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/9.2/sys/kern/sys_generic.c 245103 2013-01-06 15:07:19Z 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 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 (fp->f_vnread_flags & FDEVFS_VNODE) == 0) 541 bwillwrite(); 542 if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) { 543 if (auio->uio_resid != cnt && (error == ERESTART || 544 error == EINTR || error == EWOULDBLOCK)) 545 error = 0; 546 /* Socket layer is responsible for issuing SIGPIPE. */ 547 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) { 548 PROC_LOCK(td->td_proc); 549 tdsignal(td, SIGPIPE); 550 PROC_UNLOCK(td->td_proc); 551 } 552 } 553 cnt -= auio->uio_resid; 554 #ifdef KTRACE 555 if (ktruio != NULL) { 556 ktruio->uio_resid = cnt; 557 ktrgenio(fd, UIO_WRITE, ktruio, error); 558 } 559 #endif 560 td->td_retval[0] = cnt; 561 return (error); 562 } 563 564 /* 565 * Truncate a file given a file descriptor. 566 * 567 * Can't use fget_write() here, since must return EINVAL and not EBADF if the 568 * descriptor isn't writable. 569 */ 570 int 571 kern_ftruncate(td, fd, length) 572 struct thread *td; 573 int fd; 574 off_t length; 575 { 576 struct file *fp; 577 int error; 578 579 AUDIT_ARG_FD(fd); 580 if (length < 0) 581 return (EINVAL); 582 error = fget(td, fd, CAP_FTRUNCATE, &fp); 583 if (error) 584 return (error); 585 AUDIT_ARG_FILE(td->td_proc, fp); 586 if (!(fp->f_flag & FWRITE)) { 587 fdrop(fp, td); 588 return (EINVAL); 589 } 590 error = fo_truncate(fp, length, td->td_ucred, td); 591 fdrop(fp, td); 592 return (error); 593 } 594 595 #ifndef _SYS_SYSPROTO_H_ 596 struct ftruncate_args { 597 int fd; 598 int pad; 599 off_t length; 600 }; 601 #endif 602 int 603 sys_ftruncate(td, uap) 604 struct thread *td; 605 struct ftruncate_args *uap; 606 { 607 608 return (kern_ftruncate(td, uap->fd, uap->length)); 609 } 610 611 #if defined(COMPAT_43) 612 #ifndef _SYS_SYSPROTO_H_ 613 struct oftruncate_args { 614 int fd; 615 long length; 616 }; 617 #endif 618 int 619 oftruncate(td, uap) 620 struct thread *td; 621 struct oftruncate_args *uap; 622 { 623 624 return (kern_ftruncate(td, uap->fd, uap->length)); 625 } 626 #endif /* COMPAT_43 */ 627 628 #ifndef _SYS_SYSPROTO_H_ 629 struct ioctl_args { 630 int fd; 631 u_long com; 632 caddr_t data; 633 }; 634 #endif 635 /* ARGSUSED */ 636 int 637 sys_ioctl(struct thread *td, struct ioctl_args *uap) 638 { 639 u_long com; 640 int arg, error; 641 u_int size; 642 caddr_t data; 643 644 if (uap->com > 0xffffffff) { 645 printf( 646 "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n", 647 td->td_proc->p_pid, td->td_name, uap->com); 648 uap->com &= 0xffffffff; 649 } 650 com = uap->com; 651 652 /* 653 * Interpret high order word to find amount of data to be 654 * copied to/from the user's address space. 655 */ 656 size = IOCPARM_LEN(com); 657 if ((size > IOCPARM_MAX) || 658 ((com & (IOC_VOID | IOC_IN | IOC_OUT)) == 0) || 659 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43) 660 ((com & IOC_OUT) && size == 0) || 661 #else 662 ((com & (IOC_IN | IOC_OUT)) && size == 0) || 663 #endif 664 ((com & IOC_VOID) && size > 0 && size != sizeof(int))) 665 return (ENOTTY); 666 667 if (size > 0) { 668 if (com & IOC_VOID) { 669 /* Integer argument. */ 670 arg = (intptr_t)uap->data; 671 data = (void *)&arg; 672 size = 0; 673 } else 674 data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK); 675 } else 676 data = (void *)&uap->data; 677 if (com & IOC_IN) { 678 error = copyin(uap->data, data, (u_int)size); 679 if (error) { 680 if (size > 0) 681 free(data, M_IOCTLOPS); 682 return (error); 683 } 684 } else if (com & IOC_OUT) { 685 /* 686 * Zero the buffer so the user always 687 * gets back something deterministic. 