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/9.0/sys/kern/sys_generic.c 228034 2011-11-27 19:00:52Z kib $"); 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 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer"); 78 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer"); 79 MALLOC_DEFINE(M_IOV, "iov", "large iov's"); 80 81 static int pollout(struct thread *, struct pollfd *, struct pollfd *, 82 u_int); 83 static int pollscan(struct thread *, struct pollfd *, u_int); 84 static int pollrescan(struct thread *); 85 static int selscan(struct thread *, fd_mask **, fd_mask **, int); 86 static int selrescan(struct thread *, fd_mask **, fd_mask **); 87 static void selfdalloc(struct thread *, void *); 88 static void selfdfree(struct seltd *, struct selfd *); 89 static int dofileread(struct thread *, int, struct file *, struct uio *, 90 off_t, int); 91 static int dofilewrite(struct thread *, int, struct file *, struct uio *, 92 off_t, int); 93 static void doselwakeup(struct selinfo *, int); 94 static void seltdinit(struct thread *); 95 static int seltdwait(struct thread *, int); 96 static void seltdclear(struct thread *); 97 98 /* 99 * One seltd per-thread allocated on demand as needed. 100 * 101 * t - protected by st_mtx 102 * k - Only accessed by curthread or read-only 103 */ 104 struct seltd { 105 STAILQ_HEAD(, selfd) st_selq; /* (k) List of selfds. */ 106 struct selfd *st_free1; /* (k) free fd for read set. */ 107 struct selfd *st_free2; /* (k) free fd for write set. */ 108 struct mtx st_mtx; /* Protects struct seltd */ 109 struct cv st_wait; /* (t) Wait channel. */ 110 int st_flags; /* (t) SELTD_ flags. */ 111 }; 112 113 #define SELTD_PENDING 0x0001 /* We have pending events. */ 114 #define SELTD_RESCAN 0x0002 /* Doing a rescan. */ 115 116 /* 117 * One selfd allocated per-thread per-file-descriptor. 118 * f - protected by sf_mtx 119 */ 120 struct selfd { 121 STAILQ_ENTRY(selfd) sf_link; /* (k) fds owned by this td. */ 122 TAILQ_ENTRY(selfd) sf_threads; /* (f) fds on this selinfo. */ 123 struct selinfo *sf_si; /* (f) selinfo when linked. */ 124 struct mtx *sf_mtx; /* Pointer to selinfo mtx. */ 125 struct seltd *sf_td; /* (k) owning seltd. */ 126 void *sf_cookie; /* (k) fd or pollfd. */ 127 }; 128 129 static uma_zone_t selfd_zone; 130 static struct mtx_pool *mtxpool_select; 131 132 #ifndef _SYS_SYSPROTO_H_ 133 struct read_args { 134 int fd; 135 void *buf; 136 size_t nbyte; 137 }; 138 #endif 139 int 140 sys_read(td, uap) 141 struct thread *td; 142 struct read_args *uap; 143 { 144 struct uio auio; 145 struct iovec aiov; 146 int error; 147 148 if (uap->nbyte > INT_MAX) 149 return (EINVAL); 150 aiov.iov_base = uap->buf; 151 aiov.iov_len = uap->nbyte; 152 auio.uio_iov = &aiov; 153 auio.uio_iovcnt = 1; 154 auio.uio_resid = uap->nbyte; 155 auio.uio_segflg = UIO_USERSPACE; 156 error = kern_readv(td, uap->fd, &auio); 157 return(error); 158 } 159 160 /* 161 * Positioned read system call 162 */ 163 #ifndef _SYS_SYSPROTO_H_ 164 struct pread_args { 165 int fd; 166 void *buf; 167 size_t nbyte; 168 int pad; 169 off_t offset; 170 }; 171 #endif 172 int 173 sys_pread(td, uap) 174 struct thread *td; 175 struct pread_args *uap; 176 { 177 struct uio auio; 178 struct iovec aiov; 179 int error; 180 181 if (uap->nbyte > INT_MAX) 182 return (EINVAL); 183 aiov.iov_base = uap->buf; 184 aiov.iov_len = uap->nbyte; 185 auio.uio_iov = &aiov; 186 auio.uio_iovcnt = 1; 187 auio.uio_resid = uap->nbyte; 188 auio.uio_segflg = UIO_USERSPACE; 189 error = kern_preadv(td, uap->fd, &auio, uap->offset); 190 return(error); 191 } 192 193 int 194 freebsd6_pread(td, uap) 195 struct thread *td; 196 struct freebsd6_pread_args *uap; 197 { 198 struct pread_args oargs; 199 200 oargs.fd = uap->fd; 201 oargs.buf = uap->buf; 202 oargs.nbyte = uap->nbyte; 203 oargs.offset = uap->offset; 204 return (sys_pread(td, &oargs)); 205 } 206 207 /* 208 * Scatter read system call. 209 */ 210 #ifndef _SYS_SYSPROTO_H_ 211 struct readv_args { 212 int fd; 213 struct iovec *iovp; 214 u_int iovcnt; 215 }; 216 #endif 217 int 218 sys_readv(struct thread *td, struct readv_args *uap) 219 { 220 struct uio *auio; 221 int error; 222 223 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 224 if (error) 225 return (error); 226 error = kern_readv(td, uap->fd, auio); 227 free(auio, M_IOV); 228 return (error); 229 } 230 231 int 232 kern_readv(struct thread *td, int fd, struct uio *auio) 233 { 234 struct file *fp; 235 int error; 236 237 error = fget_read(td, fd, CAP_READ | CAP_SEEK, &fp); 238 if (error) 239 return (error); 240 error = dofileread(td, fd, fp, auio, (off_t)-1, 0); 241 fdrop(fp, td); 242 return (error); 243 } 244 245 /* 246 * Scatter positioned read system call. 247 */ 248 #ifndef _SYS_SYSPROTO_H_ 249 struct preadv_args { 250 int fd; 251 struct iovec *iovp; 252 u_int iovcnt; 253 off_t offset; 254 }; 255 #endif 256 int 257 sys_preadv(struct thread *td, struct preadv_args *uap) 258 { 259 struct uio *auio; 260 int error; 261 262 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 263 if (error) 264 return (error); 265 error = kern_preadv(td, uap->fd, auio, uap->offset); 266 free(auio, M_IOV); 267 return (error); 268 } 269 270 int 271 kern_preadv(td, fd, auio, offset) 272 struct thread *td; 273 int fd; 274 struct uio *auio; 275 off_t offset; 276 { 277 struct file *fp; 278 int error; 279 280 error = fget_read(td, fd, CAP_READ, &fp); 281 if (error) 282 return (error); 283 if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE)) 284 error = ESPIPE; 285 else if (offset < 0 && fp->f_vnode->v_type != VCHR) 286 error = EINVAL; 287 else 288 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET); 289 fdrop(fp, td); 290 return (error); 291 } 292 293 /* 294 * Common code for readv and preadv that reads data in 295 * from a file using the passed in uio, offset, and flags. 