1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/os/bsd/vm/perfMemory_bsd.cpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,1049 @@
1.4 +/*
1.5 + * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#include "precompiled.hpp"
1.29 +#include "classfile/vmSymbols.hpp"
1.30 +#include "memory/allocation.inline.hpp"
1.31 +#include "memory/resourceArea.hpp"
1.32 +#include "oops/oop.inline.hpp"
1.33 +#include "os_bsd.inline.hpp"
1.34 +#include "runtime/handles.inline.hpp"
1.35 +#include "runtime/perfMemory.hpp"
1.36 +#include "services/memTracker.hpp"
1.37 +#include "utilities/exceptions.hpp"
1.38 +
1.39 +// put OS-includes here
1.40 +# include <sys/types.h>
1.41 +# include <sys/mman.h>
1.42 +# include <errno.h>
1.43 +# include <stdio.h>
1.44 +# include <unistd.h>
1.45 +# include <sys/stat.h>
1.46 +# include <signal.h>
1.47 +# include <pwd.h>
1.48 +
1.49 +static char* backing_store_file_name = NULL; // name of the backing store
1.50 + // file, if successfully created.
1.51 +
1.52 +// Standard Memory Implementation Details
1.53 +
1.54 +// create the PerfData memory region in standard memory.
1.55 +//
1.56 +static char* create_standard_memory(size_t size) {
1.57 +
1.58 + // allocate an aligned chuck of memory
1.59 + char* mapAddress = os::reserve_memory(size);
1.60 +
1.61 + if (mapAddress == NULL) {
1.62 + return NULL;
1.63 + }
1.64 +
1.65 + // commit memory
1.66 + if (!os::commit_memory(mapAddress, size, !ExecMem)) {
1.67 + if (PrintMiscellaneous && Verbose) {
1.68 + warning("Could not commit PerfData memory\n");
1.69 + }
1.70 + os::release_memory(mapAddress, size);
1.71 + return NULL;
1.72 + }
1.73 +
1.74 + return mapAddress;
1.75 +}
1.76 +
1.77 +// delete the PerfData memory region
1.78 +//
1.79 +static void delete_standard_memory(char* addr, size_t size) {
1.80 +
1.81 + // there are no persistent external resources to cleanup for standard
1.82 + // memory. since DestroyJavaVM does not support unloading of the JVM,
1.83 + // cleanup of the memory resource is not performed. The memory will be
1.84 + // reclaimed by the OS upon termination of the process.
1.85 + //
1.86 + return;
1.87 +}
1.88 +
1.89 +// save the specified memory region to the given file
1.90 +//
1.91 +// Note: this function might be called from signal handler (by os::abort()),
1.92 +// don't allocate heap memory.
1.93 +//
1.94 +static void save_memory_to_file(char* addr, size_t size) {
1.95 +
1.96 + const char* destfile = PerfMemory::get_perfdata_file_path();
1.97 + assert(destfile[0] != '\0', "invalid PerfData file path");
1.98 +
1.99 + int result;
1.100 +
1.101 + RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE),
1.102 + result);;
1.103 + if (result == OS_ERR) {
1.104 + if (PrintMiscellaneous && Verbose) {
1.105 + warning("Could not create Perfdata save file: %s: %s\n",
1.106 + destfile, strerror(errno));
1.107 + }
1.108 + } else {
1.109 + int fd = result;
1.110 +
1.111 + for (size_t remaining = size; remaining > 0;) {
1.112 +
1.113 + RESTARTABLE(::write(fd, addr, remaining), result);
1.114 + if (result == OS_ERR) {
1.115 + if (PrintMiscellaneous && Verbose) {
1.116 + warning("Could not write Perfdata save file: %s: %s\n",
1.117 + destfile, strerror(errno));
1.118 + }
1.119 + break;
1.120 + }
1.121 +
1.122 + remaining -= (size_t)result;
1.123 + addr += result;
1.124 + }
1.125 +
1.126 + result = ::close(fd);
1.127 + if (PrintMiscellaneous && Verbose) {
1.128 + if (result == OS_ERR) {
1.129 + warning("Could not close %s: %s\n", destfile, strerror(errno));
1.130 + }
1.131 + }
1.132 + }
1.133 + FREE_C_HEAP_ARRAY(char, destfile, mtInternal);
1.134 +}
1.135 +
1.136 +
1.137 +// Shared Memory Implementation Details
1.138 +
1.139 +// Note: the solaris and bsd shared memory implementation uses the mmap
1.140 +// interface with a backing store file to implement named shared memory.
1.141 +// Using the file system as the name space for shared memory allows a
1.142 +// common name space to be supported across a variety of platforms. It
1.143 +// also provides a name space that Java applications can deal with through
1.144 +// simple file apis.
1.145 +//
1.146 +// The solaris and bsd implementations store the backing store file in
1.147 +// a user specific temporary directory located in the /tmp file system,
1.148 +// which is always a local file system and is sometimes a RAM based file
1.149 +// system.
1.150 +
1.151 +// return the user specific temporary directory name.
