/* 
   Unix SMB/CIFS implementation.
   Idmap NSS headers

   Copyright (C) Gerald Carter             2006

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.
   
   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.
   
   You should have received a copy of the GNU Library General Public
   License along with this library; if not, write to the
   Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA  02111-1307, USA.   
*/

#include "includes.h"
#include "nss_info.h"

static struct nss_function_entry *backends = NULL;
static struct nss_domain_entry *nss_domain_list = NULL;

/**********************************************************************
 Get idmap nss methods.
**********************************************************************/

static struct nss_function_entry *nss_get_backend(const char *name )
{
	struct nss_function_entry *entry = backends;

	for(entry = backends; entry; entry = entry->next) {
		if ( strequal(entry->name, name) )
			return entry;
	}

	return NULL;
}

/*********************************************************************
 Allow a module to register itself as a backend.
**********************************************************************/

 NTSTATUS smb_register_idmap_nss(int version, const char *name, struct nss_info_methods *methods)
{
	struct nss_function_entry *entry;

 	if ((version != SMB_NSS_INFO_INTERFACE_VERSION)) {
		DEBUG(0, ("smb_register_idmap_nss: Failed to register idmap_nss module.\n"
		          "The module was compiled against SMB_NSS_INFO_INTERFACE_VERSION %d,\n"
		          "current SMB_NSS_INFO_INTERFACE_VERSION is %d.\n"
		          "Please recompile against the current version of samba!\n",  
			  version, SMB_NSS_INFO_INTERFACE_VERSION));
		return NT_STATUS_OBJECT_TYPE_MISMATCH;
  	}

	if (!name || !name[0] || !methods) {
		DEBUG(0,("smb_register_idmap_nss: called with NULL pointer or empty name!\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}

	if ( nss_get_backend(name) ) {
		DEBUG(0,("smb_register_idmap_nss: idmap module %s "
			 "already registered!\n", name));
		return NT_STATUS_OBJECT_NAME_COLLISION;
	}

	entry = SMB_XMALLOC_P(struct nss_function_entry);
	entry->name = smb_xstrdup(name);
	entry->methods = methods;

	DLIST_ADD(backends, entry);
	DEBUG(5, ("smb_register_idmap_nss: Successfully added idmap "
		  "nss backend '%s'\n", name));

	return NT_STATUS_OK;
}

/********************************************************************
 *******************************************************************/

static BOOL parse_nss_parm( const char *config, char **backend, char **domain )
{
	char *p;
	char *q;
	int len;

	*backend = *domain = NULL;
	
	if ( !config )
		return False;
	
	p = strchr( config, ':' );
	
	/* if no : then the string must be the backend name only */

	if ( !p ) {
		*backend = SMB_STRDUP( config );
		return (*backend != NULL);
	}

	/* split the string and return the two parts */

	if ( strlen(p+1) > 0 ) {
		*domain = SMB_STRDUP( p+1 );
	}
	
	len = PTR_DIFF(p,config)+1;
	if ( (q = SMB_MALLOC_ARRAY( char, len )) == NULL ) {
		SAFE_FREE( *backend );
		return False;
	}
	
	StrnCpy( q, config, len-1);
	q[len-1] = '\0';
	*backend = q;

	return True;
}

/********************************************************************
 Each nss backend must not store global state, but rather be able 
 to initialize the state on a per domain basis.
 *******************************************************************/

 NTSTATUS nss_init( const char **nss_list )
{
	NTSTATUS status;
	static NTSTATUS nss_initialized = NT_STATUS_UNSUCCESSFUL;
	int i;
	char *backend, *domain;
	struct nss_function_entry *nss_backend;
	struct nss_domain_entry *nss_domain;

	/* check for previous successful initializations */

	if ( NT_STATUS_IS_OK(nss_initialized) )
		return NT_STATUS_OK;
	
	/* The "template" backend should alqays be registered as it
	   is a static module */

	if ( (nss_backend = nss_get_backend( "template" )) == NULL ) {
		static_init_nss_info;	       
	}

