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: releng/10.1/sys/kern/sys_generic.c 268338 2014-07-06 22:54:17Z mjg $");
   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/capability.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 int iosize_max_clamp = 1;
   79 SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW,
   80     &iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX");
   81 int devfs_iosize_max_clamp = 1;
   82 SYSCTL_INT(_debug, OID_AUTO, devfs_iosize_max_clamp, CTLFLAG_RW,
   83     &devfs_iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX for devices");
   84 
   85 /*
   86  * Assert that the return value of read(2) and write(2) syscalls fits
   87  * into a register.  If not, an architecture will need to provide the
   88  * usermode wrappers to reconstruct the result.
   89  */
   90 CTASSERT(sizeof(register_t) >= sizeof(size_t));
   91 
   92 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer");
   93 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer");
   94 MALLOC_DEFINE(M_IOV, "iov", "large iov's");
   95 
   96 static int      pollout(struct thread *, struct pollfd *, struct pollfd *,
   97                     u_int);
   98 static int      pollscan(struct thread *, struct pollfd *, u_int);
   99 static int      pollrescan(struct thread *);
  100 static int      selscan(struct thread *, fd_mask **, fd_mask **, int);
  101 static int      selrescan(struct thread *, fd_mask **, fd_mask **);
  102 static void     selfdalloc(struct thread *, void *);
  103 static void     selfdfree(struct seltd *, struct selfd *);
  104 static int      dofileread(struct thread *, int, struct file *, struct uio *,
  105                     off_t, int);
  106 static int      dofilewrite(struct thread *, int, struct file *, struct uio *,
  107                     off_t, int);
  108 static void     doselwakeup(struct selinfo *, int);
  109 static void     seltdinit(struct thread *);
  110 static int      seltdwait(struct thread *, sbintime_t, sbintime_t);
  111 static void     seltdclear(struct thread *);
  112 
  113 /*
  114  * One seltd per-thread allocated on demand as needed.
  115  *
  116  *      t - protected by st_mtx
  117  *      k - Only accessed by curthread or read-only
  118  */
  119 struct seltd {
  120         STAILQ_HEAD(, selfd)    st_selq;        /* (k) List of selfds. */
  121         struct selfd            *st_free1;      /* (k) free fd for read set. */
  122         struct selfd            *st_free2;      /* (k) free fd for write set. */
  123         struct mtx              st_mtx;         /* Protects struct seltd */
  124         struct cv               st_wait;        /* (t) Wait channel. */
  125         int                     st_flags;       /* (t) SELTD_ flags. */
  126 };
  127 
  128 #define SELTD_PENDING   0x0001                  /* We have pending events. */
  129 #define SELTD_RESCAN    0x0002                  /* Doing a rescan. */
  130 
  131 /*
  132  * One selfd allocated per-thread per-file-descriptor.
  133  *      f - protected by sf_mtx
  134  */
  135 struct selfd {
  136         STAILQ_ENTRY(selfd)     sf_link;        /* (k) fds owned by this td. */
  137         TAILQ_ENTRY(selfd)      sf_threads;     /* (f) fds on this selinfo. */
  138         struct selinfo          *sf_si;         /* (f) selinfo when linked. */
  139         struct mtx              *sf_mtx;        /* Pointer to selinfo mtx. */
  140         struct seltd            *sf_td;         /* (k) owning seltd. */
  141         void                    *sf_cookie;     /* (k) fd or pollfd. */
  142 };
  143 
  144 static uma_zone_t selfd_zone;
  145 static struct mtx_pool *mtxpool_select;
  146 
  147 #ifndef _SYS_SYSPROTO_H_
  148 struct read_args {
  149         int     fd;
  150         void    *buf;
  151         size_t  nbyte;
  152 };
  153 #endif
  154 int
  155 sys_read(td, uap)
  156         struct thread *td;
  157         struct read_args *uap;
  158 {
  159         struct uio auio;
  160         struct iovec aiov;
  161         int error;
  162 
  163         if (uap->nbyte > IOSIZE_MAX)
  164                 return (EINVAL);
  165         aiov.iov_base = uap->buf;
  166         aiov.iov_len = uap->nbyte;
  167         auio.uio_iov = &aiov;
  168         auio.uio_iovcnt = 1;
  169         auio.uio_resid = uap->nbyte;
  170         auio.uio_segflg = UIO_USERSPACE;
  171         error = kern_readv(td, uap->fd, &auio);
  172         return(error);
  173 }
  174 
  175 /*
  176  * Positioned read system call
  177  */
  178 #ifndef _SYS_SYSPROTO_H_
  179 struct pread_args {
  180         int     fd;
  181         void    *buf;
  182         size_t  nbyte;
  183         int     pad;
  184         off_t   offset;
  185 };
  186 #endif
  187 int
  188 sys_pread(td, uap)
  189         struct thread *td;
  190         struct pread_args *uap;
  191 {
  192         struct uio auio;
  193         struct iovec aiov;
  194         int error;
  195 
  196         if (uap->nbyte > IOSIZE_MAX)
  197                 return (EINVAL);
  198         aiov.iov_base = uap->buf;
  199         aiov.iov_len = uap->nbyte;
  200         auio.uio_iov = &aiov;
  201         auio.uio_iovcnt = 1;
  202         auio.uio_resid = uap->nbyte;
  203         auio.uio_segflg = UIO_USERSPACE;
  204         error = kern_preadv(td, uap->fd, &auio, uap->offset);
  205         return(error);
  206 }
  207 
  208 int
  209 freebsd6_pread(td, uap)
  210         struct thread *td;
  211         struct freebsd6_pread_args *uap;
  212 {
  213         struct pread_args oargs;
  214 
  215         oargs.fd = uap->fd;
  216         oargs.buf = uap->buf;
  217         oargs.nbyte = uap->nbyte;
  218         oargs.offset = uap->offset;
  219         return (sys_pread(td, &oargs));
  220 }
  221 
  222 /*
  223  * Scatter read system call.
  224  */
  225 #ifndef _SYS_SYSPROTO_H_
  226 struct readv_args {
  227         int     fd;
  228         struct  iovec *iovp;
  229         u_int   iovcnt;
  230 };
  231 #endif
  232 int
  233 sys_readv(struct thread *td, struct readv_args *uap)
  234 {
  235         struct uio *auio;
  236         int error;
  237 
  238         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  239         if (error)
  240                 return (error);
  241         error = kern_readv(td, uap->fd, auio);
  242         free(auio, M_IOV);
  243         return (error);
  244 }
  245 
  246 int
  247 kern_readv(struct thread *td, int fd, struct uio *auio)
  248 {
  249         struct file *fp;
  250         cap_rights_t rights;
  251         int error;
  252 
  253         error = fget_read(td, fd, cap_rights_init(&rights, CAP_READ), &fp);
  254         if (error)
  255                 return (error);
  256         error = dofileread(td, fd, fp, auio, (off_t)-1, 0);
  257         fdrop(fp, td);
  258         return (error);
  259 }
  260 
  261 /*
  262  * Scatter positioned read system call.
