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: releng/8.1/sys/kern/sys_generic.c 208801 2010-06-04 14:06:59Z kib $");
   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 pollfd *, struct pollfd *, u_int);
   80 static int      pollscan(struct thread *, struct pollfd *, u_int);
   81 static int      pollrescan(struct thread *);
   82 static int      selscan(struct thread *, fd_mask **, fd_mask **, int);
   83 static int      selrescan(struct thread *, fd_mask **, fd_mask **);
   84 static void     selfdalloc(struct thread *, void *);
   85 static void     selfdfree(struct seltd *, struct selfd *);
   86 static int      dofileread(struct thread *, int, struct file *, struct uio *,
   87                     off_t, int);
   88 static int      dofilewrite(struct thread *, int, struct file *, struct uio *,
   89                     off_t, int);
   90 static void     doselwakeup(struct selinfo *, int);
   91 static void     seltdinit(struct thread *);
   92 static int      seltdwait(struct thread *, int);
   93 static void     seltdclear(struct thread *);
   94 
   95 /*
   96  * One seltd per-thread allocated on demand as needed.
   97  *
   98  *      t - protected by st_mtx
   99  *      k - Only accessed by curthread or read-only
  100  */
  101 struct seltd {
  102         STAILQ_HEAD(, selfd)    st_selq;        /* (k) List of selfds. */
  103         struct selfd            *st_free1;      /* (k) free fd for read set. */
  104         struct selfd            *st_free2;      /* (k) free fd for write set. */
  105         struct mtx              st_mtx;         /* Protects struct seltd */
  106         struct cv               st_wait;        /* (t) Wait channel. */
  107         int                     st_flags;       /* (t) SELTD_ flags. */
  108 };
  109 
  110 #define SELTD_PENDING   0x0001                  /* We have pending events. */
  111 #define SELTD_RESCAN    0x0002                  /* Doing a rescan. */
  112 
  113 /*
  114  * One selfd allocated per-thread per-file-descriptor.
  115  *      f - protected by sf_mtx
  116  */
  117 struct selfd {
  118         STAILQ_ENTRY(selfd)     sf_link;        /* (k) fds owned by this td. */
  119         TAILQ_ENTRY(selfd)      sf_threads;     /* (f) fds on this selinfo. */
  120         struct selinfo          *sf_si;         /* (f) selinfo when linked. */
  121         struct mtx              *sf_mtx;        /* Pointer to selinfo mtx. */
  122         struct seltd            *sf_td;         /* (k) owning seltd. */
  123         void                    *sf_cookie;     /* (k) fd or pollfd. */
  124 };
  125 
  126 static uma_zone_t selfd_zone;
  127 static struct mtx_pool *mtxpool_select;
  128 
  129 #ifndef _SYS_SYSPROTO_H_
  130 struct read_args {
  131         int     fd;
  132         void    *buf;
  133         size_t  nbyte;
  134 };
  135 #endif
  136 int
  137 read(td, uap)
  138         struct thread *td;
  139         struct read_args *uap;
  140 {
  141         struct uio auio;
  142         struct iovec aiov;
  143         int error;
  144 
  145         if (uap->nbyte > INT_MAX)
  146                 return (EINVAL);
  147         aiov.iov_base = uap->buf;
  148         aiov.iov_len = uap->nbyte;
  149         auio.uio_iov = &aiov;
  150         auio.uio_iovcnt = 1;
  151         auio.uio_resid = uap->nbyte;
  152         auio.uio_segflg = UIO_USERSPACE;
  153         error = kern_readv(td, uap->fd, &auio);
  154         return(error);
  155 }
  156 
  157 /*
  158  * Positioned read system call
  159  */
  160 #ifndef _SYS_SYSPROTO_H_
  161 struct pread_args {
  162         int     fd;
  163         void    *buf;
  164         size_t  nbyte;
  165         int     pad;
  166         off_t   offset;
  167 };
  168 #endif
  169 int
  170 pread(td, uap)
  171         struct thread *td;
  172         struct pread_args *uap;
  173 {
  174         struct uio auio;
  175         struct iovec aiov;
  176         int error;
  177 
  178         if (uap->nbyte > INT_MAX)
  179                 return (EINVAL);
  180         aiov.iov_base = uap->buf;
  181         aiov.iov_len = uap->nbyte;
  182         auio.uio_iov = &aiov;
  183         auio.uio_iovcnt = 1;
  184         auio.uio_resid = uap->nbyte;
  185         auio.uio_segflg = UIO_USERSPACE;
  186         error = kern_preadv(td, uap->fd, &auio, uap->offset);
  187         return(error);
  188 }
  189 
  190 int
  191 freebsd6_pread(td, uap)
  192         struct thread *td;
  193         struct freebsd6_pread_args *uap;
  194 {
  195         struct pread_args oargs;
  196 
  197         oargs.fd = uap->fd;
  198         oargs.buf = uap->buf;
  199         oargs.nbyte = uap->nbyte;
  200         oargs.offset = uap->offset;
  201         return (pread(td, &oargs));
  202 }
  203 
  204 /*
  205  * Scatter read system call.
  206  */
  207 #ifndef _SYS_SYSPROTO_H_
  208 struct readv_args {
  209         int     fd;
  210         struct  iovec *iovp;
  211         u_int   iovcnt;
  212 };
  213 #endif
  214 int
  215 readv(struct thread *td, struct readv_args *uap)
  216 {
  217         struct uio *auio;
  218         int error;
  219 
  220         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  221         if (error)
  222                 return (error);
  223         error = kern_readv(td, uap->fd, auio);
  224         free(auio, M_IOV);
  225         return (error);
  226 }
  227 
  228 int
  229 kern_readv(struct thread *td, int fd, struct uio *auio)
  230 {
  231         struct file *fp;
  232         int error;
  233 
  234         error = fget_read(td, fd, &fp);
  235         if (error)
  236                 return (error);
  237         error = dofileread(td, fd, fp, auio, (off_t)-1, 0);
  238         fdrop(fp, td);
  239         return (error);
  240 }
  241 
  242 /*
  243  * Scatter positioned read system call.
