1 /*
   2  * Copyright (c) 2001, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/vmSymbols.hpp"
  27 #include "logging/log.hpp"
  28 #include "memory/allocation.inline.hpp"
  29 #include "memory/resourceArea.hpp"
  30 #include "oops/oop.inline.hpp"
  31 #include "os_windows.inline.hpp"
  32 #include "runtime/handles.inline.hpp"
  33 #include "runtime/os.hpp"
  34 #include "runtime/perfMemory.hpp"
  35 #include "services/memTracker.hpp"
  36 #include "utilities/exceptions.hpp"
  37 
  38 #include <windows.h>
  39 #include <sys/types.h>
  40 #include <sys/stat.h>
  41 #include <errno.h>
  42 #include <lmcons.h>
  43 
  44 typedef BOOL (WINAPI *SetSecurityDescriptorControlFnPtr)(
  45    IN PSECURITY_DESCRIPTOR pSecurityDescriptor,
  46    IN SECURITY_DESCRIPTOR_CONTROL ControlBitsOfInterest,
  47    IN SECURITY_DESCRIPTOR_CONTROL ControlBitsToSet);
  48 
  49 // Standard Memory Implementation Details
  50 
  51 // create the PerfData memory region in standard memory.
  52 //
  53 static char* create_standard_memory(size_t size) {
  54 
  55   // allocate an aligned chuck of memory
  56   char* mapAddress = os::reserve_memory(size);
  57 
  58   if (mapAddress == NULL) {
  59     return NULL;
  60   }
  61 
  62   // commit memory
  63   if (!os::commit_memory(mapAddress, size, !ExecMem)) {
  64     if (PrintMiscellaneous && Verbose) {
  65       warning("Could not commit PerfData memory\n");
  66     }
  67     os::release_memory(mapAddress, size);
  68     return NULL;
  69   }
  70 
  71   return mapAddress;
  72 }
  73 
  74 // delete the PerfData memory region
  75 //
  76 static void delete_standard_memory(char* addr, size_t size) {
  77 
  78   // there are no persistent external resources to cleanup for standard
  79   // memory. since DestroyJavaVM does not support unloading of the JVM,
  80   // cleanup of the memory resource is not performed. The memory will be
  81   // reclaimed by the OS upon termination of the process.
  82   //
  83   return;
  84 
  85 }
  86 
  87 // save the specified memory region to the given file
  88 //
  89 static void save_memory_to_file(char* addr, size_t size) {
  90 
  91   const char* destfile = PerfMemory::get_perfdata_file_path();
  92   assert(destfile[0] != '\0', "invalid Perfdata file path");
  93 
  94   int fd = ::_open(destfile, _O_BINARY|_O_CREAT|_O_WRONLY|_O_TRUNC,
  95                    _S_IREAD|_S_IWRITE);
  96 
  97   if (fd == OS_ERR) {
  98     if (PrintMiscellaneous && Verbose) {
  99       warning("Could not create Perfdata save file: %s: %s\n",
 100               destfile, os::strerror(errno));
 101     }
 102   } else {
 103     for (size_t remaining = size; remaining > 0;) {
 104 
 105       int nbytes = ::_write(fd, addr, (unsigned int)remaining);
 106       if (nbytes == OS_ERR) {
 107         if (PrintMiscellaneous && Verbose) {
 108           warning("Could not write Perfdata save file: %s: %s\n",
 109                   destfile, os::strerror(errno));
 110         }
 111         break;
 112       }
 113 
 114       remaining -= (size_t)nbytes;
 115       addr += nbytes;
 116     }
 117 
 118     int result = ::_close(fd);
 119     if (PrintMiscellaneous && Verbose) {
 120       if (result == OS_ERR) {
 121         warning("Could not close %s: %s\n", destfile, os::strerror(errno));
 122       }
 123     }
 124   }
 125 
 126   FREE_C_HEAP_ARRAY(char, destfile);
 127 }
 128 
 129 // Shared Memory Implementation Details
 130 
 131 // Note: the win32 shared memory implementation uses two objects to represent
 132 // the shared memory: a windows kernel based file mapping object and a backing
 133 // store file. On windows, the name space for shared memory is a kernel
 134 // based name space that is disjoint from other win32 name spaces. Since Java
 135 // is unaware of this name space, a parallel file system based name space is
 136 // maintained, which provides a common file system based shared memory name
 137 // space across the supported platforms and one that Java apps can deal with
 138 // through simple file apis.
 139 //
 140 // For performance and resource cleanup reasons, it is recommended that the
 141 // user specific directory and the backing store file be stored in either a
 142 // RAM based file system or a local disk based file system. Network based
 143 // file systems are not recommended for performance reasons. In addition,
 144 // use of SMB network based file systems may result in unsuccesful cleanup
 145 // of the disk based resource on exit of the VM. The Windows TMP and TEMP
 146 // environement variables, as used by the GetTempPath() Win32 API (see
 147 // os::get_temp_directory() in os_win32.cpp), control the location of the
 148 // user specific directory and the shared memory backing store file.
 149 
 150 static HANDLE sharedmem_fileMapHandle = NULL;
 151 static HANDLE sharedmem_fileHandle = INVALID_HANDLE_VALUE;
 152 static char*  sharedmem_fileName = NULL;
 153 
 154 // return the user specific temporary directory name.
 155 //
 156 // the caller is expected to free the allocated memory.
 157 //
 158 static char* get_user_tmp_dir(const char* user) {
 159 
 160   const char* tmpdir = os::get_temp_directory();
 161   const char* perfdir = PERFDATA_NAME;
 162   size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3;
 163   char* dirname = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
 164 
 165   // construct the path name to user specific tmp directory
 166   _snprintf(dirname, nbytes, "%s\\%s_%s", tmpdir, perfdir, user);
 167 
 168   return dirname;
 169 }
 170 
 171 // convert the given file name into a process id. if the file
 172 // does not meet the file naming constraints, return 0.
 173 //
 174 static int filename_to_pid(const char* filename) {
 175 
 176   // a filename that doesn't begin with a digit is not a
 177   // candidate for conversion.
 178   //
 179   if (!isdigit(*filename)) {
 180     return 0;
 181   }
 182 
 183   // check if file name can be converted to an integer without
 184   // any leftover characters.
 185   //
 186   char* remainder = NULL;
 187   errno = 0;
 188   int pid = (int)strtol(filename, &remainder, 10);
 189 
 190   if (errno != 0) {
 191     return 0;
 192   }
 193 
 194   // check for left over characters. If any, then the filename is
 195   // not a candidate for conversion.
 196   //
 197   if (remainder != NULL && *remainder != '\0') {
 198     return 0;
 199   }
 200 
 201   // successful conversion, return the pid
 202   return pid;
 203 }
 204 
 205 // check if the given path is considered a secure directory for
 206 // the backing store files. Returns true if the directory exists
 207 // and is considered a secure location. Returns false if the path
 208 // is a symbolic link or if an error occurred.
 209 //
 210 static bool is_directory_secure(const char* path) {
 211 
 212   DWORD fa;
 213 
 214   fa = GetFileAttributes(path);
 215   if (fa == 0xFFFFFFFF) {
 216     DWORD lasterror = GetLastError();
 217     if (lasterror == ERROR_FILE_NOT_FOUND) {
 218       return false;
 219     }
 220     else {
 221       // unexpected error, declare the path insecure
 222       if (PrintMiscellaneous && Verbose) {
 223         warning("could not get attributes for file %s: ",
 224                 " lasterror = %d\n", path, lasterror);
 225       }
 226       return false;
 227     }
 228   }
 229 
 230   if (fa & FILE_ATTRIBUTE_REPARSE_POINT) {
 231     // we don't accept any redirection for the user specific directory
 232     // so declare the path insecure. This may be too conservative,
 233     // as some types of reparse points might be acceptable, but it
 234     // is probably more secure to avoid these conditions.
 235     //
 236     if (PrintMiscellaneous && Verbose) {
 237       warning("%s is a reparse point\n", path);
 238     }
 239     return false;
 240   }
 241 
 242   if (fa & FILE_ATTRIBUTE_DIRECTORY) {
 243     // this is the expected case. Since windows supports symbolic
 244     // links to directories only, not to files, there is no need
 245     // to check for open write permissions on the directory. If the
 246     // directory has open write permissions, any files deposited that
 247     // are not expected will be removed by the cleanup code.
 248     //
 249     return true;
 250   }
 251   else {
 252     // this is either a regular file or some other type of file,
 253     // any of which are unexpected and therefore insecure.
