The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kern/sys_generic.c

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1989, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)sys_generic.c       8.5 (Berkeley) 1/21/94
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD: releng/9.2/sys/kern/sys_generic.c 245103 2013-01-06 15:07:19Z kib $");
   39 
   40 #include "opt_capsicum.h"
   41 #include "opt_compat.h"
   42 #include "opt_ktrace.h"
   43 
   44 #include <sys/param.h>
   45 #include <sys/systm.h>
   46 #include <sys/sysproto.h>
   47 #include <sys/capability.h>
   48 #include <sys/filedesc.h>
   49 #include <sys/filio.h>
   50 #include <sys/fcntl.h>
   51 #include <sys/file.h>
   52 #include <sys/proc.h>
   53 #include <sys/signalvar.h>
   54 #include <sys/socketvar.h>
   55 #include <sys/uio.h>
   56 #include <sys/kernel.h>
   57 #include <sys/ktr.h>
   58 #include <sys/limits.h>
   59 #include <sys/malloc.h>
   60 #include <sys/poll.h>
   61 #include <sys/resourcevar.h>
   62 #include <sys/selinfo.h>
   63 #include <sys/sleepqueue.h>
   64 #include <sys/syscallsubr.h>
   65 #include <sys/sysctl.h>
   66 #include <sys/sysent.h>
   67 #include <sys/vnode.h>
   68 #include <sys/bio.h>
   69 #include <sys/buf.h>
   70 #include <sys/condvar.h>
   71 #ifdef KTRACE
   72 #include <sys/ktrace.h>
   73 #endif
   74 
   75 #include <security/audit/audit.h>
   76 
   77 int iosize_max_clamp = 1;
   78 SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW,
   79     &iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX");
   80 /*
   81  * Assert that the return value of read(2) and write(2) syscalls fits
   82  * into a register.  If not, an architecture will need to provide the
   83  * usermode wrappers to reconstruct the result.
   84  */
   85 CTASSERT(sizeof(register_t) >= sizeof(size_t));
   86 
   87 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer");
   88 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer");
   89 MALLOC_DEFINE(M_IOV, "iov", "large iov's");
   90 
   91 static int      pollout(struct thread *, struct pollfd *, struct pollfd *,
   92                     u_int);
   93 static int      pollscan(struct thread *, struct pollfd *, u_int);
   94 static int      pollrescan(struct thread *);
   95 static int      selscan(struct thread *, fd_mask **, fd_mask **, int);
   96 static int      selrescan(struct thread *, fd_mask **, fd_mask **);
   97 static void     selfdalloc(struct thread *, void *);
   98 static void     selfdfree(struct seltd *, struct selfd *);
   99 static int      dofileread(struct thread *, int, struct file *, struct uio *,
  100                     off_t, int);
  101 static int      dofilewrite(struct thread *, int, struct file *, struct uio *,
  102                     off_t, int);
  103 static void     doselwakeup(struct selinfo *, int);
  104 static void     seltdinit(struct thread *);
  105 static int      seltdwait(struct thread *, int);
  106 static void     seltdclear(struct thread *);
  107 
  108 /*
  109  * One seltd per-thread allocated on demand as needed.
  110  *
  111  *      t - protected by st_mtx
  112  *      k - Only accessed by curthread or read-only
  113  */
  114 struct seltd {
  115         STAILQ_HEAD(, selfd)    st_selq;        /* (k) List of selfds. */
  116         struct selfd            *st_free1;      /* (k) free fd for read set. */
  117         struct selfd            *st_free2;      /* (k) free fd for write set. */
  118         struct mtx              st_mtx;         /* Protects struct seltd */
  119         struct cv               st_wait;        /* (t) Wait channel. */
  120         int                     st_flags;       /* (t) SELTD_ flags. */
  121 };
  122 
  123 #define SELTD_PENDING   0x0001                  /* We have pending events. */
  124 #define SELTD_RESCAN    0x0002                  /* Doing a rescan. */
  125 
  126 /*
  127  * One selfd allocated per-thread per-file-descriptor.
  128  *      f - protected by sf_mtx
  129  */
  130 struct selfd {
  131         STAILQ_ENTRY(selfd)     sf_link;        /* (k) fds owned by this td. */
  132         TAILQ_ENTRY(selfd)      sf_threads;     /* (f) fds on this selinfo. */
  133         struct selinfo          *sf_si;         /* (f) selinfo when linked. */
  134         struct mtx              *sf_mtx;        /* Pointer to selinfo mtx. */
  135         struct seltd            *sf_td;         /* (k) owning seltd. */
  136         void                    *sf_cookie;     /* (k) fd or pollfd. */
  137 };
  138 
  139 static uma_zone_t selfd_zone;
  140 static struct mtx_pool *mtxpool_select;
  141 
  142 #ifndef _SYS_SYSPROTO_H_
  143 struct read_args {
  144         int     fd;
  145         void    *buf;
  146         size_t  nbyte;
  147 };
  148 #endif
  149 int
  150 sys_read(td, uap)
  151         struct thread *td;
  152         struct read_args *uap;
  153 {
  154         struct uio auio;
  155         struct iovec aiov;
  156         int error;
  157 
  158         if (uap->nbyte > IOSIZE_MAX)
  159                 return (EINVAL);
  160         aiov.iov_base = uap->buf;
  161         aiov.iov_len = uap->nbyte;
  162         auio.uio_iov = &aiov;
  163         auio.uio_iovcnt = 1;
  164         auio.uio_resid = uap->nbyte;
  165         auio.uio_segflg = UIO_USERSPACE;
  166         error = kern_readv(td, uap->fd, &auio);
  167         return(error);
  168 }
  169 
  170 /*
  171  * Positioned read system call
  172  */
  173 #ifndef _SYS_SYSPROTO_H_
  174 struct pread_args {
  175         int     fd;
  176         void    *buf;
  177         size_t  nbyte;
  178         int     pad;
  179         off_t   offset;
  180 };
  181 #endif
  182 int
  183 sys_pread(td, uap)
  184         struct thread *td;
  185         struct pread_args *uap;
  186 {
  187         struct uio auio;
  188         struct iovec aiov;
  189         int error;
  190 
  191         if (uap->nbyte > IOSIZE_MAX)
  192                 return (EINVAL);
  193         aiov.iov_base = uap->buf;
  194         aiov.iov_len = uap->nbyte;
  195         auio.uio_iov = &aiov;
  196         auio.uio_iovcnt = 1;
  197         auio.uio_resid = uap->nbyte;
  198         auio.uio_segflg = UIO_USERSPACE;
  199         error = kern_preadv(td, uap->fd, &auio, uap->offset);
  200         return(error);
  201 }
  202 
  203 int
  204 freebsd6_pread(td, uap)
  205         struct thread *td;
  206         struct freebsd6_pread_args *uap;
  207 {
  208         struct pread_args oargs;
  209 
  210         oargs.fd = uap->fd;
  211         oargs.buf = uap->buf;
  212         oargs.nbyte = uap->nbyte;
  213         oargs.offset = uap->offset;
  214         return (sys_pread(td, &oargs));
  215 }
  216 
  217 /*
  218  * Scatter read system call.
