src/mc/mc_process.c

   1 #include <assert.h>
   2 #include <stddef.h>
   3 #include <stdbool.h>
   4 #include <stdint.h>
   5 #include <errno.h>
   6
   7 #include <sys/types.h>
   8 #include <fcntl.h>
   9 #include <unistd.h>
  10 #include <regex.h>
  11 #include <sys/mman.h> // PROT_*
  12
  13 #include <pthread.h>
  14
  15 #include <libgen.h>
  16
  17 #include <libunwind.h>
  18 #include <libunwind-ptrace.h>
  19
  20 #include <xbt/mmalloc.h>
  21
  22 #include "mc_process.h"
  23 #include "mc_object_info.h"
  24 #include "mc_address_space.h"
  25 #include "mc_unw.h"
  26 #include "mc_snapshot.h"
  27 #include "mc_ignore.h"
  28
  29 #include "simix/smx_private.h"
  30
  31 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_process, mc,
  32                                 "MC process information");
  33
  34 static void MC_process_init_memory_map_info(mc_process_t process);
  35 static void MC_process_open_memory_file(mc_process_t process);
  36
  37 // ***** Destructor callbacks
  38
  39 // ***** mc_address_space methods for mc_process
  40
  41 static mc_process_t MC_process_get_process(mc_process_t p) {
  42   return p;
  43 }
  44
  45 static const s_mc_address_space_class_t mc_process_class = {
  46   .read = (void*) &MC_process_read,
  47   .get_process = (void*) MC_process_get_process
  48 };
  49
  50 bool MC_is_process(mc_address_space_t p)
  51 {
  52   return p->address_space_class == &mc_process_class;
  53 }
  54
  55 // ***** mc_process
  56
  57 void MC_process_init(mc_process_t process, pid_t pid, int sockfd)
  58 {
  59   process->address_space.address_space_class = &mc_process_class;
  60   process->process_flags = MC_PROCESS_NO_FLAG;
  61   process->socket = sockfd;
  62   process->pid = pid;
  63   if (pid==getpid())
  64     process->process_flags |= MC_PROCESS_SELF_FLAG;
  65   process->running = true;
  66   process->status = 0;
  67   process->memory_map = MC_get_memory_map(pid);
  68   process->memory_file = -1;
  69   process->cache_flags = 0;
  70   process->heap = NULL;
  71   process->heap_info = NULL;
  72   MC_process_init_memory_map_info(process);
  73   MC_process_open_memory_file(process);
  74
  75   // Read std_heap (is a struct mdesc*):
  76   dw_variable_t std_heap_var = MC_process_find_variable_by_name(process, "std_heap");
  77   if (!std_heap_var)
  78     xbt_die("No heap information in the target process");
  79   if(!std_heap_var->address)
  80     xbt_die("No constant address for this variable");
  81   MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE,
  82     &process->heap_address, std_heap_var->address, sizeof(struct mdesc*),
  83     MC_PROCESS_INDEX_DISABLED);
  84
  85   process->smx_process_infos = mc_smx_process_info_list_new();
  86   process->smx_old_process_infos = mc_smx_process_info_list_new();
  87
  88   process->checkpoint_ignore = MC_checkpoint_ignore_new();
  89
  90   process->unw_addr_space = unw_create_addr_space(&mc_unw_accessors  , __BYTE_ORDER);
  91   if (process->process_flags & MC_PROCESS_SELF_FLAG) {
  92     process->unw_underlying_addr_space = unw_local_addr_space;
  93     process->unw_underlying_context = NULL;
  94   } else {
  95     process->unw_underlying_addr_space = unw_create_addr_space(&mc_unw_vmread_accessors, __BYTE_ORDER);
  96     process->unw_underlying_context = _UPT_create(pid);
  97   }
  98 }
  99
 100 void MC_process_clear(mc_process_t process)
 101 {
 102   process->address_space.address_space_class = NULL;
 103   process->process_flags = MC_PROCESS_NO_FLAG;
 104   process->pid = 0;
 105
 106   MC_free_memory_map(process->memory_map);
 107   process->memory_map = NULL;
 108
 109   process->maestro_stack_start = NULL;
