rbootd.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1988, 1992 The University of Utah and the Center
5 *	for Software Science (CSS).
6 * Copyright (c) 1992, 1993
7 *	The Regents of the University of California.  All rights reserved.
8 *
9 * This code is derived from software contributed to Berkeley by
10 * the Center for Software Science of the University of Utah Computer
11 * Science Department.  CSS requests users of this software to return
12 * to css-dist@cs.utah.edu any improvements that they make and grant
13 * CSS redistribution rights.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 *    notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 *    notice, this list of conditions and the following disclaimer in the
22 *    documentation and/or other materials provided with the distribution.
23 * 3. Neither the name of the University nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 *	from: @(#)rbootd.c	8.1 (Berkeley) 6/4/93
40 *
41 * From: Utah Hdr: rbootd.c 3.1 92/07/06
42 * Author: Jeff Forys, University of Utah CSS
43 */
44
45#ifndef lint
46static const char copyright[] =
47"@(#) Copyright (c) 1992, 1993\n\
48	The Regents of the University of California.  All rights reserved.\n";
49#endif /* not lint */
50
51#ifndef lint
52#if 0
53static const char sccsid[] = "@(#)rbootd.c	8.1 (Berkeley) 6/4/93";
54#endif
55#endif /* not lint */
56#include <sys/cdefs.h>
57__FBSDID("$FreeBSD: stable/11/libexec/rbootd/rbootd.c 330897 2018-03-14 03:19:51Z eadler $");
58
59#include <sys/param.h>
60#include <sys/time.h>
61#include <ctype.h>
62#include <err.h>
63#include <errno.h>
64#include <fcntl.h>
65#include <signal.h>
66#include <stdio.h>
67#include <stdlib.h>
68#include <string.h>
69#include <syslog.h>
70#include <unistd.h>
71#include "defs.h"
72
73static void usage(void);
74
75int
76main(int argc, char *argv[])
77{
78	int c, fd, omask, maxfds;
79	fd_set rset;
80
81	/*
82	 *  Close any open file descriptors.
83	 *  Temporarily leave stdin & stdout open for `-d',
84	 *  and stderr open for any pre-syslog error messages.
85	 */
86	{
87		int i, nfds = getdtablesize();
88
89		for (i = 0; i < nfds; i++)
90			if (i != fileno(stdin) && i != fileno(stdout) &&
91			    i != fileno(stderr))
92				(void) close(i);
93	}
94
95	/*
96	 *  Parse any arguments.
97	 */
98	while ((c = getopt(argc, argv, "adi:")) != -1)
99		switch(c) {
100		    case 'a':
101			BootAny++;
102			break;
103		    case 'd':
104			DebugFlg++;
105			break;
106		    case 'i':
107			IntfName = optarg;
108			break;
109		    default:
110			usage();
111		}
112	for (; optind < argc; optind++) {
113		if (ConfigFile == NULL)
114			ConfigFile = argv[optind];
115		else {
116			warnx("too many config files (`%s' ignored)",
117			    argv[optind]);
118		}
119	}
120
121	if (ConfigFile == NULL)			/* use default config file */
122		ConfigFile = DfltConfig;
123
124	if (DebugFlg) {
125		DbgFp = stdout;				/* output to stdout */
126
127		(void) signal(SIGUSR1, SIG_IGN);	/* dont muck w/DbgFp */
128		(void) signal(SIGUSR2, SIG_IGN);
129		(void) fclose(stderr);			/* finished with it */
130	} else {
131		if (daemon(0, 0))
132			err(1, "can't detach from terminal");
133
134		(void) signal(SIGUSR1, DebugOn);
135		(void) signal(SIGUSR2, DebugOff);
136	}
137
138	openlog("rbootd", LOG_PID, LOG_DAEMON);
139
140	/*
141	 *  If no interface was specified, get one now.
142	 *
143	 *  This is convoluted because we want to get the default interface
144	 *  name for the syslog("restarted") message.  If BpfGetIntfName()
145	 *  runs into an error, it will return a syslog-able error message
146	 *  (in `errmsg') which will be displayed here.
