xref: /onnv-gate/usr/src/lib/libslp/clib/slp_ipc.c (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright (c) 1999-2001 by Sun Microsystems, Inc.
24*0Sstevel@tonic-gate  * All rights reserved.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
28*0Sstevel@tonic-gate 
29*0Sstevel@tonic-gate #include <stdio.h>
30*0Sstevel@tonic-gate #include <stdlib.h>
31*0Sstevel@tonic-gate #include <sys/types.h>
32*0Sstevel@tonic-gate #include <sys/socket.h>
33*0Sstevel@tonic-gate #include <string.h>
34*0Sstevel@tonic-gate #include <errno.h>
35*0Sstevel@tonic-gate #include <arpa/inet.h>
36*0Sstevel@tonic-gate #include <unistd.h>
37*0Sstevel@tonic-gate #include <syslog.h>
38*0Sstevel@tonic-gate #include <thread.h>
39*0Sstevel@tonic-gate #include <synch.h>
40*0Sstevel@tonic-gate #include <netinet/in.h>
41*0Sstevel@tonic-gate #include <signal.h>
42*0Sstevel@tonic-gate #include <slp-internal.h>
43*0Sstevel@tonic-gate 
44*0Sstevel@tonic-gate #define	IPC_FD_LIFETIME	30
45*0Sstevel@tonic-gate 
46*0Sstevel@tonic-gate /*
47*0Sstevel@tonic-gate  * Cached parameters and thread synchronization
48*0Sstevel@tonic-gate  */
49*0Sstevel@tonic-gate static int slpdfd;			/* cached FD to slpd */
50*0Sstevel@tonic-gate static mutex_t ipc_lock = DEFAULTMUTEX;	/* serializes IPC */
51*0Sstevel@tonic-gate 
52*0Sstevel@tonic-gate /* synch for the FD management thread */
53*0Sstevel@tonic-gate static mutex_t ipc_wait_lock = DEFAULTMUTEX;
54*0Sstevel@tonic-gate static cond_t ipc_wait_var;
55*0Sstevel@tonic-gate static int ipc_used;
56*0Sstevel@tonic-gate static int ipc_thr_running;
57*0Sstevel@tonic-gate 
58*0Sstevel@tonic-gate static struct sockaddr_in *local_sin;	/* slpd addr, set on first use */
59*0Sstevel@tonic-gate 
60*0Sstevel@tonic-gate static SLPError open_ipc();
61*0Sstevel@tonic-gate static void close_ipc();
62*0Sstevel@tonic-gate static void get_localhost_sin();
63*0Sstevel@tonic-gate static void ipc_manage_thr();
64*0Sstevel@tonic-gate 
65*0Sstevel@tonic-gate /*
66*0Sstevel@tonic-gate  * Locking should be handled by the caller
67*0Sstevel@tonic-gate  */
open_ipc()68*0Sstevel@tonic-gate static SLPError open_ipc() {
69*0Sstevel@tonic-gate 	int terr;
70*0Sstevel@tonic-gate 	int retries = 0;
71*0Sstevel@tonic-gate 
72*0Sstevel@tonic-gate 	if (slpdfd)
73*0Sstevel@tonic-gate 		return (SLP_OK);
74*0Sstevel@tonic-gate 
75*0Sstevel@tonic-gate 	/* Make sure the local host's sockaddr_in is set */
76*0Sstevel@tonic-gate 	if (!local_sin) {
77*0Sstevel@tonic-gate 		get_localhost_sin();
78*0Sstevel@tonic-gate 		if (!local_sin) {
79*0Sstevel@tonic-gate 			slpdfd = 0;
80*0Sstevel@tonic-gate 			return (SLP_INTERNAL_SYSTEM_ERROR);
81*0Sstevel@tonic-gate 		}
82*0Sstevel@tonic-gate 	}
83*0Sstevel@tonic-gate 
84*0Sstevel@tonic-gate 	for (;;) {
85*0Sstevel@tonic-gate 	    int errno_kept;
86*0Sstevel@tonic-gate 
87*0Sstevel@tonic-gate 	    if ((slpdfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
88*0Sstevel@tonic-gate 		slp_err(LOG_CRIT, 0, "slp_open_ipc",
