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src/os/bsd/vm/perfMemory_bsd.cpp@d2a62e0f25eb (annotated)

src/os/bsd/vm/perfMemory_bsd.cpp

Thu, 28 Jun 2012 17:03:16 -0400

author

zgu

date

Thu, 28 Jun 2012 17:03:16 -0400

changeset 3900

d2a62e0f25eb

parent 3156

f08d439fab8c

child 4153

b9a9ed0f8eeb

permissions

-rw-r--r--

6995781: Native Memory Tracking (Phase 1)
7151532: DCmd for hotspot native memory tracking
Summary: Implementation of native memory tracking phase 1, which tracks VM native memory usage, and related DCmd
Reviewed-by: acorn, coleenp, fparain

never@3156	1	/*
never@3156	2	* Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
never@3156	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
never@3156	4	*
never@3156	5	* This code is free software; you can redistribute it and/or modify it
never@3156	6	* under the terms of the GNU General Public License version 2 only, as
never@3156	7	* published by the Free Software Foundation.
never@3156	8	*
never@3156	9	* This code is distributed in the hope that it will be useful, but WITHOUT
never@3156	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
never@3156	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
never@3156	12	* version 2 for more details (a copy is included in the LICENSE file that
never@3156	13	* accompanied this code).
never@3156	14	*
never@3156	15	* You should have received a copy of the GNU General Public License version
never@3156	16	* 2 along with this work; if not, write to the Free Software Foundation,
never@3156	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
never@3156	18	*
never@3156	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
never@3156	20	* or visit www.oracle.com if you need additional information or have any
never@3156	21	* questions.
never@3156	22	*
never@3156	23	*/
never@3156	24
never@3156	25	#include "precompiled.hpp"
never@3156	26	#include "classfile/vmSymbols.hpp"
never@3156	27	#include "memory/allocation.inline.hpp"
never@3156	28	#include "memory/resourceArea.hpp"
never@3156	29	#include "oops/oop.inline.hpp"
never@3156	30	#include "os_bsd.inline.hpp"
never@3156	31	#include "runtime/handles.inline.hpp"
never@3156	32	#include "runtime/perfMemory.hpp"
never@3156	33	#include "utilities/exceptions.hpp"
never@3156	34
never@3156	35	// put OS-includes here
never@3156	36	# include <sys/types.h>
never@3156	37	# include <sys/mman.h>
never@3156	38	# include <errno.h>
never@3156	39	# include <stdio.h>
never@3156	40	# include <unistd.h>
never@3156	41	# include <sys/stat.h>
never@3156	42	# include <signal.h>
never@3156	43	# include <pwd.h>
never@3156	44
never@3156	45	static char* backing_store_file_name = NULL; // name of the backing store
never@3156	46	// file, if successfully created.
never@3156	47
never@3156	48	// Standard Memory Implementation Details
never@3156	49
never@3156	50	// create the PerfData memory region in standard memory.
never@3156	51	//
never@3156	52	static char* create_standard_memory(size_t size) {
never@3156	53
never@3156	54	// allocate an aligned chuck of memory
never@3156	55	char* mapAddress = os::reserve_memory(size);
never@3156	56
never@3156	57	if (mapAddress == NULL) {
never@3156	58	return NULL;
never@3156	59	}
never@3156	60
never@3156	61	// commit memory
never@3156	62	if (!os::commit_memory(mapAddress, size)) {
never@3156	63	if (PrintMiscellaneous && Verbose) {
never@3156	64	warning("Could not commit PerfData memory\n");
never@3156	65	}
never@3156	66	os::release_memory(mapAddress, size);
never@3156	67	return NULL;
never@3156	68	}
never@3156	69
never@3156	70	return mapAddress;
never@3156	71	}
never@3156	72
never@3156	73	// delete the PerfData memory region
never@3156	74	//
never@3156	75	static void delete_standard_memory(char* addr, size_t size) {
never@3156	76
never@3156	77	// there are no persistent external resources to cleanup for standard
never@3156	78	// memory. since DestroyJavaVM does not support unloading of the JVM,
never@3156	79	// cleanup of the memory resource is not performed. The memory will be
never@3156	80	// reclaimed by the OS upon termination of the process.
never@3156	81	//
never@3156	82	return;
never@3156	83	}
never@3156	84
never@3156	85	// save the specified memory region to the given file
never@3156	86	//
never@3156	87	// Note: this function might be called from signal handler (by os::abort()),
never@3156	88	// don't allocate heap memory.
never@3156	89	//
never@3156	90	static void save_memory_to_file(char* addr, size_t size) {
never@3156	91
never@3156	92	const char* destfile = PerfMemory::get_perfdata_file_path();
never@3156	93	assert(destfile[0] != '\0', "invalid PerfData file path");
never@3156	94
never@3156	95	int result;
never@3156	96
never@3156	97	RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE),
never@3156	98	result);;
never@3156	99	if (result == OS_ERR) {
never@3156	100	if (PrintMiscellaneous && Verbose) {
never@3156	101	warning("Could not create Perfdata save file: %s: %s\n",
never@3156	102	destfile, strerror(errno));
never@3156	103	}
never@3156	104	} else {
never@3156	105	int fd = result;
never@3156	106
never@3156	107	for (size_t remaining = size; remaining > 0;) {
never@3156	108
never@3156	109	RESTARTABLE(::write(fd, addr, remaining), result);
never@3156	110	if (result == OS_ERR) {
never@3156	111	if (PrintMiscellaneous && Verbose) {
never@3156	112	warning("Could not write Perfdata save file: %s: %s\n",
never@3156	113	destfile, strerror(errno));
never@3156	114	}
never@3156	115	break;
never@3156	116	}
never@3156	117
never@3156	118	remaining -= (size_t)result;
never@3156	119	addr += result;
never@3156	120	}
never@3156	121
never@3156	122	RESTARTABLE(::close(fd), result);
