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

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1989, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)sys_generic.c       8.5 (Berkeley) 1/21/94
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD: releng/11.2/sys/kern/sys_generic.c 331722 2018-03-29 02:50:57Z eadler $");
   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         u_long com;
  692         int arg, error;
  693         u_int size;
  694         caddr_t data;
  695 
  696         if (uap->com > 0xffffffff) {
  697                 printf(
  698                     "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
  699                     td->td_proc->p_pid, td->td_name, uap->com);
  700                 uap->com &= 0xffffffff;
  701         }
  702         com = uap->com;
  703 
  704         /*
  705          * Interpret high order word to find amount of data to be
  706          * copied to/from the user's address space.
  707          */
  708         size = IOCPARM_LEN(com);
  709         if ((size > IOCPARM_MAX) ||
  710             ((com & (IOC_VOID  | IOC_IN | IOC_OUT)) == 0) ||
  711 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
  712             ((com & IOC_OUT) && size == 0) ||
  713 #else
  714             ((com & (IOC_IN | IOC_OUT)) && size == 0) ||
  715 #endif
  716             ((com & IOC_VOID) && size > 0 && size != sizeof(int)))
  717                 return (ENOTTY);
  718 
  719         if (size > 0) {
  720                 if (com & IOC_VOID) {
  721                         /* Integer argument. */
  722                         arg = (intptr_t)uap->data;
  723                         data = (void *)&arg;
  724                         size = 0;
  725                 } else {
  726                         if (size > SYS_IOCTL_SMALL_SIZE)
  727                                 data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
  728                         else
  729                                 data = smalldata;
  730                 }
  731         } else
  732                 data = (void *)&uap->data;
  733         if (com & IOC_IN) {
  734                 error = copyin(uap->data, data, (u_int)size);
  735                 if (error != 0)
  736                         goto out;
  737         } else if (com & IOC_OUT) {
  738                 /*
  739                  * Zero the buffer so the user always
  740                  * gets back something deterministic.
  741                  */
  742                 bzero(data, size);
  743         }
  744 
  745         error = kern_ioctl(td, uap->fd, com, data);
  746 
  747         if (error == 0 && (com & IOC_OUT))
  748                 error = copyout(data, uap->data, (u_int)size);
  749 
  750 out:
  751         if (size > SYS_IOCTL_SMALL_SIZE)
  752                 free(data, M_IOCTLOPS);
  753         return (error);
  754 }
  755 
  756 int
  757 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
  758 {
  759         struct file *fp;
  760         struct filedesc *fdp;
  761 #ifndef CAPABILITIES
  762         cap_rights_t rights;
  763 #endif
  764         int error, tmp, locked;
  765 
  766         AUDIT_ARG_FD(fd);
  767         AUDIT_ARG_CMD(com);
  768 
  769         fdp = td->td_proc->p_fd;
  770 
  771         switch (com) {
  772         case FIONCLEX:
  773         case FIOCLEX:
  774                 FILEDESC_XLOCK(fdp);
  775                 locked = LA_XLOCKED;
  776                 break;
  777         default:
  778 #ifdef CAPABILITIES
  779                 FILEDESC_SLOCK(fdp);
  780                 locked = LA_SLOCKED;
  781 #else
  782                 locked = LA_UNLOCKED;
  783 #endif
  784                 break;
  785         }
  786 
  787 #ifdef CAPABILITIES
  788         if ((fp = fget_locked(fdp, fd)) == NULL) {
  789                 error = EBADF;
  790                 goto out;
  791         }
  792         if ((error = cap_ioctl_check(fdp, fd, com)) != 0) {
  793                 fp = NULL;      /* fhold() was not called yet */
  794                 goto out;
  795         }
  796         fhold(fp);
  797         if (locked == LA_SLOCKED) {
  798                 FILEDESC_SUNLOCK(fdp);
  799                 locked = LA_UNLOCKED;
  800         }
  801 #else
  802         error = fget(td, fd, cap_rights_init(&rights, CAP_IOCTL), &fp);
  803         if (error != 0) {
  804                 fp = NULL;
  805                 goto out;
  806         }
  807 #endif
  808         if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
  809                 error = EBADF;
  810                 goto out;
  811         }
  812 
  813         switch (com) {
  814         case FIONCLEX:
  815                 fdp->fd_ofiles[fd].fde_flags &= ~UF_EXCLOSE;
  816                 goto out;
  817         case FIOCLEX:
  818                 fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE;
  819                 goto out;
  820         case FIONBIO:
  821                 if ((tmp = *(int *)data))
  822                         atomic_set_int(&fp->f_flag, FNONBLOCK);
  823                 else
  824                         atomic_clear_int(&fp->f_flag, FNONBLOCK);
  825                 data = (void *)&tmp;
  826                 break;
  827         case FIOASYNC:
  828                 if ((tmp = *(int *)data))
  829                         atomic_set_int(&fp->f_flag, FASYNC);
  830                 else
  831                         atomic_clear_int(&fp->f_flag, FASYNC);
  832                 data = (void *)&tmp;
  833                 break;
  834         }
  835 
  836         error = fo_ioctl(fp, com, data, td->td_ucred, td);
  837 out:
  838         switch (locked) {
  839         case LA_XLOCKED:
  840                 FILEDESC_XUNLOCK(fdp);
  841                 break;
  842 #ifdef CAPABILITIES
  843         case LA_SLOCKED:
  844                 FILEDESC_SUNLOCK(fdp);
  845                 break;
  846 #endif
  847         default:
  848                 FILEDESC_UNLOCK_ASSERT(fdp);
  849                 break;
  850         }
  851         if (fp != NULL)
  852                 fdrop(fp, td);
  853         return (error);
  854 }
  855 
  856 int
  857 poll_no_poll(int events)
  858 {
  859         /*
  860          * Return true for read/write.  If the user asked for something
  861          * special, return POLLNVAL, so that clients have a way of
  862          * determining reliably whether or not the extended
  863          * functionality is present without hard-coding knowledge
  864          * of specific filesystem implementations.
