src/mc/mc_process.cpp

   1 /* Copyright (c) 2014-2015. The SimGrid Team.
   2  * All rights reserved.                                                     */
   3
   4 /* This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the license (GNU LGPL) which comes with this package. */
   6
   7 #include <assert.h>
   8 #include <stddef.h>
   9 #include <stdbool.h>
  10 #include <stdint.h>
  11 #include <errno.h>
  12
  13 #include <sys/types.h>
  14 #include <fcntl.h>
  15 #include <unistd.h>
  16 #include <regex.h>
  17 #include <sys/mman.h> // PROT_*
  18
  19 #include <pthread.h>
  20
  21 #include <libgen.h>
  22
  23 #include <libunwind.h>
  24 #include <libunwind-ptrace.h>
  25
  26 #include <xbt/mmalloc.h>
  27
  28 #include "mc_process.h"
  29 #include "mc_object_info.h"
  30 #include "mc_address_space.h"
  31 #include "mc_unw.h"
  32 #include "mc_snapshot.h"
  33 #include "mc_ignore.h"
  34 #include "mc_smx.h"
  35 #include "mc_server.h"
  36
  37 extern "C" {
  38
  39 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_process, mc,
  40                                 "MC process information");
  41
  42 static void MC_process_init_memory_map_info(mc_process_t process);
  43 static void MC_process_open_memory_file(mc_process_t process);
  44
  45 // ***** Destructor callbacks
  46
  47 // ***** mc_address_space methods for mc_process
  48
  49 static mc_process_t MC_process_get_process(mc_process_t p) {
  50   return p;
  51 }
  52
  53 static const s_mc_address_space_class_t mc_process_class = {
  54   (mc_address_space_class_read_callback_t) &MC_process_read,
  55   (mc_address_space_class_get_process_callback_t) MC_process_get_process
  56 };
  57
  58 bool MC_is_process(mc_address_space_t p)
  59 {
  60   return p->address_space_class == &mc_process_class;
  61 }
  62
  63 // ***** mc_process
  64
  65 void MC_process_init(mc_process_t process, pid_t pid, int sockfd)
  66 {
  67   process->address_space.address_space_class = &mc_process_class;
  68   process->process_flags = MC_PROCESS_NO_FLAG;
  69   process->socket = sockfd;
  70   process->pid = pid;
  71   if (pid==getpid())
  72     process->process_flags |= MC_PROCESS_SELF_FLAG;
  73   process->running = true;
  74   process->status = 0;
  75   process->memory_map = MC_get_memory_map(pid);
  76   process->memory_file = -1;
  77   process->cache_flags = MC_PROCESS_CACHE_FLAG_NONE;
  78   process->heap = NULL;
  79   process->heap_info = NULL;
  80   MC_process_init_memory_map_info(process);
  81   MC_process_open_memory_file(process);
  82
  83   // Read std_heap (is a struct mdesc*):
  84   dw_variable_t std_heap_var = MC_process_find_variable_by_name(process,
  85     "__mmalloc_default_mdp");
  86   if (!std_heap_var)
  87     xbt_die("No heap information in the target process");
  88   if(!std_heap_var->address)
  89     xbt_die("No constant address for this variable");
  90   MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE,
  91     &process->heap_address, std_heap_var->address, sizeof(struct mdesc*),
  92     MC_PROCESS_INDEX_DISABLED);
  93
