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+/*
+ * tclUnixSock.c --
+ *
+ * This file contains Unix-specific socket related code.
+ *
+ * Copyright (c) 1995 Sun Microsystems, Inc.
+ *
+ * See the file "license.terms" for information on usage and redistribution
+ * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ *
+ * SCCS: @(#) tclUnixSock.c 1.9 97/10/09 18:24:49
+ */
+
+#include "tcl.h"
+#include "tclPort.h"
+
+/*
+ * There is no portable macro for the maximum length
+ * of host names returned by gethostbyname(). We should only
+ * trust SYS_NMLN if it is at least 255 + 1 bytes to comply with DNS
+ * host name limits.
+ *
+ * Note: SYS_NMLN is a restriction on "uname" not on gethostbyname!
+ *
+ * For example HP-UX 10.20 has SYS_NMLN == 9, while gethostbyname()
+ * can return a fully qualified name from DNS of up to 255 bytes.
+ *
+ * Fix suggested by Viktor Dukhovni (viktor@esm.com)
+ */
+
+#if defined(SYS_NMLN) && SYS_NMLEN >= 256
+#define TCL_HOSTNAME_LEN SYS_NMLEN
+#else
+#define TCL_HOSTNAME_LEN 256
+#endif
+
+
+/*
+ * The following variable holds the network name of this host.
+ */
+
+static char hostname[TCL_HOSTNAME_LEN + 1];
+static int hostnameInited = 0;
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetHostName --
+ *
+ * Returns the name of the local host.
+ *
+ * Results:
+ * A string containing the network name for this machine, or
+ * an empty string if we can't figure out the name. The caller
+ * must not modify or free this string.
+ *
+ * Side effects:
+ * None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+char *
+Tcl_GetHostName()
+{
+#ifndef NO_UNAME
+ struct utsname u;
+ struct hostent *hp;
+#endif
+
+ if (hostnameInited) {
+ return hostname;
+ }
+
+#ifndef NO_UNAME
+ (VOID *) memset((VOID *) &u, (int) 0, sizeof(struct utsname));
+ if (uname(&u) > -1) {
+ hp = gethostbyname(u.nodename);
+ if (hp != NULL) {
+ strcpy(hostname, hp->h_name);
+ } else {
+ strcpy(hostname, u.nodename);
+ }
+ hostnameInited = 1;
+ return hostname;
+ }
+#else
+ /*
+ * Uname doesn't exist; try gethostname instead.
+ */
+
+ if (gethostname(hostname, sizeof(hostname)) > -1) {
+ hostnameInited = 1;
+ return hostname;
+ }
+#endif
+
+ hostname[0] = 0;
+ return hostname;
+}