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("$FreeBSD$"); 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 /* 78 * The following macro defines how many bytes will be allocated from 79 * the stack instead of memory allocated when passing the IOCTL data 80 * structures from userspace and to the kernel. Some IOCTLs having 81 * small data structures are used very frequently and this small 82 * buffer on the stack gives a significant speedup improvement for 83 * those requests. The value of this define should be greater or equal 84 * to 64 bytes and should also be power of two. The data structure is 85 * currently hard-aligned to a 8-byte boundary on the stack. This 86 * should currently be sufficient for all supported platforms. 87 */ 88 #define SYS_IOCTL_SMALL_SIZE 128 /* bytes */ 89 #define SYS_IOCTL_SMALL_ALIGN 8 /* bytes */ 90 91 int iosize_max_clamp = 1; 92 SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW, 93 &iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX"); 94 int devfs_iosize_max_clamp = 1; 95 SYSCTL_INT(_debug, OID_AUTO, devfs_iosize_max_clamp, CTLFLAG_RW, 96 &devfs_iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX for devices"); 97 98 /* 99 * Assert that the return value of read(2) and write(2) syscalls fits 100 * into a register. If not, an architecture will need to provide the 101 * usermode wrappers to reconstruct the result. 102 */ 103 CTASSERT(sizeof(register_t) >= sizeof(size_t)); 104 105 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer"); 106 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer"); 107 MALLOC_DEFINE(M_IOV, "iov", "large iov's"); 108 109 static int pollout(struct thread *, struct pollfd *, struct pollfd *, 110 u_int); 111 static int pollscan(struct thread *, struct pollfd *, u_int); 112 static int pollrescan(struct thread *); 113 static int selscan(struct thread *, fd_mask **, fd_mask **, int); 114 static int selrescan(struct thread *, fd_mask **, fd_mask **); 115 static void selfdalloc(struct thread *, void *); 116 static void selfdfree(struct seltd *, struct selfd *); 117 static int dofileread(struct thread *, int, struct file *, struct uio *, 118 off_t, int); 119 static int dofilewrite(struct thread *, int, struct file *, struct uio *, 120 off_t, int); 121 static void doselwakeup(struct selinfo *, int); 122 static void seltdinit(struct thread *); 123 static int seltdwait(struct thread *, int); 124 static void seltdclear(struct thread *); 125 126 /* 127 * One seltd per-thread allocated on demand as needed. 128 * 129 * t - protected by st_mtx 130 * k - Only accessed by curthread or read-only 131 */ 132 struct seltd { 133 STAILQ_HEAD(, selfd) st_selq; /* (k) List of selfds. */ 134 struct selfd *st_free1; /* (k) free fd for read set. */ 135 struct selfd *st_free2; /* (k) free fd for write set. */ 136 struct mtx st_mtx; /* Protects struct seltd */ 137 struct cv st_wait; /* (t) Wait channel. */ 138 int st_flags; /* (t) SELTD_ flags. */ 139 }; 140 141 #define SELTD_PENDING 0x0001 /* We have pending events. */ 142 #define SELTD_RESCAN 0x0002 /* Doing a rescan. */ 143 144 /* 145 * One selfd allocated per-thread per-file-descriptor. 146 * f - protected by sf_mtx 147 */ 148 struct selfd { 149 STAILQ_ENTRY(selfd) sf_link; /* (k) fds owned by this td. */ 150 TAILQ_ENTRY(selfd) sf_threads; /* (f) fds on this selinfo. */ 151 struct selinfo *sf_si; /* (f) selinfo when linked. */ 152 struct mtx *sf_mtx; /* Pointer to selinfo mtx. */ 153 struct seltd *sf_td; /* (k) owning seltd. */ 154 void *sf_cookie; /* (k) fd or pollfd. */ 155 }; 156 157 static uma_zone_t selfd_zone; 158 static struct mtx_pool *mtxpool_select; 159 160 #ifndef _SYS_SYSPROTO_H_ 161 struct read_args { 162 int fd; 163 void *buf; 164 size_t nbyte; 165 }; 166 #endif 167 int 168 sys_read(td, uap) 169 struct thread *td; 170 struct read_args *uap; 171 { 172 struct uio auio; 173 struct iovec aiov; 174 int error; 175 176 if (uap->nbyte > IOSIZE_MAX) 177 return (EINVAL); 178 aiov.iov_base = uap->buf; 179 aiov.iov_len = uap->nbyte; 180 auio.uio_iov = &aiov; 181 auio.uio_iovcnt = 1; 182 auio.uio_resid = uap->nbyte; 183 auio.uio_segflg = UIO_USERSPACE; 184 error = kern_readv(td, uap->fd, &auio); 185 return(error); 186 } 187 188 /* 189 * Positioned read system call 190 */ 191 #ifndef _SYS_SYSPROTO_H_ 192 struct pread_args { 193 int fd; 194 void *buf; 195 size_t nbyte; 196 int pad; 197 off_t offset; 198 }; 199 #endif 200 int 201 sys_pread(td, uap) 202 struct thread *td; 203 struct pread_args *uap; 204 { 205 struct uio auio; 206 struct iovec aiov; 207 int error; 208 209 if (uap->nbyte > IOSIZE_MAX) 210 return (EINVAL); 211 aiov.iov_base = uap->buf; 212 aiov.iov_len = uap->nbyte; 213 auio.uio_iov = &aiov; 214 auio.uio_iovcnt = 1; 215 auio.uio_resid = uap->nbyte; 216 auio.uio_segflg = UIO_USERSPACE; 217 error = kern_preadv(td, uap->fd, &auio, uap->offset); 218 return(error); 219 } 220 221 int 222 freebsd6_pread(td, uap) 223 struct thread *td; 224 struct freebsd6_pread_args *uap; 225 { 226 struct pread_args oargs; 227 228 oargs.fd = uap->fd; 229 oargs.buf = uap->buf; 230 oargs.nbyte = uap->nbyte; 231 oargs.offset = uap->offset; 232 return (sys_pread(td, &oargs)); 233 } 234 235 /* 236 * Scatter read system call. 237 */ 238 #ifndef _SYS_SYSPROTO_H_ 239 struct readv_args { 240 int fd; 241 struct iovec *iovp; 242 u_int iovcnt; 243 }; 244 #endif 245 int 246 sys_readv(struct