postgresql/src/bin/psql/common.c

/*
 * psql - the PostgreSQL interactive terminal
 *
 * Copyright 2000 by PostgreSQL Global Development Group
 *
 * $Header: /cvsroot/pgsql/src/bin/psql/common.c,v 1.63 2003/06/12 07:52:51 momjian Exp $
 */
#include "postgres_fe.h"
#include "common.h"

#include <errno.h>
#include <stdarg.h>
#ifndef HAVE_STRDUP
#include <strdup.h>
#endif
#include <signal.h>
#ifndef WIN32
#include <sys/time.h>
#include <unistd.h>				/* for write() */
#include <setjmp.h>
#else
#include <io.h>					/* for _write() */
#include <win32.h>
#include <sys/timeb.h>			/* for _ftime() */
#endif

#include "libpq-fe.h"
#include "pqsignal.h"

#include "settings.h"
#include "variables.h"
#include "copy.h"
#include "prompt.h"
#include "print.h"
#include "mainloop.h"


/* Workarounds for Windows */
/* Probably to be moved up the source tree in the future, perhaps to be replaced by
 * more specific checks like configure-style HAVE_GETTIMEOFDAY macros.
 */
#ifndef WIN32

typedef struct timeval TimevalStruct;
#define GETTIMEOFDAY(T) gettimeofday(T, NULL)
#define DIFF_MSEC(T, U) ((((T)->tv_sec - (U)->tv_sec) * 1000000.0 + (T)->tv_usec - (U)->tv_usec) / 1000.0)

#else

typedef struct _timeb TimevalStruct;
#define GETTIMEOFDAY(T) _ftime(&T)
#define DIFF_MSEC(T, U) ((((T)->time - (U)->time) * 1000.0 + (T)->millitm - (U)->millitm))

#endif

extern bool prompt_state;

/*
 * "Safe" wrapper around strdup()
 */
char *
xstrdup(const char *string)
{
	char	   *tmp;

	if (!string)
	{
		fprintf(stderr, gettext("%s: xstrdup: cannot duplicate null pointer (internal error)\n"),
				pset.progname);
		exit(EXIT_FAILURE);
	}
	tmp = strdup(string);
	if (!tmp)
	{
		psql_error("out of memory\n");
		exit(EXIT_FAILURE);
	}
	return tmp;
}



/*
 * setQFout
 * -- handler for -o command line option and \o command
 *
 * Tries to open file fname (or pipe if fname starts with '|')
 * and stores the file handle in pset)
 * Upon failure, sets stdout and returns false.
 */
bool
setQFout(const char *fname)
{
	bool		status = true;

	/* Close old file/pipe */
	if (pset.queryFout && pset.queryFout != stdout && pset.queryFout != stderr)
	{
		if (pset.queryFoutPipe)
			pclose(pset.queryFout);
		else
			fclose(pset.queryFout);
	}

	/* If no filename, set stdout */
	if (!fname || fname[0] == '\0')
	{
		pset.queryFout = stdout;
		pset.queryFoutPipe = false;
	}
	else if (*fname == '|')
	{
		pset.queryFout = popen(fname + 1, "w");
		pset.queryFoutPipe = true;
	}
	else
	{
		pset.queryFout = fopen(fname, "w");
		pset.queryFoutPipe = false;
	}

	if (!(pset.queryFout))
	{
		psql_error("%s: %s\n", fname, strerror(errno));
		pset.queryFout = stdout;
		pset.queryFoutPipe = false;
		status = false;
	}

	/* Direct signals */
#ifndef WIN32
	pqsignal(SIGPIPE, pset.queryFoutPipe ? SIG_IGN : SIG_DFL);
#endif

	return status;
}



/*
 * Error reporting for scripts. Errors should look like
 *	 psql:filename:lineno: message
 *
 */
void
psql_error(const char *fmt,...)
{
	va_list		ap;

	fflush(stdout);
	if (pset.queryFout != stdout)
		fflush(pset.queryFout);

	if (pset.inputfile)
		fprintf(stderr, "%s:%s:%u: ", pset.progname, pset.inputfile, pset.lineno);
	va_start(ap, fmt);
	vfprintf(stderr, gettext(fmt), ap);
	va_end(ap);
}



