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/11.0/sys/kern/sys_generic.c 297493 2016-04-01 18:29:38Z jhb $");
   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(td, uap)
  224         struct thread *td;
  225         struct pread_args *uap;
  226 {
  227         struct uio auio;
  228         struct iovec aiov;
  229         int error;
  230 
  231         if (uap->nbyte > IOSIZE_MAX)
  232                 return (EINVAL);
  233         aiov.iov_base = uap->buf;
  234         aiov.iov_len = uap->nbyte;
  235         auio.uio_iov = &aiov;
  236         auio.uio_iovcnt = 1;
  237         auio.uio_resid = uap->nbyte;
  238         auio.uio_segflg = UIO_USERSPACE;
  239         error = kern_preadv(td, uap->fd, &auio, uap->offset);
  240         return(error);
  241 }
  242 
  243 #if defined(COMPAT_FREEBSD6)
  244 int
  245 freebsd6_pread(td, uap)
  246         struct thread *td;
  247         struct freebsd6_pread_args *uap;
  248 {
  249         struct pread_args oargs;
  250 
  251         oargs.fd = uap->fd;
  252         oargs.buf = uap->buf;
  253         oargs.nbyte = uap->nbyte;
  254         oargs.offset = uap->offset;
  255         return (sys_pread(td, &oargs));
  256 }
  257 #endif
  258 
  259 /*
  260  * Scatter read system call.
  261  */
  262 #ifndef _SYS_SYSPROTO_H_
  263 struct readv_args {
  264         int     fd;
  265         struct  iovec *iovp;
  266         u_int   iovcnt;
  267 };
  268 #endif
  269 int
  270 sys_readv(struct thread *td, struct readv_args *uap)
  271 {
  272         struct uio *auio;
  273         int error;
  274 
  275         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  276         if (error)
  277                 return (error);
  278         error = kern_readv(td, uap->fd, auio);
  279         free(auio, M_IOV);
  280         return (error);
  281 }
  282 
  283 int
  284 kern_readv(struct thread *td, int fd, struct uio *auio)
  285 {
  286         struct file *fp;
  287         cap_rights_t rights;
  288         int error;
  289 
  290         error = fget_read(td, fd, cap_rights_init(&rights, CAP_READ), &fp);
  291         if (error)
  292                 return (error);
  293         error = dofileread(td, fd, fp, auio, (off_t)-1, 0);
  294         fdrop(fp, td);
  295         return (error);
  296 }
  297 
  298 /*
  299  * Scatter positioned read system call.
  300  */
  301 #ifndef _SYS_SYSPROTO_H_
  302 struct preadv_args {
  303         int     fd;
  304         struct  iovec *iovp;
  305         u_int   iovcnt;
  306         off_t   offset;
  307 };
  308 #endif
  309 int
  310 sys_preadv(struct thread *td, struct preadv_args *uap)
  311 {
  312         struct uio *auio;
  313         int error;
  314 
  315         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  316         if (error)
  317                 return (error);
  318         error = kern_preadv(td, uap->fd, auio, uap->offset);
  319         free(auio, M_IOV);
  320         return (error);
  321 }
  322 
  323 int
  324 kern_preadv(td, fd, auio, offset)
  325         struct thread *td;
  326         int fd;
  327         struct uio *auio;
  328         off_t offset;
  329 {
  330         struct file *fp;
  331         cap_rights_t rights;
  332         int error;
  333 
  334         error = fget_read(td, fd, cap_rights_init(&rights, CAP_PREAD), &fp);
  335         if (error)
  336                 return (error);
  337         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  338                 error = ESPIPE;
  339         else if (offset < 0 && fp->f_vnode->v_type != VCHR)
  340                 error = EINVAL;
  341         else
  342                 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET);
  343         fdrop(fp, td);
  344         return (error);
  345 }
  346 
  347 /*
  348  * Common code for readv and preadv that reads data in
  349  * from a file using the passed in uio, offset, and flags.
  350  */
  351 static int
  352 dofileread(td, fd, fp, auio, offset, flags)
  353         struct thread *td;
  354         int fd;
  355         struct file *fp;
  356         struct uio *auio;
  357         off_t offset;
  358         int flags;
  359 {
  360         ssize_t cnt;
  361         int error;
  362 #ifdef KTRACE
  363         struct uio *ktruio = NULL;
  364 #endif
  365 
  366         /* Finish zero length reads right here */
  367         if (auio->uio_resid == 0) {
  368                 td->td_retval[0] = 0;
  369                 return(0);
  370         }
  371         auio->uio_rw = UIO_READ;
  372         auio->uio_offset = offset;
  373         auio->uio_td = td;
  374 #ifdef KTRACE
  375         if (KTRPOINT(td, KTR_GENIO)) 
  376                 ktruio = cloneuio(auio);
  377 #endif
  378         cnt = auio->uio_resid;
  379         if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) {
  380                 if (auio->uio_resid != cnt && (error == ERESTART ||
  381                     error == EINTR || error == EWOULDBLOCK))
  382                         error = 0;
  383         }
  384         cnt -= auio->uio_resid;
  385 #ifdef KTRACE
  386         if (ktruio != NULL) {
  387                 ktruio->uio_resid = cnt;
  388                 ktrgenio(fd, UIO_READ, ktruio, error);
  389         }
  390 #endif
  391         td->td_retval[0] = cnt;
  392         return (error);
  393 }
  394 
  395 #ifndef _SYS_SYSPROTO_H_
  396 struct write_args {
  397         int     fd;
  398         const void *buf;
  399         size_t  nbyte;
  400 };
  401 #endif
  402 int
  403 sys_write(td, uap)
  404         struct thread *td;
  405         struct write_args *uap;
  406 {
  407         struct uio auio;
  408         struct iovec aiov;
  409         int error;
  410 
  411         if (uap->nbyte > IOSIZE_MAX)
  412                 return (EINVAL);
  413         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  414         aiov.iov_len = uap->nbyte;
  415         auio.uio_iov = &aiov;
  416         auio.uio_iovcnt = 1;
  417         auio.uio_resid = uap->nbyte;
  418         auio.uio_segflg = UIO_USERSPACE;
  419         error = kern_writev(td, uap->fd, &auio);
  420         return(error);
  421 }
  422 
  423 /*
  424  * Positioned write system call.