  94   process->smx_process_infos = MC_smx_process_info_list_new();
  95   process->smx_old_process_infos = MC_smx_process_info_list_new();
  96
  97   process->checkpoint_ignore = MC_checkpoint_ignore_new();
  98
  99   process->unw_addr_space = unw_create_addr_space(&mc_unw_accessors  , __BYTE_ORDER);
 100   if (process->process_flags & MC_PROCESS_SELF_FLAG) {
 101     process->unw_underlying_addr_space = unw_local_addr_space;
 102     process->unw_underlying_context = NULL;
 103   } else {
 104     process->unw_underlying_addr_space = unw_create_addr_space(&mc_unw_vmread_accessors, __BYTE_ORDER);
 105     process->unw_underlying_context = _UPT_create(pid);
 106   }
 107 }
 108
 109 void MC_process_clear(mc_process_t process)
 110 {
 111   process->address_space.address_space_class = NULL;
 112   process->process_flags = MC_PROCESS_NO_FLAG;
 113   process->pid = 0;
 114
 115   MC_free_memory_map(process->memory_map);
 116   process->memory_map = NULL;
 117
 118   process->maestro_stack_start = NULL;
 119   process->maestro_stack_end = NULL;
 120
 121   xbt_dynar_free(&process->checkpoint_ignore);
 122
 123   xbt_dynar_free(&process->smx_process_infos);
 124   xbt_dynar_free(&process->smx_old_process_infos);
 125
 126   size_t i;
 127   for (i=0; i!=process->object_infos_size; ++i) {
 128     MC_free_object_info(&process->object_infos[i]);
 129   }
 130   free(process->object_infos);
 131   process->object_infos = NULL;
 132   process->object_infos_size = 0;
 133   if (process->memory_file >= 0) {
 134     close(process->memory_file);
 135   }
 136
 137   if (process->unw_underlying_addr_space != unw_local_addr_space) {
 138     unw_destroy_addr_space(process->unw_underlying_addr_space);
 139     _UPT_destroy(process->unw_underlying_context);
 140   }
 141   process->unw_underlying_context = NULL;
 142   process->unw_underlying_addr_space = NULL;
 143
 144   unw_destroy_addr_space(process->unw_addr_space);
 145   process->unw_addr_space = NULL;
 146
 147   process->cache_flags = MC_PROCESS_CACHE_FLAG_NONE;
 148
 149   free(process->heap);
 150   process->heap = NULL;
 151
 152   free(process->heap_info);
 153   process->heap_info = NULL;
 154 }
 155
 156 void MC_process_refresh_heap(mc_process_t process)
 157 {
 158   xbt_assert(mc_mode == MC_MODE_SERVER);
 159   xbt_assert(!MC_process_is_self(process));
 160   // Read/dereference/refresh the std_heap pointer:
 161   if (!process->heap) {
 162     process->heap = (struct mdesc*) malloc(sizeof(struct mdesc));
 163   }
 164   MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE,
 165     process->heap, process->heap_address, sizeof(struct mdesc),
 166     MC_PROCESS_INDEX_DISABLED
 167     );
 168   process->cache_flags |= MC_PROCESS_CACHE_FLAG_HEAP;
 169 }
 170
 171 void MC_process_refresh_malloc_info(mc_process_t process)
 172 {
 173   xbt_assert(mc_mode == MC_MODE_SERVER);
 174   xbt_assert(!MC_process_is_self(process));
 175   if (!(process->cache_flags & MC_PROCESS_CACHE_FLAG_HEAP))
 176     MC_process_refresh_heap(process);
 177   // Refresh process->heapinfo:
 178   size_t malloc_info_bytesize =