/*
 * for backend Notice messages (INFO, WARNING, etc)
 */
void
NoticeProcessor(void *arg, const char *message)
{
	(void) arg;					/* not used */
	psql_error("%s", message);
}



/*
 * Code to support query cancellation
 *
 * Before we start a query, we enable a SIGINT signal catcher that sends a
 * cancel request to the backend. Note that sending the cancel directly from
 * the signal handler is safe because PQrequestCancel() is written to make it
 * so. We use write() to print to stdout because it's better to use simple
 * facilities in a signal handler.
 */
static PGconn	   *volatile cancelConn = NULL;

volatile bool cancel_pressed = false;


#ifndef WIN32

#define write_stderr(String) write(fileno(stderr), String, strlen(String))

void
handle_sigint(SIGNAL_ARGS)
{
	int			save_errno = errno;

	/* Don't muck around if copying in or prompting for a password. */
	if ((copy_in_state && pset.cur_cmd_interactive) || prompt_state)
		return;

	if (cancelConn == NULL)
		siglongjmp(main_loop_jmp, 1);

	cancel_pressed = true;

	if (PQrequestCancel(cancelConn))
		write_stderr("Cancel request sent\n");
	else
	{
		write_stderr("Could not send cancel request: ");
		write_stderr(PQerrorMessage(cancelConn));
	}
	errno = save_errno;			/* just in case the write changed it */
}
#endif   /* not WIN32 */



/* ConnectionUp
 *
 * Returns whether our backend connection is still there.
 */
static bool 
ConnectionUp()
{
	return PQstatus(pset.db) != CONNECTION_BAD;
}



/* CheckConnection
 *
 * Verify that we still have a good connection to the backend, and if not,
 * see if it can be restored.
 *
 * Returns true if either the connection was still there, or it could be
 * restored successfully; false otherwise.  If, however, there was no
 * connection and the session is non-interactive, this will exit the program
 * with a code of EXIT_BADCONN.
 */
static bool
CheckConnection()
{
	bool OK;
	
	OK = ConnectionUp();
	if (!OK)
	{
		if (!pset.cur_cmd_interactive)
		{
			psql_error("connection to server was lost\n");
			exit(EXIT_BADCONN);
		}

		fputs(gettext("The connection to the server was lost. Attempting reset: "), stderr);
		PQreset(pset.db);
		OK = ConnectionUp();
		if (!OK)
		{
			fputs(gettext("Failed.\n"), stderr);
			PQfinish(pset.db);
			pset.db = NULL;
			ResetCancelConn();
			SetVariable(pset.vars, "DBNAME", NULL);
			SetVariable(pset.vars, "HOST", NULL);
			SetVariable(pset.vars, "PORT", NULL);
			SetVariable(pset.vars, "USER", NULL);
			SetVariable(pset.vars, "ENCODING", NULL);
		}
		else
			fputs(gettext("Succeeded.\n"), stderr);
	}

	return OK;
}



/*
 * SetCancelConn
 *
 * Set cancelConn to point to the current database connection.
 */
static void SetCancelConn(void)
{
  cancelConn = pset.db;
}


/*
 * ResetCancelConn
 *
 * Set cancelConn to NULL.  I don't know what this means exactly, but it saves
 * having to export the variable.
 */
void ResetCancelConn(void)
{
  cancelConn = NULL;
}


/*
 * AcceptResult
 *
 * Checks whether a result is valid, giving an error message if necessary;
 * (re)sets copy_in_state and cancelConn as needed, and ensures that the
 * connection to the backend is still up.
 *
 * Returns true for valid result, false for error state.
 */
static bool
AcceptResult(const PGresult *result)
{
	bool OK = true;

