2004-05-28 Gonzalo Paniagua Javier <gonzalo@ximian.com>
[mono.git] / mono / metadata / assembly.c
index 6f9c6cc78b22b7a88057d3fa1fcafd81d29c92fc..d5b4fdcd8d6b19e78c1aad09fb5f1364cce91e89 100644 (file)
 #include "image.h"
 #include "cil-coff.h"
 #include "rawbuffer.h"
+#ifdef WITH_BUNDLE
+#include "mono-bundle.h"
+#endif
+#include <mono/metadata/loader.h>
+#include <mono/metadata/tabledefs.h>
+#include <mono/io-layer/io-layer.h>
+#include <mono/utils/mono-uri.h>
+#include <mono/metadata/mono-config.h>
+#include <mono/utils/mono-digest.h>
+#ifdef PLATFORM_WIN32
+#include <mono/os/util.h>
+#endif
 
 /* the default search path is just MONO_ASSEMBLIES */
 static const char*
@@ -28,72 +40,148 @@ default_path [] = {
 };
 
 static char **assemblies_path = NULL;
-static int env_checked = 0;
+
+/*
+ * keeps track of loaded assemblies
+ */
+static GList *loaded_assemblies = NULL;
+static MonoAssembly *corlib;
+
+/* This protects loaded_assemblies and image->references */
+static CRITICAL_SECTION assemblies_mutex;
+
+/* A hastable of thread->assembly list mappings */
+static GHashTable *assemblies_loading;
+
+static char **extra_gac_paths = NULL;
+
+static gchar*
+encode_public_tok (const guchar *token, gint32 len)
+{
+       static gchar allowed [] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
+       gchar *res;
+       int i;
+
+       res = g_malloc (len * 2 + 1);
+       for (i = 0; i < len; i++) {
+               res [i * 2] = allowed [token [i] >> 4];
+               res [i * 2 + 1] = allowed [token [i] & 0xF];
+       }
+       res [len * 2] = 0;
+       return res;
+}
 
 static void
-check_env (void) {
+check_path_env (void) {
        const char *path;
        char **splitted;
        
-       if (env_checked)
-               return;
-       env_checked = 1;
-
-       path = getenv ("MONO_PATH");
+       path = g_getenv ("MONO_PATH");
        if (!path)
                return;
+
        splitted = g_strsplit (path, G_SEARCHPATH_SEPARATOR_S, 1000);
        if (assemblies_path)
                g_strfreev (assemblies_path);
        assemblies_path = splitted;
+       if (g_getenv ("MONO_DEBUG") == NULL)
+               return;
+
+       while (*splitted) {
+               if (**splitted && !g_file_test (*splitted, G_FILE_TEST_IS_DIR))
+                       g_warning ("'%s' in MONO_PATH doesn't exist or has wrong permissions.", *splitted);
+
+               splitted++;
+       }
 }
 
-/*
- * keeps track of loaded assemblies
- */
-static GList *loaded_assemblies = NULL;
-static MonoAssembly *corlib;
+static void
+check_extra_gac_path_env (void) {
+       const char *path;
+       char **splitted;
+       
+       path = g_getenv ("MONO_GAC_PATH");
+       if (!path)
+               return;
 
+       splitted = g_strsplit (path, G_SEARCHPATH_SEPARATOR_S, 1000);
+       if (extra_gac_paths)
+               g_strfreev (extra_gac_paths);
+       extra_gac_paths = splitted;
+       if (g_getenv ("MONO_DEBUG") == NULL)
+               return;
+
+       while (*splitted) {
+               if (**splitted && !g_file_test (*splitted, G_FILE_TEST_IS_DIR))
+                       g_warning ("'%s' in MONO_GAC_PATH doesn't exist or has wrong permissions.", *splitted);
+
+               splitted++;
+       }
+}
+
+static gboolean
+mono_assembly_names_equal (MonoAssemblyName *l, MonoAssemblyName *r)
+{
+       if (!l->name || !r->name)
+               return FALSE;
+
+       if (strcmp (l->name, r->name))
+               return FALSE;
+
+        /*
+         * simply compare names until some other issues are resolved
+         * (version info not getting set correctly for custom
+         * attributes).
+         */
+        /*
+       if (l->major != r->major || l->minor != r->minor ||
+                       l->build != r->build || l->revision != r->revision)
+               return FALSE;
+
+       if (!l->public_tok_value && !r->public_tok_value)
+               return TRUE;
+
+       if ((l->public_tok_value && !r->public_tok_value) || (!l->public_tok_value && r->public_tok_value))
+               return FALSE;
+
+       if (strcmp (l->public_tok_value, r->public_tok_value))
+               return FALSE;
+        */
+       return TRUE;
+}
+
+/* assemblies_mutex must be held by the caller */
 static MonoAssembly*
 search_loaded (MonoAssemblyName* aname)
 {
        GList *tmp;
        MonoAssembly *ass;
+       GList *loading;
        
