src/mc/mc_checkpoint.c

   1 /* Copyright (c) 2008-2012 Da SimGrid Team. All rights reserved.            */
   2
   3 /* This program is free software; you can redistribute it and/or modify it
   4  * under the terms of the license (GNU LGPL) which comes with this package. */
   5
   6 #include <libgen.h>
   7 #include "mc_private.h"
   8 #include "xbt/module.h"
   9
  10 #include "../simix/smx_private.h"
  11
  12 #include <libunwind.h>
  13
  14 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_checkpoint, mc,
  15                                 "Logging specific to mc_checkpoint");
  16
  17 void *start_text_libsimgrid;
  18 void *start_plt_libsimgrid, *end_plt_libsimgrid;
  19 void *start_plt_binary, *end_plt_binary;
  20 char *libsimgrid_path;
  21 void *start_data_libsimgrid, *start_bss_libsimgrid;
  22 void *start_data_binary, *start_bss_binary;
  23 void *start_text_binary;
  24 void *end_raw_heap;
  25
  26 static mc_mem_region_t MC_region_new(int type, void *start_addr, size_t size);
  27 static void MC_region_restore(mc_mem_region_t reg);
  28 static void MC_region_destroy(mc_mem_region_t reg);
  29
  30 static void MC_snapshot_add_region(mc_snapshot_t snapshot, int type, void *start_addr, size_t size);
  31
  32 static void add_value(xbt_dynar_t *list, const char *type, unsigned long int val);
  33 static xbt_dynar_t take_snapshot_stacks(void *heap);
  34 static xbt_strbuff_t get_local_variables_values(void *stack_context, void *heap);
  35 static void print_local_variables_values(xbt_dynar_t all_variables);
  36 static void *get_stack_pointer(void *stack_context, void *heap);
  37
  38 static void snapshot_stack_free(mc_snapshot_stack_t s);
  39
  40 static mc_mem_region_t MC_region_new(int type, void *start_addr, size_t size)
  41 {
  42   mc_mem_region_t new_reg = xbt_new0(s_mc_mem_region_t, 1);
  43   new_reg->type = type;
  44   new_reg->start_addr = start_addr;
  45   new_reg->size = size;
  46   new_reg->data = xbt_malloc0(size);
  47   memcpy(new_reg->data, start_addr, size);
  48
  49   XBT_DEBUG("New region : type : %d, data : %p, size : %zu", type, new_reg->data, size);
  50
  51   return new_reg;
  52 }
  53
  54 static void MC_region_restore(mc_mem_region_t reg)
  55 {
  56   /*FIXME: check if start_addr is still mapped, if it is not, then map it
  57     before copying the data */
  58
  59   memcpy(reg->start_addr, reg->data, reg->size);
  60
  61   return;
  62 }
  63
  64 static void MC_region_destroy(mc_mem_region_t reg)
  65 {
  66   xbt_free(reg->data);
  67   xbt_free(reg);
  68 }
  69
  70 static void MC_snapshot_add_region(mc_snapshot_t snapshot, int type, void *start_addr, size_t size)
  71 {
  72   mc_mem_region_t new_reg = MC_region_new(type, start_addr, size);
  73   snapshot->regions = xbt_realloc(snapshot->regions, (snapshot->num_reg + 1) * sizeof(mc_mem_region_t));
  74   snapshot->regions[snapshot->num_reg] = new_reg;
  75   snapshot->num_reg++;
  76   return;
  77 }
  78
  79 /* void MC_take_snapshot(mc_snapshot_t snapshot) */
  80 /* { */
  81 /*   unsigned int i = 0; */
  82 /*   s_map_region_t reg; */
  83 /*   memory_map_t maps = get_memory_map(); */
  84
  85 /*   /\* Save the std heap and the writable mapped pages of libsimgrid *\/ */
  86 /*   while (i < maps->mapsize) { */
  87 /*     reg = maps->regions[i]; */
  88 /*     if ((reg.prot & PROT_WRITE)){ */
  89 /*       if (maps->regions[i].pathname == NULL){ */
  90 /*         if (reg.start_addr == std_heap){ // only save the std heap (and not the raw one) */
  91 /*           MC_snapshot_add_region(snapshot, 0, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr); */
  92 /*         } */
  93 /*         i++; */
  94 /*       } else { */
  95 /*         if (!memcmp(basename(maps->regions[i].pathname), "libsimgrid", 10)){ */
  96 /*           MC_snapshot_add_region(snapshot, 1, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr); */
  97 /*           i++; */
  98 /*           reg = maps->regions[i]; */
