+
/* This file is part of the Linux Trace Toolkit viewer
* Copyright (C) 2003-2004 Michel Dagenais
*
*/
-/* module.c : Implementation of the module loading/unloading mechanism.
- *
- */
+/* module.c : Implementation of the module loading/unloading mechanism. */
#include <lttv/module.h>
+#include <gmodule.h>
+
+
+struct _LttvLibrary
+{
+ LttvLibraryInfo info;
+ GPtrArray *modules;
+ GModule *gm;
+ guint locked_loaded;
+};
+
struct _LttvModule
{
- GModule *module;
- guint ref_count;
- guint load_count;
- GPtrArray *dependents;
+ LttvModuleInfo info;
+ char **prerequisites_names;
+ GPtrArray *prerequisites;
};
-/* Table of loaded modules and paths where to search for modules */
+/* Modules are searched by name. However, a library may be loaded which
+ provides a module with the same name as an existing one. A stack of
+ modules is thus maintained for each name.
+
+ Libraries correspond to glib modules. The g_module function is
+ responsible for loading each library only once. */
+
+static GHashTable *modules_by_name = NULL;
-static GHashTable *modules = NULL;
+static GPtrArray *libraries = NULL;
-static GPtrArray *modulesPaths = NULL;
+static GHashTable *libraries_by_g_module = NULL;
-static void lttv_module_unload_all();
+static GPtrArray *library_paths = NULL;
+static gboolean initialized = FALSE;
-void lttv_module_init(int argc, char **argv)
+static gboolean destroyed = TRUE;
+
+static struct _LttvModuleDescription *builtin_chain = NULL;
+
+static struct _LttvModuleDescription *module_chain = NULL;
+
+static struct _LttvModuleDescription **module_next = &module_chain;
+
+static GQuark lttv_module_error;
+
+static void init();
+
+static finish_destroy();
+
+static void module_release(LttvModule *m);
+
+
+static LttvLibrary *library_add(char *name, char *path, GModule *gm)
{
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Init module.c");
- modules = g_hash_table_new(g_str_hash, g_str_equal);
- modulesPaths = g_ptr_array_new();
-}
+ LttvLibrary *l;
+ LttvModule *m;
-void lttv_module_destroy()
-{
- int i;
+ struct _LttvModuleDescription *link;
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Destroy module.c");
+ GPtrArray *modules;
+
+ l = g_new(LttvLibrary, 1);
+ l->modules = g_ptr_array_new();
+ l->gm = gm;
+ l->locked_loaded = 0;
+ l->info.name = g_strdup(name);
+ l->info.path = g_strdup(path);
+ l->info.load_count = 0;
- /* Unload all modules */
- lttv_module_unload_all();
+ g_ptr_array_add(libraries, l);
+ g_hash_table_insert(libraries_by_g_module, gm, l);
- /* Free the modules paths pointer array as well as the elements */
- for(i = 0; i < modulesPaths->len ; i++) {
- g_free(modulesPaths->pdata[i]);
+ *module_next = NULL;
+ for(link = module_chain; link != NULL; link = link->next) {
+ m = g_new(LttvModule, 1);
+ g_ptr_array_add(l->modules, m);
+
+ modules = g_hash_table_lookup(modules_by_name, link->name);
+ if(modules == NULL) {
+ modules = g_ptr_array_new();
+ g_hash_table_insert(modules_by_name, g_strdup(link->name), modules);
+ }
+ g_ptr_array_add(modules, m);
+
+ m->prerequisites_names = link->prerequisites;
+ m->prerequisites = g_ptr_array_new();
+ m->info.name = link->name;
+ m->info.short_description = link->short_description;
+ m->info.description = link->description;
+ m->info.init = link->init;
+ m->info.destroy = link->destroy;
+ m->info.library = l;
+ m->info.require_count = 0;
+ m->info.use_count = 0;
+ m->info.prerequisites_number = link->prerequisites_number;
}
- g_ptr_array_free(modulesPaths,TRUE) ;
- modulesPaths = NULL;
-
- /* destroy the hash table */
- g_hash_table_destroy(modules) ;
- modules = NULL;
+ return l;
}
-/* Add a new pathname to the modules loading search path */
-
-void lttv_module_path_add(const char *name)
+static void library_remove(LttvLibrary *l)
{
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Add module path %s", name);
- g_ptr_array_add(modulesPaths,(char*)g_strdup(name));
+ LttvModule *m;
+
+ GPtrArray *modules;
+
+ guint i;
+
+ char *key;
+