  219  */
  220 #ifndef _SYS_SYSPROTO_H_
  221 struct readv_args {
  222         int     fd;
  223         struct  iovec *iovp;
  224         u_int   iovcnt;
  225 };
  226 #endif
  227 int
  228 sys_readv(struct thread *td, struct readv_args *uap)
  229 {
  230         struct uio *auio;
  231         int error;
  232 
  233         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  234         if (error)
  235                 return (error);
  236         error = kern_readv(td, uap->fd, auio);
  237         free(auio, M_IOV);
  238         return (error);
  239 }
  240 
  241 int
  242 kern_readv(struct thread *td, int fd, struct uio *auio)
  243 {
  244         struct file *fp;
  245         int error;
  246 
  247         error = fget_read(td, fd, CAP_READ | CAP_SEEK, &fp);
  248         if (error)
  249                 return (error);
  250         error = dofileread(td, fd, fp, auio, (off_t)-1, 0);
  251         fdrop(fp, td);
  252         return (error);
  253 }
  254 
  255 /*
  256  * Scatter positioned read system call.
  257  */
  258 #ifndef _SYS_SYSPROTO_H_
  259 struct preadv_args {
  260         int     fd;
  261         struct  iovec *iovp;
  262         u_int   iovcnt;
  263         off_t   offset;
  264 };
  265 #endif
  266 int
  267 sys_preadv(struct thread *td, struct preadv_args *uap)
  268 {
  269         struct uio *auio;
  270         int error;
  271 
  272         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  273         if (error)
  274                 return (error);
  275         error = kern_preadv(td, uap->fd, auio, uap->offset);
  276         free(auio, M_IOV);
  277         return (error);
  278 }
  279 
  280 int
  281 kern_preadv(td, fd, auio, offset)
  282         struct thread *td;
  283         int fd;
  284         struct uio *auio;
  285         off_t offset;
  286 {
  287         struct file *fp;
  288         int error;
  289 
  290         error = fget_read(td, fd, CAP_READ, &fp);
  291         if (error)
  292                 return (error);
  293         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  294                 error = ESPIPE;
  295         else if (offset < 0 && fp->f_vnode->v_type != VCHR)
  296                 error = EINVAL;
  297         else
  298                 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET);
  299         fdrop(fp, td);
  300         return (error);
  301 }
  302 
  303 /*
  304  * Common code for readv and preadv that reads data in
  305  * from a file using the passed in uio, offset, and flags.
  306  */
  307 static int
  308 dofileread(td, fd, fp, auio, offset, flags)
  309         struct thread *td;
  310         int fd;
  311         struct file *fp;
  312         struct uio *auio;
  313         off_t offset;
  314         int flags;
  315 {
  316         ssize_t cnt;
  317         int error;
  318 #ifdef KTRACE
  319         struct uio *ktruio = NULL;
  320 #endif
  321 
  322         /* Finish zero length reads right here */
  323         if (auio->uio_resid == 0) {
  324                 td->td_retval[0] = 0;
  325                 return(0);
  326         }
  327         auio->uio_rw = UIO_READ;
  328         auio->uio_offset = offset;
  329         auio->uio_td = td;
  330 #ifdef KTRACE
  331         if (KTRPOINT(td, KTR_GENIO)) 
  332                 ktruio = cloneuio(auio);
  333 #endif
  334         cnt = auio->uio_resid;
  335         if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) {
  336                 if (auio->uio_resid != cnt && (error == ERESTART ||
  337                     error == EINTR || error == EWOULDBLOCK))
  338                         error = 0;
  339         }
  340         cnt -= auio->uio_resid;
  341 #ifdef KTRACE
  342         if (ktruio != NULL) {
  343                 ktruio->uio_resid = cnt;
  344                 ktrgenio(fd, UIO_READ, ktruio, error);
  345         }
  346 #endif
  347         td->td_retval[0] = cnt;
  348         return (error);
  349 }
  350 
  351 #ifndef _SYS_SYSPROTO_H_
  352 struct write_args {
  353         int     fd;
  354         const void *buf;
  355         size_t  nbyte;
  356 };
  357 #endif
  358 int
  359 sys_write(td, uap)
  360         struct thread *td;
  361         struct write_args *uap;
  362 {
  363         struct uio auio;
  364         struct iovec aiov;
  365         int error;
  366 
  367         if (uap->nbyte > IOSIZE_MAX)
  368                 return (EINVAL);
  369         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  370         aiov.iov_len = uap->nbyte;
  371         auio.uio_iov = &aiov;
  372         auio.uio_iovcnt = 1;
  373         auio.uio_resid = uap->nbyte;
  374         auio.uio_segflg = UIO_USERSPACE;
  375         error = kern_writev(td, uap->fd, &auio);
  376         return(error);
  377 }
  378 
  379 /*
  380  * Positioned write system call.
  381  */
  382 #ifndef _SYS_SYSPROTO_H_
  383 struct pwrite_args {
  384         int     fd;
  385         const void *buf;
  386         size_t  nbyte;
  387         int     pad;
  388         off_t   offset;
  389 };
  390 #endif
  391 int
  392 sys_pwrite(td, uap)
  393         struct thread *td;
  394         struct pwrite_args *uap;
  395 {
  396         struct uio auio;
  397         struct iovec aiov;
  398         int error;
  399 
  400         if (uap->nbyte > IOSIZE_MAX)
  401                 return (EINVAL);
  402         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  403         aiov.iov_len = uap->nbyte;
  404         auio.uio_iov = &aiov;
  405         auio.uio_iovcnt = 1;
  406         auio.uio_resid = uap->nbyte;
  407         auio.uio_segflg = UIO_USERSPACE;
  408         error = kern_pwritev(td, uap->fd, &auio, uap->offset);
  409         return(error);
  410 }
  411 
  412 int
  413 freebsd6_pwrite(td, uap)
  414         struct thread *td;
  415         struct freebsd6_pwrite_args *uap;
  416 {
  417         struct pwrite_args oargs;
  418 
  419         oargs.fd = uap->fd;
  420         oargs.buf = uap->buf;
  421         oargs.nbyte = uap->nbyte;
  422         oargs.offset = uap->offset;
  423         return (sys_pwrite(td, &oargs));
  424 }
  425 
  426 /*
  427  * Gather write system call.
  428  */
  429 #ifndef _SYS_SYSPROTO_H_
  430 struct writev_args {
  431         int     fd;
  432         struct  iovec *iovp;
  433         u_int   iovcnt;
  434 };
  435 #endif
  436 int
  437 sys_writev(struct thread *td, struct writev_args *uap)
  438 {
  439         struct uio *auio;
  440         int error;
  441 
  442         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  443         if (error)
  444                 return (error);
  445         error = kern_writev(td, uap->fd, auio);
  446         free(auio, M_IOV);
  447         return (error);
  448 }
  449 
  450 int
  451 kern_writev(struct thread *td, int fd, struct uio *auio)
  452 {
  453         struct file *fp;
  454         int error;
  455 
  456         error = fget_write(td, fd, CAP_WRITE | CAP_SEEK, &fp);
  457         if (error)
  458                 return (error);
  459         error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0);
  460         fdrop(fp, td);
  461         return (error);
  462 }
  463 
  464 /*
  465  * Gather positioned write system call.
