ltt/branches/poly/lttv/module.c

   1
   2 /* module.c : Implementation of the module loading/unloading mechanism.
   3  *
   4  */
   5
   6 #include <lttv/module.h>
   7
   8
   9 struct _LttvModule
  10 {
  11   GModule *module;
  12   guint ref_count;
  13   guint load_count;
  14   GPtrArray *dependents;
  15 };
  16
  17
  18 /* Table of loaded modules and paths where to search for modules */
  19
  20 static GHashTable *modules = NULL;
  21
  22 static GPtrArray *modulesPaths = NULL;
  23
  24 static void lttv_module_unload_all();
  25
  26
  27 void lttv_module_init(int argc, char **argv)
  28 {
  29   modules = g_hash_table_new(g_str_hash, g_str_equal);
  30   modulesPaths = g_ptr_array_new();
  31 }
  32
  33
  34 void lttv_module_destroy()
  35 {
  36   int i;
  37
  38   /* Unload all modules */
  39   lttv_module_unload_all();
  40
  41   /* Free the modules paths pointer array as well as the elements */
  42   for(i = 0; i < modulesPaths->len ; i++) {
  43     g_free(modulesPaths->pdata[i]);
  44   }
  45   g_ptr_array_free(modulesPaths,TRUE) ;
  46   modulesPaths = NULL;
  47
  48   /* destroy the hash table */
  49   g_hash_table_destroy(modules) ;
  50   modules = NULL;
  51 }
  52
  53
  54 /* Add a new pathname to the modules loading search path */
  55
  56 void lttv_module_path_add(const char *name)
  57 {
  58   g_ptr_array_add(modulesPaths,(char*)g_strdup(name));
  59 }
  60
  61
  62 static LttvModule *
  63 module_load(const char *name, int argc, char **argv)
  64 {
  65   GModule *gm;
  66
  67   LttvModule *m;
  68
  69   int i;
  70
  71   char *pathname;
  72
  73   const char *module_name;
  74
  75   LttvModuleInit init_function;
  76
  77   /* Try to find the module along all the user specified paths */
  78
  79   for(i = 0 ; i < modulesPaths->len ; i++) {
  80     pathname = g_module_build_path(modulesPaths->pdata[i],name);
  81     gm = g_module_open(pathname,G_MODULE_BIND_LAZY);
  82         g_critical("module : %s", pathname);
  83         g_critical("erreur : %s", g_module_error());
  84     g_free(pathname);
  85
  86     if(gm != NULL) break;
  87   }
  88
  89   /* Try the default system path */
  90
  91   if(gm == NULL) {
  92     pathname = g_module_build_path(NULL,name);
  93     gm = g_module_open(pathname,G_MODULE_BIND_LAZY);
  94         g_critical("module : %s", pathname);
  95     g_free(pathname);
  96   }
  97
  98   /* Module cannot be found */
  99   if(gm==NULL)
 100         g_critical("module est null");
 101   if(gm == NULL) return NULL;
 102
 103   /* Check if the module was already opened using the hopefully canonical name
 104      returned by g_module_name. */
 105
 106   module_name = g_module_name(gm);
 107
 108   m = g_hash_table_lookup(modules, module_name);
 109
 110   if(m == NULL) {
 111
 112     /* Module loaded for the first time. Insert it in the table and call the
 113        init function if any. */
 114
 115     m = g_new(LttvModule, 1);
 116     m->module = gm;
 117     m->ref_count = 0;
 118     m->load_count = 0;
 119     m->dependents = g_ptr_array_new();
 120     g_hash_table_insert(modules, (gpointer)module_name, m);
 121
 122     if(!g_module_symbol(gm, "init", (gpointer)&init_function)) {
 123       g_warning("module %s (%s) has no init function", name, pathname);
 124     }
 125     else init_function(m, argc, argv);
 126   }
 127   else {
 128
 129     /* Module was already opened, check that it really is the same and
 130        undo the extra g_module_open */
 131
 132     if(m->module != gm) g_error("Two gmodules with the same pathname");
 133     g_module_close(gm);
