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_ktrace.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/sysproto.h> 45 #include <sys/filedesc.h> 46 #include <sys/filio.h> 47 #include <sys/fcntl.h> 48 #include <sys/file.h> 49 #include <sys/proc.h> 50 #include <sys/signalvar.h> 51 #include <sys/socketvar.h> 52 #include <sys/uio.h> 53 #include <sys/kernel.h> 54 #include <sys/limits.h> 55 #include <sys/malloc.h> 56 #include <sys/poll.h> 57 #include <sys/resourcevar.h> 58 #include <sys/selinfo.h> 59 #include <sys/sleepqueue.h> 60 #include <sys/syscallsubr.h> 61 #include <sys/sysctl.h> 62 #include <sys/sysent.h> 63 #include <sys/vnode.h> 64 #include <sys/bio.h> 65 #include <sys/buf.h> 66 #include <sys/condvar.h> 67 #ifdef KTRACE 68 #include <sys/ktrace.h> 69 #endif 70 #include <vm/vm.h> 71 #include <vm/vm_page.h> 72 73 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer"); 74 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer"); 75 MALLOC_DEFINE(M_IOV, "iov", "large iov's"); 76 77 static int pollscan(struct thread *, struct pollfd *, u_int); 78 static int selscan(struct thread *, fd_mask **, fd_mask **, int); 79 static int dofileread(struct thread *, struct file *, int, void *, 80 size_t, off_t, int); 81 static int dofilewrite(struct thread *, struct file *, int, 82 const void *, size_t, off_t, int); 83 static void doselwakeup(struct selinfo *, int); 84 85 /* 86 * Read system call. 87 */ 88 #ifndef _SYS_SYSPROTO_H_ 89 struct read_args { 90 int fd; 91 void *buf; 92 size_t nbyte; 93 }; 94 #endif 95 /* 96 * MPSAFE 97 */ 98 int 99 read(td, uap) 100 struct thread *td; 101 struct read_args *uap; 102 { 103 struct file *fp; 104 int error; 105 106 if ((error = fget_read(td, uap->fd, &fp)) == 0) { 107 error = dofileread(td, fp, uap->fd, uap->buf, 108 uap->nbyte, (off_t)-1, 0); 109 fdrop(fp, td); 110 } 111 return(error); 112 } 113 114 /* 115 * Pread system call 116 */ 117 #ifndef _SYS_SYSPROTO_H_ 118 struct pread_args { 119 int fd; 120 void *buf; 121 size_t nbyte; 122 int pad; 123 off_t offset; 124 }; 125 #endif 126 /* 127 * MPSAFE 128 */ 129 int 130 pread(td, uap) 131 struct thread *td; 132 struct pread_args *uap; 133 { 134 struct file *fp; 135 int error; 136 137 if ((error = fget_read(td, uap->fd, &fp)) != 0) 138 return (error); 139 if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE)) 140 error = ESPIPE; 141 else if (uap->offset < 0 && fp->f_vnode->v_type != VCHR) 142 error = EINVAL; 143 else { 144 error = dofileread(td, fp, uap->fd, uap->buf, uap->nbyte, 145 uap->offset, FOF_OFFSET); 146 } 147 fdrop(fp, td); 148 return(error); 149 } 150 151 /* 152 * Code common for read and pread 153 */ 154 static int 155 dofileread(td, fp, fd, buf, nbyte, offset, flags) 156 struct thread *td; 157 struct file *fp; 158 int fd, flags; 159 void *buf; 160 size_t nbyte; 161 off_t offset; 162 { 163 struct uio auio; 164 struct iovec aiov; 165 long cnt, error = 0; 166 #ifdef KTRACE 167 struct uio *ktruio = NULL; 168 #endif 169 170 aiov.iov_base = buf; 171 aiov.iov_len = nbyte; 172 auio.uio_iov = &aiov; 173 auio.uio_iovcnt = 1; 174 auio.uio_offset = offset; 175 if (nbyte > INT_MAX) 176 return (EINVAL); 177 auio.uio_resid = nbyte; 178 auio.uio_rw = UIO_READ; 179 auio.uio_segflg = UIO_USERSPACE; 180 auio.uio_td = td; 181 #ifdef KTRACE 182 if (KTRPOINT(td, KTR_GENIO)) 183 ktruio = cloneuio(&auio); 184 #endif 185 cnt = nbyte; 186 187 if ((error = fo_read(fp, &auio, td->td_ucred, flags, td))) { 188 if (auio.uio_resid != cnt && (error == ERESTART || 189 error == EINTR || error == EWOULDBLOCK)) 190 error = 0; 191 } 192 cnt -= auio.uio_resid; 193 #ifdef KTRACE 194 if (ktruio != NULL) { 195 ktruio->uio_resid = cnt; 196 ktrgenio(fd, UIO_READ, ktruio, error); 197 } 198 #endif 199 td->td_retval[0] = cnt; 200 return (error); 201 } 202 203 /* 204 * Scatter read system call. 205 */ 206 #ifndef _SYS_SYSPROTO_H_ 207 struct readv_args { 208 int fd; 209 struct iovec *iovp; 210 u_int iovcnt; 211 }; 212 #endif 213 /* 214 * MPSAFE 215 */ 216 int 217 readv(struct thread *td, struct readv_args *uap) 218 { 219 struct file *fp; 220 struct uio *auio = NULL; 221 long cnt; 222 int error; 223 #ifdef KTRACE 224 struct uio *ktruio = NULL; 225 #endif 226 227 error = fget_read(td, uap->fd, &fp); 228 if (error) 229 return (error); 230 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 231 if (error) { 232 fdrop(fp, td); 233 return (error); 234 } 235 auio->uio_rw = UIO_READ; 236 auio->uio_td = td; 237 #ifdef KTRACE 238 if (KTRPOINT(td, KTR_GENIO)) 239 ktruio = cloneuio(auio); 240 #endif 241 cnt = auio->uio_resid; 242 if ((error = fo_read(fp, auio, td->td_ucred, 0, td))) { 243 if (auio->uio_resid != cnt && (error == ERESTART || 244 error == EINTR || error == EWOULDBLOCK)) 245 error = 0; 246 } 247 cnt -= auio->uio_resid; 248 #ifdef KTRACE 249 if (ktruio != NULL) { 250 ktruio->uio_resid = cnt; 251 ktrgenio(uap->fd, UIO_READ, ktruio, error); 252 } 253 #endif 254 td->td_retval[0] = cnt; 255 free(auio, M_IOV); 256 fdrop(fp, td); 257 return (error); 258 } 259 260 /* 261 * Write system call 262 */ 263 #ifndef _SYS_SYSPROTO_H_ 264 struct write_args { 265 int fd; 266 const void *buf; 267 size_t nbyte; 268 }; 269 #endif 270 /* 271 * MPSAFE 272 */ 273 int 274 write(td, uap) 275 struct thread *td; 276 struct write_args *uap; 277 { 278 struct file *fp; 279 int error; 280 281 if ((error = fget_write(td, uap->fd, &fp)) == 0) { 282 error = dofilewrite(td, fp, uap->fd, uap->buf, uap->nbyte, 283 (off_t)-1, 0); 284 fdrop(fp, td); 285 } else { 286 error = EBADF; /* XXX this can't be right */ 287 } 288 return(error); 289 } 290 291 /* 292 * Pwrite system call 293 */ 294 #ifndef _SYS_SYSPROTO_H_ 295 struct pwrite_args { 296 int fd; 297 const void *buf; 298 size_t nbyte; 299 int pad; 300 off_t offset; 301 }; 302 #endif 303 /* 304 * MPSAFE 305 */ 306 int 307 pwrite(td, uap) 308 struct thread *td; 309 struct pwrite_args *uap; 310 { 311 struct file *fp; 312 int error; 313 314 if ((error = fget_write(td, uap->fd, &fp)) == 0) { 315 if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE)) 316 error = ESPIPE; 317 else if (uap->offset < 0 && fp->f_vnode->v_type != VCHR) 318 error = EINVAL; 319 else { 320 error = dofilewrite(td, fp, uap->fd, uap->buf, 321 uap->nbyte, uap->offset, FOF_OFFSET); 