296 */ 297 static int 298 dofileread(td, fd, fp, auio, offset, flags) 299 struct thread *td; 300 int fd; 301 struct file *fp; 302 struct uio *auio; 303 off_t offset; 304 int flags; 305 { 306 ssize_t cnt; 307 int error; 308 #ifdef KTRACE 309 struct uio *ktruio = NULL; 310 #endif 311 312 /* Finish zero length reads right here */ 313 if (auio->uio_resid == 0) { 314 td->td_retval[0] = 0; 315 return(0); 316 } 317 auio->uio_rw = UIO_READ; 318 auio->uio_offset = offset; 319 auio->uio_td = td; 320 #ifdef KTRACE 321 if (KTRPOINT(td, KTR_GENIO)) 322 ktruio = cloneuio(auio); 323 #endif 324 cnt = auio->uio_resid; 325 if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) { 326 if (auio->uio_resid != cnt && (error == ERESTART || 327 error == EINTR || error == EWOULDBLOCK)) 328 error = 0; 329 } 330 cnt -= auio->uio_resid; 331 #ifdef KTRACE 332 if (ktruio != NULL) { 333 ktruio->uio_resid = cnt; 334 ktrgenio(fd, UIO_READ, ktruio, error); 335 } 336 #endif 337 td->td_retval[0] = cnt; 338 return (error); 339 } 340 341 #ifndef _SYS_SYSPROTO_H_ 342 struct write_args { 343 int fd; 344 const void *buf; 345 size_t nbyte; 346 }; 347 #endif 348 int 349 sys_write(td, uap) 350 struct thread *td; 351 struct write_args *uap; 352 { 353 struct uio auio; 354 struct iovec aiov; 355 int error; 356 357 if (uap->nbyte > INT_MAX) 358 return (EINVAL); 359 aiov.iov_base = (void *)(uintptr_t)uap->buf; 360 aiov.iov_len = uap->nbyte; 361 auio.uio_iov = &aiov; 362 auio.uio_iovcnt = 1; 363 auio.uio_resid = uap->nbyte; 364 auio.uio_segflg = UIO_USERSPACE; 365 error = kern_writev(td, uap->fd, &auio); 366 return(error); 367 } 368 369 /* 370 * Positioned write system call. 371 */ 372 #ifndef _SYS_SYSPROTO_H_ 373 struct pwrite_args { 374 int fd; 375 const void *buf; 376 size_t nbyte; 377 int pad; 378 off_t offset; 379 }; 380 #endif 381 int 382 sys_pwrite(td, uap) 383 struct thread *td; 384 struct pwrite_args *uap; 385 { 386 struct uio auio; 387 struct iovec aiov; 388 int error; 389 390 if (uap->nbyte > INT_MAX) 391 return (EINVAL); 392 aiov.iov_base = (void *)(uintptr_t)uap->buf; 393 aiov.iov_len = uap->nbyte; 394 auio.uio_iov = &aiov; 395 auio.uio_iovcnt = 1; 396 auio.uio_resid = uap->nbyte; 397 auio.uio_segflg = UIO_USERSPACE; 398 error = kern_pwritev(td, uap->fd, &auio, uap->offset); 399 return(error); 400 } 401 402 int 403 freebsd6_pwrite(td, uap) 404 struct thread *td; 405 struct freebsd6_pwrite_args *uap; 406 { 407 struct pwrite_args oargs; 408 409 oargs.fd = uap->fd; 410 oargs.buf = uap->buf; 411 oargs.nbyte = uap->nbyte; 412 oargs.offset = uap->offset; 413 return (sys_pwrite(td, &oargs)); 414 } 415 416 /* 417 * Gather write system call. 418 */ 419 #ifndef _SYS_SYSPROTO_H_ 420 struct writev_args { 421 int fd; 422 struct iovec *iovp; 423 u_int iovcnt; 424 }; 425 #endif 426 int 427 sys_writev(struct thread *td, struct writev_args *uap) 428 { 429 struct uio *auio; 430 int error; 431 432 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 433 if (error) 434 return (error); 435 error = kern_writev(td, uap->fd, auio); 436 free(auio, M_IOV); 437 return (error); 438 } 439 440 int 441 kern_writev(struct thread *td, int fd, struct uio *auio) 442 { 443 struct file *fp; 444 int error; 445 446 error = fget_write(td, fd, CAP_WRITE | CAP_SEEK, &fp); 447 if (error) 448 return (error); 449 error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0); 450 fdrop(fp, td); 451 return (error); 452 } 453 454 /* 455 * Gather positioned write system call. 456 */ 457 #ifndef _SYS_SYSPROTO_H_ 458 struct pwritev_args { 459 int fd; 460 struct iovec *iovp; 461 u_int iovcnt; 462 off_t offset; 463 }; 464 #endif 465 int 466 sys_pwritev(struct thread *td, struct pwritev_args *uap) 467 { 468 struct uio *auio; 469 int error; 470 471 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 472 if (error) 473 return (error); 474 error = kern_pwritev(td, uap->fd, auio, uap->offset); 475 free(auio, M_IOV); 476 return (error); 477 } 478 479 int 480 kern_pwritev(td, fd, auio, offset) 481 struct thread *td; 482 struct uio *auio; 483 int fd; 484 off_t offset; 485 { 486 struct file *fp; 487 int error; 488 489 error = fget_write(td, fd, CAP_WRITE, &fp); 490 if (error) 491 return (error); 492 if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE)) 493 error = ESPIPE; 494 else if (offset < 0 && fp->f_vnode->v_type != VCHR) 495 error = EINVAL; 496 else 497 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET); 498 fdrop(fp, td); 499 return (error); 500 } 501 502 /* 503 * Common code for writev and pwritev that writes data to 504 * a file using the passed in uio, offset, and flags. 