688 */ 689 bzero(data, size); 690 } 691 692 error = kern_ioctl(td, uap->fd, com, data); 693 694 if (error == 0 && (com & IOC_OUT)) 695 error = copyout(data, uap->data, (u_int)size); 696 697 if (size > 0) 698 free(data, M_IOCTLOPS); 699 return (error); 700 } 701 702 int 703 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data) 704 { 705 struct file *fp; 706 struct filedesc *fdp; 707 int error; 708 int tmp; 709 710 AUDIT_ARG_FD(fd); 711 AUDIT_ARG_CMD(com); 712 if ((error = fget(td, fd, CAP_IOCTL, &fp)) != 0) 713 return (error); 714 if ((fp->f_flag & (FREAD | FWRITE)) == 0) { 715 fdrop(fp, td); 716 return (EBADF); 717 } 718 fdp = td->td_proc->p_fd; 719 switch (com) { 720 case FIONCLEX: 721 FILEDESC_XLOCK(fdp); 722 fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE; 723 FILEDESC_XUNLOCK(fdp); 724 goto out; 725 case FIOCLEX: 726 FILEDESC_XLOCK(fdp); 727 fdp->fd_ofileflags[fd] |= UF_EXCLOSE; 728 FILEDESC_XUNLOCK(fdp); 729 goto out; 730 case FIONBIO: 731 if ((tmp = *(int *)data)) 732 atomic_set_int(&fp->f_flag, FNONBLOCK); 733 else 734 atomic_clear_int(&fp->f_flag, FNONBLOCK); 735 data = (void *)&tmp; 736 break; 737 case FIOASYNC: 738 if ((tmp = *(int *)data)) 739 atomic_set_int(&fp->f_flag, FASYNC); 740 else 741 atomic_clear_int(&fp->f_flag, FASYNC); 742 data = (void *)&tmp; 743 break; 744 } 745 746 error = fo_ioctl(fp, com, data, td->td_ucred, td); 747 out: 748 fdrop(fp, td); 749 return (error); 750 } 751 752 int 753 poll_no_poll(int events) 754 { 755 /* 756 * Return true for read/write. If the user asked for something 757 * special, return POLLNVAL, so that clients have a way of 758 * determining reliably whether or not the extended 759 * functionality is present without hard-coding knowledge 760 * of specific filesystem implementations. 761 */ 762 if (events & ~POLLSTANDARD) 763 return (POLLNVAL); 764 765 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 766 } 767 768 int 769 sys_pselect(struct thread *td, struct pselect_args *uap) 770 { 771 struct timespec ts; 772 struct timeval tv, *tvp; 773 sigset_t set, *uset; 774 int error; 775 776 if (uap->ts != NULL) { 777 error = copyin(uap->ts, &ts, sizeof(ts)); 778 if (error != 0) 779 return (error); 780 TIMESPEC_TO_TIMEVAL(&tv, &ts); 781 tvp = &tv; 782 } else 783 tvp = NULL; 784 if (uap->sm != NULL) { 785 error = copyin(uap->sm, &set, sizeof(set)); 786 if (error != 0) 787 return (error); 788 uset = &set; 789 } else 790 uset = NULL; 791 return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp, 792 uset, NFDBITS)); 793 } 794 795 int 796 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex, 797 struct timeval *tvp, sigset_t *uset, int abi_nfdbits) 798 { 799 int error; 800 801 if (uset != NULL) { 802 error = kern_sigprocmask(td, SIG_SETMASK, uset, 803 &td->td_oldsigmask, 0); 804 if (error != 0) 805 return (error); 806 td->td_pflags |= TDP_OLDMASK; 807 /* 808 * Make sure that ast() is called on return to 809 * usermode and TDP_OLDMASK is cleared, restoring old 810 * sigmask. 811 */ 812 thread_lock(td); 813 td->td_flags |= TDF_ASTPENDING; 814 thread_unlock(td); 815 } 816 error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits); 817 return (error); 818 } 819 820 #ifndef _SYS_SYSPROTO_H_ 821 struct select_args { 822 int nd; 823 fd_set *in, *ou, *ex; 824 struct timeval *tv; 825 }; 826 #endif 827 int 828 sys_select(struct thread *td, struct select_args *uap) 829 { 830 struct timeval tv, *tvp; 831 int error; 832 833 if (uap->tv != NULL) { 834 error = copyin(uap->tv, &tv, sizeof(tv)); 835 if (error) 836 return (error); 837 tvp = &tv; 838 } else 839 tvp = NULL; 840 841 return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp, 842 NFDBITS)); 843 } 844 845 /* 846 * In the unlikely case when user specified n greater then the last 847 * open file descriptor, check that no bits are set after the last 848 * valid fd. We must return EBADF if any is set. 849 * 850 * There are applications that rely on the behaviour. 851 * 852 * nd is fd_lastfile + 1. 