src/mc/remote/RemoteClient.cpp

   1 /* Copyright (c) 2014-2017. The SimGrid Team. All rights reserved.          */
   2
   3 /* This program is free software; you can redistribute it and/or modify it
   4  * under the terms of the license (GNU LGPL) which comes with this package. */
   5
   6 #define _FILE_OFFSET_BITS 64 /* needed for pread_whole to work as expected on 32bits */
   7
   8 #include <algorithm>
   9 #include <cassert>
  10 #include <cerrno>
  11 #include <cstddef>
  12 #include <cstdint>
  13 #include <string>
  14 #include <vector>
  15
  16 #include <sys/ptrace.h>
  17
  18 #include <cstdio>
  19
  20 #include <fcntl.h>
  21 #include <sys/mman.h> // PROT_*
  22 #include <sys/types.h>
  23 #include <unistd.h>
  24
  25 #include <pthread.h>
  26
  27 #include <libgen.h>
  28
  29 #include <libunwind-ptrace.h>
  30 #include <libunwind.h>
  31
  32 #include "xbt/base.h"
  33 #include "xbt/file.hpp"
  34 #include "xbt/log.h"
  35 #include <xbt/mmalloc.h>
  36
  37 #include "src/mc/mc_smx.hpp"
  38 #include "src/mc/mc_snapshot.hpp"
  39 #include "src/mc/mc_unw.hpp"
  40
  41 #include "src/mc/AddressSpace.hpp"
  42 #include "src/mc/ObjectInformation.hpp"
  43 #include "src/mc/Variable.hpp"
  44 #include "src/mc/remote/RemoteClient.hpp"
  45
  46 using simgrid::mc::remote;
  47
  48 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_process, mc, "MC process information");
  49
  50 namespace simgrid {
  51 namespace mc {
  52
  53 // ***** Helper stuff
  54
  55 // List of library which memory segments are not considered:
  56 static const std::vector<std::string> filtered_libraries = {
  57 #ifdef __linux__
  58     "ld",
  59 #elif defined __FreeBSD__
  60     "ld-elf",
  61     "ld-elf32",
  62     "libkvm",      /* kernel data access library */
  63     "libprocstat", /* process and file information retrieval */
  64     "libthr",      /* thread library */
  65     "libutil",
  66 #endif
  67     "libasan", /* gcc sanitizers */
  68     "libargp", /* workarounds for glibc-less systems */
  69     "libtsan",
  70     "libubsan",
  71     "libbz2",
  72     "libboost_chrono",
  73     "libboost_context",
  74     "libboost_context-mt",
  75     "libboost_system",
  76     "libboost_thread",
  77     "libc",
  78     "libc++",
  79     "libcdt",
  80     "libcgraph",
  81     "libcrypto",
  82     "libcxxrt",
  83     "libdl",
  84     "libdw",
  85     "libelf",
  86     "libevent",
  87     "libgcc_s",
  88     "liblua5.1",
  89     "liblua5.3",
  90     "liblzma",
  91     "libm",
  92     "libpthread",
  93     "librt",
  94     "libstdc++",
  95     "libunwind",
  96     "libunwind-x86_64",
  97     "libunwind-x86",
  98     "libunwind-ptrace",
  99     "libz"};
 100
 101 static bool is_simgrid_lib(const std::string& libname)
 102 {
 103   return libname == "libsimgrid";
 104 }
 105
 106 static bool is_filtered_lib(const std::string& libname)
 107 {
 108   return std::find(begin(filtered_libraries), end(filtered_libraries), libname) != end(filtered_libraries);
 109 }
 110
 111 static std::string get_lib_name(const std::string& pathname)
 112 {
 113   constexpr char digits[]  = ".0123456789";
 114   std::string map_basename = simgrid::xbt::Path(pathname).getBasename();
 115   std::string libname;
 116
 117   size_t pos = map_basename.rfind(".so");
 118   if (pos != std::string::npos && map_basename.find_first_not_of(digits, pos + 3) == std::string::npos) {
 119     // strip the extension (matching regex "\.so[.0-9]*$")
 120     libname.assign(map_basename, 0, pos);
 121
 122     // strip the version suffix (matching regex "-[.0-9-]*$")
 123     while (true) {
 124       pos = libname.rfind('-');
 125       if (pos == std::string::npos || libname.find_first_not_of(digits, pos + 1) != std::string::npos)
 126         break;
 127       libname.erase(pos);
 128     }
 129   }
 130
 131   return libname;
 132 }
 133