+ for(i = 0 ; i < l->modules->len ; i++) {
+ m = (LttvModule *)(l->modules->pdata[i]);
+
+ g_hash_table_lookup_extended(modules_by_name, m->info.name,
+ (gpointer *)&key, (gpointer *)&modules);
+ g_assert(modules != NULL);
+ g_ptr_array_remove(modules, m);
+ if(modules->len == 0) {
+ g_hash_table_remove(modules_by_name, m->info.name);
+ g_ptr_array_free(modules, TRUE);
+ g_free(key);
+ }
+
+ g_ptr_array_free(m->prerequisites, TRUE);
+ g_free(m);
+ }
+
+ g_ptr_array_remove(libraries, l);
+ g_hash_table_remove(libraries_by_g_module, l->gm);
+ g_ptr_array_free(l->modules, TRUE);
+ g_free(l->info.name);
+ g_free(l->info.path);
+ g_free(l);
}
-static LttvModule *
-module_load(const char *name, int argc, char **argv)
+static LttvLibrary *library_load(char *name, GError **error)
{
GModule *gm;
- LttvModule *m;
+ int i, nb;
+
+ char *path, *pathname;
+
+ LttvLibrary *l;
- int i;
+ GString *messages = g_string_new("");
- char *pathname;
+ /* insure that module.c is initialized */
- const char *module_name;
-
- LttvModuleInit init_function;
+ init();
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Load module %s", name);
+ /* Try to find the library along all the user specified paths */
- /* Try to find the module along all the user specified paths */
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Load library %s", name);
+ nb = lttv_library_path_number();
+ for(i = 0 ; i <= nb ; i++) {
+ if(i < nb) path = lttv_library_path_get(i);
+ else path = NULL;
- for(i = 0 ; i < modulesPaths->len ; i++) {
- pathname = g_module_build_path(modulesPaths->pdata[i],name);
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, "Try path %s", pathname);
+ pathname = g_module_build_path(path ,name);
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Try path %s", pathname);
+ module_chain = NULL;
+ module_next = &module_chain;
gm = g_module_open(pathname,0);
g_free(pathname);
if(gm != NULL) break;
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,"Trial failed, %s",g_module_error());
- }
-
- /* Try the default system path */
- if(gm == NULL) {
- pathname = g_module_build_path(NULL,name);
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, "Try default path");
- gm = g_module_open(pathname,0);
- g_free(pathname);
+ g_string_append(messages, g_module_error());
+ g_string_append(messages, "\n");
+ g_log(G_LOG_DOMAIN,G_LOG_LEVEL_INFO,"Trial failed, %s", g_module_error());
}
/* Module cannot be found */
+
if(gm == NULL) {
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,"Trial failed, %s",g_module_error());
- g_warning("Failed to load module %s", name);
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Failed to load %s", name);
+ g_set_error(error, lttv_module_error, LTTV_MODULE_NOT_FOUND,
+ "Cannot load library %s: %s", name, messages->str);
+ g_string_free(messages, TRUE);
return NULL;
}
+ g_string_free(messages, TRUE);
+
+ /* Check if the library was already loaded */
+
+ l = g_hash_table_lookup(libraries_by_g_module, gm);
- /* Check if the module was already opened using the hopefully canonical name
- returned by g_module_name. */
+ /* This library was not already loaded */
- module_name = g_module_name(gm);
+ if(l == NULL) {
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Library %s (%s) loaded", name,
+ g_module_name(gm));
+ l = library_add(name, path, gm);
+ }
+ return l;
+}
- m = g_hash_table_lookup(modules, module_name);
- if(m == NULL) {
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,
- "Module %s (%s) loaded, call its init function", name, module_name);
+LttvLibrary *lttv_library_load(char *name, GError **error)
+{
+ LttvLibrary *l = library_load(name, error);
+ l->info.load_count++;
+ return l;
+}
- /* Module loaded for the first time. Insert it in the table and call the
- init function if any. */
- m = g_new(LttvModule, 1);
- m->module = gm;
- m->ref_count = 0;
- m->load_count = 0;
- m->dependents = g_ptr_array_new();
- g_hash_table_insert(modules, (gpointer)module_name, m);
-
- if(!g_module_symbol(gm, "init", (gpointer)&init_function)) {
