1 /* Copyright (c) 2008-2014. 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. */
13 #include "internal_config.h"
14 #include "mc_memory_map.h"
15 #include "mc_private.h"
16 #include "xbt/module.h"
17 #include <xbt/mmalloc.h>
18 #include "../smpi/private.h"
21 #include "xbt/mmalloc/mmprivate.h"
23 #include "../simix/smx_private.h"
25 #include <libunwind.h>
28 #include "mc_private.h"
31 #include "mc_snapshot.h"
32 #include "mc_object_info.h"
35 #include "mc_protocol.h"
38 using simgrid::mc::remote;
42 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_checkpoint, mc,
43 "Logging specific to mc_checkpoint");
45 /************************************ Free functions **************************************/
46 /*****************************************************************************************/
48 s_mc_snapshot_stack::~s_mc_snapshot_stack()
50 xbt_dynar_free(&(this->stack_frames));
51 mc_unw_destroy_context(this->context);
52 xbt_free(this->context);
55 static void MC_snapshot_stack_free_voidp(void *s)
57 mc_snapshot_stack_t stack = (mc_snapshot_stack_t) * (void **) s;
61 static void local_variable_free_voidp(void *v)
63 local_variable_t var = *(local_variable_t*)v;
71 /** @brief Restore a region from a snapshot
73 * @param reg Target region
75 static void MC_region_restore(mc_mem_region_t region)
77 switch(region->storage_type()) {
78 case simgrid::mc::StorageType::NoData:
80 xbt_die("Storage type not supported");
83 case simgrid::mc::StorageType::Flat:
84 mc_model_checker->process().write_bytes(region->flat_data().data(),
85 region->size(), region->permanent_address());
88 case simgrid::mc::StorageType::Chunked:
89 mc_region_restore_sparse(&mc_model_checker->process(), region);
92 case simgrid::mc::StorageType::Privatized:
93 for (auto& p : region->privatized_data())
94 MC_region_restore(&p);
104 simgrid::mc::RegionSnapshot privatized_region(
105 RegionType region_type, void *start_addr, void* permanent_addr, size_t size
108 size_t process_count = MC_smpi_process_count();
110 // Read smpi_privatisation_regions from MCed:
111 smpi_privatisation_region_t remote_smpi_privatisation_regions;
112 mc_model_checker->process().read_variable(
113 "smpi_privatisation_regions",
114 &remote_smpi_privatisation_regions, sizeof(remote_smpi_privatisation_regions));
115 s_smpi_privatisation_region_t privatisation_regions[process_count];
116 mc_model_checker->process().read_bytes(
117 &privatisation_regions, sizeof(privatisation_regions),
118 remote(remote_smpi_privatisation_regions));
120 std::vector<simgrid::mc::RegionSnapshot> data;
121 data.reserve(process_count);
122 for (size_t i = 0; i < process_count; i++)
124 simgrid::mc::region(region_type, start_addr,
125 privatisation_regions[i].address, size)
128 simgrid::mc::RegionSnapshot region = simgrid::mc::RegionSnapshot(
129 region_type, start_addr, permanent_addr, size);
130 region.privatized_data(std::move(data));
131 return std::move(region);
139 static void MC_snapshot_add_region(int index, mc_snapshot_t snapshot,
140 simgrid::mc::RegionType type,
141 mc_object_info_t object_info,
142 void *start_addr, void* permanent_addr, size_t size)
144 if (type == simgrid::mc::RegionType::Data)
145 xbt_assert(object_info, "Missing object info for object.");
146 else if (type == simgrid::mc::RegionType::Heap)
147 xbt_assert(!object_info, "Unexpected object info for heap region.");
149 const bool privatization_aware = MC_object_info_is_privatized(object_info);
151 simgrid::mc::RegionSnapshot region;
152 if (privatization_aware && MC_smpi_process_count())
153 region = simgrid::mc::privatized_region(type, start_addr, permanent_addr, size);
155 region = simgrid::mc::region(type, start_addr, permanent_addr, size);
157 region.object_info(object_info);
158 snapshot->snapshot_regions[index]
159 = std::unique_ptr<simgrid::mc::RegionSnapshot>(
160 new simgrid::mc::RegionSnapshot(std::move(region)));
164 static void MC_get_memory_regions(mc_process_t process, mc_snapshot_t snapshot)
166 const size_t n = process->object_infos_size;
167 snapshot->snapshot_regions.resize(n + 1);
168 for (size_t i = 0; i != n; ++i) {
169 mc_object_info_t object_info = process->object_infos[i];
170 MC_snapshot_add_region(i, snapshot, simgrid::mc::RegionType::Data, object_info,
171 object_info->start_rw, object_info->start_rw,
172 object_info->end_rw - object_info->start_rw);
175 xbt_mheap_t heap = process->get_heap();
176 void *start_heap = heap->base;
177 void *end_heap = heap->breakval;
179 MC_snapshot_add_region(n, snapshot, simgrid::mc::RegionType::Heap, NULL,
180 start_heap, start_heap,
181 (char *) end_heap - (char *) start_heap);
182 snapshot->heap_bytes_used = mmalloc_get_bytes_used_remote(
184 process->get_malloc_info());
187 if (smpi_privatize_global_variables && MC_smpi_process_count()) {
188 // snapshot->privatization_index = smpi_loaded_page
189 mc_model_checker->process().read_variable(
190 "smpi_loaded_page", &snapshot->privatization_index,
191 sizeof(snapshot->privatization_index));
195 snapshot->privatization_index = simgrid::mc::ProcessIndexMissing;
199 /** \brief Fills the position of the segments (executable, read-only, read/write).
