/src/bin/psql/command.c

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/*
 * psql - the PostgreSQL interactive terminal
 *
 * Copyright (c) 2000-2020, PostgreSQL Global Development Group
 *
 * src/bin/psql/command.c
 */
#include "postgres_fe.h"

#include <ctype.h>
#include <time.h>
#include <pwd.h>
#ifndef WIN32
#include <sys/stat.h>			/* for stat() */
#include <fcntl.h>				/* open() flags */
#include <unistd.h>				/* for geteuid(), getpid(), stat() */
#else
#include <win32.h>
#include <io.h>
#include <fcntl.h>
#include <direct.h>
#include <sys/stat.h>			/* for stat() */
#endif

#include "catalog/pg_class_d.h"
#include "command.h"
#include "common.h"
#include "common/logging.h"
#include "copy.h"
#include "crosstabview.h"
#include "describe.h"
#include "fe_utils/cancel.h"
#include "fe_utils/print.h"
#include "fe_utils/string_utils.h"
#include "help.h"
#include "input.h"
#include "large_obj.h"
#include "libpq-fe.h"
#include "mainloop.h"
#include "portability/instr_time.h"
#include "pqexpbuffer.h"
#include "psqlscanslash.h"
#include "settings.h"
#include "variables.h"

/*
 * Editable database object types.
 */
typedef enum EditableObjectType
{
	EditableFunction,
	EditableView
} EditableObjectType;

/* local function declarations */
static backslashResult exec_command(const char *cmd,
									PsqlScanState scan_state,
									ConditionalStack cstack,
									PQExpBuffer query_buf,
									PQExpBuffer previous_buf);
static backslashResult exec_command_a(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_C(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_connect(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_cd(PsqlScanState scan_state, bool active_branch,
									   const char *cmd);
static backslashResult exec_command_conninfo(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_copy(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_copyright(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_crosstabview(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_d(PsqlScanState scan_state, bool active_branch,
									  const char *cmd);
static backslashResult exec_command_edit(PsqlScanState scan_state, bool active_branch,
										 PQExpBuffer query_buf, PQExpBuffer previous_buf);
static backslashResult exec_command_ef_ev(PsqlScanState scan_state, bool active_branch,
										  PQExpBuffer query_buf, bool is_func);
static backslashResult exec_command_echo(PsqlScanState scan_state, bool active_branch,
										 const char *cmd);
static backslashResult exec_command_elif(PsqlScanState scan_state, ConditionalStack cstack,
										 PQExpBuffer query_buf);
static backslashResult exec_command_else(PsqlScanState scan_state, ConditionalStack cstack,
										 PQExpBuffer query_buf);
static backslashResult exec_command_endif(PsqlScanState scan_state, ConditionalStack cstack,
										  PQExpBuffer query_buf);
static backslashResult exec_command_encoding(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_errverbose(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_f(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_g(PsqlScanState scan_state, bool active_branch,
									  const char *cmd);
static backslashResult process_command_g_options(char *first_option,
												 PsqlScanState scan_state,
												 bool active_branch,
												 const char *cmd);
static backslashResult exec_command_gdesc(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_gexec(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_gset(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_help(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_html(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_include(PsqlScanState scan_state, bool active_branch,
											const char *cmd);
static backslashResult exec_command_if(PsqlScanState scan_state, ConditionalStack cstack,
									   PQExpBuffer query_buf);
static backslashResult exec_command_list(PsqlScanState scan_state, bool active_branch,
										 const char *cmd);
static backslashResult exec_command_lo(PsqlScanState scan_state, bool active_branch,
									   const char *cmd);
static backslashResult exec_command_out(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_print(PsqlScanState scan_state, bool active_branch,
										  PQExpBuffer query_buf, PQExpBuffer previous_buf);
static backslashResult exec_command_password(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_prompt(PsqlScanState scan_state, bool active_branch,
										   const char *cmd);
static backslashResult exec_command_pset(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_quit(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_reset(PsqlScanState scan_state, bool active_branch,
										  PQExpBuffer query_buf);
static backslashResult exec_command_s(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_set(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_setenv(PsqlScanState scan_state, bool active_branch,
										   const char *cmd);
static backslashResult exec_command_sf_sv(PsqlScanState scan_state, bool active_branch,
										  const char *cmd, bool is_func);
static backslashResult exec_command_t(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_T(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_timing(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_unset(PsqlScanState scan_state, bool active_branch,
										  const char *cmd);
static backslashResult exec_command_write(PsqlScanState scan_state, bool active_branch,
										  const char *cmd,
										  PQExpBuffer query_buf, PQExpBuffer previous_buf);
static backslashResult exec_command_watch(PsqlScanState scan_state, bool active_branch,
										  PQExpBuffer query_buf, PQExpBuffer previous_buf);
static backslashResult exec_command_x(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_z(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_shell_escape(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_slash_command_help(PsqlScanState scan_state, bool active_branch);
static char *read_connect_arg(PsqlScanState scan_state);
static PQExpBuffer gather_boolean_expression(PsqlScanState scan_state);
static bool is_true_boolean_expression(PsqlScanState scan_state, const char *name);
static void ignore_boolean_expression(PsqlScanState scan_state);
static void ignore_slash_options(PsqlScanState scan_state);
static void ignore_slash_filepipe(PsqlScanState scan_state);
static void ignore_slash_whole_line(PsqlScanState scan_state);
static bool is_branching_command(const char *cmd);
static void save_query_text_state(PsqlScanState scan_state, ConditionalStack cstack,
								  PQExpBuffer query_buf);
static void discard_query_text(PsqlScanState scan_state, ConditionalStack cstack,
							   PQExpBuffer query_buf);
static void copy_previous_query(PQExpBuffer query_buf, PQExpBuffer previous_buf);
static bool do_connect(enum trivalue reuse_previous_specification,
					   char *dbname, char *user, char *host, char *port);
static bool do_edit(const char *filename_arg, PQExpBuffer query_buf,
					int lineno, bool *edited);
static bool do_shell(const char *command);
static bool do_watch(PQExpBuffer query_buf, double sleep);
static bool lookup_object_oid(EditableObjectType obj_type, const char *desc,
							  Oid *obj_oid);
static bool get_create_object_cmd(EditableObjectType obj_type, Oid oid,
								  PQExpBuffer buf);
static int	strip_lineno_from_objdesc(char *obj);
static int	count_lines_in_buf(PQExpBuffer buf);
static void print_with_linenumbers(FILE *output, char *lines,
								   const char *header_keyword);
static void minimal_error_message(PGresult *res);

static void printSSLInfo(void);
static void printGSSInfo(void);
static bool printPsetInfo(const char *param, printQueryOpt *popt);
static char *pset_value_string(const char *param, printQueryOpt *popt);

