The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/kern/sys_generic.c

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 1982, 1986, 1989, 1993
    5  *      The Regents of the University of California.  All rights reserved.
    6  * (c) UNIX System Laboratories, Inc.
    7  * All or some portions of this file are derived from material licensed
    8  * to the University of California by American Telephone and Telegraph
    9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   10  * the permission of UNIX System Laboratories, Inc.
   11  *
   12  * Redistribution and use in source and binary forms, with or without
   13  * modification, are permitted provided that the following conditions
   14  * are met:
   15  * 1. Redistributions of source code must retain the above copyright
   16  *    notice, this list of conditions and the following disclaimer.
   17  * 2. Redistributions in binary form must reproduce the above copyright
   18  *    notice, this list of conditions and the following disclaimer in the
   19  *    documentation and/or other materials provided with the distribution.
   20  * 3. Neither the name of the University nor the names of its contributors
   21  *    may be used to endorse or promote products derived from this software
   22  *    without specific prior written permission.
   23  *
   24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   34  * SUCH DAMAGE.
   35  *
   36  *      @(#)sys_generic.c       8.5 (Berkeley) 1/21/94
   37  */
   38 
   39 #include <sys/cdefs.h>
   40 __FBSDID("$FreeBSD: stable/12/sys/kern/sys_generic.c 360330 2020-04-26 08:34:03Z hselasky $");
   41 
   42 #include "opt_capsicum.h"
   43 #include "opt_ktrace.h"
   44 
   45 #include <sys/param.h>
   46 #include <sys/systm.h>
   47 #include <sys/sysproto.h>
   48 #include <sys/capsicum.h>
   49 #include <sys/filedesc.h>
   50 #include <sys/filio.h>
   51 #include <sys/fcntl.h>
   52 #include <sys/file.h>
   53 #include <sys/lock.h>
   54 #include <sys/proc.h>
   55 #include <sys/signalvar.h>
   56 #include <sys/socketvar.h>
   57 #include <sys/uio.h>
   58 #include <sys/kernel.h>
   59 #include <sys/ktr.h>
   60 #include <sys/limits.h>
   61 #include <sys/malloc.h>
   62 #include <sys/poll.h>
   63 #include <sys/resourcevar.h>
   64 #include <sys/selinfo.h>
   65 #include <sys/sleepqueue.h>
   66 #include <sys/syscallsubr.h>
   67 #include <sys/sysctl.h>
   68 #include <sys/sysent.h>
   69 #include <sys/vnode.h>
   70 #include <sys/bio.h>
   71 #include <sys/buf.h>
   72 #include <sys/condvar.h>
   73 #ifdef KTRACE
   74 #include <sys/ktrace.h>
   75 #endif
   76 
   77 #include <security/audit/audit.h>
   78 
   79 /*
   80  * The following macro defines how many bytes will be allocated from
   81  * the stack instead of memory allocated when passing the IOCTL data
   82  * structures from userspace and to the kernel. Some IOCTLs having
   83  * small data structures are used very frequently and this small
   84  * buffer on the stack gives a significant speedup improvement for
   85  * those requests. The value of this define should be greater or equal
   86  * to 64 bytes and should also be power of two. The data structure is
   87  * currently hard-aligned to a 8-byte boundary on the stack. This
   88  * should currently be sufficient for all supported platforms.
   89  */
   90 #define SYS_IOCTL_SMALL_SIZE    128     /* bytes */
   91 #define SYS_IOCTL_SMALL_ALIGN   8       /* bytes */
   92 
   93 #ifdef __LP64__
   94 static int iosize_max_clamp = 0;
   95 SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW,
   96     &iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX");
   97 static int devfs_iosize_max_clamp = 1;
   98 SYSCTL_INT(_debug, OID_AUTO, devfs_iosize_max_clamp, CTLFLAG_RW,
   99     &devfs_iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX for devices");
  100 #endif
  101 
  102 /*
  103  * Assert that the return value of read(2) and write(2) syscalls fits
  104  * into a register.  If not, an architecture will need to provide the
  105  * usermode wrappers to reconstruct the result.
  106  */
  107 CTASSERT(sizeof(register_t) >= sizeof(size_t));
  108 
  109 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer");
  110 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer");
  111 MALLOC_DEFINE(M_IOV, "iov", "large iov's");
  112 
  113 static int      pollout(struct thread *, struct pollfd *, struct pollfd *,
  114                     u_int);
  115 static int      pollscan(struct thread *, struct pollfd *, u_int);
  116 static int      pollrescan(struct thread *);
  117 static int      selscan(struct thread *, fd_mask **, fd_mask **, int);
  118 static int      selrescan(struct thread *, fd_mask **, fd_mask **);
  119 static void     selfdalloc(struct thread *, void *);
  120 static void     selfdfree(struct seltd *, struct selfd *);
  121 static int      dofileread(struct thread *, int, struct file *, struct uio *,
  122                     off_t, int);
  123 static int      dofilewrite(struct thread *, int, struct file *, struct uio *,
  124                     off_t, int);
  125 static void     doselwakeup(struct selinfo *, int);
  126 static void     seltdinit(struct thread *);
  127 static int      seltdwait(struct thread *, sbintime_t, sbintime_t);
  128 static void     seltdclear(struct thread *);
  129 
  130 /*
  131  * One seltd per-thread allocated on demand as needed.
  132  *
  133  *      t - protected by st_mtx
  134  *      k - Only accessed by curthread or read-only
  135  */
  136 struct seltd {
  137         STAILQ_HEAD(, selfd)    st_selq;        /* (k) List of selfds. */
  138         struct selfd            *st_free1;      /* (k) free fd for read set. */
  139         struct selfd            *st_free2;      /* (k) free fd for write set. */
  140         struct mtx              st_mtx;         /* Protects struct seltd */
  141         struct cv               st_wait;        /* (t) Wait channel. */
  142         int                     st_flags;       /* (t) SELTD_ flags. */
  143 };
  144 
  145 #define SELTD_PENDING   0x0001                  /* We have pending events. */
  146 #define SELTD_RESCAN    0x0002                  /* Doing a rescan. */
  147 
  148 /*
  149  * One selfd allocated per-thread per-file-descriptor.
  150  *      f - protected by sf_mtx
  151  */
  152 struct selfd {
  153         STAILQ_ENTRY(selfd)     sf_link;        /* (k) fds owned by this td. */
  154         TAILQ_ENTRY(selfd)      sf_threads;     /* (f) fds on this selinfo. */
  155         struct selinfo          *sf_si;         /* (f) selinfo when linked. */
  156         struct mtx              *sf_mtx;        /* Pointer to selinfo mtx. */
  157         struct seltd            *sf_td;         /* (k) owning seltd. */
  158         void                    *sf_cookie;     /* (k) fd or pollfd. */
  159         u_int                   sf_refs;
  160 };
  161 
  162 static uma_zone_t selfd_zone;
  163 static struct mtx_pool *mtxpool_select;
  164 
  165 #ifdef __LP64__
  166 size_t
  167 devfs_iosize_max(void)
  168 {
  169 
  170         return (devfs_iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ?
  171             INT_MAX : SSIZE_MAX);
  172 }
  173 
  174 size_t
  175 iosize_max(void)
  176 {
  177 
  178         return (iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ?
