comsat.c revision 1.9
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 1.9 1997/08/25 19:31:47 kleink 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 <signal.h> 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 #include <syslog.h> 63 #include <termios.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 sigset_t sigset; 93 94 /* verify proper invocation */ 95 fromlen = sizeof(from); 96 if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0) { 97 (void)fprintf(stderr, 98 "comsat: getsockname: %s.\n", strerror(errno)); 99 exit(1); 100 } 101 openlog("comsat", LOG_PID, LOG_DAEMON); 102 if (chdir(_PATH_MAILDIR)) { 103 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR); 104 (void) recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 105 exit(1); 106 } 107 if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) { 108 syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP); 109 (void) recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 110 exit(1); 111 } 112 (void)time(&lastmsgtime); 113 (void)gethostname(hostname, sizeof(hostname)); 114 onalrm(0); 115 (void)signal(SIGALRM, onalrm); 116 (void)signal(SIGTTOU, SIG_IGN); 117 (void)signal(SIGCHLD, reapchildren); 118 for (;;) { 119 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 120 if (cc <= 0) { 121 if (errno != EINTR) 122 sleep(1); 123 errno = 0; 124 continue; 125 } 126 if (!nutmp) /* no one has logged in yet */ 127 continue; 128 sigemptyset(&sigset); 129 sigaddset(&sigset, SIGALRM); 130 sigprocmask(SIG_SETMASK, &sigset, NULL); 131 msgbuf[cc] = '\0'; 132 (void)time(&lastmsgtime); 133 mailfor(msgbuf); 134 sigemptyset(&sigset); 135 sigprocmask(SIG_SETMASK, &sigset, NULL); 136 } 137 } 138 139 void 140 reapchildren(signo) 141 int signo; 142 { 143 while (wait3(NULL, WNOHANG, NULL) > 0); 144 } 145 146 void 147 onalrm(signo) 148 int signo; 149 { 150 static u_int utmpsize; /* last malloced size for utmp */ 151 static u_int utmpmtime; /* last modification time for utmp */ 152 struct stat statbf; 153 154 if (time(NULL) - lastmsgtime >= MAXIDLE) 155 exit(0); 156 (void)alarm((u_int)15); 157 (void)fstat(uf, &statbf); 158 if (statbf.st_mtime > utmpmtime) { 159 utmpmtime = statbf.st_mtime; 160 if (statbf.st_size > utmpsize) { 161 utmpsize = statbf.st_size + 10 * sizeof(struct utmp); 162 if ((utmp = realloc(utmp, utmpsize)) == NULL) { 163 syslog(LOG_ERR, "%s", strerror(errno)); 164 exit(1); 165 } 166 } 167 (void)lseek(uf, (off_t)0, SEEK_SET); 168 nutmp = read(uf, utmp, (int)statbf.st_size)/sizeof(struct utmp); 169 } 170 } 171 172 void 173 mailfor(name) 174 char *name; 175 { 176 register struct utmp *utp = &utmp[nutmp]; 177 register char *cp; 178 off_t offset; 179 180 if (!(cp = strchr(name, '@'))) 181 return; 182 *cp = '\0'; 183 offset = atoi(cp + 1); 184 while (--utp >= utmp) 185 if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name))) 186 notify(utp, offset); 187 } 188 189 static char *cr; 190 191 void 192 notify(utp, offset) 193 register struct utmp *utp; 194 off_t offset; 195 { 196 FILE *tp; 197 struct stat stb; 198 struct termios ttybuf; 199 char tty[20], name[sizeof(utmp[0].ut_name) + 1]; 200 201 (void)snprintf(tty, sizeof(tty), "%s%.*s", 202 _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line); 203 if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) { 204 /* A slash is an attempt to break security... */ 205 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty); 206 return; 207 } 208 if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) { 209 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty); 210 return; 211 } 212 dsyslog(LOG_DEBUG, "notify %s on %s\n", utp->ut_name, tty); 213 if (fork()) 214 return; 215 (void)signal(SIGALRM, SIG_DFL); 216 (void)alarm((u_int)30); 217 if ((tp = fopen(tty, "w")) == NULL) { 218 dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno)); 219 _exit(-1); 220 } 221 (void)tcgetattr(fileno(tp), &ttybuf); 222 cr = (ttybuf.c_oflag & ONLCR) && (ttybuf.c_oflag & OPOST) ? 223 "\n" : "\n\r"; 224 (void)strncpy(name, utp->ut_name, sizeof(utp->ut_name)); 225 name[sizeof(name) - 1] = '\0'; 226 (void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s", 227 cr, name, (int)sizeof(hostname), hostname, cr, cr); 228 jkfprintf(tp, name, offset); 229 (void)fclose(tp); 230 _exit(0); 231 } 232 233 void 234 jkfprintf(tp, name, offset) 235 register FILE *tp; 236 char name[]; 237 off_t offset; 238 { 239 register char *cp, ch; 240 register FILE *fi; 241 register int linecnt, charcnt, inheader; 242 register struct passwd *p; 243 char line[BUFSIZ]; 244 245 /* Set effective uid to user in case mail drop is on nfs */ 246 if ((p = getpwnam(name)) != NULL) 247 (void) setuid(p->pw_uid); 248 249 if ((fi = fopen(name, "r")) == NULL) 250 return; 251 252 (void)fseek(fi, offset, SEEK_SET); 253 /* 254 * Print the first 7 lines or 560 characters of the new mail 255 * (whichever comes first). Skip header crap other than 256 * From, Subject, To, and Date. 257 */ 258 linecnt = 7; 259 charcnt = 560; 260 inheader = 1; 261 while (fgets(line, sizeof(line), fi) != NULL) { 262 if (inheader) { 263 if (line[0] == '\n') { 264 inheader = 0; 265 continue; 266 } 267 if (line[0] == ' ' || line[0] == '\t' || 268 strncmp(line, "From:", 5) && 269 strncmp(line, "Subject:", 8)) 270 continue; 271 } 272 if (linecnt <= 0 || charcnt <= 0) { 273 (void)fprintf(tp, "...more...%s", cr); 274 (void)fclose(fi); 275 return; 276 } 277 /* strip weird stuff so can't trojan horse stupid terminals */ 278 for (cp = line; (ch = *cp) && ch != '\n'; ++cp, --charcnt) { 279 ch = toascii(ch); 280 if (!isprint(ch) && !isspace(ch)) 281 ch |= 0x40; 282 (void)fputc(ch, tp); 283 } 284 (void)fputs(cr, tp); 285 --linecnt; 286 } 287 (void)fprintf(tp, "----%s\n", cr); 288 (void)fclose(fi); 289 } 290
Indexes created Tue Sep 23 14:10:03 GMT 2025