322 } 323 fdrop(fp, td); 324 } else { 325 error = EBADF; /* this can't be right */ 326 } 327 return(error); 328 } 329 330 static int 331 dofilewrite(td, fp, fd, buf, nbyte, offset, flags) 332 struct thread *td; 333 struct file *fp; 334 int fd, flags; 335 const void *buf; 336 size_t nbyte; 337 off_t offset; 338 { 339 struct uio auio; 340 struct iovec aiov; 341 long cnt, error = 0; 342 #ifdef KTRACE 343 struct uio *ktruio = NULL; 344 #endif 345 346 aiov.iov_base = (void *)(uintptr_t)buf; 347 aiov.iov_len = nbyte; 348 auio.uio_iov = &aiov; 349 auio.uio_iovcnt = 1; 350 auio.uio_offset = offset; 351 if (nbyte > INT_MAX) 352 return (EINVAL); 353 auio.uio_resid = nbyte; 354 auio.uio_rw = UIO_WRITE; 355 auio.uio_segflg = UIO_USERSPACE; 356 auio.uio_td = td; 357 #ifdef KTRACE 358 if (KTRPOINT(td, KTR_GENIO)) 359 ktruio = cloneuio(&auio); 360 #endif 361 cnt = nbyte; 362 if (fp->f_type == DTYPE_VNODE) 363 bwillwrite(); 364 if ((error = fo_write(fp, &auio, td->td_ucred, flags, td))) { 365 if (auio.uio_resid != cnt && (error == ERESTART || 366 error == EINTR || error == EWOULDBLOCK)) 367 error = 0; 368 /* Socket layer is responsible for issuing SIGPIPE. */ 369 if (error == EPIPE && fp->f_type != DTYPE_SOCKET) { 370 PROC_LOCK(td->td_proc); 371 psignal(td->td_proc, SIGPIPE); 372 PROC_UNLOCK(td->td_proc); 373 } 374 } 375 cnt -= auio.uio_resid; 376 #ifdef KTRACE 377 if (ktruio != NULL) { 378 ktruio->uio_resid = cnt; 379 ktrgenio(fd, UIO_WRITE, ktruio, error); 380 } 381 #endif 382 td->td_retval[0] = cnt; 383 return (error); 384 } 385 386 /* 387 * Gather write system call 388 */ 389 #ifndef _SYS_SYSPROTO_H_ 390 struct writev_args { 391 int fd; 392 struct iovec *iovp; 393 u_int iovcnt; 394 }; 395 #endif 396 /* 397 * MPSAFE 398 */ 399 int 400 writev(struct thread *td, struct writev_args *uap) 401 { 402 struct file *fp; 403 struct uio *auio = NULL; 404 long cnt; 405 int error; 406 #ifdef KTRACE 407 struct uio *ktruio = NULL; 408 #endif 409 410 error = fget_write(td, uap->fd, &fp); 411 if (error) 412 return (EBADF); 413 error = copyinuio(uap->iovp, uap->iovcnt, &auio); 414 if (error) { 415 fdrop(fp, td); 416 return (error); 417 } 418 auio->uio_rw = UIO_WRITE; 419 auio->uio_td = td; 420 #ifdef KTRACE 421 if (KTRPOINT(td, KTR_GENIO)) 422 ktruio = cloneuio(auio); 423 #endif 424 cnt = auio->uio_resid; 425 if (fp->f_type == DTYPE_VNODE) 426 bwillwrite(); 427 if ((error = fo_write(fp, auio, td->td_ucred, 0, td))) { 428 if (auio->uio_resid != cnt && (error == ERESTART || 429 error == EINTR || error == EWOULDBLOCK)) 430 error = 0; 431 if (error == EPIPE) { 432 PROC_LOCK(td->td_proc); 433 psignal(td->td_proc, SIGPIPE); 434 PROC_UNLOCK(td->td_proc); 435 } 436 } 437 cnt -= auio->uio_resid; 438 #ifdef KTRACE 439 if (ktruio != NULL) { 440 ktruio->uio_resid = cnt; 441 ktrgenio(uap->fd, UIO_WRITE, ktruio, error); 442 } 443 #endif 444 td->td_retval[0] = cnt; 445 fdrop(fp, td); 446 free(auio, M_IOV); 447 return (error); 448 } 449 450 /* 451 * Ioctl system call 452 */ 453 #ifndef _SYS_SYSPROTO_H_ 454 struct ioctl_args { 455 int fd; 456 u_long com; 457 caddr_t data; 458 }; 459 #endif 460 /* 461 * MPSAFE 