/* * main.c - webster server * * This file has all the code to handle the network connections. * * David A. Curry * Purdue University * Engineering Computer Network * April, 1986 * * $Log: main.c,v $ * Revision 1.5 91/07/09 00:20:44 ambar * reformatted * * Revision 1.4 88/02/25 22:47:20 ambar * changed the location of our header files. * * Revision 1.3 88/02/20 05:39:13 ambar * ifdef'd out if SUNRPC is defined. * * Revision 1.2 87/06/16 23:40:25 jtkohl * fix lossage with signals and openlog * * Revision 1.1 87/06/13 19:21:54 jtkohl * Initial revision * * Revision 1.3 86/12/26 22:03:43 davy * Changed cpu time limit to 15 minutes. * * Revision 1.2 86/12/26 22:02:38 davy * Changed to work with DBM files. * */ #ifndef lint static char rcsid_main_c[] = "$Header: /afs/sipb.mit.edu/project/sipbsrc/src/webster/src/server/RCS/main.c,v 1.5 91/07/09 00:20:44 ambar Exp $"; #endif #ifndef SUNRPC #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include FILE *input; /* input file pointer */ FILE *output; /* output file pointer */ DBM *db; /* database file pointer */ FILE *indexfp; /* index file pointer */ struct header hdr; /* index file header */ extern int errno; main() { char *whereis(); union wait status; struct rlimit rlim; register int i, s, sock; int length, myport, hisport; char myname[64], hisname[64]; extern int byebye(), pickup(); struct sockaddr_in mysin, hissin; #ifndef DEBUG /* * Detach from the parent. */ if (fork()) exit(0); /* * Zap the process group. */ setpgrp(0, 0); /* * Close files. */ for (i = 0; i < NOFILE; i++) close(i); /* * Ignore signals. */ for (i = 0; i < NSIG; i++) signal(i, SIG_IGN); signal(SIGTERM, byebye); signal(SIGXCPU, byebye); signal(SIGCHLD, pickup); signal(SIGSEGV, SIG_DFL); signal(SIGBUS, SIG_DFL); signal(SIGFPE, SIG_DFL); /* * Reset stdin, stdout, stderr. */ open("/dev/null", O_RDONLY); open("/dev/null", O_WRONLY); dup(1); /* * Clear controlling tty. */ if ((i = open("/dev/tty", O_RDWR)) > 0) { ioctl(i, TIOCNOTTY, 0); close(i); } #endif /* * Kick our limits. */ rlim.rlim_max = rlim.rlim_cur = RLIM_INFINITY; setrlimit(RLIMIT_FSIZE, &rlim); setrlimit(RLIMIT_STACK, &rlim); setrlimit(RLIMIT_DATA, &rlim); /* * Open the logfile. */ openlog("websterd", LOG_PID, LOG_LOCAL5); /* * Figure out who we are. */ whoami(myname, &myport, &mysin); /* * Get a socket. */ if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) { syslog(LOG_ERR, "socket: %m"); exit(1); } /* * Bind a name to the socket, so clients can connect * to us. */ if (bind(sock, &mysin, sizeof(struct sockaddr_in)) < 0) { syslog(LOG_ERR, "bind: %m"); exit(1); } /* * Listen for connections. */ if (listen(sock, 5) < 0) { syslog(LOG_ERR, "listen: %m"); exit(1); } /* * Forever... */ for (;;) { /* * Pick up dead children. */ while (wait3(&status, WNOHANG, 0) > 0) ; /* * Accept a connection. This blocks until a * connection arrives. */ length = sizeof(struct sockaddr_in); /* * EINTR is okay; that comes from SIGCHLD's * coming in. */ if ((s = accept(sock, &hissin, &length)) < 0) { if (errno != EINTR) syslog(LOG_ERR, "accept: %m"); continue; } /* * Save information about our client. */ hisport = ntohs(hissin.sin_port); strcpy(hisname, whereis(hissin.sin_addr.s_addr)); /* * The child process waits on the client. */ if (fork() == 0) { input = fdopen(s, "r"); output = fdopen(s, "w"); /* * Chop CPU time limit in case we don't get * disconnected right and spin instead. */ rlim.rlim_max = rlim.rlim_cur = 15 * 60; /* 15 min */ setrlimit(RLIMIT_CPU, &rlim); /* * Load the index file, then * go to the dictionary. */ loadindex(); webster(); byebye(); } close(s); } } /* * whoami - find out what host we're on, what port we should * be listening to, etc. */ whoami(name, port, sin) char *name; int *port; struct sockaddr_in *sin; { char host[64]; register struct hostent *hp; register struct servent *sp; struct hostent *gethostbyname(); struct servent *getservbyname(); /* * Get our hostname. */ if (gethostname(host, sizeof(host)) < 0) { syslog(LOG_ERR, "gethostname: %m"); exit(1); } /* * Look ourselves up. */ if ((hp = gethostbyname(host)) == NULL) { syslog(LOG_ERR, "%s: unknown host.", host); exit(1); } /* * Get the socket number we listen on. */ if ((sp = getservbyname(WEBSTERNAME, "tcp")) == NULL) *port = WEBSTERPORT; else *port = ntohs(sp->s_port); /* * Use our formal name. */ strcpy(name, hp->h_name); /* * Construct our address. */ bzero(sin, sizeof(struct sockaddr_in)); sin->sin_family = AF_INET; sin->sin_port = htons(*port); bcopy(hp->h_addr, &(sin->sin_addr), hp->h_length); } /* * whereis - find out the host name which goes with an address. */ char *whereis(addr) long addr; { register struct hostent *hp; struct hostent *gethostbyaddr(); if ((hp = gethostbyaddr(&addr, sizeof(long), AF_INET)) == NULL) return("(unknown)"); return(hp->h_name); } /* * loadindex - read in the index file header, open the database. */ loadindex() { FILE *fp; char buf[BUFSIZ]; /* * Header. */ sprintf(buf, "%s/%s", wordfiledir, wordfilehdr); if ((fp = fopen(buf, "r")) == NULL) { syslog(LOG_ERR, "cannot open \"%s\".", buf); exit(1); } if (fread(&hdr, sizeof(struct header), 1, fp) != 1) { syslog(LOG_ERR, "bad hdr read from \"%s\".", buf); exit(1); } fclose(fp); /* * Index file. */ sprintf(buf, "%s/%s", wordfiledir, wordfileindex); if ((indexfp = fopen(buf, "r")) == NULL) { syslog(LOG_ERR, "cannot open \"%s\".", buf); exit(1); } /* * Database. */ if ((db = dbm_open(buf, O_RDONLY, 0644)) == NULL) { syslog(LOG_ERR, "cannot open index database."); exit(1); } } byebye() { register int i; static int beenhere = 0; /* * Sigh. This lets us avoid hanging on a close. */ if (!beenhere) { beenhere = 1; signal(SIGALRM, byebye); alarm(30); for (i = 0; i < NOFILE; i++) close(i); } _exit(0); } pickup() { union wait status; while (wait3(&status, WNOHANG, 0) > 0) ; } #ifdef DEBUG openlog(s, p, n) char *s; int p, n; { return; } syslog(n, s, a) int n; char *s, *a; { fprintf(stderr, s, a); } #endif #endif !SUNRPC