1 /*
   2  * Copyright (c) 2001, 2010, 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 "memory/allocation.inline.hpp"
  28 #include "memory/resourceArea.hpp"
  29 #include "oops/oop.inline.hpp"
  30 #include "os_windows.inline.hpp"
  31 #include "runtime/handles.inline.hpp"
  32 #include "runtime/perfMemory.hpp"
  33 #include "utilities/exceptions.hpp"
  34 
  35 #include <windows.h>
  36 #include <sys/types.h>
  37 #include <sys/stat.h>
  38 #include <errno.h>
  39 #include <lmcons.h>
  40 
  41 typedef BOOL (WINAPI *SetSecurityDescriptorControlFnPtr)(
  42    IN PSECURITY_DESCRIPTOR pSecurityDescriptor,
  43    IN SECURITY_DESCRIPTOR_CONTROL ControlBitsOfInterest,
  44    IN SECURITY_DESCRIPTOR_CONTROL ControlBitsToSet);
  45 
  46 // Standard Memory Implementation Details
  47 
  48 // create the PerfData memory region in standard memory.
  49 //
  50 static char* create_standard_memory(size_t size) {
  51 
  52   // allocate an aligned chuck of memory
  53   char* mapAddress = os::reserve_memory(size);
  54 
  55   if (mapAddress == NULL) {
  56     return NULL;
  57   }
  58 
  59   // commit memory
  60   if (!os::commit_memory(mapAddress, size)) {
  61     if (PrintMiscellaneous && Verbose) {
  62       warning("Could not commit PerfData memory\n");
  63     }
  64     os::release_memory(mapAddress, size);
  65     return NULL;
  66   }
  67 
  68   return mapAddress;
  69 }
  70 
  71 // delete the PerfData memory region
  72 //
  73 static void delete_standard_memory(char* addr, size_t size) {
  74 
  75   // there are no persistent external resources to cleanup for standard
  76   // memory. since DestroyJavaVM does not support unloading of the JVM,
  77   // cleanup of the memory resource is not performed. The memory will be
  78   // reclaimed by the OS upon termination of the process.
  79   //
  80   return;
  81 
  82 }
  83 
  84 // save the specified memory region to the given file
  85 //
  86 static void save_memory_to_file(char* addr, size_t size) {
  87 
  88   const char* destfile = PerfMemory::get_perfdata_file_path();
  89   assert(destfile[0] != '\0', "invalid Perfdata file path");
  90 
  91   int fd = ::_open(destfile, _O_BINARY|_O_CREAT|_O_WRONLY|_O_TRUNC,
  92                    _S_IREAD|_S_IWRITE);
  93 
  94   if (fd == OS_ERR) {
  95     if (PrintMiscellaneous && Verbose) {
  96       warning("Could not create Perfdata save file: %s: %s\n",
  97               destfile, strerror(errno));
  98     }
  99   } else {
 100     for (size_t remaining = size; remaining > 0;) {
 101 
 102       int nbytes = ::_write(fd, addr, (unsigned int)remaining);
 103       if (nbytes == OS_ERR) {
 104         if (PrintMiscellaneous && Verbose) {
 105           warning("Could not write Perfdata save file: %s: %s\n",
 106                   destfile, strerror(errno));
 107         }
 108         break;
 109       }
 110 
 111       remaining -= (size_t)nbytes;
 112       addr += nbytes;
 113     }
 114 
 115     int result = ::_close(fd);
 116     if (PrintMiscellaneous && Verbose) {
 117       if (result == OS_ERR) {
 118         warning("Could not close %s: %s\n", destfile, strerror(errno));
 119       }
 120     }
 121   }
 122 
 123   FREE_C_HEAP_ARRAY(char, destfile);
 124 }
 125 
 126 // Shared Memory Implementation Details
 127 
 128 // Note: the win32 shared memory implementation uses two objects to represent
 129 // the shared memory: a windows kernel based file mapping object and a backing
 130 // store file. On windows, the name space for shared memory is a kernel
 131 // based name space that is disjoint from other win32 name spaces. Since Java
 132 // is unaware of this name space, a parallel file system based name space is
 133 // maintained, which provides a common file system based shared memory name
 134 // space across the supported platforms and one that Java apps can deal with
 135 // through simple file apis.
 136 //
 137 // For performance and resource cleanup reasons, it is recommended that the
 138 // user specific directory and the backing store file be stored in either a
 139 // RAM based file system or a local disk based file system. Network based
 140 // file systems are not recommended for performance reasons. In addition,
 141 // use of SMB network based file systems may result in unsuccesful cleanup
 142 // of the disk based resource on exit of the VM. The Windows TMP and TEMP
 143 // environement variables, as used by the GetTempPath() Win32 API (see
 144 // os::get_temp_directory() in os_win32.cpp), control the location of the
 145 // user specific directory and the shared memory backing store file.
 146 
 147 static HANDLE sharedmem_fileMapHandle = NULL;
 148 static HANDLE sharedmem_fileHandle = INVALID_HANDLE_VALUE;
 149 static char*  sharedmem_fileName = NULL;
 150 
 151 // return the user specific temporary directory name.
 152 //
 153 // the caller is expected to free the allocated memory.
 154 //
 155 static char* get_user_tmp_dir(const char* user) {
 156 
 157   const char* tmpdir = os::get_temp_directory();
 158   const char* perfdir = PERFDATA_NAME;
 159   size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3;
 160   char* dirname = NEW_C_HEAP_ARRAY(char, nbytes);
 161 
 162   // construct the path name to user specific tmp directory
 163   _snprintf(dirname, nbytes, "%s\\%s_%s", tmpdir, perfdir, user);
 164 
 165   return dirname;
 166 }
 167 
 168 // convert the given file name into a process id. if the file
 169 // does not meet the file naming constraints, return 0.
 170 //
 171 static int filename_to_pid(const char* filename) {
 172 
 173   // a filename that doesn't begin with a digit is not a
 174   // candidate for conversion.
 175   //
 176   if (!isdigit(*filename)) {
 177     return 0;
 178   }
 179 
 180   // check if file name can be converted to an integer without
 181   // any leftover characters.
 182   //
 183   char* remainder = NULL;
 184   errno = 0;
 185   int pid = (int)strtol(filename, &remainder, 10);
 186 
 187   if (errno != 0) {
 188     return 0;
 189   }
 190 
 191   // check for left over characters. If any, then the filename is
 192   // not a candidate for conversion.
 193   //
 194   if (remainder != NULL && *remainder != '\0') {
 195     return 0;
 196   }
 197 
 198   // successful conversion, return the pid
 199   return pid;
 200 }
 201 
 202 // check if the given path is considered a secure directory for
 203 // the backing store files. Returns true if the directory exists
 204 // and is considered a secure location. Returns false if the path
 205 // is a symbolic link or if an error occurred.
 206 //
 207 static bool is_directory_secure(const char* path) {
 208 
 209   DWORD fa;
 210 
 211   fa = GetFileAttributes(path);
 212   if (fa == 0xFFFFFFFF) {
 213     DWORD lasterror = GetLastError();
 214     if (lasterror == ERROR_FILE_NOT_FOUND) {
 215       return false;
 216     }
 217     else {
 218       // unexpected error, declare the path insecure
 219       if (PrintMiscellaneous && Verbose) {
 220         warning("could not get attributes for file %s: ",
 221                 " lasterror = %d\n", path, lasterror);
 222       }
 223       return false;
 224     }
 225   }
 226 
 227   if (fa & FILE_ATTRIBUTE_REPARSE_POINT) {
 228     // we don't accept any redirection for the user specific directory
 229     // so declare the path insecure. This may be too conservative,
 230     // as some types of reparse points might be acceptable, but it
 231     // is probably more secure to avoid these conditions.
 232     //
 233     if (PrintMiscellaneous && Verbose) {
 234       warning("%s is a reparse point\n", path);
 235     }
 236     return false;
 237   }
 238 
 239   if (fa & FILE_ATTRIBUTE_DIRECTORY) {
 240     // this is the expected case. Since windows supports symbolic
 241     // links to directories only, not to files, there is no need
 242     // to check for open write permissions on the directory. If the
 243     // directory has open write permissions, any files deposited that
 244     // are not expected will be removed by the cleanup code.
 245     //
 246     return true;
 247   }
 248   else {
 249     // this is either a regular file or some other type of file,
 250     // any of which are unexpected and therefore insecure.
