Adding upstream version 15.5.upstream/15.5

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 864 insertions, 0 deletions

diff --git a/src/bin/pg_basebackup/streamutil.c b/src/bin/pg_basebackup/streamutil.c
new file mode 100644
index 0000000..1478aa9
--- /dev/null
+++ b/src/bin/pg_basebackup/streamutil.c
@@ -0,0 +1,864 @@
+/*-------------------------------------------------------------------------
+ *
+ * streamutil.c - utility functions for pg_basebackup, pg_receivewal and
+ *					pg_recvlogical
+ *
+ * Author: Magnus Hagander <magnus@hagander.net>
+ *
+ * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		  src/bin/pg_basebackup/streamutil.c
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres_fe.h"
+
+#include <sys/time.h>
+#include <unistd.h>
+
+#include "access/xlog_internal.h"
+#include "common/connect.h"
+#include "common/fe_memutils.h"
+#include "common/file_perm.h"
+#include "common/logging.h"
+#include "common/string.h"
+#include "datatype/timestamp.h"
+#include "port/pg_bswap.h"
+#include "pqexpbuffer.h"
+#include "receivelog.h"
+#include "streamutil.h"
+
+#define ERRCODE_DUPLICATE_OBJECT  "42710"
+
+uint32		WalSegSz;
+
+static bool RetrieveDataDirCreatePerm(PGconn *conn);
+
+/* SHOW command for replication connection was introduced in version 10 */
+#define MINIMUM_VERSION_FOR_SHOW_CMD 100000
+
+/*
+ * Group access is supported from version 11.
+ */
+#define MINIMUM_VERSION_FOR_GROUP_ACCESS 110000
+
+const char *progname;
+char	   *connection_string = NULL;
+char	   *dbhost = NULL;
+char	   *dbuser = NULL;
+char	   *dbport = NULL;
+char	   *dbname = NULL;
+int			dbgetpassword = 0;	/* 0=auto, -1=never, 1=always */
+static char *password = NULL;
+PGconn	   *conn = NULL;
+
+/*
+ * Connect to the server. Returns a valid PGconn pointer if connected,
+ * or NULL on non-permanent error. On permanent error, the function will
+ * call exit(1) directly.
+ */
+PGconn *
+GetConnection(void)
+{
+	PGconn	   *tmpconn;
+	int			argcount = 7;	/* dbname, replication, fallback_app_name,
+								 * host, user, port, password */
+	int			i;
+	const char **keywords;
+	const char **values;
+	const char *tmpparam;
+	bool		need_password;
+	PQconninfoOption *conn_opts = NULL;
+	PQconninfoOption *conn_opt;
+	char	   *err_msg = NULL;
+
+	/* pg_recvlogical uses dbname only; others use connection_string only. */
+	Assert(dbname == NULL || connection_string == NULL);
+
+	/*
+	 * Merge the connection info inputs given in form of connection string,
+	 * options and default values (dbname=replication, replication=true, etc.)
+	 * Explicitly discard any dbname value in the connection string;
+	 * otherwise, PQconnectdbParams() would interpret that value as being
+	 * itself a connection string.
