Mercurial > hg > truffle
annotate src/os/linux/vm/perfMemory_linux.cpp @ 1865:1c352af0135d
6763959: java.util.concurrent.locks.LockSupport.parkUntil(0) blocks forever
Summary: Absolute time 0 needs to return immediately.
Reviewed-by: phh, dcubed, dholmes
author | acorn |
---|---|
date | Mon, 04 Oct 2010 13:11:10 -0400 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 2001, 2006, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_perfMemory_linux.cpp.incl" | |
27 | |
28 // put OS-includes here | |
29 # include <sys/types.h> | |
30 # include <sys/mman.h> | |
31 # include <errno.h> | |
32 # include <stdio.h> | |
33 # include <unistd.h> | |
34 # include <sys/stat.h> | |
35 # include <signal.h> | |
36 # include <pwd.h> | |
37 | |
38 static char* backing_store_file_name = NULL; // name of the backing store | |
39 // file, if successfully created. | |
40 | |
41 // Standard Memory Implementation Details | |
42 | |
43 // create the PerfData memory region in standard memory. | |
44 // | |
45 static char* create_standard_memory(size_t size) { | |
46 | |
47 // allocate an aligned chuck of memory | |
48 char* mapAddress = os::reserve_memory(size); | |
49 | |
50 if (mapAddress == NULL) { | |
51 return NULL; | |
52 } | |
53 | |
54 // commit memory | |
55 if (!os::commit_memory(mapAddress, size)) { | |
56 if (PrintMiscellaneous && Verbose) { | |
57 warning("Could not commit PerfData memory\n"); | |
58 } | |
59 os::release_memory(mapAddress, size); | |
60 return NULL; | |
61 } | |
62 | |
63 return mapAddress; | |
64 } | |
65 | |
66 // delete the PerfData memory region | |
67 // | |
68 static void delete_standard_memory(char* addr, size_t size) { | |
69 | |
70 // there are no persistent external resources to cleanup for standard | |
71 // memory. since DestroyJavaVM does not support unloading of the JVM, | |
72 // cleanup of the memory resource is not performed. The memory will be | |
73 // reclaimed by the OS upon termination of the process. | |
74 // | |
75 return; | |
76 } | |
77 | |
78 // save the specified memory region to the given file | |
79 // | |
80 // Note: this function might be called from signal handler (by os::abort()), | |
81 // don't allocate heap memory. | |
82 // | |
83 static void save_memory_to_file(char* addr, size_t size) { | |
84 | |
85 const char* destfile = PerfMemory::get_perfdata_file_path(); | |
86 assert(destfile[0] != '\0', "invalid PerfData file path"); | |
87 | |
88 int result; | |
89 | |
90 RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE), | |
91 result);; | |
92 if (result == OS_ERR) { | |
93 if (PrintMiscellaneous && Verbose) { | |
94 warning("Could not create Perfdata save file: %s: %s\n", | |
95 destfile, strerror(errno)); | |
96 } | |
97 } else { | |
98 int fd = result; | |
99 | |
100 for (size_t remaining = size; remaining > 0;) { | |
101 | |
102 RESTARTABLE(::write(fd, addr, remaining), result); | |
103 if (result == 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)result; | |
112 addr += result; | |
113 } | |
114 | |
115 RESTARTABLE(::close(fd), result); | |
116 if (PrintMiscellaneous && Verbose) { | |
117 if (result == OS_ERR) { | |
118 warning("Could not close %s: %s\n", destfile, strerror(errno)); | |
119 } | |
120 } | |
121 } | |
122 FREE_C_HEAP_ARRAY(char, destfile); | |
123 } | |
124 | |
125 | |
126 // Shared Memory Implementation Details | |
127 | |
128 // Note: the solaris and linux shared memory implementation uses the mmap | |
129 // interface with a backing store file to implement named shared memory. | |
130 // Using the file system as the name space for shared memory allows a | |
131 // common name space to be supported across a variety of platforms. It | |
132 // also provides a name space that Java applications can deal with through | |
133 // simple file apis. | |
134 // | |
135 // The solaris and linux implementations store the backing store file in | |
136 // a user specific temporary directory located in the /tmp file system, | |
137 // which is always a local file system and is sometimes a RAM based file | |
138 // system. | |
139 | |
140 // return the user specific temporary directory name. | |
141 // | |
142 // the caller is expected to free the allocated memory. | |
143 // | |
144 static char* get_user_tmp_dir(const char* user) { | |
145 | |
146 const char* tmpdir = os::get_temp_directory(); | |
147 const char* perfdir = PERFDATA_NAME; | |