 251     //
 252     if (PrintMiscellaneous && Verbose) {
 253       warning("%s is not a directory, file attributes = "
 254               INTPTR_FORMAT "\n", path, fa);
 255     }
 256     return false;
 257   }
 258 }
 259 
 260 // return the user name for the owner of this process
 261 //
 262 // the caller is expected to free the allocated memory.
 263 //
 264 static char* get_user_name() {
 265 
 266   /* get the user name. This code is adapted from code found in
 267    * the jdk in src/windows/native/java/lang/java_props_md.c
 268    * java_props_md.c  1.29 02/02/06. According to the original
 269    * source, the call to GetUserName is avoided because of a resulting
 270    * increase in footprint of 100K.
 271    */
 272   char* user = getenv("USERNAME");
 273   char buf[UNLEN+1];
 274   DWORD buflen = sizeof(buf);
 275   if (user == NULL || strlen(user) == 0) {
 276     if (GetUserName(buf, &buflen)) {
 277       user = buf;
 278     }
 279     else {
 280       return NULL;
 281     }
 282   }
 283 
 284   char* user_name = NEW_C_HEAP_ARRAY(char, strlen(user)+1);
 285   strcpy(user_name, user);
 286 
 287   return user_name;
 288 }
 289 
 290 // return the name of the user that owns the process identified by vmid.
 291 //
 292 // This method uses a slow directory search algorithm to find the backing
 293 // store file for the specified vmid and returns the user name, as determined
 294 // by the user name suffix of the hsperfdata_<username> directory name.
 295 //
 296 // the caller is expected to free the allocated memory.
 297 //
 298 static char* get_user_name_slow(int vmid) {
 299 
 300   // directory search
 301   char* oldest_user = NULL;
 302   time_t oldest_ctime = 0;
 303 
 304   const char* tmpdirname = os::get_temp_directory();
 305 
 306   DIR* tmpdirp = os::opendir(tmpdirname);
 307 
 308   if (tmpdirp == NULL) {
 309     return NULL;
 310   }
 311 
 312   // for each entry in the directory that matches the pattern hsperfdata_*,
 313   // open the directory and check if the file for the given vmid exists.
 314   // The file with the expected name and the latest creation date is used
 315   // to determine the user name for the process id.
 316   //
 317   struct dirent* dentry;
 318   char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname));
 319   errno = 0;
 320   while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) {
 321 
 322     // check if the directory entry is a hsperfdata file
 323     if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
 324       continue;
 325     }
 326 
 327     char* usrdir_name = NEW_C_HEAP_ARRAY(char,
 328                               strlen(tmpdirname) + strlen(dentry->d_name) + 2);
 329     strcpy(usrdir_name, tmpdirname);
 330     strcat(usrdir_name, "\\");
 331     strcat(usrdir_name, dentry->d_name);
 332 
 333     DIR* subdirp = os::opendir(usrdir_name);
 334 
 335     if (subdirp == NULL) {
 336       FREE_C_HEAP_ARRAY(char, usrdir_name);
 337       continue;
 338     }
 339 
 340     // Since we don't create the backing store files in directories
 341     // pointed to by symbolic links, we also don't follow them when
 342     // looking for the files. We check for a symbolic link after the
 343     // call to opendir in order to eliminate a small window where the
 344     // symlink can be exploited.
 345     //
 346     if (!is_directory_secure(usrdir_name)) {
 347       FREE_C_HEAP_ARRAY(char, usrdir_name);
 348       os::closedir(subdirp);
 349       continue;
 350     }
 351 
 352     struct dirent* udentry;
 353     char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name));
 354     errno = 0;
 355     while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
 356 
 357       if (filename_to_pid(udentry->d_name) == vmid) {
 358         struct stat statbuf;
 359 
 360         char* filename = NEW_C_HEAP_ARRAY(char,
 361                             strlen(usrdir_name) + strlen(udentry->d_name) + 2);
 362 
 363         strcpy(filename, usrdir_name);
 364         strcat(filename, "\\");
 365         strcat(filename, udentry->d_name);
 366 
 367         if (::stat(filename, &statbuf) == OS_ERR) {
 368            FREE_C_HEAP_ARRAY(char, filename);
 369            continue;
 370         }
 371 
 372         // skip over files that are not regular files.
 373         if ((statbuf.st_mode & S_IFMT) != S_IFREG) {
 374           FREE_C_HEAP_ARRAY(char, filename);
 375           continue;
 376         }
 377 
 378         // compare and save filename with latest creation time
 379         if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) {
 380 
 381           if (statbuf.st_ctime > oldest_ctime) {












 382             char* user = strchr(dentry->d_name, '_') + 1;
 383 
 384             if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user);
 385             oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1);
 386 
 387             strcpy(oldest_user, user);
 388             oldest_ctime = statbuf.st_ctime;
 389           }
 390         }
 391 
 392         FREE_C_HEAP_ARRAY(char, filename);
 393       }
 394     }
 395     os::closedir(subdirp);
 396     FREE_C_HEAP_ARRAY(char, udbuf);
 397     FREE_C_HEAP_ARRAY(char, usrdir_name);
 398   }
 399   os::closedir(tmpdirp);
 400   FREE_C_HEAP_ARRAY(char, tdbuf);
 401 
 402   return(oldest_user);
 403 }
 404 
 405 // return the name of the user that owns the process identified by vmid.
 406 //
 407 // note: this method should only be used via the Perf native methods.
 408 // There are various costs to this method and limiting its use to the
 409 // Perf native methods limits the impact to monitoring applications only.
 410 //
 411 static char* get_user_name(int vmid) {
 412 
 413   // A fast implementation is not provided at this time. It's possible
 414   // to provide a fast process id to user name mapping function using
 415   // the win32 apis, but the default ACL for the process object only
 416   // allows processes with the same owner SID to acquire the process
 417   // handle (via OpenProcess(PROCESS_QUERY_INFORMATION)). It's possible
 418   // to have the JVM change the ACL for the process object to allow arbitrary
 419   // users to access the process handle and the process security token.
 420   // The security ramifications need to be studied before providing this
 421   // mechanism.
 422   //
 423   return get_user_name_slow(vmid);
 424 }
 425 
 426 // return the name of the shared memory file mapping object for the
 427 // named shared memory region for the given user name and vmid.
 428 //
 429 // The file mapping object's name is not the file name. It is a name
 430 // in a separate name space.
 431 //
 432 // the caller is expected to free the allocated memory.
 433 //
 434 static char *get_sharedmem_objectname(const char* user, int vmid) {
 435 
 436   // construct file mapping object's name, add 3 for two '_' and a
 437   // null terminator.
 438   int nbytes = (int)strlen(PERFDATA_NAME) + (int)strlen(user) + 3;
 439 
 440   // the id is converted to an unsigned value here because win32 allows
 441   // negative process ids. However, OpenFileMapping API complains
 442   // about a name containing a '-' characters.
 443   //
 444   nbytes += UINT_CHARS;
 445   char* name = NEW_C_HEAP_ARRAY(char, nbytes);
 446   _snprintf(name, nbytes, "%s_%s_%u", PERFDATA_NAME, user, vmid);
 447 
 448   return name;
 449 }
 450 
 451 // return the file name of the backing store file for the named
 452 // shared memory region for the given user name and vmid.
 453 //
 454 // the caller is expected to free the allocated memory.
 455 //
 456 static char* get_sharedmem_filename(const char* dirname, int vmid) {
 457 
 458   // add 2 for the file separator and a null terminator.
 459   size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
 460 
 461   char* name = NEW_C_HEAP_ARRAY(char, nbytes);
 462   _snprintf(name, nbytes, "%s\\%d", dirname, vmid);
 463 
 464   return name;
 465 }
 466 
 467 // remove file
 468 //
 469 // this method removes the file with the given file name.
 470 //
 471 // Note: if the indicated file is on an SMB network file system, this
 472 // method may be unsuccessful in removing the file.
