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  * @(#)comsat.c 8.1 (Berkeley) 6/4/93
  34  * $FreeBSD: src/libexec/comsat/comsat.c,v 1.17 2005/02/14 17:42:56 stefanf Exp $
  35  * $DragonFly: src/libexec/comsat/comsat.c,v 1.6 2005/05/03 17:39:03 liamfoy Exp $
  36  */
  37
  38 #include <sys/param.h>
  39 #include <sys/socket.h>
  40 #include <sys/stat.h>
  41 #include <sys/file.h>
  42 #include <sys/wait.h>
  43
  44 #include <netinet/in.h>
  45
  46 #include <ctype.h>
  47 #include <err.h>
  48 #include <errno.h>
  49 #include <netdb.h>
  50 #include <paths.h>
  51 #include <pwd.h>
  52 #include <termios.h>
  53 #include <signal.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include <sysexits.h>
  58 #include <syslog.h>
  59 #include <unistd.h>
  60 #include <utmp.h>
  61
  62 int     debug = 0;
  63 #define dsyslog if (debug) syslog
  64
  65 #define MAXIDLE 120
  66
  67 char    hostname[MAXHOSTNAMELEN];
  68 struct  utmp *utmp = NULL;
  69 time_t  lastmsgtime;
  70 int     nutmp, uf;
  71
  72 void jkfprintf (FILE *, const char *, const char *, off_t);
  73 void mailfor (char *);
  74 void notify (struct utmp *, char *, off_t, int);
  75 void onalrm (int);
  76 void reapchildren (int);
  77
  78 int
  79 main(int argc __unused, char **argv __unused)
  80 {
  81         struct sockaddr_in from;
  82         socklen_t fromlen;
  83         int cc;
  84         char msgbuf[256];
  85
  86         /* verify proper invocation */
  87         fromlen = sizeof(from);
  88         if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0)
  89                 err(1, "getsockname");
  90         openlog("comsat", LOG_PID, LOG_DAEMON);
  91         if (chdir(_PATH_MAILDIR)) {
  92                 syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR);
  93                 recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
  94                 exit(1);
  95         }
  96         if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) {
  97                 syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP);
  98                 recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
  99                 exit(1);
 100         }
 101         time(&lastmsgtime);
 102         gethostname(hostname, sizeof(hostname));
 103         onalrm(0);
 104         signal(SIGALRM, onalrm);
 105         signal(SIGTTOU, SIG_IGN);
 106         signal(SIGCHLD, reapchildren);
 107         for (;;) {
 108                 cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
 109                 if (cc <= 0) {
 110                         if (errno != EINTR)
 111                                 sleep(1);
 112                         errno = 0;
 113                         continue;
 114                 }
 115                 if (!nutmp)             /* no one has logged in yet */
 116                         continue;
 117                 sigblock(sigmask(SIGALRM));
 118                 msgbuf[cc] = '\0';
 119                 time(&lastmsgtime);
 120                 mailfor(msgbuf);
 121                 sigsetmask(0L);
 122         }
 123 }
 124
 125 void
 126 reapchildren(int signo __unused)
 127 {
 128         while (wait3(NULL, WNOHANG, NULL) > 0);
 129 }
 130
 131 void
 132 onalrm(int signo __unused)
 133 {
 134         static u_int utmpsize;          /* last malloced size for utmp */
 135         static time_t utmpmtime;        /* last modification time for utmp */
 136         struct stat statbf;
 137
 138         if (time(NULL) - lastmsgtime >= MAXIDLE)
 139                 exit(EX_OK);
 140         alarm((u_int)15);
 141         fstat(uf, &statbf);
 142         if (statbf.st_mtime > utmpmtime) {
 143                 utmpmtime = statbf.st_mtime;
 144                 if (statbf.st_size > utmpsize) {
 145                         utmpsize = statbf.st_size + 10 * sizeof(struct utmp);
 146                         if ((utmp = realloc(utmp, utmpsize)) == NULL) {
 147                                 syslog(LOG_ERR, "realloc: %m");
 148                                 exit(1);
 149                         }
 150                 }
 151                 lseek(uf, (off_t)0, SEEK_SET);
 152                 nutmp = read(uf, utmp, (size_t)statbf.st_size)/sizeof(struct utmp);
 153         }
 154 }
 155
 156 void
 157 mailfor(char *name)
 158 {
 159         struct utmp *utp = &utmp[nutmp];
 160         char *cp;
 161         char *file;
 162         off_t offset;
 163         int folder;
 164         char buf[sizeof(_PATH_MAILDIR) + sizeof(utmp[0].ut_name) + 1];
 165         char buf2[sizeof(_PATH_MAILDIR) + sizeof(utmp[0].ut_name) + 1];
 166
 167         if (!(cp = strchr(name, '@')))
 168                 return;
 169         *cp = '\0';
 170         offset = strtoll(cp + 1, NULL, 10);
 171         if (!(cp = strchr(cp + 1, ':')))
 172                 file = name;
 173         else
 174                 file = cp + 1;
 175         sprintf(buf, "%s/%.*s", _PATH_MAILDIR, (int)sizeof(utmp[0].ut_name),
 176             name);
 177         if (*file != '/') {
 178                 sprintf(buf2, "%s/%.*s", _PATH_MAILDIR,
 179                     (int)sizeof(utmp[0].ut_name), file);
 180                 file = buf2;
 181         }
 182         folder = strcmp(buf, file);
 183         while (--utp >= utmp)
 184                 if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name)))
