Mercurial > hg > graal-compiler
comparison src/os/windows/vm/perfMemory_windows.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
parents | |
children | 98cb887364d3 |
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1 /* | |
2 * Copyright 2001-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_perfMemory_windows.cpp.incl" | |
27 | |
28 #include <windows.h> | |
29 #include <sys/types.h> | |
30 #include <sys/stat.h> | |
31 #include <errno.h> | |
32 #include <lmcons.h> | |
33 | |
34 typedef BOOL (WINAPI *SetSecurityDescriptorControlFnPtr)( | |
35 IN PSECURITY_DESCRIPTOR pSecurityDescriptor, | |
36 IN SECURITY_DESCRIPTOR_CONTROL ControlBitsOfInterest, | |
37 IN SECURITY_DESCRIPTOR_CONTROL ControlBitsToSet); | |
38 | |
39 // Standard Memory Implementation Details | |
40 | |
41 // create the PerfData memory region in standard memory. | |
42 // | |
43 static char* create_standard_memory(size_t size) { | |
44 | |
45 // allocate an aligned chuck of memory | |
46 char* mapAddress = os::reserve_memory(size); | |
47 | |
48 if (mapAddress == NULL) { | |
49 return NULL; | |
50 } | |
51 | |
52 // commit memory | |
53 if (!os::commit_memory(mapAddress, size)) { | |
54 if (PrintMiscellaneous && Verbose) { | |
55 warning("Could not commit PerfData memory\n"); | |
56 } | |
57 os::release_memory(mapAddress, size); | |
58 return NULL; | |
59 } | |
60 | |
61 return mapAddress; | |
62 } | |
63 | |
64 // delete the PerfData memory region | |
65 // | |
66 static void delete_standard_memory(char* addr, size_t size) { | |
67 | |
68 // there are no persistent external resources to cleanup for standard | |
69 // memory. since DestroyJavaVM does not support unloading of the JVM, | |
70 // cleanup of the memory resource is not performed. The memory will be | |
71 // reclaimed by the OS upon termination of the process. | |
72 // | |
73 return; | |
74 | |
75 } | |
76 | |
77 // save the specified memory region to the given file | |
78 // | |
79 static void save_memory_to_file(char* addr, size_t size) { | |
80 | |
81 const char* destfile = PerfMemory::get_perfdata_file_path(); | |
82 assert(destfile[0] != '\0', "invalid Perfdata file path"); | |
83 | |
84 int fd = ::_open(destfile, _O_BINARY|_O_CREAT|_O_WRONLY|_O_TRUNC, | |
85 _S_IREAD|_S_IWRITE); | |
86 | |
87 if (fd == OS_ERR) { | |
88 if (PrintMiscellaneous && Verbose) { | |
89 warning("Could not create Perfdata save file: %s: %s\n", | |
90 destfile, strerror(errno)); | |
91 } | |
92 } else { | |
93 for (size_t remaining = size; remaining > 0;) { | |
94 | |
95 int nbytes = ::_write(fd, addr, (unsigned int)remaining); | |
96 if (nbytes == OS_ERR) { | |
97 if (PrintMiscellaneous && Verbose) { | |
98 warning("Could not write Perfdata save file: %s: %s\n", | |
99 destfile, strerror(errno)); | |
100 } | |
101 break; | |
102 } | |
103 | |
104 remaining -= (size_t)nbytes; | |
105 addr += nbytes; | |
106 } | |
107 | |
108 int result = ::_close(fd); | |
109 if (PrintMiscellaneous && Verbose) { | |
110 if (result == OS_ERR) { | |
111 warning("Could not close %s: %s\n", destfile, strerror(errno)); | |
112 } | |
113 } | |
114 } | |
115 | |
116 FREE_C_HEAP_ARRAY(char, destfile); | |
117 } | |
118 | |
119 // Shared Memory Implementation Details | |
120 | |
121 // Note: the win32 shared memory implementation uses two objects to represent | |
122 // the shared memory: a windows kernel based file mapping object and a backing | |
123 // store file. On windows, the name space for shared memory is a kernel | |
124 // based name space that is disjoint from other win32 name spaces. Since Java | |
125 // is unaware of this name space, a parallel file system based name space is | |
126 // maintained, which provides a common file system based shared memory name | |
127 // space across the supported platforms and one that Java apps can deal with | |
128 // through simple file apis. | |
129 // | |
130 // For performance and resource cleanup reasons, it is recommended that the | |
131 // user specific directory and the backing store file be stored in either a | |
132 // RAM based file system or a local disk based file system. Network based | |
133 // file systems are not recommended for performance reasons. In addition, | |
134 // use of SMB network based file systems may result in unsuccesful cleanup | |
135 // of the disk based resource on exit of the VM. The Windows TMP and TEMP | |
136 // environement variables, as used by the GetTempPath() Win32 API (see | |
137 // os::get_temp_directory() in os_win32.cpp), control the location of the | |
138 // user specific directory and the shared memory backing store file. | |
139 | |
140 static HANDLE sharedmem_fileMapHandle = NULL; | |
141 static HANDLE sharedmem_fileHandle = INVALID_HANDLE_VALUE; | |
142 static char* sharedmem_fileName = NULL; | |
143 | |
144 // return the user specific temporary directory name. | |
145 // | |
146 // the caller is expected to free the allocated memory. | |
147 // | |
148 static char* get_user_tmp_dir(const char* user) { | |
149 | |
150 const char* tmpdir = os::get_temp_directory(); | |
151 const char* perfdir = PERFDATA_NAME; | |
152 size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 2; | |
153 char* dirname = NEW_C_HEAP_ARRAY(char, nbytes); | |
154 | |
155 // construct the path name to user specific tmp directory | |
156 _snprintf(dirname, nbytes, "%s%s_%s", tmpdir, perfdir, user); | |
157 | |
158 return dirname; | |
159 } | |
160 | |
161 // convert the given file name into a process id. if the file | |
162 // does not meet the file naming constraints, return 0. | |
163 // | |
164 static int filename_to_pid(const char* filename) { | |
165 | |
166 // a filename that doesn't begin with a digit is not a | |
167 // candidate for conversion. | |
168 // | |
169 if (!isdigit(*filename)) { | |
170 return 0; | |
171 } | |
172 | |
173 // check if file name can be converted to an integer without | |
174 // any leftover characters. | |
175 // | |
176 char* remainder = NULL; | |
177 errno = 0; | |
178 int pid = (int)strtol(filename, &remainder, 10); | |
179 | |
180 if (errno != 0) { | |
181 return 0; | |
182 } | |
183 | |
184 // check for left over characters. If any, then the filename is | |
185 // not a candidate for conversion. | |
186 // | |
187 if (remainder != NULL && *remainder != '\0') { | |
188 return 0; | |
189 } | |
190 | |
191 // successful conversion, return the pid | |
192 return pid; | |
193 } | |
194 | |
195 // check if the given path is considered a secure directory for | |
196 // the backing store files. Returns true if the directory exists | |
197 // and is considered a secure location. Returns false if the path | |
198 // is a symbolic link or if an error occured. | |
199 // | |
200 static bool is_directory_secure(const char* path) { | |
201 | |
202 DWORD fa; | |
203 | |
204 fa = GetFileAttributes(path); | |
205 if (fa == 0xFFFFFFFF) { | |
206 DWORD lasterror = GetLastError(); | |
207 if (lasterror == ERROR_FILE_NOT_FOUND) { | |
208 return false; | |
209 } | |
210 else { | |
211 // unexpected error, declare the path insecure | |
212 if (PrintMiscellaneous && Verbose) { | |
213 warning("could not get attributes for file %s: ", | |
214 " lasterror = %d\n", path, lasterror); | |
215 } | |
216 return false; | |
217 } | |
218 } | |
219 | |
220 if (fa & FILE_ATTRIBUTE_REPARSE_POINT) { | |
221 // we don't accept any redirection for the user specific directory | |
222 // so declare the path insecure. This may be too conservative, | |
223 // as some types of reparse points might be acceptable, but it | |
224 // is probably more secure to avoid these conditions. | |
225 // | |
226 if (PrintMiscellaneous && Verbose) { | |
227 warning("%s is a reparse point\n", path); | |
228 } | |
229 return false; | |
230 } | |
231 | |
232 if (fa & FILE_ATTRIBUTE_DIRECTORY) { | |
233 // this is the expected case. Since windows supports symbolic | |
234 // links to directories only, not to files, there is no need | |
235 // to check for open write permissions on the directory. If the | |
236 // directory has open write permissions, any files deposited that | |
237 // are not expected will be removed by the cleanup code. | |
238 // | |
239 return true; | |
240 } | |
241 else { | |