  865          */
  866         if (events & ~POLLSTANDARD)
  867                 return (POLLNVAL);
  868 
  869         return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
  870 }
  871 
  872 int
  873 sys_pselect(struct thread *td, struct pselect_args *uap)
  874 {
  875         struct timespec ts;
  876         struct timeval tv, *tvp;
  877         sigset_t set, *uset;
  878         int error;
  879 
  880         if (uap->ts != NULL) {
  881                 error = copyin(uap->ts, &ts, sizeof(ts));
  882                 if (error != 0)
  883                     return (error);
  884                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
  885                 tvp = &tv;
  886         } else
  887                 tvp = NULL;
  888         if (uap->sm != NULL) {
  889                 error = copyin(uap->sm, &set, sizeof(set));
  890                 if (error != 0)
  891                         return (error);
  892                 uset = &set;
  893         } else
  894                 uset = NULL;
  895         return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  896             uset, NFDBITS));
  897 }
  898 
  899 int
  900 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
  901     struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
  902 {
  903         int error;
  904 
  905         if (uset != NULL) {
  906                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
  907                     &td->td_oldsigmask, 0);
  908                 if (error != 0)
  909                         return (error);
  910                 td->td_pflags |= TDP_OLDMASK;
  911                 /*
  912                  * Make sure that ast() is called on return to
  913                  * usermode and TDP_OLDMASK is cleared, restoring old
  914                  * sigmask.
  915                  */
  916                 thread_lock(td);
  917                 td->td_flags |= TDF_ASTPENDING;
  918                 thread_unlock(td);
  919         }
  920         error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
  921         return (error);
  922 }
  923 
  924 #ifndef _SYS_SYSPROTO_H_
  925 struct select_args {
  926         int     nd;
  927         fd_set  *in, *ou, *ex;
  928         struct  timeval *tv;
  929 };
  930 #endif
  931 int
  932 sys_select(struct thread *td, struct select_args *uap)
  933 {
  934         struct timeval tv, *tvp;
  935         int error;
  936 
  937         if (uap->tv != NULL) {
  938                 error = copyin(uap->tv, &tv, sizeof(tv));
  939                 if (error)
  940                         return (error);
  941                 tvp = &tv;
  942         } else
  943                 tvp = NULL;
  944 
  945         return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  946             NFDBITS));
  947 }
  948 
  949 /*
  950  * In the unlikely case when user specified n greater then the last
  951  * open file descriptor, check that no bits are set after the last
  952  * valid fd.  We must return EBADF if any is set.
  953  *
  954  * There are applications that rely on the behaviour.
  955  *
  956  * nd is fd_lastfile + 1.
  957  */
  958 static int
  959 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits)
  960 {
  961         char *addr, *oaddr;
  962         int b, i, res;
  963         uint8_t bits;
  964 
  965         if (nd >= ndu || fd_in == NULL)
  966                 return (0);
  967 
  968         oaddr = NULL;
  969         bits = 0; /* silence gcc */
  970         for (i = nd; i < ndu; i++) {
  971                 b = i / NBBY;
  972 #if BYTE_ORDER == LITTLE_ENDIAN
  973                 addr = (char *)fd_in + b;
  974 #else
  975                 addr = (char *)fd_in;
  976                 if (abi_nfdbits == NFDBITS) {
  977                         addr += rounddown(b, sizeof(fd_mask)) +
  978                             sizeof(fd_mask) - 1 - b % sizeof(fd_mask);
  979                 } else {
  980                         addr += rounddown(b, sizeof(uint32_t)) +
  981                             sizeof(uint32_t) - 1 - b % sizeof(uint32_t);
  982                 }
  983 #endif
  984                 if (addr != oaddr) {
  985                         res = fubyte(addr);
  986                         if (res == -1)
  987                                 return (EFAULT);
  988                         oaddr = addr;
  989                         bits = res;
  990                 }
  991                 if ((bits & (1 << (i % NBBY))) != 0)
  992                         return (EBADF);
  993         }
  994         return (0);
  995 }
  996 
  997 int
  998 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
  999     fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
 1000 {
 1001         struct filedesc *fdp;
 1002         /*
 1003          * The magic 2048 here is chosen to be just enough for FD_SETSIZE
 1004          * infds with the new FD_SETSIZE of 1024, and more than enough for
 1005          * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
 1006          * of 256.
 1007          */
 1008         fd_mask s_selbits[howmany(2048, NFDBITS)];
 1009         fd_mask *ibits[3], *obits[3], *selbits, *sbp;
 1010         struct timeval rtv;
 1011         sbintime_t asbt, precision, rsbt;
 1012         u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
 1013         int error, lf, ndu;
 1014 
 1015         if (nd < 0)
 1016                 return (EINVAL);
 1017         fdp = td->td_proc->p_fd;
 1018         ndu = nd;
 1019         lf = fdp->fd_lastfile;
 1020         if (nd > lf + 1)
 1021                 nd = lf + 1;
 1022 
 1023         error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits);
 1024         if (error != 0)
 1025                 return (error);
 1026         error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits);
 1027         if (error != 0)
 1028                 return (error);
 1029         error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits);
 1030         if (error != 0)
 1031                 return (error);
 1032 
 1033         /*
 1034          * Allocate just enough bits for the non-null fd_sets.  Use the
 1035          * preallocated auto buffer if possible.