 110   process->maestro_stack_end = NULL;
 111
 112   xbt_dynar_free(&process->checkpoint_ignore);
 113
 114   xbt_dynar_free(&process->smx_process_infos);
 115   xbt_dynar_free(&process->smx_old_process_infos);
 116
 117   size_t i;
 118   for (i=0; i!=process->object_infos_size; ++i) {
 119     MC_free_object_info(&process->object_infos[i]);
 120   }
 121   free(process->object_infos);
 122   process->object_infos = NULL;
 123   process->object_infos_size = 0;
 124   if (process->memory_file >= 0) {
 125     close(process->memory_file);
 126   }
 127
 128   if (process->unw_underlying_addr_space != unw_local_addr_space) {
 129     unw_destroy_addr_space(process->unw_underlying_addr_space);
 130     _UPT_destroy(process->unw_underlying_context);
 131   }
 132   process->unw_underlying_context = NULL;
 133   process->unw_underlying_addr_space = NULL;
 134
 135   unw_destroy_addr_space(process->unw_addr_space);
 136   process->unw_addr_space = NULL;
 137
 138   process->cache_flags = 0;
 139
 140   free(process->heap);
 141   process->heap = NULL;
 142
 143   free(process->heap_info);
 144   process->heap_info = NULL;
 145 }
 146
 147 void MC_process_refresh_heap(mc_process_t process)
 148 {
 149   assert(!MC_process_is_self(process));
 150   // Read/dereference/refresh the std_heap pointer:
 151   if (!process->heap) {
 152     xbt_mheap_t oldheap  = mmalloc_set_current_heap(mc_heap);
 153     process->heap = malloc(sizeof(struct mdesc));
 154     mmalloc_set_current_heap(oldheap);
 155   }
 156   MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE,
 157     process->heap, process->heap_address, sizeof(struct mdesc),
 158     MC_PROCESS_INDEX_DISABLED
 159     );
 160 }
 161
 162 void MC_process_refresh_malloc_info(mc_process_t process)
 163 {
 164   assert(!MC_process_is_self(process));
 165   if (!process->cache_flags & MC_PROCESS_CACHE_FLAG_HEAP)
 166     MC_process_refresh_heap(process);
 167   // Refresh process->heapinfo:
 168   size_t malloc_info_bytesize = process->heap->heaplimit * sizeof(malloc_info);
 169
 170   xbt_mheap_t heap  = mmalloc_set_current_heap(mc_heap);
 171   process->heap_info = (malloc_info*) realloc(process->heap_info,
 172     malloc_info_bytesize);
 173   mmalloc_set_current_heap(heap);
 174
 175   MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE,
 176     process->heap_info,
 177     process->heap->heapinfo, malloc_info_bytesize,
 178     MC_PROCESS_INDEX_DISABLED);
 179 }
 180
 181 /** Load the remote swag of processes into a dynar
 182  *
 183  *  @param process     MCed process
 184  *  @param target      Local dynar (to be filled with copies of `s_smx_process_t`)
 185  *  @param remote_swag Address of the process SWAG in the remote list
 186  */
 187 static void MC_process_refresh_simix_process_list(
 188   mc_process_t process,
 189   xbt_dynar_t target, xbt_swag_t remote_swag)
 190 {
 191   // swag = REMOTE(*simix_global->process_list)
 192   s_xbt_swag_t swag;
 193   MC_process_read(process, MC_PROCESS_NO_FLAG, &swag, remote_swag, sizeof(swag),
 194     MC_PROCESS_INDEX_ANY);
 195
 196   smx_process_t p;
 197   xbt_dynar_reset(target);
 198
 199   int i = 0;
 200   for (p = swag.head; p; ++i) {
 201
 202     s_mc_smx_process_info_t info;
 203     info.address = p;
 204     MC_process_read(process, MC_PROCESS_NO_FLAG,
 205       &info.copy, p, sizeof(info.copy), MC_PROCESS_INDEX_ANY);
 206     xbt_dynar_push(target, &info);
 207
 208     // Lookup next process address:
 209     p = xbt_swag_getNext(&info.copy, swag.offset);
 210   }
 211   assert(i == swag.count);
 212 }
 213
 214 void MC_process_refresh_simix_processes(mc_process_t process)
 215 {
