Mercurial > hg > truffle
annotate src/os/linux/vm/perfMemory_linux.cpp @ 4617:113d66f7454d
Add merge-before-loopend simplification for merges
author | Gilles Duboscq <duboscq@ssw.jku.at> |
---|---|
date | Thu, 16 Feb 2012 14:43:05 +0100 |
parents | 02895c6a2f82 |
children | d2a62e0f25eb |
rev | line source |
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0 | 1 /* |
1972 | 2 * Copyright (c) 2001, 2010, 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 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "classfile/vmSymbols.hpp" | |
27 #include "memory/allocation.inline.hpp" | |
28 #include "memory/resourceArea.hpp" | |
29 #include "oops/oop.inline.hpp" | |
30 #include "os_linux.inline.hpp" | |
31 #include "runtime/handles.inline.hpp" | |
32 #include "runtime/perfMemory.hpp" | |
33 #include "utilities/exceptions.hpp" | |
0 | 34 |
35 // put OS-includes here | |
36 # include <sys/types.h> | |
37 # include <sys/mman.h> | |
38 # include <errno.h> | |
39 # include <stdio.h> | |
40 # include <unistd.h> | |
41 # include <sys/stat.h> | |
42 # include <signal.h> | |
43 # include <pwd.h> | |
44 | |
45 static char* backing_store_file_name = NULL; // name of the backing store | |
46 // file, if successfully created. | |
47 | |
48 // Standard Memory Implementation Details | |
49 | |
50 // create the PerfData memory region in standard memory. | |
51 // | |
52 static char* create_standard_memory(size_t size) { | |
53 | |
54 // allocate an aligned chuck of memory | |
55 char* mapAddress = os::reserve_memory(size); | |
56 | |
57 if (mapAddress == NULL) { | |
58 return NULL; | |
59 } | |
60 | |
61 // commit memory | |
62 if (!os::commit_memory(mapAddress, size)) { | |
63 if (PrintMiscellaneous && Verbose) { | |
64 warning("Could not commit PerfData memory\n"); | |
65 } | |
66 os::release_memory(mapAddress, size); | |
67 return NULL; | |
68 } | |
69 | |
70 return mapAddress; | |
71 } | |
72 | |
73 // delete the PerfData memory region | |
74 // | |
75 static void delete_standard_memory(char* addr, size_t size) { | |
76 | |
77 // there are no persistent external resources to cleanup for standard | |
78 // memory. since DestroyJavaVM does not support unloading of the JVM, | |
79 // cleanup of the memory resource is not performed. The memory will be | |
80 // reclaimed by the OS upon termination of the process. | |
81 // | |
82 return; | |
83 } | |
84 | |
85 // save the specified memory region to the given file | |
86 // | |
87 // Note: this function might be called from signal handler (by os::abort()), | |
88 // don't allocate heap memory. | |
89 // | |
90 static void save_memory_to_file(char* addr, size_t size) { | |
91 | |
92 const char* destfile = PerfMemory::get_perfdata_file_path(); | |
93 assert(destfile[0] != '\0', "invalid PerfData file path"); | |
94 | |
95 int result; | |
96 | |
97 RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE), | |
98 result);; | |
99 if (result == OS_ERR) { | |
100 if (PrintMiscellaneous && Verbose) { | |
101 warning("Could not create Perfdata save file: %s: %s\n", | |
102 destfile, strerror(errno)); | |
103 } | |
104 } else { | |
105 int fd = result; | |
106 | |
107 for (size_t remaining = size; remaining > 0;) { | |
108 | |
109 RESTARTABLE(::write(fd, addr, remaining), result); | |
110 if (result == OS_ERR) { | |
111 if (PrintMiscellaneous && Verbose) { | |
112 warning("Could not write Perfdata save file: %s: %s\n", | |
113 destfile, strerror(errno)); | |
114 } | |
115 break; | |
116 } | |
117 | |
118 remaining -= (size_t)result; | |
119 addr += result; | |
120 } | |
121 | |
122 RESTARTABLE(::close(fd), result); | |
123 if (PrintMiscellaneous && Verbose) { | |
124 if (result == OS_ERR) { | |
125 warning("Could not close %s: %s\n", destfile, strerror(errno)); | |
126 } | |
127 } | |
128 } | |
129 FREE_C_HEAP_ARRAY(char, destfile); | |
130 } | |
131 | |
132 | |
133 // Shared Memory Implementation Details | |
134 | |
135 // Note: the solaris and linux shared memory implementation uses the mmap | |
136 // interface with a backing store file to implement named shared memory. | |
137 // Using the file system as the name space for shared memory allows a | |
138 // common name space to be supported across a variety of platforms. It | |
139 // also provides a name space that Java applications can deal with through | |
140 // simple file apis. | |
141 // | |
142 // The solaris and linux implementations store the backing store file in | |
143 // a user specific temporary directory located in the /tmp file system, | |
144 // which is always a local file system and is sometimes a RAM based file | |
145 // system. | |
146 | |
147 // return the user specific temporary directory name. | |
148 // | |
149 // the caller is expected to free the allocated memory. | |
