usr/src/uts/common/ktli/t_kspoll.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 1997 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 /*
  31  * University Copyright- Copyright (c) 1982, 1986, 1988
  32  * The Regents of the University of California
  33  * All Rights Reserved
  34  *
  35  * University Acknowledgment- Portions of this document are derived from
  36  * software developed by the University of California, Berkeley, and its
  37  * contributors.
  38  */
  39
  40 #pragma ident   "%Z%%M% %I%     %E% SMI"
  41
  42 /*
  43  * This function waits for timo clock ticks for something to arrive on
  44  * the specified stream. If more than one client is hanging off of a
  45  * single endpoint, and at least one has specified a non-zero timeout,
  46  * then all will be woken.
  47  *
  48  * Returns:
  49  *      0 on success or positive error code. On
  50  *      success, "events" is set to
  51  *       0      on timeout or no events(timout = 0),
  52  *       1      if desired event has occurred
  53  *
  54  * Most of the code is from strwaitq().
  55  */
  56
  57 #include <sys/param.h>
  58 #include <sys/types.h>
  59 #include <sys/proc.h>
  60 #include <sys/file.h>
  61 #include <sys/user.h>
  62 #include <sys/vnode.h>
  63 #include <sys/errno.h>
  64 #include <sys/stream.h>
  65 #include <sys/ioctl.h>
  66 #include <sys/stropts.h>
  67 #include <sys/strsubr.h>
  68 #include <sys/tihdr.h>
  69 #include <sys/timod.h>
  70 #include <sys/tiuser.h>
  71 #include <sys/t_kuser.h>
  72 #include <sys/signal.h>
  73 #include <sys/siginfo.h>
  74 #include <sys/time.h>
  75 #include <sys/debug.h>
  76
  77 /*
  78  * Poll for an input event.
  79  *
  80  * timo is measured in ticks
  81  */
  82 int
  83 t_kspoll(TIUSER *tiptr, int timo, int waitflg, int *events)
  84 {
  85         file_t          *fp;
  86         vnode_t         *vp;
  87         klwp_t          *lwp = ttolwp(curthread);
  88         clock_t         timout; /* milliseconds */
  89         int             error;
  90         u_char          pri;
  91         int             pflag;
  92         rval_t          rval;
  93
  94         fp = tiptr->fp;
  95         vp = fp->f_vnode;
  96
  97         if (events == NULL || ((waitflg & READWAIT) == 0))
  98                 return (EINVAL);
  99
 100         /* Convert from ticks to milliseconds */
 101         if (timo < 0)
 102                 timout = -1;
 103         else
 104                 timout = TICK_TO_MSEC(timo);
 105
 106         /*
 107          * Indicate that the lwp is not to be stopped while doing
 108          * this network traffic.  This is to avoid deadlock while
 109          * debugging a process via /proc.
 110          */
 111         if (lwp != NULL)
 112                 lwp->lwp_nostop++;
 113
 114         if (waitflg & NOINTR)
 115                 pflag = MSG_ANY | MSG_HOLDSIG;
 116         else
 117                 pflag = MSG_ANY;
 118         pri = 0;
 119         error = kstrgetmsg(vp, NULL, NULL, &pri, &pflag, timout, &rval);
 120
 121         if (lwp != NULL)
 122                 lwp->lwp_nostop--;
 123
 124         /* Set the return *events. */
 125         if (error != 0) {
 126                 if (error == ETIME) {
 127                         *events = 0;
 128                         error = 0;
 129                 }
 130                 return (error);
 131         }
 132         *events = 1;
 133         return (0);
 134 }