1 /* Copyright (c) 2014-2023. The SimGrid Team. All rights reserved. */
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. */
6 #define _FILE_OFFSET_BITS 64 /* needed for pread_whole to work as expected on 32bits */
8 #include "src/mc/sosp/RemoteProcessMemory.hpp"
10 #include "src/mc/explo/Exploration.hpp"
11 #include "src/mc/explo/LivenessChecker.hpp"
12 #include "src/mc/sosp/Snapshot.hpp"
13 #include "xbt/file.hpp"
15 #include "xbt/system_error.hpp"
18 #include <libunwind-ptrace.h>
19 #include <sys/mman.h> // PROT_*
27 #include <string_view>
28 #include <sys/ptrace.h>
31 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_process, mc, "MC process information");
33 namespace simgrid::mc {
37 static bool is_filtered_lib(std::string_view libname)
39 return libname != "libsimgrid";
42 static std::string get_lib_name(const std::string& pathname)
44 std::string map_basename = simgrid::xbt::Path(pathname).get_base_name();
47 if (size_t pos = map_basename.rfind(".so"); pos != std::string::npos) {
48 // strip the extension (matching regex "\.so.*$")
49 libname.assign(map_basename, 0, pos);
51 // strip the version suffix (matching regex "-[.0-9-]*$")
53 pos = libname.rfind('-');
54 if (pos == std::string::npos || libname.find_first_not_of(".0123456789", pos + 1) != std::string::npos)
63 static ssize_t pread_whole(int fd, void* buf, size_t count, off_t offset)
65 auto* buffer = static_cast<char*>(buf);
66 ssize_t real_count = count;
68 ssize_t res = pread(fd, buffer, count, offset);
75 else if (errno != EINTR) {
76 XBT_ERROR("pread_whole: %s", strerror(errno));
83 static ssize_t pwrite_whole(int fd, const void* buf, size_t count, off_t offset)
85 const auto* buffer = static_cast<const char*>(buf);
86 ssize_t real_count = count;
88 ssize_t res = pwrite(fd, buffer, count, offset);
95 else if (errno != EINTR) {
96 XBT_ERROR("pwrite_whole: %s", strerror(errno));
103 int open_vm(pid_t pid, int flags)
105 std::string buffer = "/proc/" + std::to_string(pid) + "/mem";
106 return open(buffer.c_str(), flags);
109 // ***** RemoteProcessMemory
111 RemoteProcessMemory::RemoteProcessMemory(pid_t pid) : AddressSpace(this), pid_(pid), running_(true) {}
113 void RemoteProcessMemory::init(xbt_mheap_t mmalloc_default_mdp)
115 this->heap_address = remote(mmalloc_default_mdp);
117 this->memory_map_ = simgrid::xbt::get_memory_map(this->pid_);
118 this->init_memory_map_info();
120 int fd = open_vm(this->pid_, O_RDWR);
121 xbt_assert(fd >= 0, "Could not open file for process virtual address space");
122 this->memory_file = fd;
124 this->unw_addr_space = simgrid::mc::UnwindContext::createUnwindAddressSpace();
125 this->unw_underlying_addr_space = simgrid::unw::create_addr_space();
126 this->unw_underlying_context = simgrid::unw::create_context(this->unw_underlying_addr_space, this->pid_);
128 auto ignored_local_variables = {
129 std::make_pair("e", "*"),
130 std::make_pair("_log_ev", "*"),
132 /* Ignore local variable about time used for tracing */
133 std::make_pair("start_time", "*"),
135 for (auto const& [var, frame] : ignored_local_variables)
136 ignore_local_variable(var, frame);
138 ignore_global_variable("counter"); // Static variable used for tracing
141 RemoteProcessMemory::~RemoteProcessMemory()
143 if (this->memory_file >= 0)
144 close(this->memory_file);
146 if (this->unw_underlying_addr_space != unw_local_addr_space) {
147 if (this->unw_underlying_addr_space)
148 unw_destroy_addr_space(this->unw_underlying_addr_space);
149 if (this->unw_underlying_context)
150 _UPT_destroy(this->unw_underlying_context);
153 unw_destroy_addr_space(this->unw_addr_space);
156 /** Refresh the information about the process
158 * Do not use directly, this is used by the getters when appropriate
159 * in order to have fresh data.
161 void RemoteProcessMemory::refresh_heap()
163 // Read/dereference/refresh the std_heap pointer:
164 this->read(this->heap.get(), this->heap_address);
165 this->cache_flags_ |= RemoteProcessMemory::cache_heap;
168 /** Refresh the information about the process
170 * Do not use directly, this is used by the getters when appropriate
171 * in order to have fresh data.
