duke@435: /*
dcubed@6414:  * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #include "precompiled.hpp"
stefank@2314: #include "classfile/vmSymbols.hpp"
stefank@2314: #include "memory/allocation.inline.hpp"
stefank@2314: #include "memory/resourceArea.hpp"
stefank@2314: #include "oops/oop.inline.hpp"
stefank@2314: #include "os_linux.inline.hpp"
stefank@2314: #include "runtime/handles.inline.hpp"
stefank@2314: #include "runtime/perfMemory.hpp"
zgu@4193: #include "services/memTracker.hpp"
stefank@2314: #include "utilities/exceptions.hpp"
duke@435: 
duke@435: // put OS-includes here
duke@435: # include <sys/types.h>
duke@435: # include <sys/mman.h>
duke@435: # include <errno.h>
duke@435: # include <stdio.h>
duke@435: # include <unistd.h>
duke@435: # include <sys/stat.h>
duke@435: # include <signal.h>
duke@435: # include <pwd.h>
duke@435: 
duke@435: static char* backing_store_file_name = NULL;  // name of the backing store
duke@435:                                               // file, if successfully created.
duke@435: 
duke@435: // Standard Memory Implementation Details
duke@435: 
duke@435: // create the PerfData memory region in standard memory.
duke@435: //
duke@435: static char* create_standard_memory(size_t size) {
duke@435: 
duke@435:   // allocate an aligned chuck of memory
duke@435:   char* mapAddress = os::reserve_memory(size);
duke@435: 
duke@435:   if (mapAddress == NULL) {
duke@435:     return NULL;
duke@435:   }
duke@435: 
duke@435:   // commit memory
dcubed@5255:   if (!os::commit_memory(mapAddress, size, !ExecMem)) {
duke@435:     if (PrintMiscellaneous && Verbose) {
duke@435:       warning("Could not commit PerfData memory\n");
duke@435:     }
duke@435:     os::release_memory(mapAddress, size);
duke@435:     return NULL;
duke@435:   }
duke@435: 
duke@435:   return mapAddress;
duke@435: }
duke@435: 
duke@435: // delete the PerfData memory region
duke@435: //
duke@435: static void delete_standard_memory(char* addr, size_t size) {
duke@435: 
duke@435:   // there are no persistent external resources to cleanup for standard
duke@435:   // memory. since DestroyJavaVM does not support unloading of the JVM,
duke@435:   // cleanup of the memory resource is not performed. The memory will be
duke@435:   // reclaimed by the OS upon termination of the process.
duke@435:   //
duke@435:   return;
duke@435: }
duke@435: 
duke@435: // save the specified memory region to the given file
duke@435: //
duke@435: // Note: this function might be called from signal handler (by os::abort()),
duke@435: // don't allocate heap memory.
duke@435: //
duke@435: static void save_memory_to_file(char* addr, size_t size) {
duke@435: 
duke@435:  const char* destfile = PerfMemory::get_perfdata_file_path();
duke@435:  assert(destfile[0] != '\0', "invalid PerfData file path");
duke@435: 
duke@435:   int result;
duke@435: 
duke@435:   RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE),
duke@435:               result);;
duke@435:   if (result == OS_ERR) {
duke@435:     if (PrintMiscellaneous && Verbose) {
duke@435:       warning("Could not create Perfdata save file: %s: %s\n",
duke@435:               destfile, strerror(errno));
duke@435:     }
duke@435:   } else {
duke@435:     int fd = result;
duke@435: 
duke@435:     for (size_t remaining = size; remaining > 0;) {
duke@435: 
duke@435:       RESTARTABLE(::write(fd, addr, remaining), result);
duke@435:       if (result == OS_ERR) {
duke@435:         if (PrintMiscellaneous && Verbose) {
duke@435:           warning("Could not write Perfdata save file: %s: %s\n",
duke@435:                   destfile, strerror(errno));
duke@435:         }
duke@435:         break;
duke@435:       }
duke@435: 
duke@435:       remaining -= (size_t)result;
duke@435:       addr += result;
duke@435:     }
duke@435: 
rdurbin@5264:     result = ::close(fd);
duke@435:     if (PrintMiscellaneous && Verbose) {
duke@435:       if (result == OS_ERR) {
duke@435:         warning("Could not close %s: %s\n", destfile, strerror(errno));
duke@435:       }
duke@435:     }
duke@435:   }
zgu@3900:   FREE_C_HEAP_ARRAY(char, destfile, mtInternal);
duke@435: }
duke@435: 
duke@435: 
duke@435: // Shared Memory Implementation Details
duke@435: 
duke@435: // Note: the solaris and linux shared memory implementation uses the mmap
duke@435: // interface with a backing store file to implement named shared memory.
duke@435: // Using the file system as the name space for shared memory allows a
duke@435: // common name space to be supported across a variety of platforms. It
duke@435: // also provides a name space that Java applications can deal with through
duke@435: // simple file apis.
duke@435: //
duke@435: // The solaris and linux implementations store the backing store file in
duke@435: // a user specific temporary directory located in the /tmp file system,
duke@435: // which is always a local file system and is sometimes a RAM based file
duke@435: // system.