 1036          */
 1037         nfdbits = roundup(nd, NFDBITS);
 1038         ncpbytes = nfdbits / NBBY;
 1039         ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
 1040         nbufbytes = 0;
 1041         if (fd_in != NULL)
 1042                 nbufbytes += 2 * ncpbytes;
 1043         if (fd_ou != NULL)
 1044                 nbufbytes += 2 * ncpbytes;
 1045         if (fd_ex != NULL)
 1046                 nbufbytes += 2 * ncpbytes;
 1047         if (nbufbytes <= sizeof s_selbits)
 1048                 selbits = &s_selbits[0];
 1049         else
 1050                 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
 1051 
 1052         /*
 1053          * Assign pointers into the bit buffers and fetch the input bits.
 1054          * Put the output buffers together so that they can be bzeroed
 1055          * together.
 1056          */
 1057         sbp = selbits;
 1058 #define getbits(name, x) \
 1059         do {                                                            \
 1060                 if (name == NULL) {                                     \
 1061                         ibits[x] = NULL;                                \
 1062                         obits[x] = NULL;                                \
 1063                 } else {                                                \
 1064                         ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp;   \
 1065                         obits[x] = sbp;                                 \
 1066                         sbp += ncpbytes / sizeof *sbp;                  \
 1067                         error = copyin(name, ibits[x], ncpubytes);      \
 1068                         if (error != 0)                                 \
 1069                                 goto done;                              \
 1070                         bzero((char *)ibits[x] + ncpubytes,             \
 1071                             ncpbytes - ncpubytes);                      \
 1072                 }                                                       \
 1073         } while (0)
 1074         getbits(fd_in, 0);
 1075         getbits(fd_ou, 1);
 1076         getbits(fd_ex, 2);
 1077 #undef  getbits
 1078 
 1079 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
 1080         /*
 1081          * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
 1082          * we are running under 32-bit emulation. This should be more
 1083          * generic.
 1084          */
 1085 #define swizzle_fdset(bits)                                             \
 1086         if (abi_nfdbits != NFDBITS && bits != NULL) {                   \
 1087                 int i;                                                  \
 1088                 for (i = 0; i < ncpbytes / sizeof *sbp; i++)            \
 1089                         bits[i] = (bits[i] >> 32) | (bits[i] << 32);    \
 1090         }
 1091 #else
 1092 #define swizzle_fdset(bits)
 1093 #endif
 1094 
 1095         /* Make sure the bit order makes it through an ABI transition */
 1096         swizzle_fdset(ibits[0]);
 1097         swizzle_fdset(ibits[1]);
 1098         swizzle_fdset(ibits[2]);
 1099         
 1100         if (nbufbytes != 0)
 1101                 bzero(selbits, nbufbytes / 2);
 1102 
 1103         precision = 0;
 1104         if (tvp != NULL) {
 1105                 rtv = *tvp;
 1106                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
 1107                     rtv.tv_usec >= 1000000) {
 1108                         error = EINVAL;
 1109                         goto done;
 1110                 }
 1111                 if (!timevalisset(&rtv))
 1112                         asbt = 0;
 1113                 else if (rtv.tv_sec <= INT32_MAX) {
 1114                         rsbt = tvtosbt(rtv);
 1115                         precision = rsbt;
 1116                         precision >>= tc_precexp;
 1117                         if (TIMESEL(&asbt, rsbt))
 1118                                 asbt += tc_tick_sbt;
 1119                         if (asbt <= SBT_MAX - rsbt)
 1120                                 asbt += rsbt;
 1121                         else
 1122                                 asbt = -1;
 1123                 } else
 1124                         asbt = -1;
 1125         } else
 1126                 asbt = -1;
 1127         seltdinit(td);
 1128         /* Iterate until the timeout expires or descriptors become ready. */
 1129         for (;;) {
 1130                 error = selscan(td, ibits, obits, nd);
 1131                 if (error || td->td_retval[0] != 0)
 1132                         break;
 1133                 error = seltdwait(td, asbt, precision);
 1134                 if (error)
 1135                         break;
 1136                 error = selrescan(td, ibits, obits);
 1137                 if (error || td->td_retval[0] != 0)
 1138                         break;
 1139         }
 1140         seltdclear(td);
 1141 
 1142 done:
 1143         /* select is not restarted after signals... */
 1144         if (error == ERESTART)
 1145                 error = EINTR;
 1146         if (error == EWOULDBLOCK)
 1147                 error = 0;
 1148 
 1149         /* swizzle bit order back, if necessary */
 1150         swizzle_fdset(obits[0]);
 1151         swizzle_fdset(obits[1]);
 1152         swizzle_fdset(obits[2]);
 1153 #undef swizzle_fdset
 1154 
 1155 #define putbits(name, x) \
 1156         if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
 1157                 error = error2;
 1158         if (error == 0) {
 1159                 int error2;
 1160 
 1161                 putbits(fd_in, 0);
 1162                 putbits(fd_ou, 1);
 1163                 putbits(fd_ex, 2);
 1164 #undef putbits
 1165         }
 1166         if (selbits != &s_selbits[0])
 1167                 free(selbits, M_SELECT);
 1168 
 1169         return (error);
 1170 }
 1171 /* 
 1172  * Convert a select bit set to poll flags.
