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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)comsat.c 8.1 (Berkeley) 6/4/93
  30  * $FreeBSD: src/libexec/comsat/comsat.c,v 1.17 2005/02/14 17:42:56 stefanf Exp $
  31  * $DragonFly: src/libexec/comsat/comsat.c,v 1.6 2005/05/03 17:39:03 liamfoy Exp $
  32  */
  33
  34 #include <sys/param.h>
  35 #include <sys/socket.h>
  36 #include <sys/stat.h>
  37 #include <sys/file.h>
  38 #include <sys/wait.h>
  39
  40 #include <netinet/in.h>
  41
  42 #include <ctype.h>
  43 #include <err.h>
  44 #include <errno.h>
  45 #include <netdb.h>
  46 #include <paths.h>
  47 #include <pwd.h>
  48 #include <termios.h>
  49 #include <signal.h>
  50 #include <stdio.h>
  51 #include <stdlib.h>
  52 #include <string.h>
  53 #include <sysexits.h>
  54 #include <syslog.h>
  55 #include <unistd.h>
  56 #include <utmp.h>
  57
  58 int     debug = 0;
  59 #define dsyslog if (debug) syslog
  60
  61 #define MAXIDLE 120
  62
  63 char    hostname[MAXHOSTNAMELEN];
  64 struct  utmp *utmp = NULL;
  65 time_t  lastmsgtime;
  66 int     nutmp, uf;
  67
  68 void jkfprintf (FILE *, const char *, const char *, off_t);
  69 void mailfor (char *);
  70 void notify (struct utmp *, char *, off_t, int);
  71 void onalrm (int);
  72 void reapchildren (int);
  73
  74 int
  75 main(int argc __unused, char **argv __unused)
  76 {
  77         struct sockaddr_in from;
  78         socklen_t fromlen;
  79         int cc;
  80         char msgbuf[256];
  81
  82         /* verify proper invocation */
  83         fromlen = sizeof(from);
  84         if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0)
  85                 err(1, "getsockname");
  86         openlog("comsat", LOG_PID, LOG_DAEMON);
  87         if (chdir(_PATH_MAILDIR)) {
  88                 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR);
  89                 recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
  90                 exit(1);
  91         }
  92         if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) {
  93                 syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP);
  94                 recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
  95                 exit(1);
  96         }
  97         time(&lastmsgtime);
  98         gethostname(hostname, sizeof(hostname));
  99         onalrm(0);
 100         signal(SIGALRM, onalrm);
 101         signal(SIGTTOU, SIG_IGN);
 102         signal(SIGCHLD, reapchildren);
 103         for (;;) {
 104                 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
 105                 if (cc <= 0) {
 106                         if (errno != EINTR)
 107                                 sleep(1);
 108                         errno = 0;
 109                         continue;
 110                 }
 111                 if (!nutmp)             /* no one has logged in yet */
 112                         continue;
 113                 sigblock(sigmask(SIGALRM));
 114                 msgbuf[cc] = '\0';
 115                 time(&lastmsgtime);
 116                 mailfor(msgbuf);
 117                 sigsetmask(0L);
 118         }
 119 }
 120
 121 void
 122 reapchildren(int signo __unused)
 123 {
 124         while (wait3(NULL, WNOHANG, NULL) > 0);
 125 }
 126
 127 void
 128 onalrm(int signo __unused)
 129 {
 130         static u_int utmpsize;          /* last malloced size for utmp */
 131         static time_t utmpmtime;        /* last modification time for utmp */
 132         struct stat statbf;
 133
 134         if (time(NULL) - lastmsgtime >= MAXIDLE)
 135                 exit(EX_OK);
 136         alarm((u_int)15);
 137         fstat(uf, &statbf);
 138         if (statbf.st_mtime > utmpmtime) {
 139                 utmpmtime = statbf.st_mtime;
 140                 if (statbf.st_size > utmpsize) {
 141                         utmpsize = statbf.st_size + 10 * sizeof(struct utmp);
 142                         if ((utmp = realloc(utmp, utmpsize)) == NULL) {
 143                                 syslog(LOG_ERR, "realloc: %m");
 144                                 exit(1);
 145                         }
 146                 }
 147                 lseek(uf, (off_t)0, SEEK_SET);
 148                 nutmp = read(uf, utmp, (size_t)statbf.st_size)/sizeof(struct utmp);
 149         }
 150 }
 151
 152 void
 153 mailfor(char *name)
 154 {
 155         struct utmp *utp = &utmp[nutmp];
 156         char *cp;
 157         char *file;
 158         off_t offset;
 159         int folder;
 160         char buf[sizeof(_PATH_MAILDIR) + sizeof(utmp[0].ut_name) + 1];
 161         char buf2[sizeof(_PATH_MAILDIR) + sizeof(utmp[0].ut_name) + 1];
 162
 163         if (!(cp = strchr(name, '@')))
 164                 return;
 165         *cp = '\0';
 166         offset = strtoll(cp + 1, NULL, 10);
 167         if (!(cp = strchr(cp + 1, ':')))
 168                 file = name;
 169         else
 170                 file = cp + 1;
 171         sprintf(buf, "%s/%.*s", _PATH_MAILDIR, (int)sizeof(utmp[0].ut_name),
 172             name);
 173         if (*file != '/') {
 174                 sprintf(buf2, "%s/%.*s", _PATH_MAILDIR,
 175                     (int)sizeof(utmp[0].ut_name), file);
 176                 file = buf2;
 177         }
 178         folder = strcmp(buf, file);
 179         while (--utp >= utmp)