duke@435: 
duke@435: // return the user specific temporary directory name.
duke@435: //
duke@435: // the caller is expected to free the allocated memory.
duke@435: //
duke@435: static char* get_user_tmp_dir(const char* user) {
duke@435: 
duke@435:   const char* tmpdir = os::get_temp_directory();
duke@435:   const char* perfdir = PERFDATA_NAME;
coleenp@1788:   size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3;
zgu@3900:   char* dirname = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
duke@435: 
duke@435:   // construct the path name to user specific tmp directory
coleenp@1788:   snprintf(dirname, nbytes, "%s/%s_%s", tmpdir, perfdir, user);
duke@435: 
duke@435:   return dirname;
duke@435: }
duke@435: 
duke@435: // convert the given file name into a process id. if the file
duke@435: // does not meet the file naming constraints, return 0.
duke@435: //
duke@435: static pid_t filename_to_pid(const char* filename) {
duke@435: 
duke@435:   // a filename that doesn't begin with a digit is not a
duke@435:   // candidate for conversion.
duke@435:   //
duke@435:   if (!isdigit(*filename)) {
duke@435:     return 0;
duke@435:   }
duke@435: 
duke@435:   // check if file name can be converted to an integer without
duke@435:   // any leftover characters.
duke@435:   //
duke@435:   char* remainder = NULL;
duke@435:   errno = 0;
duke@435:   pid_t pid = (pid_t)strtol(filename, &remainder, 10);
duke@435: 
duke@435:   if (errno != 0) {
duke@435:     return 0;
duke@435:   }
duke@435: 
duke@435:   // check for left over characters. If any, then the filename is
duke@435:   // not a candidate for conversion.
duke@435:   //
duke@435:   if (remainder != NULL && *remainder != '\0') {
duke@435:     return 0;
duke@435:   }
duke@435: 
duke@435:   // successful conversion, return the pid
duke@435:   return pid;
duke@435: }
duke@435: 
duke@435: 
gthornbr@7493: // Check if the given statbuf is considered a secure directory for
gthornbr@7493: // the backing store files. Returns true if the directory is considered
gthornbr@7493: // a secure location. Returns false if the statbuf is a symbolic link or
gthornbr@7493: // if an error occurred.
gthornbr@7493: //
gthornbr@7493: static bool is_statbuf_secure(struct stat *statp) {
gthornbr@7493:   if (S_ISLNK(statp->st_mode) || !S_ISDIR(statp->st_mode)) {
gthornbr@7493:     // The path represents a link or some non-directory file type,
gthornbr@7493:     // which is not what we expected. Declare it insecure.
gthornbr@7493:     //
gthornbr@7493:     return false;
gthornbr@7493:   }
gthornbr@7493:   // We have an existing directory, check if the permissions are safe.
gthornbr@7493:   //
gthornbr@7493:   if ((statp->st_mode & (S_IWGRP|S_IWOTH)) != 0) {
gthornbr@7493:     // The directory is open for writing and could be subjected
gthornbr@7493:     // to a symlink or a hard link attack. Declare it insecure.
gthornbr@7493:     //
gthornbr@7493:     return false;
gthornbr@7493:   }
gthornbr@7493:   // See if the uid of the directory matches the effective uid of the process.
gthornbr@7493:   //
gthornbr@7493:   if (statp->st_uid != geteuid()) {
gthornbr@7493:     // The directory was not created by this user, declare it insecure.
gthornbr@7493:     //
gthornbr@7493:     return false;
gthornbr@7493:   }
gthornbr@7493:   return true;
gthornbr@7493: }
gthornbr@7493: 
gthornbr@7493: 
gthornbr@7493: // Check if the given path is considered a secure directory for
duke@435: // the backing store files. Returns true if the directory exists
duke@435: // and is considered a secure location. Returns false if the path
twisti@1040: // is a symbolic link or if an error occurred.
duke@435: //
duke@435: static bool is_directory_secure(const char* path) {
duke@435:   struct stat statbuf;
duke@435:   int result = 0;
duke@435: 
duke@435:   RESTARTABLE(::lstat(path, &statbuf), result);
duke@435:   if (result == OS_ERR) {
duke@435:     return false;
duke@435:   }
duke@435: 
gthornbr@7493:   // The path exists, see if it is secure.
gthornbr@7493:   return is_statbuf_secure(&statbuf);
gthornbr@7493: }
gthornbr@7493: 
gthornbr@7493: 
gthornbr@7493: // Check if the given directory file descriptor is considered a secure
gthornbr@7493: // directory for the backing store files. Returns true if the directory
gthornbr@7493: // exists and is considered a secure location. Returns false if the path
gthornbr@7493: // is a symbolic link or if an error occurred.
gthornbr@7493: //
gthornbr@7493: static bool is_dirfd_secure(int dir_fd) {
gthornbr@7493:   struct stat statbuf;
gthornbr@7493:   int result = 0;
gthornbr@7493: 
gthornbr@7493:   RESTARTABLE(::fstat(dir_fd, &statbuf), result);
gthornbr@7493:   if (result == OS_ERR) {
duke@435:     return false;
duke@435:   }
gthornbr@7493: 
gthornbr@7493:   // The path exists, now check its mode.
