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


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

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1989, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)sys_generic.c       8.5 (Berkeley) 1/21/94
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD: stable/10/sys/kern/sys_generic.c 360332 2020-04-26 08:35:32Z hselasky $");
   39 
   40 #include "opt_capsicum.h"
   41 #include "opt_compat.h"
   42 #include "opt_ktrace.h"
   43 
   44 #include <sys/param.h>
   45 #include <sys/systm.h>
   46 #include <sys/sysproto.h>
   47 #include <sys/capsicum.h>
   48 #include <sys/filedesc.h>
   49 #include <sys/filio.h>
   50 #include <sys/fcntl.h>
   51 #include <sys/file.h>
   52 #include <sys/lock.h>
   53 #include <sys/proc.h>
   54 #include <sys/signalvar.h>
   55 #include <sys/socketvar.h>
   56 #include <sys/uio.h>
   57 #include <sys/kernel.h>
   58 #include <sys/ktr.h>
   59 #include <sys/limits.h>
   60 #include <sys/malloc.h>
   61 #include <sys/poll.h>
   62 #include <sys/resourcevar.h>
   63 #include <sys/selinfo.h>
   64 #include <sys/sleepqueue.h>
   65 #include <sys/syscallsubr.h>
   66 #include <sys/sysctl.h>
   67 #include <sys/sysent.h>
   68 #include <sys/vnode.h>
   69 #include <sys/bio.h>
   70 #include <sys/buf.h>
   71 #include <sys/condvar.h>
   72 #ifdef KTRACE
   73 #include <sys/ktrace.h>
   74 #endif
   75 
   76 #include <security/audit/audit.h>
   77 
   78 /*
   79  * The following macro defines how many bytes will be allocated from
   80  * the stack instead of memory allocated when passing the IOCTL data
   81  * structures from userspace and to the kernel. Some IOCTLs having
   82  * small data structures are used very frequently and this small
   83  * buffer on the stack gives a significant speedup improvement for
   84  * those requests. The value of this define should be greater or equal
   85  * to 64 bytes and should also be power of two. The data structure is
   86  * currently hard-aligned to a 8-byte boundary on the stack. This
   87  * should currently be sufficient for all supported platforms.
   88  */
   89 #define SYS_IOCTL_SMALL_SIZE    128     /* bytes */
   90 #define SYS_IOCTL_SMALL_ALIGN   8       /* bytes */
   91 
   92 int iosize_max_clamp = 1;
   93 SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW,
   94     &iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX");
   95 int devfs_iosize_max_clamp = 1;
   96 SYSCTL_INT(_debug, OID_AUTO, devfs_iosize_max_clamp, CTLFLAG_RW,
   97     &devfs_iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX for devices");
   98 
   99 /*
  100  * Assert that the return value of read(2) and write(2) syscalls fits
  101  * into a register.  If not, an architecture will need to provide the
  102  * usermode wrappers to reconstruct the result.
  103  */
  104 CTASSERT(sizeof(register_t) >= sizeof(size_t));
  105 
  106 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer");
  107 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer");
  108 MALLOC_DEFINE(M_IOV, "iov", "large iov's");
  109 
  110 static int      pollout(struct thread *, struct pollfd *, struct pollfd *,
  111                     u_int);
  112 static int      pollscan(struct thread *, struct pollfd *, u_int);
  113 static int      pollrescan(struct thread *);
  114 static int      selscan(struct thread *, fd_mask **, fd_mask **, int);
  115 static int      selrescan(struct thread *, fd_mask **, fd_mask **);
  116 static void     selfdalloc(struct thread *, void *);
  117 static void     selfdfree(struct seltd *, struct selfd *);
  118 static int      dofileread(struct thread *, int, struct file *, struct uio *,
  119                     off_t, int);
  120 static int      dofilewrite(struct thread *, int, struct file *, struct uio *,
  121                     off_t, int);
  122 static void     doselwakeup(struct selinfo *, int);
  123 static void     seltdinit(struct thread *);
  124 static int      seltdwait(struct thread *, sbintime_t, sbintime_t);
  125 static void     seltdclear(struct thread *);
  126 
  127 /*
  128  * One seltd per-thread allocated on demand as needed.
  129  *
  130  *      t - protected by st_mtx
  131  *      k - Only accessed by curthread or read-only
  132  */
  133 struct seltd {
  134         STAILQ_HEAD(, selfd)    st_selq;        /* (k) List of selfds. */
  135         struct selfd            *st_free1;      /* (k) free fd for read set. */
  136         struct selfd            *st_free2;      /* (k) free fd for write set. */
  137         struct mtx              st_mtx;         /* Protects struct seltd */
  138         struct cv               st_wait;        /* (t) Wait channel. */
  139         int                     st_flags;       /* (t) SELTD_ flags. */
  140 };
  141 
  142 #define SELTD_PENDING   0x0001                  /* We have pending events. */
  143 #define SELTD_RESCAN    0x0002                  /* Doing a rescan. */
  144 
  145 /*
  146  * One selfd allocated per-thread per-file-descriptor.
  147  *      f - protected by sf_mtx
  148  */
  149 struct selfd {
  150         STAILQ_ENTRY(selfd)     sf_link;        /* (k) fds owned by this td. */
  151         TAILQ_ENTRY(selfd)      sf_threads;     /* (f) fds on this selinfo. */
  152         struct selinfo          *sf_si;         /* (f) selinfo when linked. */
  153         struct mtx              *sf_mtx;        /* Pointer to selinfo mtx. */
  154         struct seltd            *sf_td;         /* (k) owning seltd. */
  155         void                    *sf_cookie;     /* (k) fd or pollfd. */
  156 };
  157 
  158 static uma_zone_t selfd_zone;
  159 static struct mtx_pool *mtxpool_select;
  160 
  161 #ifndef _SYS_SYSPROTO_H_
  162 struct read_args {
  163         int     fd;
  164         void    *buf;
  165         size_t  nbyte;
  166 };
  167 #endif
  168 int
  169 sys_read(td, uap)
  170         struct thread *td;
  171         struct read_args *uap;
  172 {
  173         struct uio auio;
  174         struct iovec aiov;
  175         int error;
  176 
  177         if (uap->nbyte > IOSIZE_MAX)
  178                 return (EINVAL);
  179         aiov.iov_base = uap->buf;
  180         aiov.iov_len = uap->nbyte;
  181         auio.uio_iov = &aiov;
  182         auio.uio_iovcnt = 1;
  183         auio.uio_resid = uap->nbyte;
  184         auio.uio_segflg = UIO_USERSPACE;
  185         error = kern_readv(td, uap->fd, &auio);
  186         return(error);
  187 }
  188 
  189 /*
  190  * Positioned read system call
  191  */
  192 #ifndef _SYS_SYSPROTO_H_
  193 struct pread_args {
  194         int     fd;
  195         void    *buf;
  196         size_t  nbyte;
  197         int     pad;
  198         off_t   offset;
  199 };
  200 #endif
  201 int
  202 sys_pread(td, uap)
  203         struct thread *td;
  204         struct pread_args *uap;
  205 {
  206         struct uio auio;
  207         struct iovec aiov;
  208         int error;
  209 
  210         if (uap->nbyte > IOSIZE_MAX)
  211                 return (EINVAL);
  212         aiov.iov_base = uap->buf;
  213         aiov.iov_len = uap->nbyte;
  214         auio.uio_iov = &aiov;
  215         auio.uio_iovcnt = 1;
  216         auio.uio_resid = uap->nbyte;
  217         auio.uio_segflg = UIO_USERSPACE;
  218         error = kern_preadv(td, uap->fd, &auio, uap->offset);
  219         return(error);
  220 }
  221 
  222 int
  223 freebsd6_pread(td, uap)
  224         struct thread *td;
  225         struct freebsd6_pread_args *uap;
  226 {
  227         struct pread_args oargs;
  228 
  229         oargs.fd = uap->fd;
  230         oargs.buf = uap->buf;
  231         oargs.nbyte = uap->nbyte;
  232         oargs.offset = uap->offset;
  233         return (sys_pread(td, &oargs));
  234 }
  235 
  236 /*
  237  * Scatter read system call.