never@3156	123	if (PrintMiscellaneous && Verbose) {
never@3156	124	if (result == OS_ERR) {
never@3156	125	warning("Could not close %s: %s\n", destfile, strerror(errno));
never@3156	126	}
never@3156	127	}
never@3156	128	}
zgu@3900	129	FREE_C_HEAP_ARRAY(char, destfile, mtInternal);
never@3156	130	}
never@3156	131
never@3156	132
never@3156	133	// Shared Memory Implementation Details
never@3156	134
never@3156	135	// Note: the solaris and bsd shared memory implementation uses the mmap
never@3156	136	// interface with a backing store file to implement named shared memory.
never@3156	137	// Using the file system as the name space for shared memory allows a
never@3156	138	// common name space to be supported across a variety of platforms. It
never@3156	139	// also provides a name space that Java applications can deal with through
never@3156	140	// simple file apis.
never@3156	141	//
never@3156	142	// The solaris and bsd implementations store the backing store file in
never@3156	143	// a user specific temporary directory located in the /tmp file system,
never@3156	144	// which is always a local file system and is sometimes a RAM based file
never@3156	145	// system.
never@3156	146
never@3156	147	// return the user specific temporary directory name.
never@3156	148	//
never@3156	149	// the caller is expected to free the allocated memory.
never@3156	150	//
never@3156	151	static char* get_user_tmp_dir(const char* user) {
never@3156	152
never@3156	153	const char* tmpdir = os::get_temp_directory();
never@3156	154	const char* perfdir = PERFDATA_NAME;
never@3156	155	size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3;
zgu@3900	156	char* dirname = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
never@3156	157
never@3156	158	// construct the path name to user specific tmp directory
never@3156	159	snprintf(dirname, nbytes, "%s/%s_%s", tmpdir, perfdir, user);
never@3156	160
never@3156	161	return dirname;
never@3156	162	}
never@3156	163
never@3156	164	// convert the given file name into a process id. if the file
never@3156	165	// does not meet the file naming constraints, return 0.
never@3156	166	//
never@3156	167	static pid_t filename_to_pid(const char* filename) {
never@3156	168
never@3156	169	// a filename that doesn't begin with a digit is not a
never@3156	170	// candidate for conversion.
never@3156	171	//
never@3156	172	if (!isdigit(*filename)) {
never@3156	173	return 0;
never@3156	174	}
never@3156	175
never@3156	176	// check if file name can be converted to an integer without
never@3156	177	// any leftover characters.
never@3156	178	//
never@3156	179	char* remainder = NULL;
never@3156	180	errno = 0;
never@3156	181	pid_t pid = (pid_t)strtol(filename, &remainder, 10);
never@3156	182
never@3156	183	if (errno != 0) {
never@3156	184	return 0;
never@3156	185	}
never@3156	186
never@3156	187	// check for left over characters. If any, then the filename is
never@3156	188	// not a candidate for conversion.
never@3156	189	//
never@3156	190	if (remainder != NULL && *remainder != '\0') {
never@3156	191	return 0;
never@3156	192	}
never@3156	193
never@3156	194	// successful conversion, return the pid
never@3156	195	return pid;
never@3156	196	}
never@3156	197
never@3156	198
never@3156	199	// check if the given path is considered a secure directory for
never@3156	200	// the backing store files. Returns true if the directory exists
never@3156	201	// and is considered a secure location. Returns false if the path
never@3156	202	// is a symbolic link or if an error occurred.
never@3156	203	//
never@3156	204	static bool is_directory_secure(const char* path) {
never@3156	205	struct stat statbuf;
never@3156	206	int result = 0;
never@3156	207
never@3156	208	RESTARTABLE(::lstat(path, &statbuf), result);
never@3156	209	if (result == OS_ERR) {
never@3156	210	return false;
never@3156	211	}
never@3156	212
never@3156	213	// the path exists, now check it's mode
never@3156	214	if (S_ISLNK(statbuf.st_mode) || !S_ISDIR(statbuf.st_mode)) {
never@3156	215	// the path represents a link or some non-directory file type,
never@3156	216	// which is not what we expected. declare it insecure.
never@3156	217	//
never@3156	218	return false;
never@3156	219	}
never@3156	220	else {
never@3156	221	// we have an existing directory, check if the permissions are safe.
never@3156	222	//
never@3156	223	if ((statbuf.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
never@3156	224	// the directory is open for writing and could be subjected
never@3156	225	// to a symlnk attack. declare it insecure.
never@3156	226	//
never@3156	227	return false;
never@3156	228	}
never@3156	229	}
never@3156	230	return true;
never@3156	231	}
never@3156	232
never@3156	233
never@3156	234	// return the user name for the given user id
never@3156	235	//
never@3156	236	// the caller is expected to free the allocated memory.
never@3156	237	//
never@3156	238	static char* get_user_name(uid_t uid) {
never@3156	239
never@3156	240	struct passwd pwent;
never@3156	241
never@3156	242	// determine the max pwbuf size from sysconf, and hardcode
never@3156	243	// a default if this not available through sysconf.
never@3156	244	//
never@3156	245	long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
never@3156	246	if (bufsize == -1)
never@3156	247	bufsize = 1024;
never@3156	248
zgu@3900	249	char* pwbuf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
never@3156	250
never@3156	251	// POSIX interface to getpwuid_r is used on LINUX
never@3156	252	struct passwd* p;
never@3156	253	int result = getpwuid_r(uid, &pwent, pwbuf, (size_t)bufsize, &p);
never@3156	254
never@3156	255	if (result != 0 || p == NULL || p->pw_name == NULL || *(p->pw_name) == '\0') {
never@3156	256	if (PrintMiscellaneous && Verbose) {
