1 /* Copyright (c) 2008-2015. The SimGrid Team.
2 * All rights reserved. */
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. */
14 #include "src/internal_config.h"
15 #include "src/mc/mc_private.h"
16 #include "xbt/module.h"
17 #include <xbt/mmalloc.h>
18 #include <xbt/memory.hpp>
19 #include "src/smpi/private.h"
21 #include "src/xbt/mmalloc/mmprivate.h"
23 #include "src/simix/smx_private.h"
25 #include <libunwind.h>
28 #include "src/mc/mc_private.h"
31 #include "src/mc/mc_snapshot.h"
32 #include "src/mc/mc_mmu.h"
33 #include "src/mc/mc_unw.h"
34 #include "src/mc/mc_protocol.h"
35 #include "src/mc/mc_smx.h"
36 #include "mc_hash.hpp"
38 #include "src/mc/RegionSnapshot.hpp"
39 #include "src/mc/ObjectInformation.hpp"
40 #include "src/mc/Frame.hpp"
41 #include "src/mc/Variable.hpp"
43 using simgrid::mc::remote;
47 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_checkpoint, mc,
48 "Logging specific to mc_checkpoint");
55 /************************************ Free functions **************************************/
56 /*****************************************************************************************/
58 /** @brief Restore a region from a snapshot
60 * @param reg Target region
62 static void restore(mc_mem_region_t region)
64 switch(region->storage_type()) {
65 case simgrid::mc::StorageType::NoData:
67 xbt_die("Storage type not supported");
70 case simgrid::mc::StorageType::Flat:
71 mc_model_checker->process().write_bytes(region->flat_data().get(),
72 region->size(), region->permanent_address());
75 case simgrid::mc::StorageType::Chunked:
76 mc_region_restore_sparse(&mc_model_checker->process(), region);
79 case simgrid::mc::StorageType::Privatized:
80 for (auto& p : region->privatized_data())
87 RegionSnapshot privatized_region(
88 RegionType region_type, void *start_addr, void* permanent_addr,
89 std::size_t size, const RegionSnapshot* ref_region
92 size_t process_count = MC_smpi_process_count();
94 // Read smpi_privatisation_regions from MCed:
95 smpi_privatisation_region_t remote_smpi_privatisation_regions;
96 mc_model_checker->process().read_variable(
97 "smpi_privatisation_regions",
98 &remote_smpi_privatisation_regions, sizeof(remote_smpi_privatisation_regions));
99 s_smpi_privatisation_region_t privatisation_regions[process_count];
100 mc_model_checker->process().read_bytes(
101 &privatisation_regions, sizeof(privatisation_regions),
102 remote(remote_smpi_privatisation_regions));
104 std::vector<simgrid::mc::RegionSnapshot> data;
105 data.reserve(process_count);
106 for (size_t i = 0; i < process_count; i++) {
107 const simgrid::mc::RegionSnapshot* ref_privatized_region = nullptr;
108 if (ref_region && ref_region->storage_type() == StorageType::Privatized)
109 ref_privatized_region = &ref_region->privatized_data()[i];
110 data.push_back(simgrid::mc::region(region_type, start_addr,
111 privatisation_regions[i].address, size, ref_privatized_region));
114 simgrid::mc::RegionSnapshot region = simgrid::mc::RegionSnapshot(
115 region_type, start_addr, permanent_addr, size);
116 region.privatized_data(std::move(data));
117 return std::move(region);
122 void add_region(int index, mc_snapshot_t snapshot,
123 simgrid::mc::RegionType type,
124 simgrid::mc::ObjectInformation* object_info,
125 void *start_addr, void* permanent_addr,
128 if (type == simgrid::mc::RegionType::Data)
129 xbt_assert(object_info, "Missing object info for object.");
130 else if (type == simgrid::mc::RegionType::Heap)
131 xbt_assert(!object_info, "Unexpected object info for heap region.");
133 simgrid::mc::RegionSnapshot const* ref_region = nullptr;
134 if (mc_model_checker->parent_snapshot_)
135 ref_region = mc_model_checker->parent_snapshot_->snapshot_regions[index].get();
137 simgrid::mc::RegionSnapshot region;
139 const bool privatization_aware = object_info
140 && mc_model_checker->process().privatized(*object_info);
141 if (privatization_aware && MC_smpi_process_count())
