/*
 *
 * parse_displayname - utility routine for splitting up display name strings
 *
 *
Copyright 1989, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.
 * *
 * Author:  Jim Fulton, MIT X Consortium
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>			/* for NULL */
#include <ctype.h>			/* for isascii() and isdigit() */
#include <X11/Xos.h>			/* for strchr() and string routines */
#include <X11/Xlib.h>			/* for Family constants */
#ifdef hpux
#include <sys/utsname.h>		/* for struct utsname */
#endif
#include <X11/Xauth.h>			/* for FamilyLocal */
#include <X11/Xmu/SysUtil.h>

#include <sys/stat.h>
#include <limits.h>

#if defined(UNIXCONN) || defined(LOCALCONN)
#define UNIX_CONNECTION "unix"
#define UNIX_CONNECTION_LENGTH 4
#endif

#include <stdlib.h>
#include "xauth.h"

/*
 * private utility routines
 */

char *
copystring (const char *src, int len)
{
    char *cp;

    if (!src && len != 0) return NULL;
    cp = malloc (len + 1);
    if (cp) {
	if (src) memcpy (cp, src, len);
	cp[len] = '\0';
    }
    return cp;
}


char *
get_local_hostname (char *buf, int maxlen)
{
    buf[0] = '\0';
    (void) XmuGetHostname (buf, maxlen);
    return (buf[0] ? buf : NULL);
}

#ifndef UNIXCONN
static char *
copyhostname (void)
{
    char buf[256];

    return (get_local_hostname (buf, sizeof buf) ?
	    copystring (buf, strlen (buf)) : NULL);
}
#endif

/*
 * parse_displayname - display a display string up into its component parts
 */
Bool
parse_displayname (const char *displayname,
		   int *familyp,	/* return */
		   char **hostp,	/* return */
		   int *dpynump,	/* return */
		   int *scrnump,	/* return */
		   char **restp)	/* return */
{
    char *ptr;				/* work variables */
    int len;				/* work variable */
    int family = -1;			/* value to be returned */
    char *host = NULL;			/* must free if set and error return */
    int dpynum = -1;			/* value to be returned */
    int scrnum = 0;			/* value to be returned */
    char *rest = NULL;			/* must free if set and error return */
    Bool dnet = False;			/* if true then using DECnet */

					/* check the name */
    if (!displayname || !displayname[0]) return False;

					/* must have at least :number */
    ptr = strrchr(displayname, ':');
    if (!ptr || !ptr[1]) return False;
    if ((ptr != displayname) && (*(ptr - 1) == ':')) {
	ptr--;
	dnet = True;
    }


    /*
     * get the host string; if none is given, use the most effiecient path
     */

    len = (ptr - displayname);	/* length of host name */
    if (len == 0) {			/* choose most efficient path */
#if defined(UNIXCONN) || defined(LOCALCONN)
	host = copystring (UNIX_CONNECTION, UNIX_CONNECTION_LENGTH);
	family = FamilyLocal;
#else
	if (dnet) {
	    host = copystring ("0", 1);
	    family = FamilyDECnet;
	} else {
	    host = copyhostname ();
	    family = FamilyInternet;
	}
#endif
    } else if (!dnet && (*displayname == '[') && (*(ptr - 1) == ']')) {
	/* Allow RFC2732-like [<IPv6NumericAddress>]:display syntax */
	family = FamilyInternet6;
	host = copystring (displayname + 1, len - 2);
    } else {
	host = copystring (displayname, len);
	if (dnet) {
	    family = dnet;
	} else {
#if defined(UNIXCONN) || defined(LOCALCONN)
	    if (host && strcmp (host, UNIX_CONNECTION) == 0)
	      family = FamilyLocal;
	    else
#endif
	      family = FamilyInternet;
	}
    }

    if (!host) return False;

    {
        /*
         * If using launchd socket, remove the screen number from the end
         * of $DISPLAY and check if it is a path to a socket.
         */
        char path[PATH_MAX];
        struct stat sbuf;

#ifdef HAVE_STRLCPY
        strlcpy(path, displayname, sizeof(path));
#else
        strncpy(path, displayname, sizeof(path) - 1);
        path[sizeof(path) - 1] = '\0';
#endif
        if (0 == stat(path, &sbuf) && S_ISSOCK(sbuf.st_mode)) {
            family = FamilyLocal;
        } else {
            char *dot = strrchr(path, '.');
            if (dot) {
                *dot = '\0';
                /* screen = atoi(dot + 1); */
                if (0 == stat(path, &sbuf) && S_ISSOCK(sbuf.st_mode)) {
                    family = FamilyLocal;
                }
            }
        }
    }

    /*
     * get the display number; we know that there is something after the
     * colon (or colons) from above.  note that host is now set and must
     * be freed if there is an error.
     */

    if (dnet) ptr++;			/* skip the extra DECnet colon */
    ptr++;				/* move to start of display num */
    {
	register char *cp;

	for (cp = ptr; *cp && isascii(*cp) && isdigit(*cp); cp++) ;
	len = (cp - ptr);
					/* check present and valid follow */
	if (len == 0 || (*cp && *cp != '.')) {
	    free (host);
	    return False;
	}

	dpynum = atoi (ptr);		/* it will handle num. as well */
	ptr = cp;
    }

    /*
     * now get screen number if given; ptr may point to nul at this point
     */
    if (ptr[0] == '.') {
	register char *cp;

	ptr++;
	for (cp = ptr; *cp && isascii(*cp) && isdigit(*cp); cp++) ;
	len = (cp - ptr);
	if (len == 0 || (*cp && *cp != '.')) {	/* all prop name */
	    free (host);
	    return False;
	}

	scrnum = atoi (ptr);		/* it will handle num. as well */
	ptr = cp;
    }

    /*
     * and finally, get any additional stuff that might be following the
     * the screen number; ptr must point to a period if there is anything
     */

    if (ptr[0] == '.') {
	ptr++;
	len = strlen (ptr);
	if (len > 0) {
	    rest = copystring (ptr, len);
	    if (!rest) {
		free (host);
		return False;
	    }
	}
    }

    /*
     * and we are done!
     */

    *familyp = family;
    *hostp = host;
    *dpynump = dpynum;
    *scrnump = scrnum;
    *restp = rest;
    return True;
}