	ResetCancelConn();

	if (!result)
	{
	  OK = false;
	}
	else switch (PQresultStatus(result))
	{
	  case PGRES_COPY_IN:
		 copy_in_state = true;
		 break;

	  case PGRES_COMMAND_OK:
	  case PGRES_TUPLES_OK:
		 /* Fine, do nothing */
		 break;

	  case PGRES_COPY_OUT:
		 /* keep cancel connection for copy out state */
		 SetCancelConn();
		 break;

	  default:
		 OK = false;
		 break;
	}

	if (!OK) 
	{
		CheckConnection();
		psql_error("%s", PQerrorMessage(pset.db));
	}

	return OK;
}



/*
 * PSQLexec
 *
 * This is the way to send "backdoor" queries (those not directly entered
 * by the user). It is subject to -E but not -e.
 *
 * If the given querystring generates multiple PGresults, normally the last
 * one is returned to the caller.  However, if ignore_command_ok is TRUE,
 * then PGresults with status PGRES_COMMAND_OK are ignored.  This is intended
 * mainly to allow locutions such as "begin; select ...; commit".
 */
PGresult *
PSQLexec(const char *query, bool ignore_command_ok)
{
	PGresult   *res = NULL;
	PGresult   *newres;
	int	echo_hidden;
	ExecStatusType rstatus;

	if (!pset.db)
	{
		psql_error("You are currently not connected to a database.\n");
		return NULL;
	}

	echo_hidden = SwitchVariable(pset.vars, "ECHO_HIDDEN", "noexec", NULL);
	if (echo_hidden != var_notset)
	{
		printf("********* QUERY **********\n"
			   "%s\n"
			   "**************************\n\n", query);
		fflush(stdout);

		if (echo_hidden == 1)
		return NULL;
	}

	/* discard any uneaten results of past queries */
	while ((newres = PQgetResult(pset.db)) != NULL)
		PQclear(newres);

	SetCancelConn();
	if (!PQsendQuery(pset.db, query))
	{
	  psql_error("%s", PQerrorMessage(pset.db));
	  ResetCancelConn();
	  return NULL;
	}

	rstatus = PGRES_EMPTY_QUERY;

	while (rstatus != PGRES_COPY_IN &&
			 rstatus != PGRES_COPY_OUT &&
			 (newres = PQgetResult(pset.db)))
		{
			rstatus = PQresultStatus(newres);
		if (!ignore_command_ok || rstatus != PGRES_COMMAND_OK)
			{
		  PGresult *tempRes = res;
			res = newres;
		  newres = tempRes;
		}
		PQclear(newres);
	}

	if (!AcceptResult(res) && res)
	{
		PQclear(res);
		res = NULL;
		}

	return res;
}



/*
 * PrintNotifications: check for asynchronous notifications, and print them out
 *
 */
static void
PrintNotifications(void)
{
	PGnotify   *notify;

	while ((notify = PQnotifies(pset.db)))
	{
		fprintf(pset.queryFout, gettext("Asynchronous NOTIFY '%s' from backend with pid %d received.\n"),
				notify->relname, notify->be_pid);
		PQfreemem(notify);
		fflush(pset.queryFout);
	}
}


/*
 * PrintQueryTuples: assuming query result is OK, print its tuples
 *
 * Returns true if successful, false otherwise.
 */
static bool 
PrintQueryTuples(const PGresult *results)
{
				/* write output to \g argument, if any */
				if (pset.gfname)
				{
					FILE	   *queryFout_copy = pset.queryFout;
					bool		queryFoutPipe_copy = pset.queryFoutPipe;

					pset.queryFout = stdout;	/* so it doesn't get
												 * closed */

					/* open file/pipe */
					if (!setQFout(pset.gfname))
					{
						pset.queryFout = queryFout_copy;
						pset.queryFoutPipe = queryFoutPipe_copy;
			return false;
					}

					printQuery(results, &pset.popt, pset.queryFout);

