The Design and Implementation of the FreeBSD Operating System, Second Edition
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: stable/8/sys/kern/sys_generic.c 237486 2012-06-23 17:42:37Z davide $");
   39 
   40 #include "opt_compat.h"
   41 #include "opt_ktrace.h"
   42 
   43 #include <sys/param.h>
   44 #include <sys/systm.h>
   45 #include <sys/sysproto.h>
   46 #include <sys/filedesc.h>
   47 #include <sys/filio.h>
   48 #include <sys/fcntl.h>
   49 #include <sys/file.h>
   50 #include <sys/proc.h>
   51 #include <sys/signalvar.h>
   52 #include <sys/socketvar.h>
   53 #include <sys/uio.h>
   54 #include <sys/kernel.h>
   55 #include <sys/ktr.h>
   56 #include <sys/limits.h>
   57 #include <sys/malloc.h>
   58 #include <sys/poll.h>
   59 #include <sys/resourcevar.h>
   60 #include <sys/selinfo.h>
   61 #include <sys/sleepqueue.h>
   62 #include <sys/syscallsubr.h>
   63 #include <sys/sysctl.h>
   64 #include <sys/sysent.h>
   65 #include <sys/vnode.h>
   66 #include <sys/bio.h>
   67 #include <sys/buf.h>
   68 #include <sys/condvar.h>
   69 #ifdef KTRACE
   70 #include <sys/ktrace.h>
   71 #endif
   72 
   73 #include <security/audit/audit.h>
   74 
   75 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer");
   76 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer");
   77 MALLOC_DEFINE(M_IOV, "iov", "large iov's");
   78 
   79 static int      pollout(struct thread *, struct pollfd *, struct pollfd *,
   80                     u_int);
   81 static int      pollscan(struct thread *, struct pollfd *, u_int);
   82 static int      pollrescan(struct thread *);
   83 static int      selscan(struct thread *, fd_mask **, fd_mask **, int);
   84 static int      selrescan(struct thread *, fd_mask **, fd_mask **);
   85 static void     selfdalloc(struct thread *, void *);
   86 static void     selfdfree(struct seltd *, struct selfd *);
   87 static int      dofileread(struct thread *, int, struct file *, struct uio *,
   88                     off_t, int);
   89 static int      dofilewrite(struct thread *, int, struct file *, struct uio *,
   90                     off_t, int);
   91 static void     doselwakeup(struct selinfo *, int);
   92 static void     seltdinit(struct thread *);
   93 static int      seltdwait(struct thread *, int);
   94 static void     seltdclear(struct thread *);
   95 
   96 /*
   97  * One seltd per-thread allocated on demand as needed.
   98  *
   99  *      t - protected by st_mtx
  100  *      k - Only accessed by curthread or read-only
  101  */
  102 struct seltd {
  103         STAILQ_HEAD(, selfd)    st_selq;        /* (k) List of selfds. */
  104         struct selfd            *st_free1;      /* (k) free fd for read set. */
  105         struct selfd            *st_free2;      /* (k) free fd for write set. */
  106         struct mtx              st_mtx;         /* Protects struct seltd */
  107         struct cv               st_wait;        /* (t) Wait channel. */
  108         int                     st_flags;       /* (t) SELTD_ flags. */
  109 };
  110 
  111 #define SELTD_PENDING   0x0001                  /* We have pending events. */
  112 #define SELTD_RESCAN    0x0002                  /* Doing a rescan. */
  113 
  114 /*
  115  * One selfd allocated per-thread per-file-descriptor.
  116  *      f - protected by sf_mtx
  117  */
  118 struct selfd {
  119         STAILQ_ENTRY(selfd)     sf_link;        /* (k) fds owned by this td. */
  120         TAILQ_ENTRY(selfd)      sf_threads;     /* (f) fds on this selinfo. */
  121         struct selinfo          *sf_si;         /* (f) selinfo when linked. */
  122         struct mtx              *sf_mtx;        /* Pointer to selinfo mtx. */
  123         struct seltd            *sf_td;         /* (k) owning seltd. */
  124         void                    *sf_cookie;     /* (k) fd or pollfd. */
  125 };
  126 
  127 static uma_zone_t selfd_zone;
  128 static struct mtx_pool *mtxpool_select;
  129 
  130 #ifndef _SYS_SYSPROTO_H_
  131 struct read_args {
  132         int     fd;
  133         void    *buf;
  134         size_t  nbyte;
  135 };
  136 #endif
  137 int
  138 read(td, uap)
  139         struct thread *td;
  140         struct read_args *uap;
  141 {
  142         struct uio auio;
  143         struct iovec aiov;
  144         int error;
  145 
  146         if (uap->nbyte > INT_MAX)
  147                 return (EINVAL);
  148         aiov.iov_base = uap->buf;
  149         aiov.iov_len = uap->nbyte;
  150         auio.uio_iov = &aiov;
  151         auio.uio_iovcnt = 1;
  152         auio.uio_resid = uap->nbyte;
  153         auio.uio_segflg = UIO_USERSPACE;
  154         error = kern_readv(td, uap->fd, &auio);
  155         return(error);
  156 }
  157 
  158 /*
  159  * Positioned read system call
  160  */
  161 #ifndef _SYS_SYSPROTO_H_
  162 struct pread_args {
  163         int     fd;
  164         void    *buf;
  165         size_t  nbyte;
  166         int     pad;
  167         off_t   offset;
  168 };
  169 #endif
  170 int
  171 pread(td, uap)
  172         struct thread *td;
  173         struct pread_args *uap;
  174 {
  175         struct uio auio;
  176         struct iovec aiov;
  177         int error;
  178 
  179         if (uap->nbyte > INT_MAX)
  180                 return (EINVAL);
  181         aiov.iov_base = uap->buf;
  182         aiov.iov_len = uap->nbyte;
  183         auio.uio_iov = &aiov;
  184         auio.uio_iovcnt = 1;
  185         auio.uio_resid = uap->nbyte;
  186         auio.uio_segflg = UIO_USERSPACE;
  187         error = kern_preadv(td, uap->fd, &auio, uap->offset);
  188         return(error);
  189 }
  190 
  191 int
  192 freebsd6_pread(td, uap)
  193         struct thread *td;
  194         struct freebsd6_pread_args *uap;
  195 {
  196         struct pread_args oargs;
  197 
  198         oargs.fd = uap->fd;
  199         oargs.buf = uap->buf;
  200         oargs.nbyte = uap->nbyte;
  201         oargs.offset = uap->offset;
  202         return (pread(td, &oargs));
  203 }
  204 
  205 /*
  206  * Scatter read system call.