201 * `dl_iterate_phdr` would be more robust but would not work in cross-process.
203 void MC_find_object_address(std::vector<simgrid::mc::VmMap> const& maps, mc_object_info_t result)
205 const char *name = basename(result->file_name);
206 for (size_t i = 0; i < maps.size(); ++i) {
207 simgrid::mc::VmMap const& reg = maps[i];
208 if (maps[i].pathname.empty()
209 || strcmp(basename(maps[i].pathname.c_str()), name)) {
211 } else if ((reg.prot & PROT_WRITE)) {
212 xbt_assert(!result->start_rw,
213 "Multiple read-write segments for %s, not supported",
214 maps[i].pathname.c_str());
215 result->start_rw = (char*) reg.start_addr;
216 result->end_rw = (char*) reg.end_addr;
217 // .bss is usually after the .data:
218 simgrid::mc::VmMap const& next = maps[i + 1];
219 if (next.pathname.empty() && (next.prot & PROT_WRITE)
220 && next.start_addr == reg.end_addr) {
221 result->end_rw = (char*) maps[i + 1].end_addr;
223 } else if ((reg.prot & PROT_READ) && (reg.prot & PROT_EXEC)) {
224 xbt_assert(!result->start_exec,
225 "Multiple executable segments for %s, not supported",
226 maps[i].pathname.c_str());
227 result->start_exec = (char*) reg.start_addr;
228 result->end_exec = (char*) reg.end_addr;
229 } else if ((reg.prot & PROT_READ) && !(reg.prot & PROT_EXEC)) {
230 xbt_assert(!result->start_ro,
231 "Multiple read only segments for %s, not supported",
232 maps[i].pathname.c_str());
233 result->start_ro = (char*) reg.start_addr;
234 result->end_ro = (char*) reg.end_addr;
238 result->start = result->start_rw;
239 if ((const void*) result->start_ro > result->start)
240 result->start = result->start_ro;
241 if ((const void*) result->start_exec > result->start)
242 result->start = result->start_exec;
244 result->end = result->end_rw;
245 if (result->end_ro && (const void*) result->end_ro < result->end)
246 result->end = result->end_ro;
247 if (result->end_exec && (const void*) result->end_exec > result->end)
248 result->end = result->end_exec;
250 xbt_assert(result->file_name);
251 xbt_assert(result->start_rw);
252 xbt_assert(result->start_exec);
255 /************************************* Take Snapshot ************************************/
256 /****************************************************************************************/
258 /** \brief Checks whether the variable is in scope for a given IP.
260 * A variable may be defined only from a given value of IP.