  466  */
  467 #ifndef _SYS_SYSPROTO_H_
  468 struct pwritev_args {
  469         int     fd;
  470         struct  iovec *iovp;
  471         u_int   iovcnt;
  472         off_t   offset;
  473 };
  474 #endif
  475 int
  476 sys_pwritev(struct thread *td, struct pwritev_args *uap)
  477 {
  478         struct uio *auio;
  479         int error;
  480 
  481         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  482         if (error)
  483                 return (error);
  484         error = kern_pwritev(td, uap->fd, auio, uap->offset);
  485         free(auio, M_IOV);
  486         return (error);
  487 }
  488 
  489 int
  490 kern_pwritev(td, fd, auio, offset)
  491         struct thread *td;
  492         struct uio *auio;
  493         int fd;
  494         off_t offset;
  495 {
  496         struct file *fp;
  497         int error;
  498 
  499         error = fget_write(td, fd, CAP_WRITE, &fp);
  500         if (error)
  501                 return (error);
  502         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  503                 error = ESPIPE;
  504         else if (offset < 0 && fp->f_vnode->v_type != VCHR)
  505                 error = EINVAL;
  506         else
  507                 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET);
  508         fdrop(fp, td);
  509         return (error);
  510 }
  511 
  512 /*
  513  * Common code for writev and pwritev that writes data to
  514  * a file using the passed in uio, offset, and flags.
  515  */
  516 static int
  517 dofilewrite(td, fd, fp, auio, offset, flags)
  518         struct thread *td;
  519         int fd;
  520         struct file *fp;
  521         struct uio *auio;
  522         off_t offset;
  523         int flags;
  524 {
  525         ssize_t cnt;
  526         int error;
  527 #ifdef KTRACE
  528         struct uio *ktruio = NULL;
  529 #endif
  530 
  531         auio->uio_rw = UIO_WRITE;
  532         auio->uio_td = td;
  533         auio->uio_offset = offset;
  534 #ifdef KTRACE
  535         if (KTRPOINT(td, KTR_GENIO))
  536                 ktruio = cloneuio(auio);
  537 #endif
  538         cnt = auio->uio_resid;
  539         if (fp->f_type == DTYPE_VNODE &&
  540             (fp->f_vnread_flags & FDEVFS_VNODE) == 0)
  541                 bwillwrite();
  542         if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) {
  543                 if (auio->uio_resid != cnt && (error == ERESTART ||
  544                     error == EINTR || error == EWOULDBLOCK))
  545                         error = 0;
  546                 /* Socket layer is responsible for issuing SIGPIPE. */
  547                 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) {
  548                         PROC_LOCK(td->td_proc);
  549                         tdsignal(td, SIGPIPE);
  550                         PROC_UNLOCK(td->td_proc);
  551                 }
  552         }
  553         cnt -= auio->uio_resid;
  554 #ifdef KTRACE
  555         if (ktruio != NULL) {
  556                 ktruio->uio_resid = cnt;
  557                 ktrgenio(fd, UIO_WRITE, ktruio, error);
  558         }
  559 #endif
  560         td->td_retval[0] = cnt;
  561         return (error);
  562 }
  563 
  564 /*
  565  * Truncate a file given a file descriptor.
  566  *
  567  * Can't use fget_write() here, since must return EINVAL and not EBADF if the
  568  * descriptor isn't writable.
  569  */
  570 int
  571 kern_ftruncate(td, fd, length)
  572         struct thread *td;
  573         int fd;
  574         off_t length;
  575 {
  576         struct file *fp;
  577         int error;
  578 
  579         AUDIT_ARG_FD(fd);
  580         if (length < 0)
  581                 return (EINVAL);
  582         error = fget(td, fd, CAP_FTRUNCATE, &fp);
  583         if (error)
  584                 return (error);
  585         AUDIT_ARG_FILE(td->td_proc, fp);
  586         if (!(fp->f_flag & FWRITE)) {
  587                 fdrop(fp, td);
  588                 return (EINVAL);
  589         }
  590         error = fo_truncate(fp, length, td->td_ucred, td);
  591         fdrop(fp, td);
  592         return (error);
  593 }
  594 
  595 #ifndef _SYS_SYSPROTO_H_
  596 struct ftruncate_args {
  597         int     fd;
  598         int     pad;
  599         off_t   length;
  600 };
  601 #endif
  602 int
  603 sys_ftruncate(td, uap)
  604         struct thread *td;
  605         struct ftruncate_args *uap;
  606 {
  607 
  608         return (kern_ftruncate(td, uap->fd, uap->length));
  609 }
  610 
  611 #if defined(COMPAT_43)
  612 #ifndef _SYS_SYSPROTO_H_
  613 struct oftruncate_args {
  614         int     fd;
  615         long    length;
  616 };
  617 #endif
  618 int
  619 oftruncate(td, uap)
  620         struct thread *td;
  621         struct oftruncate_args *uap;
  622 {
  623 
  624         return (kern_ftruncate(td, uap->fd, uap->length));
  625 }
  626 #endif /* COMPAT_43 */
  627 
  628 #ifndef _SYS_SYSPROTO_H_
  629 struct ioctl_args {
  630         int     fd;
  631         u_long  com;
  632         caddr_t data;
  633 };
  634 #endif
  635 /* ARGSUSED */
  636 int
  637 sys_ioctl(struct thread *td, struct ioctl_args *uap)
  638 {
  639         u_long com;
  640         int arg, error;
  641         u_int size;
  642         caddr_t data;
  643 
  644         if (uap->com > 0xffffffff) {
  645                 printf(
  646                     "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
  647                     td->td_proc->p_pid, td->td_name, uap->com);
  648                 uap->com &= 0xffffffff;
  649         }
  650         com = uap->com;
  651 
  652         /*
  653          * Interpret high order word to find amount of data to be
  654          * copied to/from the user's address space.
  655          */
  656         size = IOCPARM_LEN(com);
  657         if ((size > IOCPARM_MAX) ||
  658             ((com & (IOC_VOID  | IOC_IN | IOC_OUT)) == 0) ||
  659 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
  660             ((com & IOC_OUT) && size == 0) ||
  661 #else
  662             ((com & (IOC_IN | IOC_OUT)) && size == 0) ||
  663 #endif
  664             ((com & IOC_VOID) && size > 0 && size != sizeof(int)))
  665                 return (ENOTTY);
  666 
  667         if (size > 0) {
  668                 if (com & IOC_VOID) {
  669                         /* Integer argument. */
  670                         arg = (intptr_t)uap->data;
  671                         data = (void *)&arg;
  672                         size = 0;
  673                 } else
  674                         data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
  675         } else
  676                 data = (void *)&uap->data;
  677         if (com & IOC_IN) {
  678                 error = copyin(uap->data, data, (u_int)size);
  679                 if (error) {
  680                         if (size > 0)
  681                                 free(data, M_IOCTLOPS);
  682                         return (error);
  683                 }
  684         } else if (com & IOC_OUT) {
  685                 /*
  686                  * Zero the buffer so the user always
  687                  * gets back something deterministic.
