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 "AddressSpace.hpp"
  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 using simgrid::mc::remote;
  38
  39 extern "C" {
  40
  41 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_process, mc,
  42                                 "MC process information");
  43
  44 // ***** Helper stuff
  45
  46 #define SO_RE "\\.so[\\.0-9]*$"
  47 #define VERSION_RE "-[\\.0-9]*$"
  48
  49 static const char *const FILTERED_LIBS[] = {
  50   "libstdc++",
  51   "libc++",
  52   "libm",
  53   "libgcc_s",
  54   "libpthread",
  55   "libunwind",
  56   "libunwind-x86_64",
  57   "libunwind-x86",
  58   "libunwind-ptrace",
  59   "libdw",
  60   "libdl",
  61   "librt",
  62   "liblzma",
  63   "libelf",
  64   "libbz2",
  65   "libz",
  66   "libelf",
  67   "libc",
  68   "ld"
  69 };
  70
  71 static bool MC_is_simgrid_lib(const char* libname)
  72 {
  73   return !strcmp(libname, "libsimgrid");
  74 }
  75
  76 static bool MC_is_filtered_lib(const char* libname)
  77 {
  78   for (const char* filtered_lib : FILTERED_LIBS)
  79     if (strcmp(libname, filtered_lib)==0)
  80       return true;
  81   return false;
  82 }
  83
  84 struct s_mc_memory_map_re {
  85   regex_t so_re;
  86   regex_t version_re;
  87 };
  88
  89 static char* MC_get_lib_name(const char* pathname, struct s_mc_memory_map_re* res)
  90 {
  91   const char* map_basename = basename((char*) pathname);
  92
  93   regmatch_t match;
  94   if(regexec(&res->so_re, map_basename, 1, &match, 0))
  95     return NULL;
  96
  97   char* libname = strndup(map_basename, match.rm_so);
  98
  99   // Strip the version suffix:
 100   if(libname && !regexec(&res->version_re, libname, 1, &match, 0)) {
 101     char* temp = libname;
 102     libname = strndup(temp, match.rm_so);
 103     free(temp);
 104   }
 105
 106   return libname;
 107 }
 108
 109 static ssize_t pread_whole(int fd, void *buf, size_t count, off_t offset)
 110 {
 111   char* buffer = (char*) buf;
 112   ssize_t real_count = count;
 113   while (count) {
 114     ssize_t res = pread(fd, buffer, count, offset);
 115     if (res > 0) {
 116       count  -= res;
 117       buffer += res;
 118       offset += res;
 119     } else if (res==0) {
 120       return -1;
 121     } else if (errno != EINTR) {
 122       return -1;
 123     }
 124   }
 125   return real_count;
 126 }
 127
 128 static ssize_t pwrite_whole(int fd, const void *buf, size_t count, off_t offset)
 129 {
 130   const char* buffer = (const char*) buf;
 131   ssize_t real_count = count;
 132   while (count) {
 133     ssize_t res = pwrite(fd, buffer, count, offset);
 134     if (res > 0) {
 135       count  -= res;
 136       buffer += res;
 137       offset += res;
 138     } else if (res==0) {
 139       return -1;
 140     } else if (errno != EINTR) {
 141       return -1;
 142     }
 143   }
 144   return real_count;
 145 }
 146
 147 static pthread_once_t zero_buffer_flag = PTHREAD_ONCE_INIT;
 148 static const void* zero_buffer;
 149 static const size_t zero_buffer_size = 10 * 4096;
 150
 151 static void MC_zero_buffer_init(void)
 152 {
 153   int fd = open("/dev/zero", O_RDONLY);
 154   if (fd<0)
 155     xbt_die("Could not open /dev/zero");
 156   zero_buffer = mmap(NULL, zero_buffer_size, PROT_READ, MAP_SHARED, fd, 0);
 157   if (zero_buffer == MAP_FAILED)
 158     xbt_die("Could not map the zero buffer");
 159   close(fd);
 160 }
 161
 162 }
 163
 164 namespace simgrid {
 165 namespace mc {
 166
 167 int open_vm(pid_t pid, int flags)
 168 {
 169   const size_t buffer_size = 30;
 170   char buffer[buffer_size];
 171   int res = snprintf(buffer, buffer_size, "/proc/%lli/mem", (long long) pid);
 172   if (res < 0 || (size_t) res >= buffer_size) {
 173     errno = ENAMETOOLONG;
 174     return -1;
 175   }