  179             INT_MAX : SSIZE_MAX);
  180 }
  181 #endif
  182 
  183 #ifndef _SYS_SYSPROTO_H_
  184 struct read_args {
  185         int     fd;
  186         void    *buf;
  187         size_t  nbyte;
  188 };
  189 #endif
  190 int
  191 sys_read(struct thread *td, struct read_args *uap)
  192 {
  193         struct uio auio;
  194         struct iovec aiov;
  195         int error;
  196 
  197         if (uap->nbyte > IOSIZE_MAX)
  198                 return (EINVAL);
  199         aiov.iov_base = uap->buf;
  200         aiov.iov_len = uap->nbyte;
  201         auio.uio_iov = &aiov;
  202         auio.uio_iovcnt = 1;
  203         auio.uio_resid = uap->nbyte;
  204         auio.uio_segflg = UIO_USERSPACE;
  205         error = kern_readv(td, uap->fd, &auio);
  206         return (error);
  207 }
  208 
  209 /*
  210  * Positioned read system call
  211  */
  212 #ifndef _SYS_SYSPROTO_H_
  213 struct pread_args {
  214         int     fd;
  215         void    *buf;
  216         size_t  nbyte;
  217         int     pad;
  218         off_t   offset;
  219 };
  220 #endif
  221 int
  222 sys_pread(struct thread *td, struct pread_args *uap)
  223 {
  224 
  225         return (kern_pread(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
  226 }
  227 
  228 int
  229 kern_pread(struct thread *td, int fd, void *buf, size_t nbyte, off_t offset)
  230 {
  231         struct uio auio;
  232         struct iovec aiov;
  233         int error;
  234 
  235         if (nbyte > IOSIZE_MAX)
  236                 return (EINVAL);
  237         aiov.iov_base = buf;
  238         aiov.iov_len = nbyte;
  239         auio.uio_iov = &aiov;
  240         auio.uio_iovcnt = 1;
  241         auio.uio_resid = nbyte;
  242         auio.uio_segflg = UIO_USERSPACE;
  243         error = kern_preadv(td, fd, &auio, offset);
  244         return (error);
  245 }
  246 
  247 #if defined(COMPAT_FREEBSD6)
  248 int
  249 freebsd6_pread(struct thread *td, struct freebsd6_pread_args *uap)
  250 {
  251 
  252         return (kern_pread(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
  253 }
  254 #endif
  255 
  256 /*
  257  * Scatter read system call.
  258  */
  259 #ifndef _SYS_SYSPROTO_H_
  260 struct readv_args {
  261         int     fd;
  262         struct  iovec *iovp;
  263         u_int   iovcnt;
  264 };
  265 #endif
  266 int
  267 sys_readv(struct thread *td, struct readv_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_readv(td, uap->fd, auio);
  276         free(auio, M_IOV);
  277         return (error);
  278 }
  279 
  280 int
  281 kern_readv(struct thread *td, int fd, struct uio *auio)
  282 {
  283         struct file *fp;
  284         int error;
  285 
  286         error = fget_read(td, fd, &cap_read_rights, &fp);
  287         if (error)
  288                 return (error);
  289         error = dofileread(td, fd, fp, auio, (off_t)-1, 0);
  290         fdrop(fp, td);
  291         return (error);
  292 }
  293 
  294 /*
  295  * Scatter positioned read system call.
  296  */
  297 #ifndef _SYS_SYSPROTO_H_
  298 struct preadv_args {
  299         int     fd;
  300         struct  iovec *iovp;
  301         u_int   iovcnt;
  302         off_t   offset;
  303 };
  304 #endif
  305 int
  306 sys_preadv(struct thread *td, struct preadv_args *uap)
  307 {
  308         struct uio *auio;
  309         int error;
  310 
  311         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  312         if (error)
  313                 return (error);
  314         error = kern_preadv(td, uap->fd, auio, uap->offset);
  315         free(auio, M_IOV);
  316         return (error);
  317 }
  318 
  319 int
  320 kern_preadv(struct thread *td, int fd, struct uio *auio, off_t offset)
  321 {
  322         struct file *fp;
  323         int error;
  324 
  325         error = fget_read(td, fd, &cap_pread_rights, &fp);
  326         if (error)
  327                 return (error);
  328         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  329                 error = ESPIPE;
  330         else if (offset < 0 &&
  331             (fp->f_vnode == NULL || fp->f_vnode->v_type != VCHR))
  332                 error = EINVAL;
  333         else
  334                 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET);
  335         fdrop(fp, td);
  336         return (error);
  337 }
  338 
  339 /*
  340  * Common code for readv and preadv that reads data in
  341  * from a file using the passed in uio, offset, and flags.
  342  */
  343 static int
  344 dofileread(struct thread *td, int fd, struct file *fp, struct uio *auio,
  345     off_t offset, int flags)
  346 {
  347         ssize_t cnt;
  348         int error;
  349 #ifdef KTRACE
  350         struct uio *ktruio = NULL;
  351 #endif
  352 
  353         AUDIT_ARG_FD(fd);
  354 
  355         /* Finish zero length reads right here */
  356         if (auio->uio_resid == 0) {
  357                 td->td_retval[0] = 0;
  358                 return (0);
  359         }
  360         auio->uio_rw = UIO_READ;
  361         auio->uio_offset = offset;
  362         auio->uio_td = td;
  363 #ifdef KTRACE
  364         if (KTRPOINT(td, KTR_GENIO)) 
  365                 ktruio = cloneuio(auio);
  366 #endif
  367         cnt = auio->uio_resid;
  368         if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) {
  369                 if (auio->uio_resid != cnt && (error == ERESTART ||
  370                     error == EINTR || error == EWOULDBLOCK))
  371                         error = 0;
  372         }
  373         cnt -= auio->uio_resid;
  374 #ifdef KTRACE
  375         if (ktruio != NULL) {
  376                 ktruio->uio_resid = cnt;
  377                 ktrgenio(fd, UIO_READ, ktruio, error);
  378         }
  379 #endif
  380         td->td_retval[0] = cnt;
  381         return (error);
  382 }
  383 
  384 #ifndef _SYS_SYSPROTO_H_
  385 struct write_args {
  386         int     fd;
  387         const void *buf;
  388         size_t  nbyte;
  389 };
  390 #endif
  391 int
  392 sys_write(struct thread *td, struct write_args *uap)
  393 {
  394         struct uio auio;
  395         struct iovec aiov;
  396         int error;
  397 
  398         if (uap->nbyte > IOSIZE_MAX)
  399                 return (EINVAL);
  400         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  401         aiov.iov_len = uap->nbyte;
  402         auio.uio_iov = &aiov;
  403         auio.uio_iovcnt = 1;
  404         auio.uio_resid = uap->nbyte;
  405         auio.uio_segflg = UIO_USERSPACE;
  406         error = kern_writev(td, uap->fd, &auio);
  407         return (error);
  408 }
  409 
  410 /*
  411  * Positioned write system call.
  412  */
  413 #ifndef _SYS_SYSPROTO_H_
  414 struct pwrite_args {
  415         int     fd;
  416         const void *buf;
  417         size_t  nbyte;
  418         int     pad;
  419         off_t   offset;
  420 };
  421 #endif
  422 int
  423 sys_pwrite(struct thread *td, struct pwrite_args *uap)
  424 {
  425 
  426         return (kern_pwrite(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
  427 }
  428 
  429 int
  430 kern_pwrite(struct thread *td, int fd, const void *buf, size_t nbyte,
  431     off_t offset)
  432 {
  433         struct uio auio;
  434         struct iovec aiov;
  435         int error;
  436 
  437         if (nbyte > IOSIZE_MAX)
  438                 return (EINVAL);
  439         aiov.iov_base = (void *)(uintptr_t)buf;
  440         aiov.iov_len = nbyte;
  441         auio.uio_iov = &aiov;
  442         auio.uio_iovcnt = 1;
  443         auio.uio_resid = nbyte;
  444         auio.uio_segflg = UIO_USERSPACE;
  445         error = kern_pwritev(td, fd, &auio, offset);
  446         return (error);
  447 }
  448 
  449 #if defined(COMPAT_FREEBSD6)
  450 int
  451 freebsd6_pwrite(struct thread *td, struct freebsd6_pwrite_args *uap)
  452 {
  453 
  454         return (kern_pwrite(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
  455 }
  456 #endif
  457 
  458 /*
  459  * Gather write system call.
