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src/os/bsd/vm/perfMemory_bsd.cpp@833b0f92429a (annotated)

src/os/bsd/vm/perfMemory_bsd.cpp

Wed, 27 Aug 2014 08:19:12 -0400

author

zgu

date

Wed, 27 Aug 2014 08:19:12 -0400

changeset 7074

833b0f92429a

parent 6680

78bbf4d43a14

child 7495

42f27b59c550

child 7709

5ca2ea5eeff0

permissions

-rw-r--r--

8046598: Scalable Native memory tracking development
Summary: Enhance scalability of native memory tracking
Reviewed-by: coleenp, ctornqvi, gtriantafill

never@3156	1	/*
drchase@6680	2	* Copyright (c) 2001, 2014, 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"
zgu@4193	33	#include "services/memTracker.hpp"
never@3156	34	#include "utilities/exceptions.hpp"
never@3156	35
never@3156	36	// put OS-includes here
never@3156	37	# include <sys/types.h>
never@3156	38	# include <sys/mman.h>
never@3156	39	# include <errno.h>
never@3156	40	# include <stdio.h>
never@3156	41	# include <unistd.h>
never@3156	42	# include <sys/stat.h>
never@3156	43	# include <signal.h>
never@3156	44	# include <pwd.h>
never@3156	45
never@3156	46	static char* backing_store_file_name = NULL; // name of the backing store
never@3156	47	// file, if successfully created.
never@3156	48
never@3156	49	// Standard Memory Implementation Details
never@3156	50
never@3156	51	// create the PerfData memory region in standard memory.
never@3156	52	//
never@3156	53	static char* create_standard_memory(size_t size) {
never@3156	54
never@3156	55	// allocate an aligned chuck of memory
never@3156	56	char* mapAddress = os::reserve_memory(size);
never@3156	57
never@3156	58	if (mapAddress == NULL) {
never@3156	59	return NULL;
never@3156	60	}
never@3156	61
never@3156	62	// commit memory
dcubed@5255	63	if (!os::commit_memory(mapAddress, size, !ExecMem)) {
never@3156	64	if (PrintMiscellaneous && Verbose) {
never@3156	65	warning("Could not commit PerfData memory\n");
never@3156	66	}
never@3156	67	os::release_memory(mapAddress, size);
never@3156	68	return NULL;
never@3156	69	}
never@3156	70
never@3156	71	return mapAddress;
never@3156	72	}
never@3156	73
never@3156	74	// delete the PerfData memory region
never@3156	75	//
never@3156	76	static void delete_standard_memory(char* addr, size_t size) {
never@3156	77
never@3156	78	// there are no persistent external resources to cleanup for standard
never@3156	79	// memory. since DestroyJavaVM does not support unloading of the JVM,
never@3156	80	// cleanup of the memory resource is not performed. The memory will be
never@3156	81	// reclaimed by the OS upon termination of the process.
never@3156	82	//
never@3156	83	return;
never@3156	84	}
never@3156	85
never@3156	86	// save the specified memory region to the given file
never@3156	87	//
never@3156	88	// Note: this function might be called from signal handler (by os::abort()),
never@3156	89	// don't allocate heap memory.
never@3156	90	//
never@3156	91	static void save_memory_to_file(char* addr, size_t size) {
never@3156	92
never@3156	93	const char* destfile = PerfMemory::get_perfdata_file_path();
never@3156	94	assert(destfile[0] != '\0', "invalid PerfData file path");
never@3156	95
never@3156	96	int result;
never@3156	97
never@3156	98	RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE),
never@3156	99	result);;
never@3156	100	if (result == OS_ERR) {
never@3156	101	if (PrintMiscellaneous && Verbose) {
never@3156	102	warning("Could not create Perfdata save file: %s: %s\n",
never@3156	103	destfile, strerror(errno));
never@3156	104	}
never@3156	105	} else {
never@3156	106	int fd = result;
never@3156	107
never@3156	108	for (size_t remaining = size; remaining > 0;) {
never@3156	109
never@3156	110	RESTARTABLE(::write(fd, addr, remaining), result);
never@3156	111	if (result == OS_ERR) {
never@3156	112	if (PrintMiscellaneous && Verbose) {
never@3156	113	warning("Could not write Perfdata save file: %s: %s\n",
never@3156	114	destfile, strerror(errno));
never@3156	115	}
never@3156	116	break;
never@3156	117	}
never@3156	118
never@3156	119	remaining -= (size_t)result;
never@3156	120	addr += result;
never@3156	121	}
never@3156	122
rdurbin@5264	123	result = ::close(fd);
never@3156	124	if (PrintMiscellaneous && Verbose) {
never@3156	125	if (result == OS_ERR) {
never@3156	126	warning("Could not close %s: %s\n", destfile, strerror(errno));
never@3156	127	}
never@3156	128	}
never@3156	129	}
zgu@3900	130	FREE_C_HEAP_ARRAY(char, destfile, mtInternal);
never@3156	131	}
never@3156	132
never@3156	133
never@3156	134	// Shared Memory Implementation Details
never@3156	135
never@3156	136	// Note: the solaris and bsd shared memory implementation uses the mmap
never@3156	137	// interface with a backing store file to implement named shared memory.
never@3156	138	// Using the file system as the name space for shared memory allows a
never@3156	139	// common name space to be supported across a variety of platforms. It
never@3156	140	// also provides a name space that Java applications can deal with through
never@3156	141	// simple file apis.
never@3156	142	//
never@3156	143	// The solaris and bsd implementations store the backing store file in
never@3156	144	// a user specific temporary directory located in the /tmp file system,
never@3156	145	// which is always a local file system and is sometimes a RAM based file
never@3156	146	// system.
never@3156	147
never@3156	148	// return the user specific temporary directory name.
never@3156	149	//
never@3156	150	// the caller is expected to free the allocated memory.
never@3156	151	//
never@3156	152	static char* get_user_tmp_dir(const char* user) {