1.152 +//
1.153 +// the caller is expected to free the allocated memory.
1.154 +//
1.155 +static char* get_user_tmp_dir(const char* user) {
1.156 +
1.157 + const char* tmpdir = os::get_temp_directory();
1.158 + const char* perfdir = PERFDATA_NAME;
1.159 + size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3;
1.160 + char* dirname = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
1.161 +
1.162 + // construct the path name to user specific tmp directory
1.163 + snprintf(dirname, nbytes, "%s/%s_%s", tmpdir, perfdir, user);
1.164 +
1.165 + return dirname;
1.166 +}
1.167 +
1.168 +// convert the given file name into a process id. if the file
1.169 +// does not meet the file naming constraints, return 0.
1.170 +//
1.171 +static pid_t filename_to_pid(const char* filename) {
1.172 +
1.173 + // a filename that doesn't begin with a digit is not a
1.174 + // candidate for conversion.
1.175 + //
1.176 + if (!isdigit(*filename)) {
1.177 + return 0;
1.178 + }
1.179 +
1.180 + // check if file name can be converted to an integer without
1.181 + // any leftover characters.
1.182 + //
1.183 + char* remainder = NULL;
1.184 + errno = 0;
1.185 + pid_t pid = (pid_t)strtol(filename, &remainder, 10);
1.186 +
1.187 + if (errno != 0) {
1.188 + return 0;
1.189 + }
1.190 +
1.191 + // check for left over characters. If any, then the filename is
1.192 + // not a candidate for conversion.
1.193 + //
1.194 + if (remainder != NULL && *remainder != '\0') {
1.195 + return 0;
1.196 + }
1.197 +
1.198 + // successful conversion, return the pid
1.199 + return pid;
1.200 +}
1.201 +
1.202 +
1.203 +// check if the given path is considered a secure directory for
1.204 +// the backing store files. Returns true if the directory exists
1.205 +// and is considered a secure location. Returns false if the path
1.206 +// is a symbolic link or if an error occurred.
1.207 +//
1.208 +static bool is_directory_secure(const char* path) {
1.209 + struct stat statbuf;
1.210 + int result = 0;
1.211 +
1.212 + RESTARTABLE(::lstat(path, &statbuf), result);
1.213 + if (result == OS_ERR) {
1.214 + return false;
1.215 + }
1.216 +
1.217 + // the path exists, now check it's mode
1.218 + if (S_ISLNK(statbuf.st_mode) || !S_ISDIR(statbuf.st_mode)) {
1.219 + // the path represents a link or some non-directory file type,
1.220 + // which is not what we expected. declare it insecure.
1.221 + //
1.222 + return false;
1.223 + }
1.224 + else {
1.225 + // we have an existing directory, check if the permissions are safe.
1.226 + //
1.227 + if ((statbuf.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
1.228 + // the directory is open for writing and could be subjected
1.229 + // to a symlnk attack. declare it insecure.
1.230 + //
1.231 + return false;
1.232 + }
1.233 + }
1.234 + return true;
1.235 +}
1.236 +
1.237 +
1.238 +// return the user name for the given user id
1.239 +//
1.240 +// the caller is expected to free the allocated memory.
1.241 +//
1.242 +static char* get_user_name(uid_t uid) {
1.243 +
1.244 + struct passwd pwent;
1.245 +
1.246 + // determine the max pwbuf size from sysconf, and hardcode
1.247 + // a default if this not available through sysconf.
1.248 + //
1.249 + long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
1.250 + if (bufsize == -1)
1.251 + bufsize = 1024;
1.252 +
1.253 + char* pwbuf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
1.254 +
1.255 + // POSIX interface to getpwuid_r is used on LINUX
1.256 + struct passwd* p;
1.257 + int result = getpwuid_r(uid, &pwent, pwbuf, (size_t)bufsize, &p);
1.258 +
1.259 + if (result != 0 || p == NULL || p->pw_name == NULL || *(p->pw_name) == '\0') {
1.260 + if (PrintMiscellaneous && Verbose) {
1.261 + if (result != 0) {
1.262 + warning("Could not retrieve passwd entry: %s\n",
1.263 + strerror(result));
1.264 + }
1.265 + else if (p == NULL) {
1.266 + // this check is added to protect against an observed problem
1.267 + // with getpwuid_r() on RedHat 9 where getpwuid_r returns 0,
1.268 + // indicating success, but has p == NULL. This was observed when
1.269 + // inserting a file descriptor exhaustion fault prior to the call
1.270 + // getpwuid_r() call. In this case, error is set to the appropriate
1.271 + // error condition, but this is undocumented behavior. This check
1.272 + // is safe under any condition, but the use of errno in the output
1.273 + // message may result in an erroneous message.
1.274 + // Bug Id 89052 was opened with RedHat.