thread *td, struct readv_args *uap) 247 { 248 struct uio *auio; 249 int error; 250 251 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 252 if (error) 253 return (error); 254 error = kern_readv(td, uap->fd, auio); 255 free(auio, M_IOV); 256 return (error); 257 } 258 259 int 260 kern_readv(struct thread *td, int fd, struct uio *auio) 261 { 262 struct file *fp; 263 int error; 264 265 error = fget_read(td, fd, CAP_READ | CAP_SEEK, &fp); 266 if (error) 267 return (error); 268 error = dofileread(td, fd, fp, auio, (off_t)-1, 0); 269 fdrop(fp, td); 270 return (error); 271 } 272 273 /* 274 * Scatter positioned read system call. 275 */ 276 #ifndef _SYS_SYSPROTO_H_ 277 struct preadv_args { 278 int fd; 279 struct iovec *iovp; 280 u_int iovcnt; 281 off_t offset; 282 }; 283 #endif 284 int 285 sys_preadv(struct thread *td, struct preadv_args *uap) 286 { 287 struct uio *auio; 288 int error; 289 290 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 291 if (error) 292 return (error); 293 error = kern_preadv(td, uap->fd, auio, uap->offset); 294 free(auio, M_IOV); 295 return (error); 296 } 297 298 int 299 kern_preadv(td, fd, auio, offset) 300 struct thread *td; 301 int fd; 302 struct uio *auio; 303 off_t offset; 304 { 305 struct file *fp; 306 int error; 307 308 error = fget_read(td, fd, CAP_READ, &fp); 309 if (error) 310 return (error); 311 if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE)) 312 error = ESPIPE; 313 else if (offset < 0 && fp->f_vnode->v_type != VCHR) 314 error = EINVAL; 315 else 316 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET); 317 fdrop(fp, td); 318 return (error); 319 } 320 321 /* 322 * Common code for readv and preadv that reads data in 323 * from a file using the passed in uio, offset, and flags. 324 */ 325 static int 326 dofileread(td, fd, fp, auio, offset, flags) 327 struct thread *td; 328 int fd; 329 struct file *fp; 330 struct uio *auio; 331 off_t offset; 332 int flags; 333 { 334 ssize_t cnt; 335 int error; 336 #ifdef KTRACE 337 struct uio *ktruio = NULL; 338 #endif 339 340 /* Finish zero length reads right here */ 341 if (auio->uio_resid == 0) { 342 td->td_retval[0] = 0; 343 return(0); 344 } 345 auio->uio_rw = UIO_READ; 346 auio->uio_offset = offset; 347 auio->uio_td = td; 348 #ifdef KTRACE 349 if (KTRPOINT(td, KTR_GENIO)) 350 ktruio = cloneuio(auio); 351 #endif 352 cnt = auio->uio_resid; 353 if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) { 354 if (auio->uio_resid != cnt && (error == ERESTART || 355 error == EINTR || error == EWOULDBLOCK)) 356 error = 0; 357 } 358 cnt -= auio->uio_resid; 359 #ifdef KTRACE 360 if (ktruio != NULL) { 361 ktruio->uio_resid = cnt; 362 ktrgenio(fd, UIO_READ, ktruio, error); 363 } 364 #endif 365 td->td_retval[0] = cnt; 366 return (error); 367 } 368 369 #ifndef _SYS_SYSPROTO_H_ 370 struct write_args { 371 int fd; 372 const void *buf; 373 size_t nbyte; 374 }; 375 #endif 376 int 377 sys_write(td, uap) 378 struct thread *td; 379 struct write_args *uap; 380 { 381 struct uio auio; 382 struct iovec aiov; 383 int error; 384 385 if (uap->nbyte > IOSIZE_MAX) 386 return (EINVAL); 387 aiov.iov_base = (void *)(uintptr_t)uap->buf; 388 aiov.iov_len = uap->nbyte; 389 auio.uio_iov = &aiov; 390 auio.uio_iovcnt = 1; 391 auio.uio_resid = uap->nbyte; 392 auio.uio_segflg = UIO_USERSPACE; 393 error = kern_writev(td, uap->fd, &auio); 394 return(error); 395 } 396 397 /* 398 * Positioned write system call. 399 */ 400 #ifndef _SYS_SYSPROTO_H_ 401 struct pwrite_args { 402 int fd; 403 const void *buf; 404 size_t nbyte; 405 int pad; 406 off_t offset; 407 }; 408 #endif 409 int 410 sys_pwrite(td, uap) 411 struct thread *td; 412 struct pwrite_args *uap; 413 { 414 struct uio auio; 415 struct iovec aiov; 416 int error; 417 418 if (uap->nbyte > IOSIZE_MAX) 419 return (EINVAL); 420 aiov.iov_base = (void *)(uintptr_t)uap->buf; 421 aiov.iov_len = uap->nbyte; 422 auio.uio_iov = &aiov; 423 auio.uio_iovcnt = 1; 424 auio.uio_resid = uap->nbyte; 425 auio.uio_segflg = UIO_USERSPACE; 426 error = kern_pwritev(td, uap->fd, &auio, uap->offset); 427 return(error); 428 } 429 430 int 431 freebsd6_pwrite(td, uap) 432 struct thread *td; 433 struct freebsd6_pwrite_args *uap; 434 { 435 struct pwrite_args oargs; 436 437 oargs.fd = uap->fd; 438 oargs.buf = uap->buf; 439 oargs.nbyte = uap->nbyte; 440 oargs.offset = uap->offset; 441 return (sys_pwrite(td, &oargs)); 442 } 443 444 /* 445 * Gather write system call. 446 */ 447 #ifndef _SYS_SYSPROTO_H_ 448 struct writev_args { 449 int fd; 450 struct iovec *iovp; 451 u_int iovcnt; 452 }; 453 #endif 454 int 455 sys_writev(struct thread *td, struct writev_args *uap) 456 { 457 struct uio *auio; 458 int error; 459 460 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 461 if (error) 462 return (error); 463 error = kern_writev(td, uap->fd, auio); 464 free(auio, M_IOV); 465 return (error); 466 } 467 468 int 469 kern_writev(struct thread *td, int fd, struct uio *auio) 470 { 471 struct file *fp; 472 int error; 473 474 error = fget_write(td, fd, CAP_WRITE | CAP_SEEK, &fp); 475 if (error) 476 return (error); 477 error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0); 478 fdrop(fp, td); 479 return (error); 480 } 481 482 /* 483 * Gather positioned write system call. 484 */ 485 #ifndef _SYS_SYSPROTO_H_ 486 struct pwritev_args { 487 int fd; 488 struct iovec *iovp; 489 u_int iovcnt; 490 off_t offset; 491 }; 492 #endif 493 int 494 sys_pwritev(struct thread *td, struct pwritev_args *uap) 495 { 496 struct uio *auio; 497 int error; 498 499 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 500 if (error) 501 return (error); 502 error = kern_pwritev(td, uap->fd, auio, uap->offset); 503 free(auio, M_IOV); 504 return (error); 505 } 506 507 int 508 kern_pwritev(td, fd, auio, offset) 509 struct thread *td; 510 struct uio *auio; 511 int fd; 512 off_t offset; 513 { 514 struct file *fp; 515 int error; 516 517 error = fget_write(td, fd, CAP_WRITE, &fp); 518 if (error) 519 return (error); 520 if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE)) 521 error = ESPIPE; 522 else if (offset < 0 && fp->f_vnode->v_type != VCHR) 523 error = EINVAL; 524 else 525 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET); 526 fdrop(fp, td); 527 return (error); 528 } 529 530 /* 531 * Common code for writev and pwritev that writes data to 532 * a file using the passed in uio, offset, and flags. 533 */ 534 static int 535 dofilewrite(td, fd, fp, auio, offset, flags) 536 struct thread *td; 537 int fd; 538 struct file *fp; 539 struct uio *auio; 540 off_t offset; 541 int flags; 542 { 543 ssize_t cnt; 544 int error; 545 #ifdef KTRACE 546 struct uio *ktruio = NULL; 547 #endif 548 549 auio->uio_rw = UIO_WRITE; 550 auio->uio_td = td; 551 auio->uio_offset = offset; 552 #ifdef KTRACE 553 if (KTRPOINT(td, KTR_GENIO)) 554 ktruio = cloneuio(auio); 555 #endif 556 cnt = auio->uio_resid; 557 if (fp->f_type == DTYPE_VNODE && 558 (fp->f_vnread_flags & FDEVFS_VNODE) == 0) 559 bwillwrite(); 560 if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) { 561 if (auio->uio_resid != cnt && (error == ERESTART || 562 error == EINTR || error == EWOULDBLOCK)) 563 error = 0; 564 /* Socket layer is responsible for issuing SIGPIPE. */ 565 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) { 566 PROC_LOCK(td->td_proc); 567 tdsignal(td, SIGPIPE); 568 PROC_UNLOCK(td->td_proc); 569 } 570 } 571 cnt -= auio->uio_resid; 572 #ifdef KTRACE 573 if (ktruio != NULL) { 574 ktruio->uio_resid = cnt; 575 ktrgenio(fd, UIO_WRITE, ktruio, error); 576 } 577 #endif 578 td->td_retval[0] = cnt; 579 return (error); 580 } 581 582 /* 583 * Truncate a file given a file descriptor. 584 * 585 * Can't use fget_write() here, since must return EINVAL and not EBADF if the 586 * descriptor isn't writable. 587 */ 588 int 589 kern_ftruncate(td, fd, length) 590 struct thread *td; 591 int fd; 592 off_t length; 593 { 594 struct file *fp; 595 int error; 596 597 AUDIT_ARG_FD(fd); 598 if (length < 0) 599 return (EINVAL); 600 error = fget(td, fd, CAP_FTRUNCATE, &fp); 601 if (error) 602 return (error); 603 AUDIT_ARG_FILE(td->td_proc, fp); 604 if (!(fp->f_flag & FWRITE)) { 605 fdrop(fp, td); 606 return (EINVAL); 607 } 608 error = fo_truncate(fp, length, td->td_ucred, td); 609 fdrop(fp, td); 610 return (error); 611 } 612 613 #ifndef _SYS_SYSPROTO_H_ 614 struct ftruncate_args { 615 int fd; 616 int pad; 617 off_t length; 618 }; 619 #endif 620 int 621 sys_ftruncate(td, uap) 622 struct thread *td; 623 struct ftruncate_args *uap; 624 { 625 626 return (kern_ftruncate(td, uap->fd, uap->length)); 627 } 628 629 #if defined(COMPAT_43) 630 #ifndef _SYS_SYSPROTO_H_ 631 struct oftruncate_args { 632 int fd; 633 long length; 634 }; 635 #endif 636 int 637 oftruncate(td, uap) 638 struct thread *td; 639 struct oftruncate_args *uap; 640 { 641 642 return (kern_ftruncate(td, uap->fd, uap->length)); 643 } 644 #endif /* COMPAT_43 */ 645 646 #ifndef _SYS_SYSPROTO_H_ 647 struct ioctl_args { 648 int fd; 649 u_long com; 650 caddr_t data; 651 }; 652 #endif 653 /* ARGSUSED */ 654 int 655 sys_ioctl(struct thread *td, struct ioctl_args *uap) 656 { 657 u_char smalldata[SYS_IOCTL_SMALL_SIZE] __aligned(SYS_IOCTL_SMALL_ALIGN); 658 u_long com; 659 int arg, error; 660 u_int size; 661 caddr_t data; 662 663 if (uap->com > 0xffffffff) { 664 printf( 665 "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n", 666 td->td_proc->p_pid, td->td_name, uap->com); 667 uap->com &= 0xffffffff; 668 } 669 com = uap->com; 670 671 /* 672 * Interpret high order word to find amount of data to be 673 * copied to/from the user's address space. 674 */ 675 size = IOCPARM_LEN(com); 676 if ((size > IOCPARM_MAX) || 677 ((com & (IOC_VOID | IOC_IN | IOC_OUT)) == 0) || 678 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43) 679 ((com & IOC_OUT) && size == 0) || 680 #else 681 ((com & (IOC_IN | IOC_OUT)) && size == 0) || 682 #endif 683 ((com & IOC_VOID) && size > 0 && size != sizeof(int))) 684 return (ENOTTY); 685 686 if (size > 0) { 687 if (com & IOC_VOID) { 688 /* Integer argument. */ 689 arg = (intptr_t)uap->data; 690 data = (void *)&arg; 691 size = 0; 692 } else { 693 if (size > SYS_IOCTL_SMALL_SIZE) 694 data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK); 695 else 696 data = smalldata; 697 } 698 } else 699 data = (void *)&uap->data; 700 if (com & IOC_IN) { 701 error = copyin(uap->data, data, (u_int)size); 702 if (error != 0) 703 goto out; 704 } else if (com & IOC_OUT) { 705 /* 706 * Zero the buffer so the user always 707 * gets back something deterministic. 