never@3156	153
never@3156	154	const char* tmpdir = os::get_temp_directory();
never@3156	155	const char* perfdir = PERFDATA_NAME;
never@3156	156	size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3;
zgu@3900	157	char* dirname = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
never@3156	158
never@3156	159	// construct the path name to user specific tmp directory
never@3156	160	snprintf(dirname, nbytes, "%s/%s_%s", tmpdir, perfdir, user);
never@3156	161
never@3156	162	return dirname;
never@3156	163	}
never@3156	164
never@3156	165	// convert the given file name into a process id. if the file
never@3156	166	// does not meet the file naming constraints, return 0.
never@3156	167	//
never@3156	168	static pid_t filename_to_pid(const char* filename) {
never@3156	169
never@3156	170	// a filename that doesn't begin with a digit is not a
never@3156	171	// candidate for conversion.
never@3156	172	//
never@3156	173	if (!isdigit(*filename)) {
never@3156	174	return 0;
never@3156	175	}
never@3156	176
never@3156	177	// check if file name can be converted to an integer without
never@3156	178	// any leftover characters.
never@3156	179	//
never@3156	180	char* remainder = NULL;
never@3156	181	errno = 0;
never@3156	182	pid_t pid = (pid_t)strtol(filename, &remainder, 10);
never@3156	183
never@3156	184	if (errno != 0) {
never@3156	185	return 0;
never@3156	186	}
never@3156	187
never@3156	188	// check for left over characters. If any, then the filename is
never@3156	189	// not a candidate for conversion.
never@3156	190	//
never@3156	191	if (remainder != NULL && *remainder != '\0') {
never@3156	192	return 0;
never@3156	193	}
never@3156	194
never@3156	195	// successful conversion, return the pid
never@3156	196	return pid;
never@3156	197	}
never@3156	198
never@3156	199
never@3156	200	// check if the given path is considered a secure directory for
never@3156	201	// the backing store files. Returns true if the directory exists
never@3156	202	// and is considered a secure location. Returns false if the path
never@3156	203	// is a symbolic link or if an error occurred.
never@3156	204	//
never@3156	205	static bool is_directory_secure(const char* path) {
never@3156	206	struct stat statbuf;
never@3156	207	int result = 0;
never@3156	208
never@3156	209	RESTARTABLE(::lstat(path, &statbuf), result);
never@3156	210	if (result == OS_ERR) {
never@3156	211	return false;
never@3156	212	}
never@3156	213
never@3156	214	// the path exists, now check it's mode
never@3156	215	if (S_ISLNK(statbuf.st_mode) || !S_ISDIR(statbuf.st_mode)) {
never@3156	216	// the path represents a link or some non-directory file type,
never@3156	217	// which is not what we expected. declare it insecure.
never@3156	218	//
never@3156	219	return false;
never@3156	220	}
never@3156	221	else {
never@3156	222	// we have an existing directory, check if the permissions are safe.
never@3156	223	//
never@3156	224	if ((statbuf.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
never@3156	225	// the directory is open for writing and could be subjected
never@3156	226	// to a symlnk attack. declare it insecure.
never@3156	227	//
never@3156	228	return false;
never@3156	229	}
never@3156	230	}
never@3156	231	return true;
never@3156	232	}
never@3156	233
never@3156	234
never@3156	235	// return the user name for the given user id
never@3156	236	//
never@3156	237	// the caller is expected to free the allocated memory.
never@3156	238	//
never@3156	239	static char* get_user_name(uid_t uid) {
never@3156	240
never@3156	241	struct passwd pwent;
never@3156	242
never@3156	243	// determine the max pwbuf size from sysconf, and hardcode
never@3156	244	// a default if this not available through sysconf.
never@3156	245	//
never@3156	246	long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
never@3156	247	if (bufsize == -1)
never@3156	248	bufsize = 1024;
never@3156	249
zgu@3900	250	char* pwbuf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
never@3156	251
never@3156	252	// POSIX interface to getpwuid_r is used on LINUX
never@3156	253	struct passwd* p;
never@3156	254	int result = getpwuid_r(uid, &pwent, pwbuf, (size_t)bufsize, &p);
never@3156	255
never@3156	256	if (result != 0 || p == NULL || p->pw_name == NULL || *(p->pw_name) == '\0') {
never@3156	257	if (PrintMiscellaneous && Verbose) {
never@3156	258	if (result != 0) {
never@3156	259	warning("Could not retrieve passwd entry: %s\n",
never@3156	260	strerror(result));
never@3156	261	}
never@3156	262	else if (p == NULL) {
never@3156	263	// this check is added to protect against an observed problem
never@3156	264	// with getpwuid_r() on RedHat 9 where getpwuid_r returns 0,
never@3156	265	// indicating success, but has p == NULL. This was observed when
never@3156	266	// inserting a file descriptor exhaustion fault prior to the call
never@3156	267	// getpwuid_r() call. In this case, error is set to the appropriate
never@3156	268	// error condition, but this is undocumented behavior. This check
never@3156	269	// is safe under any condition, but the use of errno in the output
never@3156	270	// message may result in an erroneous message.
never@3156	271	// Bug Id 89052 was opened with RedHat.
never@3156	272	//
never@3156	273	warning("Could not retrieve passwd entry: %s\n",
never@3156	274	strerror(errno));
never@3156	275	}
never@3156	276	else {
never@3156	277	warning("Could not determine user name: %s\n",
never@3156	278	p->pw_name == NULL ? "pw_name = NULL" :
never@3156	279	"pw_name zero length");
never@3156	280	}
never@3156	281	}