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148 size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3; |
0 | 149 char* dirname = NEW_C_HEAP_ARRAY(char, nbytes); |
150 | |
151 // construct the path name to user specific tmp directory | |
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152 snprintf(dirname, nbytes, "%s/%s_%s", tmpdir, perfdir, user); |
0 | 153 |
154 return dirname; | |
155 } | |
156 | |
157 // convert the given file name into a process id. if the file | |
158 // does not meet the file naming constraints, return 0. | |
159 // | |
160 static pid_t filename_to_pid(const char* filename) { | |
161 | |
162 // a filename that doesn't begin with a digit is not a | |
163 // candidate for conversion. | |
164 // | |
165 if (!isdigit(*filename)) { | |
166 return 0; | |
167 } | |
168 | |
169 // check if file name can be converted to an integer without | |
170 // any leftover characters. | |
171 // | |
172 char* remainder = NULL; | |
173 errno = 0; | |
174 pid_t pid = (pid_t)strtol(filename, &remainder, 10); | |
175 | |
176 if (errno != 0) { | |
177 return 0; | |
178 } | |
179 | |
180 // check for left over characters. If any, then the filename is | |
181 // not a candidate for conversion. | |
182 // | |
183 if (remainder != NULL && *remainder != '\0') { | |
184 return 0; | |
185 } | |
186 | |
187 // successful conversion, return the pid | |
188 return pid; | |
189 } | |
190 | |
191 | |
192 // check if the given path is considered a secure directory for | |
193 // the backing store files. Returns true if the directory exists | |
194 // and is considered a secure location. Returns false if the path | |
605 | 195 // is a symbolic link or if an error occurred. |
0 | 196 // |
197 static bool is_directory_secure(const char* path) { | |
198 struct stat statbuf; | |
199 int result = 0; | |
200 | |
201 RESTARTABLE(::lstat(path, &statbuf), result); | |
202 if (result == OS_ERR) { | |
203 return false; | |
204 } | |
205 | |
206 // the path exists, now check it's mode | |
207 if (S_ISLNK(statbuf.st_mode) || !S_ISDIR(statbuf.st_mode)) { | |
208 // the path represents a link or some non-directory file type, | |
209 // which is not what we expected. declare it insecure. | |
210 // | |
211 return false; | |
212 } | |
213 else { | |
214 // we have an existing directory, check if the permissions are safe. | |
215 // | |
216 if ((statbuf.st_mode & (S_IWGRP|S_IWOTH)) != 0) { | |
217 // the directory is open for writing and could be subjected | |
218 // to a symlnk attack. declare it insecure. | |
219 // | |
220 return false; | |
221 } | |
222 } | |
223 return true; | |
224 } | |
225 | |
226 | |
227 // return the user name for the given user id | |
228 // | |
229 // the caller is expected to free the allocated memory. | |
230 // | |
231 static char* get_user_name(uid_t uid) { | |
232 | |
233 struct passwd pwent; | |
234 | |
235 // determine the max pwbuf size from sysconf, and hardcode | |
236 // a default if this not available through sysconf. | |
237 // | |
238 long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX); | |
239 if (bufsize == -1) | |
240 bufsize = 1024; | |
241 | |
242 char* pwbuf = NEW_C_HEAP_ARRAY(char, bufsize); | |
243 | |
244 // POSIX interface to getpwuid_r is used on LINUX | |
245 struct passwd* p; | |
246 int result = getpwuid_r(uid, &pwent, pwbuf, (size_t)bufsize, &p); | |
247 | |
248 if (result != 0 || p == NULL || p->pw_name == NULL || *(p->pw_name) == '\0') { | |
249 if (PrintMiscellaneous && Verbose) { | |
250 if (result != 0) { | |
251 warning("Could not retrieve passwd entry: %s\n", | |
252 strerror(result)); | |
253 } | |
254 else if (p == NULL) { | |
255 // this check is added to protect against an observed problem | |
256 // with getpwuid_r() on RedHat 9 where getpwuid_r returns 0, | |
257 // indicating success, but has p == NULL. This was observed when | |
258 // inserting a file descriptor exhaustion fault prior to the call | |
259 // getpwuid_r() call. In this case, error is set to the appropriate | |
260 // error condition, but this is undocumented behavior. This check | |
261 // is safe under any condition, but the use of errno in the output | |
262 // message may result in an erroneous message. | |
263 // Bug Id 89052 was opened with RedHat. | |
264 // | |
265 warning("Could not retrieve passwd entry: %s\n", | |
266 strerror(errno)); | |
267 } | |
268 else { | |
269 warning("Could not determine user name: %s\n", | |
270 p->pw_name == NULL ? "pw_name = NULL" : | |