#ifdef WIN32
static void checkWin32Codepage(void);
#endif



/*----------
 * HandleSlashCmds:
 *
 * Handles all the different commands that start with '\'.
 * Ordinarily called by MainLoop().
 *
 * scan_state is a lexer working state that is set to continue scanning
 * just after the '\'.  The lexer is advanced past the command and all
 * arguments on return.
 *
 * cstack is the current \if stack state.  This will be examined, and
 * possibly modified by conditional commands.
 *
 * query_buf contains the query-so-far, which may be modified by
 * execution of the backslash command (for example, \r clears it).
 *
 * previous_buf contains the query most recently sent to the server
 * (empty if none yet).  This should not be modified here, but some
 * commands copy its content into query_buf.
 *
 * query_buf and previous_buf will be NULL when executing a "-c"
 * command-line option.
 *
 * Returns a status code indicating what action is desired, see command.h.
 *----------
 */

backslashResult
HandleSlashCmds(PsqlScanState scan_state,
				ConditionalStack cstack,
				PQExpBuffer query_buf,
				PQExpBuffer previous_buf)
{
	backslashResult status;
	char	   *cmd;
	char	   *arg;

	Assert(scan_state != NULL);
	Assert(cstack != NULL);

	/* Parse off the command name */
	cmd = psql_scan_slash_command(scan_state);

	/* And try to execute it */
	status = exec_command(cmd, scan_state, cstack, query_buf, previous_buf);

	if (status == PSQL_CMD_UNKNOWN)
	{
		pg_log_error("invalid command \\%s", cmd);
		if (pset.cur_cmd_interactive)
			pg_log_info("Try \\? for help.");
		status = PSQL_CMD_ERROR;
	}

	if (status != PSQL_CMD_ERROR)
	{
		/*
		 * Eat any remaining arguments after a valid command.  We want to
		 * suppress evaluation of backticks in this situation, so transiently
		 * push an inactive conditional-stack entry.
		 */
		bool		active_branch = conditional_active(cstack);

		conditional_stack_push(cstack, IFSTATE_IGNORED);
		while ((arg = psql_scan_slash_option(scan_state,
											 OT_NORMAL, NULL, false)))
		{
			if (active_branch)
				pg_log_warning("\\%s: extra argument \"%s\" ignored", cmd, arg);
			free(arg);
		}
		conditional_stack_pop(cstack);
	}
	else
	{
		/* silently throw away rest of line after an erroneous command */
		while ((arg = psql_scan_slash_option(scan_state,
											 OT_WHOLE_LINE, NULL, false)))
			free(arg);
	}

	/* if there is a trailing \\, swallow it */
	psql_scan_slash_command_end(scan_state);

	free(cmd);

	/* some commands write to queryFout, so make sure output is sent */
	fflush(pset.queryFout);

	return status;
}


/*
 * Subroutine to actually try to execute a backslash command.
 *
 * The typical "success" result code is PSQL_CMD_SKIP_LINE, although some
 * commands return something else.  Failure results are PSQL_CMD_ERROR,
 * unless PSQL_CMD_UNKNOWN is more appropriate.
 */
static backslashResult
exec_command(const char *cmd,
			 PsqlScanState scan_state,
			 ConditionalStack cstack,
			 PQExpBuffer query_buf,
			 PQExpBuffer previous_buf)
{
	backslashResult status;
	bool		active_branch = conditional_active(cstack);

	/*
	 * In interactive mode, warn when we're ignoring a command within a false
	 * \if-branch.  But we continue on, so as to parse and discard the right
	 * amount of parameter text.  Each individual backslash command subroutine
	 * is responsible for doing nothing after discarding appropriate
	 * arguments, if !active_branch.
	 */
	if (pset.cur_cmd_interactive && !active_branch &&
		!is_branching_command(cmd))
	{
		pg_log_warning("\\%s command ignored; use \\endif or Ctrl-C to exit current \\if block",
					   cmd);
	}