 473 //
 474 static void remove_file(const char* dirname, const char* filename) {
 475 
 476   size_t nbytes = strlen(dirname) + strlen(filename) + 2;
 477   char* path = NEW_C_HEAP_ARRAY(char, nbytes);
 478 
 479   strcpy(path, dirname);
 480   strcat(path, "\\");
 481   strcat(path, filename);
 482 
 483   if (::unlink(path) == OS_ERR) {
 484     if (PrintMiscellaneous && Verbose) {
 485       if (errno != ENOENT) {
 486         warning("Could not unlink shared memory backing"
 487                 " store file %s : %s\n", path, strerror(errno));
 488       }
 489     }
 490   }
 491 
 492   FREE_C_HEAP_ARRAY(char, path);
 493 }
 494 
 495 // returns true if the process represented by pid is alive, otherwise
 496 // returns false. the validity of the result is only accurate if the
 497 // target process is owned by the same principal that owns this process.
 498 // this method should not be used if to test the status of an otherwise
 499 // arbitrary process unless it is know that this process has the appropriate
 500 // privileges to guarantee a result valid.
 501 //
 502 static bool is_alive(int pid) {
 503 
 504   HANDLE ph = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid);
 505   if (ph == NULL) {
 506     // the process does not exist.
 507     if (PrintMiscellaneous && Verbose) {
 508       DWORD lastError = GetLastError();
 509       if (lastError != ERROR_INVALID_PARAMETER) {
 510         warning("OpenProcess failed: %d\n", GetLastError());
 511       }
 512     }
 513     return false;
 514   }
 515 
 516   DWORD exit_status;
 517   if (!GetExitCodeProcess(ph, &exit_status)) {
 518     if (PrintMiscellaneous && Verbose) {
 519       warning("GetExitCodeProcess failed: %d\n", GetLastError());
 520     }
 521     CloseHandle(ph);
 522     return false;
 523   }
 524 
 525   CloseHandle(ph);
 526   return (exit_status == STILL_ACTIVE) ? true : false;
 527 }
 528 
 529 // check if the file system is considered secure for the backing store files
 530 //
 531 static bool is_filesystem_secure(const char* path) {
 532 
 533   char root_path[MAX_PATH];
 534   char fs_type[MAX_PATH];
 535 
 536   if (PerfBypassFileSystemCheck) {
 537     if (PrintMiscellaneous && Verbose) {
 538       warning("bypassing file system criteria checks for %s\n", path);
 539     }
 540     return true;
 541   }
 542 
 543   char* first_colon = strchr((char *)path, ':');
 544   if (first_colon == NULL) {
 545     if (PrintMiscellaneous && Verbose) {
 546       warning("expected device specifier in path: %s\n", path);
 547     }
 548     return false;
 549   }
 550 
 551   size_t len = (size_t)(first_colon - path);
 552   assert(len + 2 <= MAX_PATH, "unexpected device specifier length");
 553   strncpy(root_path, path, len + 1);
 554   root_path[len + 1] = '\\';
 555   root_path[len + 2] = '\0';
 556 
 557   // check that we have something like "C:\" or "AA:\"
 558   assert(strlen(root_path) >= 3, "device specifier too short");
 559   assert(strchr(root_path, ':') != NULL, "bad device specifier format");
 560   assert(strchr(root_path, '\\') != NULL, "bad device specifier format");
 561 
 562   DWORD maxpath;
 563   DWORD flags;
 564 
 565   if (!GetVolumeInformation(root_path, NULL, 0, NULL, &maxpath,
 566                             &flags, fs_type, MAX_PATH)) {
 567     // we can't get information about the volume, so assume unsafe.
 568     if (PrintMiscellaneous && Verbose) {
 569       warning("could not get device information for %s: "
 570               " path = %s: lasterror = %d\n",
 571               root_path, path, GetLastError());
 572     }
 573     return false;
 574   }
 575 
 576   if ((flags & FS_PERSISTENT_ACLS) == 0) {
 577     // file system doesn't support ACLs, declare file system unsafe
 578     if (PrintMiscellaneous && Verbose) {
 579       warning("file system type %s on device %s does not support"
 580               " ACLs\n", fs_type, root_path);
 581     }
 582     return false;
 583   }
 584 
 585   if ((flags & FS_VOL_IS_COMPRESSED) != 0) {
 586     // file system is compressed, declare file system unsafe
 587     if (PrintMiscellaneous && Verbose) {
 588       warning("file system type %s on device %s is compressed\n",
 589               fs_type, root_path);
 590     }
 591     return false;
 592   }
 593 
 594   return true;
 595 }
 596 
 597 // cleanup stale shared memory resources
 598 //
 599 // This method attempts to remove all stale shared memory files in
 600 // the named user temporary directory. It scans the named directory
 601 // for files matching the pattern ^$[0-9]*$. For each file found, the
 602 // process id is extracted from the file name and a test is run to
 603 // determine if the process is alive. If the process is not alive,
 604 // any stale file resources are removed.
 605 //
 606 static void cleanup_sharedmem_resources(const char* dirname) {
 607 
 608   // open the user temp directory
 609   DIR* dirp = os::opendir(dirname);
 610 
 611   if (dirp == NULL) {
 612     // directory doesn't exist, so there is nothing to cleanup
 613     return;
 614   }
 615 
 616   if (!is_directory_secure(dirname)) {
 617     // the directory is not secure, don't attempt any cleanup
 618     return;
 619   }
 620 
 621   // for each entry in the directory that matches the expected file
 622   // name pattern, determine if the file resources are stale and if
 623   // so, remove the file resources. Note, instrumented HotSpot processes
 624   // for this user may start and/or terminate during this search and
 625   // remove or create new files in this directory. The behavior of this
 626   // loop under these conditions is dependent upon the implementation of
 627   // opendir/readdir.
 628   //
 629   struct dirent* entry;
 630   char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname));
 631   errno = 0;
 632   while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) {
 633 
 634     int pid = filename_to_pid(entry->d_name);
 635 
 636     if (pid == 0) {
 637 
 638       if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
 639 
 640         // attempt to remove all unexpected files, except "." and ".."
 641         remove_file(dirname, entry->d_name);
 642       }
 643 
 644       errno = 0;
 645       continue;
 646     }
 647 
 648     // we now have a file name that converts to a valid integer
 649     // that could represent a process id . if this process id
 650     // matches the current process id or the process is not running,
 651     // then remove the stale file resources.
 652     //
 653     // process liveness is detected by checking the exit status
 654     // of the process. if the process id is valid and the exit status
 655     // indicates that it is still running, the file file resources
 656     // are not removed. If the process id is invalid, or if we don't
 657     // have permissions to check the process status, or if the process
 658     // id is valid and the process has terminated, the the file resources
 659     // are assumed to be stale and are removed.
 660     //
 661     if (pid == os::current_process_id() || !is_alive(pid)) {
 662 
 663       // we can only remove the file resources. Any mapped views
 664       // of the file can only be unmapped by the processes that
 665       // opened those views and the file mapping object will not
 666       // get removed until all views are unmapped.
 667       //
 668       remove_file(dirname, entry->d_name);
 669     }
 670     errno = 0;
 671   }
 672   os::closedir(dirp);
 673   FREE_C_HEAP_ARRAY(char, dbuf);
 674 }
 675 
 676 // create a file mapping object with the requested name, and size
 677 // from the file represented by the given Handle object
 678 //
 679 static HANDLE create_file_mapping(const char* name, HANDLE fh, LPSECURITY_ATTRIBUTES fsa, size_t size) {
 680 
 681   DWORD lowSize = (DWORD)size;
 682   DWORD highSize = 0;
 683   HANDLE fmh = NULL;
 684 
 685   // Create a file mapping object with the given name. This function
 686   // will grow the file to the specified size.
 687   //
 688   fmh = CreateFileMapping(
 689                fh,                 /* HANDLE file handle for backing store */
 690                fsa,                /* LPSECURITY_ATTRIBUTES Not inheritable */
 691                PAGE_READWRITE,     /* DWORD protections */
 692                highSize,           /* DWORD High word of max size */
 693                lowSize,            /* DWORD Low word of max size */
 694                name);              /* LPCTSTR name for object */
 695 
 696   if (fmh == NULL) {
 697     if (PrintMiscellaneous && Verbose) {
 698       warning("CreateFileMapping failed, lasterror = %d\n", GetLastError());
 699     }
 700     return NULL;
 701   }
 702 
 703   if (GetLastError() == ERROR_ALREADY_EXISTS) {
 704 
 705     // a stale file mapping object was encountered. This object may be
 706     // owned by this or some other user and cannot be removed until
 707     // the other processes either exit or close their mapping objects
 708     // and/or mapped views of this mapping object.