271 "pw_name zero length"); | |
272 } | |
273 } | |
274 FREE_C_HEAP_ARRAY(char, pwbuf); | |
275 return NULL; | |
276 } | |
277 | |
278 char* user_name = NEW_C_HEAP_ARRAY(char, strlen(p->pw_name) + 1); | |
279 strcpy(user_name, p->pw_name); | |
280 | |
281 FREE_C_HEAP_ARRAY(char, pwbuf); | |
282 return user_name; | |
283 } | |
284 | |
285 // return the name of the user that owns the process identified by vmid. | |
286 // | |
287 // This method uses a slow directory search algorithm to find the backing | |
288 // store file for the specified vmid and returns the user name, as determined | |
289 // by the user name suffix of the hsperfdata_<username> directory name. | |
290 // | |
291 // the caller is expected to free the allocated memory. | |
292 // | |
293 static char* get_user_name_slow(int vmid, TRAPS) { | |
294 | |
295 // short circuit the directory search if the process doesn't even exist. | |
296 if (kill(vmid, 0) == OS_ERR) { | |
297 if (errno == ESRCH) { | |
298 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), | |
299 "Process not found"); | |
300 } | |
301 else /* EPERM */ { | |
302 THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno)); | |
303 } | |
304 } | |
305 | |
306 // directory search | |
307 char* oldest_user = NULL; | |
308 time_t oldest_ctime = 0; | |
309 | |
310 const char* tmpdirname = os::get_temp_directory(); | |
311 | |
312 DIR* tmpdirp = os::opendir(tmpdirname); | |
313 | |
314 if (tmpdirp == NULL) { | |
315 return NULL; | |
316 } | |
317 | |
318 // for each entry in the directory that matches the pattern hsperfdata_*, | |
319 // open the directory and check if the file for the given vmid exists. | |
320 // The file with the expected name and the latest creation date is used | |
321 // to determine the user name for the process id. | |
322 // | |
323 struct dirent* dentry; | |
324 char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname)); | |
325 errno = 0; | |
326 while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) { | |
327 | |
328 // check if the directory entry is a hsperfdata file | |
329 if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) { | |
330 continue; | |
331 } | |
332 | |
333 char* usrdir_name = NEW_C_HEAP_ARRAY(char, | |
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334 strlen(tmpdirname) + strlen(dentry->d_name) + 2); |
0 | 335 strcpy(usrdir_name, tmpdirname); |
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336 strcat(usrdir_name, "/"); |
0 | 337 strcat(usrdir_name, dentry->d_name); |
338 | |
339 DIR* subdirp = os::opendir(usrdir_name); | |
340 | |
341 if (subdirp == NULL) { | |
342 FREE_C_HEAP_ARRAY(char, usrdir_name); | |
343 continue; | |
344 } | |
345 | |
346 // Since we don't create the backing store files in directories | |
347 // pointed to by symbolic links, we also don't follow them when | |
348 // looking for the files. We check for a symbolic link after the | |
349 // call to opendir in order to eliminate a small window where the | |
350 // symlink can be exploited. | |
351 // | |
352 if (!is_directory_secure(usrdir_name)) { | |
353 FREE_C_HEAP_ARRAY(char, usrdir_name); | |
354 os::closedir(subdirp); | |
355 continue; | |
356 } | |
357 | |
358 struct dirent* udentry; | |
359 char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name)); | |
360 errno = 0; | |
361 while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) { | |
362 | |
363 if (filename_to_pid(udentry->d_name) == vmid) { | |
364 struct stat statbuf; | |
365 int result; | |
366 | |
367 char* filename = NEW_C_HEAP_ARRAY(char, | |
368 strlen(usrdir_name) + strlen(udentry->d_name) + 2); | |
369 | |
370 strcpy(filename, usrdir_name); | |
371 strcat(filename, "/"); | |
372 strcat(filename, udentry->d_name); | |
373 | |
374 // don't follow symbolic links for the file | |
375 RESTARTABLE(::lstat(filename, &statbuf), result); | |
376 if (result == OS_ERR) { | |
377 FREE_C_HEAP_ARRAY(char, filename); | |
378 continue; | |
379 } | |
380 | |
381 // skip over files that are not regular files. | |
382 if (!S_ISREG(statbuf.st_mode)) { | |
383 FREE_C_HEAP_ARRAY(char, filename); | |
384 continue; | |
385 } | |
386 | |
387 // compare and save filename with latest creation time | |
388 if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) { | |
389 | |
390 if (statbuf.st_ctime > oldest_ctime) { | |
391 char* user = strchr(dentry->d_name, '_') + 1; | |
392 | |