gthornbr@7493:   return is_statbuf_secure(&statbuf);
gthornbr@7493: }
gthornbr@7493: 
gthornbr@7493: 
gthornbr@7493: // Check to make sure fd1 and fd2 are referencing the same file system object.
gthornbr@7493: //
gthornbr@7493: static bool is_same_fsobject(int fd1, int fd2) {
gthornbr@7493:   struct stat statbuf1;
gthornbr@7493:   struct stat statbuf2;
gthornbr@7493:   int result = 0;
gthornbr@7493: 
gthornbr@7493:   RESTARTABLE(::fstat(fd1, &statbuf1), result);
gthornbr@7493:   if (result == OS_ERR) {
gthornbr@7493:     return false;
gthornbr@7493:   }
gthornbr@7493:   RESTARTABLE(::fstat(fd2, &statbuf2), result);
gthornbr@7493:   if (result == OS_ERR) {
gthornbr@7493:     return false;
gthornbr@7493:   }
gthornbr@7493: 
gthornbr@7493:   if ((statbuf1.st_ino == statbuf2.st_ino) &&
gthornbr@7493:       (statbuf1.st_dev == statbuf2.st_dev)) {
gthornbr@7493:     return true;
gthornbr@7493:   } else {
gthornbr@7493:     return false;
gthornbr@7493:   }
gthornbr@7493: }
gthornbr@7493: 
gthornbr@7493: 
gthornbr@7493: // Open the directory of the given path and validate it.
gthornbr@7493: // Return a DIR * of the open directory.
gthornbr@7493: //
gthornbr@7493: static DIR *open_directory_secure(const char* dirname) {
gthornbr@7493:   // Open the directory using open() so that it can be verified
gthornbr@7493:   // to be secure by calling is_dirfd_secure(), opendir() and then check
gthornbr@7493:   // to see if they are the same file system object.  This method does not
gthornbr@7493:   // introduce a window of opportunity for the directory to be attacked that
gthornbr@7493:   // calling opendir() and is_directory_secure() does.
gthornbr@7493:   int result;
gthornbr@7493:   DIR *dirp = NULL;
gthornbr@7493:   RESTARTABLE(::open(dirname, O_RDONLY|O_NOFOLLOW), result);
gthornbr@7493:   if (result == OS_ERR) {
gthornbr@7493:     if (PrintMiscellaneous && Verbose) {
gthornbr@7493:       if (errno == ELOOP) {
gthornbr@7493:         warning("directory %s is a symlink and is not secure\n", dirname);
gthornbr@7493:       } else {
gthornbr@7493:         warning("could not open directory %s: %s\n", dirname, strerror(errno));
gthornbr@7493:       }
duke@435:     }
gthornbr@7493:     return dirp;
gthornbr@7493:   }
gthornbr@7493:   int fd = result;
gthornbr@7493: 
gthornbr@7493:   // Determine if the open directory is secure.
gthornbr@7493:   if (!is_dirfd_secure(fd)) {
gthornbr@7493:     // The directory is not a secure directory.
gthornbr@7493:     os::close(fd);
gthornbr@7493:     return dirp;
gthornbr@7493:   }
gthornbr@7493: 
gthornbr@7493:   // Open the directory.
gthornbr@7493:   dirp = ::opendir(dirname);
gthornbr@7493:   if (dirp == NULL) {
gthornbr@7493:     // The directory doesn't exist, close fd and return.
gthornbr@7493:     os::close(fd);
gthornbr@7493:     return dirp;
gthornbr@7493:   }
gthornbr@7493: 
gthornbr@7493:   // Check to make sure fd and dirp are referencing the same file system object.
gthornbr@7493:   if (!is_same_fsobject(fd, dirfd(dirp))) {
gthornbr@7493:     // The directory is not secure.
gthornbr@7493:     os::close(fd);
gthornbr@7493:     os::closedir(dirp);
gthornbr@7493:     dirp = NULL;
gthornbr@7493:     return dirp;
gthornbr@7493:   }
gthornbr@7493: 
gthornbr@7493:   // Close initial open now that we know directory is secure
gthornbr@7493:   os::close(fd);
gthornbr@7493: 
gthornbr@7493:   return dirp;
gthornbr@7493: }
gthornbr@7493: 
gthornbr@7493: // NOTE: The code below uses fchdir(), open() and unlink() because
gthornbr@7493: // fdopendir(), openat() and unlinkat() are not supported on all
gthornbr@7493: // versions.  Once the support for fdopendir(), openat() and unlinkat()
gthornbr@7493: // is available on all supported versions the code can be changed
gthornbr@7493: // to use these functions.
gthornbr@7493: 
gthornbr@7493: // Open the directory of the given path, validate it and set the
gthornbr@7493: // current working directory to it.
gthornbr@7493: // Return a DIR * of the open directory and the saved cwd fd.
gthornbr@7493: //
gthornbr@7493: static DIR *open_directory_secure_cwd(const char* dirname, int *saved_cwd_fd) {
gthornbr@7493: 
gthornbr@7493:   // Open the directory.