 176   return open(buffer, flags);
 177 }
 178
 179
 180 }
 181 }
 182
 183 // ***** Process
 184
 185 namespace simgrid {
 186 namespace mc {
 187
 188 Process::Process(pid_t pid, int sockfd)
 189 {
 190   Process* process = this;
 191
 192   process->process_flags = MC_PROCESS_NO_FLAG;
 193   process->socket = sockfd;
 194   process->pid = pid;
 195   if (pid==getpid())
 196     process->process_flags |= MC_PROCESS_SELF_FLAG;
 197   process->running = true;
 198   process->status = 0;
 199   process->memory_map = MC_get_memory_map(pid);
 200   process->cache_flags = MC_PROCESS_CACHE_FLAG_NONE;
 201   process->heap = NULL;
 202   process->heap_info = NULL;
 203   process->init_memory_map_info();
 204
 205   // Open the memory file
 206   if (process->is_self())
 207     process->memory_file = -1;
 208   else {
 209     int fd = open_vm(process->pid, O_RDWR);
 210     if (fd<0)
 211       xbt_die("Could not open file for process virtual address space");
 212     process->memory_file = fd;
 213   }
 214
 215   // Read std_heap (is a struct mdesc*):
 216   dw_variable_t std_heap_var = process->find_variable("__mmalloc_default_mdp");
 217   if (!std_heap_var)
 218     xbt_die("No heap information in the target process");
 219   if(!std_heap_var->address)
 220     xbt_die("No constant address for this variable");
 221   process->read_bytes(&process->heap_address, sizeof(struct mdesc*),
 222     remote(std_heap_var->address),
 223     simgrid::mc::ProcessIndexDisabled);
 224
 225   process->smx_process_infos = MC_smx_process_info_list_new();
 226   process->smx_old_process_infos = MC_smx_process_info_list_new();
 227
 228   process->checkpoint_ignore = MC_checkpoint_ignore_new();
 229
 230   process->unw_addr_space = unw_create_addr_space(&mc_unw_accessors  , __BYTE_ORDER);
 231   if (process->process_flags & MC_PROCESS_SELF_FLAG) {
 232     process->unw_underlying_addr_space = unw_local_addr_space;
 233     process->unw_underlying_context = NULL;
 234   } else {
 235     process->unw_underlying_addr_space = unw_create_addr_space(&mc_unw_vmread_accessors, __BYTE_ORDER);
 236     process->unw_underlying_context = _UPT_create(pid);
 237   }
 238 }
 239
 240 Process::~Process()
 241 {
 242   Process* process = this;
 243
 244   process->process_flags = MC_PROCESS_NO_FLAG;
 245   process->pid = 0;
 246
 247   MC_free_memory_map(process->memory_map);
 248   process->memory_map = NULL;
 249
 250   process->maestro_stack_start = NULL;
 251   process->maestro_stack_end = NULL;
 252
 253   xbt_dynar_free(&process->checkpoint_ignore);
 254
 255   xbt_dynar_free(&process->smx_process_infos);
 256   xbt_dynar_free(&process->smx_old_process_infos);
 257
 258   size_t i;
 259   for (i=0; i!=process->object_infos_size; ++i) {
 260     MC_free_object_info(&process->object_infos[i]);
 261   }
 262   free(process->object_infos);
 263   process->object_infos = NULL;
 264   process->object_infos_size = 0;
 265   if (process->memory_file >= 0) {
 266     close(process->memory_file);
 267   }
 268
 269   if (process->unw_underlying_addr_space != unw_local_addr_space) {
 270     unw_destroy_addr_space(process->unw_underlying_addr_space);
 271     _UPT_destroy(process->unw_underlying_context);
 272   }
 273   process->unw_underlying_context = NULL;
 274   process->unw_underlying_addr_space = NULL;
 275
 276   unw_destroy_addr_space(process->unw_addr_space);
 277   process->unw_addr_space = NULL;
 278
 279   process->cache_flags = MC_PROCESS_CACHE_FLAG_NONE;
 280
 281   free(process->heap);
 282   process->heap = NULL;
 283
 284   free(process->heap_info);
 285   process->heap_info = NULL;
 286 }
 287
 288 /** Refresh the information about the process
 289  *
 290  *  Do not use direclty, this is used by the getters when appropriate
 291  *  in order to have fresh data.