  425  */
  426 #ifndef _SYS_SYSPROTO_H_
  427 struct pwrite_args {
  428         int     fd;
  429         const void *buf;
  430         size_t  nbyte;
  431         int     pad;
  432         off_t   offset;
  433 };
  434 #endif
  435 int
  436 sys_pwrite(td, uap)
  437         struct thread *td;
  438         struct pwrite_args *uap;
  439 {
  440         struct uio auio;
  441         struct iovec aiov;
  442         int error;
  443 
  444         if (uap->nbyte > IOSIZE_MAX)
  445                 return (EINVAL);
  446         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  447         aiov.iov_len = uap->nbyte;
  448         auio.uio_iov = &aiov;
  449         auio.uio_iovcnt = 1;
  450         auio.uio_resid = uap->nbyte;
  451         auio.uio_segflg = UIO_USERSPACE;
  452         error = kern_pwritev(td, uap->fd, &auio, uap->offset);
  453         return(error);
  454 }
  455 
  456 #if defined(COMPAT_FREEBSD6)
  457 int
  458 freebsd6_pwrite(td, uap)
  459         struct thread *td;
  460         struct freebsd6_pwrite_args *uap;
  461 {
  462         struct pwrite_args oargs;
  463 
  464         oargs.fd = uap->fd;
  465         oargs.buf = uap->buf;
  466         oargs.nbyte = uap->nbyte;
  467         oargs.offset = uap->offset;
  468         return (sys_pwrite(td, &oargs));
  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 && fp->f_vnode->v_type != VCHR)
  553                 error = EINVAL;
  554         else
  555                 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET);
  556         fdrop(fp, td);
  557         return (error);
  558 }
  559 
  560 /*
  561  * Common code for writev and pwritev that writes data to
  562  * a file using the passed in uio, offset, and flags.
  563  */
  564 static int
  565 dofilewrite(td, fd, fp, auio, offset, flags)
  566         struct thread *td;
  567         int fd;
  568         struct file *fp;
  569         struct uio *auio;
  570         off_t offset;
  571         int flags;
  572 {
  573         ssize_t cnt;
  574         int error;
  575 #ifdef KTRACE
  576         struct uio *ktruio = NULL;
  577 #endif
  578 
  579         auio->uio_rw = UIO_WRITE;
  580         auio->uio_td = td;
  581         auio->uio_offset = offset;
  582 #ifdef KTRACE
  583         if (KTRPOINT(td, KTR_GENIO))
  584                 ktruio = cloneuio(auio);
  585 #endif
  586         cnt = auio->uio_resid;
  587         if (fp->f_type == DTYPE_VNODE &&
  588             (fp->f_vnread_flags & FDEVFS_VNODE) == 0)
  589                 bwillwrite();
  590         if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) {
  591                 if (auio->uio_resid != cnt && (error == ERESTART ||
  592                     error == EINTR || error == EWOULDBLOCK))
  593                         error = 0;
  594                 /* Socket layer is responsible for issuing SIGPIPE. */
  595                 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) {
  596                         PROC_LOCK(td->td_proc);
  597                         tdsignal(td, SIGPIPE);
  598                         PROC_UNLOCK(td->td_proc);
  599                 }
  600         }
  601         cnt -= auio->uio_resid;
  602 #ifdef KTRACE
  603         if (ktruio != NULL) {
  604                 ktruio->uio_resid = cnt;
  605                 ktrgenio(fd, UIO_WRITE, ktruio, error);
  606         }
  607 #endif
  608         td->td_retval[0] = cnt;
  609         return (error);
  610 }
  611 
  612 /*
  613  * Truncate a file given a file descriptor.
  614  *
  615  * Can't use fget_write() here, since must return EINVAL and not EBADF if the
  616  * descriptor isn't writable.
  617  */
  618 int
  619 kern_ftruncate(td, fd, length)
  620         struct thread *td;
  621         int fd;
  622         off_t length;
  623 {
  624         struct file *fp;
  625         cap_rights_t rights;
  626         int error;
  627 
  628         AUDIT_ARG_FD(fd);
  629         if (length < 0)
  630                 return (EINVAL);
  631         error = fget(td, fd, cap_rights_init(&rights, CAP_FTRUNCATE), &fp);
  632         if (error)
  633                 return (error);
  634         AUDIT_ARG_FILE(td->td_proc, fp);
  635         if (!(fp->f_flag & FWRITE)) {
  636                 fdrop(fp, td);
  637                 return (EINVAL);
  638         }
  639         error = fo_truncate(fp, length, td->td_ucred, td);
  640         fdrop(fp, td);
  641         return (error);
  642 }
  643 
  644 #ifndef _SYS_SYSPROTO_H_
  645 struct ftruncate_args {
  646         int     fd;
  647         int     pad;
  648         off_t   length;
  649 };
  650 #endif
  651 int
  652 sys_ftruncate(td, uap)
  653         struct thread *td;
  654         struct ftruncate_args *uap;
  655 {
  656 
  657         return (kern_ftruncate(td, uap->fd, uap->length));
  658 }
  659 
  660 #if defined(COMPAT_43)
  661 #ifndef _SYS_SYSPROTO_H_
  662 struct oftruncate_args {
  663         int     fd;
  664         long    length;
  665 };
  666 #endif
  667 int
  668 oftruncate(td, uap)
  669         struct thread *td;
  670         struct oftruncate_args *uap;
  671 {
  672 
  673         return (kern_ftruncate(td, uap->fd, uap->length));
  674 }
  675 #endif /* COMPAT_43 */
  676 
  677 #ifndef _SYS_SYSPROTO_H_
  678 struct ioctl_args {
  679         int     fd;
  680         u_long  com;
  681         caddr_t data;
  682 };
  683 #endif
  684 /* ARGSUSED */
  685 int
  686 sys_ioctl(struct thread *td, struct ioctl_args *uap)
  687 {
  688         u_char smalldata[SYS_IOCTL_SMALL_SIZE] __aligned(SYS_IOCTL_SMALL_ALIGN);
  689         u_long com;
  690         int arg, error;
  691         u_int size;
  692         caddr_t data;
  693 
  694         if (uap->com > 0xffffffff) {
  695                 printf(
  696                     "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
  697                     td->td_proc->p_pid, td->td_name, uap->com);
  698                 uap->com &= 0xffffffff;
  699         }
  700         com = uap->com;
  701 
  702         /*
  703          * Interpret high order word to find amount of data to be
  704          * copied to/from the user's address space.
  705          */
  706         size = IOCPARM_LEN(com);
  707         if ((size > IOCPARM_MAX) ||
  708             ((com & (IOC_VOID  | IOC_IN | IOC_OUT)) == 0) ||
  709 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
  710             ((com & IOC_OUT) && size == 0) ||
  711 #else
  712             ((com & (IOC_IN | IOC_OUT)) && size == 0) ||
  713 #endif
  714             ((com & IOC_VOID) && size > 0 && size != sizeof(int)))
  715                 return (ENOTTY);
  716 
  717         if (size > 0) {
  718                 if (com & IOC_VOID) {
  719                         /* Integer argument. */
  720                         arg = (intptr_t)uap->data;
  721                         data = (void *)&arg;
  722                         size = 0;
  723                 } else {
  724                         if (size > SYS_IOCTL_SMALL_SIZE)
  725                                 data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
  726                         else
  727                                 data = smalldata;
  728                 }
  729         } else
  730                 data = (void *)&uap->data;
  731         if (com & IOC_IN) {
  732                 error = copyin(uap->data, data, (u_int)size);
  733                 if (error != 0)
  734                         goto out;
  735         } else if (com & IOC_OUT) {
  736                 /*
  737                  * Zero the buffer so the user always
  738                  * gets back something deterministic.
