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/* $OpenBSD: talkd.c,v 1.23 2015/01/16 06:39:51 deraadt Exp $ */
/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* The top level of the daemon, the format is heavily borrowed
* from rwhod.c. Basically: find out who and where you are;
* disconnect all descriptors and ttys, and then endless
* loop on waiting for and processing requests
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <protocols/talkd.h>
#include <signal.h>
#include <syslog.h>
#include <time.h>
#include <errno.h>
#include <unistd.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <paths.h>
#include "talkd.h"
int debug = 0;
void timeout(int);
long lastmsgtime;
char hostname[HOST_NAME_MAX+1];
#define TIMEOUT 30
#define MAXIDLE 120
int
main(int argc, char *argv[])
{
if (getuid() != 0) {
fprintf(stderr, "%s: getuid: not super-user\n", argv[0]);
exit(1);
}
openlog("talkd", LOG_PID, LOG_DAEMON);
if (gethostname(hostname, sizeof(hostname)) < 0) {
syslog(LOG_ERR, "gethostname: %m");
_exit(1);
}
if (chdir(_PATH_DEV) < 0) {
syslog(LOG_ERR, "chdir: %s: %m", _PATH_DEV);
_exit(1);
}
if (argc > 1 && strcmp(argv[1], "-d") == 0)
debug = 1;
init_table();
signal(SIGALRM, timeout);
alarm(TIMEOUT);
for (;;) {
CTL_RESPONSE response;
socklen_t len = sizeof(response.addr);
CTL_MSG request;
int cc;
struct sockaddr ctl_addr;
memset(&response, 0, sizeof(response));
cc = recvfrom(STDIN_FILENO, (char *)&request,
sizeof(request), 0, (struct sockaddr *)&response.addr,
&len);
if (cc != sizeof(request)) {
if (cc < 0 && errno != EINTR)
syslog(LOG_WARNING, "recvfrom: %m");
continue;
}
/* Force NUL termination */
request.l_name[sizeof(request.l_name) - 1] = '\0';
request.r_name[sizeof(request.r_name) - 1] = '\0';
request.r_tty[sizeof(request.r_tty) - 1] = '\0';
memcpy(&ctl_addr, &request.ctl_addr, sizeof(ctl_addr));
ctl_addr.sa_family = ntohs(request.ctl_addr.sa_family);
ctl_addr.sa_len = sizeof(ctl_addr);
if (ctl_addr.sa_family != AF_INET)
continue;
lastmsgtime = time(0);
process_request(&request, &response);
/* can block here, is this what I want? */
cc = sendto(STDOUT_FILENO, (char *)&response,
sizeof(response), 0, &ctl_addr, sizeof(ctl_addr));
if (cc != sizeof(response))
syslog(LOG_WARNING, "sendto: %m");
}
}
void
timeout(int signo)
{
int save_errno = errno;
if (time(0) - lastmsgtime >= MAXIDLE)
_exit(0);
alarm(TIMEOUT);
errno = save_errno;
}
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