173 void RemoteProcessMemory::refresh_malloc_info()
175 // Refresh process->heapinfo:
176 if (this->cache_flags_ & RemoteProcessMemory::cache_malloc)
178 size_t count = this->heap->heaplimit + 1;
179 if (this->heap_info.size() < count)
180 this->heap_info.resize(count);
181 this->read_bytes(this->heap_info.data(), count * sizeof(malloc_info), remote(this->heap->heapinfo));
182 this->cache_flags_ |= RemoteProcessMemory::cache_malloc;
184 std::size_t RemoteProcessMemory::get_remote_heap_bytes()
186 return mmalloc_get_bytes_used_remote(get_heap()->heaplimit, get_malloc_info());
189 /** @brief Finds the range of the different memory segments and binary paths */
190 void RemoteProcessMemory::init_memory_map_info()
192 XBT_DEBUG("Get debug information ...");
193 this->maestro_stack_start_ = nullptr;
194 this->maestro_stack_end_ = nullptr;
195 this->object_infos.clear();
196 this->binary_info = nullptr;
198 std::vector<simgrid::xbt::VmMap> const& maps = this->memory_map_;
200 const char* current_name = nullptr;
202 for (size_t i = 0; i < maps.size(); i++) {
203 simgrid::xbt::VmMap const& reg = maps[i];
204 const char* pathname = maps[i].pathname.c_str();
207 if (maps[i].pathname.empty()) {
208 current_name = nullptr;
212 // [stack], [vvar], [vsyscall], [vdso] ...
213 if (pathname[0] == '[') {
214 if ((reg.prot & PROT_WRITE) && not memcmp(pathname, "[stack]", 7)) {
215 this->maestro_stack_start_ = remote(reg.start_addr);
216 this->maestro_stack_end_ = remote(reg.end_addr);
218 current_name = nullptr;
222 if (current_name && strcmp(current_name, pathname) == 0)
225 current_name = pathname;
226 if (not(reg.prot & PROT_READ) && (reg.prot & PROT_EXEC))
229 const bool is_executable = not i;
231 if (not is_executable) {
232 libname = get_lib_name(pathname);
233 if (is_filtered_lib(libname)) {
238 std::shared_ptr<simgrid::mc::ObjectInformation> info =
239 simgrid::mc::createObjectInformation(this->memory_map_, pathname);
240 this->object_infos.push_back(info);
242 this->binary_info = info;
245 xbt_assert(this->maestro_stack_start_, "Did not find maestro_stack_start");
246 xbt_assert(this->maestro_stack_end_, "Did not find maestro_stack_end");
248 XBT_DEBUG("Get debug information done !");
251 std::shared_ptr<simgrid::mc::ObjectInformation> RemoteProcessMemory::find_object_info(RemotePtr<void> addr) const
253 for (auto const& object_info : this->object_infos)
254 if (addr.address() >= (std::uint64_t)object_info->start && addr.address() <= (std::uint64_t)object_info->end)
259 std::shared_ptr<ObjectInformation> RemoteProcessMemory::find_object_info_exec(RemotePtr<void> addr) const
261 for (std::shared_ptr<ObjectInformation> const& info : this->object_infos)
262 if (addr.address() >= (std::uint64_t)info->start_exec && addr.address() <= (std::uint64_t)info->end_exec)
267 std::shared_ptr<ObjectInformation> RemoteProcessMemory::find_object_info_rw(RemotePtr<void> addr) const
269 for (std::shared_ptr<ObjectInformation> const& info : this->object_infos)
270 if (addr.address() >= (std::uint64_t)info->start_rw && addr.address() <= (std::uint64_t)info->end_rw)
275 simgrid::mc::Frame* RemoteProcessMemory::find_function(RemotePtr<void> ip) const
277 std::shared_ptr<simgrid::mc::ObjectInformation> info = this->find_object_info_exec(ip);
278 return info ? info->find_function((void*)ip.address()) : nullptr;
281 /** Find (one occurrence of) the named variable definition
283 const simgrid::mc::Variable* RemoteProcessMemory::find_variable(const char* name) const
285 // First lookup the variable in the executable shared object.
286 // A global variable used directly by the executable code from a library
287 // is reinstantiated in the executable memory .data/.bss.
288 // We need to look up the variable in the executable first.