 709     //
 710     if (PrintMiscellaneous && Verbose) {
 711       warning("file mapping already exists, lasterror = %d\n", GetLastError());
 712     }
 713 
 714     CloseHandle(fmh);
 715     return NULL;
 716   }
 717 
 718   return fmh;
 719 }
 720 
 721 
 722 // method to free the given security descriptor and the contained
 723 // access control list.
 724 //
 725 static void free_security_desc(PSECURITY_DESCRIPTOR pSD) {
 726 
 727   BOOL success, exists, isdefault;
 728   PACL pACL;
 729 
 730   if (pSD != NULL) {
 731 
 732     // get the access control list from the security descriptor
 733     success = GetSecurityDescriptorDacl(pSD, &exists, &pACL, &isdefault);
 734 
 735     // if an ACL existed and it was not a default acl, then it must
 736     // be an ACL we enlisted. free the resources.
 737     //
 738     if (success && exists && pACL != NULL && !isdefault) {
 739       FREE_C_HEAP_ARRAY(char, pACL);
 740     }
 741 
 742     // free the security descriptor
 743     FREE_C_HEAP_ARRAY(char, pSD);
 744   }
 745 }
 746 
 747 // method to free up a security attributes structure and any
 748 // contained security descriptors and ACL
 749 //
 750 static void free_security_attr(LPSECURITY_ATTRIBUTES lpSA) {
 751 
 752   if (lpSA != NULL) {
 753     // free the contained security descriptor and the ACL
 754     free_security_desc(lpSA->lpSecurityDescriptor);
 755     lpSA->lpSecurityDescriptor = NULL;
 756 
 757     // free the security attributes structure
 758     FREE_C_HEAP_ARRAY(char, lpSA);
 759   }
 760 }
 761 
 762 // get the user SID for the process indicated by the process handle
 763 //
 764 static PSID get_user_sid(HANDLE hProcess) {
 765 
 766   HANDLE hAccessToken;
 767   PTOKEN_USER token_buf = NULL;
 768   DWORD rsize = 0;
 769 
 770   if (hProcess == NULL) {
 771     return NULL;
 772   }
 773 
 774   // get the process token
 775   if (!OpenProcessToken(hProcess, TOKEN_READ, &hAccessToken)) {
 776     if (PrintMiscellaneous && Verbose) {
 777       warning("OpenProcessToken failure: lasterror = %d \n", GetLastError());
 778     }
 779     return NULL;
 780   }
 781 
 782   // determine the size of the token structured needed to retrieve
 783   // the user token information from the access token.
 784   //
 785   if (!GetTokenInformation(hAccessToken, TokenUser, NULL, rsize, &rsize)) {
 786     DWORD lasterror = GetLastError();
 787     if (lasterror != ERROR_INSUFFICIENT_BUFFER) {
 788       if (PrintMiscellaneous && Verbose) {
 789         warning("GetTokenInformation failure: lasterror = %d,"
 790                 " rsize = %d\n", lasterror, rsize);
 791       }
 792       CloseHandle(hAccessToken);
 793       return NULL;
 794     }
 795   }
 796 
 797   token_buf = (PTOKEN_USER) NEW_C_HEAP_ARRAY(char, rsize);
 798 
 799   // get the user token information
 800   if (!GetTokenInformation(hAccessToken, TokenUser, token_buf, rsize, &rsize)) {
 801     if (PrintMiscellaneous && Verbose) {
 802       warning("GetTokenInformation failure: lasterror = %d,"
 803               " rsize = %d\n", GetLastError(), rsize);
 804     }
 805     FREE_C_HEAP_ARRAY(char, token_buf);
 806     CloseHandle(hAccessToken);
 807     return NULL;
 808   }
 809 
 810   DWORD nbytes = GetLengthSid(token_buf->User.Sid);
 811   PSID pSID = NEW_C_HEAP_ARRAY(char, nbytes);
 812 
 813   if (!CopySid(nbytes, pSID, token_buf->User.Sid)) {
 814     if (PrintMiscellaneous && Verbose) {
 815       warning("GetTokenInformation failure: lasterror = %d,"
 816               " rsize = %d\n", GetLastError(), rsize);
 817     }
 818     FREE_C_HEAP_ARRAY(char, token_buf);
 819     FREE_C_HEAP_ARRAY(char, pSID);
 820     CloseHandle(hAccessToken);
 821     return NULL;
 822   }
 823 
 824   // close the access token.
 825   CloseHandle(hAccessToken);
 826   FREE_C_HEAP_ARRAY(char, token_buf);
 827 
 828   return pSID;
 829 }
 830 
 831 // structure used to consolidate access control entry information
 832 //
 833 typedef struct ace_data {
 834   PSID pSid;      // SID of the ACE
 835   DWORD mask;     // mask for the ACE
 836 } ace_data_t;
 837 
 838 
 839 // method to add an allow access control entry with the access rights
 840 // indicated in mask for the principal indicated in SID to the given
 841 // security descriptor. Much of the DACL handling was adapted from
 842 // the example provided here:
 843 //      http://support.microsoft.com/kb/102102/EN-US/
 844 //
 845 
 846 static bool add_allow_aces(PSECURITY_DESCRIPTOR pSD,
 847                            ace_data_t aces[], int ace_count) {
 848   PACL newACL = NULL;
 849   PACL oldACL = NULL;
 850 
 851   if (pSD == NULL) {
 852     return false;
 853   }
 854 
 855   BOOL exists, isdefault;
 856 
 857   // retrieve any existing access control list.
 858   if (!GetSecurityDescriptorDacl(pSD, &exists, &oldACL, &isdefault)) {
 859     if (PrintMiscellaneous && Verbose) {
 860       warning("GetSecurityDescriptor failure: lasterror = %d \n",
 861               GetLastError());
 862     }
 863     return false;
 864   }
 865 
 866   // get the size of the DACL
 867   ACL_SIZE_INFORMATION aclinfo;
 868 
 869   // GetSecurityDescriptorDacl may return true value for exists (lpbDaclPresent)
 870   // while oldACL is NULL for some case.
 871   if (oldACL == NULL) {
 872     exists = FALSE;
 873   }
 874 
 875   if (exists) {
 876     if (!GetAclInformation(oldACL, &aclinfo,
 877                            sizeof(ACL_SIZE_INFORMATION),
 878                            AclSizeInformation)) {
 879       if (PrintMiscellaneous && Verbose) {
 880         warning("GetAclInformation failure: lasterror = %d \n", GetLastError());
 881         return false;
 882       }
 883     }
 884   } else {
 885     aclinfo.AceCount = 0; // assume NULL DACL
 886     aclinfo.AclBytesFree = 0;
 887     aclinfo.AclBytesInUse = sizeof(ACL);
 888   }
 889 
 890   // compute the size needed for the new ACL
 891   // initial size of ACL is sum of the following:
 892   //   * size of ACL structure.
 893   //   * size of each ACE structure that ACL is to contain minus the sid
 894   //     sidStart member (DWORD) of the ACE.
 895   //   * length of the SID that each ACE is to contain.
 896   DWORD newACLsize = aclinfo.AclBytesInUse +
 897                         (sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD)) * ace_count;
 898   for (int i = 0; i < ace_count; i++) {
 899      assert(aces[i].pSid != 0, "pSid should not be 0");
 900      newACLsize += GetLengthSid(aces[i].pSid);
 901   }
 902 
 903   // create the new ACL
 904   newACL = (PACL) NEW_C_HEAP_ARRAY(char, newACLsize);
 905 
 906   if (!InitializeAcl(newACL, newACLsize, ACL_REVISION)) {
 907     if (PrintMiscellaneous && Verbose) {
 908       warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
 909     }
 910     FREE_C_HEAP_ARRAY(char, newACL);
 911     return false;
 912   }
 913 
 914   unsigned int ace_index = 0;
 915   // copy any existing ACEs from the old ACL (if any) to the new ACL.
 916   if (aclinfo.AceCount != 0) {
 917     while (ace_index < aclinfo.AceCount) {
 918       LPVOID ace;
 919       if (!GetAce(oldACL, ace_index, &ace)) {
 920         if (PrintMiscellaneous && Verbose) {
 921           warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
 922         }
 923         FREE_C_HEAP_ARRAY(char, newACL);
 924         return false;
 925       }
 926       if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceFlags && INHERITED_ACE) {
 927         // this is an inherited, allowed ACE; break from loop so we can
 928         // add the new access allowed, non-inherited ACE in the correct
 929         // position, immediately following all non-inherited ACEs.
