte; 218 int pad; 219 off_t offset; 220 }; 221 #endif 222 int 223 sys_pread(struct thread *td, struct pread_args *uap) 224 { 225 226 return (kern_pread(td, uap->fd, uap->buf, uap->nbyte, uap->offset)); 227 } 228 229 int 230 kern_pread(struct thread *td, int fd, void *buf, size_t nbyte, off_t offset) 231 { 232 struct uio auio; 233 struct iovec aiov; 234 int error; 235 236 if (nbyte > IOSIZE_MAX) 237 return (EINVAL); 238 aiov.iov_base = buf; 239 aiov.iov_len = nbyte; 240 auio.uio_iov = &aiov; 241 auio.uio_iovcnt = 1; 242 auio.uio_resid = nbyte; 243 auio.uio_segflg = UIO_USERSPACE; 244 error = kern_preadv(td, fd, &auio, offset); 245 return (error); 246 } 247 248 #if defined(COMPAT_FREEBSD6) 249 int 250 freebsd6_pread(struct thread *td, struct freebsd6_pread_args *uap) 251 { 252 253 return (kern_pread(td, uap->fd, uap->buf, uap->nbyte, uap->offset)); 254 } 255 #endif 256 257 /* 258 * Scatter read system call. 259 */ 260 #ifndef _SYS_SYSPROTO_H_ 261 struct readv_args { 262 int fd; 263 struct iovec *iovp; 264 u_int iovcnt; 265 }; 266 #endif 267 int 268 sys_readv(struct thread *td, struct readv_args *uap) 269 { 270 struct uio *auio; 271 int error; 272 273 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 274 if (error) 275 return (error); 276 error = kern_readv(td, uap->fd, auio); 277 free(auio, M_IOV); 278 return (error); 279 } 280 281 int 282 kern_readv(struct thread *td, int fd, struct uio *auio) 283 { 284 struct file *fp; 285 int error; 286 287 error = fget_read(td, fd, &cap_read_rights, &fp); 288 if (error) 289 return (error); 290 error = dofileread(td, fd, fp, auio, (off_t)-1, 0); 291 fdrop(fp, td); 292 return (error); 293 } 294 295 /* 296 * Scatter positioned read system call. 297 */ 298 #ifndef _SYS_SYSPROTO_H_ 299 struct preadv_args { 300 int fd; 301 struct iovec *iovp; 302 u_int iovcnt; 303 off_t offset; 304 }; 305 #endif 306 int 307 sys_preadv(struct thread *td, struct preadv_args *uap) 308 { 309 struct uio *auio; 310 int error; 311 312 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 313 if (error) 314 return (error); 315 error = kern_preadv(td, uap->fd, auio, uap->offset); 316 free(auio, M_IOV); 317 return (error); 318 } 319 320 int 321 kern_preadv(struct thread *td, int fd, struct uio *auio, off_t offset) 322 { 323 struct file *fp; 324 int error; 325 326 error = fget_read(td, fd, &cap_pread_rights, &fp); 327 if (error) 328 return (error); 329 if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE)) 330 error = ESPIPE; 331 else if (offset < 0 && 332 (fp->f_vnode == NULL || fp->f_vnode->v_type != VCHR)) 333 error = EINVAL; 334 else 335 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET); 336 fdrop(fp, td); 337 return (error); 338 } 339 340 /* 341 * Common code for readv and preadv that reads data in 342 * from a file using the passed in uio, offset, and flags. 343 */ 344 static int 345 dofileread(struct thread *td, int fd, struct file *fp, struct uio *auio, 346 off_t offset, int flags) 347 { 348 ssize_t cnt; 349 int error; 350 #ifdef KTRACE 351 struct uio *ktruio = NULL; 352 #endif 353 354 AUDIT_ARG_FD(fd); 355 356 /* Finish zero length reads right here */ 357 if (auio->uio_resid == 0) { 358 td->td_retval[0] = 0; 359 return (0); 360 } 361 auio->uio_rw = UIO_READ; 362 auio->uio_offset = offset; 363 auio->uio_td = td; 364 #ifdef KTRACE 365 if (KTRPOINT(td, KTR_GENIO)) 366 ktruio = cloneuio(auio); 367 #endif 368 cnt = auio->uio_resid; 369 if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) { 370 if (auio->uio_resid != cnt && (error == ERESTART || 371 error == EINTR || error == EWOULDBLOCK)) 372 error = 0; 373 } 374 cnt -= auio->uio_resid; 375 #ifdef KTRACE 376 if (ktruio != NULL) { 377 ktruio->uio_resid = cnt; 378 ktrgenio(fd, UIO_READ, ktruio, error); 379 } 380 #endif 381 td->td_retval[0] = cnt; 382 return (error); 383 } 384 385 #ifndef _SYS_SYSPROTO_H_ 386 struct write_args { 387 int fd; 388 const void *buf; 389 size_t nbyte; 390 }; 391 #endif 392 int 393 sys_write(struct thread *td, struct write_args *uap) 394 { 395 struct uio auio; 396 struct iovec aiov; 397 int error; 398 399 if (uap->nbyte > IOSIZE_MAX) 400 return (EINVAL); 401 aiov.iov_base = (void *)(uintptr_t)uap->buf; 402 aiov.iov_len = uap->nbyte; 403 auio.uio_iov = &aiov; 404 auio.uio_iovcnt = 1; 405 auio.uio_resid = uap->nbyte; 406 auio.uio_segflg = UIO_USERSPACE; 407 error = kern_writev(td, uap->fd, &auio); 408 return (error); 409 } 410 411 /* 412 * Positioned write system call. 413 */ 414 #ifndef _SYS_SYSPROTO_H_ 415 struct pwrite_args { 416 int fd; 417 const void *buf; 418 size_t nbyte; 419 int pad; 420 off_t offset; 421 }; 422 #endif 423 int 424 sys_pwrite(struct thread *td, struct pwrite_args *uap) 425 { 426 427 return (kern_pwrite(td, uap->fd, uap->buf, uap->nbyte, uap->offset)); 428 } 429 430 int 431 kern_pwrite(struct thread *td, int fd, const void *buf, size_t nbyte, 432 off_t offset) 433 { 434 struct uio auio; 435 struct iovec aiov; 436 int error; 437 438 if (nbyte > IOSIZE_MAX) 439 return (EINVAL); 440 aiov.iov_base = (void *)(uintptr_t)buf; 441 aiov.iov_len = nbyte; 442 auio.uio_iov = &aiov; 443 auio.uio_iovcnt = 1; 444 auio.uio_resid = nbyte; 445 auio.uio_segflg = UIO_USERSPACE; 446 error = kern_pwritev(td, fd, &auio, offset); 447 return (error); 448 } 449 450 #if defined(COMPAT_FREEBSD6) 451 int 452 freebsd6_pwrite(struct thread *td, struct freebsd6_pwrite_args *uap) 453 { 454 455 return (kern_pwrite(td, uap->fd, uap->buf, uap->nbyte, uap->offset)); 456 } 457 #endif 458 459 /* 460 * Gather write