 1173  *
 1174  * The backend always returns POLLHUP/POLLERR if appropriate and we
 1175  * return this as a set bit in any set.
 1176  */
 1177 static int select_flags[3] = {
 1178     POLLRDNORM | POLLHUP | POLLERR,
 1179     POLLWRNORM | POLLHUP | POLLERR,
 1180     POLLRDBAND | POLLERR
 1181 };
 1182 
 1183 /*
 1184  * Compute the fo_poll flags required for a fd given by the index and
 1185  * bit position in the fd_mask array.
 1186  */
 1187 static __inline int
 1188 selflags(fd_mask **ibits, int idx, fd_mask bit)
 1189 {
 1190         int flags;
 1191         int msk;
 1192 
 1193         flags = 0;
 1194         for (msk = 0; msk < 3; msk++) {
 1195                 if (ibits[msk] == NULL)
 1196                         continue;
 1197                 if ((ibits[msk][idx] & bit) == 0)
 1198                         continue;
 1199                 flags |= select_flags[msk];
 1200         }
 1201         return (flags);
 1202 }
 1203 
 1204 /*
 1205  * Set the appropriate output bits given a mask of fired events and the
 1206  * input bits originally requested.
 1207  */
 1208 static __inline int
 1209 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
 1210 {
 1211         int msk;
 1212         int n;
 1213 
 1214         n = 0;
 1215         for (msk = 0; msk < 3; msk++) {
 1216                 if ((events & select_flags[msk]) == 0)
 1217                         continue;
 1218                 if (ibits[msk] == NULL)
 1219                         continue;
 1220                 if ((ibits[msk][idx] & bit) == 0)
 1221                         continue;
 1222                 /*
 1223                  * XXX Check for a duplicate set.  This can occur because a
 1224                  * socket calls selrecord() twice for each poll() call
 1225                  * resulting in two selfds per real fd.  selrescan() will
 1226                  * call selsetbits twice as a result.
 1227                  */
 1228                 if ((obits[msk][idx] & bit) != 0)
 1229                         continue;
 1230                 obits[msk][idx] |= bit;
 1231                 n++;
 1232         }
 1233 
 1234         return (n);
 1235 }
 1236 
 1237 static __inline int
 1238 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp)
 1239 {
 1240         cap_rights_t rights;
 1241 
 1242         cap_rights_init(&rights, CAP_EVENT);
 1243 
 1244         return (fget_unlocked(fdp, fd, &rights, fpp, NULL));
 1245 }
 1246 
 1247 /*
 1248  * Traverse the list of fds attached to this thread's seltd and check for
 1249  * completion.
 1250  */
 1251 static int
 1252 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
 1253 {
 1254         struct filedesc *fdp;
 1255         struct selinfo *si;
 1256         struct seltd *stp;
 1257         struct selfd *sfp;
 1258         struct selfd *sfn;
 1259         struct file *fp;
 1260         fd_mask bit;
 1261         int fd, ev, n, idx;
 1262         int error;
 1263 
 1264         fdp = td->td_proc->p_fd;
 1265         stp = td->td_sel;
 1266         n = 0;
 1267         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1268                 fd = (int)(uintptr_t)sfp->sf_cookie;
 1269                 si = sfp->sf_si;
 1270                 selfdfree(stp, sfp);
 1271                 /* If the selinfo wasn't cleared the event didn't fire. */
 1272                 if (si != NULL)
 1273                         continue;
 1274                 error = getselfd_cap(fdp, fd, &fp);
 1275                 if (error)
 1276                         return (error);
 1277                 idx = fd / NFDBITS;
 1278                 bit = (fd_mask)1 << (fd % NFDBITS);
 1279                 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
 1280                 fdrop(fp, td);
 1281                 if (ev != 0)
 1282                         n += selsetbits(ibits, obits, idx, bit, ev);
 1283         }
 1284         stp->st_flags = 0;
 1285         td->td_retval[0] = n;
 1286         return (0);
 1287 }
 1288 
 1289 /*
 1290  * Perform the initial filedescriptor scan and register ourselves with
 1291  * each selinfo.
