comsat.c revision 50476 
1/*
2 * Copyright (c) 1980, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35static const char copyright[] =
36"@(#) Copyright (c) 1980, 1993\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41#if 0
42static char sccsid[] = "@(#)comsat.c	8.1 (Berkeley) 6/4/93";
43#endif
44static const char rcsid[] =
45  "$FreeBSD: head/libexec/comsat/comsat.c 50476 1999-08-28 00:22:10Z peter $";
46#endif /* not lint */
47
48#include <sys/param.h>
49#include <sys/socket.h>
50#include <sys/stat.h>
51#include <sys/file.h>
52#include <sys/wait.h>
53
54#include <netinet/in.h>
55
56#include <ctype.h>
57#include <err.h>
58#include <errno.h>
59#include <netdb.h>
60#include <paths.h>
61#include <pwd.h>
62#include <termios.h>
63#include <signal.h>
64#include <stdio.h>
65#include <stdlib.h>
66#include <string.h>
67#include <syslog.h>
68#include <unistd.h>
69#include <utmp.h>
70
71int	debug = 0;
72#define	dsyslog	if (debug) syslog
73
74#define MAXIDLE	120
75
76char	hostname[MAXHOSTNAMELEN];
77struct	utmp *utmp = NULL;
78time_t	lastmsgtime;
79int	nutmp, uf;
80
81void jkfprintf __P((FILE *, char[], char[], off_t));
82void mailfor __P((char *));
83void notify __P((struct utmp *, char[], off_t, int));
84void onalrm __P((int));
85void reapchildren __P((int));
86
87int
88main(argc, argv)
89	int argc;
90	char *argv[];
91{
92	struct sockaddr_in from;
93	register int cc;
94	int fromlen;
95	char msgbuf[256];
96
97	/* verify proper invocation */
98	fromlen = sizeof(from);
99	if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0)
100		err(1, "getsockname");
101	openlog("comsat", LOG_PID, LOG_DAEMON);
102	if (chdir(_PATH_MAILDIR)) {
103		syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR);
104		(void) recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
105		exit(1);
106	}
107	if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) {
108		syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP);
109		(void) recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
110		exit(1);
111	}
112	(void)time(&lastmsgtime);
113	(void)gethostname(hostname, sizeof(hostname));
114	onalrm(0);
115	(void)signal(SIGALRM, onalrm);
116	(void)signal(SIGTTOU, SIG_IGN);
117	(void)signal(SIGCHLD, reapchildren);
118	for (;;) {
119		cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
120		if (cc <= 0) {
121			if (errno != EINTR)
122				sleep(1);
123			errno = 0;
124			continue;
125		}
126		if (!nutmp)		/* no one has logged in yet */
127			continue;
128		sigblock(sigmask(SIGALRM));
129		msgbuf[cc] = '\0';
130		(void)time(&lastmsgtime);
131		mailfor(msgbuf);
132		sigsetmask(0L);
133	}
134}
135
136void
137reapchildren(signo)
138	int signo;
139{
140	while (wait3(NULL, WNOHANG, NULL) > 0);
141}
142
143void
144onalrm(signo)
145	int signo;
146{
147	static u_int utmpsize;		/* last malloced size for utmp */
148	static u_int utmpmtime;		/* last modification time for utmp */
149	struct stat statbf;
150
151	if (time(NULL) - lastmsgtime >= MAXIDLE)
152		exit(0);
153	(void)alarm((u_int)15);
154	(void)fstat(uf, &statbf);
155	if (statbf.st_mtime > utmpmtime) {
156		utmpmtime = statbf.st_mtime;
157		if (statbf.st_size > utmpsize) {
158			utmpsize = statbf.st_size + 10 * sizeof(struct utmp);
159			if ((utmp = realloc(utmp, utmpsize)) == NULL) {
160				syslog(LOG_ERR, "%s", strerror(errno));
161				exit(1);
162			}
163		}
164		(void)lseek(uf, (off_t)0, L_SET);
165		nutmp = read(uf, utmp, (int)statbf.st_size)/sizeof(struct utmp);
166	}
167}
168
169void
170mailfor(name)
171	char *name;
172{
173	register struct utmp *utp = &utmp[nutmp];
174	register char *cp;
175	char *file;
176	off_t offset;
177	int folder;
178	char buf[sizeof(_PATH_MAILDIR) + sizeof(utmp[0].ut_name) + 1];
179	char buf2[sizeof(_PATH_MAILDIR) + sizeof(utmp[0].ut_name) + 1];
180
181	if (!(cp = strchr(name, '@')))
182		return;
183	*cp = '\0';
184	offset = atoi(cp + 1);
185	if (!(cp = strchr(cp + 1, ':')))