  263  */
  264 #ifndef _SYS_SYSPROTO_H_
  265 struct preadv_args {
  266         int     fd;
  267         struct  iovec *iovp;
  268         u_int   iovcnt;
  269         off_t   offset;
  270 };
  271 #endif
  272 int
  273 sys_preadv(struct thread *td, struct preadv_args *uap)
  274 {
  275         struct uio *auio;
  276         int error;
  277 
  278         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  279         if (error)
  280                 return (error);
  281         error = kern_preadv(td, uap->fd, auio, uap->offset);
  282         free(auio, M_IOV);
  283         return (error);
  284 }
  285 
  286 int
  287 kern_preadv(td, fd, auio, offset)
  288         struct thread *td;
  289         int fd;
  290         struct uio *auio;
  291         off_t offset;
  292 {
  293         struct file *fp;
  294         cap_rights_t rights;
  295         int error;
  296 
  297         error = fget_read(td, fd, cap_rights_init(&rights, CAP_PREAD), &fp);
  298         if (error)
  299                 return (error);
  300         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  301                 error = ESPIPE;
  302         else if (offset < 0 && fp->f_vnode->v_type != VCHR)
  303                 error = EINVAL;
  304         else
  305                 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET);
  306         fdrop(fp, td);
  307         return (error);
  308 }
  309 
  310 /*
  311  * Common code for readv and preadv that reads data in
  312  * from a file using the passed in uio, offset, and flags.
  313  */
  314 static int
  315 dofileread(td, fd, fp, auio, offset, flags)
  316         struct thread *td;
  317         int fd;
  318         struct file *fp;
  319         struct uio *auio;
  320         off_t offset;
  321         int flags;
  322 {
  323         ssize_t cnt;
  324         int error;
  325 #ifdef KTRACE
  326         struct uio *ktruio = NULL;
  327 #endif
  328 
  329         /* Finish zero length reads right here */
  330         if (auio->uio_resid == 0) {
  331                 td->td_retval[0] = 0;
  332                 return(0);
  333         }
  334         auio->uio_rw = UIO_READ;
  335         auio->uio_offset = offset;
  336         auio->uio_td = td;
  337 #ifdef KTRACE
  338         if (KTRPOINT(td, KTR_GENIO)) 
  339                 ktruio = cloneuio(auio);
  340 #endif
  341         cnt = auio->uio_resid;
  342         if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) {
  343                 if (auio->uio_resid != cnt && (error == ERESTART ||
  344                     error == EINTR || error == EWOULDBLOCK))
  345                         error = 0;
  346         }
  347         cnt -= auio->uio_resid;
  348 #ifdef KTRACE
  349         if (ktruio != NULL) {
  350                 ktruio->uio_resid = cnt;
  351                 ktrgenio(fd, UIO_READ, ktruio, error);
  352         }
  353 #endif
  354         td->td_retval[0] = cnt;
  355         return (error);
  356 }
  357 
  358 #ifndef _SYS_SYSPROTO_H_
  359 struct write_args {
  360         int     fd;
  361         const void *buf;
  362         size_t  nbyte;
  363 };
  364 #endif
  365 int
  366 sys_write(td, uap)
  367         struct thread *td;
  368         struct write_args *uap;
  369 {
  370         struct uio auio;
  371         struct iovec aiov;
  372         int error;
  373 
  374         if (uap->nbyte > IOSIZE_MAX)
  375                 return (EINVAL);
  376         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  377         aiov.iov_len = uap->nbyte;
  378         auio.uio_iov = &aiov;
  379         auio.uio_iovcnt = 1;
  380         auio.uio_resid = uap->nbyte;
  381         auio.uio_segflg = UIO_USERSPACE;
  382         error = kern_writev(td, uap->fd, &auio);
  383         return(error);
  384 }
  385 
  386 /*
  387  * Positioned write system call.
  388  */
  389 #ifndef _SYS_SYSPROTO_H_
  390 struct pwrite_args {
  391         int     fd;
  392         const void *buf;
  393         size_t  nbyte;
  394         int     pad;
  395         off_t   offset;
  396 };
  397 #endif
  398 int
  399 sys_pwrite(td, uap)
  400         struct thread *td;
  401         struct pwrite_args *uap;
  402 {
  403         struct uio auio;
  404         struct iovec aiov;
  405         int error;
  406 
  407         if (uap->nbyte > IOSIZE_MAX)
  408                 return (EINVAL);
  409         aiov.iov_base = (void *)(uintptr_t)uap->buf;
  410         aiov.iov_len = uap->nbyte;
  411         auio.uio_iov = &aiov;
  412         auio.uio_iovcnt = 1;
  413         auio.uio_resid = uap->nbyte;
  414         auio.uio_segflg = UIO_USERSPACE;
  415         error = kern_pwritev(td, uap->fd, &auio, uap->offset);
  416         return(error);
  417 }
  418 
  419 int
  420 freebsd6_pwrite(td, uap)
  421         struct thread *td;
  422         struct freebsd6_pwrite_args *uap;
  423 {
  424         struct pwrite_args oargs;
  425 
  426         oargs.fd = uap->fd;
  427         oargs.buf = uap->buf;
  428         oargs.nbyte = uap->nbyte;
  429         oargs.offset = uap->offset;
  430         return (sys_pwrite(td, &oargs));
  431 }
  432 
  433 /*
  434  * Gather write system call.
  435  */
  436 #ifndef _SYS_SYSPROTO_H_
  437 struct writev_args {
  438         int     fd;
  439         struct  iovec *iovp;
  440         u_int   iovcnt;
  441 };
  442 #endif
  443 int
  444 sys_writev(struct thread *td, struct writev_args *uap)
  445 {
  446         struct uio *auio;
  447         int error;
  448 
  449         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  450         if (error)
  451                 return (error);
  452         error = kern_writev(td, uap->fd, auio);
  453         free(auio, M_IOV);
  454         return (error);
  455 }
  456 
  457 int
  458 kern_writev(struct thread *td, int fd, struct uio *auio)
  459 {
  460         struct file *fp;
  461         cap_rights_t rights;
  462         int error;
  463 
  464         error = fget_write(td, fd, cap_rights_init(&rights, CAP_WRITE), &fp);
  465         if (error)
  466                 return (error);
  467         error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0);
  468         fdrop(fp, td);
  469         return (error);
  470 }
  471 
  472 /*
  473  * Gather positioned write system call.
  474  */
  475 #ifndef _SYS_SYSPROTO_H_
  476 struct pwritev_args {
  477         int     fd;
  478         struct  iovec *iovp;
  479         u_int   iovcnt;
  480         off_t   offset;
  481 };
  482 #endif
  483 int
  484 sys_pwritev(struct thread *td, struct pwritev_args *uap)
  485 {
  486         struct uio *auio;
  487         int error;
  488 
  489         error = copyinuio(uap->iovp, uap->iovcnt, &auio);
  490         if (error)
  491                 return (error);
  492         error = kern_pwritev(td, uap->fd, auio, uap->offset);
  493         free(auio, M_IOV);
  494         return (error);
  495 }
  496 
  497 int
  498 kern_pwritev(td, fd, auio, offset)
  499         struct thread *td;
  500         struct uio *auio;
  501         int fd;
  502         off_t offset;
  503 {
  504         struct file *fp;
  505         cap_rights_t rights;
  506         int error;
  507 
  508         error = fget_write(td, fd, cap_rights_init(&rights, CAP_PWRITE), &fp);
  509         if (error)
  510                 return (error);
  511         if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
  512                 error = ESPIPE;
  513         else if (offset < 0 && fp->f_vnode->v_type != VCHR)
  514                 error = EINVAL;
  515         else
  516                 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET);
  517         fdrop(fp, td);
  518         return (error);
  519 }
  520 
  521 /*
  522  * Common code for writev and pwritev that writes data to
  523  * a file using the passed in uio, offset, and flags.