 930         break;
 931       }
 932 
 933       // determine if the SID of this ACE matches any of the SIDs
 934       // for which we plan to set ACEs.
 935       int matches = 0;
 936       for (int i = 0; i < ace_count; i++) {
 937         if (EqualSid(aces[i].pSid, &(((ACCESS_ALLOWED_ACE *)ace)->SidStart))) {
 938           matches++;
 939           break;
 940         }
 941       }
 942 
 943       // if there are no SID matches, then add this existing ACE to the new ACL
 944       if (matches == 0) {
 945         if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
 946                     ((PACE_HEADER)ace)->AceSize)) {
 947           if (PrintMiscellaneous && Verbose) {
 948             warning("AddAce failure: lasterror = %d \n", GetLastError());
 949           }
 950           FREE_C_HEAP_ARRAY(char, newACL);
 951           return false;
 952         }
 953       }
 954       ace_index++;
 955     }
 956   }
 957 
 958   // add the passed-in access control entries to the new ACL
 959   for (int i = 0; i < ace_count; i++) {
 960     if (!AddAccessAllowedAce(newACL, ACL_REVISION,
 961                              aces[i].mask, aces[i].pSid)) {
 962       if (PrintMiscellaneous && Verbose) {
 963         warning("AddAccessAllowedAce failure: lasterror = %d \n",
 964                 GetLastError());
 965       }
 966       FREE_C_HEAP_ARRAY(char, newACL);
 967       return false;
 968     }
 969   }
 970 
 971   // now copy the rest of the inherited ACEs from the old ACL
 972   if (aclinfo.AceCount != 0) {
 973     // picking up at ace_index, where we left off in the
 974     // previous ace_index loop
 975     while (ace_index < aclinfo.AceCount) {
 976       LPVOID ace;
 977       if (!GetAce(oldACL, ace_index, &ace)) {
 978         if (PrintMiscellaneous && Verbose) {
 979           warning("InitializeAcl failure: lasterror = %d \n", GetLastError());
 980         }
 981         FREE_C_HEAP_ARRAY(char, newACL);
 982         return false;
 983       }
 984       if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace,
 985                   ((PACE_HEADER)ace)->AceSize)) {
 986         if (PrintMiscellaneous && Verbose) {
 987           warning("AddAce failure: lasterror = %d \n", GetLastError());
 988         }
 989         FREE_C_HEAP_ARRAY(char, newACL);
 990         return false;
 991       }
 992       ace_index++;
 993     }
 994   }
 995 
 996   // add the new ACL to the security descriptor.
 997   if (!SetSecurityDescriptorDacl(pSD, TRUE, newACL, FALSE)) {
 998     if (PrintMiscellaneous && Verbose) {
 999       warning("SetSecurityDescriptorDacl failure:"
1000               " lasterror = %d \n", GetLastError());
1001     }
1002     FREE_C_HEAP_ARRAY(char, newACL);
1003     return false;
1004   }
1005 
1006   // if running on windows 2000 or later, set the automatic inheritance
1007   // control flags.
1008   SetSecurityDescriptorControlFnPtr _SetSecurityDescriptorControl;
1009   _SetSecurityDescriptorControl = (SetSecurityDescriptorControlFnPtr)
1010        GetProcAddress(GetModuleHandle(TEXT("advapi32.dll")),
1011                       "SetSecurityDescriptorControl");
1012 
1013   if (_SetSecurityDescriptorControl != NULL) {
1014     // We do not want to further propagate inherited DACLs, so making them
1015     // protected prevents that.
1016     if (!_SetSecurityDescriptorControl(pSD, SE_DACL_PROTECTED,
1017                                             SE_DACL_PROTECTED)) {
1018       if (PrintMiscellaneous && Verbose) {
1019         warning("SetSecurityDescriptorControl failure:"
1020                 " lasterror = %d \n", GetLastError());
1021       }
1022       FREE_C_HEAP_ARRAY(char, newACL);
1023       return false;
1024     }
1025   }
1026    // Note, the security descriptor maintains a reference to the newACL, not
1027    // a copy of it. Therefore, the newACL is not freed here. It is freed when
1028    // the security descriptor containing its reference is freed.
1029    //
1030    return true;
1031 }
1032 
1033 // method to create a security attributes structure, which contains a
1034 // security descriptor and an access control list comprised of 0 or more
1035 // access control entries. The method take an array of ace_data structures
1036 // that indicate the ACE to be added to the security descriptor.
1037 //
1038 // the caller must free the resources associated with the security
1039 // attributes structure created by this method by calling the
1040 // free_security_attr() method.
1041 //
1042 static LPSECURITY_ATTRIBUTES make_security_attr(ace_data_t aces[], int count) {
1043 
1044   // allocate space for a security descriptor
1045   PSECURITY_DESCRIPTOR pSD = (PSECURITY_DESCRIPTOR)
1046                          NEW_C_HEAP_ARRAY(char, SECURITY_DESCRIPTOR_MIN_LENGTH);
1047 
1048   // initialize the security descriptor
1049   if (!InitializeSecurityDescriptor(pSD, SECURITY_DESCRIPTOR_REVISION)) {
1050     if (PrintMiscellaneous && Verbose) {
1051       warning("InitializeSecurityDescriptor failure: "
1052               "lasterror = %d \n", GetLastError());
1053     }
1054     free_security_desc(pSD);
1055     return NULL;
1056   }
1057 
1058   // add the access control entries
1059   if (!add_allow_aces(pSD, aces, count)) {
1060     free_security_desc(pSD);
1061     return NULL;
1062   }
1063 
1064   // allocate and initialize the security attributes structure and
1065   // return it to the caller.
1066   //
1067   LPSECURITY_ATTRIBUTES lpSA = (LPSECURITY_ATTRIBUTES)
1068                             NEW_C_HEAP_ARRAY(char, sizeof(SECURITY_ATTRIBUTES));
1069   lpSA->nLength = sizeof(SECURITY_ATTRIBUTES);
1070   lpSA->lpSecurityDescriptor = pSD;
1071   lpSA->bInheritHandle = FALSE;
1072 
1073   return(lpSA);
1074 }
1075 
1076 // method to create a security attributes structure with a restrictive
1077 // access control list that creates a set access rights for the user/owner
1078 // of the securable object and a separate set access rights for everyone else.
1079 // also provides for full access rights for the administrator group.
1080 //
1081 // the caller must free the resources associated with the security
1082 // attributes structure created by this method by calling the
1083 // free_security_attr() method.
1084 //
1085 
1086 static LPSECURITY_ATTRIBUTES make_user_everybody_admin_security_attr(
1087                                 DWORD umask, DWORD emask, DWORD amask) {
1088 
1089   ace_data_t aces[3];
1090 
1091   // initialize the user ace data
1092   aces[0].pSid = get_user_sid(GetCurrentProcess());
1093   aces[0].mask = umask;
1094 
1095   if (aces[0].pSid == 0)
1096     return NULL;
1097 
1098   // get the well known SID for BUILTIN\Administrators
1099   PSID administratorsSid = NULL;
1100   SID_IDENTIFIER_AUTHORITY SIDAuthAdministrators = SECURITY_NT_AUTHORITY;
1101 
1102   if (!AllocateAndInitializeSid( &SIDAuthAdministrators, 2,
1103            SECURITY_BUILTIN_DOMAIN_RID,
1104            DOMAIN_ALIAS_RID_ADMINS,
1105            0, 0, 0, 0, 0, 0, &administratorsSid)) {
1106 
1107     if (PrintMiscellaneous && Verbose) {
1108       warning("AllocateAndInitializeSid failure: "
1109               "lasterror = %d \n", GetLastError());
1110     }
1111     return NULL;
1112   }
1113 
1114   // initialize the ace data for administrator group
1115   aces[1].pSid = administratorsSid;
1116   aces[1].mask = amask;
1117 
1118   // get the well known SID for the universal Everybody
1119   PSID everybodySid = NULL;
1120   SID_IDENTIFIER_AUTHORITY SIDAuthEverybody = SECURITY_WORLD_SID_AUTHORITY;
1121 
1122   if (!AllocateAndInitializeSid( &SIDAuthEverybody, 1, SECURITY_WORLD_RID,
1123            0, 0, 0, 0, 0, 0, 0, &everybodySid)) {
1124 
1125     if (PrintMiscellaneous && Verbose) {
1126       warning("AllocateAndInitializeSid failure: "
1127               "lasterror = %d \n", GetLastError());
1128     }
1129     return NULL;
1130   }
1131 
1132   // initialize the ace data for everybody else.