505 */ 506 static int 507 dofilewrite(td, fd, fp, auio, offset, flags) 508 struct thread *td; 509 int fd; 510 struct file *fp; 511 struct uio *auio; 512 off_t offset; 513 int flags; 514 { 515 ssize_t cnt; 516 int error; 517 #ifdef KTRACE 518 struct uio *ktruio = NULL; 519 #endif 520 521 auio->uio_rw = UIO_WRITE; 522 auio->uio_td = td; 523 auio->uio_offset = offset; 524 #ifdef KTRACE 525 if (KTRPOINT(td, KTR_GENIO)) 526 ktruio = cloneuio(auio); 527 #endif 528 cnt = auio->uio_resid; 529 if (fp->f_type == DTYPE_VNODE) 530 bwillwrite(); 531 if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) { 532 if (auio->uio_resid != cnt && (error == ERESTART || 533 error == EINTR || error == EWOULDBLOCK)) 534 error = 0; 535 /* Socket layer is responsible for issuing SIGPIPE. */ 536 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) { 537 PROC_LOCK(td->td_proc); 538 tdsignal(td, SIGPIPE); 539 PROC_UNLOCK(td->td_proc); 540 } 541 } 542 cnt -= auio->uio_resid; 543 #ifdef KTRACE 544 if (ktruio != NULL) { 545 ktruio->uio_resid = cnt; 546 ktrgenio(fd, UIO_WRITE, ktruio, error); 547 } 548 #endif 549 td->td_retval[0] = cnt; 550 return (error); 551 } 552 553 /* 554 * Truncate a file given a file descriptor. 555 * 556 * Can't use fget_write() here, since must return EINVAL and not EBADF if the 557 * descriptor isn't writable. 558 */ 559 int 560 kern_ftruncate(td, fd, length) 561 struct thread *td; 562 int fd; 563 off_t length; 564 { 565 struct file *fp; 566 int error; 567 568 AUDIT_ARG_FD(fd); 569 if (length < 0) 570 return (EINVAL); 571 error = fget(td, fd, CAP_FTRUNCATE, &fp); 572 if (error) 573 return (error); 574 AUDIT_ARG_FILE(td->td_proc, fp); 575 if (!(fp->f_flag & FWRITE)) { 576 fdrop(fp, td); 577 return (EINVAL); 578 } 579 error = fo_truncate(fp, length, td->td_ucred, td); 580 fdrop(fp, td); 581 return (error); 582 } 583 584 #ifndef _SYS_SYSPROTO_H_ 585 struct ftruncate_args { 586 int fd; 587 int pad; 588 off_t length; 589 }; 590 #endif 591 int 592 sys_ftruncate(td, uap) 593 struct thread *td; 594 struct ftruncate_args *uap; 595 { 596 597 return (kern_ftruncate(td, uap->fd, uap->length)); 598 } 599 600 #if defined(COMPAT_43) 601 #ifndef _SYS_SYSPROTO_H_ 602 struct oftruncate_args { 603 int fd; 604 long length; 605 }; 606 #endif 607 int 608 oftruncate(td, uap) 609 struct thread *td; 610 struct oftruncate_args *uap; 611 { 612 613 return (kern_ftruncate(td, uap->fd, uap->length)); 614 } 615 #endif /* COMPAT_43 */ 616 617 #ifndef _SYS_SYSPROTO_H_ 618 struct ioctl_args { 619 int fd; 620 u_long com; 621 caddr_t data; 622 }; 623 #endif 624 /* ARGSUSED */ 625 int 626 sys_ioctl(struct thread *td, struct ioctl_args *uap) 627 { 628 u_long com; 629 int arg, error; 630 u_int size; 631 caddr_t data; 632 633 if (uap->com > 0xffffffff) { 634 printf( 635 "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n", 636 td->td_proc->p_pid, td->td_name, uap->com); 637 uap->com &= 0xffffffff; 638 } 639 com = uap->com; 640 641 /* 642 * Interpret high order word to find amount of data to be 643 * copied to/from the user's address space. 644 */ 645 size = IOCPARM_LEN(com); 646 if ((size > IOCPARM_MAX) || 647 ((com & (IOC_VOID | IOC_IN | IOC_OUT)) == 0) || 648 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43) 649 ((com & IOC_OUT) && size == 0) || 650 #else 651 ((com & (IOC_IN | IOC_OUT)) && size == 0) || 652 #endif 653 ((com & IOC_VOID) && size > 0 && size != sizeof(int))) 654 return (ENOTTY); 655 656 if (size > 0) { 657 if (com & IOC_VOID) { 658 /* Integer argument. */ 659 arg = (intptr_t)uap->data; 660 data = (void *)&arg; 661 size = 0; 662 } else 663 data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK); 664 } else 665 data = (void *)&uap->data; 666 if (com & IOC_IN) { 667 error = copyin(uap->data, data, (u_int)size); 668 if (error) { 669 if (size > 0) 670 free(data, M_IOCTLOPS); 671 return (error); 672 } 673 } else if (com & IOC_OUT) { 674 /* 675 * Zero the buffer so the user always 676 * gets back something deterministic. 677 */ 678 bzero(data, size); 679 } 680 681 error = kern_ioctl(td, uap->fd, com, data); 682 683 if (error == 0 && (com & IOC_OUT)) 684 error = copyout(data, uap->data, (u_int)size); 685 686 if (size > 0) 687 free(data, M_IOCTLOPS); 688 return (error); 689 } 690 691 int 692 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data) 693 { 694 struct file *fp; 695 struct filedesc *fdp; 696 int error; 697 int tmp; 698 699 AUDIT_ARG_FD(fd); 700 AUDIT_ARG_CMD(com); 701 if ((error = fget(td, fd, CAP_IOCTL, &fp)) != 0) 702 return (error); 703 if ((fp->f_flag & (FREAD | FWRITE)) == 0) { 704 fdrop(fp, td); 705 return (EBADF); 706 } 707 fdp = td->td_proc->p_fd; 708 switch (com) { 709 case FIONCLEX: 710 FILEDESC_XLOCK(fdp); 711 fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE; 712 FILEDESC_XUNLOCK(fdp); 713 goto out; 714 case FIOCLEX: 715 FILEDESC_XLOCK(fdp); 716 fdp->fd_ofileflags[fd] |= UF_EXCLOSE; 717 FILEDESC_XUNLOCK(fdp); 718 goto out; 719 case FIONBIO: 720 if ((tmp = *(int *)data)) 721 atomic_set_int(&fp->f_flag, FNONBLOCK); 722 else 723 atomic_clear_int(&fp->f_flag, FNONBLOCK); 724 data = (void *)&tmp; 725 break; 726 case FIOASYNC: 727 if ((tmp = *(int *)data)) 728 atomic_set_int(&fp->f_flag, FASYNC); 729 else 730 atomic_clear_int(&fp->f_flag, FASYNC); 731 data = (void *)&tmp; 732 break; 733 } 734 735 error = fo_ioctl(fp, com, data, td->td_ucred, td); 736 out: 737 fdrop(fp, td); 738 return (error); 739 } 740 741 int 742 poll_no_poll(int events) 743 { 744 /* 745 * Return true for read/write. If the user asked for something 746 * special, return POLLNVAL, so that clients have a way of 747 * determining reliably whether or not the extended 748 * functionality is present without hard-coding knowledge 749 * of specific filesystem implementations. 