zgu@3900	282	FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal);
never@3156	283	return NULL;
never@3156	284	}
never@3156	285
zgu@3900	286	char* user_name = NEW_C_HEAP_ARRAY(char, strlen(p->pw_name) + 1, mtInternal);
never@3156	287	strcpy(user_name, p->pw_name);
never@3156	288
zgu@3900	289	FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal);
never@3156	290	return user_name;
never@3156	291	}
never@3156	292
never@3156	293	// return the name of the user that owns the process identified by vmid.
never@3156	294	//
never@3156	295	// This method uses a slow directory search algorithm to find the backing
never@3156	296	// store file for the specified vmid and returns the user name, as determined
never@3156	297	// by the user name suffix of the hsperfdata_<username> directory name.
never@3156	298	//
never@3156	299	// the caller is expected to free the allocated memory.
never@3156	300	//
never@3156	301	static char* get_user_name_slow(int vmid, TRAPS) {
never@3156	302
never@3156	303	// short circuit the directory search if the process doesn't even exist.
never@3156	304	if (kill(vmid, 0) == OS_ERR) {
never@3156	305	if (errno == ESRCH) {
never@3156	306	THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
never@3156	307	"Process not found");
never@3156	308	}
never@3156	309	else /* EPERM */ {
never@3156	310	THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
never@3156	311	}
never@3156	312	}
never@3156	313
never@3156	314	// directory search
never@3156	315	char* oldest_user = NULL;
never@3156	316	time_t oldest_ctime = 0;
never@3156	317
never@3156	318	const char* tmpdirname = os::get_temp_directory();
never@3156	319
never@3156	320	DIR* tmpdirp = os::opendir(tmpdirname);
never@3156	321
never@3156	322	if (tmpdirp == NULL) {
never@3156	323	return NULL;
never@3156	324	}
never@3156	325
never@3156	326	// for each entry in the directory that matches the pattern hsperfdata_*,
never@3156	327	// open the directory and check if the file for the given vmid exists.
never@3156	328	// The file with the expected name and the latest creation date is used
never@3156	329	// to determine the user name for the process id.
never@3156	330	//
never@3156	331	struct dirent* dentry;
zgu@3900	332	char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname), mtInternal);
never@3156	333	errno = 0;
never@3156	334	while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) {
never@3156	335
never@3156	336	// check if the directory entry is a hsperfdata file
never@3156	337	if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
never@3156	338	continue;
never@3156	339	}
never@3156	340
never@3156	341	char* usrdir_name = NEW_C_HEAP_ARRAY(char,
zgu@3900	342	strlen(tmpdirname) + strlen(dentry->d_name) + 2, mtInternal);
never@3156	343	strcpy(usrdir_name, tmpdirname);
never@3156	344	strcat(usrdir_name, "/");
never@3156	345	strcat(usrdir_name, dentry->d_name);
never@3156	346
never@3156	347	DIR* subdirp = os::opendir(usrdir_name);
never@3156	348
never@3156	349	if (subdirp == NULL) {
zgu@3900	350	FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
never@3156	351	continue;
never@3156	352	}
never@3156	353
never@3156	354	// Since we don't create the backing store files in directories
never@3156	355	// pointed to by symbolic links, we also don't follow them when
never@3156	356	// looking for the files. We check for a symbolic link after the
never@3156	357	// call to opendir in order to eliminate a small window where the
never@3156	358	// symlink can be exploited.
never@3156	359	//
never@3156	360	if (!is_directory_secure(usrdir_name)) {
zgu@3900	361	FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
never@3156	362	os::closedir(subdirp);
never@3156	363	continue;
never@3156	364	}
never@3156	365
never@3156	366	struct dirent* udentry;
zgu@3900	367	char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name), mtInternal);
never@3156	368	errno = 0;
never@3156	369	while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
never@3156	370
never@3156	371	if (filename_to_pid(udentry->d_name) == vmid) {
never@3156	372	struct stat statbuf;
never@3156	373	int result;
never@3156	374
never@3156	375	char* filename = NEW_C_HEAP_ARRAY(char,
zgu@3900	376	strlen(usrdir_name) + strlen(udentry->d_name) + 2, mtInternal);
never@3156	377
never@3156	378	strcpy(filename, usrdir_name);
never@3156	379	strcat(filename, "/");
never@3156	380	strcat(filename, udentry->d_name);
never@3156	381
never@3156	382	// don't follow symbolic links for the file
never@3156	383	RESTARTABLE(::lstat(filename, &statbuf), result);
never@3156	384	if (result == OS_ERR) {
zgu@3900	385	FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156	386	continue;
never@3156	387	}
never@3156	388
never@3156	389	// skip over files that are not regular files.
never@3156	390	if (!S_ISREG(statbuf.st_mode)) {
zgu@3900	391	FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156	392	continue;
never@3156	393	}
never@3156	394
never@3156	395	// compare and save filename with latest creation time
never@3156	396	if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) {
never@3156	397
never@3156	398	if (statbuf.st_ctime > oldest_ctime) {
never@3156	399	char* user = strchr(dentry->d_name, '_') + 1;
never@3156	400
zgu@3900	401	if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user, mtInternal);
zgu@3900	402	oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
never@3156	403
never@3156	404	strcpy(oldest_user, user);
never@3156	405	oldest_ctime = statbuf.st_ctime;
never@3156	406	}
never@3156	407	}
never@3156	408
zgu@3900	409	FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156	410	}