 179     (process->heap->heaplimit + 1) * sizeof(malloc_info);
 180   process->heap_info = (malloc_info*) realloc(process->heap_info, malloc_info_bytesize);
 181   MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE,
 182     process->heap_info,
 183     process->heap->heapinfo, malloc_info_bytesize,
 184     MC_PROCESS_INDEX_DISABLED);
 185   process->cache_flags |= MC_PROCESS_CACHE_FLAG_MALLOC_INFO;
 186 }
 187
 188 #define SO_RE "\\.so[\\.0-9]*$"
 189 #define VERSION_RE "-[\\.0-9]*$"
 190
 191 const char* FILTERED_LIBS[] = {
 192   "libstdc++",
 193   "libc++",
 194   "libm",
 195   "libgcc_s",
 196   "libpthread",
 197   "libunwind",
 198   "libunwind-x86_64",
 199   "libunwind-x86",
 200   "libunwind-ptrace",
 201   "libdw",
 202   "libdl",
 203   "librt",
 204   "liblzma",
 205   "libelf",
 206   "libbz2",
 207   "libz",
 208   "libelf",
 209   "libc",
 210   "ld"
 211 };
 212
 213 static bool MC_is_simgrid_lib(const char* libname)
 214 {
 215   return !strcmp(libname, "libsimgrid");
 216 }
 217
 218 static bool MC_is_filtered_lib(const char* libname)
 219 {
 220   const size_t n = sizeof(FILTERED_LIBS) / sizeof(const char*);
 221   size_t i;
 222   for (i=0; i!=n; ++i)
 223     if (strcmp(libname, FILTERED_LIBS[i])==0)
 224       return true;
 225   return false;
 226 }
 227
 228 struct s_mc_memory_map_re {
 229   regex_t so_re;
 230   regex_t version_re;
 231 };
 232
 233 static char* MC_get_lib_name(const char* pathname, struct s_mc_memory_map_re* res) {
 234   const char* map_basename = basename((char*) pathname);
 235
 236   regmatch_t match;
 237   if(regexec(&res->so_re, map_basename, 1, &match, 0))
 238     return NULL;
 239
 240   char* libname = strndup(map_basename, match.rm_so);
 241
 242   // Strip the version suffix:
 243   if(libname && !regexec(&res->version_re, libname, 1, &match, 0)) {
 244     char* temp = libname;
 245     libname = strndup(temp, match.rm_so);
 246     free(temp);
 247   }
 248
 249   return libname;
 250 }
 251
 252 /** @brief Finds the range of the different memory segments and binary paths */
 253 static void MC_process_init_memory_map_info(mc_process_t process)
 254 {
 255   XBT_DEBUG("Get debug information ...");
 256   process->maestro_stack_start = NULL;
 257   process->maestro_stack_end = NULL;
 258   process->object_infos = NULL;
 259   process->object_infos_size = 0;
 260   process->binary_info = NULL;
 261   process->libsimgrid_info = NULL;
 262
 263   struct s_mc_memory_map_re res;
 264
 265   if(regcomp(&res.so_re, SO_RE, 0) || regcomp(&res.version_re, VERSION_RE, 0))
 266     xbt_die(".so regexp did not compile");
 267
 268   memory_map_t maps = process->memory_map;
 269
 270   const char* current_name = NULL;
 271
 272   for (ssize_t i=0; i < maps->mapsize; i++) {
 273     map_region_t reg = &(maps->regions[i]);
 274     const char* pathname = maps->regions[i].pathname;
 275
 276     // Nothing to do
 277     if (maps->regions[i].pathname == NULL) {
 278       current_name = NULL;
 279       continue;
 280     }
 281
 282     // [stack], [vvar], [vsyscall], [vdso] ...