89*0Sstevel@tonic-gate 			"could not create socket: %s", strerror(errno));
90*0Sstevel@tonic-gate 		slpdfd = 0;
91*0Sstevel@tonic-gate 		return (SLP_INTERNAL_SYSTEM_ERROR);
92*0Sstevel@tonic-gate 	    }
93*0Sstevel@tonic-gate 
94*0Sstevel@tonic-gate 
95*0Sstevel@tonic-gate 	    if (connect(slpdfd, (struct sockaddr *)local_sin,
96*0Sstevel@tonic-gate 			sizeof (*local_sin)) == 0) {
97*0Sstevel@tonic-gate 		break;
98*0Sstevel@tonic-gate 	    }
99*0Sstevel@tonic-gate 
100*0Sstevel@tonic-gate 	    /* else error condition */
101*0Sstevel@tonic-gate 	    errno_kept = errno; /* in case errno is reset by slp_err */
102*0Sstevel@tonic-gate 	    if (retries++ == 2) {
103*0Sstevel@tonic-gate 		slp_err(LOG_INFO, 0, "slp_open_ipc",
104*0Sstevel@tonic-gate 			"could not connect to slpd: %s", strerror(errno));
105*0Sstevel@tonic-gate 		if (errno_kept == ECONNREFUSED)
106*0Sstevel@tonic-gate 		    slp_err(LOG_INFO, 0, "slp_open_ipc",
107*0Sstevel@tonic-gate 			    "is slpd running?");
108*0Sstevel@tonic-gate 		(void) close(slpdfd);
109*0Sstevel@tonic-gate 		slpdfd = 0;
110*0Sstevel@tonic-gate 		return (SLP_NETWORK_ERROR);
111*0Sstevel@tonic-gate 	    } else {
112*0Sstevel@tonic-gate 		/* back off a little */
113*0Sstevel@tonic-gate 		(void) close(slpdfd);
114*0Sstevel@tonic-gate 		(void) sleep(1);
115*0Sstevel@tonic-gate 	    }
116*0Sstevel@tonic-gate 	}
117*0Sstevel@tonic-gate 
118*0Sstevel@tonic-gate 	/* We now know slpd is reachable; start the management thread */
119*0Sstevel@tonic-gate 	if (!ipc_thr_running) {
120*0Sstevel@tonic-gate 		if ((terr = thr_create(
121*0Sstevel@tonic-gate 			0, NULL,
122*0Sstevel@tonic-gate 			(void *(*)(void *)) ipc_manage_thr,
123*0Sstevel@tonic-gate 			NULL, 0, NULL)) != 0) {
124*0Sstevel@tonic-gate 			slp_err(LOG_CRIT, 0, "slp_open_ipc",
125*0Sstevel@tonic-gate 				"could not start thread: %s",
126*0Sstevel@tonic-gate 				strerror(terr));
127*0Sstevel@tonic-gate 			return (SLP_INTERNAL_SYSTEM_ERROR);
128*0Sstevel@tonic-gate 		}
129*0Sstevel@tonic-gate 	}
130*0Sstevel@tonic-gate 	ipc_thr_running = 1;
131*0Sstevel@tonic-gate 
132*0Sstevel@tonic-gate 	return (SLP_OK);
133*0Sstevel@tonic-gate }
134*0Sstevel@tonic-gate 
close_ipc()135*0Sstevel@tonic-gate static void close_ipc() {
136*0Sstevel@tonic-gate 	(void) mutex_lock(&ipc_lock);
137*0Sstevel@tonic-gate 	if (!slpdfd) {
138*0Sstevel@tonic-gate 		(void) mutex_unlock(&ipc_lock);
139*0Sstevel@tonic-gate 		return;
140*0Sstevel@tonic-gate 	}
141*0Sstevel@tonic-gate 	(void) close(slpdfd);
142*0Sstevel@tonic-gate 	slpdfd = 0;
143*0Sstevel@tonic-gate 	(void) mutex_unlock(&ipc_lock);
144*0Sstevel@tonic-gate }
145*0Sstevel@tonic-gate 
146*0Sstevel@tonic-gate /*
147*0Sstevel@tonic-gate  * Sends 'msg' to slpd, placing the response in 'reply'. Caller should
148*0Sstevel@tonic-gate  * free memory associated with 'reply'. All IPC is handled transparantly
149*0Sstevel@tonic-gate  * by this call. Note that this call is a wrapper for slp_send2slpd_iov.