  524  */
  525 static int
  526 dofilewrite(td, fd, fp, auio, offset, flags)
  527         struct thread *td;
  528         int fd;
  529         struct file *fp;
  530         struct uio *auio;
  531         off_t offset;
  532         int flags;
  533 {
  534         ssize_t cnt;
  535         int error;
  536 #ifdef KTRACE
  537         struct uio *ktruio = NULL;
  538 #endif
  539 
  540         auio->uio_rw = UIO_WRITE;
  541         auio->uio_td = td;
  542         auio->uio_offset = offset;
  543 #ifdef KTRACE
  544         if (KTRPOINT(td, KTR_GENIO))
  545                 ktruio = cloneuio(auio);
  546 #endif
  547         cnt = auio->uio_resid;
  548         if (fp->f_type == DTYPE_VNODE &&
  549             (fp->f_vnread_flags & FDEVFS_VNODE) == 0)
  550                 bwillwrite();
  551         if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) {
  552                 if (auio->uio_resid != cnt && (error == ERESTART ||
  553                     error == EINTR || error == EWOULDBLOCK))
  554                         error = 0;
  555                 /* Socket layer is responsible for issuing SIGPIPE. */
  556                 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) {
  557                         PROC_LOCK(td->td_proc);
  558                         tdsignal(td, SIGPIPE);
  559                         PROC_UNLOCK(td->td_proc);
  560                 }
  561         }
  562         cnt -= auio->uio_resid;
  563 #ifdef KTRACE
  564         if (ktruio != NULL) {
  565                 ktruio->uio_resid = cnt;
  566                 ktrgenio(fd, UIO_WRITE, ktruio, error);
  567         }
  568 #endif
  569         td->td_retval[0] = cnt;
  570         return (error);
  571 }
  572 
  573 /*
  574  * Truncate a file given a file descriptor.
  575  *
  576  * Can't use fget_write() here, since must return EINVAL and not EBADF if the
  577  * descriptor isn't writable.
  578  */
  579 int
  580 kern_ftruncate(td, fd, length)
  581         struct thread *td;
  582         int fd;
  583         off_t length;
  584 {
  585         struct file *fp;
  586         cap_rights_t rights;
  587         int error;
  588 
  589         AUDIT_ARG_FD(fd);
  590         if (length < 0)
  591                 return (EINVAL);
  592         error = fget(td, fd, cap_rights_init(&rights, CAP_FTRUNCATE), &fp);
  593         if (error)
  594                 return (error);
  595         AUDIT_ARG_FILE(td->td_proc, fp);
  596         if (!(fp->f_flag & FWRITE)) {
  597                 fdrop(fp, td);
  598                 return (EINVAL);
  599         }
  600         error = fo_truncate(fp, length, td->td_ucred, td);
  601         fdrop(fp, td);
  602         return (error);
  603 }
  604 
  605 #ifndef _SYS_SYSPROTO_H_
  606 struct ftruncate_args {
  607         int     fd;
  608         int     pad;
  609         off_t   length;
  610 };
  611 #endif
  612 int
  613 sys_ftruncate(td, uap)
  614         struct thread *td;
  615         struct ftruncate_args *uap;
  616 {
  617 
  618         return (kern_ftruncate(td, uap->fd, uap->length));
  619 }
  620 
  621 #if defined(COMPAT_43)
  622 #ifndef _SYS_SYSPROTO_H_
  623 struct oftruncate_args {
  624         int     fd;
  625         long    length;
  626 };
  627 #endif
  628 int
  629 oftruncate(td, uap)
  630         struct thread *td;
  631         struct oftruncate_args *uap;
  632 {
  633 
  634         return (kern_ftruncate(td, uap->fd, uap->length));
  635 }
  636 #endif /* COMPAT_43 */
  637 
  638 #ifndef _SYS_SYSPROTO_H_
  639 struct ioctl_args {
  640         int     fd;
  641         u_long  com;
  642         caddr_t data;
  643 };
  644 #endif
  645 /* ARGSUSED */
  646 int
  647 sys_ioctl(struct thread *td, struct ioctl_args *uap)
  648 {
  649         u_long com;
  650         int arg, error;
  651         u_int size;
  652         caddr_t data;
  653 
  654         if (uap->com > 0xffffffff) {
  655                 printf(
  656                     "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
  657                     td->td_proc->p_pid, td->td_name, uap->com);
  658                 uap->com &= 0xffffffff;
  659         }
  660         com = uap->com;
  661 
  662         /*
  663          * Interpret high order word to find amount of data to be
  664          * copied to/from the user's address space.
  665          */
  666         size = IOCPARM_LEN(com);
  667         if ((size > IOCPARM_MAX) ||
  668             ((com & (IOC_VOID  | IOC_IN | IOC_OUT)) == 0) ||
  669 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
  670             ((com & IOC_OUT) && size == 0) ||
  671 #else
  672             ((com & (IOC_IN | IOC_OUT)) && size == 0) ||
  673 #endif
  674             ((com & IOC_VOID) && size > 0 && size != sizeof(int)))
  675                 return (ENOTTY);
  676 
  677         if (size > 0) {
  678                 if (com & IOC_VOID) {
  679                         /* Integer argument. */
  680                         arg = (intptr_t)uap->data;
  681                         data = (void *)&arg;
  682                         size = 0;
  683                 } else
  684                         data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
  685         } else
  686                 data = (void *)&uap->data;
  687         if (com & IOC_IN) {
  688                 error = copyin(uap->data, data, (u_int)size);
  689                 if (error) {
  690                         if (size > 0)
  691                                 free(data, M_IOCTLOPS);
  692                         return (error);
  693                 }
  694         } else if (com & IOC_OUT) {
  695                 /*
  696                  * Zero the buffer so the user always
  697                  * gets back something deterministic.
