/*
  * Stores channel settings for +P channels in a .db file
  * (C) Copyright 2019 Syzop, Gottem and the UnrealIRCd team
  * License: GPLv2 or later
  */
 
 #include "unrealircd.h"
 
 ModuleHeader MOD_HEADER = {
 	"channeldb",
 	"1.0",
 	"Stores and retrieves channel settings for persistent (+P) channels",
 	"UnrealIRCd Team",
 	"unrealircd-6",
 };
 
 /* Database version */
 #define CHANNELDB_VERSION 100
 /* Save channels to file every <this> seconds */
 #define CHANNELDB_SAVE_EVERY 300
 /* The very first save after boot, apply this delta, this
  * so we don't coincide with other (potentially) expensive
  * I/O events like saving tkldb.
  */
 #define CHANNELDB_SAVE_EVERY_DELTA -15
 
 #define MAGIC_CHANNEL_START	0x11111111
 #define MAGIC_CHANNEL_END	0x22222222
 
 // #undef BENCHMARK
 
 #define WARN_WRITE_ERROR(fname) \
 	do { \
 		unreal_log(ULOG_ERROR, "channeldb", "CHANNELDB_FILE_WRITE_ERROR", NULL, \
 			   "[channeldb] Error writing to temporary database file $filename: $system_error", \
 			   log_data_string("filename", fname), \
 			   log_data_string("system_error", unrealdb_get_error_string())); \
 	} while(0)
 
 #define W_SAFE(x) \
 	do { \
 		if (!(x)) { \
 			WARN_WRITE_ERROR(tmpfname); \
 			unrealdb_close(db); \
 			return 0; \
 		} \
 	} while(0)
 
 #define IsMDErr(x, y, z) \
 	do { \
 		if (!(x)) { \
 			config_error("A critical error occurred when registering ModData for %s: %s", MOD_HEADER.name, ModuleGetErrorStr((z)->handle)); \
 			return MOD_FAILED; \
 		} \
 	} while(0)
 
 /* Structs */
 struct cfgstruct {
 	char *database;
 	char *db_secret;
 };
 
 /* Forward declarations */
 void channeldb_moddata_free(ModData *md);
 void setcfg(struct cfgstruct *cfg);
 void freecfg(struct cfgstruct *cfg);
 int channeldb_config_test(ConfigFile *cf, ConfigEntry *ce, int type, int *errs);
 int channeldb_config_posttest(int *errs);
 int channeldb_config_run(ConfigFile *cf, ConfigEntry *ce, int type);
 EVENT(write_channeldb_evt);
 int write_channeldb(void);
 int write_channel_entry(UnrealDB *db, const char *tmpfname, Channel *channel);
 int read_channeldb(void);
 
 /* Global variables */
 static uint32_t channeldb_version = CHANNELDB_VERSION;
 static struct cfgstruct cfg;
 static struct cfgstruct test;
 
 static long channeldb_next_event = 0;
 
 MOD_TEST()
 {
 	memset(&cfg, 0, sizeof(cfg));
 	memset(&test, 0, sizeof(test));
 	setcfg(&test);
 	HookAdd(modinfo->handle, HOOKTYPE_CONFIGTEST, 0, channeldb_config_test);
 	HookAdd(modinfo->handle, HOOKTYPE_CONFIGPOSTTEST, 0, channeldb_config_posttest);
 	return MOD_SUCCESS;
 }
 
 MOD_INIT()
 {
 	MARK_AS_OFFICIAL_MODULE(modinfo);
 	/* We must unload early, when all channel modes and such are still in place: */
 	ModuleSetOptions(modinfo->handle, MOD_OPT_PRIORITY, -99999999);
 
 	LoadPersistentLong(modinfo, channeldb_next_event);
 
 	setcfg(&cfg);
 
 	HookAdd(modinfo->handle, HOOKTYPE_CONFIGRUN, 0, channeldb_config_run);
 	return MOD_SUCCESS;
 }
 
