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