+	 */
+	i = 0;
+	if (connection_string)
+	{
+		conn_opts = PQconninfoParse(connection_string, &err_msg);
+		if (conn_opts == NULL)
+			pg_fatal("%s", err_msg);
+
+		for (conn_opt = conn_opts; conn_opt->keyword != NULL; conn_opt++)
+		{
+			if (conn_opt->val != NULL && conn_opt->val[0] != '\0' &&
+				strcmp(conn_opt->keyword, "dbname") != 0)
+				argcount++;
+		}
+
+		keywords = pg_malloc0((argcount + 1) * sizeof(*keywords));
+		values = pg_malloc0((argcount + 1) * sizeof(*values));
+
+		for (conn_opt = conn_opts; conn_opt->keyword != NULL; conn_opt++)
+		{
+			if (conn_opt->val != NULL && conn_opt->val[0] != '\0' &&
+				strcmp(conn_opt->keyword, "dbname") != 0)
+			{
+				keywords[i] = conn_opt->keyword;
+				values[i] = conn_opt->val;
+				i++;
+			}
+		}
+	}
+	else
+	{
+		keywords = pg_malloc0((argcount + 1) * sizeof(*keywords));
+		values = pg_malloc0((argcount + 1) * sizeof(*values));
+	}
+
+	keywords[i] = "dbname";
+	values[i] = dbname == NULL ? "replication" : dbname;
+	i++;
+	keywords[i] = "replication";
+	values[i] = dbname == NULL ? "true" : "database";
+	i++;
+	keywords[i] = "fallback_application_name";
+	values[i] = progname;
+	i++;
+
+	if (dbhost)
+	{
+		keywords[i] = "host";
+		values[i] = dbhost;
+		i++;
+	}
+	if (dbuser)
+	{
+		keywords[i] = "user";
+		values[i] = dbuser;
+		i++;
+	}
+	if (dbport)
+	{
+		keywords[i] = "port";
+		values[i] = dbport;
+		i++;
+	}
+
+	/* If -W was given, force prompt for password, but only the first time */
+	need_password = (dbgetpassword == 1 && !password);
+
+	do
+	{
+		/* Get a new password if appropriate */
+		if (need_password)
+		{
+			if (password)
+				free(password);
+			password = simple_prompt("Password: ", false);
+			need_password = false;
+		}
+
+		/* Use (or reuse, on a subsequent connection) password if we have it */
+		if (password)
+		{
+			keywords[i] = "password";
+			values[i] = password;
+		}
+		else
+		{
+			keywords[i] = NULL;
+			values[i] = NULL;
+		}
+
+		tmpconn = PQconnectdbParams(keywords, values, true);
+
+		/*
+		 * If there is too little memory even to allocate the PGconn object
+		 * and PQconnectdbParams returns NULL, we call exit(1) directly.
+		 */
+		if (!tmpconn)
+			pg_fatal("could not connect to server");
+
+		/* If we need a password and -w wasn't given, loop back and get one */
+		if (PQstatus(tmpconn) == CONNECTION_BAD &&
+			PQconnectionNeedsPassword(tmpconn) &&
+			dbgetpassword != -1)
+		{
+			PQfinish(tmpconn);
+			need_password = true;
+		}
+	}
+	while (need_password);
+
+	if (PQstatus(tmpconn) != CONNECTION_OK)
+	{
+		pg_log_error("%s", PQerrorMessage(tmpconn));
+		PQfinish(tmpconn);
+		free(values);
+		free(keywords);
+		if (conn_opts)
+			PQconninfoFree(conn_opts);
+		return NULL;
+	}
+
+	/* Connection ok! */
+	free(values);
+	free(keywords);
+	if (conn_opts)
+		PQconninfoFree(conn_opts);
+
+	/*
+	 * Set always-secure search path, so malicious users can't get control.
+	 * The capacity to run normal SQL queries was added in PostgreSQL 10, so
+	 * the search path cannot be changed (by us or attackers) on earlier
+	 * versions.
+	 */
+	if (dbname != NULL && PQserverVersion(tmpconn) >= 100000)
+	{
+		PGresult   *res;
+
+		res = PQexec(tmpconn, ALWAYS_SECURE_SEARCH_PATH_SQL);
+		if (PQresultStatus(res) != PGRES_TUPLES_OK)
+		{
+			pg_log_error("could not clear search_path: %s",
+						 PQerrorMessage(tmpconn));
+			PQclear(res);
+			PQfinish(tmpconn);
+			exit(1);
+		}
+		PQclear(res);
+	}
+
+	/*
+	 * Ensure we have the same value of integer_datetimes (now always "on") as
+	 * the server we are connecting to.
