src/mc/mc_process.c

   1 #include <assert.h>
   2 #include <stddef.h>
   3 #include <stdbool.h>
   4 #include <stdint.h>
   5 #include <errno.h>
   6
   7 #include <sys/types.h>
   8 #include <fcntl.h>
   9 #include <unistd.h>
  10 #include <regex.h>
  11 #include <sys/mman.h> // PROT_*
  12
  13 #include <pthread.h>
  14
  15 #include <libgen.h>
  16
  17 #include <libunwind.h>
  18 #include <libunwind-ptrace.h>
  19
  20 #include <xbt/mmalloc.h>
  21
  22 #include "mc_process.h"
  23 #include "mc_object_info.h"
  24 #include "mc_address_space.h"
  25 #include "mc_unw.h"
  26 #include "mc_snapshot.h"
  27 #include "mc_ignore.h"
  28
  29 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_process, mc,
  30                                 "MC process information");
  31
  32 static void MC_process_init_memory_map_info(mc_process_t process);
  33 static void MC_process_open_memory_file(mc_process_t process);
  34
  35 // ***** Destructor callbacks
  36
  37 // ***** mc_address_space methods for mc_process
  38
  39 static mc_process_t MC_process_get_process(mc_process_t p) {
  40   return p;
  41 }
  42
  43 static const s_mc_address_space_class_t mc_process_class = {
  44   .read = (void*) &MC_process_read,
  45   .get_process = (void*) MC_process_get_process
  46 };
  47
  48 bool MC_is_process(mc_address_space_t p)
  49 {
  50   return p->address_space_class == &mc_process_class;
  51 }
  52
  53 // ***** mc_process
  54
  55 void MC_process_init(mc_process_t process, pid_t pid, int sockfd)
  56 {
  57   process->address_space.address_space_class = &mc_process_class;
  58   process->process_flags = MC_PROCESS_NO_FLAG;
  59   process->socket = sockfd;
  60   process->pid = pid;
  61   if (pid==getpid())
  62     process->process_flags |= MC_PROCESS_SELF_FLAG;
  63   process->running = true;
  64   process->status = 0;
  65   process->memory_map = MC_get_memory_map(pid);
  66   process->memory_file = -1;
  67   process->cache_flags = 0;
  68   process->heap = NULL;
  69   process->heap_info = NULL;
  70   MC_process_init_memory_map_info(process);
  71   MC_process_open_memory_file(process);
  72
  73   // Read std_heap (is a struct mdesc*):
  74   dw_variable_t std_heap_var = MC_process_find_variable_by_name(process, "std_heap");
  75   if (!std_heap_var)
  76     xbt_die("No heap information in the target process");
  77   if(!std_heap_var->address)
  78     xbt_die("No constant address for this variable");
  79   MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE,
  80     &process->heap_address, std_heap_var->address, sizeof(struct mdesc*),
  81     MC_PROCESS_INDEX_DISABLED);
  82
  83   process->checkpoint_ignore = MC_checkpoint_ignore_new();
  84
  85   process->unw_addr_space = unw_create_addr_space(&mc_unw_accessors  , __BYTE_ORDER);
  86   if (process->process_flags & MC_PROCESS_SELF_FLAG) {
  87     process->unw_underlying_addr_space = unw_local_addr_space;
  88     process->unw_underlying_context = NULL;
  89   } else {
  90     process->unw_underlying_addr_space = unw_create_addr_space(&mc_unw_vmread_accessors, __BYTE_ORDER);
  91     process->unw_underlying_context = _UPT_create(pid);
  92   }
  93 }
  94
  95 void MC_process_clear(mc_process_t process)
  96 {
  97   process->address_space.address_space_class = NULL;
  98   process->process_flags = MC_PROCESS_NO_FLAG;
  99   process->pid = 0;
 100
 101   MC_free_memory_map(process->memory_map);
 102   process->memory_map = NULL;
 103
 104   process->maestro_stack_start = NULL;
 105   process->maestro_stack_end = NULL;
 106
 107   xbt_dynar_free(&process->checkpoint_ignore);
 108
 109   size_t i;
 110   for (i=0; i!=process->object_infos_size; ++i) {
 111     MC_free_object_info(&process->object_infos[i]);
 112   }
 113   free(process->object_infos);
 114   process->object_infos = NULL;
 115   process->object_infos_size = 0;
 116   if (process->memory_file >= 0) {
 117     close(process->memory_file);
 118   }
 119
 120   if (process->unw_underlying_addr_space != unw_local_addr_space) {
 121     unw_destroy_addr_space(process->unw_underlying_addr_space);
 122     _UPT_destroy(process->unw_underlying_context);
 123   }
 124   process->unw_underlying_context = NULL;
 125   process->unw_underlying_addr_space = NULL;
 126
