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 SIMIX_pre_mc_snapshot(smx_simcall_t simcall){
 175   return MC_take_snapshot();
 176 }
 177
 178 mc_snapshot_t MC_take_snapshot()
 179 {
 180
 181   int raw_mem = (mmalloc_get_current_heap() == raw_heap);
 182
 183   MC_SET_RAW_MEM;
 184
 185   mc_snapshot_t snapshot = xbt_new0(s_mc_snapshot_t, 1);
 186
 187   unsigned int i = 0;
 188   s_map_region_t reg;
 189   memory_map_t maps = get_memory_map();
 190   int nb_reg = 0;
 191   void *heap = NULL;
 192
 193   /* Save the std heap and the writable mapped pages of libsimgrid */
 194   while (i < maps->mapsize) {
 195     reg = maps->regions[i];
 196     if ((reg.prot & PROT_WRITE)){
 197       if (maps->regions[i].pathname == NULL){
 198         if (reg.start_addr == std_heap){ // only save the std heap (and not the raw one)
 199           MC_snapshot_add_region(snapshot, 0, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
 200           heap = snapshot->regions[nb_reg]->data;
 201           nb_reg++;
 202         }else if(reg.start_addr == raw_heap){
 203           end_raw_heap = reg.end_addr;
 204         }
 205         i++;
 206       } else {
 207         if (!memcmp(basename(maps->regions[i].pathname), "libsimgrid", 10)){
 208           MC_snapshot_add_region(snapshot, 1, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
 209           start_data_libsimgrid = reg.start_addr;
 210           nb_reg++;
 211           i++;
 212           reg = maps->regions[i];
 213           if(reg.pathname == NULL && (reg.prot & PROT_WRITE) && i < maps->mapsize){
 214             MC_snapshot_add_region(snapshot, 1, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
 215             reg = maps->regions[i];
 216             i++;
 217             nb_reg++;
 218           }
 219         } else {
 220           if (!memcmp(basename(maps->regions[i].pathname), basename(xbt_binary_name), strlen(basename(xbt_binary_name)))){
 221             MC_snapshot_add_region(snapshot, 2, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
 222             nb_reg++;
 223             i++;
 224             reg = maps->regions[i];
 225             if(reg.pathname == NULL && (reg.prot & PROT_WRITE) && reg.start_addr != std_heap && reg.start_addr != raw_heap && i < maps->mapsize){
 226               MC_snapshot_add_region(snapshot, 2, reg.start_addr, (char*)reg.end_addr - (char*)reg.start_addr);
 227               reg = maps->regions[i];
 228               nb_reg++;
 229             }
 230           }else{
 231             i++;
 232           }
 233         }
 234       }
 235     }else if ((reg.prot & PROT_READ)){
 236       if (maps->regions[i].pathname != NULL){
 237         if (!memcmp(basename(maps->regions[i].pathname), "libsimgrid", 10)){
 238           start_text_libsimgrid = reg.start_addr;
 239           libsimgrid_path = strdup(maps->regions[i].pathname);
 240         }else{
 241           if (!memcmp(basename(maps->regions[i].pathname), basename(xbt_binary_name), strlen(basename(xbt_binary_name)))){
 242             start_text_binary = reg.start_addr;
 243           }
 244         }
 245       }
 246       i++;
 247     }else{
 248       i++;
 249     }
 250   }
 251
 252   if(_surf_mc_visited > 0 || strcmp(_surf_mc_property_file,""))
 253     snapshot->stacks = take_snapshot_stacks(heap);
 254
 255   free_memory_map(maps);
 256
 257   MC_UNSET_RAW_MEM;
 258
 259   if(raw_mem)
 260     MC_SET_RAW_MEM;
 261
 262   return snapshot;
 263
 264 }
 265
 266 void MC_restore_snapshot(mc_snapshot_t snapshot)
 267 {
 268   unsigned int i;
 269   for(i=0; i < snapshot->num_reg; i++){
 270     MC_region_restore(snapshot->regions[i]);
 271   }
 272
 273 }
 274
 275 void MC_free_snapshot(mc_snapshot_t snapshot)
 276 {
 277   unsigned int i;
 278   for(i=0; i < snapshot->num_reg; i++)
 279     MC_region_destroy(snapshot->regions[i]);
 280
 281   xbt_dynar_free(&(snapshot->stacks));
 282   xbt_free(snapshot);
 283 }
 284
 285
 286 void get_libsimgrid_plt_section(){
 287
 288   FILE *fp;
 289   char *line = NULL;            /* Temporal storage for each line that is readed */