142 region = simgrid::mc::privatized_region(
143 type, start_addr, permanent_addr, size, ref_region);
146 region = simgrid::mc::region(type, start_addr, permanent_addr, size, ref_region);
148 region.object_info(object_info);
149 snapshot->snapshot_regions[index]
150 = std::unique_ptr<simgrid::mc::RegionSnapshot>(
151 new simgrid::mc::RegionSnapshot(std::move(region)));
155 static void get_memory_regions(simgrid::mc::Process* process, mc_snapshot_t snapshot)
157 const size_t n = process->object_infos.size();
158 snapshot->snapshot_regions.resize(n + 1);
160 for (auto const& object_info : process->object_infos)
161 add_region(i++, snapshot, simgrid::mc::RegionType::Data,
163 object_info->start_rw, object_info->start_rw,
164 object_info->end_rw - object_info->start_rw);
166 xbt_mheap_t heap = process->get_heap();
167 void *start_heap = heap->base;
168 void *end_heap = heap->breakval;
170 add_region(n, snapshot, simgrid::mc::RegionType::Heap, nullptr,
171 start_heap, start_heap,
172 (char *) end_heap - (char *) start_heap);
173 snapshot->heap_bytes_used = mmalloc_get_bytes_used_remote(
175 process->get_malloc_info());
178 if (mc_model_checker->process().privatized() && MC_smpi_process_count())
179 // snapshot->privatization_index = smpi_loaded_page
180 mc_model_checker->process().read_variable(
181 "smpi_loaded_page", &snapshot->privatization_index,
182 sizeof(snapshot->privatization_index));
185 snapshot->privatization_index = simgrid::mc::ProcessIndexMissing;
188 /** \brief Fills the position of the segments (executable, read-only, read/write).
190 * `dl_iterate_phdr` would be more robust but would not work in cross-process.
192 void find_object_address(
193 std::vector<simgrid::xbt::VmMap> const& maps,
194 simgrid::mc::ObjectInformation* result)
196 char* name = xbt_basename(result->file_name.c_str());
198 for (size_t i = 0; i < maps.size(); ++i) {
199 simgrid::xbt::VmMap const& reg = maps[i];
200 if (maps[i].pathname.empty())
202 char* map_basename = xbt_basename(maps[i].pathname.c_str());
203 if (strcmp(name, map_basename) != 0) {
208 if ((reg.prot & PROT_WRITE)) {
209 xbt_assert(!result->start_rw,
210 "Multiple read-write segments for %s, not supported",
211 maps[i].pathname.c_str());
212 result->start_rw = (char*) reg.start_addr;
213 result->end_rw = (char*) reg.end_addr;
214 // .bss is usually after the .data:
215 simgrid::xbt::VmMap const& next = maps[i + 1];
216 if (next.pathname.empty() && (next.prot & PROT_WRITE)
217 && next.start_addr == reg.end_addr)
218 result->end_rw = (char*) maps[i + 1].end_addr;
219 } else if ((reg.prot & PROT_READ) && (reg.prot & PROT_EXEC)) {
220 xbt_assert(!result->start_exec,
221 "Multiple executable segments for %s, not supported",
222 maps[i].pathname.c_str());
223 result->start_exec = (char*) reg.start_addr;
224 result->end_exec = (char*) reg.end_addr;
225 } else if ((reg.prot & PROT_READ) && !(reg.prot & PROT_EXEC)) {
226 xbt_assert(!result->start_ro,
227 "Multiple read only segments for %s, not supported",
228 maps[i].pathname.c_str());
229 result->start_ro = (char*) reg.start_addr;
230 result->end_ro = (char*) reg.end_addr;
234 result->start = result->start_rw;
235 if ((const void*) result->start_ro > result->start)
236 result->start = result->start_ro;
237 if ((const void*) result->start_exec > result->start)
238 result->start = result->start_exec;
240 result->end = result->end_rw;
241 if (result->end_ro && (const void*) result->end_ro < result->end)
242 result->end = result->end_ro;
243 if (result->end_exec && (const void*) result->end_exec > result->end)
244 result->end = result->end_exec;
246 xbt_assert(result->start_rw);
247 xbt_assert(result->start_exec);
252 /************************************* Take Snapshot ************************************/
253 /****************************************************************************************/
255 /** \brief Checks whether the variable is in scope for a given IP.
