perfMemory_windows.cpp revision 3465:d2a62e0f25eb
1/* 2 * Copyright (c) 2001, 2011, 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 41typedef 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// 50static 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// 73static 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// 86static 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, mtInternal); 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 147static HANDLE sharedmem_fileMapHandle = NULL; 148static HANDLE sharedmem_fileHandle = INVALID_HANDLE_VALUE; 149static 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// 155static 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, mtInternal); 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// 171static 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// 207static 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// 264static 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, mtInternal); 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// 298static char* get_user_name_slow(int vmid) { 299 300 // directory search 301 char* latest_user = NULL; 302 time_t latest_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), mtInternal); 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, mtInternal); 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, mtInternal); 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, mtInternal); 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), mtInternal); 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, mtInternal); 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, mtInternal); 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, mtInternal); 375 continue; 376 } 377 378 // If we found a matching file with a newer creation time, then 379 // save the user name. The newer creation time indicates that 380 // we found a newer incarnation of the process associated with 381 // vmid. Due to the way that Windows recycles pids and the fact 382 // that we can't delete the file from the file system namespace 383 // until last close, it is possible for there to be more than 384 // one hsperfdata file with a name matching vmid (diff users). 385 // 386 // We no longer ignore hsperfdata files where (st_size == 0). 387 // In this function, all we're trying to do is determine the 388 // name of the user that owns the process associated with vmid 389 // so the size doesn't matter. Very rarely, we have observed 390 // hsperfdata files where (st_size == 0) and the st_size field 391 // later becomes the expected value. 392 // 393 if (statbuf.st_ctime > latest_ctime) { 394 char* user = strchr(dentry->d_name, '_') + 1; 395 396 if (latest_user != NULL) FREE_C_HEAP_ARRAY(char, latest_user, mtInternal); 397 latest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal); 398 399 strcpy(latest_user, user); 400 latest_ctime = statbuf.st_ctime; 401 } 402 403 FREE_C_HEAP_ARRAY(char, filename, mtInternal); 404 } 405 } 406 os::closedir(subdirp); 407 FREE_C_HEAP_ARRAY(char, udbuf, mtInternal); 408 FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal); 409 } 410 os::closedir(tmpdirp); 411 FREE_C_HEAP_ARRAY(char, tdbuf, mtInternal); 412 413 return(latest_user); 414} 415 416// return the name of the user that owns the process identified by vmid. 417// 418// note: this method should only be used via the Perf native methods. 419// There are various costs to this method and limiting its use to the 420// Perf native methods limits the impact to monitoring applications only. 421// 422static char* get_user_name(int vmid) { 423 424 // A fast implementation is not provided at this time. It's possible 425 // to provide a fast process id to user name mapping function using 426 // the win32 apis, but the default ACL for the process object only 427 // allows processes with the same owner SID to acquire the process 428 // handle (via OpenProcess(PROCESS_QUERY_INFORMATION)). It's possible 429 // to have the JVM change the ACL for the process object to allow arbitrary 430 // users to access the process handle and the process security token. 431 // The security ramifications need to be studied before providing this 432 // mechanism. 433 // 434 return get_user_name_slow(vmid); 435} 436 437// return the name of the shared memory file mapping object for the 438// named shared memory region for the given user name and vmid. 439// 440// The file mapping object's name is not the file name. It is a name 441// in a separate name space. 442// 443// the caller is expected to free the allocated memory. 444// 445static char *get_sharedmem_objectname(const char* user, int vmid) { 446 447 // construct file mapping object's name, add 3 for two '_' and a 448 // null terminator. 449 int nbytes = (int)strlen(PERFDATA_NAME) + (int)strlen(user) + 3; 450 451 // the id is converted to an unsigned value here because win32 allows 452 // negative process ids. However, OpenFileMapping API complains 453 // about a name containing a '-' characters. 454 // 455 nbytes += UINT_CHARS; 456 char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal); 457 _snprintf(name, nbytes, "%s_%s_%u", PERFDATA_NAME, user, vmid); 458 459 return name; 460} 461 462// return the file name of the backing store file for the named 463// shared memory region for the given user name and vmid. 464// 465// the caller is expected to free the allocated memory. 466// 467static char* get_sharedmem_filename(const char* dirname, int vmid) { 468 469 // add 2 for the file separator and a null terminator. 470 size_t nbytes = strlen(dirname) + UINT_CHARS + 2; 471 472 char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal); 473 _snprintf(name, nbytes, "%s\\%d", dirname, vmid); 474 475 return name; 476} 477 478// remove file 479// 480// this method removes the file with the given file name. 481// 482// Note: if the indicated file is on an SMB network file system, this 483// method may be unsuccessful in removing the file. 484// 485static void remove_file(const char* dirname, const char* filename) { 486 487 size_t nbytes = strlen(dirname) + strlen(filename) + 2; 488 char* path = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal); 489 490 strcpy(path, dirname); 491 strcat(path, "\\"); 492 strcat(path, filename); 493 494 if (::unlink(path) == OS_ERR) { 495 if (PrintMiscellaneous && Verbose) { 496 if (errno != ENOENT) { 497 warning("Could not unlink shared memory backing" 498 " store file %s : %s\n", path, strerror(errno)); 499 } 500 } 501 } 502 503 FREE_C_HEAP_ARRAY(char, path, mtInternal); 504} 505 506// returns true if the process represented by pid is alive, otherwise 507// returns false. the validity of the result is only accurate if the 508// target process is owned by the same principal that owns this process. 