150 // | |
151 static char* get_user_tmp_dir(const char* user) { | |
152 | |
153 const char* tmpdir = os::get_temp_directory(); | |
154 const char* perfdir = PERFDATA_NAME; | |
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155 size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3; |
0 | 156 char* dirname = NEW_C_HEAP_ARRAY(char, nbytes); |
157 | |
158 // construct the path name to user specific tmp directory | |
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159 snprintf(dirname, nbytes, "%s/%s_%s", tmpdir, perfdir, user); |
0 | 160 |
161 return dirname; | |
162 } | |
163 | |
164 // convert the given file name into a process id. if the file | |
165 // does not meet the file naming constraints, return 0. | |
166 // | |
167 static pid_t filename_to_pid(const char* filename) { | |
168 | |
169 // a filename that doesn't begin with a digit is not a | |
170 // candidate for conversion. | |
171 // | |
172 if (!isdigit(*filename)) { | |
173 return 0; | |
174 } | |
175 | |
176 // check if file name can be converted to an integer without | |
177 // any leftover characters. | |
178 // | |
179 char* remainder = NULL; | |
180 errno = 0; | |
181 pid_t pid = (pid_t)strtol(filename, &remainder, 10); | |
182 | |
183 if (errno != 0) { | |
184 return 0; | |
185 } | |
186 | |
187 // check for left over characters. If any, then the filename is | |
188 // not a candidate for conversion. | |
189 // | |
190 if (remainder != NULL && *remainder != '\0') { | |
191 return 0; | |
192 } | |
193 | |
194 // successful conversion, return the pid | |
195 return pid; | |
196 } | |
197 | |
198 | |
199 // check if the given path is considered a secure directory for | |
200 // the backing store files. Returns true if the directory exists | |
201 // and is considered a secure location. Returns false if the path | |
605 | 202 // is a symbolic link or if an error occurred. |
0 | 203 // |
204 static bool is_directory_secure(const char* path) { | |
205 struct stat statbuf; | |
206 int result = 0; | |
207 | |
208 RESTARTABLE(::lstat(path, &statbuf), result); | |
209 if (result == OS_ERR) { | |
210 return false; | |
211 } | |
212 | |
213 // the path exists, now check it's mode | |
214 if (S_ISLNK(statbuf.st_mode) || !S_ISDIR(statbuf.st_mode)) { | |
215 // the path represents a link or some non-directory file type, | |
216 // which is not what we expected. declare it insecure. | |
217 // | |
218 return false; | |
219 } | |
220 else { | |
221 // we have an existing directory, check if the permissions are safe. | |
222 // | |
223 if ((statbuf.st_mode & (S_IWGRP|S_IWOTH)) != 0) { | |
224 // the directory is open for writing and could be subjected | |
225 // to a symlnk attack. declare it insecure. | |
226 // | |
227 return false; | |
228 } | |
229 } | |
230 return true; | |
231 } | |
232 | |
233 | |
234 // return the user name for the given user id | |
235 // | |
236 // the caller is expected to free the allocated memory. | |
237 // | |
238 static char* get_user_name(uid_t uid) { | |
239 | |
240 struct passwd pwent; | |
241 | |
242 // determine the max pwbuf size from sysconf, and hardcode | |
243 // a default if this not available through sysconf. | |
244 // | |
245 long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX); | |
246 if (bufsize == -1) | |
247 bufsize = 1024; | |
248 | |
249 char* pwbuf = NEW_C_HEAP_ARRAY(char, bufsize); | |
250 | |
251 // POSIX interface to getpwuid_r is used on LINUX | |
252 struct passwd* p; | |
253 int result = getpwuid_r(uid, &pwent, pwbuf, (size_t)bufsize, &p); | |
254 | |
255 if (result != 0 || p == NULL || p->pw_name == NULL || *(p->pw_name) == '\0') { | |
256 if (PrintMiscellaneous && Verbose) { | |
257 if (result != 0) { | |
258 warning("Could not retrieve passwd entry: %s\n", | |
259 strerror(result)); | |
260 } | |
261 else if (p == NULL) { | |
262 // this check is added to protect against an observed problem | |
263 // with getpwuid_r() on RedHat 9 where getpwuid_r returns 0, | |
264 // indicating success, but has p == NULL. This was observed when | |
265 // inserting a file descriptor exhaustion fault prior to the call | |
266 // getpwuid_r() call. In this case, error is set to the appropriate | |
267 // error condition, but this is undocumented behavior. This check | |
268 // is safe under any condition, but the use of errno in the output | |
269 // message may result in an erroneous message. | |
270 // Bug Id 89052 was opened with RedHat. | |
271 // | |
272 warning("Could not retrieve passwd entry: %s\n", | |
273 strerror(errno)); | |
274 } | |
275 else { | |
276 warning("Could not determine user name: %s\n", | |
277 p->pw_name == NULL ? "pw_name = NULL" : | |
278 "pw_name zero length"); | |
279 } | |
280 } | |