750 */ 751 if (events & ~POLLSTANDARD) 752 return (POLLNVAL); 753 754 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 755 } 756 757 int 758 sys_pselect(struct thread *td, struct pselect_args *uap) 759 { 760 struct timespec ts; 761 struct timeval tv, *tvp; 762 sigset_t set, *uset; 763 int error; 764 765 if (uap->ts != NULL) { 766 error = copyin(uap->ts, &ts, sizeof(ts)); 767 if (error != 0) 768 return (error); 769 TIMESPEC_TO_TIMEVAL(&tv, &ts); 770 tvp = &tv; 771 } else 772 tvp = NULL; 773 if (uap->sm != NULL) { 774 error = copyin(uap->sm, &set, sizeof(set)); 775 if (error != 0) 776 return (error); 777 uset = &set; 778 } else 779 uset = NULL; 780 return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp, 781 uset, NFDBITS)); 782 } 783 784 int 785 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex, 786 struct timeval *tvp, sigset_t *uset, int abi_nfdbits) 787 { 788 int error; 789 790 if (uset != NULL) { 791 error = kern_sigprocmask(td, SIG_SETMASK, uset, 792 &td->td_oldsigmask, 0); 793 if (error != 0) 794 return (error); 795 td->td_pflags |= TDP_OLDMASK; 796 /* 797 * Make sure that ast() is called on return to 798 * usermode and TDP_OLDMASK is cleared, restoring old 799 * sigmask. 800 */ 801 thread_lock(td); 802 td->td_flags |= TDF_ASTPENDING; 803 thread_unlock(td); 804 } 805 error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits); 806 return (error); 807 } 808 809 #ifndef _SYS_SYSPROTO_H_ 810 struct select_args { 811 int nd; 812 fd_set *in, *ou, *ex; 813 struct timeval *tv; 814 }; 815 #endif 816 int 817 sys_select(struct thread *td, struct select_args *uap) 818 { 819 struct timeval tv, *tvp; 820 int error; 821 822 if (uap->tv != NULL) { 823 error = copyin(uap->tv, &tv, sizeof(tv)); 824 if (error) 825 return (error); 826 tvp = &tv; 827 } else 828 tvp = NULL; 829 830 return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp, 831 NFDBITS)); 832 } 833 834 /* 835 * In the unlikely case when user specified n greater then the last 836 * open file descriptor, check that no bits are set after the last 837 * valid fd. We must return EBADF if any is set. 838 * 839 * There are applications that rely on the behaviour. 840 * 841 * nd is fd_lastfile + 1. 842 */ 843 static int 844 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits) 845 { 846 char *addr, *oaddr; 847 int b, i, res; 848 uint8_t bits; 849 850 if (nd >= ndu || fd_in == NULL) 851 return (0); 852 853 oaddr = NULL; 854 bits = 0; /* silence gcc */ 855 for (i = nd; i < ndu; i++) { 856 b = i / NBBY; 857 #if BYTE_ORDER == LITTLE_ENDIAN 858 addr = (char *)fd_in + b; 859 #else 860 addr = (char *)fd_in; 861 if (abi_nfdbits == NFDBITS) { 862 addr += rounddown(b, sizeof(fd_mask)) + 863 sizeof(fd_mask) - 1 - b % sizeof(fd_mask); 864 } else { 865 addr += rounddown(b, sizeof(uint32_t)) + 866 sizeof(uint32_t) - 1 - b % sizeof(uint32_t); 867 } 868 #endif 869 if (addr != oaddr) { 870 res = fubyte(addr); 871 if (res == -1) 872 return (EFAULT); 873 oaddr = addr; 874 bits = res; 875 } 876 if ((bits & (1 << (i % NBBY))) != 0) 877 return (EBADF); 878 } 879 return (0); 880 } 881 882 int 883 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou, 884 fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits) 885 { 886 struct filedesc *fdp; 887 /* 888 * The magic 2048 here is chosen to be just enough for FD_SETSIZE 889 * infds with the new FD_SETSIZE of 1024, and more than enough for 890 * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE 891 * of 256. 892 */ 893 fd_mask s_selbits[howmany(2048, NFDBITS)]; 894 fd_mask *ibits[3], *obits[3], *selbits, *sbp; 895 struct timeval atv, rtv, ttv; 896 int error, lf, ndu, timo; 897 u_int nbufbytes, ncpbytes, ncpubytes, nfdbits; 898 899 if (nd < 0) 900 return (EINVAL); 901 fdp = td->td_proc->p_fd; 902 ndu = nd; 903 lf = fdp->fd_lastfile; 904 if (nd > lf + 1) 905 nd = lf + 1; 906 907 error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits); 908 if (error != 0) 909 return (error); 910 error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits); 911 if (error != 0) 912 return (error); 913 error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits); 914 if (error != 0) 915 return (error); 916 917 /* 918 * Allocate just enough bits for the non-null fd_sets. Use the 919 * preallocated auto buffer if possible. 