  238  */
  239 #ifndef _SYS_SYSPROTO_H_
  240 struct readv_args {
  241         int     fd;
  242         struct  iovec *iovp;
  243         u_int   iovcnt;
  244 };
  245 #endif
  246 int
  247 sys_readv(struct thread *td, struct readv_args *uap)
  248 {
  249         struct uio *auio;
  250         int error;
  251 
  252         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  253         if (error)
  254                 return (error);
  255         error = kern_readv(td, uap->fd, auio);
  256         free(auio, M_IOV);
  257         return (error);
  258 }
  259 
  260 int
  261 kern_readv(struct thread *td, int fd, struct uio *auio)
  262 {
  263         struct file *fp;
  264         cap_rights_t rights;
  265         int error;
  266 
  267         error = fget_read(td, fd, cap_rights_init(&rights, CAP_READ), &fp);
  268         if (error)
  269                 return (error);
  270         error = dofileread(td, fd, fp, auio, (off_t)-1, 0);
  271         fdrop(fp, td);
  272         return (error);
  273 }
  274 
  275 /*
  276  * Scatter positioned read system call.
  277  */
  278 #ifndef _SYS_SYSPROTO_H_
  279 struct preadv_args {
  280         int     fd;
  281         struct  iovec *iovp;
  282         u_int   iovcnt;
  283         off_t   offset;
  284 };
  285 #endif
  286 int
  287 sys_preadv(struct thread *td, struct preadv_args *uap)
  288 {
  289         struct uio *auio;
  290         int error;
  291 
  292         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  293         if (error)
  294                 return (error);
  295         error = kern_preadv(td, uap->fd, auio, uap->offset);
  296         free(auio, M_IOV);
  297         return (error);
  298 }
  299 
  300 int
  301 kern_preadv(td, fd, auio, offset)
  302         struct thread *td;
  303         int fd;
  304         struct uio *auio;
  305         off_t offset;
  306 {
  307         struct file *fp;
  308         cap_rights_t rights;
  309         int error;
  310 
  311         error = fget_read(td, fd, cap_rights_init(&rights, CAP_PREAD), &fp);
  312         if (error)
  313                 return (error);
  314         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  315                 error = ESPIPE;
  316         else if (offset < 0 &&
  317             (fp->f_vnode == NULL || fp->f_vnode->v_type != VCHR))
  318                 error = EINVAL;
  319         else
  320                 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET);
  321         fdrop(fp, td);
  322         return (error);
  323 }
  324 
  325 /*
  326  * Common code for readv and preadv that reads data in
  327  * from a file using the passed in uio, offset, and flags.
  328  */
  329 static int
  330 dofileread(td, fd, fp, auio, offset, flags)
  331         struct thread *td;
  332         int fd;
  333         struct file *fp;
  334         struct uio *auio;
  335         off_t offset;
  336         int flags;
  337 {
  338         ssize_t cnt;
  339         int error;
  340 #ifdef KTRACE
  341         struct uio *ktruio = NULL;
  342 #endif
  343 
  344         /* Finish zero length reads right here */
  345         if (auio->uio_resid == 0) {
  346                 td->td_retval[0] = 0;
  347                 return(0);
  348         }
  349         auio->uio_rw = UIO_READ;
  350         auio->uio_offset = offset;
  351         auio->uio_td = td;
  352 #ifdef KTRACE
  353         if (KTRPOINT(td, KTR_GENIO)) 
  354                 ktruio = cloneuio(auio);
  355 #endif
  356         cnt = auio->uio_resid;
  357         if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) {
  358                 if (auio->uio_resid != cnt && (error == ERESTART ||
  359                     error == EINTR || error == EWOULDBLOCK))
  360                         error = 0;
  361         }
  362         cnt -= auio->uio_resid;
  363 #ifdef KTRACE
  364         if (ktruio != NULL) {
  365                 ktruio->uio_resid = cnt;
  366                 ktrgenio(fd, UIO_READ, ktruio, error);
  367         }
  368 #endif
  369         td->td_retval[0] = cnt;
  370         return (error);
  371 }
  372 
  373 #ifndef _SYS_SYSPROTO_H_
  374 struct write_args {
  375         int     fd;
  376         const void *buf;
  377         size_t  nbyte;
  378 };
  379 #endif
  380 int
  381 sys_write(td, uap)
  382         struct thread *td;
  383         struct write_args *uap;
  384 {
  385         struct uio auio;
  386         struct iovec aiov;
  387         int error;
  388 
  389         if (uap->nbyte > IOSIZE_MAX)
  390                 return (EINVAL);
  391         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  392         aiov.iov_len = uap->nbyte;
  393         auio.uio_iov = &aiov;
  394         auio.uio_iovcnt = 1;
  395         auio.uio_resid = uap->nbyte;
  396         auio.uio_segflg = UIO_USERSPACE;
  397         error = kern_writev(td, uap->fd, &auio);
  398         return(error);
  399 }
  400 
  401 /*
  402  * Positioned write system call.
  403  */
  404 #ifndef _SYS_SYSPROTO_H_
  405 struct pwrite_args {
  406         int     fd;
  407         const void *buf;
  408         size_t  nbyte;
  409         int     pad;
  410         off_t   offset;
  411 };
  412 #endif
  413 int
  414 sys_pwrite(td, uap)
  415         struct thread *td;
  416         struct pwrite_args *uap;
  417 {
  418         struct uio auio;
  419         struct iovec aiov;
  420         int error;
  421 
  422         if (uap->nbyte > IOSIZE_MAX)
  423                 return (EINVAL);
  424         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  425         aiov.iov_len = uap->nbyte;
  426         auio.uio_iov = &aiov;
  427         auio.uio_iovcnt = 1;
  428         auio.uio_resid = uap->nbyte;
  429         auio.uio_segflg = UIO_USERSPACE;
  430         error = kern_pwritev(td, uap->fd, &auio, uap->offset);
  431         return(error);
  432 }
  433 
  434 int
  435 freebsd6_pwrite(td, uap)
  436         struct thread *td;
  437         struct freebsd6_pwrite_args *uap;
  438 {
  439         struct pwrite_args oargs;
  440 
  441         oargs.fd = uap->fd;
  442         oargs.buf = uap->buf;
  443         oargs.nbyte = uap->nbyte;
  444         oargs.offset = uap->offset;
  445         return (sys_pwrite(td, &oargs));
  446 }
  447 
  448 /*
  449  * Gather write system call.
  450  */
  451 #ifndef _SYS_SYSPROTO_H_
  452 struct writev_args {
  453         int     fd;
  454         struct  iovec *iovp;
  455         u_int   iovcnt;
  456 };
  457 #endif
  458 int
  459 sys_writev(struct thread *td, struct writev_args *uap)
  460 {
  461         struct uio *auio;
  462         int error;
  463 
  464         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  465         if (error)
  466                 return (error);
  467         error = kern_writev(td, uap->fd, auio);
  468         free(auio, M_IOV);
  469         return (error);
  470 }
  471 
  472 int
  473 kern_writev(struct thread *td, int fd, struct uio *auio)
  474 {
  475         struct file *fp;
  476         cap_rights_t rights;
  477         int error;
  478 
  479         error = fget_write(td, fd, cap_rights_init(&rights, CAP_WRITE), &fp);
  480         if (error)
  481                 return (error);
  482         error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0);
  483         fdrop(fp, td);
  484         return (error);
  485 }
  486 
  487 /*
  488  * Gather positioned write system call.