853 */ 854 static int 855 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits) 856 { 857 char *addr, *oaddr; 858 int b, i, res; 859 uint8_t bits; 860 861 if (nd >= ndu || fd_in == NULL) 862 return (0); 863 864 oaddr = NULL; 865 bits = 0; /* silence gcc */ 866 for (i = nd; i < ndu; i++) { 867 b = i / NBBY; 868 #if BYTE_ORDER == LITTLE_ENDIAN 869 addr = (char *)fd_in + b; 870 #else 871 addr = (char *)fd_in; 872 if (abi_nfdbits == NFDBITS) { 873 addr += rounddown(b, sizeof(fd_mask)) + 874 sizeof(fd_mask) - 1 - b % sizeof(fd_mask); 875 } else { 876 addr += rounddown(b, sizeof(uint32_t)) + 877 sizeof(uint32_t) - 1 - b % sizeof(uint32_t); 878 } 879 #endif 880 if (addr != oaddr) { 881 res = fubyte(addr); 882 if (res == -1) 883 return (EFAULT); 884 oaddr = addr; 885 bits = res; 886 } 887 if ((bits & (1 << (i % NBBY))) != 0) 888 return (EBADF); 889 } 890 return (0); 891 } 892 893 int 894 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou, 895 fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits) 896 { 897 struct filedesc *fdp; 898 /* 899 * The magic 2048 here is chosen to be just enough for FD_SETSIZE 900 * infds with the new FD_SETSIZE of 1024, and more than enough for 901 * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE 902 * of 256. 903 */ 904 fd_mask s_selbits[howmany(2048, NFDBITS)]; 905 fd_mask *ibits[3], *obits[3], *selbits, *sbp; 906 struct timeval atv, rtv, ttv; 907 int error, lf, ndu, timo; 908 u_int nbufbytes, ncpbytes, ncpubytes, nfdbits; 909 910 if (nd < 0) 911 return (EINVAL); 912 fdp = td->td_proc->p_fd; 913 ndu = nd; 914 lf = fdp->fd_lastfile; 915 if (nd > lf + 1) 916 nd = lf + 1; 917 918 error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits); 919 if (error != 0) 920 return (error); 921 error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits); 922 if (error != 0) 923 return (error); 924 error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits); 925 if (error != 0) 926 return (error); 927 928 /* 929 * Allocate just enough bits for the non-null fd_sets. Use the 930 * preallocated auto buffer if possible. 931 */ 932 nfdbits = roundup(nd, NFDBITS); 933 ncpbytes = nfdbits / NBBY; 934 ncpubytes = roundup(nd, abi_nfdbits) / NBBY; 935 nbufbytes = 0; 936 if (fd_in != NULL) 937 nbufbytes += 2 * ncpbytes; 938 if (fd_ou != NULL) 939 nbufbytes += 2 * ncpbytes; 940 if (fd_ex != NULL) 941 nbufbytes += 2 * ncpbytes; 942 if (nbufbytes <= sizeof s_selbits) 943 selbits = &s_selbits[0]; 944 else 945 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK); 946 947 /* 948 * Assign pointers into the bit buffers and fetch the input bits. 949 * Put the output buffers together so that they can be bzeroed 950 * together. 951 */ 952 sbp = selbits; 953 #define getbits(name, x) \ 954 do { \ 955 if (name == NULL) { \ 956 ibits[x] = NULL; \ 957 obits[x] = NULL; \ 958 } else { \ 959 ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp; \ 960 obits[x] = sbp; \ 961 sbp += ncpbytes / sizeof *sbp; \ 962 error = copyin(name, ibits[x], ncpubytes); \ 963 if (error != 0) \ 964 goto done; \ 965 bzero((char *)ibits[x] + ncpubytes, \ 966 ncpbytes - ncpubytes); \ 967 } \ 968 } while (0) 969 getbits(fd_in, 0); 970 getbits(fd_ou, 1); 971 getbits(fd_ex, 2); 972 #undef getbits 973 974 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__) 975 /* 976 * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS, 977 * we are running under 32-bit emulation. This should be more 978 * generic. 