 MOD_LOAD()
 {
 	if (!channeldb_next_event)
 	{
 		/* If this is the first time that our module is loaded, then read the database. */
 		if (!read_channeldb())
 		{
 			char fname[512];
 			snprintf(fname, sizeof(fname), "%s.corrupt", cfg.database);
 			if (rename(cfg.database, fname) == 0)
 				config_warn("[channeldb] Existing database renamed to %s and starting a new one...", fname);
 			else
 				config_warn("[channeldb] Failed to rename database from %s to %s: %s", cfg.database, fname, strerror(errno));
 		}
 		channeldb_next_event = TStime() + CHANNELDB_SAVE_EVERY + CHANNELDB_SAVE_EVERY_DELTA;
 	}
 	EventAdd(modinfo->handle, "channeldb_write_channeldb", write_channeldb_evt, NULL, 1000, 0);
 	if (ModuleGetError(modinfo->handle) != MODERR_NOERROR)
 	{
 		config_error("A critical error occurred when loading module %s: %s", MOD_HEADER.name, ModuleGetErrorStr(modinfo->handle));
 		return MOD_FAILED;
 	}
 	return MOD_SUCCESS;
 }
 
 MOD_UNLOAD()
 {
 	if (loop.terminating)
 		write_channeldb();
 	freecfg(&test);
 	freecfg(&cfg);
 	SavePersistentLong(modinfo, channeldb_next_event);
 	return MOD_SUCCESS;
 }
 
 void channeldb_moddata_free(ModData *md)
 {
 	if (md->i)
 		md->i = 0;
 }
 
 void setcfg(struct cfgstruct *cfg)
 {
 	// Default: data/channel.db
 	safe_strdup(cfg->database, "channel.db");
 	convert_to_absolute_path(&cfg->database, PERMDATADIR);
 }
 
 void freecfg(struct cfgstruct *cfg)
 {
 	safe_free(cfg->database);
 	safe_free(cfg->db_secret);
 }
 
 int channeldb_config_test(ConfigFile *cf, ConfigEntry *ce, int type, int *errs)
 {
 	int errors = 0;
 	ConfigEntry *cep;
 
 	// We are only interested in set::channeldb::database
 	if (type != CONFIG_SET)
 		return 0;
 
 	if (!ce || strcmp(ce->name, "channeldb"))
 		return 0;
 
 	for (cep = ce->items; cep; cep = cep->next)
 	{
 		if (!cep->value)
 		{
 			config_error("%s:%i: blank set::channeldb::%s without value", cep->file->filename, cep->line_number, cep->name);
 			errors++;
 		} else
 		if (!strcmp(cep->name, "database"))
 		{
 			convert_to_absolute_path(&cep->value, PERMDATADIR);
 			safe_strdup(test.database, cep->value);
 		} else
 		if (!strcmp(cep->name, "db-secret"))
 		{
 			const char *err;
 			if ((err = unrealdb_test_secret(cep->value)))
 			{
 				config_error("%s:%i: set::channeldb::db-secret: %s", cep->file->filename, cep->line_number, err);
 				errors++;
 				continue;
 			}
 			safe_strdup(test.db_secret, cep->value);
 		} else
 		{
 			config_error("%s:%i: unknown directive set::channeldb::%s", cep->file->filename, cep->line_number, cep->name);
 			errors++;
 		}
 	}
 
 	*errs = errors;
 	return errors ? -1 : 1;
 }
 
 int channeldb_config_posttest(int *errs)
 {
 	int errors = 0;
 	char *errstr;
 
 	if (test.database && ((errstr = unrealdb_test_db(test.database, test.db_secret))))
 	{
 		config_error("[channeldb] %s", errstr);
 		errors++;
 	}
 
 	*errs = errors;
 	return errors ? -1 : 1;
 }
 
 int channeldb_config_run(ConfigFile *cf, ConfigEntry *ce, int type)
 {
 	ConfigEntry *cep;
 
 	// We are only interested in set::channeldb::database
 	if (type != CONFIG_SET)
 		return 0;
 
 	if (!ce || strcmp(ce->name, "channeldb"))
 		return 0;
 
 	for (cep = ce->items; cep; cep = cep->next)
 	{
 		if (!strcmp(cep->name, "database"))
 			safe_strdup(cfg.database, cep->value);
 		else if (!strcmp(cep->name, "db-secret"))
 			safe_strdup(cfg.db_secret, cep->value);
 	}
 	return 1;
 }
 
