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