/* * dlproc.c * * $Id: dlproc.c,v 1.14 2006/01/20 15:58:34 source Exp $ * * Load driver and resolve driver's function entry point * * The iODBC driver manager. * * Copyright (C) 1995 by Ke Jin <kejin@empress.com> * Copyright (C) 1996-2006 by OpenLink Software <iodbc@openlinksw.com> * All Rights Reserved. * * This software is released under the terms of either of the following * licenses: * * - GNU Library General Public License (see LICENSE.LGPL) * - The BSD License (see LICENSE.BSD). * * Note that the only valid version of the LGPL license as far as this * project is concerned is the original GNU Library General Public License * Version 2, dated June 1991. * * While not mandated by the BSD license, any patches you make to the * iODBC source code may be contributed back into the iODBC project * at your discretion. Contributions will benefit the Open Source and * Data Access community as a whole. Submissions may be made at: * * http://www.iodbc.org * * * GNU Library Generic Public License Version 2 * ============================================ * 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; only * Version 2 of the License dated June 1991. * * 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 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * * * The BSD License * =============== * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name of OpenLink Software Inc. nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL OPENLINK OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include <iodbc.h> #include <sql.h> #include <sqlext.h> #include <dlproc.h> #include <herr.h> #include <henv.h> #include <hdbc.h> #include <itrace.h> char *odbcapi_symtab[] = { "UNKNOWN FUNCTION" #define FUNCDEF(A, B, C) ,C #include "henv.ci" #undef FUNCDEF }; HPROC _iodbcdm_getproc (HDBC hdbc, int idx) { CONN (pdbc, hdbc); ENV_t *penv; HPROC *phproc; if (idx <= 0 || idx >= __LAST_API_FUNCTION__) return SQL_NULL_HPROC; penv = (ENV_t *) (pdbc->henv); if (penv == NULL) return SQL_NULL_HPROC; phproc = penv->dllproc_tab + idx; if (*phproc == SQL_NULL_HPROC) *phproc = _iodbcdm_dllproc (penv->hdll, odbcapi_symtab[idx]); return *phproc; } static dlproc_t *pRoot = NULL; HDLL _iodbcdm_dllopen (char *path) { dlproc_t *pDrv = NULL, *p; /* * Check if we have already loaded the driver */ for (p = pRoot; p; p = p->next) { if (STREQ (p->path, path)) { pDrv = p; break; } } /* * If already loaded, increase ref counter */ if (pDrv) { pDrv->refcount++; /* * If the driver was unloaded, load it again */ if (pDrv->dll == NULL) pDrv->dll = (HDLL) DLL_OPEN (path); return pDrv->dll; } /* * Initialize new structure */ if ((pDrv = calloc (1, sizeof (dlproc_t))) == NULL) return NULL; pDrv->refcount = 1; pDrv->path = STRDUP (path); pDrv->dll = (HDLL) DLL_OPEN (path); /* * Add to linked list */ pDrv->next = pRoot; pRoot = pDrv; return pDrv->dll; } HPROC _iodbcdm_dllproc (HDLL hdll, char *sym) { return (HPROC) DLL_PROC (hdll, sym); } int _iodbcdm_dllclose (HDLL hdll) { dlproc_t *pDrv = NULL, *p; /* * Find loaded driver */ for (p = pRoot; p; p = p->next) { if (p->dll == hdll) { pDrv = p; break; } } /* * Not found */ if (!pDrv) return -1; /* * Decrease reference counter */ pDrv->refcount--; /* * Check if it is possible to unload the driver safely * * NOTE: Some drivers set explicit on_exit hooks, which makes it * impossible for the driver manager to unload the driver * as this would crash the executable at exit. */ if (pDrv->refcount == 0 && pDrv->safe_unload) { DLL_CLOSE (pDrv->dll); pDrv->dll = NULL; } return 0; } char * _iodbcdm_dllerror () { return DLL_ERROR (); } /* * If driver manager determines this driver is safe, flag the driver can * be unloaded if not used. */ void _iodbcdm_safe_unload (HDLL hdll) { dlproc_t *pDrv = NULL, *p; /* * Find loaded driver */ for (p = pRoot; p; p = p->next) { if (p->dll == hdll) { pDrv = p; break; } } /* * Driver not found */ if (!pDrv) return; pDrv->safe_unload = 1; }