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

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1989, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)sys_generic.c       8.5 (Berkeley) 1/21/94
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD: stable/11/sys/kern/sys_generic.c 360331 2020-04-26 08:34:52Z hselasky $");
   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/capsicum.h>
   48 #include <sys/filedesc.h>
   49 #include <sys/filio.h>
   50 #include <sys/fcntl.h>
   51 #include <sys/file.h>
   52 #include <sys/lock.h>
   53 #include <sys/proc.h>
   54 #include <sys/signalvar.h>
   55 #include <sys/socketvar.h>
   56 #include <sys/uio.h>
   57 #include <sys/kernel.h>
   58 #include <sys/ktr.h>
   59 #include <sys/limits.h>
   60 #include <sys/malloc.h>
   61 #include <sys/poll.h>
   62 #include <sys/resourcevar.h>
   63 #include <sys/selinfo.h>
   64 #include <sys/sleepqueue.h>
   65 #include <sys/syscallsubr.h>
   66 #include <sys/sysctl.h>
   67 #include <sys/sysent.h>
   68 #include <sys/vnode.h>
   69 #include <sys/bio.h>
   70 #include <sys/buf.h>
   71 #include <sys/condvar.h>
   72 #ifdef KTRACE
   73 #include <sys/ktrace.h>
   74 #endif
   75 
   76 #include <security/audit/audit.h>
   77 
   78 /*
   79  * The following macro defines how many bytes will be allocated from
   80  * the stack instead of memory allocated when passing the IOCTL data
   81  * structures from userspace and to the kernel. Some IOCTLs having
   82  * small data structures are used very frequently and this small
   83  * buffer on the stack gives a significant speedup improvement for
   84  * those requests. The value of this define should be greater or equal
   85  * to 64 bytes and should also be power of two. The data structure is
   86  * currently hard-aligned to a 8-byte boundary on the stack. This
   87  * should currently be sufficient for all supported platforms.
   88  */
   89 #define SYS_IOCTL_SMALL_SIZE    128     /* bytes */
   90 #define SYS_IOCTL_SMALL_ALIGN   8       /* bytes */
   91 
   92 #ifdef __LP64__
   93 static int iosize_max_clamp = 0;
   94 SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW,
   95     &iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX");
   96 static int devfs_iosize_max_clamp = 1;
   97 SYSCTL_INT(_debug, OID_AUTO, devfs_iosize_max_clamp, CTLFLAG_RW,
   98     &devfs_iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX for devices");
   99 #endif
  100 
  101 /*
  102  * Assert that the return value of read(2) and write(2) syscalls fits
  103  * into a register.  If not, an architecture will need to provide the
  104  * usermode wrappers to reconstruct the result.
  105  */
  106 CTASSERT(sizeof(register_t) >= sizeof(size_t));
  107 
  108 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer");
  109 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer");
  110 MALLOC_DEFINE(M_IOV, "iov", "large iov's");
  111 
  112 static int      pollout(struct thread *, struct pollfd *, struct pollfd *,
  113                     u_int);
  114 static int      pollscan(struct thread *, struct pollfd *, u_int);
  115 static int      pollrescan(struct thread *);
  116 static int      selscan(struct thread *, fd_mask **, fd_mask **, int);
  117 static int      selrescan(struct thread *, fd_mask **, fd_mask **);
  118 static void     selfdalloc(struct thread *, void *);
  119 static void     selfdfree(struct seltd *, struct selfd *);
  120 static int      dofileread(struct thread *, int, struct file *, struct uio *,
  121                     off_t, int);
  122 static int      dofilewrite(struct thread *, int, struct file *, struct uio *,
  123                     off_t, int);
  124 static void     doselwakeup(struct selinfo *, int);
  125 static void     seltdinit(struct thread *);
  126 static int      seltdwait(struct thread *, sbintime_t, sbintime_t);
  127 static void     seltdclear(struct thread *);
  128 
  129 /*
  130  * One seltd per-thread allocated on demand as needed.
  131  *
  132  *      t - protected by st_mtx
  133  *      k - Only accessed by curthread or read-only
  134  */
  135 struct seltd {
  136         STAILQ_HEAD(, selfd)    st_selq;        /* (k) List of selfds. */
  137         struct selfd            *st_free1;      /* (k) free fd for read set. */
  138         struct selfd            *st_free2;      /* (k) free fd for write set. */
  139         struct mtx              st_mtx;         /* Protects struct seltd */
  140         struct cv               st_wait;        /* (t) Wait channel. */
  141         int                     st_flags;       /* (t) SELTD_ flags. */
  142 };
  143 
  144 #define SELTD_PENDING   0x0001                  /* We have pending events. */
  145 #define SELTD_RESCAN    0x0002                  /* Doing a rescan. */
  146 
  147 /*
  148  * One selfd allocated per-thread per-file-descriptor.
  149  *      f - protected by sf_mtx
  150  */
  151 struct selfd {
  152         STAILQ_ENTRY(selfd)     sf_link;        /* (k) fds owned by this td. */
  153         TAILQ_ENTRY(selfd)      sf_threads;     /* (f) fds on this selinfo. */
  154         struct selinfo          *sf_si;         /* (f) selinfo when linked. */
  155         struct mtx              *sf_mtx;        /* Pointer to selinfo mtx. */
  156         struct seltd            *sf_td;         /* (k) owning seltd. */
  157         void                    *sf_cookie;     /* (k) fd or pollfd. */
  158         u_int                   sf_refs;
  159 };
  160 
  161 static uma_zone_t selfd_zone;
  162 static struct mtx_pool *mtxpool_select;
  163 
  164 #ifdef __LP64__
  165 size_t
  166 devfs_iosize_max(void)
  167 {
  168 
  169         return (devfs_iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ?
  170             INT_MAX : SSIZE_MAX);
  171 }
  172 
  173 size_t
  174 iosize_max(void)
  175 {
  176 
  177         return (iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ?
  178             INT_MAX : SSIZE_MAX);
  179 }
  180 #endif
  181 
  182 #ifndef _SYS_SYSPROTO_H_
  183 struct read_args {
  184         int     fd;
  185         void    *buf;
  186         size_t  nbyte;
  187 };
  188 #endif
  189 int
  190 sys_read(td, uap)
  191         struct thread *td;
  192         struct read_args *uap;
  193 {
  194         struct uio auio;
  195         struct iovec aiov;
  196         int error;
  197 
  198         if (uap->nbyte > IOSIZE_MAX)
  199                 return (EINVAL);
  200         aiov.iov_base = uap->buf;
  201         aiov.iov_len = uap->nbyte;
  202         auio.uio_iov = &aiov;
  203         auio.uio_iovcnt = 1;
  204         auio.uio_resid = uap->nbyte;
  205         auio.uio_segflg = UIO_USERSPACE;
  206         error = kern_readv(td, uap->fd, &auio);
  207         return(error);
  208 }
  209 
  210 /*
  211  * Positioned read system call
  212  */
  213 #ifndef _SYS_SYSPROTO_H_
  214 struct pread_args {
  215         int     fd;
  216         void    *buf;
  217         size_t  nbyte;
  218         int     pad;
  219         off_t   offset;
  220 };
  221 #endif
  222 int
  223 sys_pread(struct thread *td, struct pread_args *uap)
  224 {
  225 
  226         return (kern_pread(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
  227 }
  228 
  229 int
  230 kern_pread(struct thread *td, int fd, void *buf, size_t nbyte, off_t offset)
  231 {
  232         struct uio auio;
  233         struct iovec aiov;
  234         int error;
  235 
  236         if (nbyte > IOSIZE_MAX)
  237                 return (EINVAL);
  238         aiov.iov_base = buf;
  239         aiov.iov_len = nbyte;
  240         auio.uio_iov = &aiov;
  241         auio.uio_iovcnt = 1;
  242         auio.uio_resid = nbyte;
  243         auio.uio_segflg = UIO_USERSPACE;
  244         error = kern_preadv(td, fd, &auio, offset);
  245         return (error);
  246 }
  247 
  248 #if defined(COMPAT_FREEBSD6)
  249 int
  250 freebsd6_pread(struct thread *td, struct freebsd6_pread_args *uap)
  251 {
  252 
  253         return (kern_pread(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
  254 }
  255 #endif
  256 
  257 /*
  258  * Scatter read system call.