 254     //
 255     if (PrintMiscellaneous && Verbose) {
 256       warning("%s is not a directory, file attributes = "
 257               INTPTR_FORMAT "\n", path, fa);
 258     }
 259     return false;
 260   }
 261 }
 262 
 263 // return the user name for the owner of this process
 264 //
 265 // the caller is expected to free the allocated memory.
 266 //
 267 static char* get_user_name() {
 268 
 269   /* get the user name. This code is adapted from code found in
 270    * the jdk in src/windows/native/java/lang/java_props_md.c
 271    * java_props_md.c  1.29 02/02/06. According to the original
 272    * source, the call to GetUserName is avoided because of a resulting
 273    * increase in footprint of 100K.
 274    */
 275   char* user = getenv("USERNAME");
 276   char buf[UNLEN+1];
 277   DWORD buflen = sizeof(buf);
 278   if (user == NULL || strlen(user) == 0) {
 279     if (GetUserName(buf, &buflen)) {
 280       user = buf;
 281     }
 282     else {
 283       return NULL;
 284     }
 285   }
 286 
 287   char* user_name = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
 288   strcpy(user_name, user);
 289 
 290   return user_name;
 291 }
 292 
 293 // return the name of the user that owns the process identified by vmid.
 294 //
 295 // This method uses a slow directory search algorithm to find the backing
 296 // store file for the specified vmid and returns the user name, as determined
 297 // by the user name suffix of the hsperfdata_<username> directory name.
 298 //
 299 // the caller is expected to free the allocated memory.
 300 //
 301 static char* get_user_name_slow(int vmid) {
 302 
 303   // directory search
 304   char* latest_user = NULL;
 305   time_t latest_ctime = 0;
 306 
 307   const char* tmpdirname = os::get_temp_directory();
 308 
 309   DIR* tmpdirp = os::opendir(tmpdirname);
 310 
 311   if (tmpdirp == NULL) {
 312     return NULL;
 313   }
 314 
 315   // for each entry in the directory that matches the pattern hsperfdata_*,
 316   // open the directory and check if the file for the given vmid exists.
 317   // The file with the expected name and the latest creation date is used
 318   // to determine the user name for the process id.
 319   //
 320   struct dirent* dentry;
 321   errno = 0;
 322   while ((dentry = os::readdir(tmpdirp)) != NULL) {
 323 
 324     // check if the directory entry is a hsperfdata file
 325     if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
 326       continue;
 327     }
 328 
 329     char* usrdir_name = NEW_C_HEAP_ARRAY(char,
 330         strlen(tmpdirname) + strlen(dentry->d_name) + 2, mtInternal);
 331     strcpy(usrdir_name, tmpdirname);
 332     strcat(usrdir_name, "\\");
 333     strcat(usrdir_name, dentry->d_name);
 334 
 335     DIR* subdirp = os::opendir(usrdir_name);
 336 
 337     if (subdirp == NULL) {
 338       FREE_C_HEAP_ARRAY(char, usrdir_name);
 339       continue;
 340     }
 341 
 342     // Since we don't create the backing store files in directories
 343     // pointed to by symbolic links, we also don't follow them when
 344     // looking for the files. We check for a symbolic link after the
 345     // call to opendir in order to eliminate a small window where the
 346     // symlink can be exploited.
 347     //
 348     if (!is_directory_secure(usrdir_name)) {
 349       FREE_C_HEAP_ARRAY(char, usrdir_name);
 350       os::closedir(subdirp);
 351       continue;
 352     }
 353 
 354     struct dirent* udentry;
 355     errno = 0;
 356     while ((udentry = os::readdir(subdirp)) != NULL) {
 357 
 358       if (filename_to_pid(udentry->d_name) == vmid) {
 359         struct stat statbuf;
 360 
 361         char* filename = NEW_C_HEAP_ARRAY(char,
 362            strlen(usrdir_name) + strlen(udentry->d_name) + 2, mtInternal);
 363 
 364         strcpy(filename, usrdir_name);
 365         strcat(filename, "\\");
 366         strcat(filename, udentry->d_name);
 367 
 368         if (::stat(filename, &statbuf) == OS_ERR) {
 369            FREE_C_HEAP_ARRAY(char, filename);
 370            continue;
 371         }
 372 
 373         // skip over files that are not regular files.
 374         if ((statbuf.st_mode & S_IFMT) != S_IFREG) {
 375           FREE_C_HEAP_ARRAY(char, filename);
 376           continue;
 377         }
 378 
 379         // If we found a matching file with a newer creation time, then
 380         // save the user name. The newer creation time indicates that
 381         // we found a newer incarnation of the process associated with
 382         // vmid. Due to the way that Windows recycles pids and the fact
 383         // that we can't delete the file from the file system namespace
 384         // until last close, it is possible for there to be more than
 385         // one hsperfdata file with a name matching vmid (diff users).
 386         //
 387         // We no longer ignore hsperfdata files where (st_size == 0).
 388         // In this function, all we're trying to do is determine the
 389         // name of the user that owns the process associated with vmid
 390         // so the size doesn't matter. Very rarely, we have observed
 391         // hsperfdata files where (st_size == 0) and the st_size field
 392         // later becomes the expected value.
 393         //
 394         if (statbuf.st_ctime > latest_ctime) {
 395           char* user = strchr(dentry->d_name, '_') + 1;
 396 
 397           FREE_C_HEAP_ARRAY(char, latest_user);
 398           latest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
 399 
 400           strcpy(latest_user, user);
 401           latest_ctime = statbuf.st_ctime;
 402         }
 403 
 404         FREE_C_HEAP_ARRAY(char, filename);
 405       }
 406     }
 407     os::closedir(subdirp);
 408     FREE_C_HEAP_ARRAY(char, usrdir_name);
 409   }
 410   os::closedir(tmpdirp);
 411 
 412   return(latest_user);
 413 }
 414 
 415 // return the name of the user that owns the process identified by vmid.
 416 //
 417 // note: this method should only be used via the Perf native methods.
 418 // There are various costs to this method and limiting its use to the
 419 // Perf native methods limits the impact to monitoring applications only.
 420 //
 421 static char* get_user_name(int vmid) {
 422 
 423   // A fast implementation is not provided at this time. It's possible
 424   // to provide a fast process id to user name mapping function using
 425   // the win32 apis, but the default ACL for the process object only
 426   // allows processes with the same owner SID to acquire the process
 427   // handle (via OpenProcess(PROCESS_QUERY_INFORMATION)). It's possible
 428   // to have the JVM change the ACL for the process object to allow arbitrary
 429   // users to access the process handle and the process security token.
 430   // The security ramifications need to be studied before providing this
 431   // mechanism.
 432   //
 433   return get_user_name_slow(vmid);
 434 }
 435 
 436 // return the name of the shared memory file mapping object for the
 437 // named shared memory region for the given user name and vmid.
 438 //
 439 // The file mapping object's name is not the file name. It is a name
 440 // in a separate name space.
 441 //
 442 // the caller is expected to free the allocated memory.
 443 //
 444 static char *get_sharedmem_objectname(const char* user, int vmid) {
 445 
 446   // construct file mapping object's name, add 3 for two '_' and a
 447   // null terminator.
 448   int nbytes = (int)strlen(PERFDATA_NAME) + (int)strlen(user) + 3;
 449 
 450   // the id is converted to an unsigned value here because win32 allows
 451   // negative process ids. However, OpenFileMapping API complains
 452   // about a name containing a '-' characters.
 453   //
 454   nbytes += UINT_CHARS;
 455   char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
 456   _snprintf(name, nbytes, "%s_%s_%u", PERFDATA_NAME, user, vmid);
 457 
 458   return name;
 459 }
 460 
 461 // return the file name of the backing store file for the named
 462 // shared memory region for the given user name and vmid.
 463 //
 464 // the caller is expected to free the allocated memory.
 465 //
 466 static char* get_sharedmem_filename(const char* dirname, int vmid) {
 467 
 468   // add 2 for the file separator and a null terminator.
 469   size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
 470 
 471   char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
 472   _snprintf(name, nbytes, "%s\\%d", dirname, vmid);
 473 
 474   return name;
 475 }
 476 
 477 // remove file
 478 //
 479 // this method removes the file with the given file name.
 480 //
 481 // Note: if the indicated file is on an SMB network file system, this
 482 // method may be unsuccessful in removing the file.
