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 315481 2017-03-18 12:39:24Z mmokhi $");
   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         u_long com;
  667         int arg, error;
  668         u_int size;
  669         caddr_t data;
  670 
  671         if (uap->com > 0xffffffff) {
  672                 printf(
  673                     "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
  674                     td->td_proc->p_pid, td->td_name, uap->com);
  675                 uap->com &= 0xffffffff;
  676         }
  677         com = uap->com;
  678 
  679         /*
  680          * Interpret high order word to find amount of data to be
  681          * copied to/from the user's address space.
  682          */
  683         size = IOCPARM_LEN(com);
  684         if ((size > IOCPARM_MAX) ||
  685             ((com & (IOC_VOID  | IOC_IN | IOC_OUT)) == 0) ||
  686 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
  687             ((com & IOC_OUT) && size == 0) ||
  688 #else
  689             ((com & (IOC_IN | IOC_OUT)) && size == 0) ||
  690 #endif
  691             ((com & IOC_VOID) && size > 0 && size != sizeof(int)))
  692                 return (ENOTTY);
  693 
  694         if (size > 0) {
  695                 if (com & IOC_VOID) {
  696                         /* Integer argument. */
  697                         arg = (intptr_t)uap->data;
  698                         data = (void *)&arg;
  699                         size = 0;
  700                 } else {
  701                         if (size > SYS_IOCTL_SMALL_SIZE)
  702                                 data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
  703                         else
  704                                 data = smalldata;
  705                 }
  706         } else
  707                 data = (void *)&uap->data;
  708         if (com & IOC_IN) {
  709                 error = copyin(uap->data, data, (u_int)size);
  710                 if (error != 0)
  711                         goto out;
  712         } else if (com & IOC_OUT) {
  713                 /*
  714                  * Zero the buffer so the user always
  715                  * gets back something deterministic.
  716                  */
  717                 bzero(data, size);
  718         }
  719 
  720         error = kern_ioctl(td, uap->fd, com, data);
  721 
  722         if (error == 0 && (com & IOC_OUT))
  723                 error = copyout(data, uap->data, (u_int)size);
  724 
  725 out:
  726         if (size > SYS_IOCTL_SMALL_SIZE)
  727                 free(data, M_IOCTLOPS);
  728         return (error);
  729 }
  730 
  731 int
  732 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
  733 {
  734         struct file *fp;
  735         struct filedesc *fdp;
  736 #ifndef CAPABILITIES
  737         cap_rights_t rights;
  738 #endif
  739         int error, tmp, locked;
  740 
  741         AUDIT_ARG_FD(fd);
  742         AUDIT_ARG_CMD(com);
  743 
  744         fdp = td->td_proc->p_fd;
  745 
  746         switch (com) {
  747         case FIONCLEX:
  748         case FIOCLEX:
  749                 FILEDESC_XLOCK(fdp);
  750                 locked = LA_XLOCKED;
  751                 break;
  752         default:
  753 #ifdef CAPABILITIES
  754                 FILEDESC_SLOCK(fdp);
  755                 locked = LA_SLOCKED;
  756 #else
  757                 locked = LA_UNLOCKED;
  758 #endif
  759                 break;
  760         }
  761 
  762 #ifdef CAPABILITIES
  763         if ((fp = fget_locked(fdp, fd)) == NULL) {
  764                 error = EBADF;
  765                 goto out;
  766         }
  767         if ((error = cap_ioctl_check(fdp, fd, com)) != 0) {
  768                 fp = NULL;      /* fhold() was not called yet */
  769                 goto out;
  770         }
  771         fhold(fp);
  772         if (locked == LA_SLOCKED) {
  773                 FILEDESC_SUNLOCK(fdp);
  774                 locked = LA_UNLOCKED;
  775         }
  776 #else
  777         error = fget(td, fd, cap_rights_init(&rights, CAP_IOCTL), &fp);
  778         if (error != 0) {
  779                 fp = NULL;
  780                 goto out;
  781         }
  782 #endif
  783         if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
  784                 error = EBADF;
  785                 goto out;
  786         }
  787 
  788         switch (com) {
  789         case FIONCLEX:
  790                 fdp->fd_ofiles[fd].fde_flags &= ~UF_EXCLOSE;
  791                 goto out;
  792         case FIOCLEX:
  793                 fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE;
  794                 goto out;
  795         case FIONBIO:
  796                 if ((tmp = *(int *)data))
  797                         atomic_set_int(&fp->f_flag, FNONBLOCK);
  798                 else
  799                         atomic_clear_int(&fp->f_flag, FNONBLOCK);
  800                 data = (void *)&tmp;
  801                 break;
  802         case FIOASYNC:
  803                 if ((tmp = *(int *)data))
  804                         atomic_set_int(&fp->f_flag, FASYNC);
  805                 else
  806                         atomic_clear_int(&fp->f_flag, FASYNC);
  807                 data = (void *)&tmp;
  808                 break;
  809         }
  810 
  811         error = fo_ioctl(fp, com, data, td->td_ucred, td);
  812 out:
  813         switch (locked) {
  814         case LA_XLOCKED:
  815                 FILEDESC_XUNLOCK(fdp);
  816                 break;
  817 #ifdef CAPABILITIES
  818         case LA_SLOCKED:
  819                 FILEDESC_SUNLOCK(fdp);
  820                 break;
  821 #endif
  822         default:
  823                 FILEDESC_UNLOCK_ASSERT(fdp);
  824                 break;
  825         }
  826         if (fp != NULL)
  827                 fdrop(fp, td);
  828         return (error);
  829 }
  830 
  831 int
  832 poll_no_poll(int events)
  833 {
  834         /*
  835          * Return true for read/write.  If the user asked for something
  836          * special, return POLLNVAL, so that clients have a way of
  837          * determining reliably whether or not the extended
  838          * functionality is present without hard-coding knowledge
  839          * of specific filesystem implementations.