  489  */
  490 #ifndef _SYS_SYSPROTO_H_
  491 struct pwritev_args {
  492         int     fd;
  493         struct  iovec *iovp;
  494         u_int   iovcnt;
  495         off_t   offset;
  496 };
  497 #endif
  498 int
  499 sys_pwritev(struct thread *td, struct pwritev_args *uap)
  500 {
  501         struct uio *auio;
  502         int error;
  503 
  504         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  505         if (error)
  506                 return (error);
  507         error = kern_pwritev(td, uap->fd, auio, uap->offset);
  508         free(auio, M_IOV);
  509         return (error);
  510 }
  511 
  512 int
  513 kern_pwritev(td, fd, auio, offset)
  514         struct thread *td;
  515         struct uio *auio;
  516         int fd;
  517         off_t offset;
  518 {
  519         struct file *fp;
  520         cap_rights_t rights;
  521         int error;
  522 
  523         error = fget_write(td, fd, cap_rights_init(&rights, CAP_PWRITE), &fp);
  524         if (error)
  525                 return (error);
  526         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  527                 error = ESPIPE;
  528         else if (offset < 0 &&
  529             (fp->f_vnode == NULL || fp->f_vnode->v_type != VCHR))
  530                 error = EINVAL;
  531         else
  532                 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET);
  533         fdrop(fp, td);
  534         return (error);
  535 }
  536 
  537 /*
  538  * Common code for writev and pwritev that writes data to
  539  * a file using the passed in uio, offset, and flags.
  540  */
  541 static int
  542 dofilewrite(td, fd, fp, auio, offset, flags)
  543         struct thread *td;
  544         int fd;
  545         struct file *fp;
  546         struct uio *auio;
  547         off_t offset;
  548         int flags;
  549 {
  550         ssize_t cnt;
  551         int error;
  552 #ifdef KTRACE
  553         struct uio *ktruio = NULL;
  554 #endif
  555 
  556         auio->uio_rw = UIO_WRITE;
  557         auio->uio_td = td;
  558         auio->uio_offset = offset;
  559 #ifdef KTRACE
  560         if (KTRPOINT(td, KTR_GENIO))
  561                 ktruio = cloneuio(auio);
  562 #endif
  563         cnt = auio->uio_resid;
  564         if (fp->f_type == DTYPE_VNODE &&
  565             (fp->f_vnread_flags & FDEVFS_VNODE) == 0)
  566                 bwillwrite();
  567         if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) {
  568                 if (auio->uio_resid != cnt && (error == ERESTART ||
  569                     error == EINTR || error == EWOULDBLOCK))
  570                         error = 0;
  571                 /* Socket layer is responsible for issuing SIGPIPE. */
  572                 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) {
  573                         PROC_LOCK(td->td_proc);
  574                         tdsignal(td, SIGPIPE);
  575                         PROC_UNLOCK(td->td_proc);
  576                 }
  577         }
  578         cnt -= auio->uio_resid;
  579 #ifdef KTRACE
  580         if (ktruio != NULL) {
  581                 ktruio->uio_resid = cnt;
  582                 ktrgenio(fd, UIO_WRITE, ktruio, error);
  583         }
  584 #endif
  585         td->td_retval[0] = cnt;
  586         return (error);
  587 }
  588 
  589 /*
  590  * Truncate a file given a file descriptor.
  591  *
  592  * Can't use fget_write() here, since must return EINVAL and not EBADF if the
  593  * descriptor isn't writable.
  594  */
  595 int
  596 kern_ftruncate(td, fd, length)
  597         struct thread *td;
  598         int fd;
  599         off_t length;
  600 {
  601         struct file *fp;
  602         cap_rights_t rights;
  603         int error;
  604 
  605         AUDIT_ARG_FD(fd);
  606         if (length < 0)
  607                 return (EINVAL);
  608         error = fget(td, fd, cap_rights_init(&rights, CAP_FTRUNCATE), &fp);
  609         if (error)
  610                 return (error);
  611         AUDIT_ARG_FILE(td->td_proc, fp);
  612         if (!(fp->f_flag & FWRITE)) {
  613                 fdrop(fp, td);
  614                 return (EINVAL);
  615         }
  616         error = fo_truncate(fp, length, td->td_ucred, td);
  617         fdrop(fp, td);
  618         return (error);
  619 }
  620 
  621 #ifndef _SYS_SYSPROTO_H_
  622 struct ftruncate_args {
  623         int     fd;
  624         int     pad;
  625         off_t   length;
  626 };
  627 #endif
  628 int
  629 sys_ftruncate(td, uap)
  630         struct thread *td;
  631         struct ftruncate_args *uap;
  632 {
  633 
  634         return (kern_ftruncate(td, uap->fd, uap->length));
  635 }
  636 
  637 #if defined(COMPAT_43)
  638 #ifndef _SYS_SYSPROTO_H_
  639 struct oftruncate_args {
  640         int     fd;
  641         long    length;
  642 };
  643 #endif
  644 int
  645 oftruncate(td, uap)
  646         struct thread *td;
  647         struct oftruncate_args *uap;
  648 {
  649 
  650         return (kern_ftruncate(td, uap->fd, uap->length));
  651 }
  652 #endif /* COMPAT_43 */
  653 
  654 #ifndef _SYS_SYSPROTO_H_
  655 struct ioctl_args {
  656         int     fd;
  657         u_long  com;
  658         caddr_t data;
  659 };
  660 #endif
  661 /* ARGSUSED */
  662 int
  663 sys_ioctl(struct thread *td, struct ioctl_args *uap)
  664 {
  665         u_char smalldata[SYS_IOCTL_SMALL_SIZE] __aligned(SYS_IOCTL_SMALL_ALIGN);
  666         uint32_t com;
  667         int arg, error;
  668         u_int size;
  669         caddr_t data;
  670 
  671 #ifdef INVARIANTS
  672         if (uap->com > 0xffffffff) {
  673                 printf(
  674                     "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
  675                     td->td_proc->p_pid, td->td_name, uap->com);
  676         }
  677 #endif
  678         com = (uint32_t)uap->com;
  679 
  680         /*
  681          * Interpret high order word to find amount of data to be
  682          * copied to/from the user's address space.
  683          */
  684         size = IOCPARM_LEN(com);
  685         if ((size > IOCPARM_MAX) ||
  686             ((com & (IOC_VOID  | IOC_IN | IOC_OUT)) == 0) ||
  687 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
  688             ((com & IOC_OUT) && size == 0) ||
  689 #else
  690             ((com & (IOC_IN | IOC_OUT)) && size == 0) ||
  691 #endif
  692             ((com & IOC_VOID) && size > 0 && size != sizeof(int)))
  693                 return (ENOTTY);
  694 
  695         if (size > 0) {
  696                 if (com & IOC_VOID) {
  697                         /* Integer argument. */
  698                         arg = (intptr_t)uap->data;
  699                         data = (void *)&arg;
  700                         size = 0;
  701                 } else {
  702                         if (size > SYS_IOCTL_SMALL_SIZE)
  703                                 data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
  704                         else
  705                                 data = smalldata;
  706                 }
  707         } else
  708                 data = (void *)&uap->data;
  709         if (com & IOC_IN) {
  710                 error = copyin(uap->data, data, (u_int)size);
  711                 if (error != 0)
  712                         goto out;
  713         } else if (com & IOC_OUT) {
  714                 /*
  715                  * Zero the buffer so the user always
  716                  * gets back something deterministic.
