1 /* $NetBSD: comsat.c,v 1.23 2002/03/18 23:34:21 mjl Exp $ */ 2 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. 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 #ifndef lint 38 __COPYRIGHT("@(#) Copyright (c) 1980, 1993\n\ 39 The Regents of the University of California. All rights reserved.\n"); 40 #if 0 41 static char sccsid[] = "from: @(#)comsat.c 8.1 (Berkeley) 6/4/93"; 42 #else 43 __RCSID("$NetBSD: comsat.c,v 1.23 2002/03/18 23:34:21 mjl Exp $"); 44 #endif 45 #endif /* not lint */ 46 47 #include <sys/param.h> 48 #include <sys/socket.h> 49 #include <sys/stat.h> 50 #include <sys/file.h> 51 #include <sys/wait.h> 52 53 #include <netinet/in.h> 54 55 #include <ctype.h> 56 #include <errno.h> 57 #include <netdb.h> 58 #include <paths.h> 59 #include <pwd.h> 60 #include <signal.h> 61 #include <stdio.h> 62 #include <stdlib.h> 63 #include <string.h> 64 #include <syslog.h> 65 #include <termios.h> 66 #include <time.h> 67 #include <vis.h> 68 #include <unistd.h> 69 #include <utmp.h> 70 71 int logging; 72 int debug = 0; 73 #define dsyslog if (debug) syslog 74 75 #define MAXIDLE 120 76 77 char hostname[MAXHOSTNAMELEN+1]; 78 struct utmp *utmp = NULL; 79 time_t lastmsgtime; 80 int nutmp, uf; 81 82 void jkfprintf (FILE *, char[], off_t); 83 void mailfor (char *); 84 void notify (struct utmp *, off_t); 85 void onalrm (int); 86 void reapchildren (int); 87 88 int 89 main(int argc, char *argv[]) 90 { 91 struct sockaddr_storage from; 92 int cc, ch; 93 int fromlen; 94 char msgbuf[100]; 95 sigset_t sigset; 96 97 /* verify proper invocation */ 98 fromlen = sizeof(from); 99 if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0) { 100 (void)fprintf(stderr, 101 "comsat: getsockname: %s.\n", strerror(errno)); 102 exit(1); 103 } 104 105 openlog("comsat", LOG_PID, LOG_DAEMON); 106 while ((ch = getopt(argc, argv, "l")) != -1) 107 switch (ch) { 108 case 'l': 109 logging = 1; 110 break; 111 default: 112 syslog(LOG_ERR, "Usage: %s [-l]", getprogname()); 113 exit(1); 114 } 115 if (chdir(_PATH_MAILDIR)) { 116 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR); 117 (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 118 exit(1); 119 } 120 if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) { 121 syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP); 122 (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 123 exit(1); 124 } 125 (void)time(&lastmsgtime); 126 (void)gethostname(hostname, sizeof(hostname)); 127 hostname[sizeof(hostname) - 1] = '\0'; 128 onalrm(0); 129 (void)signal(SIGALRM, onalrm); 130 (void)signal(SIGTTOU, SIG_IGN); 131 (void)signal(SIGCHLD, reapchildren); 132 for (;;) { 133 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 134 if (cc <= 0) { 135 if (errno != EINTR) 136 sleep(1); 137 errno = 0; 138 continue; 139 } 140 if (!nutmp) /* no one has logged in yet */ 141 continue; 142 sigemptyset(&sigset); 143 sigaddset(&sigset, SIGALRM); 144 sigprocmask(SIG_SETMASK, &sigset, NULL); 145 msgbuf[cc] = '\0'; 146 (void)time(&lastmsgtime); 147 mailfor(msgbuf); 148 sigemptyset(&sigset); 149 sigprocmask(SIG_SETMASK, &sigset, NULL); 150 } 151 } 152 153 void 154 reapchildren(int signo) 155 { 156 157 while (wait3(NULL, WNOHANG, NULL) > 0); 158 } 159 160 void 161 onalrm(int signo) 162 { 163 static u_int utmpsize; /* last malloced size for utmp */ 164 static u_int utmpmtime; /* last modification time for utmp */ 165 struct stat statbf; 166 167 if (time(NULL) - lastmsgtime >= MAXIDLE) 168 exit(0); 169 (void)alarm((u_int)15); 170 (void)fstat(uf, &statbf); 171 if (statbf.st_mtime > utmpmtime) { 172 utmpmtime = statbf.st_mtime; 173 if (statbf.st_size > utmpsize) { 174 utmpsize = statbf.st_size + 10 * sizeof(struct utmp); 175 if ((utmp = realloc(utmp, utmpsize)) == NULL) { 176 syslog(LOG_ERR, "%s", strerror(errno)); 177 exit(1); 178 } 179 } 180 (void)lseek(uf, (off_t)0, SEEK_SET); 181 nutmp = read(uf, utmp, (int)statbf.st_size)/sizeof(struct utmp); 182 } 183 } 184 185 void 186 mailfor(char *name) 187 { 188 struct utmp *utp = &utmp[nutmp]; 189 char *cp, *fn; 190 off_t offset; 191 192 if (!