509// this method should not be used if to test the status of an otherwise 510// arbitrary process unless it is know that this process has the appropriate 511// privileges to guarantee a result valid. 512// 513static bool is_alive(int pid) { 514 515 HANDLE ph = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid); 516 if (ph == NULL) { 517 // the process does not exist. 518 if (PrintMiscellaneous && Verbose) { 519 DWORD lastError = GetLastError(); 520 if (lastError != ERROR_INVALID_PARAMETER) { 521 warning("OpenProcess failed: %d\n", GetLastError()); 522 } 523 } 524 return false; 525 } 526 527 DWORD exit_status; 528 if (!GetExitCodeProcess(ph, &exit_status)) { 529 if (PrintMiscellaneous && Verbose) { 530 warning("GetExitCodeProcess failed: %d\n", GetLastError()); 531 } 532 CloseHandle(ph); 533 return false; 534 } 535 536 CloseHandle(ph); 537 return (exit_status == STILL_ACTIVE) ? true : false; 538} 539 540// check if the file system is considered secure for the backing store files 541// 542static bool is_filesystem_secure(const char* path) { 543 544 char root_path[MAX_PATH]; 545 char fs_type[MAX_PATH]; 546 547 if (PerfBypassFileSystemCheck) { 548 if (PrintMiscellaneous && Verbose) { 549 warning("bypassing file system criteria checks for %s\n", path); 550 } 551 return true; 552 } 553 554 char* first_colon = strchr((char *)path, ':'); 555 if (first_colon == NULL) { 556 if (PrintMiscellaneous && Verbose) { 557 warning("expected device specifier in path: %s\n", path); 558 } 559 return false; 560 } 561 562 size_t len = (size_t)(first_colon - path); 563 assert(len + 2 <= MAX_PATH, "unexpected device specifier length"); 564 strncpy(root_path, path, len + 1); 565 root_path[len + 1] = '\\'; 566 root_path[len + 2] = '\0'; 567 568 // check that we have something like "C:\" or "AA:\" 569 assert(strlen(root_path) >= 3, "device specifier too short"); 570 assert(strchr(root_path, ':') != NULL, "bad device specifier format"); 571 assert(strchr(root_path, '\\') != NULL, "bad device specifier format"); 572 573 DWORD maxpath; 574 DWORD flags; 575 576 if (!GetVolumeInformation(root_path, NULL, 0, NULL, &maxpath, 577 &flags, fs_type, MAX_PATH)) { 578 // we can't get information about the volume, so assume unsafe. 579 if (PrintMiscellaneous && Verbose) { 580 warning("could not get device information for %s: " 581 " path = %s: lasterror = %d\n", 582 root_path, path, GetLastError()); 583 } 584 return false; 585 } 586 587 if ((flags & FS_PERSISTENT_ACLS) == 0) { 588 // file system doesn't support ACLs, declare file system unsafe 589 if (PrintMiscellaneous && Verbose) { 590 warning("file system type %s on device %s does not support" 591 " ACLs\n", fs_type, root_path); 592 } 593 return false; 594 } 595 596 if ((flags & FS_VOL_IS_COMPRESSED) != 0) { 597 // file system is compressed, declare file system unsafe 598 if (PrintMiscellaneous && Verbose) { 599 warning("file system type %s on device %s is compressed\n", 600 fs_type, root_path); 601 } 602 return false; 603 } 604 605 return true; 606} 607 608// cleanup stale shared memory resources 609// 610// This method attempts to remove all stale shared memory files in 611// the named user temporary directory. It scans the named directory 612// for files matching the pattern ^$[0-9]*$. For each file found, the 613// process id is extracted from the file name and a test is run to 614// determine if the process is alive. If the process is not alive, 615// any stale file resources are removed. 616// 617static void cleanup_sharedmem_resources(const char* dirname) { 618 619 // open the user temp directory 620 DIR* dirp = os::opendir(dirname); 621 622 if (dirp == NULL) { 623 // directory doesn't exist, so there is nothing to cleanup 624 return; 625 } 626 627 if (!is_directory_secure(dirname)) { 628 // the directory is not secure, don't attempt any cleanup 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 char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname), mtInternal); 642 errno = 0; 643 while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) { 644 645 int pid = filename_to_pid(entry->d_name); 646 647 if (pid == 0) { 648 649 if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) { 650 651 // attempt to remove all unexpected files, except "." and ".." 652 remove_file(dirname, entry->d_name); 653 } 654 655 errno = 0; 656 continue; 657 } 658 659 // we now have a file name that converts to a valid integer 660 // that could represent a process id . if this process id 661 // matches the current process id or the process is not running, 662 // then remove the stale file resources. 663 // 664 // process liveness is detected by checking the exit status 665 // of the process. if the process id is valid and the exit status 666 // indicates that it is still running, the file file resources 667 // are not removed. If the process id is invalid, or if we don't 668 // have permissions to check the process status, or if the process 669 // id is valid and the process has terminated, the the file resources 670 // are assumed to be stale and are removed. 671 // 672 if (pid == os::current_process_id() || !is_alive(pid)) { 673 674 // we can only remove the file resources. Any mapped views 675 // of the file can only be unmapped by the processes that 676 // opened those views and the file mapping object will not 677 // get removed until all views are unmapped. 678 // 679 remove_file(dirname, entry->d_name); 680 } 681 errno = 0; 682 } 683 os::closedir(dirp); 684 FREE_C_HEAP_ARRAY(char, dbuf, mtInternal); 685} 686 687// create a file mapping object with the requested name, and size 688// from the file represented by the given Handle object 689// 690static HANDLE create_file_mapping(const char* name, HANDLE fh, LPSECURITY_ATTRIBUTES fsa, size_t size) { 691 692 DWORD lowSize = (DWORD)size; 693 DWORD highSize = 0; 694 HANDLE fmh = NULL; 695 696 // Create a file mapping object with the given name. This function 697 // will grow the file to the specified size. 698 // 699 fmh = CreateFileMapping( 700 fh, /* HANDLE file handle for backing store */ 701 fsa, /* LPSECURITY_ATTRIBUTES Not inheritable */ 702 PAGE_READWRITE, /* DWORD protections */ 703 highSize, /* DWORD High word of max size */ 704 lowSize, /* DWORD Low word of max size */ 705 name); /* LPCTSTR name for object */ 706 707 if (fmh == NULL) { 708 if (PrintMiscellaneous && Verbose) { 709 warning("CreateFileMapping failed, lasterror = %d\n", GetLastError()); 710 } 711 return NULL; 712 } 713 714 if (GetLastError() == ERROR_ALREADY_EXISTS) { 715 716 // a stale file mapping object was encountered. This object may be 717 // owned by this or some other user and cannot be removed until 718 // the other processes either exit or close their mapping objects 719 // and/or mapped views of this mapping object. 