fe-connect.c

关系型数据库 Postgresql 6.5.2

/*-------------------------------------------------------------------------
 *
 * fe-connect.c
 *	  functions related to setting up a connection to the backend
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /usr/local/cvsroot/pgsql/src/interfaces/libpq/fe-connect.c,v 1.98 1999/06/17 15:16:04 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "libpq-fe.h"
#include "libpq-int.h"
#include "fe-auth.h"
#include "postgres.h"

#include <stdlib.h>
#ifdef WIN32
#include "win32.h"
#else
#if !defined(NO_UNISTD_H)
#include <unistd.h>
#endif
#include <netdb.h>
#include <netinet/tcp.h>
#endif
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>				/* for isspace() */

#ifndef HAVE_STRDUP
#include "strdup.h"
#endif
#ifdef HAVE_CRYPT_H
#include <crypt.h>
#endif

#ifdef MULTIBYTE
#include "mb/pg_wchar.h"
#endif

static ConnStatusType connectDB(PGconn *conn);
static PGconn *makeEmptyPGconn(void);
static void freePGconn(PGconn *conn);
static void closePGconn(PGconn *conn);
static int	conninfo_parse(const char *conninfo, char *errorMessage);
static char *conninfo_getval(char *keyword);
static void conninfo_free(void);
static void defaultNoticeProcessor(void *arg, const char *message);

/* XXX Why is this not static? */
void		PQsetenv(PGconn *conn);

#define NOTIFYLIST_INITIAL_SIZE 10
#define NOTIFYLIST_GROWBY 10


/* ----------
 * Definition of the conninfo parameters and their fallback resources.
 * If Environment-Var and Compiled-in are specified as NULL, no
 * fallback is available. If after all no value can be determined
 * for an option, an error is returned.
 *
 * The values for dbname and user are treated special in conninfo_parse.
 * If the Compiled-in resource is specified as a NULL value, the
 * user is determined by fe_getauthname() and for dbname the user
 * name is copied.
 *
 * The Label and Disp-Char entries are provided for applications that
 * want to use PQconndefaults() to create a generic database connection
 * dialog. Disp-Char is defined as follows:
 *	   ""		Normal input field
 * ----------
 */
static PQconninfoOption PQconninfoOptions[] = {
/* ----------------------------------------------------------------- */
/*	  Option-name		Environment-Var Compiled-in		Current value	*/
/*						Label							Disp-Char		*/
/* ----------------- --------------- --------------- --------------- */
	/* "authtype" is ignored as it is no longer used. */
	{"authtype", "PGAUTHTYPE", DefaultAuthtype, NULL,
	"Database-Authtype", "", 20},

	{"user", "PGUSER", NULL, NULL,
	"Database-User", "", 20},

	{"password", "PGPASSWORD", DefaultPassword, NULL,
	"Database-Password", "", 20},

	{"dbname", "PGDATABASE", NULL, NULL,
	"Database-Name", "", 20},

	{"host", "PGHOST", NULL, NULL,
	"Database-Host", "", 40},

	{"port", "PGPORT", DEF_PGPORT, NULL,
	"Database-Port", "", 6},

	{"tty", "PGTTY", DefaultTty, NULL,
	"Backend-Debug-TTY", "D", 40},

	{"options", "PGOPTIONS", DefaultOption, NULL,
	"Backend-Debug-Options", "D", 40},
/* ----------------- --------------- --------------- --------------- */
	{NULL, NULL, NULL, NULL,
	NULL, NULL, 0}
};

static struct EnvironmentOptions
{
	const char *envName,
			   *pgName;
}			EnvironmentOptions[] =

{
	/* common user-interface settings */
	{
		"PGDATESTYLE", "datestyle"
	},
	{
		"PGTZ", "timezone"
	},
#ifdef MULTIBYTE
	{
		"PGCLIENTENCODING", "client_encoding"
	},
#endif
	/* internal performance-related settings */
	{
		"PGCOSTHEAP", "cost_heap"
	},
	{
		"PGCOSTINDEX", "cost_index"
	},
	{
		"PGGEQO", "geqo"
	},
	{
		NULL
	}
};

/* ----------------
 *		PQconnectdb
 *
 * establishes a connection to a postgres backend through the postmaster
 * using connection information in a string.
 *
 * The conninfo string is a list of
 *
 *	   option = value
 *
 * definitions. Value might be a single value containing no whitespaces
 * or a single quoted string. If a single quote should appear everywhere
 * in the value, it must be escaped with a backslash like \'
 *
 * Returns a PGconn* which is needed for all subsequent libpq calls
 * if the status field of the connection returned is CONNECTION_BAD,
 * then some fields may be null'ed out instead of having valid values
 * ----------------
 */
PGconn *
PQconnectdb(const char *conninfo)
{
	PGconn	   *conn;
	char	   *tmp;