  840          */
  841         if (events & ~POLLSTANDARD)
  842                 return (POLLNVAL);
  843 
  844         return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
  845 }
  846 
  847 int
  848 sys_pselect(struct thread *td, struct pselect_args *uap)
  849 {
  850         struct timespec ts;
  851         struct timeval tv, *tvp;
  852         sigset_t set, *uset;
  853         int error;
  854 
  855         if (uap->ts != NULL) {
  856                 error = copyin(uap->ts, &ts, sizeof(ts));
  857                 if (error != 0)
  858                     return (error);
  859                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
  860                 tvp = &tv;
  861         } else
  862                 tvp = NULL;
  863         if (uap->sm != NULL) {
  864                 error = copyin(uap->sm, &set, sizeof(set));
  865                 if (error != 0)
  866                         return (error);
  867                 uset = &set;
  868         } else
  869                 uset = NULL;
  870         return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  871             uset, NFDBITS));
  872 }
  873 
  874 int
  875 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
  876     struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
  877 {
  878         int error;
  879 
  880         if (uset != NULL) {
  881                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
  882                     &td->td_oldsigmask, 0);
  883                 if (error != 0)
  884                         return (error);
  885                 td->td_pflags |= TDP_OLDMASK;
  886                 /*
  887                  * Make sure that ast() is called on return to
  888                  * usermode and TDP_OLDMASK is cleared, restoring old
  889                  * sigmask.
  890                  */
  891                 thread_lock(td);
  892                 td->td_flags |= TDF_ASTPENDING;
  893                 thread_unlock(td);
  894         }
  895         error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
  896         return (error);
  897 }
  898 
  899 #ifndef _SYS_SYSPROTO_H_
  900 struct select_args {
  901         int     nd;
  902         fd_set  *in, *ou, *ex;
  903         struct  timeval *tv;
  904 };
  905 #endif
  906 int
  907 sys_select(struct thread *td, struct select_args *uap)
  908 {
  909         struct timeval tv, *tvp;
  910         int error;
  911 
  912         if (uap->tv != NULL) {
  913                 error = copyin(uap->tv, &tv, sizeof(tv));
  914                 if (error)
  915                         return (error);
  916                 tvp = &tv;
  917         } else
  918                 tvp = NULL;
  919 
  920         return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  921             NFDBITS));
  922 }
  923 
  924 /*
  925  * In the unlikely case when user specified n greater then the last
  926  * open file descriptor, check that no bits are set after the last
  927  * valid fd.  We must return EBADF if any is set.
  928  *
  929  * There are applications that rely on the behaviour.
  930  *
  931  * nd is fd_lastfile + 1.
  932  */
  933 static int
  934 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits)
  935 {
  936         char *addr, *oaddr;
  937         int b, i, res;
  938         uint8_t bits;
  939 
  940         if (nd >= ndu || fd_in == NULL)
  941                 return (0);
  942 
  943         oaddr = NULL;
  944         bits = 0; /* silence gcc */
  945         for (i = nd; i < ndu; i++) {
  946                 b = i / NBBY;
  947 #if BYTE_ORDER == LITTLE_ENDIAN
  948                 addr = (char *)fd_in + b;
  949 #else
  950                 addr = (char *)fd_in;
  951                 if (abi_nfdbits == NFDBITS) {
  952                         addr += rounddown(b, sizeof(fd_mask)) +
  953                             sizeof(fd_mask) - 1 - b % sizeof(fd_mask);
  954                 } else {
  955                         addr += rounddown(b, sizeof(uint32_t)) +
  956                             sizeof(uint32_t) - 1 - b % sizeof(uint32_t);
  957                 }
  958 #endif
  959                 if (addr != oaddr) {
  960                         res = fubyte(addr);
  961                         if (res == -1)
  962                                 return (EFAULT);
  963                         oaddr = addr;
  964                         bits = res;
  965                 }
  966                 if ((bits & (1 << (i % NBBY))) != 0)
  967                         return (EBADF);
  968         }
  969         return (0);
  970 }
  971 
  972 int
  973 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
  974     fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
  975 {
  976         struct filedesc *fdp;
  977         /*
  978          * The magic 2048 here is chosen to be just enough for FD_SETSIZE
  979          * infds with the new FD_SETSIZE of 1024, and more than enough for
  980          * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
  981          * of 256.
  982          */
  983         fd_mask s_selbits[howmany(2048, NFDBITS)];
  984         fd_mask *ibits[3], *obits[3], *selbits, *sbp;
  985         struct timeval rtv;
  986         sbintime_t asbt, precision, rsbt;
  987         u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
  988         int error, lf, ndu;
  989 
  990         if (nd < 0)
  991                 return (EINVAL);
  992         fdp = td->td_proc->p_fd;
  993         ndu = nd;
  994         lf = fdp->fd_lastfile;
  995         if (nd > lf + 1)
  996                 nd = lf + 1;
  997 
  998         error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits);
  999         if (error != 0)
 1000                 return (error);
 1001         error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits);
 1002         if (error != 0)
 1003                 return (error);
 1004         error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits);
 1005         if (error != 0)
 1006                 return (error);
 1007 
 1008         /*
 1009          * Allocate just enough bits for the non-null fd_sets.  Use the
 1010          * preallocated auto buffer if possible.