  698                  */
  699                 bzero(data, size);
  700         }
  701 
  702         error = kern_ioctl(td, uap->fd, com, data);
  703 
  704         if (error == 0 && (com & IOC_OUT))
  705                 error = copyout(data, uap->data, (u_int)size);
  706 
  707         if (size > 0)
  708                 free(data, M_IOCTLOPS);
  709         return (error);
  710 }
  711 
  712 int
  713 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
  714 {
  715         struct file *fp;
  716         struct filedesc *fdp;
  717 #ifndef CAPABILITIES
  718         cap_rights_t rights;
  719 #endif
  720         int error, tmp, locked;
  721 
  722         AUDIT_ARG_FD(fd);
  723         AUDIT_ARG_CMD(com);
  724 
  725         fdp = td->td_proc->p_fd;
  726 
  727         switch (com) {
  728         case FIONCLEX:
  729         case FIOCLEX:
  730                 FILEDESC_XLOCK(fdp);
  731                 locked = LA_XLOCKED;
  732                 break;
  733         default:
  734 #ifdef CAPABILITIES
  735                 FILEDESC_SLOCK(fdp);
  736                 locked = LA_SLOCKED;
  737 #else
  738                 locked = LA_UNLOCKED;
  739 #endif
  740                 break;
  741         }
  742 
  743 #ifdef CAPABILITIES
  744         if ((fp = fget_locked(fdp, fd)) == NULL) {
  745                 error = EBADF;
  746                 goto out;
  747         }
  748         if ((error = cap_ioctl_check(fdp, fd, com)) != 0) {
  749                 fp = NULL;      /* fhold() was not called yet */
  750                 goto out;
  751         }
  752         fhold(fp);
  753         if (locked == LA_SLOCKED) {
  754                 FILEDESC_SUNLOCK(fdp);
  755                 locked = LA_UNLOCKED;
  756         }
  757 #else
  758         error = fget(td, fd, cap_rights_init(&rights, CAP_IOCTL), &fp);
  759         if (error != 0) {
  760                 fp = NULL;
  761                 goto out;
  762         }
  763 #endif
  764         if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
  765                 error = EBADF;
  766                 goto out;
  767         }
  768 
  769         switch (com) {
  770         case FIONCLEX:
  771                 fdp->fd_ofiles[fd].fde_flags &= ~UF_EXCLOSE;
  772                 goto out;
  773         case FIOCLEX:
  774                 fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE;
  775                 goto out;
  776         case FIONBIO:
  777                 if ((tmp = *(int *)data))
  778                         atomic_set_int(&fp->f_flag, FNONBLOCK);
  779                 else
  780                         atomic_clear_int(&fp->f_flag, FNONBLOCK);
  781                 data = (void *)&tmp;
  782                 break;
  783         case FIOASYNC:
  784                 if ((tmp = *(int *)data))
  785                         atomic_set_int(&fp->f_flag, FASYNC);
  786                 else
  787                         atomic_clear_int(&fp->f_flag, FASYNC);
  788                 data = (void *)&tmp;
  789                 break;
  790         }
  791 
  792         error = fo_ioctl(fp, com, data, td->td_ucred, td);
  793 out:
  794         switch (locked) {
  795         case LA_XLOCKED:
  796                 FILEDESC_XUNLOCK(fdp);
  797                 break;
  798 #ifdef CAPABILITIES
  799         case LA_SLOCKED:
  800                 FILEDESC_SUNLOCK(fdp);
  801                 break;
  802 #endif
  803         default:
  804                 FILEDESC_UNLOCK_ASSERT(fdp);
  805                 break;
  806         }
  807         if (fp != NULL)
  808                 fdrop(fp, td);
  809         return (error);
  810 }
  811 
  812 int
  813 poll_no_poll(int events)
  814 {
  815         /*
  816          * Return true for read/write.  If the user asked for something
  817          * special, return POLLNVAL, so that clients have a way of
  818          * determining reliably whether or not the extended
  819          * functionality is present without hard-coding knowledge
  820          * of specific filesystem implementations.
  821          */
  822         if (events & ~POLLSTANDARD)
  823                 return (POLLNVAL);
  824 
  825         return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
  826 }
  827 
  828 int
  829 sys_pselect(struct thread *td, struct pselect_args *uap)
  830 {
  831         struct timespec ts;
  832         struct timeval tv, *tvp;
  833         sigset_t set, *uset;
  834         int error;
  835 
  836         if (uap->ts != NULL) {
  837                 error = copyin(uap->ts, &ts, sizeof(ts));
  838                 if (error != 0)
  839                     return (error);
  840                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
  841                 tvp = &tv;
  842         } else
  843                 tvp = NULL;
  844         if (uap->sm != NULL) {
  845                 error = copyin(uap->sm, &set, sizeof(set));
  846                 if (error != 0)
  847                         return (error);
  848                 uset = &set;
  849         } else
  850                 uset = NULL;
  851         return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  852             uset, NFDBITS));
  853 }
  854 
  855 int
  856 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
  857     struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
  858 {
  859         int error;
  860 
  861         if (uset != NULL) {
  862                 error = kern_sigprocmask(td, SIG_SETMASK, uset,
  863                     &td->td_oldsigmask, 0);
  864                 if (error != 0)
  865                         return (error);
  866                 td->td_pflags |= TDP_OLDMASK;
  867                 /*
  868                  * Make sure that ast() is called on return to
  869                  * usermode and TDP_OLDMASK is cleared, restoring old
  870                  * sigmask.
  871                  */
  872                 thread_lock(td);
  873                 td->td_flags |= TDF_ASTPENDING;
  874                 thread_unlock(td);
  875         }
  876         error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
  877         return (error);
  878 }
  879 
  880 #ifndef _SYS_SYSPROTO_H_
  881 struct select_args {
  882         int     nd;
  883         fd_set  *in, *ou, *ex;
  884         struct  timeval *tv;
  885 };
  886 #endif
  887 int
  888 sys_select(struct thread *td, struct select_args *uap)
  889 {
  890         struct timeval tv, *tvp;
  891         int error;
  892 
  893         if (uap->tv != NULL) {
  894                 error = copyin(uap->tv, &tv, sizeof(tv));
  895                 if (error)
  896                         return (error);
  897                 tvp = &tv;
  898         } else
  899                 tvp = NULL;
  900 
  901         return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
  902             NFDBITS));
  903 }
  904 
  905 /*
  906  * In the unlikely case when user specified n greater then the last
  907  * open file descriptor, check that no bits are set after the last
  908  * valid fd.  We must return EBADF if any is set.
  909  *
  910  * There are applications that rely on the behaviour.
  911  *
  912  * nd is fd_lastfile + 1.
  913  */
  914 static int
  915 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits)
  916 {
  917         char *addr, *oaddr;
  918         int b, i, res;
  919         uint8_t bits;
  920 
  921         if (nd >= ndu || fd_in == NULL)
  922                 return (0);
  923 
  924         oaddr = NULL;
  925         bits = 0; /* silence gcc */
  926         for (i = nd; i < ndu; i++) {
  927                 b = i / NBBY;
  928 #if BYTE_ORDER == LITTLE_ENDIAN
  929                 addr = (char *)fd_in + b;
  930 #else
  931                 addr = (char *)fd_in;
  932                 if (abi_nfdbits == NFDBITS) {
  933                         addr += rounddown(b, sizeof(fd_mask)) +
  934                             sizeof(fd_mask) - 1 - b % sizeof(fd_mask);
  935                 } else {
  936                         addr += rounddown(b, sizeof(uint32_t)) +
  937                             sizeof(uint32_t) - 1 - b % sizeof(uint32_t);
  938                 }
  939 #endif
  940                 if (addr != oaddr) {
  941                         res = fubyte(addr);
  942                         if (res == -1)
  943                                 return (EFAULT);
  944                         oaddr = addr;
  945                         bits = res;
  946                 }
  947                 if ((bits & (1 << (i % NBBY))) != 0)
  948                         return (EBADF);
  949         }
  950         return (0);
  951 }
  952 
  953 int
  954 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
  955     fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
  956 {
  957         struct filedesc *fdp;
  958         /*
  959          * The magic 2048 here is chosen to be just enough for FD_SETSIZE
  960          * infds with the new FD_SETSIZE of 1024, and more than enough for
  961          * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
  962          * of 256.
  963          */
  964         fd_mask s_selbits[howmany(2048, NFDBITS)];
  965         fd_mask *ibits[3], *obits[3], *selbits, *sbp;
  966         struct timeval rtv;
  967         sbintime_t asbt, precision, rsbt;
  968         u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
  969         int error, lf, ndu;
  970 
  971         if (nd < 0)
  972                 return (EINVAL);
  973         fdp = td->td_proc->p_fd;
  974         ndu = nd;
  975         lf = fdp->fd_lastfile;
  976         if (nd > lf + 1)
  977                 nd = lf + 1;
  978 
  979         error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits);
  980         if (error != 0)
  981                 return (error);
  982         error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits);
  983         if (error != 0)
  984                 return (error);
  985         error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits);
  986         if (error != 0)
  987                 return (error);
  988 
  989         /*
  990          * Allocate just enough bits for the non-null fd_sets.  Use the
  991          * preallocated auto buffer if possible.