  739                  */
  740                 bzero(data, size);
  741         }
  742 
  743         error = kern_ioctl(td, uap->fd, com, data);
  744 
  745         if (error == 0 && (com & IOC_OUT))
  746                 error = copyout(data, uap->data, (u_int)size);
  747 
  748 out:
  749         if (size > SYS_IOCTL_SMALL_SIZE)
  750                 free(data, M_IOCTLOPS);
  751         return (error);
  752 }
  753 
  754 int
  755 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
  756 {
  757         struct file *fp;
  758         struct filedesc *fdp;
  759 #ifndef CAPABILITIES
  760         cap_rights_t rights;
  761 #endif
  762         int error, tmp, locked;
  763 
  764         AUDIT_ARG_FD(fd);
  765         AUDIT_ARG_CMD(com);
  766 
  767         fdp = td->td_proc->p_fd;
  768 
  769         switch (com) {
  770         case FIONCLEX:
  771         case FIOCLEX:
  772                 FILEDESC_XLOCK(fdp);
  773                 locked = LA_XLOCKED;
  774                 break;
  775         default:
  776 #ifdef CAPABILITIES
  777                 FILEDESC_SLOCK(fdp);
  778                 locked = LA_SLOCKED;
  779 #else
  780                 locked = LA_UNLOCKED;
  781 #endif
  782                 break;
  783         }
  784 
  785 #ifdef CAPABILITIES
  786         if ((fp = fget_locked(fdp, fd)) == NULL) {
  787                 error = EBADF;
  788                 goto out;
  789         }
  790         if ((error = cap_ioctl_check(fdp, fd, com)) != 0) {
  791                 fp = NULL;      /* fhold() was not called yet */
  792                 goto out;
  793         }
  794         fhold(fp);
  795         if (locked == LA_SLOCKED) {
  796                 FILEDESC_SUNLOCK(fdp);
  797                 locked = LA_UNLOCKED;
  798         }
  799 #else
  800         error = fget(td, fd, cap_rights_init(&rights, CAP_IOCTL), &fp);
  801         if (error != 0) {
  802                 fp = NULL;
  803                 goto out;
  804         }
  805 #endif
  806         if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
  807                 error = EBADF;
  808                 goto out;
  809         }
  810 
  811         switch (com) {
  812         case FIONCLEX:
  813                 fdp->fd_ofiles[fd].fde_flags &= ~UF_EXCLOSE;
  814                 goto out;
  815         case FIOCLEX:
  816                 fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE;
  817                 goto out;
  818         case FIONBIO:
  819                 if ((tmp = *(int *)data))
  820                         atomic_set_int(&fp->f_flag, FNONBLOCK);
  821                 else
  822                         atomic_clear_int(&fp->f_flag, FNONBLOCK);
  823                 data = (void *)&tmp;
  824                 break;
  825         case FIOASYNC:
  826                 if ((tmp = *(int *)data))
  827                         atomic_set_int(&fp->f_flag, FASYNC);
  828                 else
  829                         atomic_clear_int(&fp->f_flag, FASYNC);
  830                 data = (void *)&tmp;
  831                 break;
  832         }
  833 
  834         error = fo_ioctl(fp, com, data, td->td_ucred, td);
  835 out:
  836         switch (locked) {
  837         case LA_XLOCKED:
  838                 FILEDESC_XUNLOCK(fdp);
  839                 break;
  840 #ifdef CAPABILITIES
  841         case LA_SLOCKED:
  842                 FILEDESC_SUNLOCK(fdp);
  843                 break;
  844 #endif
  845         default:
  846                 FILEDESC_UNLOCK_ASSERT(fdp);
  847                 break;
  848         }
  849         if (fp != NULL)
  850                 fdrop(fp, td);
  851         return (error);
  852 }
  853 
  854 int
  855 poll_no_poll(int events)
  856 {
  857         /*
  858          * Return true for read/write.  If the user asked for something
  859          * special, return POLLNVAL, so that clients have a way of
  860          * determining reliably whether or not the extended
  861          * functionality is present without hard-coding knowledge
  862          * of specific filesystem implementations.
  863          */
  864         if (events & ~POLLSTANDARD)
  865                 return (POLLNVAL);
  866 
  867         return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
  868 }
  869 
  870 int
  871 sys_pselect(struct thread *td, struct pselect_args *uap)
  872 {
  873         struct timespec ts;
  874         struct timeval tv, *tvp;
  875         sigset_t set, *uset;
  876         int error;
  877 
  878         if (uap->ts != NULL) {
  879                 error = copyin(uap->ts, &ts, sizeof(ts));
  880                 if (error != 0)
  881                     return (error);
  882                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
  883                 tvp = &tv;
  884         } else
  885                 tvp = NULL;
  886         if (uap->sm != NULL) {
  887                 error = copyin(uap->sm, &set, sizeof(set));
  888                 if (error != 0)
  889                         return (error);
  890                 uset = &set;
  891         } else
  892                 uset = NULL;
  893         return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  894             uset, NFDBITS));
  895 }
  896 
  897 int
  898 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
  899     struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
  900 {
  901         int error;
  902 
  903         if (uset != NULL) {
  904                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
  905                     &td->td_oldsigmask, 0);
  906                 if (error != 0)
  907                         return (error);
  908                 td->td_pflags |= TDP_OLDMASK;
  909                 /*
  910                  * Make sure that ast() is called on return to
  911                  * usermode and TDP_OLDMASK is cleared, restoring old
  912                  * sigmask.
  913                  */
  914                 thread_lock(td);
  915                 td->td_flags |= TDF_ASTPENDING;
  916                 thread_unlock(td);
  917         }
  918         error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
  919         return (error);
  920 }
  921 
  922 #ifndef _SYS_SYSPROTO_H_
  923 struct select_args {
  924         int     nd;
  925         fd_set  *in, *ou, *ex;
  926         struct  timeval *tv;
  927 };
  928 #endif
  929 int
  930 sys_select(struct thread *td, struct select_args *uap)
  931 {
  932         struct timeval tv, *tvp;
  933         int error;
  934 
  935         if (uap->tv != NULL) {
  936                 error = copyin(uap->tv, &tv, sizeof(tv));
  937                 if (error)
  938                         return (error);
  939                 tvp = &tv;
  940         } else
  941                 tvp = NULL;
  942 
  943         return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  944             NFDBITS));
  945 }
  946 
  947 /*
  948  * In the unlikely case when user specified n greater then the last
  949  * open file descriptor, check that no bits are set after the last
  950  * valid fd.  We must return EBADF if any is set.
  951  *
  952  * There are applications that rely on the behaviour.
  953  *
  954  * nd is fd_lastfile + 1.