393 if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user); | |
394 oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1); | |
395 | |
396 strcpy(oldest_user, user); | |
397 oldest_ctime = statbuf.st_ctime; | |
398 } | |
399 } | |
400 | |
401 FREE_C_HEAP_ARRAY(char, filename); | |
402 } | |
403 } | |
404 os::closedir(subdirp); | |
405 FREE_C_HEAP_ARRAY(char, udbuf); | |
406 FREE_C_HEAP_ARRAY(char, usrdir_name); | |
407 } | |
408 os::closedir(tmpdirp); | |
409 FREE_C_HEAP_ARRAY(char, tdbuf); | |
410 | |
411 return(oldest_user); | |
412 } | |
413 | |
414 // return the name of the user that owns the JVM indicated by the given vmid. | |
415 // | |
416 static char* get_user_name(int vmid, TRAPS) { | |
417 return get_user_name_slow(vmid, CHECK_NULL); | |
418 } | |
419 | |
420 // return the file name of the backing store file for the named | |
421 // shared memory region for the given user name and vmid. | |
422 // | |
423 // the caller is expected to free the allocated memory. | |
424 // | |
425 static char* get_sharedmem_filename(const char* dirname, int vmid) { | |
426 | |
427 // add 2 for the file separator and a null terminator. | |
428 size_t nbytes = strlen(dirname) + UINT_CHARS + 2; | |
429 | |
430 char* name = NEW_C_HEAP_ARRAY(char, nbytes); | |
431 snprintf(name, nbytes, "%s/%d", dirname, vmid); | |
432 | |
433 return name; | |
434 } | |
435 | |
436 | |
437 // remove file | |
438 // | |
439 // this method removes the file specified by the given path | |
440 // | |
441 static void remove_file(const char* path) { | |
442 | |
443 int result; | |
444 | |
445 // if the file is a directory, the following unlink will fail. since | |
446 // we don't expect to find directories in the user temp directory, we | |
447 // won't try to handle this situation. even if accidentially or | |
448 // maliciously planted, the directory's presence won't hurt anything. | |
449 // | |
450 RESTARTABLE(::unlink(path), result); | |
451 if (PrintMiscellaneous && Verbose && result == OS_ERR) { | |
452 if (errno != ENOENT) { | |
453 warning("Could not unlink shared memory backing" | |
454 " store file %s : %s\n", path, strerror(errno)); | |
455 } | |
456 } | |
457 } | |
458 | |
459 | |
460 // remove file | |
461 // | |
462 // this method removes the file with the given file name in the | |
463 // named directory. | |
464 // | |
465 static void remove_file(const char* dirname, const char* filename) { | |
466 | |
467 size_t nbytes = strlen(dirname) + strlen(filename) + 2; | |
468 char* path = NEW_C_HEAP_ARRAY(char, nbytes); | |
469 | |
470 strcpy(path, dirname); | |
471 strcat(path, "/"); | |
472 strcat(path, filename); | |
473 | |
474 remove_file(path); | |
475 | |
476 FREE_C_HEAP_ARRAY(char, path); | |
477 } | |
478 | |
479 | |
480 // cleanup stale shared memory resources | |
481 // | |
482 // This method attempts to remove all stale shared memory files in | |
483 // the named user temporary directory. It scans the named directory | |
484 // for files matching the pattern ^$[0-9]*$. For each file found, the | |
485 // process id is extracted from the file name and a test is run to | |
486 // determine if the process is alive. If the process is not alive, | |
487 // any stale file resources are removed. | |
488 // | |
489 static void cleanup_sharedmem_resources(const char* dirname) { | |
490 | |
491 // open the user temp directory | |
492 DIR* dirp = os::opendir(dirname); | |
493 | |
494 if (dirp == NULL) { | |
495 // directory doesn't exist, so there is nothing to cleanup | |
496 return; | |
497 } | |
498 | |
499 if (!is_directory_secure(dirname)) { | |
500 // the directory is not a secure directory | |
501 return; | |
502 } | |
503 | |
504 // for each entry in the directory that matches the expected file | |
505 // name pattern, determine if the file resources are stale and if | |
506 // so, remove the file resources. Note, instrumented HotSpot processes | |
507 // for this user may start and/or terminate during this search and | |
508 // remove or create new files in this directory. The behavior of this | |
509 // loop under these conditions is dependent upon the implementation of | |
510 // opendir/readdir. | |
511 // | |
512 struct dirent* entry; | |
513 char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname)); | |
514 errno = 0; | |
515 while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) { | |
516 | |
517 pid_t pid = filename_to_pid(entry->d_name); | |
518 | |