979 */ 980 #define swizzle_fdset(bits) \ 981 if (abi_nfdbits != NFDBITS && bits != NULL) { \ 982 int i; \ 983 for (i = 0; i < ncpbytes / sizeof *sbp; i++) \ 984 bits[i] = (bits[i] >> 32) | (bits[i] << 32); \ 985 } 986 #else 987 #define swizzle_fdset(bits) 988 #endif 989 990 /* Make sure the bit order makes it through an ABI transition */ 991 swizzle_fdset(ibits[0]); 992 swizzle_fdset(ibits[1]); 993 swizzle_fdset(ibits[2]); 994 995 if (nbufbytes != 0) 996 bzero(selbits, nbufbytes / 2); 997 998 if (tvp != NULL) { 999 atv = *tvp; 1000 if (itimerfix(&atv)) { 1001 error = EINVAL; 1002 goto done; 1003 } 1004 getmicrouptime(&rtv); 1005 timevaladd(&atv, &rtv); 1006 } else { 1007 atv.tv_sec = 0; 1008 atv.tv_usec = 0; 1009 } 1010 timo = 0; 1011 seltdinit(td); 1012 /* Iterate until the timeout expires or descriptors become ready. */ 1013 for (;;) { 1014 error = selscan(td, ibits, obits, nd); 1015 if (error || td->td_retval[0] != 0) 1016 break; 1017 if (atv.tv_sec || atv.tv_usec) { 1018 getmicrouptime(&rtv); 1019 if (timevalcmp(&rtv, &atv, >=)) 1020 break; 1021 ttv = atv; 1022 timevalsub(&ttv, &rtv); 1023 timo = ttv.tv_sec > 24 * 60 * 60 ? 1024 24 * 60 * 60 * hz : tvtohz(&ttv); 1025 } 1026 error = seltdwait(td, timo); 1027 if (error) 1028 break; 1029 error = selrescan(td, ibits, obits); 1030 if (error || td->td_retval[0] != 0) 1031 break; 1032 } 1033 seltdclear(td); 1034 1035 done: 1036 /* select is not restarted after signals... */ 1037 if (error == ERESTART) 1038 error = EINTR; 1039 if (error == EWOULDBLOCK) 1040 error = 0; 1041 1042 /* swizzle bit order back, if necessary */ 1043 swizzle_fdset(obits[0]); 1044 swizzle_fdset(obits[1]); 1045 swizzle_fdset(obits[2]); 1046 #undef swizzle_fdset 1047 1048 #define putbits(name, x) \ 1049 if (name && (error2 = copyout(obits[x], name, ncpubytes))) \ 1050 error = error2; 1051 if (error == 0) { 1052 int error2; 1053 1054 putbits(fd_in, 0); 1055 putbits(fd_ou, 1); 1056 putbits(fd_ex, 2); 1057 #undef putbits 1058 } 1059 if (selbits != &s_selbits[0]) 1060 free(selbits, M_SELECT); 1061 1062 return (error); 1063 } 1064 /* 1065 * Convert a select bit set to poll flags. 1066 * 1067 * The backend always returns POLLHUP/POLLERR if appropriate and we 1068 * return this as a set bit in any set. 1069 */ 1070 static int select_flags[3] = { 1071 POLLRDNORM | POLLHUP | POLLERR, 1072 POLLWRNORM | POLLHUP | POLLERR, 1073 POLLRDBAND | POLLERR 1074 }; 1075 1076 /* 1077 * Compute the fo_poll flags required for a fd given by the index and 1078 * bit position in the fd_mask array. 1079 */ 1080 static __inline int 1081 selflags(fd_mask **ibits, int idx, fd_mask bit) 1082 { 1083 int flags; 1084 int msk; 1085 1086 flags = 0; 1087 for (msk = 0; msk < 3; msk++) { 1088 if (ibits[msk] == NULL) 1089 continue; 1090 if ((ibits[msk][idx] & bit) == 0) 1091 continue; 1092 flags |= select_flags[msk]; 1093 } 1094 return (flags); 1095 } 1096 1097 /* 1098 * Set the appropriate output bits given a mask of fired events and the 1099 * input bits originally requested. 1100 */ 1101 static __inline int 1102 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events) 1103 { 1104 int msk; 1105 int n; 1106 1107 n = 0; 1108 for (msk = 0; msk < 3; msk++) { 1109 if ((events & select_flags[msk]) == 0) 1110 continue; 1111 if (ibits[msk] == NULL) 1112 continue; 1113 if ((ibits[msk][idx] & bit) == 0) 1114 continue; 1115 /* 1116 * XXX Check for a duplicate set. This can occur because a 1117 * socket calls selrecord() twice for each poll() call 1118 * resulting in two selfds per real fd. selrescan() will 1119 * call selsetbits twice as a result. 1120 */ 1121 if ((obits[msk][idx] & bit) != 0) 1122 continue; 1123 obits[msk][idx] |= bit; 1124 n++; 1125 } 1126 1127 return (n); 1128 } 1129 1130 static __inline int 1131 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp) 1132 { 1133 struct file *fp; 1134 #ifdef CAPABILITIES 1135 struct file *fp_fromcap; 1136 int error; 1137 #endif 1138 1139 if ((fp = fget_unlocked(fdp, fd)) == NULL) 1140 return (EBADF); 1141 #ifdef CAPABILITIES 1142 /* 1143 * If the file descriptor is for a capability, test rights and use 1144 * the file descriptor references by the capability. 