truffle: src/os/linux/vm/perfMemory

comparison src/os/linux/vm/perfMemory_linux.cpp @ 0:a61af66fc99e jdk7-b24

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author	duke
date	Sat, 01 Dec 2007 00:00:00 +0000
parents
children	98cb887364d3

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equal deleted inserted replaced

--1:000000000000
+:a61af66fc99e
+/*
+* Copyright 2001-2006 Sun Microsystems, Inc.  All Rights Reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+* CA 95054 USA or visit www.sun.com if you need additional information or
+* have any questions.
+*
+*/
+# include "incls/_precompiled.incl"
+# include "incls/_perfMemory_linux.cpp.incl"
+// put OS-includes here
+# include <sys/types.h>
+# include <sys/mman.h>
+# include <errno.h>
+# include <stdio.h>
+# include <unistd.h>
+# include <sys/stat.h>
+# include <signal.h>
+# include <pwd.h>
+static char* backing_store_file_name = NULL;  // name of the backing store
+// file, if successfully created.
+// Standard Memory Implementation Details
+// create the PerfData memory region in standard memory.
+//
+static char* create_standard_memory(size_t size) {
+// allocate an aligned chuck of memory
+char* mapAddress = os::reserve_memory(size);
+if (mapAddress == NULL) {
+return NULL;
+}
+// commit memory
+if (!os::commit_memory(mapAddress, size)) {
+if (PrintMiscellaneous && Verbose) {
+warning("Could not commit PerfData memory\n");
+}
+os::release_memory(mapAddress, size);
+return NULL;
+}
+return mapAddress;
+}
+// delete the PerfData memory region
+//
+static void delete_standard_memory(char* addr, size_t size) {
+// there are no persistent external resources to cleanup for standard
+// memory. since DestroyJavaVM does not support unloading of the JVM,
+// cleanup of the memory resource is not performed. The memory will be
+// reclaimed by the OS upon termination of the process.
+//
+return;
+}
+// save the specified memory region to the given file
+//
+// Note: this function might be called from signal handler (by os::abort()),
+// don't allocate heap memory.
+//
+static void save_memory_to_file(char* addr, size_t size) {
+const char* destfile = PerfMemory::get_perfdata_file_path();
+assert(destfile[0] != '\0', "invalid PerfData file path");
+int result;
+RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE),
+result);;
+if (result == OS_ERR) {
+if (PrintMiscellaneous && Verbose) {
+warning("Could not create Perfdata save file: %s: %s\n",
+destfile, strerror(errno));
+}
+} else {
+int fd = result;
+for (size_t remaining = size; remaining > 0;) {
+RESTARTABLE(::write(fd, addr, remaining), result);
+if (result == OS_ERR) {
+if (PrintMiscellaneous && Verbose) {
+warning("Could not write Perfdata save file: %s: %s\n",
+destfile, strerror(errno));
+}
+break;
+}
+remaining -= (size_t)result;
+addr += result;
+}
+RESTARTABLE(::close(fd), result);
+if (PrintMiscellaneous && Verbose) {
+if (result == OS_ERR) {
+warning("Could not close %s: %s\n", destfile, strerror(errno));
+}
+}
+}
+FREE_C_HEAP_ARRAY(char, destfile);
+}
+// Shared Memory Implementation Details
+// Note: the solaris and linux shared memory implementation uses the mmap
+// interface with a backing store file to implement named shared memory.
+// Using the file system as the name space for shared memory allows a
+// common name space to be supported across a variety of platforms. It
+// also provides a name space that Java applications can deal with through
+// simple file apis.
+//
+// The solaris and linux implementations store the backing store file in
+// a user specific temporary directory located in the /tmp file system,
+// which is always a local file system and is sometimes a RAM based file
+// system.
+// return the user specific temporary directory name.
+//
+// the caller is expected to free the allocated memory.