  460  */
  461 #ifndef _SYS_SYSPROTO_H_
  462 struct writev_args {
  463         int     fd;
  464         struct  iovec *iovp;
  465         u_int   iovcnt;
  466 };
  467 #endif
  468 int
  469 sys_writev(struct thread *td, struct writev_args *uap)
  470 {
  471         struct uio *auio;
  472         int error;
  473 
  474         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  475         if (error)
  476                 return (error);
  477         error = kern_writev(td, uap->fd, auio);
  478         free(auio, M_IOV);
  479         return (error);
  480 }
  481 
  482 int
  483 kern_writev(struct thread *td, int fd, struct uio *auio)
  484 {
  485         struct file *fp;
  486         int error;
  487 
  488         error = fget_write(td, fd, &cap_write_rights, &fp);
  489         if (error)
  490                 return (error);
  491         error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0);
  492         fdrop(fp, td);
  493         return (error);
  494 }
  495 
  496 /*
  497  * Gather positioned write system call.
  498  */
  499 #ifndef _SYS_SYSPROTO_H_
  500 struct pwritev_args {
  501         int     fd;
  502         struct  iovec *iovp;
  503         u_int   iovcnt;
  504         off_t   offset;
  505 };
  506 #endif
  507 int
  508 sys_pwritev(struct thread *td, struct pwritev_args *uap)
  509 {
  510         struct uio *auio;
  511         int error;
  512 
  513         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  514         if (error)
  515                 return (error);
  516         error = kern_pwritev(td, uap->fd, auio, uap->offset);
  517         free(auio, M_IOV);
  518         return (error);
  519 }
  520 
  521 int
  522 kern_pwritev(struct thread *td, int fd, struct uio *auio, off_t offset)
  523 {
  524         struct file *fp;
  525         int error;
  526 
  527         error = fget_write(td, fd, &cap_pwrite_rights, &fp);
  528         if (error)
  529                 return (error);
  530         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  531                 error = ESPIPE;
  532         else if (offset < 0 &&
  533             (fp->f_vnode == NULL || fp->f_vnode->v_type != VCHR))
  534                 error = EINVAL;
  535         else
  536                 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET);
  537         fdrop(fp, td);
  538         return (error);
  539 }
  540 
  541 /*
  542  * Common code for writev and pwritev that writes data to
  543  * a file using the passed in uio, offset, and flags.
  544  */
  545 static int
  546 dofilewrite(struct thread *td, int fd, struct file *fp, struct uio *auio,
  547     off_t offset, int flags)
  548 {
  549         ssize_t cnt;
  550         int error;
  551 #ifdef KTRACE
  552         struct uio *ktruio = NULL;
  553 #endif
  554 
  555         AUDIT_ARG_FD(fd);
  556         auio->uio_rw = UIO_WRITE;
  557         auio->uio_td = td;
  558         auio->uio_offset = offset;
  559 #ifdef KTRACE
  560         if (KTRPOINT(td, KTR_GENIO))
  561                 ktruio = cloneuio(auio);
  562 #endif
  563         cnt = auio->uio_resid;
  564         if (fp->f_type == DTYPE_VNODE &&
  565             (fp->f_vnread_flags & FDEVFS_VNODE) == 0)
  566                 bwillwrite();
  567         if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) {
  568                 if (auio->uio_resid != cnt && (error == ERESTART ||
  569                     error == EINTR || error == EWOULDBLOCK))
  570                         error = 0;
  571                 /* Socket layer is responsible for issuing SIGPIPE. */
  572                 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) {
  573                         PROC_LOCK(td->td_proc);
  574                         tdsignal(td, SIGPIPE);
  575                         PROC_UNLOCK(td->td_proc);
  576                 }
  577         }
  578         cnt -= auio->uio_resid;
  579 #ifdef KTRACE
  580         if (ktruio != NULL) {
  581                 ktruio->uio_resid = cnt;
  582                 ktrgenio(fd, UIO_WRITE, ktruio, error);
  583         }
  584 #endif
  585         td->td_retval[0] = cnt;
  586         return (error);
  587 }
  588 
  589 /*
  590  * Truncate a file given a file descriptor.
  591  *
  592  * Can't use fget_write() here, since must return EINVAL and not EBADF if the
  593  * descriptor isn't writable.
  594  */
  595 int
  596 kern_ftruncate(struct thread *td, int fd, off_t length)
  597 {
  598         struct file *fp;
  599         int error;
  600 
  601         AUDIT_ARG_FD(fd);
  602         if (length < 0)
  603                 return (EINVAL);
  604         error = fget(td, fd, &cap_ftruncate_rights, &fp);
  605         if (error)
  606                 return (error);
  607         AUDIT_ARG_FILE(td->td_proc, fp);
  608         if (!(fp->f_flag & FWRITE)) {
  609                 fdrop(fp, td);
  610                 return (EINVAL);
  611         }
  612         error = fo_truncate(fp, length, td->td_ucred, td);
  613         fdrop(fp, td);
  614         return (error);
  615 }
  616 
  617 #ifndef _SYS_SYSPROTO_H_
  618 struct ftruncate_args {
  619         int     fd;
  620         int     pad;
  621         off_t   length;
  622 };
  623 #endif
  624 int
  625 sys_ftruncate(struct thread *td, struct ftruncate_args *uap)
  626 {
  627 
  628         return (kern_ftruncate(td, uap->fd, uap->length));
  629 }
  630 
  631 #if defined(COMPAT_43)
  632 #ifndef _SYS_SYSPROTO_H_
  633 struct oftruncate_args {
  634         int     fd;
  635         long    length;
  636 };
  637 #endif
  638 int
  639 oftruncate(struct thread *td, struct oftruncate_args *uap)
  640 {
  641 
  642         return (kern_ftruncate(td, uap->fd, uap->length));
  643 }
  644 #endif /* COMPAT_43 */
  645 
  646 #ifndef _SYS_SYSPROTO_H_
  647 struct ioctl_args {
  648         int     fd;
  649         u_long  com;
  650         caddr_t data;
  651 };
  652 #endif
  653 /* ARGSUSED */
  654 int
  655 sys_ioctl(struct thread *td, struct ioctl_args *uap)
  656 {
  657         u_char smalldata[SYS_IOCTL_SMALL_SIZE] __aligned(SYS_IOCTL_SMALL_ALIGN);
  658         uint32_t com;
  659         int arg, error;
  660         u_int size;
  661         caddr_t data;
  662 
  663 #ifdef INVARIANTS
  664         if (uap->com > 0xffffffff) {
  665                 printf(
  666                     "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
  667                     td->td_proc->p_pid, td->td_name, uap->com);
  668         }
  669 #endif
  670         com = (uint32_t)uap->com;
  671 
  672         /*
  673          * Interpret high order word to find amount of data to be
  674          * copied to/from the user's address space.
  675          */
  676         size = IOCPARM_LEN(com);
  677         if ((size > IOCPARM_MAX) ||
  678             ((com & (IOC_VOID  | IOC_IN | IOC_OUT)) == 0) ||
  679 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
  680             ((com & IOC_OUT) && size == 0) ||
  681 #else
  682             ((com & (IOC_IN | IOC_OUT)) && size == 0) ||
  683 #endif
  684             ((com & IOC_VOID) && size > 0 && size != sizeof(int)))
  685                 return (ENOTTY);
  686 
  687         if (size > 0) {
  688                 if (com & IOC_VOID) {
  689                         /* Integer argument. */
  690                         arg = (intptr_t)uap->data;
  691                         data = (void *)&arg;
  692                         size = 0;
  693                 } else {
  694                         if (size > SYS_IOCTL_SMALL_SIZE)
  695                                 data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
  696                         else
  697                                 data = smalldata;
  698                 }
  699         } else
  700                 data = (void *)&uap->data;
  701         if (com & IOC_IN) {
  702                 error = copyin(uap->data, data, (u_int)size);
  703                 if (error != 0)
  704                         goto out;
  705         } else if (com & IOC_OUT) {
  706                 /*
  707                  * Zero the buffer so the user always
  708                  * gets back something deterministic.