 292  */
 293 void Process::refresh_heap()
 294 {
 295   xbt_assert(mc_mode == MC_MODE_SERVER);
 296   xbt_assert(!this->is_self());
 297   // Read/dereference/refresh the std_heap pointer:
 298   if (!this->heap) {
 299     this->heap = (struct mdesc*) malloc(sizeof(struct mdesc));
 300   }
 301   this->read_bytes(this->heap, sizeof(struct mdesc), remote(this->heap_address),
 302     simgrid::mc::ProcessIndexDisabled);
 303   this->cache_flags |= MC_PROCESS_CACHE_FLAG_HEAP;
 304 }
 305
 306 /** Refresh the information about the process
 307  *
 308  *  Do not use direclty, this is used by the getters when appropriate
 309  *  in order to have fresh data.
 310  * */
 311 void Process::refresh_malloc_info()
 312 {
 313   xbt_assert(mc_mode == MC_MODE_SERVER);
 314   xbt_assert(!this->is_self());
 315   if (!(this->cache_flags & MC_PROCESS_CACHE_FLAG_HEAP))
 316     this->refresh_heap();
 317   // Refresh process->heapinfo:
 318   size_t malloc_info_bytesize =
 319     (this->heap->heaplimit + 1) * sizeof(malloc_info);
 320   this->heap_info = (malloc_info*) realloc(this->heap_info, malloc_info_bytesize);
 321   this->read_bytes(this->heap_info, malloc_info_bytesize,
 322     remote(this->heap->heapinfo), simgrid::mc::ProcessIndexDisabled);
 323   this->cache_flags |= MC_PROCESS_CACHE_FLAG_MALLOC_INFO;
 324 }
 325
 326 /** @brief Finds the range of the different memory segments and binary paths */
 327 void Process::init_memory_map_info()
 328 {
 329   XBT_DEBUG("Get debug information ...");
 330   this->maestro_stack_start = NULL;
 331   this->maestro_stack_end = NULL;
 332   this->object_infos = NULL;
 333   this->object_infos_size = 0;
 334   this->binary_info = NULL;
 335   this->libsimgrid_info = NULL;
 336
 337   struct s_mc_memory_map_re res;
 338
 339   if(regcomp(&res.so_re, SO_RE, 0) || regcomp(&res.version_re, VERSION_RE, 0))
 340     xbt_die(".so regexp did not compile");
 341
 342   memory_map_t maps = this->memory_map;
 343
 344   const char* current_name = NULL;
 345
 346   for (ssize_t i=0; i < maps->mapsize; i++) {
 347     map_region_t reg = &(maps->regions[i]);
 348     const char* pathname = maps->regions[i].pathname;
 349
 350     // Nothing to do
 351     if (maps->regions[i].pathname == NULL) {
 352       current_name = NULL;
 353       continue;
 354     }
 355
 356     // [stack], [vvar], [vsyscall], [vdso] ...