1.275 + //
1.276 + warning("Could not retrieve passwd entry: %s\n",
1.277 + strerror(errno));
1.278 + }
1.279 + else {
1.280 + warning("Could not determine user name: %s\n",
1.281 + p->pw_name == NULL ? "pw_name = NULL" :
1.282 + "pw_name zero length");
1.283 + }
1.284 + }
1.285 + FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal);
1.286 + return NULL;
1.287 + }
1.288 +
1.289 + char* user_name = NEW_C_HEAP_ARRAY(char, strlen(p->pw_name) + 1, mtInternal);
1.290 + strcpy(user_name, p->pw_name);
1.291 +
1.292 + FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal);
1.293 + return user_name;
1.294 +}
1.295 +
1.296 +// return the name of the user that owns the process identified by vmid.
1.297 +//
1.298 +// This method uses a slow directory search algorithm to find the backing
1.299 +// store file for the specified vmid and returns the user name, as determined
1.300 +// by the user name suffix of the hsperfdata_<username> directory name.
1.301 +//
1.302 +// the caller is expected to free the allocated memory.
1.303 +//
1.304 +static char* get_user_name_slow(int vmid, TRAPS) {
1.305 +
1.306 + // short circuit the directory search if the process doesn't even exist.
1.307 + if (kill(vmid, 0) == OS_ERR) {
1.308 + if (errno == ESRCH) {
1.309 + THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
1.310 + "Process not found");
1.311 + }
1.312 + else /* EPERM */ {
1.313 + THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
1.314 + }
1.315 + }
1.316 +
1.317 + // directory search
1.318 + char* oldest_user = NULL;
1.319 + time_t oldest_ctime = 0;
1.320 +
1.321 + const char* tmpdirname = os::get_temp_directory();
1.322 +
1.323 + DIR* tmpdirp = os::opendir(tmpdirname);
1.324 +
1.325 + if (tmpdirp == NULL) {
1.326 + return NULL;
1.327 + }
1.328 +
1.329 + // for each entry in the directory that matches the pattern hsperfdata_*,
1.330 + // open the directory and check if the file for the given vmid exists.
1.331 + // The file with the expected name and the latest creation date is used
1.332 + // to determine the user name for the process id.
1.333 + //
1.334 + struct dirent* dentry;
1.335 + char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname), mtInternal);
1.336 + errno = 0;
1.337 + while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) {
1.338 +
1.339 + // check if the directory entry is a hsperfdata file
1.340 + if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
1.341 + continue;
1.342 + }
1.343 +
1.344 + char* usrdir_name = NEW_C_HEAP_ARRAY(char,
1.345 + strlen(tmpdirname) + strlen(dentry->d_name) + 2, mtInternal);
1.346 + strcpy(usrdir_name, tmpdirname);
1.347 + strcat(usrdir_name, "/");
1.348 + strcat(usrdir_name, dentry->d_name);
1.349 +
1.350 + DIR* subdirp = os::opendir(usrdir_name);
1.351 +
1.352 + if (subdirp == NULL) {
1.353 + FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
1.354 + continue;
1.355 + }
1.356 +
1.357 + // Since we don't create the backing store files in directories
1.358 + // pointed to by symbolic links, we also don't follow them when
1.359 + // looking for the files. We check for a symbolic link after the
1.360 + // call to opendir in order to eliminate a small window where the
1.361 + // symlink can be exploited.
1.362 + //
1.363 + if (!is_directory_secure(usrdir_name)) {
1.364 + FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
1.365 + os::closedir(subdirp);
1.366 + continue;
1.367 + }
1.368 +
1.369 + struct dirent* udentry;
1.370 + char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name), mtInternal);
1.371 + errno = 0;
1.372 + while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
1.373 +
1.374 + if (filename_to_pid(udentry->d_name) == vmid) {
1.375 + struct stat statbuf;
1.376 + int result;
1.377 +
1.378 + char* filename = NEW_C_HEAP_ARRAY(char,
1.379 + strlen(usrdir_name) + strlen(udentry->d_name) + 2, mtInternal);
1.380 +
1.381 + strcpy(filename, usrdir_name);
1.382 + strcat(filename, "/");
1.383 + strcat(filename, udentry->d_name);
1.384 +
1.385 + // don't follow symbolic links for the file
1.386 + RESTARTABLE(::lstat(filename, &statbuf), result);
1.387 + if (result == OS_ERR) {
1.388 + FREE_C_HEAP_ARRAY(char, filename, mtInternal);
1.389 + continue;
1.390 + }
1.391 +
1.392 + // skip over files that are not regular files.
1.393 + if (!S_ISREG(statbuf.st_mode)) {
1.394 + FREE_C_HEAP_ARRAY(char, filename, mtInternal);
1.395 + continue;
1.396 + }
1.397 +
1.398 + // compare and save filename with latest creation time
1.399 + if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) {
1.400 +
1.401 + if (statbuf.st_ctime > oldest_ctime) {
1.402 + char* user = strchr(dentry->d_name, '_') + 1;
1.403 +
1.404 + if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user, mtInternal);
1.405 + oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
1.406 +
1.407 + strcpy(oldest_user, user);
1.408 + oldest_ctime = statbuf.st_ctime;
1.409 + }
1.410 + }
1.411 +
1.412 + FREE_C_HEAP_ARRAY(char, filename, mtInternal);
1.413 + }
1.414 + }
1.415 + os::closedir(subdirp);
1.416 + FREE_C_HEAP_ARRAY(char, udbuf, mtInternal);
1.417 + FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
1.418 + }
1.419 + os::closedir(tmpdirp);
1.420 + FREE_C_HEAP_ARRAY(char, tdbuf, mtInternal);
1.421 +
1.422 + return(oldest_user);
1.423 +}
1.424 +
1.425 +// return the name of the user that owns the JVM indicated by the given vmid.