  955  */
  956 static int
  957 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits)
  958 {
  959         char *addr, *oaddr;
  960         int b, i, res;
  961         uint8_t bits;
  962 
  963         if (nd >= ndu || fd_in == NULL)
  964                 return (0);
  965 
  966         oaddr = NULL;
  967         bits = 0; /* silence gcc */
  968         for (i = nd; i < ndu; i++) {
  969                 b = i / NBBY;
  970 #if BYTE_ORDER == LITTLE_ENDIAN
  971                 addr = (char *)fd_in + b;
  972 #else
  973                 addr = (char *)fd_in;
  974                 if (abi_nfdbits == NFDBITS) {
  975                         addr += rounddown(b, sizeof(fd_mask)) +
  976                             sizeof(fd_mask) - 1 - b % sizeof(fd_mask);
  977                 } else {
  978                         addr += rounddown(b, sizeof(uint32_t)) +
  979                             sizeof(uint32_t) - 1 - b % sizeof(uint32_t);
  980                 }
  981 #endif
  982                 if (addr != oaddr) {
  983                         res = fubyte(addr);
  984                         if (res == -1)
  985                                 return (EFAULT);
  986                         oaddr = addr;
  987                         bits = res;
  988                 }
  989                 if ((bits & (1 << (i % NBBY))) != 0)
  990                         return (EBADF);
  991         }
  992         return (0);
  993 }
  994 
  995 int
  996 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
  997     fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
  998 {
  999         struct filedesc *fdp;
 1000         /*
 1001          * The magic 2048 here is chosen to be just enough for FD_SETSIZE
 1002          * infds with the new FD_SETSIZE of 1024, and more than enough for
 1003          * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
 1004          * of 256.
 1005          */
 1006         fd_mask s_selbits[howmany(2048, NFDBITS)];
 1007         fd_mask *ibits[3], *obits[3], *selbits, *sbp;
 1008         struct timeval rtv;
 1009         sbintime_t asbt, precision, rsbt;
 1010         u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
 1011         int error, lf, ndu;
 1012 
 1013         if (nd < 0)
 1014                 return (EINVAL);
 1015         fdp = td->td_proc->p_fd;
 1016         ndu = nd;
 1017         lf = fdp->fd_lastfile;
 1018         if (nd > lf + 1)
 1019                 nd = lf + 1;
 1020 
 1021         error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits);
 1022         if (error != 0)
 1023                 return (error);
 1024         error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits);
 1025         if (error != 0)
 1026                 return (error);
 1027         error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits);
 1028         if (error != 0)
 1029                 return (error);
 1030 
 1031         /*
 1032          * Allocate just enough bits for the non-null fd_sets.  Use the
 1033          * preallocated auto buffer if possible.
 1034          */
 1035         nfdbits = roundup(nd, NFDBITS);
 1036         ncpbytes = nfdbits / NBBY;
 1037         ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
 1038         nbufbytes = 0;
 1039         if (fd_in != NULL)
 1040                 nbufbytes += 2 * ncpbytes;
 1041         if (fd_ou != NULL)
 1042                 nbufbytes += 2 * ncpbytes;
 1043         if (fd_ex != NULL)
 1044                 nbufbytes += 2 * ncpbytes;
 1045         if (nbufbytes <= sizeof s_selbits)
 1046                 selbits = &s_selbits[0];
 1047         else
 1048                 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
 1049 
 1050         /*
 1051          * Assign pointers into the bit buffers and fetch the input bits.
 1052          * Put the output buffers together so that they can be bzeroed
 1053          * together.
 1054          */
 1055         sbp = selbits;
 1056 #define getbits(name, x) \
 1057         do {                                                            \
 1058                 if (name == NULL) {                                     \
 1059                         ibits[x] = NULL;                                \
 1060                         obits[x] = NULL;                                \
 1061                 } else {                                                \
 1062                         ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp;   \
 1063                         obits[x] = sbp;                                 \
 1064                         sbp += ncpbytes / sizeof *sbp;                  \
 1065                         error = copyin(name, ibits[x], ncpubytes);      \
 1066                         if (error != 0)                                 \
 1067                                 goto done;                              \
 1068                         bzero((char *)ibits[x] + ncpubytes,             \
 1069                             ncpbytes - ncpubytes);                      \
 1070                 }                                                       \
 1071         } while (0)
 1072         getbits(fd_in, 0);
 1073         getbits(fd_ou, 1);
 1074         getbits(fd_ex, 2);
 1075 #undef  getbits
 1076 
 1077 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
 1078         /*
 1079          * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
 1080          * we are running under 32-bit emulation. This should be more
 1081          * generic.
 1082          */
 1083 #define swizzle_fdset(bits)                                             \
 1084         if (abi_nfdbits != NFDBITS && bits != NULL) {                   \
 1085                 int i;                                                  \
 1086                 for (i = 0; i < ncpbytes / sizeof *sbp; i++)            \
 1087                         bits[i] = (bits[i] >> 32) | (bits[i] << 32);    \
 1088         }
 1089 #else
 1090 #define swizzle_fdset(bits)
 1091 #endif
 1092 
 1093         /* Make sure the bit order makes it through an ABI transition */
 1094         swizzle_fdset(ibits[0]);
 1095         swizzle_fdset(ibits[1]);
 1096         swizzle_fdset(ibits[2]);
 1097         
 1098         if (nbufbytes != 0)
 1099                 bzero(selbits, nbufbytes / 2);
 1100 
 1101         precision = 0;
 1102         if (tvp != NULL) {
 1103                 rtv = *tvp;
 1104                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
 1105                     rtv.tv_usec >= 1000000) {
 1106                         error = EINVAL;
 1107                         goto done;
 1108                 }
 1109                 if (!timevalisset(&rtv))
 1110                         asbt = 0;
 1111                 else if (rtv.tv_sec <= INT32_MAX) {
 1112                         rsbt = tvtosbt(rtv);
 1113                         precision = rsbt;
 1114                         precision >>= tc_precexp;
 1115                         if (TIMESEL(&asbt, rsbt))
 1116                                 asbt += tc_tick_sbt;
 1117                         if (asbt <= SBT_MAX - rsbt)
 1118                                 asbt += rsbt;
 1119                         else
 1120                                 asbt = -1;
 1121                 } else
 1122                         asbt = -1;
 1123         } else
 1124                 asbt = -1;
 1125         seltdinit(td);
 1126         /* Iterate until the timeout expires or descriptors become ready. */
 1127         for (;;) {
 1128                 error = selscan(td, ibits, obits, nd);
 1129                 if (error || td->td_retval[0] != 0)
 1130                         break;
 1131                 error = seltdwait(td, asbt, precision);
 1132                 if (error)
 1133                         break;
 1134                 error = selrescan(td, ibits, obits);
 1135                 if (error || td->td_retval[0] != 0)
 1136                         break;
 1137         }
 1138         seltdclear(td);
 1139 
 1140 done:
 1141         /* select is not restarted after signals... */
 1142         if (error == ERESTART)
 1143                 error = EINTR;
 1144         if (error == EWOULDBLOCK)
 1145                 error = 0;
 1146 
 1147         /* swizzle bit order back, if necessary */
 1148         swizzle_fdset(obits[0]);
 1149         swizzle_fdset(obits[1]);
 1150         swizzle_fdset(obits[2]);
 1151 #undef swizzle_fdset
 1152 
 1153 #define putbits(name, x) \
 1154         if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
 1155                 error = error2;
 1156         if (error == 0) {
 1157                 int error2;
 1158 
 1159                 putbits(fd_in, 0);
 1160                 putbits(fd_ou, 1);
 1161                 putbits(fd_ex, 2);
 1162 #undef putbits
 1163         }
 1164         if (selbits != &s_selbits[0])
 1165                 free(selbits, M_SELECT);
 1166 
 1167         return (error);
 1168 }
 1169 /* 
 1170  * Convert a select bit set to poll flags.