	/* ----------
	 * Allocate memory for the conn structure
	 * ----------
	 */
	conn = makeEmptyPGconn();
	if (conn == NULL)
		return (PGconn *) NULL;

	/* ----------
	 * Parse the conninfo string and save settings in conn structure
	 * ----------
	 */
	if (conninfo_parse(conninfo, conn->errorMessage) < 0)
	{
		conn->status = CONNECTION_BAD;
		conninfo_free();
		return conn;
	}
	tmp = conninfo_getval("host");
	conn->pghost = tmp ? strdup(tmp) : NULL;
	tmp = conninfo_getval("port");
	conn->pgport = tmp ? strdup(tmp) : NULL;
	tmp = conninfo_getval("tty");
	conn->pgtty = tmp ? strdup(tmp) : NULL;
	tmp = conninfo_getval("options");
	conn->pgoptions = tmp ? strdup(tmp) : NULL;
	tmp = conninfo_getval("dbname");
	conn->dbName = tmp ? strdup(tmp) : NULL;
	tmp = conninfo_getval("user");
	conn->pguser = tmp ? strdup(tmp) : NULL;
	tmp = conninfo_getval("password");
	conn->pgpass = tmp ? strdup(tmp) : NULL;

	/* ----------
	 * Free the connection info - all is in conn now
	 * ----------
	 */
	conninfo_free();

	/* ----------
	 * Connect to the database
	 * ----------
	 */
	conn->status = connectDB(conn);

	return conn;
}

/* ----------------
 *		PQconndefaults
 *
 * Parse an empty string like PQconnectdb() would do and return the
 * address of the connection options structure. Using this function
 * an application might determine all possible options and their
 * current default values.
 * ----------------
 */
PQconninfoOption *
PQconndefaults(void)
{
	char		errorMessage[ERROR_MSG_LENGTH];

	conninfo_parse("", errorMessage);
	return PQconninfoOptions;
}

/* ----------------
 *		PQsetdbLogin
 *
 * establishes a connection to a postgres backend through the postmaster
 * at the specified host and port.
 *
 * returns a PGconn* which is needed for all subsequent libpq calls
 * if the status field of the connection returned is CONNECTION_BAD,
 * then some fields may be null'ed out instead of having valid values
 *
 *	Uses these environment variables:
 *
 *	  PGHOST	   identifies host to which to connect if <pghost> argument
 *				   is NULL or a null string.
 *
 *	  PGPORT	   identifies TCP port to which to connect if <pgport> argument
 *				   is NULL or a null string.
 *
 *	  PGTTY		   identifies tty to which to send messages if <pgtty> argument
 *				   is NULL or a null string.
 *
 *	  PGOPTIONS    identifies connection options if <pgoptions> argument is
 *				   NULL or a null string.
 *
 *	  PGUSER	   Postgres username to associate with the connection.
 *
 *	  PGPASSWORD   The user's password.
 *
 *	  PGDATABASE   name of database to which to connect if <pgdatabase>
 *				   argument is NULL or a null string
 *
 *	  None of the above need be defined.  There are defaults for all of them.
 *
 * To support "delimited identifiers" for database names, only convert
 * the database name to lower case if it is not surrounded by double quotes.
 * Otherwise, strip the double quotes but leave the reset of the string intact.
 * - thomas 1997-11-08
 *
 * ----------------
 */
PGconn *
PQsetdbLogin(const char *pghost, const char *pgport, const char *pgoptions, const char *pgtty, const char *dbName, const char *login, const char *pwd)
{
	PGconn	   *conn;
	char	   *tmp;

	/* An error message from some service we call. */
	bool		error = FALSE;

	/* We encountered an error that prevents successful completion */
	int			i;

	conn = makeEmptyPGconn();
	if (conn == NULL)
		return (PGconn *) NULL;

	if ((pghost == NULL) || pghost[0] == '\0')
	{
		if ((tmp = getenv("PGHOST")) != NULL)
			conn->pghost = strdup(tmp);
	}
	else
		conn->pghost = strdup(pghost);

	if ((pgport == NULL) || pgport[0] == '\0')
	{
		if ((tmp = getenv("PGPORT")) == NULL)
			tmp = DEF_PGPORT;
		conn->pgport = strdup(tmp);
	}
	else
		conn->pgport = strdup(pgport);

	if ((pgtty == NULL) || pgtty[0] == '\0')
	{
		if ((tmp = getenv("PGTTY")) == NULL)
			tmp = DefaultTty;
		conn->pgtty = strdup(tmp);
	}
	else
		conn->pgtty = strdup(pgtty);

