/*
 * $XConsortium: access.c,v 1.14 93/09/20 18:03:26 hersh Exp $
 *
Copyright (c) 1990  X Consortium

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

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
X CONSORTIUM 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 X Consortium 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 X Consortium.
 *
 * Author:  Keith Packard, MIT X Consortium
 */

/*
 * Access control for XDMCP - keep a database of allowable display addresses
 * and (potentially) a list of hosts to send ForwardQuery packets to
 */

# include   "dm.h"

#ifdef XDMCP

# include   <X11/Xos.h>
# include   <X11/Xdmcp.h>
# include   <X11/X.h>
# include   <stdio.h>
# include   <ctype.h>
# include   <netinet/in.h>
# include   <netdb.h>
# include   <sys/socket.h>

#define ALIAS_CHARACTER	    '%'
#define NEGATE_CHARACTER    '!'
#define CHOOSER_STRING	    "CHOOSER"
#define BROADCAST_STRING    "BROADCAST"

#define HOST_ALIAS	0
#define HOST_ADDRESS	1
#define HOST_BROADCAST	2
#define HOST_CHOOSER	3

typedef struct _hostEntry {
    struct _hostEntry	*next;
    int	    type;
    union _hostOrAlias {
	char	*aliasName;
	ARRAY8	hostAddress;
    } entry;
} HostEntry;

#define DISPLAY_ALIAS	    0
#define DISPLAY_PATTERN	    1
#define DISPLAY_ADDRESS	    2

typedef struct _displayEntry {
    struct _displayEntry    *next;
    int			    type;
    int			    notAllowed;
    int			    chooser;
    union _displayType {
	char		    *aliasName;
	char		    *displayPattern;
	struct _display {
	    ARRAY8	    clientAddress;
	    CARD16	    connectionType;
	} displayAddress;
    } entry;
    HostEntry		    *hosts;
} DisplayEntry;

static DisplayEntry	*database;

static ARRAY8		localAddress;

ARRAY8Ptr
getLocalAddress ()
{
    static int	haveLocalAddress;
    
    if (!haveLocalAddress)
    {
	struct hostent	*hostent;

	hostent = gethostbyname (localHostname());
	XdmcpAllocARRAY8 (&localAddress, hostent->h_length);
	memmove( localAddress.data, hostent->h_addr, hostent->h_length);
    }
    return &localAddress;
}

static void
FreeHostEntry (h)
    HostEntry	    *h;
{
    switch (h->type) {
    case HOST_ALIAS:
	free (h->entry.aliasName);
	break;
    case HOST_ADDRESS:
	XdmcpDisposeARRAY8 (&h->entry.hostAddress);
	break;
    case HOST_CHOOSER:
	break;
    }
    free ((char *) h);
}

static void
FreeDisplayEntry (d)
    DisplayEntry    *d;
{
    HostEntry	*h, *next;
    switch (d->type) {
    case DISPLAY_ALIAS:
	free (d->entry.aliasName);
	break;
    case DISPLAY_PATTERN:
	free (d->entry.displayPattern);
	break;
    case DISPLAY_ADDRESS:
	XdmcpDisposeARRAY8 (&d->entry.displayAddress);
	break;
    }
    for (h = d->hosts; h; h = next) {
	next = h->next;
	FreeHostEntry (h);
    }
    free ((char *) d);
}

static void
FreeAccessDatabase ()
{
    DisplayEntry    *d, *next;

    for (d = database; d; d = next)
    {
	next = d->next;
	FreeDisplayEntry (d);
    }
    database = 0;
}

#define WORD_LEN    256
static char	wordBuffer[WORD_LEN];
static int	nextIsEOF;

static char *
ReadWord (file, EOFatEOL)
    FILE    *file;
    int	    EOFatEOL;
{
    int	    c;
    char    *wordp;
    int	    quoted;

    wordp = wordBuffer;
    if (nextIsEOF)
    {
	nextIsEOF = FALSE;
	return NULL;
    }
    quoted = FALSE;
    for (;;) {
	c = getc (file);
	switch (c) {
	case '#':
	    if (quoted)
	    {
		*wordp++ = c;
		break;
	    }
	    while ((c = getc (file)) != EOF && c != '\n')
		;
	case '\n':
	case EOF:
	    if (c == EOF || (EOFatEOL && !quoted))
	    {
		ungetc (c, file);
		if (wordp == wordBuffer)
		    return NULL;
		*wordp = '\0';
		nextIsEOF = TRUE;
		return wordBuffer;
	    }
	case ' ':
	case '\t':
	    if (wordp != wordBuffer)
	    {
		ungetc (c, file);
		*wordp = '\0';
		return wordBuffer;
	    }
	    break;
	case '\\':
	    if (!quoted)
	    {
		quoted = TRUE;
		continue;
	    }
	default:
	    *wordp++ = c;
	    break;
	}
	quoted = FALSE;
    }
}