462 */ 463 /* ARGSUSED */ 464 int 465 ioctl(struct thread *td, struct ioctl_args *uap) 466 { 467 struct file *fp; 468 struct filedesc *fdp; 469 u_long com; 470 int error = 0; 471 u_int size; 472 caddr_t data, memp; 473 int tmp; 474 475 if (uap->com > 0xffffffff) { 476 printf( 477 "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n", 478 td->td_proc->p_pid, td->td_proc->p_comm, uap->com); 479 uap->com &= 0xffffffff; 480 } 481 if ((error = fget(td, uap->fd, &fp)) != 0) 482 return (error); 483 if ((fp->f_flag & (FREAD | FWRITE)) == 0) { 484 fdrop(fp, td); 485 return (EBADF); 486 } 487 fdp = td->td_proc->p_fd; 488 switch (com = uap->com) { 489 case FIONCLEX: 490 FILEDESC_LOCK_FAST(fdp); 491 fdp->fd_ofileflags[uap->fd] &= ~UF_EXCLOSE; 492 FILEDESC_UNLOCK_FAST(fdp); 493 fdrop(fp, td); 494 return (0); 495 case FIOCLEX: 496 FILEDESC_LOCK_FAST(fdp); 497 fdp->fd_ofileflags[uap->fd] |= UF_EXCLOSE; 498 FILEDESC_UNLOCK_FAST(fdp); 499 fdrop(fp, td); 500 return (0); 501 } 502 503 /* 504 * Interpret high order word to find amount of data to be 505 * copied to/from the user's address space. 506 */ 507 size = IOCPARM_LEN(com); 508 if ((size > IOCPARM_MAX) || 509 ((com & (IOC_VOID | IOC_IN | IOC_OUT)) == 0) || 510 ((com & IOC_VOID) && size > 0) || 511 ((com & (IOC_IN | IOC_OUT)) && size == 0)) { 512 fdrop(fp, td); 513 return (ENOTTY); 514 } 515 516 if (size > 0) { 517 memp = malloc((u_long)size, M_IOCTLOPS, M_WAITOK); 518 data = memp; 519 } else { 520 memp = NULL; 521 data = (void *)&uap->data; 522 } 523 if (com & IOC_IN) { 524 error = copyin(uap->data, data, (u_int)size); 525 if (error) { 526 free(memp, M_IOCTLOPS); 527 fdrop(fp, td); 528 return (error); 529 } 530 } else if (com & IOC_OUT) { 531 /* 532 * Zero the buffer so the user always 533 * gets back something deterministic. 534 */ 535 bzero(data, size); 536 } 537 538 if (com == FIONBIO) { 539 FILE_LOCK(fp); 540 if ((tmp = *(int *)data)) 541 fp->f_flag |= FNONBLOCK; 542 else 543 fp->f_flag &= ~FNONBLOCK; 544 FILE_UNLOCK(fp); 545 data = (void *)&tmp; 546 } else if (com == FIOASYNC) { 547 FILE_LOCK(fp); 548 if ((tmp = *(int *)data)) 549 fp->f_flag |= FASYNC; 550 else 551 fp->f_flag &= ~FASYNC; 552 FILE_UNLOCK(fp); 553 data = (void *)&tmp; 554 } 555 556 error = fo_ioctl(fp, com, data, td->td_ucred, td); 557 558 if (error == 0 && (com & IOC_OUT)) 559 error = copyout(data, uap->data, (u_int)size); 560 561 if (memp != NULL) 562 free(memp, M_IOCTLOPS); 563 fdrop(fp, td); 564 return (error); 565 } 566 567 /* 568 * sellock and selwait are initialized in selectinit() via SYSINIT. 569 */ 570 struct mtx sellock; 571 struct cv selwait; 572 u_int nselcoll; /* Select collisions since boot */ 573 SYSCTL_UINT(_kern, OID_AUTO, nselcoll, CTLFLAG_RD, &nselcoll, 0, ""); 574 575 /* 576 * Select system call. 577 */ 578 #ifndef _SYS_SYSPROTO_H_ 579 struct select_args { 580 int nd; 581 fd_set *in, *ou, *ex; 582 struct timeval *tv; 583 }; 584 #endif 585 /* 586 * MPSAFE 587 */ 588 int 589 select(td, uap) 590 register struct thread *td; 591 register struct select_args *uap; 592 { 593 struct timeval tv, *tvp; 594 int error; 595 596 if (uap->tv != NULL) { 597 error = copyin(uap->tv, &tv, sizeof(tv)); 598 if (error) 599 return (error); 600 tvp = &tv; 601 } else 602 tvp = NULL; 603 604 return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp)); 605 } 606 607 int 608 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou, 609 fd_set *fd_ex, struct timeval *tvp) 610 { 611 struct filedesc *fdp; 612 /* 613 * The magic 2048 here is chosen to be just enough for FD_SETSIZE 614 * infds with the new FD_SETSIZE of 1024, and more than enough for 615 * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE 616 * of 256. 617 */ 618 fd_mask s_selbits[howmany(2048, NFDBITS)]; 619 fd_mask *ibits[3], *obits[3], *selbits, *sbp; 620 struct timeval atv, rtv, ttv; 621 int error, timo; 622 u_int ncoll, nbufbytes, ncpbytes, nfdbits; 623 624 if (nd < 0) 625 return (EINVAL); 626 fdp = td->td_proc->p_fd; 627 628 FILEDESC_LOCK_FAST(fdp); 629 630 if (nd > td->td_proc->p_fd->fd_nfiles) 631 nd = td->td_proc->p_fd->fd_nfiles; /* forgiving; slightly wrong */ 632 FILEDESC_UNLOCK_FAST(fdp); 633 634 /* 635 * Allocate just enough bits for the non-null fd_sets. Use the 636 * preallocated auto buffer if possible. 637 */ 638 nfdbits = roundup(nd, NFDBITS); 639 ncpbytes = nfdbits / NBBY; 640 nbufbytes = 0; 641 if (fd_in != NULL) 642 nbufbytes += 2 * ncpbytes; 643 if (fd_ou != NULL) 644 nbufbytes += 2 * ncpbytes; 645 if (fd_ex != NULL) 646 nbufbytes += 2 * ncpbytes; 647 if (nbufbytes <= sizeof s_selbits) 648 selbits = &s_selbits[0]; 649 else 650 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK); 651 652 /* 653 * Assign pointers into the bit buffers and fetch the input bits. 654 * Put the output buffers together so that they can be bzeroed 655 * together. 656 */ 657 sbp = selbits; 658 #define getbits(name, x) \ 659 do { \ 660 if (name == NULL) \ 661 ibits[x] = NULL; \ 662 else { \ 663 ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp; \ 664 obits[x] = sbp; \ 665 sbp += ncpbytes / sizeof *sbp; \ 666 error = copyin(name, ibits[x], ncpbytes); \ 667 if (error != 0) \ 668 goto done_nosellock; \ 669 } \ 670 } while (0) 671 getbits(fd_in, 0); 672 getbits(fd_ou, 1); 673 getbits(fd_ex, 2); 674 #undef getbits 675 if (nbufbytes != 0) 676 bzero(selbits, nbufbytes / 2); 677 678 if (tvp != NULL) { 679 atv = *tvp; 680 if (itimerfix(&atv)) { 681 error = EINVAL; 682 goto done_nosellock; 683 } 684 getmicrouptime(&rtv); 685 timevaladd(&atv, &rtv); 686 } else { 687 atv.tv_sec = 0; 688 atv.tv_usec = 0; 689 } 690 timo = 0; 691 TAILQ_INIT(&td->td_selq); 692 mtx_lock(&sellock); 693 retry: 694 ncoll = nselcoll; 695 mtx_lock_spin(&sched_lock); 696 td->td_flags |= TDF_SELECT; 697 mtx_unlock_spin(&sched_lock); 698 mtx_unlock(&sellock); 699 700 error = selscan(td, ibits, obits, nd); 701 mtx_lock(&sellock); 702 if (error || td->td_retval[0]) 703 goto done; 704 if (atv.tv_sec || atv.tv_usec) { 705 getmicrouptime(&rtv); 706 if (timevalcmp(&rtv, &atv, >=)) 707 goto done; 708 ttv = atv; 709 timevalsub(&ttv, &rtv); 710 timo = ttv.tv_sec > 24 * 60 * 60 ? 