920 */ 921 nfdbits = roundup(nd, NFDBITS); 922 ncpbytes = nfdbits / NBBY; 923 ncpubytes = roundup(nd, abi_nfdbits) / NBBY; 924 nbufbytes = 0; 925 if (fd_in != NULL) 926 nbufbytes += 2 * ncpbytes; 927 if (fd_ou != NULL) 928 nbufbytes += 2 * ncpbytes; 929 if (fd_ex != NULL) 930 nbufbytes += 2 * ncpbytes; 931 if (nbufbytes <= sizeof s_selbits) 932 selbits = &s_selbits[0]; 933 else 934 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK); 935 936 /* 937 * Assign pointers into the bit buffers and fetch the input bits. 938 * Put the output buffers together so that they can be bzeroed 939 * together. 940 */ 941 sbp = selbits; 942 #define getbits(name, x) \ 943 do { \ 944 if (name == NULL) { \ 945 ibits[x] = NULL; \ 946 obits[x] = NULL; \ 947 } else { \ 948 ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp; \ 949 obits[x] = sbp; \ 950 sbp += ncpbytes / sizeof *sbp; \ 951 error = copyin(name, ibits[x], ncpubytes); \ 952 if (error != 0) \ 953 goto done; \ 954 bzero((char *)ibits[x] + ncpubytes, \ 955 ncpbytes - ncpubytes); \ 956 } \ 957 } while (0) 958 getbits(fd_in, 0); 959 getbits(fd_ou, 1); 960 getbits(fd_ex, 2); 961 #undef getbits 962 963 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__) 964 /* 965 * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS, 966 * we are running under 32-bit emulation. This should be more 967 * generic. 968 */ 969 #define swizzle_fdset(bits) \ 970 if (abi_nfdbits != NFDBITS && bits != NULL) { \ 971 int i; \ 972 for (i = 0; i < ncpbytes / sizeof *sbp; i++) \ 973 bits[i] = (bits[i] >> 32) | (bits[i] << 32); \ 974 } 975 #else 976 #define swizzle_fdset(bits) 977 #endif 978 979 /* Make sure the bit order makes it through an ABI transition */ 980 swizzle_fdset(ibits[0]); 981 swizzle_fdset(ibits[1]); 982 swizzle_fdset(ibits[2]); 983 984 if (nbufbytes != 0) 985 bzero(selbits, nbufbytes / 2); 986 987 if (tvp != NULL) { 988 atv = *tvp; 989 if (itimerfix(&atv)) { 990 error = EINVAL; 991 goto done; 992 } 993 getmicrouptime(&rtv); 994 timevaladd(&atv, &rtv); 995 } else { 996 atv.tv_sec = 0; 997 atv.tv_usec = 0; 998 } 999 timo = 0; 1000 seltdinit(td); 1001 /* Iterate until the timeout expires or descriptors become ready. */ 1002 for (;;) { 1003 error = selscan(td, ibits, obits, nd); 1004 if (error || td->td_retval[0] != 0) 1005 break; 1006 if (atv.tv_sec || atv.tv_usec) { 1007 getmicrouptime(&rtv); 1008 if (timevalcmp(&rtv, &atv, >=)) 1009 break; 1010 ttv = atv; 1011 timevalsub(&ttv, &rtv); 1012 timo = ttv.tv_sec > 24 * 60 * 60 ? 1013 24 * 60 * 60 * hz : tvtohz(&ttv); 1014 } 1015 error = seltdwait(td, timo); 1016 if (error) 1017 break; 1018 error = selrescan(td, ibits, obits); 1019 if (error || td->td_retval[0] != 0) 1020 break; 1021 } 1022 seltdclear(td); 1023 1024 done: 1025 /* select is not restarted after signals... */ 1026 if (error == ERESTART) 1027 error = EINTR; 1028 if (error == EWOULDBLOCK) 1029 error = 0; 1030 1031 /* swizzle bit order back, if necessary */ 1032 swizzle_fdset(obits[0]); 1033 swizzle_fdset(obits[1]); 1034 swizzle_fdset(obits[2]); 1035 #undef swizzle_fdset 1036 1037 #define putbits(name, x) \ 1038 if (name && (error2 = copyout(obits[x], name, ncpubytes))) \ 1039 error = error2; 1040 if (error == 0) { 1041 int error2; 1042 1043 putbits(fd_in, 0); 1044 putbits(fd_ou, 1); 1045 putbits(fd_ex, 2); 1046 #undef putbits 1047 } 1048 if (selbits != &s_selbits[0]) 1049 free(selbits, M_SELECT); 1050 1051 return (error); 1052 } 1053 /* 1054 * Convert a select bit set to poll flags. 1055 * 1056 * The backend always returns POLLHUP/POLLERR if appropriate and we 1057 * return this as a set bit in any set. 1058 */ 1059 static int select_flags[3] = { 1060 POLLRDNORM | POLLHUP | POLLERR, 1061 POLLWRNORM | POLLHUP | POLLERR, 1062 POLLRDBAND | POLLERR 1063 }; 1064 1065 /* 1066 * Compute the fo_poll flags required for a fd given by the index and 1067 * bit position in the fd_mask array. 1068 */ 1069 static __inline int 1070 selflags(fd_mask **ibits, int idx, fd_mask bit) 1071 { 1072 int flags; 1073 int msk; 1074 1075 flags = 0; 1076 for (msk = 0; msk < 3; msk++) { 1077 if (ibits[msk] == NULL) 1078 continue; 1079 if ((ibits[msk][idx] & bit) == 0) 1080 continue; 1081 flags |= select_flags[msk]; 1082 } 1083 return (flags); 1084 } 1085 1086 /* 1087 * Set the appropriate output bits given a mask of fired events and the 1088 * input bits originally requested. 1089 */ 1090 static __inline int 1091 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events) 1092 { 1093 int msk; 1094 int n; 1095 1096 n = 0; 1097 for (msk = 0; msk < 3; msk++) { 1098 if ((events & select_flags[msk]) == 0) 1099 continue; 1100 if (ibits[msk] == NULL) 1101 continue; 1102 if ((ibits[msk][idx] & bit) == 0) 1103 continue; 1104 /* 1105 * XXX Check for a duplicate set. This can occur because a 1106 * socket calls selrecord() twice for each poll() call 1107 * resulting in two selfds per real fd. selrescan() will 1108 * call selsetbits twice as a result. 1109 */ 1110 if ((obits[msk][idx] & bit) != 0) 1111 continue; 1112 obits[msk][idx] |= bit; 1113 n++; 1114 } 1115 1116 return (n); 1117 } 1118 1119 static __inline int 1120 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp) 1121 { 1122 struct file *fp; 1123 #ifdef CAPABILITIES 1124 struct file *fp_fromcap; 1125 int error; 1126 #endif 1127 1128 if ((fp = fget_unlocked(fdp, fd)) == NULL) 1129 return (EBADF); 1130 #ifdef CAPABILITIES 1131 /* 1132 * If the file descriptor is for a capability, test rights and use 1133 * the file descriptor references by the capability. 