242 // this is either a regular file or some other type of file, | |
243 // any of which are unexpected and therefore insecure. | |
244 // | |
245 if (PrintMiscellaneous && Verbose) { | |
246 warning("%s is not a directory, file attributes = " | |
247 INTPTR_FORMAT "\n", path, fa); | |
248 } | |
249 return false; | |
250 } | |
251 } | |
252 | |
253 // return the user name for the owner of this process | |
254 // | |
255 // the caller is expected to free the allocated memory. | |
256 // | |
257 static char* get_user_name() { | |
258 | |
259 /* get the user name. This code is adapted from code found in | |
260 * the jdk in src/windows/native/java/lang/java_props_md.c | |
261 * java_props_md.c 1.29 02/02/06. According to the original | |
262 * source, the call to GetUserName is avoided because of a resulting | |
263 * increase in footprint of 100K. | |
264 */ | |
265 char* user = getenv("USERNAME"); | |
266 char buf[UNLEN+1]; | |
267 DWORD buflen = sizeof(buf); | |
268 if (user == NULL || strlen(user) == 0) { | |
269 if (GetUserName(buf, &buflen)) { | |
270 user = buf; | |
271 } | |
272 else { | |
273 return NULL; | |
274 } | |
275 } | |
276 | |
277 char* user_name = NEW_C_HEAP_ARRAY(char, strlen(user)+1); | |
278 strcpy(user_name, user); | |
279 | |
280 return user_name; | |
281 } | |
282 | |
283 // return the name of the user that owns the process identified by vmid. | |
284 // | |
285 // This method uses a slow directory search algorithm to find the backing | |
286 // store file for the specified vmid and returns the user name, as determined | |
287 // by the user name suffix of the hsperfdata_<username> directory name. | |
288 // | |
289 // the caller is expected to free the allocated memory. | |
290 // | |
291 static char* get_user_name_slow(int vmid) { | |
292 | |
293 // directory search | |
294 char* oldest_user = NULL; | |
295 time_t oldest_ctime = 0; | |
296 | |
297 const char* tmpdirname = os::get_temp_directory(); | |
298 | |
299 DIR* tmpdirp = os::opendir(tmpdirname); | |
300 | |
301 if (tmpdirp == NULL) { | |
302 return NULL; | |
303 } | |
304 | |
305 // for each entry in the directory that matches the pattern hsperfdata_*, | |
306 // open the directory and check if the file for the given vmid exists. | |
307 // The file with the expected name and the latest creation date is used | |
308 // to determine the user name for the process id. | |
309 // | |
310 struct dirent* dentry; | |
311 char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname)); | |
312 errno = 0; | |
313 while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) { | |
314 | |
315 // check if the directory entry is a hsperfdata file | |
316 if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) { | |
317 continue; | |
318 } | |
319 | |
320 char* usrdir_name = NEW_C_HEAP_ARRAY(char, | |
321 strlen(tmpdirname) + strlen(dentry->d_name) + 1); | |
322 strcpy(usrdir_name, tmpdirname); | |
323 strcat(usrdir_name, dentry->d_name); | |
324 | |
325 DIR* subdirp = os::opendir(usrdir_name); | |
326 | |
327 if (subdirp == NULL) { | |
328 FREE_C_HEAP_ARRAY(char, usrdir_name); | |
329 continue; | |
330 } | |
331 | |
332 // Since we don't create the backing store files in directories | |
333 // pointed to by symbolic links, we also don't follow them when | |
334 // looking for the files. We check for a symbolic link after the | |
335 // call to opendir in order to eliminate a small window where the | |
336 // symlink can be exploited. | |
337 // | |
338 if (!is_directory_secure(usrdir_name)) { | |
339 FREE_C_HEAP_ARRAY(char, usrdir_name); | |
340 os::closedir(subdirp); | |
341 continue; | |
342 } | |
343 | |
344 struct dirent* udentry; | |
345 char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name)); | |
346 errno = 0; | |
347 while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) { | |
348 | |
349 if (filename_to_pid(udentry->d_name) == vmid) { | |
350 struct stat statbuf; | |
351 | |
352 char* filename = NEW_C_HEAP_ARRAY(char, | |
353 strlen(usrdir_name) + strlen(udentry->d_name) + 2); | |
354 | |
355 strcpy(filename, usrdir_name); | |
356 strcat(filename, "\\"); | |
357 strcat(filename, udentry->d_name); | |
358 | |
359 if (::stat(filename, &statbuf) == OS_ERR) { | |
360 FREE_C_HEAP_ARRAY(char, filename); | |
361 continue; | |
362 } | |
363 | |
364 // skip over files that are not regular files. | |
365 if ((statbuf.st_mode & S_IFMT) != S_IFREG) { | |
366 FREE_C_HEAP_ARRAY(char, filename); | |
367 continue; | |
368 } | |
369 | |
370 // compare and save filename with latest creation time | |
371 if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) { | |
372 | |
373 if (statbuf.st_ctime > oldest_ctime) { | |
374 char* user = strchr(dentry->d_name, '_') + 1; | |
375 | |
376 if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user); | |
377 oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1); | |
378 | |
379 strcpy(oldest_user, user); | |
380 oldest_ctime = statbuf.st_ctime; | |
381 } | |
382 } | |
383 | |
384 FREE_C_HEAP_ARRAY(char, filename); | |
385 } | |
386 } | |
387 os::closedir(subdirp); | |
388 FREE_C_HEAP_ARRAY(char, udbuf); | |
389 FREE_C_HEAP_ARRAY(char, usrdir_name); | |
390 } | |
391 os::closedir(tmpdirp); | |
392 FREE_C_HEAP_ARRAY(char, tdbuf); | |
393 | |
394 return(oldest_user); | |
395 } | |
396 | |
397 // return the name of the user that owns the process identified by vmid. | |
398 // | |
399 // note: this method should only be used via the Perf native methods. | |
400 // There are various costs to this method and limiting its use to the | |
401 // Perf native methods limits the impact to monitoring applications only. | |
402 // | |
403 static char* get_user_name(int vmid) { | |
404 | |
405 // A fast implementation is not provided at this time. It's possible | |
406 // to provide a fast process id to user name mapping function using | |
407 // the win32 apis, but the default ACL for the process object only | |
408 // allows processes with the same owner SID to acquire the process | |
409 // handle (via OpenProcess(PROCESS_QUERY_INFORMATION)). It's possible | |
410 // to have the JVM change the ACL for the process object to allow arbitrary | |
411 // users to access the process handle and the process security token. | |
412 // The security ramifications need to be studied before providing this | |
413 // mechanism. | |
414 // | |
415 return get_user_name_slow(vmid); | |
416 } | |
417 | |
418 // return the name of the shared memory file mapping object for the | |
419 // named shared memory region for the given user name and vmid. | |
420 // | |
421 // The file mapping object's name is not the file name. It is a name | |
422 // in a separate name space. | |
423 // | |
424 // the caller is expected to free the allocated memory. | |
425 // | |
426 static char *get_sharedmem_objectname(const char* user, int vmid) { | |
427 | |
428 // construct file mapping object's name, add 3 for two '_' and a | |
429 // null terminator. | |
430 int nbytes = (int)strlen(PERFDATA_NAME) + (int)strlen(user) + 3; | |
431 | |
432 // the id is converted to an unsigned value here because win32 allows | |
433 // negative process ids. However, OpenFileMapping API complains | |
434 // about a name containing a '-' characters. | |
435 // | |
436 nbytes += UINT_CHARS; | |
437 char* name = NEW_C_HEAP_ARRAY(char, nbytes); | |
438 _snprintf(name, nbytes, "%s_%s_%u", PERFDATA_NAME, user, vmid); | |
439 | |
440 return name; | |
441 } | |
442 | |
443 // return the file name of the backing store file for the named | |
444 // shared memory region for the given user name and vmid. | |
445 // | |
446 // the caller is expected to free the allocated memory. | |
447 // | |
448 static char* get_sharedmem_filename(const char* dirname, int vmid) { | |
449 | |
450 // add 2 for the file separator and a null terminator. | |
451 size_t nbytes = strlen(dirname) + UINT_CHARS + 2; | |
452 | |
453 char* name = NEW_C_HEAP_ARRAY(char, nbytes); | |
454 _snprintf(name, nbytes, "%s\\%d", dirname, vmid); | |
455 | |
456 return name; | |
457 } | |
458 | |
459 // remove file | |
460 // | |
461 // this method removes the file with the given file name. | |
462 // | |
463 // Note: if the indicated file is on an SMB network file system, this | |