+	 */
+	tmpparam = PQparameterStatus(tmpconn, "integer_datetimes");
+	if (!tmpparam)
+	{
+		pg_log_error("could not determine server setting for integer_datetimes");
+		PQfinish(tmpconn);
+		exit(1);
+	}
+
+	if (strcmp(tmpparam, "on") != 0)
+	{
+		pg_log_error("integer_datetimes compile flag does not match server");
+		PQfinish(tmpconn);
+		exit(1);
+	}
+
+	/*
+	 * Retrieve the source data directory mode and use it to construct a umask
+	 * for creating directories and files.
+	 */
+	if (!RetrieveDataDirCreatePerm(tmpconn))
+	{
+		PQfinish(tmpconn);
+		exit(1);
+	}
+
+	return tmpconn;
+}
+
+/*
+ * From version 10, explicitly set wal segment size using SHOW wal_segment_size
+ * since ControlFile is not accessible here.
+ */
+bool
+RetrieveWalSegSize(PGconn *conn)
+{
+	PGresult   *res;
+	char		xlog_unit[3];
+	int			xlog_val,
+				multiplier = 1;
+
+	/* check connection existence */
+	Assert(conn != NULL);
+
+	/* for previous versions set the default xlog seg size */
+	if (PQserverVersion(conn) < MINIMUM_VERSION_FOR_SHOW_CMD)
+	{
+		WalSegSz = DEFAULT_XLOG_SEG_SIZE;
+		return true;
+	}
+
+	res = PQexec(conn, "SHOW wal_segment_size");
+	if (PQresultStatus(res) != PGRES_TUPLES_OK)
+	{
+		pg_log_error("could not send replication command \"%s\": %s",
+					 "SHOW wal_segment_size", PQerrorMessage(conn));
+
+		PQclear(res);
+		return false;
+	}
+	if (PQntuples(res) != 1 || PQnfields(res) < 1)
+	{
+		pg_log_error("could not fetch WAL segment size: got %d rows and %d fields, expected %d rows and %d or more fields",
+					 PQntuples(res), PQnfields(res), 1, 1);
+
+		PQclear(res);
+		return false;
+	}
+
+	/* fetch xlog value and unit from the result */
+	if (sscanf(PQgetvalue(res, 0, 0), "%d%2s", &xlog_val, xlog_unit) != 2)
+	{
+		pg_log_error("WAL segment size could not be parsed");
+		PQclear(res);
+		return false;
+	}
+
+	PQclear(res);
+
+	/* set the multiplier based on unit to convert xlog_val to bytes */
+	if (strcmp(xlog_unit, "MB") == 0)
+		multiplier = 1024 * 1024;
+	else if (strcmp(xlog_unit, "GB") == 0)
+		multiplier = 1024 * 1024 * 1024;
+
+	/* convert and set WalSegSz */
+	WalSegSz = xlog_val * multiplier;
+
+	if (!IsValidWalSegSize(WalSegSz))
+	{
+		pg_log_error(ngettext("WAL segment size must be a power of two between 1 MB and 1 GB, but the remote server reported a value of %d byte",
+							  "WAL segment size must be a power of two between 1 MB and 1 GB, but the remote server reported a value of %d bytes",
+							  WalSegSz),
+					 WalSegSz);
+		return false;
+	}
+
+	return true;
+}
+
+/*
+ * RetrieveDataDirCreatePerm
+ *
+ * This function is used to determine the privileges on the server's PG data
+ * directory and, based on that, set what the permissions will be for
+ * directories and files we create.
+ *
+ * PG11 added support for (optionally) group read/execute rights to be set on
+ * the data directory.  Prior to PG11, only the owner was allowed to have rights
+ * on the data directory.