  244  */
  245 #ifndef _SYS_SYSPROTO_H_
  246 struct preadv_args {
  247         int     fd;
  248         struct  iovec *iovp;
  249         u_int   iovcnt;
  250         off_t   offset;
  251 };
  252 #endif
  253 int
  254 preadv(struct thread *td, struct preadv_args *uap)
  255 {
  256         struct uio *auio;
  257         int error;
  258 
  259         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  260         if (error)
  261                 return (error);
  262         error = kern_preadv(td, uap->fd, auio, uap->offset);
  263         free(auio, M_IOV);
  264         return (error);
  265 }
  266 
  267 int
  268 kern_preadv(td, fd, auio, offset)
  269         struct thread *td;
  270         int fd;
  271         struct uio *auio;
  272         off_t offset;
  273 {
  274         struct file *fp;
  275         int error;
  276 
  277         error = fget_read(td, fd, &fp);
  278         if (error)
  279                 return (error);
  280         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  281                 error = ESPIPE;
  282         else if (offset < 0 && fp->f_vnode->v_type != VCHR)
  283                 error = EINVAL;
  284         else
  285                 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET);
  286         fdrop(fp, td);
  287         return (error);
  288 }
  289 
  290 /*
  291  * Common code for readv and preadv that reads data in
  292  * from a file using the passed in uio, offset, and flags.
  293  */
  294 static int
  295 dofileread(td, fd, fp, auio, offset, flags)
  296         struct thread *td;
  297         int fd;
  298         struct file *fp;
  299         struct uio *auio;
  300         off_t offset;
  301         int flags;
  302 {
  303         ssize_t cnt;
  304         int error;
  305 #ifdef KTRACE
  306         struct uio *ktruio = NULL;
  307 #endif
  308 
  309         /* Finish zero length reads right here */
  310         if (auio->uio_resid == 0) {
  311                 td->td_retval[0] = 0;
  312                 return(0);
  313         }
  314         auio->uio_rw = UIO_READ;
  315         auio->uio_offset = offset;
  316         auio->uio_td = td;
  317 #ifdef KTRACE
  318         if (KTRPOINT(td, KTR_GENIO)) 
  319                 ktruio = cloneuio(auio);
  320 #endif
  321         cnt = auio->uio_resid;
  322         if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) {
  323                 if (auio->uio_resid != cnt && (error == ERESTART ||
  324                     error == EINTR || error == EWOULDBLOCK))
  325                         error = 0;
  326         }
  327         cnt -= auio->uio_resid;
  328 #ifdef KTRACE
  329         if (ktruio != NULL) {
  330                 ktruio->uio_resid = cnt;
  331                 ktrgenio(fd, UIO_READ, ktruio, error);
  332         }
  333 #endif
  334         td->td_retval[0] = cnt;
  335         return (error);
  336 }
  337 
  338 #ifndef _SYS_SYSPROTO_H_
  339 struct write_args {
  340         int     fd;
  341         const void *buf;
  342         size_t  nbyte;
  343 };
  344 #endif
  345 int
  346 write(td, uap)
  347         struct thread *td;
  348         struct write_args *uap;
  349 {
  350         struct uio auio;
  351         struct iovec aiov;
  352         int error;
  353 
  354         if (uap->nbyte > INT_MAX)
  355                 return (EINVAL);
  356         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  357         aiov.iov_len = uap->nbyte;
  358         auio.uio_iov = &aiov;
  359         auio.uio_iovcnt = 1;
  360         auio.uio_resid = uap->nbyte;
  361         auio.uio_segflg = UIO_USERSPACE;
  362         error = kern_writev(td, uap->fd, &auio);
  363         return(error);
  364 }
  365 
  366 /*
  367  * Positioned write system call.
  368  */
  369 #ifndef _SYS_SYSPROTO_H_
  370 struct pwrite_args {
  371         int     fd;
  372         const void *buf;
  373         size_t  nbyte;
  374         int     pad;
  375         off_t   offset;
  376 };
  377 #endif
  378 int
  379 pwrite(td, uap)
  380         struct thread *td;
  381         struct pwrite_args *uap;
  382 {
  383         struct uio auio;
  384         struct iovec aiov;
  385         int error;
  386 
  387         if (uap->nbyte > INT_MAX)
  388                 return (EINVAL);
  389         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  390         aiov.iov_len = uap->nbyte;
  391         auio.uio_iov = &aiov;
  392         auio.uio_iovcnt = 1;
  393         auio.uio_resid = uap->nbyte;
  394         auio.uio_segflg = UIO_USERSPACE;
  395         error = kern_pwritev(td, uap->fd, &auio, uap->offset);
  396         return(error);
  397 }
  398 
  399 int
  400 freebsd6_pwrite(td, uap)
  401         struct thread *td;
  402         struct freebsd6_pwrite_args *uap;
  403 {
  404         struct pwrite_args oargs;
  405 
  406         oargs.fd = uap->fd;
  407         oargs.buf = uap->buf;
  408         oargs.nbyte = uap->nbyte;
  409         oargs.offset = uap->offset;
  410         return (pwrite(td, &oargs));
  411 }
  412 
  413 /*
  414  * Gather write system call.
  415  */
  416 #ifndef _SYS_SYSPROTO_H_
  417 struct writev_args {
  418         int     fd;
  419         struct  iovec *iovp;
  420         u_int   iovcnt;
  421 };
  422 #endif
  423 int
  424 writev(struct thread *td, struct writev_args *uap)
  425 {
  426         struct uio *auio;
  427         int error;
  428 
  429         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  430         if (error)
  431                 return (error);
  432         error = kern_writev(td, uap->fd, auio);
  433         free(auio, M_IOV);
  434         return (error);
  435 }
  436 
  437 int
  438 kern_writev(struct thread *td, int fd, struct uio *auio)
  439 {
  440         struct file *fp;
  441         int error;
  442 
  443         error = fget_write(td, fd, &fp);
  444         if (error)
  445                 return (error);
  446         error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0);
  447         fdrop(fp, td);
  448         return (error);
  449 }
  450 
  451 /*
  452  * Gather positioned write system call.
  453  */
  454 #ifndef _SYS_SYSPROTO_H_
  455 struct pwritev_args {
  456         int     fd;
  457         struct  iovec *iovp;
  458         u_int   iovcnt;
  459         off_t   offset;
  460 };
  461 #endif
  462 int
  463 pwritev(struct thread *td, struct pwritev_args *uap)
  464 {
  465         struct uio *auio;
  466         int error;
  467 
  468         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  469         if (error)
  470                 return (error);
  471         error = kern_pwritev(td, uap->fd, auio, uap->offset);
  472         free(auio, M_IOV);
  473         return (error);
  474 }
  475 
  476 int
  477 kern_pwritev(td, fd, auio, offset)
  478         struct thread *td;
  479         struct uio *auio;
  480         int fd;
  481         off_t offset;
  482 {
  483         struct file *fp;
  484         int error;
  485 
  486         error = fget_write(td, fd, &fp);
  487         if (error)
  488                 return (error);
  489         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  490                 error = ESPIPE;
  491         else if (offset < 0 && fp->f_vnode->v_type != VCHR)
  492                 error = EINVAL;
  493         else
  494                 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET);
  495         fdrop(fp, td);
  496         return (error);
  497 }
  498 
  499 /*
  500  * Common code for writev and pwritev that writes data to
  501  * a file using the passed in uio, offset, and flags.