464 // method may be unsuccessful in removing the file. | |
465 // | |
466 static void remove_file(const char* dirname, const char* filename) { | |
467 | |
468 size_t nbytes = strlen(dirname) + strlen(filename) + 2; | |
469 char* path = NEW_C_HEAP_ARRAY(char, nbytes); | |
470 | |
471 strcpy(path, dirname); | |
472 strcat(path, "\\"); | |
473 strcat(path, filename); | |
474 | |
475 if (::unlink(path) == OS_ERR) { | |
476 if (PrintMiscellaneous && Verbose) { | |
477 if (errno != ENOENT) { | |
478 warning("Could not unlink shared memory backing" | |
479 " store file %s : %s\n", path, strerror(errno)); | |
480 } | |
481 } | |
482 } | |
483 | |
484 FREE_C_HEAP_ARRAY(char, path); | |
485 } | |
486 | |
487 // returns true if the process represented by pid is alive, otherwise | |
488 // returns false. the validity of the result is only accurate if the | |
489 // target process is owned by the same principal that owns this process. | |
490 // this method should not be used if to test the status of an otherwise | |
491 // arbitrary process unless it is know that this process has the appropriate | |
492 // privileges to guarantee a result valid. | |
493 // | |
494 static bool is_alive(int pid) { | |
495 | |
496 HANDLE ph = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid); | |
497 if (ph == NULL) { | |
498 // the process does not exist. | |
499 if (PrintMiscellaneous && Verbose) { | |
500 DWORD lastError = GetLastError(); | |
501 if (lastError != ERROR_INVALID_PARAMETER) { | |
502 warning("OpenProcess failed: %d\n", GetLastError()); | |
503 } | |
504 } | |
505 return false; | |
506 } | |
507 | |
508 DWORD exit_status; | |
509 if (!GetExitCodeProcess(ph, &exit_status)) { | |
510 if (PrintMiscellaneous && Verbose) { | |
511 warning("GetExitCodeProcess failed: %d\n", GetLastError()); | |
512 } | |
513 CloseHandle(ph); | |
514 return false; | |
515 } | |
516 | |
517 CloseHandle(ph); | |
518 return (exit_status == STILL_ACTIVE) ? true : false; | |
519 } | |
520 | |
521 // check if the file system is considered secure for the backing store files | |
522 // | |
523 static bool is_filesystem_secure(const char* path) { | |
524 | |
525 char root_path[MAX_PATH]; | |
526 char fs_type[MAX_PATH]; | |
527 | |
528 if (PerfBypassFileSystemCheck) { | |
529 if (PrintMiscellaneous && Verbose) { | |
530 warning("bypassing file system criteria checks for %s\n", path); | |
531 } | |
532 return true; | |
533 } | |
534 | |
535 char* first_colon = strchr((char *)path, ':'); | |
536 if (first_colon == NULL) { | |
537 if (PrintMiscellaneous && Verbose) { | |
538 warning("expected device specifier in path: %s\n", path); | |
539 } | |
540 return false; | |
541 } | |
542 | |
543 size_t len = (size_t)(first_colon - path); | |
544 assert(len + 2 <= MAX_PATH, "unexpected device specifier length"); | |
545 strncpy(root_path, path, len + 1); | |
546 root_path[len + 1] = '\\'; | |
547 root_path[len + 2] = '\0'; | |
548 | |
549 // check that we have something like "C:\" or "AA:\" | |
550 assert(strlen(root_path) >= 3, "device specifier too short"); | |
551 assert(strchr(root_path, ':') != NULL, "bad device specifier format"); | |
552 assert(strchr(root_path, '\\') != NULL, "bad device specifier format"); | |
553 | |
554 DWORD maxpath; | |
555 DWORD flags; | |
556 | |
557 if (!GetVolumeInformation(root_path, NULL, 0, NULL, &maxpath, | |
558 &flags, fs_type, MAX_PATH)) { | |
559 // we can't get information about the volume, so assume unsafe. | |
560 if (PrintMiscellaneous && Verbose) { | |
561 warning("could not get device information for %s: " | |
562 " path = %s: lasterror = %d\n", | |
563 root_path, path, GetLastError()); | |
564 } | |
565 return false; | |
566 } | |
567 | |
568 if ((flags & FS_PERSISTENT_ACLS) == 0) { | |
569 // file system doesn't support ACLs, declare file system unsafe | |
570 if (PrintMiscellaneous && Verbose) { | |
571 warning("file system type %s on device %s does not support" | |
572 " ACLs\n", fs_type, root_path); | |
573 } | |
574 return false; | |
575 } | |
576 | |
577 if ((flags & FS_VOL_IS_COMPRESSED) != 0) { | |
578 // file system is compressed, declare file system unsafe | |
579 if (PrintMiscellaneous && Verbose) { | |
580 warning("file system type %s on device %s is compressed\n", | |
581 fs_type, root_path); | |
582 } | |
583 return false; | |
584 } | |
585 | |
586 return true; | |
587 } | |
588 | |
589 // cleanup stale shared memory resources | |
590 // | |
591 // This method attempts to remove all stale shared memory files in | |
592 // the named user temporary directory. It scans the named directory | |
593 // for files matching the pattern ^$[0-9]*$. For each file found, the | |
594 // process id is extracted from the file name and a test is run to | |
595 // determine if the process is alive. If the process is not alive, | |
596 // any stale file resources are removed. | |
597 // | |
598 static void cleanup_sharedmem_resources(const char* dirname) { | |
599 | |
600 // open the user temp directory | |
601 DIR* dirp = os::opendir(dirname); | |
602 | |
603 if (dirp == NULL) { | |
604 // directory doesn't exist, so there is nothing to cleanup | |
605 return; | |
606 } | |
607 | |
608 if (!is_directory_secure(dirname)) { | |
609 // the directory is not secure, don't attempt any cleanup | |
610 return; | |
611 } | |
612 | |
613 // for each entry in the directory that matches the expected file | |
614 // name pattern, determine if the file resources are stale and if | |
615 // so, remove the file resources. Note, instrumented HotSpot processes | |
616 // for this user may start and/or terminate during this search and | |
617 // remove or create new files in this directory. The behavior of this | |
618 // loop under these conditions is dependent upon the implementation of | |
619 // opendir/readdir. | |
620 // | |
621 struct dirent* entry; | |
622 char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname)); | |
623 errno = 0; | |
624 while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) { | |
625 | |
626 int pid = filename_to_pid(entry->d_name); | |
627 | |
628 if (pid == 0) { | |
629 | |
630 if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) { | |
631 | |
632 // attempt to remove all unexpected files, except "." and ".." | |
633 remove_file(dirname, entry->d_name); | |
634 } | |
635 | |
636 errno = 0; | |
637 continue; | |
638 } | |
639 | |
640 // we now have a file name that converts to a valid integer | |
641 // that could represent a process id . if this process id | |
642 // matches the current process id or the process is not running, | |
643 // then remove the stale file resources. | |
644 // | |
645 // process liveness is detected by checking the exit status | |
646 // of the process. if the process id is valid and the exit status | |
647 // indicates that it is still running, the file file resources | |
648 // are not removed. If the process id is invalid, or if we don't | |
649 // have permissions to check the process status, or if the process | |
650 // id is valid and the process has terminated, the the file resources | |
651 // are assumed to be stale and are removed. | |
652 // | |
653 if (pid == os::current_process_id() || !is_alive(pid)) { | |
654 | |
655 // we can only remove the file resources. Any mapped views | |
656 // of the file can only be unmapped by the processes that | |
657 // opened those views and the file mapping object will not | |
658 // get removed until all views are unmapped. | |
659 // | |
660 remove_file(dirname, entry->d_name); | |
661 } | |
662 errno = 0; | |
663 } | |
664 os::closedir(dirp); | |
665 FREE_C_HEAP_ARRAY(char, dbuf); | |
666 } | |
667 | |
668 // create a file mapping object with the requested name, and size | |
669 // from the file represented by the given Handle object | |
670 // | |
671 static HANDLE create_file_mapping(const char* name, HANDLE fh, LPSECURITY_ATTRIBUTES fsa, size_t size) { | |
672 | |
673 DWORD lowSize = (DWORD)size; | |
674 DWORD highSize = 0; | |
675 HANDLE fmh = NULL; | |
676 | |
677 // Create a file mapping object with the given name. This function | |
678 // will grow the file to the specified size. | |
679 // | |
680 fmh = CreateFileMapping( | |
681 fh, /* HANDLE file handle for backing store */ | |
