Mercurial > hg > truffle
annotate src/os/linux/vm/perfMemory_linux.cpp @ 1972:f95d63e2154a
6989984: Use standard include model for Hospot
Summary: Replaced MakeDeps and the includeDB files with more standardized solutions.
Reviewed-by: coleenp, kvn, kamg
| author | stefank |
|---|---|
| date | Tue, 23 Nov 2010 13:22:55 -0800 |
| parents | c18cbe5936b8 |
| children | 02895c6a2f82 |
| rev | line source |
|---|---|
| 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 | |
| 638 return fd; | |
| 639 } | |
| 640 | |
| 641 // open the shared memory file for the given user and vmid. returns | |
| 642 // the file descriptor for the open file or -1 if the file could not | |
| 643 // be opened. | |
| 644 // | |
| 645 static int open_sharedmem_file(const char* filename, int oflags, TRAPS) { | |
| 646 | |
| 647 // open the file | |
| 648 int result; | |
| 649 RESTARTABLE(::open(filename, oflags), result); | |
| 650 if (result == OS_ERR) { | |
| 651 if (errno == ENOENT) { | |
| 652 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), | |
| 653 "Process not found"); | |
| 654 } | |
| 655 else if (errno == EACCES) { | |
| 656 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), | |
| 657 "Permission denied"); | |
| 658 } | |
| 659 else { | |
| 660 THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno)); | |
| 661 } | |
| 662 } | |
| 663 | |
| 664 return result; | |
| 665 } | |
| 666 | |
| 667 // create a named shared memory region. returns the address of the | |
| 668 // memory region on success or NULL on failure. A return value of | |
| 669 // NULL will ultimately disable the shared memory feature. | |
| 670 // | |
| 671 // On Solaris and Linux, the name space for shared memory objects | |
| 672 // is the file system name space. | |
| 673 // | |
| 674 // A monitoring application attaching to a JVM does not need to know | |
| 675 // the file system name of the shared memory object. However, it may | |
| 676 // be convenient for applications to discover the existence of newly | |
| 677 // created and terminating JVMs by watching the file system name space | |
| 678 // for files being created or removed. | |
| 679 // | |
| 680 static char* mmap_create_shared(size_t size) { | |
| 681 | |
| 682 int result; | |
| 683 int fd; | |
| 684 char* mapAddress; | |
| 685 | |
| 686 int vmid = os::current_process_id(); | |
| 687 | |
| 688 char* user_name = get_user_name(geteuid()); | |
| 689 | |
| 690 if (user_name == NULL) | |
| 691 return NULL; | |
| 692 | |
| 693 char* dirname = get_user_tmp_dir(user_name); | |
| 694 char* filename = get_sharedmem_filename(dirname, vmid); | |
| 695 | |
| 696 // cleanup any stale shared memory files | |
| 697 cleanup_sharedmem_resources(dirname); | |
| 698 | |
| 699 assert(((size > 0) && (size % os::vm_page_size() == 0)), | |
| 700 "unexpected PerfMemory region size"); | |
| 701 | |
| 702 fd = create_sharedmem_resources(dirname, filename, size); | |
| 703 | |
| 704 FREE_C_HEAP_ARRAY(char, user_name); | |
| 705 FREE_C_HEAP_ARRAY(char, dirname); | |
| 706 | |
| 707 if (fd == -1) { | |
| 708 FREE_C_HEAP_ARRAY(char, filename); | |
| 709 return NULL; | |
| 710 } | |
| 711 | |
| 712 mapAddress = (char*)::mmap((char*)0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); | |
| 713 | |
| 714 // attempt to close the file - restart it if it was interrupted, | |
| 715 // but ignore other failures | |
| 716 RESTARTABLE(::close(fd), result); | |
| 717 assert(result != OS_ERR, "could not close file"); | |
| 718 | |
| 719 if (mapAddress == MAP_FAILED) { | |
| 720 if (PrintMiscellaneous && Verbose) { | |
| 721 warning("mmap failed - %s\n", strerror(errno)); | |
| 722 } | |
| 723 remove_file(filename); | |
| 724 FREE_C_HEAP_ARRAY(char, filename); | |