 127   unw_destroy_addr_space(process->unw_addr_space);
 128   process->unw_addr_space = NULL;
 129
 130   process->cache_flags = 0;
 131
 132   free(process->heap);
 133   process->heap = NULL;
 134
 135   free(process->heap_info);
 136   process->heap_info = NULL;
 137 }
 138
 139 void MC_process_refresh_heap(mc_process_t process)
 140 {
 141   assert(!MC_process_is_self(process));
 142   // Read/dereference/refresh the std_heap pointer:
 143   if (!process->heap) {
 144     xbt_mheap_t oldheap  = mmalloc_get_current_heap();
 145     MC_SET_MC_HEAP;
 146     process->heap = malloc(sizeof(struct mdesc));
 147     mmalloc_set_current_heap(oldheap);
 148   }
 149   MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE,
 150     process->heap, process->heap_address, sizeof(struct mdesc),
 151     MC_PROCESS_INDEX_DISABLED
 152     );
 153 }
 154
 155 void MC_process_refresh_malloc_info(mc_process_t process)
 156 {
 157   assert(!MC_process_is_self(process));
 158   if (!process->cache_flags & MC_PROCESS_CACHE_FLAG_HEAP)
 159     MC_process_refresh_heap(process);
 160   // Refresh process->heapinfo:
 161   size_t malloc_info_bytesize = process->heap->heaplimit * sizeof(malloc_info);
 162
 163   xbt_mheap_t oldheap  = mmalloc_get_current_heap();
 164   MC_SET_MC_HEAP;
 165   process->heap_info = (malloc_info*) realloc(process->heap_info,
 166     malloc_info_bytesize);
 167   mmalloc_set_current_heap(oldheap);
 168
 169   MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE,
 170     process->heap_info,
 171     process->heap->heapinfo, malloc_info_bytesize,
 172     MC_PROCESS_INDEX_DISABLED);
 173 }
 174
 175 #define SO_RE "\\.so[\\.0-9]*$"
 176 #define VERSION_RE "-[\\.0-9]*$"
 177
 178 const char* FILTERED_LIBS[] = {
 179   "libstdc++",
 180   "libc++",
 181   "libm",
 182   "libgcc_s",
 183   "libpthread",
 184   "libunwind",
 185   "libunwind-x86_64",
 186   "libunwind-x86",
 187   "libunwind-ptrace",
 188   "libdw",
 189   "libdl",
 190   "librt",
 191   "liblzma",
 192   "libelf",
 193   "libbz2",
 194   "libz",
 195   "libelf",
 196   "libc",
 197   "ld"
 198 };
 199
 200 static bool MC_is_simgrid_lib(const char* libname)
 201 {
 202   return !strcmp(libname, "libsimgrid");
 203 }
 204
 205 static bool MC_is_filtered_lib(const char* libname)
 206 {
 207   const size_t n = sizeof(FILTERED_LIBS) / sizeof(const char*);
 208   size_t i;
 209   for (i=0; i!=n; ++i)
 210     if (strcmp(libname, FILTERED_LIBS[i])==0)
 211       return true;
 212   return false;
 213 }
 214
 215 struct s_mc_memory_map_re {
 216   regex_t so_re;
 217   regex_t version_re;
 218 };
 219
 220 static char* MC_get_lib_name(const char* pathname, struct s_mc_memory_map_re* res) {
 221   const char* map_basename = basename((char*) pathname);
 222
 223   regmatch_t match;
 224   if(regexec(&res->so_re, map_basename, 1, &match, 0))
 225     return NULL;
 226
 227   char* libname = strndup(map_basename, match.rm_so);
 228
 229   // Strip the version suffix:
 230   if(libname && !regexec(&res->version_re, libname, 1, &match, 0)) {
 231     char* temp = libname;
 232     libname = strndup(temp, match.rm_so);
 233     free(temp);
 234   }
 235
 236   return libname;
 237 }
 238
 239 /** @brief Finds the range of the different memory segments and binary paths */
 240 static void MC_process_init_memory_map_info(mc_process_t process)
 241 {
 242   XBT_DEBUG("Get debug information ...");
 243   process->maestro_stack_start = NULL;
 244   process->maestro_stack_end = NULL;
 245   process->object_infos = NULL;
 246   process->object_infos_size = 0;
 247   process->binary_info = NULL;
 248   process->libsimgrid_info = NULL;
 249
 250   struct s_mc_memory_map_re res;
 251
 252   if(regcomp(&res.so_re, SO_RE, 0) || regcomp(&res.version_re, VERSION_RE, 0))
 253     xbt_die(".so regexp did not compile");
 254
 255   memory_map_t maps = process->memory_map;
 256
 257   const char* current_name = NULL;
 258
 259   size_t i = 0;
 260   for (i=0; i < maps->mapsize; i++) {
 261     map_region_t reg = &(maps->regions[i]);
 262     const char* pathname = maps->regions[i].pathname;
 263
 264     // Nothing to do
 265     if (maps->regions[i].pathname == NULL) {
 266       current_name = NULL;
 267       continue;
 268     }
 269
 270     // [stack], [vvar], [vsyscall], [vdso] ...
