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/sosp/Snapshot.hpp"
11 #include "xbt/file.hpp"
15 #include <libunwind-ptrace.h>
16 #include <sys/mman.h> // PROT_*
24 #include <string_view>
26 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_process, mc, "MC process information");
28 namespace simgrid::mc {
32 static bool is_filtered_lib(std::string_view libname)
34 return libname != "libsimgrid";
37 static std::string get_lib_name(const std::string& pathname)
39 std::string map_basename = simgrid::xbt::Path(pathname).get_base_name();
42 if (size_t pos = map_basename.rfind(".so"); pos != std::string::npos) {
43 // strip the extension (matching regex "\.so.*$")
44 libname.assign(map_basename, 0, pos);
46 // strip the version suffix (matching regex "-[.0-9-]*$")
48 pos = libname.rfind('-');
49 if (pos == std::string::npos || libname.find_first_not_of(".0123456789", pos + 1) != std::string::npos)
58 static ssize_t pread_whole(int fd, void* buf, size_t count, off_t offset)
60 auto* buffer = static_cast<char*>(buf);
61 ssize_t real_count = count;
63 ssize_t res = pread(fd, buffer, count, offset);
70 else if (errno != EINTR) {
71 XBT_ERROR("pread_whole: %s", strerror(errno));
78 static ssize_t pwrite_whole(int fd, const void* buf, size_t count, off_t offset)
80 const auto* buffer = static_cast<const char*>(buf);
81 ssize_t real_count = count;
83 ssize_t res = pwrite(fd, buffer, count, offset);
90 else if (errno != EINTR) {
91 XBT_ERROR("pwrite_whole: %s", strerror(errno));
98 int open_vm(pid_t pid, int flags)
100 std::string buffer = "/proc/" + std::to_string(pid) + "/mem";
101 return open(buffer.c_str(), flags);
104 // ***** RemoteProcessMemory
106 RemoteProcessMemory::RemoteProcessMemory(pid_t pid) : AddressSpace(this), pid_(pid), running_(true) {}
108 void RemoteProcessMemory::init(xbt_mheap_t mmalloc_default_mdp)
110 this->heap_address = remote(mmalloc_default_mdp);
112 this->memory_map_ = simgrid::xbt::get_memory_map(this->pid_);
113 this->init_memory_map_info();
115 int fd = open_vm(this->pid_, O_RDWR);
116 xbt_assert(fd >= 0, "Could not open file for process virtual address space");
117 this->memory_file = fd;
119 this->unw_addr_space = simgrid::mc::UnwindContext::createUnwindAddressSpace();
120 this->unw_underlying_addr_space = simgrid::unw::create_addr_space();
121 this->unw_underlying_context = simgrid::unw::create_context(this->unw_underlying_addr_space, this->pid_);
123 auto ignored_local_variables = {
124 std::make_pair("e", "*"),
125 std::make_pair("_log_ev", "*"),
127 /* Ignore local variable about time used for tracing */
128 std::make_pair("start_time", "*"),
130 for (auto const& [var, frame] : ignored_local_variables)
131 ignore_local_variable(var, frame);
133 ignore_global_variable("counter"); // Static variable used for tracing
136 RemoteProcessMemory::~RemoteProcessMemory()
138 if (this->memory_file >= 0)
139 close(this->memory_file);
141 if (this->unw_underlying_addr_space != unw_local_addr_space) {
142 if (this->unw_underlying_addr_space)
143 unw_destroy_addr_space(this->unw_underlying_addr_space);
144 if (this->unw_underlying_context)
145 _UPT_destroy(this->unw_underlying_context);
148 unw_destroy_addr_space(this->unw_addr_space);
151 /** Refresh the information about the process
153 * Do not use directly, this is used by the getters when appropriate
154 * in order to have fresh data.
156 void RemoteProcessMemory::refresh_heap()
158 // Read/dereference/refresh the std_heap pointer:
159 this->read(this->heap.get(), this->heap_address);
160 this->cache_flags_ |= RemoteProcessMemory::cache_heap;
163 /** Refresh the information about the process
165 * Do not use directly, this is used by the getters when appropriate
166 * in order to have fresh data.
