1 #ifndef lint 2 static char sccsid[] = "@(#)talkd.c 1.4 (Berkeley) 12/20/84"; 3 #endif 4 5 /* 6 * The top level of the daemon, the format is heavily borrowed 7 * from rwhod.c. Basically: find out who and where you are; 8 * disconnect all descriptors and ttys, and then endless 9 * loop on waiting for and processing requests 10 */ 11 #include <stdio.h> 12 #include <errno.h> 13 #include <signal.h> 14 15 #include "ctl.h" 16 17 struct sockaddr_in sin = { AF_INET }; 18 19 CTL_MSG request; 20 CTL_RESPONSE response; 21 22 int sockt; 23 int debug = 0; 24 FILE *debugout; 25 int timeout(); 26 long lastmsgtime; 27 28 char hostname[32]; 29 30 #define TIMEOUT 30 31 #define MAXIDLE 120 32 33 main(argc, argv) 34 int argc; 35 char *argv[]; 36 { 37 struct sockaddr_in from; 38 int fromlen, cc; 39 40 if (debug) 41 debugout = (FILE *)fopen ("/usr/tmp/talkd.msgs", "w"); 42 43 if (getuid()) { 44 fprintf(stderr, "Talkd : not super user\n"); 45 exit(1); 46 } 47 gethostname(hostname, sizeof (hostname)); 48 (void) chdir("/dev"); 49 signal(SIGALRM, timeout); 50 alarm(TIMEOUT); 51 for (;;) { 52 extern int errno; 53 54 fromlen = sizeof(from); 55 cc = recvfrom(0, (char *)&request, sizeof (request), 0, 56 &from, &fromlen); 57 if (cc != sizeof(request)) { 58 if (cc < 0 && errno != EINTR) 59 perror("recvfrom"); 60 continue; 61 } 62 lastmsgtime = time(0); 63 swapmsg(&request); 64 if (debug) print_request(&request); 65 process_request(&request, &response); 66 /* can block here, is this what I want? */ 67 cc = sendto(sockt, (char *) &response, 68 sizeof (response), 0, &request.ctl_addr, 69 sizeof (request.ctl_addr)); 70 if (cc != sizeof(response)) 71 perror("sendto"); 72 } 73 } 74 75 timeout() 76 { 77 78 if (time(0) - lastmsgtime >= MAXIDLE) 79 exit(0); 80 alarm(TIMEOUT); 81 } 82 83 /* 84 * heuristic to detect if need to swap bytes 85 */ 86 87 swapmsg(req) 88 CTL_MSG *req; 89 { 90 if (req->ctl_addr.sin_family == ntohs(AF_INET)) { 91 req->id_num = ntohl(req->id_num); 92 req->pid = ntohl(req->pid); 93 req->addr.sin_family = ntohs(req->addr.sin_family); 94 req->ctl_addr.sin_family = 95 ntohs(req->ctl_addr.sin_family); 96 } 97 } 98