/*
 *	check.c
 *
 *	server checks and output routines
 *
 *	Copyright (c) 2010-2014, PostgreSQL Global Development Group
 *	contrib/pg_upgrade/check.c
 */

#include "postgres_fe.h"

#include "catalog/pg_authid.h"
#include "mb/pg_wchar.h"
#include "pg_upgrade.h"


static void set_locale_and_encoding(ClusterInfo *cluster);
static void check_new_cluster_is_empty(void);
static void check_locale_and_encoding(ControlData *oldctrl,
						  ControlData *newctrl);
static bool equivalent_locale(const char *loca, const char *locb);
static bool equivalent_encoding(const char *chara, const char *charb);
static void check_is_install_user(ClusterInfo *cluster);
static void check_for_prepared_transactions(ClusterInfo *cluster);
static void check_for_isn_and_int8_passing_mismatch(ClusterInfo *cluster);
static void check_for_reg_data_type_usage(ClusterInfo *cluster);
static void get_bin_version(ClusterInfo *cluster);
static char *get_canonical_locale_name(int category, const char *locale);


/*
 * fix_path_separator
 * For non-Windows, just return the argument.
 * For Windows convert any forward slash to a backslash
 * such as is suitable for arguments to builtin commands
 * like RMDIR and DEL.
 */
static char *
fix_path_separator(char *path)
{
#ifdef WIN32

	char	   *result;
	char	   *c;

	result = pg_strdup(path);

	for (c = result; *c != '\0'; c++)
		if (*c == '/')
			*c = '\\';

	return result;
#else

	return path;
#endif
}

void
output_check_banner(bool live_check)
{
	if (user_opts.check && live_check)
	{
		pg_log(PG_REPORT, "Performing Consistency Checks on Old Live Server\n");
		pg_log(PG_REPORT, "------------------------------------------------\n");
	}
	else
	{
		pg_log(PG_REPORT, "Performing Consistency Checks\n");
		pg_log(PG_REPORT, "-----------------------------\n");
	}
}


void
check_and_dump_old_cluster(bool live_check, char **sequence_script_file_name)
{
	/* -- OLD -- */

	if (!live_check)
		start_postmaster(&old_cluster, true);

	set_locale_and_encoding(&old_cluster);

	get_pg_database_relfilenode(&old_cluster);

	/* Extract a list of databases and tables from the old cluster */
	get_db_and_rel_infos(&old_cluster);

	init_tablespaces();

	get_loadable_libraries();


	/*
	 * Check for various failure cases
	 */
	check_is_install_user(&old_cluster);
	check_for_prepared_transactions(&old_cluster);
	check_for_reg_data_type_usage(&old_cluster);
	check_for_isn_and_int8_passing_mismatch(&old_cluster);

	/* old = PG 8.3 checks? */
	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 803)
	{
		old_8_3_check_for_name_data_type_usage(&old_cluster);
		old_8_3_check_for_tsquery_usage(&old_cluster);
		old_8_3_check_ltree_usage(&old_cluster);
		if (user_opts.check)
		{
			old_8_3_rebuild_tsvector_tables(&old_cluster, true);
			old_8_3_invalidate_hash_gin_indexes(&old_cluster, true);
			old_8_3_invalidate_bpchar_pattern_ops_indexes(&old_cluster, true);
		}
		else

			/*
			 * While we have the old server running, create the script to
			 * properly restore its sequence values but we report this at the
			 * end.
			 */
			*sequence_script_file_name =
				old_8_3_create_sequence_script(&old_cluster);
	}

	/* Pre-PG 9.4 had a different 'line' data type internal format */
	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 903)
		old_9_3_check_for_line_data_type_usage(&old_cluster);

	/* Pre-PG 9.0 had no large object permissions */
	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 804)
		new_9_0_populate_pg_largeobject_metadata(&old_cluster, true);