711 24 * 60 * 60 * hz : tvtohz(&ttv); 712 } 713 714 /* 715 * An event of interest may occur while we do not hold 716 * sellock, so check TDF_SELECT and the number of 717 * collisions and rescan the file descriptors if 718 * necessary. 719 */ 720 mtx_lock_spin(&sched_lock); 721 if ((td->td_flags & TDF_SELECT) == 0 || nselcoll != ncoll) { 722 mtx_unlock_spin(&sched_lock); 723 goto retry; 724 } 725 mtx_unlock_spin(&sched_lock); 726 727 if (timo > 0) 728 error = cv_timedwait_sig(&selwait, &sellock, timo); 729 else 730 error = cv_wait_sig(&selwait, &sellock); 731 732 if (error == 0) 733 goto retry; 734 735 done: 736 clear_selinfo_list(td); 737 mtx_lock_spin(&sched_lock); 738 td->td_flags &= ~TDF_SELECT; 739 mtx_unlock_spin(&sched_lock); 740 mtx_unlock(&sellock); 741 742 done_nosellock: 743 /* select is not restarted after signals... */ 744 if (error == ERESTART) 745 error = EINTR; 746 if (error == EWOULDBLOCK) 747 error = 0; 748 #define putbits(name, x) \ 749 if (name && (error2 = copyout(obits[x], name, ncpbytes))) \ 750 error = error2; 751 if (error == 0) { 752 int error2; 753 754 putbits(fd_in, 0); 755 putbits(fd_ou, 1); 756 putbits(fd_ex, 2); 757 #undef putbits 758 } 759 if (selbits != &s_selbits[0]) 760 free(selbits, M_SELECT); 761 762 return (error); 763 } 764 765 static int 766 selscan(td, ibits, obits, nfd) 767 struct thread *td; 768 fd_mask **ibits, **obits; 769 int nfd; 770 { 771 int msk, i, fd; 772 fd_mask bits; 773 struct file *fp; 774 int n = 0; 775 /* Note: backend also returns POLLHUP/POLLERR if appropriate. */ 776 static int flag[3] = { POLLRDNORM, POLLWRNORM, POLLRDBAND }; 777 struct filedesc *fdp = td->td_proc->p_fd; 778 779 FILEDESC_LOCK(fdp); 780 for (msk = 0; msk < 3; msk++) { 781 if (ibits[msk] == NULL) 782 continue; 783 for (i = 0; i < nfd; i += NFDBITS) { 784 bits = ibits[msk][i/NFDBITS]; 785 /* ffs(int mask) not portable, fd_mask is long */ 786 for (fd = i; bits && fd < nfd; fd++, bits >>= 1) { 787 if (!(bits & 1)) 788 continue; 789 if ((fp = fget_locked(fdp, fd)) == NULL) { 790 FILEDESC_UNLOCK(fdp); 791 return (EBADF); 792 } 793 if (fo_poll(fp, flag[msk], td->td_ucred, 794 td)) { 795 obits[msk][(fd)/NFDBITS] |= 796 ((fd_mask)1 << ((fd) % NFDBITS)); 797 n++; 798 } 799 } 800 } 801 } 802 FILEDESC_UNLOCK(fdp); 803 td->td_retval[0] = n; 804 return (0); 805 } 806 807 /* 808 * Poll system call. 809 */ 810 #ifndef _SYS_SYSPROTO_H_ 811 struct poll_args { 812 struct pollfd *fds; 813 u_int nfds; 814 int timeout; 815 }; 816 #endif 817 /* 818 * MPSAFE 819 */ 820 int 821 poll(td, uap) 822 struct thread *td; 823 struct poll_args *uap; 824 { 825 struct pollfd *bits; 826 struct pollfd smallbits[32]; 827 struct timeval atv, rtv, ttv; 828 int error = 0, timo; 829 u_int ncoll, nfds; 830 size_t ni; 831 832 nfds = uap->nfds; 833 834 /* 835 * This is kinda bogus. We have fd limits, but that is not 836 * really related to the size of the pollfd array. Make sure 837 * we let the process use at least FD_SETSIZE entries and at 838 * least enough for the current limits. We want to be reasonably 839 * safe, but not overly restrictive. 