1134 */ 1135 error = cap_funwrap(fp, CAP_POLL_EVENT, &fp_fromcap); 1136 if (error) { 1137 fdrop(fp, curthread); 1138 return (error); 1139 } 1140 if (fp != fp_fromcap) { 1141 fhold(fp_fromcap); 1142 fdrop(fp, curthread); 1143 fp = fp_fromcap; 1144 } 1145 #endif /* CAPABILITIES */ 1146 *fpp = fp; 1147 return (0); 1148 } 1149 1150 /* 1151 * Traverse the list of fds attached to this thread's seltd and check for 1152 * completion. 1153 */ 1154 static int 1155 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits) 1156 { 1157 struct filedesc *fdp; 1158 struct selinfo *si; 1159 struct seltd *stp; 1160 struct selfd *sfp; 1161 struct selfd *sfn; 1162 struct file *fp; 1163 fd_mask bit; 1164 int fd, ev, n, idx; 1165 int error; 1166 1167 fdp = td->td_proc->p_fd; 1168 stp = td->td_sel; 1169 n = 0; 1170 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) { 1171 fd = (int)(uintptr_t)sfp->sf_cookie; 1172 si = sfp->sf_si; 1173 selfdfree(stp, sfp); 1174 /* If the selinfo wasn't cleared the event didn't fire. */ 1175 if (si != NULL) 1176 continue; 1177 error = getselfd_cap(fdp, fd, &fp); 1178 if (error) 1179 return (error); 1180 idx = fd / NFDBITS; 1181 bit = (fd_mask)1 << (fd % NFDBITS); 1182 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td); 1183 fdrop(fp, td); 1184 if (ev != 0) 1185 n += selsetbits(ibits, obits, idx, bit, ev); 1186 } 1187 stp->st_flags = 0; 1188 td->td_retval[0] = n; 1189 return (0); 1190 } 1191 1192 /* 1193 * Perform the initial filedescriptor scan and register ourselves with 1194 * each selinfo. 1195 */ 1196 static int 1197 selscan(td, ibits, obits, nfd) 1198 struct thread *td; 1199 fd_mask **ibits, **obits; 1200 int nfd; 1201 { 1202 struct filedesc *fdp; 1203 struct file *fp; 1204 fd_mask bit; 1205 int ev, flags, end, fd; 1206 int n, idx; 1207 int error; 1208 1209 fdp = td->td_proc->p_fd; 1210 n = 0; 1211 for (idx = 0, fd = 0; fd < nfd; idx++) { 1212 end = imin(fd + NFDBITS, nfd); 1213 for (bit = 1; fd < end; bit <<= 1, fd++) { 1214 /* Compute the list of events we're interested in. */ 1215 flags = selflags(ibits, idx, bit); 1216 if (flags == 0) 1217 continue; 1218 error = getselfd_cap(fdp, fd, &fp); 1219 if (error) 1220 return (error); 1221 selfdalloc(td, (void *)(uintptr_t)fd); 1222 ev = fo_poll(fp, flags, td->td_ucred, td); 1223 fdrop(fp, td); 1224 if (ev != 0) 1225 n += selsetbits(ibits, obits, idx, bit, ev); 1226 } 1227 } 1228 1229 td->td_retval[0] = n; 1230 return (0); 1231 } 1232 1233 #ifndef _SYS_SYSPROTO_H_ 1234 struct poll_args { 1235 struct pollfd *fds; 1236 u_int nfds; 1237 int timeout; 1238 }; 1239 #endif 1240 int 1241 sys_poll(td, uap) 1242 struct thread *td; 1243 struct poll_args *uap; 1244 { 1245 struct pollfd *bits; 1246 struct pollfd smallbits[32]; 1247 struct timeval atv, rtv, ttv; 1248 int error = 0, timo; 1249 u_int nfds; 1250 size_t ni; 1251 1252 nfds = uap->nfds; 1253 if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 1254 return (EINVAL); 1255 ni = nfds * sizeof(struct pollfd); 1256 if (ni > sizeof(smallbits)) 1257 bits = malloc(ni, M_TEMP, M_WAITOK); 1258 else 1259 bits = smallbits; 1260 error = copyin(uap->fds, bits, ni); 1261 if (error) 1262 goto done; 1263 if (uap->timeout != INFTIM) { 1264 atv.tv_sec = uap->timeout / 1000; 1265 atv.tv_usec = (uap->timeout % 1000) * 1000; 1266 if (itimerfix(&atv)) { 1267 error = EINVAL; 1268 goto done; 1269 } 1270 getmicrouptime(&rtv); 1271 timevaladd(&atv, &rtv); 1272 } else { 1273 atv.tv_sec = 0; 1274 atv.tv_usec = 0; 1275 } 1276 timo = 0; 1277 seltdinit(td); 1278 /* Iterate until the timeout expires or descriptors become ready. */ 1279 for (;;) { 1280 error = pollscan(td, bits, nfds); 1281 if (error || td->td_retval[0] != 0) 1282 break; 1283 if (atv.tv_sec || atv.tv_usec) { 1284 getmicrouptime(&rtv); 1285 if (timevalcmp(&rtv, &atv, >=)) 1286 break; 1287 ttv = atv; 1288 timevalsub(&ttv, &rtv); 1289 timo = ttv.tv_sec > 24 * 60 * 60 ? 1290 24 * 60 * 60 * hz : tvtohz(&ttv); 1291 } 1292 error = seltdwait(td, timo); 1293 if (error) 1294 break; 1295 error = pollrescan(td); 1296 if (error || td->td_retval[0] != 0) 1297 break; 1298 } 1299 seltdclear(td); 1300 1301 done: 1302 /* poll is not restarted after signals... */ 1303 if (error == ERESTART) 1304 error = EINTR; 1305 if (error == EWOULDBLOCK) 1306 error = 0; 1307 if (error == 0) { 1308 error = pollout(td, bits, uap->fds, nfds); 1309 if (error) 1310 goto out; 1311 } 1312 out: 1313 if (ni > sizeof(smallbits)) 1314 free(bits, M_TEMP); 1315 return (error); 1316 } 1317 1318 static int 1319 pollrescan(struct thread *td) 1320 { 1321 struct seltd *stp; 1322 struct selfd *sfp; 1323 struct selfd *sfn; 1324 struct selinfo *si; 1325 struct filedesc *fdp; 1326 struct file *fp; 1327 struct pollfd *fd; 1328 int n; 1329 1330 n = 0; 1331 fdp = td->td_proc->p_fd; 1332 stp = td->td_sel; 1333 FILEDESC_SLOCK(fdp); 1334 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) { 1335 fd = (struct pollfd *)sfp->sf_cookie; 1336 si = sfp->sf_si; 1337 selfdfree(stp, sfp); 1338 /* If the selinfo wasn't cleared the event didn't fire. */ 1339 if (si != NULL) 1340 continue; 1341 fp = fdp->fd_ofiles[fd->fd]; 1342 #ifdef CAPABILITIES 1343 if ((fp == NULL) 1344 || (cap_funwrap(fp, CAP_POLL_EVENT, &fp) != 0)) { 1345 #else 1346 if (fp == NULL) { 1347 #endif 1348 fd->revents = POLLNVAL; 1349 n++; 1350 continue; 1351 } 1352 1353 /* 1354 * Note: backend also returns POLLHUP and 1355 * POLLERR if appropriate. 