never@3156	257	if (result != 0) {
never@3156	258	warning("Could not retrieve passwd entry: %s\n",
never@3156	259	strerror(result));
never@3156	260	}
never@3156	261	else if (p == NULL) {
never@3156	262	// this check is added to protect against an observed problem
never@3156	263	// with getpwuid_r() on RedHat 9 where getpwuid_r returns 0,
never@3156	264	// indicating success, but has p == NULL. This was observed when
never@3156	265	// inserting a file descriptor exhaustion fault prior to the call
never@3156	266	// getpwuid_r() call. In this case, error is set to the appropriate
never@3156	267	// error condition, but this is undocumented behavior. This check
never@3156	268	// is safe under any condition, but the use of errno in the output
never@3156	269	// message may result in an erroneous message.
never@3156	270	// Bug Id 89052 was opened with RedHat.
never@3156	271	//
never@3156	272	warning("Could not retrieve passwd entry: %s\n",
never@3156	273	strerror(errno));
never@3156	274	}
never@3156	275	else {
never@3156	276	warning("Could not determine user name: %s\n",
never@3156	277	p->pw_name == NULL ? "pw_name = NULL" :
never@3156	278	"pw_name zero length");
never@3156	279	}
never@3156	280	}
zgu@3900	281	FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal);
never@3156	282	return NULL;
never@3156	283	}
never@3156	284
zgu@3900	285	char* user_name = NEW_C_HEAP_ARRAY(char, strlen(p->pw_name) + 1, mtInternal);
never@3156	286	strcpy(user_name, p->pw_name);
never@3156	287
zgu@3900	288	FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal);
never@3156	289	return user_name;
never@3156	290	}
never@3156	291
never@3156	292	// return the name of the user that owns the process identified by vmid.
never@3156	293	//
never@3156	294	// This method uses a slow directory search algorithm to find the backing
never@3156	295	// store file for the specified vmid and returns the user name, as determined
never@3156	296	// by the user name suffix of the hsperfdata_<username> directory name.
never@3156	297	//
never@3156	298	// the caller is expected to free the allocated memory.
never@3156	299	//
never@3156	300	static char* get_user_name_slow(int vmid, TRAPS) {
never@3156	301
never@3156	302	// short circuit the directory search if the process doesn't even exist.
never@3156	303	if (kill(vmid, 0) == OS_ERR) {
never@3156	304	if (errno == ESRCH) {
never@3156	305	THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
never@3156	306	"Process not found");
never@3156	307	}
never@3156	308	else /* EPERM */ {
never@3156	309	THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
never@3156	310	}
never@3156	311	}
never@3156	312
never@3156	313	// directory search
never@3156	314	char* oldest_user = NULL;
never@3156	315	time_t oldest_ctime = 0;
never@3156	316
never@3156	317	const char* tmpdirname = os::get_temp_directory();
never@3156	318
never@3156	319	DIR* tmpdirp = os::opendir(tmpdirname);
never@3156	320
never@3156	321	if (tmpdirp == NULL) {
never@3156	322	return NULL;
never@3156	323	}
never@3156	324
never@3156	325	// for each entry in the directory that matches the pattern hsperfdata_*,
never@3156	326	// open the directory and check if the file for the given vmid exists.
never@3156	327	// The file with the expected name and the latest creation date is used
never@3156	328	// to determine the user name for the process id.
never@3156	329	//
never@3156	330	struct dirent* dentry;
zgu@3900	331	char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname), mtInternal);
never@3156	332	errno = 0;
never@3156	333	while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) {
never@3156	334
never@3156	335	// check if the directory entry is a hsperfdata file
never@3156	336	if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
never@3156	337	continue;
never@3156	338	}
never@3156	339
never@3156	340	char* usrdir_name = NEW_C_HEAP_ARRAY(char,
zgu@3900	341	strlen(tmpdirname) + strlen(dentry->d_name) + 2, mtInternal);
never@3156	342	strcpy(usrdir_name, tmpdirname);
never@3156	343	strcat(usrdir_name, "/");
never@3156	344	strcat(usrdir_name, dentry->d_name);
never@3156	345
never@3156	346	DIR* subdirp = os::opendir(usrdir_name);
never@3156	347
never@3156	348	if (subdirp == NULL) {
zgu@3900	349	FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
never@3156	350	continue;
never@3156	351	}
never@3156	352
never@3156	353	// Since we don't create the backing store files in directories
never@3156	354	// pointed to by symbolic links, we also don't follow them when
never@3156	355	// looking for the files. We check for a symbolic link after the
never@3156	356	// call to opendir in order to eliminate a small window where the
never@3156	357	// symlink can be exploited.
never@3156	358	//
never@3156	359	if (!is_directory_secure(usrdir_name)) {
zgu@3900	360	FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
never@3156	361	os::closedir(subdirp);
never@3156	362	continue;
never@3156	363	}
never@3156	364
never@3156	365	struct dirent* udentry;
zgu@3900	366	char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name), mtInternal);
never@3156	367	errno = 0;
never@3156	368	while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
never@3156	369
never@3156	370	if (filename_to_pid(udentry->d_name) == vmid) {
never@3156	371	struct stat statbuf;
never@3156	372	int result;
never@3156	373
never@3156	374	char* filename = NEW_C_HEAP_ARRAY(char,
zgu@3900	375	strlen(usrdir_name) + strlen(udentry->d_name) + 2, mtInternal);
never@3156	376
never@3156	377	strcpy(filename, usrdir_name);
never@3156	378	strcat(filename, "/");
never@3156	379	strcat(filename, udentry->d_name);
never@3156	380
never@3156	381	// don't follow symbolic links for the file