 1011          */
 1012         nfdbits = roundup(nd, NFDBITS);
 1013         ncpbytes = nfdbits / NBBY;
 1014         ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
 1015         nbufbytes = 0;
 1016         if (fd_in != NULL)
 1017                 nbufbytes += 2 * ncpbytes;
 1018         if (fd_ou != NULL)
 1019                 nbufbytes += 2 * ncpbytes;
 1020         if (fd_ex != NULL)
 1021                 nbufbytes += 2 * ncpbytes;
 1022         if (nbufbytes <= sizeof s_selbits)
 1023                 selbits = &s_selbits[0];
 1024         else
 1025                 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
 1026 
 1027         /*
 1028          * Assign pointers into the bit buffers and fetch the input bits.
 1029          * Put the output buffers together so that they can be bzeroed
 1030          * together.
 1031          */
 1032         sbp = selbits;
 1033 #define getbits(name, x) \
 1034         do {                                                            \
 1035                 if (name == NULL) {                                     \
 1036                         ibits[x] = NULL;                                \
 1037                         obits[x] = NULL;                                \
 1038                 } else {                                                \
 1039                         ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp;   \
 1040                         obits[x] = sbp;                                 \
 1041                         sbp += ncpbytes / sizeof *sbp;                  \
 1042                         error = copyin(name, ibits[x], ncpubytes);      \
 1043                         if (error != 0)                                 \
 1044                                 goto done;                              \
 1045                         bzero((char *)ibits[x] + ncpubytes,             \
 1046                             ncpbytes - ncpubytes);                      \
 1047                 }                                                       \
 1048         } while (0)
 1049         getbits(fd_in, 0);
 1050         getbits(fd_ou, 1);
 1051         getbits(fd_ex, 2);
 1052 #undef  getbits
 1053 
 1054 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
 1055         /*
 1056          * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
 1057          * we are running under 32-bit emulation. This should be more
 1058          * generic.
 1059          */
 1060 #define swizzle_fdset(bits)                                             \
 1061         if (abi_nfdbits != NFDBITS && bits != NULL) {                   \
 1062                 int i;                                                  \
 1063                 for (i = 0; i < ncpbytes / sizeof *sbp; i++)            \
 1064                         bits[i] = (bits[i] >> 32) | (bits[i] << 32);    \
 1065         }
 1066 #else
 1067 #define swizzle_fdset(bits)
 1068 #endif
 1069 
 1070         /* Make sure the bit order makes it through an ABI transition */
 1071         swizzle_fdset(ibits[0]);
 1072         swizzle_fdset(ibits[1]);
 1073         swizzle_fdset(ibits[2]);
 1074         
 1075         if (nbufbytes != 0)
 1076                 bzero(selbits, nbufbytes / 2);
 1077 
 1078         precision = 0;
 1079         if (tvp != NULL) {
 1080                 rtv = *tvp;
 1081                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
 1082                     rtv.tv_usec >= 1000000) {
 1083                         error = EINVAL;
 1084                         goto done;
 1085                 }
 1086                 if (!timevalisset(&rtv))
 1087                         asbt = 0;
 1088                 else if (rtv.tv_sec <= INT32_MAX) {
 1089                         rsbt = tvtosbt(rtv);
 1090                         precision = rsbt;
 1091                         precision >>= tc_precexp;
 1092                         if (TIMESEL(&asbt, rsbt))
 1093                                 asbt += tc_tick_sbt;
 1094                         if (asbt <= SBT_MAX - rsbt)
 1095                                 asbt += rsbt;
 1096                         else
 1097                                 asbt = -1;
 1098                 } else
 1099                         asbt = -1;
 1100         } else
 1101                 asbt = -1;
 1102         seltdinit(td);
 1103         /* Iterate until the timeout expires or descriptors become ready. */
 1104         for (;;) {
 1105                 error = selscan(td, ibits, obits, nd);
 1106                 if (error || td->td_retval[0] != 0)
 1107                         break;
 1108                 error = seltdwait(td, asbt, precision);
 1109                 if (error)
 1110                         break;
 1111                 error = selrescan(td, ibits, obits);
 1112                 if (error || td->td_retval[0] != 0)
 1113                         break;
 1114         }
 1115         seltdclear(td);
 1116 
 1117 done:
 1118         /* select is not restarted after signals... */
 1119         if (error == ERESTART)
 1120                 error = EINTR;
 1121         if (error == EWOULDBLOCK)
 1122                 error = 0;
 1123 
 1124         /* swizzle bit order back, if necessary */
 1125         swizzle_fdset(obits[0]);
 1126         swizzle_fdset(obits[1]);
 1127         swizzle_fdset(obits[2]);
 1128 #undef swizzle_fdset
 1129 
 1130 #define putbits(name, x) \
 1131         if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
 1132                 error = error2;
 1133         if (error == 0) {
 1134                 int error2;
 1135 
 1136                 putbits(fd_in, 0);
 1137                 putbits(fd_ou, 1);
 1138                 putbits(fd_ex, 2);
 1139 #undef putbits
 1140         }
 1141         if (selbits != &s_selbits[0])
 1142                 free(selbits, M_SELECT);
 1143 
 1144         return (error);
 1145 }
 1146 /* 
 1147  * Convert a select bit set to poll flags.