  502  */
  503 static int
  504 dofilewrite(td, fd, fp, auio, offset, flags)
  505         struct thread *td;
  506         int fd;
  507         struct file *fp;
  508         struct uio *auio;
  509         off_t offset;
  510         int flags;
  511 {
  512         ssize_t cnt;
  513         int error;
  514 #ifdef KTRACE
  515         struct uio *ktruio = NULL;
  516 #endif
  517 
  518         auio->uio_rw = UIO_WRITE;
  519         auio->uio_td = td;
  520         auio->uio_offset = offset;
  521 #ifdef KTRACE
  522         if (KTRPOINT(td, KTR_GENIO))
  523                 ktruio = cloneuio(auio);
  524 #endif
  525         cnt = auio->uio_resid;
  526         if (fp->f_type == DTYPE_VNODE)
  527                 bwillwrite();
  528         if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) {
  529                 if (auio->uio_resid != cnt && (error == ERESTART ||
  530                     error == EINTR || error == EWOULDBLOCK))
  531                         error = 0;
  532                 /* Socket layer is responsible for issuing SIGPIPE. */
  533                 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) {
  534                         PROC_LOCK(td->td_proc);
  535                         psignal(td->td_proc, SIGPIPE);
  536                         PROC_UNLOCK(td->td_proc);
  537                 }
  538         }
  539         cnt -= auio->uio_resid;
  540 #ifdef KTRACE
  541         if (ktruio != NULL) {
  542                 ktruio->uio_resid = cnt;
  543                 ktrgenio(fd, UIO_WRITE, ktruio, error);
  544         }
  545 #endif
  546         td->td_retval[0] = cnt;
  547         return (error);
  548 }
  549 
  550 /*
  551  * Truncate a file given a file descriptor.
  552  *
  553  * Can't use fget_write() here, since must return EINVAL and not EBADF if the
  554  * descriptor isn't writable.
  555  */
  556 int
  557 kern_ftruncate(td, fd, length)
  558         struct thread *td;
  559         int fd;
  560         off_t length;
  561 {
  562         struct file *fp;
  563         int error;
  564 
  565         AUDIT_ARG_FD(fd);
  566         if (length < 0)
  567                 return (EINVAL);
  568         error = fget(td, fd, &fp);
  569         if (error)
  570                 return (error);
  571         AUDIT_ARG_FILE(td->td_proc, fp);
  572         if (!(fp->f_flag & FWRITE)) {
  573                 fdrop(fp, td);
  574                 return (EINVAL);
  575         }
  576         error = fo_truncate(fp, length, td->td_ucred, td);
  577         fdrop(fp, td);
  578         return (error);
  579 }
  580 
  581 #ifndef _SYS_SYSPROTO_H_
  582 struct ftruncate_args {
  583         int     fd;
  584         int     pad;
  585         off_t   length;
  586 };
  587 #endif
  588 int
  589 ftruncate(td, uap)
  590         struct thread *td;
  591         struct ftruncate_args *uap;
  592 {
  593 
  594         return (kern_ftruncate(td, uap->fd, uap->length));
  595 }
  596 
  597 #if defined(COMPAT_43)
  598 #ifndef _SYS_SYSPROTO_H_
  599 struct oftruncate_args {
  600         int     fd;
  601         long    length;
  602 };
  603 #endif
  604 int
  605 oftruncate(td, uap)
  606         struct thread *td;
  607         struct oftruncate_args *uap;
  608 {
  609 
  610         return (kern_ftruncate(td, uap->fd, uap->length));
  611 }
  612 #endif /* COMPAT_43 */
  613 
  614 #ifndef _SYS_SYSPROTO_H_
  615 struct ioctl_args {
  616         int     fd;
  617         u_long  com;
  618         caddr_t data;
  619 };
  620 #endif
  621 /* ARGSUSED */
  622 int
  623 ioctl(struct thread *td, struct ioctl_args *uap)
  624 {
  625         u_long com;
  626         int arg, error;
  627         u_int size;
  628         caddr_t data;
  629 
  630         if (uap->com > 0xffffffff) {
  631                 printf(
  632                     "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
  633                     td->td_proc->p_pid, td->td_name, uap->com);
  634                 uap->com &= 0xffffffff;
  635         }
  636         com = uap->com;
  637 
  638         /*
  639          * Interpret high order word to find amount of data to be
  640          * copied to/from the user's address space.
  641          */
  642         size = IOCPARM_LEN(com);
  643         if ((size > IOCPARM_MAX) ||
  644             ((com & (IOC_VOID  | IOC_IN | IOC_OUT)) == 0) ||
  645 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
  646             ((com & IOC_OUT) && size == 0) ||
  647 #else
  648             ((com & (IOC_IN | IOC_OUT)) && size == 0) ||
  649 #endif
  650             ((com & IOC_VOID) && size > 0 && size != sizeof(int)))
  651                 return (ENOTTY);
  652 
  653         if (size > 0) {
  654                 if (com & IOC_VOID) {
  655                         /* Integer argument. */
  656                         arg = (intptr_t)uap->data;
  657                         data = (void *)&arg;
  658                         size = 0;
  659                 } else
  660                         data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
  661         } else
  662                 data = (void *)&uap->data;
  663         if (com & IOC_IN) {
  664                 error = copyin(uap->data, data, (u_int)size);
  665                 if (error) {
  666                         if (size > 0)
  667                                 free(data, M_IOCTLOPS);
  668                         return (error);
  669                 }
  670         } else if (com & IOC_OUT) {
  671                 /*
  672                  * Zero the buffer so the user always
  673                  * gets back something deterministic.