        for (tmp = loaded_assemblies; tmp; tmp = tmp->next) {
                ass = tmp->data;
-               /* we just compare the name, but later we'll do all the checks */
                /* g_print ("compare %s %s\n", aname->name, ass->aname.name); */
-               if (strcmp (aname->name, ass->aname.name))
+               if (!mono_assembly_names_equal (aname, &ass->aname))
                        continue;
                /* g_print ("success\n"); */
+
                return ass;
        }
-       return NULL;
-}
 
-/**
- * g_concat_dir_and_file:
- * @dir:  directory name
- * @file: filename.
- *
- * returns a new allocated string that is the concatenation of dir and file,
- * takes care of the exact details for concatenating them.
- */
-static char *
-g_concat_dir_and_file (const char *dir, const char *file)
-{
-       g_return_val_if_fail (dir != NULL, NULL);
-       g_return_val_if_fail (file != NULL, NULL);
-
-        /*
-        * If the directory name doesn't have a / on the end, we need
-        * to add one so we get a proper path to the file
+       /*
+        * The assembly might be under load by this thread. In this case, it is
+        * safe to return an incomplete instance to prevent loops.
         */
-       if (dir [strlen(dir) - 1] != G_DIR_SEPARATOR)
-               return g_strconcat (dir, G_DIR_SEPARATOR_S, file, NULL);
-       else
-               return g_strconcat (dir, file, NULL);
+       loading = g_hash_table_lookup (assemblies_loading, GetCurrentThread ());
+       for (tmp = loading; tmp; tmp = tmp->next) {
+               ass = tmp->data;
+               if (!mono_assembly_names_equal (aname, &ass->aname))
+                       continue;
+
+               return ass;
+       }
+
+       return NULL;
 }
 
 static MonoAssembly *
@@ -104,7 +192,7 @@ load_in_path (const char *basename, const char** search_path, MonoImageOpenStatu
        MonoAssembly *result;
 
        for (i = 0; search_path [i]; ++i) {
-               fullpath = g_concat_dir_and_file (search_path [i], basename);
+               fullpath = g_build_filename (search_path [i], basename, NULL);
                result = mono_assembly_open (fullpath, status);
                g_free (fullpath);
                if (result)
@@ -128,22 +216,107 @@ mono_assembly_setrootdir (const char *root_dir)
        /*
         * Override the MONO_ASSEMBLIES directory configured at compile time.
         */
+       /* Leak if called more than once */
        default_path [0] = g_strdup (root_dir);
 }
 
-static void
-load_references (MonoImage *image, MonoImageOpenStatus *status) {
+G_CONST_RETURN gchar *
+mono_assembly_getrootdir (void)
+{
+       return default_path [0];
+}
+
+/**
+ * mono_assemblies_init:
+ *
+ *  Initialize global variables used by this module.
+ */
+void
+mono_assemblies_init (void)
+{
+#ifdef PLATFORM_WIN32
+       mono_set_rootdir ();
+#endif
+
+       check_path_env ();
+       check_extra_gac_path_env ();
+
+       InitializeCriticalSection (&assemblies_mutex);
+
+       assemblies_loading = g_hash_table_new (NULL, NULL);
+}
+
+gboolean
+mono_assembly_fill_assembly_name (MonoImage *image, MonoAssemblyName *aname)
+{
+       MonoTableInfo *t = &image->tables [MONO_TABLE_ASSEMBLY];
+       guint32 cols [MONO_ASSEMBLY_SIZE];
+
+       if (!t->rows)
+               return FALSE;
+
+       mono_metadata_decode_row (t, 0, cols, MONO_ASSEMBLY_SIZE);
+
+       aname->hash_len = 0;
+       aname->hash_value = NULL;
+       aname->name = mono_metadata_string_heap (image, cols [MONO_ASSEMBLY_NAME]);
+       aname->culture = mono_metadata_string_heap (image, cols [MONO_ASSEMBLY_CULTURE]);
+       aname->flags = cols [MONO_ASSEMBLY_FLAGS];
+       aname->major = cols [MONO_ASSEMBLY_MAJOR_VERSION];
+       aname->minor = cols [MONO_ASSEMBLY_MINOR_VERSION];
+       aname->build = cols [MONO_ASSEMBLY_BUILD_NUMBER];
+       aname->revision = cols [MONO_ASSEMBLY_REV_NUMBER];
+       aname->hash_alg = cols [MONO_ASSEMBLY_HASH_ALG];
+       if (cols [MONO_ASSEMBLY_PUBLIC_KEY])
+               aname->public_key = mono_metadata_blob_heap (image, cols [MONO_ASSEMBLY_PUBLIC_KEY]);
+       else
+               aname->public_key = 0;
+
+       return TRUE;
+}
+
+static gchar*
+assemblyref_public_tok (MonoImage *image, guint32 key_index, guint32 flags)
+{
+       const gchar *public_tok;
+       int len;
+
+       public_tok = mono_metadata_blob_heap (image, key_index);
+       len = mono_metadata_decode_blob_size (public_tok, &public_tok);
+
+       if (flags & ASSEMBLYREF_FULL_PUBLIC_KEY_FLAG) {
+               gchar token [8];
+               mono_digest_get_public_token (token, public_tok, len);
+               return encode_public_tok (token, 8);
+       }
+
+       return encode_public_tok (public_tok, len);
+}
+
+void
+mono_assembly_load_references (MonoImage *image, MonoImageOpenStatus *status)
+{
        MonoTableInfo *t;
        guint32 cols [MONO_ASSEMBLYREF_SIZE];
        const char *hash;
        int i;
+       MonoAssembly **references = NULL;
 