| 725 return NULL; | |
| 726 } | |
| 727 | |
| 728 // save the file name for use in delete_shared_memory() | |
| 729 backing_store_file_name = filename; | |
| 730 | |
| 731 // clear the shared memory region | |
| 732 (void)::memset((void*) mapAddress, 0, size); | |
| 733 | |
| 734 return mapAddress; | |
| 735 } | |
| 736 | |
| 737 // release a named shared memory region | |
| 738 // | |
| 739 static void unmap_shared(char* addr, size_t bytes) { | |
| 740 os::release_memory(addr, bytes); | |
| 741 } | |
| 742 | |
| 743 // create the PerfData memory region in shared memory. | |
| 744 // | |
| 745 static char* create_shared_memory(size_t size) { | |
| 746 | |
| 747 // create the shared memory region. | |
| 748 return mmap_create_shared(size); | |
| 749 } | |
| 750 | |
| 751 // delete the shared PerfData memory region | |
| 752 // | |
| 753 static void delete_shared_memory(char* addr, size_t size) { | |
| 754 | |
| 755 // cleanup the persistent shared memory resources. since DestroyJavaVM does | |
| 756 // not support unloading of the JVM, unmapping of the memory resource is | |
| 757 // not performed. The memory will be reclaimed by the OS upon termination of | |
| 758 // the process. The backing store file is deleted from the file system. | |
| 759 | |
| 760 assert(!PerfDisableSharedMem, "shouldn't be here"); | |
| 761 | |
| 762 if (backing_store_file_name != NULL) { | |
| 763 remove_file(backing_store_file_name); | |
| 764 // Don't.. Free heap memory could deadlock os::abort() if it is called | |
| 765 // from signal handler. OS will reclaim the heap memory. | |
| 766 // FREE_C_HEAP_ARRAY(char, backing_store_file_name); | |
| 767 backing_store_file_name = NULL; | |
| 768 } | |
| 769 } | |
| 770 | |
| 771 // return the size of the file for the given file descriptor | |
| 772 // or 0 if it is not a valid size for a shared memory file | |
| 773 // | |
| 774 static size_t sharedmem_filesize(int fd, TRAPS) { | |
| 775 | |
| 776 struct stat statbuf; | |
| 777 int result; | |
| 778 | |
| 779 RESTARTABLE(::fstat(fd, &statbuf), result); | |
| 780 if (result == OS_ERR) { | |
| 781 if (PrintMiscellaneous && Verbose) { | |
| 782 warning("fstat failed: %s\n", strerror(errno)); | |
| 783 } | |
| 784 THROW_MSG_0(vmSymbols::java_io_IOException(), | |
| 785 "Could not determine PerfMemory size"); | |
| 786 } | |
| 787 | |
| 788 if ((statbuf.st_size == 0) || | |
| 789 ((size_t)statbuf.st_size % os::vm_page_size() != 0)) { | |
| 790 THROW_MSG_0(vmSymbols::java_lang_Exception(), | |
| 791 "Invalid PerfMemory size"); | |
| 792 } | |
| 793 | |
| 794 return (size_t)statbuf.st_size; | |
| 795 } | |
| 796 | |
| 797 // attach to a named shared memory region. | |
| 798 // | |
| 799 static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemoryMode mode, char** addr, size_t* sizep, TRAPS) { | |
| 800 | |
| 801 char* mapAddress; | |
| 802 int result; | |
| 803 int fd; | |
| 804 size_t size; | |
| 805 const char* luser = NULL; | |
| 806 | |
| 807 int mmap_prot; | |
| 808 int file_flags; | |
| 809 | |
| 810 ResourceMark rm; | |
| 811 | |
| 812 // map the high level access mode to the appropriate permission | |
| 813 // constructs for the file and the shared memory mapping. | |
| 814 if (mode == PerfMemory::PERF_MODE_RO) { | |
| 815 mmap_prot = PROT_READ; | |
| 816 file_flags = O_RDONLY; | |
| 817 } | |
| 818 else if (mode == PerfMemory::PERF_MODE_RW) { | |
| 819 #ifdef LATER | |
| 820 mmap_prot = PROT_READ | PROT_WRITE; | |
| 821 file_flags = O_RDWR; | |
| 822 #else | |
| 823 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
| 824 "Unsupported access mode"); | |
| 825 #endif | |
| 826 } | |
| 827 else { | |
| 828 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