150*0Sstevel@tonic-gate  * Returns SLP_NETWORK_ERROR if slpd is unreachable, SLP_OK otherwise.
151*0Sstevel@tonic-gate  */
slp_send2slpd(const char * msg,char ** reply)152*0Sstevel@tonic-gate SLPError slp_send2slpd(const char *msg, char **reply) {
153*0Sstevel@tonic-gate 	struct iovec iov[1];
154*0Sstevel@tonic-gate 	iov->iov_base = (caddr_t)msg;
155*0Sstevel@tonic-gate 	iov->iov_len = slp_get_length(msg);
156*0Sstevel@tonic-gate 
157*0Sstevel@tonic-gate 	return (slp_send2slpd_iov(iov, 1, reply));
158*0Sstevel@tonic-gate }
159*0Sstevel@tonic-gate 
slp_send2slpd_iov(struct iovec * msg,int iovlen,char ** reply)160*0Sstevel@tonic-gate SLPError slp_send2slpd_iov(struct iovec *msg, int iovlen, char **reply) {
161*0Sstevel@tonic-gate 	SLPError err;
162*0Sstevel@tonic-gate 	int retries = 0;
163*0Sstevel@tonic-gate 	struct msghdr msghdr[1];
164*0Sstevel@tonic-gate 	struct sigaction new, old;
165*0Sstevel@tonic-gate 
166*0Sstevel@tonic-gate 	*reply = NULL;
167*0Sstevel@tonic-gate 
168*0Sstevel@tonic-gate 	(void) mutex_lock(&ipc_lock);
169*0Sstevel@tonic-gate 	/* is the connection open? */
170*0Sstevel@tonic-gate 	if (!slpdfd) {
171*0Sstevel@tonic-gate 		if ((err = open_ipc()) != SLP_OK) {
172*0Sstevel@tonic-gate 			(void) mutex_unlock(&ipc_lock);
173*0Sstevel@tonic-gate 			return (err);
174*0Sstevel@tonic-gate 		}
175*0Sstevel@tonic-gate 	}
176*0Sstevel@tonic-gate 
177*0Sstevel@tonic-gate 	/* populate the msghdr for sendmsg */
178*0Sstevel@tonic-gate 	msghdr->msg_name = NULL;
179*0Sstevel@tonic-gate 	msghdr->msg_namelen = 0;
180*0Sstevel@tonic-gate 	msghdr->msg_iov = msg;
181*0Sstevel@tonic-gate 	msghdr->msg_iovlen = iovlen;
182*0Sstevel@tonic-gate 	msghdr->msg_accrights = NULL;
183*0Sstevel@tonic-gate 	msghdr->msg_accrightslen = 0;
184*0Sstevel@tonic-gate 
185*0Sstevel@tonic-gate 	/*
186*0Sstevel@tonic-gate 	 * If slpd has been restarted while this connection is
187*0Sstevel@tonic-gate 	 * still open, we will get a SIGPIPE when we try to write
188*0Sstevel@tonic-gate 	 * to it. So we need to ignore SIGPIPEs for the duration of
189*0Sstevel@tonic-gate 	 * the communication with slpd.
