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 * Copyright (c) 1982, 1986, 1989, 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 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)sys_generic.c 8.5 (Berkeley) 1/21/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD: releng/9.1/sys/kern/sys_generic.c 237485 2012-06-23 17:39:40Z davide $"); 39 40 #include "opt_capsicum.h" 41 #include "opt_compat.h" 42 #include "opt_ktrace.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/sysproto.h> 47 #include <sys/capability.h> 48 #include <sys/filedesc.h> 49 #include <sys/filio.h> 50 #include <sys/fcntl.h> 51 #include <sys/file.h> 52 #include <sys/proc.h> 53 #include <sys/signalvar.h> 54 #include <sys/socketvar.h> 55 #include <sys/uio.h> 56 #include <sys/kernel.h> 57 #include <sys/ktr.h> 58 #include <sys/limits.h> 59 #include <sys/malloc.h> 60 #include <sys/poll.h> 61 #include <sys/resourcevar.h> 62 #include <sys/selinfo.h> 63 #include <sys/sleepqueue.h> 64 #include <sys/syscallsubr.h> 65 #include <sys/sysctl.h> 66 #include <sys/sysent.h> 67 #include <sys/vnode.h> 68 #include <sys/bio.h> 69 #include <sys/buf.h> 70 #include <sys/condvar.h> 71 #ifdef KTRACE 72 #include <sys/ktrace.h> 73 #endif 74 75 #include <security/audit/audit.h> 76 77 int iosize_max_clamp = 1; 78 SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW, 79 &iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX"); 80 /* 81 * Assert that the return value of read(2) and write(2) syscalls fits 82 * into a register. If not, an architecture will need to provide the 83 * usermode wrappers to reconstruct the result. 84 */ 85 CTASSERT(sizeof(register_t) >= sizeof(size_t)); 86 87 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer"); 88 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer"); 89 MALLOC_DEFINE(M_IOV, "iov", "large iov's"); 90 91 static int pollout(struct thread *, struct pollfd *, struct pollfd *, 92 u_int); 93 static int pollscan(struct thread *, struct pollfd *, u_int); 94 static int pollrescan(struct thread *); 95 static int selscan(struct thread *, fd_mask **, fd_mask **, int); 96 static int selrescan(struct thread *, fd_mask **, fd_mask **); 97 static void selfdalloc(struct thread *, void *); 98 static void selfdfree(struct seltd *, struct selfd *); 99 static int dofileread(struct thread *, int, struct file *, struct uio *, 100 off_t, int); 101 static int dofilewrite(struct thread *, int, struct file *, struct uio *, 102 off_t, int); 103 static void doselwakeup(struct selinfo *, int); 104 static void seltdinit(struct thread *); 105 static int seltdwait(struct thread *, int); 106 static void seltdclear(struct thread *); 107 108 /* 109 * One seltd per-thread allocated on demand as needed. 110 * 111 * t - protected by st_mtx 112 * k - Only accessed by curthread or read-only 113 */ 114 struct seltd { 115 STAILQ_HEAD(, selfd) st_selq; /* (k) List of selfds. */ 116 struct selfd *st_free1; /* (k) free fd for read set. */ 117 struct selfd *st_free2; /* (k) free fd for write set. */ 118 struct mtx st_mtx; /* Protects struct seltd */ 119 struct cv st_wait; /* (t) Wait channel. */ 120 int st_flags; /* (t) SELTD_ flags. */ 121 }; 122 123 #define SELTD_PENDING 0x0001 /* We have pending events. */ 124 #define SELTD_RESCAN 0x0002 /* Doing a rescan. */ 125 126 /* 127 * One selfd allocated per-thread per-file-descriptor. 128 * f - protected by sf_mtx 129 */ 130 struct selfd { 131 STAILQ_ENTRY(selfd) sf_link; /* (k) fds owned by this td. */ 132 TAILQ_ENTRY(selfd) sf_threads; /* (f) fds on this selinfo. */ 133 struct selinfo *sf_si; /* (f) selinfo when linked. */ 134 struct mtx *sf_mtx; /* Pointer to selinfo mtx. */ 135 struct seltd *sf_td; /* (k) owning seltd. */ 136 void *sf_cookie; /* (k) fd or pollfd. */ 137 }; 138 139 static uma_zone_t selfd_zone; 140 static struct mtx_pool *mtxpool_select; 141 142 #ifndef _SYS_SYSPROTO_H_ 143 struct read_args { 144 int fd; 145 void *buf; 146 size_t nbyte; 147 }; 148 #endif 149 int 150 sys_read(td, uap) 151 struct thread *td; 152 struct read_args *uap; 153 { 154 struct uio auio; 155 struct iovec aiov; 156 int error; 157 158 if (uap->nbyte > IOSIZE_MAX) 159 return (EINVAL); 160 aiov.iov_base = uap->buf; 161 aiov.iov_len = uap->nbyte; 162 auio.uio_iov = &aiov; 163 auio.uio_iovcnt = 1; 164 auio.uio_resid = uap->nbyte; 165 auio.uio_segflg = UIO_USERSPACE; 166 error = kern_readv(td, uap->fd, &auio); 167 return(error); 168 } 169 170 /* 171 * Positioned read system call 172 */ 173 #ifndef _SYS_SYSPROTO_H_ 174 struct pread_args { 175 int fd; 176 void *buf; 177 size_t nbyte; 178 int pad; 179 off_t offset; 180 }; 181 #endif 182 int 183 sys_pread(td, uap) 184 struct thread *td; 185 struct pread_args *uap; 186 { 187 struct uio auio; 188 struct iovec aiov; 189 int error; 190 191 if (uap->nbyte > IOSIZE_MAX) 192 return (EINVAL); 193 aiov.iov_base = uap->buf; 194 aiov.iov_len = uap->nbyte; 195 auio.uio_iov = &aiov; 196 auio.uio_iovcnt = 1; 197 auio.uio_resid = uap->nbyte; 198 auio.uio_segflg = UIO_USERSPACE; 199 error = kern_preadv(td, uap->fd, &auio, uap->offset); 200 return(error); 201 } 202 203 int 204 freebsd6_pread(td, uap) 205 struct thread *td; 206 struct freebsd6_pread_args *uap; 207 { 208 struct pread_args oargs; 209 210 oargs.fd = uap->fd; 211 oargs.buf = uap->buf; 212 oargs.nbyte = uap->nbyte; 213 oargs.offset = uap->offset; 214 return (sys_pread(td, &oargs)); 215 } 216 217 /* 218 * Scatter read system call. 219 */ 220 #ifndef _SYS_SYSPROTO_H_ 221 struct readv_args { 222 int fd; 223 struct iovec *iovp; 224 u_int iovcnt; 225 }; 226 #endif 227 int 228 sys_readv(struct thread *td, struct readv_args *uap) 229 { 230 struct uio *auio; 231 int error; 232 233 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 234 if (error) 235 return (error); 236 error = kern_readv(td, uap->fd, auio); 237 free(auio, M_IOV); 238 return (error); 239 } 240 241 int 242 kern_readv(struct thread *td, int fd, struct uio *auio) 243 { 244 struct file *fp; 245 int error; 246 247 error = fget_read(td, fd, CAP_READ | CAP_SEEK, &fp); 248 if (error) 249 return (error); 250 error = dofileread(td, fd, fp, auio, (off_t)-1, 0); 251 fdrop(fp, td); 252 return (error); 253 } 254 255 /* 256 * Scatter positioned read system call. 257 */ 258 #ifndef _SYS_SYSPROTO_H_ 259 struct preadv_args { 260 int fd; 261 struct iovec *iovp; 262 u_int iovcnt; 263 off_t offset; 264 }; 265 #endif 266 int 267 sys_preadv(struct thread *td, struct preadv_args *uap) 268 { 269 struct uio *auio; 270 int error; 271 272 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 273 if (error) 274 return (error); 275 error = kern_preadv(td, uap->fd, auio, uap->offset); 276 free(auio, M_IOV); 277 return (error); 278 } 279 280 int 281 kern_preadv(td, fd, auio, offset) 282 struct thread *td; 283 int fd; 284 struct uio *auio; 285 off_t offset; 286 { 287 struct file *fp; 288 int error; 289 290 error = fget_read(td, fd, CAP_READ, &fp); 291 if (error) 292 return (error); 293 if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE)) 294 error = ESPIPE; 295 else if (offset < 0 && fp->f_vnode->v_type != VCHR) 296 error = EINVAL; 297 else 298 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET); 299 fdrop(fp, td); 300 return (error); 301 } 302 303 /* 304 * Common code for readv and preadv that reads data in 305 * from a file using the passed in uio, offset, and flags. 306 */ 307 static int 308 dofileread(td, fd, fp, auio, offset, flags) 309 struct thread *td; 310 int fd; 311 struct file *fp; 312 struct uio *auio; 313 off_t offset; 314 int flags; 315 { 316 ssize_t cnt; 317 int error; 318 #ifdef KTRACE 319 struct uio *ktruio = NULL; 320 #endif 321 322 /* Finish zero length reads right here */ 323 if (auio->uio_resid == 0) { 324 td->td_retval[0] = 0; 325 return(0); 326 } 327 auio->uio_rw = UIO_READ; 328 auio->uio_offset = offset; 329 auio->uio_td = td; 330 #ifdef KTRACE 331 if (KTRPOINT(td, KTR_GENIO)) 332 ktruio = cloneuio(auio); 333 #endif 334 cnt = auio->uio_resid; 335 if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) { 336 if (auio->uio_resid != cnt && (error == ERESTART || 337 error == EINTR || error == EWOULDBLOCK)) 338 error = 0; 339 } 340 cnt -= auio->uio_resid; 341 #ifdef KTRACE 342 if (ktruio != NULL) { 343 ktruio->uio_resid = cnt; 344 ktrgenio(fd, UIO_READ, ktruio, error); 345 } 346 #endif 347 td->td_retval[0] = cnt; 348 return (error); 349 } 350 351 #ifndef _SYS_SYSPROTO_H_ 352 struct write_args { 353 int fd; 354 const void *buf; 355 size_t nbyte; 356 }; 357 #endif 358 int 359 sys_write(td, uap) 360 struct thread *td; 361 struct write_args *uap; 362 { 363 struct uio auio; 364 struct iovec aiov; 365 int error; 366 367 if (uap->nbyte > IOSIZE_MAX) 368 return (EINVAL); 369 aiov.iov_base = (void *)(uintptr_t)uap->buf; 370 aiov.iov_len = uap->nbyte; 371 auio.uio_iov = &aiov; 372 auio.uio_iovcnt = 1; 373 auio.uio_resid = uap->nbyte; 374 auio.uio_segflg = UIO_USERSPACE; 375 error = kern_writev(td, uap->fd, &auio); 376 return(error); 377 } 378 379 /* 380 * Positioned write system call. 381 */ 382 #ifndef _SYS_SYSPROTO_H_ 383 struct pwrite_args { 384 int fd; 385 const void *buf; 386 size_t nbyte; 387 int pad; 388 off_t offset; 389 }; 390 #endif 391 int 392 sys_pwrite(td, uap) 393 struct thread *td; 394 struct pwrite_args *uap; 395 { 396 struct uio auio; 397 struct iovec aiov; 398 int error; 399 400 if (uap->nbyte > IOSIZE_MAX) 401 return (EINVAL); 402 aiov.iov_base = (void *)(uintptr_t)uap->buf; 403 aiov.iov_len = uap->nbyte; 404 auio.uio_iov = &aiov; 405 auio.uio_iovcnt = 1; 406 auio.uio_resid = uap->nbyte; 407 auio.uio_segflg = UIO_USERSPACE; 408 error = kern_pwritev(td, uap->fd, &auio, uap->offset); 409 return(error); 410 } 411 412 int 413 freebsd6_pwrite(td, uap) 414 struct thread *td; 415 struct freebsd6_pwrite_args *uap; 416 { 417 struct pwrite_args oargs; 418 419 oargs.fd = uap->fd; 420 oargs.buf = uap->buf; 421 oargs.nbyte = uap->nbyte; 422 oargs.offset = uap->offset; 423 return (sys_pwrite(td, &oargs)); 424 } 425 426 /* 427 * Gather write system call. 428 */ 429 #ifndef _SYS_SYSPROTO_H_ 430 struct writev_args { 431 int fd; 432 struct iovec *iovp; 433 u_int iovcnt; 434 }; 435 #endif 436 int 437 sys_writev(struct thread *td, struct writev_args *uap) 438 { 439 struct uio *auio; 440 int error; 441 442 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 443 if (error) 444 return (error); 445 error = kern_writev(td, uap->fd, auio); 446 free(auio, M_IOV); 447 return (error); 448 } 449 450 int 451 kern_writev(struct thread *td, int fd, struct uio *auio) 452 { 453 struct file *fp; 454 int error; 455 456 error = fget_write(td, fd, CAP_WRITE | CAP_SEEK, &fp); 457 if (error) 458 return (error); 459 error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0); 460 fdrop(fp, td); 461 return (error); 462 } 