 EVENT(write_channeldb_evt)
 {
 	if (channeldb_next_event > TStime())
 		return;
 	channeldb_next_event = TStime() + CHANNELDB_SAVE_EVERY;
 	write_channeldb();
 }
 
 int write_channeldb(void)
 {
 	char tmpfname[512];
 	UnrealDB *db;
 	Channel *channel;
 	int cnt = 0;
 #ifdef BENCHMARK
 	struct timeval tv_alpha, tv_beta;
 
 	gettimeofday(&tv_alpha, NULL);
 #endif
 
 	// Write to a tempfile first, then rename it if everything succeeded
 	snprintf(tmpfname, sizeof(tmpfname), "%s.%x.tmp", cfg.database, getrandom32());
 	db = unrealdb_open(tmpfname, UNREALDB_MODE_WRITE, cfg.db_secret);
 	if (!db)
 	{
 		WARN_WRITE_ERROR(tmpfname);
 		return 0;
 	}
 
 	W_SAFE(unrealdb_write_int32(db, channeldb_version));
 
 	/* First, count +P channels and write the count to the database */
 	for (channel = channels; channel; channel=channel->nextch)
 		if (has_channel_mode(channel, 'P'))
 			cnt++;
 	W_SAFE(unrealdb_write_int64(db, cnt));
 
 	for (channel = channels; channel; channel=channel->nextch)
 	{
 		/* We only care about +P (persistent) channels */
 		if (has_channel_mode(channel, 'P'))
 		{
 			if (!write_channel_entry(db, tmpfname, channel))
 				return 0;
 		}
 	}
 
 	// Everything seems to have gone well, attempt to close and rename the tempfile
 	if (!unrealdb_close(db))
 	{
 		WARN_WRITE_ERROR(tmpfname);
 		return 0;
 	}
 
 #ifdef _WIN32
 	/* The rename operation cannot be atomic on Windows as it will cause a "file exists" error */
 	unlink(cfg.database);
 #endif
 	if (rename(tmpfname, cfg.database) < 0)
 	{
 		config_error("[channeldb] Error renaming '%s' to '%s': %s (DATABASE NOT SAVED)", tmpfname, cfg.database, strerror(errno));
 		return 0;
 	}
 #ifdef BENCHMARK
 	gettimeofday(&tv_beta, NULL);
 	config_status("[channeldb] Benchmark: SAVE DB: %ld microseconds",
 		((tv_beta.tv_sec - tv_alpha.tv_sec) * 1000000) + (tv_beta.tv_usec - tv_alpha.tv_usec));
 #endif
 	return 1;
 }
 
 int write_listmode(UnrealDB *db, const char *tmpfname, Ban *lst)
 {
 	Ban *l;
 	int cnt = 0;
 
 	/* First count and write the list count */
 	for (l = lst; l; l = l->next)
 		cnt++;
 	W_SAFE(unrealdb_write_int32(db, cnt));
 
 	for (l = lst; l; l = l->next)
 	{
 		/* The entry, setby, seton */
 		W_SAFE(unrealdb_write_str(db, l->banstr));
 		W_SAFE(unrealdb_write_str(db, l->who));
 		W_SAFE(unrealdb_write_int64(db, l->when));
 	}
 	return 1;
 }
 
 int write_channel_entry(UnrealDB *db, const char *tmpfname, Channel *channel)
 {
 	char modebuf[BUFSIZE], parabuf[BUFSIZE];
 
 	W_SAFE(unrealdb_write_int32(db, MAGIC_CHANNEL_START));
 	/* Channel name */
 	W_SAFE(unrealdb_write_str(db, channel->name));
 	/* Channel creation time */
 	W_SAFE(unrealdb_write_int64(db, channel->creationtime));
 	/* Topic (topic, setby, seton) */
 	W_SAFE(unrealdb_write_str(db, channel->topic));
 	W_SAFE(unrealdb_write_str(db, channel->topic_nick));
 	W_SAFE(unrealdb_write_int64(db, channel->topic_time));
 	/* Basic channel modes (eg: +sntkl key 55) */
 	channel_modes(&me, modebuf, parabuf, sizeof(modebuf), sizeof(parabuf), channel, 1);
 	W_SAFE(unrealdb_write_str(db, modebuf));
 	W_SAFE(unrealdb_write_str(db, parabuf));
 	/* Mode lock */
 	W_SAFE(unrealdb_write_str(db, channel->mode_lock));
 	/* List modes (bans, exempts, invex) */
 	if (!write_listmode(db, tmpfname, channel->banlist))
 		return 0;
 	if (!write_listmode(db, tmpfname, channel->exlist))
 		return 0;
 	if (!write_listmode(db, tmpfname, channel->invexlist))
 		return 0;
 	W_SAFE(unrealdb_write_int32(db, MAGIC_CHANNEL_END));
 	return 1;
 }
 