static HostEntry *
ReadHostEntry (file)
    FILE    *file;
{
    char	    *hostOrAlias;
    HostEntry	    *h;
    struct hostent  *hostent;

tryagain:
    hostOrAlias = ReadWord (file, TRUE);
    if (!hostOrAlias)
	return NULL;
    h = (HostEntry *) malloc (sizeof (DisplayEntry));
    if (*hostOrAlias == ALIAS_CHARACTER)
    {
	h->type = HOST_ALIAS;
	h->entry.aliasName = malloc (strlen (hostOrAlias) + 1);
	if (!h->entry.aliasName) {
	    free ((char *) h);
	    return NULL;
	}
	strcpy (h->entry.aliasName, hostOrAlias);
    }
    else if (!strcmp (hostOrAlias, CHOOSER_STRING))
    {
	h->type = HOST_CHOOSER;
    }
    else if (!strcmp (hostOrAlias, BROADCAST_STRING))
    {
	h->type = HOST_BROADCAST;
    }
    else
    {
	h->type = HOST_ADDRESS;
	hostent = gethostbyname (hostOrAlias);
	if (!hostent)
	{
	    Debug ("No such host %s\n", hostOrAlias);
	    LogError ("Access file \"%s\", host \"%s\" not found\n", accessFile, hostOrAlias);
	    free ((char *) h);
	    goto tryagain;
	}
	if (!XdmcpAllocARRAY8 (&h->entry.hostAddress, hostent->h_length))
	{
	    LogOutOfMem ("ReadHostEntry\n");
	    free ((char *) h);
	    return NULL;
	}
	memmove( h->entry.hostAddress.data, hostent->h_addr, hostent->h_length);
    }
    return h;
}

static int
HasGlobCharacters (s)
    char    *s;
{
    for (;;)
	switch (*s++) {
	case '?':
	case '*':
	    return 1;
	case '\0':
	    return 0;
	}
}

static DisplayEntry *
ReadDisplayEntry (file)
    FILE    *file;
{
    char	    *displayOrAlias;
    DisplayEntry    *d;
    struct _display *display;
    HostEntry	    *h, **prev;
    struct hostent  *hostent;
    
    displayOrAlias = ReadWord (file, FALSE);
    if (!displayOrAlias)
    	return NULL;
    d = (DisplayEntry *) malloc (sizeof (DisplayEntry));
    d->notAllowed = 0;
    d->chooser = 0;
    if (*displayOrAlias == ALIAS_CHARACTER)
    {
	d->type = DISPLAY_ALIAS;
	d->entry.aliasName = malloc (strlen (displayOrAlias) + 1);
	if (!d->entry.aliasName)
	{
	    free ((char *) d);
	    return NULL;
	}
	strcpy (d->entry.aliasName, displayOrAlias);
    }
    else
    {
	if (*displayOrAlias == NEGATE_CHARACTER)
	{
	    d->notAllowed = 1;
	    ++displayOrAlias;
	}
    	if (HasGlobCharacters (displayOrAlias))
    	{
	    d->type = DISPLAY_PATTERN;
	    d->entry.displayPattern = malloc (strlen (displayOrAlias) + 1);
	    if (!d->entry.displayPattern)
	    {
	    	free ((char *) d);
	    	return NULL;
	    }
	    strcpy (d->entry.displayPattern, displayOrAlias);
    	}
    	else
    	{
	    if ((hostent = gethostbyname (displayOrAlias)) == NULL)
	    {
		LogError ("Access file %s, display %s unknown\n", accessFile, displayOrAlias);
		free ((char *) d);
		return NULL;
	    }
	    d->type = DISPLAY_ADDRESS;
	    display = &d->entry.displayAddress;
	    if (!XdmcpAllocARRAY8 (&display->clientAddress, hostent->h_length))
	    {
	    	free ((char *) d);
	    	return NULL;
	    }
	    memmove( display->clientAddress.data, hostent->h_addr, hostent->h_length);
	    switch (hostent->h_addrtype)
	    {
#ifdef AF_UNIX
	    case AF_UNIX:
	    	display->connectionType = FamilyLocal;
	    	break;
#endif
#ifdef AF_INET
	    case AF_INET:
	    	display->connectionType = FamilyInternet;
	    	break;
#endif
#ifdef AF_DECnet
	    case AF_DECnet:
	    	display->connectionType = FamilyDECnet;
	    	break;
#endif
	    default:
	    	display->connectionType = FamilyLocal;
	    	break;
	    }
    	}
    }
    prev = &d->hosts;
    while (h = ReadHostEntry (file))
    {
	if (h->type == HOST_CHOOSER)
	{
	    FreeHostEntry (h);
	    d->chooser = 1;
	} else {
	    *prev = h;
	    prev = &h->next;
	}
    }
    *prev = NULL;
    return d;
}

static
ReadAccessDatabase (file)
    FILE    *file;
{
    DisplayEntry    *d, **prev;

    prev = &database;
    while (d = ReadDisplayEntry (file))
    {
	*prev = d;
	prev = &d->next;
    }
    *prev = NULL;
}