720 // 721 if (PrintMiscellaneous && Verbose) { 722 warning("file mapping already exists, lasterror = %d\n", GetLastError()); 723 } 724 725 CloseHandle(fmh); 726 return NULL; 727 } 728 729 return fmh; 730} 731 732 733// method to free the given security descriptor and the contained 734// access control list. 735// 736static void free_security_desc(PSECURITY_DESCRIPTOR pSD) { 737 738 BOOL success, exists, isdefault; 739 PACL pACL; 740 741 if (pSD != NULL) { 742 743 // get the access control list from the security descriptor 744 success = GetSecurityDescriptorDacl(pSD, &exists, &pACL, &isdefault); 745 746 // if an ACL existed and it was not a default acl, then it must 747 // be an ACL we enlisted. free the resources. 748 // 749 if (success && exists && pACL != NULL && !isdefault) { 750 FREE_C_HEAP_ARRAY(char, pACL, mtInternal); 751 } 752 753 // free the security descriptor 754 FREE_C_HEAP_ARRAY(char, pSD, mtInternal); 755 } 756} 757 758// method to free up a security attributes structure and any 759// contained security descriptors and ACL 760// 761static void free_security_attr(LPSECURITY_ATTRIBUTES lpSA) { 762 763 if (lpSA != NULL) { 764 // free the contained security descriptor and the ACL 765 free_security_desc(lpSA->lpSecurityDescriptor); 766 lpSA->lpSecurityDescriptor = NULL; 767 768 // free the security attributes structure 769 FREE_C_HEAP_ARRAY(char, lpSA, mtInternal); 770 } 771} 772 773// get the user SID for the process indicated by the process handle 774// 775static PSID get_user_sid(HANDLE hProcess) { 776 777 HANDLE hAccessToken; 778 PTOKEN_USER token_buf = NULL; 779 DWORD rsize = 0; 780 781 if (hProcess == NULL) { 782 return NULL; 783 } 784 785 // get the process token 786 if (!OpenProcessToken(hProcess, TOKEN_READ, &hAccessToken)) { 787 if (PrintMiscellaneous && Verbose) { 788 warning("OpenProcessToken failure: lasterror = %d \n", GetLastError()); 789 } 790 return NULL; 791 } 792 793 // determine the size of the token structured needed to retrieve 794 // the user token information from the access token. 795 // 796 if (!GetTokenInformation(hAccessToken, TokenUser, NULL, rsize, &rsize)) { 797 DWORD lasterror = GetLastError(); 798 if (lasterror != ERROR_INSUFFICIENT_BUFFER) { 799 if (PrintMiscellaneous && Verbose) { 800 warning("GetTokenInformation failure: lasterror = %d," 801 " rsize = %d\n", lasterror, rsize); 802 } 803 CloseHandle(hAccessToken); 804 return NULL; 805 } 806 } 807 808 token_buf = (PTOKEN_USER) NEW_C_HEAP_ARRAY(char, rsize, mtInternal); 809 810 // get the user token information 811 if (!GetTokenInformation(hAccessToken, TokenUser, token_buf, rsize, &rsize)) { 812 if (PrintMiscellaneous && Verbose) { 813 warning("GetTokenInformation failure: lasterror = %d," 814 " rsize = %d\n", GetLastError(), rsize); 815 } 816 FREE_C_HEAP_ARRAY(char, token_buf, mtInternal); 817 CloseHandle(hAccessToken); 818 return NULL; 819 } 820 821 DWORD nbytes = GetLengthSid(token_buf->User.Sid); 822 PSID pSID = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal); 823 824 if (!CopySid(nbytes, pSID, token_buf->User.Sid)) { 825 if (PrintMiscellaneous && Verbose) { 826 warning("GetTokenInformation failure: lasterror = %d," 827 " rsize = %d\n", GetLastError(), rsize); 828 } 829 FREE_C_HEAP_ARRAY(char, token_buf, mtInternal); 830 FREE_C_HEAP_ARRAY(char, pSID, mtInternal); 831 CloseHandle(hAccessToken); 832 return NULL; 833 } 834 835 // close the access token. 836 CloseHandle(hAccessToken); 837 FREE_C_HEAP_ARRAY(char, token_buf, mtInternal); 838 839 return pSID; 840} 841 842// structure used to consolidate access control entry information 843// 844typedef struct ace_data { 845 PSID pSid; // SID of the ACE 846 DWORD mask; // mask for the ACE 847} ace_data_t; 848 849 850// method to add an allow access control entry with the access rights 851// indicated in mask for the principal indicated in SID to the given 852// security descriptor. Much of the DACL handling was adapted from 853// the example provided here: 854// http://support.microsoft.com/kb/102102/EN-US/ 855// 856 857static bool add_allow_aces(PSECURITY_DESCRIPTOR pSD, 858 ace_data_t aces[], int ace_count) { 859 PACL newACL = NULL; 860 PACL oldACL = NULL; 861 862 if (pSD == NULL) { 863 return false; 864 } 865 866 BOOL exists, isdefault; 867 868 // retrieve any existing access control list. 869 if (!GetSecurityDescriptorDacl(pSD, &exists, &oldACL, &isdefault)) { 870 if (PrintMiscellaneous && Verbose) { 871 warning("GetSecurityDescriptor failure: lasterror = %d \n", 872 GetLastError()); 873 } 874 return false; 875 } 876 877 // get the size of the DACL 878 ACL_SIZE_INFORMATION aclinfo; 879 880 // GetSecurityDescriptorDacl may return true value for exists (lpbDaclPresent) 881 // while oldACL is NULL for some case. 882 if (oldACL == NULL) { 883 exists = FALSE; 884 } 885 886 if (exists) { 887 if (!GetAclInformation(oldACL, &aclinfo, 888 sizeof(ACL_SIZE_INFORMATION), 889 AclSizeInformation)) { 890 if (PrintMiscellaneous && Verbose) { 891 warning("GetAclInformation failure: lasterror = %d \n", GetLastError()); 892 return false; 893 } 894 } 895 } else { 896 aclinfo.AceCount = 0; // assume NULL DACL 897 aclinfo.AclBytesFree = 0; 898 aclinfo.AclBytesInUse = sizeof(ACL); 899 } 900 901 // compute the size needed for the new ACL 902 // initial size of ACL is sum of the following: 903 // * size of ACL structure. 904 // * size of each ACE structure that ACL is to contain minus the sid 905 // sidStart member (DWORD) of the ACE. 906 // * length of the SID that each ACE is to contain. 