708 */ 709 bzero(data, size); 710 } 711 712 error = kern_ioctl(td, uap->fd, com, data); 713 714 if (error == 0 && (com & IOC_OUT)) 715 error = copyout(data, uap->data, (u_int)size); 716 717 out: 718 if (size > SYS_IOCTL_SMALL_SIZE) 719 free(data, M_IOCTLOPS); 720 return (error); 721 } 722 723 int 724 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data) 725 { 726 struct file *fp; 727 struct filedesc *fdp; 728 int error; 729 int tmp; 730 731 AUDIT_ARG_FD(fd); 732 AUDIT_ARG_CMD(com); 733 if ((error = fget(td, fd, CAP_IOCTL, &fp)) != 0) 734 return (error); 735 if ((fp->f_flag & (FREAD | FWRITE)) == 0) { 736 fdrop(fp, td); 737 return (EBADF); 738 } 739 fdp = td->td_proc->p_fd; 740 switch (com) { 741 case FIONCLEX: 742 FILEDESC_XLOCK(fdp); 743 fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE; 744 FILEDESC_XUNLOCK(fdp); 745 goto out; 746 case FIOCLEX: 747 FILEDESC_XLOCK(fdp); 748 fdp->fd_ofileflags[fd] |= UF_EXCLOSE; 749 FILEDESC_XUNLOCK(fdp); 750 goto out; 751 case FIONBIO: 752 if ((tmp = *(int *)data)) 753 atomic_set_int(&fp->f_flag, FNONBLOCK); 754 else 755 atomic_clear_int(&fp->f_flag, FNONBLOCK); 756 data = (void *)&tmp; 757 break; 758 case FIOASYNC: 759 if ((tmp = *(int *)data)) 760 atomic_set_int(&fp->f_flag, FASYNC); 761 else 762 atomic_clear_int(&fp->f_flag, FASYNC); 763 data = (void *)&tmp; 764 break; 765 } 766 767 error = fo_ioctl(fp, com, data, td->td_ucred, td); 768 out: 769 fdrop(fp, td); 770 return (error); 771 } 772 773 int 774 poll_no_poll(int events) 775 { 776 /* 777 * Return true for read/write. If the user asked for something 778 * special, return POLLNVAL, so that clients have a way of 779 * determining reliably whether or not the extended 780 * functionality is present without hard-coding knowledge 781 * of specific filesystem implementations. 782 */ 783 if (events & ~POLLSTANDARD) 784 return (POLLNVAL); 785 786 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 787 } 788 789 int 790 sys_pselect(struct thread *td, struct pselect_args *uap) 791 { 792 struct timespec ts; 793 struct timeval tv, *tvp; 794 sigset_t set, *uset; 795 int error; 796 797 if (uap->ts != NULL) { 798 error = copyin(uap->ts, &ts, sizeof(ts)); 799 if (error != 0) 800 return (error); 801 TIMESPEC_TO_TIMEVAL(&tv, &ts); 802 tvp = &tv; 803 } else 804 tvp = NULL; 805 if (uap->sm != NULL) { 806 error = copyin(uap->sm, &set, sizeof(set)); 807 if (error != 0) 808 return (error); 809 uset = &set; 810 } else 811 uset = NULL; 812 return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp, 813 uset, NFDBITS)); 814 } 815 816 int 817 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex, 818 struct timeval *tvp, sigset_t *uset, int abi_nfdbits) 819 { 820 int error; 821 822 if (uset != NULL) { 823 error = kern_sigprocmask(td, SIG_SETMASK, uset, 824 &td->td_oldsigmask, 0); 825 if (error != 0) 826 return (error); 827 td->td_pflags |= TDP_OLDMASK; 828 /* 829 * Make sure that ast() is called on return to 830 * usermode and TDP_OLDMASK is cleared, restoring old 831 * sigmask. 832 */ 833 thread_lock(td); 834 td->td_flags |= TDF_ASTPENDING; 835 thread_unlock(td); 836 } 837 error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits); 838 return (error); 839 } 840 841 #ifndef _SYS_SYSPROTO_H_ 842 struct select_args { 843 int nd; 844 fd_set *in, *ou, *ex; 845 struct timeval *tv; 846 }; 847 #endif 848 int 849 sys_select(struct thread *td, struct select_args *uap) 850 { 851 struct timeval tv, *tvp; 852 int error; 853 854 if (uap->tv != NULL) { 855 error = copyin(uap->tv, &tv, sizeof(tv)); 856 if (error) 857 return (error); 858 tvp = &tv; 859 } else 860 tvp = NULL; 861 862 return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp, 863 NFDBITS)); 864 } 865 866 /* 867 * In the unlikely case when user specified n greater then the last 868 * open file descriptor, check that no bits are set after the last 869 * valid fd. We must return EBADF if any is set. 870 * 871 * There are applications that rely on the behaviour. 872 * 873 * nd is fd_lastfile + 1. 874 */ 875 static int 876 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits) 877 { 878 char *addr, *oaddr; 879 int b, i, res; 880 uint8_t bits; 881 882 if (nd >= ndu || fd_in == NULL) 883 return (0); 884 885 oaddr = NULL; 886 bits = 0; /* silence gcc */ 887 for (i = nd; i < ndu; i++) { 888 b = i / NBBY; 889 #if BYTE_ORDER == LITTLE_ENDIAN 890 addr = (char *)fd_in + b; 891 #else 892 addr = (char *)fd_in; 893 if (abi_nfdbits == NFDBITS) { 894 addr += rounddown(b, sizeof(fd_mask)) + 895 sizeof(fd_mask) - 1 - b % sizeof(fd_mask); 896 } else { 897 addr += rounddown(b, sizeof(uint32_t)) + 898 sizeof(uint32_t) - 1 - b % sizeof(uint32_t); 899 } 900 #endif 901 if (addr != oaddr) { 902 res = fubyte(addr); 903 if (res == -1) 904 return (EFAULT); 905 oaddr = addr; 906 bits = res; 907 } 908 if ((bits & (1 << (i % NBBY))) != 0) 909 return (EBADF); 910 } 911 return (0); 912 } 913 914 int 915 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou, 916 fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits) 917 { 918 struct filedesc *fdp; 919 /* 920 * The magic 2048 here is chosen to be just enough for FD_SETSIZE 921 * infds with the new FD_SETSIZE of 1024, and more than enough for 922 * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE 923 * of 256. 