ScanAccessDatabase ()
{
    FILE	*datafile;

    FreeAccessDatabase ();
    if (*accessFile)
    {
    	datafile = fopen (accessFile, "r");
    	if (!datafile)
	{
	    LogError ("Cannot open access control file %s, no XDMCP reqeusts will be granted\n", accessFile);
	    return 0;
	}
	ReadAccessDatabase (datafile);
	fclose (datafile);
    }
    return 1;
}

/*
 * calls the given function for each valid indirect entry.  Returns TRUE if
 * the local host exists on any of the lists, else FALSE
 */

#define MAX_DEPTH   32

static int indirectAlias ();

static int
scanHostlist (h, clientAddress, connectionType, function, closure, depth, broadcast)
    HostEntry	*h;
    ARRAY8Ptr	clientAddress;
    CARD16	connectionType;
    int		(*function)();
    char	*closure;
    int		depth;
    int		broadcast;
{
    int	haveLocalhost = 0;

    for (; h; h = h->next)
    {
	switch (h->type) {
	case HOST_ALIAS:
	    if (indirectAlias (h->entry.aliasName, clientAddress,
			       connectionType, function, closure, depth,
			       broadcast))
		haveLocalhost = 1;
	    break;
	case HOST_ADDRESS:
	    if (XdmcpARRAY8Equal (getLocalAddress(), &h->entry.hostAddress))
		haveLocalhost = 1;
	    else if (function)
		(*function) (connectionType, &h->entry.hostAddress, closure);
	    break;
	case HOST_BROADCAST:
	    if (broadcast)
	    {
		ARRAY8	temp;

		if (function)
		{
		    temp.data = (BYTE *) BROADCAST_STRING;
		    temp.length = strlen ((char *)temp.data);
		    (*function) (connectionType, &temp, closure);
		}
	    }
	    break;
	}
    }
    return haveLocalhost;
}

/* Returns non-0 iff string is matched by pattern.  Does case folding.
 */
static int
patternMatch (string, pattern)
    char    *string, *pattern;
{
    int	    p, s;

    if (!string)
	string = "";

    for (;;)
    {
	s = *string++;
	switch (p = *pattern++) {
	case '*':
	    if (!*pattern)
		return 1;
	    for (string--; *string; string++)
		if (patternMatch (string, pattern))
		    return 1;
	    return 0;
	case '?':
	    if (s == '\0')
		return 0;
	    break;
	case '\0':
	    return s == '\0';
	case '\\':
	    p = *pattern++;
	    /* fall through */
	default:
	    if (isupper(p)) p = tolower(p);
	    if (isupper(s)) s = tolower(s);
	    if (p != s)
		return 0;
	}
    }
}

static int
indirectAlias (alias, clientAddress, connectionType, function, closure, depth,
	       broadcast)
    char	*alias;
    ARRAY8Ptr	clientAddress;
    CARD16	connectionType;
    int		(*function)();
    char	*closure;
    int		depth;
    int		broadcast;
{
    DisplayEntry    *d;
    int		    haveLocalhost = 0;

    if (depth == MAX_DEPTH)
	return 0;
    for (d = database; d; d = d->next)
    {
	if (d->type != DISPLAY_ALIAS || !patternMatch (alias, d->entry.aliasName))
	    continue;
	if (scanHostlist (d->hosts, clientAddress, connectionType,
			  function, closure, depth + 1, broadcast))
	{
	    haveLocalhost = 1;
	}
    }
    return haveLocalhost;
}

ARRAY8Ptr IndirectChoice ();

ForEachMatchingIndirectHost (clientAddress, connectionType, function, closure)
    ARRAY8Ptr	clientAddress;
    CARD16	connectionType;
    int		(*function)();
    char	*closure;
{
    int		    haveLocalhost = 0;
    DisplayEntry    *d;
    char	    *clientName = 0, *NetworkAddressToHostname ();

    for (d = database; d; d = d->next)
    {
    	switch (d->type) {
    	case DISPLAY_ALIAS:
	    continue;
    	case DISPLAY_PATTERN:
	    if (!clientName)
		clientName = NetworkAddressToHostname (connectionType,
						       clientAddress);
	    if (!patternMatch (clientName, d->entry.displayPattern))
		continue;
	    break;
    	case DISPLAY_ADDRESS:
	    if (d->entry.displayAddress.connectionType != connectionType ||
	    	!XdmcpARRAY8Equal (&d->entry.displayAddress.clientAddress,
				  clientAddress))
	    {
		continue;
	    }
	    break;
    	}
	if (!d->hosts)
	    continue;
	if (d->notAllowed)
	    break;
	if (d->chooser)
	{
	    ARRAY8Ptr	choice;