519 if (pid == 0) { | |
520 | |
521 if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) { | |
522 | |
523 // attempt to remove all unexpected files, except "." and ".." | |
524 remove_file(dirname, entry->d_name); | |
525 } | |
526 | |
527 errno = 0; | |
528 continue; | |
529 } | |
530 | |
531 // we now have a file name that converts to a valid integer | |
532 // that could represent a process id . if this process id | |
533 // matches the current process id or the process is not running, | |
534 // then remove the stale file resources. | |
535 // | |
536 // process liveness is detected by sending signal number 0 to | |
537 // the process id (see kill(2)). if kill determines that the | |
538 // process does not exist, then the file resources are removed. | |
539 // if kill determines that that we don't have permission to | |
540 // signal the process, then the file resources are assumed to | |
541 // be stale and are removed because the resources for such a | |
542 // process should be in a different user specific directory. | |
543 // | |
544 if ((pid == os::current_process_id()) || | |
545 (kill(pid, 0) == OS_ERR && (errno == ESRCH || errno == EPERM))) { | |
546 | |
547 remove_file(dirname, entry->d_name); | |
548 } | |
549 errno = 0; | |
550 } | |
551 os::closedir(dirp); | |
552 FREE_C_HEAP_ARRAY(char, dbuf); | |
553 } | |
554 | |
555 // make the user specific temporary directory. Returns true if | |
556 // the directory exists and is secure upon return. Returns false | |
557 // if the directory exists but is either a symlink, is otherwise | |
558 // insecure, or if an error occurred. | |
559 // | |
560 static bool make_user_tmp_dir(const char* dirname) { | |
561 | |
562 // create the directory with 0755 permissions. note that the directory | |
563 // will be owned by euid::egid, which may not be the same as uid::gid. | |
564 // | |
565 if (mkdir(dirname, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) == OS_ERR) { | |
566 if (errno == EEXIST) { | |
567 // The directory already exists and was probably created by another | |
568 // JVM instance. However, this could also be the result of a | |
569 // deliberate symlink. Verify that the existing directory is safe. | |
570 // | |
571 if (!is_directory_secure(dirname)) { | |
572 // directory is not secure | |
573 if (PrintMiscellaneous && Verbose) { | |
574 warning("%s directory is insecure\n", dirname); | |
575 } | |
576 return false; | |
577 } | |
578 } | |
579 else { | |
580 // we encountered some other failure while attempting | |
581 // to create the directory | |
582 // | |
583 if (PrintMiscellaneous && Verbose) { | |
584 warning("could not create directory %s: %s\n", | |
585 dirname, strerror(errno)); | |
586 } | |
587 return false; | |
588 } | |
589 } | |
590 return true; | |
591 } | |
592 | |
593 // create the shared memory file resources | |
594 // | |
595 // This method creates the shared memory file with the given size | |
596 // This method also creates the user specific temporary directory, if | |
597 // it does not yet exist. | |
598 // | |
599 static int create_sharedmem_resources(const char* dirname, const char* filename, size_t size) { | |
600 | |
601 // make the user temporary directory | |
602 if (!make_user_tmp_dir(dirname)) { | |
603 // could not make/find the directory or the found directory | |
604 // was not secure | |
605 return -1; | |
606 } | |
607 | |
608 int result; | |
609 | |
610 RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_TRUNC, S_IREAD|S_IWRITE), result); | |
611 if (result == OS_ERR) { | |
612 if (PrintMiscellaneous && Verbose) { | |
613 warning("could not create file %s: %s\n", filename, strerror(errno)); | |
614 } | |
615 return -1; | |
616 } | |
617 | |
618 // save the file descriptor | |
619 int fd = result; | |
620 | |
621 // set the file size | |
622 RESTARTABLE(::ftruncate(fd, (off_t)size), result); | |
623 if (result == OS_ERR) { | |
624 if (PrintMiscellaneous && Verbose) { | |
625 warning("could not set shared memory file size: %s\n", strerror(errno)); | |
626 } | |
627 RESTARTABLE(::close(fd), result); | |
628 return -1; | |
629 } | |
630 | |
631 return fd; | |
632 } | |
633 | |
634 // open the shared memory file for the given user and vmid. returns | |
635 // the file descriptor for the open file or -1 if the file could not | |
636 // be opened. | |
637 // | |
638 static int open_sharedmem_file(const char* filename, int oflags, TRAPS) { | |