+//
+static char* get_user_tmp_dir(const char* user) {
+const char* tmpdir = os::get_temp_directory();
+const char* perfdir = PERFDATA_NAME;
+size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 2;
+char* dirname = NEW_C_HEAP_ARRAY(char, nbytes);
+// construct the path name to user specific tmp directory
+snprintf(dirname, nbytes, "%s%s_%s", tmpdir, perfdir, user);
+return dirname;
+}
+// convert the given file name into a process id. if the file
+// does not meet the file naming constraints, return 0.
+//
+static pid_t filename_to_pid(const char* filename) {
+// a filename that doesn't begin with a digit is not a
+// candidate for conversion.
+//
+if (!isdigit(*filename)) {
+return 0;
+}
+// check if file name can be converted to an integer without
+// any leftover characters.
+//
+char* remainder = NULL;
+errno = 0;
+pid_t pid = (pid_t)strtol(filename, &remainder, 10);
+if (errno != 0) {
+return 0;
+}
+// check for left over characters. If any, then the filename is
+// not a candidate for conversion.
+//
+if (remainder != NULL && *remainder != '\0') {
+return 0;
+}
+// successful conversion, return the pid
+return pid;
+}
+// check if the given path is considered a secure directory for
+// the backing store files. Returns true if the directory exists
+// and is considered a secure location. Returns false if the path
+// is a symbolic link or if an error occured.
+//
+static bool is_directory_secure(const char* path) {
+struct stat statbuf;
+int result = 0;
+RESTARTABLE(::lstat(path, &statbuf), result);
+if (result == OS_ERR) {
+return false;
+}
+// the path exists, now check it's mode
+if (S_ISLNK(statbuf.st_mode) || !S_ISDIR(statbuf.st_mode)) {
+// the path represents a link or some non-directory file type,
+// which is not what we expected. declare it insecure.
+//
+return false;
+}
+else {
+// we have an existing directory, check if the permissions are safe.
+//
+if ((statbuf.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
+// the directory is open for writing and could be subjected
+// to a symlnk attack. declare it insecure.
+//
+return false;
+}
+}
+return true;
+}
+// return the user name for the given user id
+//
+// the caller is expected to free the allocated memory.
+//
+static char* get_user_name(uid_t uid) {
+struct passwd pwent;
+// determine the max pwbuf size from sysconf, and hardcode
+// a default if this not available through sysconf.
+//
+long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
+if (bufsize == -1)
+bufsize = 1024;
+char* pwbuf = NEW_C_HEAP_ARRAY(char, bufsize);
+// POSIX interface to getpwuid_r is used on LINUX
+struct passwd* p;
+int result = getpwuid_r(uid, &pwent, pwbuf, (size_t)bufsize, &p);
+if (result != 0 || p == NULL || p->pw_name == NULL || *(p->pw_name) == '\0') {
+if (PrintMiscellaneous && Verbose) {
+if (result != 0) {
+warning("Could not retrieve passwd entry: %s\n",
+strerror(result));
+}
+else if (p == NULL) {
+// this check is added to protect against an observed problem
+// with getpwuid_r() on RedHat 9 where getpwuid_r returns 0,
+// indicating success, but has p == NULL. This was observed when
+// inserting a file descriptor exhaustion fault prior to the call
+// getpwuid_r() call. In this case, error is set to the appropriate
+// error condition, but this is undocumented behavior. This check
+// is safe under any condition, but the use of errno in the output
+// message may result in an erroneous message.
+// Bug Id 89052 was opened with RedHat.
+//
+warning("Could not retrieve passwd entry: %s\n",
+strerror(errno));
+}
+else {
+warning("Could not determine user name: %s\n",
+p->pw_name == NULL ? "pw_name = NULL" :
+"pw_name zero length");
+}
+}
+FREE_C_HEAP_ARRAY(char, pwbuf);
+return NULL;
+}
+char* user_name = NEW_C_HEAP_ARRAY(char, strlen(p->pw_name) + 1);
+strcpy(user_name, p->pw_name);
+FREE_C_HEAP_ARRAY(char, pwbuf);
+return user_name;
+}
+// return the name of the user that owns the process identified by vmid.
+//
+// This method uses a slow directory search algorithm to find the backing
+// store file for the specified vmid and returns the user name, as determined
+// by the user name suffix of the hsperfdata_<username> directory name.