  674                  */
  675                 bzero(data, size);
  676         }
  677 
  678         error = kern_ioctl(td, uap->fd, com, data);
  679 
  680         if (error == 0 && (com & IOC_OUT))
  681                 error = copyout(data, uap->data, (u_int)size);
  682 
  683         if (size > 0)
  684                 free(data, M_IOCTLOPS);
  685         return (error);
  686 }
  687 
  688 int
  689 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
  690 {
  691         struct file *fp;
  692         struct filedesc *fdp;
  693         int error;
  694         int tmp;
  695 
  696         AUDIT_ARG_FD(fd);
  697         AUDIT_ARG_CMD(com);
  698         if ((error = fget(td, fd, &fp)) != 0)
  699                 return (error);
  700         if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
  701                 fdrop(fp, td);
  702                 return (EBADF);
  703         }
  704         fdp = td->td_proc->p_fd;
  705         switch (com) {
  706         case FIONCLEX:
  707                 FILEDESC_XLOCK(fdp);
  708                 fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE;
  709                 FILEDESC_XUNLOCK(fdp);
  710                 goto out;
  711         case FIOCLEX:
  712                 FILEDESC_XLOCK(fdp);
  713                 fdp->fd_ofileflags[fd] |= UF_EXCLOSE;
  714                 FILEDESC_XUNLOCK(fdp);
  715                 goto out;
  716         case FIONBIO:
  717                 if ((tmp = *(int *)data))
  718                         atomic_set_int(&fp->f_flag, FNONBLOCK);
  719                 else
  720                         atomic_clear_int(&fp->f_flag, FNONBLOCK);
  721                 data = (void *)&tmp;
  722                 break;
  723         case FIOASYNC:
  724                 if ((tmp = *(int *)data))
  725                         atomic_set_int(&fp->f_flag, FASYNC);
  726                 else
  727                         atomic_clear_int(&fp->f_flag, FASYNC);
  728                 data = (void *)&tmp;
  729                 break;
  730         }
  731 
  732         error = fo_ioctl(fp, com, data, td->td_ucred, td);
  733 out:
  734         fdrop(fp, td);
  735         return (error);
  736 }
  737 
  738 int
  739 poll_no_poll(int events)
  740 {
  741         /*
  742          * Return true for read/write.  If the user asked for something
  743          * special, return POLLNVAL, so that clients have a way of
  744          * determining reliably whether or not the extended
  745          * functionality is present without hard-coding knowledge
  746          * of specific filesystem implementations.
  747          */
  748         if (events & ~POLLSTANDARD)
  749                 return (POLLNVAL);
  750 
  751         return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
  752 }
  753 
  754 int
  755 pselect(struct thread *td, struct pselect_args *uap)
  756 {
  757         struct timespec ts;
  758         struct timeval tv, *tvp;
  759         sigset_t set, *uset;
  760         int error;
  761 
  762         if (uap->ts != NULL) {
  763                 error = copyin(uap->ts, &ts, sizeof(ts));
  764                 if (error != 0)
  765                     return (error);
  766                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
  767                 tvp = &tv;
  768         } else
  769                 tvp = NULL;
  770         if (uap->sm != NULL) {
  771                 error = copyin(uap->sm, &set, sizeof(set));
  772                 if (error != 0)
  773                         return (error);
  774                 uset = &set;
  775         } else
  776                 uset = NULL;
  777         return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  778             uset, NFDBITS));
  779 }
  780 
  781 int
  782 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
  783     struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
  784 {
  785         int error;
  786 
  787         if (uset != NULL) {
  788                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
  789                     &td->td_oldsigmask, 0);
  790                 if (error != 0)
  791                         return (error);
  792                 td->td_pflags |= TDP_OLDMASK;
  793                 /*
  794                  * Make sure that ast() is called on return to
  795                  * usermode and TDP_OLDMASK is cleared, restoring old
  796                  * sigmask.
  797                  */
  798                 thread_lock(td);
  799                 td->td_flags |= TDF_ASTPENDING;
  800                 thread_unlock(td);
  801         }
  802         error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
  803         return (error);
  804 }
  805 
  806 #ifndef _SYS_SYSPROTO_H_
  807 struct select_args {
  808         int     nd;
  809         fd_set  *in, *ou, *ex;
  810         struct  timeval *tv;
  811 };
  812 #endif
  813 int
  814 select(struct thread *td, struct select_args *uap)
  815 {
  816         struct timeval tv, *tvp;
  817         int error;
  818 
  819         if (uap->tv != NULL) {
  820                 error = copyin(uap->tv, &tv, sizeof(tv));
  821                 if (error)
  822                         return (error);
  823                 tvp = &tv;
  824         } else
  825                 tvp = NULL;
  826 
  827         return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  828             NFDBITS));
  829 }
  830 
  831 int
  832 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
  833     fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
  834 {
  835         struct filedesc *fdp;
  836         /*
  837          * The magic 2048 here is chosen to be just enough for FD_SETSIZE
  838          * infds with the new FD_SETSIZE of 1024, and more than enough for
  839          * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
  840          * of 256.
  841          */
  842         fd_mask s_selbits[howmany(2048, NFDBITS)];
  843         fd_mask *ibits[3], *obits[3], *selbits, *sbp;
  844         struct timeval atv, rtv, ttv;
  845         int error, timo;
  846         u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
  847 
  848         if (nd < 0)
  849                 return (EINVAL);
  850         fdp = td->td_proc->p_fd;
  851         if (nd > fdp->fd_lastfile + 1)
  852                 nd = fdp->fd_lastfile + 1;
  853 
  854         /*
  855          * Allocate just enough bits for the non-null fd_sets.  Use the
  856          * preallocated auto buffer if possible.
  857          */
  858         nfdbits = roundup(nd, NFDBITS);
  859         ncpbytes = nfdbits / NBBY;
  860         ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
  861         nbufbytes = 0;
  862         if (fd_in != NULL)
  863                 nbufbytes += 2 * ncpbytes;
  864         if (fd_ou != NULL)
  865                 nbufbytes += 2 * ncpbytes;
  866         if (fd_ex != NULL)
  867                 nbufbytes += 2 * ncpbytes;
  868         if (nbufbytes <= sizeof s_selbits)
  869                 selbits = &s_selbits[0];
  870         else
  871                 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
  872 
  873         /*
  874          * Assign pointers into the bit buffers and fetch the input bits.
  875          * Put the output buffers together so that they can be bzeroed
  876          * together.