	/*
	 * While not a check option, we do this now because this is the only time
	 * the old server is running.
	 */
	if (!user_opts.check)
		generate_old_dump();

	if (!live_check)
		stop_postmaster(false);
}


void
check_new_cluster(void)
{
	set_locale_and_encoding(&new_cluster);

	check_locale_and_encoding(&old_cluster.controldata, &new_cluster.controldata);

	get_db_and_rel_infos(&new_cluster);

	check_new_cluster_is_empty();

	check_loadable_libraries();

	if (user_opts.transfer_mode == TRANSFER_MODE_LINK)
		check_hard_link();

	check_is_install_user(&new_cluster);

	check_for_prepared_transactions(&new_cluster);
}


void
report_clusters_compatible(void)
{
	if (user_opts.check)
	{
		pg_log(PG_REPORT, "\n*Clusters are compatible*\n");
		/* stops new cluster */
		stop_postmaster(false);
		exit(0);
	}

	pg_log(PG_REPORT, "\n"
		   "If pg_upgrade fails after this point, you must re-initdb the\n"
		   "new cluster before continuing.\n");
}


void
issue_warnings(char *sequence_script_file_name)
{
	/* old = PG 8.3 warnings? */
	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 803)
	{
		start_postmaster(&new_cluster, true);

		/* restore proper sequence values using file created from old server */
		if (sequence_script_file_name)
		{
			prep_status("Adjusting sequences");
			exec_prog(UTILITY_LOG_FILE, NULL, true,
					  "\"%s/psql\" " EXEC_PSQL_ARGS " %s -f \"%s\"",
					  new_cluster.bindir, cluster_conn_opts(&new_cluster),
					  sequence_script_file_name);
			unlink(sequence_script_file_name);
			check_ok();
		}

		old_8_3_rebuild_tsvector_tables(&new_cluster, false);
		old_8_3_invalidate_hash_gin_indexes(&new_cluster, false);
		old_8_3_invalidate_bpchar_pattern_ops_indexes(&new_cluster, false);
		stop_postmaster(false);
	}

	/* Create dummy large object permissions for old < PG 9.0? */
	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 804)
	{
		start_postmaster(&new_cluster, true);
		new_9_0_populate_pg_largeobject_metadata(&new_cluster, false);
		stop_postmaster(false);
	}
}


void
output_completion_banner(char *analyze_script_file_name,
						 char *deletion_script_file_name)
{
	/* Did we copy the free space files? */
	if (GET_MAJOR_VERSION(old_cluster.major_version) >= 804)
		pg_log(PG_REPORT,
			   "Optimizer statistics are not transferred by pg_upgrade so,\n"
			   "once you start the new server, consider running:\n"
			   "    %s\n\n", analyze_script_file_name);
	else
		pg_log(PG_REPORT,
			   "Optimizer statistics and free space information are not transferred\n"
		"by pg_upgrade so, once you start the new server, consider running:\n"
			   "    %s\n\n", analyze_script_file_name);


	if (deletion_script_file_name)
		pg_log(PG_REPORT,
			"Running this script will delete the old cluster's data files:\n"
			   "    %s\n",
			   deletion_script_file_name);
	else
		pg_log(PG_REPORT,
			   "Could not create a script to delete the old cluster's data\n"
		  "files because user-defined tablespaces exist in the old cluster\n"
		"directory.  The old cluster's contents must be deleted manually.\n");
}


void
check_cluster_versions(void)
{
	prep_status("Checking cluster versions");

	/* get old and new cluster versions */
	old_cluster.major_version = get_major_server_version(&old_cluster);
	new_cluster.major_version = get_major_server_version(&new_cluster);

	/*
	 * We allow upgrades from/to the same major version for alpha/beta
	 * upgrades
	 */

	if (GET_MAJOR_VERSION(old_cluster.major_version) < 803)
		pg_fatal("This utility can only upgrade from PostgreSQL version 8.3 and later.\n");

	/* Only current PG version is supported as a target */
	if (GET_MAJOR_VERSION(new_cluster.major_version) != GET_MAJOR_VERSION(PG_VERSION_NUM))
		pg_fatal("This utility can only upgrade to PostgreSQL version %s.\n",
				 PG_MAJORVERSION);

	/*
	 * We can't allow downgrading because we use the target pg_dump, and
	 * pg_dump cannot operate on newer database versions, only current and
	 * older versions.
	 */
	if (old_cluster.major_version > new_cluster.major_version)
		pg_fatal("This utility cannot be used to downgrade to older major PostgreSQL versions.\n");