 185                         notify(utp, file, offset, folder);
 186 }
 187
 188 static const char *cr;
 189
 190 void
 191 notify(struct utmp *utp, char *file, off_t offset, int folder)
 192 {
 193         FILE *tp;
 194         struct stat stb;
 195         struct termios tio;
 196         char tty[20], name[sizeof(utmp[0].ut_name) + 1];
 197
 198         snprintf(tty, sizeof(tty), "%s%.*s",
 199             _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line);
 200         if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) {
 201                 /* A slash is an attempt to break security... */
 202                 syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty);
 203                 return;
 204         }
 205         if (stat(tty, &stb) || !(stb.st_mode & (S_IXUSR | S_IXGRP))) {
 206                 dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty);
 207                 return;
 208         }
 209         dsyslog(LOG_DEBUG, "notify %s on %s\n", utp->ut_name, tty);
 210         if (fork())
 211                 return;
 212         signal(SIGALRM, SIG_DFL);
 213         alarm((u_int)30);
 214         if ((tp = fopen(tty, "w")) == NULL) {
 215                 dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno));
 216                 _exit(1);
 217         }
 218         tcgetattr(fileno(tp), &tio);
 219         cr = ((tio.c_oflag & (OPOST|ONLCR)) == (OPOST|ONLCR)) ?  "\n" : "\n\r";
 220         strncpy(name, utp->ut_name, sizeof(utp->ut_name));
 221         name[sizeof(name) - 1] = '\0';
 222         switch (stb.st_mode & (S_IXUSR | S_IXGRP)) {
 223         case S_IXUSR:
 224         case (S_IXUSR | S_IXGRP):
 225                 fprintf(tp,
 226                     "%s\007New mail for %s@%.*s\007 has arrived%s%s%s:%s----%s",
 227                     cr, name, (int)sizeof(hostname), hostname,
 228                     folder ? cr : "", folder ? "to " : "", folder ? file : "",
 229                     cr, cr);
 230                 jkfprintf(tp, name, file, offset);
 231                 break;
 232         case S_IXGRP:
 233                 fprintf(tp, "\007");
 234                 fflush(tp);
 235                 sleep(1);
 236                 fprintf(tp, "\007");
 237                 break;
 238         default:
 239                 break;
 240         }
 241         fclose(tp);
 242         _exit(EX_OK);
 243 }
 244
 245 void
 246 jkfprintf(FILE *tp, const char *user, const char *file, off_t offset)
 247 {
 248         unsigned char *cp, ch;
 249         FILE *fi;
 250         int linecnt, charcnt, inheader;
 251         struct passwd *p;
 252         unsigned char line[BUFSIZ];
 253
 254         /* Set effective uid to user in case mail drop is on nfs */
 255         if ((p = getpwnam(user)) != NULL)
 256                 setuid(p->pw_uid);
 257
 258         if ((fi = fopen(file, "r")) == NULL)
 259                 return;
 260
 261         fseeko(fi, offset, SEEK_SET);
 262         /*
 263          * Print the first 7 lines or 560 characters of the new mail
 264          * (whichever comes first).  Skip header crap other than
 265          * From, Subject, To, and Date.
 266          */
 267         linecnt = 7;
 268         charcnt = 560;
 269         inheader = 1;
 270         while (fgets(line, sizeof(line), fi) != NULL) {
 271                 if (inheader) {
 272                         if (line[0] == '\n') {
 273                                 inheader = 0;
 274                                 continue;
 275                         }
 276                         if (line[0] == ' ' || line[0] == '\t' ||
 277                             (strncmp(line, "From:", 5) &&
 278                             strncmp(line, "Subject:", 8)))
 279                                 continue;
 280                 }
 281                 if (linecnt <= 0 || charcnt <= 0) {
 282                         fprintf(tp, "...more...%s", cr);
 283                         fclose(fi);
 284                         return;
 285                 }
 286                 /* strip weird stuff so can't trojan horse stupid terminals */
 287                 for (cp = line; (ch = *cp) && ch != '\n'; ++cp, --charcnt) {
 288                         /* disable upper controls and enable all other
 289                            8bit codes due to lack of locale knowledge
 290                          */
 291                         if (((ch & 0x80) && ch < 0xA0) ||
 292                             (!(ch & 0x80) && !isprint(ch) &&
 293                              !isspace(ch) && ch != '\a' && ch != '\b')
 294                            ) {
 295                                 if (ch & 0x80) {
 296                                         ch &= ~0x80;
 297                                         fputs("M-", tp);
 298                                 }
 299                                 if (iscntrl(ch)) {
 300                                         ch ^= 0x40;
 301                                         fputc('^', tp);
 302                                 }
 303                         }
 304                         fputc(ch, tp);
 305                 }
 306                 fputs(cr, tp);
 307                 --linecnt;
 308         }
 309         fprintf(tp, "----%s\n", cr);
 310         fclose(fi);
 311 }