+//
+// the caller is expected to free the allocated memory.
+//
+static char* get_user_name_slow(int vmid, TRAPS) {
+// short circuit the directory search if the process doesn't even exist.
+if (kill(vmid, 0) == OS_ERR) {
+if (errno == ESRCH) {
+THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
+"Process not found");
+}
+else /* EPERM */ {
+THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
+}
+}
+// directory search
+char* oldest_user = NULL;
+time_t oldest_ctime = 0;
+const char* tmpdirname = os::get_temp_directory();
+DIR* tmpdirp = os::opendir(tmpdirname);
+if (tmpdirp == NULL) {
+return NULL;
+}
+// for each entry in the directory that matches the pattern hsperfdata_*,
+// open the directory and check if the file for the given vmid exists.
+// The file with the expected name and the latest creation date is used
+// to determine the user name for the process id.
+//
+struct dirent* dentry;
+char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname));
+errno = 0;
+while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) {
+// check if the directory entry is a hsperfdata file
+if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
+continue;
+}
+char* usrdir_name = NEW_C_HEAP_ARRAY(char,
+strlen(tmpdirname) + strlen(dentry->d_name) + 1);
+strcpy(usrdir_name, tmpdirname);
+strcat(usrdir_name, dentry->d_name);
+DIR* subdirp = os::opendir(usrdir_name);
+if (subdirp == NULL) {
+FREE_C_HEAP_ARRAY(char, usrdir_name);
+continue;
+}
+// Since we don't create the backing store files in directories
+// pointed to by symbolic links, we also don't follow them when
+// looking for the files. We check for a symbolic link after the
+// call to opendir in order to eliminate a small window where the
+// symlink can be exploited.
+//
+if (!is_directory_secure(usrdir_name)) {
+FREE_C_HEAP_ARRAY(char, usrdir_name);
+os::closedir(subdirp);
+continue;
+}
+struct dirent* udentry;
+char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name));
+errno = 0;
+while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
+if (filename_to_pid(udentry->d_name) == vmid) {
+struct stat statbuf;
+int result;
+char* filename = NEW_C_HEAP_ARRAY(char,
+strlen(usrdir_name) + strlen(udentry->d_name) + 2);
+strcpy(filename, usrdir_name);
+strcat(filename, "/");
+strcat(filename, udentry->d_name);
+// don't follow symbolic links for the file
+RESTARTABLE(::lstat(filename, &statbuf), result);
+if (result == OS_ERR) {
+FREE_C_HEAP_ARRAY(char, filename);
+continue;
+}
+// skip over files that are not regular files.
+if (!S_ISREG(statbuf.st_mode)) {
+FREE_C_HEAP_ARRAY(char, filename);
+continue;
+}
+// compare and save filename with latest creation time
+if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) {
+if (statbuf.st_ctime > oldest_ctime) {
+char* user = strchr(dentry->d_name, '_') + 1;
+if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user);
+oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1);
+strcpy(oldest_user, user);
+oldest_ctime = statbuf.st_ctime;
+}
+}
+FREE_C_HEAP_ARRAY(char, filename);
+}
+}
+os::closedir(subdirp);
+FREE_C_HEAP_ARRAY(char, udbuf);
+FREE_C_HEAP_ARRAY(char, usrdir_name);
+}
+os::closedir(tmpdirp);
+FREE_C_HEAP_ARRAY(char, tdbuf);
+return(oldest_user);
+}
+// return the name of the user that owns the JVM indicated by the given vmid.
+//
+static char* get_user_name(int vmid, TRAPS) {
+return get_user_name_slow(vmid, CHECK_NULL);
+}
+// return the file name of the backing store file for the named
+// shared memory region for the given user name and vmid.
+//
+// the caller is expected to free the allocated memory.
+//
+static char* get_sharedmem_filename(const char* dirname, int vmid) {
+// add 2 for the file separator and a null terminator.