  207  */
  208 #ifndef _SYS_SYSPROTO_H_
  209 struct readv_args {
  210         int     fd;
  211         struct  iovec *iovp;
  212         u_int   iovcnt;
  213 };
  214 #endif
  215 int
  216 readv(struct thread *td, struct readv_args *uap)
  217 {
  218         struct uio *auio;
  219         int error;
  220 
  221         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  222         if (error)
  223                 return (error);
  224         error = kern_readv(td, uap->fd, auio);
  225         free(auio, M_IOV);
  226         return (error);
  227 }
  228 
  229 int
  230 kern_readv(struct thread *td, int fd, struct uio *auio)
  231 {
  232         struct file *fp;
  233         int error;
  234 
  235         error = fget_read(td, fd, &fp);
  236         if (error)
  237                 return (error);
  238         error = dofileread(td, fd, fp, auio, (off_t)-1, 0);
  239         fdrop(fp, td);
  240         return (error);
  241 }
  242 
  243 /*
  244  * Scatter positioned read system call.
  245  */
  246 #ifndef _SYS_SYSPROTO_H_
  247 struct preadv_args {
  248         int     fd;
  249         struct  iovec *iovp;
  250         u_int   iovcnt;
  251         off_t   offset;
  252 };
  253 #endif
  254 int
  255 preadv(struct thread *td, struct preadv_args *uap)
  256 {
  257         struct uio *auio;
  258         int error;
  259 
  260         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  261         if (error)
  262                 return (error);
  263         error = kern_preadv(td, uap->fd, auio, uap->offset);
  264         free(auio, M_IOV);
  265         return (error);
  266 }
  267 
  268 int
  269 kern_preadv(td, fd, auio, offset)
  270         struct thread *td;
  271         int fd;
  272         struct uio *auio;
  273         off_t offset;
  274 {
  275         struct file *fp;
  276         int error;
  277 
  278         error = fget_read(td, fd, &fp);
  279         if (error)
  280                 return (error);
  281         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  282                 error = ESPIPE;
  283         else if (offset < 0 && fp->f_vnode->v_type != VCHR)
  284                 error = EINVAL;
  285         else
  286                 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET);
  287         fdrop(fp, td);
  288         return (error);
  289 }
  290 
  291 /*
  292  * Common code for readv and preadv that reads data in
  293  * from a file using the passed in uio, offset, and flags.
  294  */
  295 static int
  296 dofileread(td, fd, fp, auio, offset, flags)
  297         struct thread *td;
  298         int fd;
  299         struct file *fp;
  300         struct uio *auio;
  301         off_t offset;
  302         int flags;
  303 {
  304         ssize_t cnt;
  305         int error;
  306 #ifdef KTRACE
  307         struct uio *ktruio = NULL;
  308 #endif
  309 
  310         /* Finish zero length reads right here */
  311         if (auio->uio_resid == 0) {
  312                 td->td_retval[0] = 0;
  313                 return(0);
  314         }
  315         auio->uio_rw = UIO_READ;
  316         auio->uio_offset = offset;
  317         auio->uio_td = td;
  318 #ifdef KTRACE
  319         if (KTRPOINT(td, KTR_GENIO)) 
  320                 ktruio = cloneuio(auio);
  321 #endif
  322         cnt = auio->uio_resid;
  323         if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) {
  324                 if (auio->uio_resid != cnt && (error == ERESTART ||
  325                     error == EINTR || error == EWOULDBLOCK))
  326                         error = 0;
  327         }
  328         cnt -= auio->uio_resid;
  329 #ifdef KTRACE
  330         if (ktruio != NULL) {
  331                 ktruio->uio_resid = cnt;
  332                 ktrgenio(fd, UIO_READ, ktruio, error);
  333         }
  334 #endif
  335         td->td_retval[0] = cnt;
  336         return (error);
  337 }
  338 
  339 #ifndef _SYS_SYSPROTO_H_
  340 struct write_args {
  341         int     fd;
  342         const void *buf;
  343         size_t  nbyte;
  344 };
  345 #endif
  346 int
  347 write(td, uap)
  348         struct thread *td;
  349         struct write_args *uap;
  350 {
  351         struct uio auio;
  352         struct iovec aiov;
  353         int error;
  354 
  355         if (uap->nbyte > INT_MAX)
  356                 return (EINVAL);
  357         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  358         aiov.iov_len = uap->nbyte;
  359         auio.uio_iov = &aiov;
  360         auio.uio_iovcnt = 1;
  361         auio.uio_resid = uap->nbyte;
  362         auio.uio_segflg = UIO_USERSPACE;
  363         error = kern_writev(td, uap->fd, &auio);
  364         return(error);
  365 }
  366 
  367 /*
  368  * Positioned write system call.
  369  */
  370 #ifndef _SYS_SYSPROTO_H_
  371 struct pwrite_args {
  372         int     fd;
  373         const void *buf;
  374         size_t  nbyte;
  375         int     pad;
  376         off_t   offset;
  377 };
  378 #endif
  379 int
  380 pwrite(td, uap)
  381         struct thread *td;
  382         struct pwrite_args *uap;
  383 {
  384         struct uio auio;
  385         struct iovec aiov;
  386         int error;
  387 
  388         if (uap->nbyte > INT_MAX)
  389                 return (EINVAL);
  390         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  391         aiov.iov_len = uap->nbyte;
  392         auio.uio_iov = &aiov;
  393         auio.uio_iovcnt = 1;
  394         auio.uio_resid = uap->nbyte;
  395         auio.uio_segflg = UIO_USERSPACE;
  396         error = kern_pwritev(td, uap->fd, &auio, uap->offset);
  397         return(error);
  398 }
  399 
  400 int
  401 freebsd6_pwrite(td, uap)
  402         struct thread *td;
  403         struct freebsd6_pwrite_args *uap;
  404 {
  405         struct pwrite_args oargs;
  406 
  407         oargs.fd = uap->fd;
  408         oargs.buf = uap->buf;
  409         oargs.nbyte = uap->nbyte;
  410         oargs.offset = uap->offset;
  411         return (pwrite(td, &oargs));
  412 }
  413 
  414 /*
  415  * Gather write system call.
  416  */
  417 #ifndef _SYS_SYSPROTO_H_
  418 struct writev_args {
  419         int     fd;
  420         struct  iovec *iovp;
  421         u_int   iovcnt;
  422 };
  423 #endif
  424 int
  425 writev(struct thread *td, struct writev_args *uap)
  426 {
  427         struct uio *auio;
  428         int error;
  429 
  430         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  431         if (error)
  432                 return (error);
  433         error = kern_writev(td, uap->fd, auio);
  434         free(auio, M_IOV);
  435         return (error);
  436 }
  437 
  438 int
  439 kern_writev(struct thread *td, int fd, struct uio *auio)
  440 {
  441         struct file *fp;
  442         int error;
  443 
  444         error = fget_write(td, fd, &fp);
  445         if (error)
  446                 return (error);
  447         error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0);
  448         fdrop(fp, td);
  449         return (error);
  450 }
  451 
  452 /*
  453  * Gather positioned write system call.