 483 //
 484 static void remove_file(const char* dirname, const char* filename) {
 485 
 486   size_t nbytes = strlen(dirname) + strlen(filename) + 2;
 487   char* path = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
 488 
 489   strcpy(path, dirname);
 490   strcat(path, "\\");
 491   strcat(path, filename);
 492 
 493   if (::unlink(path) == OS_ERR) {
 494     if (PrintMiscellaneous && Verbose) {
 495       if (errno != ENOENT) {
 496         warning("Could not unlink shared memory backing"
 497                 " store file %s : %s\n", path, os::strerror(errno));
 498       }
 499     }
 500   }
 501 
 502   FREE_C_HEAP_ARRAY(char, path);
 503 }
 504 
 505 // returns true if the process represented by pid is alive, otherwise
 506 // returns false. the validity of the result is only accurate if the
 507 // target process is owned by the same principal that owns this process.
 508 // this method should not be used if to test the status of an otherwise
 509 // arbitrary process unless it is know that this process has the appropriate
 510 // privileges to guarantee a result valid.
 511 //
 512 static bool is_alive(int pid) {
 513 
 514   HANDLE ph = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid);
 515   if (ph == NULL) {
 516     // the process does not exist.
 517     if (PrintMiscellaneous && Verbose) {
 518       DWORD lastError = GetLastError();
 519       if (lastError != ERROR_INVALID_PARAMETER) {
 520         warning("OpenProcess failed: %d\n", GetLastError());
 521       }
 522     }
 523     return false;
 524   }
 525 
 526   DWORD exit_status;
 527   if (!GetExitCodeProcess(ph, &exit_status)) {
 528     if (PrintMiscellaneous && Verbose) {
 529       warning("GetExitCodeProcess failed: %d\n", GetLastError());
 530     }
 531     CloseHandle(ph);
 532     return false;
 533   }
 534 
 535   CloseHandle(ph);
 536   return (exit_status == STILL_ACTIVE) ? true : false;
 537 }
 538 
 539 // check if the file system is considered secure for the backing store files
 540 //
 541 static bool is_filesystem_secure(const char* path) {
 542 
 543   char root_path[MAX_PATH];
 544   char fs_type[MAX_PATH];
 545 
 546   if (PerfBypassFileSystemCheck) {
 547     if (PrintMiscellaneous && Verbose) {
 548       warning("bypassing file system criteria checks for %s\n", path);
 549     }
 550     return true;
 551   }
 552 
 553   char* first_colon = strchr((char *)path, ':');
 554   if (first_colon == NULL) {
 555     if (PrintMiscellaneous && Verbose) {
 556       warning("expected device specifier in path: %s\n", path);
 557     }
 558     return false;
 559   }
 560 
 561   size_t len = (size_t)(first_colon - path);
 562   assert(len + 2 <= MAX_PATH, "unexpected device specifier length");
 563   strncpy(root_path, path, len + 1);
 564   root_path[len + 1] = '\\';
 565   root_path[len + 2] = '\0';
 566 
 567   // check that we have something like "C:\" or "AA:\"
 568   assert(strlen(root_path) >= 3, "device specifier too short");
 569   assert(strchr(root_path, ':') != NULL, "bad device specifier format");
 570   assert(strchr(root_path, '\\') != NULL, "bad device specifier format");
 571 
 572   DWORD maxpath;
 573   DWORD flags;
 574 
 575   if (!GetVolumeInformation(root_path, NULL, 0, NULL, &maxpath,
 576                             &flags, fs_type, MAX_PATH)) {
 577     // we can't get information about the volume, so assume unsafe.
 578     if (PrintMiscellaneous && Verbose) {
 579       warning("could not get device information for %s: "
 580               " path = %s: lasterror = %d\n",
 581               root_path, path, GetLastError());
 582     }
 583     return false;
 584   }
 585 
 586   if ((flags & FS_PERSISTENT_ACLS) == 0) {
 587     // file system doesn't support ACLs, declare file system unsafe
 588     if (PrintMiscellaneous && Verbose) {
 589       warning("file system type %s on device %s does not support"
 590               " ACLs\n", fs_type, root_path);
 591     }
 592     return false;
 593   }
 594 
 595   if ((flags & FS_VOL_IS_COMPRESSED) != 0) {
 596     // file system is compressed, declare file system unsafe
 597     if (PrintMiscellaneous && Verbose) {
 598       warning("file system type %s on device %s is compressed\n",
 599               fs_type, root_path);
 600     }
 601     return false;
 602   }
 603 
 604   return true;
 605 }
 606 
 607 // cleanup stale shared memory resources
 608 //
 609 // This method attempts to remove all stale shared memory files in
 610 // the named user temporary directory. It scans the named directory
 611 // for files matching the pattern ^$[0-9]*$. For each file found, the
 612 // process id is extracted from the file name and a test is run to
 613 // determine if the process is alive. If the process is not alive,
 614 // any stale file resources are removed.
 615 //
 616 static void cleanup_sharedmem_resources(const char* dirname) {
 617 
 618   // open the user temp directory
 619   DIR* dirp = os::opendir(dirname);
 620 
 621   if (dirp == NULL) {
 622     // directory doesn't exist, so there is nothing to cleanup
 623     return;
 624   }
 625 
 626   if (!is_directory_secure(dirname)) {
 627     // the directory is not secure, don't attempt any cleanup
 628     os::closedir(dirp);
 629     return;
 630   }
 631 
 632   // for each entry in the directory that matches the expected file
 633   // name pattern, determine if the file resources are stale and if
 634   // so, remove the file resources. Note, instrumented HotSpot processes
 635   // for this user may start and/or terminate during this search and
 636   // remove or create new files in this directory. The behavior of this
 637   // loop under these conditions is dependent upon the implementation of
 638   // opendir/readdir.
 639   //
 640   struct dirent* entry;
 641   errno = 0;
 642   while ((entry = os::readdir(dirp)) != NULL) {
 643 
 644     int pid = filename_to_pid(entry->d_name);
 645 
 646     if (pid == 0) {
 647 
 648       if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
 649 
 650         // attempt to remove all unexpected files, except "." and ".."
 651         remove_file(dirname, entry->d_name);
 652       }
 653 
 654       errno = 0;
 655       continue;
 656     }
 657 
 658     // we now have a file name that converts to a valid integer
 659     // that could represent a process id . if this process id
 660     // matches the current process id or the process is not running,
 661     // then remove the stale file resources.
 662     //
 663     // process liveness is detected by checking the exit status
 664     // of the process. if the process id is valid and the exit status
 665     // indicates that it is still running, the file file resources
 666     // are not removed. If the process id is invalid, or if we don't
 667     // have permissions to check the process status, or if the process
 668     // id is valid and the process has terminated, the the file resources
 669     // are assumed to be stale and are removed.
 670     //
 671     if (pid == os::current_process_id() || !is_alive(pid)) {
 672 
 673       // we can only remove the file resources. Any mapped views
 674       // of the file can only be unmapped by the processes that
 675       // opened those views and the file mapping object will not
 676       // get removed until all views are unmapped.
 677       //
 678       remove_file(dirname, entry->d_name);
 679     }
 680     errno = 0;
 681   }
 682   os::closedir(dirp);
 683 }
 684 
 685 // create a file mapping object with the requested name, and size
 686 // from the file represented by the given Handle object
 687 //
 688 static HANDLE create_file_mapping(const char* name, HANDLE fh, LPSECURITY_ATTRIBUTES fsa, size_t size) {
 689 
 690   DWORD lowSize = (DWORD)size;
 691   DWORD highSize = 0;
 692   HANDLE fmh = NULL;
 693 
 694   // Create a file mapping object with the given name. This function
 695   // will grow the file to the specified size.
 696   //
 697   fmh = CreateFileMapping(
 698                fh,                 /* HANDLE file handle for backing store */
 699                fsa,                /* LPSECURITY_ATTRIBUTES Not inheritable */
 700                PAGE_READWRITE,     /* DWORD protections */
 701                highSize,           /* DWORD High word of max size */
 702                lowSize,            /* DWORD Low word of max size */
 703                name);              /* LPCTSTR name for object */
 704 
 705   if (fmh == NULL) {
 706     if (PrintMiscellaneous && Verbose) {
 707       warning("CreateFileMapping failed, lasterror = %d\n", GetLastError());
 708     }
 709     return NULL;
 710   }
 711 
 712   if (GetLastError() == ERROR_ALREADY_EXISTS) {
 713 
 714     // a stale file mapping object was encountered. This object may be
 715     // owned by this or some other user and cannot be removed until
 716     // the other processes either exit or close their mapping objects
 717     // and/or mapped views of this mapping object.
 718     //
 719     if (PrintMiscellaneous && Verbose) {
 720       warning("file mapping already exists, lasterror = %d\n", GetLastError());
 721     }
 722 
 723     CloseHandle(fmh);
 724     return NULL;
 725   }
 726 
 727   return fmh;
 728 }
 729 
 730 
 731 // method to free the given security descriptor and the contained
 732 // access control list.
