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[simgrid.git] / src / mc / remote / RemoteClient.cpp
1 /* Copyright (c) 2014-2019. The SimGrid Team. All rights reserved.          */
2
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. */
5
6 #define _FILE_OFFSET_BITS 64 /* needed for pread_whole to work as expected on 32bits */
7
8 #include "src/mc/remote/RemoteClient.hpp"
9
10 #include "src/mc/mc_smx.hpp"
11 #include "src/mc/sosp/Snapshot.hpp"
12 #include "xbt/file.hpp"
13 #include "xbt/log.h"
14
15 #include <fcntl.h>
16 #include <libunwind-ptrace.h>
17 #include <sys/mman.h> // PROT_*
18
19 using simgrid::mc::remote;
20
21 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_process, mc, "MC process information");
22
23 namespace simgrid {
24 namespace mc {
25
26 // ***** Helper stuff
27
28 // List of library which memory segments are not considered:
29 static const std::vector<std::string> filtered_libraries = {
30 #ifdef __linux__
31     "ld",
32 #elif defined __FreeBSD__
33     "ld-elf",
34     "ld-elf32",
35     "libkvm",      /* kernel data access library */
36     "libprocstat", /* process and file information retrieval */
37     "libthr",      /* thread library */
38     "libutil",
39 #endif
40     "libargp", /* workarounds for glibc-less systems */
41     "libasan", /* gcc sanitizers */
42     "libboost_chrono",
43     "libboost_context",
44     "libboost_context-mt",
45     "libboost_stacktrace_addr2line",
46     "libboost_stacktrace_backtrace",
47     "libboost_system",
48     "libboost_thread",
49     "libboost_timer",
50     "libbz2",
51     "libc",
52     "libc++",
53     "libcdt",
54     "libcgraph",
55     "libcrypto",
56     "libcxxrt",
57     "libdl",
58     "libdw",
59     "libelf",
60     "libevent",
61     "libexecinfo",
62     "libflang",
63     "libflangrti",
64     "libgcc_s",
65     "libgfortran",
66     "libimf",
67     "libintlc",
68     "libirng",
69     "liblua5.1",
70     "liblua5.3",
71     "liblzma",
72     "libm",
73     "libomp",
74     "libpapi",
75     "libpfm",
76     "libpgmath",
77     "libpthread",
78     "libquadmath",
79     "librt",
80     "libstdc++",
81     "libsvml",
82     "libtsan",  /* gcc sanitizers */
83     "libubsan", /* gcc sanitizers */
84     "libunwind",
85     "libunwind-ptrace",
86     "libunwind-x86",
87     "libunwind-x86_64",
88     "libz"};
89
90 static bool is_simgrid_lib(const std::string& libname)
91 {
92   return libname == "libsimgrid";
93 }
94
95 static bool is_filtered_lib(const std::string& libname)
96 {
97   return std::find(begin(filtered_libraries), end(filtered_libraries), libname) != end(filtered_libraries);
98 }
99
100 static std::string get_lib_name(const std::string& pathname)
101 {
102   std::string map_basename = simgrid::xbt::Path(pathname).get_base_name();
103   std::string libname;
104
105   size_t pos = map_basename.rfind(".so");
106   if (pos != std::string::npos) {
107     // strip the extension (matching regex "\.so.*$")
108     libname.assign(map_basename, 0, pos);
109
110     // strip the version suffix (matching regex "-[.0-9-]*$")
111     while (true) {
112       pos = libname.rfind('-');
113       if (pos == std::string::npos || libname.find_first_not_of(".0123456789", pos + 1) != std::string::npos)
114         break;
115       libname.erase(pos);
116     }
117   }
118
119   return libname;
120 }
121
122 static ssize_t pread_whole(int fd, void* buf, size_t count, off_t offset)
123 {
124   char* buffer       = (char*)buf;
125   ssize_t real_count = count;
126   while (count) {
127     ssize_t res = pread(fd, buffer, count, offset);
128     if (res > 0) {
129       count -= res;
130       buffer += res;
131       offset += res;
132     } else if (res == 0)
133       return -1;
134     else if (errno != EINTR) {
135       perror("pread_whole");
