comsat.c revision 1.25
1 /* $NetBSD: comsat.c,v 1.25 2003/08/07 09:46:37 agc 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 1.25 2003/08/07 09:46:37 agc 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 <signal.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 #include <syslog.h> 61 #include <termios.h> 62 #include <time.h> 63 #include <vis.h> 64 #include <unistd.h> 65 #include <utmp.h> 66 67 int logging; 68 int debug = 0; 69 #define dsyslog if (debug) syslog 70 71 #define MAXIDLE 120 72 73 char hostname[MAXHOSTNAMELEN+1]; 74 struct utmp *utmp = NULL; 75 time_t lastmsgtime; 76 int nutmp, uf; 77 78 void jkfprintf (FILE *, char[], off_t); 79 void mailfor (char *); 80 void notify (struct utmp *, off_t); 81 void onalrm (int); 82 void reapchildren (int); 83 84 int 85 main(int argc, char *argv[]) 86 { 87 struct sockaddr_storage from; 88 int cc, ch; 89 int fromlen; 90 char msgbuf[100]; 91 sigset_t nsigset; 92 93 /* verify proper invocation */ 94 fromlen = sizeof(from); 95 if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0) { 96 (void)fprintf(stderr, 97 "comsat: getsockname: %s.\n", strerror(errno)); 98 exit(1); 99 } 100 101 openlog("comsat", LOG_PID, LOG_DAEMON); 102 while ((ch = getopt(argc, argv, "l")) != -1) 103 switch (ch) { 104 case 'l': 105 logging = 1; 106 break; 107 default: 108 syslog(LOG_ERR, "Usage: %s [-l]", getprogname()); 109 exit(1); 110 } 111 if (chdir(_PATH_MAILDIR)) { 112 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR); 113 (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 114 exit(1); 115 } 116 if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) { 117 syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP); 118 (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 119 exit(1); 120 } 121 (void)time(&lastmsgtime); 122 (void)gethostname(hostname, sizeof(hostname)); 123 hostname[sizeof(hostname) - 1] = '\0'; 124 onalrm(0); 125 (void)signal(SIGALRM, onalrm); 126 (void)signal(SIGTTOU, SIG_IGN); 127 (void)signal(SIGCHLD, reapchildren); 128 for (;;) { 129 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 130 if (cc <= 0) { 131 if (errno != EINTR) 132 sleep(1); 133 errno = 0; 134 continue; 135 } 136 if (!nutmp) /* no one has logged in yet */ 137 continue; 138 sigemptyset(&nsigset); 139 sigaddset(&nsigset, SIGALRM); 140 sigprocmask(SIG_SETMASK, &nsigset, NULL); 141 msgbuf[cc] = '\0'; 142 (void)time(&lastmsgtime); 143 mailfor(msgbuf); 144 sigemptyset(&nsigset); 145 sigprocmask(SIG_SETMASK, &nsigset, NULL); 146 } 147 } 148 149 void 150 reapchildren(int signo) 151 { 152 153 while (wait3(NULL, WNOHANG, NULL) > 0); 154 } 155 156 void 157 onalrm(int signo) 158 { 159 static u_int utmpsize; /* last malloced size for utmp */ 160 static u_int utmpmtime; /* last modification time for utmp */ 161 struct stat statbf; 162 163 if (time(NULL) - lastmsgtime >= MAXIDLE) 164 exit(0); 165 (void)alarm((u_int)15); 166 (void)fstat(uf, &statbf); 167 if (statbf.st_mtime > utmpmtime) { 168 utmpmtime = statbf.st_mtime; 169 if (statbf.st_size > utmpsize) { 170 utmpsize = statbf.st_size + 10 * sizeof(struct utmp); 171 if ((utmp = realloc(utmp, utmpsize)) == NULL) { 172 syslog(LOG_ERR, "%s", strerror(errno)); 173 exit(1); 174 } 175 } 176 (void)lseek(uf, (off_t)0, SEEK_SET); 177 nutmp = read(uf, utmp, (int)statbf.st_size)/sizeof(struct utmp); 178 } 179 } 180 181 void 182 mailfor(char *name) 183 { 184 struct utmp *utp = &utmp[nutmp]; 185 char *cp, *fn; 186 off_t offset; 187 188 if (!(cp = strchr(name, '@'))) 189 return; 190 *cp = '\0'; 191 errno = 0; 192 offset = strtol(cp + 1, &fn, 10); 193 if (errno == ERANGE) 194 return; 195 if (fn && *fn && *fn != '\n') { 196 /* 197 * Procmail sends messages to comsat with a trailing colon 198 * and a pathname to the folder where the new message was 199 * deposited. Since we can't reliably open only regular 200 * files, we need to ignore these. With one exception: 201 * if it mentions the user's system mailbox. 