1356 */ 1357 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td); 1358 if (fd->revents != 0) 1359 n++; 1360 } 1361 FILEDESC_SUNLOCK(fdp); 1362 stp->st_flags = 0; 1363 td->td_retval[0] = n; 1364 return (0); 1365 } 1366 1367 1368 static int 1369 pollout(td, fds, ufds, nfd) 1370 struct thread *td; 1371 struct pollfd *fds; 1372 struct pollfd *ufds; 1373 u_int nfd; 1374 { 1375 int error = 0; 1376 u_int i = 0; 1377 u_int n = 0; 1378 1379 for (i = 0; i < nfd; i++) { 1380 error = copyout(&fds->revents, &ufds->revents, 1381 sizeof(ufds->revents)); 1382 if (error) 1383 return (error); 1384 if (fds->revents != 0) 1385 n++; 1386 fds++; 1387 ufds++; 1388 } 1389 td->td_retval[0] = n; 1390 return (0); 1391 } 1392 1393 static int 1394 pollscan(td, fds, nfd) 1395 struct thread *td; 1396 struct pollfd *fds; 1397 u_int nfd; 1398 { 1399 struct filedesc *fdp = td->td_proc->p_fd; 1400 int i; 1401 struct file *fp; 1402 int n = 0; 1403 1404 FILEDESC_SLOCK(fdp); 1405 for (i = 0; i < nfd; i++, fds++) { 1406 if (fds->fd >= fdp->fd_nfiles) { 1407 fds->revents = POLLNVAL; 1408 n++; 1409 } else if (fds->fd < 0) { 1410 fds->revents = 0; 1411 } else { 1412 fp = fdp->fd_ofiles[fds->fd]; 1413 #ifdef CAPABILITIES 1414 if ((fp == NULL) 1415 || (cap_funwrap(fp, CAP_POLL_EVENT, &fp) != 0)) { 1416 #else 1417 if (fp == NULL) { 1418 #endif 1419 fds->revents = POLLNVAL; 1420 n++; 1421 } else { 1422 /* 1423 * Note: backend also returns POLLHUP and 1424 * POLLERR if appropriate. 1425 */ 1426 selfdalloc(td, fds); 1427 fds->revents = fo_poll(fp, fds->events, 1428 td->td_ucred, td); 1429 /* 1430 * POSIX requires POLLOUT to be never 1431 * set simultaneously with POLLHUP. 1432 */ 1433 if ((fds->revents & POLLHUP) != 0) 1434 fds->revents &= ~POLLOUT; 1435 1436 if (fds->revents != 0) 1437 n++; 1438 } 1439 } 1440 } 1441 FILEDESC_SUNLOCK(fdp); 1442 td->td_retval[0] = n; 1443 return (0); 1444 } 1445 1446 /* 1447 * OpenBSD poll system call. 1448 * 1449 * XXX this isn't quite a true representation.. OpenBSD uses select ops. 1450 */ 1451 #ifndef _SYS_SYSPROTO_H_ 1452 struct openbsd_poll_args { 1453 struct pollfd *fds; 1454 u_int nfds; 1455 int timeout; 1456 }; 1457 #endif 1458 int 1459 sys_openbsd_poll(td, uap) 1460 register struct thread *td; 1461 register struct openbsd_poll_args *uap; 1462 { 1463 return (sys_poll(td, (struct poll_args *)uap)); 1464 } 1465 1466 /* 1467 * XXX This was created specifically to support netncp and netsmb. This 1468 * allows the caller to specify a socket to wait for events on. It returns 1469 * 0 if any events matched and an error otherwise. There is no way to 1470 * determine which events fired. 1471 */ 1472 int 1473 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td) 1474 { 1475 struct timeval atv, rtv, ttv; 1476 int error, timo; 1477 1478 if (tvp != NULL) { 1479 atv = *tvp; 1480 if (itimerfix(&atv)) 1481 return (EINVAL); 1482 getmicrouptime(&rtv); 1483 timevaladd(&atv, &rtv); 1484 } else { 1485 atv.tv_sec = 0; 1486 atv.tv_usec = 0; 1487 } 1488 1489 timo = 0; 1490 seltdinit(td); 1491 /* 1492 * Iterate until the timeout expires or the socket becomes ready. 1493 */ 1494 for (;;) { 1495 selfdalloc(td, NULL); 1496 error = sopoll(so, events, NULL, td); 1497 /* error here is actually the ready events. */ 1498 if (error) 1499 return (0); 1500 if (atv.tv_sec || atv.tv_usec) { 1501 getmicrouptime(&rtv); 1502 if (timevalcmp(&rtv, &atv, >=)) { 1503 seltdclear(td); 1504 return (EWOULDBLOCK); 1505 } 1506 ttv = atv; 1507 timevalsub(&ttv, &rtv); 1508 timo = ttv.tv_sec > 24 * 60 * 60 ? 1509 24 * 60 * 60 * hz : tvtohz(&ttv); 1510 } 1511 error = seltdwait(td, timo); 1512 seltdclear(td); 1513 if (error) 1514 break; 1515 } 1516 /* XXX Duplicates ncp/smb behavior. */ 1517 if (error == ERESTART) 1518 error = 0; 1519 return (error); 1520 } 1521 1522 /* 1523 * Preallocate two selfds associated with 'cookie'. Some fo_poll routines 1524 * have two select sets, one for read and another for write. 1525 */ 1526 static void 1527 selfdalloc(struct thread *td, void *cookie) 1528 { 1529 struct seltd *stp; 1530 1531 stp = td->td_sel; 1532 if (stp->st_free1 == NULL) 1533 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO); 1534 stp->st_free1->sf_td = stp; 1535 stp->st_free1->sf_cookie = cookie; 1536 if (stp->st_free2 == NULL) 1537 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO); 1538 stp->st_free2->sf_td = stp; 1539 stp->st_free2->sf_cookie = cookie; 1540 } 1541 1542 static void 1543 selfdfree(struct seltd *stp, struct selfd *sfp) 1544 { 1545 STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link); 1546 mtx_lock(sfp->sf_mtx); 1547 if (sfp->sf_si) 1548 TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads); 1549 mtx_unlock(sfp->sf_mtx); 1550 uma_zfree(selfd_zone, sfp); 1551 } 1552 1553 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */ 1554 void 1555 seldrain(sip) 1556 struct selinfo *sip; 1557 { 1558 1559 /* 1560 * This feature is already provided by doselwakeup(), thus it is 1561 * enough to go for it. 1562 * Eventually, the context, should take care to avoid races 1563 * between thread calling select()/poll() and file descriptor 1564 * detaching, but, again, the races are just the same as 1565 * selwakeup(). 