257 * A variable may be defined only from a given value of IP.
259 * \param var Variable description
260 * \param frame Scope description
261 * \param ip Instruction pointer
262 * \return true if the variable is valid
264 static bool valid_variable(simgrid::mc::Variable* var,
265 simgrid::mc::Frame* scope,
268 // The variable is not yet valid:
269 if (scope->range.begin() + var->start_scope > (std::uint64_t) ip)
275 static void fill_local_variables_values(mc_stack_frame_t stack_frame,
276 simgrid::mc::Frame* scope,
278 std::vector<s_local_variable>& result)
280 simgrid::mc::Process* process = &mc_model_checker->process();
282 if (!scope->range.contain(stack_frame->ip))
285 for(simgrid::mc::Variable& current_variable :
288 if (!valid_variable(¤t_variable, scope, (void *) stack_frame->ip))
292 // FIXME, get rid of `region_type`
293 if ((long) stack_frame->ip > (long) process->libsimgrid_info->start_exec)
298 s_local_variable_t new_var;
299 new_var.subprogram = stack_frame->frame;
300 new_var.ip = stack_frame->ip;
301 new_var.name = current_variable.name;
302 new_var.type = current_variable.type;
303 new_var.region = region_type;
304 new_var.address = nullptr;
306 if (current_variable.address != nullptr)
307 new_var.address = current_variable.address;
308 else if (!current_variable.location_list.empty()) {
309 simgrid::dwarf::Location location =
310 simgrid::dwarf::resolve(
311 current_variable.location_list,
312 current_variable.object_info,
313 &(stack_frame->unw_cursor),
314 (void *) stack_frame->frame_base,
315 &mc_model_checker->process(), process_index);
317 if (!location.in_memory())
318 xbt_die("Cannot handle non-address variable");
319 new_var.address = location.address();
322 xbt_die("No address");
324 result.push_back(std::move(new_var));
327 // Recursive processing of nested scopes:
328 for(simgrid::mc::Frame& nested_scope : scope->scopes)
329 fill_local_variables_values(
330 stack_frame, &nested_scope, process_index, result);
333 static std::vector<s_local_variable> get_local_variables_values(
334 std::vector<s_mc_stack_frame_t>& stack_frames, int process_index)
336 std::vector<s_local_variable> variables;
337 for (s_mc_stack_frame_t& stack_frame : stack_frames)
338 fill_local_variables_values(&stack_frame, stack_frame.frame, process_index, variables);
339 return std::move(variables);
342 static std::vector<s_mc_stack_frame_t> unwind_stack_frames(mc_unw_context_t stack_context)
344 simgrid::mc::Process* process = &mc_model_checker->process();
345 std::vector<s_mc_stack_frame_t> result;
349 // TODO, check condition check (unw_init_local==0 means end of frame)
350 if (mc_unw_init_cursor(&c, stack_context) != 0)
351 xbt_die("Could not initialize stack unwinding");
355 s_mc_stack_frame_t stack_frame;
357 stack_frame.unw_cursor = c;
361 unw_get_reg(&c, UNW_REG_IP, &ip);
362 unw_get_reg(&c, UNW_REG_SP, &sp);
367 // TODO, use real addresses in frame_t instead of fixing it here
369 simgrid::mc::Frame* frame = process->find_function(remote(ip));
370 stack_frame.frame = frame;
373 stack_frame.frame_name = frame->name;
374 stack_frame.frame_base =
375 (unw_word_t) frame->frame_base(c);
377 stack_frame.frame_base = 0;
378 stack_frame.frame_name = std::string();
381 result.push_back(std::move(stack_frame));
383 /* Stop before context switch with maestro */
384 if (frame != nullptr &&
385 frame->name == "smx_ctx_sysv_wrapper")
388 int ret = unw_step(&c);
390 xbt_die("Unexpected end of stack.");