- g_warning("module %s (%s) has no init function", name, pathname);
- }
- else init_function(m, argc, argv);
+static void library_unload(LttvLibrary *l)
+{
+ guint i, len;
+
+ GModule *gm;
+
+ LttvModule *m;
+
+ if(l->locked_loaded > 0) {
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload library %s: locked loaded",
+ l->info.name);
+ return;
+ }
+
+ if(l->info.load_count > 0) {
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload library %s: load count %d",
+ l->info.name, l->info.load_count);
+ return;
}
- else {
- /* Module was already opened, check that it really is the same and
- undo the extra g_module_open */
+ /* Check if all its modules have been released */
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,
- "Module %s (%s) was already loaded, no need to call init function",
- name, module_name);
- if(m->module != gm) g_error("Two gmodules with the same pathname");
- g_module_close(gm);
+ for(i = 0 ; i < l->modules->len ; i++) {
+ m = (LttvModule *)(l->modules->pdata[i]);
+ if(m->info.use_count > 0) {
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO,"Unload library %s: module %s used",
+ l->info.name, m->info.name);
+ return;
+ }
}
-
- m->ref_count++;
- return m;
+
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload library %s: close the GModule",
+ l->info.name);
+ gm = l->gm;
+ library_remove(l);
+ if(gm != NULL) g_module_close(gm);
+
+ /* insure that module.c will be finalized */
+
+ finish_destroy();
}
-LttvModule *
-lttv_module_load(const char *name, int argc, char **argv)
+void lttv_library_unload(LttvLibrary *l)
{
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Load module %s explicitly", name);
- LttvModule *m = module_load(name, argc, argv);
- if(m != NULL) m->load_count++;
- return m;
+ l->info.load_count--;
+ library_unload(l);
}
-LttvModule *
-lttv_module_require(LttvModule *m, const char *name, int argc, char **argv)
+static void library_lock_loaded(LttvLibrary *l)
{
- LttvModule *module;
-
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO,
- "Load module %s, as %s is a dependent requiring it", name,
- g_module_name(m->module));
- module = module_load(name, argc, argv);
- if(module != NULL) g_ptr_array_add(m->dependents, module);
- return module;
+ l->locked_loaded++;
}
-static void module_unload(LttvModule *m)
+static void library_unlock_loaded(LttvLibrary *l)
{
- LttvModuleDestroy destroy_function;
+ l->locked_loaded--;
+ library_unload(l);
+}
- char *pathname;
- guint i, len;
+static LttvModule *module_require(char *name, GError **error)
+{
+ GError *tmp_error = NULL;
- /* Decrement the reference count */
+ guint i, j;
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload module %s",
- g_module_name(m->module));
- m->ref_count--;
- if(m->ref_count > 0) {
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,
- "Module usage count decremented to %d", m->ref_count);
- return;
- }
+ LttvModule *m, *required;
+
+ LttvLibrary *l = NULL;
+
+ GPtrArray *modules;
+
+ /* Insure that module.c is initialized */
+
+ init();
- /* We really have to unload the module. First destroy it. */
+ /* Check if the module is already loaded */
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,
- "Call the destroy function and unload the module");
- if(!g_module_symbol(m->module, "destroy", (gpointer)&destroy_function)) {
- g_warning("module (%s) has no destroy function", pathname);
+ modules = g_hash_table_lookup(modules_by_name, name);
+
+ /* Try to load a library having the module name */
+
+ if(modules == NULL) {
+ l = library_load(name, error);
+ if(l == NULL) return NULL;
+ else library_lock_loaded(l);
+
+ /* A library was found, does it contain the named module */
+
+ modules = g_hash_table_lookup(modules_by_name, name);
+ if(modules == NULL) {
+ g_set_error(error, lttv_module_error, LTTV_MODULE_NOT_FOUND,
+ "Module %s not found in library %s", name, l->info.name);
+ library_unlock_loaded(l);
+ return NULL;
+ }
}
- else destroy_function();