	if (strcmp(cmd, "a") == 0)
		status = exec_command_a(scan_state, active_branch);
	else if (strcmp(cmd, "C") == 0)
		status = exec_command_C(scan_state, active_branch);
	else if (strcmp(cmd, "c") == 0 || strcmp(cmd, "connect") == 0)
		status = exec_command_connect(scan_state, active_branch);
	else if (strcmp(cmd, "cd") == 0)
		status = exec_command_cd(scan_state, active_branch, cmd);
	else if (strcmp(cmd, "conninfo") == 0)
		status = exec_command_conninfo(scan_state, active_branch);
	else if (pg_strcasecmp(cmd, "copy") == 0)
		status = exec_command_copy(scan_state, active_branch);
	else if (strcmp(cmd, "copyright") == 0)
		status = exec_command_copyright(scan_state, active_branch);
	else if (strcmp(cmd, "crosstabview") == 0)
		status = exec_command_crosstabview(scan_state, active_branch);
	else if (cmd[0] == 'd')
		status = exec_command_d(scan_state, active_branch, cmd);
	else if (strcmp(cmd, "e") == 0 || strcmp(cmd, "edit") == 0)
		status = exec_command_edit(scan_state, active_branch,
								   query_buf, previous_buf);
	else if (strcmp(cmd, "ef") == 0)
		status = exec_command_ef_ev(scan_state, active_branch, query_buf, true);
	else if (strcmp(cmd, "ev") == 0)
		status = exec_command_ef_ev(scan_state, active_branch, query_buf, false);
	else if (strcmp(cmd, "echo") == 0 || strcmp(cmd, "qecho") == 0 ||
			 strcmp(cmd, "warn") == 0)
		status = exec_command_echo(scan_state, active_branch, cmd);
	else if (strcmp(cmd, "elif") == 0)
		status = exec_command_elif(scan_state, cstack, query_buf);
	else if (strcmp(cmd, "else") == 0)
		status = exec_command_else(scan_state, cstack, query_buf);
	else if (strcmp(cmd, "endif") == 0)
		status = exec_command_endif(scan_state, cstack, query_buf);
	else if (strcmp(cmd, "encoding") == 0)
		status = exec_command_encoding(scan_state, active_branch);
	else if (strcmp(cmd, "errverbose") == 0)
		status = exec_command_errverbose(scan_state, active_branch);
	else if (strcmp(cmd, "f") == 0)
		status = exec_command_f(scan_state, active_branch);
	else if (strcmp(cmd, "g") == 0 || strcmp(cmd, "gx") == 0)
		status = exec_command_g(scan_state, active_branch, cmd);
	else if (strcmp(cmd, "gdesc") == 0)
		status = exec_command_gdesc(scan_state, active_branch);
	else if (strcmp(cmd, "gexec") == 0)
		status = exec_command_gexec(scan_state, active_branch);
	else if (strcmp(cmd, "gset") == 0)
		status = exec_command_gset(scan_state, active_branch);
	else if (strcmp(cmd, "h") == 0 || strcmp(cmd, "help") == 0)
		status = exec_command_help(scan_state, active_branch);
	else if (strcmp(cmd, "H") == 0 || strcmp(cmd, "html") == 0)
		status = exec_command_html(scan_state, active_branch);
	else if (strcmp(cmd, "i") == 0 || strcmp(cmd, "include") == 0 ||
			 strcmp(cmd, "ir") == 0 || strcmp(cmd, "include_relative") == 0)
		status = exec_command_include(scan_state, active_branch, cmd);
	else if (strcmp(cmd, "if") == 0)
		status = exec_command_if(scan_state, cstack, query_buf);
	else if (strcmp(cmd, "l") == 0 || strcmp(cmd, "list") == 0 ||
			 strcmp(cmd, "l+") == 0 || strcmp(cmd, "list+") == 0)
		status = exec_command_list(scan_state, active_branch, cmd);
	else if (strncmp(cmd, "lo_", 3) == 0)
		status = exec_command_lo(scan_state, active_branch, cmd);
	else if (strcmp(cmd, "o") == 0 || strcmp(cmd, "out") == 0)
		status = exec_command_out(scan_state, active_branch);
	else if (strcmp(cmd, "p") == 0 || strcmp(cmd, "print") == 0)
		status = exec_command_print(scan_state, active_branch,
									query_buf, previous_buf);
	else if (strcmp(cmd, "password") == 0)
		status = exec_command_password(scan_state, active_branch);
	else if (strcmp(cmd, "prompt") == 0)
		status = exec_command_prompt(scan_state, active_branch, cmd);
	else if (strcmp(cmd, "pset") == 0)
		status = exec_command_pset(scan_state, active_branch);
	else if (strcmp(cmd, "q") == 0 || strcmp(cmd, "quit") == 0)
		status = exec_command_quit(scan_state, active_branch);
	else if (strcmp(cmd, "r") == 0 || strcmp(cmd, "reset") == 0)
		status = exec_command_reset(scan_state, active_branch, query_buf);
	else if (strcmp(cmd, "s") == 0)
		status = exec_command_s(scan_state, active_branch);
	else if (strcmp(cmd, "set") == 0)
		status = exec_command_set(scan_state, active_branch);
	else if (strcmp(cmd, "setenv") == 0)
		status = exec_command_setenv(scan_state, active_branch, cmd);
	else if (strcmp(cmd, "sf") == 0 || strcmp(cmd, "sf+") == 0)
		status = exec_command_sf_sv(scan_state, active_branch, cmd, true);
	else if (strcmp(cmd, "sv") == 0 || strcmp(cmd, "sv+") == 0)
		status = exec_command_sf_sv(scan_state, active_branch, cmd, false);
	else if (strcmp(cmd, "t") == 0)
		status = exec_command_t(scan_state, active_branch);
	else if (strcmp(cmd, "T") == 0)
		status = exec_command_T(scan_state, active_branch);
	else if (strcmp(cmd, "timing") == 0)
		status = exec_command_timing(scan_state, active_branch);
	else if (strcmp(cmd, "unset") == 0)
		status = exec_command_unset(scan_state, active_branch, cmd);
	else if (strcmp(cmd, "w") == 0 || strcmp(cmd, "write") == 0)
		status = exec_command_write(scan_state, active_branch, cmd,
									query_buf, previous_buf);
	else if (strcmp(cmd, "watch") == 0)
		status = exec_command_watch(scan_state, active_branch,
									query_buf, previous_buf);
	else if (strcmp(cmd, "x") == 0)
		status = exec_command_x(scan_state, active_branch);
	else if (strcmp(cmd, "z") == 0)
		status = exec_command_z(scan_state, active_branch);
	else if (strcmp(cmd, "!") == 0)
		status = exec_command_shell_escape(scan_state, active_branch);
	else if (strcmp(cmd, "?") == 0)
		status = exec_command_slash_command_help(scan_state, active_branch);
	else
		status = PSQL_CMD_UNKNOWN;

	/*
	 * All the commands that return PSQL_CMD_SEND want to execute previous_buf
	 * if query_buf is empty.  For convenience we implement that here, not in
	 * the individual command subroutines.
	 */
	if (status == PSQL_CMD_SEND)
		copy_previous_query(query_buf, previous_buf);

	return status;
}


/*
 * \a -- toggle field alignment
 *
 * This makes little sense but we keep it around.
 */
static backslashResult
exec_command_a(PsqlScanState scan_state, bool active_branch)
{
	bool		success = true;

	if (active_branch)
	{
		if (pset.popt.topt.format != PRINT_ALIGNED)
			success = do_pset("format", "aligned", &pset.popt, pset.quiet);
		else
			success = do_pset("format", "unaligned", &pset.popt, pset.quiet);
	}

	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
}

/*
 * \C -- override table title (formerly change HTML caption)
 */
static backslashResult
exec_command_C(PsqlScanState scan_state, bool active_branch)
{
	bool		success = true;

	if (active_branch)
	{
		char	   *opt = psql_scan_slash_option(scan_state,
												 OT_NORMAL, NULL, true);

		success = do_pset("title", opt, &pset.popt, pset.quiet);
		free(opt);
	}
	else
		ignore_slash_options(scan_state);

	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
}

/*
 * \c or \connect -- connect to database using the specified parameters.
 *
 * \c [-reuse-previous=BOOL] dbname user host port
 *
 * Specifying a parameter as '-' is equivalent to omitting it.  Examples:
 *
 * \c - - hst		Connect to current database on current port of
 *					host "hst" as current user.
 * \c - usr - prt	Connect to current database on port "prt" of current host
 *					as user "usr".
 * \c dbs			Connect to database "dbs" on current port of current host
 *					as current user.
 */
static backslashResult
exec_command_connect(PsqlScanState scan_state, bool active_branch)
{
	bool		success = true;

	if (active_branch)
	{
		static const char prefix[] = "-reuse-previous=";
		char	   *opt1,
				   *opt2,
				   *opt3,
				   *opt4;
		enum trivalue reuse_previous = TRI_DEFAULT;

		opt1 = read_connect_arg(scan_state);
		if (opt1 != NULL && strncmp(opt1, prefix, sizeof(prefix) - 1) == 0)
		{
			bool		on_off;

			success = ParseVariableBool(opt1 + sizeof(prefix) - 1,
										"-reuse-previous",
										&on_off);
			if (success)
			{
				reuse_previous = on_off ? TRI_YES : TRI_NO;
				free(opt1);
				opt1 = read_connect_arg(scan_state);
			}
		}

		if (success)			/* give up if reuse_previous was invalid */
		{
			opt2 = read_connect_arg(scan_state);
			opt3 = read_connect_arg(scan_state);
			opt4 = read_connect_arg(scan_state);

			success = do_connect(reuse_previous, opt1, opt2, opt3, opt4);

			free(opt2);
			free(opt3);
			free(opt4);
		}
		free(opt1);
	}
	else
		ignore_slash_options(scan_state);