 134 static ssize_t pread_whole(int fd, void* buf, size_t count, off_t offset)
 135 {
 136   char* buffer       = (char*)buf;
 137   ssize_t real_count = count;
 138   while (count) {
 139     ssize_t res = pread(fd, buffer, count, offset);
 140     if (res > 0) {
 141       count -= res;
 142       buffer += res;
 143       offset += res;
 144     } else if (res == 0)
 145       return -1;
 146     else if (errno != EINTR) {
 147       perror("pread_whole");
 148       return -1;
 149     }
 150   }
 151   return real_count;
 152 }
 153
 154 static ssize_t pwrite_whole(int fd, const void* buf, size_t count, off_t offset)
 155 {
 156   const char* buffer = (const char*)buf;
 157   ssize_t real_count = count;
 158   while (count) {
 159     ssize_t res = pwrite(fd, buffer, count, offset);
 160     if (res > 0) {
 161       count -= res;
 162       buffer += res;
 163       offset += res;
 164     } else if (res == 0)
 165       return -1;
 166     else if (errno != EINTR)
 167       return -1;
 168   }
 169   return real_count;
 170 }
 171
 172 static pthread_once_t zero_buffer_flag = PTHREAD_ONCE_INIT;
 173 static const void* zero_buffer;
 174 static const size_t zero_buffer_size = 10 * 4096;
 175
 176 static void zero_buffer_init()
 177 {
 178   int fd = open("/dev/zero", O_RDONLY);
 179   if (fd < 0)
 180     xbt_die("Could not open /dev/zero");
 181   zero_buffer = mmap(nullptr, zero_buffer_size, PROT_READ, MAP_SHARED, fd, 0);
 182   if (zero_buffer == MAP_FAILED)
 183     xbt_die("Could not map the zero buffer");
 184   close(fd);
 185 }
 186
 187 int open_vm(pid_t pid, int flags)
 188 {
 189   const size_t buffer_size = 30;
 190   char buffer[buffer_size];
 191   int res = snprintf(buffer, buffer_size, "/proc/%lli/mem", (long long)pid);
 192   if (res < 0 || (size_t)res >= buffer_size) {
 193     errno = ENAMETOOLONG;
 194     return -1;
 195   }
 196   return open(buffer, flags);
 197 }
 198
 199 // ***** Process
 200
 201 RemoteClient::RemoteClient(pid_t pid, int sockfd) : AddressSpace(this), pid_(pid), channel_(sockfd), running_(true)
 202 {
 203 }
 204
 205 void RemoteClient::init()
 206 {
 207   this->memory_map_ = simgrid::xbt::get_memory_map(this->pid_);
 208   this->init_memory_map_info();
 209
 210   int fd = open_vm(this->pid_, O_RDWR);
 211   if (fd < 0)
 212     xbt_die("Could not open file for process virtual address space");
 213   this->memory_file = fd;
 214
 215   // Read std_heap (is a struct mdesc*):
 216   simgrid::mc::Variable* std_heap_var = this->find_variable("__mmalloc_default_mdp");
 217   if (not std_heap_var)
 218     xbt_die("No heap information in the target process");
 219   if (not std_heap_var->address)
 220     xbt_die("No constant address for this variable");
 221   this->read_bytes(&this->heap_address, sizeof(mdesc*), remote(std_heap_var->address),
 222                    simgrid::mc::ProcessIndexDisabled);
 223
 224   this->smx_actors_infos.clear();
 225   this->smx_dead_actors_infos.clear();
 226   this->unw_addr_space            = simgrid::mc::UnwindContext::createUnwindAddressSpace();
 227   this->unw_underlying_addr_space = simgrid::unw::create_addr_space();
 228   this->unw_underlying_context    = simgrid::unw::create_context(this->unw_underlying_addr_space, this->pid_);
 229 }
 230
 231 RemoteClient::~RemoteClient()
 232 {
 233   if (this->memory_file >= 0)
 234     close(this->memory_file);
 235
 236   if (this->unw_underlying_addr_space != unw_local_addr_space) {
 237     if (this->unw_underlying_addr_space)
 238       unw_destroy_addr_space(this->unw_underlying_addr_space);
 239     if (this->unw_underlying_context)
 240       _UPT_destroy(this->unw_underlying_context);
 241   }
 242
 243   unw_destroy_addr_space(this->unw_addr_space);
 244 }
 245
 246 /** Refresh the information about the process
 247  *
 248  *  Do not use directly, this is used by the getters when appropriate
 249  *  in order to have fresh data.