+size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
+char* name = NEW_C_HEAP_ARRAY(char, nbytes);
+snprintf(name, nbytes, "%s/%d", dirname, vmid);
+return name;
+}
+// remove file
+//
+// this method removes the file specified by the given path
+//
+static void remove_file(const char* path) {
+int result;
+// if the file is a directory, the following unlink will fail. since
+// we don't expect to find directories in the user temp directory, we
+// won't try to handle this situation. even if accidentially or
+// maliciously planted, the directory's presence won't hurt anything.
+//
+RESTARTABLE(::unlink(path), result);
+if (PrintMiscellaneous && Verbose && result == OS_ERR) {
+if (errno != ENOENT) {
+warning("Could not unlink shared memory backing"
+" store file %s : %s\n", path, strerror(errno));
+}
+}
+}
+// remove file
+//
+// this method removes the file with the given file name in the
+// named directory.
+//
+static void remove_file(const char* dirname, const char* filename) {
+size_t nbytes = strlen(dirname) + strlen(filename) + 2;
+char* path = NEW_C_HEAP_ARRAY(char, nbytes);
+strcpy(path, dirname);
+strcat(path, "/");
+strcat(path, filename);
+remove_file(path);
+FREE_C_HEAP_ARRAY(char, path);
+}
+// cleanup stale shared memory resources
+//
+// This method attempts to remove all stale shared memory files in
+// the named user temporary directory. It scans the named directory
+// for files matching the pattern ^$[0-9]*$. For each file found, the
+// process id is extracted from the file name and a test is run to
+// determine if the process is alive. If the process is not alive,
+// any stale file resources are removed.
+//
+static void cleanup_sharedmem_resources(const char* dirname) {
+// open the user temp directory
+DIR* dirp = os::opendir(dirname);
+if (dirp == NULL) {
+// directory doesn't exist, so there is nothing to cleanup
+return;
+}
+if (!is_directory_secure(dirname)) {
+// the directory is not a secure directory
+return;
+}
+// for each entry in the directory that matches the expected file
+// name pattern, determine if the file resources are stale and if
+// so, remove the file resources. Note, instrumented HotSpot processes
+// for this user may start and/or terminate during this search and
+// remove or create new files in this directory. The behavior of this
+// loop under these conditions is dependent upon the implementation of
+// opendir/readdir.
+//
+struct dirent* entry;
+char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname));
+errno = 0;
+while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) {
+pid_t pid = filename_to_pid(entry->d_name);
+if (pid == 0) {
+if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
+// attempt to remove all unexpected files, except "." and ".."
+remove_file(dirname, entry->d_name);
+}
+errno = 0;
+continue;
+}
+// we now have a file name that converts to a valid integer
+// that could represent a process id . if this process id
+// matches the current process id or the process is not running,
+// then remove the stale file resources.
+//
+// process liveness is detected by sending signal number 0 to
+// the process id (see kill(2)). if kill determines that the
+// process does not exist, then the file resources are removed.
+// if kill determines that that we don't have permission to
+// signal the process, then the file resources are assumed to
+// be stale and are removed because the resources for such a
+// process should be in a different user specific directory.
+//
+if ((pid == os::current_process_id()) ||
+(kill(pid, 0) == OS_ERR && (errno == ESRCH || errno == EPERM))) {
+remove_file(dirname, entry->d_name);
+}
+errno = 0;
+}
+os::closedir(dirp);
+FREE_C_HEAP_ARRAY(char, dbuf);
+}
+// make the user specific temporary directory. Returns true if
+// the directory exists and is secure upon return. Returns false
+// if the directory exists but is either a symlink, is otherwise
+// insecure, or if an error occurred.
+//
+static bool make_user_tmp_dir(const char* dirname) {
+// create the directory with 0755 permissions. note that the directory
+// will be owned by euid::egid, which may not be the same as uid::gid.
+//
+if (mkdir(dirname, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) == OS_ERR) {
+if (errno == EEXIST) {
+// The directory already exists and was probably created by another
+// JVM instance. However, this could also be the result of a
+// deliberate symlink. Verify that the existing directory is safe.