1566 */ 1567 doselwakeup(sip, -1); 1568 } 1569 1570 /* 1571 * Record a select request. 1572 */ 1573 void 1574 selrecord(selector, sip) 1575 struct thread *selector; 1576 struct selinfo *sip; 1577 { 1578 struct selfd *sfp; 1579 struct seltd *stp; 1580 struct mtx *mtxp; 1581 1582 stp = selector->td_sel; 1583 /* 1584 * Don't record when doing a rescan. 1585 */ 1586 if (stp->st_flags & SELTD_RESCAN) 1587 return; 1588 /* 1589 * Grab one of the preallocated descriptors. 1590 */ 1591 sfp = NULL; 1592 if ((sfp = stp->st_free1) != NULL) 1593 stp->st_free1 = NULL; 1594 else if ((sfp = stp->st_free2) != NULL) 1595 stp->st_free2 = NULL; 1596 else 1597 panic("selrecord: No free selfd on selq"); 1598 mtxp = sip->si_mtx; 1599 if (mtxp == NULL) 1600 mtxp = mtx_pool_find(mtxpool_select, sip); 1601 /* 1602 * Initialize the sfp and queue it in the thread. 1603 */ 1604 sfp->sf_si = sip; 1605 sfp->sf_mtx = mtxp; 1606 STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link); 1607 /* 1608 * Now that we've locked the sip, check for initialization. 1609 */ 1610 mtx_lock(mtxp); 1611 if (sip->si_mtx == NULL) { 1612 sip->si_mtx = mtxp; 1613 TAILQ_INIT(&sip->si_tdlist); 1614 } 1615 /* 1616 * Add this thread to the list of selfds listening on this selinfo. 1617 */ 1618 TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads); 1619 mtx_unlock(sip->si_mtx); 1620 } 1621 1622 /* Wake up a selecting thread. */ 1623 void 1624 selwakeup(sip) 1625 struct selinfo *sip; 1626 { 1627 doselwakeup(sip, -1); 1628 } 1629 1630 /* Wake up a selecting thread, and set its priority. */ 1631 void 1632 selwakeuppri(sip, pri) 1633 struct selinfo *sip; 1634 int pri; 1635 { 1636 doselwakeup(sip, pri); 1637 } 1638 1639 /* 1640 * Do a wakeup when a selectable event occurs. 1641 */ 1642 static void 1643 doselwakeup(sip, pri) 1644 struct selinfo *sip; 1645 int pri; 1646 { 1647 struct selfd *sfp; 1648 struct selfd *sfn; 1649 struct seltd *stp; 1650 1651 /* If it's not initialized there can't be any waiters. */ 1652 if (sip->si_mtx == NULL) 1653 return; 1654 /* 1655 * Locking the selinfo locks all selfds associated with it. 1656 */ 1657 mtx_lock(sip->si_mtx); 1658 TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) { 1659 /* 1660 * Once we remove this sfp from the list and clear the 1661 * sf_si seltdclear will know to ignore this si. 1662 */ 1663 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads); 1664 sfp->sf_si = NULL; 1665 stp = sfp->sf_td; 1666 mtx_lock(&stp->st_mtx); 1667 stp->st_flags |= SELTD_PENDING; 1668 cv_broadcastpri(&stp->st_wait, pri); 1669 mtx_unlock(&stp->st_mtx); 1670 } 1671 mtx_unlock(sip->si_mtx); 1672 } 1673 1674 static void 1675 seltdinit(struct thread *td) 1676 { 1677 struct seltd *stp; 1678 1679 if ((stp = td->td_sel) != NULL) 1680 goto out; 1681 td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO); 1682 mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF); 1683 cv_init(&stp->st_wait, "select"); 1684 out: 1685 stp->st_flags = 0; 1686 STAILQ_INIT(&stp->st_selq); 1687 } 1688 1689 static int 1690 seltdwait(struct thread *td, int timo) 1691 { 1692 struct seltd *stp; 1693 int error; 1694 1695 stp = td->td_sel; 1696 /* 1697 * An event of interest may occur while we do not hold the seltd 1698 * locked so check the pending flag before we sleep. 1699 */ 1700 mtx_lock(&stp->st_mtx); 1701 /* 1702 * Any further calls to selrecord will be a rescan. 1703 */ 1704 stp->st_flags |= SELTD_RESCAN; 1705 if (stp->st_flags & SELTD_PENDING) { 1706 mtx_unlock(&stp->st_mtx); 1707 return (0); 1708 } 1709 if (timo > 0) 1710 error = cv_timedwait_sig(&stp->st_wait, &stp->st_mtx, timo); 1711 else 1712 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx); 1713 mtx_unlock(&stp->st_mtx); 1714 1715 return (error); 1716 } 1717 1718 void 1719 seltdfini(struct thread *td) 1720 { 1721 struct seltd *stp; 1722 1723 stp = td->td_sel; 1724 if (stp == NULL) 1725 return; 1726 if (stp->st_free1) 1727 uma_zfree(selfd_zone, stp->st_free1); 1728 if (stp->st_free2) 1729 uma_zfree(selfd_zone, stp->st_free2); 1730 td->td_sel = NULL; 1731 free(stp, M_SELECT); 1732 } 1733 1734 /* 1735 * Remove the references to the thread from all of the objects we were 1736 * polling. 1737 */ 1738 static void 1739 seltdclear(struct thread *td) 1740 { 1741 struct seltd *stp; 1742 struct selfd *sfp; 1743 struct selfd *sfn; 1744 1745 stp = td->td_sel; 1746 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) 1747 selfdfree(stp, sfp); 1748 stp->st_flags = 0; 1749 } 1750 1751 static void selectinit(void *); 1752 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL); 1753 static void 1754 selectinit(void *dummy __unused) 1755 { 1756 1757 selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL, 1758 NULL, NULL, UMA_ALIGN_PTR, 0); 1759 mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF); 1760 }
Cache object: cd6a363a9bfa05d97006c585a9f98dcc
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