static void
InitializeHostName(
char **valuePtr,
int *lengthPtr,
Tcl_Encoding *encodingPtr)
{
const char *native = NULL;
#ifndef NO_UNAME
struct utsname u;
struct hostent *hp;
memset(&u, (int) 0, sizeof(struct utsname));
if (uname(&u) > -1) { /* INTL: Native. */
hp = TclpGetHostByName(u.nodename); /* INTL: Native. */
if (hp == NULL) {
/*
* Sometimes the nodename is fully qualified, but gets truncated
* as it exceeds SYS_NMLN. See if we can just get the immediate
* nodename and get a proper answer that way.
*/
char *dot = strchr(u.nodename, '.');
if (dot != NULL) {
char *node = ckalloc(dot - u.nodename + 1);
memcpy(node, u.nodename, (size_t) (dot - u.nodename));
node[dot - u.nodename] = '\0';
hp = TclpGetHostByName(node);
ckfree(node);
}
}
if (hp != NULL) {
native = hp->h_name;
} else {
native = u.nodename;
}
}
if (native == NULL) {
native = tclEmptyStringRep;
}
#else /* !NO_UNAME */
/*
* Uname doesn't exist; try gethostname instead.
*
* 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 ([email protected])
*/
# if defined(SYS_NMLN) && (SYS_NMLEN >= 256)
char buffer[SYS_NMLEN];
# else
char buffer[256];
# endif
if (gethostname(buffer, sizeof(buffer)) > -1) { /* INTL: Native. */
native = buffer;
}
#endif /* NO_UNAME */
*encodingPtr = Tcl_GetEncoding(NULL, NULL);
*lengthPtr = strlen(native);
*valuePtr = ckalloc((*lengthPtr) + 1);
memcpy(*valuePtr, native, (size_t)(*lengthPtr)+1);
}
EXPORT_C CONST char *
Tcl_GetHostName()
{
#ifndef NO_UNAME
struct utsname u;
struct hostent *hp;
#else
char buffer[sizeof(hostname)];
#endif
CONST 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 = TclpGetHostByName(u.nodename); /* INTL: Native. */
if (hp == NULL) {
/*
* Sometimes the nodename is fully qualified, but gets truncated
* as it exceeds SYS_NMLN. See if we can just get the immediate
* nodename and get a proper answer that way.
*/
char *dot = strchr(u.nodename, '.');
if (dot != NULL) {
char *node = ckalloc((unsigned) (dot - u.nodename + 1));
memcpy(node, u.nodename, (size_t) (dot - u.nodename));
node[dot - u.nodename] = '\0';
hp = TclpGetHostByName(node);
ckfree(node);
}
}
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;
}
