comsat.c revision 1.28
1 /* $NetBSD: comsat.c,v 1.28 2004/07/10 00:00:58 enami 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 1.28 2004/07/10 00:00:58 enami 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 = 0; 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 91 int main(int, char *[]); 92 static void jkfprintf(FILE *, const char *, off_t, const char *); 93 static void mailfor(const char *); 94 static void notify(const struct utmpentry *, off_t); 95 static void onalrm(int); 96 static void reapchildren(int); 97 98 int 99 main(int argc, char *argv[]) 100 { 101 struct sockaddr_storage from; 102 int cc, ch; 103 socklen_t fromlen; 104 char msgbuf[100]; 105 sigset_t nsigset, osigset; 106 107 /* verify proper invocation */ 108 fromlen = sizeof(from); 109 if (getsockname(0, (struct sockaddr *)(void *)&from, &fromlen) == -1) 110 err(1, "getsockname"); 111 112 openlog("comsat", LOG_PID, LOG_DAEMON); 113 while ((ch = getopt(argc, argv, "l")) != -1) 114 switch (ch) { 115 case 'l': 116 logging = 1; 117 break; 118 default: 119 syslog(LOG_ERR, "Usage: %s [-l]", getprogname()); 120 exit(1); 121 } 122 if (chdir(_PATH_MAILDIR) == -1) { 123 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR); 124 (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 125 exit(1); 126 } 127 (void)time(&lastmsgtime); 128 (void)gethostname(hostname, sizeof(hostname)); 129 hostname[sizeof(hostname) - 1] = '\0'; 130 onalrm(0); 131 (void)signal(SIGALRM, onalrm); 132 (void)signal(SIGTTOU, SIG_IGN); 133 (void)signal(SIGCHLD, reapchildren); 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 for (;;) { 141 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 142 if (cc <= 0) { 143 if (errno != EINTR) 144 sleep(1); 145 errno = 0; 146 continue; 147 } 148 if (!nutmp) /* no one has logged in yet */ 149 continue; 150 if (sigprocmask(SIG_SETMASK, &nsigset, NULL) == -1) { 151 syslog(LOG_ERR, "sigprocmask set failed (%m)"); 152 exit(1); 153 } 154 msgbuf[cc] = '\0'; 155 (void)time(&lastmsgtime); 156 mailfor(msgbuf); 157 if (sigprocmask(SIG_SETMASK, &osigset, NULL) == -1) { 158 syslog(LOG_ERR, "sigprocmask restore failed (%m)"); 159 exit(1); 160 } 161 } 162 } 163 164 static void 165 /*ARGSUSED*/ 166 reapchildren(int signo) 167 { 168 169 while (wait3(NULL, WNOHANG, NULL) != -1) 170 continue; 171 } 172 173 static void 174 /*ARGSUSED*/ 175 onalrm(int signo) 176 { 177 struct stat statbf; 178 time_t newtime = 0; 179 180 if (time(NULL) - lastmsgtime >= MAXIDLE) 181 exit(0); 182 (void)alarm((u_int)15); 183 #ifdef SUPPORT_UTMP 184 if (stat(_PATH_UTMP, &statbf) != -1) 185 if (statbf.st_mtime > newtime) 186 newtime = statbf.st_mtime; 187 #endif 188 #ifdef SUPPORT_UTMPX 189 if (stat(_PATH_UTMP, &statbf) != -1) 190 if (statbf.st_mtime > newtime) 191 newtime = statbf.st_mtime; 192 #endif 193 if (newtime > utmpmtime) { 194 freeutentries(utmp); 195 nutmp = getutentries(NULL, &utmp); 196 utmpmtime = newtime; 197 } 198 } 199 200 static void 201 mailfor(const char *name) 202 { 203 struct utmpentry *ep; 204 char *cp, *fn; 205 off_t offset; 206 207 if (!(cp = strchr(name, '@'))) 208 return; 209 *cp = '\0'; 210 errno = 0; 211 offset = strtol(cp + 1, &fn, 10); 212 if (errno == ERANGE && (offset == LONG_MAX || offset == LONG_MIN)) 213 return; 214 if (fn && *fn && *fn != '\n') { 215 /* 216 * Procmail sends messages to comsat with a trailing colon 217 * and a pathname to the folder where the new message was 218 * deposited. Since we can't reliably open only regular 219 * files, we need to ignore these. With one exception: 220 * if it mentions the user's system mailbox. 