1 /* $NetBSD: comsat.c,v 1.17 2000/10/04 18:52:50 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 1.17 2000/10/04 18:52:50 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 extern char *__progname; 97 98 /* verify proper invocation */ 99 fromlen = sizeof(from); 100 if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0) { 101 (void)fprintf(stderr, 102 "comsat: getsockname: %s.\n", strerror(errno)); 103 exit(1); 104 } 105 106 openlog("comsat", LOG_PID, LOG_DAEMON); 107 while ((ch = getopt(argc, argv, "l")) != -1) 108 switch (ch) { 109 case 'l': 110 logging = 1; 111 break; 112 default: 113 syslog(LOG_ERR, "usage: %s [-l]", __progname); 114 exit(1); 115 } 116 if (chdir(_PATH_MAILDIR)) { 117 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR); 118 (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 119 exit(1); 120 } 121 if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) { 122 syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP); 123 (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 124 exit(1); 125 } 126 (void)time(&lastmsgtime); 127 (void)gethostname(hostname, sizeof(hostname)); 128 hostname[sizeof(hostname) - 1] = '\0'; 129 onalrm(0); 130 (void)signal(SIGALRM, onalrm); 131 (void)signal(SIGTTOU, SIG_IGN); 132 (void)signal(SIGCHLD, reapchildren); 133 for (;;) { 134 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 135 if (cc <= 0) { 136 if (errno != EINTR) 137 sleep(1); 138 errno = 0; 139 continue; 140 } 141 if (!nutmp) /* no one has logged in yet */ 142 continue; 143 sigemptyset(&sigset); 144 sigaddset(&sigset, SIGALRM); 145 sigprocmask(SIG_SETMASK, &sigset, NULL); 146 msgbuf[cc] = '\0'; 147 (void)time(&lastmsgtime); 148 mailfor(msgbuf); 149 sigemptyset(&sigset); 150 sigprocmask(SIG_SETMASK, &sigset, NULL); 151 } 152 } 153 154 void 155 reapchildren(int signo) 156 { 157 158 while (wait3(NULL, WNOHANG, NULL) > 0); 159 } 160 161 void 162 onalrm(int signo) 163 { 164 static u_int utmpsize; /* last malloced size for utmp */ 165 static u_int utmpmtime; /* last modification time for utmp */ 166 struct stat statbf; 167 168 if (time(NULL) - lastmsgtime >= MAXIDLE) 169 exit(0); 170 (void)alarm((u_int)15); 171 (void)fstat(uf, &statbf); 172 if (statbf.st_mtime > utmpmtime) { 173 utmpmtime = statbf.st_mtime; 174 if (statbf.st_size > utmpsize) { 175 utmpsize = statbf.st_size + 10 * sizeof(struct utmp); 176 if ((utmp = realloc(utmp, utmpsize)) == NULL) { 177 syslog(LOG_ERR, "%s", strerror(errno)); 178 exit(1); 179 } 180 } 181 (void)lseek(uf, (off_t)0, SEEK_SET); 182 nutmp = read(uf, utmp, (int)statbf.st_size)/sizeof(struct utmp); 183 } 184 } 185 186 void 187 mailfor(char *name) 188 { 189 struct utmp *utp = &utmp[nutmp]; 190 char *cp; 191 off_t offset; 192 193 if (!(cp = strchr(name, '@'))) 194 return; 195 *cp = '\0'; 196 offset = atoi(cp + 1); 197 while (--utp >= utmp) 198 if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name))) 199 notify(utp, offset); 200 } 201 202 static char *cr; 203 204 void 205 notify(struct utmp *utp, off_t offset) 206 { 207 FILE *tp; 208 struct passwd *p; 209 struct stat stb; 210 struct termios ttybuf; 211 char tty[20], name[sizeof(utmp[0].ut_name) + 1]; 212 213 (void)snprintf(tty, sizeof(tty), "%s%.*s", 214 _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line); 215 if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) { 216 /* A slash is an attempt to break security... */ 217 /* 218 * XXX but what about something like "/dev/pts/5" 219 * that we may one day "support". ? 220 */ 221 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty); 222 return; 223 } 224 if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) { 225 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty); 226 return; 227 } 228 dsyslog(LOG_DEBUG, "notify %s on %s", utp->ut_name, tty); 229 if (fork()) 230 return; 231 (void)signal(SIGALRM, SIG_DFL); 232 (void)alarm((u_int)30); 233 if ((tp = fopen(tty, "w")) == NULL) { 234 dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno)); 235 _exit(1); 236 } 237 (void)tcgetattr(fileno(tp), &ttybuf); 238 cr = (ttybuf.c_oflag & ONLCR) && (ttybuf.c_oflag & OPOST) ? 239 "\n" : "\n\r"; 240 (void)strncpy(name, utp->ut_name, sizeof(name)); 241 name[sizeof(name) - 1] = '\0'; 242 243 /* Set uid/gid/groups to users in case mail drop is on nfs */ 244 if ((p = getpwnam(name)) == NULL || 245 initgroups(p->pw_name, p->pw_gid) < 0 || 246 setgid(p->pw_gid) < 0 || 247 setuid(p->pw_uid) < 0) 248 _exit(1); 249 250 if (logging) 251 syslog(LOG_INFO, "biff message for %s", name); 252 253 (void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s", 254 cr, name, (int)sizeof(hostname), hostname, cr, cr); 255 jkfprintf(tp, name, offset); 256 (void)fclose(tp); 257 _exit(0); 258 } 259 260 void 261 jkfprintf(FILE *tp, char name[], off_t offset) 262 { 263 FILE *fi; 264 int linecnt, charcnt, inheader; 265 char line[BUFSIZ], visline[BUFSIZ*4]; 266 267 if ((fi = fopen(name, "r")) == NULL) 268 return; 269 270 (void)fseek(fi, offset, SEEK_SET); 271 /* 272 * Print the first 7 lines or 560 characters of the new mail 273 * (whichever comes first). Skip header crap other than 274 * From, Subject, To, and Date. 275 */ 276 linecnt = 7; 277 charcnt = 560; 278 inheader = 1; 279 while (fgets(line, sizeof(line), fi) != NULL) { 280 if (inheader) { 281 if (line[0] == '\n') { 282 inheader = 0; 283 continue; 284 } 285 if (line[0] == ' ' || line[0] == '\t' || 286 (strncasecmp(line, "From:", 5) && 287 strncasecmp(line, "Subject:", 8))) 288 continue; 289 } 290 if (linecnt <= 0 || charcnt <= 0) { 291 (void)fprintf(tp, "...more...%s", cr); 292 (void)fclose(fi); 293 return; 294 } 295 /* strip weird stuff so can't trojan horse stupid terminals */ 296 (void)strvis(visline, line, VIS_CSTYLE); 297 fputs(visline, tp); 298 --linecnt; 299 } 300 (void)fprintf(tp, "----%s\n", cr); 301 (void)fclose(fi); 302 } 303