  688                  */
  689                 bzero(data, size);
  690         }
  691 
  692         error = kern_ioctl(td, uap->fd, com, data);
  693 
  694         if (error == 0 && (com & IOC_OUT))
  695                 error = copyout(data, uap->data, (u_int)size);
  696 
  697         if (size > 0)
  698                 free(data, M_IOCTLOPS);
  699         return (error);
  700 }
  701 
  702 int
  703 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
  704 {
  705         struct file *fp;
  706         struct filedesc *fdp;
  707         int error;
  708         int tmp;
  709 
  710         AUDIT_ARG_FD(fd);
  711         AUDIT_ARG_CMD(com);
  712         if ((error = fget(td, fd, CAP_IOCTL, &fp)) != 0)
  713                 return (error);
  714         if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
  715                 fdrop(fp, td);
  716                 return (EBADF);
  717         }
  718         fdp = td->td_proc->p_fd;
  719         switch (com) {
  720         case FIONCLEX:
  721                 FILEDESC_XLOCK(fdp);
  722                 fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE;
  723                 FILEDESC_XUNLOCK(fdp);
  724                 goto out;
  725         case FIOCLEX:
  726                 FILEDESC_XLOCK(fdp);
  727                 fdp->fd_ofileflags[fd] |= UF_EXCLOSE;
  728                 FILEDESC_XUNLOCK(fdp);
  729                 goto out;
  730         case FIONBIO:
  731                 if ((tmp = *(int *)data))
  732                         atomic_set_int(&fp->f_flag, FNONBLOCK);
  733                 else
  734                         atomic_clear_int(&fp->f_flag, FNONBLOCK);
  735                 data = (void *)&tmp;
  736                 break;
  737         case FIOASYNC:
  738                 if ((tmp = *(int *)data))
  739                         atomic_set_int(&fp->f_flag, FASYNC);
  740                 else
  741                         atomic_clear_int(&fp->f_flag, FASYNC);
  742                 data = (void *)&tmp;
  743                 break;
  744         }
  745 
  746         error = fo_ioctl(fp, com, data, td->td_ucred, td);
  747 out:
  748         fdrop(fp, td);
  749         return (error);
  750 }
  751 
  752 int
  753 poll_no_poll(int events)
  754 {
  755         /*
  756          * Return true for read/write.  If the user asked for something
  757          * special, return POLLNVAL, so that clients have a way of
  758          * determining reliably whether or not the extended
  759          * functionality is present without hard-coding knowledge
  760          * of specific filesystem implementations.
  761          */
  762         if (events & ~POLLSTANDARD)
  763                 return (POLLNVAL);
  764 
  765         return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
  766 }
  767 
  768 int
  769 sys_pselect(struct thread *td, struct pselect_args *uap)
  770 {
  771         struct timespec ts;
  772         struct timeval tv, *tvp;
  773         sigset_t set, *uset;
  774         int error;
  775 
  776         if (uap->ts != NULL) {
  777                 error = copyin(uap->ts, &ts, sizeof(ts));
  778                 if (error != 0)
  779                     return (error);
  780                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
  781                 tvp = &tv;
  782         } else
  783                 tvp = NULL;
  784         if (uap->sm != NULL) {
  785                 error = copyin(uap->sm, &set, sizeof(set));
  786                 if (error != 0)
  787                         return (error);
  788                 uset = &set;
  789         } else
  790                 uset = NULL;
  791         return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  792             uset, NFDBITS));
  793 }
  794 
  795 int
  796 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
  797     struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
  798 {
  799         int error;
  800 
  801         if (uset != NULL) {
  802                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
  803                     &td->td_oldsigmask, 0);
  804                 if (error != 0)
  805                         return (error);
  806                 td->td_pflags |= TDP_OLDMASK;
  807                 /*
  808                  * Make sure that ast() is called on return to
  809                  * usermode and TDP_OLDMASK is cleared, restoring old
  810                  * sigmask.
  811                  */
  812                 thread_lock(td);
  813                 td->td_flags |= TDF_ASTPENDING;
  814                 thread_unlock(td);
  815         }
  816         error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
  817         return (error);
  818 }
  819 
  820 #ifndef _SYS_SYSPROTO_H_
  821 struct select_args {
  822         int     nd;
  823         fd_set  *in, *ou, *ex;
  824         struct  timeval *tv;
  825 };
  826 #endif
  827 int
  828 sys_select(struct thread *td, struct select_args *uap)
  829 {
  830         struct timeval tv, *tvp;
  831         int error;
  832 
  833         if (uap->tv != NULL) {
  834                 error = copyin(uap->tv, &tv, sizeof(tv));
  835                 if (error)
  836                         return (error);
  837                 tvp = &tv;
  838         } else
  839                 tvp = NULL;
  840 
  841         return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  842             NFDBITS));
  843 }
  844 
  845 /*
  846  * In the unlikely case when user specified n greater then the last
  847  * open file descriptor, check that no bits are set after the last
  848  * valid fd.  We must return EBADF if any is set.
  849  *
  850  * There are applications that rely on the behaviour.
  851  *
  852  * nd is fd_lastfile + 1.
  853  */
  854 static int
  855 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits)
  856 {
  857         char *addr, *oaddr;
  858         int b, i, res;
  859         uint8_t bits;
  860 
  861         if (nd >= ndu || fd_in == NULL)
  862                 return (0);
  863 
  864         oaddr = NULL;
  865         bits = 0; /* silence gcc */
  866         for (i = nd; i < ndu; i++) {
  867                 b = i / NBBY;
  868 #if BYTE_ORDER == LITTLE_ENDIAN
  869                 addr = (char *)fd_in + b;
  870 #else
  871                 addr = (char *)fd_in;
  872                 if (abi_nfdbits == NFDBITS) {
  873                         addr += rounddown(b, sizeof(fd_mask)) +
  874                             sizeof(fd_mask) - 1 - b % sizeof(fd_mask);
  875                 } else {
  876                         addr += rounddown(b, sizeof(uint32_t)) +
  877                             sizeof(uint32_t) - 1 - b % sizeof(uint32_t);
  878                 }
  879 #endif
  880                 if (addr != oaddr) {
  881                         res = fubyte(addr);
  882                         if (res == -1)
  883                                 return (EFAULT);
  884                         oaddr = addr;
  885                         bits = res;
  886                 }
  887                 if ((bits & (1 << (i % NBBY))) != 0)
  888                         return (EBADF);
  889         }
  890         return (0);
  891 }
  892 
  893 int
  894 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
  895     fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
  896 {
  897         struct filedesc *fdp;
  898         /*
  899          * The magic 2048 here is chosen to be just enough for FD_SETSIZE
  900          * infds with the new FD_SETSIZE of 1024, and more than enough for
  901          * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
  902          * of 256.
  903          */
  904         fd_mask s_selbits[howmany(2048, NFDBITS)];
  905         fd_mask *ibits[3], *obits[3], *selbits, *sbp;
  906         struct timeval atv, rtv, ttv;
  907         int error, lf, ndu, timo;
  908         u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
  909 
  910         if (nd < 0)
  911                 return (EINVAL);
  912         fdp = td->td_proc->p_fd;
  913         ndu = nd;
  914         lf = fdp->fd_lastfile;
  915         if (nd > lf + 1)
  916                 nd = lf + 1;
  917 
  918         error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits);
  919         if (error != 0)
  920                 return (error);
  921         error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits);
  922         if (error != 0)
  923                 return (error);
  924         error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits);
  925         if (error != 0)
  926                 return (error);
  927 
  928         /*
  929          * Allocate just enough bits for the non-null fd_sets.  Use the
  930          * preallocated auto buffer if possible.