system call. 461 */ 462 #ifndef _SYS_SYSPROTO_H_ 463 struct writev_args { 464 int fd; 465 struct iovec *iovp; 466 u_int iovcnt; 467 }; 468 #endif 469 int 470 sys_writev(struct thread *td, struct writev_args *uap) 471 { 472 struct uio *auio; 473 int error; 474 475 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 476 if (error) 477 return (error); 478 error = kern_writev(td, uap->fd, auio); 479 free(auio, M_IOV); 480 return (error); 481 } 482 483 int 484 kern_writev(struct thread *td, int fd, struct uio *auio) 485 { 486 struct file *fp; 487 int error; 488 489 error = fget_write(td, fd, &cap_write_rights, &fp); 490 if (error) 491 return (error); 492 error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0); 493 fdrop(fp, td); 494 return (error); 495 } 496 497 /* 498 * Gather positioned write system call. 499 */ 500 #ifndef _SYS_SYSPROTO_H_ 501 struct pwritev_args { 502 int fd; 503 struct iovec *iovp; 504 u_int iovcnt; 505 off_t offset; 506 }; 507 #endif 508 int 509 sys_pwritev(struct thread *td, struct pwritev_args *uap) 510 { 511 struct uio *auio; 512 int error; 513 514 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 515 if (error) 516 return (error); 517 error = kern_pwritev(td, uap->fd, auio, uap->offset); 518 free(auio, M_IOV); 519 return (error); 520 } 521 522 int 523 kern_pwritev(struct thread *td, int fd, struct uio *auio, off_t offset) 524 { 525 struct file *fp; 526 int error; 527 528 error = fget_write(td, fd, &cap_pwrite_rights, &fp); 529 if (error) 530 return (error); 531 if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE)) 532 error = ESPIPE; 533 else if (offset < 0 && 534 (fp->f_vnode == NULL || fp->f_vnode->v_type != VCHR)) 535 error = EINVAL; 536 else 537 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET); 538 fdrop(fp, td); 539 return (error); 540 } 541 542 /* 543 * Common code for writev and pwritev that writes data to 544 * a file using the passed in uio, offset, and flags. 545 */ 546 static int 547 dofilewrite(struct thread *td, int fd, struct file *fp, struct uio *auio, 548 off_t offset, int flags) 549 { 550 ssize_t cnt; 551 int error; 552 #ifdef KTRACE 553 struct uio *ktruio = NULL; 554 #endif 555 556 AUDIT_ARG_FD(fd); 557 auio->uio_rw = UIO_WRITE; 558 auio->uio_td = td; 559 auio->uio_offset = offset; 560 #ifdef KTRACE 561 if (KTRPOINT(td, KTR_GENIO)) 562 ktruio = cloneuio(auio); 563 #endif 564 cnt = auio->uio_resid; 565 if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) { 566 if (auio->uio_resid != cnt && (error == ERESTART || 567 error == EINTR || error == EWOULDBLOCK)) 568 error = 0; 569 /* Socket layer is responsible for issuing SIGPIPE. */ 570 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) { 571 PROC_LOCK(td->td_proc); 572 tdsignal(td, SIGPIPE); 573 PROC_UNLOCK(td->td_proc); 574 } 575 } 576 cnt -= auio->uio_resid; 577 #ifdef KTRACE 578 if (ktruio != NULL) { 579 ktruio->uio_resid = cnt; 580 ktrgenio(fd, UIO_WRITE, ktruio, error); 581 } 582 #endif 583 td->td_retval[0] = cnt; 584 return (error); 585 } 586 587 /* 588 * Truncate a file given a file descriptor. 589 * 590 * Can't use fget_write() here, since must return EINVAL and not EBADF if the 591 * descriptor isn't writable. 592 */ 593 int 594 kern_ftruncate(struct thread *td, int fd, off_t length) 595 { 596 struct file *fp; 597 int error; 598 599 AUDIT_ARG_FD(fd); 600 if (length < 0) 601 return (EINVAL); 602 error = fget(td, fd, &cap_ftruncate_rights, &fp); 603 if (error) 604 return (error); 605 AUDIT_ARG_FILE(td->td_proc, fp); 606 if (!(fp->f_flag & FWRITE)) { 607 fdrop(fp, td); 608 return (EINVAL); 609 } 610 error = fo_truncate(fp, length, td->td_ucred, td); 611 fdrop(fp, td); 612 return (error); 613 } 614 615 #ifndef _SYS_SYSPROTO_H_ 616 struct ftruncate_args { 617 int fd; 618 int pad; 619 off_t length; 620 }; 621 #endif 622 int 623 sys_ftruncate(struct thread *td, struct ftruncate_args *uap) 624 { 625 626 return (kern_ftruncate(td, uap->fd, uap->length)); 627 } 628 629 #if defined(COMPAT_43) 630 #ifndef _SYS_SYSPROTO_H_ 631 struct oftruncate_args { 632 int fd; 633 long length; 634 }; 635 #endif 636 int 637 oftruncate(struct thread *td, struct oftruncate_args *uap) 638 { 639 640 return (kern_ftruncate(td, uap->fd, uap->length)); 641 } 642 #endif /* COMPAT_43 */ 643 644 #ifndef _SYS_SYSPROTO_H_ 645 struct ioctl_args { 646 int fd; 647 u_long com; 648 caddr_t data; 649 }; 650 #endif 651 /* ARGSUSED */ 652 int 653 sys_ioctl(struct thread *td, struct ioctl_args *uap) 654 { 655 u_char smalldata[SYS_IOCTL_SMALL_SIZE] __aligned(SYS_IOCTL_SMALL_ALIGN); 656 uint32_t com; 657 int arg, error; 658 u_int size; 659 caddr_t data; 660 661 #ifdef INVARIANTS 662 if (uap->com > 0xffffffff) { 663 printf( 664 "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n", 665 td->td_proc->p_pid, td->td_name, uap->com); 666 } 667 #endif 668 com = (uint32_t)uap->com; 669 670 /* 671 * Interpret high order word to find amount of data to be 672 * copied to/from the user's address space. 673 */ 674 size = IOCPARM_LEN(com); 675 if ((size > IOCPARM_MAX) || 676 ((com & (IOC_VOID | IOC_IN | IOC_OUT)) == 0) || 677 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43) 678 ((com & IOC_OUT) && size == 0) || 679 #else 680 ((com & (IOC_IN | IOC_OUT)) && size == 0) || 681 #endif 682 ((com & IOC_VOID) && size > 0 && size != sizeof(int))) 683 return (ENOTTY); 684 685 if (size > 0) { 686 if (com & IOC_VOID) { 687 /* Integer argument. */ 688 arg = (intptr_t)uap->data; 689 data = (void *)&arg; 690 size = 0; 691 } else { 692 if (size > SYS_IOCTL_SMALL_SIZE) 693 data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK); 694 else 695 data = smalldata; 696 } 697 } else 698 data = (void *)&uap->data; 699 if (com & IOC_IN) { 700 error = copyin(uap->data, data, (u_int)size); 701 if (error != 0) 702 goto out; 703 } else if (com & IOC_OUT) { 704 /* 705 * Zero the buffer so the user always 706 * gets back something deterministic. 