924 */ 925 fd_mask s_selbits[howmany(2048, NFDBITS)]; 926 fd_mask *ibits[3], *obits[3], *selbits, *sbp; 927 struct timeval atv, rtv, ttv; 928 int error, lf, ndu, timo; 929 u_int nbufbytes, ncpbytes, ncpubytes, nfdbits; 930 931 if (nd < 0) 932 return (EINVAL); 933 fdp = td->td_proc->p_fd; 934 ndu = nd; 935 lf = fdp->fd_lastfile; 936 if (nd > lf + 1) 937 nd = lf + 1; 938 939 error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits); 940 if (error != 0) 941 return (error); 942 error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits); 943 if (error != 0) 944 return (error); 945 error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits); 946 if (error != 0) 947 return (error); 948 949 /* 950 * Allocate just enough bits for the non-null fd_sets. Use the 951 * preallocated auto buffer if possible. 952 */ 953 nfdbits = roundup(nd, NFDBITS); 954 ncpbytes = nfdbits / NBBY; 955 ncpubytes = roundup(nd, abi_nfdbits) / NBBY; 956 nbufbytes = 0; 957 if (fd_in != NULL) 958 nbufbytes += 2 * ncpbytes; 959 if (fd_ou != NULL) 960 nbufbytes += 2 * ncpbytes; 961 if (fd_ex != NULL) 962 nbufbytes += 2 * ncpbytes; 963 if (nbufbytes <= sizeof s_selbits) 964 selbits = &s_selbits[0]; 965 else 966 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK); 967 968 /* 969 * Assign pointers into the bit buffers and fetch the input bits. 970 * Put the output buffers together so that they can be bzeroed 971 * together. 972 */ 973 sbp = selbits; 974 #define getbits(name, x) \ 975 do { \ 976 if (name == NULL) { \ 977 ibits[x] = NULL; \ 978 obits[x] = NULL; \ 979 } else { \ 980 ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp; \ 981 obits[x] = sbp; \ 982 sbp += ncpbytes / sizeof *sbp; \ 983 error = copyin(name, ibits[x], ncpubytes); \ 984 if (error != 0) \ 985 goto done; \ 986 bzero((char *)ibits[x] + ncpubytes, \ 987 ncpbytes - ncpubytes); \ 988 } \ 989 } while (0) 990 getbits(fd_in, 0); 991 getbits(fd_ou, 1); 992 getbits(fd_ex, 2); 993 #undef getbits 994 995 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__) 996 /* 997 * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS, 998 * we are running under 32-bit emulation. This should be more 999 * generic. 1000 */ 1001 #define swizzle_fdset(bits) \ 1002 if (abi_nfdbits != NFDBITS && bits != NULL) { \ 1003 int i; \ 1004 for (i = 0; i < ncpbytes / sizeof *sbp; i++) \ 1005 bits[i] = (bits[i] >> 32) | (bits[i] << 32); \ 1006 } 1007 #else 1008 #define swizzle_fdset(bits) 1009 #endif 1010 1011 /* Make sure the bit order makes it through an ABI transition */ 1012 swizzle_fdset(ibits[0]); 1013 swizzle_fdset(ibits[1]); 1014 swizzle_fdset(ibits[2]); 1015 1016 if (nbufbytes != 0) 1017 bzero(selbits, nbufbytes / 2); 1018 1019 if (tvp != NULL) { 1020 atv = *tvp; 1021 if (itimerfix(&atv)) { 1022 error = EINVAL; 1023 goto done; 1024 } 1025 getmicrouptime(&rtv); 1026 timevaladd(&atv, &rtv); 1027 } else { 1028 atv.tv_sec = 0; 1029 atv.tv_usec = 0; 1030 } 1031 timo = 0; 1032 seltdinit(td); 1033 /* Iterate until the timeout expires or descriptors become ready. */ 1034 for (;;) { 1035 error = selscan(td, ibits, obits, nd); 1036 if (error || td->td_retval[0] != 0) 1037 break; 1038 if (atv.tv_sec || atv.tv_usec) { 1039 getmicrouptime(&rtv); 1040 if (timevalcmp(&rtv, &atv, >=)) 1041 break; 1042 ttv = atv; 1043 timevalsub(&ttv, &rtv); 1044 timo = ttv.tv_sec > 24 * 60 * 60 ? 1045 24 * 60 * 60 * hz : tvtohz(&ttv); 1046 } 1047 error = seltdwait(td, timo); 1048 if (error) 1049 break; 1050 error = selrescan(td, ibits, obits); 1051 if (error || td->td_retval[0] != 0) 1052 break; 1053 } 1054 seltdclear(td); 1055 1056 done: 1057 /* select is not restarted after signals... */ 1058 if (error == ERESTART) 1059 error = EINTR; 1060 if (error == EWOULDBLOCK) 1061 error = 0; 1062 1063 /* swizzle bit order back, if necessary */ 1064 swizzle_fdset(obits[0]); 1065 swizzle_fdset(obits[1]); 1066 swizzle_fdset(obits[2]); 1067 #undef swizzle_fdset 1068 1069 #define putbits(name, x) \ 1070 if (name && (error2 = copyout(obits[x], name, ncpubytes))) \ 1071 error = error2; 1072 if (error == 0) { 1073 int error2; 1074 1075 putbits(fd_in, 0); 1076 putbits(fd_ou, 1); 1077 putbits(fd_ex, 2); 1078 #undef putbits 1079 } 1080 if (selbits != &s_selbits[0]) 1081 free(selbits, M_SELECT); 1082 1083 return (error); 1084 } 1085 /* 1086 * Convert a select bit set to poll flags. 1087 * 1088 * The backend always returns POLLHUP/POLLERR if appropriate and we 1089 * return this as a set bit in any set. 1090 */ 1091 static int select_flags[3] = { 1092 POLLRDNORM | POLLHUP | POLLERR, 1093 POLLWRNORM | POLLHUP | POLLERR, 1094 POLLRDBAND | POLLERR 1095 }; 1096 1097 /* 1098 * Compute the fo_poll flags required for a fd given by the index and 1099 * bit position in the fd_mask array. 1100 */ 1101 static __inline int 1102 selflags(fd_mask **ibits, int idx, fd_mask bit) 1103 { 1104 int flags; 1105 int msk; 1106 1107 flags = 0; 1108 for (msk = 0; msk < 3; msk++) { 1109 if (ibits[msk] == NULL) 1110 continue; 1111 if ((ibits[msk][idx] & bit) == 0) 1112 continue; 1113 flags |= select_flags[msk]; 1114 } 1115 return (flags); 1116 } 1117 1118 /* 1119 * Set the appropriate output bits given a mask of fired events and the 1120 * input bits originally requested. 1121 */ 1122 static __inline int 1123 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events) 1124 { 1125 int msk; 1126 int n; 1127 1128 n = 0; 1129 for (msk = 0; msk < 3; msk++) { 1130 if ((events & select_flags[msk]) == 0) 1131 continue; 1132 if (ibits[msk] == NULL) 1133 continue; 1134 if ((ibits[msk][idx] & bit) == 0) 1135 continue; 1136 /* 1137 * XXX Check for a duplicate set. This can occur because a 1138 * socket calls selrecord() twice for each poll() call 1139 * resulting in two selfds per real fd. selrescan() will 1140 * call selsetbits twice as a result. 