262 * \param var Variable description
263 * \param frame Scope description
264 * \param ip Instruction pointer
265 * \return true if the variable is valid
267 static bool mc_valid_variable(dw_variable_t var, dw_frame_t scope,
270 // The variable is not yet valid:
271 if ((const void *) ((const char *) scope->low_pc + var->start_scope) > ip)
277 static void mc_fill_local_variables_values(mc_stack_frame_t stack_frame,
278 dw_frame_t scope, int process_index,
279 std::vector<s_local_variable>& result)
281 mc_process_t process = &mc_model_checker->process();
283 void *ip = (void *) stack_frame->ip;
284 if (ip < scope->low_pc || ip >= scope->high_pc)
288 dw_variable_t current_variable;
289 xbt_dynar_foreach(scope->variables, cursor, current_variable) {
291 if (!mc_valid_variable(current_variable, scope, (void *) stack_frame->ip))
295 // FIXME, get rid of `region_type`
296 if ((long) stack_frame->ip > (long) process->libsimgrid_info->start_exec)
301 s_local_variable_t new_var;
302 new_var.subprogram = stack_frame->frame;
303 new_var.ip = stack_frame->ip;
304 new_var.name = current_variable->name;
305 new_var.type = current_variable->type;
306 new_var.region = region_type;
307 new_var.address = nullptr;
309 if (current_variable->address != NULL) {
310 new_var.address = current_variable->address;
311 } else if (current_variable->locations.size != 0) {
312 s_mc_location_t location;
313 mc_dwarf_resolve_locations(
314 &location, ¤t_variable->locations,
315 current_variable->object_info,
316 &(stack_frame->unw_cursor),
317 (void *) stack_frame->frame_base,
318 &mc_model_checker->process(), process_index);
320 switch(mc_get_location_type(&location)) {
321 case MC_LOCATION_TYPE_ADDRESS:
322 new_var.address = location.memory_location;
324 case MC_LOCATION_TYPE_REGISTER:
326 xbt_die("Cannot handle non-address variable");
330 xbt_die("No address");
333 result.push_back(std::move(new_var));
336 // Recursive processing of nested scopes:
337 dw_frame_t nested_scope = NULL;
338 xbt_dynar_foreach(scope->scopes, cursor, nested_scope) {
339 mc_fill_local_variables_values(stack_frame, nested_scope, process_index, result);
343 static std::vector<s_local_variable> MC_get_local_variables_values(xbt_dynar_t stack_frames, int process_index)
346 unsigned cursor1 = 0;
347 mc_stack_frame_t stack_frame;
349 std::vector<s_local_variable> variables;
350 xbt_dynar_foreach(stack_frames, cursor1, stack_frame) {
351 mc_fill_local_variables_values(stack_frame, stack_frame->frame, process_index, variables);
353 return std::move(variables);
356 static void MC_stack_frame_free_voipd(void *s)
358 mc_stack_frame_t stack_frame = *(mc_stack_frame_t *) s;
362 static xbt_dynar_t MC_unwind_stack_frames(mc_unw_context_t stack_context)
364 mc_process_t process = &mc_model_checker->process();
366 xbt_dynar_new(sizeof(mc_stack_frame_t), MC_stack_frame_free_voipd);
370 // TODO, check condition check (unw_init_local==0 means end of frame)
371 if (mc_unw_init_cursor(&c, stack_context) != 0) {
373 xbt_die("Could not initialize stack unwinding");
378 mc_stack_frame_t stack_frame = new s_mc_stack_frame_t();
379 xbt_dynar_push(result, &stack_frame);
381 stack_frame->unw_cursor = c;
385 unw_get_reg(&c, UNW_REG_IP, &ip);
386 unw_get_reg(&c, UNW_REG_SP, &sp);
388 stack_frame->ip = ip;
389 stack_frame->sp = sp;
391 // TODO, use real addresses in frame_t instead of fixing it here
393 dw_frame_t frame = process->find_function(remote(ip));
394 stack_frame->frame = frame;
397 stack_frame->frame_name = frame->name;
398 stack_frame->frame_base =
399 (unw_word_t) mc_find_frame_base(frame, frame->object_info, &c);
401 stack_frame->frame_base = 0;
402 stack_frame->frame_name = std::string();
405 /* Stop before context switch with maestro */
406 if (frame != NULL && frame->name != NULL
407 && !strcmp(frame->name, "smx_ctx_sysv_wrapper"))
410 int ret = unw_step(&c);
412 xbt_die("Unexpected end of stack.");
413 } else if (ret < 0) {
414 xbt_die("Error while unwinding stack");
418 if (xbt_dynar_length(result) == 0) {
419 XBT_INFO("unw_init_local failed");
426 static xbt_dynar_t MC_take_snapshot_stacks(mc_snapshot_t * snapshot)