-       if (image->references)
+       *status = MONO_IMAGE_OK;
+       
+       /*
+        * image->references is shared between threads, so we need to access
+        * it inside a critical section.
+        */
+       EnterCriticalSection (&assemblies_mutex);
+       references = image->references;
+       LeaveCriticalSection (&assemblies_mutex);
+       if (references)
                return;
 
        t = &image->tables [MONO_TABLE_ASSEMBLYREF];
 
-       image->references = g_new0 (MonoAssembly *, t->rows + 1);
+       references = g_new0 (MonoAssembly *, t->rows + 1);
 
        /*
         * Load any assemblies this image references
@@ -164,23 +337,83 @@ load_references (MonoImage *image, MonoImageOpenStatus *status) {
                aname.build = cols [MONO_ASSEMBLYREF_BUILD_NUMBER];
                aname.revision = cols [MONO_ASSEMBLYREF_REV_NUMBER];
 
-               image->references [i] = mono_assembly_load (&aname, image->assembly->basedir, status);
+               if (cols [MONO_ASSEMBLYREF_PUBLIC_KEY]) {
+                       aname.public_tok_value = assemblyref_public_tok (image,
+                                       cols [MONO_ASSEMBLYREF_PUBLIC_KEY], aname.flags);
+               } else {
+                       aname.public_tok_value = NULL;
+               } 
+
+               references [i] = mono_assembly_load (&aname, image->assembly->basedir, status);
 
-               if (image->references [i] == NULL){
+               if (references [i] == NULL){
                        int j;
+
+                       /*
+                       ** Temporary work around: any System.* which are 3300 build, will get
+                       ** remapped, this is to keep old applications running that might have
+                       ** been linked against our 5000 API, before we were strongnamed, and
+                       ** hence were labeled as 3300 builds by reflection.c
+                       */
+                       if (aname.build == 3300 && strncmp (aname.name, "System", 6) == 0){
+                               aname.build = 5000;
+                               
+                               references [i] = mono_assembly_load (&aname, image->assembly->basedir, status);
+                       }
+                       if (references [i] != NULL){
+                               if (g_getenv ("MONO_SILENT_WARNING") == NULL)
+                                       g_printerr ("Compat mode: the request from %s to load %s was remapped (http://www.go-mono.com/remap.html)\n",
+                                                image->name, aname.name);
+                               
+                       } else {
                        
-                       for (j = 0; j < i; j++)
-                               mono_assembly_close (image->references [j]);
-                       g_free (image->references);
-                       image->references = NULL;
-
-                       g_warning ("Could not find assembly %s", aname.name);
-                       *status = MONO_IMAGE_MISSING_ASSEMBLYREF;
-                       return;
+                               for (j = 0; j < i; j++)
+                                       mono_assembly_close (references [j]);
+                               g_free (references);
+                               
+                               g_warning ("Could not find assembly %s, references from %s (assemblyref_index=%d)\n"
+                                          "     Major/Minor: %d,%d\n"
+                                          "     Build:       %d,%d\n"
+                                          "     Token:       %s\n",
+                                          aname.name, image->name, i,
+                                          aname.major, aname.minor, aname.build, aname.revision,
+                                          aname.public_tok_value);
+                               *status = MONO_IMAGE_MISSING_ASSEMBLYREF;
+                               return;
+                       }
+               }
+
+               /* 
+                * This check is disabled since lots of people seem to have an older
+                * corlib which triggers this.
+                */
+               /* 
+               if (image->references [i]->image == image)
+                       g_error ("Error: Assembly %s references itself", image->name);
+               */
+       }
+       references [i] = NULL;
+
+       /* resolve assembly references for modules */
+       t = &image->tables [MONO_TABLE_MODULEREF];
+       for (i = 0; i < t->rows; i++){
+               if (image->modules [i]) {
+                       image->modules [i]->assembly = image->assembly;
+                       mono_assembly_load_references (image->modules [i], status);
                }
        }
-       image->references [i] = NULL;
 