907 DWORD newACLsize = aclinfo.AclBytesInUse + 908 (sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD)) * ace_count; 909 for (int i = 0; i < ace_count; i++) { 910 assert(aces[i].pSid != 0, "pSid should not be 0"); 911 newACLsize += GetLengthSid(aces[i].pSid); 912 } 913 914 // create the new ACL 915 newACL = (PACL) NEW_C_HEAP_ARRAY(char, newACLsize, mtInternal); 916 917 if (!InitializeAcl(newACL, newACLsize, ACL_REVISION)) { 918 if (PrintMiscellaneous && Verbose) { 919 warning("InitializeAcl failure: lasterror = %d \n", GetLastError()); 920 } 921 FREE_C_HEAP_ARRAY(char, newACL, mtInternal); 922 return false; 923 } 924 925 unsigned int ace_index = 0; 926 // copy any existing ACEs from the old ACL (if any) to the new ACL. 927 if (aclinfo.AceCount != 0) { 928 while (ace_index < aclinfo.AceCount) { 929 LPVOID ace; 930 if (!GetAce(oldACL, ace_index, &ace)) { 931 if (PrintMiscellaneous && Verbose) { 932 warning("InitializeAcl failure: lasterror = %d \n", GetLastError()); 933 } 934 FREE_C_HEAP_ARRAY(char, newACL, mtInternal); 935 return false; 936 } 937 if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceFlags && INHERITED_ACE) { 938 // this is an inherited, allowed ACE; break from loop so we can 939 // add the new access allowed, non-inherited ACE in the correct 940 // position, immediately following all non-inherited ACEs. 941 break; 942 } 943 944 // determine if the SID of this ACE matches any of the SIDs 945 // for which we plan to set ACEs. 946 int matches = 0; 947 for (int i = 0; i < ace_count; i++) { 948 if (EqualSid(aces[i].pSid, &(((ACCESS_ALLOWED_ACE *)ace)->SidStart))) { 949 matches++; 950 break; 951 } 952 } 953 954 // if there are no SID matches, then add this existing ACE to the new ACL 955 if (matches == 0) { 956 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace, 957 ((PACE_HEADER)ace)->AceSize)) { 958 if (PrintMiscellaneous && Verbose) { 959 warning("AddAce failure: lasterror = %d \n", GetLastError()); 960 } 961 FREE_C_HEAP_ARRAY(char, newACL, mtInternal); 962 return false; 963 } 964 } 965 ace_index++; 966 } 967 } 968 969 // add the passed-in access control entries to the new ACL 970 for (int i = 0; i < ace_count; i++) { 971 if (!AddAccessAllowedAce(newACL, ACL_REVISION, 972 aces[i].mask, aces[i].pSid)) { 973 if (PrintMiscellaneous && Verbose) { 974 warning("AddAccessAllowedAce failure: lasterror = %d \n", 975 GetLastError()); 976 } 977 FREE_C_HEAP_ARRAY(char, newACL, mtInternal); 978 return false; 979 } 980 } 981 982 // now copy the rest of the inherited ACEs from the old ACL 983 if (aclinfo.AceCount != 0) { 984 // picking up at ace_index, where we left off in the 985 // previous ace_index loop 986 while (ace_index < aclinfo.AceCount) { 987 LPVOID ace; 988 if (!GetAce(oldACL, ace_index, &ace)) { 989 if (PrintMiscellaneous && Verbose) { 990 warning("InitializeAcl failure: lasterror = %d \n", GetLastError()); 991 } 992 FREE_C_HEAP_ARRAY(char, newACL, mtInternal); 993 return false; 994 } 995 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace, 996 ((PACE_HEADER)ace)->AceSize)) { 997 if (PrintMiscellaneous && Verbose) { 998 warning("AddAce failure: lasterror = %d \n", GetLastError()); 999 } 1000 FREE_C_HEAP_ARRAY(char, newACL, mtInternal); 1001 return false; 1002 } 1003 ace_index++; 1004 } 1005 } 1006 1007 // add the new ACL to the security descriptor. 1008 if (!SetSecurityDescriptorDacl(pSD, TRUE, newACL, FALSE)) { 1009 if (PrintMiscellaneous && Verbose) { 1010 warning("SetSecurityDescriptorDacl failure:" 1011 " lasterror = %d \n", GetLastError()); 1012 } 1013 FREE_C_HEAP_ARRAY(char, newACL, mtInternal); 1014 return false; 1015 } 1016 1017 // if running on windows 2000 or later, set the automatic inheritance 1018 // control flags. 1019 SetSecurityDescriptorControlFnPtr _SetSecurityDescriptorControl; 1020 _SetSecurityDescriptorControl = (SetSecurityDescriptorControlFnPtr) 1021 GetProcAddress(GetModuleHandle(TEXT("advapi32.dll")), 1022 "SetSecurityDescriptorControl"); 1023 1024 if (_SetSecurityDescriptorControl != NULL) { 1025 // We do not want to further propagate inherited DACLs, so making them 1026 // protected prevents that. 1027 if (!_SetSecurityDescriptorControl(pSD, SE_DACL_PROTECTED, 1028 SE_DACL_PROTECTED)) { 1029 if (PrintMiscellaneous && Verbose) { 1030 warning("SetSecurityDescriptorControl failure:" 1031 " lasterror = %d \n", GetLastError()); 1032 } 1033 FREE_C_HEAP_ARRAY(char, newACL, mtInternal); 1034 return false; 1035 } 1036 } 1037 // Note, the security descriptor maintains a reference to the newACL, not 1038 // a copy of it. Therefore, the newACL is not freed here. It is freed when 1039 // the security descriptor containing its reference is freed. 1040 // 1041 return true; 1042} 1043 1044// method to create a security attributes structure, which contains a 1045// security descriptor and an access control list comprised of 0 or more 1046// access control entries. The method take an array of ace_data structures 1047// that indicate the ACE to be added to the security descriptor. 1048// 1049// the caller must free the resources associated with the security 1050// attributes structure created by this method by calling the 1051// free_security_attr() method. 1052// 1053static LPSECURITY_ATTRIBUTES make_security_attr(ace_data_t aces[], int count) { 1054 1055 // allocate space for a security descriptor 1056 PSECURITY_DESCRIPTOR pSD = (PSECURITY_DESCRIPTOR) 1057 NEW_C_HEAP_ARRAY(char, SECURITY_DESCRIPTOR_MIN_LENGTH, mtInternal); 1058 1059 // initialize the security descriptor 1060 if (!InitializeSecurityDescriptor(pSD, SECURITY_DESCRIPTOR_REVISION)) { 1061 if (PrintMiscellaneous && Verbose) { 1062 warning("InitializeSecurityDescriptor failure: " 1063 "lasterror = %d \n", GetLastError()); 1064 } 1065 free_security_desc(pSD); 1066 return NULL; 1067 } 1068 1069 // add the access control entries 1070 if (!add_allow_aces(pSD, aces, count)) { 1071 free_security_desc(pSD); 1072 return NULL; 1073 } 1074 1075 // allocate and initialize the security attributes structure and 1076 // return it to the caller. 1077 // 1078 LPSECURITY_ATTRIBUTES lpSA = (LPSECURITY_ATTRIBUTES) 1079 NEW_C_HEAP_ARRAY(char, sizeof(SECURITY_ATTRIBUTES), mtInternal); 1080 lpSA->nLength = sizeof(SECURITY_ATTRIBUTES); 1081 lpSA->lpSecurityDescriptor = pSD; 1082 lpSA->bInheritHandle = FALSE; 1083 1084 return(lpSA); 1085} 1086 1087// method to create a security attributes structure with a restrictive 1088// access control list that creates a set access rights for the user/owner 1089// of the securable object and a separate set access rights for everyone else. 1090// also provides for full access rights for the administrator group. 