281 FREE_C_HEAP_ARRAY(char, pwbuf); | |
282 return NULL; | |
283 } | |
284 | |
285 char* user_name = NEW_C_HEAP_ARRAY(char, strlen(p->pw_name) + 1); | |
286 strcpy(user_name, p->pw_name); | |
287 | |
288 FREE_C_HEAP_ARRAY(char, pwbuf); | |
289 return user_name; | |
290 } | |
291 | |
292 // return the name of the user that owns the process identified by vmid. | |
293 // | |
294 // This method uses a slow directory search algorithm to find the backing | |
295 // store file for the specified vmid and returns the user name, as determined | |
296 // by the user name suffix of the hsperfdata_<username> directory name. | |
297 // | |
298 // the caller is expected to free the allocated memory. | |
299 // | |
300 static char* get_user_name_slow(int vmid, TRAPS) { | |
301 | |
302 // short circuit the directory search if the process doesn't even exist. | |
303 if (kill(vmid, 0) == OS_ERR) { | |
304 if (errno == ESRCH) { | |
305 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), | |
306 "Process not found"); | |
307 } | |
308 else /* EPERM */ { | |
309 THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno)); | |
310 } | |
311 } | |
312 | |
313 // directory search | |
314 char* oldest_user = NULL; | |
315 time_t oldest_ctime = 0; | |
316 | |
317 const char* tmpdirname = os::get_temp_directory(); | |
318 | |
319 DIR* tmpdirp = os::opendir(tmpdirname); | |
320 | |
321 if (tmpdirp == NULL) { | |
322 return NULL; | |
323 } | |
324 | |
325 // for each entry in the directory that matches the pattern hsperfdata_*, | |
326 // open the directory and check if the file for the given vmid exists. | |
327 // The file with the expected name and the latest creation date is used | |
328 // to determine the user name for the process id. | |
329 // | |
330 struct dirent* dentry; | |
331 char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname)); | |
332 errno = 0; | |
333 while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) { | |
334 | |
335 // check if the directory entry is a hsperfdata file | |
336 if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) { | |
337 continue; | |
338 } | |
339 | |
340 char* usrdir_name = NEW_C_HEAP_ARRAY(char, | |
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341 strlen(tmpdirname) + strlen(dentry->d_name) + 2); |
0 | 342 strcpy(usrdir_name, tmpdirname); |
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343 strcat(usrdir_name, "/"); |
0 | 344 strcat(usrdir_name, dentry->d_name); |
345 | |
346 DIR* subdirp = os::opendir(usrdir_name); | |
347 | |
348 if (subdirp == NULL) { | |
349 FREE_C_HEAP_ARRAY(char, usrdir_name); | |
350 continue; | |
351 } | |
352 | |
353 // Since we don't create the backing store files in directories | |
354 // pointed to by symbolic links, we also don't follow them when | |
355 // looking for the files. We check for a symbolic link after the | |
356 // call to opendir in order to eliminate a small window where the | |
357 // symlink can be exploited. | |
358 // | |
359 if (!is_directory_secure(usrdir_name)) { | |
360 FREE_C_HEAP_ARRAY(char, usrdir_name); | |
361 os::closedir(subdirp); | |
362 continue; | |
363 } | |
364 | |
365 struct dirent* udentry; | |
366 char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name)); | |
367 errno = 0; | |
368 while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) { | |
369 | |
370 if (filename_to_pid(udentry->d_name) == vmid) { | |
371 struct stat statbuf; | |
372 int result; | |
373 | |
374 char* filename = NEW_C_HEAP_ARRAY(char, | |
375 strlen(usrdir_name) + strlen(udentry->d_name) + 2); | |
376 | |
377 strcpy(filename, usrdir_name); | |
378 strcat(filename, "/"); | |
379 strcat(filename, udentry->d_name); | |
380 | |
381 // don't follow symbolic links for the file | |
382 RESTARTABLE(::lstat(filename, &statbuf), result); | |
383 if (result == OS_ERR) { | |
384 FREE_C_HEAP_ARRAY(char, filename); | |
385 continue; | |
386 } | |
387 | |
388 // skip over files that are not regular files. | |
389 if (!S_ISREG(statbuf.st_mode)) { | |
390 FREE_C_HEAP_ARRAY(char, filename); | |
391 continue; | |
392 } | |
393 | |
394 // compare and save filename with latest creation time | |
395 if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) { | |
396 | |
397 if (statbuf.st_ctime > oldest_ctime) { | |
398 char* user = strchr(dentry->d_name, '_') + 1; | |
399 | |
400 if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user); | |
401 oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1); | |
402 | |
403 strcpy(oldest_user, user); | |
404 oldest_ctime = statbuf.st_ctime; | |
405 } | |
406 } | |
407 | |
408 FREE_C_HEAP_ARRAY(char, filename); | |
409 } | |
410 } | |
411 os::closedir(subdirp); | |
412 FREE_C_HEAP_ARRAY(char, udbuf); | |
413 FREE_C_HEAP_ARRAY(char, usrdir_name); | |