392 xbt_die("Error while unwinding stack");
395 if (result.empty()) {
396 XBT_INFO("unw_init_local failed");
400 return std::move(result);
403 static std::vector<s_mc_snapshot_stack_t> take_snapshot_stacks(mc_snapshot_t * snapshot)
405 std::vector<s_mc_snapshot_stack_t> res;
407 for (auto const& stack : mc_model_checker->process().stack_areas()) {
408 s_mc_snapshot_stack_t st;
410 // Read the context from remote process:
411 unw_context_t context;
412 mc_model_checker->process().read_bytes(
413 &context, sizeof(context), remote(stack.context));
415 if (mc_unw_init_context(&st.context, &mc_model_checker->process(),
417 xbt_die("Could not initialise the libunwind context.");
419 st.stack_frames = unwind_stack_frames(&st.context);
420 st.local_variables = get_local_variables_values(st.stack_frames, stack.process_index);
421 st.process_index = stack.process_index;
423 unw_word_t sp = st.stack_frames[0].sp;
425 res.push_back(std::move(st));
428 (char*) stack.address + stack.size - (char*) sp;
429 (*snapshot)->stack_sizes.push_back(stack_size);
432 return std::move(res);
436 static void snapshot_handle_ignore(mc_snapshot_t snapshot)
438 xbt_assert(snapshot->process());
441 for (auto const& region : mc_model_checker->process().ignored_regions()) {
442 s_mc_snapshot_ignored_data_t ignored_data;
443 ignored_data.start = (void*)region.addr;
444 ignored_data.data.resize(region.size);
445 // TODO, we should do this once per privatization segment:
446 snapshot->process()->read_bytes(
447 ignored_data.data.data(), region.size, remote(region.addr),
448 simgrid::mc::ProcessIndexDisabled);
449 snapshot->ignored_data.push_back(std::move(ignored_data));
453 for(auto const& region : mc_model_checker->process().ignored_regions())
454 snapshot->process()->clear_bytes(remote(region.addr), region.size);
458 static void snapshot_ignore_restore(mc_snapshot_t snapshot)
460 for (auto const& ignored_data : snapshot->ignored_data)
461 snapshot->process()->write_bytes(
462 ignored_data.data.data(), ignored_data.data.size(),
463 remote(ignored_data.start));
466 static std::vector<s_fd_infos_t> get_current_fds(pid_t pid)
468 const size_t fd_dir_path_size = 20;
469 char fd_dir_path[fd_dir_path_size];
470 int res = snprintf(fd_dir_path, fd_dir_path_size,
471 "/proc/%lli/fd", (long long int) pid);
472 xbt_assert(res >= 0);
473 if ((size_t) res > fd_dir_path_size)
474 xbt_die("Unexpected buffer is too small for fd_dir_path");
476 DIR* fd_dir = opendir(fd_dir_path);
477 if (fd_dir == nullptr)
478 xbt_die("Cannot open directory '/proc/self/fd'\n");
480 std::vector<s_fd_infos_t> fds;
482 struct dirent* fd_number;
483 while ((fd_number = readdir(fd_dir))) {
485 int fd_value = xbt_str_parse_int(fd_number->d_name, "Found a non-numerical FD: %s. Freaking out!");
490 const size_t source_size = 25;
492 int res = snprintf(source, source_size, "/proc/%lli/fd/%s",
493 (long long int) pid, fd_number->d_name);
494 xbt_assert(res >= 0);
495 if ((size_t) res > source_size)
496 xbt_die("Unexpected buffer is too small for fd %s", fd_number->d_name);
498 const size_t link_size = 200;
500 res = readlink(source, link, link_size);
503 xbt_die("Could not read link for %s", source);
505 xbt_die("Buffer to small for link of %s", source);
510 if(smpi_is_privatisation_file(link))
514 // This is (probably) the DIR* we are reading:
515 // TODO, read all the file entries at once and close the DIR.*
516 if(strcmp(fd_dir_path, link) == 0)
519 // We don't handle them.