 250  */
 251 void RemoteClient::refresh_heap()
 252 {
 253   // Read/dereference/refresh the std_heap pointer:
 254   if (not this->heap)
 255     this->heap = std::unique_ptr<s_xbt_mheap_t>(new s_xbt_mheap_t());
 256   this->read_bytes(this->heap.get(), sizeof(mdesc), remote(this->heap_address), simgrid::mc::ProcessIndexDisabled);
 257   this->cache_flags_ |= RemoteClient::cache_heap;
 258 }
 259
 260 /** Refresh the information about the process
 261  *
 262  *  Do not use direclty, this is used by the getters when appropriate
 263  *  in order to have fresh data.
 264  * */
 265 void RemoteClient::refresh_malloc_info()
 266 {
 267   // Refresh process->heapinfo:
 268   if (this->cache_flags_ & RemoteClient::cache_malloc)
 269     return;
 270   size_t count = this->heap->heaplimit + 1;
 271   if (this->heap_info.size() < count)
 272     this->heap_info.resize(count);
 273   this->read_bytes(this->heap_info.data(), count * sizeof(malloc_info), remote(this->heap->heapinfo),
 274                    simgrid::mc::ProcessIndexDisabled);
 275   this->cache_flags_ |= RemoteClient::cache_malloc;
 276 }
 277
 278 /** @brief Finds the range of the different memory segments and binary paths */
 279 void RemoteClient::init_memory_map_info()
 280 {
 281   XBT_DEBUG("Get debug information ...");
 282   this->maestro_stack_start_ = nullptr;
 283   this->maestro_stack_end_   = nullptr;
 284   this->object_infos.resize(0);
 285   this->binary_info     = nullptr;
 286   this->libsimgrid_info = nullptr;
 287
 288   std::vector<simgrid::xbt::VmMap> const& maps = this->memory_map_;
 289
 290   const char* current_name = nullptr;
 291
 292   this->object_infos.clear();
 293
 294   for (size_t i = 0; i < maps.size(); i++) {
 295     simgrid::xbt::VmMap const& reg = maps[i];
 296     const char* pathname           = maps[i].pathname.c_str();
 297
 298     // Nothing to do
 299     if (maps[i].pathname.empty()) {
 300       current_name = nullptr;
 301       continue;
 302     }
 303
 304     // [stack], [vvar], [vsyscall], [vdso] ...
 305     if (pathname[0] == '[') {
 306       if ((reg.prot & PROT_WRITE) && not memcmp(pathname, "[stack]", 7)) {
 307         this->maestro_stack_start_ = remote(reg.start_addr);
 308         this->maestro_stack_end_   = remote(reg.end_addr);
 309       }
 310       current_name = nullptr;
 311       continue;
 312     }
 313
 314     if (current_name && strcmp(current_name, pathname) == 0)
 315       continue;
 316
 317     current_name = pathname;
 318     if (not(reg.prot & PROT_READ) && (reg.prot & PROT_EXEC))
 319       continue;
 320
 321     const bool is_executable = not i;
 322     std::string libname;
 323     if (not is_executable) {
 324       libname = get_lib_name(pathname);
 325       if (is_filtered_lib(libname)) {
 326         continue;
 327       }
 328     }
 329
 330     std::shared_ptr<simgrid::mc::ObjectInformation> info =
 331         simgrid::mc::createObjectInformation(this->memory_map_, pathname);
 332     this->object_infos.push_back(info);
 333     if (is_executable)
 334       this->binary_info = info;
 335     else if (is_simgrid_lib(libname))
 336       this->libsimgrid_info = info;
 337   }
 338
 339   // Resolve time (including across different objects):
 340   for (auto const& object_info : this->object_infos)
 341     postProcessObjectInformation(this, object_info.get());
 342
 343   xbt_assert(this->maestro_stack_start_, "Did not find maestro_stack_start");
 344   xbt_assert(this->maestro_stack_end_, "Did not find maestro_stack_end");
 345
 346   XBT_DEBUG("Get debug information done !");
 347 }
 348
 349 std::shared_ptr<simgrid::mc::ObjectInformation> RemoteClient::find_object_info(RemotePtr<void> addr) const
 350 {
 351   for (auto const& object_info : this->object_infos)
 352     if (addr.address() >= (std::uint64_t)object_info->start && addr.address() <= (std::uint64_t)object_info->end)
