ladspa.c

   1 /* ladspa.c - helper functions related to LADSPA
   2  *   based on files from the LADSPA SDK
   3  * Copyright © 2013 Géraud Meyer <graud@gmx.com>
   4  *
   5  * This file is part of ng-jackspa.
   6  *
   7  * ng-jackspa is free software; you can redistribute it and/or modify it under
   8  * the terms of the GNU General Public License version 2 as published by the
   9  * Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with ng-jackspa.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 /* dlopen() wrapper.  When the filename is not an absolute path, search the
  21  * LADSPA_PATH.
  22  */
  23 static void *ladspa_dlopen(const char *file, int flag)
  24 {
  25         char *strbuf;
  26         const char *LADSPA_PATH, *start, *end;
  27         size_t filenlength;
  28         void *handle; /* returned handle */
  29
  30         filenlength = strlen(file);
  31         handle = NULL;
  32
  33         if (file[0] == '/') {
  34                 /* The filename is absolute */
  35                 handle = dlopen(file, flag);
  36                 if (handle != NULL)
  37                         return handle;
  38         }
  39         else if ((LADSPA_PATH = getenv("LADSPA_PATH")) ) {
  40                 /* Check along the LADSPA_PATH path to see if we can find the file
  41                  * there. We do NOT call dlopen() directly as this would find plugins
  42                  * on the LD_LIBRARY_PATH */
  43                 for (start = LADSPA_PATH; *start; start = *end == ':' ? ++end : end) {
  44                         for (end = start; *end != ':' && *end; end++);
  45
  46                         if (!(strbuf = malloc(filenlength + 2 + (end - start)))) {
  47                                 fputs("memory allocation error\n", stderr);
  48                                 continue;
  49                         }
  50                         strncpy(strbuf, start, end - start);
  51                         if (end > start && *(end - 1) != '/') {
  52                                 strbuf[end - start] = '/';
  53                                 strcpy(strbuf + 1 + (end - start), file);
  54                         }
  55                         else
  56                                 strcpy(strbuf, file);
  57
  58                         handle = dlopen(strbuf, flag);
  59
  60                         free(strbuf);
  61                         if (handle != NULL)
  62                                 return handle;
  63                 }
  64         }
  65
  66         /* As a last effort, try to add the suffix ".so" and recurse */
  67         if (filenlength <= 3 || strcmp(file + filenlength - 3, ".so")) {
  68                 if (!(strbuf = malloc(filenlength + 4)))
  69                         fputs("memory allocation error\n", stderr);
  70                 else {
  71                         strcpy(strbuf, file);
  72                         strcat(strbuf, ".so");
  73
  74                         handle = ladspa_dlopen(strbuf, flag);
  75
  76                         free(strbuf);
  77                         if (handle != NULL)
  78                                 return handle;
  79                 }
  80         }
  81
  82         /* If nothing has worked, then at least we can make sure we set the correct
  83          * error message - and this should correspond to a call to dlopen() with
  84          * the actual filename requested.
  85          * The dlopen() manual page does not specify whether the first or last
  86          * error message will be kept when multiple calls are made to dlopen().
  87          * We've covered the former case - now we can handle the latter by calling
  88          * dlopen() again here.
  89          */
  90         return dlopen(file, flag);
  91 }