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 (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26 
  27 /*
  28  * Redirection STREAMS module.
  29  *
  30  * This module is intended for use in conjunction with instantiations of the
  31  * redirection driver.  Its purpose in life is to detect when the stream that
  32  * it's pushed on is closed, thereupon calling back into the redirection
  33  * driver so that the driver can cancel redirection to the stream.
  34  * It passes all messages on unchanged, in both directions.
  35  */
  36 
  37 #include <sys/types.h>
  38 #include <sys/param.h>
  39 #include <sys/errno.h>
  40 #include <sys/stream.h>
  41 #include <sys/stropts.h>
  42 #include <sys/debug.h>
  43 #include <sys/strredir.h>
  44 #include <sys/strsubr.h>
  45 #include <sys/strsun.h>
  46 #include <sys/conf.h>
  47 #include <sys/ddi.h>
  48 #include <sys/sunddi.h>
  49 #include <sys/modctl.h>
  50 
  51 /*
  52  * Forward declarations for private routines.
  53  */
  54 static int      wcmopen(queue_t *, dev_t *, int, int, cred_t *);
  55 static int      wcmclose(queue_t *, int, cred_t *);
  56 static int      wcmrput(queue_t *, mblk_t *);
  57 
  58 static struct module_info       wcminfo = {
  59         STRREDIR_MODID,
  60         STRREDIR_MOD,
  61         0,
  62         INFPSZ,
  63         5120,
  64         1024
  65 };
  66 
  67 static struct qinit     wcmrinit = {
  68         wcmrput,                /* put */
  69         NULL,                   /* service */
  70         wcmopen,                /* open */
  71         wcmclose,               /* close */
  72         NULL,                   /* qadmin */
  73         &wcminfo,
  74         NULL                    /* mstat */
  75 };
  76 
  77 static struct qinit     wcmwinit = {
  78         (int (*)())putnext,     /* put */
  79         NULL,                   /* service */
  80         wcmopen,                /* open */
  81         wcmclose,               /* close */
  82         NULL,                   /* qadmin */
  83         &wcminfo,
  84         NULL                    /* mstat */
  85 };
  86 
  87 static struct streamtab redirminfo = {
  88         &wcmrinit,
  89         &wcmwinit,
  90         NULL,
  91         NULL
  92 };
  93 
  94 static struct fmodsw fsw = {
  95         "redirmod",
  96         &redirminfo,
  97         D_MP
  98 };
  99 
 100 static struct modlstrmod modlstrmod = {
 101         &mod_strmodops,
 102         "redirection module",
 103         &fsw
 104 };
 105 
 106 static struct modlinkage modlinkage = {
 107         MODREV_1, { &modlstrmod, NULL }
 108 };
 109 
 110 int
 111 _init()
 112 {
 113         return (mod_install(&modlinkage));
 114 }
 115 
 116 int
 117 _fini()
 118 {
 119         return (EBUSY);
 120 }
 121 
 122 int
 123 _info(struct modinfo *modinfop)
 124 {
 125         return (mod_info(&modlinkage, modinfop));
 126 }
 127 
 128 /* ARGSUSED */
 129 static int
 130 wcmopen(queue_t *q, dev_t *dev, int flag, int sflag, cred_t *cred)
 131 {
 132         if (sflag != MODOPEN)
 133                 return (EINVAL);
 134         qprocson(q);
 135         return (0);
 136 }
 137 
 138 /* ARGSUSED */
 139 static int
 140 wcmclose(queue_t *q, int flag, cred_t *cred)
 141 {
 142         qprocsoff(q);
 143         srpop(q->q_stream->sd_vnode, B_TRUE);
 144         return (0);
 145 }
 146 
 147 /*
 148  * Upstream messages are passed unchanged.
 149  * If a hangup occurs the target is no longer usable, so deprecate it.
 150  */
 151 static int
 152 wcmrput(queue_t *q, mblk_t *mp)
 153 {
 154         if (DB_TYPE(mp) == M_HANGUP)
 155                 /* Don't block waiting for outstanding operations to complete */
 156                 srpop(q->q_stream->sd_vnode, B_FALSE);
 157         putnext(q, mp);
 158         return (0);
 159 }