 357     if (pathname[0] == '[') {
 358       if ((reg->prot & PROT_WRITE) && !memcmp(pathname, "[stack]", 7)) {
 359         this->maestro_stack_start = reg->start_addr;
 360         this->maestro_stack_end = reg->end_addr;
 361       }
 362       current_name = NULL;
 363       continue;
 364     }
 365
 366     if (current_name && strcmp(current_name, pathname)==0)
 367       continue;
 368
 369     current_name = pathname;
 370     if (!(reg->prot & PROT_READ) && (reg->prot & PROT_EXEC))
 371       continue;
 372
 373     const bool is_executable = !i;
 374     char* libname = NULL;
 375     if (!is_executable) {
 376       libname = MC_get_lib_name(pathname, &res);
 377       if(!libname)
 378         continue;
 379       if (MC_is_filtered_lib(libname)) {
 380         free(libname);
 381         continue;
 382       }
 383     }
 384
 385     mc_object_info_t info =
 386       MC_find_object_info(this->memory_map, pathname, is_executable);
 387     this->object_infos = (mc_object_info_t*) realloc(this->object_infos,
 388       (this->object_infos_size+1) * sizeof(mc_object_info_t*));
 389     this->object_infos[this->object_infos_size] = info;
 390     this->object_infos_size++;
 391     if (is_executable)
 392       this->binary_info = info;
 393     else if (libname && MC_is_simgrid_lib(libname))
 394       this->libsimgrid_info = info;
 395     free(libname);
 396   }
 397
 398   regfree(&res.so_re);
 399   regfree(&res.version_re);
 400
 401   // Resolve time (including accross differents objects):
 402   for (size_t i=0; i!=this->object_infos_size; ++i)
 403     MC_post_process_object_info(this, this->object_infos[i]);
 404
 405   xbt_assert(this->maestro_stack_start, "Did not find maestro_stack_start");
 406   xbt_assert(this->maestro_stack_end, "Did not find maestro_stack_end");
 407
 408   XBT_DEBUG("Get debug information done !");
 409 }
 410
 411 mc_object_info_t Process::find_object_info(remote_ptr<void> addr) const
 412 {
 413   size_t i;
 414   for (i = 0; i != this->object_infos_size; ++i) {
 415     if (addr.address() >= (std::uint64_t)this->object_infos[i]->start
 416         && addr.address() <= (std::uint64_t)this->object_infos[i]->end) {
 417       return this->object_infos[i];
 418     }
 419   }
 420   return NULL;
 421 }
 422
 423 mc_object_info_t Process::find_object_info_exec(remote_ptr<void> addr) const
 424 {
 425   size_t i;
 426   for (i = 0; i != this->object_infos_size; ++i) {
 427     if (addr.address() >= (std::uint64_t)this->object_infos[i]->start_exec
 428         && addr.address() <= (std::uint64_t)this->object_infos[i]->end_exec) {
 429       return this->object_infos[i];
 430     }
 431   }
 432   return NULL;
 433 }
 434
 435 mc_object_info_t Process::find_object_info_rw(remote_ptr<void> addr) const
 436 {
 437   size_t i;
 438   for (i = 0; i != this->object_infos_size; ++i) {
 439     if (addr.address() >= (std::uint64_t)this->object_infos[i]->start_rw
 440         && addr.address() <= (std::uint64_t)this->object_infos[i]->end_rw) {
 441       return this->object_infos[i];
 442     }
 443   }
 444   return NULL;
 445 }
 446
 447 dw_frame_t Process::find_function(remote_ptr<void> ip) const
 448 {
 449   mc_object_info_t info = this->find_object_info_exec(ip);
 450   if (info == NULL)
 451     return NULL;
 452   else
 453     return MC_file_object_info_find_function(info, (void*) ip.address());
 454 }
 455
 456 /** Find (one occurence of) the named variable definition
 457  */
 458 dw_variable_t Process::find_variable(const char* name) const
 459 {
 460   const size_t n = this->object_infos_size;
 461   size_t i;
 462
 463   // First lookup the variable in the executable shared object.
 464   // A global variable used directly by the executable code from a library
 465   // is reinstanciated in the executable memory .data/.bss.
 466   // We need to look up the variable in the execvutable first.