	if ((pgoptions == NULL) || pgoptions[0] == '\0')
	{
		if ((tmp = getenv("PGOPTIONS")) == NULL)
			tmp = DefaultOption;
		conn->pgoptions = strdup(tmp);
	}
	else
		conn->pgoptions = strdup(pgoptions);

	if (login)
		conn->pguser = strdup(login);
	else if ((tmp = getenv("PGUSER")) != NULL)
		conn->pguser = strdup(tmp);
	else
		conn->pguser = fe_getauthname(conn->errorMessage);

	if (conn->pguser == NULL)
	{
		error = TRUE;
		sprintf(conn->errorMessage,
				"FATAL: PQsetdbLogin(): Unable to determine a Postgres username!\n");
	}

	if (pwd)
		conn->pgpass = strdup(pwd);
	else if ((tmp = getenv("PGPASSWORD")) != NULL)
		conn->pgpass = strdup(tmp);
	else
		conn->pgpass = strdup(DefaultPassword);

	if ((dbName == NULL) || dbName[0] == '\0')
	{
		if ((tmp = getenv("PGDATABASE")) != NULL)
			conn->dbName = strdup(tmp);
		else if (conn->pguser)
			conn->dbName = strdup(conn->pguser);
	}
	else
		conn->dbName = strdup(dbName);

	if (conn->dbName)
	{

		/*
		 * if the database name is surrounded by double-quotes, then don't
		 * convert case
		 */
		if (*conn->dbName == '"')
		{
			strcpy(conn->dbName, conn->dbName + 1);
			conn->dbName[strlen(conn->dbName) - 1] = '\0';
		}
		else
			for (i = 0; conn->dbName[i]; i++)
				if (isascii((unsigned char) conn->dbName[i]) &&
					isupper(conn->dbName[i]))
					conn->dbName[i] = tolower(conn->dbName[i]);
	}

	if (error)
		conn->status = CONNECTION_BAD;
	else
		conn->status = connectDB(conn);

	return conn;
}


/*
 * update_db_info -
 * get all additional infos out of dbName
 *
 */
static int
update_db_info(PGconn *conn)
{
	char	   *tmp,
			   *old = conn->dbName;

	if (strchr(conn->dbName, '@') != NULL)
	{
		/* old style: dbname[@server][:port] */
		tmp = strrchr(conn->dbName, ':');
		if (tmp != NULL)		/* port number given */
		{
			conn->pgport = strdup(tmp + 1);
			*tmp = '\0';
		}

		tmp = strrchr(conn->dbName, '@');
		if (tmp != NULL)		/* host name given */
		{
			conn->pghost = strdup(tmp + 1);
			*tmp = '\0';
		}

		conn->dbName = strdup(old);
		free(old);
	}
	else
	{
		int			offset;

		/*
		 * only allow protocols tcp and unix
		 */
		if (strncmp(conn->dbName, "tcp:", 4) == 0)
			offset = 4;
		else if (strncmp(conn->dbName, "unix:", 5) == 0)
			offset = 5;
		else
			return 0;

		if (strncmp(conn->dbName + offset, "postgresql://", strlen("postgresql://")) == 0)
		{

			/*
			 * new style:
			 * <tcp|unix>:postgresql://server[:port][/dbname][?options]
			 */
			offset += strlen("postgresql://");

			tmp = strrchr(conn->dbName + offset, '?');
			if (tmp != NULL)	/* options given */
			{
				conn->pgoptions = strdup(tmp + 1);
				*tmp = '\0';
			}

			tmp = strrchr(conn->dbName + offset, '/');
			if (tmp != NULL)	/* database name given */
			{
				conn->dbName = strdup(tmp + 1);
				*tmp = '\0';
			}
			else
			{
				if ((tmp = getenv("PGDATABASE")) != NULL)
					conn->dbName = strdup(tmp);
				else if (conn->pguser)
					conn->dbName = strdup(conn->pguser);
			}

			tmp = strrchr(old + offset, ':');
			if (tmp != NULL)	/* port number given */
			{
				conn->pgport = strdup(tmp + 1);
				*tmp = '\0';
			}

			if (strncmp(old, "unix:", 5) == 0)
			{
				conn->pghost = NULL;
				if (strcmp(old + offset, "localhost") != 0)
				{
					(void) sprintf(conn->errorMessage,
								   "connectDB() -- non-tcp access only possible on localhost\n");
					return 1;
				}
			}
			else
				conn->pghost = strdup(old + offset);

			free(old);
		}
	}

	return 0;
}

/*
 * connectDB -
 * make a connection to the backend so it is ready to receive queries.
 * return CONNECTION_OK if successful, CONNECTION_BAD if not.
 *
 */
static ConnStatusType
connectDB(PGconn *conn)
{
	PGresult   *res;
	struct hostent *hp;
	StartupPacket sp;
	AuthRequest areq;