 733 //
 734 static void free_security_desc(PSECURITY_DESCRIPTOR pSD) {
 735 
 736   BOOL success, exists, isdefault;
 737   PACL pACL;
 738 
 739   if (pSD != NULL) {
 740 
 741     // get the access control list from the security descriptor
 742     success = GetSecurityDescriptorDacl(pSD, &exists, &pACL, &isdefault);
 743 
 744     // if an ACL existed and it was not a default acl, then it must
 745     // be an ACL we enlisted. free the resources.
 746     //
 747     if (success && exists && pACL != NULL && !isdefault) {
 748       FREE_C_HEAP_ARRAY(char, pACL);
 749     }
 750 
 751     // free the security descriptor
 752     FREE_C_HEAP_ARRAY(char, pSD);
 753   }
 754 }
 755 
 756 // method to free up a security attributes structure and any
 757 // contained security descriptors and ACL
 758 //
 759 static void free_security_attr(LPSECURITY_ATTRIBUTES lpSA) {
 760 
 761   if (lpSA != NULL) {
 762     // free the contained security descriptor and the ACL
 763     free_security_desc(lpSA->lpSecurityDescriptor);
 764     lpSA->lpSecurityDescriptor = NULL;
 765 
 766     // free the security attributes structure
 767     FREE_C_HEAP_OBJ(lpSA);
 768   }
 769 }
 770 
 771 // get the user SID for the process indicated by the process handle
 772 //
 773 static PSID get_user_sid(HANDLE hProcess) {
 774 
 775   HANDLE hAccessToken;
 776   PTOKEN_USER token_buf = NULL;
 777   DWORD rsize = 0;
 778 
 779   if (hProcess == NULL) {
 780     return NULL;
 781   }
 782 
 783   // get the process token
 784   if (!OpenProcessToken(hProcess, TOKEN_READ, &hAccessToken)) {
 785     if (PrintMiscellaneous && Verbose) {
 786       warning("OpenProcessToken failure: lasterror = %d \n", GetLastError());
 787     }
 788     return NULL;
 789   }
 790 
 791   // determine the size of the token structured needed to retrieve
 792   // the user token information from the access token.
 793   //
 794   if (!GetTokenInformation(hAccessToken, TokenUser, NULL, rsize, &rsize)) {
 795     DWORD lasterror = GetLastError();
 796     if (lasterror != ERROR_INSUFFICIENT_BUFFER) {
 797       if (PrintMiscellaneous && Verbose) {
 798         warning("GetTokenInformation failure: lasterror = %d,"
 799                 " rsize = %d\n", lasterror, rsize);
 800       }
 801       CloseHandle(hAccessToken);
 802       return NULL;
 803     }
 804   }
 805 
 806   token_buf = (PTOKEN_USER) NEW_C_HEAP_ARRAY(char, rsize, mtInternal);
 807 
 808   // get the user token information
 809   if (!GetTokenInformation(hAccessToken, TokenUser, token_buf, rsize, &rsize)) {
 810     if (PrintMiscellaneous && Verbose) {
 811       warning("GetTokenInformation failure: lasterror = %d,"
 812               " rsize = %d\n", GetLastError(), rsize);
 813     }
 814     FREE_C_HEAP_ARRAY(char, token_buf);
 815     CloseHandle(hAccessToken);
 816     return NULL;
 817   }
 818 
 819   DWORD nbytes = GetLengthSid(token_buf->User.Sid);
 820   PSID pSID = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
 821 
 822   if (!CopySid(nbytes, pSID, token_buf->User.Sid)) {
 823     if (PrintMiscellaneous && Verbose) {
 824       warning("GetTokenInformation failure: lasterror = %d,"
 825               " rsize = %d\n", GetLastError(), rsize);
 826     }
 827     FREE_C_HEAP_ARRAY(char, token_buf);
 828     FREE_C_HEAP_ARRAY(char, pSID);
 829     CloseHandle(hAccessToken);
 830     return NULL;
 831   }
 832 
 833   // close the access token.
 834   CloseHandle(hAccessToken);
 835   FREE_C_HEAP_ARRAY(char, token_buf);
 836 
 837   return pSID;
 838 }
 839 
 840 // structure used to consolidate access control entry information
 841 //
 842 typedef struct ace_data {
 843   PSID pSid;      // SID of the ACE
 844   DWORD mask;     // mask for the ACE
 845 } ace_data_t;
 846 
 847 
 848 // method to add an allow access control entry with the access rights
 849 // indicated in mask for the principal indicated in SID to the given
 850 // security descriptor. Much of the DACL handling was adapted from
 851 // the example provided here:
 852 //      http://support.microsoft.com/kb/102102/EN-US/
 853 //
 854 
 855 static bool add_allow_aces(PSECURITY_DESCRIPTOR pSD,
 856                            ace_data_t aces[], int ace_count) {
 857   PACL newACL = NULL;
 858   PACL oldACL = NULL;
 859 
 860   if (pSD == NULL) {
 861     return false;
 862   }
 863 
 864   BOOL exists, isdefault;
 865 
 866   // retrieve any existing access control list.
 867   if (!GetSecurityDescriptorDacl(pSD, &exists, &oldACL, &isdefault)) {
 868     if (PrintMiscellaneous && Verbose) {
 869       warning("GetSecurityDescriptor failure: lasterror = %d \n",
 870               GetLastError());
 871     }
 872     return false;
 873   }
 874 
 875   // get the size of the DACL
 876   ACL_SIZE_INFORMATION aclinfo;
 877 
 878   // GetSecurityDescriptorDacl may return true value for exists (lpbDaclPresent)
 879   // while oldACL is NULL for some case.
 880   if (oldACL == NULL) {
 881     exists = FALSE;
 882   }
 883 
 884   if (exists) {
 885     if (!GetAclInformation(oldACL, &aclinfo,
 886                            sizeof(ACL_SIZE_INFORMATION),
 887                            AclSizeInformation)) {
 888       if (PrintMiscellaneous && Verbose) {
 889         warning("GetAclInformation failure: lasterror = %d \n", GetLastError());
 890         return false;
 891       }
 892     }
 893   } else {
 894     aclinfo.AceCount = 0; // assume NULL DACL
 895     aclinfo.AclBytesFree = 0;
 896     aclinfo.AclBytesInUse = sizeof(ACL);
 897   }
 898 
 899   // compute the size needed for the new ACL
 900   // initial size of ACL is sum of the following:
 901   //   * size of ACL structure.
 902   //   * size of each ACE structure that ACL is to contain minus the sid
 903   //     sidStart member (DWORD) of the ACE.
 904   //   * length of the SID that each ACE is to contain.
 905   DWORD newACLsize = aclinfo.AclBytesInUse +
 906                         (sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD)) * ace_count;
 907   for (int i = 0; i < ace_count; i++) {
 908      assert(aces[i].pSid != 0, "pSid should not be 0");
 909      newACLsize += GetLengthSid(aces[i].pSid);
 910   }
 911 
 912   // create the new ACL
 913   newACL = (PACL) NEW_C_HEAP_ARRAY(char, newACLsize, mtInternal);
 914 
 915   if (!InitializeAcl(newACL, newACLsize, ACL_REVISION)) {
 916     if (PrintMiscellaneous && Verbose) {
 917       warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
 918     }
 919     FREE_C_HEAP_ARRAY(char, newACL);
 920     return false;
 921   }
 922 
 923   unsigned int ace_index = 0;
 924   // copy any existing ACEs from the old ACL (if any) to the new ACL.
 925   if (aclinfo.AceCount != 0) {
 926     while (ace_index < aclinfo.AceCount) {
 927       LPVOID ace;
 928       if (!GetAce(oldACL, ace_index, &ace)) {
 929         if (PrintMiscellaneous && Verbose) {
 930           warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
 931         }
 932         FREE_C_HEAP_ARRAY(char, newACL);
 933         return false;
 934       }
 935       if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceFlags && INHERITED_ACE) {
 936         // this is an inherited, allowed ACE; break from loop so we can
 937         // add the new access allowed, non-inherited ACE in the correct
 938         // position, immediately following all non-inherited ACEs.
 939         break;
 940       }
 941 
 942       // determine if the SID of this ACE matches any of the SIDs
 943       // for which we plan to set ACEs.
