libexec/comsat/comsat.c

   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 const 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 #if 0
  42 static char sccsid[] = "@(#)comsat.c    8.1 (Berkeley) 6/4/93";
  43 #endif
  44 static const char rcsid[] =
  45   "$FreeBSD$";
  46 #endif /* not lint */
  47
  48 #include <sys/param.h>
  49 #include <sys/socket.h>
  50 #include <sys/stat.h>
  51 #include <sys/file.h>
  52 #include <sys/wait.h>
  53
  54 #include <netinet/in.h>
  55
  56 #include <ctype.h>
  57 #include <err.h>
  58 #include <errno.h>
  59 #include <netdb.h>
  60 #include <paths.h>
  61 #include <pwd.h>
  62 #include <termios.h>
  63 #include <signal.h>
  64 #include <stdio.h>
  65 #include <stdlib.h>
  66 #include <string.h>
  67 #include <syslog.h>
  68 #include <unistd.h>
  69 #include <utmp.h>
  70
  71 int     debug = 0;
  72 #define dsyslog if (debug) syslog
  73
  74 #define MAXIDLE 120
  75
  76 char    hostname[MAXHOSTNAMELEN];
  77 struct  utmp *utmp = NULL;
  78 time_t  lastmsgtime;
  79 int     nutmp, uf;
  80
  81 void jkfprintf(FILE *, char[], char[], off_t);
  82 void mailfor(char *);
  83 void notify(struct utmp *, char[], off_t, int);
  84 void onalrm(int);
  85 void reapchildren(int);
  86
  87 int
  88 main(int argc, char *argv[])
  89 {
  90         struct sockaddr_in from;
  91         socklen_t fromlen;
  92         int cc;
  93         char msgbuf[256];
  94
  95         /* verify proper invocation */
  96         fromlen = sizeof(from);
  97         if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0)
  98                 err(1, "getsockname");
  99         openlog("comsat", LOG_PID, LOG_DAEMON);
 100         if (chdir(_PATH_MAILDIR)) {
 101                 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR);
 102                 (void) recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
 103                 exit(1);
 104         }
 105         if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) {
 106                 syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP);
 107                 (void) recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
 108                 exit(1);
 109         }
 110         (void)time(&lastmsgtime);
 111         (void)gethostname(hostname, sizeof(hostname));
 112         onalrm(0);
 113         (void)signal(SIGALRM, onalrm);
 114         (void)signal(SIGTTOU, SIG_IGN);
 115         (void)signal(SIGCHLD, reapchildren);
 116         for (;;) {
 117                 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
 118                 if (cc <= 0) {
 119                         if (errno != EINTR)
 120                                 sleep(1);
 121                         errno = 0;
 122                         continue;
 123                 }
 124                 if (!nutmp)             /* no one has logged in yet */
 125                         continue;
 126                 sigblock(sigmask(SIGALRM));
 127                 msgbuf[cc] = '\0';
 128                 (void)time(&lastmsgtime);
 129                 mailfor(msgbuf);
 130                 sigsetmask(0L);
 131         }
 132 }
 133
 134 void
 135 reapchildren(int signo)
 136 {
 137         while (wait3(NULL, WNOHANG, NULL) > 0);
 138 }
 139
 140 void
 141 onalrm(int signo)
 142 {
 143         static u_int utmpsize;          /* last malloced size for utmp */
 144         static u_int utmpmtime;         /* last modification time for utmp */
 145         struct stat statbf;
 146
 147         if (time(NULL) - lastmsgtime >= MAXIDLE)
 148                 exit(0);
 149         (void)alarm((u_int)15);
 150         (void)fstat(uf, &statbf);
 151         if (statbf.st_mtime > utmpmtime) {
 152                 utmpmtime = statbf.st_mtime;
 153                 if (statbf.st_size > utmpsize) {
 154                         utmpsize = statbf.st_size + 10 * sizeof(struct utmp);
 155                         if ((utmp = realloc(utmp, utmpsize)) == NULL) {
 156                                 syslog(LOG_ERR, "%s", strerror(errno));
 157                                 exit(1);
 158                         }
 159                 }
 160                 (void)lseek(uf, (off_t)0, SEEK_SET);
 161                 nutmp = read(uf, utmp, (size_t)statbf.st_size)/sizeof(struct utmp);
 162         }
 163 }
 164
 165 void
 166 mailfor(char *name)
 167 {
 168         struct utmp *utp = &utmp[nutmp];
 169         char *cp;
 170         char *file;
 171         off_t offset;
 172         int folder;
 173         char buf[sizeof(_PATH_MAILDIR) + sizeof(utmp[0].ut_name) + 1];
 174         char buf2[sizeof(_PATH_MAILDIR) + sizeof(utmp[0].ut_name) + 1];
 175
 176         if (!(cp = strchr(name, '@')))
 177                 return;
 178         *cp = '\0';
 179         offset = strtoll(cp + 1, NULL, 10);
 180         if (!(cp = strchr(cp + 1, ':')))
 181                 file = name;
 182         else