707 */ 708 bzero(data, size); 709 } 710 711 error = kern_ioctl(td, uap->fd, com, data); 712 713 if (error == 0 && (com & IOC_OUT)) 714 error = copyout(data, uap->data, (u_int)size); 715 716 out: 717 if (size > SYS_IOCTL_SMALL_SIZE) 718 free(data, M_IOCTLOPS); 719 return (error); 720 } 721 722 int 723 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data) 724 { 725 struct file *fp; 726 struct filedesc *fdp; 727 int error, tmp, locked; 728 729 AUDIT_ARG_FD(fd); 730 AUDIT_ARG_CMD(com); 731 732 fdp = td->td_proc->p_fd; 733 734 switch (com) { 735 case FIONCLEX: 736 case FIOCLEX: 737 FILEDESC_XLOCK(fdp); 738 locked = LA_XLOCKED; 739 break; 740 default: 741 #ifdef CAPABILITIES 742 FILEDESC_SLOCK(fdp); 743 locked = LA_SLOCKED; 744 #else 745 locked = LA_UNLOCKED; 746 #endif 747 break; 748 } 749 750 #ifdef CAPABILITIES 751 if ((fp = fget_locked(fdp, fd)) == NULL) { 752 error = EBADF; 753 goto out; 754 } 755 if ((error = cap_ioctl_check(fdp, fd, com)) != 0) { 756 fp = NULL; /* fhold() was not called yet */ 757 goto out; 758 } 759 if (!fhold(fp)) { 760 error = EBADF; 761 fp = NULL; 762 goto out; 763 } 764 if (locked == LA_SLOCKED) { 765 FILEDESC_SUNLOCK(fdp); 766 locked = LA_UNLOCKED; 767 } 768 #else 769 error = fget(td, fd, &cap_ioctl_rights, &fp); 770 if (error != 0) { 771 fp = NULL; 772 goto out; 773 } 774 #endif 775 if ((fp->f_flag & (FREAD | FWRITE)) == 0) { 776 error = EBADF; 777 goto out; 778 } 779 780 switch (com) { 781 case FIONCLEX: 782 fdp->fd_ofiles[fd].fde_flags &= ~UF_EXCLOSE; 783 goto out; 784 case FIOCLEX: 785 fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE; 786 goto out; 787 case FIONBIO: 788 if ((tmp = *(int *)data)) 789 atomic_set_int(&fp->f_flag, FNONBLOCK); 790 else 791 atomic_clear_int(&fp->f_flag, FNONBLOCK); 792 data = (void *)&tmp; 793 break; 794 case FIOASYNC: 795 if ((tmp = *(int *)data)) 796 atomic_set_int(&fp->f_flag, FASYNC); 797 else 798 atomic_clear_int(&fp->f_flag, FASYNC); 799 data = (void *)&tmp; 800 break; 801 } 802 803 error = fo_ioctl(fp, com, data, td->td_ucred, td); 804 out: 805 switch (locked) { 806 case LA_XLOCKED: 807 FILEDESC_XUNLOCK(fdp); 808 break; 809 #ifdef CAPABILITIES 810 case LA_SLOCKED: 811 FILEDESC_SUNLOCK(fdp); 812 break; 813 #endif 814 default: 815 FILEDESC_UNLOCK_ASSERT(fdp); 816 break; 817 } 818 if (fp != NULL) 819 fdrop(fp, td); 820 return (error); 821 } 822 823 int 824 sys_posix_fallocate(struct thread *td, struct posix_fallocate_args *uap) 825 { 826 int error; 827 828 error = kern_posix_fallocate(td, uap->fd, uap->offset, uap->len); 829 return (kern_posix_error(td, error)); 830 } 831 832 int 833 kern_posix_fallocate(struct thread *td, int fd, off_t offset, off_t len) 834 { 835 struct file *fp; 836 int error; 837 838 AUDIT_ARG_FD(fd); 839 if (offset < 0 || len <= 0) 840 return (EINVAL); 841 /* Check for wrap. */ 842 if (offset > OFF_MAX - len) 843 return (EFBIG); 844 AUDIT_ARG_FD(fd); 845 error = fget(td, fd, &cap_pwrite_rights, &fp); 846 if (error != 0) 847 return (error); 848 AUDIT_ARG_FILE(td->td_proc, fp); 849 if ((fp->f_ops->fo_flags & DFLAG_SEEKABLE) == 0) { 850 error = ESPIPE; 851 goto out; 852 } 853 if ((fp->f_flag & FWRITE) == 0) { 854 error = EBADF; 855 goto out; 856 } 857 858 error = fo_fallocate(fp, offset, len, td); 859 out: 860 fdrop(fp, td); 861 return (error); 862 } 863 864 int 865 kern_specialfd(struct thread *td, int type, void *arg) 866 { 867 struct file *fp; 868 struct specialfd_eventfd *ae; 869 int error, fd, fflags; 870 871 fflags = 0; 872 error = falloc_noinstall(td, &fp); 873 if (error != 0) 874 return (error); 875 876 switch (type) { 877 case SPECIALFD_EVENTFD: 878 ae = arg; 879 if ((ae->flags & EFD_CLOEXEC) != 0) 880 fflags |= O_CLOEXEC; 881 error = eventfd_create_file(td, fp, ae->initval, ae->flags); 882 break; 883 default: 884 error = EINVAL; 885 break; 886 } 887 888 if (error == 0) 889 error = finstall(td, fp, &fd, fflags, NULL); 890 fdrop(fp, td); 891 if (error == 0) 892 td->td_retval[0] = fd; 893 return (error); 894 } 895 896 int 897 sys___specialfd(struct thread *td, struct __specialfd_args *args) 898 { 899 struct specialfd_eventfd ae; 900 int error; 901 902 switch (args->type) { 903 case SPECIALFD_EVENTFD: 904 if (args->len != sizeof(struct specialfd_eventfd)) { 905 error = EINVAL; 906 break; 907 } 908 error = copyin(args->req, &ae, sizeof(ae)); 909 if (error != 0) 910 break; 911 if ((ae.flags & ~(EFD_CLOEXEC | EFD_NONBLOCK | 912 EFD_SEMAPHORE)) != 0) { 913 error = EINVAL; 914 break; 915 } 916 error = kern_specialfd(td, args->type, &ae); 917 break; 918 default: 919 error = EINVAL; 920 break; 921 } 922 return (error); 923 } 924 925 int 926 poll_no_poll(int events) 927 { 928 /* 929 * Return true for read/write. If the user asked for something 930 * special, return POLLNVAL, so that clients have a way of 931 * determining reliably whether or not the extended 932 * functionality is present without hard-coding knowledge 933 * of specific filesystem implementations. 