/*	$OpenBSD: table_db.c,v 1.5 2013/05/24 17:03:14 eric Exp $	*/

/*
 * Copyright (c) 2011 Gilles Chehade <gilles@poolp.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/queue.h>
#include <sys/tree.h>
#include <sys/socket.h>

#include <netinet/in.h>
#include <arpa/inet.h>

#include <db.h>
#include <ctype.h>
#include <err.h>
#include <event.h>
#include <fcntl.h>
#include <imsg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "smtpd.h"
#include "log.h"


/* db(3) backend */
static int table_db_config(struct table *);
static int table_db_update(struct table *);
static void *table_db_open(struct table *);
static int table_db_lookup(void *, const char *, enum table_service, union lookup *);
static int table_db_fetch(void *, enum table_service, union lookup *);
static void  table_db_close(void *);

static char *table_db_get_entry(void *, const char *, size_t *);
static char *table_db_get_entry_match(void *, const char *, size_t *,
    int(*)(const char *, const char *));

struct table_backend table_backend_db = {
	K_ALIAS|K_CREDENTIALS|K_DOMAIN|K_NETADDR|K_USERINFO|K_SOURCE|K_ADDRNAME,
	table_db_config,
	table_db_open,
	table_db_update,
	table_db_close,
	table_db_lookup,
	table_db_fetch,
};

static struct keycmp {
	enum table_service	service;
	int		       (*func)(const char *, const char *);
} keycmp[] = {
	{ K_DOMAIN, table_domain_match },
	{ K_NETADDR, table_netaddr_match }
};

struct dbhandle {
	DB		*db;
	char		 pathname[SMTPD_MAXPATHLEN];
	time_t		 mtime;
	struct table	*table;
};

static int
table_db_config(struct table *table)
{
	struct dbhandle	       *handle;

	handle = table_db_open(table);
	if (handle == NULL)
		return 0;

	table_db_close(handle);
	return 1;
}

static int
table_db_update(struct table *table)
{
	struct dbhandle	*handle;

	handle = table_db_open(table);
	if (handle == NULL)
		return 0;

	table_db_close(table->t_handle);
	table->t_handle = handle;
	return 1;
}

static void *
table_db_open(struct table *table)
{
	struct dbhandle	       *handle;
	struct stat		sb;

	handle = xcalloc(1, sizeof *handle, "table_db_open");
	if (strlcpy(handle->pathname, table->t_config, sizeof handle->pathname)
	    >= sizeof handle->pathname)
		goto error;

	if (stat(handle->pathname, &sb) < 0)
		goto error;

	handle->mtime = sb.st_mtime;
	handle->db = dbopen(table->t_config, O_RDONLY, 0600, DB_HASH, NULL);
	if (handle->db == NULL)
		goto error;
	handle->table = table;

	return handle;

error:
	if (handle->db)
		handle->db->close(handle->db);
	free(handle);
	return NULL;
}

static void
table_db_close(void *hdl)
{
	struct dbhandle	*handle = hdl;
	handle->db->close(handle->db);
	free(handle);
}

static int
table_db_lookup(void *hdl, const char *key, enum table_service service,
    union lookup *lk)
{
	struct dbhandle	*handle = hdl;
	struct table	*table = NULL;
	char	       *line;
	size_t		len = 0;
	int		ret;
	int	       (*match)(const char *, const char *) = NULL;
	size_t		i;
	struct stat	sb;

	if (stat(handle->pathname, &sb) < 0)
		return -1;

	/* DB has changed, close and reopen */
	if (sb.st_mtime != handle->mtime) {
		table = handle->table;
		table_db_update(handle->table);
		handle = table->t_handle;
	}

	for (i = 0; i < nitems(keycmp); ++i)
		if (keycmp[i].service == service)
			match = keycmp[i].func;

	if (match == NULL)
		line = table_db_get_entry(handle, key, &len);
	else
		line = table_db_get_entry_match(handle, key, &len, match);
	if (line == NULL)
		return 0;

	ret = 1;
	if (lk)
		ret = table_parse_lookup(service, key, line, lk);
	free(line);

	return ret;
}

static int
table_db_fetch(void *hdl, enum table_service service, union lookup *lk)
{
	struct dbhandle	*handle = hdl;
	struct table	*table  = handle->table;
	DBT dbk;
	DBT dbd;
	int r;

	if (table->t_iter == NULL)
		r = handle->db->seq(handle->db, &dbk, &dbd, R_FIRST);
	else
		r = handle->db->seq(handle->db, &dbk, &dbd, R_NEXT);
	table->t_iter = handle->db;
	if (!r) {
		r = handle->db->seq(handle->db, &dbk, &dbd, R_FIRST);
		if (!r)
			return 0;
	}

	return table_parse_lookup(service, NULL, dbk.data, lk);
}


static char *
table_db_get_entry_match(void *hdl, const char *key, size_t *len,
    int(*func)(const char *, const char *))
{
	struct dbhandle	*handle = hdl;
	DBT dbk;
	DBT dbd;
	int r;
	char *buf = NULL;

	for (r = handle->db->seq(handle->db, &dbk, &dbd, R_FIRST); !r;
	     r = handle->db->seq(handle->db, &dbk, &dbd, R_NEXT)) {
		buf = xmemdup(dbk.data, dbk.size, "table_db_get_entry_cmp");
		if (func(key, buf)) {
			*len = dbk.size;
			return buf;
		}
		free(buf);
	}
	return NULL;
}

static char *
table_db_get_entry(void *hdl, const char *key, size_t *len)
{
	struct dbhandle	*handle = hdl;
	int ret;
	DBT dbk;
	DBT dbv;
	char pkey[SMTPD_MAXLINESIZE];

	/* workaround the stupidity of the DB interface */
	if (strlcpy(pkey, key, sizeof pkey) >= sizeof pkey)
		errx(1, "table_db_get_entry: key too long");
	dbk.data = pkey;
	dbk.size = strlen(pkey) + 1;

	if ((ret = handle->db->get(handle->db, &dbk, &dbv, 0)) != 0)
		return NULL;

	*len = dbv.size;

	return xmemdup(dbv.data, dbv.size, "table_db_get_entry");
}