414 } | |
415 os::closedir(tmpdirp); | |
416 FREE_C_HEAP_ARRAY(char, tdbuf); | |
417 | |
418 return(oldest_user); | |
419 } | |
420 | |
421 // return the name of the user that owns the JVM indicated by the given vmid. | |
422 // | |
423 static char* get_user_name(int vmid, TRAPS) { | |
424 return get_user_name_slow(vmid, CHECK_NULL); | |
425 } | |
426 | |
427 // return the file name of the backing store file for the named | |
428 // shared memory region for the given user name and vmid. | |
429 // | |
430 // the caller is expected to free the allocated memory. | |
431 // | |
432 static char* get_sharedmem_filename(const char* dirname, int vmid) { | |
433 | |
434 // add 2 for the file separator and a null terminator. | |
435 size_t nbytes = strlen(dirname) + UINT_CHARS + 2; | |
436 | |
437 char* name = NEW_C_HEAP_ARRAY(char, nbytes); | |
438 snprintf(name, nbytes, "%s/%d", dirname, vmid); | |
439 | |
440 return name; | |
441 } | |
442 | |
443 | |
444 // remove file | |
445 // | |
446 // this method removes the file specified by the given path | |
447 // | |
448 static void remove_file(const char* path) { | |
449 | |
450 int result; | |
451 | |
452 // if the file is a directory, the following unlink will fail. since | |
453 // we don't expect to find directories in the user temp directory, we | |
454 // won't try to handle this situation. even if accidentially or | |
455 // maliciously planted, the directory's presence won't hurt anything. | |
456 // | |
457 RESTARTABLE(::unlink(path), result); | |
458 if (PrintMiscellaneous && Verbose && result == OS_ERR) { | |
459 if (errno != ENOENT) { | |
460 warning("Could not unlink shared memory backing" | |
461 " store file %s : %s\n", path, strerror(errno)); | |
462 } | |
463 } | |
464 } | |
465 | |
466 | |
467 // remove file | |
468 // | |
469 // this method removes the file with the given file name in the | |
470 // named directory. | |
471 // | |
472 static void remove_file(const char* dirname, const char* filename) { | |
473 | |
474 size_t nbytes = strlen(dirname) + strlen(filename) + 2; | |
475 char* path = NEW_C_HEAP_ARRAY(char, nbytes); | |
476 | |
477 strcpy(path, dirname); | |
478 strcat(path, "/"); | |
479 strcat(path, filename); | |
480 | |
481 remove_file(path); | |
482 | |
483 FREE_C_HEAP_ARRAY(char, path); | |
484 } | |
485 | |
486 | |
487 // cleanup stale shared memory resources | |
488 // | |
489 // This method attempts to remove all stale shared memory files in | |
490 // the named user temporary directory. It scans the named directory | |
491 // for files matching the pattern ^$[0-9]*$. For each file found, the | |
492 // process id is extracted from the file name and a test is run to | |
493 // determine if the process is alive. If the process is not alive, | |
494 // any stale file resources are removed. | |
495 // | |
496 static void cleanup_sharedmem_resources(const char* dirname) { | |
497 | |
498 // open the user temp directory | |
499 DIR* dirp = os::opendir(dirname); | |
500 | |
501 if (dirp == NULL) { | |
502 // directory doesn't exist, so there is nothing to cleanup | |
503 return; | |
504 } | |
505 | |
506 if (!is_directory_secure(dirname)) { | |
507 // the directory is not a secure directory | |
508 return; | |
509 } | |
510 | |
511 // for each entry in the directory that matches the expected file | |
512 // name pattern, determine if the file resources are stale and if | |
513 // so, remove the file resources. Note, instrumented HotSpot processes | |
514 // for this user may start and/or terminate during this search and | |
515 // remove or create new files in this directory. The behavior of this | |
516 // loop under these conditions is dependent upon the implementation of | |
517 // opendir/readdir. | |
518 // | |
519 struct dirent* entry; | |
520 char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname)); | |
521 errno = 0; | |
522 while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) { | |
523 | |
524 pid_t pid = filename_to_pid(entry->d_name); | |
525 | |
526 if (pid == 0) { | |
527 | |
528 if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) { | |
529 | |
530 // attempt to remove all unexpected files, except "." and ".." | |
531 remove_file(dirname, entry->d_name); | |
532 } | |
533 | |
534 errno = 0; | |
535 continue; | |
536 } | |
537 | |
538 // we now have a file name that converts to a valid integer | |
539 // that could represent a process id . if this process id | |
540 // matches the current process id or the process is not running, | |
541 // then remove the stale file resources. | |
542 // | |
543 // process liveness is detected by sending signal number 0 to | |
544 // the process id (see kill(2)). if kill determines that the | |