186		file = name;
187	else
188		file = cp + 1;
189	sprintf(buf, "%s/%.*s", _PATH_MAILDIR, (int)sizeof(utmp[0].ut_name),
190	    name);
191	if (*file != '/') {
192		sprintf(buf2, "%s/%.*s", _PATH_MAILDIR,
193		    (int)sizeof(utmp[0].ut_name), file);
194		file = buf2;
195	}
196	folder = strcmp(buf, file);
197	while (--utp >= utmp)
198		if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name)))
199			notify(utp, file, offset, folder);
200}
201
202static char *cr;
203
204void
205notify(utp, file, offset, folder)
206	register struct utmp *utp;
207	char file[];
208	off_t offset;
209	int folder;
210{
211	FILE *tp;
212	struct stat stb;
213	struct termios tio;
214	char tty[20], name[sizeof(utmp[0].ut_name) + 1];
215
216	(void)snprintf(tty, sizeof(tty), "%s%.*s",
217	    _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line);
218	if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) {
219		/* A slash is an attempt to break security... */
220		syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty);
221		return;
222	}
223	if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) {
224		dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty);
225		return;
226	}
227	dsyslog(LOG_DEBUG, "notify %s on %s\n", utp->ut_name, tty);
228	if (fork())
229		return;
230	(void)signal(SIGALRM, SIG_DFL);
231	(void)alarm((u_int)30);
232	if ((tp = fopen(tty, "w")) == NULL) {
233		dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno));
234		_exit(1);
235	}
236	(void)tcgetattr(fileno(tp), &tio);
237	cr = ((tio.c_oflag & (OPOST|ONLCR)) == (OPOST|ONLCR)) ?  "\n" : "\n\r";
238	(void)strncpy(name, utp->ut_name, sizeof(utp->ut_name));
239	name[sizeof(name) - 1] = '\0';
240	(void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived%s%s%s:%s----%s",
241	    cr, name, (int)sizeof(hostname), hostname,
242	    folder ? cr : "", folder ? "to " : "", folder ? file : "",
243	    cr, cr);
244	jkfprintf(tp, name, file, offset);
245	(void)fclose(tp);
246	_exit(0);
247}
248
249void
250jkfprintf(tp, user, file, offset)
251	register FILE *tp;
252	char user[];
253	char file[];
254	off_t offset;
255{
256	register unsigned char *cp, ch;
257	register FILE *fi;
258	register int linecnt, charcnt, inheader;
259	register struct passwd *p;
260	unsigned char line[BUFSIZ];
261
262	/* Set effective uid to user in case mail drop is on nfs */
263	if ((p = getpwnam(user)) != NULL)
264		(void) setuid(p->pw_uid);
265
266	if ((fi = fopen(file, "r")) == NULL)
267		return;
268
269	(void)fseek(fi, offset, L_SET);
270	/*
271	 * Print the first 7 lines or 560 characters of the new mail
272	 * (whichever comes first).  Skip header crap other than
273	 * From, Subject, To, and Date.
274	 */
275	linecnt = 7;
276	charcnt = 560;
277	inheader = 1;
278	while (fgets(line, sizeof(line), fi) != NULL) {
279		if (inheader) {
280			if (line[0] == '\n') {
281				inheader = 0;
282				continue;
283			}
284			if (line[0] == ' ' || line[0] == '\t' ||
285			    (strncmp(line, "From:", 5) &&
286			    strncmp(line, "Subject:", 8)))
287				continue;
288		}
289		if (linecnt <= 0 || charcnt <= 0) {
290			(void)fprintf(tp, "...more...%s", cr);
291			(void)fclose(fi);
292			return;
293		}
294		/* strip weird stuff so can't trojan horse stupid terminals */
295		for (cp = line; (ch = *cp) && ch != '\n'; ++cp, --charcnt) {
296			/* disable upper controls and enable all other
297			   8bit codes due to lack of locale knowledge
298			 */
299			if (((ch & 0x80) && ch < 0xA0) ||
300			    (!(ch & 0x80) && !isprint(ch) &&
301			     !isspace(ch) && ch != '\a' && ch != '\b')
302			   ) {
303				if (ch & 0x80) {
304					ch &= ~0x80;
305					(void)fputs("M-", tp);
306				}
307				if (iscntrl(ch)) {
308					ch ^= 0x40;
309					(void)fputc('^', tp);
310				}
311			}
312			(void)fputc(ch, tp);
313		}
314		(void)fputs(cr, tp);
315		--linecnt;
316	}
317	(void)fprintf(tp, "----%s\n", cr);
318	(void)fclose(fi);
319}
320