  717                  */
  718                 bzero(data, size);
  719         }
  720 
  721         error = kern_ioctl(td, uap->fd, com, data);
  722 
  723         if (error == 0 && (com & IOC_OUT))
  724                 error = copyout(data, uap->data, (u_int)size);
  725 
  726 out:
  727         if (size > SYS_IOCTL_SMALL_SIZE)
  728                 free(data, M_IOCTLOPS);
  729         return (error);
  730 }
  731 
  732 int
  733 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
  734 {
  735         struct file *fp;
  736         struct filedesc *fdp;
  737 #ifndef CAPABILITIES
  738         cap_rights_t rights;
  739 #endif
  740         int error, tmp, locked;
  741 
  742         AUDIT_ARG_FD(fd);
  743         AUDIT_ARG_CMD(com);
  744 
  745         fdp = td->td_proc->p_fd;
  746 
  747         switch (com) {
  748         case FIONCLEX:
  749         case FIOCLEX:
  750                 FILEDESC_XLOCK(fdp);
  751                 locked = LA_XLOCKED;
  752                 break;
  753         default:
  754 #ifdef CAPABILITIES
  755                 FILEDESC_SLOCK(fdp);
  756                 locked = LA_SLOCKED;
  757 #else
  758                 locked = LA_UNLOCKED;
  759 #endif
  760                 break;
  761         }
  762 
  763 #ifdef CAPABILITIES
  764         if ((fp = fget_locked(fdp, fd)) == NULL) {
  765                 error = EBADF;
  766                 goto out;
  767         }
  768         if ((error = cap_ioctl_check(fdp, fd, com)) != 0) {
  769                 fp = NULL;      /* fhold() was not called yet */
  770                 goto out;
  771         }
  772         fhold(fp);
  773         if (locked == LA_SLOCKED) {
  774                 FILEDESC_SUNLOCK(fdp);
  775                 locked = LA_UNLOCKED;
  776         }
  777 #else
  778         error = fget(td, fd, cap_rights_init(&rights, CAP_IOCTL), &fp);
  779         if (error != 0) {
  780                 fp = NULL;
  781                 goto out;
  782         }
  783 #endif
  784         if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
  785                 error = EBADF;
  786                 goto out;
  787         }
  788 
  789         switch (com) {
  790         case FIONCLEX:
  791                 fdp->fd_ofiles[fd].fde_flags &= ~UF_EXCLOSE;
  792                 goto out;
  793         case FIOCLEX:
  794                 fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE;
  795                 goto out;
  796         case FIONBIO:
  797                 if ((tmp = *(int *)data))
  798                         atomic_set_int(&fp->f_flag, FNONBLOCK);
  799                 else
  800                         atomic_clear_int(&fp->f_flag, FNONBLOCK);
  801                 data = (void *)&tmp;
  802                 break;
  803         case FIOASYNC:
  804                 if ((tmp = *(int *)data))
  805                         atomic_set_int(&fp->f_flag, FASYNC);
  806                 else
  807                         atomic_clear_int(&fp->f_flag, FASYNC);
  808                 data = (void *)&tmp;
  809                 break;
  810         }
  811 
  812         error = fo_ioctl(fp, com, data, td->td_ucred, td);
  813 out:
  814         switch (locked) {
  815         case LA_XLOCKED:
  816                 FILEDESC_XUNLOCK(fdp);
  817                 break;
  818 #ifdef CAPABILITIES
  819         case LA_SLOCKED:
  820                 FILEDESC_SUNLOCK(fdp);
  821                 break;
  822 #endif
  823         default:
  824                 FILEDESC_UNLOCK_ASSERT(fdp);
  825                 break;
  826         }
  827         if (fp != NULL)
  828                 fdrop(fp, td);
  829         return (error);
  830 }
  831 
  832 int
  833 poll_no_poll(int events)
  834 {
  835         /*
  836          * Return true for read/write.  If the user asked for something
  837          * special, return POLLNVAL, so that clients have a way of
  838          * determining reliably whether or not the extended
  839          * functionality is present without hard-coding knowledge
  840          * of specific filesystem implementations.
  841          */
  842         if (events & ~POLLSTANDARD)
  843                 return (POLLNVAL);
  844 
  845         return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
  846 }
  847 
  848 int
  849 sys_pselect(struct thread *td, struct pselect_args *uap)
  850 {
  851         struct timespec ts;
  852         struct timeval tv, *tvp;
  853         sigset_t set, *uset;
  854         int error;
  855 
  856         if (uap->ts != NULL) {
  857                 error = copyin(uap->ts, &ts, sizeof(ts));
  858                 if (error != 0)
  859                     return (error);
  860                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
  861                 tvp = &tv;
  862         } else
  863                 tvp = NULL;
  864         if (uap->sm != NULL) {
  865                 error = copyin(uap->sm, &set, sizeof(set));
  866                 if (error != 0)
  867                         return (error);
  868                 uset = &set;
  869         } else
  870                 uset = NULL;
  871         return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  872             uset, NFDBITS));
  873 }
  874 
  875 int
  876 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
  877     struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
  878 {
  879         int error;
  880 
  881         if (uset != NULL) {
  882                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
  883                     &td->td_oldsigmask, 0);
  884                 if (error != 0)
  885                         return (error);
  886                 td->td_pflags |= TDP_OLDMASK;
  887                 /*
  888                  * Make sure that ast() is called on return to
  889                  * usermode and TDP_OLDMASK is cleared, restoring old
  890                  * sigmask.
  891                  */
  892                 thread_lock(td);
  893                 td->td_flags |= TDF_ASTPENDING;
  894                 thread_unlock(td);
  895         }
  896         error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
  897         return (error);
  898 }
  899 
  900 #ifndef _SYS_SYSPROTO_H_
  901 struct select_args {
  902         int     nd;
  903         fd_set  *in, *ou, *ex;
  904         struct  timeval *tv;
  905 };
  906 #endif
  907 int
  908 sys_select(struct thread *td, struct select_args *uap)
  909 {
  910         struct timeval tv, *tvp;
  911         int error;
  912 
  913         if (uap->tv != NULL) {
  914                 error = copyin(uap->tv, &tv, sizeof(tv));
  915                 if (error)
  916                         return (error);
  917                 tvp = &tv;
  918         } else
  919                 tvp = NULL;
  920 
  921         return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  922             NFDBITS));
  923 }
  924 
  925 /*
  926  * In the unlikely case when user specified n greater then the last
  927  * open file descriptor, check that no bits are set after the last
  928  * valid fd.  We must return EBADF if any is set.
  929  *
  930  * There are applications that rely on the behaviour.
  931  *
  932  * nd is fd_lastfile + 1.
  933  */
  934 static int
  935 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits)
  936 {
  937         char *addr, *oaddr;
  938         int b, i, res;
  939         uint8_t bits;
  940 
  941         if (nd >= ndu || fd_in == NULL)
  942                 return (0);
  943 
  944         oaddr = NULL;
  945         bits = 0; /* silence gcc */
  946         for (i = nd; i < ndu; i++) {
  947                 b = i / NBBY;
  948 #if BYTE_ORDER == LITTLE_ENDIAN
  949                 addr = (char *)fd_in + b;
  950 #else
  951                 addr = (char *)fd_in;
  952                 if (abi_nfdbits == NFDBITS) {
  953                         addr += rounddown(b, sizeof(fd_mask)) +
  954                             sizeof(fd_mask) - 1 - b % sizeof(fd_mask);
  955                 } else {
  956                         addr += rounddown(b, sizeof(uint32_t)) +
  957                             sizeof(uint32_t) - 1 - b % sizeof(uint32_t);
  958                 }
  959 #endif
  960                 if (addr != oaddr) {
  961                         res = fubyte(addr);
  962                         if (res == -1)
  963                                 return (EFAULT);
  964                         oaddr = addr;
  965                         bits = res;
  966                 }
  967                 if ((bits & (1 << (i % NBBY))) != 0)
  968                         return (EBADF);
  969         }
  970         return (0);
  971 }
  972 
  973 int
  974 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
  975     fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
  976 {
  977         struct filedesc *fdp;
  978         /*
  979          * The magic 2048 here is chosen to be just enough for FD_SETSIZE
  980          * infds with the new FD_SETSIZE of 1024, and more than enough for
  981          * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
  982          * of 256.
  983          */
  984         fd_mask s_selbits[howmany(2048, NFDBITS)];
  985         fd_mask *ibits[3], *obits[3], *selbits, *sbp;
  986         struct timeval rtv;
  987         sbintime_t asbt, precision, rsbt;
  988         u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
  989         int error, lf, ndu;
  990 
  991         if (nd < 0)
  992                 return (EINVAL);
  993         fdp = td->td_proc->p_fd;
  994         ndu = nd;
  995         lf = fdp->fd_lastfile;
  996         if (nd > lf + 1)
  997                 nd = lf + 1;
  998 
  999         error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits);
 1000         if (error != 0)
 1001                 return (error);
 1002         error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits);
 1003         if (error != 0)
 1004                 return (error);
 1005         error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits);
 1006         if (error != 0)
 1007                 return (error);
 1008 
 1009         /*
 1010          * Allocate just enough bits for the non-null fd_sets.  Use the
 1011          * preallocated auto buffer if possible.