never@3156	382	RESTARTABLE(::lstat(filename, &statbuf), result);
never@3156	383	if (result == OS_ERR) {
zgu@3900	384	FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156	385	continue;
never@3156	386	}
never@3156	387
never@3156	388	// skip over files that are not regular files.
never@3156	389	if (!S_ISREG(statbuf.st_mode)) {
zgu@3900	390	FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156	391	continue;
never@3156	392	}
never@3156	393
never@3156	394	// compare and save filename with latest creation time
never@3156	395	if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) {
never@3156	396
never@3156	397	if (statbuf.st_ctime > oldest_ctime) {
never@3156	398	char* user = strchr(dentry->d_name, '_') + 1;
never@3156	399
zgu@3900	400	if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user, mtInternal);
zgu@3900	401	oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
never@3156	402
never@3156	403	strcpy(oldest_user, user);
never@3156	404	oldest_ctime = statbuf.st_ctime;
never@3156	405	}
never@3156	406	}
never@3156	407
zgu@3900	408	FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156	409	}
never@3156	410	}
never@3156	411	os::closedir(subdirp);
zgu@3900	412	FREE_C_HEAP_ARRAY(char, udbuf, mtInternal);
zgu@3900	413	FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
never@3156	414	}
never@3156	415	os::closedir(tmpdirp);
zgu@3900	416	FREE_C_HEAP_ARRAY(char, tdbuf, mtInternal);
never@3156	417
never@3156	418	return(oldest_user);
never@3156	419	}
never@3156	420
never@3156	421	// return the name of the user that owns the JVM indicated by the given vmid.
never@3156	422	//
never@3156	423	static char* get_user_name(int vmid, TRAPS) {
never@3156	424	return get_user_name_slow(vmid, CHECK_NULL);
never@3156	425	}
never@3156	426
never@3156	427	// return the file name of the backing store file for the named
never@3156	428	// shared memory region for the given user name and vmid.
never@3156	429	//
never@3156	430	// the caller is expected to free the allocated memory.
never@3156	431	//
never@3156	432	static char* get_sharedmem_filename(const char* dirname, int vmid) {
never@3156	433
never@3156	434	// add 2 for the file separator and a null terminator.
never@3156	435	size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
never@3156	436
zgu@3900	437	char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
never@3156	438	snprintf(name, nbytes, "%s/%d", dirname, vmid);
never@3156	439
never@3156	440	return name;
never@3156	441	}
never@3156	442
never@3156	443
never@3156	444	// remove file
never@3156	445	//
never@3156	446	// this method removes the file specified by the given path
never@3156	447	//
never@3156	448	static void remove_file(const char* path) {
never@3156	449
never@3156	450	int result;
never@3156	451
never@3156	452	// if the file is a directory, the following unlink will fail. since
never@3156	453	// we don't expect to find directories in the user temp directory, we
never@3156	454	// won't try to handle this situation. even if accidentially or
never@3156	455	// maliciously planted, the directory's presence won't hurt anything.
never@3156	456	//
never@3156	457	RESTARTABLE(::unlink(path), result);
never@3156	458	if (PrintMiscellaneous && Verbose && result == OS_ERR) {
never@3156	459	if (errno != ENOENT) {
never@3156	460	warning("Could not unlink shared memory backing"
never@3156	461	" store file %s : %s\n", path, strerror(errno));
never@3156	462	}
never@3156	463	}
never@3156	464	}
never@3156	465
never@3156	466
never@3156	467	// remove file
never@3156	468	//
never@3156	469	// this method removes the file with the given file name in the
never@3156	470	// named directory.
never@3156	471	//
never@3156	472	static void remove_file(const char* dirname, const char* filename) {
never@3156	473
never@3156	474	size_t nbytes = strlen(dirname) + strlen(filename) + 2;
zgu@3900	475	char* path = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
never@3156	476
never@3156	477	strcpy(path, dirname);
never@3156	478	strcat(path, "/");
never@3156	479	strcat(path, filename);
never@3156	480
never@3156	481	remove_file(path);
never@3156	482
zgu@3900	483	FREE_C_HEAP_ARRAY(char, path, mtInternal);
never@3156	484	}
never@3156	485
never@3156	486
never@3156	487	// cleanup stale shared memory resources
never@3156	488	//
never@3156	489	// This method attempts to remove all stale shared memory files in
never@3156	490	// the named user temporary directory. It scans the named directory
never@3156	491	// for files matching the pattern ^$[0-9]*$. For each file found, the
never@3156	492	// process id is extracted from the file name and a test is run to
never@3156	493	// determine if the process is alive. If the process is not alive,
never@3156	494	// any stale file resources are removed.
never@3156	495	//
never@3156	496	static void cleanup_sharedmem_resources(const char* dirname) {
never@3156	497
never@3156	498	// open the user temp directory
never@3156	499	DIR* dirp = os::opendir(dirname);
never@3156	500
never@3156	501	if (dirp == NULL) {
never@3156	502	// directory doesn't exist, so there is nothing to cleanup
never@3156	503	return;
never@3156	504	}
never@3156	505
never@3156	506	if (!is_directory_secure(dirname)) {
never@3156	507	// the directory is not a secure directory
never@3156	508	return;
never@3156	509	}
never@3156	510
never@3156	511	// for each entry in the directory that matches the expected file
never@3156	512	// name pattern, determine if the file resources are stale and if
never@3156	513	// so, remove the file resources. Note, instrumented HotSpot processes
never@3156	514	// for this user may start and/or terminate during this search and