1.426 +//
1.427 +static char* get_user_name(int vmid, TRAPS) {
1.428 + return get_user_name_slow(vmid, CHECK_NULL);
1.429 +}
1.430 +
1.431 +// return the file name of the backing store file for the named
1.432 +// shared memory region for the given user name and vmid.
1.433 +//
1.434 +// the caller is expected to free the allocated memory.
1.435 +//
1.436 +static char* get_sharedmem_filename(const char* dirname, int vmid) {
1.437 +
1.438 + // add 2 for the file separator and a null terminator.
1.439 + size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
1.440 +
1.441 + char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
1.442 + snprintf(name, nbytes, "%s/%d", dirname, vmid);
1.443 +
1.444 + return name;
1.445 +}
1.446 +
1.447 +
1.448 +// remove file
1.449 +//
1.450 +// this method removes the file specified by the given path
1.451 +//
1.452 +static void remove_file(const char* path) {
1.453 +
1.454 + int result;
1.455 +
1.456 + // if the file is a directory, the following unlink will fail. since
1.457 + // we don't expect to find directories in the user temp directory, we
1.458 + // won't try to handle this situation. even if accidentially or
1.459 + // maliciously planted, the directory's presence won't hurt anything.
1.460 + //
1.461 + RESTARTABLE(::unlink(path), result);
1.462 + if (PrintMiscellaneous && Verbose && result == OS_ERR) {
1.463 + if (errno != ENOENT) {
1.464 + warning("Could not unlink shared memory backing"
1.465 + " store file %s : %s\n", path, strerror(errno));
1.466 + }
1.467 + }
1.468 +}
1.469 +
1.470 +
1.471 +// remove file
1.472 +//
1.473 +// this method removes the file with the given file name in the
1.474 +// named directory.
1.475 +//
1.476 +static void remove_file(const char* dirname, const char* filename) {
1.477 +
1.478 + size_t nbytes = strlen(dirname) + strlen(filename) + 2;
1.479 + char* path = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
1.480 +
1.481 + strcpy(path, dirname);
1.482 + strcat(path, "/");
1.483 + strcat(path, filename);
1.484 +
1.485 + remove_file(path);
1.486 +
1.487 + FREE_C_HEAP_ARRAY(char, path, mtInternal);
1.488 +}
1.489 +
1.490 +
1.491 +// cleanup stale shared memory resources
1.492 +//
1.493 +// This method attempts to remove all stale shared memory files in
1.494 +// the named user temporary directory. It scans the named directory
1.495 +// for files matching the pattern ^$[0-9]*$. For each file found, the
1.496 +// process id is extracted from the file name and a test is run to
1.497 +// determine if the process is alive. If the process is not alive,
1.498 +// any stale file resources are removed.
1.499 +//
1.500 +static void cleanup_sharedmem_resources(const char* dirname) {
1.501 +
1.502 + // open the user temp directory
1.503 + DIR* dirp = os::opendir(dirname);
1.504 +
1.505 + if (dirp == NULL) {
1.506 + // directory doesn't exist, so there is nothing to cleanup
1.507 + return;
1.508 + }
1.509 +
1.510 + if (!is_directory_secure(dirname)) {
1.511 + // the directory is not a secure directory
1.512 + return;
1.513 + }
1.514 +
1.515 + // for each entry in the directory that matches the expected file
1.516 + // name pattern, determine if the file resources are stale and if
1.517 + // so, remove the file resources. Note, instrumented HotSpot processes
1.518 + // for this user may start and/or terminate during this search and
1.519 + // remove or create new files in this directory. The behavior of this
1.520 + // loop under these conditions is dependent upon the implementation of
1.521 + // opendir/readdir.
1.522 + //
1.523 + struct dirent* entry;
1.524 + char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname), mtInternal);
1.525 + errno = 0;
1.526 + while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) {
1.527 +
1.528 + pid_t pid = filename_to_pid(entry->d_name);
1.529 +
1.530 + if (pid == 0) {
1.531 +
1.532 + if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
1.533 +
1.534 + // attempt to remove all unexpected files, except "." and ".."
1.535 + remove_file(dirname, entry->d_name);
1.536 + }
1.537 +
1.538 + errno = 0;
1.539 + continue;
1.540 + }
1.541 +
1.542 + // we now have a file name that converts to a valid integer
1.543 + // that could represent a process id . if this process id
1.544 + // matches the current process id or the process is not running,
1.545 + // then remove the stale file resources.