  259  */
  260 #ifndef _SYS_SYSPROTO_H_
  261 struct readv_args {
  262         int     fd;
  263         struct  iovec *iovp;
  264         u_int   iovcnt;
  265 };
  266 #endif
  267 int
  268 sys_readv(struct thread *td, struct readv_args *uap)
  269 {
  270         struct uio *auio;
  271         int error;
  272 
  273         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  274         if (error)
  275                 return (error);
  276         error = kern_readv(td, uap->fd, auio);
  277         free(auio, M_IOV);
  278         return (error);
  279 }
  280 
  281 int
  282 kern_readv(struct thread *td, int fd, struct uio *auio)
  283 {
  284         struct file *fp;
  285         cap_rights_t rights;
  286         int error;
  287 
  288         error = fget_read(td, fd, cap_rights_init(&rights, CAP_READ), &fp);
  289         if (error)
  290                 return (error);
  291         error = dofileread(td, fd, fp, auio, (off_t)-1, 0);
  292         fdrop(fp, td);
  293         return (error);
  294 }
  295 
  296 /*
  297  * Scatter positioned read system call.
  298  */
  299 #ifndef _SYS_SYSPROTO_H_
  300 struct preadv_args {
  301         int     fd;
  302         struct  iovec *iovp;
  303         u_int   iovcnt;
  304         off_t   offset;
  305 };
  306 #endif
  307 int
  308 sys_preadv(struct thread *td, struct preadv_args *uap)
  309 {
  310         struct uio *auio;
  311         int error;
  312 
  313         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  314         if (error)
  315                 return (error);
  316         error = kern_preadv(td, uap->fd, auio, uap->offset);
  317         free(auio, M_IOV);
  318         return (error);
  319 }
  320 
  321 int
  322 kern_preadv(td, fd, auio, offset)
  323         struct thread *td;
  324         int fd;
  325         struct uio *auio;
  326         off_t offset;
  327 {
  328         struct file *fp;
  329         cap_rights_t rights;
  330         int error;
  331 
  332         error = fget_read(td, fd, cap_rights_init(&rights, CAP_PREAD), &fp);
  333         if (error)
  334                 return (error);
  335         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  336                 error = ESPIPE;
  337         else if (offset < 0 &&
  338             (fp->f_vnode == NULL || fp->f_vnode->v_type != VCHR))
  339                 error = EINVAL;
  340         else
  341                 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET);
  342         fdrop(fp, td);
  343         return (error);
  344 }
  345 
  346 /*
  347  * Common code for readv and preadv that reads data in
  348  * from a file using the passed in uio, offset, and flags.
  349  */
  350 static int
  351 dofileread(td, fd, fp, auio, offset, flags)
  352         struct thread *td;
  353         int fd;
  354         struct file *fp;
  355         struct uio *auio;
  356         off_t offset;
  357         int flags;
  358 {
  359         ssize_t cnt;
  360         int error;
  361 #ifdef KTRACE
  362         struct uio *ktruio = NULL;
  363 #endif
  364 
  365         AUDIT_ARG_FD(fd);
  366 
  367         /* Finish zero length reads right here */
  368         if (auio->uio_resid == 0) {
  369                 td->td_retval[0] = 0;
  370                 return(0);
  371         }
  372         auio->uio_rw = UIO_READ;
  373         auio->uio_offset = offset;
  374         auio->uio_td = td;
  375 #ifdef KTRACE
  376         if (KTRPOINT(td, KTR_GENIO)) 
  377                 ktruio = cloneuio(auio);
  378 #endif
  379         cnt = auio->uio_resid;
  380         if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) {
  381                 if (auio->uio_resid != cnt && (error == ERESTART ||
  382                     error == EINTR || error == EWOULDBLOCK))
  383                         error = 0;
  384         }
  385         cnt -= auio->uio_resid;
  386 #ifdef KTRACE
  387         if (ktruio != NULL) {
  388                 ktruio->uio_resid = cnt;
  389                 ktrgenio(fd, UIO_READ, ktruio, error);
  390         }
  391 #endif
  392         td->td_retval[0] = cnt;
  393         return (error);
  394 }
  395 
  396 #ifndef _SYS_SYSPROTO_H_
  397 struct write_args {
  398         int     fd;
  399         const void *buf;
  400         size_t  nbyte;
  401 };
  402 #endif
  403 int
  404 sys_write(td, uap)
  405         struct thread *td;
  406         struct write_args *uap;
  407 {
  408         struct uio auio;
  409         struct iovec aiov;
  410         int error;
  411 
  412         if (uap->nbyte > IOSIZE_MAX)
  413                 return (EINVAL);
  414         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  415         aiov.iov_len = uap->nbyte;
  416         auio.uio_iov = &aiov;
  417         auio.uio_iovcnt = 1;
  418         auio.uio_resid = uap->nbyte;
  419         auio.uio_segflg = UIO_USERSPACE;
  420         error = kern_writev(td, uap->fd, &auio);
  421         return(error);
  422 }
  423 
  424 /*
  425  * Positioned write system call.
  426  */
  427 #ifndef _SYS_SYSPROTO_H_
  428 struct pwrite_args {
  429         int     fd;
  430         const void *buf;
  431         size_t  nbyte;
  432         int     pad;
  433         off_t   offset;
  434 };
  435 #endif
  436 int
  437 sys_pwrite(struct thread *td, struct pwrite_args *uap)
  438 {
  439 
  440         return (kern_pwrite(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
  441 }
  442 
  443 int
  444 kern_pwrite(struct thread *td, int fd, const void *buf, size_t nbyte,
  445     off_t offset)
  446 {
  447         struct uio auio;
  448         struct iovec aiov;
  449         int error;
  450 
  451         if (nbyte > IOSIZE_MAX)
  452                 return (EINVAL);
  453         aiov.iov_base = (void *)(uintptr_t)buf;
  454         aiov.iov_len = nbyte;
  455         auio.uio_iov = &aiov;
  456         auio.uio_iovcnt = 1;
  457         auio.uio_resid = nbyte;
  458         auio.uio_segflg = UIO_USERSPACE;
  459         error = kern_pwritev(td, fd, &auio, offset);
  460         return(error);
  461 }
  462 
  463 #if defined(COMPAT_FREEBSD6)
  464 int
  465 freebsd6_pwrite(struct thread *td, struct freebsd6_pwrite_args *uap)
  466 {
  467 
  468         return (kern_pwrite(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
  469 }
  470 #endif
  471 
  472 /*
  473  * Gather write system call.
  474  */
  475 #ifndef _SYS_SYSPROTO_H_
  476 struct writev_args {
  477         int     fd;
  478         struct  iovec *iovp;
  479         u_int   iovcnt;
  480 };
  481 #endif
  482 int
  483 sys_writev(struct thread *td, struct writev_args *uap)
  484 {
  485         struct uio *auio;
  486         int error;
  487 
  488         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  489         if (error)
  490                 return (error);
  491         error = kern_writev(td, uap->fd, auio);
  492         free(auio, M_IOV);
  493         return (error);
  494 }
  495 
  496 int
  497 kern_writev(struct thread *td, int fd, struct uio *auio)
  498 {
  499         struct file *fp;
  500         cap_rights_t rights;
  501         int error;
  502 
  503         error = fget_write(td, fd, cap_rights_init(&rights, CAP_WRITE), &fp);
  504         if (error)
  505                 return (error);
  506         error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0);
  507         fdrop(fp, td);
  508         return (error);
  509 }
  510 
  511 /*
  512  * Gather positioned write system call.