 944       int matches = 0;
 945       for (int i = 0; i < ace_count; i++) {
 946         if (EqualSid(aces[i].pSid, &(((ACCESS_ALLOWED_ACE *)ace)->SidStart))) {
 947           matches++;
 948           break;
 949         }
 950       }
 951 
 952       // if there are no SID matches, then add this existing ACE to the new ACL
 953       if (matches == 0) {
 954         if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
 955                     ((PACE_HEADER)ace)->AceSize)) {
 956           if (PrintMiscellaneous && Verbose) {
 957             warning("AddAce failure: lasterror = %d \n", GetLastError());
 958           }
 959           FREE_C_HEAP_ARRAY(char, newACL);
 960           return false;
 961         }
 962       }
 963       ace_index++;
 964     }
 965   }
 966 
 967   // add the passed-in access control entries to the new ACL
 968   for (int i = 0; i < ace_count; i++) {
 969     if (!AddAccessAllowedAce(newACL, ACL_REVISION,
 970                              aces[i].mask, aces[i].pSid)) {
 971       if (PrintMiscellaneous && Verbose) {
 972         warning("AddAccessAllowedAce failure: lasterror = %d \n",
 973                 GetLastError());
 974       }
 975       FREE_C_HEAP_ARRAY(char, newACL);
 976       return false;
 977     }
 978   }
 979 
 980   // now copy the rest of the inherited ACEs from the old ACL
 981   if (aclinfo.AceCount != 0) {
 982     // picking up at ace_index, where we left off in the
 983     // previous ace_index loop
 984     while (ace_index < aclinfo.AceCount) {
 985       LPVOID ace;
 986       if (!GetAce(oldACL, ace_index, &ace)) {
 987         if (PrintMiscellaneous && Verbose) {
 988           warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
 989         }
 990         FREE_C_HEAP_ARRAY(char, newACL);
 991         return false;
 992       }
 993       if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
 994                   ((PACE_HEADER)ace)->AceSize)) {
 995         if (PrintMiscellaneous && Verbose) {
 996           warning("AddAce failure: lasterror = %d \n", GetLastError());
 997         }
 998         FREE_C_HEAP_ARRAY(char, newACL);
 999         return false;
1000       }
1001       ace_index++;
1002     }
1003   }
1004 
1005   // add the new ACL to the security descriptor.
1006   if (!SetSecurityDescriptorDacl(pSD, TRUE, newACL, FALSE)) {
1007     if (PrintMiscellaneous && Verbose) {
1008       warning("SetSecurityDescriptorDacl failure:"
1009               " lasterror = %d \n", GetLastError());
1010     }
1011     FREE_C_HEAP_ARRAY(char, newACL);
1012     return false;
1013   }
1014 
1015   // if running on windows 2000 or later, set the automatic inheritance
1016   // control flags.
1017   SetSecurityDescriptorControlFnPtr _SetSecurityDescriptorControl;
1018   _SetSecurityDescriptorControl = (SetSecurityDescriptorControlFnPtr)
1019        GetProcAddress(GetModuleHandle(TEXT("advapi32.dll")),
1020                       "SetSecurityDescriptorControl");
1021 
1022   if (_SetSecurityDescriptorControl != NULL) {
1023     // We do not want to further propagate inherited DACLs, so making them
1024     // protected prevents that.
1025     if (!_SetSecurityDescriptorControl(pSD, SE_DACL_PROTECTED,
1026                                             SE_DACL_PROTECTED)) {
1027       if (PrintMiscellaneous && Verbose) {
1028         warning("SetSecurityDescriptorControl failure:"
1029                 " lasterror = %d \n", GetLastError());
1030       }
1031       FREE_C_HEAP_ARRAY(char, newACL);
1032       return false;
1033     }
1034   }
1035    // Note, the security descriptor maintains a reference to the newACL, not
1036    // a copy of it. Therefore, the newACL is not freed here. It is freed when
1037    // the security descriptor containing its reference is freed.
1038    //
1039    return true;
1040 }
1041 
1042 // method to create a security attributes structure, which contains a
1043 // security descriptor and an access control list comprised of 0 or more
1044 // access control entries. The method take an array of ace_data structures
1045 // that indicate the ACE to be added to the security descriptor.
1046 //
1047 // the caller must free the resources associated with the security
1048 // attributes structure created by this method by calling the
1049 // free_security_attr() method.
1050 //
1051 static LPSECURITY_ATTRIBUTES make_security_attr(ace_data_t aces[], int count) {
1052 
1053   // allocate space for a security descriptor
1054   PSECURITY_DESCRIPTOR pSD = (PSECURITY_DESCRIPTOR)
1055      NEW_C_HEAP_ARRAY(char, SECURITY_DESCRIPTOR_MIN_LENGTH, mtInternal);
1056 
1057   // initialize the security descriptor
1058   if (!InitializeSecurityDescriptor(pSD, SECURITY_DESCRIPTOR_REVISION)) {
1059     if (PrintMiscellaneous && Verbose) {
1060       warning("InitializeSecurityDescriptor failure: "
1061               "lasterror = %d \n", GetLastError());
1062     }
1063     free_security_desc(pSD);
1064     return NULL;
1065   }
1066 
1067   // add the access control entries
1068   if (!add_allow_aces(pSD, aces, count)) {
1069     free_security_desc(pSD);
1070     return NULL;
1071   }
1072 
1073   // allocate and initialize the security attributes structure and
1074   // return it to the caller.
1075   //
1076   LPSECURITY_ATTRIBUTES lpSA =
1077       NEW_C_HEAP_OBJ(SECURITY_ATTRIBUTES, mtInternal);
1078   lpSA->nLength = sizeof(SECURITY_ATTRIBUTES);
1079   lpSA->lpSecurityDescriptor = pSD;
1080   lpSA->bInheritHandle = FALSE;
1081 
1082   return(lpSA);
1083 }
1084 
1085 // method to create a security attributes structure with a restrictive
1086 // access control list that creates a set access rights for the user/owner
1087 // of the securable object and a separate set access rights for everyone else.
1088 // also provides for full access rights for the administrator group.
1089 //
1090 // the caller must free the resources associated with the security
1091 // attributes structure created by this method by calling the
1092 // free_security_attr() method.
1093 //
1094 
1095 static LPSECURITY_ATTRIBUTES make_user_everybody_admin_security_attr(
1096                                 DWORD umask, DWORD emask, DWORD amask) {
1097 
1098   ace_data_t aces[3];
1099 
1100   // initialize the user ace data
1101   aces[0].pSid = get_user_sid(GetCurrentProcess());
1102   aces[0].mask = umask;
1103 
1104   if (aces[0].pSid == 0)
1105     return NULL;
1106 
1107   // get the well known SID for BUILTIN\Administrators
1108   PSID administratorsSid = NULL;
1109   SID_IDENTIFIER_AUTHORITY SIDAuthAdministrators = SECURITY_NT_AUTHORITY;
1110 
1111   if (!AllocateAndInitializeSid( &SIDAuthAdministrators, 2,
1112            SECURITY_BUILTIN_DOMAIN_RID,
1113            DOMAIN_ALIAS_RID_ADMINS,
1114            0, 0, 0, 0, 0, 0, &administratorsSid)) {
1115 
1116     if (PrintMiscellaneous && Verbose) {
1117       warning("AllocateAndInitializeSid failure: "
1118               "lasterror = %d \n", GetLastError());
1119     }
1120     return NULL;
1121   }
1122 
1123   // initialize the ace data for administrator group
1124   aces[1].pSid = administratorsSid;
1125   aces[1].mask = amask;
1126 
1127   // get the well known SID for the universal Everybody
1128   PSID everybodySid = NULL;
1129   SID_IDENTIFIER_AUTHORITY SIDAuthEverybody = SECURITY_WORLD_SID_AUTHORITY;
1130 
1131   if (!AllocateAndInitializeSid( &SIDAuthEverybody, 1, SECURITY_WORLD_RID,
1132            0, 0, 0, 0, 0, 0, 0, &everybodySid)) {
1133 
1134     if (PrintMiscellaneous && Verbose) {
1135       warning("AllocateAndInitializeSid failure: "
1136               "lasterror = %d \n", GetLastError());
1137     }
1138     return NULL;
1139   }
1140 
1141   // initialize the ace data for everybody else.
1142   aces[2].pSid = everybodySid;
1143   aces[2].mask = emask;
1144 
1145   // create a security attributes structure with access control
1146   // entries as initialized above.
1147   LPSECURITY_ATTRIBUTES lpSA = make_security_attr(aces, 3);
1148   FREE_C_HEAP_ARRAY(char, aces[0].pSid);
1149   FreeSid(everybodySid);
1150   FreeSid(administratorsSid);
1151   return(lpSA);
1152 }
1153 
1154 
1155 // method to create the security attributes structure for restricting
1156 // access to the user temporary directory.