1.546 + //
1.547 + // process liveness is detected by sending signal number 0 to
1.548 + // the process id (see kill(2)). if kill determines that the
1.549 + // process does not exist, then the file resources are removed.
1.550 + // if kill determines that that we don't have permission to
1.551 + // signal the process, then the file resources are assumed to
1.552 + // be stale and are removed because the resources for such a
1.553 + // process should be in a different user specific directory.
1.554 + //
1.555 + if ((pid == os::current_process_id()) ||
1.556 + (kill(pid, 0) == OS_ERR && (errno == ESRCH || errno == EPERM))) {
1.557 +
1.558 + remove_file(dirname, entry->d_name);
1.559 + }
1.560 + errno = 0;
1.561 + }
1.562 + os::closedir(dirp);
1.563 + FREE_C_HEAP_ARRAY(char, dbuf, mtInternal);
1.564 +}
1.565 +
1.566 +// make the user specific temporary directory. Returns true if
1.567 +// the directory exists and is secure upon return. Returns false
1.568 +// if the directory exists but is either a symlink, is otherwise
1.569 +// insecure, or if an error occurred.
1.570 +//
1.571 +static bool make_user_tmp_dir(const char* dirname) {
1.572 +
1.573 + // create the directory with 0755 permissions. note that the directory
1.574 + // will be owned by euid::egid, which may not be the same as uid::gid.
1.575 + //
1.576 + if (mkdir(dirname, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) == OS_ERR) {
1.577 + if (errno == EEXIST) {
1.578 + // The directory already exists and was probably created by another
1.579 + // JVM instance. However, this could also be the result of a
1.580 + // deliberate symlink. Verify that the existing directory is safe.
1.581 + //
1.582 + if (!is_directory_secure(dirname)) {
1.583 + // directory is not secure
1.584 + if (PrintMiscellaneous && Verbose) {
1.585 + warning("%s directory is insecure\n", dirname);
1.586 + }
1.587 + return false;
1.588 + }
1.589 + }
1.590 + else {
1.591 + // we encountered some other failure while attempting
1.592 + // to create the directory
1.593 + //
1.594 + if (PrintMiscellaneous && Verbose) {
1.595 + warning("could not create directory %s: %s\n",
1.596 + dirname, strerror(errno));
1.597 + }
1.598 + return false;
1.599 + }
1.600 + }
1.601 + return true;
1.602 +}
1.603 +
1.604 +// create the shared memory file resources
1.605 +//
1.606 +// This method creates the shared memory file with the given size
1.607 +// This method also creates the user specific temporary directory, if
1.608 +// it does not yet exist.
1.609 +//
1.610 +static int create_sharedmem_resources(const char* dirname, const char* filename, size_t size) {
1.611 +
1.612 + // make the user temporary directory
1.613 + if (!make_user_tmp_dir(dirname)) {
1.614 + // could not make/find the directory or the found directory
1.615 + // was not secure
1.616 + return -1;
1.617 + }
1.618 +
1.619 + int result;
1.620 +
1.621 + RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_TRUNC, S_IREAD|S_IWRITE), result);
1.622 + if (result == OS_ERR) {
1.623 + if (PrintMiscellaneous && Verbose) {
1.624 + warning("could not create file %s: %s\n", filename, strerror(errno));
1.625 + }
1.626 + return -1;
1.627 + }
1.628 +
1.629 + // save the file descriptor
1.630 + int fd = result;
1.631 +
1.632 + // set the file size
1.633 + RESTARTABLE(::ftruncate(fd, (off_t)size), result);
1.634 + if (result == OS_ERR) {
1.635 + if (PrintMiscellaneous && Verbose) {
1.636 + warning("could not set shared memory file size: %s\n", strerror(errno));
1.637 + }
1.638 + ::close(fd);
1.639 + return -1;
1.640 + }
1.641 +
1.642 + // Verify that we have enough disk space for this file.
1.643 + // We'll get random SIGBUS crashes on memory accesses if
1.644 + // we don't.
1.645 +
1.646 + for (size_t seekpos = 0; seekpos < size; seekpos += os::vm_page_size()) {
1.647 + int zero_int = 0;
1.648 + result = (int)os::seek_to_file_offset(fd, (jlong)(seekpos));
1.649 + if (result == -1 ) break;
1.650 + RESTARTABLE(::write(fd, &zero_int, 1), result);
1.651 + if (result != 1) {
1.652 + if (errno == ENOSPC) {
1.653 + warning("Insufficient space for shared memory file:\n %s\nTry using the -Djava.io.tmpdir= option to select an alternate temp location.\n", filename);
1.654 + }
1.655 + break;
1.656 + }
1.657 + }
1.658 +
1.659 + if (result != -1) {
1.660 + return fd;
1.661 + } else {
1.662 + ::close(fd);
1.663 + return -1;
1.664 + }
1.665 +}
1.666 +
1.667 +// open the shared memory file for the given user and vmid. returns
1.668 +// the file descriptor for the open file or -1 if the file could not
1.669 +// be opened.
