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