463 464 /* 465 * Gather positioned write system call. 466 */ 467 #ifndef _SYS_SYSPROTO_H_ 468 struct pwritev_args { 469 int fd; 470 struct iovec *iovp; 471 u_int iovcnt; 472 off_t offset; 473 }; 474 #endif 475 int 476 sys_pwritev(struct thread *td, struct pwritev_args *uap) 477 { 478 struct uio *auio; 479 int error; 480 481 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 482 if (error) 483 return (error); 484 error = kern_pwritev(td, uap->fd, auio, uap->offset); 485 free(auio, M_IOV); 486 return (error); 487 } 488 489 int 490 kern_pwritev(td, fd, auio, offset) 491 struct thread *td; 492 struct uio *auio; 493 int fd; 494 off_t offset; 495 { 496 struct file *fp; 497 int error; 498 499 error = fget_write(td, fd, CAP_WRITE, &fp); 500 if (error) 501 return (error); 502 if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE)) 503 error = ESPIPE; 504 else if (offset < 0 && fp->f_vnode->v_type != VCHR) 505 error = EINVAL; 506 else 507 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET); 508 fdrop(fp, td); 509 return (error); 510 } 511 512 /* 513 * Common code for writev and pwritev that writes data to 514 * a file using the passed in uio, offset, and flags. 515 */ 516 static int 517 dofilewrite(td, fd, fp, auio, offset, flags) 518 struct thread *td; 519 int fd; 520 struct file *fp; 521 struct uio *auio; 522 off_t offset; 523 int flags; 524 { 525 ssize_t cnt; 526 int error; 527 #ifdef KTRACE 528 struct uio *ktruio = NULL; 529 #endif 530 531 auio->uio_rw = UIO_WRITE; 532 auio->uio_td = td; 533 auio->uio_offset = offset; 534 #ifdef KTRACE 535 if (KTRPOINT(td, KTR_GENIO)) 536 ktruio = cloneuio(auio); 537 #endif 538 cnt = auio->uio_resid; 539 if (fp->f_type == DTYPE_VNODE) 540 bwillwrite(); 541 if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) { 542 if (auio->uio_resid != cnt && (error == ERESTART || 543 error == EINTR || error == EWOULDBLOCK)) 544 error = 0; 545 /* Socket layer is responsible for issuing SIGPIPE. */ 546 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) { 547 PROC_LOCK(td->td_proc); 548 tdsignal(td, SIGPIPE); 549 PROC_UNLOCK(td->td_proc); 550 } 551 } 552 cnt -= auio->uio_resid; 553 #ifdef KTRACE 554 if (ktruio != NULL) { 555 ktruio->uio_resid = cnt; 556 ktrgenio(fd, UIO_WRITE, ktruio, error); 557 } 558 #endif 559 td->td_retval[0] = cnt; 560 return (error); 561 } 562 563 /* 564 * Truncate a file given a file descriptor. 565 * 566 * Can't use fget_write() here, since must return EINVAL and not EBADF if the 567 * descriptor isn't writable. 568 */ 569 int 570 kern_ftruncate(td, fd, length) 571 struct thread *td; 572 int fd; 573 off_t length; 574 { 575 struct file *fp; 576 int error; 577 578 AUDIT_ARG_FD(fd); 579 if (length < 0) 580 return (EINVAL); 581 error = fget(td, fd, CAP_FTRUNCATE, &fp); 582 if (error) 583 return (error); 584 AUDIT_ARG_FILE(td->td_proc, fp); 585 if (!(fp->f_flag & FWRITE)) { 586 fdrop(fp, td); 587 return (EINVAL); 588 } 589 error = fo_truncate(fp, length, td->td_ucred, td); 590 fdrop(fp, td); 591 return (error); 592 } 593 594 #ifndef _SYS_SYSPROTO_H_ 595 struct ftruncate_args { 596 int fd; 597 int pad; 598 off_t length; 599 }; 600 #endif 601 int 602 sys_ftruncate(td, uap) 603 struct thread *td; 604 struct ftruncate_args *uap; 605 { 606 607 return (kern_ftruncate(td, uap->fd, uap->length)); 608 } 609 610 #if defined(COMPAT_43) 611 #ifndef _SYS_SYSPROTO_H_ 612 struct oftruncate_args { 613 int fd; 614 long length; 615 }; 616 #endif 617 int 618 oftruncate(td, uap) 619 struct thread *td; 620 struct oftruncate_args *uap; 621 { 622 623 return (kern_ftruncate(td, uap->fd, uap->length)); 624 } 625 #endif /* COMPAT_43 */ 626 627 #ifndef _SYS_SYSPROTO_H_ 628 struct ioctl_args { 629 int fd; 630 u_long com; 631 caddr_t data; 632 }; 633 #endif 634 /* ARGSUSED */ 635 int 636 sys_ioctl(struct thread *td, struct ioctl_args *uap) 637 { 638 u_long com; 639 int arg, error; 640 u_int size; 641 caddr_t data; 642 643 if (uap->com > 0xffffffff) { 644 printf( 645 "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n", 646 td->td_proc->p_pid, td->td_name, uap->com); 647 uap->com &= 0xffffffff; 648 } 649 com = uap->com; 650 651 /* 652 * Interpret high order word to find amount of data to be 653 * copied to/from the user's address space. 654 */ 655 size = IOCPARM_LEN(com); 656 if ((size > IOCPARM_MAX) || 657 ((com & (IOC_VOID | IOC_IN | IOC_OUT)) == 0) || 658 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43) 659 ((com & IOC_OUT) && size == 0) || 660 #else 661 ((com & (IOC_IN | IOC_OUT)) && size == 0) || 662 #endif 663 ((com & IOC_VOID) && size > 0 && size != sizeof(int))) 664 return (ENOTTY); 665 666 if (size > 0) { 667 if (com & IOC_VOID) { 668 /* Integer argument. */ 669 arg = (intptr_t)uap->data; 670 data = (void *)&arg; 671 size = 0; 672 } else 673 data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK); 674 } else 675 data = (void *)&uap->data; 676 if (com & IOC_IN) { 677 error = copyin(uap->data, data, (u_int)size); 678 if (error) { 679 if (size > 0) 680 free(data, M_IOCTLOPS); 681 return (error); 682 } 683 } else if (com & IOC_OUT) { 684 /* 685 * Zero the buffer so the user always 686 * gets back something deterministic. 