1133   aces[2].pSid = everybodySid;
1134   aces[2].mask = emask;
1135 
1136   // create a security attributes structure with access control
1137   // entries as initialized above.
1138   LPSECURITY_ATTRIBUTES lpSA = make_security_attr(aces, 3);
1139   FREE_C_HEAP_ARRAY(char, aces[0].pSid);
1140   FreeSid(everybodySid);
1141   FreeSid(administratorsSid);
1142   return(lpSA);
1143 }
1144 
1145 
1146 // method to create the security attributes structure for restricting
1147 // access to the user temporary directory.
1148 //
1149 // the caller must free the resources associated with the security
1150 // attributes structure created by this method by calling the
1151 // free_security_attr() method.
1152 //
1153 static LPSECURITY_ATTRIBUTES make_tmpdir_security_attr() {
1154 
1155   // create full access rights for the user/owner of the directory
1156   // and read-only access rights for everybody else. This is
1157   // effectively equivalent to UNIX 755 permissions on a directory.
1158   //
1159   DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_ALL_ACCESS;
1160   DWORD emask = GENERIC_READ | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1161   DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1162 
1163   return make_user_everybody_admin_security_attr(umask, emask, amask);
1164 }
1165 
1166 // method to create the security attributes structure for restricting
1167 // access to the shared memory backing store file.
1168 //
1169 // the caller must free the resources associated with the security
1170 // attributes structure created by this method by calling the
1171 // free_security_attr() method.
1172 //
1173 static LPSECURITY_ATTRIBUTES make_file_security_attr() {
1174 
1175   // create extensive access rights for the user/owner of the file
1176   // and attribute read-only access rights for everybody else. This
1177   // is effectively equivalent to UNIX 600 permissions on a file.
1178   //
1179   DWORD umask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1180   DWORD emask = STANDARD_RIGHTS_READ | FILE_READ_ATTRIBUTES |
1181                  FILE_READ_EA | FILE_LIST_DIRECTORY | FILE_TRAVERSE;
1182   DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS;
1183 
1184   return make_user_everybody_admin_security_attr(umask, emask, amask);
1185 }
1186 
1187 // method to create the security attributes structure for restricting
1188 // access to the name shared memory file mapping object.
1189 //
1190 // the caller must free the resources associated with the security
1191 // attributes structure created by this method by calling the
1192 // free_security_attr() method.
1193 //
1194 static LPSECURITY_ATTRIBUTES make_smo_security_attr() {
1195 
1196   // create extensive access rights for the user/owner of the shared
1197   // memory object and attribute read-only access rights for everybody
1198   // else. This is effectively equivalent to UNIX 600 permissions on
1199   // on the shared memory object.
1200   //
1201   DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_MAP_ALL_ACCESS;
1202   DWORD emask = STANDARD_RIGHTS_READ; // attributes only
1203   DWORD amask = STANDARD_RIGHTS_ALL | FILE_MAP_ALL_ACCESS;
1204 
1205   return make_user_everybody_admin_security_attr(umask, emask, amask);
1206 }
1207 
1208 // make the user specific temporary directory
1209 //
1210 static bool make_user_tmp_dir(const char* dirname) {
1211 
1212 
1213   LPSECURITY_ATTRIBUTES pDirSA = make_tmpdir_security_attr();
1214   if (pDirSA == NULL) {
1215     return false;
1216   }
1217 
1218 
1219   // create the directory with the given security attributes
1220   if (!CreateDirectory(dirname, pDirSA)) {
1221     DWORD lasterror = GetLastError();
1222     if (lasterror == ERROR_ALREADY_EXISTS) {
1223       // The directory already exists and was probably created by another
1224       // JVM instance. However, this could also be the result of a
1225       // deliberate symlink. Verify that the existing directory is safe.
1226       //
1227       if (!is_directory_secure(dirname)) {
1228         // directory is not secure
1229         if (PrintMiscellaneous && Verbose) {
1230           warning("%s directory is insecure\n", dirname);
1231         }
1232         return false;
1233       }
1234       // The administrator should be able to delete this directory.
1235       // But the directory created by previous version of JVM may not
1236       // have permission for administrators to delete this directory.
1237       // So add full permission to the administrator. Also setting new
1238       // DACLs might fix the corrupted the DACLs.
1239       SECURITY_INFORMATION secInfo = DACL_SECURITY_INFORMATION;
1240       if (!SetFileSecurity(dirname, secInfo, pDirSA->lpSecurityDescriptor)) {
1241         if (PrintMiscellaneous && Verbose) {
1242           lasterror = GetLastError();
1243           warning("SetFileSecurity failed for %s directory.  lasterror %d \n",
1244                                                         dirname, lasterror);
1245         }
1246       }
1247     }
1248     else {
1249       if (PrintMiscellaneous && Verbose) {
1250         warning("CreateDirectory failed: %d\n", GetLastError());
1251       }
1252       return false;
1253     }
1254   }
1255 
1256   // free the security attributes structure
1257   free_security_attr(pDirSA);
1258 
1259   return true;
1260 }
1261 
1262 // create the shared memory resources
1263 //
1264 // This function creates the shared memory resources. This includes
1265 // the backing store file and the file mapping shared memory object.
1266 //
1267 static HANDLE create_sharedmem_resources(const char* dirname, const char* filename, const char* objectname, size_t size) {
1268 
1269   HANDLE fh = INVALID_HANDLE_VALUE;
1270   HANDLE fmh = NULL;
1271 
1272 
1273   // create the security attributes for the backing store file
1274   LPSECURITY_ATTRIBUTES lpFileSA = make_file_security_attr();
1275   if (lpFileSA == NULL) {
1276     return NULL;
1277   }
1278 
1279   // create the security attributes for the shared memory object
1280   LPSECURITY_ATTRIBUTES lpSmoSA = make_smo_security_attr();
1281   if (lpSmoSA == NULL) {
1282     free_security_attr(lpFileSA);
1283     return NULL;
1284   }
1285 
1286   // create the user temporary directory
1287   if (!make_user_tmp_dir(dirname)) {
1288     // could not make/find the directory or the found directory
1289     // was not secure
1290     return NULL;
1291   }
1292 
1293   // Create the file - the FILE_FLAG_DELETE_ON_CLOSE flag allows the
1294   // file to be deleted by the last process that closes its handle to
1295   // the file. This is important as the apis do not allow a terminating
1296   // JVM being monitored by another process to remove the file name.
1297   //
1298   // the FILE_SHARE_DELETE share mode is valid only in winnt
1299   //
1300   fh = CreateFile(
1301              filename,                   /* LPCTSTR file name */
1302 
1303              GENERIC_READ|GENERIC_WRITE, /* DWORD desired access */
1304 
1305              (os::win32::is_nt() ? FILE_SHARE_DELETE : 0)|
1306              FILE_SHARE_READ,            /* DWORD share mode, future READONLY
1307                                           * open operations allowed
1308                                           */
1309              lpFileSA,                   /* LPSECURITY security attributes */
1310              CREATE_ALWAYS,              /* DWORD creation disposition
1311                                           * create file, if it already
1312                                           * exists, overwrite it.
1313                                           */
1314              FILE_FLAG_DELETE_ON_CLOSE,  /* DWORD flags and attributes */
1315 
1316              NULL);                      /* HANDLE template file access */
1317 
1318   free_security_attr(lpFileSA);
1319 
1320   if (fh == INVALID_HANDLE_VALUE) {
1321     DWORD lasterror = GetLastError();
1322     if (PrintMiscellaneous && Verbose) {
1323       warning("could not create file %s: %d\n", filename, lasterror);
1324     }
1325     return NULL;
1326   }
1327 
1328   // try to create the file mapping
1329   fmh = create_file_mapping(objectname, fh, lpSmoSA, size);
1330 
1331   free_security_attr(lpSmoSA);
1332 
1333   if (fmh == NULL) {
1334     // closing the file handle here will decrement the reference count
1335     // on the file. When all processes accessing the file close their
1336     // handle to it, the reference count will decrement to 0 and the
1337     // OS will delete the file. These semantics are requested by the
1338     // FILE_FLAG_DELETE_ON_CLOSE flag in CreateFile call above.