190*0Sstevel@tonic-gate 	 */
191*0Sstevel@tonic-gate 	new.sa_handler = SIG_IGN;
192*0Sstevel@tonic-gate 	new.sa_flags = 0;
193*0Sstevel@tonic-gate 	(void) sigemptyset(&new.sa_mask);
194*0Sstevel@tonic-gate 	(void) sigaction(SIGPIPE, &new, &old);	/* preserve old disposition */
195*0Sstevel@tonic-gate 
196*0Sstevel@tonic-gate 	while (sendmsg(slpdfd, msghdr, 0) == -1) {
197*0Sstevel@tonic-gate 		int errno_kept = errno;
198*0Sstevel@tonic-gate 
199*0Sstevel@tonic-gate 		switch (errno) {
200*0Sstevel@tonic-gate 		case EINTR:
201*0Sstevel@tonic-gate 		case ENOBUFS:
202*0Sstevel@tonic-gate 		case ENOSR:
203*0Sstevel@tonic-gate 			continue;
204*0Sstevel@tonic-gate 		case EBADF:
205*0Sstevel@tonic-gate 		case ECONNRESET:
206*0Sstevel@tonic-gate 		case ENOTCONN:
207*0Sstevel@tonic-gate 		default:
208*0Sstevel@tonic-gate 			(void) mutex_unlock(&ipc_lock);
209*0Sstevel@tonic-gate 			close_ipc();
210*0Sstevel@tonic-gate 			if (retries++) {
211*0Sstevel@tonic-gate 				slp_err(LOG_CRIT, 0, "slp_send2slpd",
212*0Sstevel@tonic-gate 					"could not talk to slpd: %s",
213*0Sstevel@tonic-gate 					strerror(errno_kept));
214*0Sstevel@tonic-gate 				err = SLP_NETWORK_ERROR;
215*0Sstevel@tonic-gate 				goto done;
216*0Sstevel@tonic-gate 			}
217*0Sstevel@tonic-gate 			/* try re-opening the connection to slpd */
218*0Sstevel@tonic-gate 			if (open_ipc() == SLP_OK) {
219*0Sstevel@tonic-gate 				(void) mutex_lock(&ipc_lock);
220*0Sstevel@tonic-gate 				continue;
221*0Sstevel@tonic-gate 			} else {
222*0Sstevel@tonic-gate 				err = SLP_NETWORK_ERROR;
223*0Sstevel@tonic-gate 				goto done;
224*0Sstevel@tonic-gate 			}
225*0Sstevel@tonic-gate 		}
226*0Sstevel@tonic-gate 	}
227*0Sstevel@tonic-gate 
228*0Sstevel@tonic-gate 	err = slp_tcp_read(slpdfd, reply);
229*0Sstevel@tonic-gate 
230*0Sstevel@tonic-gate 	/*
231*0Sstevel@tonic-gate 	 * On error slpd may close the socket; there can be a race
232*0Sstevel@tonic-gate 	 * condition here where a following call (attempting to reuse
233*0Sstevel@tonic-gate 	 * the socket) may send to slpd before it has closed the socket.
234*0Sstevel@tonic-gate 	 * To prevent this, we must also close the socket on error.
235*0Sstevel@tonic-gate 	 */
236*0Sstevel@tonic-gate 	if (err == SLP_OK && slp_get_errcode(*reply) != 0) {
237*0Sstevel@tonic-gate 		(void) mutex_unlock(&ipc_lock);
238*0Sstevel@tonic-gate 		close_ipc();
239*0Sstevel@tonic-gate 		(void) mutex_lock(&ipc_lock);
240*0Sstevel@tonic-gate 	}
241*0Sstevel@tonic-gate 
242*0Sstevel@tonic-gate 	/* notify ipc thread of call */
243*0Sstevel@tonic-gate 	(void) mutex_lock(&ipc_wait_lock);
244*0Sstevel@tonic-gate 	ipc_used = 1;
245*0Sstevel@tonic-gate 	(void) cond_signal(&ipc_wait_var);
246*0Sstevel@tonic-gate 	(void) mutex_unlock(&ipc_wait_lock);
247*0Sstevel@tonic-gate 
248*0Sstevel@tonic-gate 	(void) mutex_unlock(&ipc_lock);
249*0Sstevel@tonic-gate 
250*0Sstevel@tonic-gate done:
251*0Sstevel@tonic-gate 	/* restore original signal disposition for SIGPIPE */
252*0Sstevel@tonic-gate 	(void) sigaction(SIGPIPE, &old, NULL);
253*0Sstevel@tonic-gate 	return (err);
254*0Sstevel@tonic-gate }
255*0Sstevel@tonic-gate 
256*0Sstevel@tonic-gate /*
257*0Sstevel@tonic-gate  * Sets up a sockaddr_in pointing at slpd.
258*0Sstevel@tonic-gate  * After the first call, the address of slpd is cached in local_sin.
259*0Sstevel@tonic-gate  *
260*0Sstevel@tonic-gate  * side effect: local_sin is set to an address for slpd.