545 // process does not exist, then the file resources are removed. | |
546 // if kill determines that that we don't have permission to | |
547 // signal the process, then the file resources are assumed to | |
548 // be stale and are removed because the resources for such a | |
549 // process should be in a different user specific directory. | |
550 // | |
551 if ((pid == os::current_process_id()) || | |
552 (kill(pid, 0) == OS_ERR && (errno == ESRCH || errno == EPERM))) { | |
553 | |
554 remove_file(dirname, entry->d_name); | |
555 } | |
556 errno = 0; | |
557 } | |
558 os::closedir(dirp); | |
559 FREE_C_HEAP_ARRAY(char, dbuf); | |
560 } | |
561 | |
562 // make the user specific temporary directory. Returns true if | |
563 // the directory exists and is secure upon return. Returns false | |
564 // if the directory exists but is either a symlink, is otherwise | |
565 // insecure, or if an error occurred. | |
566 // | |
567 static bool make_user_tmp_dir(const char* dirname) { | |
568 | |
569 // create the directory with 0755 permissions. note that the directory | |
570 // will be owned by euid::egid, which may not be the same as uid::gid. | |
571 // | |
572 if (mkdir(dirname, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) == OS_ERR) { | |
573 if (errno == EEXIST) { | |
574 // The directory already exists and was probably created by another | |
575 // JVM instance. However, this could also be the result of a | |
576 // deliberate symlink. Verify that the existing directory is safe. | |
577 // | |
578 if (!is_directory_secure(dirname)) { | |
579 // directory is not secure | |
580 if (PrintMiscellaneous && Verbose) { | |
581 warning("%s directory is insecure\n", dirname); | |
582 } | |
583 return false; | |
584 } | |
585 } | |
586 else { | |
587 // we encountered some other failure while attempting | |
588 // to create the directory | |
589 // | |
590 if (PrintMiscellaneous && Verbose) { | |
591 warning("could not create directory %s: %s\n", | |
592 dirname, strerror(errno)); | |
593 } | |
594 return false; | |
595 } | |
596 } | |
597 return true; | |
598 } | |
599 | |
600 // create the shared memory file resources | |
601 // | |
602 // This method creates the shared memory file with the given size | |
603 // This method also creates the user specific temporary directory, if | |
604 // it does not yet exist. | |
605 // | |
606 static int create_sharedmem_resources(const char* dirname, const char* filename, size_t size) { | |
607 | |
608 // make the user temporary directory | |
609 if (!make_user_tmp_dir(dirname)) { | |
610 // could not make/find the directory or the found directory | |
611 // was not secure | |
612 return -1; | |
613 } | |
614 | |
615 int result; | |
616 | |
617 RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_TRUNC, S_IREAD|S_IWRITE), result); | |
618 if (result == OS_ERR) { | |
619 if (PrintMiscellaneous && Verbose) { | |
620 warning("could not create file %s: %s\n", filename, strerror(errno)); | |
621 } | |
622 return -1; | |
623 } | |
624 | |
625 // save the file descriptor | |
626 int fd = result; | |
627 | |
628 // set the file size | |
629 RESTARTABLE(::ftruncate(fd, (off_t)size), result); | |
630 if (result == OS_ERR) { | |
631 if (PrintMiscellaneous && Verbose) { | |
632 warning("could not set shared memory file size: %s\n", strerror(errno)); | |
633 } | |
634 RESTARTABLE(::close(fd), result); | |
635 return -1; | |
636 } | |
637 | |
2066
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638 // Verify that we have enough disk space for this file. |
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639 // We'll get random SIGBUS crashes on memory accesses if |
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640 // we don't. |
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641 |
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642 for (size_t seekpos = 0; seekpos < size; seekpos += os::vm_page_size()) { |
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643 int zero_int = 0; |
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644 result = (int)os::seek_to_file_offset(fd, (jlong)(seekpos)); |
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645 if (result == -1 ) break; |
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646 RESTARTABLE(::write(fd, &zero_int, 1), result); |
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647 if (result != 1) { |
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648 if (errno == ENOSPC) { |
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649 warning("Insufficient space for shared memory file:\n %s\nTry using the -Djava.io.tmpdir= option to select an alternate temp location.\n", filename); |
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650 } |
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651 break; |