1157 //
1158 // the caller must free the resources associated with the security
1159 // attributes structure created by this method by calling the
1160 // free_security_attr() method.
1161 //
1162 static LPSECURITY_ATTRIBUTES make_tmpdir_security_attr() {
1163 
1164   // create full access rights for the user/owner of the directory
1165   // and read-only access rights for everybody else. This is
1166   // effectively equivalent to UNIX 755 permissions on a directory.
1167   //
1168   DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_ALL_ACCESS;
1169   DWORD emask = GENERIC_READ | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1170   DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1171 
1172   return make_user_everybody_admin_security_attr(umask, emask, amask);
1173 }
1174 
1175 // method to create the security attributes structure for restricting
1176 // access to the shared memory backing store file.
1177 //
1178 // the caller must free the resources associated with the security
1179 // attributes structure created by this method by calling the
1180 // free_security_attr() method.
1181 //
1182 static LPSECURITY_ATTRIBUTES make_file_security_attr() {
1183 
1184   // create extensive access rights for the user/owner of the file
1185   // and attribute read-only access rights for everybody else. This
1186   // is effectively equivalent to UNIX 600 permissions on a file.
1187   //
1188   DWORD umask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1189   DWORD emask = STANDARD_RIGHTS_READ | FILE_READ_ATTRIBUTES |
1190                  FILE_READ_EA | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1191   DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1192 
1193   return make_user_everybody_admin_security_attr(umask, emask, amask);
1194 }
1195 
1196 // method to create the security attributes structure for restricting
1197 // access to the name shared memory file mapping object.
1198 //
1199 // the caller must free the resources associated with the security
1200 // attributes structure created by this method by calling the
1201 // free_security_attr() method.
1202 //
1203 static LPSECURITY_ATTRIBUTES make_smo_security_attr() {
1204 
1205   // create extensive access rights for the user/owner of the shared
1206   // memory object and attribute read-only access rights for everybody
1207   // else. This is effectively equivalent to UNIX 600 permissions on
1208   // on the shared memory object.
1209   //
1210   DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_MAP_ALL_ACCESS;
1211   DWORD emask = STANDARD_RIGHTS_READ; // attributes only
1212   DWORD amask = STANDARD_RIGHTS_ALL | FILE_MAP_ALL_ACCESS;
1213 
1214   return make_user_everybody_admin_security_attr(umask, emask, amask);
1215 }
1216 
1217 // make the user specific temporary directory
1218 //
1219 static bool make_user_tmp_dir(const char* dirname) {
1220 
1221 
1222   LPSECURITY_ATTRIBUTES pDirSA = make_tmpdir_security_attr();
1223   if (pDirSA == NULL) {
1224     return false;
1225   }
1226 
1227 
1228   // create the directory with the given security attributes
1229   if (!CreateDirectory(dirname, pDirSA)) {
1230     DWORD lasterror = GetLastError();
1231     if (lasterror == ERROR_ALREADY_EXISTS) {
1232       // The directory already exists and was probably created by another
1233       // JVM instance. However, this could also be the result of a
1234       // deliberate symlink. Verify that the existing directory is safe.
1235       //
1236       if (!is_directory_secure(dirname)) {
1237         // directory is not secure
1238         if (PrintMiscellaneous && Verbose) {
1239           warning("%s directory is insecure\n", dirname);
1240         }
1241         return false;
1242       }
1243       // The administrator should be able to delete this directory.
1244       // But the directory created by previous version of JVM may not
1245       // have permission for administrators to delete this directory.
1246       // So add full permission to the administrator. Also setting new
1247       // DACLs might fix the corrupted the DACLs.
1248       SECURITY_INFORMATION secInfo = DACL_SECURITY_INFORMATION;
1249       if (!SetFileSecurity(dirname, secInfo, pDirSA->lpSecurityDescriptor)) {
1250         if (PrintMiscellaneous && Verbose) {
1251           lasterror = GetLastError();
1252           warning("SetFileSecurity failed for %s directory.  lasterror %d \n",
1253                                                         dirname, lasterror);
1254         }
1255       }
1256     }
1257     else {
1258       if (PrintMiscellaneous && Verbose) {
1259         warning("CreateDirectory failed: %d\n", GetLastError());
1260       }
1261       return false;
1262     }
1263   }
1264 
1265   // free the security attributes structure
1266   free_security_attr(pDirSA);
1267 
1268   return true;
1269 }
1270 
1271 // create the shared memory resources
1272 //
1273 // This function creates the shared memory resources. This includes
1274 // the backing store file and the file mapping shared memory object.
1275 //
1276 static HANDLE create_sharedmem_resources(const char* dirname, const char* filename, const char* objectname, size_t size) {
1277 
1278   HANDLE fh = INVALID_HANDLE_VALUE;
1279   HANDLE fmh = NULL;
1280 
1281 
1282   // create the security attributes for the backing store file
1283   LPSECURITY_ATTRIBUTES lpFileSA = make_file_security_attr();
1284   if (lpFileSA == NULL) {
1285     return NULL;
1286   }
1287 
1288   // create the security attributes for the shared memory object
1289   LPSECURITY_ATTRIBUTES lpSmoSA = make_smo_security_attr();
1290   if (lpSmoSA == NULL) {
1291     free_security_attr(lpFileSA);
1292     return NULL;
1293   }
1294 
1295   // create the user temporary directory
1296   if (!make_user_tmp_dir(dirname)) {
1297     // could not make/find the directory or the found directory
1298     // was not secure
1299     return NULL;
1300   }
1301 
1302   // Create the file - the FILE_FLAG_DELETE_ON_CLOSE flag allows the
1303   // file to be deleted by the last process that closes its handle to
1304   // the file. This is important as the apis do not allow a terminating
1305   // JVM being monitored by another process to remove the file name.
1306   //
1307   fh = CreateFile(
1308              filename,                          /* LPCTSTR file name */
1309 
1310              GENERIC_READ|GENERIC_WRITE,        /* DWORD desired access */
1311              FILE_SHARE_DELETE|FILE_SHARE_READ, /* DWORD share mode, future READONLY
1312                                                  * open operations allowed
1313                                                  */
1314              lpFileSA,                          /* LPSECURITY security attributes */
1315              CREATE_ALWAYS,                     /* DWORD creation disposition
1316                                                  * create file, if it already
1317                                                  * exists, overwrite it.
1318                                                  */
1319              FILE_FLAG_DELETE_ON_CLOSE,         /* DWORD flags and attributes */
1320 
1321              NULL);                             /* HANDLE template file access */
1322 
1323   free_security_attr(lpFileSA);
1324 
1325   if (fh == INVALID_HANDLE_VALUE) {
1326     DWORD lasterror = GetLastError();
1327     if (PrintMiscellaneous && Verbose) {
1328       warning("could not create file %s: %d\n", filename, lasterror);
1329     }
1330     return NULL;
1331   }
1332 
1333   // try to create the file mapping
1334   fmh = create_file_mapping(objectname, fh, lpSmoSA, size);
1335 
1336   free_security_attr(lpSmoSA);
1337 
1338   if (fmh == NULL) {
1339     // closing the file handle here will decrement the reference count
1340     // on the file. When all processes accessing the file close their
1341     // handle to it, the reference count will decrement to 0 and the
1342     // OS will delete the file. These semantics are requested by the
1343     // FILE_FLAG_DELETE_ON_CLOSE flag in CreateFile call above.
1344     CloseHandle(fh);
1345     fh = NULL;
1346     return NULL;
1347   } else {
1348     // We created the file mapping, but rarely the size of the
1349     // backing store file is reported as zero (0) which can cause
1350     // failures when trying to use the hsperfdata file.
1351     struct stat statbuf;
1352     int ret_code = ::stat(filename, &statbuf);
1353     if (ret_code == OS_ERR) {
1354       if (PrintMiscellaneous && Verbose) {
1355         warning("Could not get status information from file %s: %s\n",
1356             filename, os::strerror(errno));
1357       }
1358       CloseHandle(fmh);
1359       CloseHandle(fh);
1360       fh = NULL;
1361       fmh = NULL;
1362       return NULL;
1363     }
1364 
1365     // We could always call FlushFileBuffers() but the Microsoft
1366     // docs indicate that it is considered expensive so we only
1367     // call it when we observe the size as zero (0).
