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