 290   ssize_t read;                 /* Number of bytes readed */
 291   size_t n = 0;                 /* Amount of bytes to read by getline */
 292
 293   char *lfields[7];
 294   int i, plt_not_found = 1;
 295   unsigned long int size, offset;
 296
 297   if(libsimgrid_path == NULL)
 298     libsimgrid_path = get_libsimgrid_path();
 299
 300   char *command = bprintf("objdump --section-headers %s", libsimgrid_path);
 301
 302   fp = popen(command, "r");
 303
 304   if(fp == NULL){
 305     perror("popen failed");
 306     xbt_abort();
 307   }
 308
 309   while ((read = getline(&line, &n, fp)) != -1 && plt_not_found == 1) {
 310
 311     if(n == 0)
 312       continue;
 313
 314     /* Wipeout the new line character */
 315     line[read - 1] = '\0';
 316
 317     lfields[0] = strtok(line, " ");
 318
 319     if(lfields[0] == NULL)
 320       continue;
 321
 322     if(strcmp(lfields[0], "Sections:") == 0 || strcmp(lfields[0], "Idx") == 0 || strncmp(lfields[0], libsimgrid_path, strlen(libsimgrid_path)) == 0)
 323       continue;
 324
 325     for (i = 1; i < 7 && lfields[i - 1] != NULL; i++) {
 326       lfields[i] = strtok(NULL, " ");
 327     }
 328
 329     if(i>=6){
 330       if(strcmp(lfields[1], ".plt") == 0){
 331         size = strtoul(lfields[2], NULL, 16);
 332         offset = strtoul(lfields[5], NULL, 16);
 333         start_plt_libsimgrid = (char *)start_text_libsimgrid + offset;
 334         end_plt_libsimgrid = (char *)start_plt_libsimgrid + size;
 335         plt_not_found = 0;
 336       }
 337     }
 338
 339   }
 340
 341   free(command);
 342   free(line);
 343   pclose(fp);
 344
 345 }
 346
 347 void get_binary_plt_section(){
 348
 349   FILE *fp;
 350   char *line = NULL;            /* Temporal storage for each line that is readed */
 351   ssize_t read;                 /* Number of bytes readed */
 352   size_t n = 0;                 /* Amount of bytes to read by getline */
 353
 354   char *lfields[7];
 355   int i, plt_not_found = 1;
 356   unsigned long int size, offset;
 357
 358   char *command = bprintf( "objdump --section-headers %s", xbt_binary_name);
 359
 360   fp = popen(command, "r");
 361
 362   if(fp == NULL){
 363     perror("popen failed");
 364     xbt_abort();
 365   }
 366
 367   while ((read = getline(&line, &n, fp)) != -1 && plt_not_found == 1) {
 368
 369     if(n == 0)
 370       continue;
 371
 372     /* Wipeout the new line character */
 373     line[read - 1] = '\0';
 374
 375     lfields[0] = strtok(line, " ");
 376
 377     if(lfields[0] == NULL)
 378       continue;
 379
 380     if(strcmp(lfields[0], "Sections:") == 0 || strcmp(lfields[0], "Idx") == 0 || strncmp(lfields[0], basename(xbt_binary_name), strlen(xbt_binary_name)) == 0)
 381       continue;
 382
 383     for (i = 1; i < 7 && lfields[i - 1] != NULL; i++) {
 384       lfields[i] = strtok(NULL, " ");
 385     }
 386
 387     if(i>=6){
 388       if(strcmp(lfields[1], ".plt") == 0){
 389         size = strtoul(lfields[2], NULL, 16);
 390         offset = strtoul(lfields[5], NULL, 16);
 391         start_plt_binary = (char *)start_text_binary + offset;
 392         end_plt_binary = (char *)start_plt_binary + size;
 393         plt_not_found = 0;
 394       }
 395     }
 396
 397
 398   }
 399
 400   free(command);
 401   free(line);
 402   pclose(fp);
 403
 404 }
 405
 406 static void add_value(xbt_dynar_t *list, const char *type, unsigned long int val){
 407   variable_value_t value = xbt_new0(s_variable_value_t, 1);
 408   value->type = strdup(type);
 409   if(strcmp(type, "value") == 0){
 410     value->value.res = val;
 411   }else{
 412     value->value.address = (void *)val;
 413   }
 414   xbt_dynar_push(*list, &value);
 415 }
 416
 417 static xbt_dynar_t take_snapshot_stacks(void *heap){
 418
 419   xbt_dynar_t res = xbt_dynar_new(sizeof(s_mc_snapshot_stack_t), NULL);
 420
 421   unsigned int cursor1 = 0;
 422   stack_region_t current_stack;
 423
 424   xbt_dynar_foreach(stacks_areas, cursor1, current_stack){
 425     mc_snapshot_stack_t st = xbt_new(s_mc_snapshot_stack_t, 1);
 426     st->local_variables = get_local_variables_values(current_stack->context, heap);