 1292  */
 1293 static int
 1294 selscan(td, ibits, obits, nfd)
 1295         struct thread *td;
 1296         fd_mask **ibits, **obits;
 1297         int nfd;
 1298 {
 1299         struct filedesc *fdp;
 1300         struct file *fp;
 1301         fd_mask bit;
 1302         int ev, flags, end, fd;
 1303         int n, idx;
 1304         int error;
 1305 
 1306         fdp = td->td_proc->p_fd;
 1307         n = 0;
 1308         for (idx = 0, fd = 0; fd < nfd; idx++) {
 1309                 end = imin(fd + NFDBITS, nfd);
 1310                 for (bit = 1; fd < end; bit <<= 1, fd++) {
 1311                         /* Compute the list of events we're interested in. */
 1312                         flags = selflags(ibits, idx, bit);
 1313                         if (flags == 0)
 1314                                 continue;
 1315                         error = getselfd_cap(fdp, fd, &fp);
 1316                         if (error)
 1317                                 return (error);
 1318                         selfdalloc(td, (void *)(uintptr_t)fd);
 1319                         ev = fo_poll(fp, flags, td->td_ucred, td);
 1320                         fdrop(fp, td);
 1321                         if (ev != 0)
 1322                                 n += selsetbits(ibits, obits, idx, bit, ev);
 1323                 }
 1324         }
 1325 
 1326         td->td_retval[0] = n;
 1327         return (0);
 1328 }
 1329 
 1330 int
 1331 sys_poll(struct thread *td, struct poll_args *uap)
 1332 {
 1333         struct timespec ts, *tsp;
 1334 
 1335         if (uap->timeout != INFTIM) {
 1336                 if (uap->timeout < 0)
 1337                         return (EINVAL);
 1338                 ts.tv_sec = uap->timeout / 1000;
 1339                 ts.tv_nsec = (uap->timeout % 1000) * 1000000;
 1340                 tsp = &ts;
 1341         } else
 1342                 tsp = NULL;
 1343 
 1344         return (kern_poll(td, uap->fds, uap->nfds, tsp, NULL));
 1345 }
 1346 
 1347 int
 1348 kern_poll(struct thread *td, struct pollfd *fds, u_int nfds,
 1349     struct timespec *tsp, sigset_t *uset)
 1350 {
 1351         struct pollfd *bits;
 1352         struct pollfd smallbits[32];
 1353         sbintime_t sbt, precision, tmp;
 1354         time_t over;
 1355         struct timespec ts;
 1356         int error;
 1357         size_t ni;
 1358 
 1359         precision = 0;
 1360         if (tsp != NULL) {
 1361                 if (tsp->tv_sec < 0)
 1362                         return (EINVAL);
 1363                 if (tsp->tv_nsec < 0 || tsp->tv_nsec >= 1000000000)
 1364                         return (EINVAL);
 1365                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
 1366                         sbt = 0;
 1367                 else {
 1368                         ts = *tsp;
 1369                         if (ts.tv_sec > INT32_MAX / 2) {
 1370                                 over = ts.tv_sec - INT32_MAX / 2;
 1371                                 ts.tv_sec -= over;
 1372                         } else
 1373                                 over = 0;
 1374                         tmp = tstosbt(ts);
 1375                         precision = tmp;
 1376                         precision >>= tc_precexp;
 1377                         if (TIMESEL(&sbt, tmp))
 1378                                 sbt += tc_tick_sbt;
 1379                         sbt += tmp;
 1380                 }
 1381         } else
 1382                 sbt = -1;
 1383 
 1384         if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 
 1385                 return (EINVAL);
 1386         ni = nfds * sizeof(struct pollfd);
 1387         if (ni > sizeof(smallbits))
 1388                 bits = malloc(ni, M_TEMP, M_WAITOK);
 1389         else
 1390                 bits = smallbits;
 1391         error = copyin(fds, bits, ni);
 1392         if (error)
 1393                 goto done;
 1394 
 1395         if (uset != NULL) {
 1396                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
 1397                     &td->td_oldsigmask, 0);
 1398                 if (error)
 1399                         goto done;
 1400                 td->td_pflags |= TDP_OLDMASK;
 1401                 /*
 1402                  * Make sure that ast() is called on return to
 1403                  * usermode and TDP_OLDMASK is cleared, restoring old
 1404                  * sigmask.
 1405                  */
 1406                 thread_lock(td);
 1407                 td->td_flags |= TDF_ASTPENDING;
 1408                 thread_unlock(td);
 1409         }
 1410 
 1411         seltdinit(td);
 1412         /* Iterate until the timeout expires or descriptors become ready. */
 1413         for (;;) {
 1414                 error = pollscan(td, bits, nfds);
 1415                 if (error || td->td_retval[0] != 0)
 1416                         break;
 1417                 error = seltdwait(td, sbt, precision);
 1418                 if (error)
 1419                         break;
 1420                 error = pollrescan(td);
 1421                 if (error || td->td_retval[0] != 0)
 1422                         break;
 1423         }
 1424         seltdclear(td);
 1425 
 1426 done:
 1427         /* poll is not restarted after signals... */
 1428         if (error == ERESTART)
 1429                 error = EINTR;
 1430         if (error == EWOULDBLOCK)
 1431                 error = 0;
 1432         if (error == 0) {
 1433                 error = pollout(td, bits, fds, nfds);
 1434                 if (error)
 1435                         goto out;
 1436         }
 1437 out:
 1438         if (ni > sizeof(smallbits))
 1439                 free(bits, M_TEMP);
 1440         return (error);
 1441 }
 1442 
 1443 int
 1444 sys_ppoll(struct thread *td, struct ppoll_args *uap)
 1445 {
 1446         struct timespec ts, *tsp;
 1447         sigset_t set, *ssp;
 1448         int error;
 1449 
 1450         if (uap->ts != NULL) {
 1451                 error = copyin(uap->ts, &ts, sizeof(ts));
 1452                 if (error)
 1453                         return (error);
 1454                 tsp = &ts;
 1455         } else
 1456                 tsp = NULL;
 1457         if (uap->set != NULL) {
 1458                 error = copyin(uap->set, &set, sizeof(set));
 1459                 if (error)
 1460                         return (error);
 1461                 ssp = &set;
 1462         } else
 1463                 ssp = NULL;
 1464         /*
 1465          * fds is still a pointer to user space. kern_poll() will
 1466          * take care of copyin that array to the kernel space.