	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
}

/*
 * \cd -- change directory
 */
static backslashResult
exec_command_cd(PsqlScanState scan_state, bool active_branch, const char *cmd)
{
	bool		success = true;

	if (active_branch)
	{
		char	   *opt = psql_scan_slash_option(scan_state,
												 OT_NORMAL, NULL, true);
		char	   *dir;

		if (opt)
			dir = opt;
		else
		{
#ifndef WIN32
			struct passwd *pw;
			uid_t		user_id = geteuid();

			errno = 0;			/* clear errno before call */
			pw = getpwuid(user_id);
			if (!pw)
			{
				pg_log_error("could not get home directory for user ID %ld: %s",
							 (long) user_id,
							 errno ? strerror(errno) : _("user does not exist"));
				exit(EXIT_FAILURE);
			}
			dir = pw->pw_dir;
#else							/* WIN32 */

			/*
			 * On Windows, 'cd' without arguments prints the current
			 * directory, so if someone wants to code this here instead...
			 */
			dir = "/";
#endif							/* WIN32 */
		}

		if (chdir(dir) == -1)
		{
			pg_log_error("\\%s: could not change directory to \"%s\": %m",
						 cmd, dir);
			success = false;
		}

		if (opt)
			free(opt);
	}
	else
		ignore_slash_options(scan_state);

	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
}

/*
 * \conninfo -- display information about the current connection
 */
static backslashResult
exec_command_conninfo(PsqlScanState scan_state, bool active_branch)
{
	if (active_branch)
	{
		char	   *db = PQdb(pset.db);

		if (db == NULL)
			printf(_("You are currently not connected to a database.\n"));
		else
		{
			char	   *host = PQhost(pset.db);
			char	   *hostaddr = PQhostaddr(pset.db);

			/*
			 * If the host is an absolute path, the connection is via socket
			 * unless overridden by hostaddr
			 */
			if (is_absolute_path(host))
			{
				if (hostaddr && *hostaddr)
					printf(_("You are connected to database \"%s\" as user \"%s\" on address \"%s\" at port \"%s\".\n"),
						   db, PQuser(pset.db), hostaddr, PQport(pset.db));
				else
					printf(_("You are connected to database \"%s\" as user \"%s\" via socket in \"%s\" at port \"%s\".\n"),
						   db, PQuser(pset.db), host, PQport(pset.db));
			}
			else
			{
				if (hostaddr && *hostaddr && strcmp(host, hostaddr) != 0)
					printf(_("You are connected to database \"%s\" as user \"%s\" on host \"%s\" (address \"%s\") at port \"%s\".\n"),
						   db, PQuser(pset.db), host, hostaddr, PQport(pset.db));
				else
					printf(_("You are connected to database \"%s\" as user \"%s\" on host \"%s\" at port \"%s\".\n"),
						   db, PQuser(pset.db), host, PQport(pset.db));
			}
			printSSLInfo();
			printGSSInfo();
		}
	}

	return PSQL_CMD_SKIP_LINE;
}

/*
 * \copy -- run a COPY command
 */
static backslashResult
exec_command_copy(PsqlScanState scan_state, bool active_branch)
{
	bool		success = true;

	if (active_branch)
	{
		char	   *opt = psql_scan_slash_option(scan_state,
												 OT_WHOLE_LINE, NULL, false);

		success = do_copy(opt);
		free(opt);
	}
	else
		ignore_slash_whole_line(scan_state);

	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
}

/*
 * \copyright -- print copyright notice
 */
static backslashResult
exec_command_copyright(PsqlScanState scan_state, bool active_branch)
{
	if (active_branch)
		print_copyright();

	return PSQL_CMD_SKIP_LINE;
}

/*
 * \crosstabview -- execute a query and display results in crosstab
 */
static backslashResult
exec_command_crosstabview(PsqlScanState scan_state, bool active_branch)
{
	backslashResult status = PSQL_CMD_SKIP_LINE;

	if (active_branch)
	{
		int			i;

		for (i = 0; i < lengthof(pset.ctv_args); i++)
			pset.ctv_args[i] = psql_scan_slash_option(scan_state,
													  OT_NORMAL, NULL, true);
		pset.crosstab_flag = true;
		status = PSQL_CMD_SEND;
	}
	else
		ignore_slash_options(scan_state);

	return status;
}

/*
 * \d* commands
 */
static backslashResult
exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
{
	backslashResult status = PSQL_CMD_SKIP_LINE;
	bool		success = true;

	if (active_branch)
	{
		char	   *pattern;
		bool		show_verbose,
					show_system;

		/* We don't do SQLID reduction on the pattern yet */
		pattern = psql_scan_slash_option(scan_state,
										 OT_NORMAL, NULL, true);

		show_verbose = strchr(cmd, '+') ? true : false;
		show_system = strchr(cmd, 'S') ? true : false;

		switch (cmd[1])
		{
			case '\0':
			case '+':
			case 'S':
				if (pattern)
					success = describeTableDetails(pattern, show_verbose, show_system);
				else
					/* standard listing of interesting things */
					success = listTables("tvmsE", NULL, show_verbose, show_system);
				break;
			case 'A':
				{
					char	   *pattern2 = NULL;

					if (pattern && cmd[2] != '\0' && cmd[2] != '+')
						pattern2 = psql_scan_slash_option(scan_state, OT_NORMAL, NULL, true);

					switch (cmd[2])
					{
						case '\0':
						case '+':
							success = describeAccessMethods(pattern, show_verbose);
							break;
						case 'c':
							success = listOperatorClasses(pattern, pattern2, show_verbose);
							break;
						case 'f':
							success = listOperatorFamilies(pattern, pattern2, show_verbose);
							break;
						case 'o':
							success = listOpFamilyOperators(pattern, pattern2, show_verbose);
							break;
						case 'p':
							success = listOpFamilyProcedures(pattern, pattern2);
							break;
						default:
							status = PSQL_CMD_UNKNOWN;
							break;
					}