					/* close file/pipe, restore old setting */
					setQFout(NULL);

					pset.queryFout = queryFout_copy;
					pset.queryFoutPipe = queryFoutPipe_copy;

					free(pset.gfname);
					pset.gfname = NULL;
				}
				else
				{
					printQuery(results, &pset.popt, pset.queryFout);
				}

	return true;
}



/*
 * PrintQueryResults: analyze query results and print them out
 *
 * Note: Utility function for use by SendQuery() only.
 *
 * Returns true if the query executed successfully, false otherwise.
 */
static bool
PrintQueryResults(PGresult *results, 
		const TimevalStruct *before, 
		const TimevalStruct *after)
{
	bool	success = false;

	if (!results) 
	  return false;

	switch (PQresultStatus(results))
	{
		case PGRES_TUPLES_OK:
			success = PrintQueryTuples(results);
				break;
			case PGRES_EMPTY_QUERY:
				success = true;
				break;
			case PGRES_COMMAND_OK:
				{
					char		buf[10];

					success = true;
					sprintf(buf, "%u", (unsigned int) PQoidValue(results));
					if (!QUIET())
						{
							if (pset.popt.topt.format == PRINT_HTML)
							{
								fputs("<p>", pset.queryFout);
								html_escaped_print(PQcmdStatus(results), pset.queryFout);
								fputs("</p>\n", pset.queryFout);
							}
							else
							{
								fprintf(pset.queryFout, "%s\n", PQcmdStatus(results));
							}
						}
					SetVariable(pset.vars, "LASTOID", buf);
					break;
				}
			case PGRES_COPY_OUT:
				success = handleCopyOut(pset.db, pset.queryFout);
				break;

			case PGRES_COPY_IN:
				if (pset.cur_cmd_interactive && !QUIET())
					puts(gettext("Enter data to be copied followed by a newline.\n"
								 "End with a backslash and a period on a line by itself."));

				success = handleCopyIn(pset.db, pset.cur_cmd_source,
									   pset.cur_cmd_interactive ? get_prompt(PROMPT_COPY) : NULL);
				break;

		default:
				break;
		}

		fflush(pset.queryFout);

	if (!CheckConnection()) return false;

	/* Possible microtiming output */
	if (pset.timing && success)
		printf(gettext("Time: %.2f ms\n"), DIFF_MSEC(after, before));

	return success;
}



/*
 * SendQuery: send the query string to the backend
 * (and print out results)
 *
 * Note: This is the "front door" way to send a query. That is, use it to
 * send queries actually entered by the user. These queries will be subject to
 * single step mode.
 * To send "back door" queries (generated by slash commands, etc.) in a
 * controlled way, use PSQLexec().
 *
 * Returns true if the query executed successfully, false otherwise.
 */
bool
SendQuery(const char *query)
{
	PGresult   *results;
	TimevalStruct before, after;
	bool OK;

	if (!pset.db)
	{
		psql_error("You are currently not connected to a database.\n");
		return false;
	}

	if (GetVariableBool(pset.vars, "SINGLESTEP"))
	{
		char		buf[3];

		printf(gettext("***(Single step mode: Verify query)*********************************************\n"
					   "%s\n"
					   "***(press return to proceed or enter x and return to cancel)********************\n"),
			   query);
		fflush(stdout);
		if (fgets(buf, sizeof(buf), stdin) != NULL)
			if (buf[0] == 'x')
				return false;
	}
	else if (VariableEquals(pset.vars, "ECHO", "queries"))
		puts(query);

	SetCancelConn();

	if (pset.timing)
		GETTIMEOFDAY(&before);
	results = PQexec(pset.db, query);
	if (pset.timing)
		GETTIMEOFDAY(&after);

	OK = (AcceptResult(results) && PrintQueryResults(results, &before, &after));
	PQclear(results);

	PrintNotifications();
	return OK;
}


char parse_char(char **buf)
{
  long l;

  l = strtol(*buf, buf, 0);
  --*buf;
  return (char)l;
}