1 /*
2 * Copyright (c) 1980, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * %sccs.include.redist.c%
6 */
7
8 #ifndef lint
9 static char copyright[] =
10 "@(#) Copyright (c) 1980, 1993\n\
11 The Regents of the University of California. All rights reserved.\n";
12 #endif /* not lint */
13
14 #ifndef lint
15 static char sccsid[] = "@(#)comsat.c 8.1 (Berkeley) 06/04/93";
16 #endif /* not lint */
17
18 #include <sys/param.h>
19 #include <sys/socket.h>
20 #include <sys/stat.h>
21 #include <sys/file.h>
22 #include <sys/wait.h>
23
24 #include <netinet/in.h>
25
26 #include <ctype.h>
27 #include <errno.h>
28 #include <netdb.h>
29 #include <paths.h>
30 #include <pwd.h>
31 #include <sgtty.h>
32 #include <signal.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
36 #include <syslog.h>
37 #include <unistd.h>
38 #include <utmp.h>
39
40 int debug = 0;
41 #define dsyslog if (debug) syslog
42
43 #define MAXIDLE 120
44
45 char hostname[MAXHOSTNAMELEN];
46 struct utmp *utmp = NULL;
47 time_t lastmsgtime;
48 int nutmp, uf;
49
50 void jkfprintf __P((FILE *, char[], off_t));
51 void mailfor __P((char *));
52 void notify __P((struct utmp *, off_t));
53 void onalrm __P((int));
54 void reapchildren __P((int));
55
56 int
main(argc,argv)57 main(argc, argv)
58 int argc;
59 char *argv[];
60 {
61 struct sockaddr_in from;
62 register int cc;
63 int fromlen;
64 char msgbuf[100];
65
66 /* verify proper invocation */
67 fromlen = sizeof(from);
68 if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0) {
69 (void)fprintf(stderr,
70 "comsat: getsockname: %s.\n", strerror(errno));
71 exit(1);
72 }
73 openlog("comsat", LOG_PID, LOG_DAEMON);
74 if (chdir(_PATH_MAILDIR)) {
75 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR);
76 (void) recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
77 exit(1);
78 }
79 if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) {
80 syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP);
81 (void) recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
82 exit(1);
83 }
84 (void)time(&lastmsgtime);
85 (void)gethostname(hostname, sizeof(hostname));
86 onalrm(0);
87 (void)signal(SIGALRM, onalrm);
88 (void)signal(SIGTTOU, SIG_IGN);
89 (void)signal(SIGCHLD, reapchildren);
90 for (;;) {
91 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
92 if (cc <= 0) {
93 if (errno != EINTR)
94 sleep(1);
95 errno = 0;
96 continue;
97 }
98 if (!nutmp) /* no one has logged in yet */
99 continue;
100 sigblock(sigmask(SIGALRM));
101 msgbuf[cc] = '\0';
102 (void)time(&lastmsgtime);
103 mailfor(msgbuf);
104 sigsetmask(0L);
105 }
106 }
107
108 void
reapchildren(signo)109 reapchildren(signo)
110 int signo;
111 {
112 while (wait3(NULL, WNOHANG, NULL) > 0);
113 }
114
115 void
onalrm(signo)116 onalrm(signo)
117 int signo;
118 {
119 static u_int utmpsize; /* last malloced size for utmp */
120 static u_int utmpmtime; /* last modification time for utmp */
121 struct stat statbf;
122
123 if (time(NULL) - lastmsgtime >= MAXIDLE)
124 exit(0);
125 (void)alarm((u_int)15);
126 (void)fstat(uf, &statbf);
127 if (statbf.st_mtime > utmpmtime) {
128 utmpmtime = statbf.st_mtime;
129 if (statbf.st_size > utmpsize) {
130 utmpsize = statbf.st_size + 10 * sizeof(struct utmp);
131 if ((utmp = realloc(utmp, utmpsize)) == NULL) {
132 syslog(LOG_ERR, "%s", strerror(errno));
133 exit(1);
134 }
135 }
136 (void)lseek(uf, (off_t)0, L_SET);