	/* get old and new binary versions */
	get_bin_version(&old_cluster);
	get_bin_version(&new_cluster);

	/* Ensure binaries match the designated data directories */
	if (GET_MAJOR_VERSION(old_cluster.major_version) !=
		GET_MAJOR_VERSION(old_cluster.bin_version))
		pg_fatal("Old cluster data and binary directories are from different major versions.\n");
	if (GET_MAJOR_VERSION(new_cluster.major_version) !=
		GET_MAJOR_VERSION(new_cluster.bin_version))
		pg_fatal("New cluster data and binary directories are from different major versions.\n");

	check_ok();
}


void
check_cluster_compatibility(bool live_check)
{
	/* get/check pg_control data of servers */
	get_control_data(&old_cluster, live_check);
	get_control_data(&new_cluster, false);
	check_control_data(&old_cluster.controldata, &new_cluster.controldata);

	/* Is it 9.0 but without tablespace directories? */
	if (GET_MAJOR_VERSION(new_cluster.major_version) == 900 &&
		new_cluster.controldata.cat_ver < TABLE_SPACE_SUBDIRS_CAT_VER)
		pg_fatal("This utility can only upgrade to PostgreSQL version 9.0 after 2010-01-11\n"
				 "because of backend API changes made during development.\n");

	/* We read the real port number for PG >= 9.1 */
	if (live_check && GET_MAJOR_VERSION(old_cluster.major_version) < 901 &&
		old_cluster.port == DEF_PGUPORT)
		pg_fatal("When checking a pre-PG 9.1 live old server, "
				 "you must specify the old server's port number.\n");

	if (live_check && old_cluster.port == new_cluster.port)
		pg_fatal("When checking a live server, "
				 "the old and new port numbers must be different.\n");
}


/*
 * set_locale_and_encoding()
 *
 * query the database to get the template0 locale
 */
static void
set_locale_and_encoding(ClusterInfo *cluster)
{
	ControlData *ctrl = &cluster->controldata;
	PGconn	   *conn;
	PGresult   *res;
	int			i_encoding;
	int			cluster_version = cluster->major_version;

	conn = connectToServer(cluster, "template1");

	/* for pg < 80400, we got the values from pg_controldata */
	if (cluster_version >= 80400)
	{
		int			i_datcollate;
		int			i_datctype;

		res = executeQueryOrDie(conn,
								"SELECT datcollate, datctype "
								"FROM	pg_catalog.pg_database "
								"WHERE	datname = 'template0' ");
		assert(PQntuples(res) == 1);

		i_datcollate = PQfnumber(res, "datcollate");
		i_datctype = PQfnumber(res, "datctype");

		if (GET_MAJOR_VERSION(cluster->major_version) < 902)
		{
			/*
			 * Pre-9.2 did not canonicalize the supplied locale names to match
			 * what the system returns, while 9.2+ does, so convert pre-9.2 to
			 * match.
			 */
			ctrl->lc_collate = get_canonical_locale_name(LC_COLLATE,
								pg_strdup(PQgetvalue(res, 0, i_datcollate)));
			ctrl->lc_ctype = get_canonical_locale_name(LC_CTYPE,
								  pg_strdup(PQgetvalue(res, 0, i_datctype)));
		}
		else
		{
			ctrl->lc_collate = pg_strdup(PQgetvalue(res, 0, i_datcollate));
			ctrl->lc_ctype = pg_strdup(PQgetvalue(res, 0, i_datctype));
		}

		PQclear(res);
	}

	res = executeQueryOrDie(conn,
							"SELECT pg_catalog.pg_encoding_to_char(encoding) "
							"FROM	pg_catalog.pg_database "
							"WHERE	datname = 'template0' ");
	assert(PQntuples(res) == 1);

	i_encoding = PQfnumber(res, "pg_encoding_to_char");
	ctrl->encoding = pg_strdup(PQgetvalue(res, 0, i_encoding));

	PQclear(res);