					if (pattern2)
						free(pattern2);
				}
				break;
			case 'a':
				success = describeAggregates(pattern, show_verbose, show_system);
				break;
			case 'b':
				success = describeTablespaces(pattern, show_verbose);
				break;
			case 'c':
				success = listConversions(pattern, show_verbose, show_system);
				break;
			case 'C':
				success = listCasts(pattern, show_verbose);
				break;
			case 'd':
				if (strncmp(cmd, "ddp", 3) == 0)
					success = listDefaultACLs(pattern);
				else
					success = objectDescription(pattern, show_system);
				break;
			case 'D':
				success = listDomains(pattern, show_verbose, show_system);
				break;
			case 'f':			/* function subsystem */
				switch (cmd[2])
				{
					case '\0':
					case '+':
					case 'S':
					case 'a':
					case 'n':
					case 'p':
					case 't':
					case 'w':
						success = describeFunctions(&cmd[2], pattern, show_verbose, show_system);
						break;
					default:
						status = PSQL_CMD_UNKNOWN;
						break;
				}
				break;
			case 'g':
				/* no longer distinct from \du */
				success = describeRoles(pattern, show_verbose, show_system);
				break;
			case 'l':
				success = do_lo_list();
				break;
			case 'L':
				success = listLanguages(pattern, show_verbose, show_system);
				break;
			case 'n':
				success = listSchemas(pattern, show_verbose, show_system);
				break;
			case 'o':
				success = describeOperators(pattern, show_verbose, show_system);
				break;
			case 'O':
				success = listCollations(pattern, show_verbose, show_system);
				break;
			case 'p':
				success = permissionsList(pattern);
				break;
			case 'P':
				{
					switch (cmd[2])
					{
						case '\0':
						case '+':
						case 't':
						case 'i':
						case 'n':
							success = listPartitionedTables(&cmd[2], pattern, show_verbose);
							break;
						default:
							status = PSQL_CMD_UNKNOWN;
							break;
					}
				}
				break;
			case 'T':
				success = describeTypes(pattern, show_verbose, show_system);
				break;
			case 't':
			case 'v':
			case 'm':
			case 'i':
			case 's':
			case 'E':
				success = listTables(&cmd[1], pattern, show_verbose, show_system);
				break;
			case 'r':
				if (cmd[2] == 'd' && cmd[3] == 's')
				{
					char	   *pattern2 = NULL;

					if (pattern)
						pattern2 = psql_scan_slash_option(scan_state,
														  OT_NORMAL, NULL, true);
					success = listDbRoleSettings(pattern, pattern2);

					if (pattern2)
						free(pattern2);
				}
				else
					status = PSQL_CMD_UNKNOWN;
				break;
			case 'R':
				switch (cmd[2])
				{
					case 'p':
						if (show_verbose)
							success = describePublications(pattern);
						else
							success = listPublications(pattern);
						break;
					case 's':
						success = describeSubscriptions(pattern, show_verbose);
						break;
					default:
						status = PSQL_CMD_UNKNOWN;
				}
				break;
			case 'u':
				success = describeRoles(pattern, show_verbose, show_system);
				break;
			case 'F':			/* text search subsystem */
				switch (cmd[2])
				{
					case '\0':
					case '+':
						success = listTSConfigs(pattern, show_verbose);
						break;
					case 'p':
						success = listTSParsers(pattern, show_verbose);
						break;
					case 'd':
						success = listTSDictionaries(pattern, show_verbose);
						break;
					case 't':
						success = listTSTemplates(pattern, show_verbose);
						break;
					default:
						status = PSQL_CMD_UNKNOWN;
						break;
				}
				break;
			case 'e':			/* SQL/MED subsystem */
				switch (cmd[2])
				{
					case 's':
						success = listForeignServers(pattern, show_verbose);
						break;
					case 'u':
						success = listUserMappings(pattern, show_verbose);
						break;
					case 'w':
						success = listForeignDataWrappers(pattern, show_verbose);
						break;
					case 't':
						success = listForeignTables(pattern, show_verbose);
						break;
					default:
						status = PSQL_CMD_UNKNOWN;
						break;
				}
				break;
			case 'x':			/* Extensions */
				if (show_verbose)
					success = listExtensionContents(pattern);
				else
					success = listExtensions(pattern);
				break;
			case 'y':			/* Event Triggers */
				success = listEventTriggers(pattern, show_verbose);
				break;
			default:
				status = PSQL_CMD_UNKNOWN;
		}

		if (pattern)
			free(pattern);
	}
	else
		ignore_slash_options(scan_state);

	if (!success)
		status = PSQL_CMD_ERROR;

	return status;
}

/*
 * \e or \edit -- edit the current query buffer, or edit a file and
 * make it the query buffer
 */
static backslashResult
exec_command_edit(PsqlScanState scan_state, bool active_branch,
				  PQExpBuffer query_buf, PQExpBuffer previous_buf)
{
	backslashResult status = PSQL_CMD_SKIP_LINE;

	if (active_branch)
	{
		if (!query_buf)
		{
			pg_log_error("no query buffer");
			status = PSQL_CMD_ERROR;
		}
		else
		{
			char	   *fname;
			char	   *ln = NULL;
			int			lineno = -1;

			fname = psql_scan_slash_option(scan_state,
										   OT_NORMAL, NULL, true);
			if (fname)
			{
				/* try to get separate lineno arg */
				ln = psql_scan_slash_option(scan_state,
											OT_NORMAL, NULL, true);
				if (ln == NULL)
				{
					/* only one arg; maybe it is lineno not fname */
					if (fname[0] &&
						strspn(fname, "0123456789") == strlen(fname))
					{
						/* all digits, so assume it is lineno */
						ln = fname;
						fname = NULL;
					}
				}
			}
			if (ln)
			{
				lineno = atoi(ln);
				if (lineno < 1)
				{
					pg_log_error("invalid line number: %s", ln);
					status = PSQL_CMD_ERROR;
				}
			}
			if (status != PSQL_CMD_ERROR)
			{
				expand_tilde(&fname);
				if (fname)
					canonicalize_path(fname);