+ */
+static bool
+RetrieveDataDirCreatePerm(PGconn *conn)
+{
+	PGresult   *res;
+	int			data_directory_mode;
+
+	/* check connection existence */
+	Assert(conn != NULL);
+
+	/* for previous versions leave the default group access */
+	if (PQserverVersion(conn) < MINIMUM_VERSION_FOR_GROUP_ACCESS)
+		return true;
+
+	res = PQexec(conn, "SHOW data_directory_mode");
+	if (PQresultStatus(res) != PGRES_TUPLES_OK)
+	{
+		pg_log_error("could not send replication command \"%s\": %s",
+					 "SHOW data_directory_mode", PQerrorMessage(conn));
+
+		PQclear(res);
+		return false;
+	}
+	if (PQntuples(res) != 1 || PQnfields(res) < 1)
+	{
+		pg_log_error("could not fetch group access flag: got %d rows and %d fields, expected %d rows and %d or more fields",
+					 PQntuples(res), PQnfields(res), 1, 1);
+
+		PQclear(res);
+		return false;
+	}
+
+	if (sscanf(PQgetvalue(res, 0, 0), "%o", &data_directory_mode) != 1)
+	{
+		pg_log_error("group access flag could not be parsed: %s",
+					 PQgetvalue(res, 0, 0));
+
+		PQclear(res);
+		return false;
+	}
+
+	SetDataDirectoryCreatePerm(data_directory_mode);
+
+	PQclear(res);
+	return true;
+}
+
+/*
+ * Run IDENTIFY_SYSTEM through a given connection and give back to caller
+ * some result information if requested:
+ * - System identifier
+ * - Current timeline ID
+ * - Start LSN position
+ * - Database name (NULL in servers prior to 9.4)
+ */
+bool
+RunIdentifySystem(PGconn *conn, char **sysid, TimeLineID *starttli,
+				  XLogRecPtr *startpos, char **db_name)
+{
+	PGresult   *res;
+	uint32		hi,
+				lo;
+
+	/* Check connection existence */
+	Assert(conn != NULL);
+
+	res = PQexec(conn, "IDENTIFY_SYSTEM");
+	if (PQresultStatus(res) != PGRES_TUPLES_OK)
+	{
+		pg_log_error("could not send replication command \"%s\": %s",
+					 "IDENTIFY_SYSTEM", PQerrorMessage(conn));
+
+		PQclear(res);
+		return false;
+	}
+	if (PQntuples(res) != 1 || PQnfields(res) < 3)
+	{
+		pg_log_error("could not identify system: got %d rows and %d fields, expected %d rows and %d or more fields",
+					 PQntuples(res), PQnfields(res), 1, 3);
+
+		PQclear(res);
+		return false;
+	}
+
+	/* Get system identifier */
+	if (sysid != NULL)
+		*sysid = pg_strdup(PQgetvalue(res, 0, 0));
+
+	/* Get timeline ID to start streaming from */
+	if (starttli != NULL)
+		*starttli = atoi(PQgetvalue(res, 0, 1));
+
+	/* Get LSN start position if necessary */
+	if (startpos != NULL)
+	{
+		if (sscanf(PQgetvalue(res, 0, 2), "%X/%X", &hi, &lo) != 2)
+		{
+			pg_log_error("could not parse write-ahead log location \"%s\"",
+						 PQgetvalue(res, 0, 2));
+
+			PQclear(res);
+			return false;
+		}
+		*startpos = ((uint64) hi) << 32 | lo;
+	}
+
+	/* Get database name, only available in 9.4 and newer versions */
+	if (db_name != NULL)
+	{
+		*db_name = NULL;
+		if (PQserverVersion(conn) >= 90400)
+		{
+			if (PQnfields(res) < 4)
+			{
+				pg_log_error("could not identify system: got %d rows and %d fields, expected %d rows and %d or more fields",
+							 PQntuples(res), PQnfields(res), 1, 4);
+
+				PQclear(res);
+				return false;
+			}
+			if (!PQgetisnull(res, 0, 3))
+				*db_name = pg_strdup(PQgetvalue(res, 0, 3));
+		}
+	}
+
+	PQclear(res);
+	return true;
+}
+
+/*
+ * Run READ_REPLICATION_SLOT through a given connection and give back to
+ * caller some result information if requested for this slot:
+ * - Start LSN position, InvalidXLogRecPtr if unknown.
+ * - Current timeline ID, 0 if unknown.
+ * Returns false on failure, and true otherwise.