	PQfinish(conn);
}


/*
 * check_locale_and_encoding()
 *
 * Check that old and new locale and encoding match.  Even though the backend
 * tries to canonicalize stored locale names, the platform often doesn't
 * cooperate, so it's entirely possible that one DB thinks its locale is
 * "en_US.UTF-8" while the other says "en_US.utf8".  Try to be forgiving.
 */
static void
check_locale_and_encoding(ControlData *oldctrl,
						  ControlData *newctrl)
{
	if (!equivalent_locale(oldctrl->lc_collate, newctrl->lc_collate))
		pg_fatal("lc_collate cluster values do not match:  old \"%s\", new \"%s\"\n",
				 oldctrl->lc_collate, newctrl->lc_collate);
	if (!equivalent_locale(oldctrl->lc_ctype, newctrl->lc_ctype))
		pg_fatal("lc_ctype cluster values do not match:  old \"%s\", new \"%s\"\n",
				 oldctrl->lc_ctype, newctrl->lc_ctype);
	if (!equivalent_encoding(oldctrl->encoding, newctrl->encoding))
		pg_fatal("encoding cluster values do not match:  old \"%s\", new \"%s\"\n",
				 oldctrl->encoding, newctrl->encoding);
}

/*
 * equivalent_locale()
 *
 * Best effort locale-name comparison.  Return false if we are not 100% sure
 * the locales are equivalent.
 */
static bool
equivalent_locale(const char *loca, const char *locb)
{
	const char *chara = strrchr(loca, '.');
	const char *charb = strrchr(locb, '.');
	int			lencmp;

	/* If they don't both contain an encoding part, just do strcasecmp(). */
	if (!chara || !charb)
		return (pg_strcasecmp(loca, locb) == 0);

	/*
	 * Compare the encoding parts.  Windows tends to use code page numbers for
	 * the encoding part, which equivalent_encoding() won't like, so accept if
	 * the strings are case-insensitive equal; otherwise use
	 * equivalent_encoding() to compare.
	 */
	if (pg_strcasecmp(chara + 1, charb + 1) != 0 &&
		!equivalent_encoding(chara + 1, charb + 1))
		return false;

	/*
	 * OK, compare the locale identifiers (e.g. en_US part of en_US.utf8).
	 *
	 * It's tempting to ignore non-alphanumeric chars here, but for now it's
	 * not clear that that's necessary; just do case-insensitive comparison.
	 */
	lencmp = chara - loca;
	if (lencmp != charb - locb)
		return false;

	return (pg_strncasecmp(loca, locb, lencmp) == 0);
}

/*
 * equivalent_encoding()
 *
 * Best effort encoding-name comparison.  Return true only if the encodings
 * are valid server-side encodings and known equivalent.
 *
 * Because the lookup in pg_valid_server_encoding() does case folding and
 * ignores non-alphanumeric characters, this will recognize many popular
 * variant spellings as equivalent, eg "utf8" and "UTF-8" will match.
 */
static bool
equivalent_encoding(const char *chara, const char *charb)
{
	int			enca = pg_valid_server_encoding(chara);
	int			encb = pg_valid_server_encoding(charb);

	if (enca < 0 || encb < 0)
		return false;

	return (enca == encb);
}


static void
check_new_cluster_is_empty(void)
{
	int			dbnum;

	for (dbnum = 0; dbnum < new_cluster.dbarr.ndbs; dbnum++)
	{
		int			relnum;
		RelInfoArr *rel_arr = &new_cluster.dbarr.dbs[dbnum].rel_arr;

		for (relnum = 0; relnum < rel_arr->nrels;
			 relnum++)
		{
			/* pg_largeobject and its index should be skipped */
			if (strcmp(rel_arr->rels[relnum].nspname, "pg_catalog") != 0)
				pg_fatal("New cluster database \"%s\" is not empty\n",
						 new_cluster.dbarr.dbs[dbnum].db_name);
		}
	}

}


/*
 * create_script_for_cluster_analyze()
 *
 *	This incrementally generates better optimizer statistics
 */
void
create_script_for_cluster_analyze(char **analyze_script_file_name)
{
	FILE	   *script = NULL;
	char	   *user_specification = "";

	prep_status("Creating script to analyze new cluster");

	if (os_info.user_specified)
		user_specification = psprintf("-U \"%s\" ", os_info.user);

	*analyze_script_file_name = psprintf("analyze_new_cluster.%s", SCRIPT_EXT);

	if ((script = fopen_priv(*analyze_script_file_name, "w")) == NULL)
		pg_fatal("Could not open file \"%s\": %s\n",
				 *analyze_script_file_name, getErrorText(errno));