840 */ 841 PROC_LOCK(td->td_proc); 842 if ((nfds > lim_cur(td->td_proc, RLIMIT_NOFILE)) && 843 (nfds > FD_SETSIZE)) { 844 PROC_UNLOCK(td->td_proc); 845 error = EINVAL; 846 goto done2; 847 } 848 PROC_UNLOCK(td->td_proc); 849 ni = nfds * sizeof(struct pollfd); 850 if (ni > sizeof(smallbits)) 851 bits = malloc(ni, M_TEMP, M_WAITOK); 852 else 853 bits = smallbits; 854 error = copyin(uap->fds, bits, ni); 855 if (error) 856 goto done_nosellock; 857 if (uap->timeout != INFTIM) { 858 atv.tv_sec = uap->timeout / 1000; 859 atv.tv_usec = (uap->timeout % 1000) * 1000; 860 if (itimerfix(&atv)) { 861 error = EINVAL; 862 goto done_nosellock; 863 } 864 getmicrouptime(&rtv); 865 timevaladd(&atv, &rtv); 866 } else { 867 atv.tv_sec = 0; 868 atv.tv_usec = 0; 869 } 870 timo = 0; 871 TAILQ_INIT(&td->td_selq); 872 mtx_lock(&sellock); 873 retry: 874 ncoll = nselcoll; 875 mtx_lock_spin(&sched_lock); 876 td->td_flags |= TDF_SELECT; 877 mtx_unlock_spin(&sched_lock); 878 mtx_unlock(&sellock); 879 880 error = pollscan(td, bits, nfds); 881 mtx_lock(&sellock); 882 if (error || td->td_retval[0]) 883 goto done; 884 if (atv.tv_sec || atv.tv_usec) { 885 getmicrouptime(&rtv); 886 if (timevalcmp(&rtv, &atv, >=)) 887 goto done; 888 ttv = atv; 889 timevalsub(&ttv, &rtv); 890 timo = ttv.tv_sec > 24 * 60 * 60 ? 891 24 * 60 * 60 * hz : tvtohz(&ttv); 892 } 893 /* 894 * An event of interest may occur while we do not hold 895 * sellock, so check TDF_SELECT and the number of collisions 896 * and rescan the file descriptors if necessary. 897 */ 898 mtx_lock_spin(&sched_lock); 899 if ((td->td_flags & TDF_SELECT) == 0 || nselcoll != ncoll) { 900 mtx_unlock_spin(&sched_lock); 901 goto retry; 902 } 903 mtx_unlock_spin(&sched_lock); 904 905 if (timo > 0) 906 error = cv_timedwait_sig(&selwait, &sellock, timo); 907 else 908 error = cv_wait_sig(&selwait, &sellock); 909 910 if (error == 0) 911 goto retry; 912 913 done: 914 clear_selinfo_list(td); 915 mtx_lock_spin(&sched_lock); 916 td->td_flags &= ~TDF_SELECT; 917 mtx_unlock_spin(&sched_lock); 918 mtx_unlock(&sellock); 919 920 done_nosellock: 921 /* poll is not restarted after signals... */ 922 if (error == ERESTART) 923 error = EINTR; 924 if (error == EWOULDBLOCK) 925 error = 0; 926 if (error == 0) { 927 error = copyout(bits, uap->fds, ni); 928 if (error) 929 goto out; 930 } 931 out: 932 if (ni > sizeof(smallbits)) 933 free(bits, M_TEMP); 934 done2: 935 return (error); 936 } 937 938 static int 939 pollscan(td, fds, nfd) 940 struct thread *td; 941 struct pollfd *fds; 942 u_int nfd; 943 { 944 register struct filedesc *fdp = td->td_proc->p_fd; 945 int i; 946 struct file *fp; 947 int n = 0; 948 949 FILEDESC_LOCK(fdp); 950 for (i = 0; i < nfd; i++, fds++) { 951 if (fds->fd >= fdp->fd_nfiles) { 952 fds->revents = POLLNVAL; 953 n++; 954 } else if (fds->fd < 0) { 955 fds->revents = 0; 956 } else { 957 fp = fdp->fd_ofiles[fds->fd]; 958 if (fp == NULL) { 959 fds->revents = POLLNVAL; 960 n++; 961 } else { 962 /* 963 * Note: backend also returns POLLHUP and 964 * POLLERR if appropriate. 