  992          */
  993         nfdbits = roundup(nd, NFDBITS);
  994         ncpbytes = nfdbits / NBBY;
  995         ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
  996         nbufbytes = 0;
  997         if (fd_in != NULL)
  998                 nbufbytes += 2 * ncpbytes;
  999         if (fd_ou != NULL)
 1000                 nbufbytes += 2 * ncpbytes;
 1001         if (fd_ex != NULL)
 1002                 nbufbytes += 2 * ncpbytes;
 1003         if (nbufbytes <= sizeof s_selbits)
 1004                 selbits = &s_selbits[0];
 1005         else
 1006                 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
 1007 
 1008         /*
 1009          * Assign pointers into the bit buffers and fetch the input bits.
 1010          * Put the output buffers together so that they can be bzeroed
 1011          * together.
 1012          */
 1013         sbp = selbits;
 1014 #define getbits(name, x) \
 1015         do {                                                            \
 1016                 if (name == NULL) {                                     \
 1017                         ibits[x] = NULL;                                \
 1018                         obits[x] = NULL;                                \
 1019                 } else {                                                \
 1020                         ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp;   \
 1021                         obits[x] = sbp;                                 \
 1022                         sbp += ncpbytes / sizeof *sbp;                  \
 1023                         error = copyin(name, ibits[x], ncpubytes);      \
 1024                         if (error != 0)                                 \
 1025                                 goto done;                              \
 1026                         bzero((char *)ibits[x] + ncpubytes,             \
 1027                             ncpbytes - ncpubytes);                      \
 1028                 }                                                       \
 1029         } while (0)
 1030         getbits(fd_in, 0);
 1031         getbits(fd_ou, 1);
 1032         getbits(fd_ex, 2);
 1033 #undef  getbits
 1034 
 1035 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
 1036         /*
 1037          * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
 1038          * we are running under 32-bit emulation. This should be more
 1039          * generic.
 1040          */
 1041 #define swizzle_fdset(bits)                                             \
 1042         if (abi_nfdbits != NFDBITS && bits != NULL) {                   \
 1043                 int i;                                                  \
 1044                 for (i = 0; i < ncpbytes / sizeof *sbp; i++)            \
 1045                         bits[i] = (bits[i] >> 32) | (bits[i] << 32);    \
 1046         }
 1047 #else
 1048 #define swizzle_fdset(bits)
 1049 #endif
 1050 
 1051         /* Make sure the bit order makes it through an ABI transition */
 1052         swizzle_fdset(ibits[0]);
 1053         swizzle_fdset(ibits[1]);
 1054         swizzle_fdset(ibits[2]);
 1055         
 1056         if (nbufbytes != 0)
 1057                 bzero(selbits, nbufbytes / 2);
 1058 
 1059         precision = 0;
 1060         if (tvp != NULL) {
 1061                 rtv = *tvp;
 1062                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
 1063                     rtv.tv_usec >= 1000000) {
 1064                         error = EINVAL;
 1065                         goto done;
 1066                 }
 1067                 if (!timevalisset(&rtv))
 1068                         asbt = 0;
 1069                 else if (rtv.tv_sec <= INT32_MAX) {
 1070                         rsbt = tvtosbt(rtv);
 1071                         precision = rsbt;
 1072                         precision >>= tc_precexp;
 1073                         if (TIMESEL(&asbt, rsbt))
 1074                                 asbt += tc_tick_sbt;
 1075                         if (asbt <= INT64_MAX - rsbt)
 1076                                 asbt += rsbt;
 1077                         else
 1078                                 asbt = -1;
 1079                 } else
 1080                         asbt = -1;
 1081         } else
 1082                 asbt = -1;
 1083         seltdinit(td);
 1084         /* Iterate until the timeout expires or descriptors become ready. */
 1085         for (;;) {
 1086                 error = selscan(td, ibits, obits, nd);
 1087                 if (error || td->td_retval[0] != 0)
 1088                         break;
 1089                 error = seltdwait(td, asbt, precision);
 1090                 if (error)
 1091                         break;
 1092                 error = selrescan(td, ibits, obits);
 1093                 if (error || td->td_retval[0] != 0)
 1094                         break;
 1095         }
 1096         seltdclear(td);
 1097 
 1098 done:
 1099         /* select is not restarted after signals... */
 1100         if (error == ERESTART)
 1101                 error = EINTR;
 1102         if (error == EWOULDBLOCK)
 1103                 error = 0;
 1104 
 1105         /* swizzle bit order back, if necessary */
 1106         swizzle_fdset(obits[0]);
 1107         swizzle_fdset(obits[1]);
 1108         swizzle_fdset(obits[2]);
 1109 #undef swizzle_fdset
 1110 
 1111 #define putbits(name, x) \
 1112         if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
 1113                 error = error2;
 1114         if (error == 0) {
 1115                 int error2;
 1116 
 1117                 putbits(fd_in, 0);
 1118                 putbits(fd_ou, 1);
 1119                 putbits(fd_ex, 2);
 1120 #undef putbits
 1121         }
 1122         if (selbits != &s_selbits[0])
 1123                 free(selbits, M_SELECT);
 1124 
 1125         return (error);
 1126 }
 1127 /* 
 1128  * Convert a select bit set to poll flags.
 1129  *
 1130  * The backend always returns POLLHUP/POLLERR if appropriate and we
 1131  * return this as a set bit in any set.
 1132  */
 1133 static int select_flags[3] = {
 1134     POLLRDNORM | POLLHUP | POLLERR,
 1135     POLLWRNORM | POLLHUP | POLLERR,
 1136     POLLRDBAND | POLLERR
 1137 };
 1138 
 1139 /*
 1140  * Compute the fo_poll flags required for a fd given by the index and
 1141  * bit position in the fd_mask array.
 1142  */
 1143 static __inline int
 1144 selflags(fd_mask **ibits, int idx, fd_mask bit)
 1145 {
 1146         int flags;
 1147         int msk;
 1148 
 1149         flags = 0;
 1150         for (msk = 0; msk < 3; msk++) {
 1151                 if (ibits[msk] == NULL)
 1152                         continue;
 1153                 if ((ibits[msk][idx] & bit) == 0)
 1154                         continue;
 1155                 flags |= select_flags[msk];
 1156         }
 1157         return (flags);
 1158 }
 1159 
 1160 /*
 1161  * Set the appropriate output bits given a mask of fired events and the
 1162  * input bits originally requested.
 1163  */
 1164 static __inline int
 1165 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
 1166 {
 1167         int msk;
 1168         int n;
 1169 
 1170         n = 0;
 1171         for (msk = 0; msk < 3; msk++) {
 1172                 if ((events & select_flags[msk]) == 0)
 1173                         continue;
 1174                 if (ibits[msk] == NULL)
 1175                         continue;
 1176                 if ((ibits[msk][idx] & bit) == 0)
 1177                         continue;
 1178                 /*
 1179                  * XXX Check for a duplicate set.  This can occur because a
 1180                  * socket calls selrecord() twice for each poll() call
 1181                  * resulting in two selfds per real fd.  selrescan() will
 1182                  * call selsetbits twice as a result.
