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vacation.c revision 1.20 
      1 /*	$NetBSD: vacation.c,v 1.20 2003/02/18 19:21:33 perry Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1983, 1987, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 
     38 #ifndef lint
     39 __COPYRIGHT("@(#) Copyright (c) 1983, 1987, 1993\n\
     40 	The Regents of the University of California.  All rights reserved.\n");
     41 #endif /* not lint */
     42 
     43 #ifndef lint
     44 #if 0
     45 static char sccsid[] = "@(#)vacation.c	8.2 (Berkeley) 1/26/94";
     46 #endif
     47 __RCSID("$NetBSD: vacation.c,v 1.20 2003/02/18 19:21:33 perry Exp $");
     48 #endif /* not lint */
     49 
     50 /*
     51 **  Vacation
     52 **  Copyright (c) 1983  Eric P. Allman
     53 **  Berkeley, California
     54 */
     55 
     56 #include <sys/param.h>
     57 #include <sys/stat.h>
     58 
     59 #include <ctype.h>
     60 #include <db.h>
     61 #include <errno.h>
     62 #include <fcntl.h>
     63 #include <paths.h>
     64 #include <pwd.h>
     65 #include <stdio.h>
     66 #include <stdlib.h>
     67 #include <string.h>
     68 #include <syslog.h>
     69 #include <time.h>
     70 #include <tzfile.h>
     71 #include <unistd.h>
     72 
     73 /*
     74  *  VACATION -- return a message to the sender when on vacation.
     75  *
     76  *	This program is invoked as a message receiver.  It returns a
     77  *	message specified by the user to whomever sent the mail, taking
     78  *	care not to return a message too often to prevent "I am on
     79  *	vacation" loops.
     80  */
     81 
     82 #define	MAXLINE	1024			/* max line from mail header */
     83 #define	VDB	".vacation.db"		/* dbm's database */
     84 #define	VMSG	".vacation.msg"		/* vacation message */
     85 
     86 typedef struct alias {
     87 	struct alias *next;
     88 	const char *name;
     89 } alias_t;
     90 alias_t *names;
     91 
     92 DB *db;
     93 char from[MAXLINE];
     94 
     95 int main(int, char **);
     96 int junkmail(void);
     97 int nsearch(const char *, const char *);
     98 void readheaders(void);
     99 int recent(void);
    100 void sendmessage(const char *);
    101 void setinterval(time_t);
    102 void setreply(void);
    103 void usage(void);
    104 
    105 int
    106 main(int argc, char **argv)
    107 {
    108 	struct passwd *pw;
    109 	alias_t *cur;
    110 	time_t interval;
    111 	int ch, iflag;
    112 
    113 	opterr = iflag = 0;
    114 	interval = -1;
    115 	openlog("vacation", 0, LOG_USER);
    116 	while ((ch = getopt(argc, argv, "a:Iir:")) != -1)
    117 		switch((char)ch) {
    118 		case 'a':			/* alias */
    119 			if (!(cur = (alias_t *)malloc((size_t)sizeof(alias_t))))
    120 				break;
    121 			cur->name = optarg;
    122 			cur->next = names;
    123 			names = cur;
    124 			break;
    125 		case 'I':			/* backward compatible */
    126 		case 'i':			/* init the database */
    127 			iflag = 1;
    128 			break;
    129 		case 'r':
    130 			if (isdigit((unsigned char)*optarg)) {
    131 				interval = atol(optarg) * SECSPERDAY;
    132 				if (interval < 0)
    133 					usage();
    134 			}
    135 			else
    136 				interval = (time_t)LONG_MAX;	/* XXX */
    137 			break;
    138 		case '?':
    139 		default:
    140 			usage();
    141 		}
    142 	argc -= optind;
    143 	argv += optind;
    144 
    145 	if (argc != 1) {
    146 		if (!iflag)
    147 			usage();
    148 		if (!(pw = getpwuid(getuid()))) {
    149 			syslog(LOG_ERR,
    150 			    "vacation: no such user uid %u.", getuid());
    151 			exit(1);
    152 		}
    153 	}
    154 	else if (!(pw = getpwnam(*argv))) {
    155 		syslog(LOG_ERR, "vacation: no such user %s.", *argv);
    156 		exit(1);
    157 	}
    158 	if (chdir(pw->pw_dir)) {
    159 		syslog(LOG_ERR,
    160 		    "vacation: no such directory %s.", pw->pw_dir);
    161 		exit(1);
    162 	}
    163 
    164 	db = dbopen(VDB, O_CREAT|O_RDWR | (iflag ? O_TRUNC : 0),