 353       return object_info;
 354   return nullptr;
 355 }
 356
 357 std::shared_ptr<ObjectInformation> RemoteClient::find_object_info_exec(RemotePtr<void> addr) const
 358 {
 359   for (std::shared_ptr<ObjectInformation> const& info : this->object_infos)
 360     if (addr.address() >= (std::uint64_t)info->start_exec && addr.address() <= (std::uint64_t)info->end_exec)
 361       return info;
 362   return nullptr;
 363 }
 364
 365 std::shared_ptr<ObjectInformation> RemoteClient::find_object_info_rw(RemotePtr<void> addr) const
 366 {
 367   for (std::shared_ptr<ObjectInformation> const& info : this->object_infos)
 368     if (addr.address() >= (std::uint64_t)info->start_rw && addr.address() <= (std::uint64_t)info->end_rw)
 369       return info;
 370   return nullptr;
 371 }
 372
 373 simgrid::mc::Frame* RemoteClient::find_function(RemotePtr<void> ip) const
 374 {
 375   std::shared_ptr<simgrid::mc::ObjectInformation> info = this->find_object_info_exec(ip);
 376   return info ? info->find_function((void*)ip.address()) : nullptr;
 377 }
 378
 379 /** Find (one occurrence of) the named variable definition
 380  */
 381 simgrid::mc::Variable* RemoteClient::find_variable(const char* name) const
 382 {
 383   // First lookup the variable in the executable shared object.
 384   // A global variable used directly by the executable code from a library
 385   // is reinstanciated in the executable memory .data/.bss.
 386   // We need to look up the variable in the executable first.
 387   if (this->binary_info) {
 388     std::shared_ptr<simgrid::mc::ObjectInformation> const& info = this->binary_info;
 389     simgrid::mc::Variable* var                                  = info->find_variable(name);
 390     if (var)
 391       return var;
 392   }
 393
 394   for (std::shared_ptr<simgrid::mc::ObjectInformation> const& info : this->object_infos) {
 395     simgrid::mc::Variable* var = info->find_variable(name);
 396     if (var)
 397       return var;
 398   }
 399
 400   return nullptr;
 401 }
 402
 403 void RemoteClient::read_variable(const char* name, void* target, size_t size) const
 404 {
 405   simgrid::mc::Variable* var = this->find_variable(name);
 406   xbt_assert(var->address, "No simple location for this variable");
 407   xbt_assert(var->type->full_type, "Partial type for %s, cannot check size", name);
 408   xbt_assert((size_t)var->type->full_type->byte_size == size, "Unexpected size for %s (expected %zu, was %zu)", name,
 409              size, (size_t)var->type->full_type->byte_size);
 410   this->read_bytes(target, size, remote(var->address));
 411 }
 412
 413 std::string RemoteClient::read_string(RemotePtr<char> address) const
 414 {
 415   if (not address)
 416     return {};
 417
 418   // TODO, use std::vector with .data() in C++17 to avoid useless copies
 419   std::vector<char> res(128);
 420   off_t off = 0;
 421
 422   while (1) {
 423     ssize_t c = pread(this->memory_file, res.data() + off, res.size() - off, (off_t)address.address() + off);
 424     if (c == -1) {
 425       if (errno == EINTR)
 426         continue;
 427       else
 428         xbt_die("Could not read from from remote process");
 429     }
 430     if (c == 0)
 431       xbt_die("Could not read string from remote process");
 432
 433     void* p = memchr(res.data() + off, '\0', c);
 434     if (p)
 435       return std::string(res.data());
 436
 437     off += c;
 438     if (off == (off_t)res.size())
 439       res.resize(res.size() * 2);
 440   }
 441 }
 442
 443 const void* RemoteClient::read_bytes(void* buffer, std::size_t size, RemotePtr<void> address, int process_index,
 444                                      ReadOptions options) const
 445 {
 446   if (process_index != simgrid::mc::ProcessIndexDisabled) {
 447     std::shared_ptr<simgrid::mc::ObjectInformation> const& info = this->find_object_info_rw((void*)address.address());
 448 // Segment overlap is not handled.
