comsat.c revision 1.34
1 /* $NetBSD: comsat.c,v 1.34 2005/07/18 04:01:33 christos 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. 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 #include <sys/cdefs.h> 33 #ifndef lint 34 __COPYRIGHT("@(#) Copyright (c) 1980, 1993\n\ 35 The Regents of the University of California. All rights reserved.\n"); 36 #if 0 37 static char sccsid[] = "from: @(#)comsat.c 8.1 (Berkeley) 6/4/93"; 38 #else 39 __RCSID("$NetBSD: comsat.c,v 1.34 2005/07/18 04:01:33 christos Exp $"); 40 #endif 41 #endif /* not lint */ 42 43 #include <sys/param.h> 44 #include <sys/socket.h> 45 #include <sys/stat.h> 46 #include <sys/file.h> 47 #include <sys/wait.h> 48 49 #include <netinet/in.h> 50 51 #include <ctype.h> 52 #include <errno.h> 53 #include <netdb.h> 54 #include <paths.h> 55 #include <pwd.h> 56 #include <err.h> 57 #include <signal.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <syslog.h> 62 #include <termios.h> 63 #include <time.h> 64 #include <vis.h> 65 #include <unistd.h> 66 #ifdef SUPPORT_UTMP 67 #include <utmp.h> 68 #endif 69 #ifdef SUPPORT_UTMPX 70 #include <utmpx.h> 71 #endif 72 73 #include "utmpentry.h" 74 75 #if !defined(SUPPORT_UTMP) && !defined(SUPPORT_UTMPX) 76 #error "SUPPORT_UTMP and/or SUPPORT_UTMPX must be defined" 77 #endif 78 79 #define dsyslog if (debug) syslog 80 81 #define MAXIDLE 120 82 83 static int logging; 84 static int debug; 85 static char hostname[MAXHOSTNAMELEN + 1]; 86 static time_t utmpmtime; /* last modification time for utmp/x */ 87 static int nutmp; 88 static struct utmpentry *utmp = NULL; 89 static time_t lastmsgtime; 90 static volatile sig_atomic_t needupdate; 91 92 int main(int, char *[]); 93 static void jkfprintf(FILE *, const char *, off_t, const char *); 94 static void mailfor(const char *); 95 static void notify(const struct utmpentry *, off_t); 96 static void onalrm(int); 97 static void checkutmp(void); 98 99 int 100 main(int argc, char *argv[]) 101 { 102 struct sockaddr_storage from; 103 int cc, ch; 104 socklen_t fromlen; 105 char msgbuf[100]; 106 sigset_t nsigset, osigset; 107 108 /* verify proper invocation */ 109 fromlen = sizeof(from); 110 if (getsockname(0, (struct sockaddr *)(void *)&from, &fromlen) == -1) 111 err(1, "getsockname"); 112 113 openlog("comsat", LOG_PID, LOG_DAEMON); 114 while ((ch = getopt(argc, argv, "l")) != -1) 115 switch (ch) { 116 case 'l': 117 logging = 1; 118 break; 119 default: 120 syslog(LOG_ERR, "Usage: %s [-l]", getprogname()); 121 exit(1); 122 } 123 if (chdir(_PATH_MAILDIR) == -1) { 124 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR); 125 (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 126 exit(1); 127 } 128 (void)time(&lastmsgtime); 129 (void)gethostname(hostname, sizeof(hostname)); 130 hostname[sizeof(hostname) - 1] = '\0'; 131 (void)signal(SIGALRM, onalrm); 132 (void)signal(SIGTTOU, SIG_IGN); 133 (void)signal(SIGCHLD, SIG_IGN); 134 (void)sigemptyset(&nsigset); 135 (void)sigaddset(&nsigset, SIGALRM); 136 if (sigprocmask(SIG_SETMASK, NULL, &osigset) == -1) { 137 syslog(LOG_ERR, "sigprocmask get failed (%m)"); 138 exit(1); 139 } 140 needupdate++; 141 for (;;) { 142 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 143 if (cc <= 0) { 144 if (errno != EINTR) 145 sleep(1); 146 errno = 0; 147 checkutmp(); 148 continue; 149 } else 150 checkutmp(); 151 if (!nutmp) /* no one has logged in yet */ 152 continue; 153 if (sigprocmask(SIG_SETMASK, &nsigset, NULL) == -1) { 154 syslog(LOG_ERR, "sigprocmask set failed (%m)"); 155 exit(1); 156 } 157 msgbuf[cc] = '\0'; 158 (void)time(&lastmsgtime); 159 mailfor(msgbuf); 160 if (sigprocmask(SIG_SETMASK, &osigset, NULL) == -1) { 161 syslog(LOG_ERR, "sigprocmask restore failed (%m)"); 162 exit(1); 163 } 164 } 165 } 166 167 static void 168 /*ARGSUSED*/ 169 onalrm(int signo) 170 { 171 needupdate++; 172 } 173 174 static void 175 checkutmp(void) 176 { 177 struct stat statbf; 178 time_t newtime = 0; 179 180 if (!needupdate) 181 return; 182 needupdate = 0; 183 184 if (time(NULL) - lastmsgtime >= MAXIDLE) 185 exit(0); 186 (void)alarm((u_int)15); 187 #ifdef SUPPORT_UTMP 188 if (stat(_PATH_UTMP, &statbf) != -1) 189 if (statbf.st_mtime > newtime) 190 newtime = statbf.st_mtime; 191 #endif 192 #ifdef SUPPORT_UTMPX 193 if (stat(_PATH_UTMPX, &statbf) != -1) 194 if (statbf.st_mtime > newtime) 195 newtime = statbf.st_mtime; 196 #endif 197 if (newtime > utmpmtime) { 198 freeutentries(utmp); 199 nutmp = getutentries(NULL, &utmp); 200 utmpmtime = newtime; 201 } 202 } 203 204 static void 205 mailfor(const char *name) 206 { 207 struct utmpentry *ep; 208 char *cp, *fn; 209 off_t offset; 210 intmax_t val; 211 212 if (!