  877          */
  878         sbp = selbits;
  879 #define getbits(name, x) \
  880         do {                                                            \
  881                 if (name == NULL) {                                     \
  882                         ibits[x] = NULL;                                \
  883                         obits[x] = NULL;                                \
  884                 } else {                                                \
  885                         ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp;   \
  886                         obits[x] = sbp;                                 \
  887                         sbp += ncpbytes / sizeof *sbp;                  \
  888                         error = copyin(name, ibits[x], ncpubytes);      \
  889                         if (error != 0)                                 \
  890                                 goto done;                              \
  891                         bzero((char *)ibits[x] + ncpubytes,             \
  892                             ncpbytes - ncpubytes);                      \
  893                 }                                                       \
  894         } while (0)
  895         getbits(fd_in, 0);
  896         getbits(fd_ou, 1);
  897         getbits(fd_ex, 2);
  898 #undef  getbits
  899 
  900 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
  901         /*
  902          * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
  903          * we are running under 32-bit emulation. This should be more
  904          * generic.
  905          */
  906 #define swizzle_fdset(bits)                                             \
  907         if (abi_nfdbits != NFDBITS && bits != NULL) {                   \
  908                 int i;                                                  \
  909                 for (i = 0; i < ncpbytes / sizeof *sbp; i++)            \
  910                         bits[i] = (bits[i] >> 32) | (bits[i] << 32);    \
  911         }
  912 #else
  913 #define swizzle_fdset(bits)
  914 #endif
  915 
  916         /* Make sure the bit order makes it through an ABI transition */
  917         swizzle_fdset(ibits[0]);
  918         swizzle_fdset(ibits[1]);
  919         swizzle_fdset(ibits[2]);
  920         
  921         if (nbufbytes != 0)
  922                 bzero(selbits, nbufbytes / 2);
  923 
  924         if (tvp != NULL) {
  925                 atv = *tvp;
  926                 if (itimerfix(&atv)) {
  927                         error = EINVAL;
  928                         goto done;
  929                 }
  930                 getmicrouptime(&rtv);
  931                 timevaladd(&atv, &rtv);
  932         } else {
  933                 atv.tv_sec = 0;
  934                 atv.tv_usec = 0;
  935         }
  936         timo = 0;
  937         seltdinit(td);
  938         /* Iterate until the timeout expires or descriptors become ready. */
  939         for (;;) {
  940                 error = selscan(td, ibits, obits, nd);
  941                 if (error || td->td_retval[0] != 0)
  942                         break;
  943                 if (atv.tv_sec || atv.tv_usec) {
  944                         getmicrouptime(&rtv);
  945                         if (timevalcmp(&rtv, &atv, >=))
  946                                 break;
  947                         ttv = atv;
  948                         timevalsub(&ttv, &rtv);
  949                         timo = ttv.tv_sec > 24 * 60 * 60 ?
  950                             24 * 60 * 60 * hz : tvtohz(&ttv);
  951                 }
  952                 error = seltdwait(td, timo);
  953                 if (error)
  954                         break;
  955                 error = selrescan(td, ibits, obits);
  956                 if (error || td->td_retval[0] != 0)
  957                         break;
  958         }
  959         seltdclear(td);
  960 
  961 done:
  962         /* select is not restarted after signals... */
  963         if (error == ERESTART)
  964                 error = EINTR;
  965         if (error == EWOULDBLOCK)
  966                 error = 0;
  967 
  968         /* swizzle bit order back, if necessary */
  969         swizzle_fdset(obits[0]);
  970         swizzle_fdset(obits[1]);
  971         swizzle_fdset(obits[2]);
  972 #undef swizzle_fdset
  973 
  974 #define putbits(name, x) \
  975         if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
  976                 error = error2;
  977         if (error == 0) {
  978                 int error2;
  979 
  980                 putbits(fd_in, 0);
  981                 putbits(fd_ou, 1);
  982                 putbits(fd_ex, 2);
  983 #undef putbits
  984         }
  985         if (selbits != &s_selbits[0])
  986                 free(selbits, M_SELECT);
  987 
  988         return (error);
  989 }
  990 /* 
  991  * Convert a select bit set to poll flags.
  992  *
  993  * The backend always returns POLLHUP/POLLERR if appropriate and we
  994  * return this as a set bit in any set.
  995  */
  996 static int select_flags[3] = {
  997     POLLRDNORM | POLLHUP | POLLERR,
  998     POLLWRNORM | POLLHUP | POLLERR,
  999     POLLRDBAND | POLLERR
 1000 };
 1001 
 1002 /*
 1003  * Compute the fo_poll flags required for a fd given by the index and
 1004  * bit position in the fd_mask array.
 1005  */
 1006 static __inline int
 1007 selflags(fd_mask **ibits, int idx, fd_mask bit)
 1008 {
 1009         int flags;
 1010         int msk;
 1011 
 1012         flags = 0;
 1013         for (msk = 0; msk < 3; msk++) {
 1014                 if (ibits[msk] == NULL)
 1015                         continue;
 1016                 if ((ibits[msk][idx] & bit) == 0)
 1017                         continue;
 1018                 flags |= select_flags[msk];
 1019         }
 1020         return (flags);
 1021 }
 1022 
 1023 /*
 1024  * Set the appropriate output bits given a mask of fired events and the
 1025  * input bits originally requested.
 1026  */
 1027 static __inline int
 1028 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
 1029 {
 1030         int msk;
 1031         int n;
 1032 
 1033         n = 0;
 1034         for (msk = 0; msk < 3; msk++) {
 1035                 if ((events & select_flags[msk]) == 0)
 1036                         continue;
 1037                 if (ibits[msk] == NULL)
 1038                         continue;
 1039                 if ((ibits[msk][idx] & bit) == 0)
 1040                         continue;
 1041                 /*
 1042                  * XXX Check for a duplicate set.  This can occur because a
 1043                  * socket calls selrecord() twice for each poll() call
 1044                  * resulting in two selfds per real fd.  selrescan() will
 1045                  * call selsetbits twice as a result.
 1046                  */
 1047                 if ((obits[msk][idx] & bit) != 0)
 1048                         continue;
 1049                 obits[msk][idx] |= bit;
 1050                 n++;
 1051         }
 1052 
 1053         return (n);
 1054 }
 1055 
 1056 /*
 1057  * Traverse the list of fds attached to this thread's seltd and check for
 1058  * completion.