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652 } |
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653 } |
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654 |
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655 if (result != -1) { |
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656 return fd; |
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657 } else { |
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658 RESTARTABLE(::close(fd), result); |
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659 return -1; |
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660 } |
0 | 661 } |
662 | |
663 // open the shared memory file for the given user and vmid. returns | |
664 // the file descriptor for the open file or -1 if the file could not | |
665 // be opened. | |
666 // | |
667 static int open_sharedmem_file(const char* filename, int oflags, TRAPS) { | |
668 | |
669 // open the file | |
670 int result; | |
671 RESTARTABLE(::open(filename, oflags), result); | |
672 if (result == OS_ERR) { | |
673 if (errno == ENOENT) { | |
674 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), | |
675 "Process not found"); | |
676 } | |
677 else if (errno == EACCES) { | |
678 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), | |
679 "Permission denied"); | |
680 } | |
681 else { | |
682 THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno)); | |
683 } | |
684 } | |
685 | |
686 return result; | |
687 } | |
688 | |
689 // create a named shared memory region. returns the address of the | |
690 // memory region on success or NULL on failure. A return value of | |
691 // NULL will ultimately disable the shared memory feature. | |
692 // | |
693 // On Solaris and Linux, the name space for shared memory objects | |
694 // is the file system name space. | |
695 // | |
696 // A monitoring application attaching to a JVM does not need to know | |
697 // the file system name of the shared memory object. However, it may | |
698 // be convenient for applications to discover the existence of newly | |
699 // created and terminating JVMs by watching the file system name space | |
700 // for files being created or removed. | |
701 // | |
702 static char* mmap_create_shared(size_t size) { | |
703 | |
704 int result; | |
705 int fd; | |
706 char* mapAddress; | |
707 | |
708 int vmid = os::current_process_id(); | |
709 | |
710 char* user_name = get_user_name(geteuid()); | |
711 | |
712 if (user_name == NULL) | |
713 return NULL; | |
714 | |
715 char* dirname = get_user_tmp_dir(user_name); | |
716 char* filename = get_sharedmem_filename(dirname, vmid); | |
717 | |
718 // cleanup any stale shared memory files | |
719 cleanup_sharedmem_resources(dirname); | |
720 | |
721 assert(((size > 0) && (size % os::vm_page_size() == 0)), | |
722 "unexpected PerfMemory region size"); | |
723 | |
724 fd = create_sharedmem_resources(dirname, filename, size); | |
725 | |
726 FREE_C_HEAP_ARRAY(char, user_name); | |
727 FREE_C_HEAP_ARRAY(char, dirname); | |
728 | |
729 if (fd == -1) { | |
730 FREE_C_HEAP_ARRAY(char, filename); | |
731 return NULL; | |
732 } | |
733 | |
734 mapAddress = (char*)::mmap((char*)0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); | |
735 | |
736 // attempt to close the file - restart it if it was interrupted, | |
737 // but ignore other failures | |
738 RESTARTABLE(::close(fd), result); | |
739 assert(result != OS_ERR, "could not close file"); | |
740 | |
741 if (mapAddress == MAP_FAILED) { | |
742 if (PrintMiscellaneous && Verbose) { | |
743 warning("mmap failed - %s\n", strerror(errno)); | |
744 } | |
745 remove_file(filename); | |
746 FREE_C_HEAP_ARRAY(char, filename); | |
747 return NULL; | |
748 } | |
749 | |
750 // save the file name for use in delete_shared_memory() | |
751 backing_store_file_name = filename; | |
752 | |
753 // clear the shared memory region | |
754 (void)::memset((void*) mapAddress, 0, size); | |
755 | |
756 return mapAddress; | |
757 } | |
758 | |
759 // release a named shared memory region | |
760 // | |
761 static void unmap_shared(char* addr, size_t bytes) { | |
762 os::release_memory(addr, bytes); | |
763 } | |
764 | |
765 // create the PerfData memory region in shared memory. | |
766 // | |
767 static char* create_shared_memory(size_t size) { | |
768 | |
769 // create the shared memory region. | |
770 return mmap_create_shared(size); | |
771 } | |
772 | |
773 // delete the shared PerfData memory region | |
774 // | |
775 static void delete_shared_memory(char* addr, size_t size) { | |
776 | |
777 // cleanup the persistent shared memory resources. since DestroyJavaVM does | |
778 // not support unloading of the JVM, unmapping of the memory resource is | |