639 | |
640 // open the file | |
641 int result; | |
642 RESTARTABLE(::open(filename, oflags), result); | |
643 if (result == OS_ERR) { | |
644 if (errno == ENOENT) { | |
645 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), | |
646 "Process not found"); | |
647 } | |
648 else if (errno == EACCES) { | |
649 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), | |
650 "Permission denied"); | |
651 } | |
652 else { | |
653 THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno)); | |
654 } | |
655 } | |
656 | |
657 return result; | |
658 } | |
659 | |
660 // create a named shared memory region. returns the address of the | |
661 // memory region on success or NULL on failure. A return value of | |
662 // NULL will ultimately disable the shared memory feature. | |
663 // | |
664 // On Solaris and Linux, the name space for shared memory objects | |
665 // is the file system name space. | |
666 // | |
667 // A monitoring application attaching to a JVM does not need to know | |
668 // the file system name of the shared memory object. However, it may | |
669 // be convenient for applications to discover the existence of newly | |
670 // created and terminating JVMs by watching the file system name space | |
671 // for files being created or removed. | |
672 // | |
673 static char* mmap_create_shared(size_t size) { | |
674 | |
675 int result; | |
676 int fd; | |
677 char* mapAddress; | |
678 | |
679 int vmid = os::current_process_id(); | |
680 | |
681 char* user_name = get_user_name(geteuid()); | |
682 | |
683 if (user_name == NULL) | |
684 return NULL; | |
685 | |
686 char* dirname = get_user_tmp_dir(user_name); | |
687 char* filename = get_sharedmem_filename(dirname, vmid); | |
688 | |
689 // cleanup any stale shared memory files | |
690 cleanup_sharedmem_resources(dirname); | |
691 | |
692 assert(((size > 0) && (size % os::vm_page_size() == 0)), | |
693 "unexpected PerfMemory region size"); | |
694 | |
695 fd = create_sharedmem_resources(dirname, filename, size); | |
696 | |
697 FREE_C_HEAP_ARRAY(char, user_name); | |
698 FREE_C_HEAP_ARRAY(char, dirname); | |
699 | |
700 if (fd == -1) { | |
701 FREE_C_HEAP_ARRAY(char, filename); | |
702 return NULL; | |
703 } | |
704 | |
705 mapAddress = (char*)::mmap((char*)0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); | |
706 | |
707 // attempt to close the file - restart it if it was interrupted, | |
708 // but ignore other failures | |
709 RESTARTABLE(::close(fd), result); | |
710 assert(result != OS_ERR, "could not close file"); | |
711 | |
712 if (mapAddress == MAP_FAILED) { | |
713 if (PrintMiscellaneous && Verbose) { | |
714 warning("mmap failed - %s\n", strerror(errno)); | |
715 } | |
716 remove_file(filename); | |
717 FREE_C_HEAP_ARRAY(char, filename); | |
718 return NULL; | |
719 } | |
720 | |
721 // save the file name for use in delete_shared_memory() | |
722 backing_store_file_name = filename; | |
723 | |
724 // clear the shared memory region | |
725 (void)::memset((void*) mapAddress, 0, size); | |
726 | |
727 return mapAddress; | |
728 } | |
729 | |
730 // release a named shared memory region | |
731 // | |
732 static void unmap_shared(char* addr, size_t bytes) { | |
733 os::release_memory(addr, bytes); | |
734 } | |
735 | |
736 // create the PerfData memory region in shared memory. | |
737 // | |
738 static char* create_shared_memory(size_t size) { | |
739 | |
740 // create the shared memory region. | |
741 return mmap_create_shared(size); | |
742 } | |
743 | |
744 // delete the shared PerfData memory region | |
745 // | |
746 static void delete_shared_memory(char* addr, size_t size) { | |
747 | |
748 // cleanup the persistent shared memory resources. since DestroyJavaVM does | |
749 // not support unloading of the JVM, unmapping of the memory resource is | |
750 // not performed. The memory will be reclaimed by the OS upon termination of | |
751 // the process. The backing store file is deleted from the file system. | |
752 | |
753 assert(!PerfDisableSharedMem, "shouldn't be here"); | |
754 | |
755 if (backing_store_file_name != NULL) { | |
756 remove_file(backing_store_file_name); | |
757 // Don't.. Free heap memory could deadlock os::abort() if it is called | |
758 // from signal handler. OS will reclaim the heap memory. | |
759 // FREE_C_HEAP_ARRAY(char, backing_store_file_name); | |
760 backing_store_file_name = NULL; | |
761 } | |
762 } | |
763 | |