 216   if (process->cache_flags & MC_PROCESS_CACHE_FLAG_SIMIX_PROCESSES)
 217     return;
 218
 219   xbt_mheap_t heap = mmalloc_set_current_heap(mc_heap);
 220
 221   // TODO, avoid to reload `&simix_global`, `simix_global`, `*simix_global`
 222
 223   // simix_global_p = REMOTE(simix_global);
 224   smx_global_t simix_global_p;
 225   MC_process_read_variable(process, "simix_global", &simix_global_p, sizeof(simix_global_p));
 226
 227   // simix_global = REMOTE(*simix_global)
 228   s_smx_global_t simix_global;
 229   MC_process_read(process, MC_PROCESS_NO_FLAG, &simix_global, simix_global_p, sizeof(simix_global),
 230     MC_PROCESS_INDEX_ANY);
 231
 232   MC_process_refresh_simix_process_list(
 233     process, process->smx_process_infos, simix_global.process_list);
 234   MC_process_refresh_simix_process_list(
 235     process, process->smx_old_process_infos, simix_global.process_to_destroy);
 236
 237   process->cache_flags |= MC_PROCESS_CACHE_FLAG_SIMIX_PROCESSES;
 238   mmalloc_set_current_heap(heap);
 239 }
 240
 241 #define SO_RE "\\.so[\\.0-9]*$"
 242 #define VERSION_RE "-[\\.0-9]*$"
 243
 244 const char* FILTERED_LIBS[] = {
 245   "libstdc++",
 246   "libc++",
 247   "libm",
 248   "libgcc_s",
 249   "libpthread",
 250   "libunwind",
 251   "libunwind-x86_64",
 252   "libunwind-x86",
 253   "libunwind-ptrace",
 254   "libdw",
 255   "libdl",
 256   "librt",
 257   "liblzma",
 258   "libelf",
 259   "libbz2",
 260   "libz",
 261   "libelf",
 262   "libc",
 263   "ld"
 264 };
 265
 266 static bool MC_is_simgrid_lib(const char* libname)
 267 {
 268   return !strcmp(libname, "libsimgrid");
 269 }
 270
 271 static bool MC_is_filtered_lib(const char* libname)
 272 {
 273   const size_t n = sizeof(FILTERED_LIBS) / sizeof(const char*);
 274   size_t i;
 275   for (i=0; i!=n; ++i)
 276     if (strcmp(libname, FILTERED_LIBS[i])==0)
 277       return true;
 278   return false;
 279 }
 280
 281 struct s_mc_memory_map_re {
 282   regex_t so_re;
 283   regex_t version_re;
 284 };
 285
 286 static char* MC_get_lib_name(const char* pathname, struct s_mc_memory_map_re* res) {
 287   const char* map_basename = basename((char*) pathname);
 288
 289   regmatch_t match;
 290   if(regexec(&res->so_re, map_basename, 1, &match, 0))
 291     return NULL;
 292
 293   char* libname = strndup(map_basename, match.rm_so);
 294
 295   // Strip the version suffix:
 296   if(libname && !regexec(&res->version_re, libname, 1, &match, 0)) {
 297     char* temp = libname;
 298     libname = strndup(temp, match.rm_so);
 299     free(temp);
 300   }
 301
 302   return libname;
 303 }
 304
 305 /** @brief Finds the range of the different memory segments and binary paths */
 306 static void MC_process_init_memory_map_info(mc_process_t process)
 307 {
 308   XBT_DEBUG("Get debug information ...");
 309   process->maestro_stack_start = NULL;
 310   process->maestro_stack_end = NULL;
 311   process->object_infos = NULL;
 312   process->object_infos_size = 0;
 313   process->binary_info = NULL;
 314   process->libsimgrid_info = NULL;
 315
 316   struct s_mc_memory_map_re res;
 317
 318   if(regcomp(&res.so_re, SO_RE, 0) || regcomp(&res.version_re, VERSION_RE, 0))
 319     xbt_die(".so regexp did not compile");
 320
 321   memory_map_t maps = process->memory_map;
 322
 323   const char* current_name = NULL;
 324
 325   size_t i = 0;
 326   for (i=0; i < maps->mapsize; i++) {
 327     map_region_t reg = &(maps->regions[i]);
 328     const char* pathname = maps->regions[i].pathname;
 329
 330     // Nothing to do
 331     if (maps->regions[i].pathname == NULL) {
 332       current_name = NULL;
 333       continue;
 334     }
 335
 336     // [stack], [vvar], [vsyscall], [vdso] ...