  513  */
  514 #ifndef _SYS_SYSPROTO_H_
  515 struct pwritev_args {
  516         int     fd;
  517         struct  iovec *iovp;
  518         u_int   iovcnt;
  519         off_t   offset;
  520 };
  521 #endif
  522 int
  523 sys_pwritev(struct thread *td, struct pwritev_args *uap)
  524 {
  525         struct uio *auio;
  526         int error;
  527 
  528         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  529         if (error)
  530                 return (error);
  531         error = kern_pwritev(td, uap->fd, auio, uap->offset);
  532         free(auio, M_IOV);
  533         return (error);
  534 }
  535 
  536 int
  537 kern_pwritev(td, fd, auio, offset)
  538         struct thread *td;
  539         struct uio *auio;
  540         int fd;
  541         off_t offset;
  542 {
  543         struct file *fp;
  544         cap_rights_t rights;
  545         int error;
  546 
  547         error = fget_write(td, fd, cap_rights_init(&rights, CAP_PWRITE), &fp);
  548         if (error)
  549                 return (error);
  550         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  551                 error = ESPIPE;
  552         else if (offset < 0 &&
  553             (fp->f_vnode == NULL || fp->f_vnode->v_type != VCHR))
  554                 error = EINVAL;
  555         else
  556                 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET);
  557         fdrop(fp, td);
  558         return (error);
  559 }
  560 
  561 /*
  562  * Common code for writev and pwritev that writes data to
  563  * a file using the passed in uio, offset, and flags.
  564  */
  565 static int
  566 dofilewrite(td, fd, fp, auio, offset, flags)
  567         struct thread *td;
  568         int fd;
  569         struct file *fp;
  570         struct uio *auio;
  571         off_t offset;
  572         int flags;
  573 {
  574         ssize_t cnt;
  575         int error;
  576 #ifdef KTRACE
  577         struct uio *ktruio = NULL;
  578 #endif
  579 
  580         AUDIT_ARG_FD(fd);
  581         auio->uio_rw = UIO_WRITE;
  582         auio->uio_td = td;
  583         auio->uio_offset = offset;
  584 #ifdef KTRACE
  585         if (KTRPOINT(td, KTR_GENIO))
  586                 ktruio = cloneuio(auio);
  587 #endif
  588         cnt = auio->uio_resid;
  589         if (fp->f_type == DTYPE_VNODE &&
  590             (fp->f_vnread_flags & FDEVFS_VNODE) == 0)
  591                 bwillwrite();
  592         if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) {
  593                 if (auio->uio_resid != cnt && (error == ERESTART ||
  594                     error == EINTR || error == EWOULDBLOCK))
  595                         error = 0;
  596                 /* Socket layer is responsible for issuing SIGPIPE. */
  597                 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) {
  598                         PROC_LOCK(td->td_proc);
  599                         tdsignal(td, SIGPIPE);
  600                         PROC_UNLOCK(td->td_proc);
  601                 }
  602         }
  603         cnt -= auio->uio_resid;
  604 #ifdef KTRACE
  605         if (ktruio != NULL) {
  606                 ktruio->uio_resid = cnt;
  607                 ktrgenio(fd, UIO_WRITE, ktruio, error);
  608         }
  609 #endif
  610         td->td_retval[0] = cnt;
  611         return (error);
  612 }
  613 
  614 /*
  615  * Truncate a file given a file descriptor.
  616  *
  617  * Can't use fget_write() here, since must return EINVAL and not EBADF if the
  618  * descriptor isn't writable.
  619  */
  620 int
  621 kern_ftruncate(td, fd, length)
  622         struct thread *td;
  623         int fd;
  624         off_t length;
  625 {
  626         struct file *fp;
  627         cap_rights_t rights;
  628         int error;
  629 
  630         AUDIT_ARG_FD(fd);
  631         if (length < 0)
  632                 return (EINVAL);
  633         error = fget(td, fd, cap_rights_init(&rights, CAP_FTRUNCATE), &fp);
  634         if (error)
  635                 return (error);
  636         AUDIT_ARG_FILE(td->td_proc, fp);
  637         if (!(fp->f_flag & FWRITE)) {
  638                 fdrop(fp, td);
  639                 return (EINVAL);
  640         }
  641         error = fo_truncate(fp, length, td->td_ucred, td);
  642         fdrop(fp, td);
  643         return (error);
  644 }
  645 
  646 #ifndef _SYS_SYSPROTO_H_
  647 struct ftruncate_args {
  648         int     fd;
  649         int     pad;
  650         off_t   length;
  651 };
  652 #endif
  653 int
  654 sys_ftruncate(td, uap)
  655         struct thread *td;
  656         struct ftruncate_args *uap;
  657 {
  658 
  659         return (kern_ftruncate(td, uap->fd, uap->length));
  660 }
  661 
  662 #if defined(COMPAT_43)
  663 #ifndef _SYS_SYSPROTO_H_
  664 struct oftruncate_args {
  665         int     fd;
  666         long    length;
  667 };
  668 #endif
  669 int
  670 oftruncate(td, uap)
  671         struct thread *td;
  672         struct oftruncate_args *uap;
  673 {
  674 
  675         return (kern_ftruncate(td, uap->fd, uap->length));
  676 }
  677 #endif /* COMPAT_43 */
  678 
  679 #ifndef _SYS_SYSPROTO_H_
  680 struct ioctl_args {
  681         int     fd;
  682         u_long  com;
  683         caddr_t data;
  684 };
  685 #endif
  686 /* ARGSUSED */
  687 int
  688 sys_ioctl(struct thread *td, struct ioctl_args *uap)
  689 {
  690         u_char smalldata[SYS_IOCTL_SMALL_SIZE] __aligned(SYS_IOCTL_SMALL_ALIGN);
  691         uint32_t com;
  692         int arg, error;
  693         u_int size;
  694         caddr_t data;
  695 
  696 #ifdef INVARIANTS
  697         if (uap->com > 0xffffffff) {
  698                 printf(
  699                     "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
  700                     td->td_proc->p_pid, td->td_name, uap->com);
  701         }
  702 #endif
  703         com = (uint32_t)uap->com;
  704 
  705         /*
  706          * Interpret high order word to find amount of data to be
  707          * copied to/from the user's address space.
  708          */
  709         size = IOCPARM_LEN(com);
  710         if ((size > IOCPARM_MAX) ||
  711             ((com & (IOC_VOID  | IOC_IN | IOC_OUT)) == 0) ||
  712 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
  713             ((com & IOC_OUT) && size == 0) ||
  714 #else
  715             ((com & (IOC_IN | IOC_OUT)) && size == 0) ||
  716 #endif
  717             ((com & IOC_VOID) && size > 0 && size != sizeof(int)))
  718                 return (ENOTTY);
  719 
  720         if (size > 0) {
  721                 if (com & IOC_VOID) {
  722                         /* Integer argument. */
  723                         arg = (intptr_t)uap->data;
  724                         data = (void *)&arg;
  725                         size = 0;
  726                 } else {
  727                         if (size > SYS_IOCTL_SMALL_SIZE)
  728                                 data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
  729                         else
  730                                 data = smalldata;
  731                 }
  732         } else
  733                 data = (void *)&uap->data;
  734         if (com & IOC_IN) {
  735                 error = copyin(uap->data, data, (u_int)size);
  736                 if (error != 0)
  737                         goto out;
  738         } else if (com & IOC_OUT) {
  739                 /*
  740                  * Zero the buffer so the user always
  741                  * gets back something deterministic.
