/* 
   Unix SMB/CIFS implementation.
   Password and authentication handling
   Copyright (C) Andrew Bartlett			2002
   Copyright (C) Jelmer Vernooij			2002

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_PASSDB

/* the list of currently registered AUTH backends */
static struct {
	const struct passdb_ops *ops;
} *backends = NULL;
static int num_backends;

/*
  register a AUTH backend. 

  The 'name' can be later used by other backends to find the operations
  structure for this backend.
*/
static NTSTATUS passdb_register(void *_ops)
{
	const struct passdb_ops *ops = _ops;
	struct passdb_ops *new_ops;
	
	if (passdb_backend_byname(ops->name) != NULL) {
		/* its already registered! */
		DEBUG(0,("PASSDB backend '%s' already registered\n", 
			 ops->name));
		return NT_STATUS_OBJECT_NAME_COLLISION;
	}

	backends = Realloc(backends, sizeof(backends[0]) * (num_backends+1));
	if (!backends) {
		smb_panic("out of memory in passdb_register");
	}

	new_ops = smb_xmemdup(ops, sizeof(*ops));
	new_ops->name = smb_xstrdup(ops->name);

	backends[num_backends].ops = new_ops;

	num_backends++;

	DEBUG(3,("PASSDB backend '%s' registered\n", 
		 ops->name));

	return NT_STATUS_OK;
}

/*
  return the operations structure for a named backend of the specified type
*/
const struct passdb_ops *passdb_backend_byname(const char *name)
{
	int i;

	for (i=0;i<num_backends;i++) {
		if (strcmp(backends[i].ops->name, name) == 0) {
			return backends[i].ops;
		}
	}

	return NULL;
}

/*
  return the PASSDB interface version, and the size of some critical types
  This can be used by backends to either detect compilation errors, or provide
  multiple implementations for different smbd compilation options in one module
*/
const struct passdb_critical_sizes *passdb_interface_version(void)
{
	static const struct passdb_critical_sizes critical_sizes = {
		PASSDB_INTERFACE_VERSION,
		sizeof(struct passdb_ops),
		sizeof(struct pdb_methods),
		sizeof(struct pdb_context),
		sizeof(SAM_ACCOUNT)
	};

	return &critical_sizes;
}

/*
  initialise the PASSDB subsystem
*/
BOOL passdb_init(void)
{
	NTSTATUS status;

	status = register_subsystem("passdb", passdb_register); 
	if (!NT_STATUS_IS_OK(status)) {
		return False;
	}

	/* FIXME: Perhaps panic if a basic backend, such as SAM, fails to initialise? */
	static_init_passdb;

	DEBUG(3,("PASSDB subsystem version %d initialised\n", PASSDB_INTERFACE_VERSION));
	return True;
}

static NTSTATUS context_setsampwent(struct pdb_context *context, BOOL update)
{
	NTSTATUS ret = NT_STATUS_UNSUCCESSFUL;

	if (!context) {
		DEBUG(0, ("invalid pdb_context specified!\n"));
		return ret;
	}

	context->pwent_methods = context->pdb_methods;

	if (!context->pwent_methods) {
		/* No passdbs at all */
		return ret;
	}

	while (NT_STATUS_IS_ERR(ret = context->pwent_methods->setsampwent(context->pwent_methods, update))) {
		context->pwent_methods = context->pwent_methods->next;
		if (context->pwent_methods == NULL) 
			return NT_STATUS_UNSUCCESSFUL;
	}
	return ret;
}

static void context_endsampwent(struct pdb_context *context)
{
	if ((!context)){
		DEBUG(0, ("invalid pdb_context specified!\n"));
		return;
	}

	if (context->pwent_methods && context->pwent_methods->endsampwent)
		context->pwent_methods->endsampwent(context->pwent_methods);

	/* So we won't get strange data when calling getsampwent now */
	context->pwent_methods = NULL;
}

static NTSTATUS context_getsampwent(struct pdb_context *context, SAM_ACCOUNT *user)
{
	NTSTATUS ret = NT_STATUS_UNSUCCESSFUL;

	if ((!context) || (!context->pwent_methods)) {
		DEBUG(0, ("invalid pdb_context specified!\n"));
		return ret;
	}
	/* Loop until we find something useful */
	while (NT_STATUS_IS_ERR(ret = context->pwent_methods->getsampwent(context->pwent_methods, user))) {

		context->pwent_methods->endsampwent(context->pwent_methods);

		context->pwent_methods = context->pwent_methods->next;