1368     if (statbuf.st_size == 0 && FlushFileBuffers(fh) != TRUE) {
1369       DWORD lasterror = GetLastError();
1370       if (PrintMiscellaneous && Verbose) {
1371         warning("could not flush file %s: %d\n", filename, lasterror);
1372       }
1373       CloseHandle(fmh);
1374       CloseHandle(fh);
1375       fh = NULL;
1376       fmh = NULL;
1377       return NULL;
1378     }
1379   }
1380 
1381   // the file has been successfully created and the file mapping
1382   // object has been created.
1383   sharedmem_fileHandle = fh;
1384   sharedmem_fileName = os::strdup(filename);
1385 
1386   return fmh;
1387 }
1388 
1389 // open the shared memory object for the given vmid.
1390 //
1391 static HANDLE open_sharedmem_object(const char* objectname, DWORD ofm_access, TRAPS) {
1392 
1393   HANDLE fmh;
1394 
1395   // open the file mapping with the requested mode
1396   fmh = OpenFileMapping(
1397                ofm_access,       /* DWORD access mode */
1398                FALSE,            /* BOOL inherit flag - Do not allow inherit */
1399                objectname);      /* name for object */
1400 
1401   if (fmh == NULL) {
1402     DWORD lasterror = GetLastError();
1403     if (PrintMiscellaneous && Verbose) {
1404       warning("OpenFileMapping failed for shared memory object %s:"
1405               " lasterror = %d\n", objectname, lasterror);
1406     }
1407     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),
1408                err_msg("Could not open PerfMemory, error %d", lasterror),
1409                INVALID_HANDLE_VALUE);
1410   }
1411 
1412   return fmh;;
1413 }
1414 
1415 // create a named shared memory region
1416 //
1417 // On Win32, a named shared memory object has a name space that
1418 // is independent of the file system name space. Shared memory object,
1419 // or more precisely, file mapping objects, provide no mechanism to
1420 // inquire the size of the memory region. There is also no api to
1421 // enumerate the memory regions for various processes.
1422 //
1423 // This implementation utilizes the shared memory name space in parallel
1424 // with the file system name space. This allows us to determine the
1425 // size of the shared memory region from the size of the file and it
1426 // allows us to provide a common, file system based name space for
1427 // shared memory across platforms.
1428 //
1429 static char* mapping_create_shared(size_t size) {
1430 
1431   void *mapAddress;
1432   int vmid = os::current_process_id();
1433 
1434   // get the name of the user associated with this process
1435   char* user = get_user_name();
1436 
1437   if (user == NULL) {
1438     return NULL;
1439   }
1440 
1441   // construct the name of the user specific temporary directory
1442   char* dirname = get_user_tmp_dir(user);
1443 
1444   // check that the file system is secure - i.e. it supports ACLs.
1445   if (!is_filesystem_secure(dirname)) {
1446     FREE_C_HEAP_ARRAY(char, dirname);
1447     FREE_C_HEAP_ARRAY(char, user);
1448     return NULL;
1449   }
1450 
1451   // create the names of the backing store files and for the
1452   // share memory object.
1453   //
1454   char* filename = get_sharedmem_filename(dirname, vmid);
1455   char* objectname = get_sharedmem_objectname(user, vmid);
1456 
1457   // cleanup any stale shared memory resources
1458   cleanup_sharedmem_resources(dirname);
1459 
1460   assert(((size != 0) && (size % os::vm_page_size() == 0)),
1461          "unexpected PerfMemry region size");
1462 
1463   FREE_C_HEAP_ARRAY(char, user);
1464 
1465   // create the shared memory resources
1466   sharedmem_fileMapHandle =
1467                create_sharedmem_resources(dirname, filename, objectname, size);
1468 
1469   FREE_C_HEAP_ARRAY(char, filename);
1470   FREE_C_HEAP_ARRAY(char, objectname);
1471   FREE_C_HEAP_ARRAY(char, dirname);
1472 
1473   if (sharedmem_fileMapHandle == NULL) {
1474     return NULL;
1475   }
1476 
1477   // map the file into the address space
1478   mapAddress = MapViewOfFile(
1479                    sharedmem_fileMapHandle, /* HANDLE = file mapping object */
1480                    FILE_MAP_ALL_ACCESS,     /* DWORD access flags */
1481                    0,                       /* DWORD High word of offset */
1482                    0,                       /* DWORD Low word of offset */
1483                    (DWORD)size);            /* DWORD Number of bytes to map */
1484 
1485   if (mapAddress == NULL) {
1486     if (PrintMiscellaneous && Verbose) {
1487       warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1488     }
1489     CloseHandle(sharedmem_fileMapHandle);
1490     sharedmem_fileMapHandle = NULL;
1491     return NULL;
1492   }
1493 
1494   // clear the shared memory region
1495   (void)memset(mapAddress, '\0', size);
1496 
1497   // it does not go through os api, the operation has to record from here
1498   MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress,
1499     size, CURRENT_PC, mtInternal);
1500 
1501   return (char*) mapAddress;
1502 }
1503 
1504 // this method deletes the file mapping object.
1505 //
1506 static void delete_file_mapping(char* addr, size_t size) {
1507 
1508   // cleanup the persistent shared memory resources. since DestroyJavaVM does
1509   // not support unloading of the JVM, unmapping of the memory resource is not
1510   // performed. The memory will be reclaimed by the OS upon termination of all
1511   // processes mapping the resource. The file mapping handle and the file
1512   // handle are closed here to expedite the remove of the file by the OS. The
1513   // file is not removed directly because it was created with
1514   // FILE_FLAG_DELETE_ON_CLOSE semantics and any attempt to remove it would
1515   // be unsuccessful.
1516 
1517   // close the fileMapHandle. the file mapping will still be retained
1518   // by the OS as long as any other JVM processes has an open file mapping
1519   // handle or a mapped view of the file.
1520   //
1521   if (sharedmem_fileMapHandle != NULL) {
1522     CloseHandle(sharedmem_fileMapHandle);
1523     sharedmem_fileMapHandle = NULL;
1524   }
1525 
1526   // close the file handle. This will decrement the reference count on the
1527   // backing store file. When the reference count decrements to 0, the OS
1528   // will delete the file. These semantics apply because the file was
1529   // created with the FILE_FLAG_DELETE_ON_CLOSE flag.
1530   //
1531   if (sharedmem_fileHandle != INVALID_HANDLE_VALUE) {
1532     CloseHandle(sharedmem_fileHandle);
1533     sharedmem_fileHandle = INVALID_HANDLE_VALUE;
1534   }
1535 }
1536 
1537 // this method determines the size of the shared memory file
1538 //
1539 static size_t sharedmem_filesize(const char* filename, TRAPS) {
1540 
1541   struct stat statbuf;
1542 
1543   // get the file size
1544   //
1545   // on win95/98/me, _stat returns a file size of 0 bytes, but on
1546   // winnt/2k the appropriate file size is returned. support for
1547   // the sharable aspects of performance counters was abandonded
1548   // on the non-nt win32 platforms due to this and other api
1549   // inconsistencies
1550   //
1551   if (::stat(filename, &statbuf) == OS_ERR) {
1552     if (PrintMiscellaneous && Verbose) {
1553       warning("stat %s failed: %s\n", filename, os::strerror(errno));
1554     }
1555     THROW_MSG_0(vmSymbols::java_io_IOException(),
1556                 "Could not determine PerfMemory size");
1557   }
1558 
1559   if ((statbuf.st_size == 0) || (statbuf.st_size % os::vm_page_size() != 0)) {
1560     if (PrintMiscellaneous && Verbose) {
1561       warning("unexpected file size: size = " SIZE_FORMAT "\n",
1562               statbuf.st_size);
1563     }
1564     THROW_MSG_0(vmSymbols::java_io_IOException(),
1565                 "Invalid PerfMemory size");
1566   }
1567 
1568   return statbuf.st_size;
1569 }
1570 
1571 // this method opens a file mapping object and maps the object
1572 // into the address space of the process
1573 //
1574 static void open_file_mapping(const char* user, int vmid,
1575                               PerfMemory::PerfMemoryMode mode,
1576                               char** addrp, size_t* sizep, TRAPS) {
1577 
1578   ResourceMark rm;
1579 
1580   void *mapAddress = 0;
1581   size_t size = 0;
1582   HANDLE fmh;
1583   DWORD ofm_access;
1584   DWORD mv_access;
1585   const char* luser = NULL;
1586 
1587   if (mode == PerfMemory::PERF_MODE_RO) {
1588     ofm_access = FILE_MAP_READ;
1589     mv_access = FILE_MAP_READ;
1590   }
1591   else if (mode == PerfMemory::PERF_MODE_RW) {
1592 #ifdef LATER
1593     ofm_access = FILE_MAP_READ | FILE_MAP_WRITE;
1594     mv_access = FILE_MAP_READ | FILE_MAP_WRITE;
1595 #else
1596     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1597               "Unsupported access mode");
1598 #endif
1599   }
1600   else {
1601     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1602               "Illegal access mode");
1603   }
1604 
1605   // if a user name wasn't specified, then find the user name for
1606   // the owner of the target vm.