1.670 +//
1.671 +static int open_sharedmem_file(const char* filename, int oflags, TRAPS) {
1.672 +
1.673 + // open the file
1.674 + int result;
1.675 + RESTARTABLE(::open(filename, oflags), result);
1.676 + if (result == OS_ERR) {
1.677 + if (errno == ENOENT) {
1.678 + THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),
1.679 + "Process not found", OS_ERR);
1.680 + }
1.681 + else if (errno == EACCES) {
1.682 + THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),
1.683 + "Permission denied", OS_ERR);
1.684 + }
1.685 + else {
1.686 + THROW_MSG_(vmSymbols::java_io_IOException(), strerror(errno), OS_ERR);
1.687 + }
1.688 + }
1.689 +
1.690 + return result;
1.691 +}
1.692 +
1.693 +// create a named shared memory region. returns the address of the
1.694 +// memory region on success or NULL on failure. A return value of
1.695 +// NULL will ultimately disable the shared memory feature.
1.696 +//
1.697 +// On Solaris and Bsd, the name space for shared memory objects
1.698 +// is the file system name space.
1.699 +//
1.700 +// A monitoring application attaching to a JVM does not need to know
1.701 +// the file system name of the shared memory object. However, it may
1.702 +// be convenient for applications to discover the existence of newly
1.703 +// created and terminating JVMs by watching the file system name space
1.704 +// for files being created or removed.
1.705 +//
1.706 +static char* mmap_create_shared(size_t size) {
1.707 +
1.708 + int result;
1.709 + int fd;
1.710 + char* mapAddress;
1.711 +
1.712 + int vmid = os::current_process_id();
1.713 +
1.714 + char* user_name = get_user_name(geteuid());
1.715 +
1.716 + if (user_name == NULL)
1.717 + return NULL;
1.718 +
1.719 + char* dirname = get_user_tmp_dir(user_name);
1.720 + char* filename = get_sharedmem_filename(dirname, vmid);
1.721 +
1.722 + // cleanup any stale shared memory files
1.723 + cleanup_sharedmem_resources(dirname);
1.724 +
1.725 + assert(((size > 0) && (size % os::vm_page_size() == 0)),
1.726 + "unexpected PerfMemory region size");
1.727 +
1.728 + fd = create_sharedmem_resources(dirname, filename, size);
1.729 +
1.730 + FREE_C_HEAP_ARRAY(char, user_name, mtInternal);
1.731 + FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
1.732 +
1.733 + if (fd == -1) {
1.734 + FREE_C_HEAP_ARRAY(char, filename, mtInternal);
1.735 + return NULL;
1.736 + }
1.737 +
1.738 + mapAddress = (char*)::mmap((char*)0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
1.739 +
1.740 + result = ::close(fd);
1.741 + assert(result != OS_ERR, "could not close file");
1.742 +
1.743 + if (mapAddress == MAP_FAILED) {
1.744 + if (PrintMiscellaneous && Verbose) {
1.745 + warning("mmap failed - %s\n", strerror(errno));
1.746 + }
1.747 + remove_file(filename);
1.748 + FREE_C_HEAP_ARRAY(char, filename, mtInternal);
1.749 + return NULL;
1.750 + }
1.751 +
1.752 + // save the file name for use in delete_shared_memory()
1.753 + backing_store_file_name = filename;
1.754 +
1.755 + // clear the shared memory region
1.756 + (void)::memset((void*) mapAddress, 0, size);
1.757 +
1.758 + // it does not go through os api, the operation has to record from here
1.759 + MemTracker::record_virtual_memory_reserve((address)mapAddress, size, mtInternal, CURRENT_PC);
1.760 +
1.761 + return mapAddress;
1.762 +}
1.763 +
1.764 +// release a named shared memory region
1.765 +//
1.766 +static void unmap_shared(char* addr, size_t bytes) {
1.767 + os::release_memory(addr, bytes);
1.768 +}
1.769 +
1.770 +// create the PerfData memory region in shared memory.
1.771 +//
1.772 +static char* create_shared_memory(size_t size) {
1.773 +
1.774 + // create the shared memory region.
1.775 + return mmap_create_shared(size);
1.776 +}
1.777 +
1.778 +// delete the shared PerfData memory region
1.779 +//
1.780 +static void delete_shared_memory(char* addr, size_t size) {
1.781 +
1.782 + // cleanup the persistent shared memory resources. since DestroyJavaVM does
1.783 + // not support unloading of the JVM, unmapping of the memory resource is
1.784 + // not performed. The memory will be reclaimed by the OS upon termination of
1.785 + // the process. The backing store file is deleted from the file system.
1.786 +
1.787 + assert(!PerfDisableSharedMem, "shouldn't be here");
1.788 +
1.789 + if (backing_store_file_name != NULL) {
1.790 + remove_file(backing_store_file_name);
1.791 + // Don't.. Free heap memory could deadlock os::abort() if it is called
1.792 + // from signal handler. OS will reclaim the heap memory.
