src/os2/plugin.c

   1 /*****************************************************************************
   2  * plugin.c : Low-level dynamic library handling
   3  *****************************************************************************
   4  * Copyright (C) 2001-2007 VLC authors and VideoLAN
   5  * Copyright (C) 2012 KO Myung-Hun
   6  * $Id$
   7  *
   8  * Authors: Sam Hocevar <sam@zoy.org>
   9  *          Ethan C. Baldridge <BaldridgeE@cadmus.com>
  10  *          Hans-Peter Jansen <hpj@urpla.net>
  11  *          Gildas Bazin <gbazin@videolan.org>
  12  *          KO Myung-Hun <komh@chollian.net>
  13  *
  14  * This program is free software; you can redistribute it and/or modify it
  15  * under the terms of the GNU Lesser General Public License as published by
  16  * the Free Software Foundation; either version 2.1 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  22  * GNU Lesser General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Lesser General Public License
  25  * along with this program; if not, write to the Free Software Foundation,
  26  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  27  *****************************************************************************/
  28
  29 #ifdef HAVE_CONFIG_H
  30 # include "config.h"
  31 #endif
  32
  33 #include <string.h>
  34
  35 #include <vlc_common.h>
  36 #include <vlc_charset.h>
  37 #include "modules/modules.h"
  38
  39 #include <sys/types.h>
  40 #include <dlfcn.h>
  41
  42 /**
  43  * Load a dynamically linked library using a system dependent method.
  44  *
  45  * \param p_this vlc object
  46  * \param psz_file library file
  47  * \param p_handle the module handle returned
  48  * \return 0 on success as well as the module handle.
  49  */
  50 int module_Load( vlc_object_t *p_this, const char *psz_file,
  51                  module_handle_t *p_handle, bool lazy )
  52 {
  53     const int flags = lazy ? RTLD_LAZY : RTLD_NOW;
  54     char *path = ToLocaleDup( psz_file );
  55
  56     module_handle_t handle = dlopen( path, flags );
  57     if( handle == NULL )
  58     {
  59         msg_Warn( p_this, "cannot load module `%s' (%s)", path, dlerror() );
  60         free( path );
  61         return -1;
  62     }
  63     free( path );
  64     *p_handle = handle;
  65     return 0;
  66 }
  67
  68 /**
  69  * CloseModule: unload a dynamic library
  70  *
  71  * This function unloads a previously opened dynamically linked library
  72  * using a system dependent method. No return value is taken in consideration,
  73  * since some libraries sometimes refuse to close properly.
  74  * \param handle handle of the library
  75  * \return nothing
  76  */
  77 void module_Unload( module_handle_t handle )
  78 {
  79     dlclose( handle );
  80 }
  81
  82 /**
  83  * Looks up a symbol from a dynamically loaded library
  84  *
  85  * This function queries a loaded library for a symbol specified in a
  86  * string, and returns a pointer to it. We don't check for dlerror() or
  87  * similar functions, since we want a non-NULL symbol anyway.
  88  *
  89  * @param handle handle to the module
  90  * @param psz_function function name
  91  * @return NULL on error, or the address of the symbol
  92  */
  93 void *module_Lookup( module_handle_t handle, const char *psz_function )
  94 {
  95     char buf[strlen(psz_function) + 2];
  96     buf[0] = '_';
  97     strcpy(buf + 1, psz_function);
  98     return dlsym( handle, buf );
  99 }