202 */ 203 char maildir[128]; 204 int l = snprintf(maildir, sizeof(maildir), ":%s/%s", 205 _PATH_MAILDIR, name); 206 if (l > sizeof(maildir) || strcmp(maildir, fn) != 0) 207 return; 208 } 209 while (--utp >= utmp) 210 if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name))) 211 notify(utp, offset); 212 } 213 214 static char *cr; 215 216 void 217 notify(struct utmp *utp, off_t offset) 218 { 219 FILE *tp; 220 struct passwd *p; 221 struct stat stb; 222 struct termios ttybuf; 223 char tty[20], name[sizeof(utmp[0].ut_name) + 1]; 224 225 (void)snprintf(tty, sizeof(tty), "%s%.*s", 226 _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line); 227 if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) { 228 /* A slash is an attempt to break security... */ 229 /* 230 * XXX but what about something like "/dev/pts/5" 231 * that we may one day "support". ? 232 */ 233 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty); 234 return; 235 } 236 if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) { 237 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty); 238 return; 239 } 240 dsyslog(LOG_DEBUG, "notify %s on %s", utp->ut_name, tty); 241 if (fork()) 242 return; 243 (void)signal(SIGALRM, SIG_DFL); 244 (void)alarm((u_int)30); 245 if ((tp = fopen(tty, "w")) == NULL) { 246 dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno)); 247 _exit(1); 248 } 249 (void)tcgetattr(fileno(tp), &ttybuf); 250 cr = (ttybuf.c_oflag & ONLCR) && (ttybuf.c_oflag & OPOST) ? 251 "\n" : "\n\r"; 252 (void)strlcpy(name, utp->ut_name, sizeof(name)); 253 254 /* Set uid/gid/groups to users in case mail drop is on nfs */ 255 if ((p = getpwnam(name)) == NULL || 256 initgroups(p->pw_name, p->pw_gid) < 0 || 257 setgid(p->pw_gid) < 0 || 258 setuid(p->pw_uid) < 0) 259 _exit(1); 260 261 if (logging) 262 syslog(LOG_INFO, "biff message for %s", name); 263 264 (void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s", 265 cr, name, (int)sizeof(hostname), hostname, cr, cr); 266 jkfprintf(tp, name, offset); 267 (void)fclose(tp); 268 _exit(0); 269 } 270 271 void 272 jkfprintf(FILE *tp, char name[], off_t offset) 273 { 274 FILE *fi; 275 int linecnt, charcnt, inheader; 276 char line[BUFSIZ], visline[BUFSIZ*4], *nl; 277 278 if ((fi = fopen(name, "r")) == NULL) 279 return; 280 281 (void)fseek(fi, offset, SEEK_SET); 282 /* 283 * Print the first 7 lines or 560 characters of the new mail 284 * (whichever comes first). Skip header crap other than 285 * From, Subject, To, and Date. 286 */ 287 linecnt = 7; 288 charcnt = 560; 289 inheader = 1; 290 while (fgets(line, sizeof(line), fi) != NULL) { 291 line[sizeof(line) - 1] = '\0'; 292 if (inheader) { 293 if (line[0] == '\n') { 294 inheader = 0; 295 continue; 296 } 297 if (line[0] == ' ' || line[0] == '\t' || 298 (strncasecmp(line, "From:", 5) && 299 strncasecmp(line, "Subject:", 8))) 300 continue; 301 } 302 if (strncmp(line, "From ", 5) == 0) { 303 (void)fprintf(tp, "----%s", cr); 304 (void)fclose(fi); 305 return; 306 } 307 if (linecnt <= 0 || charcnt <= 0) { 308 (void)fprintf(tp, "...more...%s", cr); 309 (void)fclose(fi); 310 return; 311 } 312 if ((nl = strchr(line, '\n')) != NULL) 313 *nl = '\0'; 314 /* strip weird stuff so can't trojan horse stupid terminals */ 315 (void)strvis(visline, line, VIS_CSTYLE); 316 (void)fputs(visline, tp); 317 (void)fputs(cr, tp); 318 --linecnt; 319 } 320 (void)fprintf(tp, "----%s\n", cr); 321 (void)fclose(fi); 322 } 323
Indexes created Tue Sep 23 14:10:03 GMT 2025