| 829 "Illegal access mode"); | |
| 830 } | |
| 831 | |
| 832 if (user == NULL || strlen(user) == 0) { | |
| 833 luser = get_user_name(vmid, CHECK); | |
| 834 } | |
| 835 else { | |
| 836 luser = user; | |
| 837 } | |
| 838 | |
| 839 if (luser == NULL) { | |
| 840 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
| 841 "Could not map vmid to user Name"); | |
| 842 } | |
| 843 | |
| 844 char* dirname = get_user_tmp_dir(luser); | |
| 845 | |
| 846 // since we don't follow symbolic links when creating the backing | |
| 847 // store file, we don't follow them when attaching either. | |
| 848 // | |
| 849 if (!is_directory_secure(dirname)) { | |
| 850 FREE_C_HEAP_ARRAY(char, dirname); | |
| 851 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), | |
| 852 "Process not found"); | |
| 853 } | |
| 854 | |
| 855 char* filename = get_sharedmem_filename(dirname, vmid); | |
| 856 | |
| 857 // copy heap memory to resource memory. the open_sharedmem_file | |
| 858 // method below need to use the filename, but could throw an | |
| 859 // exception. using a resource array prevents the leak that | |
| 860 // would otherwise occur. | |
| 861 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1); | |
| 862 strcpy(rfilename, filename); | |
| 863 | |
| 864 // free the c heap resources that are no longer needed | |
| 865 if (luser != user) FREE_C_HEAP_ARRAY(char, luser); | |
| 866 FREE_C_HEAP_ARRAY(char, dirname); | |
| 867 FREE_C_HEAP_ARRAY(char, filename); | |
| 868 | |
| 869 // open the shared memory file for the give vmid | |
| 870 fd = open_sharedmem_file(rfilename, file_flags, CHECK); | |
| 871 assert(fd != OS_ERR, "unexpected value"); | |
| 872 | |
| 873 if (*sizep == 0) { | |
| 874 size = sharedmem_filesize(fd, CHECK); | |
| 875 assert(size != 0, "unexpected size"); | |
| 876 } | |
| 877 | |
| 878 mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0); | |
| 879 | |
| 880 // attempt to close the file - restart if it gets interrupted, | |
| 881 // but ignore other failures | |
| 882 RESTARTABLE(::close(fd), result); | |
| 883 assert(result != OS_ERR, "could not close file"); | |
| 884 | |
| 885 if (mapAddress == MAP_FAILED) { | |
| 886 if (PrintMiscellaneous && Verbose) { | |
| 887 warning("mmap failed: %s\n", strerror(errno)); | |
| 888 } | |
| 889 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(), | |
| 890 "Could not map PerfMemory"); | |
| 891 } | |
| 892 | |
| 893 *addr = mapAddress; | |
| 894 *sizep = size; | |
| 895 | |
| 896 if (PerfTraceMemOps) { | |
| 897 tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at " | |
| 898 INTPTR_FORMAT "\n", size, vmid, (void*)mapAddress); | |
| 899 } | |
| 900 } | |
| 901 | |
| 902 | |
| 903 | |
| 904 | |
| 905 // create the PerfData memory region | |
| 906 // | |
| 907 // This method creates the memory region used to store performance | |
| 908 // data for the JVM. The memory may be created in standard or | |
| 909 // shared memory. | |
| 910 // | |
| 911 void PerfMemory::create_memory_region(size_t size) { | |
| 912 | |
| 913 if (PerfDisableSharedMem) { | |
| 914 // do not share the memory for the performance data. | |
| 915 _start = create_standard_memory(size); | |
| 916 } | |
| 917 else { | |
| 918 _start = create_shared_memory(size); | |
| 919 if (_start == NULL) { | |
| 920 | |
| 921 // creation of the shared memory region failed, attempt | |
| 922 // to create a contiguous, non-shared memory region instead. | |
| 923 // | |
| 924 if (PrintMiscellaneous && Verbose) { | |
| 925 warning("Reverting to non-shared PerfMemory region.\n"); | |
| 926 } | |
| 927 PerfDisableSharedMem = true; | |
| 928 _start = create_standard_memory(size); | |
| 929 } | |
| 930 } | |
| 931 | |