  931          */
  932         nfdbits = roundup(nd, NFDBITS);
  933         ncpbytes = nfdbits / NBBY;
  934         ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
  935         nbufbytes = 0;
  936         if (fd_in != NULL)
  937                 nbufbytes += 2 * ncpbytes;
  938         if (fd_ou != NULL)
  939                 nbufbytes += 2 * ncpbytes;
  940         if (fd_ex != NULL)
  941                 nbufbytes += 2 * ncpbytes;
  942         if (nbufbytes <= sizeof s_selbits)
  943                 selbits = &s_selbits[0];
  944         else
  945                 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
  946 
  947         /*
  948          * Assign pointers into the bit buffers and fetch the input bits.
  949          * Put the output buffers together so that they can be bzeroed
  950          * together.
  951          */
  952         sbp = selbits;
  953 #define getbits(name, x) \
  954         do {                                                            \
  955                 if (name == NULL) {                                     \
  956                         ibits[x] = NULL;                                \
  957                         obits[x] = NULL;                                \
  958                 } else {                                                \
  959                         ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp;   \
  960                         obits[x] = sbp;                                 \
  961                         sbp += ncpbytes / sizeof *sbp;                  \
  962                         error = copyin(name, ibits[x], ncpubytes);      \
  963                         if (error != 0)                                 \
  964                                 goto done;                              \
  965                         bzero((char *)ibits[x] + ncpubytes,             \
  966                             ncpbytes - ncpubytes);                      \
  967                 }                                                       \
  968         } while (0)
  969         getbits(fd_in, 0);
  970         getbits(fd_ou, 1);
  971         getbits(fd_ex, 2);
  972 #undef  getbits
  973 
  974 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
  975         /*
  976          * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
  977          * we are running under 32-bit emulation. This should be more
  978          * generic.
  979          */
  980 #define swizzle_fdset(bits)                                             \
  981         if (abi_nfdbits != NFDBITS && bits != NULL) {                   \
  982                 int i;                                                  \
  983                 for (i = 0; i < ncpbytes / sizeof *sbp; i++)            \
  984                         bits[i] = (bits[i] >> 32) | (bits[i] << 32);    \
  985         }
  986 #else
  987 #define swizzle_fdset(bits)
  988 #endif
  989 
  990         /* Make sure the bit order makes it through an ABI transition */
  991         swizzle_fdset(ibits[0]);
  992         swizzle_fdset(ibits[1]);
  993         swizzle_fdset(ibits[2]);
  994         
  995         if (nbufbytes != 0)
  996                 bzero(selbits, nbufbytes / 2);
  997 
  998         if (tvp != NULL) {
  999                 atv = *tvp;
 1000                 if (itimerfix(&atv)) {
 1001                         error = EINVAL;
 1002                         goto done;
 1003                 }
 1004                 getmicrouptime(&rtv);
 1005                 timevaladd(&atv, &rtv);
 1006         } else {
 1007                 atv.tv_sec = 0;
 1008                 atv.tv_usec = 0;
 1009         }
 1010         timo = 0;
 1011         seltdinit(td);
 1012         /* Iterate until the timeout expires or descriptors become ready. */
 1013         for (;;) {
 1014                 error = selscan(td, ibits, obits, nd);
 1015                 if (error || td->td_retval[0] != 0)
 1016                         break;
 1017                 if (atv.tv_sec || atv.tv_usec) {
 1018                         getmicrouptime(&rtv);
 1019                         if (timevalcmp(&rtv, &atv, >=))
 1020                                 break;
 1021                         ttv = atv;
 1022                         timevalsub(&ttv, &rtv);
 1023                         timo = ttv.tv_sec > 24 * 60 * 60 ?
 1024                             24 * 60 * 60 * hz : tvtohz(&ttv);
 1025                 }
 1026                 error = seltdwait(td, timo);
 1027                 if (error)
 1028                         break;
 1029                 error = selrescan(td, ibits, obits);
 1030                 if (error || td->td_retval[0] != 0)
 1031                         break;
 1032         }
 1033         seltdclear(td);
 1034 
 1035 done:
 1036         /* select is not restarted after signals... */
 1037         if (error == ERESTART)
 1038                 error = EINTR;
 1039         if (error == EWOULDBLOCK)
 1040                 error = 0;
 1041 
 1042         /* swizzle bit order back, if necessary */
 1043         swizzle_fdset(obits[0]);
 1044         swizzle_fdset(obits[1]);
 1045         swizzle_fdset(obits[2]);
 1046 #undef swizzle_fdset
 1047 
 1048 #define putbits(name, x) \
 1049         if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
 1050                 error = error2;
 1051         if (error == 0) {
 1052                 int error2;
 1053 
 1054                 putbits(fd_in, 0);
 1055                 putbits(fd_ou, 1);
 1056                 putbits(fd_ex, 2);
 1057 #undef putbits
 1058         }
 1059         if (selbits != &s_selbits[0])
 1060                 free(selbits, M_SELECT);
 1061 
 1062         return (error);
 1063 }
 1064 /* 
 1065  * Convert a select bit set to poll flags.
 1066  *
 1067  * The backend always returns POLLHUP/POLLERR if appropriate and we
 1068  * return this as a set bit in any set.
 1069  */
 1070 static int select_flags[3] = {
 1071     POLLRDNORM | POLLHUP | POLLERR,
 1072     POLLWRNORM | POLLHUP | POLLERR,
 1073     POLLRDBAND | POLLERR
 1074 };
 1075 
 1076 /*
 1077  * Compute the fo_poll flags required for a fd given by the index and
 1078  * bit position in the fd_mask array.
 1079  */
 1080 static __inline int
 1081 selflags(fd_mask **ibits, int idx, fd_mask bit)
 1082 {
 1083         int flags;
 1084         int msk;
 1085 
 1086         flags = 0;
 1087         for (msk = 0; msk < 3; msk++) {
 1088                 if (ibits[msk] == NULL)
 1089                         continue;
 1090                 if ((ibits[msk][idx] & bit) == 0)
 1091                         continue;
 1092                 flags |= select_flags[msk];
 1093         }
 1094         return (flags);
 1095 }
 1096 
 1097 /*
 1098  * Set the appropriate output bits given a mask of fired events and the
 1099  * input bits originally requested.
 1100  */
 1101 static __inline int
 1102 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
 1103 {
 1104         int msk;
 1105         int n;
 1106 
 1107         n = 0;
 1108         for (msk = 0; msk < 3; msk++) {
 1109                 if ((events & select_flags[msk]) == 0)
 1110                         continue;
 1111                 if (ibits[msk] == NULL)
 1112                         continue;
 1113                 if ((ibits[msk][idx] & bit) == 0)
 1114                         continue;
 1115                 /*
 1116                  * XXX Check for a duplicate set.  This can occur because a
 1117                  * socket calls selrecord() twice for each poll() call
 1118                  * resulting in two selfds per real fd.  selrescan() will
 1119                  * call selsetbits twice as a result.
 1120                  */
 1121                 if ((obits[msk][idx] & bit) != 0)
 1122                         continue;
 1123                 obits[msk][idx] |= bit;
 1124                 n++;
 1125         }
 1126 
 1127         return (n);
 1128 }
 1129 
 1130 static __inline int
 1131 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp)
 1132 {
 1133         struct file *fp;
 1134 #ifdef CAPABILITIES
 1135         struct file *fp_fromcap;
 1136         int error;
 1137 #endif
 1138 
 1139         if ((fp = fget_unlocked(fdp, fd)) == NULL)
 1140                 return (EBADF);
 1141 #ifdef CAPABILITIES
 1142         /*
 1143          * If the file descriptor is for a capability, test rights and use
 1144          * the file descriptor references by the capability.