687 */ 688 bzero(data, size); 689 } 690 691 error = kern_ioctl(td, uap->fd, com, data); 692 693 if (error == 0 && (com & IOC_OUT)) 694 error = copyout(data, uap->data, (u_int)size); 695 696 if (size > 0) 697 free(data, M_IOCTLOPS); 698 return (error); 699 } 700 701 int 702 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data) 703 { 704 struct file *fp; 705 struct filedesc *fdp; 706 int error; 707 int tmp; 708 709 AUDIT_ARG_FD(fd); 710 AUDIT_ARG_CMD(com); 711 if ((error = fget(td, fd, CAP_IOCTL, &fp)) != 0) 712 return (error); 713 if ((fp->f_flag & (FREAD | FWRITE)) == 0) { 714 fdrop(fp, td); 715 return (EBADF); 716 } 717 fdp = td->td_proc->p_fd; 718 switch (com) { 719 case FIONCLEX: 720 FILEDESC_XLOCK(fdp); 721 fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE; 722 FILEDESC_XUNLOCK(fdp); 723 goto out; 724 case FIOCLEX: 725 FILEDESC_XLOCK(fdp); 726 fdp->fd_ofileflags[fd] |= UF_EXCLOSE; 727 FILEDESC_XUNLOCK(fdp); 728 goto out; 729 case FIONBIO: 730 if ((tmp = *(int *)data)) 731 atomic_set_int(&fp->f_flag, FNONBLOCK); 732 else 733 atomic_clear_int(&fp->f_flag, FNONBLOCK); 734 data = (void *)&tmp; 735 break; 736 case FIOASYNC: 737 if ((tmp = *(int *)data)) 738 atomic_set_int(&fp->f_flag, FASYNC); 739 else 740 atomic_clear_int(&fp->f_flag, FASYNC); 741 data = (void *)&tmp; 742 break; 743 } 744 745 error = fo_ioctl(fp, com, data, td->td_ucred, td); 746 out: 747 fdrop(fp, td); 748 return (error); 749 } 750 751 int 752 poll_no_poll(int events) 753 { 754 /* 755 * Return true for read/write. If the user asked for something 756 * special, return POLLNVAL, so that clients have a way of 757 * determining reliably whether or not the extended 758 * functionality is present without hard-coding knowledge 759 * of specific filesystem implementations. 760 */ 761 if (events & ~POLLSTANDARD) 762 return (POLLNVAL); 763 764 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 765 } 766 767 int 768 sys_pselect(struct thread *td, struct pselect_args *uap) 769 { 770 struct timespec ts; 771 struct timeval tv, *tvp; 772 sigset_t set, *uset; 773 int error; 774 775 if (uap->ts != NULL) { 776 error = copyin(uap->ts, &ts, sizeof(ts)); 777 if (error != 0) 778 return (error); 779 TIMESPEC_TO_TIMEVAL(&tv, &ts); 780 tvp = &tv; 781 } else 782 tvp = NULL; 783 if (uap->sm != NULL) { 784 error = copyin(uap->sm, &set, sizeof(set)); 785 if (error != 0) 786 return (error); 787 uset = &set; 788 } else 789 uset = NULL; 790 return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp, 791 uset, NFDBITS)); 792 } 793 794 int 795 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex, 796 struct timeval *tvp, sigset_t *uset, int abi_nfdbits) 797 { 798 int error; 799 800 if (uset != NULL) { 801 error = kern_sigprocmask(td, SIG_SETMASK, uset, 802 &td->td_oldsigmask, 0); 803 if (error != 0) 804 return (error); 805 td->td_pflags |= TDP_OLDMASK; 806 /* 807 * Make sure that ast() is called on return to 808 * usermode and TDP_OLDMASK is cleared, restoring old 809 * sigmask. 810 */ 811 thread_lock(td); 812 td->td_flags |= TDF_ASTPENDING; 813 thread_unlock(td); 814 } 815 error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits); 816 return (error); 817 } 818 819 #ifndef _SYS_SYSPROTO_H_ 820 struct select_args { 821 int nd; 822 fd_set *in, *ou, *ex; 823 struct timeval *tv; 824 }; 825 #endif 826 int 827 sys_select(struct thread *td, struct select_args *uap) 828 { 829 struct timeval tv, *tvp; 830 int error; 831 832 if (uap->tv != NULL) { 833 error = copyin(uap->tv, &tv, sizeof(tv)); 834 if (error) 835 return (error); 836 tvp = &tv; 837 } else 838 tvp = NULL; 839 840 return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp, 841 NFDBITS)); 842 } 843 844 /* 845 * In the unlikely case when user specified n greater then the last 846 * open file descriptor, check that no bits are set after the last 847 * valid fd. We must return EBADF if any is set. 848 * 849 * There are applications that rely on the behaviour. 850 * 851 * nd is fd_lastfile + 1. 852 */ 853 static int 854 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits) 855 { 856 char *addr, *oaddr; 857 int b, i, res; 858 uint8_t bits; 859 860 if (nd >= ndu || fd_in == NULL) 861 return (0); 862 863 oaddr = NULL; 864 bits = 0; /* silence gcc */ 865 for (i = nd; i < ndu; i++) { 866 b = i / NBBY; 867 #if BYTE_ORDER == LITTLE_ENDIAN 868 addr = (char *)fd_in + b; 869 #else 870 addr = (char *)fd_in; 871 if (abi_nfdbits == NFDBITS) { 872 addr += rounddown(b, sizeof(fd_mask)) + 873 sizeof(fd_mask) - 1 - b % sizeof(fd_mask); 874 } else { 875 addr += rounddown(b, sizeof(uint32_t)) + 876 sizeof(uint32_t) - 1 - b % sizeof(uint32_t); 877 } 878 #endif 879 if (addr != oaddr) { 880 res = fubyte(addr); 881 if (res == -1) 882 return (EFAULT); 883 oaddr = addr; 884 bits = res; 885 } 886 if ((bits & (1 << (i % NBBY))) != 0) 887 return (EBADF); 888 } 889 return (0); 890 } 891 892 int 893 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou, 894 fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits) 895 { 896 struct filedesc *fdp; 897 /* 898 * The magic 2048 here is chosen to be just enough for FD_SETSIZE 899 * infds with the new FD_SETSIZE of 1024, and more than enough for 900 * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE 901 * of 256. 