 1171  *
 1172  * The backend always returns POLLHUP/POLLERR if appropriate and we
 1173  * return this as a set bit in any set.
 1174  */
 1175 static int select_flags[3] = {
 1176     POLLRDNORM | POLLHUP | POLLERR,
 1177     POLLWRNORM | POLLHUP | POLLERR,
 1178     POLLRDBAND | POLLERR
 1179 };
 1180 
 1181 /*
 1182  * Compute the fo_poll flags required for a fd given by the index and
 1183  * bit position in the fd_mask array.
 1184  */
 1185 static __inline int
 1186 selflags(fd_mask **ibits, int idx, fd_mask bit)
 1187 {
 1188         int flags;
 1189         int msk;
 1190 
 1191         flags = 0;
 1192         for (msk = 0; msk < 3; msk++) {
 1193                 if (ibits[msk] == NULL)
 1194                         continue;
 1195                 if ((ibits[msk][idx] & bit) == 0)
 1196                         continue;
 1197                 flags |= select_flags[msk];
 1198         }
 1199         return (flags);
 1200 }
 1201 
 1202 /*
 1203  * Set the appropriate output bits given a mask of fired events and the
 1204  * input bits originally requested.
 1205  */
 1206 static __inline int
 1207 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
 1208 {
 1209         int msk;
 1210         int n;
 1211 
 1212         n = 0;
 1213         for (msk = 0; msk < 3; msk++) {
 1214                 if ((events & select_flags[msk]) == 0)
 1215                         continue;
 1216                 if (ibits[msk] == NULL)
 1217                         continue;
 1218                 if ((ibits[msk][idx] & bit) == 0)
 1219                         continue;
 1220                 /*
 1221                  * XXX Check for a duplicate set.  This can occur because a
 1222                  * socket calls selrecord() twice for each poll() call
 1223                  * resulting in two selfds per real fd.  selrescan() will
 1224                  * call selsetbits twice as a result.
 1225                  */
 1226                 if ((obits[msk][idx] & bit) != 0)
 1227                         continue;
 1228                 obits[msk][idx] |= bit;
 1229                 n++;
 1230         }
 1231 
 1232         return (n);
 1233 }
 1234 
 1235 static __inline int
 1236 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp)
 1237 {
 1238         cap_rights_t rights;
 1239 
 1240         cap_rights_init(&rights, CAP_EVENT);
 1241 
 1242         return (fget_unlocked(fdp, fd, &rights, fpp, NULL));
 1243 }
 1244 
 1245 /*
 1246  * Traverse the list of fds attached to this thread's seltd and check for
 1247  * completion.
 1248  */
 1249 static int
 1250 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
 1251 {
 1252         struct filedesc *fdp;
 1253         struct selinfo *si;
 1254         struct seltd *stp;
 1255         struct selfd *sfp;
 1256         struct selfd *sfn;
 1257         struct file *fp;
 1258         fd_mask bit;
 1259         int fd, ev, n, idx;
 1260         int error;
 1261 
 1262         fdp = td->td_proc->p_fd;
 1263         stp = td->td_sel;
 1264         n = 0;
 1265         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1266                 fd = (int)(uintptr_t)sfp->sf_cookie;
 1267                 si = sfp->sf_si;
 1268                 selfdfree(stp, sfp);
 1269                 /* If the selinfo wasn't cleared the event didn't fire. */
 1270                 if (si != NULL)
 1271                         continue;
 1272                 error = getselfd_cap(fdp, fd, &fp);
 1273                 if (error)
 1274                         return (error);
 1275                 idx = fd / NFDBITS;
 1276                 bit = (fd_mask)1 << (fd % NFDBITS);
 1277                 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
 1278                 fdrop(fp, td);
 1279                 if (ev != 0)
 1280                         n += selsetbits(ibits, obits, idx, bit, ev);
 1281         }
 1282         stp->st_flags = 0;
 1283         td->td_retval[0] = n;
 1284         return (0);
 1285 }
 1286 
 1287 /*
 1288  * Perform the initial filedescriptor scan and register ourselves with
 1289  * each selinfo.
 1290  */
 1291 static int
 1292 selscan(td, ibits, obits, nfd)
 1293         struct thread *td;
 1294         fd_mask **ibits, **obits;
 1295         int nfd;
 1296 {
 1297         struct filedesc *fdp;
 1298         struct file *fp;
 1299         fd_mask bit;
 1300         int ev, flags, end, fd;
 1301         int n, idx;
 1302         int error;
 1303 
 1304         fdp = td->td_proc->p_fd;
 1305         n = 0;
 1306         for (idx = 0, fd = 0; fd < nfd; idx++) {
 1307                 end = imin(fd + NFDBITS, nfd);
 1308                 for (bit = 1; fd < end; bit <<= 1, fd++) {
 1309                         /* Compute the list of events we're interested in. */
 1310                         flags = selflags(ibits, idx, bit);
 1311                         if (flags == 0)
 1312                                 continue;
 1313                         error = getselfd_cap(fdp, fd, &fp);
 1314                         if (error)
 1315                                 return (error);
 1316                         selfdalloc(td, (void *)(uintptr_t)fd);
 1317                         ev = fo_poll(fp, flags, td->td_ucred, td);
 1318                         fdrop(fp, td);
 1319                         if (ev != 0)
 1320                                 n += selsetbits(ibits, obits, idx, bit, ev);
 1321                 }
 1322         }
 1323 
 1324         td->td_retval[0] = n;
 1325         return (0);
 1326 }
 1327 
 1328 int
 1329 sys_poll(struct thread *td, struct poll_args *uap)
 1330 {
 1331         struct timespec ts, *tsp;
 1332 
 1333         if (uap->timeout != INFTIM) {
 1334                 if (uap->timeout < 0)
 1335                         return (EINVAL);
 1336                 ts.tv_sec = uap->timeout / 1000;
 1337                 ts.tv_nsec = (uap->timeout % 1000) * 1000000;
 1338                 tsp = &ts;
 1339         } else
 1340                 tsp = NULL;
 1341 
 1342         return (kern_poll(td, uap->fds, uap->nfds, tsp, NULL));
 1343 }
 1344 
 1345 int
 1346 kern_poll(struct thread *td, struct pollfd *fds, u_int nfds,