289 if (this->binary_info) {
290 std::shared_ptr<simgrid::mc::ObjectInformation> const& info = this->binary_info;
291 const simgrid::mc::Variable* var = info->find_variable(name);
296 for (std::shared_ptr<simgrid::mc::ObjectInformation> const& info : this->object_infos) {
297 const simgrid::mc::Variable* var = info->find_variable(name);
305 void RemoteProcessMemory::read_variable(const char* name, void* target, size_t size) const
307 const simgrid::mc::Variable* var = this->find_variable(name);
308 xbt_assert(var, "Variable %s not found", name);
309 xbt_assert(var->address, "No simple location for this variable");
311 if (not var->type->full_type) // Try to resolve this type. The needed ObjectInfo was maybe (lazily) loaded recently
312 for (auto const& object_info : this->object_infos)
313 postProcessObjectInformation(this, object_info.get());
314 xbt_assert(var->type->full_type, "Partial type for %s (even after re-resolving types), cannot retrieve its size.",
316 xbt_assert((size_t)var->type->full_type->byte_size == size, "Unexpected size for %s (expected %zu, received %zu).",
317 name, size, (size_t)var->type->full_type->byte_size);
318 this->read_bytes(target, size, remote(var->address));
321 std::string RemoteProcessMemory::read_string(RemotePtr<char> address) const
326 std::vector<char> res(128);
330 ssize_t c = pread(this->memory_file, res.data() + off, res.size() - off, (off_t)address.address() + off);
331 if (c == -1 && errno == EINTR)
333 xbt_assert(c > 0, "Could not read string from remote process");
335 if (memchr(res.data() + off, '\0', c))
339 if (off == (off_t)res.size())
340 res.resize(res.size() * 2);
344 void* RemoteProcessMemory::read_bytes(void* buffer, std::size_t size, RemotePtr<void> address,
345 ReadOptions /*options*/) const
347 xbt_assert(pread_whole(this->memory_file, buffer, size, (size_t)address.address()) != -1,
348 "Read at %p from process %lli failed", (void*)address.address(), (long long)this->pid_);
352 /** Write data to a process memory
354 * @param buffer local memory address (source)
355 * @param len data size
356 * @param address target process memory address (target)
358 void RemoteProcessMemory::write_bytes(const void* buffer, size_t len, RemotePtr<void> address) const
360 xbt_assert(pwrite_whole(this->memory_file, buffer, len, (size_t)address.address()) != -1,
361 "Write to process %lli failed", (long long)this->pid_);
364 static void zero_buffer_init(const void** zero_buffer, size_t zero_buffer_size)
366 int fd = open("/dev/zero", O_RDONLY);
367 xbt_assert(fd >= 0, "Could not open /dev/zero");
368 *zero_buffer = mmap(nullptr, zero_buffer_size, PROT_READ, MAP_SHARED, fd, 0);
369 xbt_assert(*zero_buffer != MAP_FAILED, "Could not map the zero buffer");
373 void RemoteProcessMemory::clear_bytes(RemotePtr<void> address, size_t len) const
375 static constexpr size_t zero_buffer_size = 10 * 4096;
376 static const void* zero_buffer;
377 static std::once_flag zero_buffer_flag;
379 std::call_once(zero_buffer_flag, zero_buffer_init, &zero_buffer, zero_buffer_size);
381 size_t s = len > zero_buffer_size ? zero_buffer_size : len;
382 this->write_bytes(zero_buffer, s, address);
383 address = remote((char*)address.address() + s);
388 void RemoteProcessMemory::ignore_region(std::uint64_t addr, std::size_t size)
390 IgnoredRegion region;
394 auto pos = std::lower_bound(ignored_regions_.begin(), ignored_regions_.end(), region,
395 [](auto const& reg1, auto const& reg2) {
396 return reg1.addr < reg2.addr || (reg1.addr == reg2.addr && reg1.size < reg2.size);
398 if (pos == ignored_regions_.end() || pos->addr != addr || pos->size != size)
399 ignored_regions_.insert(pos, region);
402 void RemoteProcessMemory::ignore_heap(IgnoredHeapRegion const& region)
404 // Binary search the position of insertion:
405 auto pos = std::lower_bound(ignored_heap_.begin(), ignored_heap_.end(), region.address,
406 [](auto const& reg, auto const* addr) { return reg.address < addr; });
407 if (pos == ignored_heap_.end() || pos->address != region.address) {
409 ignored_heap_.insert(pos, region);
413 void RemoteProcessMemory::unignore_heap(void* address, size_t size)
416 auto pos = std::lower_bound(ignored_heap_.begin(), ignored_heap_.end(), address,
417 [](auto const& reg, auto const* addr) { return reg.address < addr; });
418 if (pos != ignored_heap_.end() && static_cast<char*>(pos->address) <= static_cast<char*>(address) + size)
419 ignored_heap_.erase(pos);
422 void RemoteProcessMemory::ignore_local_variable(const char* var_name, const char* frame_name) const