+//
+if (!is_directory_secure(dirname)) {
+// directory is not secure
+if (PrintMiscellaneous && Verbose) {
+warning("%s directory is insecure\n", dirname);
+}
+return false;
+}
+}
+else {
+// we encountered some other failure while attempting
+// to create the directory
+//
+if (PrintMiscellaneous && Verbose) {
+warning("could not create directory %s: %s\n",
+dirname, strerror(errno));
+}
+return false;
+}
+}
+return true;
+}
+// create the shared memory file resources
+//
+// This method creates the shared memory file with the given size
+// This method also creates the user specific temporary directory, if
+// it does not yet exist.
+//
+static int create_sharedmem_resources(const char* dirname, const char* filename, size_t size) {
+// make the user temporary directory
+if (!make_user_tmp_dir(dirname)) {
+// could not make/find the directory or the found directory
+// was not secure
+return -1;
+}
+int result;
+RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_TRUNC, S_IREAD|S_IWRITE), result);
+if (result == OS_ERR) {
+if (PrintMiscellaneous && Verbose) {
+warning("could not create file %s: %s\n", filename, strerror(errno));
+}
+return -1;
+}
+// save the file descriptor
+int fd = result;
+// set the file size
+RESTARTABLE(::ftruncate(fd, (off_t)size), result);
+if (result == OS_ERR) {
+if (PrintMiscellaneous && Verbose) {
+warning("could not set shared memory file size: %s\n", strerror(errno));
+}
+RESTARTABLE(::close(fd), result);
+return -1;
+}
+return fd;
+}
+// open the shared memory file for the given user and vmid. returns
+// the file descriptor for the open file or -1 if the file could not
+// be opened.
+//
+static int open_sharedmem_file(const char* filename, int oflags, TRAPS) {
+// open the file
+int result;
+RESTARTABLE(::open(filename, oflags), result);
+if (result == OS_ERR) {
+if (errno == ENOENT) {
+THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
+"Process not found");
+}
+else if (errno == EACCES) {
+THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
+"Permission denied");
+}
+else {
+THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
+}
+}
+return result;
+}
+// create a named shared memory region. returns the address of the
+// memory region on success or NULL on failure. A return value of
+// NULL will ultimately disable the shared memory feature.
+//
+// On Solaris and Linux, the name space for shared memory objects
+// is the file system name space.
+//
+// A monitoring application attaching to a JVM does not need to know
+// the file system name of the shared memory object. However, it may
+// be convenient for applications to discover the existence of newly
+// created and terminating JVMs by watching the file system name space
+// for files being created or removed.
+//
+static char* mmap_create_shared(size_t size) {
+int result;
+int fd;
+char* mapAddress;
+int vmid = os::current_process_id();
+char* user_name = get_user_name(geteuid());
+if (user_name == NULL)
+return NULL;
+char* dirname = get_user_tmp_dir(user_name);
+char* filename = get_sharedmem_filename(dirname, vmid);
+// cleanup any stale shared memory files
+cleanup_sharedmem_resources(dirname);
+assert(((size > 0) && (size % os::vm_page_size() == 0)),
+"unexpected PerfMemory region size");
+fd = create_sharedmem_resources(dirname, filename, size);
+FREE_C_HEAP_ARRAY(char, user_name);
+FREE_C_HEAP_ARRAY(char, dirname);
+if (fd == -1) {
+FREE_C_HEAP_ARRAY(char, filename);
+return NULL;
+}
+mapAddress = (char*)::mmap((char*)0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+// attempt to close the file - restart it if it was interrupted,
+// but ignore other failures
+RESTARTABLE(::close(fd), result);
+assert(result != OS_ERR, "could not close file");
+if (mapAddress == MAP_FAILED) {
+if (PrintMiscellaneous && Verbose) {
+warning("mmap failed -  %s\n", strerror(errno));
+}
+remove_file(filename);
+FREE_C_HEAP_ARRAY(char, filename);
+return NULL;
+}
+// save the file name for use in delete_shared_memory()
+backing_store_file_name = filename;
+// clear the shared memory region
+(void)::memset((void*) mapAddress, 0, size);
+return mapAddress;
+}
+// release a named shared memory region
+//
+static void unmap_shared(char* addr, size_t bytes) {
+os::release_memory(addr, bytes);
+}
+// create the PerfData memory region in shared memory.