		/* All methods are checked now. There are no more entries */
		if (context->pwent_methods == NULL)
			return ret;
	
		context->pwent_methods->setsampwent(context->pwent_methods, False);
	}
	user->methods = context->pwent_methods;
	return ret;
}

static NTSTATUS context_getsampwnam(struct pdb_context *context, SAM_ACCOUNT *sam_acct, const char *username)
{
	NTSTATUS ret = NT_STATUS_UNSUCCESSFUL;

	struct pdb_methods *curmethods;
	if ((!context)) {
		DEBUG(0, ("invalid pdb_context specified!\n"));
		return ret;
	}
	curmethods = context->pdb_methods;
	while (curmethods){
		if (NT_STATUS_IS_OK(ret = curmethods->getsampwnam(curmethods, sam_acct, username))) {
			sam_acct->methods = curmethods;
			return ret;
		}
		curmethods = curmethods->next;
	}

	return ret;
}

static NTSTATUS context_getsampwsid(struct pdb_context *context, SAM_ACCOUNT *sam_acct, const DOM_SID *sid)
{
	NTSTATUS ret = NT_STATUS_UNSUCCESSFUL;

	struct pdb_methods *curmethods;
	if ((!context)) {
		DEBUG(0, ("invalid pdb_context specified!\n"));
		return ret;
	}
	
	curmethods = context->pdb_methods;

	while (curmethods){
		if (NT_STATUS_IS_OK(ret = curmethods->getsampwsid(curmethods, sam_acct, sid))) {
			sam_acct->methods = curmethods;
			return ret;
		}
		curmethods = curmethods->next;
	}

	return ret;
}

static NTSTATUS context_add_sam_account(struct pdb_context *context, SAM_ACCOUNT *sam_acct)
{
	NTSTATUS ret = NT_STATUS_UNSUCCESSFUL;

	if ((!context) || (!context->pdb_methods)) {
		DEBUG(0, ("invalid pdb_context specified!\n"));
		return ret;
	}

	/** @todo  This is where a 're-read on add' should be done */
	/* We now add a new account to the first database listed. 
	 * Should we? */

	return context->pdb_methods->add_sam_account(context->pdb_methods, sam_acct);
}

static NTSTATUS context_update_sam_account(struct pdb_context *context, SAM_ACCOUNT *sam_acct)
{
	NTSTATUS ret = NT_STATUS_UNSUCCESSFUL;

	if (!context) {
		DEBUG(0, ("invalid pdb_context specified!\n"));
		return ret;
	}

	if (!sam_acct || !sam_acct->methods){
		DEBUG(0, ("invalid sam_acct specified\n"));
		return ret;
	}

	/** @todo  This is where a 're-read on update' should be done */

	return sam_acct->methods->update_sam_account(sam_acct->methods, sam_acct);
}

static NTSTATUS context_delete_sam_account(struct pdb_context *context, SAM_ACCOUNT *sam_acct)
{
	NTSTATUS ret = NT_STATUS_UNSUCCESSFUL;

	struct pdb_methods *pdb_selected;
	if (!context) {
		DEBUG(0, ("invalid pdb_context specified!\n"));
		return ret;
	}

	if (!sam_acct->methods){
		pdb_selected = context->pdb_methods;
		/* There's no passdb backend specified for this account.
		 * Try to delete it in every passdb available 
		 * Needed to delete accounts in smbpasswd that are not
		 * in /etc/passwd.
		 */
		while (pdb_selected){
			if (NT_STATUS_IS_OK(ret = pdb_selected->delete_sam_account(pdb_selected, sam_acct))) {
				return ret;
			}
			pdb_selected = pdb_selected->next;
		}
		return ret;
	}

	if (!sam_acct->methods->delete_sam_account){
		DEBUG(0,("invalid sam_acct->methods->delete_sam_account\n"));
		return ret;
	}
	
	return sam_acct->methods->delete_sam_account(sam_acct->methods, sam_acct);
}

/******************************************************************
  Free and cleanup a pdb context, any associated data and anything
  that the attached modules might have associated.
 *******************************************************************/

static void free_pdb_context(struct pdb_context **context)
{
	struct pdb_methods *pdb_selected = (*context)->pdb_methods;

	while (pdb_selected){
		if(pdb_selected->free_private_data)
			pdb_selected->free_private_data(&(pdb_selected->private_data));
		pdb_selected = pdb_selected->next;
	}

	talloc_destroy((*context)->mem_ctx);
	*context = NULL;
}

/******************************************************************
  Make a pdb_methods from scratch
 *******************************************************************/

static NTSTATUS make_pdb_methods_name(struct pdb_methods **methods, struct pdb_context *context, const char *selected)
{
	char *module_name = smb_xstrdup(selected);
	char *module_param = NULL, *p;
	const struct passdb_ops *ops;
	NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;

	p = strchr(module_name, ':');

	if (p) {
		*p = 0;
		module_param = p+1;
		trim_string(module_param, " ", " ");
	}

	trim_string(module_name, " ", " ");