  742                  */
  743                 bzero(data, size);
  744         }
  745 
  746         error = kern_ioctl(td, uap->fd, com, data);
  747 
  748         if (error == 0 && (com & IOC_OUT))
  749                 error = copyout(data, uap->data, (u_int)size);
  750 
  751 out:
  752         if (size > SYS_IOCTL_SMALL_SIZE)
  753                 free(data, M_IOCTLOPS);
  754         return (error);
  755 }
  756 
  757 int
  758 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
  759 {
  760         struct file *fp;
  761         struct filedesc *fdp;
  762 #ifndef CAPABILITIES
  763         cap_rights_t rights;
  764 #endif
  765         int error, tmp, locked;
  766 
  767         AUDIT_ARG_FD(fd);
  768         AUDIT_ARG_CMD(com);
  769 
  770         fdp = td->td_proc->p_fd;
  771 
  772         switch (com) {
  773         case FIONCLEX:
  774         case FIOCLEX:
  775                 FILEDESC_XLOCK(fdp);
  776                 locked = LA_XLOCKED;
  777                 break;
  778         default:
  779 #ifdef CAPABILITIES
  780                 FILEDESC_SLOCK(fdp);
  781                 locked = LA_SLOCKED;
  782 #else
  783                 locked = LA_UNLOCKED;
  784 #endif
  785                 break;
  786         }
  787 
  788 #ifdef CAPABILITIES
  789         if ((fp = fget_locked(fdp, fd)) == NULL) {
  790                 error = EBADF;
  791                 goto out;
  792         }
  793         if ((error = cap_ioctl_check(fdp, fd, com)) != 0) {
  794                 fp = NULL;      /* fhold() was not called yet */
  795                 goto out;
  796         }
  797         fhold(fp);
  798         if (locked == LA_SLOCKED) {
  799                 FILEDESC_SUNLOCK(fdp);
  800                 locked = LA_UNLOCKED;
  801         }
  802 #else
  803         error = fget(td, fd, cap_rights_init(&rights, CAP_IOCTL), &fp);
  804         if (error != 0) {
  805                 fp = NULL;
  806                 goto out;
  807         }
  808 #endif
  809         if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
  810                 error = EBADF;
  811                 goto out;
  812         }
  813 
  814         switch (com) {
  815         case FIONCLEX:
  816                 fdp->fd_ofiles[fd].fde_flags &= ~UF_EXCLOSE;
  817                 goto out;
  818         case FIOCLEX:
  819                 fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE;
  820                 goto out;
  821         case FIONBIO:
  822                 if ((tmp = *(int *)data))
  823                         atomic_set_int(&fp->f_flag, FNONBLOCK);
  824                 else
  825                         atomic_clear_int(&fp->f_flag, FNONBLOCK);
  826                 data = (void *)&tmp;
  827                 break;
  828         case FIOASYNC:
  829                 if ((tmp = *(int *)data))
  830                         atomic_set_int(&fp->f_flag, FASYNC);
  831                 else
  832                         atomic_clear_int(&fp->f_flag, FASYNC);
  833                 data = (void *)&tmp;
  834                 break;
  835         }
  836 
  837         error = fo_ioctl(fp, com, data, td->td_ucred, td);
  838 out:
  839         switch (locked) {
  840         case LA_XLOCKED:
  841                 FILEDESC_XUNLOCK(fdp);
  842                 break;
  843 #ifdef CAPABILITIES
  844         case LA_SLOCKED:
  845                 FILEDESC_SUNLOCK(fdp);
  846                 break;
  847 #endif
  848         default:
  849                 FILEDESC_UNLOCK_ASSERT(fdp);
  850                 break;
  851         }
  852         if (fp != NULL)
  853                 fdrop(fp, td);
  854         return (error);
  855 }
  856 
  857 int
  858 poll_no_poll(int events)
  859 {
  860         /*
  861          * Return true for read/write.  If the user asked for something
  862          * special, return POLLNVAL, so that clients have a way of
  863          * determining reliably whether or not the extended
  864          * functionality is present without hard-coding knowledge
  865          * of specific filesystem implementations.
  866          */
  867         if (events & ~POLLSTANDARD)
  868                 return (POLLNVAL);
  869 
  870         return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
  871 }
  872 
  873 int
  874 sys_pselect(struct thread *td, struct pselect_args *uap)
  875 {
  876         struct timespec ts;
  877         struct timeval tv, *tvp;
  878         sigset_t set, *uset;
  879         int error;
  880 
  881         if (uap->ts != NULL) {
  882                 error = copyin(uap->ts, &ts, sizeof(ts));
  883                 if (error != 0)
  884                     return (error);
  885                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
  886                 tvp = &tv;
  887         } else
  888                 tvp = NULL;
  889         if (uap->sm != NULL) {
  890                 error = copyin(uap->sm, &set, sizeof(set));
  891                 if (error != 0)
  892                         return (error);
  893                 uset = &set;
  894         } else
  895                 uset = NULL;
  896         return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  897             uset, NFDBITS));
  898 }
  899 
  900 int
  901 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
  902     struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
  903 {
  904         int error;
  905 
  906         if (uset != NULL) {
  907                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
  908                     &td->td_oldsigmask, 0);
  909                 if (error != 0)
  910                         return (error);
  911                 td->td_pflags |= TDP_OLDMASK;
  912                 /*
  913                  * Make sure that ast() is called on return to
  914                  * usermode and TDP_OLDMASK is cleared, restoring old
  915                  * sigmask.
  916                  */
  917                 thread_lock(td);
  918                 td->td_flags |= TDF_ASTPENDING;
  919                 thread_unlock(td);
  920         }
  921         error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
  922         return (error);
  923 }
  924 
  925 #ifndef _SYS_SYSPROTO_H_
  926 struct select_args {
  927         int     nd;
  928         fd_set  *in, *ou, *ex;
  929         struct  timeval *tv;
  930 };
  931 #endif
  932 int
  933 sys_select(struct thread *td, struct select_args *uap)
  934 {
  935         struct timeval tv, *tvp;
  936         int error;
  937 
  938         if (uap->tv != NULL) {
  939                 error = copyin(uap->tv, &tv, sizeof(tv));
  940                 if (error)
  941                         return (error);
  942                 tvp = &tv;
  943         } else
  944                 tvp = NULL;
  945 
  946         return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  947             NFDBITS));
  948 }
  949 
  950 /*
  951  * In the unlikely case when user specified n greater then the last
  952  * open file descriptor, check that no bits are set after the last
  953  * valid fd.  We must return EBADF if any is set.
  954  *
  955  * There are applications that rely on the behaviour.
  956  *
  957  * nd is fd_lastfile + 1.
  958  */
  959 static int
  960 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits)
  961 {
  962         char *addr, *oaddr;
  963         int b, i, res;
  964         uint8_t bits;
  965 
  966         if (nd >= ndu || fd_in == NULL)
  967                 return (0);
  968 
  969         oaddr = NULL;
  970         bits = 0; /* silence gcc */
  971         for (i = nd; i < ndu; i++) {
  972                 b = i / NBBY;
  973 #if BYTE_ORDER == LITTLE_ENDIAN
  974                 addr = (char *)fd_in + b;
  975 #else
  976                 addr = (char *)fd_in;
  977                 if (abi_nfdbits == NFDBITS) {
  978                         addr += rounddown(b, sizeof(fd_mask)) +
  979                             sizeof(fd_mask) - 1 - b % sizeof(fd_mask);
  980                 } else {
  981                         addr += rounddown(b, sizeof(uint32_t)) +
  982                             sizeof(uint32_t) - 1 - b % sizeof(uint32_t);
  983                 }
  984 #endif
  985                 if (addr != oaddr) {
  986                         res = fubyte(addr);
  987                         if (res == -1)
  988                                 return (EFAULT);
  989                         oaddr = addr;
  990                         bits = res;
  991                 }
  992                 if ((bits & (1 << (i % NBBY))) != 0)
  993                         return (EBADF);
  994         }
  995         return (0);
  996 }
  997 
  998 int
  999 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
 1000     fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
 1001 {
 1002         struct filedesc *fdp;
 1003         /*
 1004          * The magic 2048 here is chosen to be just enough for FD_SETSIZE
 1005          * infds with the new FD_SETSIZE of 1024, and more than enough for
 1006          * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
 1007          * of 256.
 1008          */
 1009         fd_mask s_selbits[howmany(2048, NFDBITS)];
 1010         fd_mask *ibits[3], *obits[3], *selbits, *sbp;
 1011         struct timeval rtv;
 1012         sbintime_t asbt, precision, rsbt;
 1013         u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
 1014         int error, lf, ndu;
 1015 
 1016         if (nd < 0)
 1017                 return (EINVAL);
 1018         fdp = td->td_proc->p_fd;
 1019         ndu = nd;
 1020         lf = fdp->fd_lastfile;
 1021         if (nd > lf + 1)
 1022                 nd = lf + 1;
 1023 
 1024         error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits);
 1025         if (error != 0)
 1026                 return (error);
 1027         error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits);
 1028         if (error != 0)
 1029                 return (error);
 1030         error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits);
 1031         if (error != 0)
 1032                 return (error);
 1033 
 1034         /*
 1035          * Allocate just enough bits for the non-null fd_sets.  Use the
 1036          * preallocated auto buffer if possible.