1.793 + // FREE_C_HEAP_ARRAY(char, backing_store_file_name);
1.794 + backing_store_file_name = NULL;
1.795 + }
1.796 +}
1.797 +
1.798 +// return the size of the file for the given file descriptor
1.799 +// or 0 if it is not a valid size for a shared memory file
1.800 +//
1.801 +static size_t sharedmem_filesize(int fd, TRAPS) {
1.802 +
1.803 + struct stat statbuf;
1.804 + int result;
1.805 +
1.806 + RESTARTABLE(::fstat(fd, &statbuf), result);
1.807 + if (result == OS_ERR) {
1.808 + if (PrintMiscellaneous && Verbose) {
1.809 + warning("fstat failed: %s\n", strerror(errno));
1.810 + }
1.811 + THROW_MSG_0(vmSymbols::java_io_IOException(),
1.812 + "Could not determine PerfMemory size");
1.813 + }
1.814 +
1.815 + if ((statbuf.st_size == 0) ||
1.816 + ((size_t)statbuf.st_size % os::vm_page_size() != 0)) {
1.817 + THROW_MSG_0(vmSymbols::java_lang_Exception(),
1.818 + "Invalid PerfMemory size");
1.819 + }
1.820 +
1.821 + return (size_t)statbuf.st_size;
1.822 +}
1.823 +
1.824 +// attach to a named shared memory region.
1.825 +//
1.826 +static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemoryMode mode, char** addr, size_t* sizep, TRAPS) {
1.827 +
1.828 + char* mapAddress;
1.829 + int result;
1.830 + int fd;
1.831 + size_t size = 0;
1.832 + const char* luser = NULL;
1.833 +
1.834 + int mmap_prot;
1.835 + int file_flags;
1.836 +
1.837 + ResourceMark rm;
1.838 +
1.839 + // map the high level access mode to the appropriate permission
1.840 + // constructs for the file and the shared memory mapping.
1.841 + if (mode == PerfMemory::PERF_MODE_RO) {
1.842 + mmap_prot = PROT_READ;
1.843 + file_flags = O_RDONLY;
1.844 + }
1.845 + else if (mode == PerfMemory::PERF_MODE_RW) {
1.846 +#ifdef LATER
1.847 + mmap_prot = PROT_READ | PROT_WRITE;
1.848 + file_flags = O_RDWR;
1.849 +#else
1.850 + THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1.851 + "Unsupported access mode");
1.852 +#endif
1.853 + }
1.854 + else {
1.855 + THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1.856 + "Illegal access mode");
1.857 + }
1.858 +
1.859 + if (user == NULL || strlen(user) == 0) {
1.860 + luser = get_user_name(vmid, CHECK);
1.861 + }
1.862 + else {
1.863 + luser = user;
1.864 + }
1.865 +
1.866 + if (luser == NULL) {
1.867 + THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1.868 + "Could not map vmid to user Name");
1.869 + }
1.870 +
1.871 + char* dirname = get_user_tmp_dir(luser);
1.872 +
1.873 + // since we don't follow symbolic links when creating the backing
1.874 + // store file, we don't follow them when attaching either.
1.875 + //
1.876 + if (!is_directory_secure(dirname)) {
1.877 + FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
1.878 + THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
1.879 + "Process not found");
1.880 + }
1.881 +
1.882 + char* filename = get_sharedmem_filename(dirname, vmid);
1.883 +
1.884 + // copy heap memory to resource memory. the open_sharedmem_file
1.885 + // method below need to use the filename, but could throw an
1.886 + // exception. using a resource array prevents the leak that
1.887 + // would otherwise occur.
1.888 + char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
1.889 + strcpy(rfilename, filename);
1.890 +
1.891 + // free the c heap resources that are no longer needed
1.892 + if (luser != user) FREE_C_HEAP_ARRAY(char, luser, mtInternal);
1.893 + FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
1.894 + FREE_C_HEAP_ARRAY(char, filename, mtInternal);
1.895 +
1.896 + // open the shared memory file for the give vmid
1.897 + fd = open_sharedmem_file(rfilename, file_flags, CHECK);
1.898 + assert(fd != OS_ERR, "unexpected value");
1.899 +
1.900 + if (*sizep == 0) {
1.901 + size = sharedmem_filesize(fd, CHECK);
1.902 + } else {
1.903 + size = *sizep;
1.904 + }
1.905 +
1.906 + assert(size > 0, "unexpected size <= 0");
1.907 +
1.908 + mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0);
1.909 +
1.910 + // attempt to close the file - restart if it gets interrupted,
1.911 + // but ignore other failures
1.912 + result = ::close(fd);
1.913 + assert(result != OS_ERR, "could not close file");
1.914 +
1.915 + if (mapAddress == MAP_FAILED) {
1.916 + if (PrintMiscellaneous && Verbose) {
1.917 + warning("mmap failed: %s\n", strerror(errno));
1.918 + }
1.919 + THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
1.920 + "Could not map PerfMemory");
1.921 + }
1.922 +
1.923 + // it does not go through os api, the operation has to record from here
1.924 + MemTracker::record_virtual_memory_reserve((address)mapAddress, size, mtInternal, CURRENT_PC);
1.925 +
1.926 + *addr = mapAddress;
1.927 + *sizep = size;
1.928 +
1.929 + if (PerfTraceMemOps) {
1.930 + tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at "
1.931 + INTPTR_FORMAT "\n", size, vmid, p2i((void*)mapAddress));
1.932 + }
1.933 +}
1.934 +
1.935 +
1.936 +
1.937 +
1.938 +// create the PerfData memory region
1.939 +//
1.940 +// This method creates the memory region used to store performance
1.941 +// data for the JVM. The memory may be created in standard or
1.942 +// shared memory.