  99 /*           while(reg.pathname == NULL && (reg.prot & PROT_WRITE) && i < maps->mapsize){ */
 100 /*             MC_snapshot_add_region(snapshot, 1, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr); */
 101 /*             i++; */
 102 /*             reg = maps->regions[i]; */
 103 /*           } */
 104 /*         }else{ */
 105 /*           i++; */
 106 /*         }  */
 107 /*       } */
 108 /*     }else{ */
 109 /*       i++; */
 110 /*     } */
 111 /*   } */
 112
 113 /*   free_memory_map(maps); */
 114 /* } */
 115
 116 void MC_init_memory_map_info(){
 117
 118   int raw_mem_set = (mmalloc_get_current_heap() == raw_heap);
 119
 120   MC_SET_RAW_MEM;
 121
 122   unsigned int i = 0;
 123   s_map_region_t reg;
 124   memory_map_t maps = get_memory_map();
 125
 126   while (i < maps->mapsize) {
 127     reg = maps->regions[i];
 128     if ((reg.prot & PROT_WRITE)){
 129       if (maps->regions[i].pathname == NULL){
 130         if(reg.start_addr == raw_heap){
 131           end_raw_heap = reg.end_addr;
 132         }
 133       } else {
 134         if (!memcmp(basename(maps->regions[i].pathname), "libsimgrid", 10)){
 135           start_data_libsimgrid = reg.start_addr;
 136           i++;
 137           reg = maps->regions[i];
 138           if(reg.pathname == NULL && (reg.prot & PROT_WRITE) && i < maps->mapsize)
 139             start_bss_libsimgrid = reg.start_addr;
 140         }else if (!memcmp(basename(maps->regions[i].pathname), basename(xbt_binary_name), strlen(basename(xbt_binary_name)))){
 141           start_data_binary = reg.start_addr;
 142           i++;
 143           reg = maps->regions[i];
 144           if(reg.pathname == NULL && (reg.prot & PROT_WRITE) && reg.start_addr != std_heap && reg.start_addr != raw_heap && i < maps->mapsize){
 145             start_bss_binary = reg.start_addr;
 146             i++;
 147           }
 148         }
 149       }
 150     }else if ((reg.prot & PROT_READ)){
 151       if (maps->regions[i].pathname != NULL){
 152         if (!memcmp(basename(maps->regions[i].pathname), "libsimgrid", 10)){
 153           start_text_libsimgrid = reg.start_addr;
 154           libsimgrid_path = strdup(maps->regions[i].pathname);
 155         }else{
 156           if (!memcmp(basename(maps->regions[i].pathname), basename(xbt_binary_name), strlen(basename(xbt_binary_name)))){
 157             start_text_binary = reg.start_addr;
 158           }
 159         }
 160       }
 161     }
 162     i++;
 163   }
 164
 165   free_memory_map(maps);
 166
 167   MC_UNSET_RAW_MEM;
 168
 169   if(raw_mem_set)
 170     MC_SET_RAW_MEM;
 171
 172 }
 173
 174 mc_snapshot_t MC_take_snapshot()
 175 {
 176
 177   int raw_mem = (mmalloc_get_current_heap() == raw_heap);
 178
 179   MC_SET_RAW_MEM;
 180
 181   mc_snapshot_t snapshot = xbt_new0(s_mc_snapshot_t, 1);
 182
 183   unsigned int i = 0;
 184   s_map_region_t reg;
 185   memory_map_t maps = get_memory_map();
 186   int nb_reg = 0;
 187   void *heap = NULL;
 188
 189   /* Save the std heap and the writable mapped pages of libsimgrid */
 190   while (i < maps->mapsize) {
 191     reg = maps->regions[i];
 192     if ((reg.prot & PROT_WRITE)){
 193       if (maps->regions[i].pathname == NULL){
 194         if (reg.start_addr == std_heap){ // only save the std heap (and not the raw one)
 195           MC_snapshot_add_region(snapshot, 0, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
 196           heap = snapshot->regions[nb_reg]->data;
 197           nb_reg++;
 198         }else if(reg.start_addr == raw_heap){
 199           end_raw_heap = reg.end_addr;
 200         }
 201         i++;
 202       } else {
 203         if (!memcmp(basename(maps->regions[i].pathname), "libsimgrid", 10)){
 204           MC_snapshot_add_region(snapshot, 1, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
 205           start_data_libsimgrid = reg.start_addr;
 206           nb_reg++;
 207           i++;