 1012          */
 1013         nfdbits = roundup(nd, NFDBITS);
 1014         ncpbytes = nfdbits / NBBY;
 1015         ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
 1016         nbufbytes = 0;
 1017         if (fd_in != NULL)
 1018                 nbufbytes += 2 * ncpbytes;
 1019         if (fd_ou != NULL)
 1020                 nbufbytes += 2 * ncpbytes;
 1021         if (fd_ex != NULL)
 1022                 nbufbytes += 2 * ncpbytes;
 1023         if (nbufbytes <= sizeof s_selbits)
 1024                 selbits = &s_selbits[0];
 1025         else
 1026                 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
 1027 
 1028         /*
 1029          * Assign pointers into the bit buffers and fetch the input bits.
 1030          * Put the output buffers together so that they can be bzeroed
 1031          * together.
 1032          */
 1033         sbp = selbits;
 1034 #define getbits(name, x) \
 1035         do {                                                            \
 1036                 if (name == NULL) {                                     \
 1037                         ibits[x] = NULL;                                \
 1038                         obits[x] = NULL;                                \
 1039                 } else {                                                \
 1040                         ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp;   \
 1041                         obits[x] = sbp;                                 \
 1042                         sbp += ncpbytes / sizeof *sbp;                  \
 1043                         error = copyin(name, ibits[x], ncpubytes);      \
 1044                         if (error != 0)                                 \
 1045                                 goto done;                              \
 1046                         bzero((char *)ibits[x] + ncpubytes,             \
 1047                             ncpbytes - ncpubytes);                      \
 1048                 }                                                       \
 1049         } while (0)
 1050         getbits(fd_in, 0);
 1051         getbits(fd_ou, 1);
 1052         getbits(fd_ex, 2);
 1053 #undef  getbits
 1054 
 1055 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
 1056         /*
 1057          * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
 1058          * we are running under 32-bit emulation. This should be more
 1059          * generic.
 1060          */
 1061 #define swizzle_fdset(bits)                                             \
 1062         if (abi_nfdbits != NFDBITS && bits != NULL) {                   \
 1063                 int i;                                                  \
 1064                 for (i = 0; i < ncpbytes / sizeof *sbp; i++)            \
 1065                         bits[i] = (bits[i] >> 32) | (bits[i] << 32);    \
 1066         }
 1067 #else
 1068 #define swizzle_fdset(bits)
 1069 #endif
 1070 
 1071         /* Make sure the bit order makes it through an ABI transition */
 1072         swizzle_fdset(ibits[0]);
 1073         swizzle_fdset(ibits[1]);
 1074         swizzle_fdset(ibits[2]);
 1075         
 1076         if (nbufbytes != 0)
 1077                 bzero(selbits, nbufbytes / 2);
 1078 
 1079         precision = 0;
 1080         if (tvp != NULL) {
 1081                 rtv = *tvp;
 1082                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
 1083                     rtv.tv_usec >= 1000000) {
 1084                         error = EINVAL;
 1085                         goto done;
 1086                 }
 1087                 if (!timevalisset(&rtv))
 1088                         asbt = 0;
 1089                 else if (rtv.tv_sec <= INT32_MAX) {
 1090                         rsbt = tvtosbt(rtv);
 1091                         precision = rsbt;
 1092                         precision >>= tc_precexp;
 1093                         if (TIMESEL(&asbt, rsbt))
 1094                                 asbt += tc_tick_sbt;
 1095                         if (asbt <= SBT_MAX - rsbt)
 1096                                 asbt += rsbt;
 1097                         else
 1098                                 asbt = -1;
 1099                 } else
 1100                         asbt = -1;
 1101         } else
 1102                 asbt = -1;
 1103         seltdinit(td);
 1104         /* Iterate until the timeout expires or descriptors become ready. */
 1105         for (;;) {
 1106                 error = selscan(td, ibits, obits, nd);
 1107                 if (error || td->td_retval[0] != 0)
 1108                         break;
 1109                 error = seltdwait(td, asbt, precision);
 1110                 if (error)
 1111                         break;
 1112                 error = selrescan(td, ibits, obits);
 1113                 if (error || td->td_retval[0] != 0)
 1114                         break;
 1115         }
 1116         seltdclear(td);
 1117 
 1118 done:
 1119         /* select is not restarted after signals... */
 1120         if (error == ERESTART)
 1121                 error = EINTR;
 1122         if (error == EWOULDBLOCK)
 1123                 error = 0;
 1124 
 1125         /* swizzle bit order back, if necessary */
 1126         swizzle_fdset(obits[0]);
 1127         swizzle_fdset(obits[1]);
 1128         swizzle_fdset(obits[2]);
 1129 #undef swizzle_fdset
 1130 
 1131 #define putbits(name, x) \
 1132         if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
 1133                 error = error2;
 1134         if (error == 0) {
 1135                 int error2;
 1136 
 1137                 putbits(fd_in, 0);
 1138                 putbits(fd_ou, 1);
 1139                 putbits(fd_ex, 2);
 1140 #undef putbits
 1141         }
 1142         if (selbits != &s_selbits[0])
 1143                 free(selbits, M_SELECT);
 1144 
 1145         return (error);
 1146 }
 1147 /* 
 1148  * Convert a select bit set to poll flags.
 1149  *
 1150  * The backend always returns POLLHUP/POLLERR if appropriate and we
 1151  * return this as a set bit in any set.
 1152  */
 1153 static int select_flags[3] = {
 1154     POLLRDNORM | POLLHUP | POLLERR,
 1155     POLLWRNORM | POLLHUP | POLLERR,
 1156     POLLRDBAND | POLLERR
 1157 };
 1158 
 1159 /*
 1160  * Compute the fo_poll flags required for a fd given by the index and
 1161  * bit position in the fd_mask array.
 1162  */
 1163 static __inline int
 1164 selflags(fd_mask **ibits, int idx, fd_mask bit)
 1165 {
 1166         int flags;
 1167         int msk;
 1168 
 1169         flags = 0;
 1170         for (msk = 0; msk < 3; msk++) {
 1171                 if (ibits[msk] == NULL)
 1172                         continue;
 1173                 if ((ibits[msk][idx] & bit) == 0)
 1174                         continue;
 1175                 flags |= select_flags[msk];
 1176         }
 1177         return (flags);
 1178 }
 1179 
 1180 /*
 1181  * Set the appropriate output bits given a mask of fired events and the
 1182  * input bits originally requested.
 1183  */
 1184 static __inline int
 1185 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
 1186 {
 1187         int msk;
 1188         int n;
 1189 
 1190         n = 0;
 1191         for (msk = 0; msk < 3; msk++) {
 1192                 if ((events & select_flags[msk]) == 0)
 1193                         continue;
 1194                 if (ibits[msk] == NULL)
 1195                         continue;
 1196                 if ((ibits[msk][idx] & bit) == 0)
 1197                         continue;
 1198                 /*
 1199                  * XXX Check for a duplicate set.  This can occur because a
 1200                  * socket calls selrecord() twice for each poll() call
 1201                  * resulting in two selfds per real fd.  selrescan() will
 1202                  * call selsetbits twice as a result.
 1203                  */
 1204                 if ((obits[msk][idx] & bit) != 0)
 1205                         continue;
 1206                 obits[msk][idx] |= bit;
 1207                 n++;
 1208         }
 1209 
 1210         return (n);
 1211 }
 1212 
 1213 static __inline int
 1214 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp)
 1215 {
 1216         cap_rights_t rights;
 1217 
 1218         cap_rights_init(&rights, CAP_EVENT);
 1219 
 1220         return (fget_unlocked(fdp, fd, &rights, 0, fpp, NULL));
 1221 }
 1222 
 1223 /*
 1224  * Traverse the list of fds attached to this thread's seltd and check for
 1225  * completion.