never@3156	411	}
never@3156	412	os::closedir(subdirp);
zgu@3900	413	FREE_C_HEAP_ARRAY(char, udbuf, mtInternal);
zgu@3900	414	FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
never@3156	415	}
never@3156	416	os::closedir(tmpdirp);
zgu@3900	417	FREE_C_HEAP_ARRAY(char, tdbuf, mtInternal);
never@3156	418
never@3156	419	return(oldest_user);
never@3156	420	}
never@3156	421
never@3156	422	// return the name of the user that owns the JVM indicated by the given vmid.
never@3156	423	//
never@3156	424	static char* get_user_name(int vmid, TRAPS) {
never@3156	425	return get_user_name_slow(vmid, CHECK_NULL);
never@3156	426	}
never@3156	427
never@3156	428	// return the file name of the backing store file for the named
never@3156	429	// shared memory region for the given user name and vmid.
never@3156	430	//
never@3156	431	// the caller is expected to free the allocated memory.
never@3156	432	//
never@3156	433	static char* get_sharedmem_filename(const char* dirname, int vmid) {
never@3156	434
never@3156	435	// add 2 for the file separator and a null terminator.
never@3156	436	size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
never@3156	437
zgu@3900	438	char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
never@3156	439	snprintf(name, nbytes, "%s/%d", dirname, vmid);
never@3156	440
never@3156	441	return name;
never@3156	442	}
never@3156	443
never@3156	444
never@3156	445	// remove file
never@3156	446	//
never@3156	447	// this method removes the file specified by the given path
never@3156	448	//
never@3156	449	static void remove_file(const char* path) {
never@3156	450
never@3156	451	int result;
never@3156	452
never@3156	453	// if the file is a directory, the following unlink will fail. since
never@3156	454	// we don't expect to find directories in the user temp directory, we
never@3156	455	// won't try to handle this situation. even if accidentially or
never@3156	456	// maliciously planted, the directory's presence won't hurt anything.
never@3156	457	//
never@3156	458	RESTARTABLE(::unlink(path), result);
never@3156	459	if (PrintMiscellaneous && Verbose && result == OS_ERR) {
never@3156	460	if (errno != ENOENT) {
never@3156	461	warning("Could not unlink shared memory backing"
never@3156	462	" store file %s : %s\n", path, strerror(errno));
never@3156	463	}
never@3156	464	}
never@3156	465	}
never@3156	466
never@3156	467
never@3156	468	// remove file
never@3156	469	//
never@3156	470	// this method removes the file with the given file name in the
never@3156	471	// named directory.
never@3156	472	//
never@3156	473	static void remove_file(const char* dirname, const char* filename) {
never@3156	474
never@3156	475	size_t nbytes = strlen(dirname) + strlen(filename) + 2;
zgu@3900	476	char* path = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
never@3156	477
never@3156	478	strcpy(path, dirname);
never@3156	479	strcat(path, "/");
never@3156	480	strcat(path, filename);
never@3156	481
never@3156	482	remove_file(path);
never@3156	483
zgu@3900	484	FREE_C_HEAP_ARRAY(char, path, mtInternal);
never@3156	485	}
never@3156	486
never@3156	487
never@3156	488	// cleanup stale shared memory resources
never@3156	489	//
never@3156	490	// This method attempts to remove all stale shared memory files in
never@3156	491	// the named user temporary directory. It scans the named directory
never@3156	492	// for files matching the pattern ^$[0-9]*$. For each file found, the
never@3156	493	// process id is extracted from the file name and a test is run to
never@3156	494	// determine if the process is alive. If the process is not alive,
never@3156	495	// any stale file resources are removed.
never@3156	496	//
never@3156	497	static void cleanup_sharedmem_resources(const char* dirname) {
never@3156	498
never@3156	499	// open the user temp directory
never@3156	500	DIR* dirp = os::opendir(dirname);
never@3156	501
never@3156	502	if (dirp == NULL) {
never@3156	503	// directory doesn't exist, so there is nothing to cleanup
never@3156	504	return;
never@3156	505	}
never@3156	506
never@3156	507	if (!is_directory_secure(dirname)) {
never@3156	508	// the directory is not a secure directory
never@3156	509	return;
never@3156	510	}
never@3156	511
never@3156	512	// for each entry in the directory that matches the expected file
never@3156	513	// name pattern, determine if the file resources are stale and if
never@3156	514	// so, remove the file resources. Note, instrumented HotSpot processes
never@3156	515	// for this user may start and/or terminate during this search and
never@3156	516	// remove or create new files in this directory. The behavior of this
never@3156	517	// loop under these conditions is dependent upon the implementation of
never@3156	518	// opendir/readdir.
never@3156	519	//
never@3156	520	struct dirent* entry;
zgu@3900	521	char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname), mtInternal);
never@3156	522	errno = 0;
never@3156	523	while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) {
never@3156	524
never@3156	525	pid_t pid = filename_to_pid(entry->d_name);
never@3156	526
never@3156	527	if (pid == 0) {
never@3156	528
never@3156	529	if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
never@3156	530
never@3156	531	// attempt to remove all unexpected files, except "." and ".."
never@3156	532	remove_file(dirname, entry->d_name);
never@3156	533	}
never@3156	534
never@3156	535	errno = 0;
never@3156	536	continue;
never@3156	537	}
never@3156	538
never@3156	539	// we now have a file name that converts to a valid integer