902 */ 903 fd_mask s_selbits[howmany(2048, NFDBITS)]; 904 fd_mask *ibits[3], *obits[3], *selbits, *sbp; 905 struct timeval atv, rtv, ttv; 906 int error, lf, ndu, timo; 907 u_int nbufbytes, ncpbytes, ncpubytes, nfdbits; 908 909 if (nd < 0) 910 return (EINVAL); 911 fdp = td->td_proc->p_fd; 912 ndu = nd; 913 lf = fdp->fd_lastfile; 914 if (nd > lf + 1) 915 nd = lf + 1; 916 917 error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits); 918 if (error != 0) 919 return (error); 920 error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits); 921 if (error != 0) 922 return (error); 923 error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits); 924 if (error != 0) 925 return (error); 926 927 /* 928 * Allocate just enough bits for the non-null fd_sets. Use the 929 * preallocated auto buffer if possible. 930 */ 931 nfdbits = roundup(nd, NFDBITS); 932 ncpbytes = nfdbits / NBBY; 933 ncpubytes = roundup(nd, abi_nfdbits) / NBBY; 934 nbufbytes = 0; 935 if (fd_in != NULL) 936 nbufbytes += 2 * ncpbytes; 937 if (fd_ou != NULL) 938 nbufbytes += 2 * ncpbytes; 939 if (fd_ex != NULL) 940 nbufbytes += 2 * ncpbytes; 941 if (nbufbytes <= sizeof s_selbits) 942 selbits = &s_selbits[0]; 943 else 944 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK); 945 946 /* 947 * Assign pointers into the bit buffers and fetch the input bits. 948 * Put the output buffers together so that they can be bzeroed 949 * together. 950 */ 951 sbp = selbits; 952 #define getbits(name, x) \ 953 do { \ 954 if (name == NULL) { \ 955 ibits[x] = NULL; \ 956 obits[x] = NULL; \ 957 } else { \ 958 ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp; \ 959 obits[x] = sbp; \ 960 sbp += ncpbytes / sizeof *sbp; \ 961 error = copyin(name, ibits[x], ncpubytes); \ 962 if (error != 0) \ 963 goto done; \ 964 bzero((char *)ibits[x] + ncpubytes, \ 965 ncpbytes - ncpubytes); \ 966 } \ 967 } while (0) 968 getbits(fd_in, 0); 969 getbits(fd_ou, 1); 970 getbits(fd_ex, 2); 971 #undef getbits 972 973 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__) 974 /* 975 * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS, 976 * we are running under 32-bit emulation. This should be more 977 * generic. 978 */ 979 #define swizzle_fdset(bits) \ 980 if (abi_nfdbits != NFDBITS && bits != NULL) { \ 981 int i; \ 982 for (i = 0; i < ncpbytes / sizeof *sbp; i++) \ 983 bits[i] = (bits[i] >> 32) | (bits[i] << 32); \ 984 } 985 #else 986 #define swizzle_fdset(bits) 987 #endif 988 989 /* Make sure the bit order makes it through an ABI transition */ 990 swizzle_fdset(ibits[0]); 991 swizzle_fdset(ibits[1]); 992 swizzle_fdset(ibits[2]); 993 994 if (nbufbytes != 0) 995 bzero(selbits, nbufbytes / 2); 996 997 if (tvp != NULL) { 998 atv = *tvp; 999 if (itimerfix(&atv)) { 1000 error = EINVAL; 1001 goto done; 1002 } 1003 getmicrouptime(&rtv); 1004 timevaladd(&atv, &rtv); 1005 } else { 1006 atv.tv_sec = 0; 1007 atv.tv_usec = 0; 1008 } 1009 timo = 0; 1010 seltdinit(td); 1011 /* Iterate until the timeout expires or descriptors become ready. */ 1012 for (;;) { 1013 error = selscan(td, ibits, obits, nd); 1014 if (error || td->td_retval[0] != 0) 1015 break; 1016 if (atv.tv_sec || atv.tv_usec) { 1017 getmicrouptime(&rtv); 1018 if (timevalcmp(&rtv, &atv, >=)) 1019 break; 1020 ttv = atv; 1021 timevalsub(&ttv, &rtv); 1022 timo = ttv.tv_sec > 24 * 60 * 60 ? 1023 24 * 60 * 60 * hz : tvtohz(&ttv); 1024 } 1025 error = seltdwait(td, timo); 1026 if (error) 1027 break; 1028 error = selrescan(td, ibits, obits); 1029 if (error || td->td_retval[0] != 0) 1030 break; 1031 } 1032 seltdclear(td); 1033 1034 done: 1035 /* select is not restarted after signals... */ 1036 if (error == ERESTART) 1037 error = EINTR; 1038 if (error == EWOULDBLOCK) 1039 error = 0; 1040 1041 /* swizzle bit order back, if necessary */ 1042 swizzle_fdset(obits[0]); 1043 swizzle_fdset(obits[1]); 1044 swizzle_fdset(obits[2]); 1045 #undef swizzle_fdset 1046 1047 #define putbits(name, x) \ 1048 if (name && (error2 = copyout(obits[x], name, ncpubytes))) \ 1049 error = error2; 1050 if (error == 0) { 1051 int error2; 1052 1053 putbits(fd_in, 0); 1054 putbits(fd_ou, 1); 1055 putbits(fd_ex, 2); 1056 #undef putbits 1057 } 1058 if (selbits != &s_selbits[0]) 1059 free(selbits, M_SELECT); 1060 1061 return (error); 1062 } 1063 /* 1064 * Convert a select bit set to poll flags. 1065 * 1066 * The backend always returns POLLHUP/POLLERR if appropriate and we 1067 * return this as a set bit in any set. 1068 */ 1069 static int select_flags[3] = { 1070 POLLRDNORM | POLLHUP | POLLERR, 1071 POLLWRNORM | POLLHUP | POLLERR, 1072 POLLRDBAND | POLLERR 1073 }; 1074 1075 /* 1076 * Compute the fo_poll flags required for a fd given by the index and 1077 * bit position in the fd_mask array. 1078 */ 1079 static __inline int 1080 selflags(fd_mask **ibits, int idx, fd_mask bit) 1081 { 1082 int flags; 1083 int msk; 1084 1085 flags = 0; 1086 for (msk = 0; msk < 3; msk++) { 1087 if (ibits[msk] == NULL) 1088 continue; 1089 if ((ibits[msk][idx] & bit) == 0) 1090 continue; 1091 flags |= select_flags[msk]; 1092 } 1093 return (flags); 1094 } 1095 1096 /* 1097 * Set the appropriate output bits given a mask of fired events and the 1098 * input bits originally requested. 1099 */ 1100 static __inline int 1101 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events) 1102 { 1103 int msk; 1104 int n; 1105 1106 n = 0; 1107 for (msk = 0; msk < 3; msk++) { 1108 if ((events & select_flags[msk]) == 0) 1109 continue; 1110 if (ibits[msk] == NULL) 1111 continue; 1112 if ((ibits[msk][idx] & bit) == 0) 1113 continue; 1114 /* 1115 * XXX Check for a duplicate set. This can occur because a 1116 * socket calls selrecord() twice for each poll() call 1117 * resulting in two selfds per real fd. selrescan() will 1118 * call selsetbits twice as a result. 