934 */ 935 if (events & ~POLLSTANDARD) 936 return (POLLNVAL); 937 938 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 939 } 940 941 int 942 sys_pselect(struct thread *td, struct pselect_args *uap) 943 { 944 struct timespec ts; 945 struct timeval tv, *tvp; 946 sigset_t set, *uset; 947 int error; 948 949 if (uap->ts != NULL) { 950 error = copyin(uap->ts, &ts, sizeof(ts)); 951 if (error != 0) 952 return (error); 953 TIMESPEC_TO_TIMEVAL(&tv, &ts); 954 tvp = &tv; 955 } else 956 tvp = NULL; 957 if (uap->sm != NULL) { 958 error = copyin(uap->sm, &set, sizeof(set)); 959 if (error != 0) 960 return (error); 961 uset = &set; 962 } else 963 uset = NULL; 964 return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp, 965 uset, NFDBITS)); 966 } 967 968 int 969 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex, 970 struct timeval *tvp, sigset_t *uset, int abi_nfdbits) 971 { 972 int error; 973 974 if (uset != NULL) { 975 error = kern_sigprocmask(td, SIG_SETMASK, uset, 976 &td->td_oldsigmask, 0); 977 if (error != 0) 978 return (error); 979 td->td_pflags |= TDP_OLDMASK; 980 /* 981 * Make sure that ast() is called on return to 982 * usermode and TDP_OLDMASK is cleared, restoring old 983 * sigmask. 984 */ 985 thread_lock(td); 986 td->td_flags |= TDF_ASTPENDING; 987 thread_unlock(td); 988 } 989 error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits); 990 return (error); 991 } 992 993 #ifndef _SYS_SYSPROTO_H_ 994 struct select_args { 995 int nd; 996 fd_set *in, *ou, *ex; 997 struct timeval *tv; 998 }; 999 #endif 1000 int 1001 sys_select(struct thread *td, struct select_args *uap) 1002 { 1003 struct timeval tv, *tvp; 1004 int error; 1005 1006 if (uap->tv != NULL) { 1007 error = copyin(uap->tv, &tv, sizeof(tv)); 1008 if (error) 1009 return (error); 1010 tvp = &tv; 1011 } else 1012 tvp = NULL; 1013 1014 return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp, 1015 NFDBITS)); 1016 } 1017 1018 /* 1019 * In the unlikely case when user specified n greater then the last 1020 * open file descriptor, check that no bits are set after the last 1021 * valid fd. We must return EBADF if any is set. 1022 * 1023 * There are applications that rely on the behaviour. 1024 * 1025 * nd is fd_nfiles. 1026 */ 1027 static int 1028 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits) 1029 { 1030 char *addr, *oaddr; 1031 int b, i, res; 1032 uint8_t bits; 1033 1034 if (nd >= ndu || fd_in == NULL) 1035 return (0); 1036 1037 oaddr = NULL; 1038 bits = 0; /* silence gcc */ 1039 for (i = nd; i < ndu; i++) { 1040 b = i / NBBY; 1041 #if BYTE_ORDER == LITTLE_ENDIAN 1042 addr = (char *)fd_in + b; 1043 #else 1044 addr = (char *)fd_in; 1045 if (abi_nfdbits == NFDBITS) { 1046 addr += rounddown(b, sizeof(fd_mask)) + 1047 sizeof(fd_mask) - 1 - b % sizeof(fd_mask); 1048 } else { 1049 addr += rounddown(b, sizeof(uint32_t)) + 1050 sizeof(uint32_t) - 1 - b % sizeof(uint32_t); 1051 } 1052 #endif 1053 if (addr != oaddr) { 1054 res = fubyte(addr); 1055 if (res == -1) 1056 return (EFAULT); 1057 oaddr = addr; 1058 bits = res; 1059 } 1060 if ((bits & (1 << (i % NBBY))) != 0) 1061 return (EBADF); 1062 } 1063 return (0); 1064 } 1065 1066 int 1067 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou, 1068 fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits) 1069 { 1070 struct filedesc *fdp; 1071 /* 1072 * The magic 2048 here is chosen to be just enough for FD_SETSIZE 1073 * infds with the new FD_SETSIZE of 1024, and more than enough for 1074 * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE 1075 * of 256. 1076 */ 1077 fd_mask s_selbits[howmany(2048, NFDBITS)]; 1078 fd_mask *ibits[3], *obits[3], *selbits, *sbp; 1079 struct timeval rtv; 1080 sbintime_t asbt, precision, rsbt; 1081 u_int nbufbytes, ncpbytes, ncpubytes, nfdbits; 1082 int error, lf, ndu; 1083 1084 if (nd < 0) 1085 return (EINVAL); 1086 fdp = td->td_proc->p_fd; 1087 ndu = nd; 1088 lf = fdp->fd_nfiles; 1089 if (nd > lf) 1090 nd = lf; 1091 1092 error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits); 1093 if (error != 0) 1094 return (error); 1095 error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits); 1096 if (error != 0) 1097 return (error); 1098 error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits); 1099 if (error != 0) 1100 return (error); 1101 1102 /* 1103 * Allocate just enough bits for the non-null fd_sets. Use the 1104 * preallocated auto buffer if possible. 1105 */ 1106 nfdbits = roundup(nd, NFDBITS); 1107 ncpbytes = nfdbits / NBBY; 1108 ncpubytes = roundup(nd, abi_nfdbits) / NBBY; 1109 nbufbytes = 0; 1110 if (fd_in != NULL) 1111 nbufbytes += 2 * ncpbytes; 1112 if (fd_ou != NULL) 1113 nbufbytes += 2 * ncpbytes; 1114 if (fd_ex != NULL) 1115 nbufbytes += 2 * ncpbytes; 1116 if (nbufbytes <= sizeof s_selbits) 1117 selbits = &s_selbits[0]; 1118 else 1119 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK); 1120 1121 /* 1122 * Assign pointers into the bit buffers and fetch the input bits. 1123 * Put the output buffers together so that they can be bzeroed 1124 * together. 1125 */ 1126 sbp = selbits; 1127 #define getbits(name, x) \ 1128 do { \ 1129 if (name == NULL) { \ 1130 ibits[x] = NULL; \ 1131 obits[x] = NULL; \ 1132 } else { \ 1133 ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp; \ 1134 obits[x] = sbp; \ 1135 sbp += ncpbytes / sizeof *sbp; \ 1136 error = copyin(name, ibits[x], ncpubytes); \ 1137 if (error != 0) \ 1138 goto done; \ 1139 if (ncpbytes != ncpubytes) \ 1140 bzero((char *)ibits[x] + ncpubytes, \ 1141 ncpbytes - ncpubytes); \ 1142 } \ 1143 } while (0) 1144 getbits(fd_in, 0); 1145 getbits(fd_ou, 1); 1146 getbits(fd_ex, 2); 1147 #undef getbits 1148 1149 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__) 1150 /* 1151 * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS, 1152 * we are running under 32-bit emulation. This should be more 1153 * generic. 