				/* If query_buf is empty, recall previous query for editing */
				copy_previous_query(query_buf, previous_buf);

				if (do_edit(fname, query_buf, lineno, NULL))
					status = PSQL_CMD_NEWEDIT;
				else
					status = PSQL_CMD_ERROR;
			}
			if (fname)
				free(fname);
			if (ln)
				free(ln);
		}
	}
	else
		ignore_slash_options(scan_state);

	return status;
}

/*
 * \ef/\ev -- edit the named function/view, or
 * present a blank CREATE FUNCTION/VIEW template if no argument is given
 */
static backslashResult
exec_command_ef_ev(PsqlScanState scan_state, bool active_branch,
				   PQExpBuffer query_buf, bool is_func)
{
	backslashResult status = PSQL_CMD_SKIP_LINE;

	if (active_branch)
	{
		char	   *obj_desc = psql_scan_slash_option(scan_state,
													  OT_WHOLE_LINE,
													  NULL, true);
		int			lineno = -1;

		if (pset.sversion < (is_func ? 80400 : 70400))
		{
			char		sverbuf[32];

			formatPGVersionNumber(pset.sversion, false,
								  sverbuf, sizeof(sverbuf));
			if (is_func)
				pg_log_error("The server (version %s) does not support editing function source.",
							 sverbuf);
			else
				pg_log_error("The server (version %s) does not support editing view definitions.",
							 sverbuf);
			status = PSQL_CMD_ERROR;
		}
		else if (!query_buf)
		{
			pg_log_error("no query buffer");
			status = PSQL_CMD_ERROR;
		}
		else
		{
			Oid			obj_oid = InvalidOid;
			EditableObjectType eot = is_func ? EditableFunction : EditableView;

			lineno = strip_lineno_from_objdesc(obj_desc);
			if (lineno == 0)
			{
				/* error already reported */
				status = PSQL_CMD_ERROR;
			}
			else if (!obj_desc)
			{
				/* set up an empty command to fill in */
				resetPQExpBuffer(query_buf);
				if (is_func)
					appendPQExpBufferStr(query_buf,
										 "CREATE FUNCTION ( )\n"
										 " RETURNS \n"
										 " LANGUAGE \n"
										 " -- common options:  IMMUTABLE  STABLE  STRICT  SECURITY DEFINER\n"
										 "AS $function$\n"
										 "\n$function$\n");
				else
					appendPQExpBufferStr(query_buf,
										 "CREATE VIEW  AS\n"
										 " SELECT \n"
										 "  -- something...\n");
			}
			else if (!lookup_object_oid(eot, obj_desc, &obj_oid))
			{
				/* error already reported */
				status = PSQL_CMD_ERROR;
			}
			else if (!get_create_object_cmd(eot, obj_oid, query_buf))
			{
				/* error already reported */
				status = PSQL_CMD_ERROR;
			}
			else if (is_func && lineno > 0)
			{
				/*
				 * lineno "1" should correspond to the first line of the
				 * function body.  We expect that pg_get_functiondef() will
				 * emit that on a line beginning with "AS ", and that there
				 * can be no such line before the real start of the function
				 * body.  Increment lineno by the number of lines before that
				 * line, so that it becomes relative to the first line of the
				 * function definition.
				 */
				const char *lines = query_buf->data;

				while (*lines != '\0')
				{
					if (strncmp(lines, "AS ", 3) == 0)
						break;
					lineno++;
					/* find start of next line */
					lines = strchr(lines, '\n');
					if (!lines)
						break;
					lines++;
				}
			}
		}

		if (status != PSQL_CMD_ERROR)
		{
			bool		edited = false;

			if (!do_edit(NULL, query_buf, lineno, &edited))
				status = PSQL_CMD_ERROR;
			else if (!edited)
				puts(_("No changes"));
			else
				status = PSQL_CMD_NEWEDIT;
		}

		if (obj_desc)
			free(obj_desc);
	}
	else
		ignore_slash_whole_line(scan_state);

	return status;
}

/*
 * \echo, \qecho, and \warn -- echo arguments to stdout, query output, or stderr
 */
static backslashResult
exec_command_echo(PsqlScanState scan_state, bool active_branch, const char *cmd)
{
	if (active_branch)
	{
		char	   *value;
		char		quoted;
		bool		no_newline = false;
		bool		first = true;
		FILE	   *fout;

		if (strcmp(cmd, "qecho") == 0)
			fout = pset.queryFout;
		else if (strcmp(cmd, "warn") == 0)
			fout = stderr;
		else
			fout = stdout;

		while ((value = psql_scan_slash_option(scan_state,
											   OT_NORMAL, &quoted, false)))
		{
			if (first && !no_newline && !quoted && strcmp(value, "-n") == 0)
				no_newline = true;
			else
			{
				if (first)
					first = false;
				else
					fputc(' ', fout);
				fputs(value, fout);
			}
			free(value);
		}
		if (!no_newline)
			fputs("\n", fout);
	}
	else
		ignore_slash_options(scan_state);

	return PSQL_CMD_SKIP_LINE;
}

/*
 * \encoding -- set/show client side encoding
 */
static backslashResult
exec_command_encoding(PsqlScanState scan_state, bool active_branch)
{
	if (active_branch)
	{
		char	   *encoding = psql_scan_slash_option(scan_state,
													  OT_NORMAL, NULL, false);

		if (!encoding)
		{
			/* show encoding */
			puts(pg_encoding_to_char(pset.encoding));
		}
		else
		{
			/* set encoding */
			if (PQsetClientEncoding(pset.db, encoding) == -1)
				pg_log_error("%s: invalid encoding name or conversion procedure not found", encoding);
			else
			{
				/* save encoding info into psql internal data */
				pset.encoding = PQclientEncoding(pset.db);
				pset.popt.topt.encoding = pset.encoding;
				SetVariable(pset.vars, "ENCODING",
							pg_encoding_to_char(pset.encoding));
			}
			free(encoding);
		}
	}
	else
		ignore_slash_options(scan_state);

	return PSQL_CMD_SKIP_LINE;
}

/*
 * \errverbose -- display verbose message from last failed query
 */
static backslashResult
exec_command_errverbose(PsqlScanState scan_state, bool active_branch)
{
	if (active_branch)
	{
		if (pset.last_error_result)
		{
			char	   *msg;

			msg = PQresultVerboseErrorMessage(pset.last_error_result,
											  PQERRORS_VERBOSE,
											  PQSHOW_CONTEXT_ALWAYS);
			if (msg)
			{
				pg_log_error("%s", msg);
				PQfreemem(msg);
			}
			else
				puts(_("out of memory"));
		}
		else
			puts(_("There is no previous error."));
	}

	return PSQL_CMD_SKIP_LINE;
}

/*
 * \f -- change field separator
 */
static backslashResult
exec_command_f(PsqlScanState scan_state, bool active_branch)
{
	bool		success = true;

	if (active_branch)
	{
		char	   *fname = psql_scan_slash_option(scan_state,
												   OT_NORMAL, NULL, false);

		success = do_pset("fieldsep", fname, &pset.popt, pset.quiet);
		free(fname);
	}
	else
		ignore_slash_options(scan_state);

