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[simgrid.git] / src / mc / mc_process.cpp
1 /* Copyright (c) 2014-2015. The SimGrid Team.
2  * All rights reserved.                                                     */
3
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. */
6
7 #include <assert.h>
8 #include <stddef.h>
9 #include <stdbool.h>
10 #include <stdint.h>
11 #include <errno.h>
12
13 #include <sys/types.h>
14 #include <fcntl.h>
15 #include <unistd.h>
16 #include <regex.h>
17 #include <sys/mman.h> // PROT_*
18
19 #include <pthread.h>
20
21 #include <libgen.h>
22
23 #include <libunwind.h>
24 #include <libunwind-ptrace.h>
25
26 #include <xbt/mmalloc.h>
27
28 #include "mc_process.h"
29 #include "mc_object_info.h"
30 #include "AddressSpace.hpp"
31 #include "mc_unw.h"
32 #include "mc_snapshot.h"
33 #include "mc_ignore.h"
34 #include "mc_smx.h"
35 #include "mc_server.h"
36
37 using simgrid::mc::remote;
38
39 extern "C" {
40
41 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_process, mc,
42                                 "MC process information");
43
44 // ***** Helper stuff
45
46 #define SO_RE "\\.so[\\.0-9]*$"
47 #define VERSION_RE "-[\\.0-9]*$"
48
49 static const char *const FILTERED_LIBS[] = {
50   "libstdc++",
51   "libc++",
52   "libm",
53   "libgcc_s",
54   "libpthread",
55   "libunwind",
56   "libunwind-x86_64",
57   "libunwind-x86",
58   "libunwind-ptrace",
59   "libdw",
60   "libdl",
61   "librt",
62   "liblzma",
63   "libelf",
64   "libbz2",
65   "libz",
66   "libelf",
67   "libc",
68   "ld"
69 };
70
71 static bool MC_is_simgrid_lib(const char* libname)
72 {
73   return !strcmp(libname, "libsimgrid");
74 }
75
76 static bool MC_is_filtered_lib(const char* libname)
77 {
78   for (const char* filtered_lib : FILTERED_LIBS)
79     if (strcmp(libname, filtered_lib)==0)
80       return true;
81   return false;
82 }
83
84 struct s_mc_memory_map_re {
85   regex_t so_re;
86   regex_t version_re;
87 };
88
89 static char* MC_get_lib_name(const char* pathname, struct s_mc_memory_map_re* res)
90 {
91   const char* map_basename = basename((char*) pathname);
92
93   regmatch_t match;
94   if(regexec(&res->so_re, map_basename, 1, &match, 0))
95     return NULL;
96
97   char* libname = strndup(map_basename, match.rm_so);
98
99   // Strip the version suffix:
100   if(libname && !regexec(&res->version_re, libname, 1, &match, 0)) {
101     char* temp = libname;
102     libname = strndup(temp, match.rm_so);
103     free(temp);
104   }
105
106   return libname;
107 }
108
109 static ssize_t pread_whole(int fd, void *buf, size_t count, off_t offset)
110 {
111   char* buffer = (char*) buf;
112   ssize_t real_count = count;
113   while (count) {
114     ssize_t res = pread(fd, buffer, count, offset);
115     if (res > 0) {
116       count  -= res;
117       buffer += res;
118       offset += res;
119     } else if (res==0) {
120       return -1;
121     } else if (errno != EINTR) {
122       return -1;
123     }
124   }
125   return real_count;
126 }
127
128 static ssize_t pwrite_whole(int fd, const void *buf, size_t count, off_t offset)
129 {
130   const char* buffer = (const char*) buf;
131   ssize_t real_count = count;
132   while (count) {
133     ssize_t res = pwrite(fd, buffer, count, offset);
134     if (res > 0) {
135       count  -= res;
136       buffer += res;
137       offset += res;
138     } else if (res==0) {
139       return -1;
140     } else if (errno != EINTR) {
141       return -1;
142     }
143   }
144   return real_count;
145 }
146
147 static pthread_once_t zero_buffer_flag = PTHREAD_ONCE_INIT;
148 static const void* zero_buffer;
149 static const size_t zero_buffer_size = 10 * 4096;
150
151 static void MC_zero_buffer_init(void)
152 {
153   int fd = open("/dev/zero", O_RDONLY);
154   if (fd<0)
155     xbt_die("Could not open /dev/zero");
156   zero_buffer = mmap(NULL, zero_buffer_size, PROT_READ, MAP_SHARED, fd, 0);
157   if (zero_buffer == MAP_FAILED)
