mono/utils/mono-embed.c

   1 /*
   2  * mono-embed.c: Example code APIs to register a libraries using
   3  * mono_dl_fallback_register.  Real implementations should instead
   4  * use a binary search for implementing the dl_mapping_open and
   5  * dl_mapping_symbol methods here.
   6  *
   7  * Author:
   8  *    Mono Team (http://www.mono-project.com)
   9  *
  10  * Copyright 2001-2004 Ximian, Inc.
  11  * Copyright 2004-2010 Novell, Inc.
  12  *
  13  * Licensed under the MIT license. See LICENSE file in the project root for full license information.
  14  */
  15 #include "config.h"
  16 #include "mono/utils/mono-dl.h"
  17 #include "mono/utils/mono-embed.h"
  18
  19 #include <stdlib.h>
  20 #include <stdio.h>
  21 #include <ctype.h>
  22 #include <string.h>
  23 #include <glib.h>
  24
  25 static GHashTable *mono_dls;
  26
  27 static void *
  28 dl_mapping_open (const char *file, int flags, char **err, void *user_data)
  29 {
  30         MonoDlMapping *mappings;
  31
  32         if (mono_dls == NULL){
  33                 *err = g_strdup ("Library not registered");
  34                 return NULL;
  35         }
  36
  37         mappings = (MonoDlMapping *) g_hash_table_lookup (mono_dls, file);
  38         *err = g_strdup (mappings == NULL ? "File not registered" : "");
  39         return mappings;
  40 }
  41
  42 static void *
  43 dl_mapping_symbol (void *handle, const char *symbol, char **err, void *user_data)
  44 {
  45         MonoDlMapping *mappings = (MonoDlMapping *) handle;
  46
  47         for (;mappings->name; mappings++){
  48                 if (strcmp (symbol, mappings->name) == 0){
  49                         *err = g_strdup ("");
  50                         return mappings->addr;
  51                 }
  52         }
  53         *err = g_strdup ("Symbol not found");
  54         return NULL;
  55 }
  56
  57 /**
  58  * mono_dl_register_library:
  59 u * @name: Library name, this is the name used by the DllImport as the external library name
  60  * @mappings: the mappings to register for P/Invoke.
  61  *
  62  * The mappings registered using this function are used as fallbacks if the dynamic linker
  63  * fails, or if the platform doesn't have a dynamic linker.
  64  *
  65  * Mappings is a pointer to the first element of an array of
  66  * MonoDlMapping values.  The list must be terminated with both
  67  * the name and addr fields set to NULL.
  68  *
  69  * This is typically used like this:
  70  * MonoDlMapping sample_library_mappings [] = {
  71  *   { "CallMe", CallMe },
  72  *   { NULL, NULL }
  73  * };
  74  *
  75  * ...
  76  * main ()
  77  * {
  78  *    ...
  79  *    mono_dl_register_library ("sample", sample_library_mappings);
  80  *    ...
  81  * }
  82  *
  83  * Then the C# code can use this P/Invoke signature:
  84  *
  85  *      [DllImport ("sample")]
  86  *      extern static int CallMe (int f);
  87  */
  88 void
  89 mono_dl_register_library (const char *name, MonoDlMapping *mappings)
  90 {
  91         if (mono_dls == NULL){
  92                 mono_dls = g_hash_table_new (g_str_hash, g_str_equal);
  93                 mono_dl_fallback_register (dl_mapping_open, dl_mapping_symbol, NULL, NULL);
  94         }
  95
  96         g_hash_table_insert (mono_dls, g_strdup (name), mappings);
  97 }
  98