 1226  */
 1227 static int
 1228 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
 1229 {
 1230         struct filedesc *fdp;
 1231         struct selinfo *si;
 1232         struct seltd *stp;
 1233         struct selfd *sfp;
 1234         struct selfd *sfn;
 1235         struct file *fp;
 1236         fd_mask bit;
 1237         int fd, ev, n, idx;
 1238         int error;
 1239 
 1240         fdp = td->td_proc->p_fd;
 1241         stp = td->td_sel;
 1242         n = 0;
 1243         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1244                 fd = (int)(uintptr_t)sfp->sf_cookie;
 1245                 si = sfp->sf_si;
 1246                 selfdfree(stp, sfp);
 1247                 /* If the selinfo wasn't cleared the event didn't fire. */
 1248                 if (si != NULL)
 1249                         continue;
 1250                 error = getselfd_cap(fdp, fd, &fp);
 1251                 if (error)
 1252                         return (error);
 1253                 idx = fd / NFDBITS;
 1254                 bit = (fd_mask)1 << (fd % NFDBITS);
 1255                 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
 1256                 fdrop(fp, td);
 1257                 if (ev != 0)
 1258                         n += selsetbits(ibits, obits, idx, bit, ev);
 1259         }
 1260         stp->st_flags = 0;
 1261         td->td_retval[0] = n;
 1262         return (0);
 1263 }
 1264 
 1265 /*
 1266  * Perform the initial filedescriptor scan and register ourselves with
 1267  * each selinfo.
 1268  */
 1269 static int
 1270 selscan(td, ibits, obits, nfd)
 1271         struct thread *td;
 1272         fd_mask **ibits, **obits;
 1273         int nfd;
 1274 {
 1275         struct filedesc *fdp;
 1276         struct file *fp;
 1277         fd_mask bit;
 1278         int ev, flags, end, fd;
 1279         int n, idx;
 1280         int error;
 1281 
 1282         fdp = td->td_proc->p_fd;
 1283         n = 0;
 1284         for (idx = 0, fd = 0; fd < nfd; idx++) {
 1285                 end = imin(fd + NFDBITS, nfd);
 1286                 for (bit = 1; fd < end; bit <<= 1, fd++) {
 1287                         /* Compute the list of events we're interested in. */
 1288                         flags = selflags(ibits, idx, bit);
 1289                         if (flags == 0)
 1290                                 continue;
 1291                         error = getselfd_cap(fdp, fd, &fp);
 1292                         if (error)
 1293                                 return (error);
 1294                         selfdalloc(td, (void *)(uintptr_t)fd);
 1295                         ev = fo_poll(fp, flags, td->td_ucred, td);
 1296                         fdrop(fp, td);
 1297                         if (ev != 0)
 1298                                 n += selsetbits(ibits, obits, idx, bit, ev);
 1299                 }
 1300         }
 1301 
 1302         td->td_retval[0] = n;
 1303         return (0);
 1304 }
 1305 
 1306 int
 1307 sys_poll(struct thread *td, struct poll_args *uap)
 1308 {
 1309         struct timespec ts, *tsp;
 1310 
 1311         if (uap->timeout != INFTIM) {
 1312                 if (uap->timeout < 0)
 1313                         return (EINVAL);
 1314                 ts.tv_sec = uap->timeout / 1000;
 1315                 ts.tv_nsec = (uap->timeout % 1000) * 1000000;
 1316                 tsp = &ts;
 1317         } else
 1318                 tsp = NULL;
 1319 
 1320         return (kern_poll(td, uap->fds, uap->nfds, tsp, NULL));
 1321 }
 1322 
 1323 int
 1324 kern_poll(struct thread *td, struct pollfd *fds, u_int nfds,
 1325     struct timespec *tsp, sigset_t *uset)
 1326 {
 1327         struct pollfd *bits;
 1328         struct pollfd smallbits[32];
 1329         sbintime_t sbt, precision, tmp;
 1330         time_t over;
 1331         struct timespec ts;
 1332         int error;
 1333         size_t ni;
 1334 
 1335         precision = 0;
 1336         if (tsp != NULL) {
 1337                 if (tsp->tv_sec < 0)
 1338                         return (EINVAL);
 1339                 if (tsp->tv_nsec < 0 || tsp->tv_nsec >= 1000000000)
 1340                         return (EINVAL);
 1341                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
 1342                         sbt = 0;
 1343                 else {
 1344                         ts = *tsp;
 1345                         if (ts.tv_sec > INT32_MAX / 2) {
 1346                                 over = ts.tv_sec - INT32_MAX / 2;
 1347                                 ts.tv_sec -= over;
 1348                         } else
 1349                                 over = 0;
 1350                         tmp = tstosbt(ts);
 1351                         precision = tmp;
 1352                         precision >>= tc_precexp;
 1353                         if (TIMESEL(&sbt, tmp))
 1354                                 sbt += tc_tick_sbt;
 1355                         sbt += tmp;
 1356                 }
 1357         } else
 1358                 sbt = -1;
 1359 
 1360         if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 
 1361                 return (EINVAL);
 1362         ni = nfds * sizeof(struct pollfd);
 1363         if (ni > sizeof(smallbits))
 1364                 bits = malloc(ni, M_TEMP, M_WAITOK);
 1365         else
 1366                 bits = smallbits;
 1367         error = copyin(fds, bits, ni);
 1368         if (error)
 1369                 goto done;
 1370 
 1371         if (uset != NULL) {
 1372                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
 1373                     &td->td_oldsigmask, 0);
 1374                 if (error)
 1375                         goto done;
 1376                 td->td_pflags |= TDP_OLDMASK;
 1377                 /*
 1378                  * Make sure that ast() is called on return to
 1379                  * usermode and TDP_OLDMASK is cleared, restoring old
 1380                  * sigmask.
 1381                  */
 1382                 thread_lock(td);
 1383                 td->td_flags |= TDF_ASTPENDING;
 1384                 thread_unlock(td);
 1385         }
 1386 
 1387         seltdinit(td);
 1388         /* Iterate until the timeout expires or descriptors become ready. */
 1389         for (;;) {
 1390                 error = pollscan(td, bits, nfds);
 1391                 if (error || td->td_retval[0] != 0)
 1392                         break;
 1393                 error = seltdwait(td, sbt, precision);
 1394                 if (error)
 1395                         break;
 1396                 error = pollrescan(td);
 1397                 if (error || td->td_retval[0] != 0)
 1398                         break;
 1399         }
 1400         seltdclear(td);
 1401 
 1402 done:
 1403         /* poll is not restarted after signals... */
 1404         if (error == ERESTART)
 1405                 error = EINTR;
 1406         if (error == EWOULDBLOCK)
 1407                 error = 0;
 1408         if (error == 0) {
 1409                 error = pollout(td, bits, fds, nfds);
 1410                 if (error)
 1411                         goto out;
 1412         }
 1413 out:
 1414         if (ni > sizeof(smallbits))
 1415                 free(bits, M_TEMP);
 1416         return (error);
 1417 }
 1418 
 1419 int
 1420 sys_ppoll(struct thread *td, struct ppoll_args *uap)
 1421 {
 1422         struct timespec ts, *tsp;
 1423         sigset_t set, *ssp;
 1424         int error;
 1425 
 1426         if (uap->ts != NULL) {
 1427                 error = copyin(uap->ts, &ts, sizeof(ts));
 1428                 if (error)
 1429                         return (error);
 1430                 tsp = &ts;
 1431         } else
 1432                 tsp = NULL;
 1433         if (uap->set != NULL) {
 1434                 error = copyin(uap->set, &set, sizeof(set));
 1435                 if (error)
 1436                         return (error);
 1437                 ssp = &set;
 1438         } else
 1439                 ssp = NULL;
 1440         /*
 1441          * fds is still a pointer to user space. kern_poll() will
 1442          * take care of copyin that array to the kernel space.