 271     if (pathname[0] == '[') {
 272       if ((reg->prot & PROT_WRITE) && !memcmp(pathname, "[stack]", 7)) {
 273         process->maestro_stack_start = reg->start_addr;
 274         process->maestro_stack_end = reg->end_addr;
 275       }
 276       current_name = NULL;
 277       continue;
 278     }
 279
 280     if (current_name && strcmp(current_name, pathname)==0)
 281       continue;
 282
 283     current_name = pathname;
 284     if (!(reg->prot & PROT_READ) && (reg->prot & PROT_EXEC))
 285       continue;
 286
 287     const bool is_executable = !i;
 288     char* libname = NULL;
 289     if (!is_executable) {
 290       libname = MC_get_lib_name(pathname, &res);
 291       if(!libname)
 292         continue;
 293       if (MC_is_filtered_lib(libname)) {
 294         free(libname);
 295         continue;
 296       }
 297     }
 298
 299     mc_object_info_t info =
 300       MC_find_object_info(process->memory_map, pathname, is_executable);
 301     process->object_infos = (mc_object_info_t*) realloc(process->object_infos,
 302       (process->object_infos_size+1) * sizeof(mc_object_info_t*));
 303     process->object_infos[process->object_infos_size] = info;
 304     process->object_infos_size++;
 305     if (is_executable)
 306       process->binary_info = info;
 307     else if (libname && MC_is_simgrid_lib(libname))
 308       process->libsimgrid_info = info;
 309     free(libname);
 310   }
 311
 312   regfree(&res.so_re);
 313   regfree(&res.version_re);
 314
 315   // Resolve time (including accress differents objects):
 316   for (i=0; i!=process->object_infos_size; ++i)
 317     MC_post_process_object_info(process, process->object_infos[i]);
 318
 319   xbt_assert(process->maestro_stack_start, "Did not find maestro_stack_start");
 320   xbt_assert(process->maestro_stack_end, "Did not find maestro_stack_end");
 321
 322   XBT_DEBUG("Get debug information done !");
 323 }
 324
 325 mc_object_info_t MC_process_find_object_info(mc_process_t process, const void *addr)
 326 {
 327   size_t i;
 328   for (i = 0; i != process->object_infos_size; ++i) {
 329     if (addr >= (void *) process->object_infos[i]->start
 330         && addr <= (void *) process->object_infos[i]->end) {
 331       return process->object_infos[i];
 332     }
 333   }
 334   return NULL;
 335 }
 336
 337 mc_object_info_t MC_process_find_object_info_exec(mc_process_t process, const void *addr)
 338 {
 339   size_t i;
 340   for (i = 0; i != process->object_infos_size; ++i) {
 341     if (addr >= (void *) process->object_infos[i]->start_exec
 342         && addr <= (void *) process->object_infos[i]->end_exec) {
 343       return process->object_infos[i];
 344     }
 345   }
 346   return NULL;
 347 }
 348
 349 mc_object_info_t MC_process_find_object_info_rw(mc_process_t process, const void *addr)
 350 {
 351   size_t i;
 352   for (i = 0; i != process->object_infos_size; ++i) {
 353     if (addr >= (void *) process->object_infos[i]->start_rw
 354         && addr <= (void *) process->object_infos[i]->end_rw) {
 355       return process->object_infos[i];
 356     }
 357   }
 358   return NULL;
 359 }
 360
 361 // Functions, variables…
 362
 363 dw_frame_t MC_process_find_function(mc_process_t process, const void *ip)
 364 {
 365   mc_object_info_t info = MC_process_find_object_info_exec(process, ip);
 366   if (info == NULL)
 367     return NULL;
 368   else
 369     return MC_file_object_info_find_function(info, ip);
 370 }
 371
 372 dw_variable_t MC_process_find_variable_by_name(mc_process_t process, const char* name)
 373 {
 374   const size_t n = process->object_infos_size;
 375   size_t i;
 376   for (i=0; i!=n; ++i) {
 377     mc_object_info_t info =process->object_infos[i];
 378     dw_variable_t var = MC_file_object_info_find_variable_by_name(info, name);
 379     if (var)
 380       return var;
 381   }
 382   return NULL;
 383 }
 384
 385 // ***** Memory access
 386
 387 int MC_process_vm_open(pid_t pid, int flags)
 388 {
 389   const size_t buffer_size = 30;
 390   char buffer[buffer_size];