158     xbt_die("Could not map the zero buffer");
159   close(fd);
160 }
161
162 }
163
164 namespace simgrid {
165 namespace mc {
166
167 int open_vm(pid_t pid, int flags)
168 {
169   const size_t buffer_size = 30;
170   char buffer[buffer_size];
171   int res = snprintf(buffer, buffer_size, "/proc/%lli/mem", (long long) pid);
172   if (res < 0 || (size_t) res >= buffer_size) {
173     errno = ENAMETOOLONG;
174     return -1;
175   }
176   return open(buffer, flags);
177 }
178
179   
180 }
181 }
182
183 // ***** Process
184
185 namespace simgrid {
186 namespace mc {
187
188 Process::Process(pid_t pid, int sockfd)
189 {
190   Process* process = this;
191
192   process->process_flags = MC_PROCESS_NO_FLAG;
193   process->socket = sockfd;
194   process->pid_ = pid;
195   if (pid==getpid())
196     process->process_flags |= MC_PROCESS_SELF_FLAG;
197   process->running_ = true;
198   process->status_ = 0;
199   process->memory_map_ = get_memory_map(pid);
200   process->cache_flags = MC_PROCESS_CACHE_FLAG_NONE;
201   process->heap = NULL;
202   process->heap_info = NULL;
203   process->init_memory_map_info();
204
205   // Open the memory file
206   if (process->is_self())
207     process->memory_file = -1;
208   else {
209     int fd = open_vm(process->pid_, O_RDWR);
210     if (fd<0)
211       xbt_die("Could not open file for process virtual address space");
212     process->memory_file = fd;
213   }
214
215   // Read std_heap (is a struct mdesc*):
216   dw_variable_t std_heap_var = process->find_variable("__mmalloc_default_mdp");
217   if (!std_heap_var)
218     xbt_die("No heap information in the target process");
219   if(!std_heap_var->address)
220     xbt_die("No constant address for this variable");
221   process->read_bytes(&process->heap_address, sizeof(struct mdesc*),
222     remote(std_heap_var->address),
223     simgrid::mc::ProcessIndexDisabled);
224
225   process->smx_process_infos = MC_smx_process_info_list_new();
226   process->smx_old_process_infos = MC_smx_process_info_list_new();
227
228   process->unw_addr_space = unw_create_addr_space(&mc_unw_accessors  , __BYTE_ORDER);
229   if (process->process_flags & MC_PROCESS_SELF_FLAG) {
230     process->unw_underlying_addr_space = unw_local_addr_space;
231     process->unw_underlying_context = NULL;
232   } else {
233     process->unw_underlying_addr_space = unw_create_addr_space(&mc_unw_vmread_accessors, __BYTE_ORDER);
234     process->unw_underlying_context = _UPT_create(pid);
235   }
236 }
237
238 Process::~Process()
239 {
240   Process* process = this;
241
242   process->process_flags = MC_PROCESS_NO_FLAG;
243   process->pid_ = 0;
244
245   process->maestro_stack_start_ = nullptr;
246   process->maestro_stack_end_ = nullptr;
247
248   xbt_dynar_free(&process->smx_process_infos);
249   xbt_dynar_free(&process->smx_old_process_infos);
250
251   size_t i;
252   for (i=0; i!=process->object_infos_size; ++i) {
253     MC_free_object_info(&process->object_infos[i]);
254   }
255   free(process->object_infos);
256   process->object_infos = NULL;
257   process->object_infos_size = 0;
258   if (process->memory_file >= 0) {
259     close(process->memory_file);
260   }
261
262   if (process->unw_underlying_addr_space != unw_local_addr_space) {
263     unw_destroy_addr_space(process->unw_underlying_addr_space);
264     _UPT_destroy(process->unw_underlying_context);
265   }
266   process->unw_underlying_context = NULL;
267   process->unw_underlying_addr_space = NULL;
268
269   unw_destroy_addr_space(process->unw_addr_space);
270   process->unw_addr_space = NULL;
271
272   process->cache_flags = MC_PROCESS_CACHE_FLAG_NONE;
273
274   free(process->heap);
275   process->heap = NULL;
276
277   free(process->heap_info);
278   process->heap_info = NULL;
279 }
280
281 /** Refresh the information about the process
282  *
283  *  Do not use direclty, this is used by the getters when appropriate
284  *  in order to have fresh data.