 1148  *
 1149  * The backend always returns POLLHUP/POLLERR if appropriate and we
 1150  * return this as a set bit in any set.
 1151  */
 1152 static int select_flags[3] = {
 1153     POLLRDNORM | POLLHUP | POLLERR,
 1154     POLLWRNORM | POLLHUP | POLLERR,
 1155     POLLRDBAND | POLLERR
 1156 };
 1157 
 1158 /*
 1159  * Compute the fo_poll flags required for a fd given by the index and
 1160  * bit position in the fd_mask array.
 1161  */
 1162 static __inline int
 1163 selflags(fd_mask **ibits, int idx, fd_mask bit)
 1164 {
 1165         int flags;
 1166         int msk;
 1167 
 1168         flags = 0;
 1169         for (msk = 0; msk < 3; msk++) {
 1170                 if (ibits[msk] == NULL)
 1171                         continue;
 1172                 if ((ibits[msk][idx] & bit) == 0)
 1173                         continue;
 1174                 flags |= select_flags[msk];
 1175         }
 1176         return (flags);
 1177 }
 1178 
 1179 /*
 1180  * Set the appropriate output bits given a mask of fired events and the
 1181  * input bits originally requested.
 1182  */
 1183 static __inline int
 1184 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
 1185 {
 1186         int msk;
 1187         int n;
 1188 
 1189         n = 0;
 1190         for (msk = 0; msk < 3; msk++) {
 1191                 if ((events & select_flags[msk]) == 0)
 1192                         continue;
 1193                 if (ibits[msk] == NULL)
 1194                         continue;
 1195                 if ((ibits[msk][idx] & bit) == 0)
 1196                         continue;
 1197                 /*
 1198                  * XXX Check for a duplicate set.  This can occur because a
 1199                  * socket calls selrecord() twice for each poll() call
 1200                  * resulting in two selfds per real fd.  selrescan() will
 1201                  * call selsetbits twice as a result.
 1202                  */
 1203                 if ((obits[msk][idx] & bit) != 0)
 1204                         continue;
 1205                 obits[msk][idx] |= bit;
 1206                 n++;
 1207         }
 1208 
 1209         return (n);
 1210 }
 1211 
 1212 static __inline int
 1213 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp)
 1214 {
 1215         cap_rights_t rights;
 1216 
 1217         cap_rights_init(&rights, CAP_EVENT);
 1218 
 1219         return (fget_unlocked(fdp, fd, &rights, 0, fpp, NULL));
 1220 }
 1221 
 1222 /*
 1223  * Traverse the list of fds attached to this thread's seltd and check for
 1224  * completion.
 1225  */
 1226 static int
 1227 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
 1228 {
 1229         struct filedesc *fdp;
 1230         struct selinfo *si;
 1231         struct seltd *stp;
 1232         struct selfd *sfp;
 1233         struct selfd *sfn;
 1234         struct file *fp;
 1235         fd_mask bit;
 1236         int fd, ev, n, idx;
 1237         int error;
 1238 
 1239         fdp = td->td_proc->p_fd;
 1240         stp = td->td_sel;
 1241         n = 0;
 1242         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1243                 fd = (int)(uintptr_t)sfp->sf_cookie;
 1244                 si = sfp->sf_si;
 1245                 selfdfree(stp, sfp);
 1246                 /* If the selinfo wasn't cleared the event didn't fire. */
 1247                 if (si != NULL)
 1248                         continue;
 1249                 error = getselfd_cap(fdp, fd, &fp);
 1250                 if (error)
 1251                         return (error);
 1252                 idx = fd / NFDBITS;
 1253                 bit = (fd_mask)1 << (fd % NFDBITS);
 1254                 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
 1255                 fdrop(fp, td);
 1256                 if (ev != 0)
 1257                         n += selsetbits(ibits, obits, idx, bit, ev);
 1258         }
 1259         stp->st_flags = 0;
 1260         td->td_retval[0] = n;
 1261         return (0);
 1262 }
 1263 
 1264 /*
 1265  * Perform the initial filedescriptor scan and register ourselves with
 1266  * each selinfo.