+       EnterCriticalSection (&assemblies_mutex);
+       if (!image->references)
+               image->references = references;
+       LeaveCriticalSection (&assemblies_mutex);
+
+       if (image->references != references) {
+               /* Somebody loaded it before us */
+               for (i = 0; i < t->rows; i++)
+                       mono_assembly_close (references [i]);
+               g_free (references);
+       }
 }
 
 typedef struct AssemblyLoadHook AssemblyLoadHook;
@@ -192,8 +425,8 @@ struct AssemblyLoadHook {
 
 AssemblyLoadHook *assembly_load_hook = NULL;
 
-static void
-invoke_assembly_hook (MonoAssembly *ass)
+void
+mono_assembly_invoke_load_hook (MonoAssembly *ass)
 {
        AssemblyLoadHook *hook;
 
@@ -216,6 +449,44 @@ mono_install_assembly_load_hook (MonoAssemblyLoadFunc func, gpointer user_data)
        assembly_load_hook = hook;
 }
 
+typedef struct AssemblyPreLoadHook AssemblyPreLoadHook;
+struct AssemblyPreLoadHook {
+       AssemblyPreLoadHook *next;
+       MonoAssemblyPreLoadFunc func;
+       gpointer user_data;
+};
+
+AssemblyPreLoadHook *assembly_preload_hook = NULL;
+
+static MonoAssembly *
+invoke_assembly_preload_hook (MonoAssemblyName *aname, gchar **assemblies_path)
+{
+       AssemblyPreLoadHook *hook;
+       MonoAssembly *assembly;
+
+       for (hook = assembly_preload_hook; hook; hook = hook->next) {
+               assembly = hook->func (aname, assemblies_path, hook->user_data);
+               if (assembly != NULL)
+                       return assembly;
+       }
+
+       return NULL;
+}
+
+void
+mono_install_assembly_preload_hook (MonoAssemblyPreLoadFunc func, gpointer user_data)
+{
+       AssemblyPreLoadHook *hook;
+       
+       g_return_if_fail (func != NULL);
+
+       hook = g_new0 (AssemblyPreLoadHook, 1);
+       hook->func = func;
+       hook->user_data = user_data;
+       hook->next = assembly_preload_hook;
+       assembly_preload_hook = hook;
+}
+
 static gchar *
 absolute_dir (const gchar *filename)
 {
@@ -223,7 +494,7 @@ absolute_dir (const gchar *filename)
        gchar *mixed;
        gchar **parts;
        gchar *part;
-       GSList *list, *tmp;
+       GList *list, *tmp;
        GString *result;
        gchar *res;
        gint i;
@@ -244,14 +515,14 @@ absolute_dir (const gchar *filename)
 
                if (!strcmp (part, "..")) {
                        if (list && list->next) /* Don't remove root */
-                               list = g_slist_delete_link (list, list);
+                               list = g_list_delete_link (list, list);
                } else {
-                       list = g_slist_prepend (list, part);
+                       list = g_list_prepend (list, part);
                }
        }
 
        result = g_string_new ("");
-       list = g_slist_reverse (list);
+       list = g_list_reverse (list);
 
        /* Ignores last data pointer, which should be the filename */
        for (tmp = list; tmp && tmp->next != NULL; tmp = tmp->next)
@@ -261,7 +532,7 @@ absolute_dir (const gchar *filename)
        
        res = result->str;
        g_string_free (result, FALSE);
-       g_slist_free (list);
+       g_list_free (list);
        g_strfreev (parts);
        if (*res == '\0') {
                g_free (res);
@@ -271,6 +542,53 @@ absolute_dir (const gchar *filename)
        return res;
 }
 