1154 */ 1155 #define swizzle_fdset(bits) \ 1156 if (abi_nfdbits != NFDBITS && bits != NULL) { \ 1157 int i; \ 1158 for (i = 0; i < ncpbytes / sizeof *sbp; i++) \ 1159 bits[i] = (bits[i] >> 32) | (bits[i] << 32); \ 1160 } 1161 #else 1162 #define swizzle_fdset(bits) 1163 #endif 1164 1165 /* Make sure the bit order makes it through an ABI transition */ 1166 swizzle_fdset(ibits[0]); 1167 swizzle_fdset(ibits[1]); 1168 swizzle_fdset(ibits[2]); 1169 1170 if (nbufbytes != 0) 1171 bzero(selbits, nbufbytes / 2); 1172 1173 precision = 0; 1174 if (tvp != NULL) { 1175 rtv = *tvp; 1176 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 || 1177 rtv.tv_usec >= 1000000) { 1178 error = EINVAL; 1179 goto done; 1180 } 1181 if (!timevalisset(&rtv)) 1182 asbt = 0; 1183 else if (rtv.tv_sec <= INT32_MAX) { 1184 rsbt = tvtosbt(rtv); 1185 precision = rsbt; 1186 precision >>= tc_precexp; 1187 if (TIMESEL(&asbt, rsbt)) 1188 asbt += tc_tick_sbt; 1189 if (asbt <= SBT_MAX - rsbt) 1190 asbt += rsbt; 1191 else 1192 asbt = -1; 1193 } else 1194 asbt = -1; 1195 } else 1196 asbt = -1; 1197 seltdinit(td); 1198 /* Iterate until the timeout expires or descriptors become ready. */ 1199 for (;;) { 1200 error = selscan(td, ibits, obits, nd); 1201 if (error || td->td_retval[0] != 0) 1202 break; 1203 error = seltdwait(td, asbt, precision); 1204 if (error) 1205 break; 1206 error = selrescan(td, ibits, obits); 1207 if (error || td->td_retval[0] != 0) 1208 break; 1209 } 1210 seltdclear(td); 1211 1212 done: 1213 /* select is not restarted after signals... */ 1214 if (error == ERESTART) 1215 error = EINTR; 1216 if (error == EWOULDBLOCK) 1217 error = 0; 1218 1219 /* swizzle bit order back, if necessary */ 1220 swizzle_fdset(obits[0]); 1221 swizzle_fdset(obits[1]); 1222 swizzle_fdset(obits[2]); 1223 #undef swizzle_fdset 1224 1225 #define putbits(name, x) \ 1226 if (name && (error2 = copyout(obits[x], name, ncpubytes))) \ 1227 error = error2; 1228 if (error == 0) { 1229 int error2; 1230 1231 putbits(fd_in, 0); 1232 putbits(fd_ou, 1); 1233 putbits(fd_ex, 2); 1234 #undef putbits 1235 } 1236 if (selbits != &s_selbits[0]) 1237 free(selbits, M_SELECT); 1238 1239 return (error); 1240 } 1241 /* 1242 * Convert a select bit set to poll flags. 1243 * 1244 * The backend always returns POLLHUP/POLLERR if appropriate and we 1245 * return this as a set bit in any set. 1246 */ 1247 static int select_flags[3] = { 1248 POLLRDNORM | POLLHUP | POLLERR, 1249 POLLWRNORM | POLLHUP | POLLERR, 1250 POLLRDBAND | POLLERR 1251 }; 1252 1253 /* 1254 * Compute the fo_poll flags required for a fd given by the index and 1255 * bit position in the fd_mask array. 1256 */ 1257 static __inline int 1258 selflags(fd_mask **ibits, int idx, fd_mask bit) 1259 { 1260 int flags; 1261 int msk; 1262 1263 flags = 0; 1264 for (msk = 0; msk < 3; msk++) { 1265 if (ibits[msk] == NULL) 1266 continue; 1267 if ((ibits[msk][idx] & bit) == 0) 1268 continue; 1269 flags |= select_flags[msk]; 1270 } 1271 return (flags); 1272 } 1273 1274 /* 1275 * Set the appropriate output bits given a mask of fired events and the 1276 * input bits originally requested. 1277 */ 1278 static __inline int 1279 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events) 1280 { 1281 int msk; 1282 int n; 1283 1284 n = 0; 1285 for (msk = 0; msk < 3; msk++) { 1286 if ((events & select_flags[msk]) == 0) 1287 continue; 1288 if (ibits[msk] == NULL) 1289 continue; 1290 if ((ibits[msk][idx] & bit) == 0) 1291 continue; 1292 /* 1293 * XXX Check for a duplicate set. This can occur because a 1294 * socket calls selrecord() twice for each poll() call 1295 * resulting in two selfds per real fd. selrescan() will 1296 * call selsetbits twice as a result. 1297 */ 1298 if ((obits[msk][idx] & bit) != 0) 1299 continue; 1300 obits[msk][idx] |= bit; 1301 n++; 1302 } 1303 1304 return (n); 1305 } 1306 1307 /* 1308 * Traverse the list of fds attached to this thread's seltd and check for 1309 * completion. 1310 */ 1311 static int 1312 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits) 1313 { 1314 struct filedesc *fdp; 1315 struct selinfo *si; 1316 struct seltd *stp; 1317 struct selfd *sfp; 1318 struct selfd *sfn; 1319 struct file *fp; 1320 fd_mask bit; 1321 int fd, ev, n, idx; 1322 int error; 1323 bool only_user; 1324 1325 fdp = td->td_proc->p_fd; 1326 stp = td->td_sel; 1327 n = 0; 1328 only_user = FILEDESC_IS_ONLY_USER(fdp); 1329 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) { 1330 fd = (int)(uintptr_t)sfp->sf_cookie; 1331 si = sfp->sf_si; 1332 selfdfree(stp, sfp); 1333 /* If the selinfo wasn't cleared the event didn't fire. */ 1334 if (si != NULL) 1335 continue; 1336 if (only_user) 1337 error = fget_only_user(fdp, fd, &cap_event_rights, &fp); 1338 else 1339 error = fget_unlocked(fdp, fd, &cap_event_rights, &fp); 1340 if (__predict_false(error != 0)) 1341 return (error); 1342 idx = fd / NFDBITS; 1343 bit = (fd_mask)1 << (fd % NFDBITS); 1344 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td); 1345 if (only_user) 1346 fput_only_user(fdp, fp); 1347 else 1348 fdrop(fp, td); 1349 if (ev != 0) 1350 n += selsetbits(ibits, obits, idx, bit, ev); 1351 } 1352 stp->st_flags = 0; 1353 td->td_retval[0] = n; 1354 return (0); 1355 } 1356 1357 /* 1358 * Perform the initial filedescriptor scan and register ourselves with 1359 * each selinfo. 