ltt/branches/poly/lttv/main/module.c

   1 /* This file is part of the Linux Trace Toolkit viewer
   2  * Copyright (C) 2003-2004 Michel Dagenais
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License Version 2 as
   6  * published by the Free Software Foundation;
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  16  * MA 02111-1307, USA.
  17  */
  18
  19
  20 /* module.c : Implementation of the module loading/unloading mechanism.
  21  *
  22  */
  23
  24 #include <lttv/module.h>
  25
  26 struct _LttvModule
  27 {
  28   GModule *module;
  29   guint ref_count;
  30   guint load_count;
  31   GPtrArray *dependents;
  32 };
  33
  34
  35 /* Table of loaded modules and paths where to search for modules */
  36
  37 static GHashTable *modules = NULL;
  38
  39 static GPtrArray *modulesPaths = NULL;
  40
  41 static void lttv_module_unload_all();
  42
  43
  44 void lttv_module_init(int argc, char **argv)
  45 {
  46   g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Init module.c");
  47   modules = g_hash_table_new(g_str_hash, g_str_equal);
  48   modulesPaths = g_ptr_array_new();
  49 }
  50
  51
  52 void lttv_module_destroy()
  53 {
  54   int i;
  55
  56   g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Destroy module.c");
  57
  58   /* Unload all modules */
  59   lttv_module_unload_all();
  60
  61   /* Free the modules paths pointer array as well as the elements */
  62   for(i = 0; i < modulesPaths->len ; i++) {
  63     g_free(modulesPaths->pdata[i]);
  64   }
  65   g_ptr_array_free(modulesPaths,TRUE) ;
  66   modulesPaths = NULL;
  67
  68   /* destroy the hash table */
  69   g_hash_table_destroy(modules) ;
  70   modules = NULL;
  71 }
  72
  73
  74 /* Add a new pathname to the modules loading search path */
  75
  76 void lttv_module_path_add(const char *name)
  77 {
  78   g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Add module path %s", name);
  79   g_ptr_array_add(modulesPaths,(char*)g_strdup(name));
  80 }
  81
  82
  83 static LttvModule *
  84 module_load(const char *name, int argc, char **argv)
  85 {
  86   GModule *gm;
  87
  88   LttvModule *m;
  89
  90   int i;
  91
  92   char *pathname;
  93
  94   const char *module_name;
  95
  96   LttvModuleInit init_function;
  97
  98   g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Load module %s", name);
  99
 100   /* Try to find the module along all the user specified paths */
 101
 102   for(i = 0 ; i < modulesPaths->len ; i++) {
 103     pathname = g_module_build_path(modulesPaths->pdata[i],name);
 104     g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, "Try path %s", pathname);
 105     gm = g_module_open(pathname,0);
 106     g_free(pathname);
 107
 108     if(gm != NULL) break;
 109     g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,"Trial failed, %s",g_module_error());
 110   }
 111
 112   /* Try the default system path */
 113
 114   if(gm == NULL) {
 115     pathname = g_module_build_path(NULL,name);
 116     g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, "Try default path");
 117     gm = g_module_open(pathname,0);
 118     g_free(pathname);
 119   }
 120
 121   /* Module cannot be found */
 122   if(gm == NULL) {
 123     g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,"Trial failed, %s",g_module_error());
 124     g_warning("Failed to load module %s", name);
 125     return NULL;
 126   }
 127
 128   /* Check if the module was already opened using the hopefully canonical name
 129      returned by g_module_name. */
 130
 131   module_name = g_module_name(gm);
 132
 133   m = g_hash_table_lookup(modules, module_name);
 134
 135   if(m == NULL) {
 136     g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,
 137         "Module %s (%s) loaded, call its init function", name, module_name);
 138
 139     /* Module loaded for the first time. Insert it in the table and call the
 140        init function if any. */
 141
 142     m = g_new(LttvModule, 1);
 143     m->module = gm;
 144     m->ref_count = 0;
 145     m->load_count = 0;
 146     m->dependents = g_ptr_array_new();
 147     g_hash_table_insert(modules, (gpointer)module_name, m);
 148
 149     if(!g_module_symbol(gm, "init", (gpointer)&init_function)) {
 150       g_warning("module %s (%s) has no init function", name, pathname);
 151     }
 152     else init_function(m, argc, argv);
 153   }
 154   else {
 155
 156     /* Module was already opened, check that it really is the same and
 157        undo the extra g_module_open */
 158
 159     g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,
 160         "Module %s (%s) was already loaded, no need to call init function",
 161         name, module_name);