779 // not performed. The memory will be reclaimed by the OS upon termination of | |
780 // the process. The backing store file is deleted from the file system. | |
781 | |
782 assert(!PerfDisableSharedMem, "shouldn't be here"); | |
783 | |
784 if (backing_store_file_name != NULL) { | |
785 remove_file(backing_store_file_name); | |
786 // Don't.. Free heap memory could deadlock os::abort() if it is called | |
787 // from signal handler. OS will reclaim the heap memory. | |
788 // FREE_C_HEAP_ARRAY(char, backing_store_file_name); | |
789 backing_store_file_name = NULL; | |
790 } | |
791 } | |
792 | |
793 // return the size of the file for the given file descriptor | |
794 // or 0 if it is not a valid size for a shared memory file | |
795 // | |
796 static size_t sharedmem_filesize(int fd, TRAPS) { | |
797 | |
798 struct stat statbuf; | |
799 int result; | |
800 | |
801 RESTARTABLE(::fstat(fd, &statbuf), result); | |
802 if (result == OS_ERR) { | |
803 if (PrintMiscellaneous && Verbose) { | |
804 warning("fstat failed: %s\n", strerror(errno)); | |
805 } | |
806 THROW_MSG_0(vmSymbols::java_io_IOException(), | |
807 "Could not determine PerfMemory size"); | |
808 } | |
809 | |
810 if ((statbuf.st_size == 0) || | |
811 ((size_t)statbuf.st_size % os::vm_page_size() != 0)) { | |
812 THROW_MSG_0(vmSymbols::java_lang_Exception(), | |
813 "Invalid PerfMemory size"); | |
814 } | |
815 | |
816 return (size_t)statbuf.st_size; | |
817 } | |
818 | |
819 // attach to a named shared memory region. | |
820 // | |
821 static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemoryMode mode, char** addr, size_t* sizep, TRAPS) { | |
822 | |
823 char* mapAddress; | |
824 int result; | |
825 int fd; | |
826 size_t size; | |
827 const char* luser = NULL; | |
828 | |
829 int mmap_prot; | |
830 int file_flags; | |
831 | |
832 ResourceMark rm; | |
833 | |
834 // map the high level access mode to the appropriate permission | |
835 // constructs for the file and the shared memory mapping. | |
836 if (mode == PerfMemory::PERF_MODE_RO) { | |
837 mmap_prot = PROT_READ; | |
838 file_flags = O_RDONLY; | |
839 } | |
840 else if (mode == PerfMemory::PERF_MODE_RW) { | |
841 #ifdef LATER | |
842 mmap_prot = PROT_READ | PROT_WRITE; | |
843 file_flags = O_RDWR; | |
844 #else | |
845 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
846 "Unsupported access mode"); | |
847 #endif | |
848 } | |
849 else { | |
850 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
851 "Illegal access mode"); | |
852 } | |
853 | |
854 if (user == NULL || strlen(user) == 0) { | |
855 luser = get_user_name(vmid, CHECK); | |
856 } | |
857 else { | |
858 luser = user; | |
859 } | |
860 | |
861 if (luser == NULL) { | |
862 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
863 "Could not map vmid to user Name"); | |
864 } | |
865 | |
866 char* dirname = get_user_tmp_dir(luser); | |
867 | |
868 // since we don't follow symbolic links when creating the backing | |
869 // store file, we don't follow them when attaching either. | |
870 // | |
871 if (!is_directory_secure(dirname)) { | |
872 FREE_C_HEAP_ARRAY(char, dirname); | |
873 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
874 "Process not found"); | |
875 } | |
876 | |
877 char* filename = get_sharedmem_filename(dirname, vmid); | |
878 | |
879 // copy heap memory to resource memory. the open_sharedmem_file | |
880 // method below need to use the filename, but could throw an | |
881 // exception. using a resource array prevents the leak that | |
882 // would otherwise occur. | |
883 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1); | |
884 strcpy(rfilename, filename); | |
885 | |
886 // free the c heap resources that are no longer needed | |
887 if (luser != user) FREE_C_HEAP_ARRAY(char, luser); | |
888 FREE_C_HEAP_ARRAY(char, dirname); | |
889 FREE_C_HEAP_ARRAY(char, filename); | |
890 | |
891 // open the shared memory file for the give vmid | |
892 fd = open_sharedmem_file(rfilename, file_flags, CHECK); | |
893 assert(fd != OS_ERR, "unexpected value"); | |
894 | |
895 if (*sizep == 0) { | |
896 size = sharedmem_filesize(fd, CHECK); | |
897 assert(size != 0, "unexpected size"); | |
898 } | |
899 | |
900 mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0); | |
901 | |
902 // attempt to close the file - restart if it gets interrupted, | |
903 // but ignore other failures | |
904 RESTARTABLE(::close(fd), result); | |
905 assert(result != OS_ERR, "could not close file"); | |
906 | |
907 if (mapAddress == MAP_FAILED) { | |
908 if (PrintMiscellaneous && Verbose) { | |
909 warning("mmap failed: %s\n", strerror(errno)); | |
910 } | |
911 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(), | |
912 "Could not map PerfMemory"); | |
913 } | |
914 | |
915 *addr = mapAddress; | |