 1443          */
 1444 
 1445         return (kern_poll(td, uap->fds, uap->nfds, tsp, ssp));
 1446 }
 1447 
 1448 static int
 1449 pollrescan(struct thread *td)
 1450 {
 1451         struct seltd *stp;
 1452         struct selfd *sfp;
 1453         struct selfd *sfn;
 1454         struct selinfo *si;
 1455         struct filedesc *fdp;
 1456         struct file *fp;
 1457         struct pollfd *fd;
 1458 #ifdef CAPABILITIES
 1459         cap_rights_t rights;
 1460 #endif
 1461         int n;
 1462 
 1463         n = 0;
 1464         fdp = td->td_proc->p_fd;
 1465         stp = td->td_sel;
 1466         FILEDESC_SLOCK(fdp);
 1467         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1468                 fd = (struct pollfd *)sfp->sf_cookie;
 1469                 si = sfp->sf_si;
 1470                 selfdfree(stp, sfp);
 1471                 /* If the selinfo wasn't cleared the event didn't fire. */
 1472                 if (si != NULL)
 1473                         continue;
 1474                 fp = fdp->fd_ofiles[fd->fd].fde_file;
 1475 #ifdef CAPABILITIES
 1476                 if (fp == NULL ||
 1477                     cap_check(cap_rights(fdp, fd->fd),
 1478                     cap_rights_init(&rights, CAP_EVENT)) != 0)
 1479 #else
 1480                 if (fp == NULL)
 1481 #endif
 1482                 {
 1483                         fd->revents = POLLNVAL;
 1484                         n++;
 1485                         continue;
 1486                 }
 1487 
 1488                 /*
 1489                  * Note: backend also returns POLLHUP and
 1490                  * POLLERR if appropriate.
 1491                  */
 1492                 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
 1493                 if (fd->revents != 0)
 1494                         n++;
 1495         }
 1496         FILEDESC_SUNLOCK(fdp);
 1497         stp->st_flags = 0;
 1498         td->td_retval[0] = n;
 1499         return (0);
 1500 }
 1501 
 1502 
 1503 static int
 1504 pollout(td, fds, ufds, nfd)
 1505         struct thread *td;
 1506         struct pollfd *fds;
 1507         struct pollfd *ufds;
 1508         u_int nfd;
 1509 {
 1510         int error = 0;
 1511         u_int i = 0;
 1512         u_int n = 0;
 1513 
 1514         for (i = 0; i < nfd; i++) {
 1515                 error = copyout(&fds->revents, &ufds->revents,
 1516                     sizeof(ufds->revents));
 1517                 if (error)
 1518                         return (error);
 1519                 if (fds->revents != 0)
 1520                         n++;
 1521                 fds++;
 1522                 ufds++;
 1523         }
 1524         td->td_retval[0] = n;
 1525         return (0);
 1526 }
 1527 
 1528 static int
 1529 pollscan(td, fds, nfd)
 1530         struct thread *td;
 1531         struct pollfd *fds;
 1532         u_int nfd;
 1533 {
 1534         struct filedesc *fdp = td->td_proc->p_fd;
 1535         struct file *fp;
 1536 #ifdef CAPABILITIES
 1537         cap_rights_t rights;
 1538 #endif
 1539         int i, n = 0;
 1540 
 1541         FILEDESC_SLOCK(fdp);
 1542         for (i = 0; i < nfd; i++, fds++) {
 1543                 if (fds->fd > fdp->fd_lastfile) {
 1544                         fds->revents = POLLNVAL;
 1545                         n++;
 1546                 } else if (fds->fd < 0) {
 1547                         fds->revents = 0;
 1548                 } else {
 1549                         fp = fdp->fd_ofiles[fds->fd].fde_file;
 1550 #ifdef CAPABILITIES
 1551                         if (fp == NULL ||
 1552                             cap_check(cap_rights(fdp, fds->fd),
 1553                             cap_rights_init(&rights, CAP_EVENT)) != 0)
 1554 #else
 1555                         if (fp == NULL)
 1556 #endif
 1557                         {
 1558                                 fds->revents = POLLNVAL;
 1559                                 n++;
 1560                         } else {
 1561                                 /*
 1562                                  * Note: backend also returns POLLHUP and
 1563                                  * POLLERR if appropriate.
 1564                                  */
 1565                                 selfdalloc(td, fds);
 1566                                 fds->revents = fo_poll(fp, fds->events,
 1567                                     td->td_ucred, td);
 1568                                 /*
 1569                                  * POSIX requires POLLOUT to be never
 1570                                  * set simultaneously with POLLHUP.
 1571                                  */
 1572                                 if ((fds->revents & POLLHUP) != 0)
 1573                                         fds->revents &= ~POLLOUT;
 1574 
 1575                                 if (fds->revents != 0)
 1576                                         n++;
 1577                         }
 1578                 }
 1579         }
 1580         FILEDESC_SUNLOCK(fdp);
 1581         td->td_retval[0] = n;
 1582         return (0);
 1583 }
 1584 
 1585 /*
 1586  * OpenBSD poll system call.
 1587  *
 1588  * XXX this isn't quite a true representation..  OpenBSD uses select ops.
 1589  */
 1590 #ifndef _SYS_SYSPROTO_H_
 1591 struct openbsd_poll_args {
 1592         struct pollfd *fds;
 1593         u_int   nfds;
 1594         int     timeout;
 1595 };
 1596 #endif
 1597 int
 1598 sys_openbsd_poll(td, uap)
 1599         register struct thread *td;
 1600         register struct openbsd_poll_args *uap;
 1601 {
 1602         return (sys_poll(td, (struct poll_args *)uap));
 1603 }
 1604 
 1605 /*
 1606  * XXX This was created specifically to support netncp and netsmb.  This
 1607  * allows the caller to specify a socket to wait for events on.  It returns
 1608  * 0 if any events matched and an error otherwise.  There is no way to
 1609  * determine which events fired.
 1610  */
 1611 int
 1612 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
 1613 {
 1614         struct timeval rtv;
 1615         sbintime_t asbt, precision, rsbt;
 1616         int error;
 1617 
 1618         precision = 0;  /* stupid gcc! */
 1619         if (tvp != NULL) {
 1620                 rtv = *tvp;
 1621                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 || 
 1622                     rtv.tv_usec >= 1000000)
 1623                         return (EINVAL);
 1624                 if (!timevalisset(&rtv))
 1625                         asbt = 0;
 1626                 else if (rtv.tv_sec <= INT32_MAX) {
 1627                         rsbt = tvtosbt(rtv);
 1628                         precision = rsbt;
 1629                         precision >>= tc_precexp;
 1630                         if (TIMESEL(&asbt, rsbt))
 1631                                 asbt += tc_tick_sbt;
 1632                         if (asbt <= SBT_MAX - rsbt)
 1633                                 asbt += rsbt;
 1634                         else
 1635                                 asbt = -1;
 1636                 } else
 1637                         asbt = -1;
 1638         } else
 1639                 asbt = -1;
 1640         seltdinit(td);
 1641         /*
 1642          * Iterate until the timeout expires or the socket becomes ready.
 1643          */
 1644         for (;;) {
 1645                 selfdalloc(td, NULL);
 1646                 error = sopoll(so, events, NULL, td);
 1647                 /* error here is actually the ready events. */
 1648                 if (error)
 1649                         return (0);
 1650                 error = seltdwait(td, asbt, precision);
 1651                 if (error)
 1652                         break;
 1653         }
 1654         seltdclear(td);
 1655         /* XXX Duplicates ncp/smb behavior. */
 1656         if (error == ERESTART)
 1657                 error = 0;
 1658         return (error);
 1659 }
 1660 
 1661 /*
 1662  * Preallocate two selfds associated with 'cookie'.  Some fo_poll routines
 1663  * have two select sets, one for read and another for write.