+//
+static char* create_shared_memory(size_t size) {
+// create the shared memory region.
+return mmap_create_shared(size);
+}
+// delete the shared PerfData memory region
+//
+static void delete_shared_memory(char* addr, size_t size) {
+// cleanup the persistent shared memory resources. since DestroyJavaVM does
+// not support unloading of the JVM, unmapping of the memory resource is
+// not performed. The memory will be reclaimed by the OS upon termination of
+// the process. The backing store file is deleted from the file system.
+assert(!PerfDisableSharedMem, "shouldn't be here");
+if (backing_store_file_name != NULL) {
+remove_file(backing_store_file_name);
+// Don't.. Free heap memory could deadlock os::abort() if it is called
+// from signal handler. OS will reclaim the heap memory.
+// FREE_C_HEAP_ARRAY(char, backing_store_file_name);
+backing_store_file_name = NULL;
+}
+}
+// return the size of the file for the given file descriptor
+// or 0 if it is not a valid size for a shared memory file
+//
+static size_t sharedmem_filesize(int fd, TRAPS) {
+struct stat statbuf;
+int result;
+RESTARTABLE(::fstat(fd, &statbuf), result);
+if (result == OS_ERR) {
+if (PrintMiscellaneous && Verbose) {
+warning("fstat failed: %s\n", strerror(errno));
+}
+THROW_MSG_0(vmSymbols::java_io_IOException(),
+"Could not determine PerfMemory size");
+}
+if ((statbuf.st_size == 0) ||
+((size_t)statbuf.st_size % os::vm_page_size() != 0)) {
+THROW_MSG_0(vmSymbols::java_lang_Exception(),
+"Invalid PerfMemory size");
+}
+return (size_t)statbuf.st_size;
+}
+// attach to a named shared memory region.
+//
+static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemoryMode mode, char** addr, size_t* sizep, TRAPS) {
+char* mapAddress;
+int result;
+int fd;
+size_t size;
+const char* luser = NULL;
+int mmap_prot;
+int file_flags;
+ResourceMark rm;
+// map the high level access mode to the appropriate permission
+// constructs for the file and the shared memory mapping.
+if (mode == PerfMemory::PERF_MODE_RO) {
+mmap_prot = PROT_READ;
+file_flags = O_RDONLY;
+}
+else if (mode == PerfMemory::PERF_MODE_RW) {
+#ifdef LATER
+mmap_prot = PROT_READ | PROT_WRITE;
+file_flags = O_RDWR;
+#else
+THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
+"Unsupported access mode");
+#endif
+}
+else {
+THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
+"Illegal access mode");
+}
+if (user == NULL || strlen(user) == 0) {
+luser = get_user_name(vmid, CHECK);
+}
+else {
+luser = user;
+}
+if (luser == NULL) {
+THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
+"Could not map vmid to user Name");
+}
+char* dirname = get_user_tmp_dir(luser);
+// since we don't follow symbolic links when creating the backing
+// store file, we don't follow them when attaching either.
+//
+if (!is_directory_secure(dirname)) {
+FREE_C_HEAP_ARRAY(char, dirname);
+THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
+"Process not found");
+}
+char* filename = get_sharedmem_filename(dirname, vmid);
+// copy heap memory to resource memory. the open_sharedmem_file
+// method below need to use the filename, but could throw an
+// exception. using a resource array prevents the leak that
+// would otherwise occur.