1119 */ 1120 if ((obits[msk][idx] & bit) != 0) 1121 continue; 1122 obits[msk][idx] |= bit; 1123 n++; 1124 } 1125 1126 return (n); 1127 } 1128 1129 static __inline int 1130 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp) 1131 { 1132 struct file *fp; 1133 #ifdef CAPABILITIES 1134 struct file *fp_fromcap; 1135 int error; 1136 #endif 1137 1138 if ((fp = fget_unlocked(fdp, fd)) == NULL) 1139 return (EBADF); 1140 #ifdef CAPABILITIES 1141 /* 1142 * If the file descriptor is for a capability, test rights and use 1143 * the file descriptor references by the capability. 1144 */ 1145 error = cap_funwrap(fp, CAP_POLL_EVENT, &fp_fromcap); 1146 if (error) { 1147 fdrop(fp, curthread); 1148 return (error); 1149 } 1150 if (fp != fp_fromcap) { 1151 fhold(fp_fromcap); 1152 fdrop(fp, curthread); 1153 fp = fp_fromcap; 1154 } 1155 #endif /* CAPABILITIES */ 1156 *fpp = fp; 1157 return (0); 1158 } 1159 1160 /* 1161 * Traverse the list of fds attached to this thread's seltd and check for 1162 * completion. 1163 */ 1164 static int 1165 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits) 1166 { 1167 struct filedesc *fdp; 1168 struct selinfo *si; 1169 struct seltd *stp; 1170 struct selfd *sfp; 1171 struct selfd *sfn; 1172 struct file *fp; 1173 fd_mask bit; 1174 int fd, ev, n, idx; 1175 int error; 1176 1177 fdp = td->td_proc->p_fd; 1178 stp = td->td_sel; 1179 n = 0; 1180 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) { 1181 fd = (int)(uintptr_t)sfp->sf_cookie; 1182 si = sfp->sf_si; 1183 selfdfree(stp, sfp); 1184 /* If the selinfo wasn't cleared the event didn't fire. */ 1185 if (si != NULL) 1186 continue; 1187 error = getselfd_cap(fdp, fd, &fp); 1188 if (error) 1189 return (error); 1190 idx = fd / NFDBITS; 1191 bit = (fd_mask)1 << (fd % NFDBITS); 1192 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td); 1193 fdrop(fp, td); 1194 if (ev != 0) 1195 n += selsetbits(ibits, obits, idx, bit, ev); 1196 } 1197 stp->st_flags = 0; 1198 td->td_retval[0] = n; 1199 return (0); 1200 } 1201 1202 /* 1203 * Perform the initial filedescriptor scan and register ourselves with 1204 * each selinfo. 1205 */ 1206 static int 1207 selscan(td, ibits, obits, nfd) 1208 struct thread *td; 1209 fd_mask **ibits, **obits; 1210 int nfd; 1211 { 1212 struct filedesc *fdp; 1213 struct file *fp; 1214 fd_mask bit; 1215 int ev, flags, end, fd; 1216 int n, idx; 1217 int error; 1218 1219 fdp = td->td_proc->p_fd; 1220 n = 0; 1221 for (idx = 0, fd = 0; fd < nfd; idx++) { 1222 end = imin(fd + NFDBITS, nfd); 1223 for (bit = 1; fd < end; bit <<= 1, fd++) { 1224 /* Compute the list of events we're interested in. */ 1225 flags = selflags(ibits, idx, bit); 1226 if (flags == 0) 1227 continue; 1228 error = getselfd_cap(fdp, fd, &fp); 1229 if (error) 1230 return (error); 1231 selfdalloc(td, (void *)(uintptr_t)fd); 1232 ev = fo_poll(fp, flags, td->td_ucred, td); 1233 fdrop(fp, td); 1234 if (ev != 0) 1235 n += selsetbits(ibits, obits, idx, bit, ev); 1236 } 1237 } 1238 1239 td->td_retval[0] = n; 1240 return (0); 1241 } 1242 1243 #ifndef _SYS_SYSPROTO_H_ 1244 struct poll_args { 1245 struct pollfd *fds; 1246 u_int nfds; 1247 int timeout; 1248 }; 1249 #endif 1250 int 1251 sys_poll(td, uap) 1252 struct thread *td; 1253 struct poll_args *uap; 1254 { 1255 struct pollfd *bits; 1256 struct pollfd smallbits[32]; 1257 struct timeval atv, rtv, ttv; 1258 int error, timo; 1259 u_int nfds; 1260 size_t ni; 1261 1262 nfds = uap->nfds; 1263 if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 1264 return (EINVAL); 1265 ni = nfds * sizeof(struct pollfd); 1266 if (ni > sizeof(smallbits)) 1267 bits = malloc(ni, M_TEMP, M_WAITOK); 1268 else 1269 bits = smallbits; 1270 error = copyin(uap->fds, bits, ni); 1271 if (error) 1272 goto done; 1273 if (uap->timeout != INFTIM) { 1274 atv.tv_sec = uap->timeout / 1000; 1275 atv.tv_usec = (uap->timeout % 1000) * 1000; 1276 if (itimerfix(&atv)) { 1277 error = EINVAL; 1278 goto done; 1279 } 1280 getmicrouptime(&rtv); 1281 timevaladd(&atv, &rtv); 1282 } else { 1283 atv.tv_sec = 0; 1284 atv.tv_usec = 0; 1285 } 1286 timo = 0; 1287 seltdinit(td); 1288 /* Iterate until the timeout expires or descriptors become ready. */ 1289 for (;;) { 1290 error = pollscan(td, bits, nfds); 1291 if (error || td->td_retval[0] != 0) 1292 break; 1293 if (atv.tv_sec || atv.tv_usec) { 1294 getmicrouptime(&rtv); 1295 if (timevalcmp(&rtv, &atv, >=)) 1296 break; 1297 ttv = atv; 1298 timevalsub(&ttv, &rtv); 1299 timo = ttv.tv_sec > 24 * 60 * 60 ? 1300 24 * 60 * 60 * hz : tvtohz(&ttv); 1301 } 1302 error = seltdwait(td, timo); 1303 if (error) 1304 break; 1305 error = pollrescan(td); 1306 if (error || td->td_retval[0] != 0) 1307 break; 1308 } 1309 seltdclear(td); 1310 1311 done: 1312 /* poll is not restarted after signals... */ 1313 if (error == ERESTART) 1314 error = EINTR; 1315 if (error == EWOULDBLOCK) 1316 error = 0; 1317 if (error == 0) { 1318 error = pollout(td, bits, uap->fds, nfds); 1319 if (error) 1320 goto out; 1321 } 1322 out: 1323 if (ni > sizeof(smallbits)) 1324 free(bits, M_TEMP); 1325 return (error); 1326 } 1327 1328 static int 1329 pollrescan(struct thread *td) 1330 { 1331 struct seltd *stp; 1332 struct selfd *sfp; 1333 struct selfd *sfn; 1334 struct selinfo *si; 1335 struct filedesc *fdp; 1336 struct file *fp; 1337 struct pollfd *fd; 1338 int n; 1339 1340 n = 0; 1341 fdp = td->td_proc->p_fd; 1342 stp = td->td_sel; 1343 FILEDESC_SLOCK(fdp); 1344 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) { 1345 fd = (struct pollfd *)sfp->sf_cookie; 1346 si = sfp->sf_si; 1347 selfdfree(stp, sfp); 1348 /* If the selinfo wasn't cleared the event didn't fire. */ 1349 if (si != NULL) 1350 continue; 1351 fp = fdp->fd_ofiles[fd->fd]; 1352 #ifdef CAPABILITIES 1353 if ((fp == NULL) 1354 || (cap_funwrap(fp, CAP_POLL_EVENT, &fp) != 0)) { 1355 #else 1356 if (fp == NULL) { 1357 #endif 1358 fd->revents = POLLNVAL; 1359 n++; 1360 continue; 1361 } 1362 1363 /* 1364 * Note: backend also returns POLLHUP and 1365 * POLLERR if appropriate. 