682 fsa, /* LPSECURITY_ATTRIBUTES Not inheritable */ | |
683 PAGE_READWRITE, /* DWORD protections */ | |
684 highSize, /* DWORD High word of max size */ | |
685 lowSize, /* DWORD Low word of max size */ | |
686 name); /* LPCTSTR name for object */ | |
687 | |
688 if (fmh == NULL) { | |
689 if (PrintMiscellaneous && Verbose) { | |
690 warning("CreateFileMapping failed, lasterror = %d\n", GetLastError()); | |
691 } | |
692 return NULL; | |
693 } | |
694 | |
695 if (GetLastError() == ERROR_ALREADY_EXISTS) { | |
696 | |
697 // a stale file mapping object was encountered. This object may be | |
698 // owned by this or some other user and cannot be removed until | |
699 // the other processes either exit or close their mapping objects | |
700 // and/or mapped views of this mapping object. | |
701 // | |
702 if (PrintMiscellaneous && Verbose) { | |
703 warning("file mapping already exists, lasterror = %d\n", GetLastError()); | |
704 } | |
705 | |
706 CloseHandle(fmh); | |
707 return NULL; | |
708 } | |
709 | |
710 return fmh; | |
711 } | |
712 | |
713 | |
714 // method to free the given security descriptor and the contained | |
715 // access control list. | |
716 // | |
717 static void free_security_desc(PSECURITY_DESCRIPTOR pSD) { | |
718 | |
719 BOOL success, exists, isdefault; | |
720 PACL pACL; | |
721 | |
722 if (pSD != NULL) { | |
723 | |
724 // get the access control list from the security descriptor | |
725 success = GetSecurityDescriptorDacl(pSD, &exists, &pACL, &isdefault); | |
726 | |
727 // if an ACL existed and it was not a default acl, then it must | |
728 // be an ACL we enlisted. free the resources. | |
729 // | |
730 if (success && exists && pACL != NULL && !isdefault) { | |
731 FREE_C_HEAP_ARRAY(char, pACL); | |
732 } | |
733 | |
734 // free the security descriptor | |
735 FREE_C_HEAP_ARRAY(char, pSD); | |
736 } | |
737 } | |
738 | |
739 // method to free up a security attributes structure and any | |
740 // contained security descriptors and ACL | |
741 // | |
742 static void free_security_attr(LPSECURITY_ATTRIBUTES lpSA) { | |
743 | |
744 if (lpSA != NULL) { | |
745 // free the contained security descriptor and the ACL | |
746 free_security_desc(lpSA->lpSecurityDescriptor); | |
747 lpSA->lpSecurityDescriptor = NULL; | |
748 | |
749 // free the security attributes structure | |
750 FREE_C_HEAP_ARRAY(char, lpSA); | |
751 } | |
752 } | |
753 | |
754 // get the user SID for the process indicated by the process handle | |
755 // | |
756 static PSID get_user_sid(HANDLE hProcess) { | |
757 | |
758 HANDLE hAccessToken; | |
759 PTOKEN_USER token_buf = NULL; | |
760 DWORD rsize = 0; | |
761 | |
762 if (hProcess == NULL) { | |
763 return NULL; | |
764 } | |
765 | |
766 // get the process token | |
767 if (!OpenProcessToken(hProcess, TOKEN_READ, &hAccessToken)) { | |
768 if (PrintMiscellaneous && Verbose) { | |
769 warning("OpenProcessToken failure: lasterror = %d \n", GetLastError()); | |
770 } | |
771 return NULL; | |
772 } | |
773 | |
774 // determine the size of the token structured needed to retrieve | |
775 // the user token information from the access token. | |
776 // | |
777 if (!GetTokenInformation(hAccessToken, TokenUser, NULL, rsize, &rsize)) { | |
778 DWORD lasterror = GetLastError(); | |
779 if (lasterror != ERROR_INSUFFICIENT_BUFFER) { | |
780 if (PrintMiscellaneous && Verbose) { | |
781 warning("GetTokenInformation failure: lasterror = %d," | |
782 " rsize = %d\n", lasterror, rsize); | |
783 } | |
784 CloseHandle(hAccessToken); | |
785 return NULL; | |
786 } | |
787 } | |
788 | |
789 token_buf = (PTOKEN_USER) NEW_C_HEAP_ARRAY(char, rsize); | |
790 | |
791 // get the user token information | |
792 if (!GetTokenInformation(hAccessToken, TokenUser, token_buf, rsize, &rsize)) { | |
793 if (PrintMiscellaneous && Verbose) { | |
794 warning("GetTokenInformation failure: lasterror = %d," | |
795 " rsize = %d\n", GetLastError(), rsize); | |
796 } | |
797 FREE_C_HEAP_ARRAY(char, token_buf); | |
798 CloseHandle(hAccessToken); | |
799 return NULL; | |
800 } | |
801 | |
802 DWORD nbytes = GetLengthSid(token_buf->User.Sid); | |
803 PSID pSID = NEW_C_HEAP_ARRAY(char, nbytes); | |
804 | |
805 if (!CopySid(nbytes, pSID, token_buf->User.Sid)) { | |
806 if (PrintMiscellaneous && Verbose) { | |
807 warning("GetTokenInformation failure: lasterror = %d," | |
808 " rsize = %d\n", GetLastError(), rsize); | |
809 } | |
810 FREE_C_HEAP_ARRAY(char, token_buf); | |
811 FREE_C_HEAP_ARRAY(char, pSID); | |
812 CloseHandle(hAccessToken); | |
813 return NULL; | |
814 } | |
815 | |
816 // close the access token. | |
817 CloseHandle(hAccessToken); | |
818 FREE_C_HEAP_ARRAY(char, token_buf); | |
819 | |
820 return pSID; | |
821 } | |
822 | |
823 // structure used to consolidate access control entry information | |
824 // | |
825 typedef struct ace_data { | |
826 PSID pSid; // SID of the ACE | |
827 DWORD mask; // mask for the ACE | |
828 } ace_data_t; | |
829 | |
830 | |
831 // method to add an allow access control entry with the access rights | |
832 // indicated in mask for the principal indicated in SID to the given | |
833 // security descriptor. Much of the DACL handling was adapted from | |
834 // the example provided here: | |
835 // http://support.microsoft.com/kb/102102/EN-US/ | |
836 // | |
837 | |
838 static bool add_allow_aces(PSECURITY_DESCRIPTOR pSD, | |
839 ace_data_t aces[], int ace_count) { | |
840 PACL newACL = NULL; | |
841 PACL oldACL = NULL; | |
842 | |
843 if (pSD == NULL) { | |
844 return false; | |
845 } | |
846 | |
847 BOOL exists, isdefault; | |
848 | |
849 // retrieve any existing access control list. | |
850 if (!GetSecurityDescriptorDacl(pSD, &exists, &oldACL, &isdefault)) { | |
851 if (PrintMiscellaneous && Verbose) { | |
852 warning("GetSecurityDescriptor failure: lasterror = %d \n", | |
853 GetLastError()); | |
854 } | |
855 return false; | |
856 } | |
857 | |
858 // get the size of the DACL | |
859 ACL_SIZE_INFORMATION aclinfo; | |
860 | |
861 // GetSecurityDescriptorDacl may return true value for exists (lpbDaclPresent) | |
862 // while oldACL is NULL for some case. | |
863 if (oldACL == NULL) { | |
864 exists = FALSE; | |
865 } | |
866 | |
867 if (exists) { | |
868 if (!GetAclInformation(oldACL, &aclinfo, | |
869 sizeof(ACL_SIZE_INFORMATION), | |
870 AclSizeInformation)) { | |
871 if (PrintMiscellaneous && Verbose) { | |
872 warning("GetAclInformation failure: lasterror = %d \n", GetLastError()); | |
873 return false; | |
874 } | |
875 } | |
876 } else { | |
877 aclinfo.AceCount = 0; // assume NULL DACL | |
878 aclinfo.AclBytesFree = 0; | |
879 aclinfo.AclBytesInUse = sizeof(ACL); | |
880 } | |
881 | |
882 // compute the size needed for the new ACL | |
883 // initial size of ACL is sum of the following: | |
884 // * size of ACL structure. | |
885 // * size of each ACE structure that ACL is to contain minus the sid | |
886 // sidStart member (DWORD) of the ACE. | |
887 // * length of the SID that each ACE is to contain. | |
888 DWORD newACLsize = aclinfo.AclBytesInUse + | |
889 (sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD)) * ace_count; | |
890 for (int i = 0; i < ace_count; i++) { | |
891 newACLsize += GetLengthSid(aces[i].pSid); | |
892 } | |
893 | |
894 // create the new ACL | |
895 newACL = (PACL) NEW_C_HEAP_ARRAY(char, newACLsize); | |
896 | |
897 if (!InitializeAcl(newACL, newACLsize, ACL_REVISION)) { | |
898 if (PrintMiscellaneous && Verbose) { | |
899 warning("InitializeAcl failure: lasterror = %d \n", GetLastError()); | |
900 } | |
901 FREE_C_HEAP_ARRAY(char, newACL); | |
902 return false; | |
903 } | |
904 | |
905 unsigned int ace_index = 0; | |
906 // copy any existing ACEs from the old ACL (if any) to the new ACL. | |
907 if (aclinfo.AceCount != 0) { | |
908 while (ace_index < aclinfo.AceCount) { | |
909 LPVOID ace; | |
910 if (!GetAce(oldACL, ace_index, &ace)) { | |
911 if (PrintMiscellaneous && Verbose) { | |
912 warning("InitializeAcl failure: lasterror = %d \n", GetLastError()); | |
913 } | |
914 FREE_C_HEAP_ARRAY(char, newACL); | |
915 return false; | |
916 } | |
917 if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceFlags && INHERITED_ACE) { | |
918 // this is an inherited, allowed ACE; break from loop so we can | |