    165 	    S_IRUSR|S_IWUSR, DB_HASH, NULL);
    166 	if (!db) {
    167 		syslog(LOG_ERR, "vacation: %s: %m", VDB);
    168 		exit(1);
    169 	}
    170 
    171 	if (interval != -1)
    172 		setinterval(interval);
    173 
    174 	if (iflag) {
    175 		(void)(db->close)(db);
    176 		exit(0);
    177 	}
    178 
    179 	if (!(cur = malloc((size_t)sizeof(alias_t))))
    180 		exit(1);
    181 	cur->name = pw->pw_name;
    182 	cur->next = names;
    183 	names = cur;
    184 
    185 	readheaders();
    186 	if (!recent()) {
    187 		setreply();
    188 		(void)(db->close)(db);
    189 		sendmessage(pw->pw_name);
    190 	}
    191 	else
    192 		(void)(db->close)(db);
    193 	exit(0);
    194 	/* NOTREACHED */
    195 }
    196 
    197 /*
    198  * readheaders --
    199  *	read mail headers
    200  */
    201 void
    202 readheaders(void)
    203 {
    204 	alias_t *cur;
    205 	char *p;
    206 	int tome, cont;
    207 	char buf[MAXLINE];
    208 
    209 	cont = tome = 0;
    210 	while (fgets(buf, sizeof(buf), stdin) && *buf != '\n')
    211 		switch(*buf) {
    212 		case 'F':		/* "From " */
    213 			cont = 0;
    214 			if (!strncmp(buf, "From ", 5)) {
    215 				for (p = buf + 5; *p && *p != ' '; ++p);
    216 				*p = '\0';
    217 				(void)strcpy(from, buf + 5);
    218 				if ((p = strchr(from, '\n')))
    219 					*p = '\0';
    220 				if (junkmail())
    221 					exit(0);
    222 			}
    223 			break;
    224 		case 'P':		/* "Precedence:" */
    225 			cont = 0;
    226 			if (strncasecmp(buf, "Precedence", 10) ||
    227 			    (buf[10] != ':' && buf[10] != ' ' &&
    228 			    buf[10] != '\t'))
    229 				break;
    230 			if (!(p = strchr(buf, ':')))
    231 				break;
    232 			while (*++p && isspace((unsigned char)*p));
    233 			if (!*p)
    234 				break;
    235 			if (!strncasecmp(p, "junk", 4) ||
    236 			    !strncasecmp(p, "bulk", 4) ||
    237 			    !strncasecmp(p, "list", 4))
    238 				exit(0);
    239 			break;
    240 		case 'C':		/* "Cc:" */
    241 			if (strncmp(buf, "Cc:", 3))
    242 				break;
    243 			cont = 1;
    244 			goto findme;
    245 		case 'T':		/* "To:" */
    246 			if (strncmp(buf, "To:", 3))
    247 				break;
    248 			cont = 1;
    249 			goto findme;
    250 		default:
    251 			if (!isspace((unsigned char)*buf) || !cont || tome) {
    252 				cont = 0;
    253 				break;
    254 			}
    255 findme:			for (cur = names; !tome && cur; cur = cur->next)
    256 				tome += nsearch(cur->name, buf);
    257 		}
    258 	if (!tome)
    259 		exit(0);
    260 	if (!*from) {
    261 		syslog(LOG_ERR, "vacation: no initial \"From\" line.");
    262 		exit(1);
    263 	}
    264 }
    265 
    266 /*
    267  * nsearch --
    268  *	do a nice, slow, search of a string for a substring.
    269  */
    270 int
    271 nsearch(const char *name, const char *str)
    272 {
    273 	size_t len;
    274 
    275 	for (len = strlen(name); *str; ++str)
    276 		if (!strncasecmp(name, str, len))
    277 			return(1);
    278 	return(0);
    279 }
    280 
    281 /*
    282  * junkmail --
    283  *	read the header and return if automagic/junk/bulk/list mail
    284  */
    285 int
    286 junkmail(void)
    287 {
    288 	static struct ignore {
    289 		char	*name;
    290 		int	len;
    291 	} ignore[] = {
    292 		{ "-request", 8 },
    293 		{ "postmaster", 10 },
    294 		{ "uucp", 4 },
    295 		{ "mailer-daemon", 13 },
    296 		{ "mailer", 6 },
    297 		{ "-relay", 6 },
    298 		{NULL, 0 }
    299 	};
    300 	struct ignore *cur;
    301 	int len;
    302 	char *p;
    303 
    304 	/*
    305 	 * This is mildly amusing, and I'm not positive it's right; trying
    306 	 * to find the "real" name of the sender, assuming that addresses
    307 	 * will be some variant of:
    308 	 *
    309 	 * From site!site!SENDER%site.domain%site.domain (at) site.domain
    310 	 */
    311 	if (!(p = strchr(from, '%')))
    312 		if (!(p = strchr(from, '@'))) {
    313 			if ((p = strrchr(from, '!')))