 1183                  */
 1184                 if ((obits[msk][idx] & bit) != 0)
 1185                         continue;
 1186                 obits[msk][idx] |= bit;
 1187                 n++;
 1188         }
 1189 
 1190         return (n);
 1191 }
 1192 
 1193 static __inline int
 1194 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp)
 1195 {
 1196         cap_rights_t rights;
 1197 
 1198         cap_rights_init(&rights, CAP_EVENT);
 1199 
 1200         return (fget_unlocked(fdp, fd, &rights, 0, fpp, NULL));
 1201 }
 1202 
 1203 /*
 1204  * Traverse the list of fds attached to this thread's seltd and check for
 1205  * completion.
 1206  */
 1207 static int
 1208 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
 1209 {
 1210         struct filedesc *fdp;
 1211         struct selinfo *si;
 1212         struct seltd *stp;
 1213         struct selfd *sfp;
 1214         struct selfd *sfn;
 1215         struct file *fp;
 1216         fd_mask bit;
 1217         int fd, ev, n, idx;
 1218         int error;
 1219 
 1220         fdp = td->td_proc->p_fd;
 1221         stp = td->td_sel;
 1222         n = 0;
 1223         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1224                 fd = (int)(uintptr_t)sfp->sf_cookie;
 1225                 si = sfp->sf_si;
 1226                 selfdfree(stp, sfp);
 1227                 /* If the selinfo wasn't cleared the event didn't fire. */
 1228                 if (si != NULL)
 1229                         continue;
 1230                 error = getselfd_cap(fdp, fd, &fp);
 1231                 if (error)
 1232                         return (error);
 1233                 idx = fd / NFDBITS;
 1234                 bit = (fd_mask)1 << (fd % NFDBITS);
 1235                 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
 1236                 fdrop(fp, td);
 1237                 if (ev != 0)
 1238                         n += selsetbits(ibits, obits, idx, bit, ev);
 1239         }
 1240         stp->st_flags = 0;
 1241         td->td_retval[0] = n;
 1242         return (0);
 1243 }
 1244 
 1245 /*
 1246  * Perform the initial filedescriptor scan and register ourselves with
 1247  * each selinfo.
 1248  */
 1249 static int
 1250 selscan(td, ibits, obits, nfd)
 1251         struct thread *td;
 1252         fd_mask **ibits, **obits;
 1253         int nfd;
 1254 {
 1255         struct filedesc *fdp;
 1256         struct file *fp;
 1257         fd_mask bit;
 1258         int ev, flags, end, fd;
 1259         int n, idx;
 1260         int error;
 1261 
 1262         fdp = td->td_proc->p_fd;
 1263         n = 0;
 1264         for (idx = 0, fd = 0; fd < nfd; idx++) {
 1265                 end = imin(fd + NFDBITS, nfd);
 1266                 for (bit = 1; fd < end; bit <<= 1, fd++) {
 1267                         /* Compute the list of events we're interested in. */
 1268                         flags = selflags(ibits, idx, bit);
 1269                         if (flags == 0)
 1270                                 continue;
 1271                         error = getselfd_cap(fdp, fd, &fp);
 1272                         if (error)
 1273                                 return (error);
 1274                         selfdalloc(td, (void *)(uintptr_t)fd);
 1275                         ev = fo_poll(fp, flags, td->td_ucred, td);
 1276                         fdrop(fp, td);
 1277                         if (ev != 0)
 1278                                 n += selsetbits(ibits, obits, idx, bit, ev);
 1279                 }
 1280         }
 1281 
 1282         td->td_retval[0] = n;
 1283         return (0);
 1284 }
 1285 
 1286 #ifndef _SYS_SYSPROTO_H_
 1287 struct poll_args {
 1288         struct pollfd *fds;
 1289         u_int   nfds;
 1290         int     timeout;
 1291 };
 1292 #endif
 1293 int
 1294 sys_poll(td, uap)
 1295         struct thread *td;
 1296         struct poll_args *uap;
 1297 {
 1298         struct pollfd *bits;
 1299         struct pollfd smallbits[32];
 1300         sbintime_t asbt, precision, rsbt;
 1301         u_int nfds;
 1302         int error;
 1303         size_t ni;
 1304 
 1305         nfds = uap->nfds;
 1306         if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 
 1307                 return (EINVAL);
 1308         ni = nfds * sizeof(struct pollfd);
 1309         if (ni > sizeof(smallbits))
 1310                 bits = malloc(ni, M_TEMP, M_WAITOK);
 1311         else
 1312                 bits = smallbits;
 1313         error = copyin(uap->fds, bits, ni);
 1314         if (error)
 1315                 goto done;
 1316         precision = 0;
 1317         if (uap->timeout != INFTIM) {
 1318                 if (uap->timeout < 0) {
 1319                         error = EINVAL;
 1320                         goto done;
 1321                 }
 1322                 if (uap->timeout == 0)
 1323                         asbt = 0;
 1324                 else {
 1325                         rsbt = SBT_1MS * uap->timeout;
 1326                         precision = rsbt;
 1327                         precision >>= tc_precexp;
 1328                         if (TIMESEL(&asbt, rsbt))
 1329                                 asbt += tc_tick_sbt;
 1330                         asbt += rsbt;
 1331                 }
 1332         } else
 1333                 asbt = -1;
 1334         seltdinit(td);
 1335         /* Iterate until the timeout expires or descriptors become ready. */
 1336         for (;;) {
 1337                 error = pollscan(td, bits, nfds);
 1338                 if (error || td->td_retval[0] != 0)
 1339                         break;
 1340                 error = seltdwait(td, asbt, precision);
 1341                 if (error)
 1342                         break;
 1343                 error = pollrescan(td);
 1344                 if (error || td->td_retval[0] != 0)
 1345                         break;
 1346         }
 1347         seltdclear(td);
 1348 
 1349 done:
 1350         /* poll is not restarted after signals... */
 1351         if (error == ERESTART)
 1352                 error = EINTR;
 1353         if (error == EWOULDBLOCK)
 1354                 error = 0;
 1355         if (error == 0) {
 1356                 error = pollout(td, bits, uap->fds, nfds);
 1357                 if (error)
 1358                         goto out;
 1359         }
 1360 out:
 1361         if (ni > sizeof(smallbits))
 1362                 free(bits, M_TEMP);
 1363         return (error);
 1364 }
 1365 
 1366 static int
 1367 pollrescan(struct thread *td)
 1368 {
 1369         struct seltd *stp;
 1370         struct selfd *sfp;
 1371         struct selfd *sfn;
 1372         struct selinfo *si;
 1373         struct filedesc *fdp;
 1374         struct file *fp;
 1375         struct pollfd *fd;
 1376 #ifdef CAPABILITIES
 1377         cap_rights_t rights;
 1378 #endif
 1379         int n;
 1380 
 1381         n = 0;
 1382         fdp = td->td_proc->p_fd;
 1383         stp = td->td_sel;
 1384         FILEDESC_SLOCK(fdp);
 1385         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
 1386                 fd = (struct pollfd *)sfp->sf_cookie;
 1387                 si = sfp->sf_si;
 1388                 selfdfree(stp, sfp);
 1389                 /* If the selinfo wasn't cleared the event didn't fire. */
 1390                 if (si != NULL)
 1391                         continue;
 1392                 fp = fdp->fd_ofiles[fd->fd].fde_file;
 1393 #ifdef CAPABILITIES
 1394                 if (fp == NULL ||
 1395                     cap_check(cap_rights(fdp, fd->fd),
 1396                     cap_rights_init(&rights, CAP_EVENT)) != 0)
 1397 #else
 1398                 if (fp == NULL)
 1399 #endif
 1400                 {
 1401                         fd->revents = POLLNVAL;
 1402                         n++;
 1403                         continue;
 1404                 }
 1405 
 1406                 /*
 1407                  * Note: backend also returns POLLHUP and
 1408                  * POLLERR if appropriate.