1145 */ 1146 error = cap_funwrap(fp, CAP_POLL_EVENT, &fp_fromcap); 1147 if (error) { 1148 fdrop(fp, curthread); 1149 return (error); 1150 } 1151 if (fp != fp_fromcap) { 1152 fhold(fp_fromcap); 1153 fdrop(fp, curthread); 1154 fp = fp_fromcap; 1155 } 1156 #endif /* CAPABILITIES */ 1157 *fpp = fp; 1158 return (0); 1159 } 1160 1161 /* 1162 * Traverse the list of fds attached to this thread's seltd and check for 1163 * completion. 1164 */ 1165 static int 1166 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits) 1167 { 1168 struct filedesc *fdp; 1169 struct selinfo *si; 1170 struct seltd *stp; 1171 struct selfd *sfp; 1172 struct selfd *sfn; 1173 struct file *fp; 1174 fd_mask bit; 1175 int fd, ev, n, idx; 1176 int error; 1177 1178 fdp = td->td_proc->p_fd; 1179 stp = td->td_sel; 1180 n = 0; 1181 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) { 1182 fd = (int)(uintptr_t)sfp->sf_cookie; 1183 si = sfp->sf_si; 1184 selfdfree(stp, sfp); 1185 /* If the selinfo wasn't cleared the event didn't fire. */ 1186 if (si != NULL) 1187 continue; 1188 error = getselfd_cap(fdp, fd, &fp); 1189 if (error) 1190 return (error); 1191 idx = fd / NFDBITS; 1192 bit = (fd_mask)1 << (fd % NFDBITS); 1193 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td); 1194 fdrop(fp, td); 1195 if (ev != 0) 1196 n += selsetbits(ibits, obits, idx, bit, ev); 1197 } 1198 stp->st_flags = 0; 1199 td->td_retval[0] = n; 1200 return (0); 1201 } 1202 1203 /* 1204 * Perform the initial filedescriptor scan and register ourselves with 1205 * each selinfo. 1206 */ 1207 static int 1208 selscan(td, ibits, obits, nfd) 1209 struct thread *td; 1210 fd_mask **ibits, **obits; 1211 int nfd; 1212 { 1213 struct filedesc *fdp; 1214 struct file *fp; 1215 fd_mask bit; 1216 int ev, flags, end, fd; 1217 int n, idx; 1218 int error; 1219 1220 fdp = td->td_proc->p_fd; 1221 n = 0; 1222 for (idx = 0, fd = 0; fd < nfd; idx++) { 1223 end = imin(fd + NFDBITS, nfd); 1224 for (bit = 1; fd < end; bit <<= 1, fd++) { 1225 /* Compute the list of events we're interested in. */ 1226 flags = selflags(ibits, idx, bit); 1227 if (flags == 0) 1228 continue; 1229 error = getselfd_cap(fdp, fd, &fp); 1230 if (error) 1231 return (error); 1232 selfdalloc(td, (void *)(uintptr_t)fd); 1233 ev = fo_poll(fp, flags, td->td_ucred, td); 1234 fdrop(fp, td); 1235 if (ev != 0) 1236 n += selsetbits(ibits, obits, idx, bit, ev); 1237 } 1238 } 1239 1240 td->td_retval[0] = n; 1241 return (0); 1242 } 1243 1244 #ifndef _SYS_SYSPROTO_H_ 1245 struct poll_args { 1246 struct pollfd *fds; 1247 u_int nfds; 1248 int timeout; 1249 }; 1250 #endif 1251 int 1252 sys_poll(td, uap) 1253 struct thread *td; 1254 struct poll_args *uap; 1255 { 1256 struct pollfd *bits; 1257 struct pollfd smallbits[32]; 1258 struct timeval atv, rtv, ttv; 1259 int error, timo; 1260 u_int nfds; 1261 size_t ni; 1262 1263 nfds = uap->nfds; 1264 if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 1265 return (EINVAL); 1266 ni = nfds * sizeof(struct pollfd); 1267 if (ni > sizeof(smallbits)) 1268 bits = malloc(ni, M_TEMP, M_WAITOK); 1269 else 1270 bits = smallbits; 1271 error = copyin(uap->fds, bits, ni); 1272 if (error) 1273 goto done; 1274 if (uap->timeout != INFTIM) { 1275 atv.tv_sec = uap->timeout / 1000; 1276 atv.tv_usec = (uap->timeout % 1000) * 1000; 1277 if (itimerfix(&atv)) { 1278 error = EINVAL; 1279 goto done; 1280 } 1281 getmicrouptime(&rtv); 1282 timevaladd(&atv, &rtv); 1283 } else { 1284 atv.tv_sec = 0; 1285 atv.tv_usec = 0; 1286 } 1287 timo = 0; 1288 seltdinit(td); 1289 /* Iterate until the timeout expires or descriptors become ready. */ 1290 for (;;) { 1291 error = pollscan(td, bits, nfds); 1292 if (error || td->td_retval[0] != 0) 1293 break; 1294 if (atv.tv_sec || atv.tv_usec) { 1295 getmicrouptime(&rtv); 1296 if (timevalcmp(&rtv, &atv, >=)) 1297 break; 1298 ttv = atv; 1299 timevalsub(&ttv, &rtv); 1300 timo = ttv.tv_sec > 24 * 60 * 60 ? 