424 if (frame_name != nullptr && strcmp(frame_name, "*") == 0)
425 frame_name = nullptr;
426 for (std::shared_ptr<simgrid::mc::ObjectInformation> const& info : this->object_infos)
427 info->remove_local_variable(var_name, frame_name);
430 void RemoteProcessMemory::dump_stack() const
432 unw_addr_space_t as = unw_create_addr_space(&_UPT_accessors, BYTE_ORDER);
434 XBT_ERROR("Could not initialize ptrace address space");
438 void* context = _UPT_create(this->pid_);
439 if (context == nullptr) {
440 unw_destroy_addr_space(as);
441 XBT_ERROR("Could not initialize ptrace context");
446 if (unw_init_remote(&cursor, as, context) != 0) {
447 _UPT_destroy(context);
448 unw_destroy_addr_space(as);
449 XBT_ERROR("Could not initialize ptrace cursor");
453 simgrid::mc::dumpStack(stderr, &cursor);
455 _UPT_destroy(context);
456 unw_destroy_addr_space(as);
459 bool RemoteProcessMemory::handle_message(const char* buffer, ssize_t size)
461 s_mc_message_t base_message;
462 xbt_assert(size >= (ssize_t)sizeof(base_message), "Broken message");
463 memcpy(&base_message, buffer, sizeof(base_message));
465 switch (base_message.type) {
466 case MessageType::INITIAL_ADDRESSES: {
467 s_mc_message_initial_addresses_t message;
468 xbt_assert(size == sizeof(message), "Broken message. Got %d bytes instead of %d.", (int)size,
469 (int)sizeof(message));
470 memcpy(&message, buffer, sizeof(message));
472 this->init(message.mmalloc_default_mdp);
476 case MessageType::IGNORE_HEAP: {
477 s_mc_message_ignore_heap_t message;
478 xbt_assert(size == sizeof(message), "Broken message");
479 memcpy(&message, buffer, sizeof(message));
481 IgnoredHeapRegion region;
482 region.block = message.block;
483 region.fragment = message.fragment;
484 region.address = message.address;
485 region.size = message.size;
486 this->ignore_heap(region);
490 case MessageType::UNIGNORE_HEAP: {
491 s_mc_message_ignore_memory_t message;
492 xbt_assert(size == sizeof(message), "Broken message");
493 memcpy(&message, buffer, sizeof(message));
494 this->unignore_heap((void*)(std::uintptr_t)message.addr, message.size);
498 case MessageType::IGNORE_MEMORY: {
499 s_mc_message_ignore_memory_t message;
500 xbt_assert(size == sizeof(message), "Broken message");
501 memcpy(&message, buffer, sizeof(message));
502 this->ignore_region(message.addr, message.size);
506 case MessageType::STACK_REGION: {
507 s_mc_message_stack_region_t message;
508 xbt_assert(size == sizeof(message), "Broken message");
509 memcpy(&message, buffer, sizeof(message));
510 this->stack_areas().push_back(message.stack_region);
513 case MessageType::REGISTER_SYMBOL: {
514 s_mc_message_register_symbol_t message;
515 xbt_assert(size == sizeof(message), "Broken message");
516 memcpy(&message, buffer, sizeof(message));
517 xbt_assert(not message.callback, "Support for client-side function proposition is not implemented.");
518 XBT_DEBUG("Received symbol: %s", message.name.data());
520 LivenessChecker::automaton_register_symbol(*this, message.name.data(), remote((int*)message.data));
524 case MessageType::WAITING:
527 case MessageType::ASSERTION_FAILED:
528 Exploration::get_instance()->report_assertion_failure();
532 xbt_die("Unexpected message from model-checked application");
537 void RemoteProcessMemory::handle_waitpid()
539 XBT_DEBUG("Check for wait event");
542 while ((pid = waitpid(-1, &status, WNOHANG)) != 0) {
544 if (errno == ECHILD) { // No more children:
545 xbt_assert(not running(), "Inconsistent state");
548 XBT_ERROR("Could not wait for pid");
549 throw simgrid::xbt::errno_error();
553 if (pid == this->pid()) {
554 // From PTRACE_O_TRACEEXIT:
556 if (status >> 8 == (SIGTRAP | (PTRACE_EVENT_EXIT << 8))) {
557 unsigned long eventmsg;
558 xbt_assert(ptrace(PTRACE_GETEVENTMSG, pid, 0, &eventmsg) != -1, "Could not get exit status");
559 status = static_cast<int>(eventmsg);
560 if (WIFSIGNALED(status))
561 Exploration::get_instance()->report_crash(status);
565 // We don't care about non-lethal signals, just reinject them:
566 if (WIFSTOPPED(status)) {
567 XBT_DEBUG("Stopped with signal %i", (int)WSTOPSIG(status));
570 ptrace(PTRACE_CONT, pid, 0, WSTOPSIG(status));
572 ptrace(PT_CONTINUE, pid, (caddr_t)1, WSTOPSIG(status));
574 xbt_assert(errno == 0, "Could not PTRACE_CONT");
577 else if (WIFSIGNALED(status)) {
578 Exploration::get_instance()->report_crash(status);
579 } else if (WIFEXITED(status)) {
580 XBT_DEBUG("Child process is over");
587 } // namespace simgrid::mc