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   assert(!MC_process_is_self(process));
 158   // Read/dereference/refresh the std_heap pointer:
 159   if (!process->heap) {
 160     xbt_mheap_t oldheap  = mmalloc_set_current_heap(mc_heap);
 161     process->heap = (struct mdesc*) malloc(sizeof(struct mdesc));
 162     mmalloc_set_current_heap(oldheap);
 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 }
 169
 170 void MC_process_refresh_malloc_info(mc_process_t process)
 171 {
 172   assert(!MC_process_is_self(process));
 173   if (!(process->cache_flags & MC_PROCESS_CACHE_FLAG_HEAP))
 174     MC_process_refresh_heap(process);
 175   // Refresh process->heapinfo:
 176   size_t malloc_info_bytesize =
 177     (process->heap->heaplimit + 1) * sizeof(malloc_info);
 178
 179   xbt_mheap_t heap  = mmalloc_set_current_heap(mc_heap);
 180   process->heap_info = (malloc_info*) realloc(process->heap_info, malloc_info_bytesize);
 181   mmalloc_set_current_heap(heap);
 182
 183   MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE,
 184     process->heap_info,
 185     process->heap->heapinfo, malloc_info_bytesize,
 186     MC_PROCESS_INDEX_DISABLED);
 187 }
 188
 189 #define SO_RE "\\.so[\\.0-9]*$"
 190 #define VERSION_RE "-[\\.0-9]*$"
 191
 192 const char* FILTERED_LIBS[] = {
 193   "libstdc++",
 194   "libc++",
 195   "libm",
 196   "libgcc_s",
 197   "libpthread",
 198   "libunwind",
 199   "libunwind-x86_64",
 200   "libunwind-x86",
 201   "libunwind-ptrace",
 202   "libdw",
 203   "libdl",
 204   "librt",
 205   "liblzma",
 206   "libelf",
 207   "libbz2",
 208   "libz",
 209   "libelf",
 210   "libc",
 211   "ld"
 212 };
 213
 214 static bool MC_is_simgrid_lib(const char* libname)
 215 {
 216   return !strcmp(libname, "libsimgrid");
 217 }
 218
 219 static bool MC_is_filtered_lib(const char* libname)
 220 {
 221   const size_t n = sizeof(FILTERED_LIBS) / sizeof(const char*);
 222   size_t i;
 223   for (i=0; i!=n; ++i)
 224     if (strcmp(libname, FILTERED_LIBS[i])==0)
 225       return true;
 226   return false;
 227 }
 228
 229 struct s_mc_memory_map_re {
 230   regex_t so_re;
 231   regex_t version_re;
 232 };
 233
 234 static char* MC_get_lib_name(const char* pathname, struct s_mc_memory_map_re* res) {
 235   const char* map_basename = basename((char*) pathname);
 236
 237   regmatch_t match;
 238   if(regexec(&res->so_re, map_basename, 1, &match, 0))
 239     return NULL;
 240
 241   char* libname = strndup(map_basename, match.rm_so);
 242
 243   // Strip the version suffix:
 244   if(libname && !regexec(&res->version_re, libname, 1, &match, 0)) {
 245     char* temp = libname;
 246     libname = strndup(temp, match.rm_so);
 247     free(temp);
 248   }
 249
 250   return libname;
 251 }
 252
 253 /** @brief Finds the range of the different memory segments and binary paths */
 254 static void MC_process_init_memory_map_info(mc_process_t process)
 255 {
 256   XBT_DEBUG("Get debug information ...");
 257   process->maestro_stack_start = NULL;
 258   process->maestro_stack_end = NULL;
 259   process->object_infos = NULL;
 260   process->object_infos_size = 0;
 261   process->binary_info = NULL;
 262   process->libsimgrid_info = NULL;
 263
 264   struct s_mc_memory_map_re res;
 265
 266   if(regcomp(&res.so_re, SO_RE, 0) || regcomp(&res.version_re, VERSION_RE, 0))
 267     xbt_die(".so regexp did not compile");
 268
 269   memory_map_t maps = process->memory_map;
 270
 271   const char* current_name = NULL;
 272
 273   for (ssize_t i=0; i < maps->mapsize; i++) {
 274     map_region_t reg = &(maps->regions[i]);
 275     const char* pathname = maps->regions[i].pathname;
 276
 277     // Nothing to do
 278     if (maps->regions[i].pathname == NULL) {
 279       current_name = NULL;
 280       continue;
 281     }
 282
 283     // [stack], [vvar], [vsyscall], [vdso] ...