1141 */ 1142 if ((obits[msk][idx] & bit) != 0) 1143 continue; 1144 obits[msk][idx] |= bit; 1145 n++; 1146 } 1147 1148 return (n); 1149 } 1150 1151 static __inline int 1152 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp) 1153 { 1154 struct file *fp; 1155 #ifdef CAPABILITIES 1156 struct file *fp_fromcap; 1157 int error; 1158 #endif 1159 1160 if ((fp = fget_unlocked(fdp, fd)) == NULL) 1161 return (EBADF); 1162 #ifdef CAPABILITIES 1163 /* 1164 * If the file descriptor is for a capability, test rights and use 1165 * the file descriptor references by the capability. 1166 */ 1167 error = cap_funwrap(fp, CAP_POLL_EVENT, &fp_fromcap); 1168 if (error) { 1169 fdrop(fp, curthread); 1170 return (error); 1171 } 1172 if (fp != fp_fromcap) { 1173 fhold(fp_fromcap); 1174 fdrop(fp, curthread); 1175 fp = fp_fromcap; 1176 } 1177 #endif /* CAPABILITIES */ 1178 *fpp = fp; 1179 return (0); 1180 } 1181 1182 /* 1183 * Traverse the list of fds attached to this thread's seltd and check for 1184 * completion. 1185 */ 1186 static int 1187 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits) 1188 { 1189 struct filedesc *fdp; 1190 struct selinfo *si; 1191 struct seltd *stp; 1192 struct selfd *sfp; 1193 struct selfd *sfn; 1194 struct file *fp; 1195 fd_mask bit; 1196 int fd, ev, n, idx; 1197 int error; 1198 1199 fdp = td->td_proc->p_fd; 1200 stp = td->td_sel; 1201 n = 0; 1202 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) { 1203 fd = (int)(uintptr_t)sfp->sf_cookie; 1204 si = sfp->sf_si; 1205 selfdfree(stp, sfp); 1206 /* If the selinfo wasn't cleared the event didn't fire. */ 1207 if (si != NULL) 1208 continue; 1209 error = getselfd_cap(fdp, fd, &fp); 1210 if (error) 1211 return (error); 1212 idx = fd / NFDBITS; 1213 bit = (fd_mask)1 << (fd % NFDBITS); 1214 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td); 1215 fdrop(fp, td); 1216 if (ev != 0) 1217 n += selsetbits(ibits, obits, idx, bit, ev); 1218 } 1219 stp->st_flags = 0; 1220 td->td_retval[0] = n; 1221 return (0); 1222 } 1223 1224 /* 1225 * Perform the initial filedescriptor scan and register ourselves with 1226 * each selinfo. 1227 */ 1228 static int 1229 selscan(td, ibits, obits, nfd) 1230 struct thread *td; 1231 fd_mask **ibits, **obits; 1232 int nfd; 1233 { 1234 struct filedesc *fdp; 1235 struct file *fp; 1236 fd_mask bit; 1237 int ev, flags, end, fd; 1238 int n, idx; 1239 int error; 1240 1241 fdp = td->td_proc->p_fd; 1242 n = 0; 1243 for (idx = 0, fd = 0; fd < nfd; idx++) { 1244 end = imin(fd + NFDBITS, nfd); 1245 for (bit = 1; fd < end; bit <<= 1, fd++) { 1246 /* Compute the list of events we're interested in. */ 1247 flags = selflags(ibits, idx, bit); 1248 if (flags == 0) 1249 continue; 1250 error = getselfd_cap(fdp, fd, &fp); 1251 if (error) 1252 return (error); 1253 selfdalloc(td, (void *)(uintptr_t)fd); 1254 ev = fo_poll(fp, flags, td->td_ucred, td); 1255 fdrop(fp, td); 1256 if (ev != 0) 1257 n += selsetbits(ibits, obits, idx, bit, ev); 1258 } 1259 } 1260 1261 td->td_retval[0] = n; 1262 return (0); 1263 } 1264 1265 #ifndef _SYS_SYSPROTO_H_ 1266 struct poll_args { 1267 struct pollfd *fds; 1268 u_int nfds; 1269 int timeout; 1270 }; 1271 #endif 1272 int 1273 sys_poll(td, uap) 1274 struct thread *td; 1275 struct poll_args *uap; 1276 { 1277 struct pollfd *bits; 1278 struct pollfd smallbits[32]; 1279 struct timeval atv, rtv, ttv; 1280 int error, timo; 1281 u_int nfds; 1282 size_t ni; 1283 1284 nfds = uap->nfds; 1285 if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 1286 return (EINVAL); 1287 ni = nfds * sizeof(struct pollfd); 1288 if (ni > sizeof(smallbits)) 1289 bits = malloc(ni, M_TEMP, M_WAITOK); 1290 else 1291 bits = smallbits; 1292 error = copyin(uap->fds, bits, ni); 1293 if (error) 1294 goto done; 1295 if (uap->timeout != INFTIM) { 1296 atv.tv_sec = uap->timeout / 1000; 1297 atv.tv_usec = (uap->timeout % 1000) * 1000; 1298 if (itimerfix(&atv)) { 1299 error = EINVAL; 1300 goto done; 1301 } 1302 getmicrouptime(&rtv); 1303 timevaladd(&atv, &rtv); 1304 } else { 1305 atv.tv_sec = 0; 1306 atv.tv_usec = 0; 1307 } 1308 timo = 0; 1309 seltdinit(td); 1310 /* Iterate until the timeout expires or descriptors become ready. */ 1311 for (;;) { 1312 error = pollscan(td, bits, nfds); 1313 if (error || td->td_retval[0] != 0) 1314 break; 1315 if (atv.tv_sec || atv.tv_usec) { 1316 getmicrouptime(&rtv); 1317 if (timevalcmp(&rtv, &atv, >=)) 1318 break; 1319 ttv = atv; 1320 timevalsub(&ttv, &rtv); 1321 timo = ttv.tv_sec > 24 * 60 * 60 ? 1322 24 * 60 * 60 * hz : tvtohz(&ttv); 1323 } 1324 error = seltdwait(td, timo); 1325 if (error) 1326 break; 1327 error = pollrescan(td); 1328 if (error || td->td_retval[0] != 0) 1329 break; 1330 } 1331 seltdclear(td); 1332 1333 done: 1334 /* poll is not restarted after signals... */ 1335 if (error == ERESTART) 1336 error = EINTR; 1337 if (error == EWOULDBLOCK) 1338 error = 0; 1339 if (error == 0) { 1340 error = pollout(td, bits, uap->fds, nfds); 1341 if (error) 1342 goto out; 1343 } 1344 out: 1345 if (ni > sizeof(smallbits)) 1346 free(bits, M_TEMP); 1347 return (error); 1348 } 1349 1350 static int 1351 pollrescan(struct thread *td) 1352 { 1353 struct seltd *stp; 1354 struct selfd *sfp; 1355 struct selfd *sfn; 1356 struct selinfo *si; 1357 struct filedesc *fdp; 1358 struct file *fp; 1359 struct pollfd *fd; 1360 int n; 1361 1362 n = 0; 1363 fdp = td->td_proc->p_fd; 1364 stp = td->td_sel; 1365 FILEDESC_SLOCK(fdp); 1366 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) { 1367 fd = (struct pollfd *)sfp->sf_cookie; 1368 si = sfp->sf_si; 1369 selfdfree(stp, sfp); 1370 /* If the selinfo wasn't cleared the event didn't fire. */ 1371 if (si != NULL) 1372 continue; 1373 fp = fdp->fd_ofiles[fd->fd]; 1374 #ifdef CAPABILITIES 1375 if ((fp == NULL) 1376 || (cap_funwrap(fp, CAP_POLL_EVENT, &fp) != 0)) { 1377 #else 1378 if (fp == NULL) { 1379 #endif 1380 fd->revents = POLLNVAL; 1381 n++; 1382 continue; 1383 } 1384 1385 /* 1386 * Note: backend also returns POLLHUP and 1387 * POLLERR if appropriate. 