never@3156	515	// remove or create new files in this directory. The behavior of this
never@3156	516	// loop under these conditions is dependent upon the implementation of
never@3156	517	// opendir/readdir.
never@3156	518	//
never@3156	519	struct dirent* entry;
zgu@3900	520	char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname), mtInternal);
never@3156	521	errno = 0;
never@3156	522	while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) {
never@3156	523
never@3156	524	pid_t pid = filename_to_pid(entry->d_name);
never@3156	525
never@3156	526	if (pid == 0) {
never@3156	527
never@3156	528	if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
never@3156	529
never@3156	530	// attempt to remove all unexpected files, except "." and ".."
never@3156	531	remove_file(dirname, entry->d_name);
never@3156	532	}
never@3156	533
never@3156	534	errno = 0;
never@3156	535	continue;
never@3156	536	}
never@3156	537
never@3156	538	// we now have a file name that converts to a valid integer
never@3156	539	// that could represent a process id . if this process id
never@3156	540	// matches the current process id or the process is not running,
never@3156	541	// then remove the stale file resources.
never@3156	542	//
never@3156	543	// process liveness is detected by sending signal number 0 to
never@3156	544	// the process id (see kill(2)). if kill determines that the
never@3156	545	// process does not exist, then the file resources are removed.
never@3156	546	// if kill determines that that we don't have permission to
never@3156	547	// signal the process, then the file resources are assumed to
never@3156	548	// be stale and are removed because the resources for such a
never@3156	549	// process should be in a different user specific directory.
never@3156	550	//
never@3156	551	if ((pid == os::current_process_id()) ||
never@3156	552	(kill(pid, 0) == OS_ERR && (errno == ESRCH || errno == EPERM))) {
never@3156	553
never@3156	554	remove_file(dirname, entry->d_name);
never@3156	555	}
never@3156	556	errno = 0;
never@3156	557	}
never@3156	558	os::closedir(dirp);
zgu@3900	559	FREE_C_HEAP_ARRAY(char, dbuf, mtInternal);
never@3156	560	}
never@3156	561
never@3156	562	// make the user specific temporary directory. Returns true if
never@3156	563	// the directory exists and is secure upon return. Returns false
never@3156	564	// if the directory exists but is either a symlink, is otherwise
never@3156	565	// insecure, or if an error occurred.
never@3156	566	//
never@3156	567	static bool make_user_tmp_dir(const char* dirname) {
never@3156	568
never@3156	569	// create the directory with 0755 permissions. note that the directory
never@3156	570	// will be owned by euid::egid, which may not be the same as uid::gid.
never@3156	571	//
never@3156	572	if (mkdir(dirname, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) == OS_ERR) {
never@3156	573	if (errno == EEXIST) {
never@3156	574	// The directory already exists and was probably created by another
never@3156	575	// JVM instance. However, this could also be the result of a
never@3156	576	// deliberate symlink. Verify that the existing directory is safe.
never@3156	577	//
never@3156	578	if (!is_directory_secure(dirname)) {
never@3156	579	// directory is not secure
never@3156	580	if (PrintMiscellaneous && Verbose) {
never@3156	581	warning("%s directory is insecure\n", dirname);
never@3156	582	}
never@3156	583	return false;
never@3156	584	}
never@3156	585	}
never@3156	586	else {
never@3156	587	// we encountered some other failure while attempting
never@3156	588	// to create the directory
never@3156	589	//
never@3156	590	if (PrintMiscellaneous && Verbose) {
never@3156	591	warning("could not create directory %s: %s\n",
never@3156	592	dirname, strerror(errno));
never@3156	593	}
never@3156	594	return false;
never@3156	595	}
never@3156	596	}
never@3156	597	return true;
never@3156	598	}
never@3156	599
never@3156	600	// create the shared memory file resources
never@3156	601	//
never@3156	602	// This method creates the shared memory file with the given size
never@3156	603	// This method also creates the user specific temporary directory, if
never@3156	604	// it does not yet exist.
never@3156	605	//
never@3156	606	static int create_sharedmem_resources(const char* dirname, const char* filename, size_t size) {
never@3156	607
never@3156	608	// make the user temporary directory
never@3156	609	if (!make_user_tmp_dir(dirname)) {
never@3156	610	// could not make/find the directory or the found directory
never@3156	611	// was not secure
never@3156	612	return -1;
never@3156	613	}
never@3156	614
never@3156	615	int result;
never@3156	616
never@3156	617	RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_TRUNC, S_IREAD|S_IWRITE), result);
never@3156	618	if (result == OS_ERR) {
never@3156	619	if (PrintMiscellaneous && Verbose) {
never@3156	620	warning("could not create file %s: %s\n", filename, strerror(errno));
never@3156	621	}
never@3156	622	return -1;
never@3156	623	}
never@3156	624
never@3156	625	// save the file descriptor
never@3156	626	int fd = result;
never@3156	627
never@3156	628	// set the file size
never@3156	629	RESTARTABLE(::ftruncate(fd, (off_t)size), result);
never@3156	630	if (result == OS_ERR) {
never@3156	631	if (PrintMiscellaneous && Verbose) {
never@3156	632	warning("could not set shared memory file size: %s\n", strerror(errno));
never@3156	633	}
never@3156	634	RESTARTABLE(::close(fd), result);
never@3156	635	return -1;
never@3156	636	}
never@3156	637
never@3156	638	// Verify that we have enough disk space for this file.
never@3156	639	// We'll get random SIGBUS crashes on memory accesses if
never@3156	640	// we don't.
never@3156	641
never@3156	642	for (size_t seekpos = 0; seekpos < size; seekpos += os::vm_page_size()) {