#ifndef WIN32
	/* add shebang header */
	fprintf(script, "#!/bin/sh\n\n");
#else
	/* suppress command echoing */
	fprintf(script, "@echo off\n");
#endif

	fprintf(script, "echo %sThis script will generate minimal optimizer statistics rapidly%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %sso your system is usable, and then gather statistics twice more%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %swith increasing accuracy.  When it is done, your system will%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %shave the default level of optimizer statistics.%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo%s\n\n", ECHO_BLANK);

	fprintf(script, "echo %sIf you have used ALTER TABLE to modify the statistics target for%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %sany tables, you might want to remove them and restore them after%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %srunning this script because they will delay fast statistics generation.%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo%s\n\n", ECHO_BLANK);

	fprintf(script, "echo %sIf you would like default statistics as quickly as possible, cancel%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %sthis script and run:%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %s    \"%s/vacuumdb\" %s--all %s%s\n", ECHO_QUOTE,
			new_cluster.bindir, user_specification,
	/* Did we copy the free space files? */
			(GET_MAJOR_VERSION(old_cluster.major_version) >= 804) ?
			"--analyze-only" : "--analyze", ECHO_QUOTE);
	fprintf(script, "echo%s\n\n", ECHO_BLANK);

	fprintf(script, "\"%s/vacuumdb\" %s--all --analyze-in-stages\n",
			new_cluster.bindir, user_specification);
	/* Did we copy the free space files? */
	if (GET_MAJOR_VERSION(old_cluster.major_version) < 804)
		fprintf(script, "\"%s/vacuumdb\" %s--all\n", new_cluster.bindir,
				user_specification);

	fprintf(script, "echo%s\n\n", ECHO_BLANK);
	fprintf(script, "echo %sDone%s\n",
			ECHO_QUOTE, ECHO_QUOTE);

	fclose(script);

#ifndef WIN32
	if (chmod(*analyze_script_file_name, S_IRWXU) != 0)
		pg_fatal("Could not add execute permission to file \"%s\": %s\n",
				 *analyze_script_file_name, getErrorText(errno));
#endif

	if (os_info.user_specified)
		pg_free(user_specification);

	check_ok();
}


/*
 * create_script_for_old_cluster_deletion()
 *
 *	This is particularly useful for tablespace deletion.
 */
void
create_script_for_old_cluster_deletion(char **deletion_script_file_name)
{
	FILE	   *script = NULL;
	int			tblnum;
	char		old_cluster_pgdata[MAXPGPATH];

	*deletion_script_file_name = psprintf("delete_old_cluster.%s", SCRIPT_EXT);

	/*
	 * Some users (oddly) create tablespaces inside the cluster data
	 * directory.  We can't create a proper old cluster delete script in that
	 * case.
	 */
	strlcpy(old_cluster_pgdata, old_cluster.pgdata, MAXPGPATH);
	canonicalize_path(old_cluster_pgdata);
	for (tblnum = 0; tblnum < os_info.num_old_tablespaces; tblnum++)
	{
		char		old_tablespace_dir[MAXPGPATH];

		strlcpy(old_tablespace_dir, os_info.old_tablespaces[tblnum], MAXPGPATH);
		canonicalize_path(old_tablespace_dir);
		if (path_is_prefix_of_path(old_cluster_pgdata, old_tablespace_dir))
		{
			/* Unlink file in case it is left over from a previous run. */
			unlink(*deletion_script_file_name);
			pg_free(*deletion_script_file_name);
			*deletion_script_file_name = NULL;
			return;
		}
	}

	prep_status("Creating script to delete old cluster");

	if ((script = fopen_priv(*deletion_script_file_name, "w")) == NULL)
		pg_fatal("Could not open file \"%s\": %s\n",
				 *deletion_script_file_name, getErrorText(errno));

#ifndef WIN32
	/* add shebang header */
	fprintf(script, "#!/bin/sh\n\n");
#endif

	/* delete old cluster's default tablespace */
	fprintf(script, RMDIR_CMD " %s\n", fix_path_separator(old_cluster.pgdata));