 1267  */
 1268 static int
 1269 selscan(td, ibits, obits, nfd)
 1270         struct thread *td;
 1271         fd_mask **ibits, **obits;
 1272         int nfd;
 1273 {
 1274         struct filedesc *fdp;
 1275         struct file *fp;
 1276         fd_mask bit;
 1277         int ev, flags, end, fd;
 1278         int n, idx;
 1279         int error;
 1280 
 1281         fdp = td->td_proc->p_fd;
 1282         n = 0;
 1283         for (idx = 0, fd = 0; fd < nfd; idx++) {
 1284                 end = imin(fd + NFDBITS, nfd);
 1285                 for (bit = 1; fd < end; bit <<= 1, fd++) {
 1286                         /* Compute the list of events we're interested in. */
 1287                         flags = selflags(ibits, idx, bit);
 1288                         if (flags == 0)
 1289                                 continue;
 1290                         error = getselfd_cap(fdp, fd, &fp);
 1291                         if (error)
 1292                                 return (error);
 1293                         selfdalloc(td, (void *)(uintptr_t)fd);
 1294                         ev = fo_poll(fp, flags, td->td_ucred, td);
 1295                         fdrop(fp, td);
 1296                         if (ev != 0)
 1297                                 n += selsetbits(ibits, obits, idx, bit, ev);
 1298                 }
 1299         }
 1300 
 1301         td->td_retval[0] = n;
 1302         return (0);
 1303 }
 1304 
 1305 int
 1306 sys_poll(struct thread *td, struct poll_args *uap)
 1307 {
 1308         struct timespec ts, *tsp;
 1309 
 1310         if (uap->timeout != INFTIM) {
 1311                 if (uap->timeout < 0)
 1312                         return (EINVAL);
 1313                 ts.tv_sec = uap->timeout / 1000;
 1314                 ts.tv_nsec = (uap->timeout % 1000) * 1000000;
 1315                 tsp = &ts;
 1316         } else
 1317                 tsp = NULL;
 1318 
 1319         return (kern_poll(td, uap->fds, uap->nfds, tsp, NULL));
 1320 }
 1321 
 1322 int
 1323 kern_poll(struct thread *td, struct pollfd *fds, u_int nfds,
 1324     struct timespec *tsp, sigset_t *uset)
 1325 {
 1326         struct pollfd *bits;
 1327         struct pollfd smallbits[32];
 1328         sbintime_t sbt, precision, tmp;
 1329         time_t over;
 1330         struct timespec ts;
 1331         int error;
 1332         size_t ni;
 1333 
 1334         precision = 0;
 1335         if (tsp != NULL) {
 1336                 if (tsp->tv_sec < 0)
 1337                         return (EINVAL);
 1338                 if (tsp->tv_nsec < 0 || tsp->tv_nsec >= 1000000000)
 1339                         return (EINVAL);
 1340                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
 1341                         sbt = 0;
 1342                 else {
 1343                         ts = *tsp;
 1344                         if (ts.tv_sec > INT32_MAX / 2) {
 1345                                 over = ts.tv_sec - INT32_MAX / 2;
 1346                                 ts.tv_sec -= over;
 1347                         } else
 1348                                 over = 0;
 1349                         tmp = tstosbt(ts);
 1350                         precision = tmp;
 1351                         precision >>= tc_precexp;
 1352                         if (TIMESEL(&sbt, tmp))
 1353                                 sbt += tc_tick_sbt;
 1354                         sbt += tmp;
 1355                 }
 1356         } else
 1357                 sbt = -1;
 1358 
 1359         if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 
 1360                 return (EINVAL);
 1361         ni = nfds * sizeof(struct pollfd);
 1362         if (ni > sizeof(smallbits))
 1363                 bits = malloc(ni, M_TEMP, M_WAITOK);
 1364         else
 1365                 bits = smallbits;
 1366         error = copyin(fds, bits, ni);
 1367         if (error)
 1368                 goto done;
 1369 
 1370         if (uset != NULL) {
 1371                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
 1372                     &td->td_oldsigmask, 0);
 1373                 if (error)
 1374                         goto done;
 1375                 td->td_pflags |= TDP_OLDMASK;
 1376                 /*
 1377                  * Make sure that ast() is called on return to
 1378                  * usermode and TDP_OLDMASK is cleared, restoring old
 1379                  * sigmask.
 1380                  */
 1381                 thread_lock(td);
 1382                 td->td_flags |= TDF_ASTPENDING;
 1383                 thread_unlock(td);
 1384         }
 1385 
 1386         seltdinit(td);
 1387         /* Iterate until the timeout expires or descriptors become ready. */
 1388         for (;;) {
 1389                 error = pollscan(td, bits, nfds);
 1390                 if (error || td->td_retval[0] != 0)
 1391                         break;
 1392                 error = seltdwait(td, sbt, precision);
 1393                 if (error)
 1394                         break;
 1395                 error = pollrescan(td);
 1396                 if (error || td->td_retval[0] != 0)
 1397                         break;
 1398         }
 1399         seltdclear(td);
 1400 
 1401 done:
 1402         /* poll is not restarted after signals... */
 1403         if (error == ERESTART)
 1404                 error = EINTR;
 1405         if (error == EWOULDBLOCK)
 1406                 error = 0;
 1407         if (error == 0) {
 1408                 error = pollout(td, bits, fds, nfds);
 1409                 if (error)
 1410                         goto out;
 1411         }
 1412 out:
 1413         if (ni > sizeof(smallbits))
 1414                 free(bits, M_TEMP);
 1415         return (error);
 1416 }
 1417 
 1418 int
 1419 sys_ppoll(struct thread *td, struct ppoll_args *uap)
 1420 {
 1421         struct timespec ts, *tsp;
 1422         sigset_t set, *ssp;
 1423         int error;
 1424 
 1425         if (uap->ts != NULL) {
 1426                 error = copyin(uap->ts, &ts, sizeof(ts));
 1427                 if (error)
 1428                         return (error);
 1429                 tsp = &ts;
 1430         } else
 1431                 tsp = NULL;
 1432         if (uap->set != NULL) {
 1433                 error = copyin(uap->set, &set, sizeof(set));
 1434                 if (error)
 1435                         return (error);
 1436                 ssp = &set;
 1437         } else
 1438                 ssp = NULL;
 1439         /*
 1440          * fds is still a pointer to user space. kern_poll() will
 1441          * take care of copyin that array to the kernel space.