 283     if (pathname[0] == '[') {
 284       if ((reg->prot & PROT_WRITE) && !memcmp(pathname, "[stack]", 7)) {
 285         process->maestro_stack_start = reg->start_addr;
 286         process->maestro_stack_end = reg->end_addr;
 287       }
 288       current_name = NULL;
 289       continue;
 290     }
 291
 292     if (current_name && strcmp(current_name, pathname)==0)
 293       continue;
 294
 295     current_name = pathname;
 296     if (!(reg->prot & PROT_READ) && (reg->prot & PROT_EXEC))
 297       continue;
 298
 299     const bool is_executable = !i;
 300     char* libname = NULL;
 301     if (!is_executable) {
 302       libname = MC_get_lib_name(pathname, &res);
 303       if(!libname)
 304         continue;
 305       if (MC_is_filtered_lib(libname)) {
 306         free(libname);
 307         continue;
 308       }
 309     }
 310
 311     mc_object_info_t info =
 312       MC_find_object_info(process->memory_map, pathname, is_executable);
 313     process->object_infos = (mc_object_info_t*) realloc(process->object_infos,
 314       (process->object_infos_size+1) * sizeof(mc_object_info_t*));
 315     process->object_infos[process->object_infos_size] = info;
 316     process->object_infos_size++;
 317     if (is_executable)
 318       process->binary_info = info;
 319     else if (libname && MC_is_simgrid_lib(libname))
 320       process->libsimgrid_info = info;
 321     free(libname);
 322   }
 323
 324   regfree(&res.so_re);
 325   regfree(&res.version_re);
 326
 327   // Resolve time (including accress differents objects):
 328   for (size_t i=0; i!=process->object_infos_size; ++i)
 329     MC_post_process_object_info(process, process->object_infos[i]);
 330
 331   xbt_assert(process->maestro_stack_start, "Did not find maestro_stack_start");
 332   xbt_assert(process->maestro_stack_end, "Did not find maestro_stack_end");
 333
 334   XBT_DEBUG("Get debug information done !");
 335 }
 336
 337 mc_object_info_t MC_process_find_object_info(mc_process_t process, const void *addr)
 338 {
 339   size_t i;
 340   for (i = 0; i != process->object_infos_size; ++i) {
 341     if (addr >= (void *) process->object_infos[i]->start
 342         && addr <= (void *) process->object_infos[i]->end) {
 343       return process->object_infos[i];
 344     }
 345   }
 346   return NULL;
 347 }
 348
 349 mc_object_info_t MC_process_find_object_info_exec(mc_process_t process, const void *addr)
 350 {
 351   size_t i;
 352   for (i = 0; i != process->object_infos_size; ++i) {
 353     if (addr >= (void *) process->object_infos[i]->start_exec
 354         && addr <= (void *) process->object_infos[i]->end_exec) {
 355       return process->object_infos[i];
 356     }
 357   }
 358   return NULL;
 359 }
 360
 361 mc_object_info_t MC_process_find_object_info_rw(mc_process_t process, const void *addr)
 362 {
 363   size_t i;
 364   for (i = 0; i != process->object_infos_size; ++i) {
 365     if (addr >= (void *) process->object_infos[i]->start_rw
 366         && addr <= (void *) process->object_infos[i]->end_rw) {
 367       return process->object_infos[i];
 368     }
 369   }
 370   return NULL;
 371 }
 372
 373 // Functions, variables…
 374
 375 dw_frame_t MC_process_find_function(mc_process_t process, const void *ip)
 376 {
 377   mc_object_info_t info = MC_process_find_object_info_exec(process, ip);
 378   if (info == NULL)
 379     return NULL;
 380   else
 381     return MC_file_object_info_find_function(info, ip);
 382 }
 383
 384 dw_variable_t MC_process_find_variable_by_name(mc_process_t process, const char* name)
 385 {
 386   const size_t n = process->object_infos_size;
 387   size_t i;
 388
 389   // First lookup the variable in the executable shared object.
 390   // A global variable used directly by the executable code from a library
 391   // is reinstanciated in the executable memory .data/.bss.
 392   // We need to look up the variable in the execvutable first.