136       return -1;
137     }
138   }
139   return real_count;
140 }
141
142 static ssize_t pwrite_whole(int fd, const void* buf, size_t count, off_t offset)
143 {
144   const char* buffer = (const char*)buf;
145   ssize_t real_count = count;
146   while (count) {
147     ssize_t res = pwrite(fd, buffer, count, offset);
148     if (res > 0) {
149       count -= res;
150       buffer += res;
151       offset += res;
152     } else if (res == 0)
153       return -1;
154     else if (errno != EINTR)
155       return -1;
156   }
157   return real_count;
158 }
159
160 static pthread_once_t zero_buffer_flag = PTHREAD_ONCE_INIT;
161 static const void* zero_buffer;
162 static const size_t zero_buffer_size = 10 * 4096;
163
164 static void zero_buffer_init()
165 {
166   int fd = open("/dev/zero", O_RDONLY);
167   if (fd < 0)
168     xbt_die("Could not open /dev/zero");
169   zero_buffer = mmap(nullptr, zero_buffer_size, PROT_READ, MAP_SHARED, fd, 0);
170   if (zero_buffer == MAP_FAILED)
171     xbt_die("Could not map the zero buffer");
172   close(fd);
173 }
174
175 int open_vm(pid_t pid, int flags)
176 {
177   const size_t buffer_size = 30;
178   char buffer[buffer_size];
179   int res = snprintf(buffer, buffer_size, "/proc/%lli/mem", (long long)pid);
180   if (res < 0 || (size_t)res >= buffer_size) {
181     errno = ENAMETOOLONG;
182     return -1;
183   }
184   return open(buffer, flags);
185 }
186
187 // ***** Process
188
189 RemoteClient::RemoteClient(pid_t pid, int sockfd) : AddressSpace(this), pid_(pid), channel_(sockfd), running_(true)
190 {
191 }
192
193 void RemoteClient::init()
194 {
195   this->memory_map_ = simgrid::xbt::get_memory_map(this->pid_);
196   this->init_memory_map_info();
197
198   int fd = open_vm(this->pid_, O_RDWR);
199   if (fd < 0)
200     xbt_die("Could not open file for process virtual address space");
201   this->memory_file = fd;
202
203   // Read std_heap (is a struct mdesc*):
204   const simgrid::mc::Variable* std_heap_var = this->find_variable("__mmalloc_default_mdp");
205   if (not std_heap_var)
206     xbt_die("No heap information in the target process");
207   if (not std_heap_var->address)
208     xbt_die("No constant address for this variable");
209   this->read_bytes(&this->heap_address, sizeof(mdesc*), remote(std_heap_var->address));
210
211   this->smx_actors_infos.clear();
212   this->smx_dead_actors_infos.clear();
213   this->unw_addr_space            = simgrid::mc::UnwindContext::createUnwindAddressSpace();
214   this->unw_underlying_addr_space = simgrid::unw::create_addr_space();
215   this->unw_underlying_context    = simgrid::unw::create_context(this->unw_underlying_addr_space, this->pid_);
216 }
217
218 RemoteClient::~RemoteClient()
219 {
220   if (this->memory_file >= 0)
221     close(this->memory_file);
222
223   if (this->unw_underlying_addr_space != unw_local_addr_space) {
224     if (this->unw_underlying_addr_space)
225       unw_destroy_addr_space(this->unw_underlying_addr_space);
226     if (this->unw_underlying_context)
227       _UPT_destroy(this->unw_underlying_context);
228   }
229
230   unw_destroy_addr_space(this->unw_addr_space);
231 }
232
233 /** Refresh the information about the process
234  *
235  *  Do not use directly, this is used by the getters when appropriate
236  *  in order to have fresh data.
237  */
238 void RemoteClient::refresh_heap()
239 {
240   // Read/dereference/refresh the std_heap pointer:
241   if (not this->heap)
242     this->heap.reset(new s_xbt_mheap_t());
243   this->read_bytes(this->heap.get(), sizeof(mdesc), remote(this->heap_address));
244   this->cache_flags_ |= RemoteClient::cache_heap;
245 }
246
247 /** Refresh the information about the process
248  *
249  *  Do not use direclty, this is used by the getters when appropriate
250  *  in order to have fresh data.