147	 */
148	if (IntfName == NULL) {
149		char *errmsg;
150
151		if ((IntfName = BpfGetIntfName(&errmsg)) == NULL) {
152			/* Backslash to avoid trigraph '??)'. */
153			syslog(LOG_NOTICE, "restarted (?\?)");
154			/* BpfGetIntfName() returns safe names, using %m */
155			syslog(LOG_ERR, "%s", errmsg);
156			Exit(0);
157		}
158	}
159
160	syslog(LOG_NOTICE, "restarted (%s)", IntfName);
161
162	(void) signal(SIGHUP, ReConfig);
163	(void) signal(SIGINT, Exit);
164	(void) signal(SIGTERM, Exit);
165
166	/*
167	 *  Grab our host name and pid.
168	 */
169	if (gethostname(MyHost, MAXHOSTNAMELEN - 1) < 0) {
170		syslog(LOG_ERR, "gethostname: %m");
171		Exit(0);
172	}
173	MyHost[MAXHOSTNAMELEN - 1] = '\0';
174
175	MyPid = getpid();
176
177	/*
178	 *  Write proc's pid to a file.
179	 */
180	{
181		FILE *fp;
182
183		if ((fp = fopen(PidFile, "w")) != NULL) {
184			(void) fprintf(fp, "%d\n", (int) MyPid);
185			(void) fclose(fp);
186		} else {
187			syslog(LOG_WARNING, "fopen: failed (%s)", PidFile);
188		}
189	}
190
191	/*
192	 *  All boot files are relative to the boot directory, we might
193	 *  as well chdir() there to make life easier.
194	 */
195	if (chdir(BootDir) < 0) {
196		syslog(LOG_ERR, "chdir: %m (%s)", BootDir);
197		Exit(0);
198	}
199
200	/*
201	 *  Initial configuration.
202	 */
203	omask = sigblock(sigmask(SIGHUP));	/* prevent reconfig's */
204	if (GetBootFiles() == 0)		/* get list of boot files */
205		Exit(0);
206	if (ParseConfig() == 0)			/* parse config file */
207		Exit(0);
208
209	/*
210	 *  Open and initialize a BPF device for the appropriate interface.
211	 *  If an error is encountered, a message is displayed and Exit()
212	 *  is called.
213	 */
214	fd = BpfOpen();
215
216	(void) sigsetmask(omask);		/* allow reconfig's */
217
218	/*
219	 *  Main loop: receive a packet, determine where it came from,
220	 *  and if we service this host, call routine to handle request.
221	 */
222	maxfds = fd + 1;
223	FD_ZERO(&rset);
224	FD_SET(fd, &rset);
225	for (;;) {
226		struct timeval timeout;
227		fd_set r;
228		int nsel;
229
230		r = rset;
231
232		if (RmpConns == NULL) {		/* timeout isn't necessary */
233			nsel = select(maxfds, &r, NULL, NULL, NULL);
234		} else {
235			timeout.tv_sec = RMP_TIMEOUT;
236			timeout.tv_usec = 0;
237			nsel = select(maxfds, &r, NULL, NULL, &timeout);
238		}
239
240		if (nsel < 0) {
241			if (errno == EINTR)
242				continue;
243			syslog(LOG_ERR, "select: %m");
244			Exit(0);
245		} else if (nsel == 0) {		/* timeout */
246			DoTimeout();			/* clear stale conns */
247			continue;
248		}
249
250		if (FD_ISSET(fd, &r)) {
251			RMPCONN rconn;
252			CLIENT *client, *FindClient();
253			int doread = 1;
254
255			while (BpfRead(&rconn, doread)) {
256				doread = 0;
257
258				if (DbgFp != NULL)	/* display packet */
259					DispPkt(&rconn,DIR_RCVD);
260
261				omask = sigblock(sigmask(SIGHUP));
262
263				/*
264				 *  If we do not restrict service, set the
265				 *  client to NULL (ProcessPacket() handles
266				 *  this).  Otherwise, check that we can
267				 *  service this host; if not, log a message
268				 *  and ignore the packet.
269				 */
270				if (BootAny) {
271					client = NULL;
272				} else if ((client=FindClient(&rconn))==NULL) {
273					syslog(LOG_INFO,
274					       "%s: boot packet ignored",
275					       EnetStr(&rconn));
276					(void) sigsetmask(omask);
277					continue;
278				}
279
280				ProcessPacket(&rconn,client);
281
282				(void) sigsetmask(omask);
283			}
284		}
285	}
286}
287
288static void
289usage(void)
290{
291	fprintf(stderr, "usage: rbootd [-ad] [-i interface] [config_file]\n");
292	exit (1);
293}
294
295/*
296**  DoTimeout -- Free any connections that have timed out.