 1037          */
 1038         nfdbits = roundup(nd, NFDBITS);
 1039         ncpbytes = nfdbits / NBBY;
 1040         ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
 1041         nbufbytes = 0;
 1042         if (fd_in != NULL)
 1043                 nbufbytes += 2 * ncpbytes;
 1044         if (fd_ou != NULL)
 1045                 nbufbytes += 2 * ncpbytes;
 1046         if (fd_ex != NULL)
 1047                 nbufbytes += 2 * ncpbytes;
 1048         if (nbufbytes <= sizeof s_selbits)
 1049                 selbits = &s_selbits[0];
 1050         else
 1051                 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
 1052 
 1053         /*
 1054          * Assign pointers into the bit buffers and fetch the input bits.
 1055          * Put the output buffers together so that they can be bzeroed
 1056          * together.
 1057          */
 1058         sbp = selbits;
 1059 #define getbits(name, x) \
 1060         do {                                                            \
 1061                 if (name == NULL) {                                     \
 1062                         ibits[x] = NULL;                                \
 1063                         obits[x] = NULL;                                \
 1064                 } else {                                                \
 1065                         ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp;   \
 1066                         obits[x] = sbp;                                 \
 1067                         sbp += ncpbytes / sizeof *sbp;                  \
 1068                         error = copyin(name, ibits[x], ncpubytes);      \
 1069                         if (error != 0)                                 \
 1070                                 goto done;                              \
 1071                         bzero((char *)ibits[x] + ncpubytes,             \
 1072                             ncpbytes - ncpubytes);                      \
 1073                 }                                                       \
 1074         } while (0)
 1075         getbits(fd_in, 0);
 1076         getbits(fd_ou, 1);
 1077         getbits(fd_ex, 2);
 1078 #undef  getbits
 1079 
 1080 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
 1081         /*
 1082          * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
 1083          * we are running under 32-bit emulation. This should be more
 1084          * generic.
 1085          */
 1086 #define swizzle_fdset(bits)                                             \
 1087         if (abi_nfdbits != NFDBITS && bits != NULL) {                   \
 1088                 int i;                                                  \
 1089                 for (i = 0; i < ncpbytes / sizeof *sbp; i++)            \
 1090                         bits[i] = (bits[i] >> 32) | (bits[i] << 32);    \
 1091         }
 1092 #else
 1093 #define swizzle_fdset(bits)
 1094 #endif
 1095 
 1096         /* Make sure the bit order makes it through an ABI transition */
 1097         swizzle_fdset(ibits[0]);
 1098         swizzle_fdset(ibits[1]);
 1099         swizzle_fdset(ibits[2]);
 1100         
 1101         if (nbufbytes != 0)
 1102                 bzero(selbits, nbufbytes / 2);
 1103 
 1104         precision = 0;
 1105         if (tvp != NULL) {
 1106                 rtv = *tvp;
 1107                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
 1108                     rtv.tv_usec >= 1000000) {
 1109                         error = EINVAL;
 1110                         goto done;
 1111                 }
 1112                 if (!timevalisset(&rtv))
 1113                         asbt = 0;
 1114                 else if (rtv.tv_sec <= INT32_MAX) {
 1115                         rsbt = tvtosbt(rtv);
 1116                         precision = rsbt;
 1117                         precision >>= tc_precexp;
 1118                         if (TIMESEL(&asbt, rsbt))
 1119                                 asbt += tc_tick_sbt;
 1120                         if (asbt <= SBT_MAX - rsbt)
 1121                                 asbt += rsbt;
 1122                         else
 1123                                 asbt = -1;
 1124                 } else
 1125                         asbt = -1;
 1126         } else
 1127                 asbt = -1;
 1128         seltdinit(td);
 1129         /* Iterate until the timeout expires or descriptors become ready. */
 1130         for (;;) {
 1131                 error = selscan(td, ibits, obits, nd);
 1132                 if (error || td->td_retval[0] != 0)
 1133                         break;
 1134                 error = seltdwait(td, asbt, precision);
 1135                 if (error)
 1136                         break;
 1137                 error = selrescan(td, ibits, obits);
 1138                 if (error || td->td_retval[0] != 0)
 1139                         break;
 1140         }
 1141         seltdclear(td);
 1142 
 1143 done:
 1144         /* select is not restarted after signals... */
 1145         if (error == ERESTART)
 1146                 error = EINTR;
 1147         if (error == EWOULDBLOCK)
 1148                 error = 0;
 1149 
 1150         /* swizzle bit order back, if necessary */
 1151         swizzle_fdset(obits[0]);
 1152         swizzle_fdset(obits[1]);
 1153         swizzle_fdset(obits[2]);
 1154 #undef swizzle_fdset
 1155 
 1156 #define putbits(name, x) \
 1157         if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
 1158                 error = error2;
 1159         if (error == 0) {
 1160                 int error2;
 1161 
 1162                 putbits(fd_in, 0);
 1163                 putbits(fd_ou, 1);
 1164                 putbits(fd_ex, 2);
 1165 #undef putbits
 1166         }
 1167         if (selbits != &s_selbits[0])
 1168                 free(selbits, M_SELECT);
 1169 
 1170         return (error);
 1171 }
 1172 /* 
 1173  * Convert a select bit set to poll flags.
 1174  *
 1175  * The backend always returns POLLHUP/POLLERR if appropriate and we
 1176  * return this as a set bit in any set.
 1177  */
 1178 static int select_flags[3] = {
 1179     POLLRDNORM | POLLHUP | POLLERR,
 1180     POLLWRNORM | POLLHUP | POLLERR,
 1181     POLLRDBAND | POLLERR
 1182 };
 1183 
 1184 /*
 1185  * Compute the fo_poll flags required for a fd given by the index and
 1186  * bit position in the fd_mask array.
 1187  */
 1188 static __inline int
 1189 selflags(fd_mask **ibits, int idx, fd_mask bit)
 1190 {
 1191         int flags;
 1192         int msk;
 1193 
 1194         flags = 0;
 1195         for (msk = 0; msk < 3; msk++) {
 1196                 if (ibits[msk] == NULL)
 1197                         continue;
 1198                 if ((ibits[msk][idx] & bit) == 0)
 1199                         continue;
 1200                 flags |= select_flags[msk];
 1201         }
 1202         return (flags);
 1203 }
 1204 
 1205 /*
 1206  * Set the appropriate output bits given a mask of fired events and the
 1207  * input bits originally requested.
 1208  */
 1209 static __inline int
 1210 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
 1211 {
 1212         int msk;
 1213         int n;
 1214 
 1215         n = 0;
 1216         for (msk = 0; msk < 3; msk++) {
 1217                 if ((events & select_flags[msk]) == 0)
 1218                         continue;
 1219                 if (ibits[msk] == NULL)
 1220                         continue;
 1221                 if ((ibits[msk][idx] & bit) == 0)
 1222                         continue;
 1223                 /*
 1224                  * XXX Check for a duplicate set.  This can occur because a
 1225                  * socket calls selrecord() twice for each poll() call
 1226                  * resulting in two selfds per real fd.  selrescan() will
 1227                  * call selsetbits twice as a result.
 1228                  */
 1229                 if ((obits[msk][idx] & bit) != 0)
 1230                         continue;
 1231                 obits[msk][idx] |= bit;
 1232                 n++;
 1233         }
 1234 
 1235         return (n);
 1236 }
 1237 
 1238 static __inline int
 1239 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp)
 1240 {
 1241         cap_rights_t rights;
 1242 
 1243         cap_rights_init(&rights, CAP_EVENT);
 1244 
 1245         return (fget_unlocked(fdp, fd, &rights, fpp, NULL));
 1246 }
 1247 
 1248 /*
 1249  * Traverse the list of fds attached to this thread's seltd and check for
 1250  * completion.