285  */
286 void Process::refresh_heap()
287 {
288   xbt_assert(mc_mode == MC_MODE_SERVER);
289   xbt_assert(!this->is_self());
290   // Read/dereference/refresh the std_heap pointer:
291   if (!this->heap) {
292     this->heap = (struct mdesc*) malloc(sizeof(struct mdesc));
293   }
294   this->read_bytes(this->heap, sizeof(struct mdesc), remote(this->heap_address),
295     simgrid::mc::ProcessIndexDisabled);
296   this->cache_flags |= MC_PROCESS_CACHE_FLAG_HEAP;
297 }
298
299 /** Refresh the information about the process
300  *
301  *  Do not use direclty, this is used by the getters when appropriate
302  *  in order to have fresh data.
303  * */
304 void Process::refresh_malloc_info()
305 {
306   xbt_assert(mc_mode == MC_MODE_SERVER);
307   xbt_assert(!this->is_self());
308   if (!(this->cache_flags & MC_PROCESS_CACHE_FLAG_HEAP))
309     this->refresh_heap();
310   // Refresh process->heapinfo:
311   size_t malloc_info_bytesize =
312     (this->heap->heaplimit + 1) * sizeof(malloc_info);
313   this->heap_info = (malloc_info*) realloc(this->heap_info, malloc_info_bytesize);
314   this->read_bytes(this->heap_info, malloc_info_bytesize,
315     remote(this->heap->heapinfo), simgrid::mc::ProcessIndexDisabled);
316   this->cache_flags |= MC_PROCESS_CACHE_FLAG_MALLOC_INFO;
317 }
318
319 /** @brief Finds the range of the different memory segments and binary paths */
320 void Process::init_memory_map_info()
321 {
322   XBT_DEBUG("Get debug information ...");
323   this->maestro_stack_start_ = nullptr;
324   this->maestro_stack_end_ = nullptr;
325   this->object_infos = NULL;
326   this->object_infos_size = 0;
327   this->binary_info = NULL;
328   this->libsimgrid_info = NULL;
329
330   struct s_mc_memory_map_re res;
331
332   if(regcomp(&res.so_re, SO_RE, 0) || regcomp(&res.version_re, VERSION_RE, 0))
333     xbt_die(".so regexp did not compile");
334
335   std::vector<simgrid::mc::VmMap> const& maps = this->memory_map_;
336
337   const char* current_name = NULL;
338
339   for (size_t i=0; i < maps.size(); i++) {
340     simgrid::mc::VmMap const& reg = maps[i];
341     const char* pathname = maps[i].pathname.c_str();
342
343     // Nothing to do
344     if (maps[i].pathname.empty()) {
345       current_name = NULL;
346       continue;
347     }
348
349     // [stack], [vvar], [vsyscall], [vdso] ...
350     if (pathname[0] == '[') {
351       if ((reg.prot & PROT_WRITE) && !memcmp(pathname, "[stack]", 7)) {
352         this->maestro_stack_start_ = remote(reg.start_addr);
353         this->maestro_stack_end_ = remote(reg.end_addr);
354       }
355       current_name = NULL;
356       continue;
357     }
358
359     if (current_name && strcmp(current_name, pathname)==0)
360       continue;
361
362     current_name = pathname;
363     if (!(reg.prot & PROT_READ) && (reg.prot & PROT_EXEC))
364       continue;
365
366     const bool is_executable = !i;
367     char* libname = NULL;
368     if (!is_executable) {
369       libname = MC_get_lib_name(pathname, &res);
370       if(!libname)
371         continue;
372       if (MC_is_filtered_lib(libname)) {
373         free(libname);
374         continue;
375       }
376     }
377
378     mc_object_info_t info =
379       MC_find_object_info(this->memory_map_, pathname, is_executable);
380     this->object_infos = (mc_object_info_t*) realloc(this->object_infos,
381       (this->object_infos_size+1) * sizeof(mc_object_info_t*));
382     this->object_infos[this->object_infos_size] = info;
383     this->object_infos_size++;
384     if (is_executable)
385       this->binary_info = info;
386     else if (libname && MC_is_simgrid_lib(libname))
387       this->libsimgrid_info = info;
388     free(libname);
389   }
390
391   regfree(&res.so_re);
392   regfree(&res.version_re);
393
394   // Resolve time (including accross differents objects):
395   for (size_t i=0; i!=this->object_infos_size; ++i)
396     MC_post_process_object_info(this, this->object_infos[i]);
397
398   xbt_assert(this->maestro_stack_start_, "Did not find maestro_stack_start");
399   xbt_assert(this->maestro_stack_end_, "Did not find maestro_stack_end");
400
401   XBT_DEBUG("Get debug information done !");
402 }
403