965 */ 966 fds->revents = fo_poll(fp, fds->events, 967 td->td_ucred, td); 968 if (fds->revents != 0) 969 n++; 970 } 971 } 972 } 973 FILEDESC_UNLOCK(fdp); 974 td->td_retval[0] = n; 975 return (0); 976 } 977 978 /* 979 * OpenBSD poll system call. 980 * XXX this isn't quite a true representation.. OpenBSD uses select ops. 981 */ 982 #ifndef _SYS_SYSPROTO_H_ 983 struct openbsd_poll_args { 984 struct pollfd *fds; 985 u_int nfds; 986 int timeout; 987 }; 988 #endif 989 /* 990 * MPSAFE 991 */ 992 int 993 openbsd_poll(td, uap) 994 register struct thread *td; 995 register struct openbsd_poll_args *uap; 996 { 997 return (poll(td, (struct poll_args *)uap)); 998 } 999 1000 /* 1001 * Remove the references to the thread from all of the objects 1002 * we were polling. 1003 * 1004 * This code assumes that the underlying owner of the selinfo 1005 * structure will hold sellock before it changes it, and that 1006 * it will unlink itself from our list if it goes away. 1007 */ 1008 void 1009 clear_selinfo_list(td) 1010 struct thread *td; 1011 { 1012 struct selinfo *si; 1013 1014 mtx_assert(&sellock, MA_OWNED); 1015 TAILQ_FOREACH(si, &td->td_selq, si_thrlist) 1016 si->si_thread = NULL; 1017 TAILQ_INIT(&td->td_selq); 1018 } 1019 1020 /* 1021 * Record a select request. 1022 */ 1023 void 1024 selrecord(selector, sip) 1025 struct thread *selector; 1026 struct selinfo *sip; 1027 { 1028 1029 mtx_lock(&sellock); 1030 /* 1031 * If the selinfo's thread pointer is NULL then take ownership of it. 1032 * 1033 * If the thread pointer is not NULL and it points to another 1034 * thread, then we have a collision. 1035 * 1036 * If the thread pointer is not NULL and points back to us then leave 1037 * it alone as we've already added pointed it at us and added it to 1038 * our list. 1039 */ 1040 if (sip->si_thread == NULL) { 1041 sip->si_thread = selector; 1042 TAILQ_INSERT_TAIL(&selector->td_selq, sip, si_thrlist); 1043 } else if (sip->si_thread != selector) { 1044 sip->si_flags |= SI_COLL; 1045 } 1046 1047 mtx_unlock(&sellock); 1048 } 1049 1050 /* Wake up a selecting thread. */ 1051 void 1052 selwakeup(sip) 1053 struct selinfo *sip; 1054 { 1055 doselwakeup(sip, -1); 1056 } 1057 1058 /* Wake up a selecting thread, and set its priority. */ 1059 void 1060 selwakeuppri(sip, pri) 1061 struct selinfo *sip; 1062 int pri; 1063 { 1064 doselwakeup(sip, pri); 1065 } 1066 1067 /* 1068 * Do a wakeup when a selectable event occurs. 1069 */ 1070 static void 1071 doselwakeup(sip, pri) 1072 struct selinfo *sip; 1073 int pri; 1074 { 1075 struct thread *td; 1076 1077 mtx_lock(&sellock); 1078 td = sip->si_thread; 1079 if ((sip->si_flags & SI_COLL) != 0) { 1080 nselcoll++; 1081 sip->si_flags &= ~SI_COLL; 1082 cv_broadcastpri(&selwait, pri); 1083 } 1084 if (td == NULL) { 1085 mtx_unlock(&sellock); 1086 return; 1087 } 1088 TAILQ_REMOVE(&td->td_selq, sip, si_thrlist); 1089 sip->si_thread = NULL; 1090 mtx_lock_spin(&sched_lock); 1091 td->td_flags &= ~TDF_SELECT; 1092 mtx_unlock_spin(&sched_lock); 1093 sleepq_remove(td, &selwait); 1094 mtx_unlock(&sellock); 1095 } 1096 1097 static void selectinit(void *); 1098 SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, selectinit, NULL) 1099 1100 /* ARGSUSED*/ 1101 static void 1102 selectinit(dummy) 1103 void *dummy; 1104 { 1105 cv_init(&selwait, "select"); 1106 mtx_init(&sellock, "sellck", NULL, MTX_DEF); 1107 } 1108