+static MonoImage*
+do_mono_assembly_open (const char *filename, MonoImageOpenStatus *status)
+{
+       MonoImage *image = NULL;
+#ifdef WITH_BUNDLE
+       int i;
+       char *name = g_path_get_basename (filename);
+       char *dot = strrchr (name, '.');
+       GList *tmp;
+       MonoAssembly *ass;
+       
+       if (dot)
+               *dot = 0;
+       /* we do a very simple search for bundled assemblies: it's not a general 
+        * purpose assembly loading mechanism.
+        */
+       EnterCriticalSection (&assemblies_mutex);
+       for (tmp = loaded_assemblies; tmp; tmp = tmp->next) {
+               ass = tmp->data;
+               if (!ass->aname.name)
+                       continue;
+               if (strcmp (name, ass->aname.name))
+                       continue;
+               image = ass->image;
+               break;
+       }
+
+       for (i = 0; !image && bundled_assemblies [i]; ++i) {
+               if (strcmp (bundled_assemblies [i]->name, name) == 0) {
+                       image = mono_image_open_from_data ((char*)bundled_assemblies [i]->data, bundled_assemblies [i]->size, FALSE, status);
+                       break;
+               }
+       }
+       LeaveCriticalSection (&assemblies_mutex);
+       g_free (name);
+       if (image) {
+               mono_image_addref (image);
+               return image;
+       }
+#endif
+       EnterCriticalSection (&assemblies_mutex);
+       image = mono_image_open (filename, status);
+       LeaveCriticalSection (&assemblies_mutex);
+       
+       return image;
+}
+
 /**
  * mono_assembly_open:
  * @filename: Opens the assembly pointed out by this name
@@ -285,13 +603,10 @@ absolute_dir (const gchar *filename)
 MonoAssembly *
 mono_assembly_open (const char *filename, MonoImageOpenStatus *status)
 {
-       MonoAssembly *ass, *ass2;
        MonoImage *image;
-       MonoTableInfo *t;
-       guint32 cols [MONO_ASSEMBLY_SIZE];
-       int i;
-       char *base_dir, *aot_name;
+       MonoAssembly *ass;
        MonoImageOpenStatus def_status;
+       gchar *fname;
        
        g_return_val_if_fail (filename != NULL, NULL);
 
@@ -299,18 +614,67 @@ mono_assembly_open (const char *filename, MonoImageOpenStatus *status)
                status = &def_status;
        *status = MONO_IMAGE_OK;
 
-       /* g_print ("file loading %s\n", filename); */
-       image = mono_image_open (filename, status);
+       if (strncmp (filename, "file://", 7) == 0) {
+               GError *error = NULL;
+               gchar *uri = (gchar *) filename;
+               gchar *tmpuri;
+
+               /*
+                * MS allows file://c:/... and fails on file://localhost/c:/... 
+                * They also throw an IndexOutOfRangeException if "file://"
+                */
+               if (uri [7] != '/')
+                       uri = g_strdup_printf ("file:///%s", uri + 7);
+       
+               tmpuri = uri;
+               uri = mono_escape_uri_string (tmpuri);
+               fname = g_filename_from_uri (uri, NULL, &error);
+               g_free (uri);
+
+               if (tmpuri != filename)
+                       g_free (tmpuri);
+
+               if (error != NULL) {
+                       g_warning ("%s\n", error->message);
+                       g_error_free (error);
+                       fname = g_strdup (filename);
+               }
+       } else {
+               fname = g_strdup (filename);
+       }
+
+       /* g_print ("file loading %s\n", fname); */
+       image = do_mono_assembly_open (fname, status);
 
        if (!image){
                *status = MONO_IMAGE_ERROR_ERRNO;
+               g_free (fname);
                return NULL;
        }
 
+       ass = mono_assembly_load_from (image, fname, status);
+
+       mono_config_for_assembly (ass->image);
+
+       g_free (fname);
+
+       return ass;
+}
+
+MonoAssembly *
+mono_assembly_load_from (MonoImage *image, const char*fname, 
+                        MonoImageOpenStatus *status)
+{
+       MonoAssembly *ass, *ass2;
+       char *base_dir;
+       GList *loading;
+
 #if defined (PLATFORM_WIN32)
        {
                gchar *tmp_fn;
-               tmp_fn = g_strdup (filename);
+               int i;
+
+               tmp_fn = g_strdup (fname);
                for (i = strlen (tmp_fn) - 1; i >= 0; i--) {
                        if (tmp_fn [i] == '/')
                                tmp_fn [i] = '\\';
@@ -320,9 +684,17 @@ mono_assembly_open (const char *filename, MonoImageOpenStatus *status)
                g_free (tmp_fn);
        }
 #else
-       base_dir = absolute_dir (filename);
+       base_dir = absolute_dir (fname);
 #endif
 
+       /*
+        * To avoid deadlocks and scalability problems, we load assemblies outside
+        * the assembly lock. This means that multiple threads might try to load
+        * the same assembly at the same time. The first one to load it completely
+        * "wins", the other threads free their copy and use the one loaded by
+        * the winning thread.
+        */
+
        /*
         * Create assembly struct, and enter it into the assembly cache
         */
@@ -330,108 +702,230 @@ mono_assembly_open (const char *filename, MonoImageOpenStatus *status)
        ass->basedir = base_dir;
        ass->image = image;
 