 1145          */
 1146         error = cap_funwrap(fp, CAP_POLL_EVENT, &fp_fromcap);
 1147         if (error) {
 1148                 fdrop(fp, curthread);
 1149                 return (error);
 1150         }
 1151         if (fp != fp_fromcap) {
 1152                 fhold(fp_fromcap);
 1153                 fdrop(fp, curthread);
 1154                 fp = fp_fromcap;
 1155         }
 1156 #endif /* CAPABILITIES */
 1157         *fpp = fp;
 1158         return (0);
 1159 }
 1160 
 1161 /*
 1162  * Traverse the list of fds attached to this thread's seltd and check for
 1163  * completion.
 1164  */
 1165 static int
 1166 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
 1167 {
 1168         struct filedesc *fdp;
 1169         struct selinfo *si;
 1170         struct seltd *stp;
 1171         struct selfd *sfp;
 1172         struct selfd *sfn;
 1173         struct file *fp;
 1174         fd_mask bit;
 1175         int fd, ev, n, idx;
 1176         int error;
 1177 
 1178         fdp = td->td_proc->p_fd;
 1179         stp = td->td_sel;
 1180         n = 0;
 1181         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1182                 fd = (int)(uintptr_t)sfp->sf_cookie;
 1183                 si = sfp->sf_si;
 1184                 selfdfree(stp, sfp);
 1185                 /* If the selinfo wasn't cleared the event didn't fire. */
 1186                 if (si != NULL)
 1187                         continue;
 1188                 error = getselfd_cap(fdp, fd, &fp);
 1189                 if (error)
 1190                         return (error);
 1191                 idx = fd / NFDBITS;
 1192                 bit = (fd_mask)1 << (fd % NFDBITS);
 1193                 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
 1194                 fdrop(fp, td);
 1195                 if (ev != 0)
 1196                         n += selsetbits(ibits, obits, idx, bit, ev);
 1197         }
 1198         stp->st_flags = 0;
 1199         td->td_retval[0] = n;
 1200         return (0);
 1201 }
 1202 
 1203 /*
 1204  * Perform the initial filedescriptor scan and register ourselves with
 1205  * each selinfo.
 1206  */
 1207 static int
 1208 selscan(td, ibits, obits, nfd)
 1209         struct thread *td;
 1210         fd_mask **ibits, **obits;
 1211         int nfd;
 1212 {
 1213         struct filedesc *fdp;
 1214         struct file *fp;
 1215         fd_mask bit;
 1216         int ev, flags, end, fd;
 1217         int n, idx;
 1218         int error;
 1219 
 1220         fdp = td->td_proc->p_fd;
 1221         n = 0;
 1222         for (idx = 0, fd = 0; fd < nfd; idx++) {
 1223                 end = imin(fd + NFDBITS, nfd);
 1224                 for (bit = 1; fd < end; bit <<= 1, fd++) {
 1225                         /* Compute the list of events we're interested in. */
 1226                         flags = selflags(ibits, idx, bit);
 1227                         if (flags == 0)
 1228                                 continue;
 1229                         error = getselfd_cap(fdp, fd, &fp);
 1230                         if (error)
 1231                                 return (error);
 1232                         selfdalloc(td, (void *)(uintptr_t)fd);
 1233                         ev = fo_poll(fp, flags, td->td_ucred, td);
 1234                         fdrop(fp, td);
 1235                         if (ev != 0)
 1236                                 n += selsetbits(ibits, obits, idx, bit, ev);
 1237                 }
 1238         }
 1239 
 1240         td->td_retval[0] = n;
 1241         return (0);
 1242 }
 1243 
 1244 #ifndef _SYS_SYSPROTO_H_
 1245 struct poll_args {
 1246         struct pollfd *fds;
 1247         u_int   nfds;
 1248         int     timeout;
 1249 };
 1250 #endif
 1251 int
 1252 sys_poll(td, uap)
 1253         struct thread *td;
 1254         struct poll_args *uap;
 1255 {
 1256         struct pollfd *bits;
 1257         struct pollfd smallbits[32];
 1258         struct timeval atv, rtv, ttv;
 1259         int error, timo;
 1260         u_int nfds;
 1261         size_t ni;
 1262 
 1263         nfds = uap->nfds;
 1264         if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 
 1265                 return (EINVAL);
 1266         ni = nfds * sizeof(struct pollfd);
 1267         if (ni > sizeof(smallbits))
 1268                 bits = malloc(ni, M_TEMP, M_WAITOK);
 1269         else
 1270                 bits = smallbits;
 1271         error = copyin(uap->fds, bits, ni);
 1272         if (error)
 1273                 goto done;
 1274         if (uap->timeout != INFTIM) {
 1275                 atv.tv_sec = uap->timeout / 1000;
 1276                 atv.tv_usec = (uap->timeout % 1000) * 1000;
 1277                 if (itimerfix(&atv)) {
 1278                         error = EINVAL;
 1279                         goto done;
 1280                 }
 1281                 getmicrouptime(&rtv);
 1282                 timevaladd(&atv, &rtv);
 1283         } else {
 1284                 atv.tv_sec = 0;
 1285                 atv.tv_usec = 0;
 1286         }
 1287         timo = 0;
 1288         seltdinit(td);
 1289         /* Iterate until the timeout expires or descriptors become ready. */
 1290         for (;;) {
 1291                 error = pollscan(td, bits, nfds);
 1292                 if (error || td->td_retval[0] != 0)
 1293                         break;
 1294                 if (atv.tv_sec || atv.tv_usec) {
 1295                         getmicrouptime(&rtv);
 1296                         if (timevalcmp(&rtv, &atv, >=))
 1297                                 break;
 1298                         ttv = atv;
 1299                         timevalsub(&ttv, &rtv);
 1300                         timo = ttv.tv_sec > 24 * 60 * 60 ?
 1301                             24 * 60 * 60 * hz : tvtohz(&ttv);
 1302                 }
 1303                 error = seltdwait(td, timo);
 1304                 if (error)
 1305                         break;
 1306                 error = pollrescan(td);
 1307                 if (error || td->td_retval[0] != 0)
 1308                         break;
 1309         }
 1310         seltdclear(td);
 1311 
 1312 done:
 1313         /* poll is not restarted after signals... */
 1314         if (error == ERESTART)
 1315                 error = EINTR;
 1316         if (error == EWOULDBLOCK)
 1317                 error = 0;
 1318         if (error == 0) {
 1319                 error = pollout(td, bits, uap->fds, nfds);
 1320                 if (error)
 1321                         goto out;
 1322         }
 1323 out:
 1324         if (ni > sizeof(smallbits))
 1325                 free(bits, M_TEMP);
 1326         return (error);
 1327 }
 1328 
 1329 static int
 1330 pollrescan(struct thread *td)
 1331 {
 1332         struct seltd *stp;
 1333         struct selfd *sfp;
 1334         struct selfd *sfn;
 1335         struct selinfo *si;
 1336         struct filedesc *fdp;
 1337         struct file *fp;
 1338         struct pollfd *fd;
 1339         int n;
 1340 
 1341         n = 0;
 1342         fdp = td->td_proc->p_fd;
 1343         stp = td->td_sel;
 1344         FILEDESC_SLOCK(fdp);
 1345         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1346                 fd = (struct pollfd *)sfp->sf_cookie;
 1347                 si = sfp->sf_si;
 1348                 selfdfree(stp, sfp);
 1349                 /* If the selinfo wasn't cleared the event didn't fire. */
 1350                 if (si != NULL)
 1351                         continue;
 1352                 fp = fdp->fd_ofiles[fd->fd];
 1353 #ifdef CAPABILITIES
 1354                 if ((fp == NULL)
 1355                     || (cap_funwrap(fp, CAP_POLL_EVENT, &fp) != 0)) {
 1356 #else
 1357                 if (fp == NULL) {
 1358 #endif
 1359                         fd->revents = POLLNVAL;
 1360                         n++;
 1361                         continue;
 1362                 }
 1363 
 1364                 /*
 1365                  * Note: backend also returns POLLHUP and
 1366                  * POLLERR if appropriate.