1.943 +//
1.944 +void PerfMemory::create_memory_region(size_t size) {
1.945 +
1.946 + if (PerfDisableSharedMem) {
1.947 + // do not share the memory for the performance data.
1.948 + _start = create_standard_memory(size);
1.949 + }
1.950 + else {
1.951 + _start = create_shared_memory(size);
1.952 + if (_start == NULL) {
1.953 +
1.954 + // creation of the shared memory region failed, attempt
1.955 + // to create a contiguous, non-shared memory region instead.
1.956 + //
1.957 + if (PrintMiscellaneous && Verbose) {
1.958 + warning("Reverting to non-shared PerfMemory region.\n");
1.959 + }
1.960 + PerfDisableSharedMem = true;
1.961 + _start = create_standard_memory(size);
1.962 + }
1.963 + }
1.964 +
1.965 + if (_start != NULL) _capacity = size;
1.966 +
1.967 +}
1.968 +
1.969 +// delete the PerfData memory region
1.970 +//
1.971 +// This method deletes the memory region used to store performance
1.972 +// data for the JVM. The memory region indicated by the <address, size>
1.973 +// tuple will be inaccessible after a call to this method.
1.974 +//
1.975 +void PerfMemory::delete_memory_region() {
1.976 +
1.977 + assert((start() != NULL && capacity() > 0), "verify proper state");
1.978 +
1.979 + // If user specifies PerfDataSaveFile, it will save the performance data
1.980 + // to the specified file name no matter whether PerfDataSaveToFile is specified
1.981 + // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
1.982 + // -XX:+PerfDataSaveToFile.
1.983 + if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
1.984 + save_memory_to_file(start(), capacity());
1.985 + }
1.986 +
1.987 + if (PerfDisableSharedMem) {
1.988 + delete_standard_memory(start(), capacity());
1.989 + }
1.990 + else {
1.991 + delete_shared_memory(start(), capacity());
1.992 + }
1.993 +}
1.994 +
1.995 +// attach to the PerfData memory region for another JVM
1.996 +//
1.997 +// This method returns an <address, size> tuple that points to
1.998 +// a memory buffer that is kept reasonably synchronized with
1.999 +// the PerfData memory region for the indicated JVM. This
1.1000 +// buffer may be kept in synchronization via shared memory
1.1001 +// or some other mechanism that keeps the buffer updated.
1.1002 +//
1.1003 +// If the JVM chooses not to support the attachability feature,
1.1004 +// this method should throw an UnsupportedOperation exception.
1.1005 +//
1.1006 +// This implementation utilizes named shared memory to map
1.1007 +// the indicated process's PerfData memory region into this JVMs
1.1008 +// address space.
1.1009 +//
1.1010 +void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, char** addrp, size_t* sizep, TRAPS) {
1.1011 +
1.1012 + if (vmid == 0 || vmid == os::current_process_id()) {
1.1013 + *addrp = start();
1.1014 + *sizep = capacity();
1.1015 + return;
1.1016 + }
1.1017 +
1.1018 + mmap_attach_shared(user, vmid, mode, addrp, sizep, CHECK);
1.1019 +}
1.1020 +
1.1021 +// detach from the PerfData memory region of another JVM
1.1022 +//
1.1023 +// This method detaches the PerfData memory region of another
1.1024 +// JVM, specified as an <address, size> tuple of a buffer
1.1025 +// in this process's address space. This method may perform
1.1026 +// arbitrary actions to accomplish the detachment. The memory
1.1027 +// region specified by <address, size> will be inaccessible after
1.1028 +// a call to this method.
1.1029 +//
1.1030 +// If the JVM chooses not to support the attachability feature,
1.1031 +// this method should throw an UnsupportedOperation exception.
1.1032 +//
1.1033 +// This implementation utilizes named shared memory to detach
1.1034 +// the indicated process's PerfData memory region from this
1.1035 +// process's address space.
1.1036 +//
1.1037 +void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
1.1038 +
1.1039 + assert(addr != 0, "address sanity check");
1.1040 + assert(bytes > 0, "capacity sanity check");
1.1041 +
1.1042 + if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
1.1043 + // prevent accidental detachment of this process's PerfMemory region
1.1044 + return;
1.1045 + }
1.1046 +
1.1047 + unmap_shared(addr, bytes);
1.1048 +}
1.1049 +
1.1050 +char* PerfMemory::backing_store_filename() {
1.1051 + return backing_store_file_name;
1.1052 +}