1360 */ 1361 static int 1362 selscan(struct thread *td, fd_mask **ibits, fd_mask **obits, int nfd) 1363 { 1364 struct filedesc *fdp; 1365 struct file *fp; 1366 fd_mask bit; 1367 int ev, flags, end, fd; 1368 int n, idx; 1369 int error; 1370 bool only_user; 1371 1372 fdp = td->td_proc->p_fd; 1373 n = 0; 1374 only_user = FILEDESC_IS_ONLY_USER(fdp); 1375 for (idx = 0, fd = 0; fd < nfd; idx++) { 1376 end = imin(fd + NFDBITS, nfd); 1377 for (bit = 1; fd < end; bit <<= 1, fd++) { 1378 /* Compute the list of events we're interested in. */ 1379 flags = selflags(ibits, idx, bit); 1380 if (flags == 0) 1381 continue; 1382 if (only_user) 1383 error = fget_only_user(fdp, fd, &cap_event_rights, &fp); 1384 else 1385 error = fget_unlocked(fdp, fd, &cap_event_rights, &fp); 1386 if (__predict_false(error != 0)) 1387 return (error); 1388 selfdalloc(td, (void *)(uintptr_t)fd); 1389 ev = fo_poll(fp, flags, td->td_ucred, td); 1390 if (only_user) 1391 fput_only_user(fdp, fp); 1392 else 1393 fdrop(fp, td); 1394 if (ev != 0) 1395 n += selsetbits(ibits, obits, idx, bit, ev); 1396 } 1397 } 1398 1399 td->td_retval[0] = n; 1400 return (0); 1401 } 1402 1403 int 1404 sys_poll(struct thread *td, struct poll_args *uap) 1405 { 1406 struct timespec ts, *tsp; 1407 1408 if (uap->timeout != INFTIM) { 1409 if (uap->timeout < 0) 1410 return (EINVAL); 1411 ts.tv_sec = uap->timeout / 1000; 1412 ts.tv_nsec = (uap->timeout % 1000) * 1000000; 1413 tsp = &ts; 1414 } else 1415 tsp = NULL; 1416 1417 return (kern_poll(td, uap->fds, uap->nfds, tsp, NULL)); 1418 } 1419 1420 int 1421 kern_poll(struct thread *td, struct pollfd *ufds, u_int nfds, 1422 struct timespec *tsp, sigset_t *uset) 1423 { 1424 struct pollfd *kfds; 1425 struct pollfd stackfds[32]; 1426 sbintime_t sbt, precision, tmp; 1427 time_t over; 1428 struct timespec ts; 1429 int error; 1430 1431 precision = 0; 1432 if (tsp != NULL) { 1433 if (tsp->tv_sec < 0) 1434 return (EINVAL); 1435 if (tsp->tv_nsec < 0 || tsp->tv_nsec >= 1000000000) 1436 return (EINVAL); 1437 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) 1438 sbt = 0; 1439 else { 1440 ts = *tsp; 1441 if (ts.tv_sec > INT32_MAX / 2) { 1442 over = ts.tv_sec - INT32_MAX / 2; 1443 ts.tv_sec -= over; 1444 } else 1445 over = 0; 1446 tmp = tstosbt(ts); 1447 precision = tmp; 1448 precision >>= tc_precexp; 1449 if (TIMESEL(&sbt, tmp)) 1450 sbt += tc_tick_sbt; 1451 sbt += tmp; 1452 } 1453 } else 1454 sbt = -1; 1455 1456 /* 1457 * This is kinda bogus. We have fd limits, but that is not 1458 * really related to the size of the pollfd array. Make sure 1459 * we let the process use at least FD_SETSIZE entries and at 1460 * least enough for the system-wide limits. We want to be reasonably 1461 * safe, but not overly restrictive. 1462 */ 1463 if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 1464 return (EINVAL); 1465 if (nfds > nitems(stackfds)) 1466 kfds = mallocarray(nfds, sizeof(*kfds), M_TEMP, M_WAITOK); 1467 else 1468 kfds = stackfds; 1469 error = copyin(ufds, kfds, nfds * sizeof(*kfds)); 1470 if (error) 1471 goto done; 1472 1473 if (uset != NULL) { 1474 error = kern_sigprocmask(td, SIG_SETMASK, uset, 1475 &td->td_oldsigmask, 0); 1476 if (error) 1477 goto done; 1478 td->td_pflags |= TDP_OLDMASK; 1479 /* 1480 * Make sure that ast() is called on return to 1481 * usermode and TDP_OLDMASK is cleared, restoring old 1482 * sigmask. 1483 */ 1484 thread_lock(td); 1485 td->td_flags |= TDF_ASTPENDING; 1486 thread_unlock(td); 1487 } 1488 1489 seltdinit(td); 1490 /* Iterate until the timeout expires or descriptors become ready. */ 1491 for (;;) { 1492 error = pollscan(td, kfds, nfds); 1493 if (error || td->td_retval[0] != 0) 1494 break; 1495 error = seltdwait(td, sbt, precision); 1496 if (error) 1497 break; 1498 error = pollrescan(td); 1499 if (error || td->td_retval[0] != 0) 1500 break; 1501 } 1502 seltdclear(td); 1503 1504 done: 1505 /* poll is not restarted after signals... */ 1506 if (error == ERESTART) 1507 error = EINTR; 1508 if (error == EWOULDBLOCK) 1509 error = 0; 1510 if (error == 0) { 1511 error = pollout(td, kfds, ufds, nfds); 1512 if (error) 1513 goto out; 1514 } 1515 out: 1516 if (nfds > nitems(stackfds)) 1517 free(kfds, M_TEMP); 1518 return (error); 1519 } 1520 1521 int 1522 sys_ppoll(struct thread *td, struct ppoll_args *uap) 1523 { 1524 struct timespec ts, *tsp; 1525 sigset_t set, *ssp; 1526 int error; 1527 1528 if (uap->ts != NULL) { 1529 error = copyin(uap->ts, &ts, sizeof(ts)); 1530 if (error) 1531 return (error); 1532 tsp = &ts; 1533 } else 1534 tsp = NULL; 1535 if (uap->set != NULL) { 1536 error = copyin(uap->set, &set, sizeof(set)); 1537 if (error) 1538 return (error); 1539 ssp = &set; 1540 } else 1541 ssp = NULL; 1542 /* 1543 * fds is still a pointer to user space. kern_poll() will 1544 * take care of copyin that array to the kernel space. 1545 */ 1546 1547 return (kern_poll(td, uap->fds, uap->nfds, tsp, ssp)); 1548 } 1549 1550 static int 1551 pollrescan(struct thread *td) 1552 { 1553 struct seltd *stp; 1554 struct selfd *sfp; 1555 struct selfd *sfn; 1556 struct selinfo *si; 1557 struct filedesc *fdp; 1558 struct file *fp; 1559 struct pollfd *fd; 1560 int n, error; 1561 bool only_user; 1562 1563 n = 0; 1564 fdp = td->td_proc->p_fd; 1565 stp = td->td_sel; 1566 only_user = FILEDESC_IS_ONLY_USER(fdp); 1567 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) { 1568 fd = (struct pollfd *)sfp->sf_cookie; 1569 si = sfp->sf_si; 1570 selfdfree(stp, sfp); 1571 /* If the selinfo wasn't cleared the event didn't fire. */ 1572 if (si != NULL) 1573 continue; 1574 if (only_user) 1575 error = fget_only_user(fdp, fd->fd, &cap_event_rights, &fp); 1576 else 1577 error = fget_unlocked(fdp, fd->fd, &cap_event_rights, &fp); 1578 if (__predict_false(error != 0)) { 1579 fd->revents = POLLNVAL; 1580 n++; 1581 continue; 1582 } 1583 /* 1584 * Note: backend also returns POLLHUP and 1585 * POLLERR if appropriate. 