    314 				++p;
    315 			else
    316 				p = from;
    317 			for (; *p; ++p);
    318 		}
    319 	len = p - from;
    320 	for (cur = ignore; cur->name; ++cur)
    321 		if (len >= cur->len &&
    322 		    !strncasecmp(cur->name, p - cur->len, cur->len))
    323 			return(1);
    324 	return(0);
    325 }
    326 
    327 #define	VIT	"__VACATION__INTERVAL__TIMER__"
    328 
    329 /*
    330  * recent --
    331  *	find out if user has gotten a vacation message recently.
    332  *	use memmove for machines with alignment restrictions
    333  */
    334 int
    335 recent(void)
    336 {
    337 	DBT key, data;
    338 	time_t then, next;
    339 
    340 	/* get interval time */
    341 	key.data = VIT;
    342 	key.size = sizeof(VIT);
    343 	if ((db->get)(db, &key, &data, 0))
    344 		next = SECSPERDAY * DAYSPERWEEK;
    345 	else
    346 		memmove(&next, data.data, sizeof(next));
    347 
    348 	/* get record for this address */
    349 	key.data = from;
    350 	key.size = strlen(from);
    351 	if (!(db->get)(db, &key, &data, 0)) {
    352 		memmove(&then, data.data, sizeof(then));
    353 		if (next == (time_t)LONG_MAX ||			/* XXX */
    354 		    then + next > time(NULL))
    355 			return(1);
    356 	}
    357 	return(0);
    358 }
    359 
    360 /*
    361  * setinterval --
    362  *	store the reply interval
    363  */
    364 void
    365 setinterval(time_t interval)
    366 {
    367 	DBT key, data;
    368 
    369 	key.data = VIT;
    370 	key.size = sizeof(VIT);
    371 	data.data = &interval;
    372 	data.size = sizeof(interval);
    373 	(void)(db->put)(db, &key, &data, 0);
    374 }
    375 
    376 /*
    377  * setreply --
    378  *	store that this user knows about the vacation.
    379  */
    380 void
    381 setreply(void)
    382 {
    383 	DBT key, data;
    384 	time_t now;
    385 
    386 	key.data = from;
    387 	key.size = strlen(from);
    388 	(void)time(&now);
    389 	data.data = &now;
    390 	data.size = sizeof(now);
    391 	(void)(db->put)(db, &key, &data, 0);
    392 }
    393 
    394 /*
    395  * sendmessage --
    396  *	exec sendmail to send the vacation file to sender
    397  */
    398 void
    399 sendmessage(const char *myname)
    400 {
    401 	FILE *mfp, *sfp;
    402 	int i;
    403 	int pvect[2];
    404 	char buf[MAXLINE];
    405 
    406 	mfp = fopen(VMSG, "r");
    407 	if (mfp == NULL) {
    408 		syslog(LOG_ERR, "vacation: no ~%s/%s file.", myname, VMSG);
    409 		exit(1);
    410 	}
    411 	if (pipe(pvect) < 0) {
    412 		syslog(LOG_ERR, "vacation: pipe: %m");
    413 		exit(1);
    414 	}
    415 	i = vfork();
    416 	if (i < 0) {
    417 		syslog(LOG_ERR, "vacation: fork: %m");
    418 		exit(1);
    419 	}
    420 	if (i == 0) {
    421 		dup2(pvect[0], 0);
    422 		close(pvect[0]);
    423 		close(pvect[1]);
    424 		close(fileno(mfp));
    425 		execl(_PATH_SENDMAIL, "sendmail", "-f", myname, "--", from,
    426 		    NULL);
    427 		syslog(LOG_ERR, "vacation: can't exec %s: %m",
    428 		    _PATH_SENDMAIL);
    429 		_exit(1);
    430 	}
    431 	close(pvect[0]);
    432 	sfp = fdopen(pvect[1], "w");
    433 	fprintf(sfp, "To: %s\n", from);
    434 	while (fgets(buf, sizeof buf, mfp))
    435 		fputs(buf, sfp);
    436 	fclose(mfp);
    437 	fclose(sfp);
    438 }
    439 
    440 void
    441 usage(void)
    442 {
    443 
    444 	syslog(LOG_ERR, "uid %u: usage: vacation [-i] [-a alias] login",
    445 	    getuid());
    446 	exit(1);
    447 }
    448