+ */
+bool
+GetSlotInformation(PGconn *conn, const char *slot_name,
+				   XLogRecPtr *restart_lsn, TimeLineID *restart_tli)
+{
+	PGresult   *res;
+	PQExpBuffer query;
+	XLogRecPtr	lsn_loc = InvalidXLogRecPtr;
+	TimeLineID	tli_loc = 0;
+
+	if (restart_lsn)
+		*restart_lsn = lsn_loc;
+	if (restart_tli)
+		*restart_tli = tli_loc;
+
+	query = createPQExpBuffer();
+	appendPQExpBuffer(query, "READ_REPLICATION_SLOT %s", slot_name);
+	res = PQexec(conn, query->data);
+	destroyPQExpBuffer(query);
+
+	if (PQresultStatus(res) != PGRES_TUPLES_OK)
+	{
+		pg_log_error("could not send replication command \"%s\": %s",
+					 "READ_REPLICATION_SLOT", PQerrorMessage(conn));
+		PQclear(res);
+		return false;
+	}
+
+	/* The command should always return precisely one tuple and three fields */
+	if (PQntuples(res) != 1 || PQnfields(res) != 3)
+	{
+		pg_log_error("could not read replication slot \"%s\": got %d rows and %d fields, expected %d rows and %d fields",
+					 slot_name, PQntuples(res), PQnfields(res), 1, 3);
+		PQclear(res);
+		return false;
+	}
+
+	/*
+	 * When the slot doesn't exist, the command returns a tuple with NULL
+	 * values.  This checks only the slot type field.
+	 */
+	if (PQgetisnull(res, 0, 0))
+	{
+		pg_log_error("replication slot \"%s\" does not exist", slot_name);
+		PQclear(res);
+		return false;
+	}
+
+	/*
+	 * Note that this cannot happen as READ_REPLICATION_SLOT supports only
+	 * physical slots, but play it safe.
+	 */
+	if (strcmp(PQgetvalue(res, 0, 0), "physical") != 0)
+	{
+		pg_log_error("expected a physical replication slot, got type \"%s\" instead",
+					 PQgetvalue(res, 0, 0));
+		PQclear(res);
+		return false;
+	}
+
+	/* restart LSN */
+	if (!PQgetisnull(res, 0, 1))
+	{
+		uint32		hi,
+					lo;
+
+		if (sscanf(PQgetvalue(res, 0, 1), "%X/%X", &hi, &lo) != 2)
+		{
+			pg_log_error("could not parse restart_lsn \"%s\" for replication slot \"%s\"",
+						 PQgetvalue(res, 0, 1), slot_name);
+			PQclear(res);
+			return false;
+		}
+		lsn_loc = ((uint64) hi) << 32 | lo;
+	}
+
+	/* current TLI */
+	if (!PQgetisnull(res, 0, 2))
+		tli_loc = (TimeLineID) atol(PQgetvalue(res, 0, 2));
+
+	PQclear(res);
+
+	/* Assign results if requested */
+	if (restart_lsn)
+		*restart_lsn = lsn_loc;
+	if (restart_tli)
+		*restart_tli = tli_loc;
+
+	return true;
+}
+
+/*
+ * Create a replication slot for the given connection. This function
+ * returns true in case of success.