 #define R_SAFE(x) \
 	do { \
 		if (!(x)) { \
 			config_warn("[channeldb] Read error from database file '%s' (possible corruption): %s", cfg.database, unrealdb_get_error_string()); \
 			if (e) \
 			{ \
 				safe_free(e->banstr); \
 				safe_free(e->who); \
 				safe_free(e); \
 			} \
 			return 0; \
 		} \
 	} while(0)
 
 int read_listmode(UnrealDB *db, Ban **lst)
 {
 	uint32_t total;
 	uint64_t when;
 	int i;
 	Ban *e = NULL;
 
 	R_SAFE(unrealdb_read_int32(db, &total));
 
 	for (i = 0; i < total; i++)
 	{
 		const char *str;
 		e = safe_alloc(sizeof(Ban));
 		R_SAFE(unrealdb_read_str(db, &e->banstr));
 		R_SAFE(unrealdb_read_str(db, &e->who));
 		R_SAFE(unrealdb_read_int64(db, &when));
 		str = clean_ban_mask(e->banstr, MODE_ADD, &me, 0);
 		if (str == NULL)
 		{
 			/* Skip this item */
 			config_warn("[channeldb] listmode skipped (no longer valid?): %s", e->banstr);
 			safe_free(e->banstr);
 			safe_free(e->who);
 			safe_free(e);
 			continue;
 		}
 		safe_strdup(e->banstr, str);
 
 		if (ban_exists(*lst, e->banstr))
 		{
 			/* Free again - duplicate item */
 			safe_free(e->banstr);
 			safe_free(e->who);
 			safe_free(e);
 		} else {
 			/* Add to list */
 			e->when = when;
 			e->next = *lst;
 			*lst = e;
 		}
 	}
 
 	return 1;
 }
 #undef R_SAFE
 
 #define FreeChannelEntry() \
  	do { \
 		/* Some of these might be NULL */ \
 		safe_free(chname); \
 		safe_free(topic); \
 		safe_free(topic_nick); \
 		safe_free(modes1); \
 		safe_free(modes2); \
 		safe_free(mode_lock); \
 	} while(0)
 
 #define R_SAFE(x) \
 	do { \
 		if (!(x)) { \
 			config_warn("[channeldb] Read error from database file '%s' (possible corruption): %s", cfg.database, unrealdb_get_error_string()); \
 			unrealdb_close(db); \
 			FreeChannelEntry(); \
 			return 0; \
 		} \
 	} while(0)
 
 int read_channeldb(void)
 {
 	UnrealDB *db;
 	uint32_t version;
 	int added = 0;
 	int i;
 	uint64_t count = 0;
 	uint32_t magic;
 	// Variables for the channels
 	// Some of them need to be declared and NULL initialised early due to the macro FreeChannelEntry() being used by R_SAFE() on error
 	char *chname = NULL;
 	uint64_t creationtime = 0;
 	char *topic = NULL;
 	char *topic_nick = NULL;
 	uint64_t topic_time = 0;
 	char *modes1 = NULL;
 	char *modes2 = NULL;
 	char *mode_lock = NULL;
 #ifdef BENCHMARK
 	struct timeval tv_alpha, tv_beta;
 