919 // add the new access allowed, non-inherited ACE in the correct | |
920 // position, immediately following all non-inherited ACEs. | |
921 break; | |
922 } | |
923 | |
924 // determine if the SID of this ACE matches any of the SIDs | |
925 // for which we plan to set ACEs. | |
926 int matches = 0; | |
927 for (int i = 0; i < ace_count; i++) { | |
928 if (EqualSid(aces[i].pSid, &(((ACCESS_ALLOWED_ACE *)ace)->SidStart))) { | |
929 matches++; | |
930 break; | |
931 } | |
932 } | |
933 | |
934 // if there are no SID matches, then add this existing ACE to the new ACL | |
935 if (matches == 0) { | |
936 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace, | |
937 ((PACE_HEADER)ace)->AceSize)) { | |
938 if (PrintMiscellaneous && Verbose) { | |
939 warning("AddAce failure: lasterror = %d \n", GetLastError()); | |
940 } | |
941 FREE_C_HEAP_ARRAY(char, newACL); | |
942 return false; | |
943 } | |
944 } | |
945 ace_index++; | |
946 } | |
947 } | |
948 | |
949 // add the passed-in access control entries to the new ACL | |
950 for (int i = 0; i < ace_count; i++) { | |
951 if (!AddAccessAllowedAce(newACL, ACL_REVISION, | |
952 aces[i].mask, aces[i].pSid)) { | |
953 if (PrintMiscellaneous && Verbose) { | |
954 warning("AddAccessAllowedAce failure: lasterror = %d \n", | |
955 GetLastError()); | |
956 } | |
957 FREE_C_HEAP_ARRAY(char, newACL); | |
958 return false; | |
959 } | |
960 } | |
961 | |
962 // now copy the rest of the inherited ACEs from the old ACL | |
963 if (aclinfo.AceCount != 0) { | |
964 // picking up at ace_index, where we left off in the | |
965 // previous ace_index loop | |
966 while (ace_index < aclinfo.AceCount) { | |
967 LPVOID ace; | |
968 if (!GetAce(oldACL, ace_index, &ace)) { | |
969 if (PrintMiscellaneous && Verbose) { | |
970 warning("InitializeAcl failure: lasterror = %d \n", GetLastError()); | |
971 } | |
972 FREE_C_HEAP_ARRAY(char, newACL); | |
973 return false; | |
974 } | |
975 if (!AddAce(newACL, ACL_REVISION, MAXDWORD, ace, | |
976 ((PACE_HEADER)ace)->AceSize)) { | |
977 if (PrintMiscellaneous && Verbose) { | |
978 warning("AddAce failure: lasterror = %d \n", GetLastError()); | |
979 } | |
980 FREE_C_HEAP_ARRAY(char, newACL); | |
981 return false; | |
982 } | |
983 ace_index++; | |
984 } | |
985 } | |
986 | |
987 // add the new ACL to the security descriptor. | |
988 if (!SetSecurityDescriptorDacl(pSD, TRUE, newACL, FALSE)) { | |
989 if (PrintMiscellaneous && Verbose) { | |
990 warning("SetSecurityDescriptorDacl failure:" | |
991 " lasterror = %d \n", GetLastError()); | |
992 } | |
993 FREE_C_HEAP_ARRAY(char, newACL); | |
994 return false; | |
995 } | |
996 | |
997 // if running on windows 2000 or later, set the automatic inheritence | |
998 // control flags. | |
999 SetSecurityDescriptorControlFnPtr _SetSecurityDescriptorControl; | |
1000 _SetSecurityDescriptorControl = (SetSecurityDescriptorControlFnPtr) | |
1001 GetProcAddress(GetModuleHandle(TEXT("advapi32.dll")), | |
1002 "SetSecurityDescriptorControl"); | |
1003 | |
1004 if (_SetSecurityDescriptorControl != NULL) { | |
1005 // We do not want to further propogate inherited DACLs, so making them | |
1006 // protected prevents that. | |
1007 if (!_SetSecurityDescriptorControl(pSD, SE_DACL_PROTECTED, | |
1008 SE_DACL_PROTECTED)) { | |
1009 if (PrintMiscellaneous && Verbose) { | |
1010 warning("SetSecurityDescriptorControl failure:" | |
1011 " lasterror = %d \n", GetLastError()); | |
1012 } | |
1013 FREE_C_HEAP_ARRAY(char, newACL); | |
1014 return false; | |
1015 } | |
1016 } | |
1017 // Note, the security descriptor maintains a reference to the newACL, not | |
1018 // a copy of it. Therefore, the newACL is not freed here. It is freed when | |
1019 // the security descriptor containing its reference is freed. | |
1020 // | |
1021 return true; | |
1022 } | |
1023 | |
1024 // method to create a security attributes structure, which contains a | |
1025 // security descriptor and an access control list comprised of 0 or more | |
1026 // access control entries. The method take an array of ace_data structures | |
1027 // that indicate the ACE to be added to the security descriptor. | |
1028 // | |
1029 // the caller must free the resources associated with the security | |
1030 // attributes structure created by this method by calling the | |
1031 // free_security_attr() method. | |
1032 // | |
1033 static LPSECURITY_ATTRIBUTES make_security_attr(ace_data_t aces[], int count) { | |
1034 | |
1035 // allocate space for a security descriptor | |
1036 PSECURITY_DESCRIPTOR pSD = (PSECURITY_DESCRIPTOR) | |
1037 NEW_C_HEAP_ARRAY(char, SECURITY_DESCRIPTOR_MIN_LENGTH); | |
1038 | |
1039 // initialize the security descriptor | |
1040 if (!InitializeSecurityDescriptor(pSD, SECURITY_DESCRIPTOR_REVISION)) { | |
1041 if (PrintMiscellaneous && Verbose) { | |
1042 warning("InitializeSecurityDescriptor failure: " | |
1043 "lasterror = %d \n", GetLastError()); | |
1044 } | |
1045 free_security_desc(pSD); | |
1046 return NULL; | |
1047 } | |
1048 | |
1049 // add the access control entries | |
1050 if (!add_allow_aces(pSD, aces, count)) { | |
1051 free_security_desc(pSD); | |
1052 return NULL; | |
1053 } | |
1054 | |
1055 // allocate and initialize the security attributes structure and | |
1056 // return it to the caller. | |
1057 // | |
1058 LPSECURITY_ATTRIBUTES lpSA = (LPSECURITY_ATTRIBUTES) | |
1059 NEW_C_HEAP_ARRAY(char, sizeof(SECURITY_ATTRIBUTES)); | |
1060 lpSA->nLength = sizeof(SECURITY_ATTRIBUTES); | |
1061 lpSA->lpSecurityDescriptor = pSD; | |
1062 lpSA->bInheritHandle = FALSE; | |
1063 | |
1064 return(lpSA); | |
1065 } | |
1066 | |
1067 // method to create a security attributes structure with a restrictive | |
1068 // access control list that creates a set access rights for the user/owner | |
1069 // of the securable object and a separate set access rights for everyone else. | |
1070 // also provides for full access rights for the administrator group. | |
1071 // | |
1072 // the caller must free the resources associated with the security | |
1073 // attributes structure created by this method by calling the | |
1074 // free_security_attr() method. | |
1075 // | |
1076 | |
1077 static LPSECURITY_ATTRIBUTES make_user_everybody_admin_security_attr( | |
1078 DWORD umask, DWORD emask, DWORD amask) { | |
1079 | |
1080 ace_data_t aces[3]; | |
1081 | |
1082 // initialize the user ace data | |
1083 aces[0].pSid = get_user_sid(GetCurrentProcess()); | |
1084 aces[0].mask = umask; | |
1085 | |
1086 // get the well known SID for BUILTIN\Administrators | |
1087 PSID administratorsSid = NULL; | |
1088 SID_IDENTIFIER_AUTHORITY SIDAuthAdministrators = SECURITY_NT_AUTHORITY; | |
1089 | |
1090 if (!AllocateAndInitializeSid( &SIDAuthAdministrators, 2, | |
1091 SECURITY_BUILTIN_DOMAIN_RID, | |
1092 DOMAIN_ALIAS_RID_ADMINS, | |
1093 0, 0, 0, 0, 0, 0, &administratorsSid)) { | |
1094 | |
1095 if (PrintMiscellaneous && Verbose) { | |
1096 warning("AllocateAndInitializeSid failure: " | |
1097 "lasterror = %d \n", GetLastError()); | |
1098 } | |
1099 return NULL; | |
1100 } | |
1101 | |
1102 // initialize the ace data for administrator group | |
1103 aces[1].pSid = administratorsSid; | |
1104 aces[1].mask = amask; | |
1105 | |
1106 // get the well known SID for the universal Everybody | |
1107 PSID everybodySid = NULL; | |
1108 SID_IDENTIFIER_AUTHORITY SIDAuthEverybody = SECURITY_WORLD_SID_AUTHORITY; | |
1109 | |
1110 if (!AllocateAndInitializeSid( &SIDAuthEverybody, 1, SECURITY_WORLD_RID, | |
1111 0, 0, 0, 0, 0, 0, 0, &everybodySid)) { | |
1112 | |
1113 if (PrintMiscellaneous && Verbose) { | |
1114 warning("AllocateAndInitializeSid failure: " | |
1115 "lasterror = %d \n", GetLastError()); | |
1116 } | |
1117 return NULL; | |
1118 } | |
1119 | |
1120 // initialize the ace data for everybody else. | |
1121 aces[2].pSid = everybodySid; | |
1122 aces[2].mask = emask; | |
1123 | |
1124 // create a security attributes structure with access control | |
1125 // entries as initialized above. | |
1126 LPSECURITY_ATTRIBUTES lpSA = make_security_attr(aces, 3); | |
1127 FREE_C_HEAP_ARRAY(char, aces[0].pSid); | |
1128 FreeSid(everybodySid); | |
1129 FreeSid(administratorsSid); | |
1130 return(lpSA); | |
1131 } | |
1132 | |
1133 | |