 427     st->stack_pointer = get_stack_pointer(current_stack->context, heap);
 428     xbt_dynar_push(res, &st);
 429   }
 430
 431   return res;
 432
 433 }
 434
 435 static void *get_stack_pointer(void *stack_context, void *heap){
 436
 437   unw_cursor_t c;
 438   int ret;
 439   unw_word_t sp;
 440
 441   ret = unw_init_local(&c, (unw_context_t *)stack_context);
 442   if(ret < 0){
 443     XBT_INFO("unw_init_local failed");
 444     xbt_abort();
 445   }
 446
 447   unw_get_reg(&c, UNW_REG_SP, &sp);
 448
 449   return ((char *)heap + (size_t)(((char *)((long)sp) - (char*)std_heap)));
 450
 451 }
 452
 453 static xbt_strbuff_t get_local_variables_values(void *stack_context, void *heap){
 454
 455   unw_cursor_t c;
 456   int ret;
 457   //char *stack_name;
 458
 459   char frame_name[256];
 460
 461   ret = unw_init_local(&c, (unw_context_t *)stack_context);
 462   if(ret < 0){
 463     XBT_INFO("unw_init_local failed");
 464     xbt_abort();
 465   }
 466
 467   //stack_name = strdup(((smx_process_t)((smx_ctx_sysv_t)(stack->address))->super.data)->name);
 468
 469   unw_word_t ip, sp, off;
 470   dw_frame_t frame;
 471
 472   xbt_dynar_t compose = xbt_dynar_new(sizeof(variable_value_t), NULL);
 473
 474   xbt_strbuff_t variables = xbt_strbuff_new();
 475   xbt_dict_cursor_t dict_cursor;
 476   char *variable_name;
 477   dw_local_variable_t current_variable;
 478   unsigned int cursor = 0, cursor2 = 0;
 479   dw_location_entry_t entry = NULL;
 480   dw_location_t location_entry = NULL;
 481   unw_word_t res;
 482   int frame_found = 0;
 483   void *frame_pointer_address = NULL;
 484   long true_ip;
 485
 486   while(ret >= 0){
 487
 488     unw_get_reg(&c, UNW_REG_IP, &ip);
 489     unw_get_reg(&c, UNW_REG_SP, &sp);
 490
 491     unw_get_proc_name (&c, frame_name, sizeof (frame_name), &off);
 492
 493     xbt_strbuff_append(variables, bprintf("ip=%s\n", frame_name));
 494
 495     frame = xbt_dict_get_or_null(mc_local_variables, frame_name);
 496
 497     if(frame == NULL){
 498       ret = unw_step(&c);
 499       continue;
 500     }
 501
 502     true_ip = (long)frame->low_pc + (long)off;
 503
 504     /* Get frame pointer */
 505     switch(frame->frame_base->type){
 506     case e_dw_loclist:
 507       while((cursor < xbt_dynar_length(frame->frame_base->location.loclist)) && frame_found == 0){
 508         entry = xbt_dynar_get_as(frame->frame_base->location.loclist, cursor, dw_location_entry_t);
 509         if((true_ip >= entry->lowpc) && (true_ip < entry->highpc)){
 510           frame_found = 1;
 511           switch(entry->location->type){
 512           case e_dw_compose:
 513             xbt_dynar_reset(compose);
 514             cursor2 = 0;
 515             while(cursor2 < xbt_dynar_length(entry->location->location.compose)){
 516               location_entry = xbt_dynar_get_as(entry->location->location.compose, cursor2, dw_location_t);
 517               switch(location_entry->type){
 518               case e_dw_register:
 519                 unw_get_reg(&c, location_entry->location.reg, &res);
 520                 add_value(&compose, "address", (long)res);
 521                 break;
 522               case e_dw_bregister_op:
 523                 unw_get_reg(&c, location_entry->location.breg_op.reg, &res);
 524                 add_value(&compose, "address", (long)res + location_entry->location.breg_op.offset);
 525                 break;
 526               default:
 527                 xbt_dynar_reset(compose);
 528                 break;
 529               }
 530               cursor2++;
 531             }
 532
 533             if(xbt_dynar_length(compose) > 0){
 534               frame_pointer_address = xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1, variable_value_t)->value.address ;
 535             }
 536             break;
 537           default :
 538             frame_pointer_address = NULL;
 539             break;
 540           }
 541         }
 542         cursor++;
 543       }
 544       break;
 545     default :
 546       frame_pointer_address = NULL;
 547       break;
 548     }
 549