 337     if (pathname[0] == '[') {
 338       if ((reg->prot & PROT_WRITE) && !memcmp(pathname, "[stack]", 7)) {
 339         process->maestro_stack_start = reg->start_addr;
 340         process->maestro_stack_end = reg->end_addr;
 341       }
 342       current_name = NULL;
 343       continue;
 344     }
 345
 346     if (current_name && strcmp(current_name, pathname)==0)
 347       continue;
 348
 349     current_name = pathname;
 350     if (!(reg->prot & PROT_READ) && (reg->prot & PROT_EXEC))
 351       continue;
 352
 353     const bool is_executable = !i;
 354     char* libname = NULL;
 355     if (!is_executable) {
 356       libname = MC_get_lib_name(pathname, &res);
 357       if(!libname)
 358         continue;
 359       if (MC_is_filtered_lib(libname)) {
 360         free(libname);
 361         continue;
 362       }
 363     }
 364
 365     mc_object_info_t info =
 366       MC_find_object_info(process->memory_map, pathname, is_executable);
 367     process->object_infos = (mc_object_info_t*) realloc(process->object_infos,
 368       (process->object_infos_size+1) * sizeof(mc_object_info_t*));
 369     process->object_infos[process->object_infos_size] = info;
 370     process->object_infos_size++;
 371     if (is_executable)
 372       process->binary_info = info;
 373     else if (libname && MC_is_simgrid_lib(libname))
 374       process->libsimgrid_info = info;
 375     free(libname);
 376   }
 377
 378   regfree(&res.so_re);
 379   regfree(&res.version_re);
 380
 381   // Resolve time (including accress differents objects):
 382   for (i=0; i!=process->object_infos_size; ++i)
 383     MC_post_process_object_info(process, process->object_infos[i]);
 384
 385   xbt_assert(process->maestro_stack_start, "Did not find maestro_stack_start");
 386   xbt_assert(process->maestro_stack_end, "Did not find maestro_stack_end");
 387
 388   XBT_DEBUG("Get debug information done !");
 389 }
 390
 391 mc_object_info_t MC_process_find_object_info(mc_process_t process, const void *addr)
 392 {
 393   size_t i;
 394   for (i = 0; i != process->object_infos_size; ++i) {
 395     if (addr >= (void *) process->object_infos[i]->start
 396         && addr <= (void *) process->object_infos[i]->end) {
 397       return process->object_infos[i];
 398     }
 399   }
 400   return NULL;
 401 }
 402
 403 mc_object_info_t MC_process_find_object_info_exec(mc_process_t process, const void *addr)
 404 {
 405   size_t i;
 406   for (i = 0; i != process->object_infos_size; ++i) {
 407     if (addr >= (void *) process->object_infos[i]->start_exec
 408         && addr <= (void *) process->object_infos[i]->end_exec) {
 409       return process->object_infos[i];
 410     }
 411   }
 412   return NULL;
 413 }
 414
 415 mc_object_info_t MC_process_find_object_info_rw(mc_process_t process, const void *addr)
 416 {
 417   size_t i;
 418   for (i = 0; i != process->object_infos_size; ++i) {
 419     if (addr >= (void *) process->object_infos[i]->start_rw
 420         && addr <= (void *) process->object_infos[i]->end_rw) {
 421       return process->object_infos[i];
 422     }
 423   }
 424   return NULL;
 425 }
 426
 427 // Functions, variables…
 428
 429 dw_frame_t MC_process_find_function(mc_process_t process, const void *ip)
 430 {
 431   mc_object_info_t info = MC_process_find_object_info_exec(process, ip);
 432   if (info == NULL)
 433     return NULL;
 434   else
 435     return MC_file_object_info_find_function(info, ip);
 436 }
 437
 438 dw_variable_t MC_process_find_variable_by_name(mc_process_t process, const char* name)
 439 {
 440   const size_t n = process->object_infos_size;
 441   size_t i;
 442
 443   // First lookup the variable in the executable shared object.