never@3156	643	int zero_int = 0;
never@3156	644	result = (int)os::seek_to_file_offset(fd, (jlong)(seekpos));
never@3156	645	if (result == -1 ) break;
never@3156	646	RESTARTABLE(::write(fd, &zero_int, 1), result);
never@3156	647	if (result != 1) {
never@3156	648	if (errno == ENOSPC) {
never@3156	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);
never@3156	650	}
never@3156	651	break;
never@3156	652	}
never@3156	653	}
never@3156	654
never@3156	655	if (result != -1) {
never@3156	656	return fd;
never@3156	657	} else {
never@3156	658	RESTARTABLE(::close(fd), result);
never@3156	659	return -1;
never@3156	660	}
never@3156	661	}
never@3156	662
never@3156	663	// open the shared memory file for the given user and vmid. returns
never@3156	664	// the file descriptor for the open file or -1 if the file could not
never@3156	665	// be opened.
never@3156	666	//
never@3156	667	static int open_sharedmem_file(const char* filename, int oflags, TRAPS) {
never@3156	668
never@3156	669	// open the file
never@3156	670	int result;
never@3156	671	RESTARTABLE(::open(filename, oflags), result);
never@3156	672	if (result == OS_ERR) {
never@3156	673	if (errno == ENOENT) {
never@3156	674	THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
never@3156	675	"Process not found");
never@3156	676	}
never@3156	677	else if (errno == EACCES) {
never@3156	678	THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
never@3156	679	"Permission denied");
never@3156	680	}
never@3156	681	else {
never@3156	682	THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
never@3156	683	}
never@3156	684	}
never@3156	685
never@3156	686	return result;
never@3156	687	}
never@3156	688
never@3156	689	// create a named shared memory region. returns the address of the
never@3156	690	// memory region on success or NULL on failure. A return value of
never@3156	691	// NULL will ultimately disable the shared memory feature.
never@3156	692	//
never@3156	693	// On Solaris and Bsd, the name space for shared memory objects
never@3156	694	// is the file system name space.
never@3156	695	//
never@3156	696	// A monitoring application attaching to a JVM does not need to know
never@3156	697	// the file system name of the shared memory object. However, it may
never@3156	698	// be convenient for applications to discover the existence of newly
never@3156	699	// created and terminating JVMs by watching the file system name space
never@3156	700	// for files being created or removed.
never@3156	701	//
never@3156	702	static char* mmap_create_shared(size_t size) {
never@3156	703
never@3156	704	int result;
never@3156	705	int fd;
never@3156	706	char* mapAddress;
never@3156	707
never@3156	708	int vmid = os::current_process_id();
never@3156	709
never@3156	710	char* user_name = get_user_name(geteuid());
never@3156	711
never@3156	712	if (user_name == NULL)
never@3156	713	return NULL;
never@3156	714
never@3156	715	char* dirname = get_user_tmp_dir(user_name);
never@3156	716	char* filename = get_sharedmem_filename(dirname, vmid);
never@3156	717
never@3156	718	// cleanup any stale shared memory files
never@3156	719	cleanup_sharedmem_resources(dirname);
never@3156	720
never@3156	721	assert(((size > 0) && (size % os::vm_page_size() == 0)),
never@3156	722	"unexpected PerfMemory region size");
never@3156	723
never@3156	724	fd = create_sharedmem_resources(dirname, filename, size);
never@3156	725
zgu@3900	726	FREE_C_HEAP_ARRAY(char, user_name, mtInternal);
zgu@3900	727	FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
never@3156	728
never@3156	729	if (fd == -1) {
zgu@3900	730	FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156	731	return NULL;
never@3156	732	}
never@3156	733
never@3156	734	mapAddress = (char*)::mmap((char*)0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
never@3156	735
never@3156	736	// attempt to close the file - restart it if it was interrupted,
never@3156	737	// but ignore other failures
never@3156	738	RESTARTABLE(::close(fd), result);
never@3156	739	assert(result != OS_ERR, "could not close file");
never@3156	740
never@3156	741	if (mapAddress == MAP_FAILED) {
never@3156	742	if (PrintMiscellaneous && Verbose) {
never@3156	743	warning("mmap failed - %s\n", strerror(errno));
never@3156	744	}
never@3156	745	remove_file(filename);
zgu@3900	746	FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156	747	return NULL;
never@3156	748	}
never@3156	749
never@3156	750	// save the file name for use in delete_shared_memory()
never@3156	751	backing_store_file_name = filename;
never@3156	752
never@3156	753	// clear the shared memory region
never@3156	754	(void)::memset((void*) mapAddress, 0, size);
never@3156	755
never@3156	756	return mapAddress;
never@3156	757	}
never@3156	758
never@3156	759	// release a named shared memory region
never@3156	760	//
never@3156	761	static void unmap_shared(char* addr, size_t bytes) {
never@3156	762	os::release_memory(addr, bytes);
never@3156	763	}
never@3156	764
never@3156	765	// create the PerfData memory region in shared memory.
never@3156	766	//
never@3156	767	static char* create_shared_memory(size_t size) {
never@3156	768
never@3156	769	// create the shared memory region.
never@3156	770	return mmap_create_shared(size);
never@3156	771	}
never@3156	772
never@3156	773	// delete the shared PerfData memory region
never@3156	774	//
never@3156	775	static void delete_shared_memory(char* addr, size_t size) {
never@3156	776
never@3156	777	// cleanup the persistent shared memory resources. since DestroyJavaVM does
never@3156	778	// not support unloading of the JVM, unmapping of the memory resource is
never@3156	779	// not performed. The memory will be reclaimed by the OS upon termination of