gthornbr@7493:   DIR* dirp = open_directory_secure(dirname);
gthornbr@7493:   if (dirp == NULL) {
gthornbr@7493:     // Directory doesn't exist or is insecure, so there is nothing to cleanup.
gthornbr@7493:     return dirp;
gthornbr@7493:   }
gthornbr@7493:   int fd = dirfd(dirp);
gthornbr@7493: 
gthornbr@7493:   // Open a fd to the cwd and save it off.
gthornbr@7493:   int result;
gthornbr@7493:   RESTARTABLE(::open(".", O_RDONLY), result);
gthornbr@7493:   if (result == OS_ERR) {
gthornbr@7493:     *saved_cwd_fd = -1;
gthornbr@7493:   } else {
gthornbr@7493:     *saved_cwd_fd = result;
gthornbr@7493:   }
gthornbr@7493: 
gthornbr@7493:   // Set the current directory to dirname by using the fd of the directory.
gthornbr@7493:   result = fchdir(fd);
gthornbr@7493: 
gthornbr@7493:   return dirp;
gthornbr@7493: }
gthornbr@7493: 
gthornbr@7493: // Close the directory and restore the current working directory.
gthornbr@7493: //
gthornbr@7493: static void close_directory_secure_cwd(DIR* dirp, int saved_cwd_fd) {
gthornbr@7493: 
gthornbr@7493:   int result;
gthornbr@7493:   // If we have a saved cwd change back to it and close the fd.
gthornbr@7493:   if (saved_cwd_fd != -1) {
gthornbr@7493:     result = fchdir(saved_cwd_fd);
gthornbr@7493:     ::close(saved_cwd_fd);
gthornbr@7493:   }
gthornbr@7493: 
gthornbr@7493:   // Close the directory.
gthornbr@7493:   os::closedir(dirp);
gthornbr@7493: }
gthornbr@7493: 
gthornbr@7493: // Check if the given file descriptor is considered a secure.
gthornbr@7493: //
gthornbr@7493: static bool is_file_secure(int fd, const char *filename) {
gthornbr@7493: 
gthornbr@7493:   int result;
gthornbr@7493:   struct stat statbuf;
gthornbr@7493: 
gthornbr@7493:   // Determine if the file is secure.
gthornbr@7493:   RESTARTABLE(::fstat(fd, &statbuf), result);
gthornbr@7493:   if (result == OS_ERR) {
gthornbr@7493:     if (PrintMiscellaneous && Verbose) {
gthornbr@7493:       warning("fstat failed on %s: %s\n", filename, strerror(errno));
gthornbr@7493:     }
gthornbr@7493:     return false;
gthornbr@7493:   }
gthornbr@7493:   if (statbuf.st_nlink > 1) {
gthornbr@7493:     // A file with multiple links is not expected.
gthornbr@7493:     if (PrintMiscellaneous && Verbose) {
gthornbr@7493:       warning("file %s has multiple links\n", filename);
gthornbr@7493:     }
gthornbr@7493:     return false;
duke@435:   }
duke@435:   return true;
duke@435: }
duke@435: 
duke@435: 
duke@435: // return the user name for the given user id
duke@435: //
duke@435: // the caller is expected to free the allocated memory.
duke@435: //
duke@435: static char* get_user_name(uid_t uid) {
duke@435: 
duke@435:   struct passwd pwent;
duke@435: 
duke@435:   // determine the max pwbuf size from sysconf, and hardcode
duke@435:   // a default if this not available through sysconf.
duke@435:   //
duke@435:   long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
duke@435:   if (bufsize == -1)
duke@435:     bufsize = 1024;
duke@435: 
zgu@3900:   char* pwbuf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
duke@435: 
duke@435:   // POSIX interface to getpwuid_r is used on LINUX
duke@435:   struct passwd* p;
duke@435:   int result = getpwuid_r(uid, &pwent, pwbuf, (size_t)bufsize, &p);
duke@435: 
duke@435:   if (result != 0 || p == NULL || p->pw_name == NULL || *(p->pw_name) == '\0') {
duke@435:     if (PrintMiscellaneous && Verbose) {
duke@435:       if (result != 0) {
duke@435:         warning("Could not retrieve passwd entry: %s\n",
duke@435:                 strerror(result));
duke@435:       }
duke@435:       else if (p == NULL) {
duke@435:         // this check is added to protect against an observed problem
duke@435:         // with getpwuid_r() on RedHat 9 where getpwuid_r returns 0,
duke@435:         // indicating success, but has p == NULL. This was observed when
duke@435:         // inserting a file descriptor exhaustion fault prior to the call
duke@435:         // getpwuid_r() call. In this case, error is set to the appropriate
duke@435:         // error condition, but this is undocumented behavior. This check
duke@435:         // is safe under any condition, but the use of errno in the output
duke@435:         // message may result in an erroneous message.
duke@435:         // Bug Id 89052 was opened with RedHat.