  454  */
  455 #ifndef _SYS_SYSPROTO_H_
  456 struct pwritev_args {
  457         int     fd;
  458         struct  iovec *iovp;
  459         u_int   iovcnt;
  460         off_t   offset;
  461 };
  462 #endif
  463 int
  464 pwritev(struct thread *td, struct pwritev_args *uap)
  465 {
  466         struct uio *auio;
  467         int error;
  468 
  469         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  470         if (error)
  471                 return (error);
  472         error = kern_pwritev(td, uap->fd, auio, uap->offset);
  473         free(auio, M_IOV);
  474         return (error);
  475 }
  476 
  477 int
  478 kern_pwritev(td, fd, auio, offset)
  479         struct thread *td;
  480         struct uio *auio;
  481         int fd;
  482         off_t offset;
  483 {
  484         struct file *fp;
  485         int error;
  486 
  487         error = fget_write(td, fd, &fp);
  488         if (error)
  489                 return (error);
  490         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  491                 error = ESPIPE;
  492         else if (offset < 0 && fp->f_vnode->v_type != VCHR)
  493                 error = EINVAL;
  494         else
  495                 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET);
  496         fdrop(fp, td);
  497         return (error);
  498 }
  499 
  500 /*
  501  * Common code for writev and pwritev that writes data to
  502  * a file using the passed in uio, offset, and flags.
  503  */
  504 static int
  505 dofilewrite(td, fd, fp, auio, offset, flags)
  506         struct thread *td;
  507         int fd;
  508         struct file *fp;
  509         struct uio *auio;
  510         off_t offset;
  511         int flags;
  512 {
  513         ssize_t cnt;
  514         int error;
  515 #ifdef KTRACE
  516         struct uio *ktruio = NULL;
  517 #endif
  518 
  519         auio->uio_rw = UIO_WRITE;
  520         auio->uio_td = td;
  521         auio->uio_offset = offset;
  522 #ifdef KTRACE
  523         if (KTRPOINT(td, KTR_GENIO))
  524                 ktruio = cloneuio(auio);
  525 #endif
  526         cnt = auio->uio_resid;
  527         if (fp->f_type == DTYPE_VNODE)
  528                 bwillwrite();
  529         if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) {
  530                 if (auio->uio_resid != cnt && (error == ERESTART ||
  531                     error == EINTR || error == EWOULDBLOCK))
  532                         error = 0;
  533                 /* Socket layer is responsible for issuing SIGPIPE. */
  534                 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) {
  535                         PROC_LOCK(td->td_proc);
  536                         tdksignal(td, SIGPIPE, NULL);
  537                         PROC_UNLOCK(td->td_proc);
  538                 }
  539         }
  540         cnt -= auio->uio_resid;
  541 #ifdef KTRACE
  542         if (ktruio != NULL) {
  543                 ktruio->uio_resid = cnt;
  544                 ktrgenio(fd, UIO_WRITE, ktruio, error);
  545         }
  546 #endif
  547         td->td_retval[0] = cnt;
  548         return (error);
  549 }
  550 
  551 /*
  552  * Truncate a file given a file descriptor.
  553  *
  554  * Can't use fget_write() here, since must return EINVAL and not EBADF if the
  555  * descriptor isn't writable.
  556  */
  557 int
  558 kern_ftruncate(td, fd, length)
  559         struct thread *td;
  560         int fd;
  561         off_t length;
  562 {
  563         struct file *fp;
  564         int error;
  565 
  566         AUDIT_ARG_FD(fd);
  567         if (length < 0)
  568                 return (EINVAL);
  569         error = fget(td, fd, &fp);
  570         if (error)
  571                 return (error);
  572         AUDIT_ARG_FILE(td->td_proc, fp);
  573         if (!(fp->f_flag & FWRITE)) {
  574                 fdrop(fp, td);
  575                 return (EINVAL);
  576         }
  577         error = fo_truncate(fp, length, td->td_ucred, td);
  578         fdrop(fp, td);
  579         return (error);
  580 }
  581 
  582 #ifndef _SYS_SYSPROTO_H_
  583 struct ftruncate_args {
  584         int     fd;
  585         int     pad;
  586         off_t   length;
  587 };
  588 #endif
  589 int
  590 ftruncate(td, uap)
  591         struct thread *td;
  592         struct ftruncate_args *uap;
  593 {
  594 
  595         return (kern_ftruncate(td, uap->fd, uap->length));
  596 }
  597 
  598 #if defined(COMPAT_43)
  599 #ifndef _SYS_SYSPROTO_H_
  600 struct oftruncate_args {
  601         int     fd;
  602         long    length;
  603 };
  604 #endif
  605 int
  606 oftruncate(td, uap)
  607         struct thread *td;
  608         struct oftruncate_args *uap;
  609 {
  610 
  611         return (kern_ftruncate(td, uap->fd, uap->length));
  612 }
  613 #endif /* COMPAT_43 */
  614 
  615 #ifndef _SYS_SYSPROTO_H_
  616 struct ioctl_args {
  617         int     fd;
  618         u_long  com;
  619         caddr_t data;
  620 };
  621 #endif
  622 /* ARGSUSED */
  623 int
  624 ioctl(struct thread *td, struct ioctl_args *uap)
  625 {
  626         u_long com;
  627         int arg, error;
  628         u_int size;
  629         caddr_t data;
  630 
  631         if (uap->com > 0xffffffff) {
  632                 printf(
  633                     "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
  634                     td->td_proc->p_pid, td->td_name, uap->com);
  635                 uap->com &= 0xffffffff;
  636         }
  637         com = uap->com;
  638 
  639         /*
  640          * Interpret high order word to find amount of data to be
  641          * copied to/from the user's address space.
  642          */
  643         size = IOCPARM_LEN(com);
  644         if ((size > IOCPARM_MAX) ||
  645             ((com & (IOC_VOID  | IOC_IN | IOC_OUT)) == 0) ||
  646 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
  647             ((com & IOC_OUT) && size == 0) ||
  648 #else
  649             ((com & (IOC_IN | IOC_OUT)) && size == 0) ||
  650 #endif
  651             ((com & IOC_VOID) && size > 0 && size != sizeof(int)))
  652                 return (ENOTTY);
  653 
  654         if (size > 0) {
  655                 if (com & IOC_VOID) {
  656                         /* Integer argument. */
  657                         arg = (intptr_t)uap->data;
  658                         data = (void *)&arg;
  659                         size = 0;
  660                 } else
  661                         data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
  662         } else
  663                 data = (void *)&uap->data;
  664         if (com & IOC_IN) {
  665                 error = copyin(uap->data, data, (u_int)size);
  666                 if (error) {
  667                         if (size > 0)
  668                                 free(data, M_IOCTLOPS);
  669                         return (error);
  670                 }
  671         } else if (com & IOC_OUT) {
  672                 /*
  673                  * Zero the buffer so the user always
  674                  * gets back something deterministic.