 284     if (pathname[0] == '[') {
 285       if ((reg->prot & PROT_WRITE) && !memcmp(pathname, "[stack]", 7)) {
 286         process->maestro_stack_start = reg->start_addr;
 287         process->maestro_stack_end = reg->end_addr;
 288       }
 289       current_name = NULL;
 290       continue;
 291     }
 292
 293     if (current_name && strcmp(current_name, pathname)==0)
 294       continue;
 295
 296     current_name = pathname;
 297     if (!(reg->prot & PROT_READ) && (reg->prot & PROT_EXEC))
 298       continue;
 299
 300     const bool is_executable = !i;
 301     char* libname = NULL;
 302     if (!is_executable) {
 303       libname = MC_get_lib_name(pathname, &res);
 304       if(!libname)
 305         continue;
 306       if (MC_is_filtered_lib(libname)) {
 307         free(libname);
 308         continue;
 309       }
 310     }
 311
 312     mc_object_info_t info =
 313       MC_find_object_info(process->memory_map, pathname, is_executable);
 314     process->object_infos = (mc_object_info_t*) realloc(process->object_infos,
 315       (process->object_infos_size+1) * sizeof(mc_object_info_t*));
 316     process->object_infos[process->object_infos_size] = info;
 317     process->object_infos_size++;
 318     if (is_executable)
 319       process->binary_info = info;
 320     else if (libname && MC_is_simgrid_lib(libname))
 321       process->libsimgrid_info = info;
 322     free(libname);
 323   }
 324
 325   regfree(&res.so_re);
 326   regfree(&res.version_re);
 327
 328   // Resolve time (including accress differents objects):
 329   for (size_t i=0; i!=process->object_infos_size; ++i)
 330     MC_post_process_object_info(process, process->object_infos[i]);
 331
 332   xbt_assert(process->maestro_stack_start, "Did not find maestro_stack_start");
 333   xbt_assert(process->maestro_stack_end, "Did not find maestro_stack_end");
 334
 335   XBT_DEBUG("Get debug information done !");
 336 }
 337
 338 mc_object_info_t MC_process_find_object_info(mc_process_t process, const void *addr)
 339 {
 340   size_t i;
 341   for (i = 0; i != process->object_infos_size; ++i) {
 342     if (addr >= (void *) process->object_infos[i]->start
 343         && addr <= (void *) process->object_infos[i]->end) {
 344       return process->object_infos[i];
 345     }
 346   }
 347   return NULL;
 348 }
 349
 350 mc_object_info_t MC_process_find_object_info_exec(mc_process_t process, const void *addr)
 351 {
 352   size_t i;
 353   for (i = 0; i != process->object_infos_size; ++i) {
 354     if (addr >= (void *) process->object_infos[i]->start_exec
 355         && addr <= (void *) process->object_infos[i]->end_exec) {
 356       return process->object_infos[i];
 357     }
 358   }
 359   return NULL;
 360 }
 361
 362 mc_object_info_t MC_process_find_object_info_rw(mc_process_t process, const void *addr)
 363 {
 364   size_t i;
 365   for (i = 0; i != process->object_infos_size; ++i) {
 366     if (addr >= (void *) process->object_infos[i]->start_rw
 367         && addr <= (void *) process->object_infos[i]->end_rw) {
 368       return process->object_infos[i];
 369     }
 370   }
 371   return NULL;
 372 }
 373
 374 // Functions, variables…
 375
 376 dw_frame_t MC_process_find_function(mc_process_t process, const void *ip)
 377 {
 378   mc_object_info_t info = MC_process_find_object_info_exec(process, ip);
 379   if (info == NULL)
 380     return NULL;
 381   else
 382     return MC_file_object_info_find_function(info, ip);
 383 }
 384
 385 dw_variable_t MC_process_find_variable_by_name(mc_process_t process, const char* name)
 386 {
 387   const size_t n = process->object_infos_size;
 388   size_t i;
 389
 390   // First lookup the variable in the executable shared object.