 467   if (this->binary_info) {
 468     mc_object_info_t info = this->binary_info;
 469     dw_variable_t var = MC_file_object_info_find_variable_by_name(info, name);
 470     if (var)
 471       return var;
 472   }
 473
 474   for (i=0; i!=n; ++i) {
 475     mc_object_info_t info = this->object_infos[i];
 476     dw_variable_t var = MC_file_object_info_find_variable_by_name(info, name);
 477     if (var)
 478       return var;
 479   }
 480
 481   return NULL;
 482 }
 483
 484 void Process::read_variable(const char* name, void* target, size_t size) const
 485 {
 486   dw_variable_t var = this->find_variable(name);
 487   if (!var->address)
 488     xbt_die("No simple location for this variable");
 489   if (!var->type->full_type)
 490     xbt_die("Partial type for %s, cannot check size", name);
 491   if ((size_t) var->type->full_type->byte_size != size)
 492     xbt_die("Unexpected size for %s (expected %zi, was %zi)",
 493       name, size, (size_t) var->type->full_type->byte_size);
 494   this->read_bytes(target, size, remote(var->address));
 495 }
 496
 497 char* Process::read_string(remote_ptr<void> address) const
 498 {
 499   if (!address)
 500     return NULL;
 501   if (this->is_self())
 502     return strdup((char*) address.address());
 503
 504   off_t len = 128;
 505   char* res = (char*) malloc(len);
 506   off_t off = 0;
 507
 508   while (1) {
 509     ssize_t c = pread(this->memory_file, res + off, len - off, (off_t) address.address() + off);
 510     if (c == -1) {
 511       if (errno == EINTR)
 512         continue;
 513       else
 514         xbt_die("Could not read from from remote process");
 515     }
 516     if (c==0)
 517       xbt_die("Could not read string from remote process");
 518
 519     void* p = memchr(res + off, '\0', c);
 520     if (p)
 521       return res;
 522
 523     off += c;
 524     if (off == len) {
 525       len *= 2;
 526       res = (char*) realloc(res, len);
 527     }
 528   }
 529 }
 530
 531 const void *Process::read_bytes(void* buffer, std::size_t size,
 532   remote_ptr<void> address, int process_index,
 533   AddressSpace::ReadMode mode) const
 534 {
 535   if (process_index != simgrid::mc::ProcessIndexDisabled) {
 536     mc_object_info_t info = this->find_object_info_rw((void*)address.address());
 537     // Segment overlap is not handled.
 538     if (MC_object_info_is_privatized(info)) {
 539       if (process_index < 0)
 540         xbt_die("Missing process index");
 541       // Address translation in the privaization segment:
 542       // TODO, fix me (broken)
 543       size_t offset = address.address() - (std::uint64_t)info->start_rw;
 544       address = remote(address.address() - offset);
 545     }
 546   }
 547
 548   if (this->is_self()) {
 549     if (mode == simgrid::mc::AddressSpace::Lazy)
 550       return (void*)address.address();
 551     else {
 552       memcpy(buffer, (void*)address.address(), size);
 553       return buffer;
 554     }
 555   } else {
 556     if (pread_whole(this->memory_file, buffer, size, (off_t) address.address()) < 0)
 557       xbt_die("Read from process %lli failed", (long long) this->pid);
 558     return buffer;
 559   }
 560 }
 561
 562 /** Write data to a process memory
 563  *
 564  *  @param process the process
 565  *  @param local   local memory address (source)
 566  *  @param remote  target process memory address (target)
 567  *  @param len     data size
 568  */
 569 void Process::write_bytes(const void* buffer, size_t len, remote_ptr<void> address)
 570 {
 571   if (this->is_self()) {
 572     memcpy((void*)address.address(), buffer, len);
 573   } else {
 574     if (pwrite_whole(this->memory_file, buffer, len, address.address()) < 0)
 575       xbt_die("Write to process %lli failed", (long long) this->pid);
 576   }
 577 }
 578
 579 void Process::clear_bytes(remote_ptr<void> address, size_t len)
 580 {
 581   if (this->is_self()) {
 582     memset((void*)address.address(), 0, len);
 583   } else {
 584     pthread_once(&zero_buffer_flag, MC_zero_buffer_init);
 585     while (len) {
 586       size_t s = len > zero_buffer_size ? zero_buffer_size : len;
 587       this->write_bytes(zero_buffer, s, address);
 588       address = remote((char*) address.address() + s);
 589       len -= s;
 590     }
 591   }
 592 }
 593
 594 }
 595 }