1607   if (user == NULL || strlen(user) == 0) {
1608     luser = get_user_name(vmid);
1609   }
1610   else {
1611     luser = user;
1612   }
1613 
1614   if (luser == NULL) {
1615     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1616               "Could not map vmid to user name");
1617   }
1618 
1619   // get the names for the resources for the target vm
1620   char* dirname = get_user_tmp_dir(luser);
1621 
1622   // since we don't follow symbolic links when creating the backing
1623   // store file, we also don't following them when attaching
1624   //
1625   if (!is_directory_secure(dirname)) {
1626     FREE_C_HEAP_ARRAY(char, dirname);
1627     if (luser != user) FREE_C_HEAP_ARRAY(char, luser);
1628     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1629               "Process not found");
1630   }
1631 
1632   char* filename = get_sharedmem_filename(dirname, vmid);
1633   char* objectname = get_sharedmem_objectname(luser, vmid);
1634 
1635   // copy heap memory to resource memory. the objectname and
1636   // filename are passed to methods that may throw exceptions.
1637   // using resource arrays for these names prevents the leaks
1638   // that would otherwise occur.
1639   //
1640   char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
1641   char* robjectname = NEW_RESOURCE_ARRAY(char, strlen(objectname) + 1);
1642   strcpy(rfilename, filename);
1643   strcpy(robjectname, objectname);
1644 
1645   // free the c heap resources that are no longer needed
1646   if (luser != user) FREE_C_HEAP_ARRAY(char, luser);
1647   FREE_C_HEAP_ARRAY(char, dirname);
1648   FREE_C_HEAP_ARRAY(char, filename);
1649   FREE_C_HEAP_ARRAY(char, objectname);
1650 
1651   if (*sizep == 0) {
1652     size = sharedmem_filesize(rfilename, CHECK);
1653   } else {
1654     size = *sizep;
1655   }
1656 
1657   assert(size > 0, "unexpected size <= 0");
1658 
1659   // Open the file mapping object with the given name
1660   fmh = open_sharedmem_object(robjectname, ofm_access, CHECK);
1661 
1662   assert(fmh != INVALID_HANDLE_VALUE, "unexpected handle value");
1663 
1664   // map the entire file into the address space
1665   mapAddress = MapViewOfFile(
1666                  fmh,             /* HANDLE Handle of file mapping object */
1667                  mv_access,       /* DWORD access flags */
1668                  0,               /* DWORD High word of offset */
1669                  0,               /* DWORD Low word of offset */
1670                  size);           /* DWORD Number of bytes to map */
1671 
1672   if (mapAddress == NULL) {
1673     if (PrintMiscellaneous && Verbose) {
1674       warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1675     }
1676     CloseHandle(fmh);
1677     THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
1678               "Could not map PerfMemory");
1679   }
1680 
1681   // it does not go through os api, the operation has to record from here
1682   MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress, size,
1683     CURRENT_PC, mtInternal);
1684 
1685 
1686   *addrp = (char*)mapAddress;
1687   *sizep = size;
1688 
1689   // File mapping object can be closed at this time without
1690   // invalidating the mapped view of the file
1691   CloseHandle(fmh);
1692 
1693   log_debug(perf, memops)("mapped " SIZE_FORMAT " bytes for vmid %d at "
1694                           INTPTR_FORMAT, size, vmid, mapAddress);
1695 }
1696 
1697 // this method unmaps the the mapped view of the the
1698 // file mapping object.
1699 //
1700 static void remove_file_mapping(char* addr) {
1701 
1702   // the file mapping object was closed in open_file_mapping()
1703   // after the file map view was created. We only need to
1704   // unmap the file view here.
1705   UnmapViewOfFile(addr);
1706 }
1707 
1708 // create the PerfData memory region in shared memory.
1709 static char* create_shared_memory(size_t size) {
1710 
1711   return mapping_create_shared(size);
1712 }
1713 
1714 // release a named, shared memory region
1715 //
1716 void delete_shared_memory(char* addr, size_t size) {
1717 
1718   delete_file_mapping(addr, size);
1719 }
1720 
1721 
1722 
1723 
1724 // create the PerfData memory region
1725 //
1726 // This method creates the memory region used to store performance
1727 // data for the JVM. The memory may be created in standard or
1728 // shared memory.
1729 //
1730 void PerfMemory::create_memory_region(size_t size) {
1731 
1732   if (PerfDisableSharedMem) {
1733     // do not share the memory for the performance data.
1734     PerfDisableSharedMem = true;
1735     _start = create_standard_memory(size);
1736   }
1737   else {
1738     _start = create_shared_memory(size);
1739     if (_start == NULL) {
1740 
1741       // creation of the shared memory region failed, attempt
1742       // to create a contiguous, non-shared memory region instead.
1743       //
1744       if (PrintMiscellaneous && Verbose) {
1745         warning("Reverting to non-shared PerfMemory region.\n");
1746       }
1747       PerfDisableSharedMem = true;
1748       _start = create_standard_memory(size);
1749     }
1750   }
1751 
1752   if (_start != NULL) _capacity = size;
1753 
1754 }
1755 
1756 // delete the PerfData memory region
1757 //
1758 // This method deletes the memory region used to store performance
1759 // data for the JVM. The memory region indicated by the <address, size>
1760 // tuple will be inaccessible after a call to this method.
1761 //
1762 void PerfMemory::delete_memory_region() {
1763 
1764   assert((start() != NULL && capacity() > 0), "verify proper state");
1765 
1766   // If user specifies PerfDataSaveFile, it will save the performance data
1767   // to the specified file name no matter whether PerfDataSaveToFile is specified
1768   // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
1769   // -XX:+PerfDataSaveToFile.
1770   if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
1771     save_memory_to_file(start(), capacity());
1772   }
1773 
1774   if (PerfDisableSharedMem) {
1775     delete_standard_memory(start(), capacity());
1776   }
1777   else {
1778     delete_shared_memory(start(), capacity());
1779   }
1780 }
1781 
1782 // attach to the PerfData memory region for another JVM
1783 //
1784 // This method returns an <address, size> tuple that points to
1785 // a memory buffer that is kept reasonably synchronized with
1786 // the PerfData memory region for the indicated JVM. This
1787 // buffer may be kept in synchronization via shared memory
1788 // or some other mechanism that keeps the buffer updated.
1789 //
1790 // If the JVM chooses not to support the attachability feature,
1791 // this method should throw an UnsupportedOperation exception.
1792 //
1793 // This implementation utilizes named shared memory to map
1794 // the indicated process's PerfData memory region into this JVMs
1795 // address space.
1796 //
1797 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode,
1798                         char** addrp, size_t* sizep, TRAPS) {
1799 
1800   if (vmid == 0 || vmid == os::current_process_id()) {
1801      *addrp = start();
1802      *sizep = capacity();
1803      return;
1804   }
1805 
1806   open_file_mapping(user, vmid, mode, addrp, sizep, CHECK);
1807 }
1808 
1809 // detach from the PerfData memory region of another JVM
1810 //
1811 // This method detaches the PerfData memory region of another
1812 // JVM, specified as an <address, size> tuple of a buffer
1813 // in this process's address space. This method may perform
1814 // arbitrary actions to accomplish the detachment. The memory
1815 // region specified by <address, size> will be inaccessible after
1816 // a call to this method.
1817 //
1818 // If the JVM chooses not to support the attachability feature,
1819 // this method should throw an UnsupportedOperation exception.
1820 //
1821 // This implementation utilizes named shared memory to detach
1822 // the indicated process's PerfData memory region from this
1823 // process's address space.
1824 //
1825 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
1826 
1827   assert(addr != 0, "address sanity check");
1828   assert(bytes > 0, "capacity sanity check");
1829 
1830   if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
1831     // prevent accidental detachment of this process's PerfMemory region
1832     return;
1833   }
1834 
1835   if (MemTracker::tracking_level() > NMT_minimal) {
1836     // it does not go through os api, the operation has to record from here
1837     Tracker tkr(Tracker::release);
1838     remove_file_mapping(addr);
1839     tkr.record((address)addr, bytes);
1840   } else {
1841     remove_file_mapping(addr);
1842   }
1843 }