 162     if(m->module != gm) g_error("Two gmodules with the same pathname");
 163     g_module_close(gm);
 164   }
 165
 166   m->ref_count++;
 167   return m;
 168 }
 169
 170
 171 LttvModule *
 172 lttv_module_load(const char *name, int argc, char **argv)
 173 {
 174   g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Load module %s explicitly", name);
 175   LttvModule *m = module_load(name, argc, argv);
 176   if(m != NULL) m->load_count++;
 177   return m;
 178 }
 179
 180
 181 LttvModule *
 182 lttv_module_require(LttvModule *m, const char *name, int argc, char **argv)
 183 {
 184   LttvModule *module;
 185
 186   g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO,
 187       "Load module %s, as %s is a dependent requiring it", name,
 188       g_module_name(m->module));
 189   module = module_load(name, argc, argv);
 190   if(module != NULL) g_ptr_array_add(m->dependents, module);
 191   return module;
 192 }
 193
 194
 195 static void module_unload(LttvModule *m)
 196 {
 197   LttvModuleDestroy destroy_function;
 198
 199   char *pathname;
 200
 201   guint i, len;
 202
 203   /* Decrement the reference count */
 204
 205   g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload module %s",
 206       g_module_name(m->module));
 207   m->ref_count--;
 208   if(m->ref_count > 0) {
 209     g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,
 210         "Module usage count decremented to %d", m->ref_count);
 211     return;
 212   }
 213
 214   /* We really have to unload the module. First destroy it. */
 215
 216   g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,
 217       "Call the destroy function and unload the module");
 218   if(!g_module_symbol(m->module, "destroy", (gpointer)&destroy_function)) {
 219     g_warning("module (%s) has no destroy function", pathname);
 220   }
 221   else destroy_function();
 222
 223   /* Then release the modules required by this module */
 224
 225   len = m->dependents->len;
 226   g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload dependent modules");
 227
 228   for(i = 0 ; i < len ; i++) {
 229     module_unload(m->dependents->pdata[i]);
 230   }
 231
 232   if(len != m->dependents->len) g_error("dependents list modified");
 233
 234   /* Finally remove any trace of this module */
 235
 236   g_hash_table_remove(modules, g_module_name(m->module));
 237   g_ptr_array_free(m->dependents, TRUE);
 238   g_module_close(m->module);
 239   g_free(m);
 240 }
 241
 242
 243 void lttv_module_unload(LttvModule *m)
 244 {
 245   g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Explicitly unload module %s",
 246       g_module_name(m->module));
 247   if(m->load_count <= 0) {
 248     g_error("more unload than load (%s)", g_module_name(m->module));
 249     return;
 250   }
 251   m->load_count--;
 252   module_unload(m);
 253 }
 254
 255
 256 static void
 257 list_modules(gpointer key, gpointer value, gpointer user_data)
 258 {
 259   g_ptr_array_add((GPtrArray *)user_data, value);
 260 }
 261
 262
 263 LttvModule **
 264 lttv_module_list(guint *nb)
 265 {
 266   GPtrArray *list = g_ptr_array_new();
 267
 268   LttvModule **array;
 269
 270   g_hash_table_foreach(modules, list_modules, list);
 271   *nb = list->len;
 272   array = (LttvModule **)list->pdata;
 273   g_ptr_array_free(list, FALSE);
 274   return array;
 275 }
 276
 277
 278 LttvModule **
 279 lttv_module_info(LttvModule *m, const char **name,
 280     guint *ref_count, guint *load_count, guint *nb_dependents)
 281 {
 282   guint i, len = m->dependents->len;
 283
 284   LttvModule **array = g_new(LttvModule *, len);
 285
 286   *name = g_module_name(m->module);
 287   *ref_count = m->ref_count;
 288   *load_count = m->load_count;
 289   *nb_dependents = len;
 290   for(i = 0 ; i < len ; i++) array[i] = m->dependents->pdata[i];
 291   return array;
 292 }
 293
 294 char *
 295 lttv_module_name(LttvModule *m)
 296 {
 297   return g_module_name(m->module);
 298 }
 299
 300 static void
 301 list_independent(gpointer key, gpointer value, gpointer user_data)
 302 {
 303   LttvModule *m = (LttvModule *)value;
 304
 305   if(m->load_count > 0) g_ptr_array_add((GPtrArray *)user_data, m);
 306 }
 307
 308
 309 void
 310 lttv_module_unload_all()
 311 {
 312   guint i;
 313
 314   LttvModule *m;
 315
 316   GPtrArray *independent_modules;
 317
 318   while(g_hash_table_size(modules) != 0) {
 319     independent_modules = g_ptr_array_new();
 320     g_hash_table_foreach(modules, list_independent, independent_modules);
 321
 322     for(i = 0 ; i < independent_modules->len ; i++) {
 323       m = (LttvModule *)independent_modules->pdata[i];
 324       lttv_module_unload(m);
 325     }
 326     g_ptr_array_free(independent_modules, TRUE);
 327   }
 328 }