1 /* Copyright (c) 2014-2022. 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/remote/RemoteProcess.hpp"
10 #include "src/mc/sosp/Snapshot.hpp"
11 #include "xbt/file.hpp"
15 #include <libunwind-ptrace.h>
16 #include <sys/mman.h> // PROT_*
25 using simgrid::mc::remote;
27 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_process, mc, "MC process information");
34 static bool is_filtered_lib(const std::string& libname)
36 return libname != "libsimgrid";
39 static std::string get_lib_name(const std::string& pathname)
41 std::string map_basename = simgrid::xbt::Path(pathname).get_base_name();
44 size_t pos = map_basename.rfind(".so");
45 if (pos != std::string::npos) {
46 // strip the extension (matching regex "\.so.*$")
47 libname.assign(map_basename, 0, pos);
49 // strip the version suffix (matching regex "-[.0-9-]*$")
51 pos = libname.rfind('-');
52 if (pos == std::string::npos || libname.find_first_not_of(".0123456789", pos + 1) != std::string::npos)
61 static ssize_t pread_whole(int fd, void* buf, size_t count, off_t offset)
63 auto* buffer = static_cast<char*>(buf);
64 ssize_t real_count = count;
66 ssize_t res = pread(fd, buffer, count, offset);
73 else if (errno != EINTR) {
74 XBT_ERROR("pread_whole: %s", strerror(errno));
81 static ssize_t pwrite_whole(int fd, const void* buf, size_t count, off_t offset)
83 const auto* buffer = static_cast<const char*>(buf);
84 ssize_t real_count = count;
86 ssize_t res = pwrite(fd, buffer, count, offset);
93 else if (errno != EINTR) {
94 XBT_ERROR("pwrite_whole: %s", strerror(errno));
101 int open_vm(pid_t pid, int flags)
103 std::string buffer = "/proc/" + std::to_string(pid) + "/mem";
104 return open(buffer.c_str(), flags);
107 // ***** RemoteProcess
109 RemoteProcess::RemoteProcess(pid_t pid) : AddressSpace(this), pid_(pid), running_(true) {}
111 void RemoteProcess::init(xbt_mheap_t mmalloc_default_mdp, unsigned long* maxpid, xbt_dynar_t actors)
113 this->heap_address = remote(mmalloc_default_mdp);
114 this->maxpid_addr_ = remote(maxpid);
115 this->actors_addr_ = remote(actors);
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->smx_actors_infos.clear();
125 this->unw_addr_space = simgrid::mc::UnwindContext::createUnwindAddressSpace();
126 this->unw_underlying_addr_space = simgrid::unw::create_addr_space();
127 this->unw_underlying_context = simgrid::unw::create_context(this->unw_underlying_addr_space, this->pid_);
130 RemoteProcess::~RemoteProcess()
132 if (this->memory_file >= 0)
133 close(this->memory_file);
135 if (this->unw_underlying_addr_space != unw_local_addr_space) {
136 if (this->unw_underlying_addr_space)
137 unw_destroy_addr_space(this->unw_underlying_addr_space);
138 if (this->unw_underlying_context)
139 _UPT_destroy(this->unw_underlying_context);
142 unw_destroy_addr_space(this->unw_addr_space);
145 /** Refresh the information about the process
147 * Do not use directly, this is used by the getters when appropriate
148 * in order to have fresh data.
150 void RemoteProcess::refresh_heap()
152 // Read/dereference/refresh the std_heap pointer:
154 this->heap = std::make_unique<s_xbt_mheap_t>();
155 this->read(this->heap.get(), this->heap_address);
156 this->cache_flags_ |= RemoteProcess::cache_heap;
159 /** Refresh the information about the process
161 * Do not use directly, this is used by the getters when appropriate
162 * in order to have fresh data.
164 void RemoteProcess::refresh_malloc_info()
166 // Refresh process->heapinfo:
167 if (this->cache_flags_ & RemoteProcess::cache_malloc)
169 size_t count = this->heap->heaplimit + 1;
170 if (this->heap_info.size() < count)
171 this->heap_info.resize(count);
172 this->read_bytes(this->heap_info.data(), count * sizeof(malloc_info), remote(this->heap->heapinfo));
173 this->cache_flags_ |= RemoteProcess::cache_malloc;
176 /** @brief Finds the range of the different memory segments and binary paths */
177 void RemoteProcess::init_memory_map_info()
179 XBT_DEBUG("Get debug information ...");
180 this->maestro_stack_start_ = nullptr;
181 this->maestro_stack_end_ = nullptr;
182 this->object_infos.clear();
183 this->binary_info = nullptr;
185 std::vector<simgrid::xbt::VmMap> const& maps = this->memory_map_;
187 const char* current_name = nullptr;
189 for (size_t i = 0; i < maps.size(); i++) {
190 simgrid::xbt::VmMap const& reg = maps[i];
191 const char* pathname = maps[i].pathname.c_str();
194 if (maps[i].pathname.empty()) {
195 current_name = nullptr;
199 // [stack], [vvar], [vsyscall], [vdso] ...