 393   if (process->binary_info) {
 394     mc_object_info_t info = process->binary_info;
 395     dw_variable_t var = MC_file_object_info_find_variable_by_name(info, name);
 396     if (var)
 397       return var;
 398   }
 399
 400   for (i=0; i!=n; ++i) {
 401     mc_object_info_t info =process->object_infos[i];
 402     dw_variable_t var = MC_file_object_info_find_variable_by_name(info, name);
 403     if (var)
 404       return var;
 405   }
 406
 407   return NULL;
 408 }
 409
 410 void MC_process_read_variable(mc_process_t process, const char* name, void* target, size_t size)
 411 {
 412   dw_variable_t var = MC_process_find_variable_by_name(process, name);
 413   if (!var->address)
 414     xbt_die("No simple location for this variable");
 415   if (!var->type->full_type)
 416     xbt_die("Partial type for %s, cannot check size", name);
 417   if ((size_t) var->type->full_type->byte_size != size)
 418     xbt_die("Unexpected size for %s (expected %zi, was %zi)",
 419       name, size, (size_t) var->type->full_type->byte_size);
 420   MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE, target, var->address, size,
 421     MC_PROCESS_INDEX_ANY);
 422 }
 423
 424 char* MC_process_read_string(mc_process_t process, void* address)
 425 {
 426   if (!address)
 427     return NULL;
 428   if (MC_process_is_self(process))
 429     return strdup((char*) address);
 430
 431   off_t len = 128;
 432   char* res = (char*) malloc(len);
 433   off_t off = 0;
 434
 435   while (1) {
 436     ssize_t c = pread(process->memory_file, res + off, len - off, (off_t) address + off);
 437     if (c == -1) {
 438       if (errno == EINTR)
 439         continue;
 440       else
 441         xbt_die("Could not read from from remote process");
 442     }
 443     if (c==0)
 444       xbt_die("Could not read string from remote process");
 445
 446     void* p = memchr(res + off, '\0', c);
 447     if (p)
 448       return res;
 449
 450     off += c;
 451     if (off == len) {
 452       len *= 2;
 453       res = (char*) realloc(res, len);
 454     }
 455   }
 456 }
 457
 458 // ***** Memory access
 459
 460 int MC_process_vm_open(pid_t pid, int flags)
 461 {
 462   const size_t buffer_size = 30;
 463   char buffer[buffer_size];
 464   int res = snprintf(buffer, buffer_size, "/proc/%lli/mem", (long long) pid);
 465   if (res < 0 || (size_t) res >= buffer_size) {
 466     errno = ENAMETOOLONG;
 467     return -1;
 468   }
 469   return open(buffer, flags);
 470 }
 471
 472 static void MC_process_open_memory_file(mc_process_t process)
 473 {
 474   if (MC_process_is_self(process) || process->memory_file >= 0)
 475     return;
 476
 477   int fd = MC_process_vm_open(process->pid, O_RDWR);
 478   if (fd<0)
 479     xbt_die("Could not open file for process virtual address space");
 480   process->memory_file = fd;
 481 }
 482
 483 static ssize_t pread_whole(int fd, void *buf, size_t count, off_t offset)
 484 {
 485   char* buffer = (char*) buf;
 486   ssize_t real_count = count;
 487   while (count) {
 488     ssize_t res = pread(fd, buffer, count, offset);
 489     if (res > 0) {
 490       count  -= res;
 491       buffer += res;
 492       offset += res;
 493     } else if (res==0) {
 494       return -1;
 495     } else if (errno != EINTR) {
 496       return -1;
 497     }
 498   }
 499   return real_count;
 500 }
 501
 502 static ssize_t pwrite_whole(int fd, const void *buf, size_t count, off_t offset)
 503 {
 504   const char* buffer = (const char*) buf;
 505   ssize_t real_count = count;
 506   while (count) {
 507     ssize_t res = pwrite(fd, buffer, count, offset);
 508     if (res > 0) {
 509       count  -= res;
 510       buffer += res;
 511       offset += res;
 512     } else if (res==0) {
 513       return -1;
 514     } else if (errno != EINTR) {
 515       return -1;
 516     }
 517   }
 518   return real_count;
 519 }
 520
 521 const void* MC_process_read(mc_process_t process, adress_space_read_flags_t flags,
 522   void* local, const void* remote, size_t len,
 523   int process_index)
 524 {
 525   if (process_index != MC_PROCESS_INDEX_DISABLED) {
 526     mc_object_info_t info = MC_process_find_object_info_rw(process, remote);
 527     // Segment overlap is not handled.
