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