 1442          */
 1443 
 1444         return (kern_poll(td, uap->fds, uap->nfds, tsp, ssp));
 1445 }
 1446 
 1447 static int
 1448 pollrescan(struct thread *td)
 1449 {
 1450         struct seltd *stp;
 1451         struct selfd *sfp;
 1452         struct selfd *sfn;
 1453         struct selinfo *si;
 1454         struct filedesc *fdp;
 1455         struct file *fp;
 1456         struct pollfd *fd;
 1457 #ifdef CAPABILITIES
 1458         cap_rights_t rights;
 1459 #endif
 1460         int n;
 1461 
 1462         n = 0;
 1463         fdp = td->td_proc->p_fd;
 1464         stp = td->td_sel;
 1465         FILEDESC_SLOCK(fdp);
 1466         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1467                 fd = (struct pollfd *)sfp->sf_cookie;
 1468                 si = sfp->sf_si;
 1469                 selfdfree(stp, sfp);
 1470                 /* If the selinfo wasn't cleared the event didn't fire. */
 1471                 if (si != NULL)
 1472                         continue;
 1473                 fp = fdp->fd_ofiles[fd->fd].fde_file;
 1474 #ifdef CAPABILITIES
 1475                 if (fp == NULL ||
 1476                     cap_check(cap_rights(fdp, fd->fd),
 1477                     cap_rights_init(&rights, CAP_EVENT)) != 0)
 1478 #else
 1479                 if (fp == NULL)
 1480 #endif
 1481                 {
 1482                         fd->revents = POLLNVAL;
 1483                         n++;
 1484                         continue;
 1485                 }
 1486 
 1487                 /*
 1488                  * Note: backend also returns POLLHUP and
 1489                  * POLLERR if appropriate.
 1490                  */
 1491                 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
 1492                 if (fd->revents != 0)
 1493                         n++;
 1494         }
 1495         FILEDESC_SUNLOCK(fdp);
 1496         stp->st_flags = 0;
 1497         td->td_retval[0] = n;
 1498         return (0);
 1499 }
 1500 
 1501 
 1502 static int
 1503 pollout(td, fds, ufds, nfd)
 1504         struct thread *td;
 1505         struct pollfd *fds;
 1506         struct pollfd *ufds;
 1507         u_int nfd;
 1508 {
 1509         int error = 0;
 1510         u_int i = 0;
 1511         u_int n = 0;
 1512 
 1513         for (i = 0; i < nfd; i++) {
 1514                 error = copyout(&fds->revents, &ufds->revents,
 1515                     sizeof(ufds->revents));
 1516                 if (error)
 1517                         return (error);
 1518                 if (fds->revents != 0)
 1519                         n++;
 1520                 fds++;
 1521                 ufds++;
 1522         }
 1523         td->td_retval[0] = n;
 1524         return (0);
 1525 }
 1526 
 1527 static int
 1528 pollscan(td, fds, nfd)
 1529         struct thread *td;
 1530         struct pollfd *fds;
 1531         u_int nfd;
 1532 {
 1533         struct filedesc *fdp = td->td_proc->p_fd;
 1534         struct file *fp;
 1535 #ifdef CAPABILITIES
 1536         cap_rights_t rights;
 1537 #endif
 1538         int i, n = 0;
 1539 
 1540         FILEDESC_SLOCK(fdp);
 1541         for (i = 0; i < nfd; i++, fds++) {
 1542                 if (fds->fd > fdp->fd_lastfile) {
 1543                         fds->revents = POLLNVAL;
 1544                         n++;
 1545                 } else if (fds->fd < 0) {
 1546                         fds->revents = 0;
 1547                 } else {
 1548                         fp = fdp->fd_ofiles[fds->fd].fde_file;
 1549 #ifdef CAPABILITIES
 1550                         if (fp == NULL ||
 1551                             cap_check(cap_rights(fdp, fds->fd),
 1552                             cap_rights_init(&rights, CAP_EVENT)) != 0)
 1553 #else
 1554                         if (fp == NULL)
 1555 #endif
 1556                         {
 1557                                 fds->revents = POLLNVAL;
 1558                                 n++;
 1559                         } else {
 1560                                 /*
 1561                                  * Note: backend also returns POLLHUP and
 1562                                  * POLLERR if appropriate.
 1563                                  */
 1564                                 selfdalloc(td, fds);
 1565                                 fds->revents = fo_poll(fp, fds->events,
 1566                                     td->td_ucred, td);
 1567                                 /*
 1568                                  * POSIX requires POLLOUT to be never
 1569                                  * set simultaneously with POLLHUP.
 1570                                  */
 1571                                 if ((fds->revents & POLLHUP) != 0)
 1572                                         fds->revents &= ~POLLOUT;
 1573 
 1574                                 if (fds->revents != 0)
 1575                                         n++;
 1576                         }
 1577                 }
 1578         }
 1579         FILEDESC_SUNLOCK(fdp);
 1580         td->td_retval[0] = n;
 1581         return (0);
 1582 }
 1583 
 1584 /*
 1585  * OpenBSD poll system call.
 1586  *
 1587  * XXX this isn't quite a true representation..  OpenBSD uses select ops.