 528     if (MC_object_info_is_privatized(info)) {
 529       if (process_index < 0)
 530         xbt_die("Missing process index");
 531       // Address translation in the privaization segment:
 532       size_t offset = (const char*) remote - info->start_rw;
 533       remote = (const char*) remote - offset;
 534     }
 535   }
 536
 537   if (MC_process_is_self(process)) {
 538     if (flags & MC_ADDRESS_SPACE_READ_FLAGS_LAZY)
 539       return remote;
 540     else {
 541       memcpy(local, remote, len);
 542       return local;
 543     }
 544   } else {
 545     if (pread_whole(process->memory_file, local, len, (off_t) remote) < 0)
 546       xbt_die("Read from process %lli failed", (long long) process->pid);
 547     return local;
 548   }
 549 }
 550
 551 const void* MC_process_read_simple(mc_process_t process,
 552   void* local, const void* remote, size_t len)
 553 {
 554   adress_space_read_flags_t flags = MC_ADDRESS_SPACE_READ_FLAGS_NONE;
 555   int index = MC_PROCESS_INDEX_ANY;
 556    MC_process_read(process, flags, local, remote, len, index);
 557    return local;
 558 }
 559
 560 const void* MC_process_read_dynar_element(mc_process_t process,
 561   void* local, const void* remote_dynar, size_t i, size_t len)
 562 {
 563   s_xbt_dynar_t d;
 564   MC_process_read_simple(process, &d, remote_dynar, sizeof(d));
 565   if (i >= d.used)
 566     xbt_die("Out of bound index %zi/%lu", i, d.used);
 567   if (len != d.elmsize)
 568     xbt_die("Bad size in MC_process_read_dynar_element");
 569   MC_process_read_simple(process, local, xbt_dynar_get_ptr(&d, i), len);
 570   return local;
 571 }
 572
 573 void MC_process_write(mc_process_t process, const void* local, void* remote, size_t len)
 574 {
 575   if (MC_process_is_self(process)) {
 576     memcpy(remote, local, len);
 577   } else {
 578     if (pwrite_whole(process->memory_file, local, len, (off_t) remote) < 0)
 579       xbt_die("Write to process %lli failed", (long long) process->pid);
 580   }
 581 }
 582
 583 unsigned long MC_process_read_dynar_length(mc_process_t process, const void* remote_dynar)
 584 {
 585   if (!remote_dynar)
 586     return 0;
 587   unsigned long res;
 588   MC_process_read_simple(process, &res,
 589     &((xbt_dynar_t)remote_dynar)->used, sizeof(res));
 590   return res;
 591 }
 592
 593 static pthread_once_t zero_buffer_flag = PTHREAD_ONCE_INIT;
 594 static const void* zero_buffer;
 595 static const size_t zero_buffer_size = 10 * 4096;
 596
 597 static void MC_zero_buffer_init(void)
 598 {
 599   int fd = open("/dev/zero", O_RDONLY);
 600   if (fd<0)
 601     xbt_die("Could not open /dev/zero");
 602   zero_buffer = mmap(NULL, zero_buffer_size, PROT_READ, MAP_SHARED, fd, 0);
 603   if (zero_buffer == MAP_FAILED)
 604     xbt_die("Could not map the zero buffer");
 605   close(fd);
 606 }
 607
 608 void MC_process_clear_memory(mc_process_t process, void* remote, size_t len)
 609 {
 610   if (MC_process_is_self(process)) {
 611     memset(remote, 0, len);
 612   } else {
 613     pthread_once(&zero_buffer_flag, MC_zero_buffer_init);
 614     while (len) {
 615       size_t s = len > zero_buffer_size ? zero_buffer_size : len;
 616       MC_process_write(process, zero_buffer, remote, s);
 617       remote = (char*) remote + s;
 618       len -= s;
 619     }
 620   }
 621 }
 622
 623 }