  675                  */
  676                 bzero(data, size);
  677         }
  678 
  679         error = kern_ioctl(td, uap->fd, com, data);
  680 
  681         if (error == 0 && (com & IOC_OUT))
  682                 error = copyout(data, uap->data, (u_int)size);
  683 
  684         if (size > 0)
  685                 free(data, M_IOCTLOPS);
  686         return (error);
  687 }
  688 
  689 int
  690 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
  691 {
  692         struct file *fp;
  693         struct filedesc *fdp;
  694         int error;
  695         int tmp;
  696 
  697         AUDIT_ARG_FD(fd);
  698         AUDIT_ARG_CMD(com);
  699         if ((error = fget(td, fd, &fp)) != 0)
  700                 return (error);
  701         if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
  702                 fdrop(fp, td);
  703                 return (EBADF);
  704         }
  705         fdp = td->td_proc->p_fd;
  706         switch (com) {
  707         case FIONCLEX:
  708                 FILEDESC_XLOCK(fdp);
  709                 fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE;
  710                 FILEDESC_XUNLOCK(fdp);
  711                 goto out;
  712         case FIOCLEX:
  713                 FILEDESC_XLOCK(fdp);
  714                 fdp->fd_ofileflags[fd] |= UF_EXCLOSE;
  715                 FILEDESC_XUNLOCK(fdp);
  716                 goto out;
  717         case FIONBIO:
  718                 if ((tmp = *(int *)data))
  719                         atomic_set_int(&fp->f_flag, FNONBLOCK);
  720                 else
  721                         atomic_clear_int(&fp->f_flag, FNONBLOCK);
  722                 data = (void *)&tmp;
  723                 break;
  724         case FIOASYNC:
  725                 if ((tmp = *(int *)data))
  726                         atomic_set_int(&fp->f_flag, FASYNC);
  727                 else
  728                         atomic_clear_int(&fp->f_flag, FASYNC);
  729                 data = (void *)&tmp;
  730                 break;
  731         }
  732 
  733         error = fo_ioctl(fp, com, data, td->td_ucred, td);
  734 out:
  735         fdrop(fp, td);
  736         return (error);
  737 }
  738 
  739 int
  740 poll_no_poll(int events)
  741 {
  742         /*
  743          * Return true for read/write.  If the user asked for something
  744          * special, return POLLNVAL, so that clients have a way of
  745          * determining reliably whether or not the extended
  746          * functionality is present without hard-coding knowledge
  747          * of specific filesystem implementations.
  748          */
  749         if (events & ~POLLSTANDARD)
  750                 return (POLLNVAL);
  751 
  752         return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
  753 }
  754 
  755 int
  756 pselect(struct thread *td, struct pselect_args *uap)
  757 {
  758         struct timespec ts;
  759         struct timeval tv, *tvp;
  760         sigset_t set, *uset;
  761         int error;
  762 
  763         if (uap->ts != NULL) {
  764                 error = copyin(uap->ts, &ts, sizeof(ts));
  765                 if (error != 0)
  766                     return (error);
  767                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
  768                 tvp = &tv;
  769         } else
  770                 tvp = NULL;
  771         if (uap->sm != NULL) {
  772                 error = copyin(uap->sm, &set, sizeof(set));
  773                 if (error != 0)
  774                         return (error);
  775                 uset = &set;
  776         } else
  777                 uset = NULL;
  778         return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  779             uset, NFDBITS));
  780 }
  781 
  782 int
  783 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
  784     struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
  785 {
  786         int error;
  787 
  788         if (uset != NULL) {
  789                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
  790                     &td->td_oldsigmask, 0);
  791                 if (error != 0)
  792                         return (error);
  793                 td->td_pflags |= TDP_OLDMASK;
  794                 /*
  795                  * Make sure that ast() is called on return to
  796                  * usermode and TDP_OLDMASK is cleared, restoring old
  797                  * sigmask.
  798                  */
  799                 thread_lock(td);
  800                 td->td_flags |= TDF_ASTPENDING;
  801                 thread_unlock(td);
  802         }
  803         error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
  804         return (error);
  805 }
  806 
  807 #ifndef _SYS_SYSPROTO_H_
  808 struct select_args {
  809         int     nd;
  810         fd_set  *in, *ou, *ex;
  811         struct  timeval *tv;
  812 };
  813 #endif
  814 int
  815 select(struct thread *td, struct select_args *uap)
  816 {
  817         struct timeval tv, *tvp;
  818         int error;
  819 
  820         if (uap->tv != NULL) {
  821                 error = copyin(uap->tv, &tv, sizeof(tv));
  822                 if (error)
  823                         return (error);
  824                 tvp = &tv;
  825         } else
  826                 tvp = NULL;
  827 
  828         return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  829             NFDBITS));
  830 }
  831 
  832 /*
  833  * In the unlikely case when user specified n greater then the last
  834  * open file descriptor, check that no bits are set after the last
  835  * valid fd.  We must return EBADF if any is set.
  836  *
  837  * There are applications that rely on the behaviour.
  838  *
  839  * nd is fd_lastfile + 1.
  840  */
  841 static int
  842 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits)
  843 {
  844         char *addr, *oaddr;
  845         int b, i, res;
  846         uint8_t bits;
  847 
  848         if (nd >= ndu || fd_in == NULL)
  849                 return (0);
  850 
  851         oaddr = NULL;
  852         bits = 0; /* silence gcc */
  853         for (i = nd; i < ndu; i++) {
  854                 b = i / NBBY;
  855 #if BYTE_ORDER == LITTLE_ENDIAN
  856                 addr = (char *)fd_in + b;
  857 #else
  858                 addr = (char *)fd_in;
  859                 if (abi_nfdbits == NFDBITS) {
  860                         addr += rounddown(b, sizeof(fd_mask)) +
  861                             sizeof(fd_mask) - 1 - b % sizeof(fd_mask);
  862                 } else {
  863                         addr += rounddown(b, sizeof(uint32_t)) +
  864                             sizeof(uint32_t) - 1 - b % sizeof(uint32_t);
  865                 }
  866 #endif
  867                 if (addr != oaddr) {
  868                         res = fubyte(addr);
  869                         if (res == -1)
  870                                 return (EFAULT);
  871                         oaddr = addr;
  872                         bits = res;
  873                 }
  874                 if ((bits & (1 << (i % NBBY))) != 0)
  875                         return (EBADF);
  876         }
  877         return (0);
  878 }
  879 
  880 int
  881 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
  882     fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
  883 {
  884         struct filedesc *fdp;
  885         /*
  886          * The magic 2048 here is chosen to be just enough for FD_SETSIZE
  887          * infds with the new FD_SETSIZE of 1024, and more than enough for
  888          * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
  889          * of 256.
  890          */
  891         fd_mask s_selbits[howmany(2048, NFDBITS)];
  892         fd_mask *ibits[3], *obits[3], *selbits, *sbp;
  893         struct timeval atv, rtv, ttv;
  894         int error, lf, ndu, timo;
  895         u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
  896 
  897         if (nd < 0)
  898                 return (EINVAL);
  899         fdp = td->td_proc->p_fd;
  900         ndu = nd;
  901         lf = fdp->fd_lastfile;
  902         if (nd > lf + 1)
  903                 nd = lf + 1;
  904 
  905         error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits);
  906         if (error != 0)
  907                 return (error);
  908         error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits);
  909         if (error != 0)
  910                 return (error);
  911         error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits);
  912         if (error != 0)
  913                 return (error);
  914 
  915         /*
  916          * Allocate just enough bits for the non-null fd_sets.  Use the
  917          * preallocated auto buffer if possible.
