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  * @(#) Copyright (c) 1980, 1993 The Regents of the University of California.  All rights reserved.
  34  * @(#)comsat.c 8.1 (Berkeley) 6/4/93
  35  * $FreeBSD: src/libexec/comsat/comsat.c,v 1.13.2.1 2002/08/09 02:56:30 johan Exp $
  36  * $DragonFly: src/libexec/comsat/comsat.c,v 1.6 2005/05/03 17:39:03 liamfoy Exp $
  37  */
  38
  39 #include <sys/param.h>
  40 #include <sys/socket.h>
  41 #include <sys/stat.h>
  42 #include <sys/file.h>
  43 #include <sys/wait.h>
  44
  45 #include <netinet/in.h>
  46
  47 #include <ctype.h>
  48 #include <err.h>
  49 #include <errno.h>
  50 #include <netdb.h>
  51 #include <paths.h>
  52 #include <pwd.h>
  53 #include <termios.h>
  54 #include <signal.h>
  55 #include <stdio.h>
  56 #include <stdlib.h>
  57 #include <string.h>
  58 #include <sysexits.h>
  59 #include <syslog.h>
  60 #include <unistd.h>
  61 #include <utmp.h>
  62
  63 int     debug = 0;
  64 #define dsyslog if (debug) syslog
  65
  66 #define MAXIDLE 120
  67
  68 char    hostname[MAXHOSTNAMELEN];
  69 struct  utmp *utmp = NULL;
  70 time_t  lastmsgtime;
  71 int     nutmp, uf;
  72
  73 void jkfprintf (FILE *, const char *, const char *, off_t);
  74 void mailfor (char *);
  75 void notify (struct utmp *, char *, off_t, int);
  76 void onalrm (int);
  77 void reapchildren (int);
  78
  79 int
  80 main(int argc __unused, char **argv __unused)
  81 {
  82         struct sockaddr_in from;
  83         socklen_t fromlen;
  84         int cc;
  85         char msgbuf[256];
  86
  87         /* verify proper invocation */
  88         fromlen = sizeof(from);
  89         if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0)
  90                 err(1, "getsockname");
  91         openlog("comsat", LOG_PID, LOG_DAEMON);
  92         if (chdir(_PATH_MAILDIR)) {
  93                 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR);
  94                 recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
  95                 exit(1);
  96         }
  97         if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) {
  98                 syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP);
  99                 recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
 100                 exit(1);
 101         }
 102         time(&lastmsgtime);
 103         gethostname(hostname, sizeof(hostname));
 104         onalrm(0);
 105         signal(SIGALRM, onalrm);
 106         signal(SIGTTOU, SIG_IGN);
 107         signal(SIGCHLD, reapchildren);
 108         for (;;) {
 109                 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
 110                 if (cc <= 0) {
 111                         if (errno != EINTR)
 112                                 sleep(1);
 113                         errno = 0;
 114                         continue;
 115                 }
 116                 if (!nutmp)             /* no one has logged in yet */
 117                         continue;
 118                 sigblock(sigmask(SIGALRM));
 119                 msgbuf[cc] = '\0';
 120                 time(&lastmsgtime);
 121                 mailfor(msgbuf);
 122                 sigsetmask(0L);
 123         }
 124 }
 125
 126 void
 127 reapchildren(int signo __unused)
 128 {
 129         while (wait3(NULL, WNOHANG, NULL) > 0);
 130 }
 131
 132 void
 133 onalrm(int signo __unused)
 134 {
 135         static u_int utmpsize;          /* last malloced size for utmp */
 136         static time_t utmpmtime;        /* last modification time for utmp */
 137         struct stat statbf;
 138
 139         if (time(NULL) - lastmsgtime >= MAXIDLE)
 140                 exit(EX_OK);
 141         alarm((u_int)15);
 142         fstat(uf, &statbf);
 143         if (statbf.st_mtime > utmpmtime) {
 144                 utmpmtime = statbf.st_mtime;
 145                 if (statbf.st_size > utmpsize) {
 146                         utmpsize = statbf.st_size + 10 * sizeof(struct utmp);
 147                         if ((utmp = realloc(utmp, utmpsize)) == NULL) {
 148                                 syslog(LOG_ERR, "realloc: %m");
 149                                 exit(1);
 150                         }
 151                 }
 152                 lseek(uf, (off_t)0, L_SET);
 153                 nutmp = read(uf, utmp, (int)statbf.st_size)/sizeof(struct utmp);
 154         }
 155 }
 156
 157 void
 158 mailfor(char *name)
 159 {
 160         struct utmp *utp = &utmp[nutmp];
 161         char *cp;
 162         char *file;
 163         off_t offset;
 164         int folder;
 165         char buf[sizeof(_PATH_MAILDIR) + sizeof(utmp[0].ut_name) + 1];
 166         char buf2[sizeof(_PATH_MAILDIR) + sizeof(utmp[0].ut_name) + 1];
 167
 168         if (!(cp = strchr(name, '@')))
 169                 return;
 170         *cp = '\0';
 171         offset = atoi(cp + 1);
 172         if (!(cp = strchr(cp + 1, ':')))
 173                 file = name;
 174         else
 175                 file = cp + 1;
 176         sprintf(buf, "%s/%.*s", _PATH_MAILDIR, (int)sizeof(utmp[0].ut_name),
 177             name);
 178         if (*file != '/') {
 179                 sprintf(buf2, "%s/%.*s", _PATH_MAILDIR,
 180                     (int)sizeof(utmp[0].ut_name), file);
 181                 file = buf2;
 182         }
 183         folder = strcmp(buf, file);
 184         while (--utp >= utmp)