| 932 if (_start != NULL) _capacity = size; | |
| 933 | |
| 934 } | |
| 935 | |
| 936 // delete the PerfData memory region | |
| 937 // | |
| 938 // This method deletes the memory region used to store performance | |
| 939 // data for the JVM. The memory region indicated by the <address, size> | |
| 940 // tuple will be inaccessible after a call to this method. | |
| 941 // | |
| 942 void PerfMemory::delete_memory_region() { | |
| 943 | |
| 944 assert((start() != NULL && capacity() > 0), "verify proper state"); | |
| 945 | |
| 946 // If user specifies PerfDataSaveFile, it will save the performance data | |
| 947 // to the specified file name no matter whether PerfDataSaveToFile is specified | |
| 948 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag | |
| 949 // -XX:+PerfDataSaveToFile. | |
| 950 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) { | |
| 951 save_memory_to_file(start(), capacity()); | |
| 952 } | |
| 953 | |
| 954 if (PerfDisableSharedMem) { | |
| 955 delete_standard_memory(start(), capacity()); | |
| 956 } | |
| 957 else { | |
| 958 delete_shared_memory(start(), capacity()); | |
| 959 } | |
| 960 } | |
| 961 | |
| 962 // attach to the PerfData memory region for another JVM | |
| 963 // | |
| 964 // This method returns an <address, size> tuple that points to | |
| 965 // a memory buffer that is kept reasonably synchronized with | |
| 966 // the PerfData memory region for the indicated JVM. This | |
| 967 // buffer may be kept in synchronization via shared memory | |
| 968 // or some other mechanism that keeps the buffer updated. | |
| 969 // | |
| 970 // If the JVM chooses not to support the attachability feature, | |
| 971 // this method should throw an UnsupportedOperation exception. | |
| 972 // | |
| 973 // This implementation utilizes named shared memory to map | |
| 974 // the indicated process's PerfData memory region into this JVMs | |
| 975 // address space. | |
| 976 // | |
| 977 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, char** addrp, size_t* sizep, TRAPS) { | |
| 978 | |
| 979 if (vmid == 0 || vmid == os::current_process_id()) { | |
| 980 *addrp = start(); | |
| 981 *sizep = capacity(); | |
| 982 return; | |
| 983 } | |
| 984 | |
| 985 mmap_attach_shared(user, vmid, mode, addrp, sizep, CHECK); | |
| 986 } | |
| 987 | |
| 988 // detach from the PerfData memory region of another JVM | |
| 989 // | |
| 990 // This method detaches the PerfData memory region of another | |
| 991 // JVM, specified as an <address, size> tuple of a buffer | |
| 992 // in this process's address space. This method may perform | |
| 993 // arbitrary actions to accomplish the detachment. The memory | |
| 994 // region specified by <address, size> will be inaccessible after | |
| 995 // a call to this method. | |
| 996 // | |
| 997 // If the JVM chooses not to support the attachability feature, | |
| 998 // this method should throw an UnsupportedOperation exception. | |
| 999 // | |
| 1000 // This implementation utilizes named shared memory to detach | |
| 1001 // the indicated process's PerfData memory region from this | |
| 1002 // process's address space. | |
| 1003 // | |
| 1004 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) { | |
| 1005 | |
| 1006 assert(addr != 0, "address sanity check"); | |
| 1007 assert(bytes > 0, "capacity sanity check"); | |
| 1008 | |
| 1009 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) { | |
| 1010 // prevent accidental detachment of this process's PerfMemory region | |
| 1011 return; | |
| 1012 } | |
| 1013 | |
| 1014 unmap_shared(addr, bytes); | |
| 1015 } | |
| 1016 | |
| 1017 char* PerfMemory::backing_store_filename() { | |
| 1018 return backing_store_file_name; | |
| 1019 } |