	/* delete old cluster's alternate tablespaces */
	for (tblnum = 0; tblnum < os_info.num_old_tablespaces; tblnum++)
	{
		/*
		 * Do the old cluster's per-database directories share a directory
		 * with a new version-specific tablespace?
		 */
		if (strlen(old_cluster.tablespace_suffix) == 0)
		{
			/* delete per-database directories */
			int			dbnum;

			fprintf(script, "\n");
			/* remove PG_VERSION? */
			if (GET_MAJOR_VERSION(old_cluster.major_version) <= 804)
				fprintf(script, RM_CMD " %s%cPG_VERSION\n",
						fix_path_separator(os_info.old_tablespaces[tblnum]),
						PATH_SEPARATOR);

			for (dbnum = 0; dbnum < old_cluster.dbarr.ndbs; dbnum++)
				fprintf(script, RMDIR_CMD " %s%c%d\n",
						fix_path_separator(os_info.old_tablespaces[tblnum]),
						PATH_SEPARATOR, old_cluster.dbarr.dbs[dbnum].db_oid);
		}
		else
		{
			char	   *suffix_path = pg_strdup(old_cluster.tablespace_suffix);

			/*
			 * Simply delete the tablespace directory, which might be ".old"
			 * or a version-specific subdirectory.
			 */
			fprintf(script, RMDIR_CMD " %s%s\n",
					fix_path_separator(os_info.old_tablespaces[tblnum]),
					fix_path_separator(suffix_path));
			pfree(suffix_path);
		}
	}

	fclose(script);

#ifndef WIN32
	if (chmod(*deletion_script_file_name, S_IRWXU) != 0)
		pg_fatal("Could not add execute permission to file \"%s\": %s\n",
				 *deletion_script_file_name, getErrorText(errno));
#endif

	check_ok();
}


/*
 *	check_is_install_user()
 *
 *	Check we are the install user, and that the new cluster
 *	has no other users.
 */
static void
check_is_install_user(ClusterInfo *cluster)
{
	PGresult   *res;
	PGconn	   *conn = connectToServer(cluster, "template1");

	prep_status("Checking database user is the install user");

	/* Can't use pg_authid because only superusers can view it. */
	res = executeQueryOrDie(conn,
							"SELECT rolsuper, oid "
							"FROM pg_catalog.pg_roles "
							"WHERE rolname = current_user");

	/*
	 * We only allow the install user in the new cluster (see comment below)
	 * and we preserve pg_authid.oid, so this must be the install user in
	 * the old cluster too.
	 */
	if (PQntuples(res) != 1 ||
		atooid(PQgetvalue(res, 0, 1)) != BOOTSTRAP_SUPERUSERID)
		pg_fatal("database user \"%s\" is not the install user\n",
				 os_info.user);

	PQclear(res);

	res = executeQueryOrDie(conn,
							"SELECT COUNT(*) "
							"FROM pg_catalog.pg_roles ");

	if (PQntuples(res) != 1)
		pg_fatal("could not determine the number of users\n");

	/*
	 * We only allow the install user in the new cluster because other defined
	 * users might match users defined in the old cluster and generate an
	 * error during pg_dump restore.
	 */
	if (cluster == &new_cluster && atooid(PQgetvalue(res, 0, 0)) != 1)
		pg_fatal("Only the install user can be defined in the new cluster.\n");

	PQclear(res);

	PQfinish(conn);

	check_ok();
}


/*
 *	check_for_prepared_transactions()
 *
 *	Make sure there are no prepared transactions because the storage format
 *	might have changed.
 */
static void
check_for_prepared_transactions(ClusterInfo *cluster)
{
	PGresult   *res;
	PGconn	   *conn = connectToServer(cluster, "template1");

	prep_status("Checking for prepared transactions");

	res = executeQueryOrDie(conn,
							"SELECT * "
							"FROM pg_catalog.pg_prepared_xacts");

	if (PQntuples(res) != 0)
		pg_fatal("The %s cluster contains prepared transactions\n",
				 CLUSTER_NAME(cluster));

	PQclear(res);