 1059  */
 1060 static int
 1061 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
 1062 {
 1063         struct filedesc *fdp;
 1064         struct selinfo *si;
 1065         struct seltd *stp;
 1066         struct selfd *sfp;
 1067         struct selfd *sfn;
 1068         struct file *fp;
 1069         fd_mask bit;
 1070         int fd, ev, n, idx;
 1071 
 1072         fdp = td->td_proc->p_fd;
 1073         stp = td->td_sel;
 1074         n = 0;
 1075         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1076                 fd = (int)(uintptr_t)sfp->sf_cookie;
 1077                 si = sfp->sf_si;
 1078                 selfdfree(stp, sfp);
 1079                 /* If the selinfo wasn't cleared the event didn't fire. */
 1080                 if (si != NULL)
 1081                         continue;
 1082                 if ((fp = fget_unlocked(fdp, fd)) == NULL)
 1083                         return (EBADF);
 1084                 idx = fd / NFDBITS;
 1085                 bit = (fd_mask)1 << (fd % NFDBITS);
 1086                 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
 1087                 fdrop(fp, td);
 1088                 if (ev != 0)
 1089                         n += selsetbits(ibits, obits, idx, bit, ev);
 1090         }
 1091         stp->st_flags = 0;
 1092         td->td_retval[0] = n;
 1093         return (0);
 1094 }
 1095 
 1096 /*
 1097  * Perform the initial filedescriptor scan and register ourselves with
 1098  * each selinfo.
 1099  */
 1100 static int
 1101 selscan(td, ibits, obits, nfd)
 1102         struct thread *td;
 1103         fd_mask **ibits, **obits;
 1104         int nfd;
 1105 {
 1106         struct filedesc *fdp;
 1107         struct file *fp;
 1108         fd_mask bit;
 1109         int ev, flags, end, fd;
 1110         int n, idx;
 1111 
 1112         fdp = td->td_proc->p_fd;
 1113         n = 0;
 1114         for (idx = 0, fd = 0; fd < nfd; idx++) {
 1115                 end = imin(fd + NFDBITS, nfd);
 1116                 for (bit = 1; fd < end; bit <<= 1, fd++) {
 1117                         /* Compute the list of events we're interested in. */
 1118                         flags = selflags(ibits, idx, bit);
 1119                         if (flags == 0)
 1120                                 continue;
 1121                         if ((fp = fget_unlocked(fdp, fd)) == NULL)
 1122                                 return (EBADF);
 1123                         selfdalloc(td, (void *)(uintptr_t)fd);
 1124                         ev = fo_poll(fp, flags, td->td_ucred, td);
 1125                         fdrop(fp, td);
 1126                         if (ev != 0)
 1127                                 n += selsetbits(ibits, obits, idx, bit, ev);
 1128                 }
 1129         }
 1130 
 1131         td->td_retval[0] = n;
 1132         return (0);
 1133 }
 1134 
 1135 #ifndef _SYS_SYSPROTO_H_
 1136 struct poll_args {
 1137         struct pollfd *fds;
 1138         u_int   nfds;
 1139         int     timeout;
 1140 };
 1141 #endif
 1142 int
 1143 poll(td, uap)
 1144         struct thread *td;
 1145         struct poll_args *uap;
 1146 {
 1147         struct pollfd *bits;
 1148         struct pollfd smallbits[32];
 1149         struct timeval atv, rtv, ttv;
 1150         int error = 0, timo;
 1151         u_int nfds;
 1152         size_t ni;
 1153 
 1154         nfds = uap->nfds;
 1155         if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 
 1156                 return (EINVAL);
 1157         ni = nfds * sizeof(struct pollfd);
 1158         if (ni > sizeof(smallbits))
 1159                 bits = malloc(ni, M_TEMP, M_WAITOK);
 1160         else
 1161                 bits = smallbits;
 1162         error = copyin(uap->fds, bits, ni);
 1163         if (error)
 1164                 goto done;
 1165         if (uap->timeout != INFTIM) {
 1166                 atv.tv_sec = uap->timeout / 1000;
 1167                 atv.tv_usec = (uap->timeout % 1000) * 1000;
 1168                 if (itimerfix(&atv)) {
 1169                         error = EINVAL;
 1170                         goto done;
 1171                 }
 1172                 getmicrouptime(&rtv);
 1173                 timevaladd(&atv, &rtv);
 1174         } else {
 1175                 atv.tv_sec = 0;
 1176                 atv.tv_usec = 0;
 1177         }
 1178         timo = 0;
 1179         seltdinit(td);
 1180         /* Iterate until the timeout expires or descriptors become ready. */
 1181         for (;;) {
 1182                 error = pollscan(td, bits, nfds);
 1183                 if (error || td->td_retval[0] != 0)
 1184                         break;
 1185                 if (atv.tv_sec || atv.tv_usec) {
 1186                         getmicrouptime(&rtv);
 1187                         if (timevalcmp(&rtv, &atv, >=))
 1188                                 break;
 1189                         ttv = atv;
 1190                         timevalsub(&ttv, &rtv);
 1191                         timo = ttv.tv_sec > 24 * 60 * 60 ?
 1192                             24 * 60 * 60 * hz : tvtohz(&ttv);
 1193                 }
 1194                 error = seltdwait(td, timo);
 1195                 if (error)
 1196                         break;
 1197                 error = pollrescan(td);
 1198                 if (error || td->td_retval[0] != 0)
 1199                         break;
 1200         }
 1201         seltdclear(td);
 1202 
 1203 done:
 1204         /* poll is not restarted after signals... */
 1205         if (error == ERESTART)
 1206                 error = EINTR;
 1207         if (error == EWOULDBLOCK)
 1208                 error = 0;
 1209         if (error == 0) {
 1210                 error = pollout(bits, uap->fds, nfds);
 1211                 if (error)
 1212                         goto out;
 1213         }
 1214 out:
 1215         if (ni > sizeof(smallbits))
 1216                 free(bits, M_TEMP);
 1217         return (error);
 1218 }
 1219 
 1220 static int
 1221 pollrescan(struct thread *td)
 1222 {
 1223         struct seltd *stp;
 1224         struct selfd *sfp;
 1225         struct selfd *sfn;
 1226         struct selinfo *si;
 1227         struct filedesc *fdp;
 1228         struct file *fp;
 1229         struct pollfd *fd;
 1230         int n;
 1231 
 1232         n = 0;
 1233         fdp = td->td_proc->p_fd;
 1234         stp = td->td_sel;
 1235         FILEDESC_SLOCK(fdp);
 1236         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1237                 fd = (struct pollfd *)sfp->sf_cookie;
 1238                 si = sfp->sf_si;
 1239                 selfdfree(stp, sfp);
 1240                 /* If the selinfo wasn't cleared the event didn't fire. */
 1241                 if (si != NULL)
 1242                         continue;
 1243                 fp = fdp->fd_ofiles[fd->fd];
 1244                 if (fp == NULL) {
 1245                         fd->revents = POLLNVAL;
 1246                         n++;
 1247                         continue;
 1248                 }
 1249                 /*
 1250                  * Note: backend also returns POLLHUP and
 1251                  * POLLERR if appropriate.