 1467          */
 1468 
 1469         return (kern_poll(td, uap->fds, uap->nfds, tsp, ssp));
 1470 }
 1471 
 1472 static int
 1473 pollrescan(struct thread *td)
 1474 {
 1475         struct seltd *stp;
 1476         struct selfd *sfp;
 1477         struct selfd *sfn;
 1478         struct selinfo *si;
 1479         struct filedesc *fdp;
 1480         struct file *fp;
 1481         struct pollfd *fd;
 1482 #ifdef CAPABILITIES
 1483         cap_rights_t rights;
 1484 #endif
 1485         int n;
 1486 
 1487         n = 0;
 1488         fdp = td->td_proc->p_fd;
 1489         stp = td->td_sel;
 1490         FILEDESC_SLOCK(fdp);
 1491         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1492                 fd = (struct pollfd *)sfp->sf_cookie;
 1493                 si = sfp->sf_si;
 1494                 selfdfree(stp, sfp);
 1495                 /* If the selinfo wasn't cleared the event didn't fire. */
 1496                 if (si != NULL)
 1497                         continue;
 1498                 fp = fdp->fd_ofiles[fd->fd].fde_file;
 1499 #ifdef CAPABILITIES
 1500                 if (fp == NULL ||
 1501                     cap_check(cap_rights(fdp, fd->fd),
 1502                     cap_rights_init(&rights, CAP_EVENT)) != 0)
 1503 #else
 1504                 if (fp == NULL)
 1505 #endif
 1506                 {
 1507                         fd->revents = POLLNVAL;
 1508                         n++;
 1509                         continue;
 1510                 }
 1511 
 1512                 /*
 1513                  * Note: backend also returns POLLHUP and
 1514                  * POLLERR if appropriate.
 1515                  */
 1516                 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
 1517                 if (fd->revents != 0)
 1518                         n++;
 1519         }
 1520         FILEDESC_SUNLOCK(fdp);
 1521         stp->st_flags = 0;
 1522         td->td_retval[0] = n;
 1523         return (0);
 1524 }
 1525 
 1526 
 1527 static int
 1528 pollout(td, fds, ufds, nfd)
 1529         struct thread *td;
 1530         struct pollfd *fds;
 1531         struct pollfd *ufds;
 1532         u_int nfd;
 1533 {
 1534         int error = 0;
 1535         u_int i = 0;
 1536         u_int n = 0;
 1537 
 1538         for (i = 0; i < nfd; i++) {
 1539                 error = copyout(&fds->revents, &ufds->revents,
 1540                     sizeof(ufds->revents));
 1541                 if (error)
 1542                         return (error);
 1543                 if (fds->revents != 0)
 1544                         n++;
 1545                 fds++;
 1546                 ufds++;
 1547         }
 1548         td->td_retval[0] = n;
 1549         return (0);
 1550 }
 1551 
 1552 static int
 1553 pollscan(td, fds, nfd)
 1554         struct thread *td;
 1555         struct pollfd *fds;
 1556         u_int nfd;
 1557 {
 1558         struct filedesc *fdp = td->td_proc->p_fd;
 1559         struct file *fp;
 1560 #ifdef CAPABILITIES
 1561         cap_rights_t rights;
 1562 #endif
 1563         int i, n = 0;
 1564 
 1565         FILEDESC_SLOCK(fdp);
 1566         for (i = 0; i < nfd; i++, fds++) {
 1567                 if (fds->fd > fdp->fd_lastfile) {
 1568                         fds->revents = POLLNVAL;
 1569                         n++;
 1570                 } else if (fds->fd < 0) {
 1571                         fds->revents = 0;
 1572                 } else {
 1573                         fp = fdp->fd_ofiles[fds->fd].fde_file;
 1574 #ifdef CAPABILITIES
 1575                         if (fp == NULL ||
 1576                             cap_check(cap_rights(fdp, fds->fd),
 1577                             cap_rights_init(&rights, CAP_EVENT)) != 0)
 1578 #else
 1579                         if (fp == NULL)
 1580 #endif
 1581                         {
 1582                                 fds->revents = POLLNVAL;
 1583                                 n++;
 1584                         } else {
 1585                                 /*
 1586                                  * Note: backend also returns POLLHUP and
 1587                                  * POLLERR if appropriate.
 1588                                  */
 1589                                 selfdalloc(td, fds);
 1590                                 fds->revents = fo_poll(fp, fds->events,
 1591                                     td->td_ucred, td);
 1592                                 /*
 1593                                  * POSIX requires POLLOUT to be never
 1594                                  * set simultaneously with POLLHUP.
 1595                                  */
 1596                                 if ((fds->revents & POLLHUP) != 0)
 1597                                         fds->revents &= ~POLLOUT;
 1598 
 1599                                 if (fds->revents != 0)
 1600                                         n++;
 1601                         }
 1602                 }
 1603         }
 1604         FILEDESC_SUNLOCK(fdp);
 1605         td->td_retval[0] = n;
 1606         return (0);
 1607 }
 1608 
 1609 /*
 1610  * OpenBSD poll system call.
 1611  *
 1612  * XXX this isn't quite a true representation..  OpenBSD uses select ops.
 1613  */
 1614 #ifndef _SYS_SYSPROTO_H_
 1615 struct openbsd_poll_args {
 1616         struct pollfd *fds;
 1617         u_int   nfds;
 1618         int     timeout;
 1619 };
 1620 #endif
 1621 int
 1622 sys_openbsd_poll(td, uap)
 1623         register struct thread *td;
 1624         register struct openbsd_poll_args *uap;
 1625 {
 1626         return (sys_poll(td, (struct poll_args *)uap));
 1627 }
 1628 
 1629 /*
 1630  * XXX This was created specifically to support netncp and netsmb.  This
 1631  * allows the caller to specify a socket to wait for events on.  It returns
 1632  * 0 if any events matched and an error otherwise.  There is no way to
 1633  * determine which events fired.