 550     frame_found = 0;
 551     cursor = 0;
 552
 553     //XBT_INFO("Frame %s", frame->name);
 554
 555     xbt_dict_foreach(frame->variables, dict_cursor, variable_name, current_variable){
 556       if(current_variable->location != NULL){
 557         switch(current_variable->location->type){
 558         case e_dw_compose:
 559           xbt_dynar_reset(compose);
 560           cursor = 0;
 561           while(cursor < xbt_dynar_length(current_variable->location->location.compose)){
 562             location_entry = xbt_dynar_get_as(current_variable->location->location.compose, cursor, dw_location_t);
 563             switch(location_entry->type){
 564             case e_dw_register:
 565               unw_get_reg(&c, location_entry->location.reg, &res);
 566               add_value(&compose, "value", (long)res);
 567               break;
 568             case e_dw_bregister_op:
 569               unw_get_reg(&c, location_entry->location.breg_op.reg, &res);
 570               add_value(&compose, "address", (long)res + location_entry->location.breg_op.offset);
 571               break;
 572             case e_dw_fbregister_op:
 573               if(frame_pointer_address != NULL)
 574                 add_value(&compose, "address", (long)((char *)frame_pointer_address + location_entry->location.fbreg_op));
 575               break;
 576             default:
 577               xbt_dynar_reset(compose);
 578               break;
 579             }
 580             cursor++;
 581           }
 582
 583           if(xbt_dynar_length(compose) > 0){
 584             //XBT_INFO("Variable : %s", current_variable->name);
 585             if(strcmp(xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1, variable_value_t)->type, "value") == 0){
 586               //XBT_INFO("Variable : %s - value : %lx", current_variable->name, xbt_dynar_get_as(compose, xbt_dynar_length(compose) - 1, variable_value_t)->value.res);
 587               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));
 588             }else{
 589               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){
 590                 //XBT_INFO("Variable : %s - address : NULL", current_variable->name);
 591                 xbt_strbuff_append(variables, bprintf("%s=NULL\n", current_variable->name));
 592               }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)){
 593                 //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));
 594                 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)));
 595               }else{
 596                 //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));
 597                 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)));
 598               }
 599             }
 600           }else{
 601             //XBT_INFO("Variable %s undefined", current_variable->name);
 602             xbt_strbuff_append(variables, bprintf("%s=undefined\n", current_variable->name));
 603           }
 604           break;
 605         default :
 606           break;
 607         }
 608       }else{
 609         //XBT_INFO("Variable : %s, no location", current_variable->name);
 610         xbt_strbuff_append(variables, bprintf("%s=undefined\n", current_variable->name));
 611       }
 612     }
 613
 614     ret = unw_step(&c);
 615
 616     //XBT_INFO(" ");
 617
 618   }
 619
 620   //free(stack_name);
 621
 622   return variables;
 623
 624 }
 625
 626 static void print_local_variables_values(xbt_dynar_t all_variables){
 627
 628   unsigned cursor = 0;
 629   mc_snapshot_stack_t stack;
 630
 631   xbt_dynar_foreach(all_variables, cursor, stack){
 632     XBT_INFO("%s", stack->local_variables->data);
 633   }
 634 }
 635
 636
 637 static void snapshot_stack_free(mc_snapshot_stack_t s){
 638   if(s){
 639     xbt_free(s->local_variables->data);
 640     xbt_free(s->local_variables);
 641     xbt_free(s);
 642   }
 643 }
 644
 645 void snapshot_stack_free_voidp(void *s){
 646   snapshot_stack_free((mc_snapshot_stack_t) * (void **) s);
 647 }
 648
 649 void *MC_snapshot(void){
 650
 651   return simcall_mc_snapshot();
 652
 653 }