1366 */ 1367 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td); 1368 if (fd->revents != 0) 1369 n++; 1370 } 1371 FILEDESC_SUNLOCK(fdp); 1372 stp->st_flags = 0; 1373 td->td_retval[0] = n; 1374 return (0); 1375 } 1376 1377 1378 static int 1379 pollout(td, fds, ufds, nfd) 1380 struct thread *td; 1381 struct pollfd *fds; 1382 struct pollfd *ufds; 1383 u_int nfd; 1384 { 1385 int error = 0; 1386 u_int i = 0; 1387 u_int n = 0; 1388 1389 for (i = 0; i < nfd; i++) { 1390 error = copyout(&fds->revents, &ufds->revents, 1391 sizeof(ufds->revents)); 1392 if (error) 1393 return (error); 1394 if (fds->revents != 0) 1395 n++; 1396 fds++; 1397 ufds++; 1398 } 1399 td->td_retval[0] = n; 1400 return (0); 1401 } 1402 1403 static int 1404 pollscan(td, fds, nfd) 1405 struct thread *td; 1406 struct pollfd *fds; 1407 u_int nfd; 1408 { 1409 struct filedesc *fdp = td->td_proc->p_fd; 1410 int i; 1411 struct file *fp; 1412 int n = 0; 1413 1414 FILEDESC_SLOCK(fdp); 1415 for (i = 0; i < nfd; i++, fds++) { 1416 if (fds->fd >= fdp->fd_nfiles) { 1417 fds->revents = POLLNVAL; 1418 n++; 1419 } else if (fds->fd < 0) { 1420 fds->revents = 0; 1421 } else { 1422 fp = fdp->fd_ofiles[fds->fd]; 1423 #ifdef CAPABILITIES 1424 if ((fp == NULL) 1425 || (cap_funwrap(fp, CAP_POLL_EVENT, &fp) != 0)) { 1426 #else 1427 if (fp == NULL) { 1428 #endif 1429 fds->revents = POLLNVAL; 1430 n++; 1431 } else { 1432 /* 1433 * Note: backend also returns POLLHUP and 1434 * POLLERR if appropriate. 1435 */ 1436 selfdalloc(td, fds); 1437 fds->revents = fo_poll(fp, fds->events, 1438 td->td_ucred, td); 1439 /* 1440 * POSIX requires POLLOUT to be never 1441 * set simultaneously with POLLHUP. 1442 */ 1443 if ((fds->revents & POLLHUP) != 0) 1444 fds->revents &= ~POLLOUT; 1445 1446 if (fds->revents != 0) 1447 n++; 1448 } 1449 } 1450 } 1451 FILEDESC_SUNLOCK(fdp); 1452 td->td_retval[0] = n; 1453 return (0); 1454 } 1455 1456 /* 1457 * OpenBSD poll system call. 1458 * 1459 * XXX this isn't quite a true representation.. OpenBSD uses select ops. 1460 */ 1461 #ifndef _SYS_SYSPROTO_H_ 1462 struct openbsd_poll_args { 1463 struct pollfd *fds; 1464 u_int nfds; 1465 int timeout; 1466 }; 1467 #endif 1468 int 1469 sys_openbsd_poll(td, uap) 1470 register struct thread *td; 1471 register struct openbsd_poll_args *uap; 1472 { 1473 return (sys_poll(td, (struct poll_args *)uap)); 1474 } 1475 1476 /* 1477 * XXX This was created specifically to support netncp and netsmb. This 1478 * allows the caller to specify a socket to wait for events on. It returns 1479 * 0 if any events matched and an error otherwise. There is no way to 1480 * determine which events fired. 1481 */ 1482 int 1483 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td) 1484 { 1485 struct timeval atv, rtv, ttv; 1486 int error, timo; 1487 1488 if (tvp != NULL) { 1489 atv = *tvp; 1490 if (itimerfix(&atv)) 1491 return (EINVAL); 1492 getmicrouptime(&rtv); 1493 timevaladd(&atv, &rtv); 1494 } else { 1495 atv.tv_sec = 0; 1496 atv.tv_usec = 0; 1497 } 1498 1499 timo = 0; 1500 seltdinit(td); 1501 /* 1502 * Iterate until the timeout expires or the socket becomes ready. 1503 */ 1504 for (;;) { 1505 selfdalloc(td, NULL); 1506 error = sopoll(so, events, NULL, td); 1507 /* error here is actually the ready events. */ 1508 if (error) 1509 return (0); 1510 if (atv.tv_sec || atv.tv_usec) { 1511 getmicrouptime(&rtv); 1512 if (timevalcmp(&rtv, &atv, >=)) { 1513 seltdclear(td); 1514 return (EWOULDBLOCK); 1515 } 1516 ttv = atv; 1517 timevalsub(&ttv, &rtv); 1518 timo = ttv.tv_sec > 24 * 60 * 60 ? 1519 24 * 60 * 60 * hz : tvtohz(&ttv); 1520 } 1521 error = seltdwait(td, timo); 1522 seltdclear(td); 1523 if (error) 1524 break; 1525 } 1526 /* XXX Duplicates ncp/smb behavior. */ 1527 if (error == ERESTART) 1528 error = 0; 1529 return (error); 1530 } 1531 1532 /* 1533 * Preallocate two selfds associated with 'cookie'. Some fo_poll routines 1534 * have two select sets, one for read and another for write. 1535 */ 1536 static void 1537 selfdalloc(struct thread *td, void *cookie) 1538 { 1539 struct seltd *stp; 1540 1541 stp = td->td_sel; 1542 if (stp->st_free1 == NULL) 1543 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO); 1544 stp->st_free1->sf_td = stp; 1545 stp->st_free1->sf_cookie = cookie; 1546 if (stp->st_free2 == NULL) 1547 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO); 1548 stp->st_free2->sf_td = stp; 1549 stp->st_free2->sf_cookie = cookie; 1550 } 1551 1552 static void 1553 selfdfree(struct seltd *stp, struct selfd *sfp) 1554 { 1555 STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link); 1556 mtx_lock(sfp->sf_mtx); 1557 if (sfp->sf_si) 1558 TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads); 1559 mtx_unlock(sfp->sf_mtx); 1560 uma_zfree(selfd_zone, sfp); 1561 } 1562 1563 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */ 1564 void 1565 seldrain(sip) 1566 struct selinfo *sip; 1567 { 1568 1569 /* 1570 * This feature is already provided by doselwakeup(), thus it is 1571 * enough to go for it. 1572 * Eventually, the context, should take care to avoid races 1573 * between thread calling select()/poll() and file descriptor 1574 * detaching, but, again, the races are just the same as 1575 * selwakeup(). 