1/* $NetBSD: comsat.c,v 1.14 1998/07/06 06:47:38 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 41static char sccsid[] = "from: @(#)comsat.c 8.1 (Berkeley) 6/4/93"; 42#else 43__RCSID("$NetBSD: comsat.c,v 1.14 1998/07/06 06:47:38 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 <utmpx.h> 70 71int logging; 72int debug = 0; 73#define dsyslog if (debug) syslog 74 75#define MAXIDLE 120 76 77char hostname[MAXHOSTNAMELEN+1]; 78struct utmpx *utmpx = NULL; 79time_t lastmsgtime; 80int nutmpx, uf; 81 82void jkfprintf __P((FILE *, char[], off_t)); 83void mailfor __P((char *)); 84void notify __P((struct utmpx *, off_t)); 85void onalrm __P((int)); 86void reapchildren __P((int)); 87int main __P((int, char *[])); 88 89int 90main(argc, argv) 91 int argc; 92 char *argv[]; 93{ 94 struct sockaddr_in from; 95 int cc, ch; 96 socklen_t 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_UTMPX, O_RDONLY, 0)) < 0) { 125 syslog(LOG_ERR, "open: %s: %m", _PATH_UTMPX); 126 (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 127 exit(1); 128 } 129 (void)time(&lastmsgtime); 130 (void)gethostname(hostname, sizeof(hostname)); 131 hostname[sizeof(hostname) - 1] = '\0'; 132 onalrm(0); 133 (void)signal(SIGALRM, onalrm); 134 (void)signal(SIGTTOU, SIG_IGN); 135 (void)signal(SIGCHLD, reapchildren); 136 for (;;) { 137 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0); 138 if (cc <= 0) { 139 if (errno != EINTR) 140 sleep(1); 141 errno = 0; 142 continue; 143 } 144 if (!nutmpx) /* no one has logged in yet */ 145 continue; 146 sigemptyset(&sigset); 147 sigaddset(&sigset, SIGALRM); 148 sigprocmask(SIG_SETMASK, &sigset, NULL); 149 msgbuf[cc] = '\0'; 150 (void)time(&lastmsgtime); 151 mailfor(msgbuf); 152 sigemptyset(&sigset); 153 sigprocmask(SIG_SETMASK, &sigset, NULL); 154 } 155} 156 157void 158reapchildren(signo) 159 int signo; 160{ 161 162 while (wait3(NULL, WNOHANG, NULL) > 0); 163} 164 165void 166onalrm(signo) 167 int signo; 168{ 169 static u_int utmpxsize; /* last malloced size for utmpx */ 170 static time_t utmpxmtime; /* last modification time for utmpx */ 171 struct stat statbf; 172 173 if (time(NULL) - lastmsgtime >= MAXIDLE) 174 exit(0); 175 (void)alarm((u_int)15); 176 (void)fstat(uf, &statbf); 177 if (statbf.st_mtime > utmpxmtime) { 178 utmpxmtime = statbf.st_mtime; 179 if (statbf.st_size > utmpxsize) { 180 utmpxsize = statbf.st_size + 10 * sizeof(struct utmpx); 181 if ((utmpx = realloc(utmpx, utmpxsize)) == NULL) { 182 syslog(LOG_ERR, "%s", strerror(errno)); 183 exit(1); 184 } 185 } 186 /* the first record is just a signature, so it is skipped */ 187 (void)lseek(uf, (off_t)sizeof(struct utmpx), SEEK_SET); 188 nutmpx = read(uf, utmpx, statbf.st_size - sizeof(struct utmpx))/sizeof(struct utmpx); 189 } 190} 191 192void 193mailfor(name) 194 char *name; 195{ 196 struct utmpx *utp = &utmpx[nutmpx]; 197 char *cp; 198 off_t offset; 199 200 if (!(cp = strchr(name, '@'))) 201 return; 202 *cp = '\0'; 203 offset = atoi(cp + 1); 204 while (--utp >= utmpx) 205 if (utp->ut_type == USER_PROCESS && !strncmp(utp->ut_user, name, sizeof(utp->ut_user))) 206 notify(utp, offset); 207} 208 209static char *cr; 210 211void 212notify(utp, offset) 213 struct utmpx *utp; 214 off_t offset; 215{ 216 FILE *tp; 217 struct passwd *p; 218 struct stat stb; 219 struct termios ttybuf; 220 char tty[40], name[sizeof(utp->ut_user) + 1]; 221 222 (void)snprintf(tty, sizeof(tty), "%s%.*s", 223 _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line); 224 if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) { 225 /* A slash is an attempt to break security... */ 226 /* 227 * XXX but what about something like "/dev/pts/5" 228 * that we may one day "support". ? 229 */ 230 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty); 231 return; 232 } 233 if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) { 234 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_user, tty); 235 return; 236 } 237 dsyslog(LOG_DEBUG, "notify %s on %s\n", utp->ut_user, tty); 238 if (fork()) 239 return; 240 (void)signal(SIGALRM, SIG_DFL); 241 (void)alarm((u_int)30); 242 if ((tp = fopen(tty, "w")) == NULL) { 243 dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno)); 244 _exit(-1); 245 } 246 (void)tcgetattr(fileno(tp), &ttybuf); 247 cr = (ttybuf.c_oflag & ONLCR) && (ttybuf.c_oflag & OPOST) ? 248 "\n" : "\n\r"; 249 (void)strncpy(name, utp->ut_user, sizeof(utp->ut_user)); 250 name[sizeof(name) - 1] = '\0'; 251 252 /* Set uid/gid/groups to users in case mail drop is on nfs */ 253 if ((p = getpwnam(name)) == NULL || 254 initgroups(p->pw_name, p->pw_gid) < 0 || 255 setgid(p->pw_gid) < 0 || 256 setuid(p->pw_uid) < 0) 257 _exit(-1); 258 259 if (logging) 260 syslog(LOG_INFO, "biff message for %s", name); 261 262 (void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s", 263 cr, name, (int)sizeof(hostname), hostname, cr, cr); 264 jkfprintf(tp, name, offset); 265 (void)fclose(tp); 266 _exit(0); 267} 268 269void 270jkfprintf(tp, name, offset) 271 FILE *tp; 272 char name[]; 273 off_t offset; 274{ 275 FILE *fi; 276 int linecnt, charcnt, inheader; 277 char line[BUFSIZ], visline[BUFSIZ*4]; 278 279 if ((fi = fopen(name, "r")) == NULL) 280 return; 281 282 (void)fseek(fi, offset, SEEK_SET); 283 /* 284 * Print the first 7 lines or 560 characters of the new mail 285 * (whichever comes first). Skip header crap other than 286 * From, Subject, To, and Date. 287 */ 288 linecnt = 7; 289 charcnt = 560; 290 inheader = 1; 291 while (fgets(line, sizeof(line), fi) != NULL) { 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 (linecnt <= 0 || charcnt <= 0) { 303 (void)fprintf(tp, "...more...%s", cr); 304 (void)fclose(fi); 305 return; 306 } 307 /* strip weird stuff so can't trojan horse stupid terminals */ 308 (void)strvis(visline, line, VIS_CSTYLE); 309 fputs(visline, tp); 310 --linecnt; 311 } 312 (void)fprintf(tp, "----%s\n", cr); 313 (void)fclose(fi); 314} 315