168 void RemoteProcessMemory::refresh_malloc_info()
170 // Refresh process->heapinfo:
171 if (this->cache_flags_ & RemoteProcessMemory::cache_malloc)
173 size_t count = this->heap->heaplimit + 1;
174 if (this->heap_info.size() < count)
175 this->heap_info.resize(count);
176 this->read_bytes(this->heap_info.data(), count * sizeof(malloc_info), remote(this->heap->heapinfo));
177 this->cache_flags_ |= RemoteProcessMemory::cache_malloc;
179 std::size_t RemoteProcessMemory::get_remote_heap_bytes()
181 return mmalloc_get_bytes_used_remote(get_heap()->heaplimit, get_malloc_info());
184 /** @brief Finds the range of the different memory segments and binary paths */
185 void RemoteProcessMemory::init_memory_map_info()
187 XBT_DEBUG("Get debug information ...");
188 this->maestro_stack_start_ = nullptr;
189 this->maestro_stack_end_ = nullptr;
190 this->object_infos.clear();
191 this->binary_info = nullptr;
193 std::vector<simgrid::xbt::VmMap> const& maps = this->memory_map_;
195 const char* current_name = nullptr;
197 for (size_t i = 0; i < maps.size(); i++) {
198 simgrid::xbt::VmMap const& reg = maps[i];
199 const char* pathname = maps[i].pathname.c_str();
202 if (maps[i].pathname.empty()) {
203 current_name = nullptr;
207 // [stack], [vvar], [vsyscall], [vdso] ...
208 if (pathname[0] == '[') {
209 if ((reg.prot & PROT_WRITE) && not memcmp(pathname, "[stack]", 7)) {
210 this->maestro_stack_start_ = remote(reg.start_addr);
211 this->maestro_stack_end_ = remote(reg.end_addr);
213 current_name = nullptr;
217 if (current_name && strcmp(current_name, pathname) == 0)
220 current_name = pathname;
221 if (not(reg.prot & PROT_READ) && (reg.prot & PROT_EXEC))
224 const bool is_executable = not i;
226 if (not is_executable) {
227 libname = get_lib_name(pathname);
228 if (is_filtered_lib(libname)) {
233 std::shared_ptr<simgrid::mc::ObjectInformation> info =
234 simgrid::mc::createObjectInformation(this->memory_map_, pathname);
235 this->object_infos.push_back(info);
237 this->binary_info = info;
240 xbt_assert(this->maestro_stack_start_, "Did not find maestro_stack_start");
241 xbt_assert(this->maestro_stack_end_, "Did not find maestro_stack_end");
243 XBT_DEBUG("Get debug information done !");
246 std::shared_ptr<simgrid::mc::ObjectInformation> RemoteProcessMemory::find_object_info(RemotePtr<void> addr) const
248 for (auto const& object_info : this->object_infos)
249 if (addr.address() >= (std::uint64_t)object_info->start && addr.address() <= (std::uint64_t)object_info->end)
254 std::shared_ptr<ObjectInformation> RemoteProcessMemory::find_object_info_exec(RemotePtr<void> addr) const
256 for (std::shared_ptr<ObjectInformation> const& info : this->object_infos)
257 if (addr.address() >= (std::uint64_t)info->start_exec && addr.address() <= (std::uint64_t)info->end_exec)
262 std::shared_ptr<ObjectInformation> RemoteProcessMemory::find_object_info_rw(RemotePtr<void> addr) const
264 for (std::shared_ptr<ObjectInformation> const& info : this->object_infos)
265 if (addr.address() >= (std::uint64_t)info->start_rw && addr.address() <= (std::uint64_t)info->end_rw)
270 simgrid::mc::Frame* RemoteProcessMemory::find_function(RemotePtr<void> ip) const
272 std::shared_ptr<simgrid::mc::ObjectInformation> info = this->find_object_info_exec(ip);
273 return info ? info->find_function((void*)ip.address()) : nullptr;
276 /** Find (one occurrence of) the named variable definition
278 const simgrid::mc::Variable* RemoteProcessMemory::find_variable(const char* name) const
280 // First lookup the variable in the executable shared object.
281 // A global variable used directly by the executable code from a library
282 // is reinstantiated in the executable memory .data/.bss.
283 // We need to look up the variable in the executable first.