1091// 1092// the caller must free the resources associated with the security 1093// attributes structure created by this method by calling the 1094// free_security_attr() method. 1095// 1096 1097static LPSECURITY_ATTRIBUTES make_user_everybody_admin_security_attr( 1098 DWORD umask, DWORD emask, DWORD amask) { 1099 1100 ace_data_t aces[3]; 1101 1102 // initialize the user ace data 1103 aces[0].pSid = get_user_sid(GetCurrentProcess()); 1104 aces[0].mask = umask; 1105 1106 if (aces[0].pSid == 0) 1107 return NULL; 1108 1109 // get the well known SID for BUILTIN\Administrators 1110 PSID administratorsSid = NULL; 1111 SID_IDENTIFIER_AUTHORITY SIDAuthAdministrators = SECURITY_NT_AUTHORITY; 1112 1113 if (!AllocateAndInitializeSid( &SIDAuthAdministrators, 2, 1114 SECURITY_BUILTIN_DOMAIN_RID, 1115 DOMAIN_ALIAS_RID_ADMINS, 1116 0, 0, 0, 0, 0, 0, &administratorsSid)) { 1117 1118 if (PrintMiscellaneous && Verbose) { 1119 warning("AllocateAndInitializeSid failure: " 1120 "lasterror = %d \n", GetLastError()); 1121 } 1122 return NULL; 1123 } 1124 1125 // initialize the ace data for administrator group 1126 aces[1].pSid = administratorsSid; 1127 aces[1].mask = amask; 1128 1129 // get the well known SID for the universal Everybody 1130 PSID everybodySid = NULL; 1131 SID_IDENTIFIER_AUTHORITY SIDAuthEverybody = SECURITY_WORLD_SID_AUTHORITY; 1132 1133 if (!AllocateAndInitializeSid( &SIDAuthEverybody, 1, SECURITY_WORLD_RID, 1134 0, 0, 0, 0, 0, 0, 0, &everybodySid)) { 1135 1136 if (PrintMiscellaneous && Verbose) { 1137 warning("AllocateAndInitializeSid failure: " 1138 "lasterror = %d \n", GetLastError()); 1139 } 1140 return NULL; 1141 } 1142 1143 // initialize the ace data for everybody else. 1144 aces[2].pSid = everybodySid; 1145 aces[2].mask = emask; 1146 1147 // create a security attributes structure with access control 1148 // entries as initialized above. 1149 LPSECURITY_ATTRIBUTES lpSA = make_security_attr(aces, 3); 1150 FREE_C_HEAP_ARRAY(char, aces[0].pSid, mtInternal); 1151 FreeSid(everybodySid); 1152 FreeSid(administratorsSid); 1153 return(lpSA); 1154} 1155 1156 1157// method to create the security attributes structure for restricting 1158// access to the user temporary directory. 1159// 1160// the caller must free the resources associated with the security 1161// attributes structure created by this method by calling the 1162// free_security_attr() method. 1163// 1164static LPSECURITY_ATTRIBUTES make_tmpdir_security_attr() { 1165 1166 // create full access rights for the user/owner of the directory 1167 // and read-only access rights for everybody else. This is 1168 // effectively equivalent to UNIX 755 permissions on a directory. 1169 // 1170 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_ALL_ACCESS; 1171 DWORD emask = GENERIC_READ | FILE_LIST_DIRECTORY | FILE_TRAVERSE; 1172 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS; 1173 1174 return make_user_everybody_admin_security_attr(umask, emask, amask); 1175} 1176 1177// method to create the security attributes structure for restricting 1178// access to the shared memory backing store file. 1179// 1180// the caller must free the resources associated with the security 1181// attributes structure created by this method by calling the 1182// free_security_attr() method. 1183// 1184static LPSECURITY_ATTRIBUTES make_file_security_attr() { 1185 1186 // create extensive access rights for the user/owner of the file 1187 // and attribute read-only access rights for everybody else. This 1188 // is effectively equivalent to UNIX 600 permissions on a file. 1189 // 1190 DWORD umask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS; 1191 DWORD emask = STANDARD_RIGHTS_READ | FILE_READ_ATTRIBUTES | 1192 FILE_READ_EA | FILE_LIST_DIRECTORY | FILE_TRAVERSE; 1193 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS; 1194 1195 return make_user_everybody_admin_security_attr(umask, emask, amask); 1196} 1197 1198// method to create the security attributes structure for restricting 1199// access to the name shared memory file mapping object. 1200// 1201// the caller must free the resources associated with the security 1202// attributes structure created by this method by calling the 1203// free_security_attr() method. 1204// 1205static LPSECURITY_ATTRIBUTES make_smo_security_attr() { 1206 1207 // create extensive access rights for the user/owner of the shared 1208 // memory object and attribute read-only access rights for everybody 1209 // else. This is effectively equivalent to UNIX 600 permissions on 1210 // on the shared memory object. 1211 // 1212 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_MAP_ALL_ACCESS; 1213 DWORD emask = STANDARD_RIGHTS_READ; // attributes only 1214 DWORD amask = STANDARD_RIGHTS_ALL | FILE_MAP_ALL_ACCESS; 1215 1216 return make_user_everybody_admin_security_attr(umask, emask, amask); 1217} 1218 1219// make the user specific temporary directory 1220// 1221static bool make_user_tmp_dir(const char* dirname) { 1222 1223 1224 LPSECURITY_ATTRIBUTES pDirSA = make_tmpdir_security_attr(); 1225 if (pDirSA == NULL) { 1226 return false; 1227 } 1228 1229 1230 // create the directory with the given security attributes 1231 if (!CreateDirectory(dirname, pDirSA)) { 1232 DWORD lasterror = GetLastError(); 1233 if (lasterror == ERROR_ALREADY_EXISTS) { 1234 // The directory already exists and was probably created by another 1235 // JVM instance. However, this could also be the result of a 1236 // deliberate symlink. Verify that the existing directory is safe. 1237 // 1238 if (!is_directory_secure(dirname)) { 1239 // directory is not secure 1240 if (PrintMiscellaneous && Verbose) { 1241 warning("%s directory is insecure\n", dirname); 1242 } 1243 return false; 1244 } 1245 // The administrator should be able to delete this directory. 1246 // But the directory created by previous version of JVM may not 1247 // have permission for administrators to delete this directory. 1248 // So add full permission to the administrator. Also setting new 1249 // DACLs might fix the corrupted the DACLs. 1250 SECURITY_INFORMATION secInfo = DACL_SECURITY_INFORMATION; 1251 if (!SetFileSecurity(dirname, secInfo, pDirSA->lpSecurityDescriptor)) { 1252 if (PrintMiscellaneous && Verbose) { 1253 lasterror = GetLastError(); 1254 warning("SetFileSecurity failed for %s directory. lasterror %d \n", 1255 dirname, lasterror); 1256 } 1257 } 1258 } 1259 else { 1260 if (PrintMiscellaneous && Verbose) { 1261 warning("CreateDirectory failed: %d\n", GetLastError()); 1262 } 1263 return false; 1264 } 1265 } 1266 1267 // free the security attributes structure 1268 free_security_attr(pDirSA); 1269 1270 return true; 1271} 1272 1273// create the shared memory resources 1274// 1275// This function creates the shared memory resources. This includes 1276// the backing store file and the file mapping shared memory object. 