	/* Create the list of nss_domains (loading any shared plugins
	   as necessary) */

	for ( i=0; nss_list && nss_list[i]; i++ ) {

		if ( !parse_nss_parm(nss_list[i], &backend, &domain) ) 	{
			DEBUG(0,("nss_init: failed to parse \"%s\"!\n",
				 nss_list[i]));
			continue;			
		}

		/* validate the backend */

		if ( (nss_backend = nss_get_backend( backend )) == NULL ) {
			/* attempt to register the backend */
			status = smb_probe_module( "nss_info", backend );
			if ( !NT_STATUS_IS_OK(status) ) {
				continue;
			}
			
			/* try again */
			if ( (nss_backend = nss_get_backend( backend )) == NULL ) {
				DEBUG(0,("nss_init: unregistered backend %s!.  Skipping\n",
					 backend));
				continue;
			}

		}

     		/* fill in the nss_domain_entry and add it to the 
		   list of domains */

		nss_domain = TALLOC_ZERO_P( nss_domain_list, struct nss_domain_entry );
		if ( !nss_domain ) {
			DEBUG(0,("nss_init: talloc() failure!\n"));
			return NT_STATUS_NO_MEMORY;
		}
		
		nss_domain->backend = nss_backend;
		nss_domain->domain  = talloc_strdup( nss_domain, domain );

		status = nss_domain->backend->methods->init( nss_domain );
		if ( NT_STATUS_IS_OK( status ) ) {
			DLIST_ADD( nss_domain_list, nss_domain );
		} else {
			DEBUG(0,("nss_init: Failed to init backend for %s domain!\n", 
				 nss_domain->domain));
		}

		/* cleanup */

		SAFE_FREE( backend );
		SAFE_FREE( domain );		
	}

	if ( !nss_domain_list ) {
		DEBUG(3,("nss_init: no nss backends configured.  "
			 "Defaulting to \"template\".\n"));


		/* we shouild default to use template here */
	}
	
		
	nss_initialized = NT_STATUS_OK;
	
	return NT_STATUS_OK;
}

/********************************************************************
 *******************************************************************/

static struct nss_domain_entry *find_nss_domain( const char *domain )
{
	NTSTATUS status;	
	struct nss_domain_entry *p;

	status = nss_init( lp_winbind_nss_info() );
	if ( !NT_STATUS_IS_OK(status) ) {
		DEBUG(4,("nss_get_info: Failed to init nss_info API (%s)!\n",
			 nt_errstr(status)));
		return NULL;
	}
	
	for ( p=nss_domain_list; p; p=p->next ) {
		if ( strequal( p->domain, domain ) )
			break;
	}
	
	/* If we didn't find a match, then use the default nss info */

	if ( !p ) {
		if ( !nss_domain_list ) {
			return NULL;
		}
		
		p = nss_domain_list;		
	}

	return p;
}

/********************************************************************
 *******************************************************************/

 NTSTATUS nss_get_info( const char *domain, const DOM_SID *user_sid,
		       TALLOC_CTX *ctx,
		       ADS_STRUCT *ads, LDAPMessage *msg,
		       char **homedir, char **shell, char **gecos,
		       gid_t *p_gid)
{
	struct nss_domain_entry *p;
	struct nss_info_methods *m;

	if ( (p = find_nss_domain( domain )) == NULL ) {
		DEBUG(4,("nss_get_info: Failed to find nss domain pointer for %s\n",
			 domain ));
		return NT_STATUS_NOT_FOUND;
	}
		
	m = p->backend->methods;

	return m->get_nss_info( p, user_sid, ctx, ads, msg, 
				homedir, shell, gecos, p_gid );
}

/********************************************************************
 *******************************************************************/

 NTSTATUS nss_close( const char *parameters )
{
	struct nss_domain_entry *p = nss_domain_list;
	struct nss_domain_entry *q;

	while ( p && p->backend && p->backend->methods ) {
		/* close the backend */
		p->backend->methods->close_fn();

		/* free the memory */
		q = p;
		p = p->next;
		TALLOC_FREE( q );
	}

	return NT_STATUS_OK;
}