 1251  */
 1252 static int
 1253 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
 1254 {
 1255         struct filedesc *fdp;
 1256         struct selinfo *si;
 1257         struct seltd *stp;
 1258         struct selfd *sfp;
 1259         struct selfd *sfn;
 1260         struct file *fp;
 1261         fd_mask bit;
 1262         int fd, ev, n, idx;
 1263         int error;
 1264 
 1265         fdp = td->td_proc->p_fd;
 1266         stp = td->td_sel;
 1267         n = 0;
 1268         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1269                 fd = (int)(uintptr_t)sfp->sf_cookie;
 1270                 si = sfp->sf_si;
 1271                 selfdfree(stp, sfp);
 1272                 /* If the selinfo wasn't cleared the event didn't fire. */
 1273                 if (si != NULL)
 1274                         continue;
 1275                 error = getselfd_cap(fdp, fd, &fp);
 1276                 if (error)
 1277                         return (error);
 1278                 idx = fd / NFDBITS;
 1279                 bit = (fd_mask)1 << (fd % NFDBITS);
 1280                 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
 1281                 fdrop(fp, td);
 1282                 if (ev != 0)
 1283                         n += selsetbits(ibits, obits, idx, bit, ev);
 1284         }
 1285         stp->st_flags = 0;
 1286         td->td_retval[0] = n;
 1287         return (0);
 1288 }
 1289 
 1290 /*
 1291  * Perform the initial filedescriptor scan and register ourselves with
 1292  * each selinfo.
 1293  */
 1294 static int
 1295 selscan(td, ibits, obits, nfd)
 1296         struct thread *td;
 1297         fd_mask **ibits, **obits;
 1298         int nfd;
 1299 {
 1300         struct filedesc *fdp;
 1301         struct file *fp;
 1302         fd_mask bit;
 1303         int ev, flags, end, fd;
 1304         int n, idx;
 1305         int error;
 1306 
 1307         fdp = td->td_proc->p_fd;
 1308         n = 0;
 1309         for (idx = 0, fd = 0; fd < nfd; idx++) {
 1310                 end = imin(fd + NFDBITS, nfd);
 1311                 for (bit = 1; fd < end; bit <<= 1, fd++) {
 1312                         /* Compute the list of events we're interested in. */
 1313                         flags = selflags(ibits, idx, bit);
 1314                         if (flags == 0)
 1315                                 continue;
 1316                         error = getselfd_cap(fdp, fd, &fp);
 1317                         if (error)
 1318                                 return (error);
 1319                         selfdalloc(td, (void *)(uintptr_t)fd);
 1320                         ev = fo_poll(fp, flags, td->td_ucred, td);
 1321                         fdrop(fp, td);
 1322                         if (ev != 0)
 1323                                 n += selsetbits(ibits, obits, idx, bit, ev);
 1324                 }
 1325         }
 1326 
 1327         td->td_retval[0] = n;
 1328         return (0);
 1329 }
 1330 
 1331 int
 1332 sys_poll(struct thread *td, struct poll_args *uap)
 1333 {
 1334         struct timespec ts, *tsp;
 1335 
 1336         if (uap->timeout != INFTIM) {
 1337                 if (uap->timeout < 0)
 1338                         return (EINVAL);
 1339                 ts.tv_sec = uap->timeout / 1000;
 1340                 ts.tv_nsec = (uap->timeout % 1000) * 1000000;
 1341                 tsp = &ts;
 1342         } else
 1343                 tsp = NULL;
 1344 
 1345         return (kern_poll(td, uap->fds, uap->nfds, tsp, NULL));
 1346 }
 1347 
 1348 int
 1349 kern_poll(struct thread *td, struct pollfd *fds, u_int nfds,
 1350     struct timespec *tsp, sigset_t *uset)
 1351 {
 1352         struct pollfd *bits;
 1353         struct pollfd smallbits[32];
 1354         sbintime_t sbt, precision, tmp;
 1355         time_t over;
 1356         struct timespec ts;
 1357         int error;
 1358         size_t ni;
 1359 
 1360         precision = 0;
 1361         if (tsp != NULL) {
 1362                 if (tsp->tv_sec < 0)
 1363                         return (EINVAL);
 1364                 if (tsp->tv_nsec < 0 || tsp->tv_nsec >= 1000000000)
 1365                         return (EINVAL);
 1366                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
 1367                         sbt = 0;
 1368                 else {
 1369                         ts = *tsp;
 1370                         if (ts.tv_sec > INT32_MAX / 2) {
 1371                                 over = ts.tv_sec - INT32_MAX / 2;
 1372                                 ts.tv_sec -= over;
 1373                         } else
 1374                                 over = 0;
 1375                         tmp = tstosbt(ts);
 1376                         precision = tmp;
 1377                         precision >>= tc_precexp;
 1378                         if (TIMESEL(&sbt, tmp))
 1379                                 sbt += tc_tick_sbt;
 1380                         sbt += tmp;
 1381                 }
 1382         } else
 1383                 sbt = -1;
 1384 
 1385         if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 
 1386                 return (EINVAL);
 1387         ni = nfds * sizeof(struct pollfd);
 1388         if (ni > sizeof(smallbits))
 1389                 bits = malloc(ni, M_TEMP, M_WAITOK);
 1390         else
 1391                 bits = smallbits;
 1392         error = copyin(fds, bits, ni);
 1393         if (error)
 1394                 goto done;
 1395 
 1396         if (uset != NULL) {
 1397                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
 1398                     &td->td_oldsigmask, 0);
 1399                 if (error)
 1400                         goto done;
 1401                 td->td_pflags |= TDP_OLDMASK;
 1402                 /*
 1403                  * Make sure that ast() is called on return to
 1404                  * usermode and TDP_OLDMASK is cleared, restoring old
 1405                  * sigmask.
 1406                  */
 1407                 thread_lock(td);
 1408                 td->td_flags |= TDF_ASTPENDING;
 1409                 thread_unlock(td);
 1410         }
 1411 
 1412         seltdinit(td);
 1413         /* Iterate until the timeout expires or descriptors become ready. */
 1414         for (;;) {
 1415                 error = pollscan(td, bits, nfds);
 1416                 if (error || td->td_retval[0] != 0)
 1417                         break;
 1418                 error = seltdwait(td, sbt, precision);
 1419                 if (error)
 1420                         break;
 1421                 error = pollrescan(td);
 1422                 if (error || td->td_retval[0] != 0)
 1423                         break;
 1424         }
 1425         seltdclear(td);
 1426 
 1427 done:
 1428         /* poll is not restarted after signals... */
 1429         if (error == ERESTART)
 1430                 error = EINTR;
 1431         if (error == EWOULDBLOCK)
 1432                 error = 0;
 1433         if (error == 0) {
 1434                 error = pollout(td, bits, fds, nfds);
 1435                 if (error)
 1436                         goto out;
 1437         }
 1438 out:
 1439         if (ni > sizeof(smallbits))
 1440                 free(bits, M_TEMP);
 1441         return (error);
 1442 }
 1443 
 1444 int
 1445 sys_ppoll(struct thread *td, struct ppoll_args *uap)
 1446 {
 1447         struct timespec ts, *tsp;
 1448         sigset_t set, *ssp;
 1449         int error;
 1450 
 1451         if (uap->ts != NULL) {
 1452                 error = copyin(uap->ts, &ts, sizeof(ts));
 1453                 if (error)
 1454                         return (error);
 1455                 tsp = &ts;
 1456         } else
 1457                 tsp = NULL;
 1458         if (uap->set != NULL) {
 1459                 error = copyin(uap->set, &set, sizeof(set));
 1460                 if (error)
 1461                         return (error);
 1462                 ssp = &set;
 1463         } else
 1464                 ssp = NULL;
 1465         /*
 1466          * fds is still a pointer to user space. kern_poll() will
 1467          * take care of copyin that array to the kernel space.