1134 // method to create the security attributes structure for restricting | |
1135 // access to the user temporary directory. | |
1136 // | |
1137 // the caller must free the resources associated with the security | |
1138 // attributes structure created by this method by calling the | |
1139 // free_security_attr() method. | |
1140 // | |
1141 static LPSECURITY_ATTRIBUTES make_tmpdir_security_attr() { | |
1142 | |
1143 // create full access rights for the user/owner of the directory | |
1144 // and read-only access rights for everybody else. This is | |
1145 // effectively equivalent to UNIX 755 permissions on a directory. | |
1146 // | |
1147 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_ALL_ACCESS; | |
1148 DWORD emask = GENERIC_READ | FILE_LIST_DIRECTORY | FILE_TRAVERSE; | |
1149 DWORD amask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS; | |
1150 | |
1151 return make_user_everybody_admin_security_attr(umask, emask, amask); | |
1152 } | |
1153 | |
1154 // method to create the security attributes structure for restricting | |
1155 // access to the shared memory backing store file. | |
1156 // | |
1157 // the caller must free the resources associated with the security | |
1158 // attributes structure created by this method by calling the | |
1159 // free_security_attr() method. | |
1160 // | |
1161 static LPSECURITY_ATTRIBUTES make_file_security_attr() { | |
1162 | |
1163 // create extensive access rights for the user/owner of the file | |
1164 // and attribute read-only access rights for everybody else. This | |
1165 // is effectively equivalent to UNIX 600 permissions on a file. | |
1166 // | |
1167 DWORD umask = STANDARD_RIGHTS_ALL | FILE_ALL_ACCESS; | |
1168 DWORD emask = STANDARD_RIGHTS_READ | FILE_READ_ATTRIBUTES | | |
1169 FILE_READ_EA | 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 name shared memory file mapping object. | |
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_smo_security_attr() { | |
1183 | |
1184 // create extensive access rights for the user/owner of the shared | |
1185 // memory object and attribute read-only access rights for everybody | |
1186 // else. This is effectively equivalent to UNIX 600 permissions on | |
1187 // on the shared memory object. | |
1188 // | |
1189 DWORD umask = STANDARD_RIGHTS_REQUIRED | FILE_MAP_ALL_ACCESS; | |
1190 DWORD emask = STANDARD_RIGHTS_READ; // attributes only | |
1191 DWORD amask = STANDARD_RIGHTS_ALL | FILE_MAP_ALL_ACCESS; | |
1192 | |
1193 return make_user_everybody_admin_security_attr(umask, emask, amask); | |
1194 } | |
1195 | |
1196 // make the user specific temporary directory | |
1197 // | |
1198 static bool make_user_tmp_dir(const char* dirname) { | |
1199 | |
1200 | |
1201 LPSECURITY_ATTRIBUTES pDirSA = make_tmpdir_security_attr(); | |
1202 if (pDirSA == NULL) { | |
1203 return false; | |
1204 } | |
1205 | |
1206 | |
1207 // create the directory with the given security attributes | |
1208 if (!CreateDirectory(dirname, pDirSA)) { | |
1209 DWORD lasterror = GetLastError(); | |
1210 if (lasterror == ERROR_ALREADY_EXISTS) { | |
1211 // The directory already exists and was probably created by another | |
1212 // JVM instance. However, this could also be the result of a | |
1213 // deliberate symlink. Verify that the existing directory is safe. | |
1214 // | |
1215 if (!is_directory_secure(dirname)) { | |
1216 // directory is not secure | |
1217 if (PrintMiscellaneous && Verbose) { | |
1218 warning("%s directory is insecure\n", dirname); | |
1219 } | |
1220 return false; | |
1221 } | |
1222 // The administrator should be able to delete this directory. | |
1223 // But the directory created by previous version of JVM may not | |
1224 // have permission for administrators to delete this directory. | |
1225 // So add full permission to the administrator. Also setting new | |
1226 // DACLs might fix the corrupted the DACLs. | |
1227 SECURITY_INFORMATION secInfo = DACL_SECURITY_INFORMATION; | |
1228 if (!SetFileSecurity(dirname, secInfo, pDirSA->lpSecurityDescriptor)) { | |
1229 if (PrintMiscellaneous && Verbose) { | |
1230 lasterror = GetLastError(); | |
1231 warning("SetFileSecurity failed for %s directory. lasterror %d \n", | |
1232 dirname, lasterror); | |
1233 } | |
1234 } | |
1235 } | |
1236 else { | |
1237 if (PrintMiscellaneous && Verbose) { | |
1238 warning("CreateDirectory failed: %d\n", GetLastError()); | |
1239 } | |
1240 return false; | |
1241 } | |
1242 } | |
1243 | |
1244 // free the security attributes structure | |
1245 free_security_attr(pDirSA); | |
1246 | |
1247 return true; | |
1248 } | |
1249 | |
1250 // create the shared memory resources | |
1251 // | |
1252 // This function creates the shared memory resources. This includes | |
1253 // the backing store file and the file mapping shared memory object. | |
1254 // | |
1255 static HANDLE create_sharedmem_resources(const char* dirname, const char* filename, const char* objectname, size_t size) { | |
1256 | |
1257 HANDLE fh = INVALID_HANDLE_VALUE; | |
1258 HANDLE fmh = NULL; | |
1259 | |
1260 | |
1261 // create the security attributes for the backing store file | |
1262 LPSECURITY_ATTRIBUTES lpFileSA = make_file_security_attr(); | |
1263 if (lpFileSA == NULL) { | |
1264 return NULL; | |
1265 } | |
1266 | |
1267 // create the security attributes for the shared memory object | |
1268 LPSECURITY_ATTRIBUTES lpSmoSA = make_smo_security_attr(); | |
1269 if (lpSmoSA == NULL) { | |
1270 free_security_attr(lpFileSA); | |
1271 return NULL; | |
1272 } | |
1273 | |
1274 // create the user temporary directory | |
1275 if (!make_user_tmp_dir(dirname)) { | |
1276 // could not make/find the directory or the found directory | |
1277 // was not secure | |
1278 return NULL; | |
1279 } | |
1280 | |
1281 // Create the file - the FILE_FLAG_DELETE_ON_CLOSE flag allows the | |
1282 // file to be deleted by the last process that closes its handle to | |
1283 // the file. This is important as the apis do not allow a terminating | |
1284 // JVM being monitored by another process to remove the file name. | |
1285 // | |
1286 // the FILE_SHARE_DELETE share mode is valid only in winnt | |
1287 // | |
1288 fh = CreateFile( | |
1289 filename, /* LPCTSTR file name */ | |
1290 | |
1291 GENERIC_READ|GENERIC_WRITE, /* DWORD desired access */ | |
1292 | |
1293 (os::win32::is_nt() ? FILE_SHARE_DELETE : 0)| | |
1294 FILE_SHARE_READ, /* DWORD share mode, future READONLY | |
1295 * open operations allowed | |
1296 */ | |
1297 lpFileSA, /* LPSECURITY security attributes */ | |
1298 CREATE_ALWAYS, /* DWORD creation disposition | |
1299 * create file, if it already | |
1300 * exists, overwrite it. | |
1301 */ | |
1302 FILE_FLAG_DELETE_ON_CLOSE, /* DWORD flags and attributes */ | |
1303 | |
1304 NULL); /* HANDLE template file access */ | |
1305 | |
1306 free_security_attr(lpFileSA); | |
1307 | |
1308 if (fh == INVALID_HANDLE_VALUE) { | |
1309 DWORD lasterror = GetLastError(); | |
1310 if (PrintMiscellaneous && Verbose) { | |
1311 warning("could not create file %s: %d\n", filename, lasterror); | |
1312 } | |
1313 return NULL; | |
1314 } | |
1315 | |
1316 // try to create the file mapping | |
1317 fmh = create_file_mapping(objectname, fh, lpSmoSA, size); | |
1318 | |
1319 free_security_attr(lpSmoSA); | |
1320 | |
1321 if (fmh == NULL) { | |
1322 // closing the file handle here will decrement the reference count | |
1323 // on the file. When all processes accessing the file close their | |
1324 // handle to it, the reference count will decrement to 0 and the | |
1325 // OS will delete the file. These semantics are requested by the | |
1326 // FILE_FLAG_DELETE_ON_CLOSE flag in CreateFile call above. | |
1327 CloseHandle(fh); | |
1328 fh = NULL; | |
1329 return NULL; | |
1330 } | |
1331 | |
1332 // the file has been successfully created and the file mapping | |
1333 // object has been created. | |
1334 sharedmem_fileHandle = fh; | |
1335 sharedmem_fileName = strdup(filename); | |
1336 | |
1337 return fmh; | |
1338 } | |
1339 | |
1340 // open the shared memory object for the given vmid. | |
1341 // | |
1342 static HANDLE open_sharedmem_object(const char* objectname, DWORD ofm_access, TRAPS) { | |
1343 | |
1344 HANDLE fmh; | |
1345 | |
1346 // open the file mapping with the requested mode | |