 185                 if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name)))
 186                         notify(utp, file, offset, folder);
 187 }
 188
 189 static const char *cr;
 190
 191 void
 192 notify(struct utmp *utp, char *file, off_t offset, int folder)
 193 {
 194         FILE *tp;
 195         struct stat stb;
 196         struct termios tio;
 197         char tty[20], name[sizeof(utmp[0].ut_name) + 1];
 198
 199         snprintf(tty, sizeof(tty), "%s%.*s",
 200             _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line);
 201         if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) {
 202                 /* A slash is an attempt to break security... */
 203                 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty);
 204                 return;
 205         }
 206         if (stat(tty, &stb) || !(stb.st_mode & (S_IXUSR | S_IXGRP))) {
 207                 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty);
 208                 return;
 209         }
 210         dsyslog(LOG_DEBUG, "notify %s on %s\n", utp->ut_name, tty);
 211         if (fork())
 212                 return;
 213         signal(SIGALRM, SIG_DFL);
 214         alarm((u_int)30);
 215         if ((tp = fopen(tty, "w")) == NULL) {
 216                 dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno));
 217                 _exit(1);
 218         }
 219         tcgetattr(fileno(tp), &tio);
 220         cr = ((tio.c_oflag & (OPOST|ONLCR)) == (OPOST|ONLCR)) ?  "\n" : "\n\r";
 221         strncpy(name, utp->ut_name, sizeof(utp->ut_name));
 222         name[sizeof(name) - 1] = '\0';
 223         switch (stb.st_mode & (S_IXUSR | S_IXGRP)) {
 224         case S_IXUSR:
 225         case (S_IXUSR | S_IXGRP):
 226                 fprintf(tp,
 227                     "%s\007New mail for %s@%.*s\007 has arrived%s%s%s:%s----%s",
 228                     cr, name, (int)sizeof(hostname), hostname,
 229                     folder ? cr : "", folder ? "to " : "", folder ? file : "",
 230                     cr, cr);
 231                 jkfprintf(tp, name, file, offset);
 232                 break;
 233         case S_IXGRP:
 234                 fprintf(tp, "\007");
 235                 fflush(tp);
 236                 sleep(1);
 237                 fprintf(tp, "\007");
 238                 break;
 239         default:
 240                 break;
 241         }
 242         fclose(tp);
 243         _exit(EX_OK);
 244 }
 245
 246 void
 247 jkfprintf(FILE *tp, const char *user, const char *file, off_t offset)
 248 {
 249         unsigned char *cp, ch;
 250         FILE *fi;
 251         int linecnt, charcnt, inheader;
 252         struct passwd *p;
 253         unsigned char line[BUFSIZ];
 254
 255         /* Set effective uid to user in case mail drop is on nfs */
 256         if ((p = getpwnam(user)) != NULL)
 257                 setuid(p->pw_uid);
 258
 259         if ((fi = fopen(file, "r")) == NULL)
 260                 return;
 261
 262         fseek(fi, offset, L_SET);
 263         /*
 264          * Print the first 7 lines or 560 characters of the new mail
 265          * (whichever comes first).  Skip header crap other than
 266          * From, Subject, To, and Date.
 267          */
 268         linecnt = 7;
 269         charcnt = 560;
 270         inheader = 1;
 271         while (fgets(line, sizeof(line), fi) != NULL) {
 272                 if (inheader) {
 273                         if (line[0] == '\n') {
 274                                 inheader = 0;
 275                                 continue;
 276                         }
 277                         if (line[0] == ' ' || line[0] == '\t' ||
 278                             (strncmp(line, "From:", 5) &&
 279                             strncmp(line, "Subject:", 8)))
 280                                 continue;
 281                 }
 282                 if (linecnt <= 0 || charcnt <= 0) {
 283                         fprintf(tp, "...more...%s", cr);
 284                         fclose(fi);
 285                         return;
 286                 }
 287                 /* strip weird stuff so can't trojan horse stupid terminals */
 288                 for (cp = line; (ch = *cp) && ch != '\n'; ++cp, --charcnt) {
 289                         /* disable upper controls and enable all other
 290                            8bit codes due to lack of locale knowledge
 291                          */
 292                         if (((ch & 0x80) && ch < 0xA0) ||
 293                             (!(ch & 0x80) && !isprint(ch) &&
 294                              !isspace(ch) && ch != '\a' && ch != '\b')
 295                            ) {
 296                                 if (ch & 0x80) {
 297                                         ch &= ~0x80;
 298                                         fputs("M-", tp);
 299                                 }
 300                                 if (iscntrl(ch)) {
 301                                         ch ^= 0x40;
 302                                         fputc('^', tp);
 303                                 }
 304                         }
 305                         fputc(ch, tp);
 306                 }
 307                 fputs(cr, tp);
 308                 --linecnt;
 309         }
 310         fprintf(tp, "----%s\n", cr);
 311         fclose(fi);
 312 }