(cp = strchr(name, '@'))) 213 return; 214 *cp = '\0'; 215 errno = 0; 216 offset = val = strtoimax(cp + 1, &fn, 10); 217 if (errno == ERANGE || offset != val) 218 return; 219 if (fn && *fn && *fn != '\n') { 220 /* 221 * Procmail sends messages to comsat with a trailing colon 222 * and a pathname to the folder where the new message was 223 * deposited. Since we can't reliably open only regular 224 * files, we need to ignore these. With one exception: 225 * if it mentions the user's system mailbox. 226 */ 227 char maildir[MAXPATHLEN]; 228 int l = snprintf(maildir, sizeof(maildir), ":%s/%s", 229 _PATH_MAILDIR, name); 230 if (l >= sizeof(maildir) || strcmp(maildir, fn) != 0) 231 return; 232 } 233 for (ep = utmp; ep != NULL; ep = ep->next) 234 if (strcmp(ep->name, name) == 0) 235 notify(ep, offset); 236 } 237 238 static void 239 notify(const struct utmpentry *ep, off_t offset) 240 { 241 FILE *tp; 242 struct passwd *p; 243 struct stat stb; 244 struct termios ttybuf; 245 char tty[sizeof(_PATH_DEV) + sizeof(ep->line) + 1]; 246 const char *cr = ep->line; 247 248 if (strncmp(cr, "pts/", 4) == 0) 249 cr += 4; 250 if (strchr(cr, '/')) { 251 /* A slash is an attempt to break security... */ 252 syslog(LOG_AUTH | LOG_NOTICE, "Unexpected `/' in `%s'", 253 ep->line); 254 return; 255 } 256 (void)snprintf(tty, sizeof(tty), "%s%s", _PATH_DEV, ep->line); 257 if (stat(tty, &stb) == -1 || !(stb.st_mode & S_IEXEC)) { 258 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", ep->name, tty); 259 return; 260 } 261 dsyslog(LOG_DEBUG, "notify %s on %s", ep->name, tty); 262 switch (fork()) { 263 case -1: 264 syslog(LOG_NOTICE, "fork failed (%m)"); 265 return; 266 case 0: 267 break; 268 default: 269 return; 270 } 271 (void)signal(SIGALRM, SIG_DFL); 272 (void)alarm((u_int)30); 273 if ((tp = fopen(tty, "w")) == NULL) { 274 dsyslog(LOG_ERR, "open `%s' (%s)", tty, strerror(errno)); 275 _exit(1); 276 } 277 if (tcgetattr(fileno(tp), &ttybuf) == -1) { 278 dsyslog(LOG_ERR, "tcgetattr `%s' (%s)", tty, strerror(errno)); 279 _exit(1); 280 } 281 cr = (ttybuf.c_oflag & ONLCR) && (ttybuf.c_oflag & OPOST) ? 282 "\n" : "\n\r"; 283 /* Set uid/gid/groups to users in case mail drop is on nfs */ 284 if ((p = getpwnam(ep->name)) == NULL || 285 initgroups(p->pw_name, p->pw_gid) == -1 || 286 setgid(p->pw_gid) == -1 || 287 setuid(p->pw_uid) == -1) 288 _exit(1); 289 290 if (logging) 291 syslog(LOG_INFO, "biff message for %s", ep->name); 292 293 (void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s", 294 cr, ep->name, (int)sizeof(hostname), hostname, cr, cr); 295 jkfprintf(tp, ep->name, offset, cr); 296 (void)fclose(tp); 297 _exit(0); 298 } 299 300 static void 301 jkfprintf(FILE *tp, const char *name, off_t offset, const char *cr) 302 { 303 FILE *fi; 304 int linecnt, charcnt, inheader; 305 char line[BUFSIZ], visline[BUFSIZ * 4 + 1], *nl; 306 307 if ((fi = fopen(name, "r")) == NULL) 308 return; 309 310 (void)fseeko(fi, offset, SEEK_SET); 311 /* 312 * Print the first 7 lines or 560 characters of the new mail 313 * (whichever comes first). Skip header crap other than 314 * From, Subject, To, and Date. 315 */ 316 linecnt = 7; 317 charcnt = 560; 318 inheader = 1; 319 while (fgets(line, sizeof(line), fi) != NULL) { 320 line[sizeof(line) - 1] = '\0'; 321 if (inheader) { 322 if (line[0] == '\n') { 323 inheader = 0; 324 continue; 325 } 326 if (line[0] == ' ' || line[0] == '\t' || 327 (strncasecmp(line, "From:", 5) && 328 strncasecmp(line, "Subject:", 8))) 329 continue; 330 } 331 if (strncmp(line, "From ", 5) == 0) { 332 (void)fprintf(tp, "----%s", cr); 333 (void)fclose(fi); 334 return; 335 } 336 if (linecnt <= 0 || charcnt <= 0) { 337 (void)fprintf(tp, "...more...%s", cr); 338 (void)fclose(fi); 339 return; 340 } 341 if ((nl = strchr(line, '\n')) != NULL) 342 *nl = '\0'; 343 /* strip weird stuff so can't trojan horse stupid terminals */ 344 (void)strvis(visline, line, VIS_CSTYLE); 345 (void)fputs(visline, tp); 346 (void)fputs(cr, tp); 347 --linecnt; 348 } 349 (void)fprintf(tp, "----%s\n", cr); 350 (void)fclose(fi); 351 } 352
Indexes created Fri Sep 26 08:10:20 GMT 2025