1277// 1278static HANDLE create_sharedmem_resources(const char* dirname, const char* filename, const char* objectname, size_t size) { 1279 1280 HANDLE fh = INVALID_HANDLE_VALUE; 1281 HANDLE fmh = NULL; 1282 1283 1284 // create the security attributes for the backing store file 1285 LPSECURITY_ATTRIBUTES lpFileSA = make_file_security_attr(); 1286 if (lpFileSA == NULL) { 1287 return NULL; 1288 } 1289 1290 // create the security attributes for the shared memory object 1291 LPSECURITY_ATTRIBUTES lpSmoSA = make_smo_security_attr(); 1292 if (lpSmoSA == NULL) { 1293 free_security_attr(lpFileSA); 1294 return NULL; 1295 } 1296 1297 // create the user temporary directory 1298 if (!make_user_tmp_dir(dirname)) { 1299 // could not make/find the directory or the found directory 1300 // was not secure 1301 return NULL; 1302 } 1303 1304 // Create the file - the FILE_FLAG_DELETE_ON_CLOSE flag allows the 1305 // file to be deleted by the last process that closes its handle to 1306 // the file. This is important as the apis do not allow a terminating 1307 // JVM being monitored by another process to remove the file name. 1308 // 1309 // the FILE_SHARE_DELETE share mode is valid only in winnt 1310 // 1311 fh = CreateFile( 1312 filename, /* LPCTSTR file name */ 1313 1314 GENERIC_READ|GENERIC_WRITE, /* DWORD desired access */ 1315 1316 (os::win32::is_nt() ? FILE_SHARE_DELETE : 0)| 1317 FILE_SHARE_READ, /* DWORD share mode, future READONLY 1318 * open operations allowed 1319 */ 1320 lpFileSA, /* LPSECURITY security attributes */ 1321 CREATE_ALWAYS, /* DWORD creation disposition 1322 * create file, if it already 1323 * exists, overwrite it. 1324 */ 1325 FILE_FLAG_DELETE_ON_CLOSE, /* DWORD flags and attributes */ 1326 1327 NULL); /* HANDLE template file access */ 1328 1329 free_security_attr(lpFileSA); 1330 1331 if (fh == INVALID_HANDLE_VALUE) { 1332 DWORD lasterror = GetLastError(); 1333 if (PrintMiscellaneous && Verbose) { 1334 warning("could not create file %s: %d\n", filename, lasterror); 1335 } 1336 return NULL; 1337 } 1338 1339 // try to create the file mapping 1340 fmh = create_file_mapping(objectname, fh, lpSmoSA, size); 1341 1342 free_security_attr(lpSmoSA); 1343 1344 if (fmh == NULL) { 1345 // closing the file handle here will decrement the reference count 1346 // on the file. When all processes accessing the file close their 1347 // handle to it, the reference count will decrement to 0 and the 1348 // OS will delete the file. These semantics are requested by the 1349 // FILE_FLAG_DELETE_ON_CLOSE flag in CreateFile call above. 1350 CloseHandle(fh); 1351 fh = NULL; 1352 return NULL; 1353 } else { 1354 // We created the file mapping, but rarely the size of the 1355 // backing store file is reported as zero (0) which can cause 1356 // failures when trying to use the hsperfdata file. 1357 struct stat statbuf; 1358 int ret_code = ::stat(filename, &statbuf); 1359 if (ret_code == OS_ERR) { 1360 if (PrintMiscellaneous && Verbose) { 1361 warning("Could not get status information from file %s: %s\n", 1362 filename, strerror(errno)); 1363 } 1364 CloseHandle(fmh); 1365 CloseHandle(fh); 1366 fh = NULL; 1367 fmh = NULL; 1368 return NULL; 1369 } 1370 1371 // We could always call FlushFileBuffers() but the Microsoft 1372 // docs indicate that it is considered expensive so we only 1373 // call it when we observe the size as zero (0). 1374 if (statbuf.st_size == 0 && FlushFileBuffers(fh) != TRUE) { 1375 DWORD lasterror = GetLastError(); 1376 if (PrintMiscellaneous && Verbose) { 1377 warning("could not flush file %s: %d\n", filename, lasterror); 1378 } 1379 CloseHandle(fmh); 1380 CloseHandle(fh); 1381 fh = NULL; 1382 fmh = NULL; 1383 return NULL; 1384 } 1385 } 1386 1387 // the file has been successfully created and the file mapping 1388 // object has been created. 1389 sharedmem_fileHandle = fh; 1390 sharedmem_fileName = strdup(filename); 1391 1392 return fmh; 1393} 1394 1395// open the shared memory object for the given vmid. 1396// 1397static HANDLE open_sharedmem_object(const char* objectname, DWORD ofm_access, TRAPS) { 1398 1399 HANDLE fmh; 1400 1401 // open the file mapping with the requested mode 1402 fmh = OpenFileMapping( 1403 ofm_access, /* DWORD access mode */ 1404 FALSE, /* BOOL inherit flag - Do not allow inherit */ 1405 objectname); /* name for object */ 1406 1407 if (fmh == NULL) { 1408 if (PrintMiscellaneous && Verbose) { 1409 warning("OpenFileMapping failed for shared memory object %s:" 1410 " lasterror = %d\n", objectname, GetLastError()); 1411 } 1412 THROW_MSG_(vmSymbols::java_lang_Exception(), 1413 "Could not open PerfMemory", INVALID_HANDLE_VALUE); 1414 } 1415 1416 return fmh;; 1417} 1418 1419// create a named shared memory region 1420// 1421// On Win32, a named shared memory object has a name space that 1422// is independent of the file system name space. Shared memory object, 1423// or more precisely, file mapping objects, provide no mechanism to 1424// inquire the size of the memory region. There is also no api to 1425// enumerate the memory regions for various processes. 1426// 1427// This implementation utilizes the shared memory name space in parallel 1428// with the file system name space. This allows us to determine the 1429// size of the shared memory region from the size of the file and it 1430// allows us to provide a common, file system based name space for 1431// shared memory across platforms. 1432// 1433static char* mapping_create_shared(size_t size) { 1434 1435 void *mapAddress; 1436 int vmid = os::current_process_id(); 1437 1438 // get the name of the user associated with this process 1439 char* user = get_user_name(); 1440 1441 if (user == NULL) { 1442 return NULL; 1443 } 1444 1445 // construct the name of the user specific temporary directory 1446 char* dirname = get_user_tmp_dir(user); 1447 1448 // check that the file system is secure - i.e. it supports ACLs. 1449 if (!is_filesystem_secure(dirname)) { 1450 return NULL; 1451 } 1452 1453 // create the names of the backing store files and for the 1454 // share memory object. 