1586 */ 1587 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td); 1588 if (only_user) 1589 fput_only_user(fdp, fp); 1590 else 1591 fdrop(fp, td); 1592 if (fd->revents != 0) 1593 n++; 1594 } 1595 stp->st_flags = 0; 1596 td->td_retval[0] = n; 1597 return (0); 1598 } 1599 1600 static int 1601 pollout(struct thread *td, struct pollfd *fds, struct pollfd *ufds, u_int nfd) 1602 { 1603 int error = 0; 1604 u_int i = 0; 1605 u_int n = 0; 1606 1607 for (i = 0; i < nfd; i++) { 1608 error = copyout(&fds->revents, &ufds->revents, 1609 sizeof(ufds->revents)); 1610 if (error) 1611 return (error); 1612 if (fds->revents != 0) 1613 n++; 1614 fds++; 1615 ufds++; 1616 } 1617 td->td_retval[0] = n; 1618 return (0); 1619 } 1620 1621 static int 1622 pollscan(struct thread *td, struct pollfd *fds, u_int nfd) 1623 { 1624 struct filedesc *fdp; 1625 struct file *fp; 1626 int i, n, error; 1627 bool only_user; 1628 1629 n = 0; 1630 fdp = td->td_proc->p_fd; 1631 only_user = FILEDESC_IS_ONLY_USER(fdp); 1632 for (i = 0; i < nfd; i++, fds++) { 1633 if (fds->fd < 0) { 1634 fds->revents = 0; 1635 continue; 1636 } 1637 if (only_user) 1638 error = fget_only_user(fdp, fds->fd, &cap_event_rights, &fp); 1639 else 1640 error = fget_unlocked(fdp, fds->fd, &cap_event_rights, &fp); 1641 if (__predict_false(error != 0)) { 1642 fds->revents = POLLNVAL; 1643 n++; 1644 continue; 1645 } 1646 /* 1647 * Note: backend also returns POLLHUP and 1648 * POLLERR if appropriate. 1649 */ 1650 selfdalloc(td, fds); 1651 fds->revents = fo_poll(fp, fds->events, 1652 td->td_ucred, td); 1653 if (only_user) 1654 fput_only_user(fdp, fp); 1655 else 1656 fdrop(fp, td); 1657 /* 1658 * POSIX requires POLLOUT to be never 1659 * set simultaneously with POLLHUP. 1660 */ 1661 if ((fds->revents & POLLHUP) != 0) 1662 fds->revents &= ~POLLOUT; 1663 1664 if (fds->revents != 0) 1665 n++; 1666 } 1667 td->td_retval[0] = n; 1668 return (0); 1669 } 1670 1671 /* 1672 * XXX This was created specifically to support netncp and netsmb. This 1673 * allows the caller to specify a socket to wait for events on. It returns 1674 * 0 if any events matched and an error otherwise. There is no way to 1675 * determine which events fired. 1676 */ 1677 int 1678 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td) 1679 { 1680 struct timeval rtv; 1681 sbintime_t asbt, precision, rsbt; 1682 int error; 1683 1684 precision = 0; /* stupid gcc! */ 1685 if (tvp != NULL) { 1686 rtv = *tvp; 1687 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 || 1688 rtv.tv_usec >= 1000000) 1689 return (EINVAL); 1690 if (!timevalisset(&rtv)) 1691 asbt = 0; 1692 else if (rtv.tv_sec <= INT32_MAX) { 1693 rsbt = tvtosbt(rtv); 1694 precision = rsbt; 1695 precision >>= tc_precexp; 1696 if (TIMESEL(&asbt, rsbt)) 1697 asbt += tc_tick_sbt; 1698 if (asbt <= SBT_MAX - rsbt) 1699 asbt += rsbt; 1700 else 1701 asbt = -1; 1702 } else 1703 asbt = -1; 1704 } else 1705 asbt = -1; 1706 seltdinit(td); 1707 /* 1708 * Iterate until the timeout expires or the socket becomes ready. 1709 */ 1710 for (;;) { 1711 selfdalloc(td, NULL); 1712 error = sopoll(so, events, NULL, td); 1713 /* error here is actually the ready events. */ 1714 if (error) 1715 return (0); 1716 error = seltdwait(td, asbt, precision); 1717 if (error) 1718 break; 1719 } 1720 seltdclear(td); 1721 /* XXX Duplicates ncp/smb behavior. */ 1722 if (error == ERESTART) 1723 error = 0; 1724 return (error); 1725 } 1726 1727 /* 1728 * Preallocate two selfds associated with 'cookie'. Some fo_poll routines 1729 * have two select sets, one for read and another for write. 1730 */ 1731 static void 1732 selfdalloc(struct thread *td, void *cookie) 1733 { 1734 struct seltd *stp; 1735 1736 stp = td->td_sel; 1737 if (stp->st_free1 == NULL) 1738 stp->st_free1 = malloc(sizeof(*stp->st_free1), M_SELFD, M_WAITOK|M_ZERO); 1739 stp->st_free1->sf_td = stp; 1740 stp->st_free1->sf_cookie = cookie; 1741 if (stp->st_free2 == NULL) 1742 stp->st_free2 = malloc(sizeof(*stp->st_free2), M_SELFD, M_WAITOK|M_ZERO); 1743 stp->st_free2->sf_td = stp; 1744 stp->st_free2->sf_cookie = cookie; 1745 } 1746 1747 static void 1748 selfdfree(struct seltd *stp, struct selfd *sfp) 1749 { 1750 STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link); 1751 /* 1752 * Paired with doselwakeup. 1753 */ 1754 if (atomic_load_acq_ptr((uintptr_t *)&sfp->sf_si) != (uintptr_t)NULL) { 1755 mtx_lock(sfp->sf_mtx); 1756 if (sfp->sf_si != NULL) { 1757 TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads); 1758 } 1759 mtx_unlock(sfp->sf_mtx); 1760 } 1761 free(sfp, M_SELFD); 1762 } 1763 1764 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */ 1765 void 1766 seldrain(struct selinfo *sip) 1767 { 1768 1769 /* 1770 * This feature is already provided by doselwakeup(), thus it is 1771 * enough to go for it. 1772 * Eventually, the context, should take care to avoid races 1773 * between thread calling select()/poll() and file descriptor 1774 * detaching, but, again, the races are just the same as 1775 * selwakeup(). 1776 */ 1777 doselwakeup(sip, -1); 1778 } 1779 1780 /* 1781 * Record a select request. 