1 /* 2 * Copyright (c) 1980, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifndef lint 35 static char copyright[] = 36 "@(#) Copyright (c) 1980, 1993\n\ 37 The Regents of the University of California. All rights reserved.\n"; 38 #endif /* not lint */ 39 40 #ifndef lint 41 /*static char sccsid[] = "from: @(#)comsat.c 8.1 (Berkeley) 6/4/93";*/ 42 static char rcsid[] = "$Id: comsat.c,v 1.6 1994/08/06 23:26:39 jtc Exp $"; 43 #endif /* not lint */ 44 45 #include <sys/param.h> 46 #include <sys/socket.h> 47 #include <sys/stat.h> 48 #include <sys/file.h> 49 #include <sys/wait.h> 50 51 #include <netinet/in.h> 52 53 #include <ctype.h> 54 #include <errno.h> 55 #include <netdb.h> 56 #include <paths.h> 57 #include <pwd.h> 58 #include <sgtty.h> 59 #include <signal.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <syslog.h> 64 #include <unistd.h> 65 #include <utmp.h> 66 67 int debug = 0; 68 #define dsyslog if (debug) syslog 69 70 #define MAXIDLE 120 71 72 char hostname[MAXHOSTNAMELEN]; 73 struct utmp *utmp = NULL; 74 time_t lastmsgtime; 75 int nutmp, uf; 76 77 void jkfprintf __P((FILE *, char[], off_t)); 78 void mailfor __P((char *)); 79 void notify __P((struct utmp *, off_t)); 80 void onalrm __P((int)); 81 void reapchildren __P((int)); 82 83 int 84 main(argc, argv) 85 int argc; 86 char *argv[]; 87 { 88 struct sockaddr_in from; 89 register int cc; 90 int fromlen; 91 char msgbuf[100]; 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 openlog("comsat", LOG_PID, LOG_DAEMON); 101 if (chdir(_PATH_MAILDIR)) { 102 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR); 103 (void) recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 104 exit(1); 105 } 106 if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) { 107 syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP); 108 (void) recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 109 exit(1); 110 } 111 (void)time(&lastmsgtime); 112 (void)gethostname(hostname, sizeof(hostname)); 113 onalrm(0); 114 (void)signal(SIGALRM, onalrm); 115 (void)signal(SIGTTOU, SIG_IGN); 116 (void)signal(SIGCHLD, reapchildren); 117 for (;;) { 118 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 119 if (cc <= 0) { 120 if (errno != EINTR) 121 sleep(1); 122 errno = 0; 123 continue; 124 } 125 if (!nutmp) /* no one has logged in yet */ 126 continue; 127 sigblock(sigmask(SIGALRM)); 128 msgbuf[cc] = '\0'; 129 (void)time(&lastmsgtime); 130 mailfor(msgbuf); 131 sigsetmask(0L); 132 } 133 } 134 135 void 136 reapchildren(signo) 137 int signo; 138 { 139 while (wait3(NULL, WNOHANG, NULL) > 0); 140 } 141 142 void 143 onalrm(signo) 144 int signo; 145 { 146 static u_int utmpsize; /* last malloced size for utmp */ 147 static u_int utmpmtime; /* last modification time for utmp */ 148 struct stat statbf; 149 150 if (time(NULL) - lastmsgtime >= MAXIDLE) 151 exit(0); 152 (void)alarm((u_int)15); 153 (void)fstat(uf, &statbf); 154 if (statbf.st_mtime > utmpmtime) { 155 utmpmtime = statbf.st_mtime; 156 if (statbf.st_size > utmpsize) { 157 utmpsize = statbf.st_size + 10 * sizeof(struct utmp); 158 if ((utmp = realloc(utmp, utmpsize)) == NULL) { 159 syslog(LOG_ERR, "%s", strerror(errno)); 160 exit(1); 161 } 162 } 163 (void)lseek(uf, (off_t)0, L_SET); 164 nutmp = read(uf, utmp, (int)statbf.st_size)/sizeof(struct utmp); 165 } 166 } 167 168 void 169 mailfor(name) 170 char *name; 171 { 172 register struct utmp *utp = &utmp[nutmp]; 173 register char *cp; 174 off_t offset; 175 176 if (!