1301 24 * 60 * 60 * hz : tvtohz(&ttv); 1302 } 1303 error = seltdwait(td, timo); 1304 if (error) 1305 break; 1306 error = pollrescan(td); 1307 if (error || td->td_retval[0] != 0) 1308 break; 1309 } 1310 seltdclear(td); 1311 1312 done: 1313 /* poll is not restarted after signals... */ 1314 if (error == ERESTART) 1315 error = EINTR; 1316 if (error == EWOULDBLOCK) 1317 error = 0; 1318 if (error == 0) { 1319 error = pollout(td, bits, uap->fds, nfds); 1320 if (error) 1321 goto out; 1322 } 1323 out: 1324 if (ni > sizeof(smallbits)) 1325 free(bits, M_TEMP); 1326 return (error); 1327 } 1328 1329 static int 1330 pollrescan(struct thread *td) 1331 { 1332 struct seltd *stp; 1333 struct selfd *sfp; 1334 struct selfd *sfn; 1335 struct selinfo *si; 1336 struct filedesc *fdp; 1337 struct file *fp; 1338 struct pollfd *fd; 1339 int n; 1340 1341 n = 0; 1342 fdp = td->td_proc->p_fd; 1343 stp = td->td_sel; 1344 FILEDESC_SLOCK(fdp); 1345 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) { 1346 fd = (struct pollfd *)sfp->sf_cookie; 1347 si = sfp->sf_si; 1348 selfdfree(stp, sfp); 1349 /* If the selinfo wasn't cleared the event didn't fire. */ 1350 if (si != NULL) 1351 continue; 1352 fp = fdp->fd_ofiles[fd->fd]; 1353 #ifdef CAPABILITIES 1354 if ((fp == NULL) 1355 || (cap_funwrap(fp, CAP_POLL_EVENT, &fp) != 0)) { 1356 #else 1357 if (fp == NULL) { 1358 #endif 1359 fd->revents = POLLNVAL; 1360 n++; 1361 continue; 1362 } 1363 1364 /* 1365 * Note: backend also returns POLLHUP and 1366 * POLLERR if appropriate. 1367 */ 1368 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td); 1369 if (fd->revents != 0) 1370 n++; 1371 } 1372 FILEDESC_SUNLOCK(fdp); 1373 stp->st_flags = 0; 1374 td->td_retval[0] = n; 1375 return (0); 1376 } 1377 1378 1379 static int 1380 pollout(td, fds, ufds, nfd) 1381 struct thread *td; 1382 struct pollfd *fds; 1383 struct pollfd *ufds; 1384 u_int nfd; 1385 { 1386 int error = 0; 1387 u_int i = 0; 1388 u_int n = 0; 1389 1390 for (i = 0; i < nfd; i++) { 1391 error = copyout(&fds->revents, &ufds->revents, 1392 sizeof(ufds->revents)); 1393 if (error) 1394 return (error); 1395 if (fds->revents != 0) 1396 n++; 1397 fds++; 1398 ufds++; 1399 } 1400 td->td_retval[0] = n; 1401 return (0); 1402 } 1403 1404 static int 1405 pollscan(td, fds, nfd) 1406 struct thread *td; 1407 struct pollfd *fds; 1408 u_int nfd; 1409 { 1410 struct filedesc *fdp = td->td_proc->p_fd; 1411 int i; 1412 struct file *fp; 1413 int n = 0; 1414 1415 FILEDESC_SLOCK(fdp); 1416 for (i = 0; i < nfd; i++, fds++) { 1417 if (fds->fd >= fdp->fd_nfiles) { 1418 fds->revents = POLLNVAL; 1419 n++; 1420 } else if (fds->fd < 0) { 1421 fds->revents = 0; 1422 } else { 1423 fp = fdp->fd_ofiles[fds->fd]; 1424 #ifdef CAPABILITIES 1425 if ((fp == NULL) 1426 || (cap_funwrap(fp, CAP_POLL_EVENT, &fp) != 0)) { 1427 #else 1428 if (fp == NULL) { 1429 #endif 1430 fds->revents = POLLNVAL; 1431 n++; 1432 } else { 1433 /* 1434 * Note: backend also returns POLLHUP and 1435 * POLLERR if appropriate. 1436 */ 1437 selfdalloc(td, fds); 1438 fds->revents = fo_poll(fp, fds->events, 1439 td->td_ucred, td); 1440 /* 1441 * POSIX requires POLLOUT to be never 1442 * set simultaneously with POLLHUP. 1443 */ 1444 if ((fds->revents & POLLHUP) != 0) 1445 fds->revents &= ~POLLOUT; 1446 1447 if (fds->revents != 0) 1448 n++; 1449 } 1450 } 1451 } 1452 FILEDESC_SUNLOCK(fdp); 1453 td->td_retval[0] = n; 1454 return (0); 1455 } 1456 1457 /* 1458 * OpenBSD poll system call. 1459 * 1460 * XXX this isn't quite a true representation.. OpenBSD uses select ops. 1461 */ 1462 #ifndef _SYS_SYSPROTO_H_ 1463 struct openbsd_poll_args { 1464 struct pollfd *fds; 1465 u_int nfds; 1466 int timeout; 1467 }; 1468 #endif 1469 int 1470 sys_openbsd_poll(td, uap) 1471 register struct thread *td; 1472 register struct openbsd_poll_args *uap; 1473 { 1474 return (sys_poll(td, (struct poll_args *)uap)); 1475 } 1476 1477 /* 1478 * XXX This was created specifically to support netncp and netsmb. This 1479 * allows the caller to specify a socket to wait for events on. It returns 1480 * 0 if any events matched and an error otherwise. There is no way to 1481 * determine which events fired. 