  709                  */
  710                 bzero(data, size);
  711         }
  712 
  713         error = kern_ioctl(td, uap->fd, com, data);
  714 
  715         if (error == 0 && (com & IOC_OUT))
  716                 error = copyout(data, uap->data, (u_int)size);
  717 
  718 out:
  719         if (size > SYS_IOCTL_SMALL_SIZE)
  720                 free(data, M_IOCTLOPS);
  721         return (error);
  722 }
  723 
  724 int
  725 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
  726 {
  727         struct file *fp;
  728         struct filedesc *fdp;
  729         int error, tmp, locked;
  730 
  731         AUDIT_ARG_FD(fd);
  732         AUDIT_ARG_CMD(com);
  733 
  734         fdp = td->td_proc->p_fd;
  735 
  736         switch (com) {
  737         case FIONCLEX:
  738         case FIOCLEX:
  739                 FILEDESC_XLOCK(fdp);
  740                 locked = LA_XLOCKED;
  741                 break;
  742         default:
  743 #ifdef CAPABILITIES
  744                 FILEDESC_SLOCK(fdp);
  745                 locked = LA_SLOCKED;
  746 #else
  747                 locked = LA_UNLOCKED;
  748 #endif
  749                 break;
  750         }
  751 
  752 #ifdef CAPABILITIES
  753         if ((fp = fget_locked(fdp, fd)) == NULL) {
  754                 error = EBADF;
  755                 goto out;
  756         }
  757         if ((error = cap_ioctl_check(fdp, fd, com)) != 0) {
  758                 fp = NULL;      /* fhold() was not called yet */
  759                 goto out;
  760         }
  761         if (!fhold(fp)) {
  762                 error = EBADF;
  763                 fp = NULL;
  764                 goto out;
  765         }
  766         if (locked == LA_SLOCKED) {
  767                 FILEDESC_SUNLOCK(fdp);
  768                 locked = LA_UNLOCKED;
  769         }
  770 #else
  771         error = fget(td, fd, &cap_ioctl_rights, &fp);
  772         if (error != 0) {
  773                 fp = NULL;
  774                 goto out;
  775         }
  776 #endif
  777         if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
  778                 error = EBADF;
  779                 goto out;
  780         }
  781 
  782         switch (com) {
  783         case FIONCLEX:
  784                 fdp->fd_ofiles[fd].fde_flags &= ~UF_EXCLOSE;
  785                 goto out;
  786         case FIOCLEX:
  787                 fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE;
  788                 goto out;
  789         case FIONBIO:
  790                 if ((tmp = *(int *)data))
  791                         atomic_set_int(&fp->f_flag, FNONBLOCK);
  792                 else
  793                         atomic_clear_int(&fp->f_flag, FNONBLOCK);
  794                 data = (void *)&tmp;
  795                 break;
  796         case FIOASYNC:
  797                 if ((tmp = *(int *)data))
  798                         atomic_set_int(&fp->f_flag, FASYNC);
  799                 else
  800                         atomic_clear_int(&fp->f_flag, FASYNC);
  801                 data = (void *)&tmp;
  802                 break;
  803         }
  804 
  805         error = fo_ioctl(fp, com, data, td->td_ucred, td);
  806 out:
  807         switch (locked) {
  808         case LA_XLOCKED:
  809                 FILEDESC_XUNLOCK(fdp);
  810                 break;
  811 #ifdef CAPABILITIES
  812         case LA_SLOCKED:
  813                 FILEDESC_SUNLOCK(fdp);
  814                 break;
  815 #endif
  816         default:
  817                 FILEDESC_UNLOCK_ASSERT(fdp);
  818                 break;
  819         }
  820         if (fp != NULL)
  821                 fdrop(fp, td);
  822         return (error);
  823 }
  824 
  825 int
  826 poll_no_poll(int events)
  827 {
  828         /*
  829          * Return true for read/write.  If the user asked for something
  830          * special, return POLLNVAL, so that clients have a way of
  831          * determining reliably whether or not the extended
  832          * functionality is present without hard-coding knowledge
  833          * of specific filesystem implementations.
  834          */
  835         if (events & ~POLLSTANDARD)
  836                 return (POLLNVAL);
  837 
  838         return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
  839 }
  840 
  841 int
  842 sys_pselect(struct thread *td, struct pselect_args *uap)
  843 {
  844         struct timespec ts;
  845         struct timeval tv, *tvp;
  846         sigset_t set, *uset;
  847         int error;
  848 
  849         if (uap->ts != NULL) {
  850                 error = copyin(uap->ts, &ts, sizeof(ts));
  851                 if (error != 0)
  852                     return (error);
  853                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
  854                 tvp = &tv;
  855         } else
  856                 tvp = NULL;
  857         if (uap->sm != NULL) {
  858                 error = copyin(uap->sm, &set, sizeof(set));
  859                 if (error != 0)
  860                         return (error);
  861                 uset = &set;
  862         } else
  863                 uset = NULL;
  864         return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  865             uset, NFDBITS));
  866 }
  867 
  868 int
  869 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
  870     struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
  871 {
  872         int error;
  873 
  874         if (uset != NULL) {
  875                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
  876                     &td->td_oldsigmask, 0);
  877                 if (error != 0)
  878                         return (error);
  879                 td->td_pflags |= TDP_OLDMASK;
  880                 /*
  881                  * Make sure that ast() is called on return to
  882                  * usermode and TDP_OLDMASK is cleared, restoring old
  883                  * sigmask.
  884                  */
  885                 thread_lock(td);
  886                 td->td_flags |= TDF_ASTPENDING;
  887                 thread_unlock(td);
  888         }
  889         error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
  890         return (error);
  891 }
  892 
  893 #ifndef _SYS_SYSPROTO_H_
  894 struct select_args {
  895         int     nd;
  896         fd_set  *in, *ou, *ex;
  897         struct  timeval *tv;
  898 };
  899 #endif
  900 int
  901 sys_select(struct thread *td, struct select_args *uap)
  902 {
  903         struct timeval tv, *tvp;
  904         int error;
  905 
  906         if (uap->tv != NULL) {
  907                 error = copyin(uap->tv, &tv, sizeof(tv));
  908                 if (error)
  909                         return (error);
  910                 tvp = &tv;
  911         } else
  912                 tvp = NULL;
  913 
  914         return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  915             NFDBITS));
  916 }
  917 
  918 /*
  919  * In the unlikely case when user specified n greater then the last
  920  * open file descriptor, check that no bits are set after the last
  921  * valid fd.  We must return EBADF if any is set.
  922  *
  923  * There are applications that rely on the behaviour.
  924  *
  925  * nd is fd_lastfile + 1.
  926  */
  927 static int
  928 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits)
  929 {
  930         char *addr, *oaddr;
  931         int b, i, res;
  932         uint8_t bits;
  933 
  934         if (nd >= ndu || fd_in == NULL)
  935                 return (0);
  936 
  937         oaddr = NULL;
  938         bits = 0; /* silence gcc */
  939         for (i = nd; i < ndu; i++) {
  940                 b = i / NBBY;
  941 #if BYTE_ORDER == LITTLE_ENDIAN
  942                 addr = (char *)fd_in + b;
  943 #else
  944                 addr = (char *)fd_in;
  945                 if (abi_nfdbits == NFDBITS) {
  946                         addr += rounddown(b, sizeof(fd_mask)) +
  947                             sizeof(fd_mask) - 1 - b % sizeof(fd_mask);
  948                 } else {
  949                         addr += rounddown(b, sizeof(uint32_t)) +
  950                             sizeof(uint32_t) - 1 - b % sizeof(uint32_t);
  951                 }
  952 #endif
  953                 if (addr != oaddr) {
  954                         res = fubyte(addr);
  955                         if (res == -1)
  956                                 return (EFAULT);
  957                         oaddr = addr;
  958                         bits = res;
  959                 }
  960                 if ((bits & (1 << (i % NBBY))) != 0)
  961                         return (EBADF);
  962         }
  963         return (0);
  964 }
  965 
  966 int
  967 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
  968     fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
  969 {
  970         struct filedesc *fdp;
  971         /*
  972          * The magic 2048 here is chosen to be just enough for FD_SETSIZE
  973          * infds with the new FD_SETSIZE of 1024, and more than enough for
  974          * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
  975          * of 256.