1339     CloseHandle(fh);
1340     fh = NULL;
1341     return NULL;









1342   }






1343 
















1344   // the file has been successfully created and the file mapping
1345   // object has been created.
1346   sharedmem_fileHandle = fh;
1347   sharedmem_fileName = strdup(filename);
1348 
1349   return fmh;
1350 }
1351 
1352 // open the shared memory object for the given vmid.
1353 //
1354 static HANDLE open_sharedmem_object(const char* objectname, DWORD ofm_access, TRAPS) {
1355 
1356   HANDLE fmh;
1357 
1358   // open the file mapping with the requested mode
1359   fmh = OpenFileMapping(
1360                ofm_access,       /* DWORD access mode */
1361                FALSE,            /* BOOL inherit flag - Do not allow inherit */
1362                objectname);      /* name for object */
1363 
1364   if (fmh == NULL) {
1365     if (PrintMiscellaneous && Verbose) {
1366       warning("OpenFileMapping failed for shared memory object %s:"
1367               " lasterror = %d\n", objectname, GetLastError());
1368     }
1369     THROW_MSG_(vmSymbols::java_lang_Exception(),
1370                "Could not open PerfMemory", INVALID_HANDLE_VALUE);
1371   }
1372 
1373   return fmh;;
1374 }
1375 
1376 // create a named shared memory region
1377 //
1378 // On Win32, a named shared memory object has a name space that
1379 // is independent of the file system name space. Shared memory object,
1380 // or more precisely, file mapping objects, provide no mechanism to
1381 // inquire the size of the memory region. There is also no api to
1382 // enumerate the memory regions for various processes.
1383 //
1384 // This implementation utilizes the shared memory name space in parallel
1385 // with the file system name space. This allows us to determine the
1386 // size of the shared memory region from the size of the file and it
1387 // allows us to provide a common, file system based name space for
1388 // shared memory across platforms.
1389 //
1390 static char* mapping_create_shared(size_t size) {
1391 
1392   void *mapAddress;
1393   int vmid = os::current_process_id();
1394 
1395   // get the name of the user associated with this process
1396   char* user = get_user_name();
1397 
1398   if (user == NULL) {
1399     return NULL;
1400   }
1401 
1402   // construct the name of the user specific temporary directory
1403   char* dirname = get_user_tmp_dir(user);
1404 
1405   // check that the file system is secure - i.e. it supports ACLs.
1406   if (!is_filesystem_secure(dirname)) {
1407     return NULL;
1408   }
1409 
1410   // create the names of the backing store files and for the
1411   // share memory object.
1412   //
1413   char* filename = get_sharedmem_filename(dirname, vmid);
1414   char* objectname = get_sharedmem_objectname(user, vmid);
1415 
1416   // cleanup any stale shared memory resources
1417   cleanup_sharedmem_resources(dirname);
1418 
1419   assert(((size != 0) && (size % os::vm_page_size() == 0)),
1420          "unexpected PerfMemry region size");
1421 
1422   FREE_C_HEAP_ARRAY(char, user);
1423 
1424   // create the shared memory resources
1425   sharedmem_fileMapHandle =
1426                create_sharedmem_resources(dirname, filename, objectname, size);
1427 
1428   FREE_C_HEAP_ARRAY(char, filename);
1429   FREE_C_HEAP_ARRAY(char, objectname);
1430   FREE_C_HEAP_ARRAY(char, dirname);
1431 
1432   if (sharedmem_fileMapHandle == NULL) {
1433     return NULL;
1434   }
1435 
1436   // map the file into the address space
1437   mapAddress = MapViewOfFile(
1438                    sharedmem_fileMapHandle, /* HANDLE = file mapping object */
1439                    FILE_MAP_ALL_ACCESS,     /* DWORD access flags */
1440                    0,                       /* DWORD High word of offset */
1441                    0,                       /* DWORD Low word of offset */
1442                    (DWORD)size);            /* DWORD Number of bytes to map */
1443 
1444   if (mapAddress == NULL) {
1445     if (PrintMiscellaneous && Verbose) {
1446       warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1447     }
1448     CloseHandle(sharedmem_fileMapHandle);
1449     sharedmem_fileMapHandle = NULL;
1450     return NULL;
1451   }
1452 
1453   // clear the shared memory region
1454   (void)memset(mapAddress, '\0', size);
1455 
1456   return (char*) mapAddress;
1457 }
1458 
1459 // this method deletes the file mapping object.
1460 //
1461 static void delete_file_mapping(char* addr, size_t size) {
1462 
1463   // cleanup the persistent shared memory resources. since DestroyJavaVM does
1464   // not support unloading of the JVM, unmapping of the memory resource is not
1465   // performed. The memory will be reclaimed by the OS upon termination of all
1466   // processes mapping the resource. The file mapping handle and the file
1467   // handle are closed here to expedite the remove of the file by the OS. The
1468   // file is not removed directly because it was created with
1469   // FILE_FLAG_DELETE_ON_CLOSE semantics and any attempt to remove it would
1470   // be unsuccessful.
1471 
1472   // close the fileMapHandle. the file mapping will still be retained
1473   // by the OS as long as any other JVM processes has an open file mapping
1474   // handle or a mapped view of the file.
1475   //
1476   if (sharedmem_fileMapHandle != NULL) {
1477     CloseHandle(sharedmem_fileMapHandle);
1478     sharedmem_fileMapHandle = NULL;
1479   }
1480 
1481   // close the file handle. This will decrement the reference count on the
1482   // backing store file. When the reference count decrements to 0, the OS
1483   // will delete the file. These semantics apply because the file was
1484   // created with the FILE_FLAG_DELETE_ON_CLOSE flag.
1485   //
1486   if (sharedmem_fileHandle != INVALID_HANDLE_VALUE) {
1487     CloseHandle(sharedmem_fileHandle);
1488     sharedmem_fileHandle = INVALID_HANDLE_VALUE;
1489   }
1490 }
1491 
1492 // this method determines the size of the shared memory file
1493 //
1494 static size_t sharedmem_filesize(const char* filename, TRAPS) {
1495 
1496   struct stat statbuf;
1497 
1498   // get the file size
1499   //
1500   // on win95/98/me, _stat returns a file size of 0 bytes, but on
1501   // winnt/2k the appropriate file size is returned. support for
1502   // the sharable aspects of performance counters was abandonded
1503   // on the non-nt win32 platforms due to this and other api
1504   // inconsistencies
1505   //
1506   if (::stat(filename, &statbuf) == OS_ERR) {
1507     if (PrintMiscellaneous && Verbose) {
1508       warning("stat %s failed: %s\n", filename, strerror(errno));
1509     }
1510     THROW_MSG_0(vmSymbols::java_io_IOException(),
1511                 "Could not determine PerfMemory size");
1512   }
1513 
1514   if ((statbuf.st_size == 0) || (statbuf.st_size % os::vm_page_size() != 0)) {
1515     if (PrintMiscellaneous && Verbose) {
1516       warning("unexpected file size: size = " SIZE_FORMAT "\n",
1517               statbuf.st_size);
1518     }
1519     THROW_MSG_0(vmSymbols::java_lang_Exception(),
1520                 "Invalid PerfMemory size");
1521   }
1522 
1523   return statbuf.st_size;
1524 }
1525 
1526 // this method opens a file mapping object and maps the object
1527 // into the address space of the process
1528 //
1529 static void open_file_mapping(const char* user, int vmid,
1530                               PerfMemory::PerfMemoryMode mode,
1531                               char** addrp, size_t* sizep, TRAPS) {
1532 
1533   ResourceMark rm;
1534 
1535   void *mapAddress = 0;
1536   size_t size;
1537   HANDLE fmh;
1538   DWORD ofm_access;
1539   DWORD mv_access;
1540   const char* luser = NULL;
1541 
1542   if (mode == PerfMemory::PERF_MODE_RO) {
1543     ofm_access = FILE_MAP_READ;
1544     mv_access = FILE_MAP_READ;
1545   }
1546   else if (mode == PerfMemory::PERF_MODE_RW) {
1547 #ifdef LATER
1548     ofm_access = FILE_MAP_READ | FILE_MAP_WRITE;
1549     mv_access = FILE_MAP_READ | FILE_MAP_WRITE;
1550 #else
1551     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1552               "Unsupported access mode");
1553 #endif
1554   }
1555   else {
1556     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1557               "Illegal access mode");
1558   }
1559 
1560   // if a user name wasn't specified, then find the user name for
1561   // the owner of the target vm.
