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