  976          */
  977         fd_mask s_selbits[howmany(2048, NFDBITS)];
  978         fd_mask *ibits[3], *obits[3], *selbits, *sbp;
  979         struct timeval rtv;
  980         sbintime_t asbt, precision, rsbt;
  981         u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
  982         int error, lf, ndu;
  983 
  984         if (nd < 0)
  985                 return (EINVAL);
  986         fdp = td->td_proc->p_fd;
  987         ndu = nd;
  988         lf = fdp->fd_lastfile;
  989         if (nd > lf + 1)
  990                 nd = lf + 1;
  991 
  992         error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits);
  993         if (error != 0)
  994                 return (error);
  995         error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits);
  996         if (error != 0)
  997                 return (error);
  998         error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits);
  999         if (error != 0)
 1000                 return (error);
 1001 
 1002         /*
 1003          * Allocate just enough bits for the non-null fd_sets.  Use the
 1004          * preallocated auto buffer if possible.
 1005          */
 1006         nfdbits = roundup(nd, NFDBITS);
 1007         ncpbytes = nfdbits / NBBY;
 1008         ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
 1009         nbufbytes = 0;
 1010         if (fd_in != NULL)
 1011                 nbufbytes += 2 * ncpbytes;
 1012         if (fd_ou != NULL)
 1013                 nbufbytes += 2 * ncpbytes;
 1014         if (fd_ex != NULL)
 1015                 nbufbytes += 2 * ncpbytes;
 1016         if (nbufbytes <= sizeof s_selbits)
 1017                 selbits = &s_selbits[0];
 1018         else
 1019                 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
 1020 
 1021         /*
 1022          * Assign pointers into the bit buffers and fetch the input bits.
 1023          * Put the output buffers together so that they can be bzeroed
 1024          * together.
 1025          */
 1026         sbp = selbits;
 1027 #define getbits(name, x) \
 1028         do {                                                            \
 1029                 if (name == NULL) {                                     \
 1030                         ibits[x] = NULL;                                \
 1031                         obits[x] = NULL;                                \
 1032                 } else {                                                \
 1033                         ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp;   \
 1034                         obits[x] = sbp;                                 \
 1035                         sbp += ncpbytes / sizeof *sbp;                  \
 1036                         error = copyin(name, ibits[x], ncpubytes);      \
 1037                         if (error != 0)                                 \
 1038                                 goto done;                              \
 1039                         if (ncpbytes != ncpubytes)                      \
 1040                                 bzero((char *)ibits[x] + ncpubytes,     \
 1041                                     ncpbytes - ncpubytes);              \
 1042                 }                                                       \
 1043         } while (0)
 1044         getbits(fd_in, 0);
 1045         getbits(fd_ou, 1);
 1046         getbits(fd_ex, 2);
 1047 #undef  getbits
 1048 
 1049 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
 1050         /*
 1051          * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
 1052          * we are running under 32-bit emulation. This should be more
 1053          * generic.
 1054          */
 1055 #define swizzle_fdset(bits)                                             \
 1056         if (abi_nfdbits != NFDBITS && bits != NULL) {                   \
 1057                 int i;                                                  \
 1058                 for (i = 0; i < ncpbytes / sizeof *sbp; i++)            \
 1059                         bits[i] = (bits[i] >> 32) | (bits[i] << 32);    \
 1060         }
 1061 #else
 1062 #define swizzle_fdset(bits)
 1063 #endif
 1064 
 1065         /* Make sure the bit order makes it through an ABI transition */
 1066         swizzle_fdset(ibits[0]);
 1067         swizzle_fdset(ibits[1]);
 1068         swizzle_fdset(ibits[2]);
 1069         
 1070         if (nbufbytes != 0)
 1071                 bzero(selbits, nbufbytes / 2);
 1072 
 1073         precision = 0;
 1074         if (tvp != NULL) {
 1075                 rtv = *tvp;
 1076                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
 1077                     rtv.tv_usec >= 1000000) {
 1078                         error = EINVAL;
 1079                         goto done;
 1080                 }
 1081                 if (!timevalisset(&rtv))
 1082                         asbt = 0;
 1083                 else if (rtv.tv_sec <= INT32_MAX) {
 1084                         rsbt = tvtosbt(rtv);
 1085                         precision = rsbt;
 1086                         precision >>= tc_precexp;
 1087                         if (TIMESEL(&asbt, rsbt))
 1088                                 asbt += tc_tick_sbt;
 1089                         if (asbt <= SBT_MAX - rsbt)
 1090                                 asbt += rsbt;
 1091                         else
 1092                                 asbt = -1;
 1093                 } else
 1094                         asbt = -1;
 1095         } else
 1096                 asbt = -1;
 1097         seltdinit(td);
 1098         /* Iterate until the timeout expires or descriptors become ready. */
 1099         for (;;) {
 1100                 error = selscan(td, ibits, obits, nd);
 1101                 if (error || td->td_retval[0] != 0)
 1102                         break;
 1103                 error = seltdwait(td, asbt, precision);
 1104                 if (error)
 1105                         break;
 1106                 error = selrescan(td, ibits, obits);
 1107                 if (error || td->td_retval[0] != 0)
 1108                         break;
 1109         }
 1110         seltdclear(td);
 1111 
 1112 done:
 1113         /* select is not restarted after signals... */
 1114         if (error == ERESTART)
 1115                 error = EINTR;
 1116         if (error == EWOULDBLOCK)
 1117                 error = 0;
 1118 
 1119         /* swizzle bit order back, if necessary */
 1120         swizzle_fdset(obits[0]);
 1121         swizzle_fdset(obits[1]);
 1122         swizzle_fdset(obits[2]);
 1123 #undef swizzle_fdset
 1124 
 1125 #define putbits(name, x) \
 1126         if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
 1127                 error = error2;
 1128         if (error == 0) {
 1129                 int error2;
 1130 
 1131                 putbits(fd_in, 0);
 1132                 putbits(fd_ou, 1);
 1133                 putbits(fd_ex, 2);
 1134 #undef putbits
 1135         }
 1136         if (selbits != &s_selbits[0])
 1137                 free(selbits, M_SELECT);
 1138 
 1139         return (error);
 1140 }
 1141 /* 
 1142  * Convert a select bit set to poll flags.
 1143  *
 1144  * The backend always returns POLLHUP/POLLERR if appropriate and we
 1145  * return this as a set bit in any set.
 1146  */
 1147 static int select_flags[3] = {
 1148     POLLRDNORM | POLLHUP | POLLERR,
 1149     POLLWRNORM | POLLHUP | POLLERR,
 1150     POLLRDBAND | POLLERR
 1151 };
 1152 
 1153 /*
 1154  * Compute the fo_poll flags required for a fd given by the index and
 1155  * bit position in the fd_mask array.
 1156  */
 1157 static __inline int
 1158 selflags(fd_mask **ibits, int idx, fd_mask bit)
 1159 {
 1160         int flags;
 1161         int msk;
 1162 
 1163         flags = 0;
 1164         for (msk = 0; msk < 3; msk++) {
 1165                 if (ibits[msk] == NULL)
 1166                         continue;
 1167                 if ((ibits[msk][idx] & bit) == 0)
 1168                         continue;
 1169                 flags |= select_flags[msk];
 1170         }
 1171         return (flags);
 1172 }
 1173 
 1174 /*
 1175  * Set the appropriate output bits given a mask of fired events and the
 1176  * input bits originally requested.
 1177  */
 1178 static __inline int
 1179 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
 1180 {
 1181         int msk;
 1182         int n;
 1183 
 1184         n = 0;
 1185         for (msk = 0; msk < 3; msk++) {
 1186                 if ((events & select_flags[msk]) == 0)
 1187                         continue;
 1188                 if (ibits[msk] == NULL)
 1189                         continue;
 1190                 if ((ibits[msk][idx] & bit) == 0)
 1191                         continue;
 1192                 /*
 1193                  * XXX Check for a duplicate set.  This can occur because a
 1194                  * socket calls selrecord() twice for each poll() call
 1195                  * resulting in two selfds per real fd.  selrescan() will
 1196                  * call selsetbits twice as a result.