 391   int res = snprintf(buffer, buffer_size, "/proc/%lli/mem", (long long) pid);
 392   if (res < 0 || res >= buffer_size) {
 393     errno = ENAMETOOLONG;
 394     return -1;
 395   }
 396   return open(buffer, flags);
 397 }
 398
 399 static void MC_process_open_memory_file(mc_process_t process)
 400 {
 401   if (MC_process_is_self(process) || process->memory_file >= 0)
 402     return;
 403
 404   int fd = MC_process_vm_open(process->pid, O_RDWR);
 405   if (fd<0)
 406     xbt_die("Could not open file for process virtual address space");
 407   process->memory_file = fd;
 408 }
 409
 410 static ssize_t pread_whole(int fd, void *buf, size_t count, off_t offset)
 411 {
 412   char* buffer = (char*) buf;
 413   ssize_t real_count = count;
 414   while (count) {
 415     ssize_t res = pread(fd, buffer, count, offset);
 416     if (res > 0) {
 417       count  -= res;
 418       buffer += res;
 419       offset += res;
 420     } else if (res==0) {
 421       return -1;
 422     } else if (errno != EINTR) {
 423       return -1;
 424     }
 425   }
 426   return real_count;
 427 }
 428
 429 static ssize_t pwrite_whole(int fd, const void *buf, size_t count, off_t offset)
 430 {
 431   const char* buffer = (const char*) buf;
 432   ssize_t real_count = count;
 433   while (count) {
 434     ssize_t res = pwrite(fd, buffer, count, offset);
 435     if (res > 0) {
 436       count  -= res;
 437       buffer += res;
 438       offset += res;
 439     } else if (res==0) {
 440       return -1;
 441     } else if (errno != EINTR) {
 442       return -1;
 443     }
 444   }
 445   return real_count;
 446 }
 447
 448 const void* MC_process_read(mc_process_t process, e_adress_space_read_flags_t flags,
 449   void* local, const void* remote, size_t len,
 450   int process_index)
 451 {
 452   if (process_index != MC_PROCESS_INDEX_DISABLED) {
 453     mc_object_info_t info = MC_process_find_object_info_rw(process, remote);
 454     // Segment overlap is not handled.
 455     if (MC_object_info_is_privatized(info)) {
 456       if (process_index < 0)
 457         xbt_die("Missing process index");
 458       // Address translation in the privaization segment:
 459       size_t offset = (const char*) remote - info->start_rw;
 460       remote = (const char*) remote - offset;
 461     }
 462   }
 463
 464   if (MC_process_is_self(process)) {
 465     if (flags & MC_ADDRESS_SPACE_READ_FLAGS_LAZY)
 466       return remote;
 467     else {
 468       memcpy(local, remote, len);
 469       return local;
 470     }
 471   } else {
 472     if (pread_whole(process->memory_file, local, len, (off_t) remote) < 0)
 473       xbt_die("Read from process %lli failed", (long long) process->pid);
 474     return local;
 475   }
 476 }
 477
 478 void MC_process_write(mc_process_t process, const void* local, void* remote, size_t len)
 479 {
 480   if (MC_process_is_self(process)) {
 481     memcpy(remote, local, len);
 482   } else {
 483     if (pwrite_whole(process->memory_file, local, len, (off_t) remote) < 0)
 484       xbt_die("Write to process %lli failed", (long long) process->pid);
 485   }
 486 }
 487
 488 static pthread_once_t zero_buffer_flag = PTHREAD_ONCE_INIT;
 489 static const void* zero_buffer;
 490 static const int zero_buffer_size = 10 * 4096;
 491
 492 static void MC_zero_buffer_init(void)
 493 {
 494   int fd = open("/dev/zero", O_RDONLY);
 495   if (fd<0)
 496     xbt_die("Could not open /dev/zero");
 497   zero_buffer = mmap(NULL, zero_buffer_size, PROT_READ, MAP_SHARED, fd, 0);
 498   if (zero_buffer == MAP_FAILED)
 499     xbt_die("Could not map the zero buffer");
 500   close(fd);
 501 }
 502
 503 void MC_process_clear_memory(mc_process_t process, void* remote, size_t len)
 504 {
 505   if (MC_process_is_self(process)) {
 506     memset(remote, 0, len);
 507   } else {
 508     pthread_once(&zero_buffer_flag, MC_zero_buffer_init);
 509     while (len) {
 510       size_t s = len > zero_buffer_size ? zero_buffer_size : len;
 511       MC_process_write(process, zero_buffer, remote, s);
 512       remote = (char*) remote + s;
 513       len -= s;
 514     }
 515   }
 516 }