dbutil.c

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/* FreeTDS - Library of routines accessing Sybase and Microsoft databases
 * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004  Brian Bruns
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
 
#include <config.h>
 
#include <stdarg.h>
#include <stdio.h>
#include <assert.h>
 
#if HAVE_STDLIB_H
#include <stdlib.h>
#endif /* HAVE_STDLIB_H */
 
#if HAVE_ERRNO_H
# include <errno.h>
#endif /* HAVE_ERRNO_H */
 
#include <freetds/tds.h>
#include <freetds/convert.h>
#include <sybdb.h>
#include <syberror.h>
#include <dblib.h>
 
/*
 * test include consistency 
 * I don't think all compiler are able to compile this code... if not comment it
 */
#if ENABLE_EXTRA_CHECKS
 
/* TODO test SYBxxx consistency */
 
#define TEST_ATTRIBUTE(t,sa,fa,sb,fb) \
    TDS_COMPILE_CHECK(t,sizeof(((sa*)0)->fa) == sizeof(((sb*)0)->fb) && TDS_OFFSET(sa,fa) == TDS_OFFSET(sb,fb))
 
TEST_ATTRIBUTE(t21,TDS_MONEY4,mny4,DBMONEY4,mny4);
TEST_ATTRIBUTE(t22,TDS_OLD_MONEY,mnyhigh,DBMONEY,mnyhigh);
TEST_ATTRIBUTE(t23,TDS_OLD_MONEY,mnylow,DBMONEY,mnylow);
TEST_ATTRIBUTE(t24,TDS_DATETIME,dtdays,DBDATETIME,dtdays);
TEST_ATTRIBUTE(t25,TDS_DATETIME,dttime,DBDATETIME,dttime);
TEST_ATTRIBUTE(t26,TDS_DATETIME4,days,DBDATETIME4,days);
TEST_ATTRIBUTE(t27,TDS_DATETIME4,minutes,DBDATETIME4,minutes);
TEST_ATTRIBUTE(t28,TDS_NUMERIC,precision,DBNUMERIC,precision);
TEST_ATTRIBUTE(t29,TDS_NUMERIC,scale,DBNUMERIC,scale);
TEST_ATTRIBUTE(t30,TDS_NUMERIC,array,DBNUMERIC,array);
#endif
 
/* 
 * The next 2 functions receive the info and error messages that come from the TDS layer.  
 * The address of this function is passed to the TDS layer in dbinit().  
 * It takes a pointer to a DBPROCESS, it's just that the TDS layer didn't 
 * know what it really was.  
 */
int
_dblib_handle_info_message(const TDSCONTEXT * tds_ctx, TDSSOCKET * tds, TDSMESSAGE * msg)
{
    DBPROCESS *dbproc = (tds && tds_get_parent(tds))? (DBPROCESS *) tds_get_parent(tds) : NULL;
 
    tdsdump_log(TDS_DBG_FUNC, "_dblib_handle_info_message(%p, %p, %p)\n", tds_ctx, tds, msg);
    tdsdump_log(TDS_DBG_FUNC, "msgno %d: \"%s\"\n", msg->msgno, msg->message);
 
    /* 
     * Check to see if the user supplied a function, else ignore the message. 
     */
    if (_dblib_msg_handler) {
        _dblib_msg_handler(dbproc,
                   msg->msgno,
                   msg->state,
                   msg->severity, msg->message, msg->server, msg->proc_name, msg->line_number);
    }
 
    if (msg->severity > 10 && _dblib_err_handler) { /* call the application's error handler, if installed. */
        /*
         * Sybase docs say SYBESMSG is generated only in specific
         * cases (severity greater than 16, or deadlock occurred, or
         * a syntax error occurred.)  However, actual observed
         * behavior is that SYBESMSG is always generated for
         * server messages with severity greater than 10.
         */
        /* Cannot call dbperror() here because server messsage numbers (and text) are not in its lookup table. */
        static const char message[] = "General SQL Server error: Check messages from the SQL Server";
        (*_dblib_err_handler)(dbproc, msg->severity, SYBESMSG, DBNOERR, (char *) message, NULL);
    }
    return TDS_SUCCESS;
}
 
/** \internal
 *  \dblib_internal
 *  \brief handle errors generated by libtds
 *  \param tds_ctx actually a dbproc: contains all information needed by db-lib to manage communications with the server.
 *  \param tds contains all information needed by libtds to manage communications with the server.
 *  \param msg the message to send
 *  \returns 
 *  \remarks This function is called by libtds via tds_ctx->err_handler.  It exists to convert the db-lib 
 *  error handler's return code into one that libtds will know  how to handle.  
 *  libtds conveniently issues msgno's with the same values and meanings as db-lib and ODBC use.  
 *  (N.B. ODBC actually uses db-lib msgno numbers for its driver-specific "server errors".    
 */
/* 
 * Stack:
 *      libtds
 *          tds_ctx->err_handler (pointer to _dblib_handle_err_message)
 *          _dblib_handle_err_message
 *              dbperror
 *                  client (or default) error handler
 *                  returns db-lib defined return code INT_something.
 *              returns db-lib return code with Sybase semantics (adjusting client's code if need be)
 *          returns libtds return code
 *      decides what to do based on the universal libtds return code, thank you. 
 */ 
int
_dblib_handle_err_message(const TDSCONTEXT * tds_ctx, TDSSOCKET * tds, TDSMESSAGE * msg)
{
    DBPROCESS *dbproc = (tds && tds_get_parent(tds))? (DBPROCESS *) tds_get_parent(tds) : NULL;
    int rc = INT_CANCEL;
 