 1468          */
 1469 
 1470         return (kern_poll(td, uap->fds, uap->nfds, tsp, ssp));
 1471 }
 1472 
 1473 static int
 1474 pollrescan(struct thread *td)
 1475 {
 1476         struct seltd *stp;
 1477         struct selfd *sfp;
 1478         struct selfd *sfn;
 1479         struct selinfo *si;
 1480         struct filedesc *fdp;
 1481         struct file *fp;
 1482         struct pollfd *fd;
 1483 #ifdef CAPABILITIES
 1484         cap_rights_t rights;
 1485 #endif
 1486         int n;
 1487 
 1488         n = 0;
 1489         fdp = td->td_proc->p_fd;
 1490         stp = td->td_sel;
 1491         FILEDESC_SLOCK(fdp);
 1492         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1493                 fd = (struct pollfd *)sfp->sf_cookie;
 1494                 si = sfp->sf_si;
 1495                 selfdfree(stp, sfp);
 1496                 /* If the selinfo wasn't cleared the event didn't fire. */
 1497                 if (si != NULL)
 1498                         continue;
 1499                 fp = fdp->fd_ofiles[fd->fd].fde_file;
 1500 #ifdef CAPABILITIES
 1501                 if (fp == NULL ||
 1502                     cap_check(cap_rights(fdp, fd->fd),
 1503                     cap_rights_init(&rights, CAP_EVENT)) != 0)
 1504 #else
 1505                 if (fp == NULL)
 1506 #endif
 1507                 {
 1508                         fd->revents = POLLNVAL;
 1509                         n++;
 1510                         continue;
 1511                 }
 1512 
 1513                 /*
 1514                  * Note: backend also returns POLLHUP and
 1515                  * POLLERR if appropriate.
 1516                  */
 1517                 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
 1518                 if (fd->revents != 0)
 1519                         n++;
 1520         }
 1521         FILEDESC_SUNLOCK(fdp);
 1522         stp->st_flags = 0;
 1523         td->td_retval[0] = n;
 1524         return (0);
 1525 }
 1526 
 1527 
 1528 static int
 1529 pollout(td, fds, ufds, nfd)
 1530         struct thread *td;
 1531         struct pollfd *fds;
 1532         struct pollfd *ufds;
 1533         u_int nfd;
 1534 {
 1535         int error = 0;
 1536         u_int i = 0;
 1537         u_int n = 0;
 1538 
 1539         for (i = 0; i < nfd; i++) {
 1540                 error = copyout(&fds->revents, &ufds->revents,
 1541                     sizeof(ufds->revents));
 1542                 if (error)
 1543                         return (error);
 1544                 if (fds->revents != 0)
 1545                         n++;
 1546                 fds++;
 1547                 ufds++;
 1548         }
 1549         td->td_retval[0] = n;
 1550         return (0);
 1551 }
 1552 
 1553 static int
 1554 pollscan(td, fds, nfd)
 1555         struct thread *td;
 1556         struct pollfd *fds;
 1557         u_int nfd;
 1558 {
 1559         struct filedesc *fdp = td->td_proc->p_fd;
 1560         struct file *fp;
 1561 #ifdef CAPABILITIES
 1562         cap_rights_t rights;
 1563 #endif
 1564         int i, n = 0;
 1565 
 1566         FILEDESC_SLOCK(fdp);
 1567         for (i = 0; i < nfd; i++, fds++) {
 1568                 if (fds->fd > fdp->fd_lastfile) {
 1569                         fds->revents = POLLNVAL;
 1570                         n++;
 1571                 } else if (fds->fd < 0) {
 1572                         fds->revents = 0;
 1573                 } else {
 1574                         fp = fdp->fd_ofiles[fds->fd].fde_file;
 1575 #ifdef CAPABILITIES
 1576                         if (fp == NULL ||
 1577                             cap_check(cap_rights(fdp, fds->fd),
 1578                             cap_rights_init(&rights, CAP_EVENT)) != 0)
 1579 #else
 1580                         if (fp == NULL)
 1581 #endif
 1582                         {
 1583                                 fds->revents = POLLNVAL;
 1584                                 n++;
 1585                         } else {
 1586                                 /*
 1587                                  * Note: backend also returns POLLHUP and
 1588                                  * POLLERR if appropriate.
 1589                                  */
 1590                                 selfdalloc(td, fds);
 1591                                 fds->revents = fo_poll(fp, fds->events,
 1592                                     td->td_ucred, td);
 1593                                 /*
 1594                                  * POSIX requires POLLOUT to be never
 1595                                  * set simultaneously with POLLHUP.
 1596                                  */
 1597                                 if ((fds->revents & POLLHUP) != 0)
 1598                                         fds->revents &= ~POLLOUT;
 1599 
 1600                                 if (fds->revents != 0)
 1601                                         n++;
 1602                         }
 1603                 }
 1604         }
 1605         FILEDESC_SUNLOCK(fdp);
 1606         td->td_retval[0] = n;
 1607         return (0);
 1608 }
 1609 
 1610 /*
 1611  * OpenBSD poll system call.
 1612  *
 1613  * XXX this isn't quite a true representation..  OpenBSD uses select ops.
 1614  */
 1615 #ifndef _SYS_SYSPROTO_H_
 1616 struct openbsd_poll_args {
 1617         struct pollfd *fds;
 1618         u_int   nfds;
 1619         int     timeout;
 1620 };
 1621 #endif
 1622 int
 1623 sys_openbsd_poll(td, uap)
 1624         register struct thread *td;
 1625         register struct openbsd_poll_args *uap;
 1626 {
 1627         return (sys_poll(td, (struct poll_args *)uap));
 1628 }
 1629 
 1630 /*
 1631  * XXX This was created specifically to support netncp and netsmb.  This
 1632  * allows the caller to specify a socket to wait for events on.  It returns
 1633  * 0 if any events matched and an error otherwise.  There is no way to
 1634  * determine which events fired.
 1635  */
 1636 int
 1637 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
 1638 {
 1639         struct timeval rtv;
 1640         sbintime_t asbt, precision, rsbt;
 1641         int error;
 1642 
 1643         precision = 0;  /* stupid gcc! */
 1644         if (tvp != NULL) {
 1645                 rtv = *tvp;
 1646                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 || 
 1647                     rtv.tv_usec >= 1000000)
 1648                         return (EINVAL);
 1649                 if (!timevalisset(&rtv))
 1650                         asbt = 0;
 1651                 else if (rtv.tv_sec <= INT32_MAX) {
 1652                         rsbt = tvtosbt(rtv);
 1653                         precision = rsbt;
 1654                         precision >>= tc_precexp;
 1655                         if (TIMESEL(&asbt, rsbt))
 1656                                 asbt += tc_tick_sbt;
 1657                         if (asbt <= SBT_MAX - rsbt)
 1658                                 asbt += rsbt;
 1659                         else
 1660                                 asbt = -1;
 1661                 } else
 1662                         asbt = -1;
 1663         } else
 1664                 asbt = -1;
 1665         seltdinit(td);
 1666         /*
 1667          * Iterate until the timeout expires or the socket becomes ready.
 1668          */
 1669         for (;;) {
 1670                 selfdalloc(td, NULL);
 1671                 error = sopoll(so, events, NULL, td);
 1672                 /* error here is actually the ready events. */
 1673                 if (error)
 1674                         return (0);
 1675                 error = seltdwait(td, asbt, precision);
 1676                 if (error)
 1677                         break;
 1678         }
 1679         seltdclear(td);
 1680         /* XXX Duplicates ncp/smb behavior. */
 1681         if (error == ERESTART)
 1682                 error = 0;
 1683         return (error);
 1684 }
 1685 
 1686 /*
 1687  * Preallocate two selfds associated with 'cookie'.  Some fo_poll routines
 1688  * have two select sets, one for read and another for write.
 1689  */
 1690 static void
 1691 selfdalloc(struct thread *td, void *cookie)
 1692 {
 1693         struct seltd *stp;
 1694 
 1695         stp = td->td_sel;
 1696         if (stp->st_free1 == NULL)
 1697                 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1698         stp->st_free1->sf_td = stp;
 1699         stp->st_free1->sf_cookie = cookie;
 1700         if (stp->st_free2 == NULL)
 1701                 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1702         stp->st_free2->sf_td = stp;
 1703         stp->st_free2->sf_cookie = cookie;
 1704 }
 1705 
 1706 static void
 1707 selfdfree(struct seltd *stp, struct selfd *sfp)
 1708 {
 1709         STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
 1710         if (sfp->sf_si != NULL) {
 1711                 mtx_lock(sfp->sf_mtx);
 1712                 if (sfp->sf_si != NULL) {
 1713                         TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
 1714                         refcount_release(&sfp->sf_refs);
 1715                 }
 1716                 mtx_unlock(sfp->sf_mtx);
 1717         }
 1718         if (refcount_release(&sfp->sf_refs))
 1719                 uma_zfree(selfd_zone, sfp);
 1720 }
 1721 
 1722 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */
 1723 void
 1724 seldrain(sip)
 1725         struct selinfo *sip;
 1726 {
 1727 
 1728         /*
 1729          * This feature is already provided by doselwakeup(), thus it is
 1730          * enough to go for it.