 208           reg = maps->regions[i];
 209           if(reg.pathname == NULL && (reg.prot & PROT_WRITE) && i < maps->mapsize){
 210             MC_snapshot_add_region(snapshot, 1, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
 211             reg = maps->regions[i];
 212             i++;
 213             nb_reg++;
 214           }
 215         } else {
 216           if (!memcmp(basename(maps->regions[i].pathname), basename(xbt_binary_name), strlen(basename(xbt_binary_name)))){
 217             MC_snapshot_add_region(snapshot, 2, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
 218             nb_reg++;
 219             i++;
 220             reg = maps->regions[i];
 221             if(reg.pathname == NULL && (reg.prot & PROT_WRITE) && reg.start_addr != std_heap && reg.start_addr != raw_heap && i < maps->mapsize){
 222               MC_snapshot_add_region(snapshot, 2, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
 223               reg = maps->regions[i];
 224               nb_reg++;
 225             }
 226           }else{
 227             i++;
 228           }
 229         }
 230       }
 231     }else if ((reg.prot & PROT_READ)){
 232       if (maps->regions[i].pathname != NULL){
 233         if (!memcmp(basename(maps->regions[i].pathname), "libsimgrid", 10)){
 234           start_text_libsimgrid = reg.start_addr;
 235           libsimgrid_path = strdup(maps->regions[i].pathname);
 236         }else{
 237           if (!memcmp(basename(maps->regions[i].pathname), basename(xbt_binary_name), strlen(basename(xbt_binary_name)))){
 238             start_text_binary = reg.start_addr;
 239           }
 240         }
 241       }
 242       i++;
 243     }else{
 244       i++;
 245     }
 246   }
 247
 248   snapshot->stacks = take_snapshot_stacks(heap);
 249
 250   free_memory_map(maps);
 251
 252   MC_UNSET_RAW_MEM;
 253
 254   if(raw_mem)
 255     MC_SET_RAW_MEM;
 256
 257   return snapshot;
 258
 259 }
 260
 261 void MC_restore_snapshot(mc_snapshot_t snapshot)
 262 {
 263   unsigned int i;
 264   for(i=0; i < snapshot->num_reg; i++){
 265     MC_region_restore(snapshot->regions[i]);
 266   }
 267
 268 }
 269
 270 void MC_free_snapshot(mc_snapshot_t snapshot)
 271 {
 272   unsigned int i;
 273   for(i=0; i < snapshot->num_reg; i++)
 274     MC_region_destroy(snapshot->regions[i]);
 275
 276   xbt_dynar_free(&(snapshot->stacks));
 277   xbt_free(snapshot);
 278 }
 279
 280
 281 void get_libsimgrid_plt_section(){
 282
 283   FILE *fp;
 284   char *line = NULL;            /* Temporal storage for each line that is readed */
 285   ssize_t read;                 /* Number of bytes readed */
 286   size_t n = 0;                 /* Amount of bytes to read by getline */
 287
 288   char *lfields[7];
 289   int i, plt_not_found = 1;
 290   unsigned long int size, offset;
 291
 292   if(libsimgrid_path == NULL)
 293     libsimgrid_path = get_libsimgrid_path();
 294
 295   char *command = bprintf("objdump --section-headers %s", libsimgrid_path);
 296
 297   fp = popen(command, "r");
 298
 299   if(fp == NULL)
 300     perror("popen failed");
 301
 302   while ((read = getline(&line, &n, fp)) != -1 && plt_not_found == 1) {
 303
 304     if(n == 0)
 305       continue;
 306
 307     /* Wipeout the new line character */
 308     line[read - 1] = '\0';
 309
 310     lfields[0] = strtok(line, " ");
 311
 312     if(lfields[0] == NULL)
 313       continue;
 314
 315     if(strcmp(lfields[0], "Sections:") == 0 || strcmp(lfields[0], "Idx") == 0 || strncmp(lfields[0], libsimgrid_path, strlen(libsimgrid_path)) == 0)
 316       continue;
 317
 318     for (i = 1; i < 7 && lfields[i - 1] != NULL; i++) {
 319       lfields[i] = strtok(NULL, " ");
 320     }
 321
 322     if(i>=6){
 323       if(strcmp(lfields[1], ".plt") == 0){
 324         size = strtoul(lfields[2], NULL, 16);
 325         offset = strtoul(lfields[5], NULL, 16);
 326         start_plt_libsimgrid = (char *)start_text_libsimgrid + offset;