-       /* load aot compiled module */
-       aot_name = g_strdup_printf ("%s.so", filename);
-       ass->aot_module = g_module_open (aot_name, G_MODULE_BIND_LAZY);
-       g_free (aot_name);
-
-       if (ass->aot_module) {
-               char *saved_guid = NULL;
-               g_module_symbol (ass->aot_module, "mono_assembly_guid", &saved_guid);
-
-               if (!saved_guid || strcmp (image->guid, saved_guid)) {
-                       g_module_close (ass->aot_module);
-                       ass->aot_module = NULL;
-               }
-       }
-
-       t = &image->tables [MONO_TABLE_ASSEMBLY];
-       if (t->rows) {
-               mono_metadata_decode_row (t, 0, cols, MONO_ASSEMBLY_SIZE);
-               
-               ass->aname.hash_len = 0;
-               ass->aname.hash_value = NULL;
-               ass->aname.name = mono_metadata_string_heap (image, cols [MONO_ASSEMBLY_NAME]);
-               ass->aname.culture = mono_metadata_string_heap (image, cols [MONO_ASSEMBLY_CULTURE]);
-               ass->aname.flags = cols [MONO_ASSEMBLY_FLAGS];
-               ass->aname.major = cols [MONO_ASSEMBLY_MAJOR_VERSION];
-               ass->aname.minor = cols [MONO_ASSEMBLY_MINOR_VERSION];
-               ass->aname.build = cols [MONO_ASSEMBLY_BUILD_NUMBER];
-               ass->aname.revision = cols [MONO_ASSEMBLY_REV_NUMBER];
+       mono_assembly_fill_assembly_name (image, &ass->aname);
 
+       /* 
+        * Atomically search the loaded list and add ourselves to it if necessary.
+        */
+       EnterCriticalSection (&assemblies_mutex);
+       if (ass->aname.name)
                /* avoid loading the same assembly twice for now... */
                if ((ass2 = search_loaded (&ass->aname))) {
                        g_free (ass);
                        g_free (base_dir);
+                       mono_image_close (image);
                        *status = MONO_IMAGE_OK;
+                       LeaveCriticalSection (&assemblies_mutex);
                        return ass2;
                }
-       }
+       loading = g_hash_table_lookup (assemblies_loading, GetCurrentThread ());
+       loading = g_list_prepend (loading, ass);
+       g_hash_table_insert (assemblies_loading, GetCurrentThread (), loading);
+       LeaveCriticalSection (&assemblies_mutex);
 
        image->assembly = ass;
 
-       /* register right away to prevent loops */
-       loaded_assemblies = g_list_prepend (loaded_assemblies, ass);
+       /*
+        * We load referenced assemblies outside the lock to prevent deadlocks
+        * with regards to preload hooks.
+        */
+       mono_assembly_load_references (image, status);
 
-       load_references (image, status);
+       EnterCriticalSection (&assemblies_mutex);
+
+       loading = g_hash_table_lookup (assemblies_loading, GetCurrentThread ());
+       loading = g_list_remove (loading, ass);
+       if (loading == NULL)
+               /* Prevent memory leaks */
+               g_hash_table_remove (assemblies_loading, GetCurrentThread ());
+       else
+               g_hash_table_insert (assemblies_loading, GetCurrentThread (), loading);
        if (*status != MONO_IMAGE_OK) {
+               LeaveCriticalSection (&assemblies_mutex);
                mono_assembly_close (ass);
                return NULL;
        }
-       
-       t = &image->tables [MONO_TABLE_MODULEREF];
-       ass->modules = g_new0 (MonoImage *, t->rows);
-       for (i = 0; i < t->rows; i++){
-               char *module_ref;
-               const char *name;
-               guint32 cols [MONO_MODULEREF_SIZE];
-
-               mono_metadata_decode_row (t, i, cols, MONO_MODULEREF_SIZE);
-               name = mono_metadata_string_heap (image, cols [MONO_MODULEREF_NAME]);
-               module_ref = g_concat_dir_and_file (base_dir, name);
-               ass->modules [i] = mono_image_open (module_ref, status);
-               if (ass->modules [i]) {
-                       ass->modules [i]->assembly = ass;
-                       load_references (ass->modules [i], status);
+
+       if (ass->aname.name) {
+               ass2 = search_loaded (&ass->aname);
+               if (ass2) {
+                       /* Somebody else has loaded the assembly before us */
+                       LeaveCriticalSection (&assemblies_mutex);
+                       mono_assembly_close (ass);
+                       return ass2;
                }
-               /* 
-                * FIXME: what do we do here? it could be a native dll...
-                * We should probably do lazy-loading of modules.
-                */
-               *status = MONO_IMAGE_OK;
-               g_free (module_ref);
        }
 
