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("loading module : %s", pathname);
  83         g_critical("module error : %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("loading module : %s", pathname);
  95     g_free(pathname);
  96   }
  97
  98   /* Module cannot be found */
  99   if(gm == NULL) return NULL;
 100
 101   /* Check if the module was already opened using the hopefully canonical name
 102      returned by g_module_name. */
 103
 104   module_name = g_module_name(gm);
 105
 106   m = g_hash_table_lookup(modules, module_name);
 107
 108   if(m == NULL) {
 109
 110     /* Module loaded for the first time. Insert it in the table and call the
 111        init function if any. */
 112
 113     m = g_new(LttvModule, 1);
 114     m->module = gm;
 115     m->ref_count = 0;
 116     m->load_count = 0;
 117     m->dependents = g_ptr_array_new();
 118     g_hash_table_insert(modules, (gpointer)module_name, m);
 119
 120     if(!g_module_symbol(gm, "init", (gpointer)&init_function)) {
 121       g_warning("module %s (%s) has no init function", name, pathname);
 122     }
 123     else init_function(m, argc, argv);
 124   }
 125   else {
 126
 127     /* Module was already opened, check that it really is the same and
 128        undo the extra g_module_open */
 129
 130     if(m->module != gm) g_error("Two gmodules with the same pathname");
 131     g_module_close(gm);
 132   }
 133
 134   m->ref_count++;
 135   return m;
 136 }
 137
 138
 139 LttvModule *
 140 lttv_module_load(const char *name, int argc, char **argv)
 141 {
 142   LttvModule *m = module_load(name, argc, argv);
 143   if(m != NULL) m->load_count++;
 144   return m;
 145 }
 146
 147
 148 LttvModule *
 149 lttv_module_require(LttvModule *m, const char *name, int argc, char **argv)
 150 {
 151   LttvModule *module;
 152
 153   module = module_load(name, argc, argv);
 154   if(module != NULL) g_ptr_array_add(m->dependents, module);
 155   return module;
 156 }
 157
 158
 159 static void module_unload(LttvModule *m)
 160 {
 161   LttvModuleDestroy destroy_function;
 162
 163   char *pathname;
 164
 165   guint i, len;
 166
 167   /* Decrement the reference count */
 168
 169   m->ref_count--;
 170   if(m->ref_count > 0) return;
 171
 172   /* We really have to unload the module, first unload its dependents */
 173
 174   len = m->dependents->len;
 175
 176   for(i = 0 ; i < len ; i++) {
 177     module_unload(m->dependents->pdata[i]);
 178   }
 179
 180   if(len != m->dependents->len) g_error("dependents list modified");
 181
 182   /* Unload the module itself */
 183
 184   if(!g_module_symbol(m->module, "destroy", (gpointer)&destroy_function)) {
 185     g_warning("module (%s) has no destroy function", pathname);
 186   }
 187   else destroy_function();
 188
 189   g_hash_table_remove(modules, g_module_name(m->module));
 190   g_ptr_array_free(m->dependents, TRUE);
 191   g_module_close(m->module);
 192   g_free(m);
 193 }
 194
 195
 196 void lttv_module_unload(LttvModule *m)
 197 {
 198   if(m->load_count <= 0) {
 199     g_error("more unload than load (%s)", g_module_name(m->module));
 200     return;
 201   }
 202   m->load_count--;
 203   module_unload(m);
 204 }
 205
 206
 207 static void
 208 list_modules(gpointer key, gpointer value, gpointer user_data)
 209 {
 210   g_ptr_array_add((GPtrArray *)user_data, value);
 211 }
 212
 213
 214 LttvModule **
 215 lttv_module_list(guint *nb)
 216 {
 217   GPtrArray *list = g_ptr_array_new();
 218
 219   LttvModule **array;
 220
 221   g_hash_table_foreach(modules, list_modules, list);
 222   *nb = list->len;
 223   array = (LttvModule **)list->pdata;
 224   g_ptr_array_free(list, FALSE);
 225   return array;
 226 }
 227
 228
 229 LttvModule **
 230 lttv_module_info(LttvModule *m, const char **name,
 231     guint *ref_count, guint *load_count, guint *nb_dependents)
 232 {
 233   guint i, len = m->dependents->len;
 234
 235   LttvModule **array = g_new(LttvModule *, len);
 236
 237   *name = g_module_name(m->module);
 238   *ref_count = m->ref_count;
 239   *load_count = m->load_count;
 240   *nb_dependents = len;
 241   for(i = 0 ; i < len ; i++) array[i] = m->dependents->pdata[i];
 242   return array;
 243 }
 244
 245
 246 static void
 247 list_independent(gpointer key, gpointer value, gpointer user_data)
 248 {
 249   LttvModule *m = (LttvModule *)value;
 250
 251   if(m->load_count > 0) g_ptr_array_add((GPtrArray *)user_data, m);
 252 }
 253
 254
 255 void
 256 lttv_module_unload_all()
 257 {
 258   guint i;
 259
 260   LttvModule *m;
 261
 262   GPtrArray *independent_modules = g_ptr_array_new();
 263
 264   g_hash_table_foreach(modules, list_independent, independent_modules);
 265
 266   for(i = 0 ; i < independent_modules->len ; i++) {
 267     m = (LttvModule *)independent_modules->pdata[i];
 268     while(m->load_count > 0) lttv_module_unload(m);
 269   }
 270
 271   g_ptr_array_free(independent_modules, TRUE);
 272   if(g_hash_table_size(modules) != 0) g_warning("cannot unload all modules");
 273 }