 	gettimeofday(&tv_alpha, NULL);
 #endif
 
 	db = unrealdb_open(cfg.database, UNREALDB_MODE_READ, cfg.db_secret);
 	if (!db)
 	{
 		if (unrealdb_get_error_code() == UNREALDB_ERROR_FILENOTFOUND)
 		{
 			/* Database does not exist. Could be first boot */
 			config_warn("[channeldb] No database present at '%s', will start a new one", cfg.database);
 			return 1;
 		} else
 		if (unrealdb_get_error_code() == UNREALDB_ERROR_NOTCRYPTED)
 		{
 			/* Re-open as unencrypted */
 			db = unrealdb_open(cfg.database, UNREALDB_MODE_READ, NULL);
 			if (!db)
 			{
 				/* This should actually never happen, unless some weird I/O error */
 				config_warn("[channeldb] Unable to open the database file '%s': %s", cfg.database, unrealdb_get_error_string());
 				return 0;
 			}
 		} else
 		{
 			config_warn("[channeldb] Unable to open the database file '%s' for reading: %s", cfg.database, unrealdb_get_error_string());
 			return 0;
 		}
 	}
 
 	R_SAFE(unrealdb_read_int32(db, &version));
 	if (version > channeldb_version)
 	{
 		config_warn("[channeldb] Database '%s' has a wrong version: expected it to be <= %u but got %u instead", cfg.database, channeldb_version, version);
 		unrealdb_close(db);
 		return 0;
 	}
 
 	R_SAFE(unrealdb_read_int64(db, &count));
 
 	for (i=1; i <= count; i++)
 	{
 		// Variables
 		chname = NULL;
 		creationtime = 0;
 		topic = NULL;
 		topic_nick = NULL;
 		topic_time = 0;
 		modes1 = NULL;
 		modes2 = NULL;
 		mode_lock = NULL;
 		
 		Channel *channel;
 		R_SAFE(unrealdb_read_int32(db, &magic));
 		if (magic != MAGIC_CHANNEL_START)
 		{
 			config_error("[channeldb] Corrupt database (%s) - channel magic start is 0x%x. Further reading aborted.", cfg.database, magic);
 			break;
 		}
 		R_SAFE(unrealdb_read_str(db, &chname));
 		R_SAFE(unrealdb_read_int64(db, &creationtime));
 		R_SAFE(unrealdb_read_str(db, &topic));
 		R_SAFE(unrealdb_read_str(db, &topic_nick));
 		R_SAFE(unrealdb_read_int64(db, &topic_time));
 		R_SAFE(unrealdb_read_str(db, &modes1));
 		R_SAFE(unrealdb_read_str(db, &modes2));
 		R_SAFE(unrealdb_read_str(db, &mode_lock));
 		/* If we got this far, we can create/initialize the channel with the above */
 		channel = make_channel(chname);
 		if (IsInvalidChannelTS(creationtime))
 			channel->creationtime = TStime();
 		else
 			channel->creationtime = creationtime;
 		safe_strdup(channel->topic, topic);
 		safe_strdup(channel->topic_nick, topic_nick);
 		channel->topic_time = topic_time;
 		safe_strdup(channel->mode_lock, mode_lock);
 		set_channel_mode(channel, NULL, modes1, modes2);
 		R_SAFE(read_listmode(db, &channel->banlist));
 		R_SAFE(read_listmode(db, &channel->exlist));
 		R_SAFE(read_listmode(db, &channel->invexlist));
 		R_SAFE(unrealdb_read_int32(db, &magic));
 		FreeChannelEntry();
 		added++;
 		if (magic != MAGIC_CHANNEL_END)
 		{
 			config_error("[channeldb] Corrupt database (%s) - channel magic end is 0x%x. Further reading aborted.", cfg.database, magic);
 			break;
 		}
 	}
 
 	unrealdb_close(db);
 
 	if (added)
 		config_status("[channeldb] Added %d persistent channels (+P)", added);
 #ifdef BENCHMARK
 	gettimeofday(&tv_beta, NULL);
 	unreal_log(ULOG_DEBUG, "channeldb", "CHANNELDB_BENCHMARK", NULL,
 	           "[channeldb] Benchmark: LOAD DB: $time_msec microseconds",
 	           log_data_integer("time_msec", ((tv_beta.tv_sec - tv_alpha.tv_sec) * 1000000) + (tv_beta.tv_usec - tv_alpha.tv_usec)));
 #endif
 	return 1;
 }
 #undef FreeChannelEntry
 #undef R_SAFE

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