1347 fmh = OpenFileMapping( | |
1348 ofm_access, /* DWORD access mode */ | |
1349 FALSE, /* BOOL inherit flag - Do not allow inherit */ | |
1350 objectname); /* name for object */ | |
1351 | |
1352 if (fmh == NULL) { | |
1353 if (PrintMiscellaneous && Verbose) { | |
1354 warning("OpenFileMapping failed for shared memory object %s:" | |
1355 " lasterror = %d\n", objectname, GetLastError()); | |
1356 } | |
1357 THROW_MSG_(vmSymbols::java_lang_Exception(), | |
1358 "Could not open PerfMemory", INVALID_HANDLE_VALUE); | |
1359 } | |
1360 | |
1361 return fmh;; | |
1362 } | |
1363 | |
1364 // create a named shared memory region | |
1365 // | |
1366 // On Win32, a named shared memory object has a name space that | |
1367 // is independent of the file system name space. Shared memory object, | |
1368 // or more precisely, file mapping objects, provide no mechanism to | |
1369 // inquire the size of the memory region. There is also no api to | |
1370 // enumerate the memory regions for various processes. | |
1371 // | |
1372 // This implementation utilizes the shared memory name space in parallel | |
1373 // with the file system name space. This allows us to determine the | |
1374 // size of the shared memory region from the size of the file and it | |
1375 // allows us to provide a common, file system based name space for | |
1376 // shared memory across platforms. | |
1377 // | |
1378 static char* mapping_create_shared(size_t size) { | |
1379 | |
1380 void *mapAddress; | |
1381 int vmid = os::current_process_id(); | |
1382 | |
1383 // get the name of the user associated with this process | |
1384 char* user = get_user_name(); | |
1385 | |
1386 if (user == NULL) { | |
1387 return NULL; | |
1388 } | |
1389 | |
1390 // construct the name of the user specific temporary directory | |
1391 char* dirname = get_user_tmp_dir(user); | |
1392 | |
1393 // check that the file system is secure - i.e. it supports ACLs. | |
1394 if (!is_filesystem_secure(dirname)) { | |
1395 return NULL; | |
1396 } | |
1397 | |
1398 // create the names of the backing store files and for the | |
1399 // share memory object. | |
1400 // | |
1401 char* filename = get_sharedmem_filename(dirname, vmid); | |
1402 char* objectname = get_sharedmem_objectname(user, vmid); | |
1403 | |
1404 // cleanup any stale shared memory resources | |
1405 cleanup_sharedmem_resources(dirname); | |
1406 | |
1407 assert(((size != 0) && (size % os::vm_page_size() == 0)), | |
1408 "unexpected PerfMemry region size"); | |
1409 | |
1410 FREE_C_HEAP_ARRAY(char, user); | |
1411 | |
1412 // create the shared memory resources | |
1413 sharedmem_fileMapHandle = | |
1414 create_sharedmem_resources(dirname, filename, objectname, size); | |
1415 | |
1416 FREE_C_HEAP_ARRAY(char, filename); | |
1417 FREE_C_HEAP_ARRAY(char, objectname); | |
1418 FREE_C_HEAP_ARRAY(char, dirname); | |
1419 | |
1420 if (sharedmem_fileMapHandle == NULL) { | |
1421 return NULL; | |
1422 } | |
1423 | |
1424 // map the file into the address space | |
1425 mapAddress = MapViewOfFile( | |
1426 sharedmem_fileMapHandle, /* HANDLE = file mapping object */ | |
1427 FILE_MAP_ALL_ACCESS, /* DWORD access flags */ | |
1428 0, /* DWORD High word of offset */ | |
1429 0, /* DWORD Low word of offset */ | |
1430 (DWORD)size); /* DWORD Number of bytes to map */ | |
1431 | |
1432 if (mapAddress == NULL) { | |
1433 if (PrintMiscellaneous && Verbose) { | |
1434 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError()); | |
1435 } | |
1436 CloseHandle(sharedmem_fileMapHandle); | |
1437 sharedmem_fileMapHandle = NULL; | |
1438 return NULL; | |
1439 } | |
1440 | |
1441 // clear the shared memory region | |
1442 (void)memset(mapAddress, '\0', size); | |
1443 | |
1444 return (char*) mapAddress; | |
1445 } | |
1446 | |
1447 // this method deletes the file mapping object. | |
1448 // | |
1449 static void delete_file_mapping(char* addr, size_t size) { | |
1450 | |
1451 // cleanup the persistent shared memory resources. since DestroyJavaVM does | |
1452 // not support unloading of the JVM, unmapping of the memory resource is not | |
1453 // performed. The memory will be reclaimed by the OS upon termination of all | |
1454 // processes mapping the resource. The file mapping handle and the file | |
1455 // handle are closed here to expedite the remove of the file by the OS. The | |
1456 // file is not removed directly because it was created with | |
1457 // FILE_FLAG_DELETE_ON_CLOSE semantics and any attempt to remove it would | |
1458 // be unsuccessful. | |
1459 | |
1460 // close the fileMapHandle. the file mapping will still be retained | |
1461 // by the OS as long as any other JVM processes has an open file mapping | |
1462 // handle or a mapped view of the file. | |
1463 // | |
1464 if (sharedmem_fileMapHandle != NULL) { | |
1465 CloseHandle(sharedmem_fileMapHandle); | |
1466 sharedmem_fileMapHandle = NULL; | |
1467 } | |
1468 | |
1469 // close the file handle. This will decrement the reference count on the | |
1470 // backing store file. When the reference count decrements to 0, the OS | |
1471 // will delete the file. These semantics apply because the file was | |
1472 // created with the FILE_FLAG_DELETE_ON_CLOSE flag. | |
1473 // | |
1474 if (sharedmem_fileHandle != INVALID_HANDLE_VALUE) { | |
1475 CloseHandle(sharedmem_fileHandle); | |
1476 sharedmem_fileHandle = INVALID_HANDLE_VALUE; | |
1477 } | |
1478 } | |
1479 | |
1480 // this method determines the size of the shared memory file | |
1481 // | |
1482 static size_t sharedmem_filesize(const char* filename, TRAPS) { | |
1483 | |
1484 struct stat statbuf; | |
1485 | |
1486 // get the file size | |
1487 // | |
1488 // on win95/98/me, _stat returns a file size of 0 bytes, but on | |
1489 // winnt/2k the appropriate file size is returned. support for | |
1490 // the sharable aspects of performance counters was abandonded | |
1491 // on the non-nt win32 platforms due to this and other api | |
1492 // inconsistencies | |
1493 // | |
1494 if (::stat(filename, &statbuf) == OS_ERR) { | |
1495 if (PrintMiscellaneous && Verbose) { | |
1496 warning("stat %s failed: %s\n", filename, strerror(errno)); | |
1497 } | |
1498 THROW_MSG_0(vmSymbols::java_io_IOException(), | |
1499 "Could not determine PerfMemory size"); | |
1500 } | |
1501 | |
1502 if ((statbuf.st_size == 0) || (statbuf.st_size % os::vm_page_size() != 0)) { | |
1503 if (PrintMiscellaneous && Verbose) { | |
1504 warning("unexpected file size: size = " SIZE_FORMAT "\n", | |
1505 statbuf.st_size); | |
1506 } | |
1507 THROW_MSG_0(vmSymbols::java_lang_Exception(), | |
1508 "Invalid PerfMemory size"); | |
1509 } | |
1510 | |
1511 return statbuf.st_size; | |
1512 } | |
1513 | |
1514 // this method opens a file mapping object and maps the object | |
1515 // into the address space of the process | |
1516 // | |
1517 static void open_file_mapping(const char* user, int vmid, | |
1518 PerfMemory::PerfMemoryMode mode, | |
1519 char** addrp, size_t* sizep, TRAPS) { | |
1520 | |
1521 ResourceMark rm; | |
1522 | |
1523 void *mapAddress = 0; | |
1524 size_t size; | |
1525 HANDLE fmh; | |
1526 DWORD ofm_access; | |
1527 DWORD mv_access; | |
1528 const char* luser = NULL; | |
1529 | |
1530 if (mode == PerfMemory::PERF_MODE_RO) { | |
1531 ofm_access = FILE_MAP_READ; | |
1532 mv_access = FILE_MAP_READ; | |
1533 } | |
1534 else if (mode == PerfMemory::PERF_MODE_RW) { | |
1535 #ifdef LATER | |
1536 ofm_access = FILE_MAP_READ | FILE_MAP_WRITE; | |
1537 mv_access = FILE_MAP_READ | FILE_MAP_WRITE; | |
1538 #else | |
1539 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
1540 "Unsupported access mode"); | |
1541 #endif | |
1542 } | |
1543 else { | |
1544 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
1545 "Illegal access mode"); | |
1546 } | |
1547 | |
1548 // if a user name wasn't specified, then find the user name for | |
1549 // the owner of the target vm. | |
1550 if (user == NULL || strlen(user) == 0) { | |
1551 luser = get_user_name(vmid); | |
1552 } | |
1553 else { | |
1554 luser = user; | |
1555 } | |
1556 | |
1557 if (luser == NULL) { | |
1558 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
1559 "Could not map vmid to user name"); | |
1560 } | |
1561 | |
1562 // get the names for the resources for the target vm | |