duke@435:         //
duke@435:         warning("Could not retrieve passwd entry: %s\n",
duke@435:                 strerror(errno));
duke@435:       }
duke@435:       else {
duke@435:         warning("Could not determine user name: %s\n",
duke@435:                 p->pw_name == NULL ? "pw_name = NULL" :
duke@435:                                      "pw_name zero length");
duke@435:       }
duke@435:     }
zgu@3900:     FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal);
duke@435:     return NULL;
duke@435:   }
duke@435: 
zgu@3900:   char* user_name = NEW_C_HEAP_ARRAY(char, strlen(p->pw_name) + 1, mtInternal);
duke@435:   strcpy(user_name, p->pw_name);
duke@435: 
zgu@3900:   FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal);
duke@435:   return user_name;
duke@435: }
duke@435: 
duke@435: // return the name of the user that owns the process identified by vmid.
duke@435: //
duke@435: // This method uses a slow directory search algorithm to find the backing
duke@435: // store file for the specified vmid and returns the user name, as determined
duke@435: // by the user name suffix of the hsperfdata_<username> directory name.
duke@435: //
duke@435: // the caller is expected to free the allocated memory.
duke@435: //
duke@435: static char* get_user_name_slow(int vmid, TRAPS) {
duke@435: 
duke@435:   // short circuit the directory search if the process doesn't even exist.
duke@435:   if (kill(vmid, 0) == OS_ERR) {
duke@435:     if (errno == ESRCH) {
duke@435:       THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
duke@435:                   "Process not found");
duke@435:     }
duke@435:     else /* EPERM */ {
duke@435:       THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   // directory search
duke@435:   char* oldest_user = NULL;
duke@435:   time_t oldest_ctime = 0;
duke@435: 
duke@435:   const char* tmpdirname = os::get_temp_directory();
duke@435: 
gthornbr@7493:   // open the temp directory
duke@435:   DIR* tmpdirp = os::opendir(tmpdirname);
duke@435: 
duke@435:   if (tmpdirp == NULL) {
gthornbr@7493:     // Cannot open the directory to get the user name, return.
duke@435:     return NULL;
duke@435:   }
duke@435: 
duke@435:   // for each entry in the directory that matches the pattern hsperfdata_*,
duke@435:   // open the directory and check if the file for the given vmid exists.
duke@435:   // The file with the expected name and the latest creation date is used
duke@435:   // to determine the user name for the process id.
duke@435:   //
duke@435:   struct dirent* dentry;
zgu@3900:   char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname), mtInternal);
duke@435:   errno = 0;
duke@435:   while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) {
duke@435: 
duke@435:     // check if the directory entry is a hsperfdata file
duke@435:     if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
duke@435:       continue;
duke@435:     }
duke@435: 
duke@435:     char* usrdir_name = NEW_C_HEAP_ARRAY(char,
zgu@3900:                      strlen(tmpdirname) + strlen(dentry->d_name) + 2, mtInternal);
duke@435:     strcpy(usrdir_name, tmpdirname);
coleenp@1788:     strcat(usrdir_name, "/");
duke@435:     strcat(usrdir_name, dentry->d_name);
duke@435: 
gthornbr@7493:     // open the user directory
gthornbr@7493:     DIR* subdirp = open_directory_secure(usrdir_name);
duke@435: 
duke@435:     if (subdirp == NULL) {
zgu@3900:       FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
duke@435:       continue;
duke@435:     }
duke@435: 
duke@435:     // Since we don't create the backing store files in directories
duke@435:     // pointed to by symbolic links, we also don't follow them when
duke@435:     // looking for the files. We check for a symbolic link after the
duke@435:     // call to opendir in order to eliminate a small window where the
duke@435:     // symlink can be exploited.
duke@435:     //
duke@435:     if (!is_directory_secure(usrdir_name)) {
zgu@3900:       FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
duke@435:       os::closedir(subdirp);
duke@435:       continue;
duke@435:     }
duke@435: 
duke@435:     struct dirent* udentry;
zgu@3900:     char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name), mtInternal);
duke@435:     errno = 0;
duke@435:     while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
duke@435: 
duke@435:       if (filename_to_pid(udentry->d_name) == vmid) {
duke@435:         struct stat statbuf;
duke@435:         int result;
duke@435: 
duke@435:         char* filename = NEW_C_HEAP_ARRAY(char,
zgu@3900:                    strlen(usrdir_name) + strlen(udentry->d_name) + 2, mtInternal);
duke@435: 
duke@435:         strcpy(filename, usrdir_name);
duke@435:         strcat(filename, "/");
duke@435:         strcat(filename, udentry->d_name);
duke@435: 
duke@435:         // don't follow symbolic links for the file
duke@435:         RESTARTABLE(::lstat(filename, &statbuf), result);
duke@435:         if (result == OS_ERR) {
zgu@3900:            FREE_C_HEAP_ARRAY(char, filename, mtInternal);
duke@435:            continue;
duke@435:         }
duke@435: 
duke@435:         // skip over files that are not regular files.