200 if (pathname[0] == '[') {
201 if ((reg.prot & PROT_WRITE) && not memcmp(pathname, "[stack]", 7)) {
202 this->maestro_stack_start_ = remote(reg.start_addr);
203 this->maestro_stack_end_ = remote(reg.end_addr);
205 current_name = nullptr;
209 if (current_name && strcmp(current_name, pathname) == 0)
212 current_name = pathname;
213 if (not(reg.prot & PROT_READ) && (reg.prot & PROT_EXEC))
216 const bool is_executable = not i;
218 if (not is_executable) {
219 libname = get_lib_name(pathname);
220 if (is_filtered_lib(libname)) {
225 std::shared_ptr<simgrid::mc::ObjectInformation> info =
226 simgrid::mc::createObjectInformation(this->memory_map_, pathname);
227 this->object_infos.push_back(info);
229 this->binary_info = info;
232 xbt_assert(this->maestro_stack_start_, "Did not find maestro_stack_start");
233 xbt_assert(this->maestro_stack_end_, "Did not find maestro_stack_end");
235 XBT_DEBUG("Get debug information done !");
238 std::shared_ptr<simgrid::mc::ObjectInformation> RemoteProcess::find_object_info(RemotePtr<void> addr) const
240 for (auto const& object_info : this->object_infos)
241 if (addr.address() >= (std::uint64_t)object_info->start && addr.address() <= (std::uint64_t)object_info->end)
246 std::shared_ptr<ObjectInformation> RemoteProcess::find_object_info_exec(RemotePtr<void> addr) const
248 for (std::shared_ptr<ObjectInformation> const& info : this->object_infos)
249 if (addr.address() >= (std::uint64_t)info->start_exec && addr.address() <= (std::uint64_t)info->end_exec)
254 std::shared_ptr<ObjectInformation> RemoteProcess::find_object_info_rw(RemotePtr<void> addr) const
256 for (std::shared_ptr<ObjectInformation> const& info : this->object_infos)
257 if (addr.address() >= (std::uint64_t)info->start_rw && addr.address() <= (std::uint64_t)info->end_rw)
262 simgrid::mc::Frame* RemoteProcess::find_function(RemotePtr<void> ip) const
264 std::shared_ptr<simgrid::mc::ObjectInformation> info = this->find_object_info_exec(ip);
265 return info ? info->find_function((void*)ip.address()) : nullptr;
268 /** Find (one occurrence of) the named variable definition
270 const simgrid::mc::Variable* RemoteProcess::find_variable(const char* name) const
272 // First lookup the variable in the executable shared object.
273 // A global variable used directly by the executable code from a library
274 // is reinstantiated in the executable memory .data/.bss.
275 // We need to look up the variable in the executable first.
276 if (this->binary_info) {
277 std::shared_ptr<simgrid::mc::ObjectInformation> const& info = this->binary_info;
278 const simgrid::mc::Variable* var = info->find_variable(name);
283 for (std::shared_ptr<simgrid::mc::ObjectInformation> const& info : this->object_infos) {
284 const simgrid::mc::Variable* var = info->find_variable(name);
292 void RemoteProcess::read_variable(const char* name, void* target, size_t size) const
294 const simgrid::mc::Variable* var = this->find_variable(name);
295 xbt_assert(var, "Variable %s not found", name);
296 xbt_assert(var->address, "No simple location for this variable");
298 if (not var->type->full_type) // Try to resolve this type. The needed ObjectInfo was maybe (lazily) loaded recently
299 for (auto const& object_info : this->object_infos)
300 postProcessObjectInformation(this, object_info.get());
301 xbt_assert(var->type->full_type, "Partial type for %s (even after re-resolving types), cannot retrieve its size.",
303 xbt_assert((size_t)var->type->full_type->byte_size == size, "Unexpected size for %s (expected %zu, received %zu).",
304 name, size, (size_t)var->type->full_type->byte_size);
305 this->read_bytes(target, size, remote(var->address));
308 std::string RemoteProcess::read_string(RemotePtr<char> address) const
313 std::vector<char> res(128);
317 ssize_t c = pread(this->memory_file, res.data() + off, res.size() - off, (off_t)address.address() + off);
318 if (c == -1 && errno == EINTR)
320 xbt_assert(c > 0, "Could not read string from remote process");