1482 */ 1483 int 1484 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td) 1485 { 1486 struct timeval atv, rtv, ttv; 1487 int error, timo; 1488 1489 if (tvp != NULL) { 1490 atv = *tvp; 1491 if (itimerfix(&atv)) 1492 return (EINVAL); 1493 getmicrouptime(&rtv); 1494 timevaladd(&atv, &rtv); 1495 } else { 1496 atv.tv_sec = 0; 1497 atv.tv_usec = 0; 1498 } 1499 1500 timo = 0; 1501 seltdinit(td); 1502 /* 1503 * Iterate until the timeout expires or the socket becomes ready. 1504 */ 1505 for (;;) { 1506 selfdalloc(td, NULL); 1507 error = sopoll(so, events, NULL, td); 1508 /* error here is actually the ready events. */ 1509 if (error) 1510 return (0); 1511 if (atv.tv_sec || atv.tv_usec) { 1512 getmicrouptime(&rtv); 1513 if (timevalcmp(&rtv, &atv, >=)) { 1514 seltdclear(td); 1515 return (EWOULDBLOCK); 1516 } 1517 ttv = atv; 1518 timevalsub(&ttv, &rtv); 1519 timo = ttv.tv_sec > 24 * 60 * 60 ? 1520 24 * 60 * 60 * hz : tvtohz(&ttv); 1521 } 1522 error = seltdwait(td, timo); 1523 seltdclear(td); 1524 if (error) 1525 break; 1526 } 1527 /* XXX Duplicates ncp/smb behavior. */ 1528 if (error == ERESTART) 1529 error = 0; 1530 return (error); 1531 } 1532 1533 /* 1534 * Preallocate two selfds associated with 'cookie'. Some fo_poll routines 1535 * have two select sets, one for read and another for write. 1536 */ 1537 static void 1538 selfdalloc(struct thread *td, void *cookie) 1539 { 1540 struct seltd *stp; 1541 1542 stp = td->td_sel; 1543 if (stp->st_free1 == NULL) 1544 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO); 1545 stp->st_free1->sf_td = stp; 1546 stp->st_free1->sf_cookie = cookie; 1547 if (stp->st_free2 == NULL) 1548 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO); 1549 stp->st_free2->sf_td = stp; 1550 stp->st_free2->sf_cookie = cookie; 1551 } 1552 1553 static void 1554 selfdfree(struct seltd *stp, struct selfd *sfp) 1555 { 1556 STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link); 1557 mtx_lock(sfp->sf_mtx); 1558 if (sfp->sf_si) 1559 TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads); 1560 mtx_unlock(sfp->sf_mtx); 1561 uma_zfree(selfd_zone, sfp); 1562 } 1563 1564 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */ 1565 void 1566 seldrain(sip) 1567 struct selinfo *sip; 1568 { 1569 1570 /* 1571 * This feature is already provided by doselwakeup(), thus it is 1572 * enough to go for it. 1573 * Eventually, the context, should take care to avoid races 1574 * between thread calling select()/poll() and file descriptor 1575 * detaching, but, again, the races are just the same as 1576 * selwakeup(). 1577 */ 1578 doselwakeup(sip, -1); 1579 } 1580 1581 /* 1582 * Record a select request. 1583 */ 1584 void 1585 selrecord(selector, sip) 1586 struct thread *selector; 1587 struct selinfo *sip; 1588 { 1589 struct selfd *sfp; 1590 struct seltd *stp; 1591 struct mtx *mtxp; 1592 1593 stp = selector->td_sel; 1594 /* 1595 * Don't record when doing a rescan. 1596 */ 1597 if (stp->st_flags & SELTD_RESCAN) 1598 return; 1599 /* 1600 * Grab one of the preallocated descriptors. 1601 */ 1602 sfp = NULL; 1603 if ((sfp = stp->st_free1) != NULL) 1604 stp->st_free1 = NULL; 1605 else if ((sfp = stp->st_free2) != NULL) 1606 stp->st_free2 = NULL; 1607 else 1608 panic("selrecord: No free selfd on selq"); 1609 mtxp = sip->si_mtx; 1610 if (mtxp == NULL) 1611 mtxp = mtx_pool_find(mtxpool_select, sip); 1612 /* 1613 * Initialize the sfp and queue it in the thread. 1614 */ 1615 sfp->sf_si = sip; 1616 sfp->sf_mtx = mtxp; 1617 STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link); 1618 /* 1619 * Now that we've locked the sip, check for initialization. 