  918          */
  919         nfdbits = roundup(nd, NFDBITS);
  920         ncpbytes = nfdbits / NBBY;
  921         ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
  922         nbufbytes = 0;
  923         if (fd_in != NULL)
  924                 nbufbytes += 2 * ncpbytes;
  925         if (fd_ou != NULL)
  926                 nbufbytes += 2 * ncpbytes;
  927         if (fd_ex != NULL)
  928                 nbufbytes += 2 * ncpbytes;
  929         if (nbufbytes <= sizeof s_selbits)
  930                 selbits = &s_selbits[0];
  931         else
  932                 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
  933 
  934         /*
  935          * Assign pointers into the bit buffers and fetch the input bits.
  936          * Put the output buffers together so that they can be bzeroed
  937          * together.
  938          */
  939         sbp = selbits;
  940 #define getbits(name, x) \
  941         do {                                                            \
  942                 if (name == NULL) {                                     \
  943                         ibits[x] = NULL;                                \
  944                         obits[x] = NULL;                                \
  945                 } else {                                                \
  946                         ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp;   \
  947                         obits[x] = sbp;                                 \
  948                         sbp += ncpbytes / sizeof *sbp;                  \
  949                         error = copyin(name, ibits[x], ncpubytes);      \
  950                         if (error != 0)                                 \
  951                                 goto done;                              \
  952                         bzero((char *)ibits[x] + ncpubytes,             \
  953                             ncpbytes - ncpubytes);                      \
  954                 }                                                       \
  955         } while (0)
  956         getbits(fd_in, 0);
  957         getbits(fd_ou, 1);
  958         getbits(fd_ex, 2);
  959 #undef  getbits
  960 
  961 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
  962         /*
  963          * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
  964          * we are running under 32-bit emulation. This should be more
  965          * generic.
  966          */
  967 #define swizzle_fdset(bits)                                             \
  968         if (abi_nfdbits != NFDBITS && bits != NULL) {                   \
  969                 int i;                                                  \
  970                 for (i = 0; i < ncpbytes / sizeof *sbp; i++)            \
  971                         bits[i] = (bits[i] >> 32) | (bits[i] << 32);    \
  972         }
  973 #else
  974 #define swizzle_fdset(bits)
  975 #endif
  976 
  977         /* Make sure the bit order makes it through an ABI transition */
  978         swizzle_fdset(ibits[0]);
  979         swizzle_fdset(ibits[1]);
  980         swizzle_fdset(ibits[2]);
  981         
  982         if (nbufbytes != 0)
  983                 bzero(selbits, nbufbytes / 2);
  984 
  985         if (tvp != NULL) {
  986                 atv = *tvp;
  987                 if (itimerfix(&atv)) {
  988                         error = EINVAL;
  989                         goto done;
  990                 }
  991                 getmicrouptime(&rtv);
  992                 timevaladd(&atv, &rtv);
  993         } else {
  994                 atv.tv_sec = 0;
  995                 atv.tv_usec = 0;
  996         }
  997         timo = 0;
  998         seltdinit(td);
  999         /* Iterate until the timeout expires or descriptors become ready. */
 1000         for (;;) {
 1001                 error = selscan(td, ibits, obits, nd);
 1002                 if (error || td->td_retval[0] != 0)
 1003                         break;
 1004                 if (atv.tv_sec || atv.tv_usec) {
 1005                         getmicrouptime(&rtv);
 1006                         if (timevalcmp(&rtv, &atv, >=))
 1007                                 break;
 1008                         ttv = atv;
 1009                         timevalsub(&ttv, &rtv);
 1010                         timo = ttv.tv_sec > 24 * 60 * 60 ?
 1011                             24 * 60 * 60 * hz : tvtohz(&ttv);
 1012                 }
 1013                 error = seltdwait(td, timo);
 1014                 if (error)
 1015                         break;
 1016                 error = selrescan(td, ibits, obits);
 1017                 if (error || td->td_retval[0] != 0)
 1018                         break;
 1019         }
 1020         seltdclear(td);
 1021 
 1022 done:
 1023         /* select is not restarted after signals... */
 1024         if (error == ERESTART)
 1025                 error = EINTR;
 1026         if (error == EWOULDBLOCK)
 1027                 error = 0;
 1028 
 1029         /* swizzle bit order back, if necessary */
 1030         swizzle_fdset(obits[0]);
 1031         swizzle_fdset(obits[1]);
 1032         swizzle_fdset(obits[2]);
 1033 #undef swizzle_fdset
 1034 
 1035 #define putbits(name, x) \
 1036         if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
 1037                 error = error2;
 1038         if (error == 0) {
 1039                 int error2;
 1040 
 1041                 putbits(fd_in, 0);
 1042                 putbits(fd_ou, 1);
 1043                 putbits(fd_ex, 2);
 1044 #undef putbits
 1045         }
 1046         if (selbits != &s_selbits[0])
 1047                 free(selbits, M_SELECT);
 1048 
 1049         return (error);
 1050 }
 1051 /* 
 1052  * Convert a select bit set to poll flags.
 1053  *
 1054  * The backend always returns POLLHUP/POLLERR if appropriate and we
 1055  * return this as a set bit in any set.
 1056  */
 1057 static int select_flags[3] = {
 1058     POLLRDNORM | POLLHUP | POLLERR,
 1059     POLLWRNORM | POLLHUP | POLLERR,
 1060     POLLRDBAND | POLLERR
 1061 };
 1062 
 1063 /*
 1064  * Compute the fo_poll flags required for a fd given by the index and
 1065  * bit position in the fd_mask array.
 1066  */
 1067 static __inline int
 1068 selflags(fd_mask **ibits, int idx, fd_mask bit)
 1069 {
 1070         int flags;
 1071         int msk;
 1072 
 1073         flags = 0;
 1074         for (msk = 0; msk < 3; msk++) {
 1075                 if (ibits[msk] == NULL)
 1076                         continue;
 1077                 if ((ibits[msk][idx] & bit) == 0)
 1078                         continue;
 1079                 flags |= select_flags[msk];
 1080         }
 1081         return (flags);
 1082 }
 1083 
 1084 /*
 1085  * Set the appropriate output bits given a mask of fired events and the
 1086  * input bits originally requested.
 1087  */
 1088 static __inline int
 1089 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
 1090 {
 1091         int msk;
 1092         int n;
 1093 
 1094         n = 0;
 1095         for (msk = 0; msk < 3; msk++) {
 1096                 if ((events & select_flags[msk]) == 0)
 1097                         continue;
 1098                 if (ibits[msk] == NULL)
 1099                         continue;
 1100                 if ((ibits[msk][idx] & bit) == 0)
 1101                         continue;
 1102                 /*
 1103                  * XXX Check for a duplicate set.  This can occur because a
 1104                  * socket calls selrecord() twice for each poll() call
 1105                  * resulting in two selfds per real fd.  selrescan() will
 1106                  * call selsetbits twice as a result.