 327         end_plt_libsimgrid = (char *)start_plt_libsimgrid + size;
 328         plt_not_found = 0;
 329       }
 330     }
 331
 332   }
 333
 334   free(command);
 335   free(line);
 336   pclose(fp);
 337
 338 }
 339
 340 void get_binary_plt_section(){
 341
 342   FILE *fp;
 343   char *line = NULL;            /* Temporal storage for each line that is readed */
 344   ssize_t read;                 /* Number of bytes readed */
 345   size_t n = 0;                 /* Amount of bytes to read by getline */
 346
 347   char *lfields[7];
 348   int i, plt_not_found = 1;
 349   unsigned long int size, offset;
 350
 351   char *command = bprintf( "objdump --section-headers %s", xbt_binary_name);
 352
 353   fp = popen(command, "r");
 354
 355   if(fp == NULL)
 356     perror("popen failed");
 357
 358   while ((read = getline(&line, &n, fp)) != -1 && plt_not_found == 1) {
 359
 360     if(n == 0)
 361       continue;
 362
 363     /* Wipeout the new line character */
 364     line[read - 1] = '\0';
 365
 366     lfields[0] = strtok(line, " ");
 367
 368     if(lfields[0] == NULL)
 369       continue;
 370
 371     if(strcmp(lfields[0], "Sections:") == 0 || strcmp(lfields[0], "Idx") == 0 || strncmp(lfields[0], basename(xbt_binary_name), strlen(xbt_binary_name)) == 0)
 372       continue;
 373
 374     for (i = 1; i < 7 && lfields[i - 1] != NULL; i++) {
 375       lfields[i] = strtok(NULL, " ");
 376     }
 377
 378     if(i>=6){
 379       if(strcmp(lfields[1], ".plt") == 0){
 380         size = strtoul(lfields[2], NULL, 16);
 381         offset = strtoul(lfields[5], NULL, 16);
 382         start_plt_binary = (char *)start_text_binary + offset;
 383         end_plt_binary = (char *)start_plt_binary + size;
 384         plt_not_found = 0;
 385       }
 386     }
 387
 388
 389   }
 390
 391   free(command);
 392   free(line);
 393   pclose(fp);
 394
 395 }
 396
 397 static void add_value(xbt_dynar_t *list, const char *type, unsigned long int val){
 398   variable_value_t value = xbt_new0(s_variable_value_t, 1);
 399   value->type = strdup(type);
 400   if(strcmp(type, "value") == 0){
 401     value->value.res = val;
 402   }else{
 403     value->value.address = (void *)val;
 404   }
 405   xbt_dynar_push(*list, &value);
 406 }
 407
 408 static xbt_dynar_t take_snapshot_stacks(void *heap){
 409
 410   xbt_dynar_t res = xbt_dynar_new(sizeof(s_mc_snapshot_stack_t), NULL);
 411
 412   unsigned int cursor1 = 0;
 413   stack_region_t current_stack;
 414
 415   xbt_dynar_foreach(stacks_areas, cursor1, current_stack){
 416     mc_snapshot_stack_t st = xbt_new(s_mc_snapshot_stack_t, 1);
 417     st->local_variables = get_local_variables_values(current_stack->context, heap);
 418     st->stack_pointer = get_stack_pointer(current_stack->context, heap);
 419     xbt_dynar_push(res, &st);
 420   }
 421
 422   return res;
 423
 424 }
 425
 426 static void *get_stack_pointer(void *stack_context, void *heap){
 427
 428   unw_cursor_t c;
 429   int ret;
 430   unw_word_t sp;
 431
 432   ret = unw_init_local(&c, (unw_context_t *)stack_context);
 433   if(ret < 0){
 434     XBT_INFO("unw_init_local failed");
 435     xbt_abort();
 436   }
 437
 438   unw_get_reg(&c, UNW_REG_SP, &sp);
 439
 440   return ((char *)heap + (size_t)(((char *)((long)sp) - (char*)std_heap)));
 441
 442 }
 443
 444 static xbt_strbuff_t get_local_variables_values(void *stack_context, void *heap){
 445
 446   unw_cursor_t c;
 447   int ret;
 448   //char *stack_name;
 449
 450   char frame_name[256];
 451
 452   ret = unw_init_local(&c, (unw_context_t *)stack_context);
 453   if(ret < 0){
 454     XBT_INFO("unw_init_local failed");
 455     xbt_abort();
 456   }
 457
 458   //stack_name = strdup(((smx_process_t)((smx_ctx_sysv_t)(stack->address))->super.data)->name);
 459
 460   unw_word_t ip, sp, off;
 461   dw_frame_t frame;
 462
 463   xbt_dynar_t compose = xbt_dynar_new(sizeof(variable_value_t), NULL);
 464
 465   xbt_strbuff_t variables = xbt_strbuff_new();