251  * */
252 void RemoteClient::refresh_malloc_info()
253 {
254   // Refresh process->heapinfo:
255   if (this->cache_flags_ & RemoteClient::cache_malloc)
256     return;
257   size_t count = this->heap->heaplimit + 1;
258   if (this->heap_info.size() < count)
259     this->heap_info.resize(count);
260   this->read_bytes(this->heap_info.data(), count * sizeof(malloc_info), remote(this->heap->heapinfo));
261   this->cache_flags_ |= RemoteClient::cache_malloc;
262 }
263
264 /** @brief Finds the range of the different memory segments and binary paths */
265 void RemoteClient::init_memory_map_info()
266 {
267   XBT_DEBUG("Get debug information ...");
268   this->maestro_stack_start_ = nullptr;
269   this->maestro_stack_end_   = nullptr;
270   this->object_infos.resize(0);
271   this->binary_info     = nullptr;
272   this->libsimgrid_info = nullptr;
273
274   std::vector<simgrid::xbt::VmMap> const& maps = this->memory_map_;
275
276   const char* current_name = nullptr;
277
278   this->object_infos.clear();
279
280   for (size_t i = 0; i < maps.size(); i++) {
281     simgrid::xbt::VmMap const& reg = maps[i];
282     const char* pathname           = maps[i].pathname.c_str();
283
284     // Nothing to do
285     if (maps[i].pathname.empty()) {
286       current_name = nullptr;
287       continue;
288     }
289
290     // [stack], [vvar], [vsyscall], [vdso] ...
291     if (pathname[0] == '[') {
292       if ((reg.prot & PROT_WRITE) && not memcmp(pathname, "[stack]", 7)) {
293         this->maestro_stack_start_ = remote(reg.start_addr);
294         this->maestro_stack_end_   = remote(reg.end_addr);
295       }
296       current_name = nullptr;
297       continue;
298     }
299
300     if (current_name && strcmp(current_name, pathname) == 0)
301       continue;
302
303     current_name = pathname;
304     if (not(reg.prot & PROT_READ) && (reg.prot & PROT_EXEC))
305       continue;
306
307     const bool is_executable = not i;
308     std::string libname;
309     if (not is_executable) {
310       libname = get_lib_name(pathname);
311       if (is_filtered_lib(libname)) {
312         continue;
313       }
314     }
315
316     std::shared_ptr<simgrid::mc::ObjectInformation> info =
317         simgrid::mc::createObjectInformation(this->memory_map_, pathname);
318     this->object_infos.push_back(info);
319     if (is_executable)
320       this->binary_info = info;
321     else if (is_simgrid_lib(libname))
322       this->libsimgrid_info = info;
323   }
324
325   // Resolve time (including across different objects):
326   for (auto const& object_info : this->object_infos)
327     postProcessObjectInformation(this, object_info.get());
328
329   xbt_assert(this->maestro_stack_start_, "Did not find maestro_stack_start");
330   xbt_assert(this->maestro_stack_end_, "Did not find maestro_stack_end");
331
332   XBT_DEBUG("Get debug information done !");
333 }
334
335 std::shared_ptr<simgrid::mc::ObjectInformation> RemoteClient::find_object_info(RemotePtr<void> addr) const
336 {
337   for (auto const& object_info : this->object_infos)
338     if (addr.address() >= (std::uint64_t)object_info->start && addr.address() <= (std::uint64_t)object_info->end)
339       return object_info;
340   return nullptr;
341 }
342
343 std::shared_ptr<ObjectInformation> RemoteClient::find_object_info_exec(RemotePtr<void> addr) const
344 {
345   for (std::shared_ptr<ObjectInformation> const& info : this->object_infos)
346     if (addr.address() >= (std::uint64_t)info->start_exec && addr.address() <= (std::uint64_t)info->end_exec)
347       return info;
348   return nullptr;
349 }
350
351 std::shared_ptr<ObjectInformation> RemoteClient::find_object_info_rw(RemotePtr<void> addr) const
352 {
353   for (std::shared_ptr<ObjectInformation> const& info : this->object_infos)
354     if (addr.address() >= (std::uint64_t)info->start_rw && addr.address() <= (std::uint64_t)info->end_rw)
355       return info;
356   return nullptr;
357 }
358
359 simgrid::mc::Frame* RemoteClient::find_function(RemotePtr<void> ip) const
360 {
361   std::shared_ptr<simgrid::mc::ObjectInformation> info = this->find_object_info_exec(ip);
362   return info ? info->find_function((void*)ip.address()) : nullptr;
363 }
364
365 /** Find (one occurrence of) the named variable definition
366  */
367 const simgrid::mc::Variable* RemoteClient::find_variable(const char* name) const
368 {
369   // First lookup the variable in the executable shared object.