1576 */ 1577 doselwakeup(sip, -1); 1578 } 1579 1580 /* 1581 * Record a select request. 1582 */ 1583 void 1584 selrecord(selector, sip) 1585 struct thread *selector; 1586 struct selinfo *sip; 1587 { 1588 struct selfd *sfp; 1589 struct seltd *stp; 1590 struct mtx *mtxp; 1591 1592 stp = selector->td_sel; 1593 /* 1594 * Don't record when doing a rescan. 1595 */ 1596 if (stp->st_flags & SELTD_RESCAN) 1597 return; 1598 /* 1599 * Grab one of the preallocated descriptors. 1600 */ 1601 sfp = NULL; 1602 if ((sfp = stp->st_free1) != NULL) 1603 stp->st_free1 = NULL; 1604 else if ((sfp = stp->st_free2) != NULL) 1605 stp->st_free2 = NULL; 1606 else 1607 panic("selrecord: No free selfd on selq"); 1608 mtxp = sip->si_mtx; 1609 if (mtxp == NULL) 1610 mtxp = mtx_pool_find(mtxpool_select, sip); 1611 /* 1612 * Initialize the sfp and queue it in the thread. 1613 */ 1614 sfp->sf_si = sip; 1615 sfp->sf_mtx = mtxp; 1616 STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link); 1617 /* 1618 * Now that we've locked the sip, check for initialization. 1619 */ 1620 mtx_lock(mtxp); 1621 if (sip->si_mtx == NULL) { 1622 sip->si_mtx = mtxp; 1623 TAILQ_INIT(&sip->si_tdlist); 1624 } 1625 /* 1626 * Add this thread to the list of selfds listening on this selinfo. 1627 */ 1628 TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads); 1629 mtx_unlock(sip->si_mtx); 1630 } 1631 1632 /* Wake up a selecting thread. */ 1633 void 1634 selwakeup(sip) 1635 struct selinfo *sip; 1636 { 1637 doselwakeup(sip, -1); 1638 } 1639 1640 /* Wake up a selecting thread, and set its priority. */ 1641 void 1642 selwakeuppri(sip, pri) 1643 struct selinfo *sip; 1644 int pri; 1645 { 1646 doselwakeup(sip, pri); 1647 } 1648 1649 /* 1650 * Do a wakeup when a selectable event occurs. 1651 */ 1652 static void 1653 doselwakeup(sip, pri) 1654 struct selinfo *sip; 1655 int pri; 1656 { 1657 struct selfd *sfp; 1658 struct selfd *sfn; 1659 struct seltd *stp; 1660 1661 /* If it's not initialized there can't be any waiters. */ 1662 if (sip->si_mtx == NULL) 1663 return; 1664 /* 1665 * Locking the selinfo locks all selfds associated with it. 1666 */ 1667 mtx_lock(sip->si_mtx); 1668 TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) { 1669 /* 1670 * Once we remove this sfp from the list and clear the 1671 * sf_si seltdclear will know to ignore this si. 1672 */ 1673 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads); 1674 sfp->sf_si = NULL; 1675 stp = sfp->sf_td; 1676 mtx_lock(&stp->st_mtx); 1677 stp->st_flags |= SELTD_PENDING; 1678 cv_broadcastpri(&stp->st_wait, pri); 1679 mtx_unlock(&stp->st_mtx); 1680 } 1681 mtx_unlock(sip->si_mtx); 1682 } 1683 1684 static void 1685 seltdinit(struct thread *td) 1686 { 1687 struct seltd *stp; 1688 1689 if ((stp = td->td_sel) != NULL) 1690 goto out; 1691 td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO); 1692 mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF); 1693 cv_init(&stp->st_wait, "select"); 1694 out: 1695 stp->st_flags = 0; 1696 STAILQ_INIT(&stp->st_selq); 1697 } 1698 1699 static int 1700 seltdwait(struct thread *td, int timo) 1701 { 1702 struct seltd *stp; 1703 int error; 1704 1705 stp = td->td_sel; 1706 /* 1707 * An event of interest may occur while we do not hold the seltd 1708 * locked so check the pending flag before we sleep. 1709 */ 1710 mtx_lock(&stp->st_mtx); 1711 /* 1712 * Any further calls to selrecord will be a rescan. 1713 */ 1714 stp->st_flags |= SELTD_RESCAN; 1715 if (stp->st_flags & SELTD_PENDING) { 1716 mtx_unlock(&stp->st_mtx); 1717 return (0); 1718 } 1719 if (timo > 0) 1720 error = cv_timedwait_sig(&stp->st_wait, &stp->st_mtx, timo); 1721 else 1722 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx); 1723 mtx_unlock(&stp->st_mtx); 1724 1725 return (error); 1726 } 1727 1728 void 1729 seltdfini(struct thread *td) 1730 { 1731 struct seltd *stp; 1732 1733 stp = td->td_sel; 1734 if (stp == NULL) 1735 return; 1736 if (stp->st_free1) 1737 uma_zfree(selfd_zone, stp->st_free1); 1738 if (stp->st_free2) 1739 uma_zfree(selfd_zone, stp->st_free2); 1740 td->td_sel = NULL; 1741 free(stp, M_SELECT); 1742 } 1743 1744 /* 1745 * Remove the references to the thread from all of the objects we were 1746 * polling. 1747 */ 1748 static void 1749 seltdclear(struct thread *td) 1750 { 1751 struct seltd *stp; 1752 struct selfd *sfp; 1753 struct selfd *sfn; 1754 1755 stp = td->td_sel; 1756 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) 1757 selfdfree(stp, sfp); 1758 stp->st_flags = 0; 1759 } 1760 1761 static void selectinit(void *); 1762 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL); 1763 static void 1764 selectinit(void *dummy __unused) 1765 { 1766 1767 selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL, 1768 NULL, NULL, UMA_ALIGN_PTR, 0); 1769 mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF); 1770 }
Cache object: 887504ac8c09da4f5f79c48ef954d7f6
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