+ m = (LttvModule *)(modules->pdata[modules->len - 1]);
- /* Then release the modules required by this module */
+ /* We have the module */
- len = m->dependents->len;
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload dependent modules");
+ m->info.use_count++;
- for(i = 0 ; i < len ; i++) {
- module_unload(m->dependents->pdata[i]);
+ /* First use of the module. Initialize after getting the prerequisites */
+
+ if(m->info.use_count == 1) {
+ for(i = 0 ; i < m->info.prerequisites_number ; i++) {
+ required = module_require(m->prerequisites_names[i], &tmp_error);
+
+ /* A prerequisite could not be found, undo everything and fail */
+
+ if(required == NULL) {
+ for(j = 0 ; j < m->prerequisites->len ; j++) {
+ module_release((LttvModule *)(m->prerequisites->pdata[j]));
+ }
+ g_ptr_array_set_size(m->prerequisites, 0);
+ if(l != NULL) library_unlock_loaded(l);
+ g_set_error(error, lttv_module_error, LTTV_MODULE_NOT_FOUND,
+ "Cannot find prerequisite for module %s: %s", name,
+ tmp_error->message);
+ g_clear_error(&tmp_error);
+ return NULL;
+ }
+ g_ptr_array_add(m->prerequisites, required);
+ }
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Module %s: init()", m->info.name);
+ m->info.init();
}
- if(len != m->dependents->len) g_error("dependents list modified");
+ /* Decrement the load count of the library. It will not really be
+ unloaded since it contains a currently used module. */
+
+ if(l != NULL) library_unlock_loaded(l);
- /* Finally remove any trace of this module */
+ return(m);
+}
+
+
+/* The require_count for a module is the number of explicit calls to
+ lttv_module_require, while the use_count also counts the number of times
+ a module is needed as a prerequisite. */
- g_hash_table_remove(modules, g_module_name(m->module));
- g_ptr_array_free(m->dependents, TRUE);
- g_module_close(m->module);
- g_free(m);
+LttvModule *lttv_module_require(char *name, GError **error)
+{
+ LttvModule *m = module_require(name, error);
+ if(m != NULL) m->info.require_count++;
+ return(m);
}
-void lttv_module_unload(LttvModule *m)
+static void module_release(LttvModule *m)
{
- g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Explicitly unload module %s",
- g_module_name(m->module));
- if(m->load_count <= 0) {
- g_error("more unload than load (%s)", g_module_name(m->module));
- return;
+ guint i;
+
+ library_lock_loaded(m->info.library);
+
+ m->info.use_count--;
+ if(m->info.use_count == 0) {
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Module %s: destroy()",m->info.name);
+ m->info.destroy();
+ for(i = 0 ; i < m->prerequisites->len ; i++) {
+ module_release((LttvModule *)(m->prerequisites->pdata[i]));
+ }
+ g_ptr_array_set_size(m->prerequisites, 0);
}
- m->load_count--;
- module_unload(m);
+ library_unlock_loaded(m->info.library);
+}
+
+
+void lttv_module_release(LttvModule *m)
+{
+ m->info.require_count--;
+ module_release(m);
+}
+
+
+void lttv_module_info(LttvModule *m, LttvModuleInfo *info)
+{
+ *info = m->info;
+}
+
+
+unsigned lttv_module_prerequisite_number(LttvModule *m)
+{
+ return m->prerequisites->len;
+}
+
+
+LttvModule *lttv_module_prerequisite_get(LttvModule *m, unsigned i)
+{
+ return (LttvModule *)(m->prerequisites->pdata[i]);
+}
+
+
+void lttv_library_info(LttvLibrary *l, LttvLibraryInfo *info)
+{
+ *info = l->info;
+}
+
+
+unsigned lttv_library_module_number(LttvLibrary *l)
+{
+ return l->modules->len;
+}
+
+
+LttvModule *lttv_library_module_get(LttvLibrary *l, unsigned i)
+{
+ return (LttvModule *)(l->modules->pdata[i]);
+}
+
+
+unsigned lttv_library_number()
+{
+ return libraries->len;
}
-static void
-list_modules(gpointer key, gpointer value, gpointer user_data)
+LttvLibrary *lttv_library_get(unsigned i)
{
- g_ptr_array_add((GPtrArray *)user_data, value);
+ return (LttvLibrary *)(libraries->pdata[i]);
}
-LttvModule **
-lttv_module_list(guint *nb)
+void lttv_library_path_add(char *name)
{
- GPtrArray *list = g_ptr_array_new();
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Add library path %s", name);