284 if (this->binary_info) {
285 std::shared_ptr<simgrid::mc::ObjectInformation> const& info = this->binary_info;
286 const simgrid::mc::Variable* var = info->find_variable(name);
291 for (std::shared_ptr<simgrid::mc::ObjectInformation> const& info : this->object_infos) {
292 const simgrid::mc::Variable* var = info->find_variable(name);
300 void RemoteProcessMemory::read_variable(const char* name, void* target, size_t size) const
302 const simgrid::mc::Variable* var = this->find_variable(name);
303 xbt_assert(var, "Variable %s not found", name);
304 xbt_assert(var->address, "No simple location for this variable");
306 if (not var->type->full_type) // Try to resolve this type. The needed ObjectInfo was maybe (lazily) loaded recently
307 for (auto const& object_info : this->object_infos)
308 postProcessObjectInformation(this, object_info.get());
309 xbt_assert(var->type->full_type, "Partial type for %s (even after re-resolving types), cannot retrieve its size.",
311 xbt_assert((size_t)var->type->full_type->byte_size == size, "Unexpected size for %s (expected %zu, received %zu).",
312 name, size, (size_t)var->type->full_type->byte_size);
313 this->read_bytes(target, size, remote(var->address));
316 std::string RemoteProcessMemory::read_string(RemotePtr<char> address) const
321 std::vector<char> res(128);
325 ssize_t c = pread(this->memory_file, res.data() + off, res.size() - off, (off_t)address.address() + off);
326 if (c == -1 && errno == EINTR)
328 xbt_assert(c > 0, "Could not read string from remote process");
330 if (memchr(res.data() + off, '\0', c))
334 if (off == (off_t)res.size())
335 res.resize(res.size() * 2);
339 void* RemoteProcessMemory::read_bytes(void* buffer, std::size_t size, RemotePtr<void> address,
340 ReadOptions /*options*/) const
342 xbt_assert(pread_whole(this->memory_file, buffer, size, (size_t)address.address()) != -1,
343 "Read at %p from process %lli failed", (void*)address.address(), (long long)this->pid_);
347 /** Write data to a process memory
349 * @param buffer local memory address (source)
350 * @param len data size
351 * @param address target process memory address (target)
353 void RemoteProcessMemory::write_bytes(const void* buffer, size_t len, RemotePtr<void> address) const
355 xbt_assert(pwrite_whole(this->memory_file, buffer, len, (size_t)address.address()) != -1,
356 "Write to process %lli failed", (long long)this->pid_);
359 static void zero_buffer_init(const void** zero_buffer, size_t zero_buffer_size)
361 int fd = open("/dev/zero", O_RDONLY);
362 xbt_assert(fd >= 0, "Could not open /dev/zero");
363 *zero_buffer = mmap(nullptr, zero_buffer_size, PROT_READ, MAP_SHARED, fd, 0);
364 xbt_assert(*zero_buffer != MAP_FAILED, "Could not map the zero buffer");
368 void RemoteProcessMemory::clear_bytes(RemotePtr<void> address, size_t len) const
370 static constexpr size_t zero_buffer_size = 10 * 4096;
371 static const void* zero_buffer;
372 static std::once_flag zero_buffer_flag;
374 std::call_once(zero_buffer_flag, zero_buffer_init, &zero_buffer, zero_buffer_size);
376 size_t s = len > zero_buffer_size ? zero_buffer_size : len;
377 this->write_bytes(zero_buffer, s, address);
378 address = remote((char*)address.address() + s);
383 void RemoteProcessMemory::ignore_region(std::uint64_t addr, std::size_t size)
385 IgnoredRegion region;
389 auto pos = std::lower_bound(ignored_regions_.begin(), ignored_regions_.end(), region,
390 [](auto const& reg1, auto const& reg2) {
391 return reg1.addr < reg2.addr || (reg1.addr == reg2.addr && reg1.size < reg2.size);
393 if (pos == ignored_regions_.end() || pos->addr != addr || pos->size != size)
394 ignored_regions_.insert(pos, region);
397 void RemoteProcessMemory::ignore_heap(IgnoredHeapRegion const& region)
399 // Binary search the position of insertion:
400 auto pos = std::lower_bound(ignored_heap_.begin(), ignored_heap_.end(), region.address,
401 [](auto const& reg, auto const* addr) { return reg.address < addr; });
402 if (pos == ignored_heap_.end() || pos->address != region.address) {
404 ignored_heap_.insert(pos, region);
408 void RemoteProcessMemory::unignore_heap(void* address, size_t size)
411 auto pos = std::lower_bound(ignored_heap_.begin(), ignored_heap_.end(), address,
412 [](auto const& reg, auto const* addr) { return reg.address < addr; });
413 if (pos != ignored_heap_.end() && static_cast<char*>(pos->address) <= static_cast<char*>(address) + size)
414 ignored_heap_.erase(pos);
417 void RemoteProcessMemory::ignore_local_variable(const char* var_name, const char* frame_name) const
419 if (frame_name != nullptr && strcmp(frame_name, "*") == 0)
420 frame_name = nullptr;
421 for (std::shared_ptr<simgrid::mc::ObjectInformation> const& info : this->object_infos)
422 info->remove_local_variable(var_name, frame_name);
425 void RemoteProcessMemory::dump_stack() const
427 unw_addr_space_t as = unw_create_addr_space(&_UPT_accessors, BYTE_ORDER);
429 XBT_ERROR("Could not initialize ptrace address space");
433 void* context = _UPT_create(this->pid_);
434 if (context == nullptr) {
435 unw_destroy_addr_space(as);
436 XBT_ERROR("Could not initialize ptrace context");
441 if (unw_init_remote(&cursor, as, context) != 0) {
442 _UPT_destroy(context);
443 unw_destroy_addr_space(as);
444 XBT_ERROR("Could not initialize ptrace cursor");
448 simgrid::mc::dumpStack(stderr, &cursor);
450 _UPT_destroy(context);
451 unw_destroy_addr_space(as);
453 } // namespace simgrid::mc