 1347     struct timespec *tsp, sigset_t *uset)
 1348 {
 1349         struct pollfd *bits;
 1350         struct pollfd smallbits[32];
 1351         sbintime_t sbt, precision, tmp;
 1352         time_t over;
 1353         struct timespec ts;
 1354         int error;
 1355         size_t ni;
 1356 
 1357         precision = 0;
 1358         if (tsp != NULL) {
 1359                 if (tsp->tv_sec < 0)
 1360                         return (EINVAL);
 1361                 if (tsp->tv_nsec < 0 || tsp->tv_nsec >= 1000000000)
 1362                         return (EINVAL);
 1363                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
 1364                         sbt = 0;
 1365                 else {
 1366                         ts = *tsp;
 1367                         if (ts.tv_sec > INT32_MAX / 2) {
 1368                                 over = ts.tv_sec - INT32_MAX / 2;
 1369                                 ts.tv_sec -= over;
 1370                         } else
 1371                                 over = 0;
 1372                         tmp = tstosbt(ts);
 1373                         precision = tmp;
 1374                         precision >>= tc_precexp;
 1375                         if (TIMESEL(&sbt, tmp))
 1376                                 sbt += tc_tick_sbt;
 1377                         sbt += tmp;
 1378                 }
 1379         } else
 1380                 sbt = -1;
 1381 
 1382         if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 
 1383                 return (EINVAL);
 1384         ni = nfds * sizeof(struct pollfd);
 1385         if (ni > sizeof(smallbits))
 1386                 bits = malloc(ni, M_TEMP, M_WAITOK);
 1387         else
 1388                 bits = smallbits;
 1389         error = copyin(fds, bits, ni);
 1390         if (error)
 1391                 goto done;
 1392 
 1393         if (uset != NULL) {
 1394                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
 1395                     &td->td_oldsigmask, 0);
 1396                 if (error)
 1397                         goto done;
 1398                 td->td_pflags |= TDP_OLDMASK;
 1399                 /*
 1400                  * Make sure that ast() is called on return to
 1401                  * usermode and TDP_OLDMASK is cleared, restoring old
 1402                  * sigmask.
 1403                  */
 1404                 thread_lock(td);
 1405                 td->td_flags |= TDF_ASTPENDING;
 1406                 thread_unlock(td);
 1407         }
 1408 
 1409         seltdinit(td);
 1410         /* Iterate until the timeout expires or descriptors become ready. */
 1411         for (;;) {
 1412                 error = pollscan(td, bits, nfds);
 1413                 if (error || td->td_retval[0] != 0)
 1414                         break;
 1415                 error = seltdwait(td, sbt, precision);
 1416                 if (error)
 1417                         break;
 1418                 error = pollrescan(td);
 1419                 if (error || td->td_retval[0] != 0)
 1420                         break;
 1421         }
 1422         seltdclear(td);
 1423 
 1424 done:
 1425         /* poll is not restarted after signals... */
 1426         if (error == ERESTART)
 1427                 error = EINTR;
 1428         if (error == EWOULDBLOCK)
 1429                 error = 0;
 1430         if (error == 0) {
 1431                 error = pollout(td, bits, fds, nfds);
 1432                 if (error)
 1433                         goto out;
 1434         }
 1435 out:
 1436         if (ni > sizeof(smallbits))
 1437                 free(bits, M_TEMP);
 1438         return (error);
 1439 }
 1440 
 1441 int
 1442 sys_ppoll(struct thread *td, struct ppoll_args *uap)
 1443 {
 1444         struct timespec ts, *tsp;
 1445         sigset_t set, *ssp;
 1446         int error;
 1447 
 1448         if (uap->ts != NULL) {
 1449                 error = copyin(uap->ts, &ts, sizeof(ts));
 1450                 if (error)
 1451                         return (error);
 1452                 tsp = &ts;
 1453         } else
 1454                 tsp = NULL;
 1455         if (uap->set != NULL) {
 1456                 error = copyin(uap->set, &set, sizeof(set));
 1457                 if (error)
 1458                         return (error);
 1459                 ssp = &set;
 1460         } else
 1461                 ssp = NULL;
 1462         /*
 1463          * fds is still a pointer to user space. kern_poll() will
 1464          * take care of copyin that array to the kernel space.
 1465          */
 1466 
 1467         return (kern_poll(td, uap->fds, uap->nfds, tsp, ssp));
 1468 }
 1469 
 1470 static int
 1471 pollrescan(struct thread *td)
 1472 {
 1473         struct seltd *stp;
 1474         struct selfd *sfp;
 1475         struct selfd *sfn;
 1476         struct selinfo *si;
 1477         struct filedesc *fdp;
 1478         struct file *fp;
 1479         struct pollfd *fd;
 1480 #ifdef CAPABILITIES
 1481         cap_rights_t rights;
 1482 #endif
 1483         int n;
 1484 
 1485         n = 0;
 1486         fdp = td->td_proc->p_fd;
 1487         stp = td->td_sel;
 1488         FILEDESC_SLOCK(fdp);
 1489         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1490                 fd = (struct pollfd *)sfp->sf_cookie;
 1491                 si = sfp->sf_si;
 1492                 selfdfree(stp, sfp);
 1493                 /* If the selinfo wasn't cleared the event didn't fire. */
 1494                 if (si != NULL)
 1495                         continue;
 1496                 fp = fdp->fd_ofiles[fd->fd].fde_file;
 1497 #ifdef CAPABILITIES
 1498                 if (fp == NULL ||
 1499                     cap_check(cap_rights(fdp, fd->fd),
 1500                     cap_rights_init(&rights, CAP_EVENT)) != 0)
 1501 #else
 1502                 if (fp == NULL)
 1503 #endif
 1504                 {
 1505                         fd->revents = POLLNVAL;
 1506                         n++;
 1507                         continue;
 1508                 }
 1509 
 1510                 /*
 1511                  * Note: backend also returns POLLHUP and
 1512                  * POLLERR if appropriate.