 466   xbt_dict_cursor_t dict_cursor;
 467   char *variable_name;
 468   dw_local_variable_t current_variable;
 469   unsigned int cursor = 0, cursor2 = 0;
 470   dw_location_entry_t entry = NULL;
 471   dw_location_t location_entry = NULL;
 472   unw_word_t res;
 473   int frame_found = 0;
 474   void *frame_pointer_address = NULL;
 475   long true_ip;
 476
 477   while(ret >= 0){
 478
 479     unw_get_reg(&c, UNW_REG_IP, &ip);
 480     unw_get_reg(&c, UNW_REG_SP, &sp);
 481
 482     unw_get_proc_name (&c, frame_name, sizeof (frame_name), &off);
 483
 484     xbt_strbuff_append(variables, bprintf("ip=%s\n", frame_name));
 485
 486     frame = xbt_dict_get_or_null(mc_local_variables, frame_name);
 487
 488     if(frame == NULL){
 489       ret = unw_step(&c);
 490       continue;
 491     }
 492
 493     true_ip = (long)frame->low_pc + (long)off;
 494
 495     /* Get frame pointer */
 496     switch(frame->frame_base->type){
 497     case e_dw_loclist:
 498       while((cursor < xbt_dynar_length(frame->frame_base->location.loclist)) && frame_found == 0){
 499         entry = xbt_dynar_get_as(frame->frame_base->location.loclist, cursor, dw_location_entry_t);
 500         if((true_ip >= entry->lowpc) && (true_ip < entry->highpc)){
 501           frame_found = 1;
 502           switch(entry->location->type){
 503           case e_dw_compose:
 504             xbt_dynar_reset(compose);
 505             cursor2 = 0;
 506             while(cursor2 < xbt_dynar_length(entry->location->location.compose)){
 507               location_entry = xbt_dynar_get_as(entry->location->location.compose, cursor2, dw_location_t);
 508               switch(location_entry->type){
 509               case e_dw_register:
 510                 unw_get_reg(&c, location_entry->location.reg, &res);
 511                 add_value(&compose, "address", (long)res);
 512                 break;
 513               case e_dw_bregister_op:
 514                 unw_get_reg(&c, location_entry->location.breg_op.reg, &res);
 515                 add_value(&compose, "address", (long)res + location_entry->location.breg_op.offset);
 516                 break;
 517               default:
 518                 xbt_dynar_reset(compose);
 519                 break;
 520               }
 521               cursor2++;
 522             }
 523
 524             if(xbt_dynar_length(compose) > 0){
 525               frame_pointer_address = xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1, variable_value_t)->value.address ;
 526             }
 527             break;
 528           default :
 529             frame_pointer_address = NULL;
 530             break;
 531           }
 532         }
 533         cursor++;
 534       }
 535       break;
 536     default :
 537       frame_pointer_address = NULL;
 538       break;
 539     }
 540
 541     frame_found = 0;
 542     cursor = 0;
 543
 544     //XBT_INFO("Frame %s", frame->name);
 545
 546     xbt_dict_foreach(frame->variables, dict_cursor, variable_name, current_variable){
 547       if(current_variable->location != NULL){
 548         switch(current_variable->location->type){
 549         case e_dw_compose:
 550           xbt_dynar_reset(compose);
 551           cursor = 0;
 552           while(cursor < xbt_dynar_length(current_variable->location->location.compose)){
 553             location_entry = xbt_dynar_get_as(current_variable->location->location.compose, cursor, dw_location_t);
 554             switch(location_entry->type){
 555             case e_dw_register:
 556               unw_get_reg(&c, location_entry->location.reg, &res);
 557               add_value(&compose, "value", (long)res);
 558               break;
 559             case e_dw_bregister_op:
 560               unw_get_reg(&c, location_entry->location.breg_op.reg, &res);
 561               add_value(&compose, "address", (long)res + location_entry->location.breg_op.offset);
 562               break;