 391   // A global variable used directly by the executable code from a library
 392   // is reinstanciated in the executable memory .data/.bss.
 393   // We need to look up the variable in the execvutable first.
 394   if (process->binary_info) {
 395     mc_object_info_t info = process->binary_info;
 396     dw_variable_t var = MC_file_object_info_find_variable_by_name(info, name);
 397     if (var)
 398       return var;
 399   }
 400
 401   for (i=0; i!=n; ++i) {
 402     mc_object_info_t info =process->object_infos[i];
 403     dw_variable_t var = MC_file_object_info_find_variable_by_name(info, name);
 404     if (var)
 405       return var;
 406   }
 407
 408   return NULL;
 409 }
 410
 411 void MC_process_read_variable(mc_process_t process, const char* name, void* target, size_t size)
 412 {
 413   dw_variable_t var = MC_process_find_variable_by_name(process, name);
 414   if (!var->address)
 415     xbt_die("No simple location for this variable");
 416   if (!var->type->full_type)
 417     xbt_die("Partial type for %s, cannot check size", name);
 418   if ((size_t) var->type->full_type->byte_size != size)
 419     xbt_die("Unexpected size for %s (expected %zi, was %zi)",
 420       name, size, (size_t) var->type->full_type->byte_size);
 421   MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE, target, var->address, size,
 422     MC_PROCESS_INDEX_ANY);
 423 }
 424
 425 char* MC_process_read_string(mc_process_t process, void* address)
 426 {
 427   if (!address)
 428     return NULL;
 429   if (MC_process_is_self(process))
 430     return strdup((char*) address);
 431
 432   off_t len = 128;
 433   char* res = (char*) malloc(len);
 434   off_t off = 0;
 435
 436   while (1) {
 437     ssize_t c = pread(process->memory_file, res + off, len - off, (off_t) address + off);
 438     if (c == -1) {
 439       if (errno == EINTR)
 440         continue;
 441       else
 442         xbt_die("Could not read from from remote process");
 443     }
 444     if (c==0)
 445       xbt_die("Could not read string from remote process");
 446
 447     void* p = memchr(res + off, '\0', c);
 448     if (p)
 449       return res;
 450
 451     off += c;
 452     if (off == len) {
 453       len *= 2;
 454       res = (char*) realloc(res, len);
 455     }
 456   }
 457 }
 458
 459 // ***** Memory access
 460
 461 int MC_process_vm_open(pid_t pid, int flags)
 462 {
 463   const size_t buffer_size = 30;
 464   char buffer[buffer_size];
 465   int res = snprintf(buffer, buffer_size, "/proc/%lli/mem", (long long) pid);
 466   if (res < 0 || (size_t) res >= buffer_size) {
 467     errno = ENAMETOOLONG;
 468     return -1;
 469   }
 470   return open(buffer, flags);
 471 }
 472
 473 static void MC_process_open_memory_file(mc_process_t process)
 474 {
 475   if (MC_process_is_self(process) || process->memory_file >= 0)
 476     return;
 477
 478   int fd = MC_process_vm_open(process->pid, O_RDWR);
 479   if (fd<0)
 480     xbt_die("Could not open file for process virtual address space");
 481   process->memory_file = fd;
 482 }
 483
 484 static ssize_t pread_whole(int fd, void *buf, size_t count, off_t offset)
 485 {
 486   char* buffer = (char*) buf;
 487   ssize_t real_count = count;
 488   while (count) {
 489     ssize_t res = pread(fd, buffer, count, offset);
 490     if (res > 0) {
 491       count  -= res;
 492       buffer += res;
 493       offset += res;
 494     } else if (res==0) {
 495       return -1;
 496     } else if (errno != EINTR) {
 497       return -1;
 498     }
 499   }
 500   return real_count;
 501 }
 502
 503 static ssize_t pwrite_whole(int fd, const void *buf, size_t count, off_t offset)
 504 {
 505   const char* buffer = (const char*) buf;
 506   ssize_t real_count = count;
 507   while (count) {
 508     ssize_t res = pwrite(fd, buffer, count, offset);
 509     if (res > 0) {
 510       count  -= res;
 511       buffer += res;
 512       offset += res;
 513     } else if (res==0) {
 514       return -1;
 515     } else if (errno != EINTR) {
 516       return -1;
 517     }
 518   }
 519   return real_count;
 520 }
 521
 522 const void* MC_process_read(mc_process_t process, adress_space_read_flags_t flags,
 523   void* local, const void* remote, size_t len,
 524   int process_index)
 525 {
 526   if (process_index != MC_PROCESS_INDEX_DISABLED) {
 527     mc_object_info_t info = MC_process_find_object_info_rw(process, remote);
 528     // Segment overlap is not handled.