duke@435:         if (!S_ISREG(statbuf.st_mode)) {
zgu@3900:           FREE_C_HEAP_ARRAY(char, filename, mtInternal);
duke@435:           continue;
duke@435:         }
duke@435: 
duke@435:         // compare and save filename with latest creation time
duke@435:         if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) {
duke@435: 
duke@435:           if (statbuf.st_ctime > oldest_ctime) {
duke@435:             char* user = strchr(dentry->d_name, '_') + 1;
duke@435: 
zgu@3900:             if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user, mtInternal);
zgu@3900:             oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
duke@435: 
duke@435:             strcpy(oldest_user, user);
duke@435:             oldest_ctime = statbuf.st_ctime;
duke@435:           }
duke@435:         }
duke@435: 
zgu@3900:         FREE_C_HEAP_ARRAY(char, filename, mtInternal);
duke@435:       }
duke@435:     }
duke@435:     os::closedir(subdirp);
zgu@3900:     FREE_C_HEAP_ARRAY(char, udbuf, mtInternal);
zgu@3900:     FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
duke@435:   }
duke@435:   os::closedir(tmpdirp);
zgu@3900:   FREE_C_HEAP_ARRAY(char, tdbuf, mtInternal);
duke@435: 
duke@435:   return(oldest_user);
duke@435: }
duke@435: 
duke@435: // return the name of the user that owns the JVM indicated by the given vmid.
duke@435: //
duke@435: static char* get_user_name(int vmid, TRAPS) {
duke@435:   return get_user_name_slow(vmid, CHECK_NULL);
duke@435: }
duke@435: 
duke@435: // return the file name of the backing store file for the named
duke@435: // shared memory region for the given user name and vmid.
duke@435: //
duke@435: // the caller is expected to free the allocated memory.
duke@435: //
duke@435: static char* get_sharedmem_filename(const char* dirname, int vmid) {
duke@435: 
duke@435:   // add 2 for the file separator and a null terminator.
duke@435:   size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
duke@435: 
zgu@3900:   char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
duke@435:   snprintf(name, nbytes, "%s/%d", dirname, vmid);
duke@435: 
duke@435:   return name;
duke@435: }
duke@435: 
duke@435: 
duke@435: // remove file
duke@435: //
duke@435: // this method removes the file specified by the given path
duke@435: //
duke@435: static void remove_file(const char* path) {
duke@435: 
duke@435:   int result;
duke@435: 
duke@435:   // if the file is a directory, the following unlink will fail. since
duke@435:   // we don't expect to find directories in the user temp directory, we
duke@435:   // won't try to handle this situation. even if accidentially or
duke@435:   // maliciously planted, the directory's presence won't hurt anything.
duke@435:   //
duke@435:   RESTARTABLE(::unlink(path), result);
duke@435:   if (PrintMiscellaneous && Verbose && result == OS_ERR) {
duke@435:     if (errno != ENOENT) {
duke@435:       warning("Could not unlink shared memory backing"
duke@435:               " store file %s : %s\n", path, strerror(errno));
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
duke@435: 
duke@435: // cleanup stale shared memory resources
duke@435: //
duke@435: // This method attempts to remove all stale shared memory files in
duke@435: // the named user temporary directory. It scans the named directory
duke@435: // for files matching the pattern ^$[0-9]*$. For each file found, the
duke@435: // process id is extracted from the file name and a test is run to
duke@435: // determine if the process is alive. If the process is not alive,
duke@435: // any stale file resources are removed.
duke@435: //
duke@435: static void cleanup_sharedmem_resources(const char* dirname) {
duke@435: 
gthornbr@7493:   int saved_cwd_fd;
gthornbr@7493:   // open the directory
gthornbr@7493:   DIR* dirp = open_directory_secure_cwd(dirname, &saved_cwd_fd);
duke@435:   if (dirp == NULL) {
gthornbr@7493:     // directory doesn't exist or is insecure, so there is nothing to cleanup
duke@435:     return;
duke@435:   }
duke@435: 
duke@435:   // for each entry in the directory that matches the expected file
duke@435:   // name pattern, determine if the file resources are stale and if
duke@435:   // so, remove the file resources. Note, instrumented HotSpot processes
duke@435:   // for this user may start and/or terminate during this search and
duke@435:   // remove or create new files in this directory. The behavior of this
duke@435:   // loop under these conditions is dependent upon the implementation of
duke@435:   // opendir/readdir.
duke@435:   //
duke@435:   struct dirent* entry;
zgu@3900:   char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname), mtInternal);
gthornbr@7493: 
duke@435:   errno = 0;
duke@435:   while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) {
duke@435: 
duke@435:     pid_t pid = filename_to_pid(entry->d_name);
duke@435: 
duke@435:     if (pid == 0) {
duke@435: 
duke@435:       if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
duke@435:         // attempt to remove all unexpected files, except "." and ".."
gthornbr@7493:         unlink(entry->d_name);
duke@435:       }
duke@435: 
duke@435:       errno = 0;
duke@435:       continue;
duke@435:     }
duke@435: 
duke@435:     // we now have a file name that converts to a valid integer
duke@435:     // that could represent a process id . if this process id
duke@435:     // matches the current process id or the process is not running,
duke@435:     // then remove the stale file resources.