322 const void* p = memchr(res.data() + off, '\0', c);
324 return std::string(res.data());
327 if (off == (off_t)res.size())
328 res.resize(res.size() * 2);
332 void* RemoteProcess::read_bytes(void* buffer, std::size_t size, RemotePtr<void> address, ReadOptions /*options*/) const
334 xbt_assert(pread_whole(this->memory_file, buffer, size, (size_t)address.address()) != -1,
335 "Read at %p from process %lli failed", (void*)address.address(), (long long)this->pid_);
339 /** Write data to a process memory
341 * @param buffer local memory address (source)
342 * @param len data size
343 * @param address target process memory address (target)
345 void RemoteProcess::write_bytes(const void* buffer, size_t len, RemotePtr<void> address) const
347 xbt_assert(pwrite_whole(this->memory_file, buffer, len, (size_t)address.address()) != -1,
348 "Write to process %lli failed", (long long)this->pid_);
351 static void zero_buffer_init(const void** zero_buffer, size_t zero_buffer_size)
353 int fd = open("/dev/zero", O_RDONLY);
354 xbt_assert(fd >= 0, "Could not open /dev/zero");
355 *zero_buffer = mmap(nullptr, zero_buffer_size, PROT_READ, MAP_SHARED, fd, 0);
356 xbt_assert(*zero_buffer != MAP_FAILED, "Could not map the zero buffer");
360 void RemoteProcess::clear_bytes(RemotePtr<void> address, size_t len) const
362 static constexpr size_t zero_buffer_size = 10 * 4096;
363 static const void* zero_buffer;
364 static std::once_flag zero_buffer_flag;
366 std::call_once(zero_buffer_flag, zero_buffer_init, &zero_buffer, zero_buffer_size);
368 size_t s = len > zero_buffer_size ? zero_buffer_size : len;
369 this->write_bytes(zero_buffer, s, address);
370 address = remote((char*)address.address() + s);
375 void RemoteProcess::ignore_region(std::uint64_t addr, std::size_t size)
377 IgnoredRegion region;
381 auto pos = std::lower_bound(ignored_regions_.begin(), ignored_regions_.end(), region,
382 [](auto const& reg1, auto const& reg2) {
383 return reg1.addr < reg2.addr || (reg1.addr == reg2.addr && reg1.size < reg2.size);
385 if (pos == ignored_regions_.end() || pos->addr != addr || pos->size != size)
386 ignored_regions_.insert(pos, region);
389 void RemoteProcess::ignore_heap(IgnoredHeapRegion const& region)
391 // Binary search the position of insertion:
392 auto pos = std::lower_bound(ignored_heap_.begin(), ignored_heap_.end(), region.address,
393 [](auto const& reg, auto const* addr) { return reg.address < addr; });
394 if (pos == ignored_heap_.end() || pos->address != region.address) {
396 ignored_heap_.insert(pos, region);
400 void RemoteProcess::unignore_heap(void* address, size_t size)
403 auto pos = std::lower_bound(ignored_heap_.begin(), ignored_heap_.end(), address,
404 [](auto const& reg, auto const* addr) { return reg.address < addr; });
405 if (pos != ignored_heap_.end() && static_cast<char*>(pos->address) <= static_cast<char*>(address) + size)
406 ignored_heap_.erase(pos);
409 void RemoteProcess::ignore_local_variable(const char* var_name, const char* frame_name) const
411 if (frame_name != nullptr && strcmp(frame_name, "*") == 0)
412 frame_name = nullptr;
413 for (std::shared_ptr<simgrid::mc::ObjectInformation> const& info : this->object_infos)
414 info->remove_local_variable(var_name, frame_name);
417 std::vector<simgrid::mc::ActorInformation>& RemoteProcess::actors()
419 this->refresh_simix();
420 return smx_actors_infos;
423 void RemoteProcess::dump_stack() const
425 unw_addr_space_t as = unw_create_addr_space(&_UPT_accessors, BYTE_ORDER);
427 XBT_ERROR("Could not initialize ptrace address space");
431 void* context = _UPT_create(this->pid_);
432 if (context == nullptr) {
433 unw_destroy_addr_space(as);
434 XBT_ERROR("Could not initialize ptrace context");
439 if (unw_init_remote(&cursor, as, context) != 0) {
440 _UPT_destroy(context);
441 unw_destroy_addr_space(as);
442 XBT_ERROR("Could not initialize ptrace cursor");
446 simgrid::mc::dumpStack(stderr, &cursor);
448 _UPT_destroy(context);
449 unw_destroy_addr_space(as);
452 } // namespace simgrid