 1731          * Eventually, the context, should take care to avoid races
 1732          * between thread calling select()/poll() and file descriptor
 1733          * detaching, but, again, the races are just the same as
 1734          * selwakeup().
 1735          */
 1736         doselwakeup(sip, -1);
 1737 }
 1738 
 1739 /*
 1740  * Record a select request.
 1741  */
 1742 void
 1743 selrecord(selector, sip)
 1744         struct thread *selector;
 1745         struct selinfo *sip;
 1746 {
 1747         struct selfd *sfp;
 1748         struct seltd *stp;
 1749         struct mtx *mtxp;
 1750 
 1751         stp = selector->td_sel;
 1752         /*
 1753          * Don't record when doing a rescan.
 1754          */
 1755         if (stp->st_flags & SELTD_RESCAN)
 1756                 return;
 1757         /*
 1758          * Grab one of the preallocated descriptors.
 1759          */
 1760         sfp = NULL;
 1761         if ((sfp = stp->st_free1) != NULL)
 1762                 stp->st_free1 = NULL;
 1763         else if ((sfp = stp->st_free2) != NULL)
 1764                 stp->st_free2 = NULL;
 1765         else
 1766                 panic("selrecord: No free selfd on selq");
 1767         mtxp = sip->si_mtx;
 1768         if (mtxp == NULL)
 1769                 mtxp = mtx_pool_find(mtxpool_select, sip);
 1770         /*
 1771          * Initialize the sfp and queue it in the thread.
 1772          */
 1773         sfp->sf_si = sip;
 1774         sfp->sf_mtx = mtxp;
 1775         refcount_init(&sfp->sf_refs, 2);
 1776         STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
 1777         /*
 1778          * Now that we've locked the sip, check for initialization.
 1779          */
 1780         mtx_lock(mtxp);
 1781         if (sip->si_mtx == NULL) {
 1782                 sip->si_mtx = mtxp;
 1783                 TAILQ_INIT(&sip->si_tdlist);
 1784         }
 1785         /*
 1786          * Add this thread to the list of selfds listening on this selinfo.
 1787          */
 1788         TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
 1789         mtx_unlock(sip->si_mtx);
 1790 }
 1791 
 1792 /* Wake up a selecting thread. */
 1793 void
 1794 selwakeup(sip)
 1795         struct selinfo *sip;
 1796 {
 1797         doselwakeup(sip, -1);
 1798 }
 1799 
 1800 /* Wake up a selecting thread, and set its priority. */
 1801 void
 1802 selwakeuppri(sip, pri)
 1803         struct selinfo *sip;
 1804         int pri;
 1805 {
 1806         doselwakeup(sip, pri);
 1807 }
 1808 
 1809 /*
 1810  * Do a wakeup when a selectable event occurs.
 1811  */
 1812 static void
 1813 doselwakeup(sip, pri)
 1814         struct selinfo *sip;
 1815         int pri;
 1816 {
 1817         struct selfd *sfp;
 1818         struct selfd *sfn;
 1819         struct seltd *stp;
 1820 
 1821         /* If it's not initialized there can't be any waiters. */
 1822         if (sip->si_mtx == NULL)
 1823                 return;
 1824         /*
 1825          * Locking the selinfo locks all selfds associated with it.
 1826          */
 1827         mtx_lock(sip->si_mtx);
 1828         TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
 1829                 /*
 1830                  * Once we remove this sfp from the list and clear the
 1831                  * sf_si seltdclear will know to ignore this si.
 1832                  */
 1833                 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
 1834                 sfp->sf_si = NULL;
 1835                 stp = sfp->sf_td;
 1836                 mtx_lock(&stp->st_mtx);
 1837                 stp->st_flags |= SELTD_PENDING;
 1838                 cv_broadcastpri(&stp->st_wait, pri);
 1839                 mtx_unlock(&stp->st_mtx);
 1840                 if (refcount_release(&sfp->sf_refs))
 1841                         uma_zfree(selfd_zone, sfp);
 1842         }
 1843         mtx_unlock(sip->si_mtx);
 1844 }
 1845 
 1846 static void
 1847 seltdinit(struct thread *td)
 1848 {
 1849         struct seltd *stp;
 1850 
 1851         if ((stp = td->td_sel) != NULL)
 1852                 goto out;
 1853         td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
 1854         mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
 1855         cv_init(&stp->st_wait, "select");
 1856 out:
 1857         stp->st_flags = 0;
 1858         STAILQ_INIT(&stp->st_selq);
 1859 }
 1860 
 1861 static int
 1862 seltdwait(struct thread *td, sbintime_t sbt, sbintime_t precision)
 1863 {
 1864         struct seltd *stp;
 1865         int error;
 1866 
 1867         stp = td->td_sel;
 1868         /*
 1869          * An event of interest may occur while we do not hold the seltd
 1870          * locked so check the pending flag before we sleep.
 1871          */
 1872         mtx_lock(&stp->st_mtx);
 1873         /*
 1874          * Any further calls to selrecord will be a rescan.
 1875          */
 1876         stp->st_flags |= SELTD_RESCAN;
 1877         if (stp->st_flags & SELTD_PENDING) {
 1878                 mtx_unlock(&stp->st_mtx);
 1879                 return (0);
 1880         }
 1881         if (sbt == 0)
 1882                 error = EWOULDBLOCK;
 1883         else if (sbt != -1)
 1884                 error = cv_timedwait_sig_sbt(&stp->st_wait, &stp->st_mtx,
 1885                     sbt, precision, C_ABSOLUTE);
 1886         else
 1887                 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
 1888         mtx_unlock(&stp->st_mtx);
 1889 
 1890         return (error);
 1891 }
 1892 
 1893 void
 1894 seltdfini(struct thread *td)
 1895 {
 1896         struct seltd *stp;
 1897 
 1898         stp = td->td_sel;
 1899         if (stp == NULL)
 1900                 return;
 1901         if (stp->st_free1)
 1902                 uma_zfree(selfd_zone, stp->st_free1);
 1903         if (stp->st_free2)
 1904                 uma_zfree(selfd_zone, stp->st_free2);
 1905         td->td_sel = NULL;
 1906         cv_destroy(&stp->st_wait);
 1907         mtx_destroy(&stp->st_mtx);
 1908         free(stp, M_SELECT);
 1909 }
 1910 
 1911 /*
 1912  * Remove the references to the thread from all of the objects we were
 1913  * polling.
 1914  */
 1915 static void
 1916 seltdclear(struct thread *td)
 1917 {
 1918         struct seltd *stp;
 1919         struct selfd *sfp;
 1920         struct selfd *sfn;
 1921 
 1922         stp = td->td_sel;
 1923         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
 1924                 selfdfree(stp, sfp);
 1925         stp->st_flags = 0;
 1926 }
 1927 
 1928 static void selectinit(void *);
 1929 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
 1930 static void
 1931 selectinit(void *dummy __unused)
 1932 {
 1933 
 1934         selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
 1935             NULL, NULL, UMA_ALIGN_PTR, 0);
 1936         mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
 1937 }
 1938 
 1939 /*
 1940  * Set up a syscall return value that follows the convention specified for
 1941  * posix_* functions.
 1942  */
 1943 int
 1944 kern_posix_error(struct thread *td, int error)
 1945 {
 1946 
 1947         if (error <= 0)
 1948                 return (error);
 1949         td->td_errno = error;
 1950         td->td_pflags |= TDP_NERRNO;
 1951         td->td_retval[0] = error;
 1952         return (0);
 1953 }

Cache object: a227e17b3b952da4224e2f9c3afee477


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