370   // A global variable used directly by the executable code from a library
371   // is reinstanciated in the executable memory .data/.bss.
372   // We need to look up the variable in the executable first.
373   if (this->binary_info) {
374     std::shared_ptr<simgrid::mc::ObjectInformation> const& info = this->binary_info;
375     const simgrid::mc::Variable* var                            = info->find_variable(name);
376     if (var)
377       return var;
378   }
379
380   for (std::shared_ptr<simgrid::mc::ObjectInformation> const& info : this->object_infos) {
381     const simgrid::mc::Variable* var = info->find_variable(name);
382     if (var)
383       return var;
384   }
385
386   return nullptr;
387 }
388
389 void RemoteClient::read_variable(const char* name, void* target, size_t size) const
390 {
391   const simgrid::mc::Variable* var = this->find_variable(name);
392   xbt_assert(var->address, "No simple location for this variable");
393   xbt_assert(var->type->full_type, "Partial type for %s, cannot check size", name);
394   xbt_assert((size_t)var->type->full_type->byte_size == size, "Unexpected size for %s (expected %zu, was %zu)", name,
395              size, (size_t)var->type->full_type->byte_size);
396   this->read_bytes(target, size, remote(var->address));
397 }
398
399 std::string RemoteClient::read_string(RemotePtr<char> address) const
400 {
401   if (not address)
402     return {};
403
404   std::vector<char> res(128);
405   off_t off = 0;
406
407   while (1) {
408     ssize_t c = pread(this->memory_file, res.data() + off, res.size() - off, (off_t)address.address() + off);
409     if (c == -1) {
410       if (errno == EINTR)
411         continue;
412       else
413         xbt_die("Could not read from from remote process");
414     }
415     if (c == 0)
416       xbt_die("Could not read string from remote process");
417
418     void* p = memchr(res.data() + off, '\0', c);
419     if (p)
420       return std::string(res.data());
421
422     off += c;
423     if (off == (off_t)res.size())
424       res.resize(res.size() * 2);
425   }
426 }
427
428 const void* RemoteClient::read_bytes(void* buffer, std::size_t size, RemotePtr<void> address,
429                                      ReadOptions /*options*/) const
430 {
431   if (pread_whole(this->memory_file, buffer, size, (size_t)address.address()) < 0)
432     xbt_die("Read at %p from process %lli failed", (void*)address.address(), (long long)this->pid_);
433   return buffer;
434 }
435
436 /** Write data to a process memory
437  *
438  *  @param buffer   local memory address (source)
439  *  @param len      data size
440  *  @param address  target process memory address (target)
441  */
442 void RemoteClient::write_bytes(const void* buffer, size_t len, RemotePtr<void> address)
443 {
444   if (pwrite_whole(this->memory_file, buffer, len, (size_t)address.address()) < 0)
445     xbt_die("Write to process %lli failed", (long long)this->pid_);
446 }
447
448 void RemoteClient::clear_bytes(RemotePtr<void> address, size_t len)
449 {
450   pthread_once(&zero_buffer_flag, zero_buffer_init);
451   while (len) {
452     size_t s = len > zero_buffer_size ? zero_buffer_size : len;
453     this->write_bytes(zero_buffer, s, address);
454     address = remote((char*)address.address() + s);
455     len -= s;
456   }
457 }
458
459 void RemoteClient::ignore_region(std::uint64_t addr, std::size_t size)
460 {
461   IgnoredRegion region;
462   region.addr = addr;
463   region.size = size;
464
465   if (ignored_regions_.empty()) {
466     ignored_regions_.push_back(region);
467     return;
468   }
469
470   unsigned int cursor           = 0;
471   IgnoredRegion* current_region = nullptr;
472
473   int start = 0;
474   int end   = ignored_regions_.size() - 1;
475   while (start <= end) {
476     cursor         = (start + end) / 2;
477     current_region = &ignored_regions_[cursor];
478     if (current_region->addr == addr) {
479       if (current_region->size == size)
480         return;
481       else if (current_region->size < size)
482         start = cursor + 1;
483       else
484         end = cursor - 1;
485     } else if (current_region->addr < addr)