221 */ 222 char maildir[MAXPATHLEN]; 223 int l = snprintf(maildir, sizeof(maildir), ":%s/%s", 224 _PATH_MAILDIR, name); 225 if (l > sizeof(maildir) || strcmp(maildir, fn) != 0) 226 return; 227 } 228 for (ep = utmp; ep != NULL; ep = ep->next) 229 if (strcmp(ep->name, name) == 0) 230 notify(ep, offset); 231 } 232 233 static void 234 notify(const struct utmpentry *ep, off_t offset) 235 { 236 FILE *tp; 237 struct passwd *p; 238 struct stat stb; 239 struct termios ttybuf; 240 char tty[sizeof(_PATH_DEV) + sizeof(ep->line) + 1]; 241 const char *cr; 242 243 (void)snprintf(tty, sizeof(tty), "%s%s", _PATH_DEV, ep->line); 244 if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) { 245 /* A slash is an attempt to break security... */ 246 /* 247 * XXX but what about something like "/dev/pts/5" 248 * that we may one day "support". ? 249 */ 250 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty); 251 return; 252 } 253 if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) { 254 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", ep->name, tty); 255 return; 256 } 257 dsyslog(LOG_DEBUG, "notify %s on %s", ep->name, tty); 258 if (fork()) 259 return; 260 (void)signal(SIGALRM, SIG_DFL); 261 (void)alarm((u_int)30); 262 if ((tp = fopen(tty, "w")) == NULL) { 263 dsyslog(LOG_ERR, "open `%s' (%s)", tty, strerror(errno)); 264 _exit(1); 265 } 266 if (tcgetattr(fileno(tp), &ttybuf) == -1) { 267 dsyslog(LOG_ERR, "tcgetattr `%s' (%s)", tty, strerror(errno)); 268 _exit(1); 269 } 270 cr = (ttybuf.c_oflag & ONLCR) && (ttybuf.c_oflag & OPOST) ? 271 "\n" : "\n\r"; 272 /* Set uid/gid/groups to users in case mail drop is on nfs */ 273 if ((p = getpwnam(ep->name)) == NULL || 274 initgroups(p->pw_name, p->pw_gid) == -1 || 275 setgid(p->pw_gid) == -1 || 276 setuid(p->pw_uid) == -1) 277 _exit(1); 278 279 if (logging) 280 syslog(LOG_INFO, "biff message for %s", ep->name); 281 282 (void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s", 283 cr, ep->name, (int)sizeof(hostname), hostname, cr, cr); 284 jkfprintf(tp, ep->name, offset, cr); 285 (void)fclose(tp); 286 _exit(0); 287 } 288 289 static void 290 jkfprintf(FILE *tp, const char *name, off_t offset, const char *cr) 291 { 292 FILE *fi; 293 int linecnt, charcnt, inheader; 294 char line[BUFSIZ], visline[BUFSIZ * 4 + 1], *nl; 295 296 if ((fi = fopen(name, "r")) == NULL) 297 return; 298 299 (void)fseeko(fi, offset, SEEK_SET); 300 /* 301 * Print the first 7 lines or 560 characters of the new mail 302 * (whichever comes first). Skip header crap other than 303 * From, Subject, To, and Date. 304 */ 305 linecnt = 7; 306 charcnt = 560; 307 inheader = 1; 308 while (fgets(line, sizeof(line), fi) != NULL) { 309 line[sizeof(line) - 1] = '\0'; 310 if (inheader) { 311 if (line[0] == '\n') { 312 inheader = 0; 313 continue; 314 } 315 if (line[0] == ' ' || line[0] == '\t' || 316 (strncasecmp(line, "From:", 5) && 317 strncasecmp(line, "Subject:", 8))) 318 continue; 319 } 320 if (strncmp(line, "From ", 5) == 0) { 321 (void)fprintf(tp, "----%s", cr); 322 (void)fclose(fi); 323 return; 324 } 325 if (linecnt <= 0 || charcnt <= 0) { 326 (void)fprintf(tp, "...more...%s", cr); 327 (void)fclose(fi); 328 return; 329 } 330 if ((nl = strchr(line, '\n')) != NULL) 331 *nl = '\0'; 332 /* strip weird stuff so can't trojan horse stupid terminals */ 333 (void)strvis(visline, line, VIS_CSTYLE); 334 (void)fputs(visline, tp); 335 (void)fputs(cr, tp); 336 --linecnt; 337 } 338 (void)fprintf(tp, "----%s\n", cr); 339 (void)fclose(fi); 340 } 341
Indexes created Tue Sep 23 14:10:03 GMT 2025