 1367                  */
 1368                 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
 1369                 if (fd->revents != 0)
 1370                         n++;
 1371         }
 1372         FILEDESC_SUNLOCK(fdp);
 1373         stp->st_flags = 0;
 1374         td->td_retval[0] = n;
 1375         return (0);
 1376 }
 1377 
 1378 
 1379 static int
 1380 pollout(td, fds, ufds, nfd)
 1381         struct thread *td;
 1382         struct pollfd *fds;
 1383         struct pollfd *ufds;
 1384         u_int nfd;
 1385 {
 1386         int error = 0;
 1387         u_int i = 0;
 1388         u_int n = 0;
 1389 
 1390         for (i = 0; i < nfd; i++) {
 1391                 error = copyout(&fds->revents, &ufds->revents,
 1392                     sizeof(ufds->revents));
 1393                 if (error)
 1394                         return (error);
 1395                 if (fds->revents != 0)
 1396                         n++;
 1397                 fds++;
 1398                 ufds++;
 1399         }
 1400         td->td_retval[0] = n;
 1401         return (0);
 1402 }
 1403 
 1404 static int
 1405 pollscan(td, fds, nfd)
 1406         struct thread *td;
 1407         struct pollfd *fds;
 1408         u_int nfd;
 1409 {
 1410         struct filedesc *fdp = td->td_proc->p_fd;
 1411         int i;
 1412         struct file *fp;
 1413         int n = 0;
 1414 
 1415         FILEDESC_SLOCK(fdp);
 1416         for (i = 0; i < nfd; i++, fds++) {
 1417                 if (fds->fd >= fdp->fd_nfiles) {
 1418                         fds->revents = POLLNVAL;
 1419                         n++;
 1420                 } else if (fds->fd < 0) {
 1421                         fds->revents = 0;
 1422                 } else {
 1423                         fp = fdp->fd_ofiles[fds->fd];
 1424 #ifdef CAPABILITIES
 1425                         if ((fp == NULL)
 1426                             || (cap_funwrap(fp, CAP_POLL_EVENT, &fp) != 0)) {
 1427 #else
 1428                         if (fp == NULL) {
 1429 #endif
 1430                                 fds->revents = POLLNVAL;
 1431                                 n++;
 1432                         } else {
 1433                                 /*
 1434                                  * Note: backend also returns POLLHUP and
 1435                                  * POLLERR if appropriate.
 1436                                  */
 1437                                 selfdalloc(td, fds);
 1438                                 fds->revents = fo_poll(fp, fds->events,
 1439                                     td->td_ucred, td);
 1440                                 /*
 1441                                  * POSIX requires POLLOUT to be never
 1442                                  * set simultaneously with POLLHUP.
 1443                                  */
 1444                                 if ((fds->revents & POLLHUP) != 0)
 1445                                         fds->revents &= ~POLLOUT;
 1446 
 1447                                 if (fds->revents != 0)
 1448                                         n++;
 1449                         }
 1450                 }
 1451         }
 1452         FILEDESC_SUNLOCK(fdp);
 1453         td->td_retval[0] = n;
 1454         return (0);
 1455 }
 1456 
 1457 /*
 1458  * OpenBSD poll system call.
 1459  *
 1460  * XXX this isn't quite a true representation..  OpenBSD uses select ops.
 1461  */
 1462 #ifndef _SYS_SYSPROTO_H_
 1463 struct openbsd_poll_args {
 1464         struct pollfd *fds;
 1465         u_int   nfds;
 1466         int     timeout;
 1467 };
 1468 #endif
 1469 int
 1470 sys_openbsd_poll(td, uap)
 1471         register struct thread *td;
 1472         register struct openbsd_poll_args *uap;
 1473 {
 1474         return (sys_poll(td, (struct poll_args *)uap));
 1475 }
 1476 
 1477 /*
 1478  * XXX This was created specifically to support netncp and netsmb.  This
 1479  * allows the caller to specify a socket to wait for events on.  It returns
 1480  * 0 if any events matched and an error otherwise.  There is no way to
 1481  * determine which events fired.
 1482  */
 1483 int
 1484 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
 1485 {
 1486         struct timeval atv, rtv, ttv;
 1487         int error, timo;
 1488 
 1489         if (tvp != NULL) {
 1490                 atv = *tvp;
 1491                 if (itimerfix(&atv))
 1492                         return (EINVAL);
 1493                 getmicrouptime(&rtv);
 1494                 timevaladd(&atv, &rtv);
 1495         } else {
 1496                 atv.tv_sec = 0;
 1497                 atv.tv_usec = 0;
 1498         }
 1499 
 1500         timo = 0;
 1501         seltdinit(td);
 1502         /*
 1503          * Iterate until the timeout expires or the socket becomes ready.
 1504          */
 1505         for (;;) {
 1506                 selfdalloc(td, NULL);
 1507                 error = sopoll(so, events, NULL, td);
 1508                 /* error here is actually the ready events. */
 1509                 if (error)
 1510                         return (0);
 1511                 if (atv.tv_sec || atv.tv_usec) {
 1512                         getmicrouptime(&rtv);
 1513                         if (timevalcmp(&rtv, &atv, >=)) {
 1514                                 seltdclear(td);
 1515                                 return (EWOULDBLOCK);
 1516                         }
 1517                         ttv = atv;
 1518                         timevalsub(&ttv, &rtv);
 1519                         timo = ttv.tv_sec > 24 * 60 * 60 ?
 1520                             24 * 60 * 60 * hz : tvtohz(&ttv);
 1521                 }
 1522                 error = seltdwait(td, timo);
 1523                 seltdclear(td);
 1524                 if (error)
 1525                         break;
 1526         }
 1527         /* XXX Duplicates ncp/smb behavior. */
 1528         if (error == ERESTART)
 1529                 error = 0;
 1530         return (error);
 1531 }
 1532 
 1533 /*
 1534  * Preallocate two selfds associated with 'cookie'.  Some fo_poll routines
 1535  * have two select sets, one for read and another for write.