-       invoke_assembly_hook (ass);
+       loaded_assemblies = g_list_prepend (loaded_assemblies, ass);
+       LeaveCriticalSection (&assemblies_mutex);
+
+       mono_assembly_invoke_load_hook (ass);
 
        return ass;
 }
 
+static MonoAssembly*
+probe_for_partial_name (const char *basepath, const char *fullname, MonoImageOpenStatus *status)
+{
+       MonoAssembly *res = NULL;
+       gchar *fullpath;
+       GDir *dirhandle;
+       const char* direntry;
+
+       dirhandle = g_dir_open (basepath, 0, NULL);
+       if (!dirhandle)
+               return NULL;
+
+       while ((direntry = g_dir_read_name (dirhandle))) {
+               fullpath = g_build_path (G_DIR_SEPARATOR_S, basepath, direntry, fullname, NULL);
+               res = mono_assembly_open (fullpath, status);
+               g_free (fullpath);
+               if (res)
+                       break;
+       }
+       g_dir_close (dirhandle);
+
+       return res;
+}
+
+MonoAssembly*
+mono_assembly_load_with_partial_name (const char *name, MonoImageOpenStatus *status)
+{
+       MonoAssembly *res;
+       MonoAssemblyName aname;
+       gchar *fullname, *gacpath;
+       gchar **paths;
+
+       memset (&aname, 0, sizeof (MonoAssemblyName));
+       aname.name = name;
+
+       res = mono_assembly_loaded (&aname);
+
+       if (res)
+               return res;
+
+       fullname = g_strdup_printf ("%s.dll", name);
+
+       if (extra_gac_paths) {
+               paths = extra_gac_paths;
+               while (!res && *paths) {
+                       gacpath = g_build_path (G_DIR_SEPARATOR_S, *paths, "gac", name, NULL);
+                       res = probe_for_partial_name (gacpath, fullname, status);
+                       g_free (gacpath);
+                       paths++;
+               }
+       }
+
+       if (res) {
+               res->in_gac = TRUE;
+               g_free (fullname);
+               return res;
+               
+       }
+
+       gacpath = g_build_path (G_DIR_SEPARATOR_S, mono_assembly_getrootdir (), "mono", "gac", name, NULL);
+       res = probe_for_partial_name (gacpath, fullname, status);
+       g_free (gacpath);
+
+       if (res)
+               res->in_gac = TRUE;
+
+       g_free (fullname);
+
+       return res;
+}
+
+/**
+ * mono_assembly_load_from_gac
+ *
+ * @aname: The assembly name object
+ */
+static MonoAssembly*
+mono_assembly_load_from_gac (MonoAssemblyName *aname,  gchar *filename, MonoImageOpenStatus *status)
+{
+       MonoAssembly *result = NULL;
+       gchar *name, *version, *fullpath, *subpath;
+       gint32 len;
+       gchar **paths;
+
+       if (!aname->public_tok_value) {
+               return NULL;
+       }
+
+       if (strstr (aname->name, ".dll")) {
+               len = strlen (filename) - 4;
+               name = g_malloc (len);
+               strncpy (name, aname->name, len);
+       } else {
+               name = g_strdup (aname->name);
+       }
+
+       version = g_strdup_printf ("%d.%d.%d.%d_%s_%s", aname->major,
+                       aname->minor, aname->build, aname->revision,
+                       aname->culture == NULL ? "" : aname->culture,
+                       aname->public_tok_value);
+       
+       subpath = g_build_path (G_DIR_SEPARATOR_S, name, version, filename, NULL);
+       g_free (name);
+       g_free (version);
+
+       if (extra_gac_paths) {
+               paths = extra_gac_paths;
+               while (!result && *paths) {
+                       fullpath = g_build_path (G_DIR_SEPARATOR_S, *paths, "gac", subpath, NULL);
+                       result = mono_assembly_open (fullpath, status);
+                       g_free (fullpath);
+                       paths++;
+               }
+       }
+
+       if (result) {
+               result->in_gac = TRUE;
+               g_free (subpath);
+               return result;
+       }
+
+       fullpath = g_build_path (G_DIR_SEPARATOR_S, mono_assembly_getrootdir (),
+                       "mono", "gac", subpath, NULL);
+       result = mono_assembly_open (fullpath, status);
+       g_free (fullpath);
+
+       if (result)
+               result->in_gac = TRUE;
+       
+       g_free (subpath);
+
+       return result;
+}
+
+       
 MonoAssembly*
 mono_assembly_load (MonoAssemblyName *aname, const char *basedir, MonoImageOpenStatus *status)
 {
        MonoAssembly *result;
        char *fullpath, *filename;
 