764 // return the size of the file for the given file descriptor | |
765 // or 0 if it is not a valid size for a shared memory file | |
766 // | |
767 static size_t sharedmem_filesize(int fd, TRAPS) { | |
768 | |
769 struct stat statbuf; | |
770 int result; | |
771 | |
772 RESTARTABLE(::fstat(fd, &statbuf), result); | |
773 if (result == OS_ERR) { | |
774 if (PrintMiscellaneous && Verbose) { | |
775 warning("fstat failed: %s\n", strerror(errno)); | |
776 } | |
777 THROW_MSG_0(vmSymbols::java_io_IOException(), | |
778 "Could not determine PerfMemory size"); | |
779 } | |
780 | |
781 if ((statbuf.st_size == 0) || | |
782 ((size_t)statbuf.st_size % os::vm_page_size() != 0)) { | |
783 THROW_MSG_0(vmSymbols::java_lang_Exception(), | |
784 "Invalid PerfMemory size"); | |
785 } | |
786 | |
787 return (size_t)statbuf.st_size; | |
788 } | |
789 | |
790 // attach to a named shared memory region. | |
791 // | |
792 static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemoryMode mode, char** addr, size_t* sizep, TRAPS) { | |
793 | |
794 char* mapAddress; | |
795 int result; | |
796 int fd; | |
797 size_t size; | |
798 const char* luser = NULL; | |
799 | |
800 int mmap_prot; | |
801 int file_flags; | |
802 | |
803 ResourceMark rm; | |
804 | |
805 // map the high level access mode to the appropriate permission | |
806 // constructs for the file and the shared memory mapping. | |
807 if (mode == PerfMemory::PERF_MODE_RO) { | |
808 mmap_prot = PROT_READ; | |
809 file_flags = O_RDONLY; | |
810 } | |
811 else if (mode == PerfMemory::PERF_MODE_RW) { | |
812 #ifdef LATER | |
813 mmap_prot = PROT_READ | PROT_WRITE; | |
814 file_flags = O_RDWR; | |
815 #else | |
816 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
817 "Unsupported access mode"); | |
818 #endif | |
819 } | |
820 else { | |
821 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
822 "Illegal access mode"); | |
823 } | |
824 | |
825 if (user == NULL || strlen(user) == 0) { | |
826 luser = get_user_name(vmid, CHECK); | |
827 } | |
828 else { | |
829 luser = user; | |
830 } | |
831 | |
832 if (luser == NULL) { | |
833 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
834 "Could not map vmid to user Name"); | |
835 } | |
836 | |
837 char* dirname = get_user_tmp_dir(luser); | |
838 | |
839 // since we don't follow symbolic links when creating the backing | |
840 // store file, we don't follow them when attaching either. | |
841 // | |
842 if (!is_directory_secure(dirname)) { | |
843 FREE_C_HEAP_ARRAY(char, dirname); | |
844 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
845 "Process not found"); | |
846 } | |
847 | |
848 char* filename = get_sharedmem_filename(dirname, vmid); | |
849 | |
850 // copy heap memory to resource memory. the open_sharedmem_file | |
851 // method below need to use the filename, but could throw an | |
852 // exception. using a resource array prevents the leak that | |
853 // would otherwise occur. | |
854 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1); | |
855 strcpy(rfilename, filename); | |
856 | |
857 // free the c heap resources that are no longer needed | |
858 if (luser != user) FREE_C_HEAP_ARRAY(char, luser); | |
859 FREE_C_HEAP_ARRAY(char, dirname); | |
860 FREE_C_HEAP_ARRAY(char, filename); | |
861 | |
862 // open the shared memory file for the give vmid | |
863 fd = open_sharedmem_file(rfilename, file_flags, CHECK); | |
864 assert(fd != OS_ERR, "unexpected value"); | |
865 | |
866 if (*sizep == 0) { | |
867 size = sharedmem_filesize(fd, CHECK); | |
868 assert(size != 0, "unexpected size"); | |
869 } | |
870 | |
871 mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0); | |
872 | |
873 // attempt to close the file - restart if it gets interrupted, | |
874 // but ignore other failures | |
875 RESTARTABLE(::close(fd), result); | |
876 assert(result != OS_ERR, "could not close file"); | |
877 | |
878 if (mapAddress == MAP_FAILED) { | |
879 if (PrintMiscellaneous && Verbose) { | |
880 warning("mmap failed: %s\n", strerror(errno)); | |
881 } | |
882 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(), | |
883 "Could not map PerfMemory"); | |
884 } | |
885 | |
886 *addr = mapAddress; | |
887 *sizep = size; | |
888 | |
889 if (PerfTraceMemOps) { | |
890 tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at " | |
891 INTPTR_FORMAT "\n", size, vmid, (void*)mapAddress); | |
892 } | |
893 } | |
894 | |
895 | |
896 | |
897 | |
898 // create the PerfData memory region | |