1782 */ 1783 void 1784 selrecord(struct thread *selector, struct selinfo *sip) 1785 { 1786 struct selfd *sfp; 1787 struct seltd *stp; 1788 struct mtx *mtxp; 1789 1790 stp = selector->td_sel; 1791 /* 1792 * Don't record when doing a rescan. 1793 */ 1794 if (stp->st_flags & SELTD_RESCAN) 1795 return; 1796 /* 1797 * Grab one of the preallocated descriptors. 1798 */ 1799 sfp = NULL; 1800 if ((sfp = stp->st_free1) != NULL) 1801 stp->st_free1 = NULL; 1802 else if ((sfp = stp->st_free2) != NULL) 1803 stp->st_free2 = NULL; 1804 else 1805 panic("selrecord: No free selfd on selq"); 1806 mtxp = sip->si_mtx; 1807 if (mtxp == NULL) 1808 mtxp = mtx_pool_find(mtxpool_select, sip); 1809 /* 1810 * Initialize the sfp and queue it in the thread. 1811 */ 1812 sfp->sf_si = sip; 1813 sfp->sf_mtx = mtxp; 1814 STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link); 1815 /* 1816 * Now that we've locked the sip, check for initialization. 1817 */ 1818 mtx_lock(mtxp); 1819 if (sip->si_mtx == NULL) { 1820 sip->si_mtx = mtxp; 1821 TAILQ_INIT(&sip->si_tdlist); 1822 } 1823 /* 1824 * Add this thread to the list of selfds listening on this selinfo. 1825 */ 1826 TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads); 1827 mtx_unlock(sip->si_mtx); 1828 } 1829 1830 /* Wake up a selecting thread. */ 1831 void 1832 selwakeup(struct selinfo *sip) 1833 { 1834 doselwakeup(sip, -1); 1835 } 1836 1837 /* Wake up a selecting thread, and set its priority. */ 1838 void 1839 selwakeuppri(struct selinfo *sip, int pri) 1840 { 1841 doselwakeup(sip, pri); 1842 } 1843 1844 /* 1845 * Do a wakeup when a selectable event occurs. 1846 */ 1847 static void 1848 doselwakeup(struct selinfo *sip, int pri) 1849 { 1850 struct selfd *sfp; 1851 struct selfd *sfn; 1852 struct seltd *stp; 1853 1854 /* If it's not initialized there can't be any waiters. */ 1855 if (sip->si_mtx == NULL) 1856 return; 1857 /* 1858 * Locking the selinfo locks all selfds associated with it. 1859 */ 1860 mtx_lock(sip->si_mtx); 1861 TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) { 1862 /* 1863 * Once we remove this sfp from the list and clear the 1864 * sf_si seltdclear will know to ignore this si. 1865 */ 1866 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads); 1867 stp = sfp->sf_td; 1868 mtx_lock(&stp->st_mtx); 1869 stp->st_flags |= SELTD_PENDING; 1870 cv_broadcastpri(&stp->st_wait, pri); 1871 mtx_unlock(&stp->st_mtx); 1872 /* 1873 * Paired with selfdfree. 1874 * 1875 * Storing this only after the wakeup provides an invariant that 1876 * stp is not used after selfdfree returns. 1877 */ 1878 atomic_store_rel_ptr((uintptr_t *)&sfp->sf_si, (uintptr_t)NULL); 1879 } 1880 mtx_unlock(sip->si_mtx); 1881 } 1882 1883 static void 1884 seltdinit(struct thread *td) 1885 { 1886 struct seltd *stp; 1887 1888 stp = td->td_sel; 1889 if (stp != NULL) { 1890 MPASS(stp->st_flags == 0); 1891 MPASS(STAILQ_EMPTY(&stp->st_selq)); 1892 return; 1893 } 1894 stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO); 1895 mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF); 1896 cv_init(&stp->st_wait, "select"); 1897 stp->st_flags = 0; 1898 STAILQ_INIT(&stp->st_selq); 1899 td->td_sel = stp; 1900 } 1901 1902 static int 1903 seltdwait(struct thread *td, sbintime_t sbt, sbintime_t precision) 1904 { 1905 struct seltd *stp; 1906 int error; 1907 1908 stp = td->td_sel; 1909 /* 1910 * An event of interest may occur while we do not hold the seltd 1911 * locked so check the pending flag before we sleep. 1912 */ 1913 mtx_lock(&stp->st_mtx); 1914 /* 1915 * Any further calls to selrecord will be a rescan. 1916 */ 1917 stp->st_flags |= SELTD_RESCAN; 1918 if (stp->st_flags & SELTD_PENDING) { 1919 mtx_unlock(&stp->st_mtx); 1920 return (0); 1921 } 1922 if (sbt == 0) 1923 error = EWOULDBLOCK; 1924 else if (sbt != -1) 1925 error = cv_timedwait_sig_sbt(&stp->st_wait, &stp->st_mtx, 1926 sbt, precision, C_ABSOLUTE); 1927 else 1928 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx); 1929 mtx_unlock(&stp->st_mtx); 1930 1931 return (error); 1932 } 1933 1934 void 1935 seltdfini(struct thread *td) 1936 { 1937 struct seltd *stp; 1938 1939 stp = td->td_sel; 1940 if (stp == NULL) 1941 return; 1942 MPASS(stp->st_flags == 0); 1943 MPASS(STAILQ_EMPTY(&stp->st_selq)); 1944 if (stp->st_free1) 1945 free(stp->st_free1, M_SELFD); 1946 if (stp->st_free2) 1947 free(stp->st_free2, M_SELFD); 1948 td->td_sel = NULL; 1949 cv_destroy(&stp->st_wait); 1950 mtx_destroy(&stp->st_mtx); 1951 free(stp, M_SELECT); 1952 } 1953 1954 /* 1955 * Remove the references to the thread from all of the objects we were 1956 * polling. 1957 */ 1958 static void 1959 seltdclear(struct thread *td) 1960 { 1961 struct seltd *stp; 1962 struct selfd *sfp; 1963 struct selfd *sfn; 1964 1965 stp = td->td_sel; 1966 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) 1967 selfdfree(stp, sfp); 1968 stp->st_flags = 0; 1969 } 1970 1971 static void selectinit(void *); 1972 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL); 1973 static void 1974 selectinit(void *dummy __unused) 1975 { 1976 1977 mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF); 1978 } 1979 1980 /* 1981 * Set up a syscall return value that follows the convention specified for 1982 * posix_* functions. 1983 */ 1984 int 1985 kern_posix_error(struct thread *td, int error) 1986 { 1987 1988 if (error <= 0) 1989 return (error); 1990 td->td_errno = error; 1991 td->td_pflags |= TDP_NERRNO; 1992 td->td_retval[0] = error; 1993 return (0); 1994 }
Cache object: 92738bfd9c8a1bb82f0f6180326df9af
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