+void
+sys_telnet_init()
+{
+#if defined(TN3270) && defined(unix)
+ int myPid;
+#endif /* defined(TN3270) */
+
+ setconnmode();
+
+ NetNonblockingIO(net, 1);
+
+#if defined(TN3270)
+ if (noasynch == 0) { /* DBX can't handle! */
+ NetSigIO(net, 1);
+ NetSetPgrp(net);
+ }
+#endif /* defined(TN3270) */
+
+#if defined(SO_OOBINLINE)
+ SetSockOpt(net, SOL_SOCKET, SO_OOBINLINE, 1);
+#endif /* defined(SO_OOBINLINE) */
+}
+
+/*
+ * Process rings -
+ *
+ * This routine tries to fill up/empty our various rings.
+ *
+ * The parameter specifies whether this is a poll operation,
+ * or a block-until-something-happens operation.
+ *
+ * The return value is 1 if something happened, 0 if not.
+ */
+
+int
+process_rings(netin, netout, netex, ttyin, ttyout, poll)
+int poll; /* If 0, then block until something to do */
+{
+ register int c;
+ /* One wants to be a bit careful about setting returnValue
+ * to one, since a one implies we did some useful work,
+ * and therefore probably won't be called to block next
+ * time (TN3270 mode only).
+ */
+ int returnValue = 0;
+ static struct timeval TimeValue = { 0 };
+
+ if (netout) {
+ FD_SET(net, &obits);
+ }
+ if (ttyout) {
+ FD_SET(tout, &obits);
+ }
+#if defined(TN3270)
+ if (ttyin) {
+ FD_SET(tin, &ibits);
+ }
+#else /* defined(TN3270) */
+ if (ttyin) {
+ FD_SET(tin, &ibits);
+ }
+#endif /* defined(TN3270) */
+#if defined(TN3270)
+ if (netin) {
+ FD_SET(net, &ibits);
+ }
+# else /* !defined(TN3270) */
+ if (netin) {
+ FD_SET(net, &ibits);
+ }
+# endif /* !defined(TN3270) */
+ if (netex) {
+ FD_SET(net, &xbits);
+ }
+ if ((c = select(16, &ibits, &obits, &xbits,
+ (poll == 0)? (struct timeval *)0 : &TimeValue)) < 0) {
+ if (c == -1) {
+ /*
+ * we can get EINTR if we are in line mode,
+ * and the user does an escape (TSTP), or
+ * some other signal generator.
+ */
+ if (errno == EINTR) {
+ return 0;
+ }
+# if defined(TN3270)
+ /*
+ * we can get EBADF if we were in transparent
+ * mode, and the transcom process died.
+ */
+ if (errno == EBADF) {
+ /*
+ * zero the bits (even though kernel does it)
+ * to make sure we are selecting on the right
+ * ones.
+ */
+ FD_ZERO(&ibits);
+ FD_ZERO(&obits);
+ FD_ZERO(&xbits);
+ return 0;
+ }
+# endif /* defined(TN3270) */
+ /* I don't like this, does it ever happen? */
+ printf("sleep(5) from telnet, after select\r\n");
+#if defined(unix)
+ sleep(5);
+#endif /* defined(unix) */
+ }
+ return 0;
+ }
+
+ /*
+ * Any urgent data?
+ */
+ if (FD_ISSET(net, &xbits)) {
+ FD_CLR(net, &xbits);
+ SYNCHing = 1;
+ ttyflush(1); /* flush already enqueued data */
+ }
+
+ /*
+ * Something to read from the network...
+ */
+ if (FD_ISSET(net, &ibits)) {
+ int canread;
+
+ FD_CLR(net, &ibits);
+ canread = ring_empty_consecutive(&netiring);
+#if !defined(SO_OOBINLINE)
+ /*
+ * In 4.2 (and some early 4.3) systems, the
+ * OOB indication and data handling in the kernel
+ * is such that if two separate TCP Urgent requests
+ * come in, one byte of TCP data will be overlaid.
+ * This is fatal for Telnet, but we try to live
+ * with it.
+ *
+ * In addition, in 4.2 (and...), a special protocol
+ * is needed to pick up the TCP Urgent data in
+ * the correct sequence.
+ *
+ * What we do is: if we think we are in urgent
+ * mode, we look to see if we are "at the mark".
+ * If we are, we do an OOB receive. If we run
+ * this twice, we will do the OOB receive twice,
+ * but the second will fail, since the second
+ * time we were "at the mark", but there wasn't
+ * any data there (the kernel doesn't reset
+ * "at the mark" until we do a normal read).
+ * Once we've read the OOB data, we go ahead
+ * and do normal reads.
+ *
+ * There is also another problem, which is that
+ * since the OOB byte we read doesn't put us
+ * out of OOB state, and since that byte is most
+ * likely the TELNET DM (data mark), we would
+ * stay in the TELNET SYNCH (SYNCHing) state.
+ * So, clocks to the rescue. If we've "just"
+ * received a DM, then we test for the
+ * presence of OOB data when the receive OOB
+ * fails (and AFTER we did the normal mode read
+ * to clear "at the mark").
+ */
+ if (SYNCHing) {
+ int atmark;
+
+ ioctl(net, SIOCATMARK, (char *)&atmark);
+ if (atmark) {
+ c = recv(net, netiring.supply, canread, MSG_OOB);
+ if ((c == -1) && (errno == EINVAL)) {
+ c = recv(net, netiring.supply, canread, 0);
+ if (clocks.didnetreceive < clocks.gotDM) {
+ SYNCHing = stilloob(net);
+ }
+ }
+ } else {
+ c = recv(net, netiring.supply, canread, 0);
+ }
+ } else {
+ c = recv(net, netiring.supply, canread, 0);
+ }
+ settimer(didnetreceive);
+#else /* !defined(SO_OOBINLINE) */
+ c = recv(net, netiring.supply, canread, 0);
+#endif /* !defined(SO_OOBINLINE) */
+ if (c < 0 && errno == EWOULDBLOCK) {
+ c = 0;
+ } else if (c <= 0) {
+ return -1;
+ }
+ if (netdata) {
+ Dump('<', netiring.supply, c);
+ }
+ ring_supplied(&netiring, c);
+ returnValue = 1;
+ }
+
+ /*
+ * Something to read from the tty...
+ */
+ if (FD_ISSET(tin, &ibits)) {
+ FD_CLR(tin, &ibits);
+ c = TerminalRead(tin, ttyiring.supply,
+ ring_empty_consecutive(&ttyiring));
+ if (c < 0 && errno == EWOULDBLOCK) {
+ c = 0;
+ } else {
+#if defined(unix)
+ /* EOF detection for line mode!!!! */
+ if (c == 0 && MODE_LOCAL_CHARS(globalmode)) {
+ /* must be an EOF... */
+ *ttyiring.supply = termEofChar;
+ c = 1;
+ }
+#endif /* defined(unix) */
+ if (c <= 0) {
+ return -1;
+ }
+ }
+ ring_supplied(&ttyiring, c);
+ returnValue = 1; /* did something useful */
+ }
+
+ if (FD_ISSET(net, &obits)) {
+ FD_CLR(net, &obits);
+ returnValue |= netflush();
+ }
+ if (FD_ISSET(tout, &obits)) {
+ FD_CLR(tout, &obits);
+ returnValue |= ttyflush(SYNCHing|flushout);
+ }
+
+ return returnValue;
+}
projects / unix-history / commitdiff