never@3156	540	// that could represent a process id . if this process id
never@3156	541	// matches the current process id or the process is not running,
never@3156	542	// then remove the stale file resources.
never@3156	543	//
never@3156	544	// process liveness is detected by sending signal number 0 to
never@3156	545	// the process id (see kill(2)). if kill determines that the
never@3156	546	// process does not exist, then the file resources are removed.
never@3156	547	// if kill determines that that we don't have permission to
never@3156	548	// signal the process, then the file resources are assumed to
never@3156	549	// be stale and are removed because the resources for such a
never@3156	550	// process should be in a different user specific directory.
never@3156	551	//
never@3156	552	if ((pid == os::current_process_id()) ||
never@3156	553	(kill(pid, 0) == OS_ERR && (errno == ESRCH || errno == EPERM))) {
never@3156	554
never@3156	555	remove_file(dirname, entry->d_name);
never@3156	556	}
never@3156	557	errno = 0;
never@3156	558	}
never@3156	559	os::closedir(dirp);
zgu@3900	560	FREE_C_HEAP_ARRAY(char, dbuf, mtInternal);
never@3156	561	}
never@3156	562
never@3156	563	// make the user specific temporary directory. Returns true if
never@3156	564	// the directory exists and is secure upon return. Returns false
never@3156	565	// if the directory exists but is either a symlink, is otherwise
never@3156	566	// insecure, or if an error occurred.
never@3156	567	//
never@3156	568	static bool make_user_tmp_dir(const char* dirname) {
never@3156	569
never@3156	570	// create the directory with 0755 permissions. note that the directory
never@3156	571	// will be owned by euid::egid, which may not be the same as uid::gid.
never@3156	572	//
never@3156	573	if (mkdir(dirname, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) == OS_ERR) {
never@3156	574	if (errno == EEXIST) {
never@3156	575	// The directory already exists and was probably created by another
never@3156	576	// JVM instance. However, this could also be the result of a
never@3156	577	// deliberate symlink. Verify that the existing directory is safe.
never@3156	578	//
never@3156	579	if (!is_directory_secure(dirname)) {
never@3156	580	// directory is not secure
never@3156	581	if (PrintMiscellaneous && Verbose) {
never@3156	582	warning("%s directory is insecure\n", dirname);
never@3156	583	}
never@3156	584	return false;
never@3156	585	}
never@3156	586	}
never@3156	587	else {
never@3156	588	// we encountered some other failure while attempting
never@3156	589	// to create the directory
never@3156	590	//
never@3156	591	if (PrintMiscellaneous && Verbose) {
never@3156	592	warning("could not create directory %s: %s\n",
never@3156	593	dirname, strerror(errno));
never@3156	594	}
never@3156	595	return false;
never@3156	596	}
never@3156	597	}
never@3156	598	return true;
never@3156	599	}
never@3156	600
never@3156	601	// create the shared memory file resources
never@3156	602	//
never@3156	603	// This method creates the shared memory file with the given size
never@3156	604	// This method also creates the user specific temporary directory, if
never@3156	605	// it does not yet exist.
never@3156	606	//
never@3156	607	static int create_sharedmem_resources(const char* dirname, const char* filename, size_t size) {
never@3156	608
never@3156	609	// make the user temporary directory
never@3156	610	if (!make_user_tmp_dir(dirname)) {
never@3156	611	// could not make/find the directory or the found directory
never@3156	612	// was not secure
never@3156	613	return -1;
never@3156	614	}
never@3156	615
never@3156	616	int result;
never@3156	617
never@3156	618	RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_TRUNC, S_IREAD|S_IWRITE), result);
never@3156	619	if (result == OS_ERR) {
never@3156	620	if (PrintMiscellaneous && Verbose) {
never@3156	621	warning("could not create file %s: %s\n", filename, strerror(errno));
never@3156	622	}
never@3156	623	return -1;
never@3156	624	}
never@3156	625
never@3156	626	// save the file descriptor
never@3156	627	int fd = result;
never@3156	628
never@3156	629	// set the file size
never@3156	630	RESTARTABLE(::ftruncate(fd, (off_t)size), result);
never@3156	631	if (result == OS_ERR) {
never@3156	632	if (PrintMiscellaneous && Verbose) {
never@3156	633	warning("could not set shared memory file size: %s\n", strerror(errno));
never@3156	634	}
rdurbin@5264	635	::close(fd);
never@3156	636	return -1;
never@3156	637	}
never@3156	638
never@3156	639	// Verify that we have enough disk space for this file.
never@3156	640	// We'll get random SIGBUS crashes on memory accesses if
never@3156	641	// we don't.
never@3156	642
never@3156	643	for (size_t seekpos = 0; seekpos < size; seekpos += os::vm_page_size()) {
never@3156	644	int zero_int = 0;
never@3156	645	result = (int)os::seek_to_file_offset(fd, (jlong)(seekpos));
never@3156	646	if (result == -1 ) break;
never@3156	647	RESTARTABLE(::write(fd, &zero_int, 1), result);
never@3156	648	if (result != 1) {
never@3156	649	if (errno == ENOSPC) {
never@3156	650	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	651	}
never@3156	652	break;
never@3156	653	}
never@3156	654	}
never@3156	655
never@3156	656	if (result != -1) {
never@3156	657	return fd;
never@3156	658	} else {
rdurbin@5264	659	::close(fd);
never@3156	660	return -1;
never@3156	661	}
never@3156	662	}
never@3156	663
never@3156	664	// open the shared memory file for the given user and vmid. returns
never@3156	665	// the file descriptor for the open file or -1 if the file could not