 1513                  */
 1514                 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
 1515                 if (fd->revents != 0)
 1516                         n++;
 1517         }
 1518         FILEDESC_SUNLOCK(fdp);
 1519         stp->st_flags = 0;
 1520         td->td_retval[0] = n;
 1521         return (0);
 1522 }
 1523 
 1524 
 1525 static int
 1526 pollout(td, fds, ufds, nfd)
 1527         struct thread *td;
 1528         struct pollfd *fds;
 1529         struct pollfd *ufds;
 1530         u_int nfd;
 1531 {
 1532         int error = 0;
 1533         u_int i = 0;
 1534         u_int n = 0;
 1535 
 1536         for (i = 0; i < nfd; i++) {
 1537                 error = copyout(&fds->revents, &ufds->revents,
 1538                     sizeof(ufds->revents));
 1539                 if (error)
 1540                         return (error);
 1541                 if (fds->revents != 0)
 1542                         n++;
 1543                 fds++;
 1544                 ufds++;
 1545         }
 1546         td->td_retval[0] = n;
 1547         return (0);
 1548 }
 1549 
 1550 static int
 1551 pollscan(td, fds, nfd)
 1552         struct thread *td;
 1553         struct pollfd *fds;
 1554         u_int nfd;
 1555 {
 1556         struct filedesc *fdp = td->td_proc->p_fd;
 1557         struct file *fp;
 1558 #ifdef CAPABILITIES
 1559         cap_rights_t rights;
 1560 #endif
 1561         int i, n = 0;
 1562 
 1563         FILEDESC_SLOCK(fdp);
 1564         for (i = 0; i < nfd; i++, fds++) {
 1565                 if (fds->fd > fdp->fd_lastfile) {
 1566                         fds->revents = POLLNVAL;
 1567                         n++;
 1568                 } else if (fds->fd < 0) {
 1569                         fds->revents = 0;
 1570                 } else {
 1571                         fp = fdp->fd_ofiles[fds->fd].fde_file;
 1572 #ifdef CAPABILITIES
 1573                         if (fp == NULL ||
 1574                             cap_check(cap_rights(fdp, fds->fd),
 1575                             cap_rights_init(&rights, CAP_EVENT)) != 0)
 1576 #else
 1577                         if (fp == NULL)
 1578 #endif
 1579                         {
 1580                                 fds->revents = POLLNVAL;
 1581                                 n++;
 1582                         } else {
 1583                                 /*
 1584                                  * Note: backend also returns POLLHUP and
 1585                                  * POLLERR if appropriate.
 1586                                  */
 1587                                 selfdalloc(td, fds);
 1588                                 fds->revents = fo_poll(fp, fds->events,
 1589                                     td->td_ucred, td);
 1590                                 /*
 1591                                  * POSIX requires POLLOUT to be never
 1592                                  * set simultaneously with POLLHUP.
 1593                                  */
 1594                                 if ((fds->revents & POLLHUP) != 0)
 1595                                         fds->revents &= ~POLLOUT;
 1596 
 1597                                 if (fds->revents != 0)
 1598                                         n++;
 1599                         }
 1600                 }
 1601         }
 1602         FILEDESC_SUNLOCK(fdp);
 1603         td->td_retval[0] = n;
 1604         return (0);
 1605 }
 1606 
 1607 /*
 1608  * OpenBSD poll system call.
 1609  *
 1610  * XXX this isn't quite a true representation..  OpenBSD uses select ops.
 1611  */
 1612 #ifndef _SYS_SYSPROTO_H_
 1613 struct openbsd_poll_args {
 1614         struct pollfd *fds;
 1615         u_int   nfds;
 1616         int     timeout;
 1617 };
 1618 #endif
 1619 int
 1620 sys_openbsd_poll(td, uap)
 1621         register struct thread *td;
 1622         register struct openbsd_poll_args *uap;
 1623 {
 1624         return (sys_poll(td, (struct poll_args *)uap));
 1625 }
 1626 
 1627 /*
 1628  * XXX This was created specifically to support netncp and netsmb.  This
 1629  * allows the caller to specify a socket to wait for events on.  It returns
 1630  * 0 if any events matched and an error otherwise.  There is no way to
 1631  * determine which events fired.
 1632  */
 1633 int
 1634 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
 1635 {
 1636         struct timeval rtv;
 1637         sbintime_t asbt, precision, rsbt;
 1638         int error;
 1639 
 1640         precision = 0;  /* stupid gcc! */
 1641         if (tvp != NULL) {
 1642                 rtv = *tvp;
 1643                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 || 
 1644                     rtv.tv_usec >= 1000000)
 1645                         return (EINVAL);
 1646                 if (!timevalisset(&rtv))
 1647                         asbt = 0;
 1648                 else if (rtv.tv_sec <= INT32_MAX) {
 1649                         rsbt = tvtosbt(rtv);
 1650                         precision = rsbt;
 1651                         precision >>= tc_precexp;
 1652                         if (TIMESEL(&asbt, rsbt))
 1653                                 asbt += tc_tick_sbt;
 1654                         if (asbt <= SBT_MAX - rsbt)
 1655                                 asbt += rsbt;
 1656                         else
 1657                                 asbt = -1;
 1658                 } else
 1659                         asbt = -1;
 1660         } else
 1661                 asbt = -1;
 1662         seltdinit(td);
 1663         /*
 1664          * Iterate until the timeout expires or the socket becomes ready.
 1665          */
 1666         for (;;) {
 1667                 selfdalloc(td, NULL);
 1668                 error = sopoll(so, events, NULL, td);
 1669                 /* error here is actually the ready events. */
 1670                 if (error)
 1671                         return (0);
 1672                 error = seltdwait(td, asbt, precision);
 1673                 if (error)
 1674                         break;
 1675         }
 1676         seltdclear(td);
 1677         /* XXX Duplicates ncp/smb behavior. */
 1678         if (error == ERESTART)
 1679                 error = 0;
 1680         return (error);
 1681 }
 1682 
 1683 /*
 1684  * Preallocate two selfds associated with 'cookie'.  Some fo_poll routines
 1685  * have two select sets, one for read and another for write.
 1686  */
 1687 static void
 1688 selfdalloc(struct thread *td, void *cookie)
 1689 {
 1690         struct seltd *stp;
 1691 
 1692         stp = td->td_sel;
 1693         if (stp->st_free1 == NULL)
 1694                 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1695         stp->st_free1->sf_td = stp;
 1696         stp->st_free1->sf_cookie = cookie;
 1697         if (stp->st_free2 == NULL)
 1698                 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1699         stp->st_free2->sf_td = stp;
 1700         stp->st_free2->sf_cookie = cookie;
 1701 }
 1702 
 1703 static void
 1704 selfdfree(struct seltd *stp, struct selfd *sfp)
 1705 {
 1706         STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
 1707         if (sfp->sf_si != NULL) {
 1708                 mtx_lock(sfp->sf_mtx);
 1709                 if (sfp->sf_si != NULL) {
 1710                         TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
 1711                         refcount_release(&sfp->sf_refs);
 1712                 }
 1713                 mtx_unlock(sfp->sf_mtx);
 1714         }
 1715         if (refcount_release(&sfp->sf_refs))
 1716                 uma_zfree(selfd_zone, sfp);
 1717 }
 1718 
 1719 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */
 1720 void
 1721 seldrain(sip)
 1722         struct selinfo *sip;
 1723 {
 1724 
 1725         /*
 1726          * This feature is already provided by doselwakeup(), thus it is
 1727          * enough to go for it.
 1728          * Eventually, the context, should take care to avoid races
 1729          * between thread calling select()/poll() and file descriptor
 1730          * detaching, but, again, the races are just the same as
 1731          * selwakeup().
 1732          */
 1733         doselwakeup(sip, -1);
 1734 }
 1735 
 1736 /*
 1737  * Record a select request.