 1107                  */
 1108                 if ((obits[msk][idx] & bit) != 0)
 1109                         continue;
 1110                 obits[msk][idx] |= bit;
 1111                 n++;
 1112         }
 1113 
 1114         return (n);
 1115 }
 1116 
 1117 /*
 1118  * Traverse the list of fds attached to this thread's seltd and check for
 1119  * completion.
 1120  */
 1121 static int
 1122 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
 1123 {
 1124         struct filedesc *fdp;
 1125         struct selinfo *si;
 1126         struct seltd *stp;
 1127         struct selfd *sfp;
 1128         struct selfd *sfn;
 1129         struct file *fp;
 1130         fd_mask bit;
 1131         int fd, ev, n, idx;
 1132 
 1133         fdp = td->td_proc->p_fd;
 1134         stp = td->td_sel;
 1135         n = 0;
 1136         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1137                 fd = (int)(uintptr_t)sfp->sf_cookie;
 1138                 si = sfp->sf_si;
 1139                 selfdfree(stp, sfp);
 1140                 /* If the selinfo wasn't cleared the event didn't fire. */
 1141                 if (si != NULL)
 1142                         continue;
 1143                 if ((fp = fget_unlocked(fdp, fd)) == NULL)
 1144                         return (EBADF);
 1145                 idx = fd / NFDBITS;
 1146                 bit = (fd_mask)1 << (fd % NFDBITS);
 1147                 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
 1148                 fdrop(fp, td);
 1149                 if (ev != 0)
 1150                         n += selsetbits(ibits, obits, idx, bit, ev);
 1151         }
 1152         stp->st_flags = 0;
 1153         td->td_retval[0] = n;
 1154         return (0);
 1155 }
 1156 
 1157 /*
 1158  * Perform the initial filedescriptor scan and register ourselves with
 1159  * each selinfo.
 1160  */
 1161 static int
 1162 selscan(td, ibits, obits, nfd)
 1163         struct thread *td;
 1164         fd_mask **ibits, **obits;
 1165         int nfd;
 1166 {
 1167         struct filedesc *fdp;
 1168         struct file *fp;
 1169         fd_mask bit;
 1170         int ev, flags, end, fd;
 1171         int n, idx;
 1172 
 1173         fdp = td->td_proc->p_fd;
 1174         n = 0;
 1175         for (idx = 0, fd = 0; fd < nfd; idx++) {
 1176                 end = imin(fd + NFDBITS, nfd);
 1177                 for (bit = 1; fd < end; bit <<= 1, fd++) {
 1178                         /* Compute the list of events we're interested in. */
 1179                         flags = selflags(ibits, idx, bit);
 1180                         if (flags == 0)
 1181                                 continue;
 1182                         if ((fp = fget_unlocked(fdp, fd)) == NULL)
 1183                                 return (EBADF);
 1184                         selfdalloc(td, (void *)(uintptr_t)fd);
 1185                         ev = fo_poll(fp, flags, td->td_ucred, td);
 1186                         fdrop(fp, td);
 1187                         if (ev != 0)
 1188                                 n += selsetbits(ibits, obits, idx, bit, ev);
 1189                 }
 1190         }
 1191 
 1192         td->td_retval[0] = n;
 1193         return (0);
 1194 }
 1195 
 1196 #ifndef _SYS_SYSPROTO_H_
 1197 struct poll_args {
 1198         struct pollfd *fds;
 1199         u_int   nfds;
 1200         int     timeout;
 1201 };
 1202 #endif
 1203 int
 1204 poll(td, uap)
 1205         struct thread *td;
 1206         struct poll_args *uap;
 1207 {
 1208         struct pollfd *bits;
 1209         struct pollfd smallbits[32];
 1210         struct timeval atv, rtv, ttv;
 1211         int error, timo;
 1212         u_int nfds;
 1213         size_t ni;
 1214 
 1215         nfds = uap->nfds;
 1216         if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 
 1217                 return (EINVAL);
 1218         ni = nfds * sizeof(struct pollfd);
 1219         if (ni > sizeof(smallbits))
 1220                 bits = malloc(ni, M_TEMP, M_WAITOK);
 1221         else
 1222                 bits = smallbits;
 1223         error = copyin(uap->fds, bits, ni);
 1224         if (error)
 1225                 goto done;
 1226         if (uap->timeout != INFTIM) {
 1227                 atv.tv_sec = uap->timeout / 1000;
 1228                 atv.tv_usec = (uap->timeout % 1000) * 1000;
 1229                 if (itimerfix(&atv)) {
 1230                         error = EINVAL;
 1231                         goto done;
 1232                 }
 1233                 getmicrouptime(&rtv);
 1234                 timevaladd(&atv, &rtv);
 1235         } else {
 1236                 atv.tv_sec = 0;
 1237                 atv.tv_usec = 0;
 1238         }
 1239         timo = 0;
 1240         seltdinit(td);
 1241         /* Iterate until the timeout expires or descriptors become ready. */
 1242         for (;;) {
 1243                 error = pollscan(td, bits, nfds);
 1244                 if (error || td->td_retval[0] != 0)
 1245                         break;
 1246                 if (atv.tv_sec || atv.tv_usec) {
 1247                         getmicrouptime(&rtv);
 1248                         if (timevalcmp(&rtv, &atv, >=))
 1249                                 break;
 1250                         ttv = atv;
 1251                         timevalsub(&ttv, &rtv);
 1252                         timo = ttv.tv_sec > 24 * 60 * 60 ?
 1253                             24 * 60 * 60 * hz : tvtohz(&ttv);
 1254                 }
 1255                 error = seltdwait(td, timo);
 1256                 if (error)
 1257                         break;
 1258                 error = pollrescan(td);
 1259                 if (error || td->td_retval[0] != 0)
 1260                         break;
 1261         }
 1262         seltdclear(td);
 1263 
 1264 done:
 1265         /* poll is not restarted after signals... */
 1266         if (error == ERESTART)
 1267                 error = EINTR;
 1268         if (error == EWOULDBLOCK)
 1269                 error = 0;
 1270         if (error == 0) {
 1271                 error = pollout(td, bits, uap->fds, nfds);
 1272                 if (error)
 1273                         goto out;
 1274         }
 1275 out:
 1276         if (ni > sizeof(smallbits))
 1277                 free(bits, M_TEMP);
 1278         return (error);
 1279 }
 1280 
 1281 static int
 1282 pollrescan(struct thread *td)
 1283 {
 1284         struct seltd *stp;
 1285         struct selfd *sfp;
 1286         struct selfd *sfn;
 1287         struct selinfo *si;
 1288         struct filedesc *fdp;
 1289         struct file *fp;
 1290         struct pollfd *fd;
 1291         int n;
 1292 
 1293         n = 0;
 1294         fdp = td->td_proc->p_fd;
 1295         stp = td->td_sel;
 1296         FILEDESC_SLOCK(fdp);
 1297         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1298                 fd = (struct pollfd *)sfp->sf_cookie;
 1299                 si = sfp->sf_si;
 1300                 selfdfree(stp, sfp);
 1301                 /* If the selinfo wasn't cleared the event didn't fire. */
 1302                 if (si != NULL)
 1303                         continue;
 1304                 fp = fdp->fd_ofiles[fd->fd];
 1305                 if (fp == NULL) {
 1306                         fd->revents = POLLNVAL;
 1307                         n++;
 1308                         continue;
 1309                 }
 1310                 /*
 1311                  * Note: backend also returns POLLHUP and
 1312                  * POLLERR if appropriate.