 1409                  */
 1410                 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
 1411                 if (fd->revents != 0)
 1412                         n++;
 1413         }
 1414         FILEDESC_SUNLOCK(fdp);
 1415         stp->st_flags = 0;
 1416         td->td_retval[0] = n;
 1417         return (0);
 1418 }
 1419 
 1420 
 1421 static int
 1422 pollout(td, fds, ufds, nfd)
 1423         struct thread *td;
 1424         struct pollfd *fds;
 1425         struct pollfd *ufds;
 1426         u_int nfd;
 1427 {
 1428         int error = 0;
 1429         u_int i = 0;
 1430         u_int n = 0;
 1431 
 1432         for (i = 0; i < nfd; i++) {
 1433                 error = copyout(&fds->revents, &ufds->revents,
 1434                     sizeof(ufds->revents));
 1435                 if (error)
 1436                         return (error);
 1437                 if (fds->revents != 0)
 1438                         n++;
 1439                 fds++;
 1440                 ufds++;
 1441         }
 1442         td->td_retval[0] = n;
 1443         return (0);
 1444 }
 1445 
 1446 static int
 1447 pollscan(td, fds, nfd)
 1448         struct thread *td;
 1449         struct pollfd *fds;
 1450         u_int nfd;
 1451 {
 1452         struct filedesc *fdp = td->td_proc->p_fd;
 1453         struct file *fp;
 1454 #ifdef CAPABILITIES
 1455         cap_rights_t rights;
 1456 #endif
 1457         int i, n = 0;
 1458 
 1459         FILEDESC_SLOCK(fdp);
 1460         for (i = 0; i < nfd; i++, fds++) {
 1461                 if (fds->fd > fdp->fd_lastfile) {
 1462                         fds->revents = POLLNVAL;
 1463                         n++;
 1464                 } else if (fds->fd < 0) {
 1465                         fds->revents = 0;
 1466                 } else {
 1467                         fp = fdp->fd_ofiles[fds->fd].fde_file;
 1468 #ifdef CAPABILITIES
 1469                         if (fp == NULL ||
 1470                             cap_check(cap_rights(fdp, fds->fd),
 1471                             cap_rights_init(&rights, CAP_EVENT)) != 0)
 1472 #else
 1473                         if (fp == NULL)
 1474 #endif
 1475                         {
 1476                                 fds->revents = POLLNVAL;
 1477                                 n++;
 1478                         } else {
 1479                                 /*
 1480                                  * Note: backend also returns POLLHUP and
 1481                                  * POLLERR if appropriate.
 1482                                  */
 1483                                 selfdalloc(td, fds);
 1484                                 fds->revents = fo_poll(fp, fds->events,
 1485                                     td->td_ucred, td);
 1486                                 /*
 1487                                  * POSIX requires POLLOUT to be never
 1488                                  * set simultaneously with POLLHUP.
 1489                                  */
 1490                                 if ((fds->revents & POLLHUP) != 0)
 1491                                         fds->revents &= ~POLLOUT;
 1492 
 1493                                 if (fds->revents != 0)
 1494                                         n++;
 1495                         }
 1496                 }
 1497         }
 1498         FILEDESC_SUNLOCK(fdp);
 1499         td->td_retval[0] = n;
 1500         return (0);
 1501 }
 1502 
 1503 /*
 1504  * OpenBSD poll system call.
 1505  *
 1506  * XXX this isn't quite a true representation..  OpenBSD uses select ops.
 1507  */
 1508 #ifndef _SYS_SYSPROTO_H_
 1509 struct openbsd_poll_args {
 1510         struct pollfd *fds;
 1511         u_int   nfds;
 1512         int     timeout;
 1513 };
 1514 #endif
 1515 int
 1516 sys_openbsd_poll(td, uap)
 1517         register struct thread *td;
 1518         register struct openbsd_poll_args *uap;
 1519 {
 1520         return (sys_poll(td, (struct poll_args *)uap));
 1521 }
 1522 
 1523 /*
 1524  * XXX This was created specifically to support netncp and netsmb.  This
 1525  * allows the caller to specify a socket to wait for events on.  It returns
 1526  * 0 if any events matched and an error otherwise.  There is no way to
 1527  * determine which events fired.
 1528  */
 1529 int
 1530 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
 1531 {
 1532         struct timeval rtv;
 1533         sbintime_t asbt, precision, rsbt;
 1534         int error;
 1535 
 1536         precision = 0;  /* stupid gcc! */
 1537         if (tvp != NULL) {
 1538                 rtv = *tvp;
 1539                 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 || 
 1540                     rtv.tv_usec >= 1000000)
 1541                         return (EINVAL);
 1542                 if (!timevalisset(&rtv))
 1543                         asbt = 0;
 1544                 else if (rtv.tv_sec <= INT32_MAX) {
 1545                         rsbt = tvtosbt(rtv);
 1546                         precision = rsbt;
 1547                         precision >>= tc_precexp;
 1548                         if (TIMESEL(&asbt, rsbt))
 1549                                 asbt += tc_tick_sbt;
 1550                         if (asbt <= INT64_MAX - rsbt)
 1551                                 asbt += rsbt;
 1552                         else
 1553                                 asbt = -1;
 1554                 } else
 1555                         asbt = -1;
 1556         } else
 1557                 asbt = -1;
 1558         seltdinit(td);
 1559         /*
 1560          * Iterate until the timeout expires or the socket becomes ready.
 1561          */
 1562         for (;;) {
 1563                 selfdalloc(td, NULL);
 1564                 error = sopoll(so, events, NULL, td);
 1565                 /* error here is actually the ready events. */
 1566                 if (error)
 1567                         return (0);
 1568                 error = seltdwait(td, asbt, precision);
 1569                 if (error)
 1570                         break;
 1571         }
 1572         seltdclear(td);
 1573         /* XXX Duplicates ncp/smb behavior. */
 1574         if (error == ERESTART)
 1575                 error = 0;
 1576         return (error);
 1577 }
 1578 
 1579 /*
 1580  * Preallocate two selfds associated with 'cookie'.  Some fo_poll routines
 1581  * have two select sets, one for read and another for write.
 1582  */
 1583 static void
 1584 selfdalloc(struct thread *td, void *cookie)
 1585 {
 1586         struct seltd *stp;
 1587 
 1588         stp = td->td_sel;
 1589         if (stp->st_free1 == NULL)
 1590                 stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1591         stp->st_free1->sf_td = stp;
 1592         stp->st_free1->sf_cookie = cookie;
 1593         if (stp->st_free2 == NULL)
 1594                 stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
 1595         stp->st_free2->sf_td = stp;
 1596         stp->st_free2->sf_cookie = cookie;
 1597 }
 1598 
 1599 static void
 1600 selfdfree(struct seltd *stp, struct selfd *sfp)
 1601 {
 1602         STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
 1603         mtx_lock(sfp->sf_mtx);
 1604         if (sfp->sf_si)
 1605                 TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
 1606         mtx_unlock(sfp->sf_mtx);
 1607         uma_zfree(selfd_zone, sfp);
 1608 }
 1609 
 1610 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */
 1611 void
 1612 seldrain(sip)
 1613         struct selinfo *sip;
 1614 {
 1615 
 1616         /*
 1617          * This feature is already provided by doselwakeup(), thus it is
 1618          * enough to go for it.
