--- old/src/hotspot/os/solaris/perfMemory_solaris.cpp 2020-05-01 02:29:40.096353876 -0700 +++ /dev/null 2020-03-09 18:57:19.455001459 -0700 @@ -1,1294 +0,0 @@ -/* - * Copyright (c) 2001, 2019, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA - * or visit www.oracle.com if you need additional information or have any - * questions. - * - */ - -#include "precompiled.hpp" -#include "classfile/vmSymbols.hpp" -#include "logging/log.hpp" -#include "memory/allocation.inline.hpp" -#include "memory/resourceArea.hpp" -#include "oops/oop.inline.hpp" -#include "os_solaris.inline.hpp" -#include "runtime/handles.inline.hpp" -#include "runtime/perfMemory.hpp" -#include "services/memTracker.hpp" -#include "utilities/exceptions.hpp" - -// put OS-includes here -#include -#include -#include -#include -#include -#include -#include -#include - -/* For POSIX-compliant getpwuid_r on Solaris */ -#define _POSIX_PTHREAD_SEMANTICS -#include - -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, !ExecMem)) { - 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, os::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, os::strerror(errno)); - } - break; - } - remaining -= (size_t)result; - addr += result; - } - - result = ::close(fd); - if (PrintMiscellaneous && Verbose) { - if (result == OS_ERR) { - warning("Could not close %s: %s\n", destfile, os::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) + 3; - char* dirname = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal); - - // 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 statbuf is considered a secure directory for -// the backing store files. Returns true if the directory is considered -// a secure location. Returns false if the statbuf is a symbolic link or -// if an error occurred. -// -static bool is_statbuf_secure(struct stat *statp) { - if (S_ISLNK(statp->st_mode) || !S_ISDIR(statp->st_mode)) { - // The path represents a link or some non-directory file type, - // which is not what we expected. Declare it insecure. - // - return false; - } - // We have an existing directory, check if the permissions are safe. - // - if ((statp->st_mode & (S_IWGRP|S_IWOTH)) != 0) { - // The directory is open for writing and could be subjected - // to a symlink or a hard link attack. Declare it insecure. - // - return false; - } - // If user is not root then see if the uid of the directory matches the effective uid of the process. - uid_t euid = geteuid(); - if ((euid != 0) && (statp->st_uid != euid)) { - // The directory was not created by this user, declare it insecure. - // - return false; - } - return true; -} - - -// 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 occurred. -// -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, see if it is secure. - return is_statbuf_secure(&statbuf); -} - - -// Check if the given directory file descriptor 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 occurred. -// -static bool is_dirfd_secure(int dir_fd) { - struct stat statbuf; - int result = 0; - - RESTARTABLE(::fstat(dir_fd, &statbuf), result); - if (result == OS_ERR) { - return false; - } - - // The path exists, now check its mode. - return is_statbuf_secure(&statbuf); -} - - -// Check to make sure fd1 and fd2 are referencing the same file system object. -// -static bool is_same_fsobject(int fd1, int fd2) { - struct stat statbuf1; - struct stat statbuf2; - int result = 0; - - RESTARTABLE(::fstat(fd1, &statbuf1), result); - if (result == OS_ERR) { - return false; - } - RESTARTABLE(::fstat(fd2, &statbuf2), result); - if (result == OS_ERR) { - return false; - } - - if ((statbuf1.st_ino == statbuf2.st_ino) && - (statbuf1.st_dev == statbuf2.st_dev)) { - return true; - } else { - return false; - } -} - - -// Open the directory of the given path and validate it. -// Return a DIR * of the open directory. -// -static DIR *open_directory_secure(const char* dirname) { - // Open the directory using open() so that it can be verified - // to be secure by calling is_dirfd_secure(), opendir() and then check - // to see if they are the same file system object. This method does not - // introduce a window of opportunity for the directory to be attacked that - // calling opendir() and is_directory_secure() does. - int result; - DIR *dirp = NULL; - RESTARTABLE(::open(dirname, O_RDONLY|O_NOFOLLOW), result); - if (result == OS_ERR) { - // Directory doesn't exist or is a symlink, so there is nothing to cleanup. - if (PrintMiscellaneous && Verbose) { - if (errno == ELOOP) { - warning("directory %s is a symlink and is not secure\n", dirname); - } else { - warning("could not open directory %s: %s\n", dirname, os::strerror(errno)); - } - } - return dirp; - } - int fd = result; - - // Determine if the open directory is secure. - if (!is_dirfd_secure(fd)) { - // The directory is not a secure directory. - os::close(fd); - return dirp; - } - - // Open the directory. - dirp = ::opendir(dirname); - if (dirp == NULL) { - // The directory doesn't exist, close fd and return. - os::close(fd); - return dirp; - } - - // Check to make sure fd and dirp are referencing the same file system object. - if (!is_same_fsobject(fd, dirp->d_fd)) { - // The directory is not secure. - os::close(fd); - os::closedir(dirp); - dirp = NULL; - return dirp; - } - - // Close initial open now that we know directory is secure - os::close(fd); - - return dirp; -} - -// NOTE: The code below uses fchdir(), open() and unlink() because -// fdopendir(), openat() and unlinkat() are not supported on all -// versions. Once the support for fdopendir(), openat() and