 1197                  */
 1198                 if ((obits[msk][idx] & bit) != 0)
 1199                         continue;
 1200                 obits[msk][idx] |= bit;
 1201                 n++;
 1202         }
 1203 
 1204         return (n);
 1205 }
 1206 
 1207 static __inline int
 1208 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp)
 1209 {
 1210 
 1211         return (fget_unlocked(fdp, fd, &cap_event_rights, fpp, NULL));
 1212 }
 1213 
 1214 /*
 1215  * Traverse the list of fds attached to this thread's seltd and check for
 1216  * completion.
 1217  */
 1218 static int
 1219 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
 1220 {
 1221         struct filedesc *fdp;
 1222         struct selinfo *si;
 1223         struct seltd *stp;
 1224         struct selfd *sfp;
 1225         struct selfd *sfn;
 1226         struct file *fp;
 1227         fd_mask bit;
 1228         int fd, ev, n, idx;
 1229         int error;
 1230 
 1231         fdp = td->td_proc->p_fd;
 1232         stp = td->td_sel;
 1233         n = 0;
 1234         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1235                 fd = (int)(uintptr_t)sfp->sf_cookie;
 1236                 si = sfp->sf_si;
 1237                 selfdfree(stp, sfp);
 1238                 /* If the selinfo wasn't cleared the event didn't fire. */
 1239                 if (si != NULL)
 1240                         continue;
 1241                 error = getselfd_cap(fdp, fd, &fp);
 1242                 if (error)
 1243                         return (error);
 1244                 idx = fd / NFDBITS;
 1245                 bit = (fd_mask)1 << (fd % NFDBITS);
 1246                 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
 1247                 fdrop(fp, td);
 1248                 if (ev != 0)
 1249                         n += selsetbits(ibits, obits, idx, bit, ev);
 1250         }
 1251         stp->st_flags = 0;
 1252         td->td_retval[0] = n;
 1253         return (0);
 1254 }
 1255 
 1256 /*
 1257  * Perform the initial filedescriptor scan and register ourselves with
 1258  * each selinfo.
 1259  */
 1260 static int
 1261 selscan(struct thread *td, fd_mask **ibits, fd_mask **obits, int nfd)
 1262 {
 1263         struct filedesc *fdp;
 1264         struct file *fp;
 1265         fd_mask bit;
 1266         int ev, flags, end, fd;
 1267         int n, idx;
 1268         int error;
 1269 
 1270         fdp = td->td_proc->p_fd;
 1271         n = 0;
 1272         for (idx = 0, fd = 0; fd < nfd; idx++) {
 1273                 end = imin(fd + NFDBITS, nfd);
 1274                 for (bit = 1; fd < end; bit <<= 1, fd++) {
 1275                         /* Compute the list of events we're interested in. */
 1276                         flags = selflags(ibits, idx, bit);
 1277                         if (flags == 0)
 1278                                 continue;
 1279                         error = getselfd_cap(fdp, fd, &fp);
 1280                         if (error)
 1281                                 return (error);
 1282                         selfdalloc(td, (void *)(uintptr_t)fd);
 1283                         ev = fo_poll(fp, flags, td->td_ucred, td);
 1284                         fdrop(fp, td);
 1285                         if (ev != 0)
 1286                                 n += selsetbits(ibits, obits, idx, bit, ev);
 1287                 }
 1288         }
 1289 
 1290         td->td_retval[0] = n;
 1291         return (0);
 1292 }
 1293 
 1294 int
 1295 sys_poll(struct thread *td, struct poll_args *uap)
 1296 {
 1297         struct timespec ts, *tsp;
 1298 
 1299         if (uap->timeout != INFTIM) {
 1300                 if (uap->timeout < 0)
 1301                         return (EINVAL);
 1302                 ts.tv_sec = uap->timeout / 1000;
 1303                 ts.tv_nsec = (uap->timeout % 1000) * 1000000;
 1304                 tsp = &ts;
 1305         } else
 1306                 tsp = NULL;
 1307 
 1308         return (kern_poll(td, uap->fds, uap->nfds, tsp, NULL));
 1309 }
 1310 
 1311 int
 1312 kern_poll(struct thread *td, struct pollfd *fds, u_int nfds,
 1313     struct timespec *tsp, sigset_t *uset)
 1314 {
 1315         struct pollfd *bits;
 1316         struct pollfd smallbits[32];
 1317         sbintime_t sbt, precision, tmp;
 1318         time_t over;
 1319         struct timespec ts;
 1320         int error;
 1321         size_t ni;
 1322 
 1323         precision = 0;
 1324         if (tsp != NULL) {
 1325                 if (tsp->tv_sec < 0)
 1326                         return (EINVAL);
 1327                 if (tsp->tv_nsec < 0 || tsp->tv_nsec >= 1000000000)
 1328                         return (EINVAL);
 1329                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
 1330                         sbt = 0;
 1331                 else {
 1332                         ts = *tsp;
 1333                         if (ts.tv_sec > INT32_MAX / 2) {
 1334                                 over = ts.tv_sec - INT32_MAX / 2;
 1335                                 ts.tv_sec -= over;
 1336                         } else
 1337                                 over = 0;
 1338                         tmp = tstosbt(ts);
 1339                         precision = tmp;
 1340                         precision >>= tc_precexp;
 1341                         if (TIMESEL(&sbt, tmp))
 1342                                 sbt += tc_tick_sbt;
 1343                         sbt += tmp;
 1344                 }
 1345         } else
 1346                 sbt = -1;
 1347 
 1348         if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 
 1349                 return (EINVAL);
 1350         ni = nfds * sizeof(struct pollfd);
 1351         if (ni > sizeof(smallbits))
 1352                 bits = malloc(ni, M_TEMP, M_WAITOK);
 1353         else
 1354                 bits = smallbits;
 1355         error = copyin(fds, bits, ni);
 1356         if (error)
 1357                 goto done;
 1358 
 1359         if (uset != NULL) {
 1360                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
 1361                     &td->td_oldsigmask, 0);
 1362                 if (error)
 1363                         goto done;
 1364                 td->td_pflags |= TDP_OLDMASK;
 1365                 /*
 1366                  * Make sure that ast() is called on return to
 1367                  * usermode and TDP_OLDMASK is cleared, restoring old
 1368                  * sigmask.
 1369                  */
 1370                 thread_lock(td);
 1371                 td->td_flags |= TDF_ASTPENDING;
 1372                 thread_unlock(td);
 1373         }
 1374 
 1375         seltdinit(td);
 1376         /* Iterate until the timeout expires or descriptors become ready. */
 1377         for (;;) {
 1378                 error = pollscan(td, bits, nfds);
 1379                 if (error || td->td_retval[0] != 0)
 1380                         break;
 1381                 error = seltdwait(td, sbt, precision);
 1382                 if (error)
 1383                         break;
 1384                 error = pollrescan(td);
 1385                 if (error || td->td_retval[0] != 0)
 1386                         break;
 1387         }
 1388         seltdclear(td);
 1389 
 1390 done:
 1391         /* poll is not restarted after signals... */
 1392         if (error == ERESTART)
 1393                 error = EINTR;
 1394         if (error == EWOULDBLOCK)
 1395                 error = 0;
 1396         if (error == 0) {
 1397                 error = pollout(td, bits, fds, nfds);
 1398                 if (error)
 1399                         goto out;
 1400         }
 1401 out:
 1402         if (ni > sizeof(smallbits))
 1403                 free(bits, M_TEMP);
 1404         return (error);
 1405 }
 1406 
 1407 int
 1408 sys_ppoll(struct thread *td, struct ppoll_args *uap)
 1409 {
 1410         struct timespec ts, *tsp;
 1411         sigset_t set, *ssp;
 1412         int error;
 1413 
 1414         if (uap->ts != NULL) {
 1415                 error = copyin(uap->ts, &ts, sizeof(ts));
 1416                 if (error)
 1417                         return (error);
 1418                 tsp = &ts;
 1419         } else
 1420                 tsp = NULL;
 1421         if (uap->set != NULL) {
 1422                 error = copyin(uap->set, &set, sizeof(set));
 1423                 if (error)
 1424                         return (error);
 1425                 ssp = &set;
 1426         } else
 1427                 ssp = NULL;
 1428         /*
 1429          * fds is still a pointer to user space. kern_poll() will
 1430          * take care of copyin that array to the kernel space.