never@3156	666	// be opened.
never@3156	667	//
never@3156	668	static int open_sharedmem_file(const char* filename, int oflags, TRAPS) {
never@3156	669
never@3156	670	// open the file
never@3156	671	int result;
never@3156	672	RESTARTABLE(::open(filename, oflags), result);
never@3156	673	if (result == OS_ERR) {
never@3156	674	if (errno == ENOENT) {
ccheung@4893	675	THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),
ccheung@4893	676	"Process not found", OS_ERR);
never@3156	677	}
never@3156	678	else if (errno == EACCES) {
ccheung@4893	679	THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),
ccheung@4893	680	"Permission denied", OS_ERR);
never@3156	681	}
never@3156	682	else {
ccheung@4893	683	THROW_MSG_(vmSymbols::java_io_IOException(), strerror(errno), OS_ERR);
never@3156	684	}
never@3156	685	}
never@3156	686
never@3156	687	return result;
never@3156	688	}
never@3156	689
never@3156	690	// create a named shared memory region. returns the address of the
never@3156	691	// memory region on success or NULL on failure. A return value of
never@3156	692	// NULL will ultimately disable the shared memory feature.
never@3156	693	//
never@3156	694	// On Solaris and Bsd, the name space for shared memory objects
never@3156	695	// is the file system name space.
never@3156	696	//
never@3156	697	// A monitoring application attaching to a JVM does not need to know
never@3156	698	// the file system name of the shared memory object. However, it may
never@3156	699	// be convenient for applications to discover the existence of newly
never@3156	700	// created and terminating JVMs by watching the file system name space
never@3156	701	// for files being created or removed.
never@3156	702	//
never@3156	703	static char* mmap_create_shared(size_t size) {
never@3156	704
never@3156	705	int result;
never@3156	706	int fd;
never@3156	707	char* mapAddress;
never@3156	708
never@3156	709	int vmid = os::current_process_id();
never@3156	710
never@3156	711	char* user_name = get_user_name(geteuid());
never@3156	712
never@3156	713	if (user_name == NULL)
never@3156	714	return NULL;
never@3156	715
never@3156	716	char* dirname = get_user_tmp_dir(user_name);
never@3156	717	char* filename = get_sharedmem_filename(dirname, vmid);
never@3156	718
never@3156	719	// cleanup any stale shared memory files
never@3156	720	cleanup_sharedmem_resources(dirname);
never@3156	721
never@3156	722	assert(((size > 0) && (size % os::vm_page_size() == 0)),
never@3156	723	"unexpected PerfMemory region size");
never@3156	724
never@3156	725	fd = create_sharedmem_resources(dirname, filename, size);
never@3156	726
zgu@3900	727	FREE_C_HEAP_ARRAY(char, user_name, mtInternal);
zgu@3900	728	FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
never@3156	729
never@3156	730	if (fd == -1) {
zgu@3900	731	FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156	732	return NULL;
never@3156	733	}
never@3156	734
never@3156	735	mapAddress = (char*)::mmap((char*)0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
never@3156	736
rdurbin@5264	737	result = ::close(fd);
never@3156	738	assert(result != OS_ERR, "could not close file");
never@3156	739
never@3156	740	if (mapAddress == MAP_FAILED) {
never@3156	741	if (PrintMiscellaneous && Verbose) {
never@3156	742	warning("mmap failed - %s\n", strerror(errno));
never@3156	743	}
never@3156	744	remove_file(filename);
zgu@3900	745	FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156	746	return NULL;
never@3156	747	}
never@3156	748
never@3156	749	// save the file name for use in delete_shared_memory()
never@3156	750	backing_store_file_name = filename;
never@3156	751
never@3156	752	// clear the shared memory region
never@3156	753	(void)::memset((void*) mapAddress, 0, size);
never@3156	754
zgu@4193	755	// it does not go through os api, the operation has to record from here
zgu@7074	756	MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress, size, CURRENT_PC, mtInternal);
zgu@4193	757
never@3156	758	return mapAddress;
never@3156	759	}
never@3156	760
never@3156	761	// release a named shared memory region
never@3156	762	//
never@3156	763	static void unmap_shared(char* addr, size_t bytes) {
never@3156	764	os::release_memory(addr, bytes);
never@3156	765	}
never@3156	766
never@3156	767	// create the PerfData memory region in shared memory.
never@3156	768	//
never@3156	769	static char* create_shared_memory(size_t size) {
never@3156	770
never@3156	771	// create the shared memory region.
never@3156	772	return mmap_create_shared(size);
never@3156	773	}
never@3156	774
never@3156	775	// delete the shared PerfData memory region
never@3156	776	//
never@3156	777	static void delete_shared_memory(char* addr, size_t size) {
never@3156	778
never@3156	779	// cleanup the persistent shared memory resources. since DestroyJavaVM does
never@3156	780	// not support unloading of the JVM, unmapping of the memory resource is
never@3156	781	// not performed. The memory will be reclaimed by the OS upon termination of
never@3156	782	// the process. The backing store file is deleted from the file system.
never@3156	783
never@3156	784	assert(!PerfDisableSharedMem, "shouldn't be here");
never@3156	785
never@3156	786	if (backing_store_file_name != NULL) {
never@3156	787	remove_file(backing_store_file_name);
never@3156	788	// Don't.. Free heap memory could deadlock os::abort() if it is called
never@3156	789	// from signal handler. OS will reclaim the heap memory.
never@3156	790	// FREE_C_HEAP_ARRAY(char, backing_store_file_name);
never@3156	791	backing_store_file_name = NULL;
never@3156	792	}