520 // It does not mean we should silently ignore them however.
521 if (strncmp(link, "pipe:", 5) == 0 || strncmp(link, "socket:", 7) == 0)
524 // If dot_output enabled, do not handle the corresponding file
525 if (dot_output != nullptr) {
526 char* link_basename = xbt_basename(link);
527 if (strcmp(link_basename, _sg_mc_dot_output_file) == 0) {
534 // This is probably a shared memory used by lttng-ust:
535 if(strncmp("/dev/shm/ust-shm-tmp-", link, 21)==0)
538 // Add an entry for this FD in the snapshot:
540 fd.filename = std::string(link);
541 fd.number = fd_value;
542 fd.flags = fcntl(fd_value, F_GETFL) | fcntl(fd_value, F_GETFD) ;
543 fd.current_position = lseek(fd_value, 0, SEEK_CUR);
544 fds.push_back(std::move(fd));
548 return std::move(fds);
551 mc_snapshot_t take_snapshot(int num_state)
553 XBT_DEBUG("Taking snapshot %i", num_state);
555 simgrid::mc::Process* mc_process = &mc_model_checker->process();
557 mc_snapshot_t snapshot = new simgrid::mc::Snapshot(mc_process);
559 snapshot->num_state = num_state;
561 for (auto& p : mc_model_checker->process().simix_processes())
562 snapshot->enabled_processes.insert(p.copy.pid);
564 snapshot_handle_ignore(snapshot);
566 if (_sg_mc_snapshot_fds)
567 snapshot->current_fds = get_current_fds(mc_model_checker->process().pid());
569 const bool use_soft_dirty = _sg_mc_sparse_checkpoint && _sg_mc_soft_dirty;
571 /* Save the std heap and the writable mapped pages of libsimgrid and binary */
572 get_memory_regions(mc_process, snapshot);
574 mc_process->reset_soft_dirty();
576 snapshot->to_ignore = mc_model_checker->process().ignored_heap();
578 if (_sg_mc_visited > 0 || strcmp(_sg_mc_property_file, "")) {
580 take_snapshot_stacks(&snapshot);
582 snapshot->hash = simgrid::mc::hash(*snapshot);
588 snapshot_ignore_restore(snapshot);
590 mc_model_checker->parent_snapshot_ = snapshot;
595 void restore_snapshot_regions(mc_snapshot_t snapshot)
597 for(std::unique_ptr<s_mc_mem_region_t> const& region : snapshot->snapshot_regions) {
598 // For privatized, variables we decided it was not necessary to take the snapshot:
600 restore(region.get());
604 // TODO, send a message to implement this in the MCed process
605 if(snapshot->privatization_index >= 0) {
606 // Fix the privatization mmap:
607 s_mc_restore_message message;
608 message.type = MC_MESSAGE_RESTORE;
609 message.index = snapshot->privatization_index;
610 mc_model_checker->process().send_message(message);
616 void restore_snapshot_fds(mc_snapshot_t snapshot)
618 if (mc_mode == MC_MODE_SERVER)
619 xbt_die("FD snapshot not implemented in client/server mode.");
621 for (auto const& fd : snapshot->current_fds) {
623 int new_fd = open(fd.filename.c_str(), fd.flags);
625 xbt_die("Could not reopen the file %s fo restoring the file descriptor",
626 fd.filename.c_str());
627 if (new_fd != fd.number) {
628 dup2(new_fd, fd.number);
631 lseek(fd.number, fd.current_position, SEEK_SET);
635 void restore_snapshot(mc_snapshot_t snapshot)
637 XBT_DEBUG("Restore snapshot %i", snapshot->num_state);
638 const bool use_soft_dirty = _sg_mc_sparse_checkpoint && _sg_mc_soft_dirty;
639 restore_snapshot_regions(snapshot);
640 if (_sg_mc_snapshot_fds)
641 restore_snapshot_fds(snapshot);
643 mc_model_checker->process().reset_soft_dirty();
644 snapshot_ignore_restore(snapshot);
645 mc_model_checker->process().cache_flags = 0;
647 mc_model_checker->parent_snapshot_ = snapshot;