 1619          * Eventually, the context, should take care to avoid races
 1620          * between thread calling select()/poll() and file descriptor
 1621          * detaching, but, again, the races are just the same as
 1622          * selwakeup().
 1623          */
 1624         doselwakeup(sip, -1);
 1625 }
 1626 
 1627 /*
 1628  * Record a select request.
 1629  */
 1630 void
 1631 selrecord(selector, sip)
 1632         struct thread *selector;
 1633         struct selinfo *sip;
 1634 {
 1635         struct selfd *sfp;
 1636         struct seltd *stp;
 1637         struct mtx *mtxp;
 1638 
 1639         stp = selector->td_sel;
 1640         /*
 1641          * Don't record when doing a rescan.
 1642          */
 1643         if (stp->st_flags & SELTD_RESCAN)
 1644                 return;
 1645         /*
 1646          * Grab one of the preallocated descriptors.
 1647          */
 1648         sfp = NULL;
 1649         if ((sfp = stp->st_free1) != NULL)
 1650                 stp->st_free1 = NULL;
 1651         else if ((sfp = stp->st_free2) != NULL)
 1652                 stp->st_free2 = NULL;
 1653         else
 1654                 panic("selrecord: No free selfd on selq");
 1655         mtxp = sip->si_mtx;
 1656         if (mtxp == NULL)
 1657                 mtxp = mtx_pool_find(mtxpool_select, sip);
 1658         /*
 1659          * Initialize the sfp and queue it in the thread.
 1660          */
 1661         sfp->sf_si = sip;
 1662         sfp->sf_mtx = mtxp;
 1663         STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
 1664         /*
 1665          * Now that we've locked the sip, check for initialization.
 1666          */
 1667         mtx_lock(mtxp);
 1668         if (sip->si_mtx == NULL) {
 1669                 sip->si_mtx = mtxp;
 1670                 TAILQ_INIT(&sip->si_tdlist);
 1671         }
 1672         /*
 1673          * Add this thread to the list of selfds listening on this selinfo.
 1674          */
 1675         TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
 1676         mtx_unlock(sip->si_mtx);
 1677 }
 1678 
 1679 /* Wake up a selecting thread. */
 1680 void
 1681 selwakeup(sip)
 1682         struct selinfo *sip;
 1683 {
 1684         doselwakeup(sip, -1);
 1685 }
 1686 
 1687 /* Wake up a selecting thread, and set its priority. */
 1688 void
 1689 selwakeuppri(sip, pri)
 1690         struct selinfo *sip;
 1691         int pri;
 1692 {
 1693         doselwakeup(sip, pri);
 1694 }
 1695 
 1696 /*
 1697  * Do a wakeup when a selectable event occurs.
 1698  */
 1699 static void
 1700 doselwakeup(sip, pri)
 1701         struct selinfo *sip;
 1702         int pri;
 1703 {
 1704         struct selfd *sfp;
 1705         struct selfd *sfn;
 1706         struct seltd *stp;
 1707 
 1708         /* If it's not initialized there can't be any waiters. */
 1709         if (sip->si_mtx == NULL)
 1710                 return;
 1711         /*
 1712          * Locking the selinfo locks all selfds associated with it.
 1713          */
 1714         mtx_lock(sip->si_mtx);
 1715         TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
 1716                 /*
 1717                  * Once we remove this sfp from the list and clear the
 1718                  * sf_si seltdclear will know to ignore this si.
 1719                  */
 1720                 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
 1721                 sfp->sf_si = NULL;
 1722                 stp = sfp->sf_td;
 1723                 mtx_lock(&stp->st_mtx);
 1724                 stp->st_flags |= SELTD_PENDING;
 1725                 cv_broadcastpri(&stp->st_wait, pri);
 1726                 mtx_unlock(&stp->st_mtx);
 1727         }
 1728         mtx_unlock(sip->si_mtx);
 1729 }
 1730 
 1731 static void
 1732 seltdinit(struct thread *td)
 1733 {
 1734         struct seltd *stp;
 1735 
 1736         if ((stp = td->td_sel) != NULL)
 1737                 goto out;
 1738         td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
 1739         mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
 1740         cv_init(&stp->st_wait, "select");
 1741 out:
 1742         stp->st_flags = 0;
 1743         STAILQ_INIT(&stp->st_selq);
 1744 }
 1745 
 1746 static int
 1747 seltdwait(struct thread *td, sbintime_t sbt, sbintime_t precision)
 1748 {
 1749         struct seltd *stp;
 1750         int error;
 1751 
 1752         stp = td->td_sel;
 1753         /*
 1754          * An event of interest may occur while we do not hold the seltd
 1755          * locked so check the pending flag before we sleep.
 1756          */
 1757         mtx_lock(&stp->st_mtx);
 1758         /*
 1759          * Any further calls to selrecord will be a rescan.
 1760          */
 1761         stp->st_flags |= SELTD_RESCAN;
 1762         if (stp->st_flags & SELTD_PENDING) {
 1763                 mtx_unlock(&stp->st_mtx);
 1764                 return (0);
 1765         }
 1766         if (sbt == 0)
 1767                 error = EWOULDBLOCK;
 1768         else if (sbt != -1)
 1769                 error = cv_timedwait_sig_sbt(&stp->st_wait, &stp->st_mtx,
 1770                     sbt, precision, C_ABSOLUTE);
 1771         else
 1772                 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
 1773         mtx_unlock(&stp->st_mtx);
 1774 
 1775         return (error);
 1776 }
 1777 
 1778 void
 1779 seltdfini(struct thread *td)
 1780 {
 1781         struct seltd *stp;
 1782 
 1783         stp = td->td_sel;
 1784         if (stp == NULL)
 1785                 return;
 1786         if (stp->st_free1)
 1787                 uma_zfree(selfd_zone, stp->st_free1);
 1788         if (stp->st_free2)
 1789                 uma_zfree(selfd_zone, stp->st_free2);
 1790         td->td_sel = NULL;
 1791         free(stp, M_SELECT);
 1792 }
 1793 
 1794 /*
 1795  * Remove the references to the thread from all of the objects we were
 1796  * polling.
 1797  */
 1798 static void
 1799 seltdclear(struct thread *td)
 1800 {
 1801         struct seltd *stp;
 1802         struct selfd *sfp;
 1803         struct selfd *sfn;
 1804 
 1805         stp = td->td_sel;
 1806         STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
 1807                 selfdfree(stp, sfp);
 1808         stp->st_flags = 0;
 1809 }
 1810 
 1811 static void selectinit(void *);
 1812 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
 1813 static void
 1814 selectinit(void *dummy __unused)
 1815 {
 1816 
 1817         selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
 1818             NULL, NULL, UMA_ALIGN_PTR, 0);
 1819         mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
 1820 }

Cache object: 678452cf74b0c4c53d742df42bfb2b6a


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