 1431          */
 1432 
 1433         return (kern_poll(td, uap->fds, uap->nfds, tsp, ssp));
 1434 }
 1435 
 1436 static int
 1437 pollrescan(struct thread *td)
 1438 {
 1439         struct seltd *stp;
 1440         struct selfd *sfp;
 1441         struct selfd *sfn;
 1442         struct selinfo *si;
 1443         struct filedesc *fdp;
 1444         struct file *fp;
 1445         struct pollfd *fd;
 1446         int n;
 1447 
 1448         n = 0;
 1449         fdp = td->td_proc->p_fd;
 1450         stp = td->td_sel;
 1451         FILEDESC_SLOCK(fdp);
 1452         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1453                 fd = (struct pollfd *)sfp->sf_cookie;
 1454                 si = sfp->sf_si;
 1455                 selfdfree(stp, sfp);
 1456                 /* If the selinfo wasn't cleared the event didn't fire. */
 1457                 if (si != NULL)
 1458                         continue;
 1459                 fp = fdp->fd_ofiles[fd->fd].fde_file;
 1460 #ifdef CAPABILITIES
 1461                 if (fp == NULL ||
 1462                     cap_check(cap_rights(fdp, fd->fd), &cap_event_rights) != 0)
 1463 #else
 1464                 if (fp == NULL)
 1465 #endif
 1466                 {
 1467                         fd->revents = POLLNVAL;
 1468                         n++;
 1469                         continue;
 1470                 }
 1471 
 1472                 /*
 1473                  * Note: backend also returns POLLHUP and
 1474                  * POLLERR if appropriate.
 1475                  */
 1476                 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
 1477                 if (fd->revents != 0)
 1478                         n++;
 1479         }
 1480         FILEDESC_SUNLOCK(fdp);
 1481         stp->st_flags = 0;
 1482         td->td_retval[0] = n;
 1483         return (0);
 1484 }
 1485 
 1486 
 1487 static int
 1488 pollout(struct thread *td, struct pollfd *fds, struct pollfd *ufds, u_int nfd)
 1489 {
 1490         int error = 0;
 1491         u_int i = 0;
 1492         u_int n = 0;
 1493 
 1494         for (i = 0; i < nfd; i++) {
 1495                 error = copyout(&fds->revents, &ufds->revents,
 1496                     sizeof(ufds->revents));
 1497                 if (error)
 1498                         return (error);
 1499                 if (fds->revents != 0)
 1500                         n++;
 1501                 fds++;
 1502                 ufds++;
 1503         }
 1504         td->td_retval[0] = n;
 1505         return (0);
 1506 }
 1507 
 1508 static int
 1509 pollscan(struct thread *td, struct pollfd *fds, u_int nfd)
 1510 {
 1511         struct filedesc *fdp = td->td_proc->p_fd;
 1512         struct file *fp;
 1513         int i, n = 0;
 1514 
 1515         FILEDESC_SLOCK(fdp);
 1516         for (i = 0; i < nfd; i++, fds++) {
 1517                 if (fds->fd > fdp->fd_lastfile) {
 1518                         fds->revents = POLLNVAL;
 1519                         n++;
 1520                 } else if (fds->fd < 0) {
 1521                         fds->revents = 0;
 1522                 } else {
 1523                         fp = fdp->fd_ofiles[fds->fd].fde_file;
 1524 #ifdef CAPABILITIES
 1525                         if (fp == NULL ||
 1526                             cap_check(cap_rights(fdp, fds->fd), &cap_event_rights) != 0)
 1527 #else
 1528                         if (fp == NULL)
 1529 #endif
 1530                         {
 1531                                 fds->revents = POLLNVAL;
 1532                                 n++;
 1533                         } else {
 1534                                 /*
 1535                                  * Note: backend also returns POLLHUP and
 1536                                  * POLLERR if appropriate.
 1537                                  */
 1538                                 selfdalloc(td, fds);
 1539                                 fds->revents = fo_poll(fp, fds->events,
 1540                                     td->td_ucred, td);
 1541                                 /*
 1542                                  * POSIX requires POLLOUT to be never
 1543                                  * set simultaneously with POLLHUP.
 1544                                  */
 1545                                 if ((fds->revents & POLLHUP) != 0)
 1546                                         fds->revents &= ~POLLOUT;
 1547 
 1548                                 if (fds->revents != 0)
 1549                                         n++;
 1550                         }
 1551                 }
 1552         }
 1553         FILEDESC_SUNLOCK(fdp);
 1554         td->td_retval[0] = n;
 1555         return (0);
 1556 }
 1557 
 1558 /*
 1559  * XXX This was created specifically to support netncp and netsmb.  This
 1560  * allows the caller to specify a socket to wait for events on.  It returns
 1561  * 0 if any events matched and an error otherwise.  There is no way to
 1562  * determine which events fired.
 1563  */
 1564 int
 1565 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
 1566 {
 1567         struct timeval rtv;
 1568         sbintime_t asbt, precision, rsbt;
 1569         int error;
 1570 
 1571         precision = 0;  /* stupid gcc! */
 1572         if (tvp != NULL) {
 1573                 rtv = *tvp;
 1574                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 || 
 1575                     rtv.tv_usec >= 1000000)
 1576                         return (EINVAL);
 1577                 if (!timevalisset(&rtv))
 1578                         asbt = 0;
 1579                 else if (rtv.tv_sec <= INT32_MAX) {
 1580                         rsbt = tvtosbt(rtv);
 1581                         precision = rsbt;
 1582                         precision >>= tc_precexp;
 1583                         if (TIMESEL(&asbt, rsbt))
 1584                                 asbt += tc_tick_sbt;
 1585                         if (asbt <= SBT_MAX - rsbt)
 1586                                 asbt += rsbt;
 1587                         else
 1588                                 asbt = -1;
 1589                 } else
 1590                         asbt = -1;
 1591         } else
 1592                 asbt = -1;
 1593         seltdinit(td);
 1594         /*
 1595          * Iterate until the timeout expires or the socket becomes ready.
 1596          */
 1597         for (;;) {
 1598                 selfdalloc(td, NULL);
 1599                 error = sopoll(so, events, NULL, td);
 1600                 /* error here is actually the ready events. */
 1601                 if (error)
 1602                         return (0);
 1603                 error = seltdwait(td, asbt, precision);
 1604                 if (error)
 1605                         break;
 1606         }
 1607         seltdclear(td);
 1608         /* XXX Duplicates ncp/smb behavior. */
 1609         if (error == ERESTART)
 1610                 error = 0;
 1611         return (error);
 1612 }
 1613 
 1614 /*
 1615  * Preallocate two selfds associated with 'cookie'.  Some fo_poll routines
 1616  * have two select sets, one for read and another for write.
 1617  */
 1618 static void
 1619 selfdalloc(struct thread *td, void *cookie)
 1620 {
 1621         struct seltd *stp;
 1622 
 1623         stp = td->td_sel;
 1624         if (stp->st_free1 == NULL)
 1625                 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1626         stp->st_free1->sf_td = stp;
 1627         stp->st_free1->sf_cookie = cookie;
 1628         if (stp->st_free2 == NULL)
 1629                 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1630         stp->st_free2->sf_td = stp;
 1631         stp->st_free2->sf_cookie = cookie;
 1632 }
 1633 
 1634 static void
 1635 selfdfree(struct seltd *stp, struct selfd *sfp)
 1636 {
 1637         STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
 1638         if (sfp->sf_si != NULL) {
 1639                 mtx_lock(sfp->sf_mtx);
 1640                 if (sfp->sf_si != NULL) {
 1641                         TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
 1642                         refcount_release(&sfp->sf_refs);
 1643                 }
 1644                 mtx_unlock(sfp->sf_mtx);
 1645         }
 1646         if (refcount_release(&sfp->sf_refs))
 1647                 uma_zfree(selfd_zone, sfp);
 1648 }
 1649 
 1650 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */
 1651 void
 1652 seldrain(struct selinfo *sip)
 1653 {
 1654 
 1655         /*
 1656          * This feature is already provided by doselwakeup(), thus it is
 1657          * enough to go for it.