261*0Sstevel@tonic-gate  */
get_localhost_sin()262*0Sstevel@tonic-gate static void get_localhost_sin() {
263*0Sstevel@tonic-gate 	struct sockaddr_in *sin;
264*0Sstevel@tonic-gate 	static mutex_t lhlock = DEFAULTMUTEX;
265*0Sstevel@tonic-gate 
266*0Sstevel@tonic-gate 	(void) mutex_lock(&lhlock);
267*0Sstevel@tonic-gate 	if (local_sin) {
268*0Sstevel@tonic-gate 		(void) mutex_unlock(&lhlock);
269*0Sstevel@tonic-gate 		return;
270*0Sstevel@tonic-gate 	}
271*0Sstevel@tonic-gate 
272*0Sstevel@tonic-gate 	if (!(sin = calloc(1, sizeof (*sin)))) {
273*0Sstevel@tonic-gate 		slp_err(LOG_CRIT, 0, "get_localhost_sin", "out of memory");
274*0Sstevel@tonic-gate 		goto done;
275*0Sstevel@tonic-gate 	}
276*0Sstevel@tonic-gate 
277*0Sstevel@tonic-gate 	IN_SET_LOOPBACK_ADDR(sin);
278*0Sstevel@tonic-gate 	sin->sin_family = AF_INET;
279*0Sstevel@tonic-gate 	sin->sin_port = htons(SLP_PORT);
280*0Sstevel@tonic-gate 
281*0Sstevel@tonic-gate done:
282*0Sstevel@tonic-gate 	local_sin = sin;
283*0Sstevel@tonic-gate 	(void) mutex_unlock(&lhlock);
284*0Sstevel@tonic-gate }
285*0Sstevel@tonic-gate 
286*0Sstevel@tonic-gate /*
287*0Sstevel@tonic-gate  * IPC management: the FD to slpd is kept open and cached to improve
288*0Sstevel@tonic-gate  * performance on successive calls. The IPC management thread waits
289*0Sstevel@tonic-gate  * on a condition variable; the condition is if an IPC call has been
290*0Sstevel@tonic-gate  * made. If so, the thread advances the FD's expiration by IPC_FD_LIFETIME
291*0Sstevel@tonic-gate  * and continues waiting for the next IPC call. After the FD has expired,
292*0Sstevel@tonic-gate  * the thread closes IPC and shuts itself down.
293*0Sstevel@tonic-gate  */
ipc_manage_thr()294*0Sstevel@tonic-gate static void ipc_manage_thr() {
295*0Sstevel@tonic-gate 	timestruc_t timeout;
296*0Sstevel@tonic-gate 
297*0Sstevel@tonic-gate 	timeout.tv_nsec = 0;
298*0Sstevel@tonic-gate 	(void) mutex_lock(&ipc_wait_lock);
299*0Sstevel@tonic-gate 	ipc_used = 0;
300*0Sstevel@tonic-gate 
301*0Sstevel@tonic-gate 	while (ipc_used == 0) {
302*0Sstevel@tonic-gate 		int err;
303*0Sstevel@tonic-gate 
304*0Sstevel@tonic-gate 		timeout.tv_sec = IPC_FD_LIFETIME;
305*0Sstevel@tonic-gate 		err = cond_reltimedwait(&ipc_wait_var, &ipc_wait_lock,
306*0Sstevel@tonic-gate 			&timeout);
307*0Sstevel@tonic-gate 
308*0Sstevel@tonic-gate 		if (err == ETIME) {
309*0Sstevel@tonic-gate 			/* shutdown */
310*0Sstevel@tonic-gate 			close_ipc();
311*0Sstevel@tonic-gate 			ipc_thr_running = 0;
312*0Sstevel@tonic-gate 			(void) mutex_unlock(&ipc_wait_lock);
313*0Sstevel@tonic-gate 			thr_exit(NULL);
314*0Sstevel@tonic-gate 		} else {
315*0Sstevel@tonic-gate 			/* reset condition variable */
316*0Sstevel@tonic-gate 			ipc_used = 0;
317*0Sstevel@tonic-gate 		}
318*0Sstevel@tonic-gate 	}
319*0Sstevel@tonic-gate }
320