1388 */ 1389 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td); 1390 if (fd->revents != 0) 1391 n++; 1392 } 1393 FILEDESC_SUNLOCK(fdp); 1394 stp->st_flags = 0; 1395 td->td_retval[0] = n; 1396 return (0); 1397 } 1398 1399 1400 static int 1401 pollout(td, fds, ufds, nfd) 1402 struct thread *td; 1403 struct pollfd *fds; 1404 struct pollfd *ufds; 1405 u_int nfd; 1406 { 1407 int error = 0; 1408 u_int i = 0; 1409 u_int n = 0; 1410 1411 for (i = 0; i < nfd; i++) { 1412 error = copyout(&fds->revents, &ufds->revents, 1413 sizeof(ufds->revents)); 1414 if (error) 1415 return (error); 1416 if (fds->revents != 0) 1417 n++; 1418 fds++; 1419 ufds++; 1420 } 1421 td->td_retval[0] = n; 1422 return (0); 1423 } 1424 1425 static int 1426 pollscan(td, fds, nfd) 1427 struct thread *td; 1428 struct pollfd *fds; 1429 u_int nfd; 1430 { 1431 struct filedesc *fdp = td->td_proc->p_fd; 1432 int i; 1433 struct file *fp; 1434 int n = 0; 1435 1436 FILEDESC_SLOCK(fdp); 1437 for (i = 0; i < nfd; i++, fds++) { 1438 if (fds->fd >= fdp->fd_nfiles) { 1439 fds->revents = POLLNVAL; 1440 n++; 1441 } else if (fds->fd < 0) { 1442 fds->revents = 0; 1443 } else { 1444 fp = fdp->fd_ofiles[fds->fd]; 1445 #ifdef CAPABILITIES 1446 if ((fp == NULL) 1447 || (cap_funwrap(fp, CAP_POLL_EVENT, &fp) != 0)) { 1448 #else 1449 if (fp == NULL) { 1450 #endif 1451 fds->revents = POLLNVAL; 1452 n++; 1453 } else { 1454 /* 1455 * Note: backend also returns POLLHUP and 1456 * POLLERR if appropriate. 1457 */ 1458 selfdalloc(td, fds); 1459 fds->revents = fo_poll(fp, fds->events, 1460 td->td_ucred, td); 1461 /* 1462 * POSIX requires POLLOUT to be never 1463 * set simultaneously with POLLHUP. 1464 */ 1465 if ((fds->revents & POLLHUP) != 0) 1466 fds->revents &= ~POLLOUT; 1467 1468 if (fds->revents != 0) 1469 n++; 1470 } 1471 } 1472 } 1473 FILEDESC_SUNLOCK(fdp); 1474 td->td_retval[0] = n; 1475 return (0); 1476 } 1477 1478 /* 1479 * OpenBSD poll system call. 1480 * 1481 * XXX this isn't quite a true representation.. OpenBSD uses select ops. 1482 */ 1483 #ifndef _SYS_SYSPROTO_H_ 1484 struct openbsd_poll_args { 1485 struct pollfd *fds; 1486 u_int nfds; 1487 int timeout; 1488 }; 1489 #endif 1490 int 1491 sys_openbsd_poll(td, uap) 1492 register struct thread *td; 1493 register struct openbsd_poll_args *uap; 1494 { 1495 return (sys_poll(td, (struct poll_args *)uap)); 1496 } 1497 1498 /* 1499 * XXX This was created specifically to support netncp and netsmb. This 1500 * allows the caller to specify a socket to wait for events on. It returns 1501 * 0 if any events matched and an error otherwise. There is no way to 1502 * determine which events fired. 1503 */ 1504 int 1505 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td) 1506 { 1507 struct timeval atv, rtv, ttv; 1508 int error, timo; 1509 1510 if (tvp != NULL) { 1511 atv = *tvp; 1512 if (itimerfix(&atv)) 1513 return (EINVAL); 1514 getmicrouptime(&rtv); 1515 timevaladd(&atv, &rtv); 1516 } else { 1517 atv.tv_sec = 0; 1518 atv.tv_usec = 0; 1519 } 1520 1521 timo = 0; 1522 seltdinit(td); 1523 /* 1524 * Iterate until the timeout expires or the socket becomes ready. 1525 */ 1526 for (;;) { 1527 selfdalloc(td, NULL); 1528 error = sopoll(so, events, NULL, td); 1529 /* error here is actually the ready events. */ 1530 if (error) 1531 return (0); 1532 if (atv.tv_sec || atv.tv_usec) { 1533 getmicrouptime(&rtv); 1534 if (timevalcmp(&rtv, &atv, >=)) { 1535 seltdclear(td); 1536 return (EWOULDBLOCK); 1537 } 1538 ttv = atv; 1539 timevalsub(&ttv, &rtv); 1540 timo = ttv.tv_sec > 24 * 60 * 60 ? 1541 24 * 60 * 60 * hz : tvtohz(&ttv); 1542 } 1543 error = seltdwait(td, timo); 1544 seltdclear(td); 1545 if (error) 1546 break; 1547 } 1548 /* XXX Duplicates ncp/smb behavior. */ 1549 if (error == ERESTART) 1550 error = 0; 1551 return (error); 1552 } 1553 1554 /* 1555 * Preallocate two selfds associated with 'cookie'. Some fo_poll routines 1556 * have two select sets, one for read and another for write. 1557 */ 1558 static void 1559 selfdalloc(struct thread *td, void *cookie) 1560 { 1561 struct seltd *stp; 1562 1563 stp = td->td_sel; 1564 if (stp->st_free1 == NULL) 1565 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO); 1566 stp->st_free1->sf_td = stp; 1567 stp->st_free1->sf_cookie = cookie; 1568 if (stp->st_free2 == NULL) 1569 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO); 1570 stp->st_free2->sf_td = stp; 1571 stp->st_free2->sf_cookie = cookie; 1572 } 1573 1574 static void 1575 selfdfree(struct seltd *stp, struct selfd *sfp) 1576 { 1577 STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link); 1578 mtx_lock(sfp->sf_mtx); 1579 if (sfp->sf_si) 1580 TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads); 1581 mtx_unlock(sfp->sf_mtx); 1582 uma_zfree(selfd_zone, sfp); 1583 } 1584 1585 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */ 1586 void 1587 seldrain(sip) 1588 struct selinfo *sip; 1589 { 1590 1591 /* 1592 * This feature is already provided by doselwakeup(), thus it is 1593 * enough to go for it. 1594 * Eventually, the context, should take care to avoid races 1595 * between thread calling select()/poll() and file descriptor 1596 * detaching, but, again, the races are just the same as 1597 * selwakeup(). 