486       start = cursor + 1;
487     else
488       end = cursor - 1;
489   }
490
491   std::size_t position;
492   if (current_region->addr == addr) {
493     if (current_region->size < size)
494       position = cursor + 1;
495     else
496       position = cursor;
497   } else if (current_region->addr < addr)
498     position = cursor + 1;
499   else
500     position = cursor;
501   ignored_regions_.insert(ignored_regions_.begin() + position, region);
502 }
503
504 void RemoteClient::ignore_heap(IgnoredHeapRegion const& region)
505 {
506   if (ignored_heap_.empty()) {
507     ignored_heap_.push_back(std::move(region));
508     return;
509   }
510
511   typedef std::vector<IgnoredHeapRegion>::size_type size_type;
512
513   size_type start = 0;
514   size_type end   = ignored_heap_.size() - 1;
515
516   // Binary search the position of insertion:
517   size_type cursor;
518   while (start <= end) {
519     cursor               = start + (end - start) / 2;
520     auto& current_region = ignored_heap_[cursor];
521     if (current_region.address == region.address)
522       return;
523     else if (current_region.address < region.address)
524       start = cursor + 1;
525     else if (cursor != 0)
526       end = cursor - 1;
527     // Avoid underflow:
528     else
529       break;
530   }
531
532   // Insert it mc_heap_ignore_region_t:
533   if (ignored_heap_[cursor].address < region.address)
534     ++cursor;
535   ignored_heap_.insert(ignored_heap_.begin() + cursor, region);
536 }
537
538 void RemoteClient::unignore_heap(void* address, size_t size)
539 {
540   typedef std::vector<IgnoredHeapRegion>::size_type size_type;
541
542   size_type start = 0;
543   size_type end   = ignored_heap_.size() - 1;
544
545   // Binary search:
546   size_type cursor;
547   while (start <= end) {
548     cursor       = (start + end) / 2;
549     auto& region = ignored_heap_[cursor];
550     if (region.address < address)
551       start = cursor + 1;
552     else if ((char*)region.address <= ((char*)address + size)) {
553       ignored_heap_.erase(ignored_heap_.begin() + cursor);
554       return;
555     } else if (cursor != 0)
556       end = cursor - 1;
557     // Avoid underflow:
558     else
559       break;
560   }
561 }
562
563 void RemoteClient::ignore_local_variable(const char* var_name, const char* frame_name)
564 {
565   if (frame_name != nullptr && strcmp(frame_name, "*") == 0)
566     frame_name = nullptr;
567   for (std::shared_ptr<simgrid::mc::ObjectInformation> const& info : this->object_infos)
568     info->remove_local_variable(var_name, frame_name);
569 }
570
571 std::vector<simgrid::mc::ActorInformation>& RemoteClient::actors()
572 {
573   this->refresh_simix();
574   return smx_actors_infos;
575 }
576
577 std::vector<simgrid::mc::ActorInformation>& RemoteClient::dead_actors()
578 {
579   this->refresh_simix();
580   return smx_dead_actors_infos;
581 }
582
583 void RemoteClient::dump_stack()
584 {
585   unw_addr_space_t as = unw_create_addr_space(&_UPT_accessors, BYTE_ORDER);
586   if (as == nullptr) {
587     XBT_ERROR("Could not initialize ptrace address space");
588     return;
589   }
590
591   void* context = _UPT_create(this->pid_);
592   if (context == nullptr) {
593     unw_destroy_addr_space(as);
594     XBT_ERROR("Could not initialize ptrace context");
595     return;
596   }
597
598   unw_cursor_t cursor;
599   if (unw_init_remote(&cursor, as, context) != 0) {
600     _UPT_destroy(context);
601     unw_destroy_addr_space(as);
602     XBT_ERROR("Could not initialiez ptrace cursor");
603     return;
604   }
605
606   simgrid::mc::dumpStack(stderr, std::move(cursor));
607
608   _UPT_destroy(context);
609   unw_destroy_addr_space(as);
610 }
611
612 bool RemoteClient::actor_is_enabled(aid_t pid)
613 {
614   s_mc_message_actor_enabled_t msg{MC_MESSAGE_ACTOR_ENABLED, pid};
615   process()->get_channel().send(msg);
616   char buff[MC_MESSAGE_LENGTH];
617   ssize_t received = process()->get_channel().receive(buff, MC_MESSAGE_LENGTH, true);
618   xbt_assert(received == sizeof(s_mc_message_int_t), "Unexpected size in answer to ACTOR_ENABLED");
619   return ((s_mc_message_int_t*)buff)->value;
620 }
621 }
622 }