1563 char* dirname = get_user_tmp_dir(luser); | |
1564 | |
1565 // since we don't follow symbolic links when creating the backing | |
1566 // store file, we also don't following them when attaching | |
1567 // | |
1568 if (!is_directory_secure(dirname)) { | |
1569 FREE_C_HEAP_ARRAY(char, dirname); | |
1570 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
1571 "Process not found"); | |
1572 } | |
1573 | |
1574 char* filename = get_sharedmem_filename(dirname, vmid); | |
1575 char* objectname = get_sharedmem_objectname(luser, vmid); | |
1576 | |
1577 // copy heap memory to resource memory. the objectname and | |
1578 // filename are passed to methods that may throw exceptions. | |
1579 // using resource arrays for these names prevents the leaks | |
1580 // that would otherwise occur. | |
1581 // | |
1582 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1); | |
1583 char* robjectname = NEW_RESOURCE_ARRAY(char, strlen(objectname) + 1); | |
1584 strcpy(rfilename, filename); | |
1585 strcpy(robjectname, objectname); | |
1586 | |
1587 // free the c heap resources that are no longer needed | |
1588 if (luser != user) FREE_C_HEAP_ARRAY(char, luser); | |
1589 FREE_C_HEAP_ARRAY(char, dirname); | |
1590 FREE_C_HEAP_ARRAY(char, filename); | |
1591 FREE_C_HEAP_ARRAY(char, objectname); | |
1592 | |
1593 if (*sizep == 0) { | |
1594 size = sharedmem_filesize(rfilename, CHECK); | |
1595 assert(size != 0, "unexpected size"); | |
1596 } | |
1597 | |
1598 // Open the file mapping object with the given name | |
1599 fmh = open_sharedmem_object(robjectname, ofm_access, CHECK); | |
1600 | |
1601 assert(fmh != INVALID_HANDLE_VALUE, "unexpected handle value"); | |
1602 | |
1603 // map the entire file into the address space | |
1604 mapAddress = MapViewOfFile( | |
1605 fmh, /* HANDLE Handle of file mapping object */ | |
1606 mv_access, /* DWORD access flags */ | |
1607 0, /* DWORD High word of offset */ | |
1608 0, /* DWORD Low word of offset */ | |
1609 size); /* DWORD Number of bytes to map */ | |
1610 | |
1611 if (mapAddress == NULL) { | |
1612 if (PrintMiscellaneous && Verbose) { | |
1613 warning("MapViewOfFile failed, lasterror = %d\n", GetLastError()); | |
1614 } | |
1615 CloseHandle(fmh); | |
1616 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(), | |
1617 "Could not map PerfMemory"); | |
1618 } | |
1619 | |
1620 *addrp = (char*)mapAddress; | |
1621 *sizep = size; | |
1622 | |
1623 // File mapping object can be closed at this time without | |
1624 // invalidating the mapped view of the file | |
1625 CloseHandle(fmh); | |
1626 | |
1627 if (PerfTraceMemOps) { | |
1628 tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at " | |
1629 INTPTR_FORMAT "\n", size, vmid, mapAddress); | |
1630 } | |
1631 } | |
1632 | |
1633 // this method unmaps the the mapped view of the the | |
1634 // file mapping object. | |
1635 // | |
1636 static void remove_file_mapping(char* addr) { | |
1637 | |
1638 // the file mapping object was closed in open_file_mapping() | |
1639 // after the file map view was created. We only need to | |
1640 // unmap the file view here. | |
1641 UnmapViewOfFile(addr); | |
1642 } | |
1643 | |
1644 // create the PerfData memory region in shared memory. | |
1645 static char* create_shared_memory(size_t size) { | |
1646 | |
1647 return mapping_create_shared(size); | |
1648 } | |
1649 | |
1650 // release a named, shared memory region | |
1651 // | |
1652 void delete_shared_memory(char* addr, size_t size) { | |
1653 | |
1654 delete_file_mapping(addr, size); | |
1655 } | |
1656 | |
1657 | |
1658 | |
1659 | |
1660 // create the PerfData memory region | |
1661 // | |
1662 // This method creates the memory region used to store performance | |
1663 // data for the JVM. The memory may be created in standard or | |
1664 // shared memory. | |
1665 // | |
1666 void PerfMemory::create_memory_region(size_t size) { | |
1667 | |
1668 if (PerfDisableSharedMem || !os::win32::is_nt()) { | |
1669 // do not share the memory for the performance data. | |
1670 PerfDisableSharedMem = true; | |
1671 _start = create_standard_memory(size); | |
1672 } | |
1673 else { | |
1674 _start = create_shared_memory(size); | |
1675 if (_start == NULL) { | |
1676 | |
1677 // creation of the shared memory region failed, attempt | |
1678 // to create a contiguous, non-shared memory region instead. | |
1679 // | |
1680 if (PrintMiscellaneous && Verbose) { | |
1681 warning("Reverting to non-shared PerfMemory region.\n"); | |
1682 } | |
1683 PerfDisableSharedMem = true; | |
1684 _start = create_standard_memory(size); | |
1685 } | |
1686 } | |
1687 | |
1688 if (_start != NULL) _capacity = size; | |
1689 | |
1690 } | |
1691 | |
1692 // delete the PerfData memory region | |
1693 // | |
1694 // This method deletes the memory region used to store performance | |
1695 // data for the JVM. The memory region indicated by the <address, size> | |
1696 // tuple will be inaccessible after a call to this method. | |
1697 // | |
1698 void PerfMemory::delete_memory_region() { | |
1699 | |
1700 assert((start() != NULL && capacity() > 0), "verify proper state"); | |
1701 | |
1702 // If user specifies PerfDataSaveFile, it will save the performance data | |
1703 // to the specified file name no matter whether PerfDataSaveToFile is specified | |
1704 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag | |
1705 // -XX:+PerfDataSaveToFile. | |
1706 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) { | |
1707 save_memory_to_file(start(), capacity()); | |
1708 } | |
1709 | |
1710 if (PerfDisableSharedMem) { | |
1711 delete_standard_memory(start(), capacity()); | |
1712 } | |
1713 else { | |
1714 delete_shared_memory(start(), capacity()); | |
1715 } | |
1716 } | |
1717 | |
1718 // attach to the PerfData memory region for another JVM | |
1719 // | |
1720 // This method returns an <address, size> tuple that points to | |
1721 // a memory buffer that is kept reasonably synchronized with | |
1722 // the PerfData memory region for the indicated JVM. This | |
1723 // buffer may be kept in synchronization via shared memory | |
1724 // or some other mechanism that keeps the buffer updated. | |
1725 // | |
1726 // If the JVM chooses not to support the attachability feature, | |
1727 // this method should throw an UnsupportedOperation exception. | |
1728 // | |
1729 // This implementation utilizes named shared memory to map | |
1730 // the indicated process's PerfData memory region into this JVMs | |
1731 // address space. | |
1732 // | |
1733 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, | |
1734 char** addrp, size_t* sizep, TRAPS) { | |
1735 | |
1736 if (vmid == 0 || vmid == os::current_process_id()) { | |
1737 *addrp = start(); | |
1738 *sizep = capacity(); | |
1739 return; | |
1740 } | |
1741 | |
1742 open_file_mapping(user, vmid, mode, addrp, sizep, CHECK); | |
1743 } | |
1744 | |
1745 // detach from the PerfData memory region of another JVM | |
1746 // | |
1747 // This method detaches the PerfData memory region of another | |
1748 // JVM, specified as an <address, size> tuple of a buffer | |
1749 // in this process's address space. This method may perform | |
1750 // arbitrary actions to accomplish the detachment. The memory | |
1751 // region specified by <address, size> will be inaccessible after | |
1752 // a call to this method. | |
1753 // | |
1754 // If the JVM chooses not to support the attachability feature, | |
1755 // this method should throw an UnsupportedOperation exception. | |
1756 // | |
1757 // This implementation utilizes named shared memory to detach | |
1758 // the indicated process's PerfData memory region from this | |
1759 // process's address space. | |
1760 // | |
1761 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) { | |
1762 | |
1763 assert(addr != 0, "address sanity check"); | |
1764 assert(bytes > 0, "capacity sanity check"); | |
1765 | |
1766 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) { | |
1767 // prevent accidental detachment of this process's PerfMemory region | |
1768 return; | |
1769 } | |
1770 | |
1771 remove_file_mapping(addr); | |
1772 } | |
1773 | |
1774 char* PerfMemory::backing_store_filename() { | |
1775 return sharedmem_fileName; | |
1776 } |