404 mc_object_info_t Process::find_object_info(remote_ptr<void> addr) const
405 {
406   size_t i;
407   for (i = 0; i != this->object_infos_size; ++i) {
408     if (addr.address() >= (std::uint64_t)this->object_infos[i]->start
409         && addr.address() <= (std::uint64_t)this->object_infos[i]->end) {
410       return this->object_infos[i];
411     }
412   }
413   return NULL;
414 }
415
416 mc_object_info_t Process::find_object_info_exec(remote_ptr<void> addr) const
417 {
418   size_t i;
419   for (i = 0; i != this->object_infos_size; ++i) {
420     if (addr.address() >= (std::uint64_t)this->object_infos[i]->start_exec
421         && addr.address() <= (std::uint64_t)this->object_infos[i]->end_exec) {
422       return this->object_infos[i];
423     }
424   }
425   return NULL;
426 }
427
428 mc_object_info_t Process::find_object_info_rw(remote_ptr<void> addr) const
429 {
430   size_t i;
431   for (i = 0; i != this->object_infos_size; ++i) {
432     if (addr.address() >= (std::uint64_t)this->object_infos[i]->start_rw
433         && addr.address() <= (std::uint64_t)this->object_infos[i]->end_rw) {
434       return this->object_infos[i];
435     }
436   }
437   return NULL;
438 }
439
440 dw_frame_t Process::find_function(remote_ptr<void> ip) const
441 {
442   mc_object_info_t info = this->find_object_info_exec(ip);
443   if (info == NULL)
444     return NULL;
445   else
446     return MC_file_object_info_find_function(info, (void*) ip.address());
447 }
448
449 /** Find (one occurence of) the named variable definition
450  */
451 dw_variable_t Process::find_variable(const char* name) const
452 {
453   const size_t n = this->object_infos_size;
454   size_t i;
455
456   // First lookup the variable in the executable shared object.
457   // A global variable used directly by the executable code from a library
458   // is reinstanciated in the executable memory .data/.bss.
459   // We need to look up the variable in the execvutable first.
460   if (this->binary_info) {
461     mc_object_info_t info = this->binary_info;
462     dw_variable_t var = MC_file_object_info_find_variable_by_name(info, name);
463     if (var)
464       return var;
465   }
466
467   for (i=0; i!=n; ++i) {
468     mc_object_info_t info = this->object_infos[i];
469     dw_variable_t var = MC_file_object_info_find_variable_by_name(info, name);
470     if (var)
471       return var;
472   }
473
474   return NULL;
475 }
476
477 void Process::read_variable(const char* name, void* target, size_t size) const
478 {
479   dw_variable_t var = this->find_variable(name);
480   if (!var->address)
481     xbt_die("No simple location for this variable");
482   if (!var->type->full_type)
483     xbt_die("Partial type for %s, cannot check size", name);
484   if ((size_t) var->type->full_type->byte_size != size)
485     xbt_die("Unexpected size for %s (expected %zi, was %zi)",
486       name, size, (size_t) var->type->full_type->byte_size);
487   this->read_bytes(target, size, remote(var->address));
488 }
489
490 char* Process::read_string(remote_ptr<void> address) const
491 {
492   if (!address)
493     return NULL;
494   if (this->is_self())
495     return strdup((char*) address.address());
496
497   off_t len = 128;
498   char* res = (char*) malloc(len);
499   off_t off = 0;
500
501   while (1) {
502     ssize_t c = pread(this->memory_file, res + off, len - off, (off_t) address.address() + off);
503     if (c == -1) {
504       if (errno == EINTR)
505         continue;
506       else
507         xbt_die("Could not read from from remote process");
508     }
509     if (c==0)
510       xbt_die("Could not read string from remote process");
511
512     void* p = memchr(res + off, '\0', c);
513     if (p)
514       return res;
515
516     off += c;
517     if (off == len) {
518       len *= 2;
519       res = (char*) realloc(res, len);
520     }
521   }
522 }
523
524 const void *Process::read_bytes(void* buffer, std::size_t size,
525   remote_ptr<void> address, int process_index,
526   AddressSpace::ReadMode mode) const
527 {
528   if (process_index != simgrid::mc::ProcessIndexDisabled) {
529     mc_object_info_t info = this->find_object_info_rw((void*)address.address());
530     // Segment overlap is not handled.