 1313                  */
 1314                 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
 1315                 if (fd->revents != 0)
 1316                         n++;
 1317         }
 1318         FILEDESC_SUNLOCK(fdp);
 1319         stp->st_flags = 0;
 1320         td->td_retval[0] = n;
 1321         return (0);
 1322 }
 1323 
 1324 
 1325 static int
 1326 pollout(td, fds, ufds, nfd)
 1327         struct thread *td;
 1328         struct pollfd *fds;
 1329         struct pollfd *ufds;
 1330         u_int nfd;
 1331 {
 1332         int error = 0;
 1333         u_int i = 0;
 1334         u_int n = 0;
 1335 
 1336         for (i = 0; i < nfd; i++) {
 1337                 error = copyout(&fds->revents, &ufds->revents,
 1338                     sizeof(ufds->revents));
 1339                 if (error)
 1340                         return (error);
 1341                 if (fds->revents != 0)
 1342                         n++;
 1343                 fds++;
 1344                 ufds++;
 1345         }
 1346         td->td_retval[0] = n;
 1347         return (0);
 1348 }
 1349 
 1350 static int
 1351 pollscan(td, fds, nfd)
 1352         struct thread *td;
 1353         struct pollfd *fds;
 1354         u_int nfd;
 1355 {
 1356         struct filedesc *fdp = td->td_proc->p_fd;
 1357         int i;
 1358         struct file *fp;
 1359         int n = 0;
 1360 
 1361         FILEDESC_SLOCK(fdp);
 1362         for (i = 0; i < nfd; i++, fds++) {
 1363                 if (fds->fd >= fdp->fd_nfiles) {
 1364                         fds->revents = POLLNVAL;
 1365                         n++;
 1366                 } else if (fds->fd < 0) {
 1367                         fds->revents = 0;
 1368                 } else {
 1369                         fp = fdp->fd_ofiles[fds->fd];
 1370                         if (fp == NULL) {
 1371                                 fds->revents = POLLNVAL;
 1372                                 n++;
 1373                         } else {
 1374                                 /*
 1375                                  * Note: backend also returns POLLHUP and
 1376                                  * POLLERR if appropriate.
 1377                                  */
 1378                                 selfdalloc(td, fds);
 1379                                 fds->revents = fo_poll(fp, fds->events,
 1380                                     td->td_ucred, td);
 1381                                 /*
 1382                                  * POSIX requires POLLOUT to be never
 1383                                  * set simultaneously with POLLHUP.
 1384                                  */
 1385                                 if ((fds->revents & POLLHUP) != 0)
 1386                                         fds->revents &= ~POLLOUT;
 1387 
 1388                                 if (fds->revents != 0)
 1389                                         n++;
 1390                         }
 1391                 }
 1392         }
 1393         FILEDESC_SUNLOCK(fdp);
 1394         td->td_retval[0] = n;
 1395         return (0);
 1396 }
 1397 
 1398 /*
 1399  * OpenBSD poll system call.
 1400  *
 1401  * XXX this isn't quite a true representation..  OpenBSD uses select ops.
 1402  */
 1403 #ifndef _SYS_SYSPROTO_H_
 1404 struct openbsd_poll_args {
 1405         struct pollfd *fds;
 1406         u_int   nfds;
 1407         int     timeout;
 1408 };
 1409 #endif
 1410 int
 1411 openbsd_poll(td, uap)
 1412         register struct thread *td;
 1413         register struct openbsd_poll_args *uap;
 1414 {
 1415         return (poll(td, (struct poll_args *)uap));
 1416 }
 1417 
 1418 /*
 1419  * XXX This was created specifically to support netncp and netsmb.  This
 1420  * allows the caller to specify a socket to wait for events on.  It returns
 1421  * 0 if any events matched and an error otherwise.  There is no way to
 1422  * determine which events fired.
 1423  */
 1424 int
 1425 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
 1426 {
 1427         struct timeval atv, rtv, ttv;
 1428         int error, timo;
 1429 
 1430         if (tvp != NULL) {
 1431                 atv = *tvp;
 1432                 if (itimerfix(&atv))
 1433                         return (EINVAL);
 1434                 getmicrouptime(&rtv);
 1435                 timevaladd(&atv, &rtv);
 1436         } else {
 1437                 atv.tv_sec = 0;
 1438                 atv.tv_usec = 0;
 1439         }
 1440 
 1441         timo = 0;
 1442         seltdinit(td);
 1443         /*
 1444          * Iterate until the timeout expires or the socket becomes ready.
 1445          */
 1446         for (;;) {
 1447                 selfdalloc(td, NULL);
 1448                 error = sopoll(so, events, NULL, td);
 1449                 /* error here is actually the ready events. */
 1450                 if (error)
 1451                         return (0);
 1452                 if (atv.tv_sec || atv.tv_usec) {
 1453                         getmicrouptime(&rtv);
 1454                         if (timevalcmp(&rtv, &atv, >=)) {
 1455                                 seltdclear(td);
 1456                                 return (EWOULDBLOCK);
 1457                         }
 1458                         ttv = atv;
 1459                         timevalsub(&ttv, &rtv);
 1460                         timo = ttv.tv_sec > 24 * 60 * 60 ?
 1461                             24 * 60 * 60 * hz : tvtohz(&ttv);
 1462                 }
 1463                 error = seltdwait(td, timo);
 1464                 seltdclear(td);
 1465                 if (error)
 1466                         break;
 1467         }
 1468         /* XXX Duplicates ncp/smb behavior. */
 1469         if (error == ERESTART)
 1470                 error = 0;
 1471         return (error);
 1472 }
 1473 
 1474 /*
 1475  * Preallocate two selfds associated with 'cookie'.  Some fo_poll routines
 1476  * have two select sets, one for read and another for write.
 1477  */
 1478 static void
 1479 selfdalloc(struct thread *td, void *cookie)
 1480 {
 1481         struct seltd *stp;
 1482 
 1483         stp = td->td_sel;
 1484         if (stp->st_free1 == NULL)
 1485                 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1486         stp->st_free1->sf_td = stp;
 1487         stp->st_free1->sf_cookie = cookie;
 1488         if (stp->st_free2 == NULL)
 1489                 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1490         stp->st_free2->sf_td = stp;
 1491         stp->st_free2->sf_cookie = cookie;
 1492 }
 1493 
 1494 static void
 1495 selfdfree(struct seltd *stp, struct selfd *sfp)
 1496 {
 1497         STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
 1498         mtx_lock(sfp->sf_mtx);
 1499         if (sfp->sf_si)
 1500                 TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
 1501         mtx_unlock(sfp->sf_mtx);
 1502         uma_zfree(selfd_zone, sfp);
 1503 }
 1504 
 1505 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */
 1506 void
 1507 seldrain(sip)
 1508         struct selinfo *sip;
 1509 {
 1510 
 1511         /*
 1512          * This feature is already provided by doselwakeup(), thus it is
 1513          * enough to go for it.