 444   // A global variable used directly by the executable code from a library
 445   // is reinstanciated in the executable memory .data/.bss.
 446   // We need to look up the variable in the execvutable first.
 447   if (process->binary_info) {
 448     mc_object_info_t info = process->binary_info;
 449     dw_variable_t var = MC_file_object_info_find_variable_by_name(info, name);
 450     if (var)
 451       return var;
 452   }
 453
 454   for (i=0; i!=n; ++i) {
 455     mc_object_info_t info =process->object_infos[i];
 456     dw_variable_t var = MC_file_object_info_find_variable_by_name(info, name);
 457     if (var)
 458       return var;
 459   }
 460
 461   return NULL;
 462 }
 463
 464 void MC_process_read_variable(mc_process_t process, const char* name, void* target, size_t size)
 465 {
 466   dw_variable_t var = MC_process_find_variable_by_name(process, name);
 467   if (!var->address)
 468     xbt_die("No simple location for this variable");
 469   MC_process_read(process, MC_PROCESS_NO_FLAG, target, var->address, size,
 470     MC_PROCESS_INDEX_ANY);
 471 }
 472
 473 // ***** Memory access
 474
 475 int MC_process_vm_open(pid_t pid, int flags)
 476 {
 477   const size_t buffer_size = 30;
 478   char buffer[buffer_size];
 479   int res = snprintf(buffer, buffer_size, "/proc/%lli/mem", (long long) pid);
 480   if (res < 0 || res >= buffer_size) {
 481     errno = ENAMETOOLONG;
 482     return -1;
 483   }
 484   return open(buffer, flags);
 485 }
 486
 487 static void MC_process_open_memory_file(mc_process_t process)
 488 {
 489   if (MC_process_is_self(process) || process->memory_file >= 0)
 490     return;
 491
 492   int fd = MC_process_vm_open(process->pid, O_RDWR);
 493   if (fd<0)
 494     xbt_die("Could not open file for process virtual address space");
 495   process->memory_file = fd;
 496 }
 497
 498 static ssize_t pread_whole(int fd, void *buf, size_t count, off_t offset)
 499 {
 500   char* buffer = (char*) buf;
 501   ssize_t real_count = count;
 502   while (count) {
 503     ssize_t res = pread(fd, buffer, count, offset);
 504     if (res > 0) {
 505       count  -= res;
 506       buffer += res;
 507       offset += res;
 508     } else if (res==0) {
 509       return -1;
 510     } else if (errno != EINTR) {
 511       return -1;
 512     }
 513   }
 514   return real_count;
 515 }
 516
 517 static ssize_t pwrite_whole(int fd, const void *buf, size_t count, off_t offset)
 518 {
 519   const char* buffer = (const char*) buf;
 520   ssize_t real_count = count;
 521   while (count) {
 522     ssize_t res = pwrite(fd, buffer, count, offset);
 523     if (res > 0) {
 524       count  -= res;
 525       buffer += res;
 526       offset += res;
 527     } else if (res==0) {
 528       return -1;
 529     } else if (errno != EINTR) {
 530       return -1;
 531     }
 532   }
 533   return real_count;
 534 }
 535
 536 const void* MC_process_read(mc_process_t process, e_adress_space_read_flags_t flags,
 537   void* local, const void* remote, size_t len,
 538   int process_index)
 539 {
 540   if (process_index != MC_PROCESS_INDEX_DISABLED) {
 541     mc_object_info_t info = MC_process_find_object_info_rw(process, remote);
 542     // Segment overlap is not handled.