	DEBUG(5,("Attempting to find an passdb backend to match %s (%s)\n", selected, module_name));

	ops = passdb_backend_byname(module_name);
	/* No such backend found */
	if(!ops) { 
		SAFE_FREE(module_name);
		return NT_STATUS_INVALID_PARAMETER;
	}
	DEBUG(5,("Found PASSDB backend %s\n", module_name));
	nt_status = ops->init(context, methods, module_param);
	if (NT_STATUS_IS_OK(nt_status)) {
		DEBUG(5,("PASSDB backend %s has a valid init\n", selected));
	} else {
		DEBUG(0,("PASSDB backend %s did not correctly init (error was %s)\n", selected, nt_errstr(nt_status)));
	}
	SAFE_FREE(module_name);
	return nt_status;
}

/******************************************************************
  Make a pdb_context from scratch.
 *******************************************************************/

static NTSTATUS make_pdb_context(struct pdb_context **context) 
{
	TALLOC_CTX *mem_ctx;

	mem_ctx = talloc_init("pdb_context internal allocation context");

	if (!mem_ctx) {
		DEBUG(0, ("make_pdb_context: talloc init failed!\n"));
		return NT_STATUS_NO_MEMORY;
	}		

	*context = talloc(mem_ctx, sizeof(**context));
	if (!*context) {
		DEBUG(0, ("make_pdb_context: talloc failed!\n"));
		return NT_STATUS_NO_MEMORY;
	}

	ZERO_STRUCTP(*context);

	(*context)->mem_ctx = mem_ctx;

	(*context)->pdb_setsampwent = context_setsampwent;
	(*context)->pdb_endsampwent = context_endsampwent;
	(*context)->pdb_getsampwent = context_getsampwent;
	(*context)->pdb_getsampwnam = context_getsampwnam;
	(*context)->pdb_getsampwsid = context_getsampwsid;
	(*context)->pdb_add_sam_account = context_add_sam_account;
	(*context)->pdb_update_sam_account = context_update_sam_account;
	(*context)->pdb_delete_sam_account = context_delete_sam_account;

	(*context)->free_fn = free_pdb_context;

	return NT_STATUS_OK;
}


/******************************************************************
  Make a pdb_context, given an array of strings
 *******************************************************************/

NTSTATUS make_pdb_context_list(struct pdb_context **context, const char **selected) 
{
	int i = 0;
	struct pdb_methods *curmethods;
	NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;

	if (!NT_STATUS_IS_OK(nt_status = make_pdb_context(context))) {
		return nt_status;
	}

	while (selected[i]){
		/* Try to initialise pdb */
		DEBUG(5,("Trying to load: %s\n", selected[i]));
		if (!NT_STATUS_IS_OK(nt_status = make_pdb_methods_name(&curmethods, *context, selected[i]))) {
			DEBUG(1, ("Loading %s failed!\n", selected[i]));
			free_pdb_context(context);
			return nt_status;
		}
		curmethods->parent = *context;
		DLIST_ADD_END((*context)->pdb_methods, curmethods, struct pdb_methods *);
		i++;
	}

	return NT_STATUS_OK;
}

/******************************************************************
  Make a pdb_context, given a text string.
 *******************************************************************/

NTSTATUS make_pdb_context_string(struct pdb_context **context, const char *selected) 
{
	NTSTATUS ret;
	char **newsel = str_list_make(selected, NULL);
	ret = make_pdb_context_list(context, (const char **)newsel);
	str_list_free(&newsel);
	return ret;
}

/******************************************************************
 Return an already initialised pdb_context, to facilitate backward 
 compatibility (see functions below).
*******************************************************************/

static struct pdb_context *pdb_get_static_context(BOOL reload) 
{
	static struct pdb_context *pdb_context = NULL;

	if ((pdb_context) && (reload)) {
		pdb_context->free_fn(&pdb_context);
		if (NT_STATUS_IS_ERR(make_pdb_context_list(&pdb_context, lp_passdb_backend()))) {
			return NULL;
		}
	}

	if (!pdb_context) {
		if (NT_STATUS_IS_ERR(make_pdb_context_list(&pdb_context, lp_passdb_backend()))) {
			return NULL;
		}
	}

	return pdb_context;
}

/******************************************************************
 Backward compatibility functions for the original passdb interface
*******************************************************************/

BOOL pdb_setsampwent(BOOL update) 
{
	struct pdb_context *pdb_context = pdb_get_static_context(False);

	if (!pdb_context) {
		return False;
	}

	return NT_STATUS_IS_OK(pdb_context->pdb_setsampwent(pdb_context, update));
}

void pdb_endsampwent(void) 
{
	struct pdb_context *pdb_context = pdb_get_static_context(False);

	if (!pdb_context) {
		return;
	}

	pdb_context->pdb_endsampwent(pdb_context);
}

BOOL pdb_getsampwent(SAM_ACCOUNT *user) 
{
	struct pdb_context *pdb_context = pdb_get_static_context(False);

	if (!pdb_context) {
		return False;
	}

	return NT_STATUS_IS_OK(pdb_context->pdb_getsampwent(pdb_context, user));
}

BOOL pdb_getsampwnam(SAM_ACCOUNT *sam_acct, const char *username) 
{
	struct pdb_context *pdb_context = pdb_get_static_context(False);

	if (!pdb_context) {
		return False;
	}

	return NT_STATUS_IS_OK(pdb_context->pdb_getsampwnam(pdb_context, sam_acct, username));
}

