333 lines
8.7 KiB
C
333 lines
8.7 KiB
C
/* $NetBSD: comsat.c,v 1.39 2009/03/14 11:43:24 lukem Exp $ */
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/*
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* Copyright (c) 1980, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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__COPYRIGHT("@(#) Copyright (c) 1980, 1993\
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The Regents of the University of California. All rights reserved.");
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#if 0
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static char sccsid[] = "from: @(#)comsat.c 8.1 (Berkeley) 6/4/93";
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#else
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__RCSID("$NetBSD: comsat.c,v 1.39 2009/03/14 11:43:24 lukem Exp $");
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#endif
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#endif /* not lint */
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/file.h>
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#include <sys/wait.h>
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#include <netinet/in.h>
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#include <errno.h>
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#include <netdb.h>
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#include <paths.h>
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#include <pwd.h>
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#include <err.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syslog.h>
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#include <termios.h>
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#include <time.h>
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#include <vis.h>
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#include <unistd.h>
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#ifdef SUPPORT_UTMP
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#include <utmp.h>
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#endif
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#ifdef SUPPORT_UTMPX
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#include <utmpx.h>
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#endif
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#include "utmpentry.h"
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#if !defined(SUPPORT_UTMP) && !defined(SUPPORT_UTMPX)
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#error "SUPPORT_UTMP and/or SUPPORT_UTMPX must be defined"
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#endif
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#define dsyslog if (debug) syslog
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#define MAXIDLE 120
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static int logging;
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static int debug;
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static char hostname[MAXHOSTNAMELEN + 1];
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static int nutmp;
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static struct utmpentry *utmp = NULL;
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static time_t lastmsgtime;
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static volatile sig_atomic_t needupdate;
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int main(int, char *[]);
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static void jkfprintf(FILE *, const char *, off_t, const char *);
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static void mailfor(const char *);
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static void notify(const struct utmpentry *, off_t);
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static void onalrm(int);
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static void checkutmp(void);
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int
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main(int argc, char *argv[])
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{
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struct sockaddr_storage from;
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int cc, ch;
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socklen_t fromlen;
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char msgbuf[100];
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sigset_t nsigset, osigset;
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/* verify proper invocation */
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fromlen = sizeof(from);
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if (getsockname(0, (struct sockaddr *)(void *)&from, &fromlen) == -1)
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err(1, "getsockname");
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openlog("comsat", LOG_PID, LOG_DAEMON);
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while ((ch = getopt(argc, argv, "l")) != -1)
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switch (ch) {
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case 'l':
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logging = 1;
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break;
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default:
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syslog(LOG_ERR, "Usage: %s [-l]", getprogname());
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exit(1);
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}
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if (chdir(_PATH_MAILDIR) == -1) {
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syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR);
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(void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
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exit(1);
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}
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(void)time(&lastmsgtime);
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(void)gethostname(hostname, sizeof(hostname));
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hostname[sizeof(hostname) - 1] = '\0';
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(void)signal(SIGALRM, onalrm);
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(void)signal(SIGTTOU, SIG_IGN);
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(void)signal(SIGCHLD, SIG_IGN);
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(void)sigemptyset(&nsigset);
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(void)sigaddset(&nsigset, SIGALRM);
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if (sigprocmask(SIG_SETMASK, NULL, &osigset) == -1) {
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syslog(LOG_ERR, "sigprocmask get failed (%m)");
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exit(1);
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}
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needupdate = 1;
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for (;;) {
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cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0);
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if (cc <= 0) {
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if (errno != EINTR)
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sleep(1);
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errno = 0;
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checkutmp();
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continue;
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} else
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checkutmp();
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if (!nutmp) /* no one has logged in yet */
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continue;
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if (sigprocmask(SIG_SETMASK, &nsigset, NULL) == -1) {
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syslog(LOG_ERR, "sigprocmask set failed (%m)");
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exit(1);
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}
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msgbuf[cc] = '\0';
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(void)time(&lastmsgtime);
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mailfor(msgbuf);
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if (sigprocmask(SIG_SETMASK, &osigset, NULL) == -1) {
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syslog(LOG_ERR, "sigprocmask restore failed (%m)");
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exit(1);
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}
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}
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}
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static void
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/*ARGSUSED*/
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onalrm(int signo)
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{
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needupdate = 1;
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}
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static void
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checkutmp(void)
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{
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if (!needupdate)
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return;
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needupdate = 0;
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if (time(NULL) - lastmsgtime >= MAXIDLE)
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exit(0);
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(void)alarm((u_int)15);
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nutmp = getutentries(NULL, &utmp);
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}
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static void
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mailfor(const char *name)
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{
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struct utmpentry *ep;
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char *cp, *fn;
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off_t offset;
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intmax_t val;
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if (!(cp = strchr(name, '@')))
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return;
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*cp = '\0';
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errno = 0;
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offset = val = strtoimax(cp + 1, &fn, 10);
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if (errno == ERANGE || offset != val)
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return;
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if (fn && *fn && *fn != '\n') {
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/*
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* Procmail sends messages to comsat with a trailing colon
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* and a pathname to the folder where the new message was
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* deposited. Since we can't reliably open only regular
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* files, we need to ignore these. With one exception:
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* if it mentions the user's system mailbox.