1620 */ 1621 mtx_lock(mtxp); 1622 if (sip->si_mtx == NULL) { 1623 sip->si_mtx = mtxp; 1624 TAILQ_INIT(&sip->si_tdlist); 1625 } 1626 /* 1627 * Add this thread to the list of selfds listening on this selinfo. 1628 */ 1629 TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads); 1630 mtx_unlock(sip->si_mtx); 1631 } 1632 1633 /* Wake up a selecting thread. */ 1634 void 1635 selwakeup(sip) 1636 struct selinfo *sip; 1637 { 1638 doselwakeup(sip, -1); 1639 } 1640 1641 /* Wake up a selecting thread, and set its priority. */ 1642 void 1643 selwakeuppri(sip, pri) 1644 struct selinfo *sip; 1645 int pri; 1646 { 1647 doselwakeup(sip, pri); 1648 } 1649 1650 /* 1651 * Do a wakeup when a selectable event occurs. 1652 */ 1653 static void 1654 doselwakeup(sip, pri) 1655 struct selinfo *sip; 1656 int pri; 1657 { 1658 struct selfd *sfp; 1659 struct selfd *sfn; 1660 struct seltd *stp; 1661 1662 /* If it's not initialized there can't be any waiters. */ 1663 if (sip->si_mtx == NULL) 1664 return; 1665 /* 1666 * Locking the selinfo locks all selfds associated with it. 1667 */ 1668 mtx_lock(sip->si_mtx); 1669 TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) { 1670 /* 1671 * Once we remove this sfp from the list and clear the 1672 * sf_si seltdclear will know to ignore this si. 1673 */ 1674 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads); 1675 sfp->sf_si = NULL; 1676 stp = sfp->sf_td; 1677 mtx_lock(&stp->st_mtx); 1678 stp->st_flags |= SELTD_PENDING; 1679 cv_broadcastpri(&stp->st_wait, pri); 1680 mtx_unlock(&stp->st_mtx); 1681 } 1682 mtx_unlock(sip->si_mtx); 1683 } 1684 1685 static void 1686 seltdinit(struct thread *td) 1687 { 1688 struct seltd *stp; 1689 1690 if ((stp = td->td_sel) != NULL) 1691 goto out; 1692 td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO); 1693 mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF); 1694 cv_init(&stp->st_wait, "select"); 1695 out: 1696 stp->st_flags = 0; 1697 STAILQ_INIT(&stp->st_selq); 1698 } 1699 1700 static int 1701 seltdwait(struct thread *td, int timo) 1702 { 1703 struct seltd *stp; 1704 int error; 1705 1706 stp = td->td_sel; 1707 /* 1708 * An event of interest may occur while we do not hold the seltd 1709 * locked so check the pending flag before we sleep. 1710 */ 1711 mtx_lock(&stp->st_mtx); 1712 /* 1713 * Any further calls to selrecord will be a rescan. 1714 */ 1715 stp->st_flags |= SELTD_RESCAN; 1716 if (stp->st_flags & SELTD_PENDING) { 1717 mtx_unlock(&stp->st_mtx); 1718 return (0); 1719 } 1720 if (timo > 0) 1721 error = cv_timedwait_sig(&stp->st_wait, &stp->st_mtx, timo); 1722 else 1723 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx); 1724 mtx_unlock(&stp->st_mtx); 1725 1726 return (error); 1727 } 1728 1729 void 1730 seltdfini(struct thread *td) 1731 { 1732 struct seltd *stp; 1733 1734 stp = td->td_sel; 1735 if (stp == NULL) 1736 return; 1737 if (stp->st_free1) 1738 uma_zfree(selfd_zone, stp->st_free1); 1739 if (stp->st_free2) 1740 uma_zfree(selfd_zone, stp->st_free2); 1741 td->td_sel = NULL; 1742 free(stp, M_SELECT); 1743 } 1744 1745 /* 1746 * Remove the references to the thread from all of the objects we were 1747 * polling. 1748 */ 1749 static void 1750 seltdclear(struct thread *td) 1751 { 1752 struct seltd *stp; 1753 struct selfd *sfp; 1754 struct selfd *sfn; 1755 1756 stp = td->td_sel; 1757 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) 1758 selfdfree(stp, sfp); 1759 stp->st_flags = 0; 1760 } 1761 1762 static void selectinit(void *); 1763 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL); 1764 static void 1765 selectinit(void *dummy __unused) 1766 { 1767 1768 selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL, 1769 NULL, NULL, UMA_ALIGN_PTR, 0); 1770 mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF); 1771 }
Cache object: 2876434d693974659b4a0be77367a077
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