duke@435:     //
duke@435:     // process liveness is detected by sending signal number 0 to
duke@435:     // the process id (see kill(2)). if kill determines that the
duke@435:     // process does not exist, then the file resources are removed.
duke@435:     // if kill determines that that we don't have permission to
duke@435:     // signal the process, then the file resources are assumed to
duke@435:     // be stale and are removed because the resources for such a
duke@435:     // process should be in a different user specific directory.
duke@435:     //
duke@435:     if ((pid == os::current_process_id()) ||
duke@435:         (kill(pid, 0) == OS_ERR && (errno == ESRCH || errno == EPERM))) {
gthornbr@7493:         unlink(entry->d_name);
duke@435:     }
duke@435:     errno = 0;
duke@435:   }
gthornbr@7493: 
gthornbr@7493:   // close the directory and reset the current working directory
gthornbr@7493:   close_directory_secure_cwd(dirp, saved_cwd_fd);
gthornbr@7493: 
zgu@3900:   FREE_C_HEAP_ARRAY(char, dbuf, mtInternal);
duke@435: }
duke@435: 
duke@435: // make the user specific temporary directory. Returns true if
duke@435: // the directory exists and is secure upon return. Returns false
duke@435: // if the directory exists but is either a symlink, is otherwise
duke@435: // insecure, or if an error occurred.
duke@435: //
duke@435: static bool make_user_tmp_dir(const char* dirname) {
duke@435: 
duke@435:   // create the directory with 0755 permissions. note that the directory
duke@435:   // will be owned by euid::egid, which may not be the same as uid::gid.
duke@435:   //
duke@435:   if (mkdir(dirname, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) == OS_ERR) {
duke@435:     if (errno == EEXIST) {
duke@435:       // The directory already exists and was probably created by another
duke@435:       // JVM instance. However, this could also be the result of a
duke@435:       // deliberate symlink. Verify that the existing directory is safe.
duke@435:       //
duke@435:       if (!is_directory_secure(dirname)) {
duke@435:         // directory is not secure
duke@435:         if (PrintMiscellaneous && Verbose) {
duke@435:           warning("%s directory is insecure\n", dirname);
duke@435:         }
duke@435:         return false;
duke@435:       }
duke@435:     }
duke@435:     else {
duke@435:       // we encountered some other failure while attempting
duke@435:       // to create the directory
duke@435:       //
duke@435:       if (PrintMiscellaneous && Verbose) {
duke@435:         warning("could not create directory %s: %s\n",
duke@435:                 dirname, strerror(errno));
duke@435:       }
duke@435:       return false;
duke@435:     }
duke@435:   }
duke@435:   return true;
duke@435: }
duke@435: 
duke@435: // create the shared memory file resources
duke@435: //
duke@435: // This method creates the shared memory file with the given size
duke@435: // This method also creates the user specific temporary directory, if
duke@435: // it does not yet exist.
duke@435: //
duke@435: static int create_sharedmem_resources(const char* dirname, const char* filename, size_t size) {
duke@435: 
duke@435:   // make the user temporary directory
duke@435:   if (!make_user_tmp_dir(dirname)) {
duke@435:     // could not make/find the directory or the found directory
duke@435:     // was not secure
duke@435:     return -1;
duke@435:   }
duke@435: 
gthornbr@7493:   int saved_cwd_fd;
gthornbr@7493:   // open the directory and set the current working directory to it
gthornbr@7493:   DIR* dirp = open_directory_secure_cwd(dirname, &saved_cwd_fd);
gthornbr@7493:   if (dirp == NULL) {
gthornbr@7493:     // Directory doesn't exist or is insecure, so cannot create shared
gthornbr@7493:     // memory file.
gthornbr@7493:     return -1;
gthornbr@7493:   }
gthornbr@7493: 
gthornbr@7493:   // Open the filename in the current directory.
gthornbr@7493:   // Cannot use O_TRUNC here; truncation of an existing file has to happen
gthornbr@7493:   // after the is_file_secure() check below.
duke@435:   int result;
gthornbr@7493:   RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_NOFOLLOW, S_IREAD|S_IWRITE), result);
duke@435:   if (result == OS_ERR) {
duke@435:     if (PrintMiscellaneous && Verbose) {
gthornbr@7493:       if (errno == ELOOP) {
gthornbr@7493:         warning("file %s is a symlink and is not secure\n", filename);
gthornbr@7493:       } else {
gthornbr@7493:         warning("could not create file %s: %s\n", filename, strerror(errno));
gthornbr@7493:       }
duke@435:     }
gthornbr@7493:     // close the directory and reset the current working directory
gthornbr@7493:     close_directory_secure_cwd(dirp, saved_cwd_fd);
gthornbr@7493: 
duke@435:     return -1;
duke@435:   }
gthornbr@7493:   // close the directory and reset the current working directory
gthornbr@7493:   close_directory_secure_cwd(dirp, saved_cwd_fd);
duke@435: 
duke@435:   // save the file descriptor
duke@435:   int fd = result;
duke@435: 
gthornbr@7493:   // check to see if the file is secure
gthornbr@7493:   if (!is_file_secure(fd, filename)) {
gthornbr@7493:     ::close(fd);
gthornbr@7493:     return -1;
gthornbr@7493:   }
gthornbr@7493: 
gthornbr@7493:   // truncate the file to get rid of any existing data
gthornbr@7493:   RESTARTABLE(::ftruncate(fd, (off_t)0), result);
gthornbr@7493:   if (result == OS_ERR) {
gthornbr@7493:     if (PrintMiscellaneous && Verbose) {
gthornbr@7493:       warning("could not truncate shared memory file: %s\n", strerror(errno));
gthornbr@7493:     }
gthornbr@7493:     ::close(fd);
gthornbr@7493:     return -1;
gthornbr@7493:   }
duke@435:   // set the file size
duke@435:   RESTARTABLE(::ftruncate(fd, (off_t)size), result);
duke@435:   if (result == OS_ERR) {
duke@435:     if (PrintMiscellaneous && Verbose) {
duke@435:       warning("could not set shared memory file size: %s\n", strerror(errno));
duke@435:     }
rdurbin@5264:     ::close(fd);
duke@435:     return -1;
duke@435:   }
duke@435: 
bobv@2389:   // Verify that we have enough disk space for this file.