1598 */ 1599 doselwakeup(sip, -1); 1600 } 1601 1602 /* 1603 * Record a select request. 1604 */ 1605 void 1606 selrecord(selector, sip) 1607 struct thread *selector; 1608 struct selinfo *sip; 1609 { 1610 struct selfd *sfp; 1611 struct seltd *stp; 1612 struct mtx *mtxp; 1613 1614 stp = selector->td_sel; 1615 /* 1616 * Don't record when doing a rescan. 1617 */ 1618 if (stp->st_flags & SELTD_RESCAN) 1619 return; 1620 /* 1621 * Grab one of the preallocated descriptors. 1622 */ 1623 sfp = NULL; 1624 if ((sfp = stp->st_free1) != NULL) 1625 stp->st_free1 = NULL; 1626 else if ((sfp = stp->st_free2) != NULL) 1627 stp->st_free2 = NULL; 1628 else 1629 panic("selrecord: No free selfd on selq"); 1630 mtxp = sip->si_mtx; 1631 if (mtxp == NULL) 1632 mtxp = mtx_pool_find(mtxpool_select, sip); 1633 /* 1634 * Initialize the sfp and queue it in the thread. 1635 */ 1636 sfp->sf_si = sip; 1637 sfp->sf_mtx = mtxp; 1638 STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link); 1639 /* 1640 * Now that we've locked the sip, check for initialization. 1641 */ 1642 mtx_lock(mtxp); 1643 if (sip->si_mtx == NULL) { 1644 sip->si_mtx = mtxp; 1645 TAILQ_INIT(&sip->si_tdlist); 1646 } 1647 /* 1648 * Add this thread to the list of selfds listening on this selinfo. 1649 */ 1650 TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads); 1651 mtx_unlock(sip->si_mtx); 1652 } 1653 1654 /* Wake up a selecting thread. */ 1655 void 1656 selwakeup(sip) 1657 struct selinfo *sip; 1658 { 1659 doselwakeup(sip, -1); 1660 } 1661 1662 /* Wake up a selecting thread, and set its priority. */ 1663 void 1664 selwakeuppri(sip, pri) 1665 struct selinfo *sip; 1666 int pri; 1667 { 1668 doselwakeup(sip, pri); 1669 } 1670 1671 /* 1672 * Do a wakeup when a selectable event occurs. 1673 */ 1674 static void 1675 doselwakeup(sip, pri) 1676 struct selinfo *sip; 1677 int pri; 1678 { 1679 struct selfd *sfp; 1680 struct selfd *sfn; 1681 struct seltd *stp; 1682 1683 /* If it's not initialized there can't be any waiters. */ 1684 if (sip->si_mtx == NULL) 1685 return; 1686 /* 1687 * Locking the selinfo locks all selfds associated with it. 1688 */ 1689 mtx_lock(sip->si_mtx); 1690 TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) { 1691 /* 1692 * Once we remove this sfp from the list and clear the 1693 * sf_si seltdclear will know to ignore this si. 1694 */ 1695 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads); 1696 sfp->sf_si = NULL; 1697 stp = sfp->sf_td; 1698 mtx_lock(&stp->st_mtx); 1699 stp->st_flags |= SELTD_PENDING; 1700 cv_broadcastpri(&stp->st_wait, pri); 1701 mtx_unlock(&stp->st_mtx); 1702 } 1703 mtx_unlock(sip->si_mtx); 1704 } 1705 1706 static void 1707 seltdinit(struct thread *td) 1708 { 1709 struct seltd *stp; 1710 1711 if ((stp = td->td_sel) != NULL) 1712 goto out; 1713 td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO); 1714 mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF); 1715 cv_init(&stp->st_wait, "select"); 1716 out: 1717 stp->st_flags = 0; 1718 STAILQ_INIT(&stp->st_selq); 1719 } 1720 1721 static int 1722 seltdwait(struct thread *td, int timo) 1723 { 1724 struct seltd *stp; 1725 int error; 1726 1727 stp = td->td_sel; 1728 /* 1729 * An event of interest may occur while we do not hold the seltd 1730 * locked so check the pending flag before we sleep. 1731 */ 1732 mtx_lock(&stp->st_mtx); 1733 /* 1734 * Any further calls to selrecord will be a rescan. 1735 */ 1736 stp->st_flags |= SELTD_RESCAN; 1737 if (stp->st_flags & SELTD_PENDING) { 1738 mtx_unlock(&stp->st_mtx); 1739 return (0); 1740 } 1741 if (timo > 0) 1742 error = cv_timedwait_sig(&stp->st_wait, &stp->st_mtx, timo); 1743 else 1744 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx); 1745 mtx_unlock(&stp->st_mtx); 1746 1747 return (error); 1748 } 1749 1750 void 1751 seltdfini(struct thread *td) 1752 { 1753 struct seltd *stp; 1754 1755 stp = td->td_sel; 1756 if (stp == NULL) 1757 return; 1758 if (stp->st_free1) 1759 uma_zfree(selfd_zone, stp->st_free1); 1760 if (stp->st_free2) 1761 uma_zfree(selfd_zone, stp->st_free2); 1762 td->td_sel = NULL; 1763 free(stp, M_SELECT); 1764 } 1765 1766 /* 1767 * Remove the references to the thread from all of the objects we were 1768 * polling. 1769 */ 1770 static void 1771 seltdclear(struct thread *td) 1772 { 1773 struct seltd *stp; 1774 struct selfd *sfp; 1775 struct selfd *sfn; 1776 1777 stp = td->td_sel; 1778 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) 1779 selfdfree(stp, sfp); 1780 stp->st_flags = 0; 1781 } 1782 1783 static void selectinit(void *); 1784 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL); 1785 static void 1786 selectinit(void *dummy __unused) 1787 { 1788 1789 selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL, 1790 NULL, NULL, UMA_ALIGN_PTR, 0); 1791 mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF); 1792 }
Cache object: bc4ce937c4ddb0bccc79418e95ddf129
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