+char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
+strcpy(rfilename, filename);
+// free the c heap resources that are no longer needed
+if (luser != user) FREE_C_HEAP_ARRAY(char, luser);
+FREE_C_HEAP_ARRAY(char, dirname);
+FREE_C_HEAP_ARRAY(char, filename);
+// open the shared memory file for the give vmid
+fd = open_sharedmem_file(rfilename, file_flags, CHECK);
+assert(fd != OS_ERR, "unexpected value");
+if (*sizep == 0) {
+size = sharedmem_filesize(fd, CHECK);
+assert(size != 0, "unexpected size");
+}
+mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0);
+// attempt to close the file - restart if it gets interrupted,
+// but ignore other failures
+RESTARTABLE(::close(fd), result);
+assert(result != OS_ERR, "could not close file");
+if (mapAddress == MAP_FAILED) {
+if (PrintMiscellaneous && Verbose) {
+warning("mmap failed: %s\n", strerror(errno));
+}
+THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
+"Could not map PerfMemory");
+}
+*addr = mapAddress;
+*sizep = size;
+if (PerfTraceMemOps) {
+tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at "
+INTPTR_FORMAT "\n", size, vmid, (void*)mapAddress);
+}
+}
+// create the PerfData memory region
+//
+// This method creates the memory region used to store performance
+// data for the JVM. The memory may be created in standard or
+// shared memory.
+//
+void PerfMemory::create_memory_region(size_t size) {
+if (PerfDisableSharedMem) {
+// do not share the memory for the performance data.
+_start = create_standard_memory(size);
+}
+else {
+_start = create_shared_memory(size);
+if (_start == NULL) {
+// creation of the shared memory region failed, attempt
+// to create a contiguous, non-shared memory region instead.
+//
+if (PrintMiscellaneous && Verbose) {
+warning("Reverting to non-shared PerfMemory region.\n");
+}
+PerfDisableSharedMem = true;
+_start = create_standard_memory(size);
+}
+}
+if (_start != NULL) _capacity = size;
+}
+// delete the PerfData memory region
+//
+// This method deletes the memory region used to store performance
+// data for the JVM. The memory region indicated by the <address, size>
+// tuple will be inaccessible after a call to this method.
+//
+void PerfMemory::delete_memory_region() {
+assert((start() != NULL && capacity() > 0), "verify proper state");
+// If user specifies PerfDataSaveFile, it will save the performance data
+// to the specified file name no matter whether PerfDataSaveToFile is specified
+// or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
+// -XX:+PerfDataSaveToFile.
+if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
+save_memory_to_file(start(), capacity());
+}
+if (PerfDisableSharedMem) {
+delete_standard_memory(start(), capacity());
+}
+else {
+delete_shared_memory(start(), capacity());
+}
+}
+// attach to the PerfData memory region for another JVM
+//
+// This method returns an <address, size> tuple that points to
+// a memory buffer that is kept reasonably synchronized with
+// the PerfData memory region for the indicated JVM. This
+// buffer may be kept in synchronization via shared memory
+// or some other mechanism that keeps the buffer updated.
+//
+// If the JVM chooses not to support the attachability feature,
+// this method should throw an UnsupportedOperation exception.
+//
+// This implementation utilizes named shared memory to map
+// the indicated process's PerfData memory region into this JVMs
+// address space.
+//
+void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, char** addrp, size_t* sizep, TRAPS) {
+if (vmid == 0 || vmid == os::current_process_id()) {
+*addrp = start();
+*sizep = capacity();
+return;
+}
+mmap_attach_shared(user, vmid, mode, addrp, sizep, CHECK);
+}
+// detach from the PerfData memory region of another JVM
+//
+// This method detaches the PerfData memory region of another
+// JVM, specified as an <address, size> tuple of a buffer
+// in this process's address space. This method may perform
+// arbitrary actions to accomplish the detachment. The memory
+// region specified by <address, size> will be inaccessible after
+// a call to this method.
+//
+// If the JVM chooses not to support the attachability feature,
+// this method should throw an UnsupportedOperation exception.
+//
+// This implementation utilizes named shared memory to detach
+// the indicated process's PerfData memory region from this
+// process's address space.
+//
+void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
+assert(addr != 0, "address sanity check");
+assert(bytes > 0, "capacity sanity check");
+if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
+// prevent accidental detachment of this process's PerfMemory region
+return;
+}
+unmap_shared(addr, bytes);
+}
+char* PerfMemory::backing_store_filename() {
+return backing_store_file_name;
+}

Mercurial > hg > truffle

comparison src/os/linux/vm/perfMemory_linux.cpp @ 0:a61af66fc99e jdk7-b24