 1252                  */
 1253                 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
 1254                 if (fd->revents != 0)
 1255                         n++;
 1256         }
 1257         FILEDESC_SUNLOCK(fdp);
 1258         stp->st_flags = 0;
 1259         td->td_retval[0] = n;
 1260         return (0);
 1261 }
 1262 
 1263 
 1264 static int
 1265 pollout(fds, ufds, nfd)
 1266         struct pollfd *fds;
 1267         struct pollfd *ufds;
 1268         u_int nfd;
 1269 {
 1270         int error = 0;
 1271         u_int i = 0;
 1272 
 1273         for (i = 0; i < nfd; i++) {
 1274                 error = copyout(&fds->revents, &ufds->revents,
 1275                     sizeof(ufds->revents));
 1276                 if (error)
 1277                         return (error);
 1278                 fds++;
 1279                 ufds++;
 1280         }
 1281         return (0);
 1282 }
 1283 
 1284 static int
 1285 pollscan(td, fds, nfd)
 1286         struct thread *td;
 1287         struct pollfd *fds;
 1288         u_int nfd;
 1289 {
 1290         struct filedesc *fdp = td->td_proc->p_fd;
 1291         int i;
 1292         struct file *fp;
 1293         int n = 0;
 1294 
 1295         FILEDESC_SLOCK(fdp);
 1296         for (i = 0; i < nfd; i++, fds++) {
 1297                 if (fds->fd >= fdp->fd_nfiles) {
 1298                         fds->revents = POLLNVAL;
 1299                         n++;
 1300                 } else if (fds->fd < 0) {
 1301                         fds->revents = 0;
 1302                 } else {
 1303                         fp = fdp->fd_ofiles[fds->fd];
 1304                         if (fp == NULL) {
 1305                                 fds->revents = POLLNVAL;
 1306                                 n++;
 1307                         } else {
 1308                                 /*
 1309                                  * Note: backend also returns POLLHUP and
 1310                                  * POLLERR if appropriate.
 1311                                  */
 1312                                 selfdalloc(td, fds);
 1313                                 fds->revents = fo_poll(fp, fds->events,
 1314                                     td->td_ucred, td);
 1315                                 /*
 1316                                  * POSIX requires POLLOUT to be never
 1317                                  * set simultaneously with POLLHUP.
 1318                                  */
 1319                                 if ((fds->revents & POLLHUP) != 0)
 1320                                         fds->revents &= ~POLLOUT;
 1321 
 1322                                 if (fds->revents != 0)
 1323                                         n++;
 1324                         }
 1325                 }
 1326         }
 1327         FILEDESC_SUNLOCK(fdp);
 1328         td->td_retval[0] = n;
 1329         return (0);
 1330 }
 1331 
 1332 /*
 1333  * OpenBSD poll system call.
 1334  *
 1335  * XXX this isn't quite a true representation..  OpenBSD uses select ops.
 1336  */
 1337 #ifndef _SYS_SYSPROTO_H_
 1338 struct openbsd_poll_args {
 1339         struct pollfd *fds;
 1340         u_int   nfds;
 1341         int     timeout;
 1342 };
 1343 #endif
 1344 int
 1345 openbsd_poll(td, uap)
 1346         register struct thread *td;
 1347         register struct openbsd_poll_args *uap;
 1348 {
 1349         return (poll(td, (struct poll_args *)uap));
 1350 }
 1351 
 1352 /*
 1353  * XXX This was created specifically to support netncp and netsmb.  This
 1354  * allows the caller to specify a socket to wait for events on.  It returns
 1355  * 0 if any events matched and an error otherwise.  There is no way to
 1356  * determine which events fired.
 1357  */
 1358 int
 1359 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
 1360 {
 1361         struct timeval atv, rtv, ttv;
 1362         int error, timo;
 1363 
 1364         if (tvp != NULL) {
 1365                 atv = *tvp;
 1366                 if (itimerfix(&atv))
 1367                         return (EINVAL);
 1368                 getmicrouptime(&rtv);
 1369                 timevaladd(&atv, &rtv);
 1370         } else {
 1371                 atv.tv_sec = 0;
 1372                 atv.tv_usec = 0;
 1373         }
 1374 
 1375         timo = 0;
 1376         seltdinit(td);
 1377         /*
 1378          * Iterate until the timeout expires or the socket becomes ready.
 1379          */
 1380         for (;;) {
 1381                 selfdalloc(td, NULL);
 1382                 error = sopoll(so, events, NULL, td);
 1383                 /* error here is actually the ready events. */
 1384                 if (error)
 1385                         return (0);
 1386                 if (atv.tv_sec || atv.tv_usec) {
 1387                         getmicrouptime(&rtv);
 1388                         if (timevalcmp(&rtv, &atv, >=)) {
 1389                                 seltdclear(td);
 1390                                 return (EWOULDBLOCK);
 1391                         }
 1392                         ttv = atv;
 1393                         timevalsub(&ttv, &rtv);
 1394                         timo = ttv.tv_sec > 24 * 60 * 60 ?
 1395                             24 * 60 * 60 * hz : tvtohz(&ttv);
 1396                 }
 1397                 error = seltdwait(td, timo);
 1398                 seltdclear(td);
 1399                 if (error)
 1400                         break;
 1401         }
 1402         /* XXX Duplicates ncp/smb behavior. */
 1403         if (error == ERESTART)
 1404                 error = 0;
 1405         return (error);
 1406 }
 1407 
 1408 /*
 1409  * Preallocate two selfds associated with 'cookie'.  Some fo_poll routines
 1410  * have two select sets, one for read and another for write.
 1411  */
 1412 static void
 1413 selfdalloc(struct thread *td, void *cookie)
 1414 {
 1415         struct seltd *stp;
 1416 
 1417         stp = td->td_sel;
 1418         if (stp->st_free1 == NULL)
 1419                 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1420         stp->st_free1->sf_td = stp;
 1421         stp->st_free1->sf_cookie = cookie;
 1422         if (stp->st_free2 == NULL)
 1423                 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1424         stp->st_free2->sf_td = stp;
 1425         stp->st_free2->sf_cookie = cookie;
 1426 }
 1427 
 1428 static void
 1429 selfdfree(struct seltd *stp, struct selfd *sfp)
 1430 {
 1431         STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
 1432         mtx_lock(sfp->sf_mtx);
 1433         if (sfp->sf_si)
 1434                 TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
 1435         mtx_unlock(sfp->sf_mtx);
 1436         uma_zfree(selfd_zone, sfp);
 1437 }
 1438 
 1439 /*
 1440  * Record a select request.