 1588  */
 1589 #ifndef _SYS_SYSPROTO_H_
 1590 struct openbsd_poll_args {
 1591         struct pollfd *fds;
 1592         u_int   nfds;
 1593         int     timeout;
 1594 };
 1595 #endif
 1596 int
 1597 sys_openbsd_poll(td, uap)
 1598         register struct thread *td;
 1599         register struct openbsd_poll_args *uap;
 1600 {
 1601         return (sys_poll(td, (struct poll_args *)uap));
 1602 }
 1603 
 1604 /*
 1605  * XXX This was created specifically to support netncp and netsmb.  This
 1606  * allows the caller to specify a socket to wait for events on.  It returns
 1607  * 0 if any events matched and an error otherwise.  There is no way to
 1608  * determine which events fired.
 1609  */
 1610 int
 1611 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
 1612 {
 1613         struct timeval rtv;
 1614         sbintime_t asbt, precision, rsbt;
 1615         int error;
 1616 
 1617         precision = 0;  /* stupid gcc! */
 1618         if (tvp != NULL) {
 1619                 rtv = *tvp;
 1620                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 || 
 1621                     rtv.tv_usec >= 1000000)
 1622                         return (EINVAL);
 1623                 if (!timevalisset(&rtv))
 1624                         asbt = 0;
 1625                 else if (rtv.tv_sec <= INT32_MAX) {
 1626                         rsbt = tvtosbt(rtv);
 1627                         precision = rsbt;
 1628                         precision >>= tc_precexp;
 1629                         if (TIMESEL(&asbt, rsbt))
 1630                                 asbt += tc_tick_sbt;
 1631                         if (asbt <= SBT_MAX - rsbt)
 1632                                 asbt += rsbt;
 1633                         else
 1634                                 asbt = -1;
 1635                 } else
 1636                         asbt = -1;
 1637         } else
 1638                 asbt = -1;
 1639         seltdinit(td);
 1640         /*
 1641          * Iterate until the timeout expires or the socket becomes ready.
 1642          */
 1643         for (;;) {
 1644                 selfdalloc(td, NULL);
 1645                 error = sopoll(so, events, NULL, td);
 1646                 /* error here is actually the ready events. */
 1647                 if (error)
 1648                         return (0);
 1649                 error = seltdwait(td, asbt, precision);
 1650                 if (error)
 1651                         break;
 1652         }
 1653         seltdclear(td);
 1654         /* XXX Duplicates ncp/smb behavior. */
 1655         if (error == ERESTART)
 1656                 error = 0;
 1657         return (error);
 1658 }
 1659 
 1660 /*
 1661  * Preallocate two selfds associated with 'cookie'.  Some fo_poll routines
 1662  * have two select sets, one for read and another for write.
 1663  */
 1664 static void
 1665 selfdalloc(struct thread *td, void *cookie)
 1666 {
 1667         struct seltd *stp;
 1668 
 1669         stp = td->td_sel;
 1670         if (stp->st_free1 == NULL)
 1671                 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1672         stp->st_free1->sf_td = stp;
 1673         stp->st_free1->sf_cookie = cookie;
 1674         if (stp->st_free2 == NULL)
 1675                 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1676         stp->st_free2->sf_td = stp;
 1677         stp->st_free2->sf_cookie = cookie;
 1678 }
 1679 
 1680 static void
 1681 selfdfree(struct seltd *stp, struct selfd *sfp)
 1682 {
 1683         STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
 1684         mtx_lock(sfp->sf_mtx);
 1685         if (sfp->sf_si)
 1686                 TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
 1687         mtx_unlock(sfp->sf_mtx);
 1688         uma_zfree(selfd_zone, sfp);
 1689 }
 1690 
 1691 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */
 1692 void
 1693 seldrain(sip)
 1694         struct selinfo *sip;
 1695 {
 1696 
 1697         /*
 1698          * This feature is already provided by doselwakeup(), thus it is
 1699          * enough to go for it.
 1700          * Eventually, the context, should take care to avoid races
 1701          * between thread calling select()/poll() and file descriptor
 1702          * detaching, but, again, the races are just the same as
 1703          * selwakeup().
 1704          */
 1705         doselwakeup(sip, -1);
 1706 }
 1707 
 1708 /*
 1709  * Record a select request.
 1710  */
 1711 void
 1712 selrecord(selector, sip)
 1713         struct thread *selector;
 1714         struct selinfo *sip;
 1715 {
 1716         struct selfd *sfp;
 1717         struct seltd *stp;
 1718         struct mtx *mtxp;
 1719 
 1720         stp = selector->td_sel;
 1721         /*
 1722          * Don't record when doing a rescan.
 1723          */
 1724         if (stp->st_flags & SELTD_RESCAN)
 1725                 return;
 1726         /*
 1727          * Grab one of the preallocated descriptors.
 1728          */
 1729         sfp = NULL;
 1730         if ((sfp = stp->st_free1) != NULL)
 1731                 stp->st_free1 = NULL;
 1732         else if ((sfp = stp->st_free2) != NULL)
 1733                 stp->st_free2 = NULL;
 1734         else
 1735                 panic("selrecord: No free selfd on selq");
 1736         mtxp = sip->si_mtx;
 1737         if (mtxp == NULL)
 1738                 mtxp = mtx_pool_find(mtxpool_select, sip);
 1739         /*
 1740          * Initialize the sfp and queue it in the thread.