 1514          * Eventually, the context, should take care to avoid races
 1515          * between thread calling select()/poll() and file descriptor
 1516          * detaching, but, again, the races are just the same as
 1517          * selwakeup().
 1518          */
 1519         doselwakeup(sip, -1);
 1520 }
 1521 
 1522 /*
 1523  * Record a select request.
 1524  */
 1525 void
 1526 selrecord(selector, sip)
 1527         struct thread *selector;
 1528         struct selinfo *sip;
 1529 {
 1530         struct selfd *sfp;
 1531         struct seltd *stp;
 1532         struct mtx *mtxp;
 1533 
 1534         stp = selector->td_sel;
 1535         /*
 1536          * Don't record when doing a rescan.
 1537          */
 1538         if (stp->st_flags & SELTD_RESCAN)
 1539                 return;
 1540         /*
 1541          * Grab one of the preallocated descriptors.
 1542          */
 1543         sfp = NULL;
 1544         if ((sfp = stp->st_free1) != NULL)
 1545                 stp->st_free1 = NULL;
 1546         else if ((sfp = stp->st_free2) != NULL)
 1547                 stp->st_free2 = NULL;
 1548         else
 1549                 panic("selrecord: No free selfd on selq");
 1550         mtxp = sip->si_mtx;
 1551         if (mtxp == NULL)
 1552                 mtxp = mtx_pool_find(mtxpool_select, sip);
 1553         /*
 1554          * Initialize the sfp and queue it in the thread.
 1555          */
 1556         sfp->sf_si = sip;
 1557         sfp->sf_mtx = mtxp;
 1558         STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
 1559         /*
 1560          * Now that we've locked the sip, check for initialization.
 1561          */
 1562         mtx_lock(mtxp);
 1563         if (sip->si_mtx == NULL) {
 1564                 sip->si_mtx = mtxp;
 1565                 TAILQ_INIT(&sip->si_tdlist);
 1566         }
 1567         /*
 1568          * Add this thread to the list of selfds listening on this selinfo.
 1569          */
 1570         TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
 1571         mtx_unlock(sip->si_mtx);
 1572 }
 1573 
 1574 /* Wake up a selecting thread. */
 1575 void
 1576 selwakeup(sip)
 1577         struct selinfo *sip;
 1578 {
 1579         doselwakeup(sip, -1);
 1580 }
 1581 
 1582 /* Wake up a selecting thread, and set its priority. */
 1583 void
 1584 selwakeuppri(sip, pri)
 1585         struct selinfo *sip;
 1586         int pri;
 1587 {
 1588         doselwakeup(sip, pri);
 1589 }
 1590 
 1591 /*
 1592  * Do a wakeup when a selectable event occurs.
 1593  */
 1594 static void
 1595 doselwakeup(sip, pri)
 1596         struct selinfo *sip;
 1597         int pri;
 1598 {
 1599         struct selfd *sfp;
 1600         struct selfd *sfn;
 1601         struct seltd *stp;
 1602 
 1603         /* If it's not initialized there can't be any waiters. */
 1604         if (sip->si_mtx == NULL)
 1605                 return;
 1606         /*
 1607          * Locking the selinfo locks all selfds associated with it.
 1608          */
 1609         mtx_lock(sip->si_mtx);
 1610         TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
 1611                 /*
 1612                  * Once we remove this sfp from the list and clear the
 1613                  * sf_si seltdclear will know to ignore this si.
 1614                  */
 1615                 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
 1616                 sfp->sf_si = NULL;
 1617                 stp = sfp->sf_td;
 1618                 mtx_lock(&stp->st_mtx);
 1619                 stp->st_flags |= SELTD_PENDING;
 1620                 cv_broadcastpri(&stp->st_wait, pri);
 1621                 mtx_unlock(&stp->st_mtx);
 1622         }
 1623         mtx_unlock(sip->si_mtx);
 1624 }
 1625 
 1626 static void
 1627 seltdinit(struct thread *td)
 1628 {
 1629         struct seltd *stp;
 1630 
 1631         if ((stp = td->td_sel) != NULL)
 1632                 goto out;
 1633         td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
 1634         mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
 1635         cv_init(&stp->st_wait, "select");
 1636 out:
 1637         stp->st_flags = 0;
 1638         STAILQ_INIT(&stp->st_selq);
 1639 }
 1640 
 1641 static int
 1642 seltdwait(struct thread *td, int timo)
 1643 {
 1644         struct seltd *stp;
 1645         int error;
 1646 
 1647         stp = td->td_sel;
 1648         /*
 1649          * An event of interest may occur while we do not hold the seltd
 1650          * locked so check the pending flag before we sleep.
 1651          */
 1652         mtx_lock(&stp->st_mtx);
 1653         /*
 1654          * Any further calls to selrecord will be a rescan.
 1655          */
 1656         stp->st_flags |= SELTD_RESCAN;
 1657         if (stp->st_flags & SELTD_PENDING) {
 1658                 mtx_unlock(&stp->st_mtx);
 1659                 return (0);
 1660         }
 1661         if (timo > 0)
 1662                 error = cv_timedwait_sig(&stp->st_wait, &stp->st_mtx, timo);
 1663         else
 1664                 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
 1665         mtx_unlock(&stp->st_mtx);
 1666 
 1667         return (error);
 1668 }
 1669 
 1670 void
 1671 seltdfini(struct thread *td)
 1672 {
 1673         struct seltd *stp;
 1674 
 1675         stp = td->td_sel;
 1676         if (stp == NULL)
 1677                 return;
 1678         if (stp->st_free1)
 1679                 uma_zfree(selfd_zone, stp->st_free1);
 1680         if (stp->st_free2)
 1681                 uma_zfree(selfd_zone, stp->st_free2);
 1682         td->td_sel = NULL;
 1683         free(stp, M_SELECT);
 1684 }
 1685 
 1686 /*
 1687  * Remove the references to the thread from all of the objects we were
 1688  * polling.
 1689  */
 1690 static void
 1691 seltdclear(struct thread *td)
 1692 {
 1693         struct seltd *stp;
 1694         struct selfd *sfp;
 1695         struct selfd *sfn;
 1696 
 1697         stp = td->td_sel;
 1698         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
 1699                 selfdfree(stp, sfp);
 1700         stp->st_flags = 0;
 1701 }
 1702 
 1703 static void selectinit(void *);
 1704 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
 1705 static void
 1706 selectinit(void *dummy __unused)
 1707 {
 1708 
 1709         selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
 1710             NULL, NULL, UMA_ALIGN_PTR, 0);
 1711         mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
 1712 }

Cache object: a7d4a67b6c3168b56da5d69ae786fcee


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