430 xbt_dynar_new(sizeof(s_mc_snapshot_stack_t),
431 MC_snapshot_stack_free_voidp);
433 unsigned int cursor = 0;
434 stack_region_t current_stack;
436 // FIXME, cross-process support (stack_areas)
437 xbt_dynar_foreach(stacks_areas, cursor, current_stack) {
438 mc_snapshot_stack_t st = new s_mc_snapshot_stack();
440 // Read the context from remote process:
441 unw_context_t context;
442 mc_model_checker->process().read_bytes(
443 &context, sizeof(context), remote(current_stack->context));
445 st->context = xbt_new0(s_mc_unw_context_t, 1);
446 if (mc_unw_init_context(st->context, &mc_model_checker->process(),
448 xbt_die("Could not initialise the libunwind context.");
451 st->stack_frames = MC_unwind_stack_frames(st->context);
452 st->local_variables = MC_get_local_variables_values(st->stack_frames, current_stack->process_index);
453 st->process_index = current_stack->process_index;
455 unw_word_t sp = xbt_dynar_get_as(st->stack_frames, 0, mc_stack_frame_t)->sp;
457 xbt_dynar_push(res, &st);
459 (char*) current_stack->address + current_stack->size - (char*) sp;
460 (*snapshot)->stack_sizes.push_back(stack_size);
467 static std::vector<s_mc_heap_ignore_region_t> MC_take_snapshot_ignore()
469 std::vector<s_mc_heap_ignore_region_t> res;
471 if (mc_heap_comparison_ignore == NULL)
472 return std::move(res);
474 unsigned int cursor = 0;
475 mc_heap_ignore_region_t current_region;
477 xbt_dynar_foreach(mc_heap_comparison_ignore, cursor, current_region) {
478 s_mc_heap_ignore_region_t new_region;
479 new_region.address = current_region->address;
480 new_region.size = current_region->size;
481 new_region.block = current_region->block;
482 new_region.fragment = current_region->fragment;
483 res.push_back(std::move(new_region));
486 return std::move(res);
489 static void MC_snapshot_handle_ignore(mc_snapshot_t snapshot)
491 xbt_assert(snapshot->process);
494 for (auto const& region : mc_model_checker->process().ignored_regions()) {
495 s_mc_snapshot_ignored_data_t ignored_data;
496 ignored_data.start = (void*)region.addr;
497 ignored_data.data.resize(region.size);
498 // TODO, we should do this once per privatization segment:
499 snapshot->process->read_bytes(
500 ignored_data.data.data(), region.size, remote(region.addr),
501 simgrid::mc::ProcessIndexDisabled);
502 snapshot->ignored_data.push_back(std::move(ignored_data));
506 for(auto const& region : mc_model_checker->process().ignored_regions()) {
507 snapshot->process->clear_bytes(remote(region.addr), region.size);
512 static void MC_snapshot_ignore_restore(mc_snapshot_t snapshot)
514 for (auto const& ignored_data : snapshot->ignored_data)
515 snapshot->process->write_bytes(
516 ignored_data.data.data(), ignored_data.data.size(),
517 remote(ignored_data.start));
520 static std::vector<s_fd_infos_t> MC_get_current_fds(pid_t pid)
522 const size_t fd_dir_path_size = 20;
523 char fd_dir_path[fd_dir_path_size];
524 int res = snprintf(fd_dir_path, fd_dir_path_size,
525 "/proc/%lli/fd", (long long int) pid);
526 xbt_assert(res >= 0);
527 if ((size_t) res > fd_dir_path_size)
528 xbt_die("Unexpected buffer is too small for fd_dir_path");
530 DIR* fd_dir = opendir(fd_dir_path);
532 xbt_die("Cannot open directory '/proc/self/fd'\n");
534 std::vector<s_fd_infos_t> fds;
536 struct dirent* fd_number;
537 while ((fd_number = readdir(fd_dir))) {
539 int fd_value = atoi(fd_number->d_name);
544 const size_t source_size = 25;
546 int res = snprintf(source, source_size, "/proc/%lli/fd/%s",
547 (long long int) pid, fd_number->d_name);
548 xbt_assert(res >= 0);
549 if ((size_t) res > source_size)
550 xbt_die("Unexpected buffer is too small for fd %s", fd_number->d_name);
552 const size_t link_size = 200;
554 res = readlink(source, link, link_size);
556 xbt_die("Could not read link for %s", source);
559 xbt_die("Buffer to small for link of %s", source);
563 if(smpi_is_privatisation_file(link))
566 // This is (probably) the DIR* we are reading:
567 // TODO, read all the file entries at once and close the DIR.*
568 if(strcmp(fd_dir_path, link) == 0)
571 // We don't handle them.