never@3156	793	}
never@3156	794
never@3156	795	// return the size of the file for the given file descriptor
never@3156	796	// or 0 if it is not a valid size for a shared memory file
never@3156	797	//
never@3156	798	static size_t sharedmem_filesize(int fd, TRAPS) {
never@3156	799
never@3156	800	struct stat statbuf;
never@3156	801	int result;
never@3156	802
never@3156	803	RESTARTABLE(::fstat(fd, &statbuf), result);
never@3156	804	if (result == OS_ERR) {
never@3156	805	if (PrintMiscellaneous && Verbose) {
never@3156	806	warning("fstat failed: %s\n", strerror(errno));
never@3156	807	}
never@3156	808	THROW_MSG_0(vmSymbols::java_io_IOException(),
never@3156	809	"Could not determine PerfMemory size");
never@3156	810	}
never@3156	811
never@3156	812	if ((statbuf.st_size == 0) ||
never@3156	813	((size_t)statbuf.st_size % os::vm_page_size() != 0)) {
never@3156	814	THROW_MSG_0(vmSymbols::java_lang_Exception(),
never@3156	815	"Invalid PerfMemory size");
never@3156	816	}
never@3156	817
never@3156	818	return (size_t)statbuf.st_size;
never@3156	819	}
never@3156	820
never@3156	821	// attach to a named shared memory region.
never@3156	822	//
never@3156	823	static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemoryMode mode, char** addr, size_t* sizep, TRAPS) {
never@3156	824
never@3156	825	char* mapAddress;
never@3156	826	int result;
never@3156	827	int fd;
ccheung@4893	828	size_t size = 0;
never@3156	829	const char* luser = NULL;
never@3156	830
never@3156	831	int mmap_prot;
never@3156	832	int file_flags;
never@3156	833
never@3156	834	ResourceMark rm;
never@3156	835
never@3156	836	// map the high level access mode to the appropriate permission
never@3156	837	// constructs for the file and the shared memory mapping.
never@3156	838	if (mode == PerfMemory::PERF_MODE_RO) {
never@3156	839	mmap_prot = PROT_READ;
never@3156	840	file_flags = O_RDONLY;
never@3156	841	}
never@3156	842	else if (mode == PerfMemory::PERF_MODE_RW) {
never@3156	843	#ifdef LATER
never@3156	844	mmap_prot = PROT_READ | PROT_WRITE;
never@3156	845	file_flags = O_RDWR;
never@3156	846	#else
never@3156	847	THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
never@3156	848	"Unsupported access mode");
never@3156	849	#endif
never@3156	850	}
never@3156	851	else {
never@3156	852	THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
never@3156	853	"Illegal access mode");
never@3156	854	}
never@3156	855
never@3156	856	if (user == NULL || strlen(user) == 0) {
never@3156	857	luser = get_user_name(vmid, CHECK);
never@3156	858	}
never@3156	859	else {
never@3156	860	luser = user;
never@3156	861	}
never@3156	862
never@3156	863	if (luser == NULL) {
never@3156	864	THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
never@3156	865	"Could not map vmid to user Name");
never@3156	866	}
never@3156	867
never@3156	868	char* dirname = get_user_tmp_dir(luser);
never@3156	869
never@3156	870	// since we don't follow symbolic links when creating the backing
never@3156	871	// store file, we don't follow them when attaching either.
never@3156	872	//
never@3156	873	if (!is_directory_secure(dirname)) {
zgu@3900	874	FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
never@3156	875	THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
never@3156	876	"Process not found");
never@3156	877	}
never@3156	878
never@3156	879	char* filename = get_sharedmem_filename(dirname, vmid);
never@3156	880
never@3156	881	// copy heap memory to resource memory. the open_sharedmem_file
never@3156	882	// method below need to use the filename, but could throw an
never@3156	883	// exception. using a resource array prevents the leak that
never@3156	884	// would otherwise occur.
never@3156	885	char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
never@3156	886	strcpy(rfilename, filename);
never@3156	887
never@3156	888	// free the c heap resources that are no longer needed
zgu@3900	889	if (luser != user) FREE_C_HEAP_ARRAY(char, luser, mtInternal);
zgu@3900	890	FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
zgu@3900	891	FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156	892
never@3156	893	// open the shared memory file for the give vmid
never@3156	894	fd = open_sharedmem_file(rfilename, file_flags, CHECK);
never@3156	895	assert(fd != OS_ERR, "unexpected value");
never@3156	896
never@3156	897	if (*sizep == 0) {
never@3156	898	size = sharedmem_filesize(fd, CHECK);
ccheung@4893	899	} else {
ccheung@4893	900	size = *sizep;
never@3156	901	}
never@3156	902
ccheung@4893	903	assert(size > 0, "unexpected size <= 0");
ccheung@4893	904
never@3156	905	mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0);
never@3156	906
never@3156	907	// attempt to close the file - restart if it gets interrupted,
never@3156	908	// but ignore other failures
rdurbin@5264	909	result = ::close(fd);
never@3156	910	assert(result != OS_ERR, "could not close file");
never@3156	911
never@3156	912	if (mapAddress == MAP_FAILED) {
never@3156	913	if (PrintMiscellaneous && Verbose) {
never@3156	914	warning("mmap failed: %s\n", strerror(errno));
never@3156	915	}
never@3156	916	THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
never@3156	917	"Could not map PerfMemory");
never@3156	918	}
never@3156	919
zgu@4193	920	// it does not go through os api, the operation has to record from here
zgu@7074	921	MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress, size, CURRENT_PC, mtInternal);
zgu@4193	922
never@3156	923	*addr = mapAddress;
never@3156	924	*sizep = size;
never@3156	925
never@3156	926	if (PerfTraceMemOps) {