unlinkat() -// is available on all supported versions the code can be changed -// to use these functions. - -// Open the directory of the given path, validate it and set the -// current working directory to it. -// Return a DIR * of the open directory and the saved cwd fd. -// -static DIR *open_directory_secure_cwd(const char* dirname, int *saved_cwd_fd) { - - // Open the directory. - DIR* dirp = open_directory_secure(dirname); - if (dirp == NULL) { - // Directory doesn't exist or is insecure, so there is nothing to cleanup. - return dirp; - } - int fd = dirp->d_fd; - - // Open a fd to the cwd and save it off. - int result; - RESTARTABLE(::open(".", O_RDONLY), result); - if (result == OS_ERR) { - *saved_cwd_fd = -1; - } else { - *saved_cwd_fd = result; - } - - // Set the current directory to dirname by using the fd of the directory and - // handle errors, otherwise shared memory files will be created in cwd. - result = fchdir(fd); - if (result == OS_ERR) { - if (PrintMiscellaneous && Verbose) { - warning("could not change to directory %s", dirname); - } - if (*saved_cwd_fd != -1) { - ::close(*saved_cwd_fd); - *saved_cwd_fd = -1; - } - // Close the directory. - os::closedir(dirp); - return NULL; - } else { - return dirp; - } -} - -// Close the directory and restore the current working directory. -// -static void close_directory_secure_cwd(DIR* dirp, int saved_cwd_fd) { - - int result; - // If we have a saved cwd change back to it and close the fd. - if (saved_cwd_fd != -1) { - result = fchdir(saved_cwd_fd); - ::close(saved_cwd_fd); - } - - // Close the directory. - os::closedir(dirp); -} - -// Check if the given file descriptor is considered a secure. -// -static bool is_file_secure(int fd, const char *filename) { - - int result; - struct stat statbuf; - - // Determine if the file is secure. - RESTARTABLE(::fstat(fd, &statbuf), result); - if (result == OS_ERR) { - if (PrintMiscellaneous && Verbose) { - warning("fstat failed on %s: %s\n", filename, os::strerror(errno)); - } - return false; - } - if (statbuf.st_nlink > 1) { - // A file with multiple links is not expected. - if (PrintMiscellaneous && Verbose) { - warning("file %s has multiple links\n", filename); - } - 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, mtInternal); - - struct passwd* p = NULL; - int result = getpwuid_r(uid, &pwent, pwbuf, (size_t)bufsize, &p); - - if (p == NULL || p->pw_name == NULL || *(p->pw_name) == '\0') { - if (PrintMiscellaneous && Verbose) { - if (p == NULL) { - warning("Could not retrieve passwd entry: %s\n", - os::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, mtInternal); - 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_ 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(), os::strerror(errno)); - } - } - - // directory search - char* oldest_user = NULL; - time_t oldest_ctime = 0; - - const char* tmpdirname = os::get_temp_directory(); - - // open the temp directory - DIR* tmpdirp = os::opendir(tmpdirname); - - if (tmpdirp == NULL) { - // Cannot open the directory to get the user name, return. - 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; - errno = 0; - while ((dentry = os::readdir(tmpdirp)) != 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) + 2, mtInternal); - strcpy(usrdir_name, tmpdirname); - strcat(usrdir_name, "/"); - strcat(usrdir_name, dentry->d_name); - - // open the user directory - DIR* subdirp = open_directory_secure(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; - errno = 0; - while ((udentry = os::readdir(subdirp)) != 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, mtInternal); - - 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; - - FREE_C_HEAP_ARRAY(char, oldest_user); - oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal); - - strcpy(oldest_user, user); - oldest_ctime = statbuf.st_ctime; - } - } - - FREE_C_HEAP_ARRAY(char, filename); - } - } - os::closedir(subdirp); - FREE_C_HEAP_ARRAY(char, usrdir_name); - } - os::closedir(tmpdirp); - - 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) { - - char psinfo_name[PATH_MAX]; - int result; - - snprintf(psinfo_name, PATH_MAX, "/proc/%d/psinfo", vmid); - - RESTARTABLE(::open(psinfo_name, O_RDONLY), result); - - if (result != OS_ERR) { - int fd = result; - - psinfo_t psinfo; - char* addr = (char*)&psinfo; - - for (size_t remaining = sizeof(psinfo_t); remaining > 0;) { - - RESTARTABLE(::read(fd, addr, remaining), result); - if (result == OS_ERR) { - ::close(fd); - THROW_MSG_0(vmSymbols::java_io_IOException(), "Read error"); - } else { - remaining-=result; - addr+=result; - } - } - - ::close(fd); - - // get the user name for the effective user id of the process - char* user_name = get_user_name(psinfo.pr_euid); - - return user_name; - } - - if (result == OS_ERR && errno == EACCES) { - - // In this case, the psinfo file for the process id existed, - // but we didn't have permission to access it. - THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), - os::strerror(errno)); - } - - // at this point, we don't know if the process id itself doesn't - // exist or if the psinfo file doesn't exit. If the psinfo file - // doesn't exist, then we are running on Solaris 2.5.1 or earlier. - // since the structured procfs and old procfs interfaces can't be - // mixed, we attempt to find the file through a directory search. - - return get_user_name_slow(vmid, THREAD); -} - -// 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, mtInternal); - 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, os::strerror(errno)); - } - } -} - - -// 