	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
}

/*
 * \g  [(pset-option[=pset-value] ...)] [filename/shell-command]
 * \gx [(pset-option[=pset-value] ...)] [filename/shell-command]
 *
 * Send the current query.  If pset options are specified, they are made
 * active just for this query.  If a filename or pipe command is given,
 * the query output goes there.  \gx implicitly sets "expanded=on" along
 * with any other pset options that are specified.
 */
static backslashResult
exec_command_g(PsqlScanState scan_state, bool active_branch, const char *cmd)
{
	backslashResult status = PSQL_CMD_SKIP_LINE;
	char	   *fname;

	/*
	 * Because the option processing for this is fairly complicated, we do it
	 * and then decide whether the branch is active.
	 */
	fname = psql_scan_slash_option(scan_state,
								   OT_FILEPIPE, NULL, false);

	if (fname && fname[0] == '(')
	{
		/* Consume pset options through trailing ')' ... */
		status = process_command_g_options(fname + 1, scan_state,
										   active_branch, cmd);
		free(fname);
		/* ... and again attempt to scan the filename. */
		fname = psql_scan_slash_option(scan_state,
									   OT_FILEPIPE, NULL, false);
	}

	if (status == PSQL_CMD_SKIP_LINE && active_branch)
	{
		if (!fname)
			pset.gfname = NULL;
		else
		{
			expand_tilde(&fname);
			pset.gfname = pg_strdup(fname);
		}
		if (strcmp(cmd, "gx") == 0)
		{
			/* save settings if not done already, then force expanded=on */
			if (pset.gsavepopt == NULL)
				pset.gsavepopt = savePsetInfo(&pset.popt);
			pset.popt.topt.expanded = 1;
		}
		status = PSQL_CMD_SEND;
	}

	free(fname);

	return status;
}

/*
 * Process parenthesized pset options for \g
 *
 * Note: okay to modify first_option, but not to free it; caller does that
 */
static backslashResult
process_command_g_options(char *first_option, PsqlScanState scan_state,
						  bool active_branch, const char *cmd)
{
	bool		success = true;
	bool		found_r_paren = false;

	do
	{
		char	   *option;
		size_t		optlen;

		/* If not first time through, collect a new option */
		if (first_option)
			option = first_option;
		else
		{
			option = psql_scan_slash_option(scan_state,
											OT_NORMAL, NULL, false);
			if (!option)
			{
				if (active_branch)
				{
					pg_log_error("\\%s: missing right parenthesis", cmd);
					success = false;
				}
				break;
			}
		}

		/* Check for terminating right paren, and remove it from string */
		optlen = strlen(option);
		if (optlen > 0 && option[optlen - 1] == ')')
		{
			option[--optlen] = '\0';
			found_r_paren = true;
		}

		/* If there was anything besides parentheses, parse/execute it */
		if (optlen > 0)
		{
			/* We can have either "name" or "name=value" */
			char	   *valptr = strchr(option, '=');

			if (valptr)
				*valptr++ = '\0';
			if (active_branch)
			{
				/* save settings if not done already, then apply option */
				if (pset.gsavepopt == NULL)
					pset.gsavepopt = savePsetInfo(&pset.popt);
				success &= do_pset(option, valptr, &pset.popt, true);
			}
		}

		/* Clean up after this option.  We should not free first_option. */
		if (first_option)
			first_option = NULL;
		else
			free(option);
	} while (!found_r_paren);

	/* If we failed after already changing some options, undo side-effects */
	if (!success && active_branch && pset.gsavepopt)
	{
		restorePsetInfo(&pset.popt, pset.gsavepopt);
		pset.gsavepopt = NULL;
	}

	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
}

/*
 * \gdesc -- describe query result
 */
static backslashResult
exec_command_gdesc(PsqlScanState scan_state, bool active_branch)
{
	backslashResult status = PSQL_CMD_SKIP_LINE;

	if (active_branch)
	{
		pset.gdesc_flag = true;
		status = PSQL_CMD_SEND;
	}

	return status;
}

/*
 * \gexec -- send query and execute each field of result
 */
static backslashResult
exec_command_gexec(PsqlScanState scan_state, bool active_branch)
{
	backslashResult status = PSQL_CMD_SKIP_LINE;

	if (active_branch)
	{
		pset.gexec_flag = true;
		status = PSQL_CMD_SEND;
	}

	return status;
}

/*
 * \gset [prefix] -- send query and store result into variables
 */
static backslashResult
exec_command_gset(PsqlScanState scan_state, bool active_branch)
{
	backslashResult status = PSQL_CMD_SKIP_LINE;

	if (active_branch)
	{
		char	   *prefix = psql_scan_slash_option(scan_state,
													OT_NORMAL, NULL, false);

		if (prefix)
			pset.gset_prefix = prefix;
		else
		{
			/* we must set a non-NULL prefix to trigger storing */
			pset.gset_prefix = pg_strdup("");
		}
		/* gset_prefix is freed later */
		status = PSQL_CMD_SEND;
	}
	else
		ignore_slash_options(scan_state);

	return status;
}

/*
 * \help [topic] -- print help about SQL commands
 */
static backslashResult
exec_command_help(PsqlScanState scan_state, bool active_branch)
{
	if (active_branch)
	{
		char	   *opt = psql_scan_slash_option(scan_state,
												 OT_WHOLE_LINE, NULL, false);
		size_t		len;

		/* strip any trailing spaces and semicolons */
		if (opt)
		{
			len = strlen(opt);
			while (len > 0 &&
				   (isspace((unsigned char) opt[len - 1])
					|| opt[len - 1] == ';'))
				opt[--len] = '\0';
		}

		helpSQL(opt, pset.popt.topt.pager);
		free(opt);
	}
	else
		ignore_slash_whole_line(scan_state);

	return PSQL_CMD_SKIP_LINE;
}

/*
 * \H and \html -- toggle HTML formatting
 */
static backslashResult
exec_command_html(PsqlScanState scan_state, bool active_branch)
{
	bool		success = true;

	if (active_branch)
	{
		if (pset.popt.topt.format != PRINT_HTML)
			success = do_pset("format", "html", &pset.popt, pset.quiet);
		else
			success = do_pset("format", "aligned", &pset.popt, pset.quiet);
	}