+ */
+bool
+CreateReplicationSlot(PGconn *conn, const char *slot_name, const char *plugin,
+					  bool is_temporary, bool is_physical, bool reserve_wal,
+					  bool slot_exists_ok, bool two_phase)
+{
+	PQExpBuffer query;
+	PGresult   *res;
+	bool		use_new_option_syntax = (PQserverVersion(conn) >= 150000);
+
+	query = createPQExpBuffer();
+
+	Assert((is_physical && plugin == NULL) ||
+		   (!is_physical && plugin != NULL));
+	Assert(!(two_phase && is_physical));
+	Assert(slot_name != NULL);
+
+	/* Build base portion of query */
+	appendPQExpBuffer(query, "CREATE_REPLICATION_SLOT \"%s\"", slot_name);
+	if (is_temporary)
+		appendPQExpBufferStr(query, " TEMPORARY");
+	if (is_physical)
+		appendPQExpBufferStr(query, " PHYSICAL");
+	else
+		appendPQExpBuffer(query, " LOGICAL \"%s\"", plugin);
+
+	/* Add any requested options */
+	if (use_new_option_syntax)
+		appendPQExpBufferStr(query, " (");
+	if (is_physical)
+	{
+		if (reserve_wal)
+			AppendPlainCommandOption(query, use_new_option_syntax,
+									 "RESERVE_WAL");
+	}
+	else
+	{
+		if (two_phase && PQserverVersion(conn) >= 150000)
+			AppendPlainCommandOption(query, use_new_option_syntax,
+									 "TWO_PHASE");
+
+		if (PQserverVersion(conn) >= 100000)
+		{
+			/* pg_recvlogical doesn't use an exported snapshot, so suppress */
+			if (use_new_option_syntax)
+				AppendStringCommandOption(query, use_new_option_syntax,
+										  "SNAPSHOT", "nothing");
+			else
+				AppendPlainCommandOption(query, use_new_option_syntax,
+										 "NOEXPORT_SNAPSHOT");
+		}
+	}
+	if (use_new_option_syntax)
+	{
+		/* Suppress option list if it would be empty, otherwise terminate */
+		if (query->data[query->len - 1] == '(')
+		{
+			query->len -= 2;
+			query->data[query->len] = '\0';
+		}
+		else
+			appendPQExpBufferChar(query, ')');
+	}
+
+	/* Now run the query */
+	res = PQexec(conn, query->data);
+	if (PQresultStatus(res) != PGRES_TUPLES_OK)
+	{
+		const char *sqlstate = PQresultErrorField(res, PG_DIAG_SQLSTATE);
+
+		if (slot_exists_ok &&
+			sqlstate &&
+			strcmp(sqlstate, ERRCODE_DUPLICATE_OBJECT) == 0)
+		{
+			destroyPQExpBuffer(query);
+			PQclear(res);
+			return true;
+		}
+		else
+		{
+			pg_log_error("could not send replication command \"%s\": %s",
+						 query->data, PQerrorMessage(conn));
+
+			destroyPQExpBuffer(query);
+			PQclear(res);
+			return false;
+		}
+	}
+
+	if (PQntuples(res) != 1 || PQnfields(res) != 4)
+	{
+		pg_log_error("could not create replication slot \"%s\": got %d rows and %d fields, expected %d rows and %d fields",
+					 slot_name,
+					 PQntuples(res), PQnfields(res), 1, 4);
+
+		destroyPQExpBuffer(query);
+		PQclear(res);
+		return false;
+	}
+
+	destroyPQExpBuffer(query);
+	PQclear(res);
+	return true;
+}
+
+/*
+ * Drop a replication slot for the given connection. This function
+ * returns true in case of success.
+ */
+bool
+DropReplicationSlot(PGconn *conn, const char *slot_name)
+{
+	PQExpBuffer query;
+	PGresult   *res;
+
+	Assert(slot_name != NULL);
+
+	query = createPQExpBuffer();
+
+	/* Build query */
+	appendPQExpBuffer(query, "DROP_REPLICATION_SLOT \"%s\"",
+					  slot_name);
+	res = PQexec(conn, query->data);
+	if (PQresultStatus(res) != PGRES_COMMAND_OK)
+	{
+		pg_log_error("could not send replication command \"%s\": %s",
+					 query->data, PQerrorMessage(conn));
+
+		destroyPQExpBuffer(query);
+		PQclear(res);
+		return false;
+	}
+
+	if (PQntuples(res) != 0 || PQnfields(res) != 0)
+	{
+		pg_log_error("could not drop replication slot \"%s\": got %d rows and %d fields, expected %d rows and %d fields",
+					 slot_name,
+					 PQntuples(res), PQnfields(res), 0, 0);
+
+		destroyPQExpBuffer(query);
+		PQclear(res);
+		return false;
+	}
+
+	destroyPQExpBuffer(query);
+	PQclear(res);
+	return true;
+}
+
+/*
+ * Append a "plain" option - one with no value - to a server command that
+ * is being constructed.