 1738  */
 1739 void
 1740 selrecord(selector, sip)
 1741         struct thread *selector;
 1742         struct selinfo *sip;
 1743 {
 1744         struct selfd *sfp;
 1745         struct seltd *stp;
 1746         struct mtx *mtxp;
 1747 
 1748         stp = selector->td_sel;
 1749         /*
 1750          * Don't record when doing a rescan.
 1751          */
 1752         if (stp->st_flags & SELTD_RESCAN)
 1753                 return;
 1754         /*
 1755          * Grab one of the preallocated descriptors.
 1756          */
 1757         sfp = NULL;
 1758         if ((sfp = stp->st_free1) != NULL)
 1759                 stp->st_free1 = NULL;
 1760         else if ((sfp = stp->st_free2) != NULL)
 1761                 stp->st_free2 = NULL;
 1762         else
 1763                 panic("selrecord: No free selfd on selq");
 1764         mtxp = sip->si_mtx;
 1765         if (mtxp == NULL)
 1766                 mtxp = mtx_pool_find(mtxpool_select, sip);
 1767         /*
 1768          * Initialize the sfp and queue it in the thread.
 1769          */
 1770         sfp->sf_si = sip;
 1771         sfp->sf_mtx = mtxp;
 1772         refcount_init(&sfp->sf_refs, 2);
 1773         STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
 1774         /*
 1775          * Now that we've locked the sip, check for initialization.
 1776          */
 1777         mtx_lock(mtxp);
 1778         if (sip->si_mtx == NULL) {
 1779                 sip->si_mtx = mtxp;
 1780                 TAILQ_INIT(&sip->si_tdlist);
 1781         }
 1782         /*
 1783          * Add this thread to the list of selfds listening on this selinfo.
 1784          */
 1785         TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
 1786         mtx_unlock(sip->si_mtx);
 1787 }
 1788 
 1789 /* Wake up a selecting thread. */
 1790 void
 1791 selwakeup(sip)
 1792         struct selinfo *sip;
 1793 {
 1794         doselwakeup(sip, -1);
 1795 }
 1796 
 1797 /* Wake up a selecting thread, and set its priority. */
 1798 void
 1799 selwakeuppri(sip, pri)
 1800         struct selinfo *sip;
 1801         int pri;
 1802 {
 1803         doselwakeup(sip, pri);
 1804 }
 1805 
 1806 /*
 1807  * Do a wakeup when a selectable event occurs.
 1808  */
 1809 static void
 1810 doselwakeup(sip, pri)
 1811         struct selinfo *sip;
 1812         int pri;
 1813 {
 1814         struct selfd *sfp;
 1815         struct selfd *sfn;
 1816         struct seltd *stp;
 1817 
 1818         /* If it's not initialized there can't be any waiters. */
 1819         if (sip->si_mtx == NULL)
 1820                 return;
 1821         /*
 1822          * Locking the selinfo locks all selfds associated with it.
 1823          */
 1824         mtx_lock(sip->si_mtx);
 1825         TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
 1826                 /*
 1827                  * Once we remove this sfp from the list and clear the
 1828                  * sf_si seltdclear will know to ignore this si.
 1829                  */
 1830                 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
 1831                 sfp->sf_si = NULL;
 1832                 stp = sfp->sf_td;
 1833                 mtx_lock(&stp->st_mtx);
 1834                 stp->st_flags |= SELTD_PENDING;
 1835                 cv_broadcastpri(&stp->st_wait, pri);
 1836                 mtx_unlock(&stp->st_mtx);
 1837                 if (refcount_release(&sfp->sf_refs))
 1838                         uma_zfree(selfd_zone, sfp);
 1839         }
 1840         mtx_unlock(sip->si_mtx);
 1841 }
 1842 
 1843 static void
 1844 seltdinit(struct thread *td)
 1845 {
 1846         struct seltd *stp;
 1847 
 1848         if ((stp = td->td_sel) != NULL)
 1849                 goto out;
 1850         td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
 1851         mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
 1852         cv_init(&stp->st_wait, "select");
 1853 out:
 1854         stp->st_flags = 0;
 1855         STAILQ_INIT(&stp->st_selq);
 1856 }
 1857 
 1858 static int
 1859 seltdwait(struct thread *td, sbintime_t sbt, sbintime_t precision)
 1860 {
 1861         struct seltd *stp;
 1862         int error;
 1863 
 1864         stp = td->td_sel;
 1865         /*
 1866          * An event of interest may occur while we do not hold the seltd
 1867          * locked so check the pending flag before we sleep.
 1868          */
 1869         mtx_lock(&stp->st_mtx);
 1870         /*
 1871          * Any further calls to selrecord will be a rescan.
 1872          */
 1873         stp->st_flags |= SELTD_RESCAN;
 1874         if (stp->st_flags & SELTD_PENDING) {
 1875                 mtx_unlock(&stp->st_mtx);
 1876                 return (0);
 1877         }
 1878         if (sbt == 0)
 1879                 error = EWOULDBLOCK;
 1880         else if (sbt != -1)
 1881                 error = cv_timedwait_sig_sbt(&stp->st_wait, &stp->st_mtx,
 1882                     sbt, precision, C_ABSOLUTE);
 1883         else
 1884                 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
 1885         mtx_unlock(&stp->st_mtx);
 1886 
 1887         return (error);
 1888 }
 1889 
 1890 void
 1891 seltdfini(struct thread *td)
 1892 {
 1893         struct seltd *stp;
 1894 
 1895         stp = td->td_sel;
 1896         if (stp == NULL)
 1897                 return;
 1898         if (stp->st_free1)
 1899                 uma_zfree(selfd_zone, stp->st_free1);
 1900         if (stp->st_free2)
 1901                 uma_zfree(selfd_zone, stp->st_free2);
 1902         td->td_sel = NULL;
 1903         free(stp, M_SELECT);
 1904 }
 1905 
 1906 /*
 1907  * Remove the references to the thread from all of the objects we were
 1908  * polling.
 1909  */
 1910 static void
 1911 seltdclear(struct thread *td)
 1912 {
 1913         struct seltd *stp;
 1914         struct selfd *sfp;
 1915         struct selfd *sfn;
 1916 
 1917         stp = td->td_sel;
 1918         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
 1919                 selfdfree(stp, sfp);
 1920         stp->st_flags = 0;
 1921 }
 1922 
 1923 static void selectinit(void *);
 1924 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
 1925 static void
 1926 selectinit(void *dummy __unused)
 1927 {
 1928 
 1929         selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
 1930             NULL, NULL, UMA_ALIGN_PTR, 0);
 1931         mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
 1932 }
 1933 
 1934 /*
 1935  * Set up a syscall return value that follows the convention specified for
 1936  * posix_* functions.
 1937  */
 1938 int
 1939 kern_posix_error(struct thread *td, int error)
 1940 {
 1941 
 1942         if (error <= 0)
 1943                 return (error);
 1944         td->td_errno = error;
 1945         td->td_pflags |= TDP_NERRNO;
 1946         td->td_retval[0] = error;
 1947         return (0);
 1948 }

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