1562   if (user == NULL || strlen(user) == 0) {
1563     luser = get_user_name(vmid);
1564   }
1565   else {
1566     luser = user;
1567   }
1568 
1569   if (luser == NULL) {
1570     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1571               "Could not map vmid to user name");
1572   }
1573 
1574   // get the names for the resources for the target vm
1575   char* dirname = get_user_tmp_dir(luser);
1576 
1577   // since we don't follow symbolic links when creating the backing
1578   // store file, we also don't following them when attaching
1579   //
1580   if (!is_directory_secure(dirname)) {
1581     FREE_C_HEAP_ARRAY(char, dirname);
1582     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1583               "Process not found");
1584   }
1585 
1586   char* filename = get_sharedmem_filename(dirname, vmid);
1587   char* objectname = get_sharedmem_objectname(luser, vmid);
1588 
1589   // copy heap memory to resource memory. the objectname and
1590   // filename are passed to methods that may throw exceptions.
1591   // using resource arrays for these names prevents the leaks
1592   // that would otherwise occur.
1593   //
1594   char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
1595   char* robjectname = NEW_RESOURCE_ARRAY(char, strlen(objectname) + 1);
1596   strcpy(rfilename, filename);
1597   strcpy(robjectname, objectname);
1598 
1599   // free the c heap resources that are no longer needed
1600   if (luser != user) FREE_C_HEAP_ARRAY(char, luser);
1601   FREE_C_HEAP_ARRAY(char, dirname);
1602   FREE_C_HEAP_ARRAY(char, filename);
1603   FREE_C_HEAP_ARRAY(char, objectname);
1604 
1605   if (*sizep == 0) {
1606     size = sharedmem_filesize(rfilename, CHECK);
1607     assert(size != 0, "unexpected size");
1608   }
1609 
1610   // Open the file mapping object with the given name
1611   fmh = open_sharedmem_object(robjectname, ofm_access, CHECK);
1612 
1613   assert(fmh != INVALID_HANDLE_VALUE, "unexpected handle value");
1614 
1615   // map the entire file into the address space
1616   mapAddress = MapViewOfFile(
1617                  fmh,             /* HANDLE Handle of file mapping object */
1618                  mv_access,       /* DWORD access flags */
1619                  0,               /* DWORD High word of offset */
1620                  0,               /* DWORD Low word of offset */
1621                  size);           /* DWORD Number of bytes to map */
1622 
1623   if (mapAddress == NULL) {
1624     if (PrintMiscellaneous && Verbose) {
1625       warning("MapViewOfFile failed, lasterror = %d\n", GetLastError());
1626     }
1627     CloseHandle(fmh);
1628     THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
1629               "Could not map PerfMemory");
1630   }
1631 
1632   *addrp = (char*)mapAddress;
1633   *sizep = size;
1634 
1635   // File mapping object can be closed at this time without
1636   // invalidating the mapped view of the file
1637   CloseHandle(fmh);
1638 
1639   if (PerfTraceMemOps) {
1640     tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at "
1641                INTPTR_FORMAT "\n", size, vmid, mapAddress);
1642   }
1643 }
1644 
1645 // this method unmaps the the mapped view of the the
1646 // file mapping object.
1647 //
1648 static void remove_file_mapping(char* addr) {
1649 
1650   // the file mapping object was closed in open_file_mapping()
1651   // after the file map view was created. We only need to
1652   // unmap the file view here.
1653   UnmapViewOfFile(addr);
1654 }
1655 
1656 // create the PerfData memory region in shared memory.
1657 static char* create_shared_memory(size_t size) {
1658 
1659   return mapping_create_shared(size);
1660 }
1661 
1662 // release a named, shared memory region
1663 //
1664 void delete_shared_memory(char* addr, size_t size) {
1665 
1666   delete_file_mapping(addr, size);
1667 }
1668 
1669 
1670 
1671 
1672 // create the PerfData memory region
1673 //
1674 // This method creates the memory region used to store performance
1675 // data for the JVM. The memory may be created in standard or
1676 // shared memory.
1677 //
1678 void PerfMemory::create_memory_region(size_t size) {
1679 
1680   if (PerfDisableSharedMem || !os::win32::is_nt()) {
1681     // do not share the memory for the performance data.
1682     PerfDisableSharedMem = true;
1683     _start = create_standard_memory(size);
1684   }
1685   else {
1686     _start = create_shared_memory(size);
1687     if (_start == NULL) {
1688 
1689       // creation of the shared memory region failed, attempt
1690       // to create a contiguous, non-shared memory region instead.
1691       //
1692       if (PrintMiscellaneous && Verbose) {
1693         warning("Reverting to non-shared PerfMemory region.\n");
1694       }
1695       PerfDisableSharedMem = true;
1696       _start = create_standard_memory(size);
1697     }
1698   }
1699 
1700   if (_start != NULL) _capacity = size;
1701 
1702 }
1703 
1704 // delete the PerfData memory region
1705 //
1706 // This method deletes the memory region used to store performance
1707 // data for the JVM. The memory region indicated by the <address, size>
1708 // tuple will be inaccessible after a call to this method.
1709 //
1710 void PerfMemory::delete_memory_region() {
1711 
1712   assert((start() != NULL && capacity() > 0), "verify proper state");
1713 
1714   // If user specifies PerfDataSaveFile, it will save the performance data
1715   // to the specified file name no matter whether PerfDataSaveToFile is specified
1716   // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
1717   // -XX:+PerfDataSaveToFile.
1718   if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
1719     save_memory_to_file(start(), capacity());
1720   }
1721 
1722   if (PerfDisableSharedMem) {
1723     delete_standard_memory(start(), capacity());
1724   }
1725   else {
1726     delete_shared_memory(start(), capacity());
1727   }
1728 }
1729 
1730 // attach to the PerfData memory region for another JVM
1731 //
1732 // This method returns an <address, size> tuple that points to
1733 // a memory buffer that is kept reasonably synchronized with
1734 // the PerfData memory region for the indicated JVM. This
1735 // buffer may be kept in synchronization via shared memory
1736 // or some other mechanism that keeps the buffer updated.
1737 //
1738 // If the JVM chooses not to support the attachability feature,
1739 // this method should throw an UnsupportedOperation exception.
1740 //
1741 // This implementation utilizes named shared memory to map
1742 // the indicated process's PerfData memory region into this JVMs
1743 // address space.
1744 //
1745 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode,
1746                         char** addrp, size_t* sizep, TRAPS) {
1747 
1748   if (vmid == 0 || vmid == os::current_process_id()) {
1749      *addrp = start();
1750      *sizep = capacity();
1751      return;
1752   }
1753 
1754   open_file_mapping(user, vmid, mode, addrp, sizep, CHECK);
1755 }
1756 
1757 // detach from the PerfData memory region of another JVM
1758 //
1759 // This method detaches the PerfData memory region of another
1760 // JVM, specified as an <address, size> tuple of a buffer
1761 // in this process's address space. This method may perform
1762 // arbitrary actions to accomplish the detachment. The memory
1763 // region specified by <address, size> will be inaccessible after
1764 // a call to this method.
1765 //
1766 // If the JVM chooses not to support the attachability feature,
1767 // this method should throw an UnsupportedOperation exception.
1768 //
1769 // This implementation utilizes named shared memory to detach
1770 // the indicated process's PerfData memory region from this
1771 // process's address space.
1772 //
1773 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
1774 
1775   assert(addr != 0, "address sanity check");
1776   assert(bytes > 0, "capacity sanity check");
1777 
1778   if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
1779     // prevent accidental detachment of this process's PerfMemory region
1780     return;
1781   }
1782 
1783   remove_file_mapping(addr);
1784 }
1785 
1786 char* PerfMemory::backing_store_filename() {
1787   return sharedmem_fileName;
1788 }
--- EOF ---