never@3156	780	// the process. The backing store file is deleted from the file system.
never@3156	781
never@3156	782	assert(!PerfDisableSharedMem, "shouldn't be here");
never@3156	783
never@3156	784	if (backing_store_file_name != NULL) {
never@3156	785	remove_file(backing_store_file_name);
never@3156	786	// Don't.. Free heap memory could deadlock os::abort() if it is called
never@3156	787	// from signal handler. OS will reclaim the heap memory.
never@3156	788	// FREE_C_HEAP_ARRAY(char, backing_store_file_name);
never@3156	789	backing_store_file_name = NULL;
never@3156	790	}
never@3156	791	}
never@3156	792
never@3156	793	// return the size of the file for the given file descriptor
never@3156	794	// or 0 if it is not a valid size for a shared memory file
never@3156	795	//
never@3156	796	static size_t sharedmem_filesize(int fd, TRAPS) {
never@3156	797
never@3156	798	struct stat statbuf;
never@3156	799	int result;
never@3156	800
never@3156	801	RESTARTABLE(::fstat(fd, &statbuf), result);
never@3156	802	if (result == OS_ERR) {
never@3156	803	if (PrintMiscellaneous && Verbose) {
never@3156	804	warning("fstat failed: %s\n", strerror(errno));
never@3156	805	}
never@3156	806	THROW_MSG_0(vmSymbols::java_io_IOException(),
never@3156	807	"Could not determine PerfMemory size");
never@3156	808	}
never@3156	809
never@3156	810	if ((statbuf.st_size == 0) ||
never@3156	811	((size_t)statbuf.st_size % os::vm_page_size() != 0)) {
never@3156	812	THROW_MSG_0(vmSymbols::java_lang_Exception(),
never@3156	813	"Invalid PerfMemory size");
never@3156	814	}
never@3156	815
never@3156	816	return (size_t)statbuf.st_size;
never@3156	817	}
never@3156	818
never@3156	819	// attach to a named shared memory region.
never@3156	820	//
never@3156	821	static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemoryMode mode, char** addr, size_t* sizep, TRAPS) {
never@3156	822
never@3156	823	char* mapAddress;
never@3156	824	int result;
never@3156	825	int fd;
never@3156	826	size_t size;
never@3156	827	const char* luser = NULL;
never@3156	828
never@3156	829	int mmap_prot;
never@3156	830	int file_flags;
never@3156	831
never@3156	832	ResourceMark rm;
never@3156	833
never@3156	834	// map the high level access mode to the appropriate permission
never@3156	835	// constructs for the file and the shared memory mapping.
never@3156	836	if (mode == PerfMemory::PERF_MODE_RO) {
never@3156	837	mmap_prot = PROT_READ;
never@3156	838	file_flags = O_RDONLY;
never@3156	839	}
never@3156	840	else if (mode == PerfMemory::PERF_MODE_RW) {
never@3156	841	#ifdef LATER
never@3156	842	mmap_prot = PROT_READ | PROT_WRITE;
never@3156	843	file_flags = O_RDWR;
never@3156	844	#else
never@3156	845	THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
never@3156	846	"Unsupported access mode");
never@3156	847	#endif
never@3156	848	}
never@3156	849	else {
never@3156	850	THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
never@3156	851	"Illegal access mode");
never@3156	852	}
never@3156	853
never@3156	854	if (user == NULL || strlen(user) == 0) {
never@3156	855	luser = get_user_name(vmid, CHECK);
never@3156	856	}
never@3156	857	else {
never@3156	858	luser = user;
never@3156	859	}
never@3156	860
never@3156	861	if (luser == NULL) {
never@3156	862	THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
never@3156	863	"Could not map vmid to user Name");
never@3156	864	}
never@3156	865
never@3156	866	char* dirname = get_user_tmp_dir(luser);
never@3156	867
never@3156	868	// since we don't follow symbolic links when creating the backing
never@3156	869	// store file, we don't follow them when attaching either.
never@3156	870	//
never@3156	871	if (!is_directory_secure(dirname)) {
zgu@3900	872	FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
never@3156	873	THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
never@3156	874	"Process not found");
never@3156	875	}
never@3156	876
never@3156	877	char* filename = get_sharedmem_filename(dirname, vmid);
never@3156	878
never@3156	879	// copy heap memory to resource memory. the open_sharedmem_file
never@3156	880	// method below need to use the filename, but could throw an
never@3156	881	// exception. using a resource array prevents the leak that
never@3156	882	// would otherwise occur.
never@3156	883	char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
never@3156	884	strcpy(rfilename, filename);
never@3156	885
never@3156	886	// free the c heap resources that are no longer needed
zgu@3900	887	if (luser != user) FREE_C_HEAP_ARRAY(char, luser, mtInternal);
zgu@3900	888	FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
zgu@3900	889	FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156	890
never@3156	891	// open the shared memory file for the give vmid
never@3156	892	fd = open_sharedmem_file(rfilename, file_flags, CHECK);
never@3156	893	assert(fd != OS_ERR, "unexpected value");
never@3156	894
never@3156	895	if (*sizep == 0) {
never@3156	896	size = sharedmem_filesize(fd, CHECK);
never@3156	897	assert(size != 0, "unexpected size");
never@3156	898	}
never@3156	899
never@3156	900	mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0);
never@3156	901
never@3156	902	// attempt to close the file - restart if it gets interrupted,
never@3156	903	// but ignore other failures
never@3156	904	RESTARTABLE(::close(fd), result);
never@3156	905	assert(result != OS_ERR, "could not close file");
never@3156	906
never@3156	907	if (mapAddress == MAP_FAILED) {
never@3156	908	if (PrintMiscellaneous && Verbose) {
never@3156	909	warning("mmap failed: %s\n", strerror(errno));
never@3156	910	}
never@3156	911	THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
never@3156	912	"Could not map PerfMemory");
never@3156	913	}