 1441  */
 1442 void
 1443 selrecord(selector, sip)
 1444         struct thread *selector;
 1445         struct selinfo *sip;
 1446 {
 1447         struct selfd *sfp;
 1448         struct seltd *stp;
 1449         struct mtx *mtxp;
 1450 
 1451         stp = selector->td_sel;
 1452         /*
 1453          * Don't record when doing a rescan.
 1454          */
 1455         if (stp->st_flags & SELTD_RESCAN)
 1456                 return;
 1457         /*
 1458          * Grab one of the preallocated descriptors.
 1459          */
 1460         sfp = NULL;
 1461         if ((sfp = stp->st_free1) != NULL)
 1462                 stp->st_free1 = NULL;
 1463         else if ((sfp = stp->st_free2) != NULL)
 1464                 stp->st_free2 = NULL;
 1465         else
 1466                 panic("selrecord: No free selfd on selq");
 1467         mtxp = sip->si_mtx;
 1468         if (mtxp == NULL)
 1469                 mtxp = mtx_pool_find(mtxpool_select, sip);
 1470         /*
 1471          * Initialize the sfp and queue it in the thread.
 1472          */
 1473         sfp->sf_si = sip;
 1474         sfp->sf_mtx = mtxp;
 1475         STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
 1476         /*
 1477          * Now that we've locked the sip, check for initialization.
 1478          */
 1479         mtx_lock(mtxp);
 1480         if (sip->si_mtx == NULL) {
 1481                 sip->si_mtx = mtxp;
 1482                 TAILQ_INIT(&sip->si_tdlist);
 1483         }
 1484         /*
 1485          * Add this thread to the list of selfds listening on this selinfo.
 1486          */
 1487         TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
 1488         mtx_unlock(sip->si_mtx);
 1489 }
 1490 
 1491 /* Wake up a selecting thread. */
 1492 void
 1493 selwakeup(sip)
 1494         struct selinfo *sip;
 1495 {
 1496         doselwakeup(sip, -1);
 1497 }
 1498 
 1499 /* Wake up a selecting thread, and set its priority. */
 1500 void
 1501 selwakeuppri(sip, pri)
 1502         struct selinfo *sip;
 1503         int pri;
 1504 {
 1505         doselwakeup(sip, pri);
 1506 }
 1507 
 1508 /*
 1509  * Do a wakeup when a selectable event occurs.
 1510  */
 1511 static void
 1512 doselwakeup(sip, pri)
 1513         struct selinfo *sip;
 1514         int pri;
 1515 {
 1516         struct selfd *sfp;
 1517         struct selfd *sfn;
 1518         struct seltd *stp;
 1519 
 1520         /* If it's not initialized there can't be any waiters. */
 1521         if (sip->si_mtx == NULL)
 1522                 return;
 1523         /*
 1524          * Locking the selinfo locks all selfds associated with it.
 1525          */
 1526         mtx_lock(sip->si_mtx);
 1527         TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
 1528                 /*
 1529                  * Once we remove this sfp from the list and clear the
 1530                  * sf_si seltdclear will know to ignore this si.
 1531                  */
 1532                 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
 1533                 sfp->sf_si = NULL;
 1534                 stp = sfp->sf_td;
 1535                 mtx_lock(&stp->st_mtx);
 1536                 stp->st_flags |= SELTD_PENDING;
 1537                 cv_broadcastpri(&stp->st_wait, pri);
 1538                 mtx_unlock(&stp->st_mtx);
 1539         }
 1540         mtx_unlock(sip->si_mtx);
 1541 }
 1542 
 1543 static void
 1544 seltdinit(struct thread *td)
 1545 {
 1546         struct seltd *stp;
 1547 
 1548         if ((stp = td->td_sel) != NULL)
 1549                 goto out;
 1550         td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
 1551         mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
 1552         cv_init(&stp->st_wait, "select");
 1553 out:
 1554         stp->st_flags = 0;
 1555         STAILQ_INIT(&stp->st_selq);
 1556 }
 1557 
 1558 static int
 1559 seltdwait(struct thread *td, int timo)
 1560 {
 1561         struct seltd *stp;
 1562         int error;
 1563 
 1564         stp = td->td_sel;
 1565         /*
 1566          * An event of interest may occur while we do not hold the seltd
 1567          * locked so check the pending flag before we sleep.
 1568          */
 1569         mtx_lock(&stp->st_mtx);
 1570         /*
 1571          * Any further calls to selrecord will be a rescan.
 1572          */
 1573         stp->st_flags |= SELTD_RESCAN;
 1574         if (stp->st_flags & SELTD_PENDING) {
 1575                 mtx_unlock(&stp->st_mtx);
 1576                 return (0);
 1577         }
 1578         if (timo > 0)
 1579                 error = cv_timedwait_sig(&stp->st_wait, &stp->st_mtx, timo);
 1580         else
 1581                 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
 1582         mtx_unlock(&stp->st_mtx);
 1583 
 1584         return (error);
 1585 }
 1586 
 1587 void
 1588 seltdfini(struct thread *td)
 1589 {
 1590         struct seltd *stp;
 1591 
 1592         stp = td->td_sel;
 1593         if (stp == NULL)
 1594                 return;
 1595         if (stp->st_free1)
 1596                 uma_zfree(selfd_zone, stp->st_free1);
 1597         if (stp->st_free2)
 1598                 uma_zfree(selfd_zone, stp->st_free2);
 1599         td->td_sel = NULL;
 1600         free(stp, M_SELECT);
 1601 }
 1602 
 1603 /*
 1604  * Remove the references to the thread from all of the objects we were
 1605  * polling.
 1606  */
 1607 static void
 1608 seltdclear(struct thread *td)
 1609 {
 1610         struct seltd *stp;
 1611         struct selfd *sfp;
 1612         struct selfd *sfn;
 1613 
 1614         stp = td->td_sel;
 1615         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
 1616                 selfdfree(stp, sfp);
 1617         stp->st_flags = 0;
 1618 }
 1619 
 1620 static void selectinit(void *);
 1621 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
 1622 static void
 1623 selectinit(void *dummy __unused)
 1624 {
 1625 
 1626         selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
 1627             NULL, NULL, UMA_ALIGN_PTR, 0);
 1628         mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
 1629 }

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