297**
298**	Parameters:
299**		None.
300**
301**	Returns:
302**		Nothing.
303**
304**	Side Effects:
305**		- Timed out connections in `RmpConns' will be freed.
306*/
307void
308DoTimeout(void)
309{
310	RMPCONN *rtmp;
311	time_t now;
312
313	/*
314	 *  For each active connection, if RMP_TIMEOUT seconds have passed
315	 *  since the last packet was sent, delete the connection.
316	 */
317	now = time(NULL);
318	for (rtmp = RmpConns; rtmp != NULL; rtmp = rtmp->next)
319		if ((rtmp->tstamp.tv_sec + RMP_TIMEOUT) < now) {
320			syslog(LOG_WARNING, "%s: connection timed out (%u)",
321			       EnetStr(rtmp), rtmp->rmp.r_type);
322			RemoveConn(rtmp);
323		}
324}
325
326/*
327**  FindClient -- Find client associated with a packet.
328**
329**	Parameters:
330**		rconn - the new packet.
331**
332**	Returns:
333**		Pointer to client info if found, NULL otherwise.
334**
335**	Side Effects:
336**		None.
337**
338**	Warnings:
339**		- This routine must be called with SIGHUP blocked since
340**		  a reconfigure can invalidate the information returned.
341*/
342
343CLIENT *
344FindClient(RMPCONN *rconn)
345{
346	CLIENT *ctmp;
347
348	for (ctmp = Clients; ctmp != NULL; ctmp = ctmp->next)
349		if (bcmp((char *)&rconn->rmp.hp_hdr.saddr[0],
350		         (char *)&ctmp->addr[0], RMP_ADDRLEN) == 0)
351			break;
352
353	return(ctmp);
354}
355
356/*
357**  Exit -- Log an error message and exit.
358**
359**	Parameters:
360**		sig - caught signal (or zero if not dying on a signal).
361**
362**	Returns:
363**		Does not return.
364**
365**	Side Effects:
366**		- This process ceases to exist.
367*/
368void
369Exit(int sig)
370{
371	if (sig > 0)
372		syslog(LOG_ERR, "going down on signal %d", sig);
373	else
374		syslog(LOG_ERR, "going down with fatal error");
375	BpfClose();
376	exit(1);
377}
378
379/*
380**  ReConfig -- Get new list of boot files and reread config files.
381**
382**	Parameters:
383**		None.
384**
385**	Returns:
386**		Nothing.
387**
388**	Side Effects:
389**		- All active connections are dropped.
390**		- List of boot-able files is changed.
391**		- List of clients is changed.
392**
393**	Warnings:
394**		- This routine must be called with SIGHUP blocked.
395*/
396void
397ReConfig(int signo __unused)
398{
399	syslog(LOG_NOTICE, "reconfiguring boot server");
400
401	FreeConns();
402
403	if (GetBootFiles() == 0)
404		Exit(0);
405
406	if (ParseConfig() == 0)
407		Exit(0);
408}
409
410/*
411**  DebugOff -- Turn off debugging.
412**
413**	Parameters:
414**		None.
415**
416**	Returns:
417**		Nothing.
418**
419**	Side Effects:
420**		- Debug file is closed.
421*/
422void
423DebugOff(int signo __unused)
424{
425	if (DbgFp != NULL)
426		(void) fclose(DbgFp);
427
428	DbgFp = NULL;
429}
430
431/*
432**  DebugOn -- Turn on debugging.
433**
434**	Parameters:
435**		None.
436**
437**	Returns:
438**		Nothing.
439**
440**	Side Effects:
441**		- Debug file is opened/truncated if not already opened,
442**		  otherwise do nothing.
443*/
444void
445DebugOn(int signo __unused)
446{
447	if (DbgFp == NULL) {
448		if ((DbgFp = fopen(DbgFile, "w")) == NULL)
449			syslog(LOG_ERR, "can't open debug file (%s)", DbgFile);
450	}
451}
452