    assert(_dblib_err_handler);
    assert(msg);
 
    rc = dbperror(dbproc, msg->msgno, msg->oserr);
 
    /*
     * Preprocess the return code to handle INT_TIMEOUT/INT_CONTINUE
     * for non-SYBETIME errors in the strange and different ways as
     * specified by Sybase and Microsoft.
     */
    if (msg->msgno != SYBETIME) {
        switch (rc) {
        case INT_TIMEOUT:
            rc = INT_EXIT;
            break;
        case INT_CONTINUE:
            if (!dbproc || !dbproc->msdblib) {
                /* Sybase behavior */
                assert(0);  /* dbperror() should prevent */
                rc = INT_EXIT;
            } else {
                /* Microsoft behavior */
                rc = INT_CANCEL;
            }
            break;
        default:
            break;
        }
    }
 
    /*
     * Convert db-lib return code to libtds return code, and return.
     */
    switch (rc) {
    case INT_CANCEL:    return TDS_INT_CANCEL;
    case INT_TIMEOUT:   return TDS_INT_TIMEOUT;
    case INT_CONTINUE:  return TDS_INT_CONTINUE;
    
    case INT_EXIT:
        assert(0);  /* dbperror() should prevent */
    default:
        /* unknown return code from error handler */
        exit(EXIT_FAILURE);
        break;
    }
 
    /* not reached */
    assert(0);
    return TDS_INT_CANCEL;
}
 
/**
 * \ingroup dblib_internal
 * \brief check interrupts for libtds.
 * 
 * \param vdbproc a DBPROCESS pointer, contains all information needed by db-lib to manage communications with the server.
 * \sa DBDEAD(), dbsetinterrupt().
 */
int
_dblib_check_and_handle_interrupt(void * vdbproc)
{
    DBPROCESS * dbproc = (DBPROCESS*) vdbproc;
    int ret = INT_CONTINUE;
 
    assert( dbproc != NULL );
 
    if (dbproc->chkintr == NULL || dbproc->hndlintr == NULL)
        return INT_CONTINUE;
        
    tdsdump_log(TDS_DBG_FUNC, "_dblib_check_and_handle_interrupt %p [%p, %p]\n", dbproc, dbproc->chkintr, dbproc->hndlintr);
 
    if (dbproc->chkintr(dbproc)){
        switch (ret = dbproc->hndlintr(dbproc)) {
        case INT_EXIT:
            tdsdump_log(TDS_DBG_FUNC, "dbproc->hndlintr returned INT_EXIT, goodbye!\n");
            exit(1);
        case INT_CANCEL:
            tdsdump_log(TDS_DBG_FUNC, "dbproc->hndlintr returned INT_CANCEL\n");
            break;
        case INT_CONTINUE:
            tdsdump_log(TDS_DBG_FUNC, "dbproc->hndlintr returned INT_CONTINUE\n");
            break;
        default:
            tdsdump_log(TDS_DBG_FUNC, "dbproc->hndlintr returned an invalid value (%d), returning INT_CONTINUE\n", ret);
            ret = INT_CONTINUE;
            break;
        }
    }
    return ret;
}
 
 
void
_dblib_setTDS_version(TDSLOGIN * tds_login, DBINT version)
{
    switch (version) {
    case DBVERSION_42:
        tds_set_version(tds_login, 4, 2);
        break;
    case DBVERSION_46:
        tds_set_version(tds_login, 4, 6);
        break;
    case DBVERSION_100:
        tds_set_version(tds_login, 5, 0);
        break;
    }
}
 
void
_dblib_convert_err(DBPROCESS * dbproc, TDS_INT len)
{
    switch (len) {
    case TDS_CONVERT_NOAVAIL:
        dbperror(dbproc, SYBERDCN, 0);
        break;
    case TDS_CONVERT_SYNTAX:
        dbperror(dbproc, SYBECSYN, 0);
        break;
    case TDS_CONVERT_NOMEM:
        dbperror(dbproc, SYBEMEM, ENOMEM);
        break;
    case TDS_CONVERT_OVERFLOW:
        dbperror(dbproc, SYBECOFL, 0);
        break;
    default:
    case TDS_CONVERT_FAIL:
        dbperror(dbproc, SYBECINTERNAL, 0);
        break;
    }
}