 543     if (MC_object_info_is_privatized(info)) {
 544       if (process_index < 0)
 545         xbt_die("Missing process index");
 546       // Address translation in the privaization segment:
 547       size_t offset = (const char*) remote - info->start_rw;
 548       remote = (const char*) remote - offset;
 549     }
 550   }
 551
 552   if (MC_process_is_self(process)) {
 553     if (flags & MC_ADDRESS_SPACE_READ_FLAGS_LAZY)
 554       return remote;
 555     else {
 556       memcpy(local, remote, len);
 557       return local;
 558     }
 559   } else {
 560     if (pread_whole(process->memory_file, local, len, (off_t) remote) < 0)
 561       xbt_die("Read from process %lli failed", (long long) process->pid);
 562     return local;
 563   }
 564 }
 565
 566 void MC_process_write(mc_process_t process, const void* local, void* remote, size_t len)
 567 {
 568   if (MC_process_is_self(process)) {
 569     memcpy(remote, local, len);
 570   } else {
 571     if (pwrite_whole(process->memory_file, local, len, (off_t) remote) < 0)
 572       xbt_die("Write to process %lli failed", (long long) process->pid);
 573   }
 574 }
 575
 576 static pthread_once_t zero_buffer_flag = PTHREAD_ONCE_INIT;
 577 static const void* zero_buffer;
 578 static const int zero_buffer_size = 10 * 4096;
 579
 580 static void MC_zero_buffer_init(void)
 581 {
 582   int fd = open("/dev/zero", O_RDONLY);
 583   if (fd<0)
 584     xbt_die("Could not open /dev/zero");
 585   zero_buffer = mmap(NULL, zero_buffer_size, PROT_READ, MAP_SHARED, fd, 0);
 586   if (zero_buffer == MAP_FAILED)
 587     xbt_die("Could not map the zero buffer");
 588   close(fd);
 589 }
 590
 591 void MC_process_clear_memory(mc_process_t process, void* remote, size_t len)
 592 {
 593   if (MC_process_is_self(process)) {
 594     memset(remote, 0, len);
 595   } else {
 596     pthread_once(&zero_buffer_flag, MC_zero_buffer_init);
 597     while (len) {
 598       size_t s = len > zero_buffer_size ? zero_buffer_size : len;
 599       MC_process_write(process, zero_buffer, remote, s);
 600       remote = (char*) remote + s;
 601       len -= s;
 602     }
 603   }
 604 }
 605
 606 /** Get the issuer of a simcall (`req->issuer`)
 607  *
 608  *  In split-process mode, it does the black magic necessary to get an address
 609  *  of a (shallow) copy of the data structure the issuer SIMIX process in the local
 610  *  address space.
 611  *
 612  *  @param process the MCed process
 613  *  @param req     the simcall (copied in the local process)
 614  */
 615 smx_process_t MC_process_get_issuer(mc_process_t process, smx_simcall_t req)
 616 {
 617   if (MC_process_is_self(&mc_model_checker->process))
 618     return req->issuer;
 619
 620   MC_process_refresh_simix_processes(process);
 621
 622   // This is the address of the smx_process in the MCed process:
 623   void* address = req->issuer;
 624
 625   unsigned i;
 626   mc_smx_process_info_t p;
 627
 628   xbt_dynar_foreach_ptr(process->smx_process_infos, i, p)
 629     if (p->address == address)
 630       return &p->copy;
 631   xbt_dynar_foreach_ptr(process->smx_old_process_infos, i, p)
 632     if (p->address == address)
 633       return &p->copy;
 634
 635   xbt_die("Issuer not found");
 636 }
 637
 638 void MC_simcall_handle(smx_simcall_t req, int value)
 639 {
 640   if (MC_process_is_self(&mc_model_checker->process)) {
 641     SIMIX_simcall_handle(req, value);
 642     return;
 643   }
 644
 645   MC_process_refresh_simix_processes(&mc_model_checker->process);
 646
 647   unsigned i;
 648   mc_smx_process_info_t pi = NULL;
 649
 650   xbt_dynar_foreach_ptr(mc_model_checker->process.smx_process_infos, i, pi) {
 651     smx_process_t p = (smx_process_t) pi->address;
 652     if (req == &pi->copy.simcall) {
 653       smx_simcall_t real_req = &p->simcall;
 654       // TODO, use a remote call
 655       SIMIX_simcall_handle(real_req, value);
 656       return;
 657     }
 658   }
 659
 660   // Check (remove afterwards):
 661   xbt_dynar_foreach_ptr(mc_model_checker->process.smx_process_infos, i, pi) {
 662     smx_process_t p = (smx_process_t) pi->address;
 663     if (req == &p->simcall)
 664       xbt_die("The real simcall was passed. We expected the local copy.");
 665   }
 666
 667   xbt_die("Could not find the request");
 668 }
 669
 670 void mc_smx_process_info_clear(mc_smx_process_info_t p)
 671 {
 672   // Nothing yet
 673 }