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*/
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char maildir[MAXPATHLEN];
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int l = snprintf(maildir, sizeof(maildir), ":%s/%s",
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_PATH_MAILDIR, name);
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if (l >= (int)sizeof(maildir) || strcmp(maildir, fn) != 0)
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return;
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}
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for (ep = utmp; ep != NULL; ep = ep->next)
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if (strcmp(ep->name, name) == 0)
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notify(ep, offset);
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}
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static void
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notify(const struct utmpentry *ep, off_t offset)
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{
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FILE *tp;
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struct passwd *p;
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struct stat stb;
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struct termios ttybuf;
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char tty[sizeof(_PATH_DEV) + sizeof(ep->line) + 1];
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const char *cr = ep->line;
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if (strncmp(cr, "pts/", 4) == 0)
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cr += 4;
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if (strchr(cr, '/')) {
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/* A slash is an attempt to break security... */
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syslog(LOG_AUTH | LOG_NOTICE, "Unexpected `/' in `%s'",
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ep->line);
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return;
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}
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(void)snprintf(tty, sizeof(tty), "%s%s", _PATH_DEV, ep->line);
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if (stat(tty, &stb) == -1 || !(stb.st_mode & S_IEXEC)) {
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dsyslog(LOG_DEBUG, "%s: wrong mode on %s", ep->name, tty);
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return;
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}
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dsyslog(LOG_DEBUG, "notify %s on %s", ep->name, tty);
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switch (fork()) {
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case -1:
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syslog(LOG_NOTICE, "fork failed (%m)");
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return;
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case 0:
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break;
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default:
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return;
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}
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(void)signal(SIGALRM, SIG_DFL);
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(void)alarm((u_int)30);
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if ((tp = fopen(tty, "w")) == NULL) {
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dsyslog(LOG_ERR, "open `%s' (%s)", tty, strerror(errno));
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_exit(1);
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}
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if (tcgetattr(fileno(tp), &ttybuf) == -1) {
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dsyslog(LOG_ERR, "tcgetattr `%s' (%s)", tty, strerror(errno));
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_exit(1);
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}
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cr = (ttybuf.c_oflag & ONLCR) && (ttybuf.c_oflag & OPOST) ?
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"\n" : "\n\r";
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/* Set uid/gid/groups to users in case mail drop is on nfs */
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if ((p = getpwnam(ep->name)) == NULL ||
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initgroups(p->pw_name, p->pw_gid) == -1 ||
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setgid(p->pw_gid) == -1 ||
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setuid(p->pw_uid) == -1)
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_exit(1);
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if (logging)
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syslog(LOG_INFO, "biff message for %s", ep->name);
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(void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s",
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cr, ep->name, (int)sizeof(hostname), hostname, cr, cr);
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jkfprintf(tp, ep->name, offset, cr);
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(void)fclose(tp);
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_exit(0);
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}
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static void
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jkfprintf(FILE *tp, const char *name, off_t offset, const char *cr)
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{
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FILE *fi;
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int linecnt, charcnt, inheader;
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char line[BUFSIZ], visline[BUFSIZ * 4 + 1], *nl;
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if ((fi = fopen(name, "r")) == NULL)
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return;
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(void)fseeko(fi, offset, SEEK_SET);
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/*
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* Print the first 7 lines or 560 characters of the new mail
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* (whichever comes first). Skip header crap other than
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* From, Subject, To, and Date.
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*/
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linecnt = 7;
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charcnt = 560;
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inheader = 1;
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while (fgets(line, sizeof(line), fi) != NULL) {
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line[sizeof(line) - 1] = '\0';
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if (inheader) {
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if (line[0] == '\n') {
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inheader = 0;
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continue;
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}
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if (line[0] == ' ' || line[0] == '\t' ||
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(strncasecmp(line, "From:", 5) &&
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strncasecmp(line, "Subject:", 8)))
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continue;
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}
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if (strncmp(line, "From ", 5) == 0) {
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(void)fprintf(tp, "----%s", cr);
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(void)fclose(fi);
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return;
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}
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if (linecnt <= 0 || charcnt <= 0) {
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(void)fprintf(tp, "...more...%s", cr);
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(void)fclose(fi);
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return;
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}
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if ((nl = strchr(line, '\n')) != NULL)
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*nl = '\0';
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/* strip weird stuff so can't trojan horse stupid terminals */
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(void)strvis(visline, line, VIS_CSTYLE);
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(void)fputs(visline, tp);
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(void)fputs(cr, tp);
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--linecnt;
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}
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(void)fprintf(tp, "----%s\n", cr);
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(void)fclose(fi);
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}
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