never@3156	914
never@3156	915	*addr = mapAddress;
never@3156	916	*sizep = size;
never@3156	917
never@3156	918	if (PerfTraceMemOps) {
never@3156	919	tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at "
never@3156	920	INTPTR_FORMAT "\n", size, vmid, (void*)mapAddress);
never@3156	921	}
never@3156	922	}
never@3156	923
never@3156	924
never@3156	925
never@3156	926
never@3156	927	// create the PerfData memory region
never@3156	928	//
never@3156	929	// This method creates the memory region used to store performance
never@3156	930	// data for the JVM. The memory may be created in standard or
never@3156	931	// shared memory.
never@3156	932	//
never@3156	933	void PerfMemory::create_memory_region(size_t size) {
never@3156	934
never@3156	935	if (PerfDisableSharedMem) {
never@3156	936	// do not share the memory for the performance data.
never@3156	937	_start = create_standard_memory(size);
never@3156	938	}
never@3156	939	else {
never@3156	940	_start = create_shared_memory(size);
never@3156	941	if (_start == NULL) {
never@3156	942
never@3156	943	// creation of the shared memory region failed, attempt
never@3156	944	// to create a contiguous, non-shared memory region instead.
never@3156	945	//
never@3156	946	if (PrintMiscellaneous && Verbose) {
never@3156	947	warning("Reverting to non-shared PerfMemory region.\n");
never@3156	948	}
never@3156	949	PerfDisableSharedMem = true;
never@3156	950	_start = create_standard_memory(size);
never@3156	951	}
never@3156	952	}
never@3156	953
never@3156	954	if (_start != NULL) _capacity = size;
never@3156	955
never@3156	956	}
never@3156	957
never@3156	958	// delete the PerfData memory region
never@3156	959	//
never@3156	960	// This method deletes the memory region used to store performance
never@3156	961	// data for the JVM. The memory region indicated by the <address, size>
never@3156	962	// tuple will be inaccessible after a call to this method.
never@3156	963	//
never@3156	964	void PerfMemory::delete_memory_region() {
never@3156	965
never@3156	966	assert((start() != NULL && capacity() > 0), "verify proper state");
never@3156	967
never@3156	968	// If user specifies PerfDataSaveFile, it will save the performance data
never@3156	969	// to the specified file name no matter whether PerfDataSaveToFile is specified
never@3156	970	// or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
never@3156	971	// -XX:+PerfDataSaveToFile.
never@3156	972	if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
never@3156	973	save_memory_to_file(start(), capacity());
never@3156	974	}
never@3156	975
never@3156	976	if (PerfDisableSharedMem) {
never@3156	977	delete_standard_memory(start(), capacity());
never@3156	978	}
never@3156	979	else {
never@3156	980	delete_shared_memory(start(), capacity());
never@3156	981	}
never@3156	982	}
never@3156	983
never@3156	984	// attach to the PerfData memory region for another JVM
never@3156	985	//
never@3156	986	// This method returns an <address, size> tuple that points to
never@3156	987	// a memory buffer that is kept reasonably synchronized with
never@3156	988	// the PerfData memory region for the indicated JVM. This
never@3156	989	// buffer may be kept in synchronization via shared memory
never@3156	990	// or some other mechanism that keeps the buffer updated.
never@3156	991	//
never@3156	992	// If the JVM chooses not to support the attachability feature,
never@3156	993	// this method should throw an UnsupportedOperation exception.
never@3156	994	//
never@3156	995	// This implementation utilizes named shared memory to map
never@3156	996	// the indicated process's PerfData memory region into this JVMs
never@3156	997	// address space.
never@3156	998	//
never@3156	999	void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, char** addrp, size_t* sizep, TRAPS) {
never@3156	1000
never@3156	1001	if (vmid == 0 || vmid == os::current_process_id()) {
never@3156	1002	*addrp = start();
never@3156	1003	*sizep = capacity();
never@3156	1004	return;
never@3156	1005	}
never@3156	1006
never@3156	1007	mmap_attach_shared(user, vmid, mode, addrp, sizep, CHECK);
never@3156	1008	}
never@3156	1009
never@3156	1010	// detach from the PerfData memory region of another JVM
never@3156	1011	//
never@3156	1012	// This method detaches the PerfData memory region of another
never@3156	1013	// JVM, specified as an <address, size> tuple of a buffer
never@3156	1014	// in this process's address space. This method may perform
never@3156	1015	// arbitrary actions to accomplish the detachment. The memory
never@3156	1016	// region specified by <address, size> will be inaccessible after
never@3156	1017	// a call to this method.
never@3156	1018	//
never@3156	1019	// If the JVM chooses not to support the attachability feature,
never@3156	1020	// this method should throw an UnsupportedOperation exception.
never@3156	1021	//
never@3156	1022	// This implementation utilizes named shared memory to detach
never@3156	1023	// the indicated process's PerfData memory region from this
never@3156	1024	// process's address space.
never@3156	1025	//
never@3156	1026	void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
never@3156	1027
never@3156	1028	assert(addr != 0, "address sanity check");
never@3156	1029	assert(bytes > 0, "capacity sanity check");
never@3156	1030
never@3156	1031	if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
never@3156	1032	// prevent accidental detachment of this process's PerfMemory region
never@3156	1033	return;
never@3156	1034	}
never@3156	1035
never@3156	1036	unmap_shared(addr, bytes);
never@3156	1037	}
never@3156	1038
never@3156	1039	char* PerfMemory::backing_store_filename() {
never@3156	1040	return backing_store_file_name;
never@3156	1041	}