(cp = strchr(name, '@'))) 177 return; 178 *cp = '\0'; 179 offset = atoi(cp + 1); 180 while (--utp >= utmp) 181 if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name))) 182 notify(utp, offset); 183 } 184 185 static char *cr; 186 187 void 188 notify(utp, offset) 189 register struct utmp *utp; 190 off_t offset; 191 { 192 FILE *tp; 193 struct stat stb; 194 struct sgttyb gttybuf; 195 char tty[20], name[sizeof(utmp[0].ut_name) + 1]; 196 197 (void)snprintf(tty, sizeof(tty), "%s%.*s", 198 _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line); 199 if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) { 200 /* A slash is an attempt to break security... */ 201 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty); 202 return; 203 } 204 if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) { 205 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty); 206 return; 207 } 208 dsyslog(LOG_DEBUG, "notify %s on %s\n", utp->ut_name, tty); 209 if (fork()) 210 return; 211 (void)signal(SIGALRM, SIG_DFL); 212 (void)alarm((u_int)30); 213 if ((tp = fopen(tty, "w")) == NULL) { 214 dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno)); 215 _exit(-1); 216 } 217 (void)ioctl(fileno(tp), TIOCGETP, >tybuf); 218 cr = (gttybuf.sg_flags&CRMOD) && !(gttybuf.sg_flags&RAW) ? 219 "\n" : "\n\r"; 220 (void)strncpy(name, utp->ut_name, sizeof(utp->ut_name)); 221 name[sizeof(name) - 1] = '\0'; 222 (void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s", 223 cr, name, (int)sizeof(hostname), hostname, cr, cr); 224 jkfprintf(tp, name, offset); 225 (void)fclose(tp); 226 _exit(0); 227 } 228 229 void 230 jkfprintf(tp, name, offset) 231 register FILE *tp; 232 char name[]; 233 off_t offset; 234 { 235 register char *cp, ch; 236 register FILE *fi; 237 register int linecnt, charcnt, inheader; 238 register struct passwd *p; 239 char line[BUFSIZ]; 240 241 /* Set effective uid to user in case mail drop is on nfs */ 242 if ((p = getpwnam(name)) != NULL) 243 (void) setuid(p->pw_uid); 244 245 if ((fi = fopen(name, "r")) == NULL) 246 return; 247 248 (void)fseek(fi, offset, L_SET); 249 /* 250 * Print the first 7 lines or 560 characters of the new mail 251 * (whichever comes first). Skip header crap other than 252 * From, Subject, To, and Date. 253 */ 254 linecnt = 7; 255 charcnt = 560; 256 inheader = 1; 257 while (fgets(line, sizeof(line), fi) != NULL) { 258 if (inheader) { 259 if (line[0] == '\n') { 260 inheader = 0; 261 continue; 262 } 263 if (line[0] == ' ' || line[0] == '\t' || 264 strncmp(line, "From:", 5) && 265 strncmp(line, "Subject:", 8)) 266 continue; 267 } 268 if (linecnt <= 0 || charcnt <= 0) { 269 (void)fprintf(tp, "...more...%s", cr); 270 (void)fclose(fi); 271 return; 272 } 273 /* strip weird stuff so can't trojan horse stupid terminals */ 274 for (cp = line; (ch = *cp) && ch != '\n'; ++cp, --charcnt) { 275 ch = toascii(ch); 276 if (!isprint(ch) && !isspace(ch)) 277 ch |= 0x40; 278 (void)fputc(ch, tp); 279 } 280 (void)fputs(cr, tp); 281 --linecnt; 282 } 283 (void)fprintf(tp, "----%s\n", cr); 284 (void)fclose(fi); 285 } 286