899 // | |
900 // This method creates the memory region used to store performance | |
901 // data for the JVM. The memory may be created in standard or | |
902 // shared memory. | |
903 // | |
904 void PerfMemory::create_memory_region(size_t size) { | |
905 | |
906 if (PerfDisableSharedMem) { | |
907 // do not share the memory for the performance data. | |
908 _start = create_standard_memory(size); | |
909 } | |
910 else { | |
911 _start = create_shared_memory(size); | |
912 if (_start == NULL) { | |
913 | |
914 // creation of the shared memory region failed, attempt | |
915 // to create a contiguous, non-shared memory region instead. | |
916 // | |
917 if (PrintMiscellaneous && Verbose) { | |
918 warning("Reverting to non-shared PerfMemory region.\n"); | |
919 } | |
920 PerfDisableSharedMem = true; | |
921 _start = create_standard_memory(size); | |
922 } | |
923 } | |
924 | |
925 if (_start != NULL) _capacity = size; | |
926 | |
927 } | |
928 | |
929 // delete the PerfData memory region | |
930 // | |
931 // This method deletes the memory region used to store performance | |
932 // data for the JVM. The memory region indicated by the <address, size> | |
933 // tuple will be inaccessible after a call to this method. | |
934 // | |
935 void PerfMemory::delete_memory_region() { | |
936 | |
937 assert((start() != NULL && capacity() > 0), "verify proper state"); | |
938 | |
939 // If user specifies PerfDataSaveFile, it will save the performance data | |
940 // to the specified file name no matter whether PerfDataSaveToFile is specified | |
941 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag | |
942 // -XX:+PerfDataSaveToFile. | |
943 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) { | |
944 save_memory_to_file(start(), capacity()); | |
945 } | |
946 | |
947 if (PerfDisableSharedMem) { | |
948 delete_standard_memory(start(), capacity()); | |
949 } | |
950 else { | |
951 delete_shared_memory(start(), capacity()); | |
952 } | |
953 } | |
954 | |
955 // attach to the PerfData memory region for another JVM | |
956 // | |
957 // This method returns an <address, size> tuple that points to | |
958 // a memory buffer that is kept reasonably synchronized with | |
959 // the PerfData memory region for the indicated JVM. This | |
960 // buffer may be kept in synchronization via shared memory | |
961 // or some other mechanism that keeps the buffer updated. | |
962 // | |
963 // If the JVM chooses not to support the attachability feature, | |
964 // this method should throw an UnsupportedOperation exception. | |
965 // | |
966 // This implementation utilizes named shared memory to map | |
967 // the indicated process's PerfData memory region into this JVMs | |
968 // address space. | |
969 // | |
970 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, char** addrp, size_t* sizep, TRAPS) { | |
971 | |
972 if (vmid == 0 || vmid == os::current_process_id()) { | |
973 *addrp = start(); | |
974 *sizep = capacity(); | |
975 return; | |
976 } | |
977 | |
978 mmap_attach_shared(user, vmid, mode, addrp, sizep, CHECK); | |
979 } | |
980 | |
981 // detach from the PerfData memory region of another JVM | |
982 // | |
983 // This method detaches the PerfData memory region of another | |
984 // JVM, specified as an <address, size> tuple of a buffer | |
985 // in this process's address space. This method may perform | |
986 // arbitrary actions to accomplish the detachment. The memory | |
987 // region specified by <address, size> will be inaccessible after | |
988 // a call to this method. | |
989 // | |
990 // If the JVM chooses not to support the attachability feature, | |
991 // this method should throw an UnsupportedOperation exception. | |
992 // | |
993 // This implementation utilizes named shared memory to detach | |
994 // the indicated process's PerfData memory region from this | |
995 // process's address space. | |
996 // | |
997 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) { | |
998 | |
999 assert(addr != 0, "address sanity check"); | |
1000 assert(bytes > 0, "capacity sanity check"); | |
1001 | |
1002 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) { | |
1003 // prevent accidental detachment of this process's PerfMemory region | |
1004 return; | |
1005 } | |
1006 | |
1007 unmap_shared(addr, bytes); | |
1008 } | |
1009 | |
1010 char* PerfMemory::backing_store_filename() { | |
1011 return backing_store_file_name; | |
1012 } |