+ *
+ * In the old syntax, all options were parser keywords, so you could just
+ * write things like SOME_COMMAND OPTION1 OPTION2 'opt2value' OPTION3 42. The
+ * new syntax uses a comma-separated list surrounded by parentheses, so the
+ * equivalent is SOME_COMMAND (OPTION1, OPTION2 'optvalue', OPTION3 42).
+ */
+void
+AppendPlainCommandOption(PQExpBuffer buf, bool use_new_option_syntax,
+						 char *option_name)
+{
+	if (buf->len > 0 && buf->data[buf->len - 1] != '(')
+	{
+		if (use_new_option_syntax)
+			appendPQExpBufferStr(buf, ", ");
+		else
+			appendPQExpBufferChar(buf, ' ');
+	}
+
+	appendPQExpBuffer(buf, " %s", option_name);
+}
+
+/*
+ * Append an option with an associated string value to a server command that
+ * is being constructed.
+ *
+ * See comments for AppendPlainCommandOption, above.
+ */
+void
+AppendStringCommandOption(PQExpBuffer buf, bool use_new_option_syntax,
+						  char *option_name, char *option_value)
+{
+	AppendPlainCommandOption(buf, use_new_option_syntax, option_name);
+
+	if (option_value != NULL)
+	{
+		size_t		length = strlen(option_value);
+		char	   *escaped_value = palloc(1 + 2 * length);
+
+		PQescapeStringConn(conn, escaped_value, option_value, length, NULL);
+		appendPQExpBuffer(buf, " '%s'", escaped_value);
+		pfree(escaped_value);
+	}
+}
+
+/*
+ * Append an option with an associated integer value to a server command
+ * is being constructed.
+ *
+ * See comments for AppendPlainCommandOption, above.
+ */
+void
+AppendIntegerCommandOption(PQExpBuffer buf, bool use_new_option_syntax,
+						   char *option_name, int32 option_value)
+{
+	AppendPlainCommandOption(buf, use_new_option_syntax, option_name);
+
+	appendPQExpBuffer(buf, " %d", option_value);
+}
+
+/*
+ * Frontend version of GetCurrentTimestamp(), since we are not linked with
+ * backend code.
+ */
+TimestampTz
+feGetCurrentTimestamp(void)
+{
+	TimestampTz result;
+	struct timeval tp;
+
+	gettimeofday(&tp, NULL);
+
+	result = (TimestampTz) tp.tv_sec -
+		((POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY);
+	result = (result * USECS_PER_SEC) + tp.tv_usec;
+
+	return result;
+}
+
+/*
+ * Frontend version of TimestampDifference(), since we are not linked with
+ * backend code.
+ */
+void
+feTimestampDifference(TimestampTz start_time, TimestampTz stop_time,
+					  long *secs, int *microsecs)
+{
+	TimestampTz diff = stop_time - start_time;
+
+	if (diff <= 0)
+	{
+		*secs = 0;
+		*microsecs = 0;
+	}
+	else
+	{
+		*secs = (long) (diff / USECS_PER_SEC);
+		*microsecs = (int) (diff % USECS_PER_SEC);
+	}
+}
+
+/*
+ * Frontend version of TimestampDifferenceExceeds(), since we are not
+ * linked with backend code.
+ */
+bool
+feTimestampDifferenceExceeds(TimestampTz start_time,
+							 TimestampTz stop_time,
+							 int msec)
+{
+	TimestampTz diff = stop_time - start_time;
+
+	return (diff >= msec * INT64CONST(1000));
+}
+
+/*
+ * Converts an int64 to network byte order.
+ */
+void
+fe_sendint64(int64 i, char *buf)
+{
+	uint64		n64 = pg_hton64(i);
+
+	memcpy(buf, &n64, sizeof(n64));
+}
+
+/*
+ * Converts an int64 from network byte order to native format.
+ */
+int64
+fe_recvint64(char *buf)
+{
+	uint64		n64;
+
+	memcpy(&n64, buf, sizeof(n64));
+
+	return pg_ntoh64(n64);
+}