572 // It does not mean we should silently ignore them however.
573 if (strncmp(link, "pipe:", 5) == 0 || strncmp(link, "socket:", 7) == 0)
576 // If dot_output enabled, do not handle the corresponding file
577 if (dot_output != NULL && strcmp(basename(link), _sg_mc_dot_output_file) == 0)
580 // This is probably a shared memory used by lttng-ust:
581 if(strncmp("/dev/shm/ust-shm-tmp-", link, 21)==0)
584 // Add an entry for this FD in the snapshot:
586 fd.filename = std::string(link);
587 fd.number = fd_value;
588 fd.flags = fcntl(fd_value, F_GETFL) | fcntl(fd_value, F_GETFD) ;
589 fd.current_position = lseek(fd_value, 0, SEEK_CUR);
590 fds.push_back(std::move(fd));
594 return std::move(fds);
597 mc_snapshot_t MC_take_snapshot(int num_state)
599 XBT_DEBUG("Taking snapshot %i", num_state);
601 mc_process_t mc_process = &mc_model_checker->process();
603 mc_snapshot_t snapshot = new simgrid::mc::Snapshot();
605 snapshot->process = mc_process;
606 snapshot->num_state = num_state;
608 smx_process_t process;
609 MC_EACH_SIMIX_PROCESS(process,
610 snapshot->enabled_processes.insert(process->pid));
612 MC_snapshot_handle_ignore(snapshot);
614 if (_sg_mc_snapshot_fds)
615 snapshot->current_fds = MC_get_current_fds(process->pid);
617 /* Save the std heap and the writable mapped pages of libsimgrid and binary */
618 MC_get_memory_regions(mc_process, snapshot);
620 snapshot->to_ignore = MC_take_snapshot_ignore();
622 if (_sg_mc_visited > 0 || strcmp(_sg_mc_property_file, "")) {
624 MC_take_snapshot_stacks(&snapshot);
625 if (_sg_mc_hash && snapshot->stacks != NULL) {
626 snapshot->hash = mc_hash_processes_state(num_state, snapshot->stacks);
634 MC_snapshot_ignore_restore(snapshot);
639 void MC_restore_snapshot_regions(mc_snapshot_t snapshot)
641 for(std::unique_ptr<s_mc_mem_region_t> const& region : snapshot->snapshot_regions) {
642 // For privatized, variables we decided it was not necessary to take the snapshot:
644 MC_region_restore(region.get());
648 // TODO, send a message to implement this in the MCed process
649 if(snapshot->privatization_index >= 0) {
650 // We just rewrote the global variables.
651 // The privatisation segment SMPI thinks
652 // is mapped might be inconsistent with the segment which
653 // is really mapped in memory (kernel state).
654 // We ask politely SMPI to map the segment anyway,
655 // even if it thinks it is the current one:
656 smpi_really_switch_data_segment(snapshot->privatization_index);
662 void MC_restore_snapshot_fds(mc_snapshot_t snapshot)
664 if (mc_mode == MC_MODE_SERVER)
665 xbt_die("FD snapshot not implemented in client/server mode.");
667 for (auto const& fd : snapshot->current_fds) {
669 int new_fd = open(fd.filename.c_str(), fd.flags);
671 xbt_die("Could not reopen the file %s fo restoring the file descriptor",
672 fd.filename.c_str());
674 if (new_fd != fd.number) {
675 dup2(new_fd, fd.number);
678 lseek(fd.number, fd.current_position, SEEK_SET);
682 void MC_restore_snapshot(mc_snapshot_t snapshot)
684 XBT_DEBUG("Restore snapshot %i", snapshot->num_state);
685 MC_restore_snapshot_regions(snapshot);
686 if (_sg_mc_snapshot_fds)
687 MC_restore_snapshot_fds(snapshot);
688 MC_snapshot_ignore_restore(snapshot);
689 mc_model_checker->process().cache_flags = 0;
692 mc_snapshot_t simcall_HANDLER_mc_snapshot(smx_simcall_t simcall)
694 return MC_take_snapshot(1);