	PQfinish(conn);

	check_ok();
}


/*
 *	check_for_isn_and_int8_passing_mismatch()
 *
 *	contrib/isn relies on data type int8, and in 8.4 int8 can now be passed
 *	by value.  The schema dumps the CREATE TYPE PASSEDBYVALUE setting so
 *	it must match for the old and new servers.
 */
static void
check_for_isn_and_int8_passing_mismatch(ClusterInfo *cluster)
{
	int			dbnum;
	FILE	   *script = NULL;
	bool		found = false;
	char		output_path[MAXPGPATH];

	prep_status("Checking for contrib/isn with bigint-passing mismatch");

	if (old_cluster.controldata.float8_pass_by_value ==
		new_cluster.controldata.float8_pass_by_value)
	{
		/* no mismatch */
		check_ok();
		return;
	}

	snprintf(output_path, sizeof(output_path),
			 "contrib_isn_and_int8_pass_by_value.txt");

	for (dbnum = 0; dbnum < cluster->dbarr.ndbs; dbnum++)
	{
		PGresult   *res;
		bool		db_used = false;
		int			ntups;
		int			rowno;
		int			i_nspname,
					i_proname;
		DbInfo	   *active_db = &cluster->dbarr.dbs[dbnum];
		PGconn	   *conn = connectToServer(cluster, active_db->db_name);

		/* Find any functions coming from contrib/isn */
		res = executeQueryOrDie(conn,
								"SELECT n.nspname, p.proname "
								"FROM	pg_catalog.pg_proc p, "
								"		pg_catalog.pg_namespace n "
								"WHERE	p.pronamespace = n.oid AND "
								"		p.probin = '$libdir/isn'");

		ntups = PQntuples(res);
		i_nspname = PQfnumber(res, "nspname");
		i_proname = PQfnumber(res, "proname");
		for (rowno = 0; rowno < ntups; rowno++)
		{
			found = true;
			if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
				pg_fatal("Could not open file \"%s\": %s\n",
						 output_path, getErrorText(errno));
			if (!db_used)
			{
				fprintf(script, "Database: %s\n", active_db->db_name);
				db_used = true;
			}
			fprintf(script, "  %s.%s\n",
					PQgetvalue(res, rowno, i_nspname),
					PQgetvalue(res, rowno, i_proname));
		}

		PQclear(res);

		PQfinish(conn);
	}

	if (script)
		fclose(script);

	if (found)
	{
		pg_log(PG_REPORT, "fatal\n");
		pg_fatal("Your installation contains \"contrib/isn\" functions which rely on the\n"
		  "bigint data type.  Your old and new clusters pass bigint values\n"
		"differently so this cluster cannot currently be upgraded.  You can\n"
				 "manually upgrade databases that use \"contrib/isn\" facilities and remove\n"
				 "\"contrib/isn\" from the old cluster and restart the upgrade.  A list of\n"
				 "the problem functions is in the file:\n"
				 "    %s\n\n", output_path);
	}
	else
		check_ok();
}


/*
 * check_for_reg_data_type_usage()
 *	pg_upgrade only preserves these system values:
 *		pg_class.oid
 *		pg_type.oid
 *		pg_enum.oid
 *
 *	Many of the reg* data types reference system catalog info that is
 *	not preserved, and hence these data types cannot be used in user
 *	tables upgraded by pg_upgrade.
 */
static void
check_for_reg_data_type_usage(ClusterInfo *cluster)
{
	int			dbnum;
	FILE	   *script = NULL;
	bool		found = false;
	char		output_path[MAXPGPATH];

	prep_status("Checking for reg* system OID user data types");

	snprintf(output_path, sizeof(output_path), "tables_using_reg.txt");

	for (dbnum = 0; dbnum < cluster->dbarr.ndbs; dbnum++)
	{
		PGresult   *res;
		bool		db_used = false;
		int			ntups;
		int			rowno;
		int			i_nspname,
					i_relname,
					i_attname;
		DbInfo	   *active_db = &cluster->dbarr.dbs[dbnum];
		PGconn	   *conn = connectToServer(cluster, active_db->db_name);