never@3156	927	tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at "
drchase@6680	928	INTPTR_FORMAT "\n", size, vmid, p2i((void*)mapAddress));
never@3156	929	}
never@3156	930	}
never@3156	931
never@3156	932
never@3156	933
never@3156	934
never@3156	935	// create the PerfData memory region
never@3156	936	//
never@3156	937	// This method creates the memory region used to store performance
never@3156	938	// data for the JVM. The memory may be created in standard or
never@3156	939	// shared memory.
never@3156	940	//
never@3156	941	void PerfMemory::create_memory_region(size_t size) {
never@3156	942
never@3156	943	if (PerfDisableSharedMem) {
never@3156	944	// do not share the memory for the performance data.
never@3156	945	_start = create_standard_memory(size);
never@3156	946	}
never@3156	947	else {
never@3156	948	_start = create_shared_memory(size);
never@3156	949	if (_start == NULL) {
never@3156	950
never@3156	951	// creation of the shared memory region failed, attempt
never@3156	952	// to create a contiguous, non-shared memory region instead.
never@3156	953	//
never@3156	954	if (PrintMiscellaneous && Verbose) {
never@3156	955	warning("Reverting to non-shared PerfMemory region.\n");
never@3156	956	}
never@3156	957	PerfDisableSharedMem = true;
never@3156	958	_start = create_standard_memory(size);
never@3156	959	}
never@3156	960	}
never@3156	961
never@3156	962	if (_start != NULL) _capacity = size;
never@3156	963
never@3156	964	}
never@3156	965
never@3156	966	// delete the PerfData memory region
never@3156	967	//
never@3156	968	// This method deletes the memory region used to store performance
never@3156	969	// data for the JVM. The memory region indicated by the <address, size>
never@3156	970	// tuple will be inaccessible after a call to this method.
never@3156	971	//
never@3156	972	void PerfMemory::delete_memory_region() {
never@3156	973
never@3156	974	assert((start() != NULL && capacity() > 0), "verify proper state");
never@3156	975
never@3156	976	// If user specifies PerfDataSaveFile, it will save the performance data
never@3156	977	// to the specified file name no matter whether PerfDataSaveToFile is specified
never@3156	978	// or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
never@3156	979	// -XX:+PerfDataSaveToFile.
never@3156	980	if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
never@3156	981	save_memory_to_file(start(), capacity());
never@3156	982	}
never@3156	983
never@3156	984	if (PerfDisableSharedMem) {
never@3156	985	delete_standard_memory(start(), capacity());
never@3156	986	}
never@3156	987	else {
never@3156	988	delete_shared_memory(start(), capacity());
never@3156	989	}
never@3156	990	}
never@3156	991
never@3156	992	// attach to the PerfData memory region for another JVM
never@3156	993	//
never@3156	994	// This method returns an <address, size> tuple that points to
never@3156	995	// a memory buffer that is kept reasonably synchronized with
never@3156	996	// the PerfData memory region for the indicated JVM. This
never@3156	997	// buffer may be kept in synchronization via shared memory
never@3156	998	// or some other mechanism that keeps the buffer updated.
never@3156	999	//
never@3156	1000	// If the JVM chooses not to support the attachability feature,
never@3156	1001	// this method should throw an UnsupportedOperation exception.
never@3156	1002	//
never@3156	1003	// This implementation utilizes named shared memory to map
never@3156	1004	// the indicated process's PerfData memory region into this JVMs
never@3156	1005	// address space.
never@3156	1006	//
never@3156	1007	void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, char** addrp, size_t* sizep, TRAPS) {
never@3156	1008
never@3156	1009	if (vmid == 0 || vmid == os::current_process_id()) {
never@3156	1010	*addrp = start();
never@3156	1011	*sizep = capacity();
never@3156	1012	return;
never@3156	1013	}
never@3156	1014
never@3156	1015	mmap_attach_shared(user, vmid, mode, addrp, sizep, CHECK);
never@3156	1016	}
never@3156	1017
never@3156	1018	// detach from the PerfData memory region of another JVM
never@3156	1019	//
never@3156	1020	// This method detaches the PerfData memory region of another
never@3156	1021	// JVM, specified as an <address, size> tuple of a buffer
never@3156	1022	// in this process's address space. This method may perform
never@3156	1023	// arbitrary actions to accomplish the detachment. The memory
never@3156	1024	// region specified by <address, size> will be inaccessible after
never@3156	1025	// a call to this method.
never@3156	1026	//
never@3156	1027	// If the JVM chooses not to support the attachability feature,
never@3156	1028	// this method should throw an UnsupportedOperation exception.
never@3156	1029	//
never@3156	1030	// This implementation utilizes named shared memory to detach
never@3156	1031	// the indicated process's PerfData memory region from this
never@3156	1032	// process's address space.
never@3156	1033	//
never@3156	1034	void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
never@3156	1035
never@3156	1036	assert(addr != 0, "address sanity check");
never@3156	1037	assert(bytes > 0, "capacity sanity check");
never@3156	1038
never@3156	1039	if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
never@3156	1040	// prevent accidental detachment of this process's PerfMemory region
never@3156	1041	return;
never@3156	1042	}
never@3156	1043
never@3156	1044	unmap_shared(addr, bytes);
never@3156	1045	}
never@3156	1046
never@3156	1047	char* PerfMemory::backing_store_filename() {
never@3156	1048	return backing_store_file_name;
never@3156	1049	}