 183                 file = cp + 1;
 184         sprintf(buf, "%s/%.*s", _PATH_MAILDIR, (int)sizeof(utmp[0].ut_name),
 185             name);
 186         if (*file != '/') {
 187                 sprintf(buf2, "%s/%.*s", _PATH_MAILDIR,
 188                     (int)sizeof(utmp[0].ut_name), file);
 189                 file = buf2;
 190         }
 191         folder = strcmp(buf, file);
 192         while (--utp >= utmp)
 193                 if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name)))
 194                         notify(utp, file, offset, folder);
 195 }
 196
 197 static char *cr;
 198
 199 void
 200 notify(struct utmp *utp, char file[], off_t offset, int folder)
 201 {
 202         FILE *tp;
 203         struct stat stb;
 204         struct termios tio;
 205         char tty[20], name[sizeof(utmp[0].ut_name) + 1];
 206
 207         (void)snprintf(tty, sizeof(tty), "%s%.*s",
 208             _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line);
 209         if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) {
 210                 /* A slash is an attempt to break security... */
 211                 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty);
 212                 return;
 213         }
 214         if (stat(tty, &stb) || !(stb.st_mode & (S_IXUSR | S_IXGRP))) {
 215                 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty);
 216                 return;
 217         }
 218         dsyslog(LOG_DEBUG, "notify %s on %s\n", utp->ut_name, tty);
 219         if (fork())
 220                 return;
 221         (void)signal(SIGALRM, SIG_DFL);
 222         (void)alarm((u_int)30);
 223         if ((tp = fopen(tty, "w")) == NULL) {
 224                 dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno));
 225                 _exit(1);
 226         }
 227         (void)tcgetattr(fileno(tp), &tio);
 228         cr = ((tio.c_oflag & (OPOST|ONLCR)) == (OPOST|ONLCR)) ?  "\n" : "\n\r";
 229         (void)strncpy(name, utp->ut_name, sizeof(utp->ut_name));
 230         name[sizeof(name) - 1] = '\0';
 231         switch (stb.st_mode & (S_IXUSR | S_IXGRP)) {
 232         case S_IXUSR:
 233         case (S_IXUSR | S_IXGRP):
 234                 (void)fprintf(tp,
 235                     "%s\007New mail for %s@%.*s\007 has arrived%s%s%s:%s----%s",
 236                     cr, name, (int)sizeof(hostname), hostname,
 237                     folder ? cr : "", folder ? "to " : "", folder ? file : "",
 238                     cr, cr);
 239                 jkfprintf(tp, name, file, offset);
 240                 break;
 241         case S_IXGRP:
 242                 (void)fprintf(tp, "\007");
 243                 (void)fflush(tp);
 244                 (void)sleep(1);
 245                 (void)fprintf(tp, "\007");
 246                 break;
 247         default:
 248                 break;
 249         }
 250         (void)fclose(tp);
 251         _exit(0);
 252 }
 253
 254 void
 255 jkfprintf(FILE *tp, char user[], char file[], off_t offset)
 256 {
 257         unsigned char *cp, ch;
 258         FILE *fi;
 259         int linecnt, charcnt, inheader;
 260         struct passwd *p;
 261         unsigned char line[BUFSIZ];
 262
 263         /* Set effective uid to user in case mail drop is on nfs */
 264         if ((p = getpwnam(user)) != NULL)
 265                 (void) setuid(p->pw_uid);
 266
 267         if ((fi = fopen(file, "r")) == NULL)
 268                 return;
 269
 270         (void)fseeko(fi, offset, SEEK_CUR);
 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                             (strncmp(line, "From:", 5) &&
 287                             strncmp(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                 for (cp = line; (ch = *cp) && ch != '\n'; ++cp, --charcnt) {
 297                         /* disable upper controls and enable all other
 298                            8bit codes due to lack of locale knowledge
 299                          */
 300                         if (((ch & 0x80) && ch < 0xA0) ||
 301                             (!(ch & 0x80) && !isprint(ch) &&
 302                              !isspace(ch) && ch != '\a' && ch != '\b')
 303                            ) {
 304                                 if (ch & 0x80) {
 305                                         ch &= ~0x80;
 306                                         (void)fputs("M-", tp);
 307                                 }
 308                                 if (iscntrl(ch)) {
 309                                         ch ^= 0x40;
 310                                         (void)fputc('^', tp);
 311                                 }
 312                         }
 313                         (void)fputc(ch, tp);
 314                 }
 315                 (void)fputs(cr, tp);
 316                 --linecnt;
 317         }
 318         (void)fprintf(tp, "----%s\n", cr);
 319         (void)fclose(fi);
 320 }