 563             case e_dw_fbregister_op:
 564               if(frame_pointer_address != NULL)
 565                 add_value(&compose, "address", (long)((char *)frame_pointer_address + location_entry->location.fbreg_op));
 566               break;
 567             default:
 568               xbt_dynar_reset(compose);
 569               break;
 570             }
 571             cursor++;
 572           }
 573
 574           if(xbt_dynar_length(compose) > 0){
 575             //XBT_INFO("Variable : %s", current_variable->name);
 576             if(strcmp(xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1, variable_value_t)->type, "value") == 0){
 577               //XBT_INFO("Variable : %s - value : %lx", current_variable->name, xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1, variable_value_t)->value.res);
 578               xbt_strbuff_append(variables, bprintf("%s=%lx\n", current_variable->name, xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1, variable_value_t)->value.res));
 579             }else{
 580               if((long)xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1,variable_value_t)->value.address < 0 || *((void**)xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1,variable_value_t)->value.address) == NULL){
 581                 //XBT_INFO("Variable : %s - address : NULL", current_variable->name);
 582                 xbt_strbuff_append(variables, bprintf("%s=NULL\n", current_variable->name));
 583               }else if(((long)*((void**)xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1,variable_value_t)->value.address) > 0xffffffff) || ((long)*((void**)xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1,variable_value_t)->value.address) < (long)start_text_binary)){
 584                 //XBT_INFO("Variable : %s - value : %zd", current_variable->name, (size_t)*((void**)xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1, variable_value_t)->value.address));
 585                 xbt_strbuff_append(variables, bprintf("%s=%d\n", current_variable->name, (int)(long)*((void**)xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1, variable_value_t)->value.address)));
 586               }else{
 587                 //XBT_INFO("Variable : %s - address : %p", current_variable->name, *((void**)xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1, variable_value_t)->value.address));
 588                 xbt_strbuff_append(variables, bprintf("%s=%p\n", current_variable->name, *((void**)xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1, variable_value_t)->value.address)));
 589               }
 590             }
 591           }else{
 592             //XBT_INFO("Variable %s undefined", current_variable->name);
 593             xbt_strbuff_append(variables, bprintf("%s=undefined\n", current_variable->name));
 594           }
 595           break;
 596         default :
 597           break;
 598         }
 599       }else{
 600         //XBT_INFO("Variable : %s, no location", current_variable->name);
 601         xbt_strbuff_append(variables, bprintf("%s=undefined\n", current_variable->name));
 602       }
 603     }
 604
 605     ret = unw_step(&c);
 606
 607     //XBT_INFO(" ");
 608
 609   }
 610
 611   //free(stack_name);
 612
 613   return variables;
 614
 615 }
 616
 617 static void print_local_variables_values(xbt_dynar_t all_variables){
 618
 619   unsigned cursor = 0;
 620   mc_snapshot_stack_t stack;
 621
 622   xbt_dynar_foreach(all_variables, cursor, stack){
 623     XBT_INFO("%s", stack->local_variables->data);
 624   }
 625 }
 626
 627
 628 static void snapshot_stack_free(mc_snapshot_stack_t s){
 629   if(s){
 630     xbt_free(s->local_variables->data);
 631     xbt_free(s->local_variables);
 632     xbt_free(s);
 633   }
 634 }
 635
 636 void snapshot_stack_free_voidp(void *s){
 637   snapshot_stack_free((mc_snapshot_stack_t) * (void **) s);
 638 }
 639
 640 void *MC_snapshot(void){
 641
 642   return simcall_mc_snapshot();
 643
 644 }