 1664  */
 1665 static void
 1666 selfdalloc(struct thread *td, void *cookie)
 1667 {
 1668         struct seltd *stp;
 1669 
 1670         stp = td->td_sel;
 1671         if (stp->st_free1 == NULL)
 1672                 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1673         stp->st_free1->sf_td = stp;
 1674         stp->st_free1->sf_cookie = cookie;
 1675         if (stp->st_free2 == NULL)
 1676                 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1677         stp->st_free2->sf_td = stp;
 1678         stp->st_free2->sf_cookie = cookie;
 1679 }
 1680 
 1681 static void
 1682 selfdfree(struct seltd *stp, struct selfd *sfp)
 1683 {
 1684         STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
 1685         mtx_lock(sfp->sf_mtx);
 1686         if (sfp->sf_si)
 1687                 TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
 1688         mtx_unlock(sfp->sf_mtx);
 1689         uma_zfree(selfd_zone, sfp);
 1690 }
 1691 
 1692 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */
 1693 void
 1694 seldrain(sip)
 1695         struct selinfo *sip;
 1696 {
 1697 
 1698         /*
 1699          * This feature is already provided by doselwakeup(), thus it is
 1700          * enough to go for it.
 1701          * Eventually, the context, should take care to avoid races
 1702          * between thread calling select()/poll() and file descriptor
 1703          * detaching, but, again, the races are just the same as
 1704          * selwakeup().
 1705          */
 1706         doselwakeup(sip, -1);
 1707 }
 1708 
 1709 /*
 1710  * Record a select request.
 1711  */
 1712 void
 1713 selrecord(selector, sip)
 1714         struct thread *selector;
 1715         struct selinfo *sip;
 1716 {
 1717         struct selfd *sfp;
 1718         struct seltd *stp;
 1719         struct mtx *mtxp;
 1720 
 1721         stp = selector->td_sel;
 1722         /*
 1723          * Don't record when doing a rescan.
 1724          */
 1725         if (stp->st_flags & SELTD_RESCAN)
 1726                 return;
 1727         /*
 1728          * Grab one of the preallocated descriptors.
 1729          */
 1730         sfp = NULL;
 1731         if ((sfp = stp->st_free1) != NULL)
 1732                 stp->st_free1 = NULL;
 1733         else if ((sfp = stp->st_free2) != NULL)
 1734                 stp->st_free2 = NULL;
 1735         else
 1736                 panic("selrecord: No free selfd on selq");
 1737         mtxp = sip->si_mtx;
 1738         if (mtxp == NULL)
 1739                 mtxp = mtx_pool_find(mtxpool_select, sip);
 1740         /*
 1741          * Initialize the sfp and queue it in the thread.
 1742          */
 1743         sfp->sf_si = sip;
 1744         sfp->sf_mtx = mtxp;
 1745         STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
 1746         /*
 1747          * Now that we've locked the sip, check for initialization.
 1748          */
 1749         mtx_lock(mtxp);
 1750         if (sip->si_mtx == NULL) {
 1751                 sip->si_mtx = mtxp;
 1752                 TAILQ_INIT(&sip->si_tdlist);
 1753         }
 1754         /*
 1755          * Add this thread to the list of selfds listening on this selinfo.
 1756          */
 1757         TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
 1758         mtx_unlock(sip->si_mtx);
 1759 }
 1760 
 1761 /* Wake up a selecting thread. */
 1762 void
 1763 selwakeup(sip)
 1764         struct selinfo *sip;
 1765 {
 1766         doselwakeup(sip, -1);
 1767 }
 1768 
 1769 /* Wake up a selecting thread, and set its priority. */
 1770 void
 1771 selwakeuppri(sip, pri)
 1772         struct selinfo *sip;
 1773         int pri;
 1774 {
 1775         doselwakeup(sip, pri);
 1776 }
 1777 
 1778 /*
 1779  * Do a wakeup when a selectable event occurs.
 1780  */
 1781 static void
 1782 doselwakeup(sip, pri)
 1783         struct selinfo *sip;
 1784         int pri;
 1785 {
 1786         struct selfd *sfp;
 1787         struct selfd *sfn;
 1788         struct seltd *stp;
 1789 
 1790         /* If it's not initialized there can't be any waiters. */
 1791         if (sip->si_mtx == NULL)
 1792                 return;
 1793         /*
 1794          * Locking the selinfo locks all selfds associated with it.
 1795          */
 1796         mtx_lock(sip->si_mtx);
 1797         TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
 1798                 /*
 1799                  * Once we remove this sfp from the list and clear the
 1800                  * sf_si seltdclear will know to ignore this si.
 1801                  */
 1802                 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
 1803                 sfp->sf_si = NULL;
 1804                 stp = sfp->sf_td;
 1805                 mtx_lock(&stp->st_mtx);
 1806                 stp->st_flags |= SELTD_PENDING;
 1807                 cv_broadcastpri(&stp->st_wait, pri);
 1808                 mtx_unlock(&stp->st_mtx);
 1809         }
 1810         mtx_unlock(sip->si_mtx);
 1811 }
 1812 
 1813 static void
 1814 seltdinit(struct thread *td)
 1815 {
 1816         struct seltd *stp;
 1817 
 1818         if ((stp = td->td_sel) != NULL)
 1819                 goto out;
 1820         td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
 1821         mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
 1822         cv_init(&stp->st_wait, "select");
 1823 out:
 1824         stp->st_flags = 0;
 1825         STAILQ_INIT(&stp->st_selq);
 1826 }
 1827 
 1828 static int
 1829 seltdwait(struct thread *td, sbintime_t sbt, sbintime_t precision)
 1830 {
 1831         struct seltd *stp;
 1832         int error;
 1833 
 1834         stp = td->td_sel;
 1835         /*
 1836          * An event of interest may occur while we do not hold the seltd
 1837          * locked so check the pending flag before we sleep.
 1838          */
 1839         mtx_lock(&stp->st_mtx);
 1840         /*
 1841          * Any further calls to selrecord will be a rescan.
 1842          */
 1843         stp->st_flags |= SELTD_RESCAN;
 1844         if (stp->st_flags & SELTD_PENDING) {
 1845                 mtx_unlock(&stp->st_mtx);
 1846                 return (0);
 1847         }
 1848         if (sbt == 0)
 1849                 error = EWOULDBLOCK;
 1850         else if (sbt != -1)
 1851                 error = cv_timedwait_sig_sbt(&stp->st_wait, &stp->st_mtx,
 1852                     sbt, precision, C_ABSOLUTE);
 1853         else
 1854                 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
 1855         mtx_unlock(&stp->st_mtx);
 1856 
 1857         return (error);
 1858 }
 1859 
 1860 void
 1861 seltdfini(struct thread *td)
 1862 {
 1863         struct seltd *stp;
 1864 
 1865         stp = td->td_sel;
 1866         if (stp == NULL)
 1867                 return;
 1868         if (stp->st_free1)
 1869                 uma_zfree(selfd_zone, stp->st_free1);
 1870         if (stp->st_free2)
 1871                 uma_zfree(selfd_zone, stp->st_free2);
 1872         td->td_sel = NULL;
 1873         free(stp, M_SELECT);
 1874 }
 1875 
 1876 /*
 1877  * Remove the references to the thread from all of the objects we were
 1878  * polling.
 1879  */
 1880 static void
 1881 seltdclear(struct thread *td)
 1882 {
 1883         struct seltd *stp;
 1884         struct selfd *sfp;
 1885         struct selfd *sfn;
 1886 
 1887         stp = td->td_sel;
 1888         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
 1889                 selfdfree(stp, sfp);
 1890         stp->st_flags = 0;
 1891 }
 1892 
 1893 static void selectinit(void *);
 1894 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
 1895 static void
 1896 selectinit(void *dummy __unused)
 1897 {
 1898 
 1899         selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
 1900             NULL, NULL, UMA_ALIGN_PTR, 0);
 1901         mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
 1902 }

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