(cp = strchr(name, '@'))) 193 return; 194 *cp = '\0'; 195 errno = 0; 196 offset = strtol(cp + 1, &fn, 10); 197 if (errno == ERANGE) 198 return; 199 if (fn && *fn && *fn != '\n') { 200 /* 201 * Procmail sends messages to comsat with a trailing colon 202 * and a pathname to the folder where the new message was 203 * deposited. Since we can't reliably open only regular 204 * files, we need to ignore these. With one exception: 205 * if it mentions the user's system mailbox. 206 */ 207 char maildir[128]; 208 int l = snprintf(maildir, sizeof(maildir), ":%s/%s", 209 _PATH_MAILDIR, name); 210 if (l > sizeof(maildir) || strcmp(maildir, fn) != 0) 211 return; 212 } 213 while (--utp >= utmp) 214 if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name))) 215 notify(utp, offset); 216 } 217 218 static char *cr; 219 220 void 221 notify(struct utmp *utp, off_t offset) 222 { 223 FILE *tp; 224 struct passwd *p; 225 struct stat stb; 226 struct termios ttybuf; 227 char tty[20], name[sizeof(utmp[0].ut_name) + 1]; 228 229 (void)snprintf(tty, sizeof(tty), "%s%.*s", 230 _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line); 231 if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) { 232 /* A slash is an attempt to break security... */ 233 /* 234 * XXX but what about something like "/dev/pts/5" 235 * that we may one day "support". ? 236 */ 237 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty); 238 return; 239 } 240 if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) { 241 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty); 242 return; 243 } 244 dsyslog(LOG_DEBUG, "notify %s on %s", utp->ut_name, tty); 245 if (fork()) 246 return; 247 (void)signal(SIGALRM, SIG_DFL); 248 (void)alarm((u_int)30); 249 if ((tp = fopen(tty, "w")) == NULL) { 250 dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno)); 251 _exit(1); 252 } 253 (void)tcgetattr(fileno(tp), &ttybuf); 254 cr = (ttybuf.c_oflag & ONLCR) && (ttybuf.c_oflag & OPOST) ? 255 "\n" : "\n\r"; 256 (void)strlcpy(name, utp->ut_name, sizeof(name)); 257 258 /* Set uid/gid/groups to users in case mail drop is on nfs */ 259 if ((p = getpwnam(name)) == NULL || 260 initgroups(p->pw_name, p->pw_gid) < 0 || 261 setgid(p->pw_gid) < 0 || 262 setuid(p->pw_uid) < 0) 263 _exit(1); 264 265 if (logging) 266 syslog(LOG_INFO, "biff message for %s", name); 267 268 (void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s", 269 cr, name, (int)sizeof(hostname), hostname, cr, cr); 270 jkfprintf(tp, name, offset); 271 (void)fclose(tp); 272 _exit(0); 273 } 274 275 void 276 jkfprintf(FILE *tp, char name[], off_t offset) 277 { 278 FILE *fi; 279 int linecnt, charcnt, inheader; 280 char line[BUFSIZ], visline[BUFSIZ*4], *nl; 281 282 if ((fi = fopen(name, "r")) == NULL) 283 return; 284 285 (void)fseek(fi, offset, SEEK_SET); 286 /* 287 * Print the first 7 lines or 560 characters of the new mail 288 * (whichever comes first). Skip header crap other than 289 * From, Subject, To, and Date. 290 */ 291 linecnt = 7; 292 charcnt = 560; 293 inheader = 1; 294 while (fgets(line, sizeof(line), fi) != NULL) { 295 line[sizeof(line) - 1] = '\0'; 296 if (inheader) { 297 if (line[0] == '\n') { 298 inheader = 0; 299 continue; 300 } 301 if (line[0] == ' ' || line[0] == '\t' || 302 (strncasecmp(line, "From:", 5) && 303 strncasecmp(line, "Subject:", 8))) 304 continue; 305 } 306 if (strncmp(line, "From ", 5) == 0) { 307 (void)fprintf(tp, "----%s", cr); 308 (void)fclose(fi); 309 return; 310 } 311 if (linecnt <= 0 || charcnt <= 0) { 312 (void)fprintf(tp, "...more...%s", cr); 313 (void)fclose(fi); 314 return; 315 } 316 if ((nl = strchr(line, '\n')) != NULL) 317 *nl = '\0'; 318 /* strip weird stuff so can't trojan horse stupid terminals */ 319 (void)strvis(visline, line, VIS_CSTYLE); 320 (void)fputs(visline, tp); 321 (void)fputs(cr, tp); 322 --linecnt; 323 } 324 (void)fprintf(tp, "----%s\n", cr); 325 (void)fclose(fi); 326 } 327