xref: /illumos-gate/usr/src/uts/common/io/connld.c (revision ddb365bfc9e868ad24ccdcb0dc91af18b10df082)
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 2004 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  * This module establishes a unique connection on
32  * a STREAMS-based pipe.
33  */
34 #include <sys/types.h>
35 #include <sys/sysmacros.h>
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/errno.h>
39 #include <sys/signal.h>
40 #include <sys/user.h>
41 #include <sys/fstyp.h>
42 #include <sys/stropts.h>
43 #include <sys/stream.h>
44 #include <sys/strsubr.h>
45 #include <sys/vnode.h>
46 #include <sys/file.h>
47 #include <sys/fs/fifonode.h>
48 #include <sys/debug.h>
49 #include <sys/ddi.h>
50 
51 /*
52  * This is the loadable module wrapper.
53  */
54 #include <sys/conf.h>
55 #include <sys/modctl.h>
56 
57 extern struct streamtab conninfo;
58 
59 static struct fmodsw fsw = {
60 	"connld",
61 	&conninfo,
62 	D_NEW | D_MP
63 };
64 
65 /*
66  * Module linkage information for the kernel.
67  */
68 
69 static struct modlstrmod modlstrmod = {
70 	&mod_strmodops, "Streams-based pipes", &fsw
71 };
72 
73 static struct modlinkage modlinkage = {
74 	MODREV_1, (void *)&modlstrmod, NULL
75 };
76 
77 int
78 _init()
79 {
80 	return (mod_install(&modlinkage));
81 }
82 
83 int
84 _fini()
85 {
86 	return (mod_remove(&modlinkage));
87 }
88 
89 int
90 _info(struct modinfo *modinfop)
91 {
92 	return (mod_info(&modlinkage, modinfop));
93 }
94 
95 /*
96  * Define local and external routines.
97  */
98 int connopen(queue_t *, dev_t *, int, int, cred_t *);
99 int connclose(queue_t *, int, cred_t *);
100 int connput(queue_t *, mblk_t *);
101 
102 /*
103  * Define STREAMS header information.
104  */
105 static struct module_info conn_info = {
106 	1003,
107 	"connld",
108 	0,
109 	INFPSZ,
110 	STRHIGH,
111 	STRLOW
112 };
113 static struct qinit connrinit = {
114 	connput,
115 	NULL,
116 	connopen,
117 	connclose,
118 	NULL,
119 	&conn_info,
120 	NULL
121 };
122 static struct qinit connwinit = {
123 	connput,
124 	NULL,
125 	NULL,
126 	NULL,
127 	NULL,
128 	&conn_info,
129 	NULL
130 };
131 struct streamtab conninfo = {
132 	&connrinit,
133 	&connwinit
134 };
135 
136 /*
137  * For each invocation of connopen(), create a new pipe. One end of the pipe
138  * is sent to the process on the other end of this STREAM. The vnode for
139  * the other end is returned to the open() system call as the vnode for
140  * the opened object.
141  *
142  * On the first invocation of connopen(), a flag is set and the routine
143  * returns 0, since the first open corresponds to the pushing of the module.
144  */
145 /*ARGSUSED*/
146 int
147 connopen(queue_t *rqp, dev_t *devp, int flag, int sflag, cred_t *crp)
148 {
149 	int error = 0;
150 	vnode_t *streamvp;
151 	fifonode_t *streamfnp;
152 
153 	if ((streamvp = strq2vp(rqp)) == NULL) {
154 		return (EINVAL);
155 	}
156 
157 	/*
158 	 * CONNLD is only allowed to be pushed onto a "pipe" that has both
159 	 * of its ends open.
160 	 */
161 	if (streamvp->v_type != VFIFO) {
162 		error = EINVAL;
163 		goto out;
164 	}
165 
166 	streamfnp = VTOF(streamvp);
167 
168 	if (!(streamfnp->fn_flag & ISPIPE) ||
169 	    streamfnp->fn_dest->fn_open == 0) {
170 		error = EPIPE;
171 		goto out;
172 	}
173 
174 	/*
175 	 * If this is the first time CONNLD was opened while on this stream,
176 	 * it is being pushed. Therefore, set a flag and return 0.
177 	 */
178 	if (rqp->q_ptr == 0) {
179 		if (streamfnp->fn_flag & FIFOCONNLD) {
180 			error = ENXIO;
181 			goto out;
182 		}
183 		rqp->q_ptr = (caddr_t)1;
184 		streamfnp->fn_flag |= FIFOCONNLD;
185 		qprocson(rqp);
186 	}
187 out:
188 	VN_RELE(streamvp);
189 	return (error);
190 }
191 
192 /*ARGSUSED*/
193 int
194 connclose(queue_t *q, int cflag, cred_t *crp)
195 {
196 	vnode_t *streamvp;
197 	fifonode_t *streamfnp;
198 
199 	qprocsoff(q);
200 	streamvp = strq2vp(q);
201 
202 	ASSERT(streamvp != NULL);
203 	ASSERT(streamvp->v_type == VFIFO);
204 
205 	streamfnp = VTOF(streamvp);
206 	streamfnp->fn_flag &= ~FIFOCONNLD;
207 	VN_RELE(streamvp);
208 	return (0);
209 }
210 
211 /*
212  * Use same put procedure for write and read queues.
213  */
214 int
215 connput(queue_t *q, mblk_t *bp)
216 {
217 	putnext(q, bp);
218 	return (0);
219 }
220