 1634  */
 1635 int
 1636 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
 1637 {
 1638         struct timeval rtv;
 1639         sbintime_t asbt, precision, rsbt;
 1640         int error;
 1641 
 1642         precision = 0;  /* stupid gcc! */
 1643         if (tvp != NULL) {
 1644                 rtv = *tvp;
 1645                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 || 
 1646                     rtv.tv_usec >= 1000000)
 1647                         return (EINVAL);
 1648                 if (!timevalisset(&rtv))
 1649                         asbt = 0;
 1650                 else if (rtv.tv_sec <= INT32_MAX) {
 1651                         rsbt = tvtosbt(rtv);
 1652                         precision = rsbt;
 1653                         precision >>= tc_precexp;
 1654                         if (TIMESEL(&asbt, rsbt))
 1655                                 asbt += tc_tick_sbt;
 1656                         if (asbt <= SBT_MAX - rsbt)
 1657                                 asbt += rsbt;
 1658                         else
 1659                                 asbt = -1;
 1660                 } else
 1661                         asbt = -1;
 1662         } else
 1663                 asbt = -1;
 1664         seltdinit(td);
 1665         /*
 1666          * Iterate until the timeout expires or the socket becomes ready.
 1667          */
 1668         for (;;) {
 1669                 selfdalloc(td, NULL);
 1670                 error = sopoll(so, events, NULL, td);
 1671                 /* error here is actually the ready events. */
 1672                 if (error)
 1673                         return (0);
 1674                 error = seltdwait(td, asbt, precision);
 1675                 if (error)
 1676                         break;
 1677         }
 1678         seltdclear(td);
 1679         /* XXX Duplicates ncp/smb behavior. */
 1680         if (error == ERESTART)
 1681                 error = 0;
 1682         return (error);
 1683 }
 1684 
 1685 /*
 1686  * Preallocate two selfds associated with 'cookie'.  Some fo_poll routines
 1687  * have two select sets, one for read and another for write.
 1688  */
 1689 static void
 1690 selfdalloc(struct thread *td, void *cookie)
 1691 {
 1692         struct seltd *stp;
 1693 
 1694         stp = td->td_sel;
 1695         if (stp->st_free1 == NULL)
 1696                 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1697         stp->st_free1->sf_td = stp;
 1698         stp->st_free1->sf_cookie = cookie;
 1699         if (stp->st_free2 == NULL)
 1700                 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1701         stp->st_free2->sf_td = stp;
 1702         stp->st_free2->sf_cookie = cookie;
 1703 }
 1704 
 1705 static void
 1706 selfdfree(struct seltd *stp, struct selfd *sfp)
 1707 {
 1708         STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
 1709         if (sfp->sf_si != NULL) {
 1710                 mtx_lock(sfp->sf_mtx);
 1711                 if (sfp->sf_si != NULL) {
 1712                         TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
 1713                         refcount_release(&sfp->sf_refs);
 1714                 }
 1715                 mtx_unlock(sfp->sf_mtx);
 1716         }
 1717         if (refcount_release(&sfp->sf_refs))
 1718                 uma_zfree(selfd_zone, sfp);
 1719 }
 1720 
 1721 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */
 1722 void
 1723 seldrain(sip)
 1724         struct selinfo *sip;
 1725 {
 1726 
 1727         /*
 1728          * This feature is already provided by doselwakeup(), thus it is
 1729          * enough to go for it.
 1730          * Eventually, the context, should take care to avoid races
 1731          * between thread calling select()/poll() and file descriptor
 1732          * detaching, but, again, the races are just the same as
 1733          * selwakeup().
 1734          */
 1735         doselwakeup(sip, -1);
 1736 }
 1737 
 1738 /*
 1739  * Record a select request.
 1740  */
 1741 void
 1742 selrecord(selector, sip)
 1743         struct thread *selector;
 1744         struct selinfo *sip;
 1745 {
 1746         struct selfd *sfp;
 1747         struct seltd *stp;
 1748         struct mtx *mtxp;
 1749 
 1750         stp = selector->td_sel;
 1751         /*
 1752          * Don't record when doing a rescan.
 1753          */
 1754         if (stp->st_flags & SELTD_RESCAN)
 1755                 return;
 1756         /*
 1757          * Grab one of the preallocated descriptors.
 1758          */
 1759         sfp = NULL;
 1760         if ((sfp = stp->st_free1) != NULL)
 1761                 stp->st_free1 = NULL;
 1762         else if ((sfp = stp->st_free2) != NULL)
 1763                 stp->st_free2 = NULL;
 1764         else
 1765                 panic("selrecord: No free selfd on selq");
 1766         mtxp = sip->si_mtx;
 1767         if (mtxp == NULL)
 1768                 mtxp = mtx_pool_find(mtxpool_select, sip);
 1769         /*
 1770          * Initialize the sfp and queue it in the thread.
 1771          */
 1772         sfp->sf_si = sip;
 1773         sfp->sf_mtx = mtxp;
 1774         refcount_init(&sfp->sf_refs, 2);
 1775         STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
 1776         /*
 1777          * Now that we've locked the sip, check for initialization.
 1778          */
 1779         mtx_lock(mtxp);
 1780         if (sip->si_mtx == NULL) {
 1781                 sip->si_mtx = mtxp;
 1782                 TAILQ_INIT(&sip->si_tdlist);
 1783         }
 1784         /*
 1785          * Add this thread to the list of selfds listening on this selinfo.