BOOL pdb_getsampwsid(SAM_ACCOUNT *sam_acct, const DOM_SID *sid) 
{
	struct pdb_context *pdb_context = pdb_get_static_context(False);

	if (!pdb_context) {
		return False;
	}

	return NT_STATUS_IS_OK(pdb_context->pdb_getsampwsid(pdb_context, sam_acct, sid));
}

BOOL pdb_add_sam_account(SAM_ACCOUNT *sam_acct) 
{
	struct pdb_context *pdb_context = pdb_get_static_context(False);

	if (!pdb_context) {
		return False;
	}

	return NT_STATUS_IS_OK(pdb_context->pdb_add_sam_account(pdb_context, sam_acct));
}

BOOL pdb_update_sam_account(SAM_ACCOUNT *sam_acct) 
{
	struct pdb_context *pdb_context = pdb_get_static_context(False);

	if (!pdb_context) {
		return False;
	}

	return NT_STATUS_IS_OK(pdb_context->pdb_update_sam_account(pdb_context, sam_acct));
}

BOOL pdb_delete_sam_account(SAM_ACCOUNT *sam_acct) 
{
	struct pdb_context *pdb_context = pdb_get_static_context(False);

	if (!pdb_context) {
		return False;
	}

	return NT_STATUS_IS_OK(pdb_context->pdb_delete_sam_account(pdb_context, sam_acct));
}

/***************************************************************
  Initialize the static context (at smbd startup etc). 

  If uninitialised, context will auto-init on first use.
 ***************************************************************/

BOOL initialize_password_db(BOOL reload)
{	
	return (pdb_get_static_context(reload) != NULL);
}


/***************************************************************************
  Default implementations of some functions.
 ****************************************************************************/

static NTSTATUS pdb_default_getsampwnam (struct pdb_methods *methods, SAM_ACCOUNT *user, const char *sname)
{
	return NT_STATUS_NO_SUCH_USER;
}

static NTSTATUS pdb_default_getsampwsid(struct pdb_methods *my_methods, SAM_ACCOUNT * user, const DOM_SID *sid)
{
	return NT_STATUS_NO_SUCH_USER;
}

static NTSTATUS pdb_default_add_sam_account (struct pdb_methods *methods, SAM_ACCOUNT *newpwd)
{
	DEBUG(0,("this backend (%s) should not be listed as the first passdb backend! You can't add users to it.\n", methods->name));
	return NT_STATUS_NOT_IMPLEMENTED;
}

static NTSTATUS pdb_default_update_sam_account (struct pdb_methods *methods, SAM_ACCOUNT *newpwd)
{
	return NT_STATUS_NOT_IMPLEMENTED;
}

static NTSTATUS pdb_default_delete_sam_account (struct pdb_methods *methods, SAM_ACCOUNT *pwd)
{
	return NT_STATUS_NOT_IMPLEMENTED;
}

static NTSTATUS pdb_default_setsampwent(struct pdb_methods *methods, BOOL update)
{
	return NT_STATUS_NOT_IMPLEMENTED;
}

static NTSTATUS pdb_default_getsampwent(struct pdb_methods *methods, SAM_ACCOUNT *user)
{
	return NT_STATUS_NOT_IMPLEMENTED;
}

static void pdb_default_endsampwent(struct pdb_methods *methods)
{
	return; /* NT_STATUS_NOT_IMPLEMENTED; */
}

NTSTATUS make_pdb_methods(TALLOC_CTX *mem_ctx, PDB_METHODS **methods) 
{
	*methods = talloc(mem_ctx, sizeof(struct pdb_methods));

	if (!*methods) {
		return NT_STATUS_NO_MEMORY;
	}

	ZERO_STRUCTP(*methods);

	(*methods)->setsampwent = pdb_default_setsampwent;
	(*methods)->endsampwent = pdb_default_endsampwent;
	(*methods)->getsampwent = pdb_default_getsampwent;
	(*methods)->getsampwnam = pdb_default_getsampwnam;
	(*methods)->getsampwsid = pdb_default_getsampwsid;
	(*methods)->add_sam_account = pdb_default_add_sam_account;
	(*methods)->update_sam_account = pdb_default_update_sam_account;
	(*methods)->delete_sam_account = pdb_default_delete_sam_account;

	return NT_STATUS_OK;
}