 449 #if HAVE_SMPI
 450     if (info.get() && this->privatized(*info)) {
 451       if (process_index < 0)
 452         xbt_die("Missing process index");
 453       if (process_index >= (int)MC_smpi_process_count())
 454         xbt_die("Invalid process index");
 455
 456       // Read smpi_privatization_regions from MCed:
 457       smpi_privatization_region_t remote_smpi_privatization_regions =
 458           mc_model_checker->process().read_variable<smpi_privatization_region_t>("smpi_privatization_regions");
 459
 460       s_smpi_privatization_region_t privatization_region =
 461           mc_model_checker->process().read<s_smpi_privatization_region_t>(
 462               remote(remote_smpi_privatization_regions + process_index));
 463
 464       // Address translation in the privatization segment:
 465       size_t offset = address.address() - (std::uint64_t)info->start_rw;
 466       address       = remote((char*)privatization_region.address + offset);
 467     }
 468 #endif
 469   }
 470   if (pread_whole(this->memory_file, buffer, size, (size_t)address.address()) < 0)
 471     xbt_die("Read at %p from process %lli failed", (void*)address.address(), (long long)this->pid_);
 472   return buffer;
 473 }
 474
 475 /** Write data to a process memory
 476  *
 477  *  @param buffer   local memory address (source)
 478  *  @param len      data size
 479  *  @param address  target process memory address (target)
 480  */
 481 void RemoteClient::write_bytes(const void* buffer, size_t len, RemotePtr<void> address)
 482 {
 483   if (pwrite_whole(this->memory_file, buffer, len, (size_t)address.address()) < 0)
 484     xbt_die("Write to process %lli failed", (long long)this->pid_);
 485 }
 486
 487 void RemoteClient::clear_bytes(RemotePtr<void> address, size_t len)
 488 {
 489   pthread_once(&zero_buffer_flag, zero_buffer_init);
 490   while (len) {
 491     size_t s = len > zero_buffer_size ? zero_buffer_size : len;
 492     this->write_bytes(zero_buffer, s, address);
 493     address = remote((char*)address.address() + s);
 494     len -= s;
 495   }
 496 }
 497
 498 void RemoteClient::ignore_region(std::uint64_t addr, std::size_t size)
 499 {
 500   IgnoredRegion region;
 501   region.addr = addr;
 502   region.size = size;
 503
 504   if (ignored_regions_.empty()) {
 505     ignored_regions_.push_back(region);
 506     return;
 507   }
 508
 509   unsigned int cursor           = 0;
 510   IgnoredRegion* current_region = nullptr;
 511
 512   int start = 0;
 513   int end   = ignored_regions_.size() - 1;
 514   while (start <= end) {
 515     cursor         = (start + end) / 2;
 516     current_region = &ignored_regions_[cursor];
 517     if (current_region->addr == addr) {
 518       if (current_region->size == size)
 519         return;
 520       else if (current_region->size < size)
 521         start = cursor + 1;
 522       else
 523         end = cursor - 1;
 524     } else if (current_region->addr < addr)
 525       start = cursor + 1;
 526     else
 527       end = cursor - 1;
 528   }
 529
 530   std::size_t position;
 531   if (current_region->addr == addr) {
 532     if (current_region->size < size)
 533       position = cursor + 1;
 534     else
 535       position = cursor;
 536   } else if (current_region->addr < addr)
 537     position = cursor + 1;
 538   else
 539     position = cursor;
 540   ignored_regions_.insert(ignored_regions_.begin() + position, region);
 541 }
 542
 543 void RemoteClient::ignore_heap(IgnoredHeapRegion const& region)
 544 {
 545   if (ignored_heap_.empty()) {
 546     ignored_heap_.push_back(std::move(region));
 547     return;