 1786          */
 1787         TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
 1788         mtx_unlock(sip->si_mtx);
 1789 }
 1790 
 1791 /* Wake up a selecting thread. */
 1792 void
 1793 selwakeup(sip)
 1794         struct selinfo *sip;
 1795 {
 1796         doselwakeup(sip, -1);
 1797 }
 1798 
 1799 /* Wake up a selecting thread, and set its priority. */
 1800 void
 1801 selwakeuppri(sip, pri)
 1802         struct selinfo *sip;
 1803         int pri;
 1804 {
 1805         doselwakeup(sip, pri);
 1806 }
 1807 
 1808 /*
 1809  * Do a wakeup when a selectable event occurs.
 1810  */
 1811 static void
 1812 doselwakeup(sip, pri)
 1813         struct selinfo *sip;
 1814         int pri;
 1815 {
 1816         struct selfd *sfp;
 1817         struct selfd *sfn;
 1818         struct seltd *stp;
 1819 
 1820         /* If it's not initialized there can't be any waiters. */
 1821         if (sip->si_mtx == NULL)
 1822                 return;
 1823         /*
 1824          * Locking the selinfo locks all selfds associated with it.
 1825          */
 1826         mtx_lock(sip->si_mtx);
 1827         TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
 1828                 /*
 1829                  * Once we remove this sfp from the list and clear the
 1830                  * sf_si seltdclear will know to ignore this si.
 1831                  */
 1832                 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
 1833                 sfp->sf_si = NULL;
 1834                 stp = sfp->sf_td;
 1835                 mtx_lock(&stp->st_mtx);
 1836                 stp->st_flags |= SELTD_PENDING;
 1837                 cv_broadcastpri(&stp->st_wait, pri);
 1838                 mtx_unlock(&stp->st_mtx);
 1839                 if (refcount_release(&sfp->sf_refs))
 1840                         uma_zfree(selfd_zone, sfp);
 1841         }
 1842         mtx_unlock(sip->si_mtx);
 1843 }
 1844 
 1845 static void
 1846 seltdinit(struct thread *td)
 1847 {
 1848         struct seltd *stp;
 1849 
 1850         if ((stp = td->td_sel) != NULL)
 1851                 goto out;
 1852         td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
 1853         mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
 1854         cv_init(&stp->st_wait, "select");
 1855 out:
 1856         stp->st_flags = 0;
 1857         STAILQ_INIT(&stp->st_selq);
 1858 }
 1859 
 1860 static int
 1861 seltdwait(struct thread *td, sbintime_t sbt, sbintime_t precision)
 1862 {
 1863         struct seltd *stp;
 1864         int error;
 1865 
 1866         stp = td->td_sel;
 1867         /*
 1868          * An event of interest may occur while we do not hold the seltd
 1869          * locked so check the pending flag before we sleep.
 1870          */
 1871         mtx_lock(&stp->st_mtx);
 1872         /*
 1873          * Any further calls to selrecord will be a rescan.
 1874          */
 1875         stp->st_flags |= SELTD_RESCAN;
 1876         if (stp->st_flags & SELTD_PENDING) {
 1877                 mtx_unlock(&stp->st_mtx);
 1878                 return (0);
 1879         }
 1880         if (sbt == 0)
 1881                 error = EWOULDBLOCK;
 1882         else if (sbt != -1)
 1883                 error = cv_timedwait_sig_sbt(&stp->st_wait, &stp->st_mtx,
 1884                     sbt, precision, C_ABSOLUTE);
 1885         else
 1886                 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
 1887         mtx_unlock(&stp->st_mtx);
 1888 
 1889         return (error);
 1890 }
 1891 
 1892 void
 1893 seltdfini(struct thread *td)
 1894 {
 1895         struct seltd *stp;
 1896 
 1897         stp = td->td_sel;
 1898         if (stp == NULL)
 1899                 return;
 1900         if (stp->st_free1)
 1901                 uma_zfree(selfd_zone, stp->st_free1);
 1902         if (stp->st_free2)
 1903                 uma_zfree(selfd_zone, stp->st_free2);
 1904         td->td_sel = NULL;
 1905         cv_destroy(&stp->st_wait);
 1906         mtx_destroy(&stp->st_mtx);
 1907         free(stp, M_SELECT);
 1908 }
 1909 
 1910 /*
 1911  * Remove the references to the thread from all of the objects we were
 1912  * polling.
 1913  */
 1914 static void
 1915 seltdclear(struct thread *td)
 1916 {
 1917         struct seltd *stp;
 1918         struct selfd *sfp;
 1919         struct selfd *sfn;
 1920 
 1921         stp = td->td_sel;
 1922         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
 1923                 selfdfree(stp, sfp);
 1924         stp->st_flags = 0;
 1925 }
 1926 
 1927 static void selectinit(void *);
 1928 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
 1929 static void
 1930 selectinit(void *dummy __unused)
 1931 {
 1932 
 1933         selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
 1934             NULL, NULL, UMA_ALIGN_PTR, 0);
 1935         mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
 1936 }
 1937 
 1938 /*
 1939  * Set up a syscall return value that follows the convention specified for
 1940  * posix_* functions.
 1941  */
 1942 int
 1943 kern_posix_error(struct thread *td, int error)
 1944 {
 1945 
 1946         if (error <= 0)
 1947                 return (error);
 1948         td->td_errno = error;
 1949         td->td_pflags |= TDP_NERRNO;
 1950         td->td_retval[0] = error;
 1951         return (0);
 1952 }

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