 134   }
 135
 136   m->ref_count++;
 137   return m;
 138 }
 139
 140
 141 LttvModule *
 142 lttv_module_load(const char *name, int argc, char **argv)
 143 {
 144   LttvModule *m = module_load(name, argc, argv);
 145   if(m != NULL) m->load_count++;
 146   return m;
 147 }
 148
 149
 150 LttvModule *
 151 lttv_module_require(LttvModule *m, const char *name, int argc, char **argv)
 152 {
 153   LttvModule *module;
 154
 155   module = module_load(name, argc, argv);
 156   if(module != NULL) g_ptr_array_add(m->dependents, module);
 157   return module;
 158 }
 159
 160
 161 static void module_unload(LttvModule *m)
 162 {
 163   LttvModuleDestroy destroy_function;
 164
 165   char *pathname;
 166
 167   guint i, len;
 168
 169   /* Decrement the reference count */
 170
 171   m->ref_count--;
 172   if(m->ref_count > 0) return;
 173
 174   /* We really have to unload the module, first unload its dependents */
 175
 176   len = m->dependents->len;
 177
 178   for(i = 0 ; i < len ; i++) {
 179     module_unload(m->dependents->pdata[i]);
 180   }
 181
 182   if(len != m->dependents->len) g_error("dependents list modified");
 183
 184   /* Unload the module itself */
 185
 186   if(!g_module_symbol(m->module, "destroy", (gpointer)&destroy_function)) {
 187     g_warning("module (%s) has no destroy function", pathname);
 188   }
 189   else destroy_function();
 190
 191   g_hash_table_remove(modules, g_module_name(m->module));
 192   g_ptr_array_free(m->dependents, TRUE);
 193   g_module_close(m->module);
 194   g_free(m);
 195 }
 196
 197
 198 void lttv_module_unload(LttvModule *m)
 199 {
 200   if(m->load_count <= 0) {
 201     g_error("more unload than load (%s)", g_module_name(m->module));
 202     return;
 203   }
 204   m->load_count--;
 205   module_unload(m);
 206 }
 207
 208
 209 static void
 210 list_modules(gpointer key, gpointer value, gpointer user_data)
 211 {
 212   g_ptr_array_add((GPtrArray *)user_data, value);
 213 }
 214
 215
 216 LttvModule **
 217 lttv_module_list(guint *nb)
 218 {
 219   GPtrArray *list = g_ptr_array_new();
 220
 221   LttvModule **array;
 222
 223   g_hash_table_foreach(modules, list_modules, list);
 224   *nb = list->len;
 225   array = (LttvModule **)list->pdata;
 226   g_ptr_array_free(list, FALSE);
 227   return array;
 228 }
 229
 230
 231 LttvModule **
 232 lttv_module_info(LttvModule *m, const char **name,
 233     guint *ref_count, guint *load_count, guint *nb_dependents)
 234 {
 235   guint i, len = m->dependents->len;
 236
 237   LttvModule **array = g_new(LttvModule *, len);
 238
 239   *name = g_module_name(m->module);
 240   *ref_count = m->ref_count;
 241   *load_count = m->load_count;
 242   *nb_dependents = len;
 243   for(i = 0 ; i < len ; i++) array[i] = m->dependents->pdata[i];
 244   return array;
 245 }
 246
 247
 248 static void
 249 list_independent(gpointer key, gpointer value, gpointer user_data)
 250 {
 251   LttvModule *m = (LttvModule *)value;
 252
 253   if(m->load_count > 0) g_ptr_array_add((GPtrArray *)user_data, m);
 254 }
 255
 256
 257 void
 258 lttv_module_unload_all()
 259 {
 260   guint i;
 261
 262   LttvModule *m;
 263
 264   GPtrArray *independent_modules = g_ptr_array_new();
 265
 266   g_hash_table_foreach(modules, list_independent, independent_modules);
 267
 268   for(i = 0 ; i < independent_modules->len ; i++) {
 269     m = (LttvModule *)independent_modules->pdata[i];
 270     while(m->load_count > 0) lttv_module_unload(m);
 271   }
 272
 273   g_ptr_array_free(independent_modules, TRUE);
 274   if(g_hash_table_size(modules) != 0) g_warning("cannot unload all modules");
 275 }