531     if (MC_object_info_is_privatized(info)) {
532       if (process_index < 0)
533         xbt_die("Missing process index");
534       if (process_index >= (int) MC_smpi_process_count())
535         xbt_die("Invalid process index");
536
537       // Read smpi_privatisation_regions from MCed:
538       smpi_privatisation_region_t remote_smpi_privatisation_regions =
539         mc_model_checker->process().read_variable<smpi_privatisation_region_t>(
540           "smpi_privatisation_regions");
541
542       s_smpi_privatisation_region_t privatisation_region =
543         mc_model_checker->process().read<s_smpi_privatisation_region_t>(
544           remote(remote_smpi_privatisation_regions + process_index));
545
546       // Address translation in the privaization segment:
547       size_t offset = address.address() - (std::uint64_t)info->start_rw;
548       address = remote((char*)privatisation_region.address + offset);
549     }
550   }
551
552   if (this->is_self()) {
553     if (mode == simgrid::mc::AddressSpace::Lazy)
554       return (void*)address.address();
555     else {
556       memcpy(buffer, (void*)address.address(), size);
557       return buffer;
558     }
559   } else {
560     if (pread_whole(this->memory_file, buffer, size, (off_t) address.address()) < 0)
561       xbt_die("Read from process %lli failed", (long long) this->pid_);
562     return buffer;
563   }
564 }
565
566 /** Write data to a process memory
567  *
568  *  @param process the process
569  *  @param local   local memory address (source)
570  *  @param remote  target process memory address (target)
571  *  @param len     data size
572  */
573 void Process::write_bytes(const void* buffer, size_t len, remote_ptr<void> address)
574 {
575   if (this->is_self()) {
576     memcpy((void*)address.address(), buffer, len);
577   } else {
578     if (pwrite_whole(this->memory_file, buffer, len, address.address()) < 0)
579       xbt_die("Write to process %lli failed", (long long) this->pid_);
580   }
581 }
582
583 void Process::clear_bytes(remote_ptr<void> address, size_t len)
584 {
585   if (this->is_self()) {
586     memset((void*)address.address(), 0, len);
587   } else {
588     pthread_once(&zero_buffer_flag, MC_zero_buffer_init);
589     while (len) {
590       size_t s = len > zero_buffer_size ? zero_buffer_size : len;
591       this->write_bytes(zero_buffer, s, address);
592       address = remote((char*) address.address() + s);
593       len -= s;
594     }
595   }
596 }
597
598 void Process::ignore_region(std::uint64_t addr, std::size_t size)
599 {
600   IgnoredRegion region;
601   region.addr = addr;
602   region.size = size;
603
604   if (ignored_regions_.empty()) {
605     ignored_regions_.push_back(region);
606     return;
607   }
608
609   unsigned int cursor = 0;
610   IgnoredRegion* current_region = nullptr;
611
612   int start = 0;
613   int end = ignored_regions_.size() - 1;
614   while (start <= end) {
615     cursor = (start + end) / 2;
616     current_region = &ignored_regions_[cursor];
617     if (current_region->addr == addr) {
618       if (current_region->size == size)
619         return;
620       else if (current_region->size < size)
621         start = cursor + 1;
622       else
623         end = cursor - 1;
624     } else if (current_region->addr < addr)
625       start = cursor + 1;
626     else
627       end = cursor - 1;
628   }
629
630   std::size_t position;
631   if (current_region->addr == addr) {
632     if (current_region->size < size) {
633       position = cursor + 1;
634     } else {
635       position = cursor;
636     }
637   } else if (current_region->addr < addr) {
638     position = cursor + 1;
639   } else {
640     position = cursor;
641   }
642   ignored_regions_.insert(
643     ignored_regions_.begin() + position, region);
644 }
645
646 }
647 }