1 /* 2 * Copyright (c) 2001, 2018, 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 if (latest_user != NULL) 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_ARRAY(char, 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 = (LPSECURITY_ATTRIBUTES) 1077 NEW_C_HEAP_ARRAY(char, sizeof(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_lang_Exception(), 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 }