+ g_ptr_array_add(library_paths,(char*)g_strdup(name));
+}
+
- LttvModule **array;
+void lttv_library_path_remove(char *name)
+{
+ guint i;
- g_hash_table_foreach(modules, list_modules, list);
- *nb = list->len;
- array = (LttvModule **)list->pdata;
- g_ptr_array_free(list, FALSE);
- return array;
+ for(i = 0 ; i < library_paths->len ; i++) {
+ if(g_str_equal(name, library_paths->pdata[i])) {
+ g_free(library_paths->pdata[i]);
+ g_ptr_array_remove_index(library_paths,i);
+ return;
+ }
+ }
}
-LttvModule **
-lttv_module_info(LttvModule *m, const char **name,
- guint *ref_count, guint *load_count, guint *nb_dependents)
+unsigned lttv_library_path_number()
{
- guint i, len = m->dependents->len;
+ return library_paths->len;
+}
- LttvModule **array = g_new(LttvModule *, len);
- *name = g_module_name(m->module);
- *ref_count = m->ref_count;
- *load_count = m->load_count;
- *nb_dependents = len;
- for(i = 0 ; i < len ; i++) array[i] = m->dependents->pdata[i];
- return array;
+char *lttv_library_path_get(unsigned i)
+{
+ return (char *)(library_paths->pdata[library_paths->len - i - 1]);
}
-char *
-lttv_module_name(LttvModule *m)
+
+void lttv_module_register(struct _LttvModuleDescription *d)
{
- return g_module_name(m->module);
+ *module_next = d;
+ module_next = &(d->next);
}
-static void
-list_independent(gpointer key, gpointer value, gpointer user_data)
+
+static void init()
{
- LttvModule *m = (LttvModule *)value;
+ if(initialized) return;
+ g_assert(destroyed);
+
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Init module.c");
- if(m->load_count > 0) g_ptr_array_add((GPtrArray *)user_data, m);
+ initialized = TRUE;
+ destroyed = FALSE;
+ lttv_module_error = g_quark_from_string("LTTV_MODULE_ERROR");
+ modules_by_name = g_hash_table_new(g_str_hash, g_str_equal);
+ libraries = g_ptr_array_new();
+ libraries_by_g_module = g_hash_table_new(g_direct_hash, g_direct_equal);
+ library_paths = g_ptr_array_new();
+
+ if(builtin_chain == NULL) builtin_chain = module_chain;
+ module_chain = builtin_chain;
+ library_add("builtin", NULL, NULL);
}
-void
-lttv_module_unload_all()
+static finish_destroy()
{
guint i;
+ if(initialized) return;
+ g_assert(!destroyed);
+
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Finish destroy module.c");
+ g_hash_table_destroy(modules_by_name);
+ g_ptr_array_free(libraries, TRUE);
+ g_hash_table_destroy(libraries_by_g_module);
+ for(i = 0 ; i < library_paths->len ; i++) {
+ g_free(library_paths->pdata[i]);
+ }
+ g_ptr_array_free(library_paths, TRUE);
+ destroyed = TRUE;
+}
+
+
+static void destroy()
+{
+ guint i, j, nb;
+
+ LttvLibrary *l, **locked_libraries;
+
LttvModule *m;
- GPtrArray *independent_modules;
+ g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Destroy module.c");
+
+ /* Unload all libraries */
- while(g_hash_table_size(modules) != 0) {
- independent_modules = g_ptr_array_new();
- g_hash_table_foreach(modules, list_independent, independent_modules);
+ nb = libraries->len;
+ locked_libraries = g_new(LttvLibrary *, nb);
- for(i = 0 ; i < independent_modules->len ; i++) {
- m = (LttvModule *)independent_modules->pdata[i];
- lttv_module_unload(m);
+ for(i = 0 ; i < nb ; i++) {
+ l = (LttvLibrary *)(libraries->pdata[i]);
+ locked_libraries[i] = l;
+ library_lock_loaded(l);
+ for(j = 0 ; j < l->modules->len ; j++) {
+ m = (LttvModule *)(l->modules->pdata[j]);
+ while(m->info.require_count > 0) lttv_module_release(m);
}
- g_ptr_array_free(independent_modules, TRUE);
+ while(l->info.load_count > 0) lttv_library_unload(l);
+ }
+
+ for(i = 0 ; i < nb ; i++) {
+ l = locked_libraries[i];
+ library_unlock_loaded(l);
}
+ g_free(locked_libraries);
+
+ /* The library containing module.c may be locked by our caller */
+
+ g_assert(libraries->len <= 1);
+
+ initialized = FALSE;
}
+
+LTTV_MODULE("module", "Modules in libraries", \
+ "Load libraries, list, require and initialize contained modules", \
+ init, destroy)
+
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