	    choice = IndirectChoice (clientAddress, connectionType);
	    if (!choice || XdmcpARRAY8Equal (getLocalAddress(), choice))
		haveLocalhost = 1;
	    else
		(*function) (connectionType, choice, closure);
	}
	else if (scanHostlist (d->hosts, clientAddress, connectionType,
			  function, closure, 0, FALSE))
	{
	    haveLocalhost = 1;
	}
	break;
    }
    if (clientName)
	free (clientName);
    return haveLocalhost;
}

UseChooser (clientAddress, connectionType)
    ARRAY8Ptr	clientAddress;
    CARD16	connectionType;
{
    DisplayEntry    *d;
    char	    *clientName = 0, *NetworkAddressToHostname ();

    for (d = database; d; d = d->next)
    {
    	switch (d->type) {
    	case DISPLAY_ALIAS:
	    continue;
    	case DISPLAY_PATTERN:
	    if (!clientName)
		clientName = NetworkAddressToHostname (connectionType,
						       clientAddress);
	    if (!patternMatch (clientName, d->entry.displayPattern))
		continue;
	    break;
    	case DISPLAY_ADDRESS:
	    if (d->entry.displayAddress.connectionType != connectionType ||
	    	!XdmcpARRAY8Equal (&d->entry.displayAddress.clientAddress,
				  clientAddress))
	    {
		continue;
	    }
	    break;
    	}
	if (!d->hosts)
	    continue;
	if (d->notAllowed)
	    break;
	if (d->chooser && !IndirectChoice (clientAddress, connectionType))
	    return 1;
	break;
    }
    return 0;
}

ForEachChooserHost (clientAddress, connectionType, function, closure)
    ARRAY8Ptr	clientAddress;
    CARD16	connectionType;
    int		(*function)();
    char	*closure;
{
    int		    haveLocalhost = 0;
    DisplayEntry    *d;
    char	    *clientName = 0, *NetworkAddressToHostname ();

    for (d = database; d; d = d->next)
    {
    	switch (d->type) {
    	case DISPLAY_ALIAS:
	    continue;
    	case DISPLAY_PATTERN:
	    if (!clientName)
		clientName = NetworkAddressToHostname (connectionType,
						       clientAddress);
	    if (!patternMatch (clientName, d->entry.displayPattern))
		continue;
	    break;
    	case DISPLAY_ADDRESS:
	    if (d->entry.displayAddress.connectionType != connectionType ||
	    	!XdmcpARRAY8Equal (&d->entry.displayAddress.clientAddress,
				  clientAddress))
	    {
		continue;
	    }
	    break;
    	}
	if (!d->hosts)
	    continue;
	if (d->notAllowed)
	    break;
	if (!d->chooser)
	    break;
	if (scanHostlist (d->hosts, clientAddress, connectionType,
			  function, closure, 0, TRUE))
	{
	    haveLocalhost = 1;
	}
	break;
    }
    if (clientName)
	free (clientName);
    if (haveLocalhost)
	(*function) (connectionType, getLocalAddress(), closure);
}

/*
 * returns TRUE if the given client is acceptable to the local host.  The
 * given display client is acceptable if it occurs without a host list.
 */

AcceptableDisplayAddress (clientAddress, connectionType, type)
    ARRAY8Ptr	clientAddress;
    CARD16	connectionType;
    xdmOpCode	type;
{
    DisplayEntry    *d;
    char	    *clientName = 0, *NetworkAddressToHostname ();

    if (!*accessFile)
	return 1;
    if (type == INDIRECT_QUERY)
	return 1;
    for (d = database; d; d = d->next)
    {
	if (d->hosts)
	    continue;
    	switch (d->type) {
    	case DISPLAY_ALIAS:
	    continue;
    	case DISPLAY_PATTERN:
	    if (!clientName)
		clientName = NetworkAddressToHostname (connectionType,
						       clientAddress);
	    if (!patternMatch (clientName, d->entry.displayPattern))
		continue;
	    break;
    	case DISPLAY_ADDRESS:
	    if (d->entry.displayAddress.connectionType != connectionType ||
	    	!XdmcpARRAY8Equal (&d->entry.displayAddress.clientAddress,
				  clientAddress))
	    {
		continue;
	    }
	    break;
    	}
	break;
    }
    if (clientName)
	free (clientName);
    return (d != 0) && (d->notAllowed == 0);
}

#endif /* XDMCP */