comsat.c revision 1.13
1 /* $NetBSD: comsat.c,v 1.13 1998/07/04 19:38:39 mrg 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 1.13 1998/07/04 19:38:39 mrg 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 __P((FILE *, char[], off_t)); 83 void mailfor __P((char *)); 84 void notify __P((struct utmp *, off_t)); 85 void onalrm __P((int)); 86 void reapchildren __P((int)); 87 int main __P((int, char *[])); 88 89 int 90 main(argc, argv) 91 int argc; 92 char *argv[]; 93 { 94 struct sockaddr_in from; 95 int cc, ch; 96 int fromlen; 97 char msgbuf[100]; 98 sigset_t sigset; 99 extern char *__progname; 100 101 /* verify proper invocation */ 102 fromlen = sizeof(from); 103 if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0) { 104 (void)fprintf(stderr, 105 "comsat: getsockname: %s.\n", strerror(errno)); 106 exit(1); 107 } 108 109 openlog("comsat", LOG_PID, LOG_DAEMON); 110 while ((ch = getopt(argc, argv, "l")) != -1) 111 switch (ch) { 112 case 'l': 113 logging = 1; 114 break; 115 default: 116 syslog(LOG_ERR, "usage: %s [-l]", __progname); 117 exit(1); 118 } 119 if (chdir(_PATH_MAILDIR)) { 120 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR); 121 (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 122 exit(1); 123 } 124 if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) { 125 syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP); 126 (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 127 exit(1); 128 } 129 (void)time(&lastmsgtime); 130 (void)gethostname(hostname, sizeof(hostname)); 131 onalrm(0); 132 (void)signal(SIGALRM, onalrm); 133 (void)signal(SIGTTOU, SIG_IGN); 134 (void)signal(SIGCHLD, reapchildren); 135 for (;;) { 136 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 137 if (cc <= 0) { 138 if (errno != EINTR) 139 sleep(1); 140 errno = 0; 141 continue; 142 } 143 if (!nutmp) /* no one has logged in yet */ 144 continue; 145 sigemptyset(&sigset); 146 sigaddset(&sigset, SIGALRM); 147 sigprocmask(SIG_SETMASK, &sigset, NULL); 148 msgbuf[cc] = '\0'; 149 (void)time(&lastmsgtime); 150 mailfor(msgbuf); 151 sigemptyset(&sigset); 152 sigprocmask(SIG_SETMASK, &sigset, NULL); 153 } 154 } 155 156 void 157 reapchildren(signo) 158 int signo; 159 { 160 161 while (wait3(NULL, WNOHANG, NULL) > 0); 162 } 163 164 void 165 onalrm(signo) 166 int signo; 167 { 168 static u_int utmpsize; /* last malloced size for utmp */ 169 static u_int utmpmtime; /* last modification time for utmp */ 170 struct stat statbf; 171 172 if (time(NULL) - lastmsgtime >= MAXIDLE) 173 exit(0); 174 (void)alarm((u_int)15); 175 (void)fstat(uf, &statbf); 176 if (statbf.st_mtime > utmpmtime) { 177 utmpmtime = statbf.st_mtime; 178 if (statbf.st_size > utmpsize) { 179 utmpsize = statbf.st_size + 10 * sizeof(struct utmp); 180 if ((utmp = realloc(utmp, utmpsize)) == NULL) { 181 syslog(LOG_ERR, "%s", strerror(errno)); 182 exit(1); 183 } 184 } 185 (void)lseek(uf, (off_t)0, SEEK_SET); 186 nutmp = read(uf, utmp, (int)statbf.st_size)/sizeof(struct utmp); 187 } 188 } 189 190 void 191 mailfor(name) 192 char *name; 193 { 194 struct utmp *utp = &utmp[nutmp]; 195 char *cp; 196 off_t offset; 197 198 if (!(cp = strchr(name, '@'))) 199 return; 200 *cp = '\0'; 201 offset = atoi(cp + 1); 202 while (--utp >= utmp) 203 if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name))) 204 notify(utp, offset); 205 } 206 207 static char *cr; 208 209 void 210 notify(utp, offset) 211 struct utmp *utp; 212 off_t offset; 213 { 214 FILE *tp; 215 struct passwd *p; 216 struct stat stb; 217 struct termios ttybuf; 218 char tty[20], name[sizeof(utmp[0].ut_name) + 1]; 219 220 (void)snprintf(tty, sizeof(tty), "%s%.*s", 221 _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line); 222 if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) { 223 /* A slash is an attempt to break security... */ 224 /* 225 * XXX but what about something like "/dev/pts/5" 226 * that we may one day "support". ? 227 */ 228 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty); 229 return; 230 } 231 if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) { 232 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty); 233 return; 234 } 235 dsyslog(LOG_DEBUG, "notify %s on %s\n", utp->ut_name, tty); 236 if (fork()) 237 return; 238 (void)signal(SIGALRM, SIG_DFL); 239 (void)alarm((u_int)30); 240 if ((tp = fopen(tty, "w")) == NULL) { 241 dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno)); 242 _exit(-1); 243 } 244 (void)tcgetattr(fileno(tp), &ttybuf); 245 cr = (ttybuf.c_oflag & ONLCR) && (ttybuf.c_oflag & OPOST) ? 246 "\n" : "\n\r"; 247 (void)strncpy(name, utp->ut_name, sizeof(utp->ut_name)); 248 name[sizeof(name) - 1] = '\0'; 249 250 /* Set uid/gid/groups to users in case mail drop is on nfs */ 251 if ((p = getpwnam(name)) == NULL || 252 initgroups(p->pw_name, p->pw_gid) < 0 || 253 setgid(p->pw_gid) < 0 || 254 setuid(p->pw_uid) < 0) 255 _exit(-1); 256 257 if (logging) 258 syslog(LOG_INFO, "biff message for %s", name); 259 260 (void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s", 261 cr, name, (int)sizeof(hostname), hostname, cr, cr); 262 jkfprintf(tp, name, offset); 263 (void)fclose(tp); 264 _exit(0); 265 } 266 267 void 268 jkfprintf(tp, name, offset) 269 FILE *tp; 270 char name[]; 271 off_t offset; 272 { 273 FILE *fi; 274 int linecnt, charcnt, inheader; 275 char line[BUFSIZ], visline[BUFSIZ*4]; 276 277 if ((fi = fopen(name, "r")) == NULL) 278 return; 279 280 (void)fseek(fi, offset, SEEK_SET); 281 /* 282 * Print the first 7 lines or 560 characters of the new mail 283 * (whichever comes first). Skip header crap other than 284 * From, Subject, To, and Date. 285 */ 286 linecnt = 7; 287 charcnt = 560; 288 inheader = 1; 289 while (fgets(line, sizeof(line), fi) != NULL) { 290 if (inheader) { 291 if (line[0] == '\n') { 292 inheader = 0; 293 continue; 294 } 295 if (line[0] == ' ' || line[0] == '\t' || 296 (strncasecmp(line, "From:", 5) && 297 strncasecmp(line, "Subject:", 8))) 298 continue; 299 } 300 if (linecnt <= 0 || charcnt <= 0) { 301 (void)fprintf(tp, "...more...%s", cr); 302 (void)fclose(fi); 303 return; 304 } 305 /* strip weird stuff so can't trojan horse stupid terminals */ 306 (void)strvis(visline, line, VIS_CSTYLE); 307 fputs(visline, tp); 308 --linecnt; 309 } 310 (void)fprintf(tp, "----%s\n", cr); 311 (void)fclose(fi); 312 } 313
Indexes created Wed Sep 24 15:09:51 GMT 2025