usr/src/lib/libmail/common/notifyu.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #include "libmail.h"
  33 #include <sys/types.h>
  34 #include <sys/stat.h>
  35 #include <fcntl.h>
  36 #include <utmpx.h>
  37 #include <syslog.h>
  38 #if !defined(__cplusplus) && !defined(c_plusplus)
  39 typedef void (*SIG_PF) (int);
  40 #endif
  41 #include <unistd.h>
  42 #include <signal.h>
  43
  44 static SIG_PF catcher(void);
  45
  46 static SIG_PF catcher(void)
  47 {
  48         /* do nothing, but allow the write() to break */
  49         return (0);
  50 }
  51
  52 void
  53 notify(char *user, char *msg, int check_mesg_y, char *etcdir)
  54 {
  55         /* search the utmp file for this user */
  56         SIG_PF old;
  57         unsigned int oldalarm;
  58         struct utmpx utmpx, *putmpx = &utmpx;
  59
  60         setutxent();
  61
  62         /* grab the tty name */
  63         while ((putmpx = getutxent()) != NULL) {
  64                 if (strncmp(user, utmpx.ut_name,
  65                     sizeof (utmpx.ut_name)) == 0) {
  66                         char tty[sizeof (utmpx.ut_line)+1];
  67                         char dev[MAXFILENAME];
  68                         FILE *port;
  69                         size_t i;
  70                         int fd;
  71
  72                         for (i = 0; i < sizeof (utmpx.ut_line); i++)
  73                                 tty[i] = utmpx.ut_line[i];
  74                         tty[i] = '\0';
  75
  76                         /* stick /dev/ in front */
  77                         (void) sprintf(dev, "%s/dev/%s", etcdir, tty);
  78
  79                         /* break out if write() to the tty hangs */
  80                         old = (SIG_PF)signal(SIGALRM, (SIG_PF)catcher);
  81                         oldalarm = alarm(300);
  82
  83                         /* check if device is really a tty */
  84                         if ((fd = open(dev, O_WRONLY|O_NOCTTY)) == -1) {
  85                                 (void) fprintf(stderr,
  86                                     "Cannot open %s.\n", dev);
  87                                 continue;
  88                         } else {
  89                                 if (!isatty(fd)) {
  90                                         (void) fprintf(stderr, "%s in utmpx is "
  91                                             "not a tty\n", tty);
  92                                         openlog("mail", 0, LOG_AUTH);
  93                                         syslog(LOG_CRIT, "%s in utmp is "
  94                                             "not a tty\n", tty);
  95                                         closelog();
  96                                         (void) close(fd);
  97                                         continue;
  98                                 }
  99                         }
 100                         (void) close(fd);
 101
 102                         /* write to the tty */
 103                         port = fopen(dev, "w");
 104                         if (port != 0) {
 105                                 (void) fprintf(port, "\r\n%s\r\n", msg);
 106                                 (void) fclose(port);
 107                         }
 108
 109                         /* clean up our alarm */
 110                         (void) alarm(0);
 111                         (void) signal(SIGALRM, old);
 112                         (void) alarm(oldalarm);
 113                 }
 114         }
 115         endutxent();
 116 }