137 nutmp = read(uf, utmp, (int)statbf.st_size)/sizeof(struct utmp);
138 }
139 }
140
141 void
mailfor(name)142 mailfor(name)
143 char *name;
144 {
145 register struct utmp *utp = &utmp[nutmp];
146 register char *cp;
147 off_t offset;
148
149 if (!(cp = strchr(name, '@')))
150 return;
151 *cp = '\0';
152 offset = atoi(cp + 1);
153 while (--utp >= utmp)
154 if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name)))
155 notify(utp, offset);
156 }
157
158 static char *cr;
159
160 void
notify(utp,offset)161 notify(utp, offset)
162 register struct utmp *utp;
163 off_t offset;
164 {
165 FILE *tp;
166 struct stat stb;
167 struct sgttyb gttybuf;
168 char tty[20], name[sizeof(utmp[0].ut_name) + 1];
169
170 (void)snprintf(tty, sizeof(tty), "%s%.*s",
171 _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line);
172 if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) {
173 /* A slash is an attempt to break security... */
174 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty);
175 return;
176 }
177 if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) {
178 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty);
179 return;
180 }
181 dsyslog(LOG_DEBUG, "notify %s on %s\n", utp->ut_name, tty);
182 if (fork())
183 return;
184 (void)signal(SIGALRM, SIG_DFL);
185 (void)alarm((u_int)30);
186 if ((tp = fopen(tty, "w")) == NULL) {
187 dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno));
188 _exit(-1);
189 }
190 (void)ioctl(fileno(tp), TIOCGETP, >tybuf);
191 cr = (gttybuf.sg_flags&CRMOD) && !(gttybuf.sg_flags&RAW) ?
192 "\n" : "\n\r";
193 (void)strncpy(name, utp->ut_name, sizeof(utp->ut_name));
194 name[sizeof(name) - 1] = '\0';
195 (void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s",
196 cr, name, (int)sizeof(hostname), hostname, cr, cr);
197 jkfprintf(tp, name, offset);
198 (void)fclose(tp);
199 _exit(0);
200 }
201
202 void
jkfprintf(tp,name,offset)203 jkfprintf(tp, name, offset)
204 register FILE *tp;
205 char name[];
206 off_t offset;
207 {
208 register char *cp, ch;
209 register FILE *fi;
210 register int linecnt, charcnt, inheader;
211 register struct passwd *p;
212 char line[BUFSIZ];
213
214 /* Set effective uid to user in case mail drop is on nfs */
215 if ((p = getpwnam(name)) != NULL)
216 (void) setuid(p->pw_uid);
217
218 if ((fi = fopen(name, "r")) == NULL)
219 return;
220
221 (void)fseek(fi, offset, L_SET);
222 /*
223 * Print the first 7 lines or 560 characters of the new mail
224 * (whichever comes first). Skip header crap other than
225 * From, Subject, To, and Date.
226 */
227 linecnt = 7;
228 charcnt = 560;
229 inheader = 1;
230 while (fgets(line, sizeof(line), fi) != NULL) {
231 if (inheader) {
232 if (line[0] == '\n') {
233 inheader = 0;
234 continue;
235 }
236 if (line[0] == ' ' || line[0] == '\t' ||
237 strncmp(line, "From:", 5) &&
238 strncmp(line, "Subject:", 8))
239 continue;
240 }
241 if (linecnt <= 0 || charcnt <= 0) {
242 (void)fprintf(tp, "...more...%s", cr);
243 (void)fclose(fi);
244 return;
245 }
246 /* strip weird stuff so can't trojan horse stupid terminals */
247 for (cp = line; (ch = *cp) && ch != '\n'; ++cp, --charcnt) {
248 ch = toascii(ch);
249 if (!isprint(ch) && !isspace(ch))
250 ch |= 0x40;
251 (void)fputc(ch, tp);
252 }
253 (void)fputs(cr, tp);
254 --linecnt;
255 }
256 (void)fprintf(tp, "----%s\n", cr);
257 (void)fclose(fi);
258 }
259