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) { - - int saved_cwd_fd; - // open the directory - DIR* dirp = open_directory_secure_cwd(dirname, &saved_cwd_fd); - if (dirp == NULL) { - // directory doesn't exist or is insecure, so there is nothing to cleanup - 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; - errno = 0; - while ((entry = os::readdir(dirp)) != 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 ".." - unlink(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))) { - - unlink(entry->d_name); - } - errno = 0; - } - - // close the directory and reset the current working directory - close_directory_secure_cwd(dirp, saved_cwd_fd); -} - -// 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, os::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 saved_cwd_fd; - // open the directory and set the current working directory to it - DIR* dirp = open_directory_secure_cwd(dirname, &saved_cwd_fd); - if (dirp == NULL) { - // Directory doesn't exist or is insecure, so cannot create shared - // memory file. - return -1; - } - - // Open the filename in the current directory. - // Cannot use O_TRUNC here; truncation of an existing file has to happen - // after the is_file_secure() check below. - int result; - RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_NOFOLLOW, S_IREAD|S_IWRITE), result); - if (result == OS_ERR) { - if (PrintMiscellaneous && Verbose) { - if (errno == ELOOP) { - warning("file %s is a symlink and is not secure\n", filename); - } else { - warning("could not create file %s: %s\n", filename, os::strerror(errno)); - } - } - // close the directory and reset the current working directory - close_directory_secure_cwd(dirp, saved_cwd_fd); - - return -1; - } - // close the directory and reset the current working directory - close_directory_secure_cwd(dirp, saved_cwd_fd); - - // save the file descriptor - int fd = result; - - // check to see if the file is secure - if (!is_file_secure(fd, filename)) { - ::close(fd); - return -1; - } - - // truncate the file to get rid of any existing data - RESTARTABLE(::ftruncate(fd, (off_t)0), result); - if (result == OS_ERR) { - if (PrintMiscellaneous && Verbose) { - warning("could not truncate shared memory file: %s\n", os::strerror(errno)); - } - ::close(fd); - return -1; - } - // 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", os::strerror(errno)); - } - ::close(fd); - 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_(vmSymbols::java_lang_IllegalArgumentException(), - "Process not found", OS_ERR); - } - else if (errno == EACCES) { - THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(), - "Permission denied", OS_ERR); - } - else { - THROW_MSG_(vmSymbols::java_io_IOException(), - os::strerror(errno), OS_ERR); - } - } - int fd = result; - - // check to see if the file is secure - if (!is_file_secure(fd, filename)) { - ::close(fd); - return -1; - } - - return fd; -} - -// 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, 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); - - // get the short filename - char* short_filename = strrchr(filename, '/'); - if (short_filename == NULL) { - short_filename = filename; - } else { - short_filename++; - } - - // 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, short_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); - - result = ::close(fd); - assert(result != OS_ERR, "could not close file"); - - if (mapAddress == MAP_FAILED) { - if (PrintMiscellaneous && Verbose) { - warning("mmap failed - %s\n", os::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); - - // it does not go through os api, the operation has to record from here - MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress, - size, CURRENT_PC, mtInternal); - - 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", os::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_io_IOException(), - "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 = 0; - 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 | O_NOFOLLOW; - } - else if (mode == PerfMemory::PERF_MODE_RW) { -#ifdef LATER - mmap_prot = PROT_READ | PROT_WRITE; - file_flags = O_RDWR | O_NOFOLLOW; -#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); - if (luser != user) { - FREE_C_HEAP_ARRAY(char, luser); - } - 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, THREAD); - - if (fd == OS_ERR) { - return; - } - - if (HAS_PENDING_EXCEPTION) { - ::close(fd); - return; - } - - if (*sizep == 0) { - size = sharedmem_filesize(fd, CHECK); - } else { - size = *sizep; - } - - assert(size > 0, "unexpected size <= 0"); - - mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0); - - result = ::close(fd); - assert(result != OS_ERR, "could not close file"); - - if (mapAddress == MAP_FAILED) { - if (PrintMiscellaneous && Verbose) { - warning("mmap failed: %s\n", os::strerror(errno)); - } - THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(), - "Could not map PerfMemory"); - } - - // it does not go through os api, the operation has to record from here - MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress, - size, CURRENT_PC, mtInternal); - - *addr = mapAddress; - *sizep = size; - - log_debug(perf, memops)("mapped " SIZE_FORMAT " bytes for vmid %d at " - INTPTR_FORMAT, 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 -// 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 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 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 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); -}