 1536  */
 1537 static void
 1538 selfdalloc(struct thread *td, void *cookie)
 1539 {
 1540         struct seltd *stp;
 1541 
 1542         stp = td->td_sel;
 1543         if (stp->st_free1 == NULL)
 1544                 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1545         stp->st_free1->sf_td = stp;
 1546         stp->st_free1->sf_cookie = cookie;
 1547         if (stp->st_free2 == NULL)
 1548                 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1549         stp->st_free2->sf_td = stp;
 1550         stp->st_free2->sf_cookie = cookie;
 1551 }
 1552 
 1553 static void
 1554 selfdfree(struct seltd *stp, struct selfd *sfp)
 1555 {
 1556         STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
 1557         mtx_lock(sfp->sf_mtx);
 1558         if (sfp->sf_si)
 1559                 TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
 1560         mtx_unlock(sfp->sf_mtx);
 1561         uma_zfree(selfd_zone, sfp);
 1562 }
 1563 
 1564 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */
 1565 void
 1566 seldrain(sip)
 1567         struct selinfo *sip;
 1568 {
 1569 
 1570         /*
 1571          * This feature is already provided by doselwakeup(), thus it is
 1572          * enough to go for it.
 1573          * Eventually, the context, should take care to avoid races
 1574          * between thread calling select()/poll() and file descriptor
 1575          * detaching, but, again, the races are just the same as
 1576          * selwakeup().
 1577          */
 1578         doselwakeup(sip, -1);
 1579 }
 1580 
 1581 /*
 1582  * Record a select request.
 1583  */
 1584 void
 1585 selrecord(selector, sip)
 1586         struct thread *selector;
 1587         struct selinfo *sip;
 1588 {
 1589         struct selfd *sfp;
 1590         struct seltd *stp;
 1591         struct mtx *mtxp;
 1592 
 1593         stp = selector->td_sel;
 1594         /*
 1595          * Don't record when doing a rescan.
 1596          */
 1597         if (stp->st_flags & SELTD_RESCAN)
 1598                 return;
 1599         /*
 1600          * Grab one of the preallocated descriptors.
 1601          */
 1602         sfp = NULL;
 1603         if ((sfp = stp->st_free1) != NULL)
 1604                 stp->st_free1 = NULL;
 1605         else if ((sfp = stp->st_free2) != NULL)
 1606                 stp->st_free2 = NULL;
 1607         else
 1608                 panic("selrecord: No free selfd on selq");
 1609         mtxp = sip->si_mtx;
 1610         if (mtxp == NULL)
 1611                 mtxp = mtx_pool_find(mtxpool_select, sip);
 1612         /*
 1613          * Initialize the sfp and queue it in the thread.
 1614          */
 1615         sfp->sf_si = sip;
 1616         sfp->sf_mtx = mtxp;
 1617         STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
 1618         /*
 1619          * Now that we've locked the sip, check for initialization.
 1620          */
 1621         mtx_lock(mtxp);
 1622         if (sip->si_mtx == NULL) {
 1623                 sip->si_mtx = mtxp;
 1624                 TAILQ_INIT(&sip->si_tdlist);
 1625         }
 1626         /*
 1627          * Add this thread to the list of selfds listening on this selinfo.
 1628          */
 1629         TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
 1630         mtx_unlock(sip->si_mtx);
 1631 }
 1632 
 1633 /* Wake up a selecting thread. */
 1634 void
 1635 selwakeup(sip)
 1636         struct selinfo *sip;
 1637 {
 1638         doselwakeup(sip, -1);
 1639 }
 1640 
 1641 /* Wake up a selecting thread, and set its priority. */
 1642 void
 1643 selwakeuppri(sip, pri)
 1644         struct selinfo *sip;
 1645         int pri;
 1646 {
 1647         doselwakeup(sip, pri);
 1648 }
 1649 
 1650 /*
 1651  * Do a wakeup when a selectable event occurs.
 1652  */
 1653 static void
 1654 doselwakeup(sip, pri)
 1655         struct selinfo *sip;
 1656         int pri;
 1657 {
 1658         struct selfd *sfp;
 1659         struct selfd *sfn;
 1660         struct seltd *stp;
 1661 
 1662         /* If it's not initialized there can't be any waiters. */
 1663         if (sip->si_mtx == NULL)
 1664                 return;
 1665         /*
 1666          * Locking the selinfo locks all selfds associated with it.
 1667          */
 1668         mtx_lock(sip->si_mtx);
 1669         TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
 1670                 /*
 1671                  * Once we remove this sfp from the list and clear the
 1672                  * sf_si seltdclear will know to ignore this si.
 1673                  */
 1674                 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
 1675                 sfp->sf_si = NULL;
 1676                 stp = sfp->sf_td;
 1677                 mtx_lock(&stp->st_mtx);
 1678                 stp->st_flags |= SELTD_PENDING;
 1679                 cv_broadcastpri(&stp->st_wait, pri);
 1680                 mtx_unlock(&stp->st_mtx);
 1681         }
 1682         mtx_unlock(sip->si_mtx);
 1683 }
 1684 
 1685 static void
 1686 seltdinit(struct thread *td)
 1687 {
 1688         struct seltd *stp;
 1689 
 1690         if ((stp = td->td_sel) != NULL)
 1691                 goto out;
 1692         td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
 1693         mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
 1694         cv_init(&stp->st_wait, "select");
 1695 out:
 1696         stp->st_flags = 0;
 1697         STAILQ_INIT(&stp->st_selq);
 1698 }
 1699 
 1700 static int
 1701 seltdwait(struct thread *td, int timo)
 1702 {
 1703         struct seltd *stp;
 1704         int error;
 1705 
 1706         stp = td->td_sel;
 1707         /*
 1708          * An event of interest may occur while we do not hold the seltd
 1709          * locked so check the pending flag before we sleep.
 1710          */
 1711         mtx_lock(&stp->st_mtx);
 1712         /*
 1713          * Any further calls to selrecord will be a rescan.
 1714          */
 1715         stp->st_flags |= SELTD_RESCAN;
 1716         if (stp->st_flags & SELTD_PENDING) {
 1717                 mtx_unlock(&stp->st_mtx);
 1718                 return (0);
 1719         }
 1720         if (timo > 0)
 1721                 error = cv_timedwait_sig(&stp->st_wait, &stp->st_mtx, timo);
 1722         else
 1723                 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
 1724         mtx_unlock(&stp->st_mtx);
 1725 
 1726         return (error);
 1727 }
 1728 
 1729 void
 1730 seltdfini(struct thread *td)
 1731 {
 1732         struct seltd *stp;
 1733 
 1734         stp = td->td_sel;
 1735         if (stp == NULL)
 1736                 return;
 1737         if (stp->st_free1)
 1738                 uma_zfree(selfd_zone, stp->st_free1);
 1739         if (stp->st_free2)
 1740                 uma_zfree(selfd_zone, stp->st_free2);
 1741         td->td_sel = NULL;
 1742         free(stp, M_SELECT);
 1743 }
 1744 
 1745 /*
 1746  * Remove the references to the thread from all of the objects we were
 1747  * polling.
 1748  */
 1749 static void
 1750 seltdclear(struct thread *td)
 1751 {
 1752         struct seltd *stp;
 1753         struct selfd *sfp;
 1754         struct selfd *sfn;
 1755 
 1756         stp = td->td_sel;
 1757         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
 1758                 selfdfree(stp, sfp);
 1759         stp->st_flags = 0;
 1760 }
 1761 
 1762 static void selectinit(void *);
 1763 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
 1764 static void
 1765 selectinit(void *dummy __unused)
 1766 {
 1767 
 1768         selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
 1769             NULL, NULL, UMA_ALIGN_PTR, 0);
 1770         mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
 1771 }

Cache object: 2876434d693974659b4a0be77367a077


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