1455 // 1456 char* filename = get_sharedmem_filename(dirname, vmid); 1457 char* objectname = get_sharedmem_objectname(user, vmid); 1458 1459 // cleanup any stale shared memory resources 1460 cleanup_sharedmem_resources(dirname); 1461 1462 assert(((size != 0) && (size % os::vm_page_size() == 0)), 1463 "unexpected PerfMemry region size"); 1464 1465 FREE_C_HEAP_ARRAY(char, user, mtInternal); 1466 1467 // create the shared memory resources 1468 sharedmem_fileMapHandle = 1469 create_sharedmem_resources(dirname, filename, objectname, size); 1470 1471 FREE_C_HEAP_ARRAY(char, filename, mtInternal); 1472 FREE_C_HEAP_ARRAY(char, objectname, mtInternal); 1473 FREE_C_HEAP_ARRAY(char, dirname, mtInternal); 1474 1475 if (sharedmem_fileMapHandle == NULL) { 1476 return NULL; 1477 } 1478 1479 // map the file into the address space 1480 mapAddress = MapViewOfFile( 1481 sharedmem_fileMapHandle, /* HANDLE = file mapping object */ 1482 FILE_MAP_ALL_ACCESS, /* DWORD access flags */ 1483 0, /* DWORD High word of offset */ 1484 0, /* DWORD Low word of offset */ 1485 (DWORD)size); /* DWORD Number of bytes to map */ 1486 1487 if (mapAddress == NULL) { 1488 if (PrintMiscellaneous && Verbose) { 1489 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError()); 1490 } 1491 CloseHandle(sharedmem_fileMapHandle); 1492 sharedmem_fileMapHandle = NULL; 1493 return NULL; 1494 } 1495 1496 // clear the shared memory region 1497 (void)memset(mapAddress, '\0', size); 1498 1499 return (char*) mapAddress; 1500} 1501 1502// this method deletes the file mapping object. 1503// 1504static void delete_file_mapping(char* addr, size_t size) { 1505 1506 // cleanup the persistent shared memory resources. since DestroyJavaVM does 1507 // not support unloading of the JVM, unmapping of the memory resource is not 1508 // performed. The memory will be reclaimed by the OS upon termination of all 1509 // processes mapping the resource. The file mapping handle and the file 1510 // handle are closed here to expedite the remove of the file by the OS. The 1511 // file is not removed directly because it was created with 1512 // FILE_FLAG_DELETE_ON_CLOSE semantics and any attempt to remove it would 1513 // be unsuccessful. 1514 1515 // close the fileMapHandle. the file mapping will still be retained 1516 // by the OS as long as any other JVM processes has an open file mapping 1517 // handle or a mapped view of the file. 1518 // 1519 if (sharedmem_fileMapHandle != NULL) { 1520 CloseHandle(sharedmem_fileMapHandle); 1521 sharedmem_fileMapHandle = NULL; 1522 } 1523 1524 // close the file handle. This will decrement the reference count on the 1525 // backing store file. When the reference count decrements to 0, the OS 1526 // will delete the file. These semantics apply because the file was 1527 // created with the FILE_FLAG_DELETE_ON_CLOSE flag. 1528 // 1529 if (sharedmem_fileHandle != INVALID_HANDLE_VALUE) { 1530 CloseHandle(sharedmem_fileHandle); 1531 sharedmem_fileHandle = INVALID_HANDLE_VALUE; 1532 } 1533} 1534 1535// this method determines the size of the shared memory file 1536// 1537static size_t sharedmem_filesize(const char* filename, TRAPS) { 1538 1539 struct stat statbuf; 1540 1541 // get the file size 1542 // 1543 // on win95/98/me, _stat returns a file size of 0 bytes, but on 1544 // winnt/2k the appropriate file size is returned. support for 1545 // the sharable aspects of performance counters was abandonded 1546 // on the non-nt win32 platforms due to this and other api 1547 // inconsistencies 1548 // 1549 if (::stat(filename, &statbuf) == OS_ERR) { 1550 if (PrintMiscellaneous && Verbose) { 1551 warning("stat %s failed: %s\n", filename, strerror(errno)); 1552 } 1553 THROW_MSG_0(vmSymbols::java_io_IOException(), 1554 "Could not determine PerfMemory size"); 1555 } 1556 1557 if ((statbuf.st_size == 0) || (statbuf.st_size % os::vm_page_size() != 0)) { 1558 if (PrintMiscellaneous && Verbose) { 1559 warning("unexpected file size: size = " SIZE_FORMAT "\n", 1560 statbuf.st_size); 1561 } 1562 THROW_MSG_0(vmSymbols::java_lang_Exception(), 1563 "Invalid PerfMemory size"); 1564 } 1565 1566 return statbuf.st_size; 1567} 1568 1569// this method opens a file mapping object and maps the object 1570// into the address space of the process 1571// 1572static void open_file_mapping(const char* user, int vmid, 1573 PerfMemory::PerfMemoryMode mode, 1574 char** addrp, size_t* sizep, TRAPS) { 1575 1576 ResourceMark rm; 1577 1578 void *mapAddress = 0; 1579 size_t size; 1580 HANDLE fmh; 1581 DWORD ofm_access; 1582 DWORD mv_access; 1583 const char* luser = NULL; 1584 1585 if (mode == PerfMemory::PERF_MODE_RO) { 1586 ofm_access = FILE_MAP_READ; 1587 mv_access = FILE_MAP_READ; 1588 } 1589 else if (mode == PerfMemory::PERF_MODE_RW) { 1590#ifdef LATER 1591 ofm_access = FILE_MAP_READ | FILE_MAP_WRITE; 1592 mv_access = FILE_MAP_READ | FILE_MAP_WRITE; 1593#else 1594 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), 1595 "Unsupported access mode"); 1596#endif 1597 } 1598 else { 1599 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), 1600 "Illegal access mode"); 1601 } 1602 1603 // if a user name wasn't specified, then find the user name for 1604 // the owner of the target vm. 1605 if (user == NULL || strlen(user) == 0) { 1606 luser = get_user_name(vmid); 1607 } 1608 else { 1609 luser = user; 1610 } 1611 1612 if (luser == NULL) { 1613 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), 1614 "Could not map vmid to user name"); 1615 } 1616 1617 // get the names for the resources for the target vm 1618 char* dirname = get_user_tmp_dir(luser); 1619 1620 // since we don't follow symbolic links when creating the backing 1621 // store file, we also don't following them when attaching 1622 // 1623 if (!is_directory_secure(dirname)) { 1624 FREE_C_HEAP_ARRAY(char, dirname, mtInternal); 1625 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), 1626 "Process not found"); 1627 } 1628 1629 char* filename = get_sharedmem_filename(dirname, vmid); 1630 char* objectname = get_sharedmem_objectname(luser, vmid); 1631 1632 // copy heap memory to resource memory. the objectname and 1633 // filename are passed to methods that may throw exceptions. 1634 // using resource arrays for these names prevents the leaks 1635 // that would otherwise occur. 