 1658          * Eventually, the context, should take care to avoid races
 1659          * between thread calling select()/poll() and file descriptor
 1660          * detaching, but, again, the races are just the same as
 1661          * selwakeup().
 1662          */
 1663         doselwakeup(sip, -1);
 1664 }
 1665 
 1666 /*
 1667  * Record a select request.
 1668  */
 1669 void
 1670 selrecord(struct thread *selector, struct selinfo *sip)
 1671 {
 1672         struct selfd *sfp;
 1673         struct seltd *stp;
 1674         struct mtx *mtxp;
 1675 
 1676         stp = selector->td_sel;
 1677         /*
 1678          * Don't record when doing a rescan.
 1679          */
 1680         if (stp->st_flags & SELTD_RESCAN)
 1681                 return;
 1682         /*
 1683          * Grab one of the preallocated descriptors.
 1684          */
 1685         sfp = NULL;
 1686         if ((sfp = stp->st_free1) != NULL)
 1687                 stp->st_free1 = NULL;
 1688         else if ((sfp = stp->st_free2) != NULL)
 1689                 stp->st_free2 = NULL;
 1690         else
 1691                 panic("selrecord: No free selfd on selq");
 1692         mtxp = sip->si_mtx;
 1693         if (mtxp == NULL)
 1694                 mtxp = mtx_pool_find(mtxpool_select, sip);
 1695         /*
 1696          * Initialize the sfp and queue it in the thread.
 1697          */
 1698         sfp->sf_si = sip;
 1699         sfp->sf_mtx = mtxp;
 1700         refcount_init(&sfp->sf_refs, 2);
 1701         STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
 1702         /*
 1703          * Now that we've locked the sip, check for initialization.
 1704          */
 1705         mtx_lock(mtxp);
 1706         if (sip->si_mtx == NULL) {
 1707                 sip->si_mtx = mtxp;
 1708                 TAILQ_INIT(&sip->si_tdlist);
 1709         }
 1710         /*
 1711          * Add this thread to the list of selfds listening on this selinfo.
 1712          */
 1713         TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
 1714         mtx_unlock(sip->si_mtx);
 1715 }
 1716 
 1717 /* Wake up a selecting thread. */
 1718 void
 1719 selwakeup(struct selinfo *sip)
 1720 {
 1721         doselwakeup(sip, -1);
 1722 }
 1723 
 1724 /* Wake up a selecting thread, and set its priority. */
 1725 void
 1726 selwakeuppri(struct selinfo *sip, int pri)
 1727 {
 1728         doselwakeup(sip, pri);
 1729 }
 1730 
 1731 /*
 1732  * Do a wakeup when a selectable event occurs.
 1733  */
 1734 static void
 1735 doselwakeup(struct selinfo *sip, int pri)
 1736 {
 1737         struct selfd *sfp;
 1738         struct selfd *sfn;
 1739         struct seltd *stp;
 1740 
 1741         /* If it's not initialized there can't be any waiters. */
 1742         if (sip->si_mtx == NULL)
 1743                 return;
 1744         /*
 1745          * Locking the selinfo locks all selfds associated with it.
 1746          */
 1747         mtx_lock(sip->si_mtx);
 1748         TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
 1749                 /*
 1750                  * Once we remove this sfp from the list and clear the
 1751                  * sf_si seltdclear will know to ignore this si.
 1752                  */
 1753                 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
 1754                 sfp->sf_si = NULL;
 1755                 stp = sfp->sf_td;
 1756                 mtx_lock(&stp->st_mtx);
 1757                 stp->st_flags |= SELTD_PENDING;
 1758                 cv_broadcastpri(&stp->st_wait, pri);
 1759                 mtx_unlock(&stp->st_mtx);
 1760                 if (refcount_release(&sfp->sf_refs))
 1761                         uma_zfree(selfd_zone, sfp);
 1762         }
 1763         mtx_unlock(sip->si_mtx);
 1764 }
 1765 
 1766 static void
 1767 seltdinit(struct thread *td)
 1768 {
 1769         struct seltd *stp;
 1770 
 1771         if ((stp = td->td_sel) != NULL)
 1772                 goto out;
 1773         td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
 1774         mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
 1775         cv_init(&stp->st_wait, "select");
 1776 out:
 1777         stp->st_flags = 0;
 1778         STAILQ_INIT(&stp->st_selq);
 1779 }
 1780 
 1781 static int
 1782 seltdwait(struct thread *td, sbintime_t sbt, sbintime_t precision)
 1783 {
 1784         struct seltd *stp;
 1785         int error;
 1786 
 1787         stp = td->td_sel;
 1788         /*
 1789          * An event of interest may occur while we do not hold the seltd
 1790          * locked so check the pending flag before we sleep.
 1791          */
 1792         mtx_lock(&stp->st_mtx);
 1793         /*
 1794          * Any further calls to selrecord will be a rescan.
 1795          */
 1796         stp->st_flags |= SELTD_RESCAN;
 1797         if (stp->st_flags & SELTD_PENDING) {
 1798                 mtx_unlock(&stp->st_mtx);
 1799                 return (0);
 1800         }
 1801         if (sbt == 0)
 1802                 error = EWOULDBLOCK;
 1803         else if (sbt != -1)
 1804                 error = cv_timedwait_sig_sbt(&stp->st_wait, &stp->st_mtx,
 1805                     sbt, precision, C_ABSOLUTE);
 1806         else
 1807                 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
 1808         mtx_unlock(&stp->st_mtx);
 1809 
 1810         return (error);
 1811 }
 1812 
 1813 void
 1814 seltdfini(struct thread *td)
 1815 {
 1816         struct seltd *stp;
 1817 
 1818         stp = td->td_sel;
 1819         if (stp == NULL)
 1820                 return;
 1821         if (stp->st_free1)
 1822                 uma_zfree(selfd_zone, stp->st_free1);
 1823         if (stp->st_free2)
 1824                 uma_zfree(selfd_zone, stp->st_free2);
 1825         td->td_sel = NULL;
 1826         cv_destroy(&stp->st_wait);
 1827         mtx_destroy(&stp->st_mtx);
 1828         free(stp, M_SELECT);
 1829 }
 1830 
 1831 /*
 1832  * Remove the references to the thread from all of the objects we were
 1833  * polling.
 1834  */
 1835 static void
 1836 seltdclear(struct thread *td)
 1837 {
 1838         struct seltd *stp;
 1839         struct selfd *sfp;
 1840         struct selfd *sfn;
 1841 
 1842         stp = td->td_sel;
 1843         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
 1844                 selfdfree(stp, sfp);
 1845         stp->st_flags = 0;
 1846 }
 1847 
 1848 static void selectinit(void *);
 1849 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
 1850 static void
 1851 selectinit(void *dummy __unused)
 1852 {
 1853 
 1854         selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
 1855             NULL, NULL, UMA_ALIGN_PTR, 0);
 1856         mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
 1857 }
 1858 
 1859 /*
 1860  * Set up a syscall return value that follows the convention specified for
 1861  * posix_* functions.
 1862  */
 1863 int
 1864 kern_posix_error(struct thread *td, int error)
 1865 {
 1866 
 1867         if (error <= 0)
 1868                 return (error);
 1869         td->td_errno = error;
 1870         td->td_pflags |= TDP_NERRNO;
 1871         td->td_retval[0] = error;
 1872         return (0);
 1873 }

Cache object: 3b76b8a964595d6a0ce234ab88732a82


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.