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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.
*
* RCS: @(#) $Id: tclUnixSock.c,v 1.1.2.4 1998/12/10 21:21:58 stanton Exp $
*/
#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;
#ifdef TCL_THREADS
static Tcl_Mutex hostMutex;
#endif
/*
*----------------------------------------------------------------------
*
* 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;
#else
char buffer[sizeof(hostname)];
#endif
char *native;
Tcl_MutexLock(&hostMutex);
if (hostnameInited) {
Tcl_MutexUnlock(&hostMutex);
return hostname;
}
native = NULL;
#ifndef NO_UNAME
(VOID *) memset((VOID *) &u, (int) 0, sizeof(struct utsname));
if (uname(&u) > -1) { /* INTL: Native. */
hp = gethostbyname(u.nodename); /* INTL: Native. */
if (hp != NULL) {
native = hp->h_name;
} else {
native = u.nodename;
}
}
#else
/*
* Uname doesn't exist; try gethostname instead.
*/
if (gethostname(buffer, sizeof(buffer)) > -1) { /* INTL: Native. */
native = buffer;
}
#endif
if (native == NULL) {
hostname[0] = 0;
} else {
Tcl_ExternalToUtf(NULL, NULL, native, -1, 0, NULL, hostname,
sizeof(hostname), NULL, NULL, NULL);
}
hostnameInited = 1;
Tcl_MutexUnlock(&hostMutex);
return hostname;
}
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