 180                 if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name)))
 181                         notify(utp, file, offset, folder);
 182 }
 183
 184 static const char *cr;
 185
 186 void
 187 notify(struct utmp *utp, char *file, off_t offset, int folder)
 188 {
 189         FILE *tp;
 190         struct stat stb;
 191         struct termios tio;
 192         char tty[20], name[sizeof(utmp[0].ut_name) + 1];
 193
 194         snprintf(tty, sizeof(tty), "%s%.*s",
 195             _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line);
 196         if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) {
 197                 /* A slash is an attempt to break security... */
 198                 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty);
 199                 return;
 200         }
 201         if (stat(tty, &stb) || !(stb.st_mode & (S_IXUSR | S_IXGRP))) {
 202                 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty);
 203                 return;
 204         }
 205         dsyslog(LOG_DEBUG, "notify %s on %s\n", utp->ut_name, tty);
 206         if (fork())
 207                 return;
 208         signal(SIGALRM, SIG_DFL);
 209         alarm((u_int)30);
 210         if ((tp = fopen(tty, "w")) == NULL) {
 211                 dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno));
 212                 _exit(1);
 213         }
 214         tcgetattr(fileno(tp), &tio);
 215         cr = ((tio.c_oflag & (OPOST|ONLCR)) == (OPOST|ONLCR)) ?  "\n" : "\n\r";
 216         strncpy(name, utp->ut_name, sizeof(utp->ut_name));
 217         name[sizeof(name) - 1] = '\0';
 218         switch (stb.st_mode & (S_IXUSR | S_IXGRP)) {
 219         case S_IXUSR:
 220         case (S_IXUSR | S_IXGRP):
 221                 fprintf(tp,
 222                     "%s\007New mail for %s@%.*s\007 has arrived%s%s%s:%s----%s",
 223                     cr, name, (int)sizeof(hostname), hostname,
 224                     folder ? cr : "", folder ? "to " : "", folder ? file : "",
 225                     cr, cr);
 226                 jkfprintf(tp, name, file, offset);
 227                 break;
 228         case S_IXGRP:
 229                 fprintf(tp, "\007");
 230                 fflush(tp);
 231                 sleep(1);
 232                 fprintf(tp, "\007");
 233                 break;
 234         default:
 235                 break;
 236         }
 237         fclose(tp);
 238         _exit(EX_OK);
 239 }
 240
 241 void
 242 jkfprintf(FILE *tp, const char *user, const char *file, off_t offset)
 243 {
 244         unsigned char *cp, ch;
 245         FILE *fi;
 246         int linecnt, charcnt, inheader;
 247         struct passwd *p;
 248         unsigned char line[BUFSIZ];
 249
 250         /* Set effective uid to user in case mail drop is on nfs */
 251         if ((p = getpwnam(user)) != NULL)
 252                 setuid(p->pw_uid);
 253
 254         if ((fi = fopen(file, "r")) == NULL)
 255                 return;
 256
 257         fseeko(fi, offset, SEEK_SET);
 258         /*
 259          * Print the first 7 lines or 560 characters of the new mail
 260          * (whichever comes first).  Skip header crap other than
 261          * From, Subject, To, and Date.
 262          */
 263         linecnt = 7;
 264         charcnt = 560;
 265         inheader = 1;
 266         while (fgets(line, sizeof(line), fi) != NULL) {
 267                 if (inheader) {
 268                         if (line[0] == '\n') {
 269                                 inheader = 0;
 270                                 continue;
 271                         }
 272                         if (line[0] == ' ' || line[0] == '\t' ||
 273                             (strncmp(line, "From:", 5) &&
 274                             strncmp(line, "Subject:", 8)))
 275                                 continue;
 276                 }
 277                 if (linecnt <= 0 || charcnt <= 0) {
 278                         fprintf(tp, "...more...%s", cr);
 279                         fclose(fi);
 280                         return;
 281                 }
 282                 /* strip weird stuff so can't trojan horse stupid terminals */
 283                 for (cp = line; (ch = *cp) && ch != '\n'; ++cp, --charcnt) {
 284                         /* disable upper controls and enable all other
 285                            8bit codes due to lack of locale knowledge
 286                          */
 287                         if (((ch & 0x80) && ch < 0xA0) ||
 288                             (!(ch & 0x80) && !isprint(ch) &&
 289                              !isspace(ch) && ch != '\a' && ch != '\b')
 290                            ) {
 291                                 if (ch & 0x80) {
 292                                         ch &= ~0x80;
 293                                         fputs("M-", tp);
 294                                 }
 295                                 if (iscntrl(ch)) {
 296                                         ch ^= 0x40;
 297                                         fputc('^', tp);
 298                                 }
 299                         }
 300                         fputc(ch, tp);
 301                 }
 302                 fputs(cr, tp);
 303                 --linecnt;
 304         }
 305         fprintf(tp, "----%s\n", cr);
 306         fclose(fi);
 307 }