916 *sizep = size; | |
917 | |
918 if (PerfTraceMemOps) { | |
919 tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at " | |
920 INTPTR_FORMAT "\n", size, vmid, (void*)mapAddress); | |
921 } | |
922 } | |
923 | |
924 | |
925 | |
926 | |
927 // create the PerfData memory region | |
928 // | |
929 // This method creates the memory region used to store performance | |
930 // data for the JVM. The memory may be created in standard or | |
931 // shared memory. | |
932 // | |
933 void PerfMemory::create_memory_region(size_t size) { | |
934 | |
935 if (PerfDisableSharedMem) { | |
936 // do not share the memory for the performance data. | |
937 _start = create_standard_memory(size); | |
938 } | |
939 else { | |
940 _start = create_shared_memory(size); | |
941 if (_start == NULL) { | |
942 | |
943 // creation of the shared memory region failed, attempt | |
944 // to create a contiguous, non-shared memory region instead. | |
945 // | |
946 if (PrintMiscellaneous && Verbose) { | |
947 warning("Reverting to non-shared PerfMemory region.\n"); | |
948 } | |
949 PerfDisableSharedMem = true; | |
950 _start = create_standard_memory(size); | |
951 } | |
952 } | |
953 | |
954 if (_start != NULL) _capacity = size; | |
955 | |
956 } | |
957 | |
958 // delete the PerfData memory region | |
959 // | |
960 // This method deletes the memory region used to store performance | |
961 // data for the JVM. The memory region indicated by the <address, size> | |
962 // tuple will be inaccessible after a call to this method. | |
963 // | |
964 void PerfMemory::delete_memory_region() { | |
965 | |
966 assert((start() != NULL && capacity() > 0), "verify proper state"); | |
967 | |
968 // If user specifies PerfDataSaveFile, it will save the performance data | |
969 // to the specified file name no matter whether PerfDataSaveToFile is specified | |
970 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag | |
971 // -XX:+PerfDataSaveToFile. | |
972 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) { | |
973 save_memory_to_file(start(), capacity()); | |
974 } | |
975 | |
976 if (PerfDisableSharedMem) { | |
977 delete_standard_memory(start(), capacity()); | |
978 } | |
979 else { | |
980 delete_shared_memory(start(), capacity()); | |
981 } | |
982 } | |
983 | |
984 // attach to the PerfData memory region for another JVM | |
985 // | |
986 // This method returns an <address, size> tuple that points to | |
987 // a memory buffer that is kept reasonably synchronized with | |
988 // the PerfData memory region for the indicated JVM. This | |
989 // buffer may be kept in synchronization via shared memory | |
990 // or some other mechanism that keeps the buffer updated. | |
991 // | |
992 // If the JVM chooses not to support the attachability feature, | |
993 // this method should throw an UnsupportedOperation exception. | |
994 // | |
995 // This implementation utilizes named shared memory to map | |
996 // the indicated process's PerfData memory region into this JVMs | |
997 // address space. | |
998 // | |
999 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, char** addrp, size_t* sizep, TRAPS) { | |
1000 | |
1001 if (vmid == 0 || vmid == os::current_process_id()) { | |
1002 *addrp = start(); | |
1003 *sizep = capacity(); | |
1004 return; | |
1005 } | |
1006 | |
1007 mmap_attach_shared(user, vmid, mode, addrp, sizep, CHECK); | |
1008 } | |
1009 | |
1010 // detach from the PerfData memory region of another JVM | |
1011 // | |
1012 // This method detaches the PerfData memory region of another | |
1013 // JVM, specified as an <address, size> tuple of a buffer | |
1014 // in this process's address space. This method may perform | |
1015 // arbitrary actions to accomplish the detachment. The memory | |
1016 // region specified by <address, size> will be inaccessible after | |
1017 // a call to this method. | |
1018 // | |
1019 // If the JVM chooses not to support the attachability feature, | |
1020 // this method should throw an UnsupportedOperation exception. | |
1021 // | |
1022 // This implementation utilizes named shared memory to detach | |
1023 // the indicated process's PerfData memory region from this | |
1024 // process's address space. | |
1025 // | |
1026 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) { | |
1027 | |
1028 assert(addr != 0, "address sanity check"); | |
1029 assert(bytes > 0, "capacity sanity check"); | |
1030 | |
1031 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) { | |
1032 // prevent accidental detachment of this process's PerfMemory region | |
1033 return; | |
1034 } | |
1035 | |
1036 unmap_shared(addr, bytes); | |
1037 } | |
1038 | |
1039 char* PerfMemory::backing_store_filename() { | |
1040 return backing_store_file_name; | |
1041 } |