1 /* $OpenBSD: talkd.c,v 1.22 2009/10/27 23:59:31 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 1983 Regents of the University of California. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /* 33 * The top level of the daemon, the format is heavily borrowed 34 * from rwhod.c. Basically: find out who and where you are; 35 * disconnect all descriptors and ttys, and then endless 36 * loop on waiting for and processing requests 37 */ 38 #include <sys/param.h> 39 #include <sys/types.h> 40 #include <sys/socket.h> 41 #include <protocols/talkd.h> 42 #include <signal.h> 43 #include <syslog.h> 44 #include <time.h> 45 #include <errno.h> 46 #include <unistd.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <paths.h> 51 #include "talkd.h" 52 53 int debug = 0; 54 void timeout(int); 55 long lastmsgtime; 56 57 char hostname[MAXHOSTNAMELEN]; 58 59 #define TIMEOUT 30 60 #define MAXIDLE 120 61 62 int 63 main(int argc, char *argv[]) 64 { 65 if (getuid() != 0) { 66 fprintf(stderr, "%s: getuid: not super-user\n", argv[0]); 67 exit(1); 68 } 69 openlog("talkd", LOG_PID, LOG_DAEMON); 70 if (gethostname(hostname, sizeof(hostname)) < 0) { 71 syslog(LOG_ERR, "gethostname: %m"); 72 _exit(1); 73 } 74 if (chdir(_PATH_DEV) < 0) { 75 syslog(LOG_ERR, "chdir: %s: %m", _PATH_DEV); 76 _exit(1); 77 } 78 if (argc > 1 && strcmp(argv[1], "-d") == 0) 79 debug = 1; 80 init_table(); 81 signal(SIGALRM, timeout); 82 alarm(TIMEOUT); 83 84 for (;;) { 85 CTL_RESPONSE response; 86 socklen_t len = sizeof(response.addr); 87 CTL_MSG request; 88 int cc; 89 struct sockaddr ctl_addr; 90 91 memset(&response, 0, sizeof(response)); 92 cc = recvfrom(STDIN_FILENO, (char *)&request, 93 sizeof(request), 0, (struct sockaddr *)&response.addr, 94 &len); 95 if (cc != sizeof(request)) { 96 if (cc < 0 && errno != EINTR) 97 syslog(LOG_WARNING, "recvfrom: %m"); 98 continue; 99 } 100 101 /* Force NUL termination */ 102 request.l_name[sizeof(request.l_name) - 1] = '\0'; 103 request.r_name[sizeof(request.r_name) - 1] = '\0'; 104 request.r_tty[sizeof(request.r_tty) - 1] = '\0'; 105 106 memcpy(&ctl_addr, &request.ctl_addr, sizeof(ctl_addr)); 107 ctl_addr.sa_family = ntohs(request.ctl_addr.sa_family); 108 ctl_addr.sa_len = sizeof(ctl_addr); 109 if (ctl_addr.sa_family != AF_INET) 110 continue; 111 112 lastmsgtime = time(0); 113 process_request(&request, &response); 114 /* can block here, is this what I want? */ 115 cc = sendto(STDOUT_FILENO, (char *)&response, 116 sizeof(response), 0, &ctl_addr, sizeof(ctl_addr)); 117 if (cc != sizeof(response)) 118 syslog(LOG_WARNING, "sendto: %m"); 119 } 120 } 121 122 void 123 timeout(int signo) 124 { 125 int save_errno = errno; 126 127 if (time(0) - lastmsgtime >= MAXIDLE) 128 _exit(0); 129 alarm(TIMEOUT); 130 errno = save_errno; 131 } 132