 548   }
 549
 550   typedef std::vector<IgnoredHeapRegion>::size_type size_type;
 551
 552   size_type start = 0;
 553   size_type end   = ignored_heap_.size() - 1;
 554
 555   // Binary search the position of insertion:
 556   size_type cursor;
 557   while (start <= end) {
 558     cursor               = start + (end - start) / 2;
 559     auto& current_region = ignored_heap_[cursor];
 560     if (current_region.address == region.address)
 561       return;
 562     else if (current_region.address < region.address)
 563       start = cursor + 1;
 564     else if (cursor != 0)
 565       end = cursor - 1;
 566     // Avoid underflow:
 567     else
 568       break;
 569   }
 570
 571   // Insert it mc_heap_ignore_region_t:
 572   if (ignored_heap_[cursor].address < region.address)
 573     ++cursor;
 574   ignored_heap_.insert(ignored_heap_.begin() + cursor, region);
 575 }
 576
 577 void RemoteClient::unignore_heap(void* address, size_t size)
 578 {
 579   typedef std::vector<IgnoredHeapRegion>::size_type size_type;
 580
 581   size_type start = 0;
 582   size_type end   = ignored_heap_.size() - 1;
 583
 584   // Binary search:
 585   size_type cursor;
 586   while (start <= end) {
 587     cursor       = (start + end) / 2;
 588     auto& region = ignored_heap_[cursor];
 589     if (region.address < address)
 590       start = cursor + 1;
 591     else if ((char*)region.address <= ((char*)address + size)) {
 592       ignored_heap_.erase(ignored_heap_.begin() + cursor);
 593       return;
 594     } else if (cursor != 0)
 595       end = cursor - 1;
 596     // Avoid underflow:
 597     else
 598       break;
 599   }
 600 }
 601
 602 void RemoteClient::ignore_local_variable(const char* var_name, const char* frame_name)
 603 {
 604   if (frame_name != nullptr && strcmp(frame_name, "*") == 0)
 605     frame_name = nullptr;
 606   for (std::shared_ptr<simgrid::mc::ObjectInformation> const& info : this->object_infos)
 607     info->remove_local_variable(var_name, frame_name);
 608 }
 609
 610 std::vector<simgrid::mc::ActorInformation>& RemoteClient::actors()
 611 {
 612   this->refresh_simix();
 613   return smx_actors_infos;
 614 }
 615
 616 std::vector<simgrid::mc::ActorInformation>& RemoteClient::dead_actors()
 617 {
 618   this->refresh_simix();
 619   return smx_dead_actors_infos;
 620 }
 621
 622 void RemoteClient::dumpStack()
 623 {
 624   unw_addr_space_t as = unw_create_addr_space(&_UPT_accessors, BYTE_ORDER);
 625   if (as == nullptr) {
 626     XBT_ERROR("Could not initialize ptrace address space");
 627     return;
 628   }
 629
 630   void* context = _UPT_create(this->pid_);
 631   if (context == nullptr) {
 632     unw_destroy_addr_space(as);
 633     XBT_ERROR("Could not initialize ptrace context");
 634     return;
 635   }
 636
 637   unw_cursor_t cursor;
 638   if (unw_init_remote(&cursor, as, context) != 0) {
 639     _UPT_destroy(context);
 640     unw_destroy_addr_space(as);
 641     XBT_ERROR("Could not initialiez ptrace cursor");
 642     return;
 643   }
 644
 645   simgrid::mc::dumpStack(stderr, cursor);
 646
 647   _UPT_destroy(context);
 648   unw_destroy_addr_space(as);
 649 }
 650
 651 bool RemoteClient::actor_is_enabled(aid_t pid)
 652 {
 653   s_mc_message_actor_enabled msg{MC_MESSAGE_ACTOR_ENABLED, pid};
 654   process()->getChannel().send(msg);
 655   char buff[MC_MESSAGE_LENGTH];
 656   ssize_t received = process()->getChannel().receive(buff, MC_MESSAGE_LENGTH, true);
 657   xbt_assert(received == sizeof(s_mc_message_int), "Unexpected size in answer to ACTOR_ENABLED");
 658   return ((mc_message_int_t*)buff)->value;
 659 }
 660 }
 661 }