		/*
		 * While several relkinds don't store any data, e.g. views, they can
		 * be used to define data types of other columns, so we check all
		 * relkinds.
		 */
		res = executeQueryOrDie(conn,
								"SELECT n.nspname, c.relname, a.attname "
								"FROM	pg_catalog.pg_class c, "
								"		pg_catalog.pg_namespace n, "
								"		pg_catalog.pg_attribute a "
								"WHERE	c.oid = a.attrelid AND "
								"		NOT a.attisdropped AND "
								"		a.atttypid IN ( "
		  "			'pg_catalog.regproc'::pg_catalog.regtype, "
								"			'pg_catalog.regprocedure'::pg_catalog.regtype, "
		  "			'pg_catalog.regoper'::pg_catalog.regtype, "
								"			'pg_catalog.regoperator'::pg_catalog.regtype, "
		/* regclass.oid is preserved, so 'regclass' is OK */
		/* regtype.oid is preserved, so 'regtype' is OK */
		"			'pg_catalog.regconfig'::pg_catalog.regtype, "
								"			'pg_catalog.regdictionary'::pg_catalog.regtype) AND "
								"		c.relnamespace = n.oid AND "
							  "		n.nspname NOT IN ('pg_catalog', 'information_schema')");

		ntups = PQntuples(res);
		i_nspname = PQfnumber(res, "nspname");
		i_relname = PQfnumber(res, "relname");
		i_attname = PQfnumber(res, "attname");
		for (rowno = 0; rowno < ntups; rowno++)
		{
			found = true;
			if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
				pg_fatal("Could not open file \"%s\": %s\n",
						 output_path, getErrorText(errno));
			if (!db_used)
			{
				fprintf(script, "Database: %s\n", active_db->db_name);
				db_used = true;
			}
			fprintf(script, "  %s.%s.%s\n",
					PQgetvalue(res, rowno, i_nspname),
					PQgetvalue(res, rowno, i_relname),
					PQgetvalue(res, rowno, i_attname));
		}

		PQclear(res);

		PQfinish(conn);
	}

	if (script)
		fclose(script);

	if (found)
	{
		pg_log(PG_REPORT, "fatal\n");
		pg_fatal("Your installation contains one of the reg* data types in user tables.\n"
		 "These data types reference system OIDs that are not preserved by\n"
		"pg_upgrade, so this cluster cannot currently be upgraded.  You can\n"
				 "remove the problem tables and restart the upgrade.  A list of the problem\n"
				 "columns is in the file:\n"
				 "    %s\n\n", output_path);
	}
	else
		check_ok();
}


static void
get_bin_version(ClusterInfo *cluster)
{
	char		cmd[MAXPGPATH],
				cmd_output[MAX_STRING];
	FILE	   *output;
	int			pre_dot,
				post_dot;

	snprintf(cmd, sizeof(cmd), "\"%s/pg_ctl\" --version", cluster->bindir);

	if ((output = popen(cmd, "r")) == NULL ||
		fgets(cmd_output, sizeof(cmd_output), output) == NULL)
		pg_fatal("Could not get pg_ctl version data using %s: %s\n",
				 cmd, getErrorText(errno));

	pclose(output);

	/* Remove trailing newline */
	if (strchr(cmd_output, '\n') != NULL)
		*strchr(cmd_output, '\n') = '\0';

	if (sscanf(cmd_output, "%*s %*s %d.%d", &pre_dot, &post_dot) != 2)
		pg_fatal("could not get version from %s\n", cmd);

	cluster->bin_version = (pre_dot * 100 + post_dot) * 100;
}


/*
 * get_canonical_locale_name
 *
 * Send the locale name to the system, and hope we get back a canonical
 * version.  This should match the backend's check_locale() function.
 */
static char *
get_canonical_locale_name(int category, const char *locale)
{
	char	   *save;
	char	   *res;

	/* get the current setting, so we can restore it. */
	save = setlocale(category, NULL);
	if (!save)
		pg_fatal("failed to get the current locale\n");

	/* 'save' may be pointing at a modifiable scratch variable, so copy it. */
	save = pg_strdup(save);

	/* set the locale with setlocale, to see if it accepts it. */
	res = setlocale(category, locale);

	if (!res)
		pg_fatal("failed to get system locale name for \"%s\"\n", locale);

	res = pg_strdup(res);

	/* restore old value. */
	if (!setlocale(category, save))
		pg_fatal("failed to restore old locale \"%s\"\n", save);

	pg_free(save);

	return res;
}