	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
}

/*
 * \i and \ir -- include a file
 */
static backslashResult
exec_command_include(PsqlScanState scan_state, bool active_branch, const char *cmd)
{
	bool		success = true;

	if (active_branch)
	{
		char	   *fname = psql_scan_slash_option(scan_state,
												   OT_NORMAL, NULL, true);

		if (!fname)
		{
			pg_log_error("\\%s: missing required argument", cmd);
			success = false;
		}
		else
		{
			bool		include_relative;

			include_relative = (strcmp(cmd, "ir") == 0
								|| strcmp(cmd, "include_relative") == 0);
			expand_tilde(&fname);
			success = (process_file(fname, include_relative) == EXIT_SUCCESS);
			free(fname);
		}
	}
	else
		ignore_slash_options(scan_state);

	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
}

/*
 * \if <expr> -- beginning of an \if..\endif block
 *
 * <expr> is parsed as a boolean expression.  Invalid expressions will emit a
 * warning and be treated as false.  Statements that follow a false expression
 * will be parsed but ignored.  Note that in the case where an \if statement
 * is itself within an inactive section of a block, then the entire inner
 * \if..\endif block will be parsed but ignored.
 */
static backslashResult
exec_command_if(PsqlScanState scan_state, ConditionalStack cstack,
				PQExpBuffer query_buf)
{
	if (conditional_active(cstack))
	{
		/*
		 * First, push a new active stack entry; this ensures that the lexer
		 * will perform variable substitution and backtick evaluation while
		 * scanning the expression.  (That should happen anyway, since we know
		 * we're in an active outer branch, but let's be sure.)
		 */
		conditional_stack_push(cstack, IFSTATE_TRUE);

		/* Remember current query state in case we need to restore later */
		save_query_text_state(scan_state, cstack, query_buf);

		/*
		 * Evaluate the expression; if it's false, change to inactive state.
		 */
		if (!is_true_boolean_expression(scan_state, "\\if expression"))
			conditional_stack_poke(cstack, IFSTATE_FALSE);
	}
	else
	{
		/*
		 * We're within an inactive outer branch, so this entire \if block
		 * will be ignored.  We don't want to evaluate the expression, so push
		 * the "ignored" stack state before scanning it.
		 */
		conditional_stack_push(cstack, IFSTATE_IGNORED);

		/* Remember current query state in case we need to restore later */
		save_query_text_state(scan_state, cstack, query_buf);

		ignore_boolean_expression(scan_state);
	}

	return PSQL_CMD_SKIP_LINE;
}

/*
 * \elif <expr> -- alternative branch in an \if..\endif block
 *
 * <expr> is evaluated the same as in \if <expr>.
 */
static backslashResult
exec_command_elif(PsqlScanState scan_state, ConditionalStack cstack,
				  PQExpBuffer query_buf)
{
	bool		success = true;

	switch (conditional_stack_peek(cstack))
	{
		case IFSTATE_TRUE:

			/*
			 * Just finished active branch of this \if block.  Update saved
			 * state so we will keep whatever data was put in query_buf by the
			 * active branch.
			 */
			save_query_text_state(scan_state, cstack, query_buf);

			/*
			 * Discard \elif expression and ignore the rest until \endif.
			 * Switch state before reading expression to ensure proper lexer
			 * behavior.
			 */
			conditional_stack_poke(cstack, IFSTATE_IGNORED);
			ignore_boolean_expression(scan_state);
			break;
		case IFSTATE_FALSE:

			/*
			 * Discard any query text added by the just-skipped branch.
			 */
			discard_query_text(scan_state, cstack, query_buf);

			/*
			 * Have not yet found a true expression in this \if block, so this
			 * might be the first.  We have to change state before examining
			 * the expression, or the lexer won't do the right thing.
			 */
			conditional_stack_poke(cstack, IFSTATE_TRUE);
			if (!is_true_boolean_expression(scan_state, "\\elif expression"))
				conditional_stack_poke(cstack, IFSTATE_FALSE);
			break;
		case IFSTATE_IGNORED:

			/*
			 * Discard any query text added by the just-skipped branch.
			 */
			discard_query_text(scan_state, cstack, query_buf);

			/*
			 * Skip expression and move on.  Either the \if block already had
			 * an active section, or whole block is being skipped.
			 */
			ignore_boolean_expression(scan_state);
			break;
		case IFSTATE_ELSE_TRUE:
		case IFSTATE_ELSE_FALSE:
			pg_log_error("\\elif: cannot occur after \\else");
			success = false;
			break;
		case IFSTATE_NONE:
			/* no \if to elif from */
			pg_log_error("\\elif: no matching \\if");
			success = false;
			break;
	}

	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
}

/*
 * \else -- final alternative in an \if..\endif block
 *
 * Statements within an \else branch will only be executed if
 * all previous \if and \elif expressions evaluated to false
 * and the block was not itself being ignored.
 */
static backslashResult
exec_command_else(PsqlScanState scan_state, ConditionalStack cstack,
				  PQExpBuffer query_buf)
{
	bool		success = true;

	switch (conditional_stack_peek(cstack))
	{
		case IFSTATE_TRUE:

			/*
			 * Just finished active branch of this \if block.  Update saved
			 * state so we will keep whatever data was put in query_buf by the
			 * active branch.
			 */
			save_query_text_state(scan_state, cstack, query_buf);

			/* Now skip the \else branch */
			conditional_stack_poke(cstack, IFSTATE_ELSE_FALSE);
			break;
		case IFSTATE_FALSE:

			/*
			 * Discard any query text added by the just-skipped branch.
			 */
			discard_query_text(scan_state, cstack, query_buf);

			/*
			 * We've not found any true \if or \elif expression, so execute
			 * the \else branch.
			 */
			conditional_stack_poke(cstack, IFSTATE_ELSE_TRUE);
			break;
		case IFSTATE_IGNORED:

			/*
			 * Discard any query text added by the just-skipped branch.
			 */
			discard_query_text(scan_state, cstack, query_buf);

			/*
			 * Either we previously processed the active branch of this \if,
			 * or the whole \if block is being skipped.  Either way, skip the
			 * \else branch.
			 */
			conditional_stack_poke(cstack, IFSTATE_ELSE_FALSE);
			break;
		case IFSTATE_ELSE_TRUE:
		case IFSTATE_ELSE_FALSE:
			pg_log_error("\\else: cannot occur after \\else");
			success = false;
			break;
		case IFSTATE_NONE:
			/* no \if to else from */
			pg_log_error("\\else: no matching \\if");
			success = false;
			break;
	}

	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
}

/*
 * \endif -- ends an \if...\endif block
 */
static backslashResult
exec_command_endif(PsqlScanState scan_state, ConditionalStack cstack,
				   PQExpBuffer query_buf)
{
	bool		success = …