 1741          */
 1742         sfp->sf_si = sip;
 1743         sfp->sf_mtx = mtxp;
 1744         STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
 1745         /*
 1746          * Now that we've locked the sip, check for initialization.
 1747          */
 1748         mtx_lock(mtxp);
 1749         if (sip->si_mtx == NULL) {
 1750                 sip->si_mtx = mtxp;
 1751                 TAILQ_INIT(&sip->si_tdlist);
 1752         }
 1753         /*
 1754          * Add this thread to the list of selfds listening on this selinfo.
 1755          */
 1756         TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
 1757         mtx_unlock(sip->si_mtx);
 1758 }
 1759 
 1760 /* Wake up a selecting thread. */
 1761 void
 1762 selwakeup(sip)
 1763         struct selinfo *sip;
 1764 {
 1765         doselwakeup(sip, -1);
 1766 }
 1767 
 1768 /* Wake up a selecting thread, and set its priority. */
 1769 void
 1770 selwakeuppri(sip, pri)
 1771         struct selinfo *sip;
 1772         int pri;
 1773 {
 1774         doselwakeup(sip, pri);
 1775 }
 1776 
 1777 /*
 1778  * Do a wakeup when a selectable event occurs.
 1779  */
 1780 static void
 1781 doselwakeup(sip, pri)
 1782         struct selinfo *sip;
 1783         int pri;
 1784 {
 1785         struct selfd *sfp;
 1786         struct selfd *sfn;
 1787         struct seltd *stp;
 1788 
 1789         /* If it's not initialized there can't be any waiters. */
 1790         if (sip->si_mtx == NULL)
 1791                 return;
 1792         /*
 1793          * Locking the selinfo locks all selfds associated with it.
 1794          */
 1795         mtx_lock(sip->si_mtx);
 1796         TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
 1797                 /*
 1798                  * Once we remove this sfp from the list and clear the
 1799                  * sf_si seltdclear will know to ignore this si.
 1800                  */
 1801                 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
 1802                 sfp->sf_si = NULL;
 1803                 stp = sfp->sf_td;
 1804                 mtx_lock(&stp->st_mtx);
 1805                 stp->st_flags |= SELTD_PENDING;
 1806                 cv_broadcastpri(&stp->st_wait, pri);
 1807                 mtx_unlock(&stp->st_mtx);
 1808         }
 1809         mtx_unlock(sip->si_mtx);
 1810 }
 1811 
 1812 static void
 1813 seltdinit(struct thread *td)
 1814 {
 1815         struct seltd *stp;
 1816 
 1817         if ((stp = td->td_sel) != NULL)
 1818                 goto out;
 1819         td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
 1820         mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
 1821         cv_init(&stp->st_wait, "select");
 1822 out:
 1823         stp->st_flags = 0;
 1824         STAILQ_INIT(&stp->st_selq);
 1825 }
 1826 
 1827 static int
 1828 seltdwait(struct thread *td, sbintime_t sbt, sbintime_t precision)
 1829 {
 1830         struct seltd *stp;
 1831         int error;
 1832 
 1833         stp = td->td_sel;
 1834         /*
 1835          * An event of interest may occur while we do not hold the seltd
 1836          * locked so check the pending flag before we sleep.
 1837          */
 1838         mtx_lock(&stp->st_mtx);
 1839         /*
 1840          * Any further calls to selrecord will be a rescan.
 1841          */
 1842         stp->st_flags |= SELTD_RESCAN;
 1843         if (stp->st_flags & SELTD_PENDING) {
 1844                 mtx_unlock(&stp->st_mtx);
 1845                 return (0);
 1846         }
 1847         if (sbt == 0)
 1848                 error = EWOULDBLOCK;
 1849         else if (sbt != -1)
 1850                 error = cv_timedwait_sig_sbt(&stp->st_wait, &stp->st_mtx,
 1851                     sbt, precision, C_ABSOLUTE);
 1852         else
 1853                 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
 1854         mtx_unlock(&stp->st_mtx);
 1855 
 1856         return (error);
 1857 }
 1858 
 1859 void
 1860 seltdfini(struct thread *td)
 1861 {
 1862         struct seltd *stp;
 1863 
 1864         stp = td->td_sel;
 1865         if (stp == NULL)
 1866                 return;
 1867         if (stp->st_free1)
 1868                 uma_zfree(selfd_zone, stp->st_free1);
 1869         if (stp->st_free2)
 1870                 uma_zfree(selfd_zone, stp->st_free2);
 1871         td->td_sel = NULL;
 1872         free(stp, M_SELECT);
 1873 }
 1874 
 1875 /*
 1876  * Remove the references to the thread from all of the objects we were
 1877  * polling.
 1878  */
 1879 static void
 1880 seltdclear(struct thread *td)
 1881 {
 1882         struct seltd *stp;
 1883         struct selfd *sfp;
 1884         struct selfd *sfn;
 1885 
 1886         stp = td->td_sel;
 1887         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
 1888                 selfdfree(stp, sfp);
 1889         stp->st_flags = 0;
 1890 }
 1891 
 1892 static void selectinit(void *);
 1893 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
 1894 static void
 1895 selectinit(void *dummy __unused)
 1896 {
 1897 
 1898         selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
 1899             NULL, NULL, UMA_ALIGN_PTR, 0);
 1900         mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
 1901 }

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