 529     if (MC_object_info_is_privatized(info)) {
 530       if (process_index < 0)
 531         xbt_die("Missing process index");
 532       // Address translation in the privaization segment:
 533       size_t offset = (const char*) remote - info->start_rw;
 534       remote = (const char*) remote - offset;
 535     }
 536   }
 537
 538   if (MC_process_is_self(process)) {
 539     if (flags & MC_ADDRESS_SPACE_READ_FLAGS_LAZY)
 540       return remote;
 541     else {
 542       memcpy(local, remote, len);
 543       return local;
 544     }
 545   } else {
 546     if (pread_whole(process->memory_file, local, len, (off_t) remote) < 0)
 547       xbt_die("Read from process %lli failed", (long long) process->pid);
 548     return local;
 549   }
 550 }
 551
 552 const void* MC_process_read_simple(mc_process_t process,
 553   void* local, const void* remote, size_t len)
 554 {
 555   adress_space_read_flags_t flags = MC_ADDRESS_SPACE_READ_FLAGS_NONE;
 556   int index = MC_PROCESS_INDEX_ANY;
 557    MC_process_read(process, flags, local, remote, len, index);
 558    return local;
 559 }
 560
 561 const void* MC_process_read_dynar_element(mc_process_t process,
 562   void* local, const void* remote_dynar, size_t i, size_t len)
 563 {
 564   s_xbt_dynar_t d;
 565   MC_process_read_simple(process, &d, remote_dynar, sizeof(d));
 566   if (i >= d.used)
 567     xbt_die("Out of bound index %zi/%zi", i, d.used);
 568   if (len != d.elmsize)
 569     xbt_die("Bad size in MC_process_read_dynar_element");
 570   MC_process_read_simple(process, local, xbt_dynar_get_ptr(&d, i), len);
 571   return local;
 572 }
 573
 574 void MC_process_write(mc_process_t process, const void* local, void* remote, size_t len)
 575 {
 576   if (MC_process_is_self(process)) {
 577     memcpy(remote, local, len);
 578   } else {
 579     if (pwrite_whole(process->memory_file, local, len, (off_t) remote) < 0)
 580       xbt_die("Write to process %lli failed", (long long) process->pid);
 581   }
 582 }
 583
 584 unsigned long MC_process_read_dynar_length(mc_process_t process, const void* remote_dynar)
 585 {
 586   if (!remote_dynar)
 587     return 0;
 588   unsigned long res;
 589   MC_process_read_simple(process, &res,
 590     &((xbt_dynar_t)remote_dynar)->used, sizeof(res));
 591   return res;
 592 }
 593
 594 static pthread_once_t zero_buffer_flag = PTHREAD_ONCE_INIT;
 595 static const void* zero_buffer;
 596 static const int zero_buffer_size = 10 * 4096;
 597
 598 static void MC_zero_buffer_init(void)
 599 {
 600   int fd = open("/dev/zero", O_RDONLY);
 601   if (fd<0)
 602     xbt_die("Could not open /dev/zero");
 603   zero_buffer = mmap(NULL, zero_buffer_size, PROT_READ, MAP_SHARED, fd, 0);
 604   if (zero_buffer == MAP_FAILED)
 605     xbt_die("Could not map the zero buffer");
 606   close(fd);
 607 }
 608
 609 void MC_process_clear_memory(mc_process_t process, void* remote, size_t len)
 610 {
 611   if (MC_process_is_self(process)) {
 612     memset(remote, 0, len);
 613   } else {
 614     pthread_once(&zero_buffer_flag, MC_zero_buffer_init);
 615     while (len) {
 616       size_t s = len > zero_buffer_size ? zero_buffer_size : len;
 617       MC_process_write(process, zero_buffer, remote, s);
 618       remote = (char*) remote + s;
 619       len -= s;
 620     }
 621   }
 622 }
 623
 624 }