1636 // 1637 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1); 1638 char* robjectname = NEW_RESOURCE_ARRAY(char, strlen(objectname) + 1); 1639 strcpy(rfilename, filename); 1640 strcpy(robjectname, objectname); 1641 1642 // free the c heap resources that are no longer needed 1643 if (luser != user) FREE_C_HEAP_ARRAY(char, luser, mtInternal); 1644 FREE_C_HEAP_ARRAY(char, dirname, mtInternal); 1645 FREE_C_HEAP_ARRAY(char, filename, mtInternal); 1646 FREE_C_HEAP_ARRAY(char, objectname, mtInternal); 1647 1648 if (*sizep == 0) { 1649 size = sharedmem_filesize(rfilename, CHECK); 1650 assert(size != 0, "unexpected size"); 1651 } 1652 1653 // Open the file mapping object with the given name 1654 fmh = open_sharedmem_object(robjectname, ofm_access, CHECK); 1655 1656 assert(fmh != INVALID_HANDLE_VALUE, "unexpected handle value"); 1657 1658 // map the entire file into the address space 1659 mapAddress = MapViewOfFile( 1660 fmh, /* HANDLE Handle of file mapping object */ 1661 mv_access, /* DWORD access flags */ 1662 0, /* DWORD High word of offset */ 1663 0, /* DWORD Low word of offset */ 1664 size); /* DWORD Number of bytes to map */ 1665 1666 if (mapAddress == NULL) { 1667 if (PrintMiscellaneous && Verbose) { 1668 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError()); 1669 } 1670 CloseHandle(fmh); 1671 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(), 1672 "Could not map PerfMemory"); 1673 } 1674 1675 *addrp = (char*)mapAddress; 1676 *sizep = size; 1677 1678 // File mapping object can be closed at this time without 1679 // invalidating the mapped view of the file 1680 CloseHandle(fmh); 1681 1682 if (PerfTraceMemOps) { 1683 tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at " 1684 INTPTR_FORMAT "\n", size, vmid, mapAddress); 1685 } 1686} 1687 1688// this method unmaps the the mapped view of the the 1689// file mapping object. 1690// 1691static void remove_file_mapping(char* addr) { 1692 1693 // the file mapping object was closed in open_file_mapping() 1694 // after the file map view was created. We only need to 1695 // unmap the file view here. 1696 UnmapViewOfFile(addr); 1697} 1698 1699// create the PerfData memory region in shared memory. 1700static char* create_shared_memory(size_t size) { 1701 1702 return mapping_create_shared(size); 1703} 1704 1705// release a named, shared memory region 1706// 1707void delete_shared_memory(char* addr, size_t size) { 1708 1709 delete_file_mapping(addr, size); 1710} 1711 1712 1713 1714 1715// create the PerfData memory region 1716// 1717// This method creates the memory region used to store performance 1718// data for the JVM. The memory may be created in standard or 1719// shared memory. 1720// 1721void PerfMemory::create_memory_region(size_t size) { 1722 1723 if (PerfDisableSharedMem || !os::win32::is_nt()) { 1724 // do not share the memory for the performance data. 1725 PerfDisableSharedMem = true; 1726 _start = create_standard_memory(size); 1727 } 1728 else { 1729 _start = create_shared_memory(size); 1730 if (_start == NULL) { 1731 1732 // creation of the shared memory region failed, attempt 1733 // to create a contiguous, non-shared memory region instead. 1734 // 1735 if (PrintMiscellaneous && Verbose) { 1736 warning("Reverting to non-shared PerfMemory region.\n"); 1737 } 1738 PerfDisableSharedMem = true; 1739 _start = create_standard_memory(size); 1740 } 1741 } 1742 1743 if (_start != NULL) _capacity = size; 1744 1745} 1746 1747// delete the PerfData memory region 1748// 1749// This method deletes the memory region used to store performance 1750// data for the JVM. The memory region indicated by the <address, size> 1751// tuple will be inaccessible after a call to this method. 1752// 1753void PerfMemory::delete_memory_region() { 1754 1755 assert((start() != NULL && capacity() > 0), "verify proper state"); 1756 1757 // If user specifies PerfDataSaveFile, it will save the performance data 1758 // to the specified file name no matter whether PerfDataSaveToFile is specified 1759 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag 1760 // -XX:+PerfDataSaveToFile. 1761 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) { 1762 save_memory_to_file(start(), capacity()); 1763 } 1764 1765 if (PerfDisableSharedMem) { 1766 delete_standard_memory(start(), capacity()); 1767 } 1768 else { 1769 delete_shared_memory(start(), capacity()); 1770 } 1771} 1772 1773// attach to the PerfData memory region for another JVM 1774// 1775// This method returns an <address, size> tuple that points to 1776// a memory buffer that is kept reasonably synchronized with 1777// the PerfData memory region for the indicated JVM. This 1778// buffer may be kept in synchronization via shared memory 1779// or some other mechanism that keeps the buffer updated. 1780// 1781// If the JVM chooses not to support the attachability feature, 1782// this method should throw an UnsupportedOperation exception. 1783// 1784// This implementation utilizes named shared memory to map 1785// the indicated process's PerfData memory region into this JVMs 1786// address space. 1787// 1788void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, 1789 char** addrp, size_t* sizep, TRAPS) { 1790 1791 if (vmid == 0 || vmid == os::current_process_id()) { 1792 *addrp = start(); 1793 *sizep = capacity(); 1794 return; 1795 } 1796 1797 open_file_mapping(user, vmid, mode, addrp, sizep, CHECK); 1798} 1799 1800// detach from the PerfData memory region of another JVM 1801// 1802// This method detaches the PerfData memory region of another 1803// JVM, specified as an <address, size> tuple of a buffer 1804// in this process's address space. This method may perform 1805// arbitrary actions to accomplish the detachment. The memory 1806// region specified by <address, size> will be inaccessible after 1807// a call to this method. 1808// 1809// If the JVM chooses not to support the attachability feature, 1810// this method should throw an UnsupportedOperation exception. 1811// 1812// This implementation utilizes named shared memory to detach 1813// the indicated process's PerfData memory region from this 1814// process's address space. 1815// 1816void PerfMemory::detach(char* addr, size_t bytes, TRAPS) { 1817 1818 assert(addr != 0, "address sanity check"); 1819 assert(bytes > 0, "capacity sanity check"); 1820 1821 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) { 1822 // prevent accidental detachment of this process's PerfMemory region 1823 return; 1824 } 1825 1826 remove_file_mapping(addr); 1827} 1828 1829char* PerfMemory::backing_store_filename() { 1830 return sharedmem_fileName; 1831} 1832