-       check_env ();
-
+       result = invoke_assembly_preload_hook (aname, assemblies_path);
+       if (result)
+               return result;
        /* g_print ("loading %s\n", aname->name); */
        /* special case corlib */
-       if ((strcmp (aname->name, "mscorlib") == 0) || (strcmp (aname->name, "corlib") == 0)) {
+       if (strcmp (aname->name, "mscorlib") == 0) {
                if (corlib) {
                        /* g_print ("corlib already loaded\n"); */
                        return corlib;
                }
                /* g_print ("corlib load\n"); */
                if (assemblies_path) {
-                       corlib = load_in_path (CORLIB_NAME, (const char**)assemblies_path, status);
+                       corlib = load_in_path ("mscorlib.dll", (const char**)assemblies_path, status);
                        if (corlib)
                                return corlib;
                }
-               corlib = load_in_path (CORLIB_NAME, default_path, status);
+               corlib = load_in_path ("mscorlib.dll", default_path, status);
                return corlib;
        }
        result = search_loaded (aname);
+
        if (result)
                return result;
        /* g_print ("%s not found in cache\n", aname->name); */
@@ -439,11 +933,19 @@ mono_assembly_load (MonoAssemblyName *aname, const char *basedir, MonoImageOpenS
                filename = g_strdup (aname->name);
        else
                filename = g_strconcat (aname->name, ".dll", NULL);
+
+       result = mono_assembly_load_from_gac (aname, filename, status);
+       if (result) {
+               g_free (filename);
+               return result;
+       }
+
        if (basedir) {
-               fullpath = g_concat_dir_and_file (basedir, filename);
+               fullpath = g_build_filename (basedir, filename, NULL);
                result = mono_assembly_open (fullpath, status);
                g_free (fullpath);
                if (result) {
+                       result->in_gac = FALSE;
                        g_free (filename);
                        return result;
                }
@@ -451,15 +953,31 @@ mono_assembly_load (MonoAssemblyName *aname, const char *basedir, MonoImageOpenS
        if (assemblies_path) {
                result = load_in_path (filename, (const char**)assemblies_path, status);
                if (result) {
+                       result->in_gac = FALSE;
                        g_free (filename);
                        return result;
                }
        }
        result = load_in_path (filename, default_path, status);
+       
+       if (result)
+               result->in_gac = FALSE;
        g_free (filename);
        return result;
 }
 
+MonoAssembly*
+mono_assembly_loaded (MonoAssemblyName *aname)
+{
+       MonoAssembly *res;
+
+       EnterCriticalSection (&assemblies_mutex);
+       res = search_loaded (aname);
+       LeaveCriticalSection (&assemblies_mutex);
+
+       return res;
+}
+
 void
 mono_assembly_close (MonoAssembly *assembly)
 {
@@ -468,29 +986,55 @@ mono_assembly_close (MonoAssembly *assembly)
        
        g_return_if_fail (assembly != NULL);
 
-       if (--assembly->ref_count != 0)
+       EnterCriticalSection (&assemblies_mutex);
+       if (--assembly->ref_count != 0) {
+               LeaveCriticalSection (&assemblies_mutex);
                return;
-       
+       }
        loaded_assemblies = g_list_remove (loaded_assemblies, assembly);
+       LeaveCriticalSection (&assemblies_mutex);
        image = assembly->image;
        if (image->references) {
                for (i = 0; image->references [i] != NULL; i++)
                        mono_image_close (image->references [i]->image);
                g_free (image->references);
        }
-            
+
        mono_image_close (assembly->image);
 
        g_free (assembly->basedir);
        g_free (assembly);
 }
 
+MonoImage*
+mono_assembly_load_module (MonoAssembly *assembly, guint32 idx)
+{
+       MonoImageOpenStatus status;
+       MonoImage *module;
+
+       module = mono_image_load_file_for_image (assembly->image, idx);
+       if (module)
+               mono_assembly_load_references (module, &status);
+
+       return module;
+}
+
 void
 mono_assembly_foreach (GFunc func, gpointer user_data)
 {
-       /* In the future this can do locking of loaded_assemblies */
+       GList *copy;
+
+       /*
+     * We make a copy of the list to avoid calling the callback inside the 
+        * lock, which could lead to deadlocks.
+        */
+       EnterCriticalSection (&assemblies_mutex);
+       copy = g_list_copy (loaded_assemblies);
+       LeaveCriticalSection (&assemblies_mutex);
 
        g_list_foreach (loaded_assemblies, func, user_data);
+
+       g_list_free (copy);
 }
 
 /* Holds the assembly of the application, for
@@ -509,3 +1053,5 @@ mono_assembly_get_main (void)
 {
        return(main_assembly);
 }
+
+