bobv@2389:   // We'll get random SIGBUS crashes on memory accesses if
bobv@2389:   // we don't.
bobv@2389: 
bobv@2389:   for (size_t seekpos = 0; seekpos < size; seekpos += os::vm_page_size()) {
bobv@2389:     int zero_int = 0;
bobv@2389:     result = (int)os::seek_to_file_offset(fd, (jlong)(seekpos));
bobv@2389:     if (result == -1 ) break;
bobv@2389:     RESTARTABLE(::write(fd, &zero_int, 1), result);
bobv@2389:     if (result != 1) {
bobv@2389:       if (errno == ENOSPC) {
bobv@2389:         warning("Insufficient space for shared memory file:\n   %s\nTry using the -Djava.io.tmpdir= option to select an alternate temp location.\n", filename);
bobv@2389:       }
bobv@2389:       break;
bobv@2389:     }
bobv@2389:   }
bobv@2389: 
bobv@2389:   if (result != -1) {
bobv@2389:     return fd;
bobv@2389:   } else {
rdurbin@5264:     ::close(fd);
bobv@2389:     return -1;
bobv@2389:   }
duke@435: }
duke@435: 
duke@435: // open the shared memory file for the given user and vmid. returns
duke@435: // the file descriptor for the open file or -1 if the file could not
duke@435: // be opened.
duke@435: //
duke@435: static int open_sharedmem_file(const char* filename, int oflags, TRAPS) {
duke@435: 
duke@435:   // open the file
duke@435:   int result;
duke@435:   RESTARTABLE(::open(filename, oflags), result);
duke@435:   if (result == OS_ERR) {
duke@435:     if (errno == ENOENT) {
ccheung@4893:       THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),
ccheung@4893:                   "Process not found", OS_ERR);
duke@435:     }
duke@435:     else if (errno == EACCES) {
ccheung@4893:       THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),
ccheung@4893:                   "Permission denied", OS_ERR);
duke@435:     }
duke@435:     else {
ccheung@4893:       THROW_MSG_(vmSymbols::java_io_IOException(), strerror(errno), OS_ERR);
duke@435:     }
duke@435:   }
gthornbr@7493:   int fd = result;
duke@435: 
gthornbr@7493:   // check to see if the file is secure
gthornbr@7493:   if (!is_file_secure(fd, filename)) {
gthornbr@7493:     ::close(fd);
gthornbr@7493:     return -1;
gthornbr@7493:   }
gthornbr@7493: 
gthornbr@7493:   return fd;
duke@435: }
duke@435: 
duke@435: // create a named shared memory region. returns the address of the
duke@435: // memory region on success or NULL on failure. A return value of
duke@435: // NULL will ultimately disable the shared memory feature.
duke@435: //
duke@435: // On Solaris and Linux, the name space for shared memory objects
duke@435: // is the file system name space.
duke@435: //
duke@435: // A monitoring application attaching to a JVM does not need to know
duke@435: // the file system name of the shared memory object. However, it may
duke@435: // be convenient for applications to discover the existence of newly
duke@435: // created and terminating JVMs by watching the file system name space
duke@435: // for files being created or removed.
duke@435: //
duke@435: static char* mmap_create_shared(size_t size) {
duke@435: 
duke@435:   int result;
duke@435:   int fd;
duke@435:   char* mapAddress;
duke@435: 
duke@435:   int vmid = os::current_process_id();
duke@435: 
duke@435:   char* user_name = get_user_name(geteuid());
duke@435: 
duke@435:   if (user_name == NULL)
duke@435:     return NULL;
duke@435: 
duke@435:   char* dirname = get_user_tmp_dir(user_name);
duke@435:   char* filename = get_sharedmem_filename(dirname, vmid);
gthornbr@7493:   // get the short filename
gthornbr@7493:   char* short_filename = strrchr(filename, '/');
gthornbr@7493:   if (short_filename == NULL) {
gthornbr@7493:     short_filename = filename;
gthornbr@7493:   } else {
gthornbr@7493:     short_filename++;
gthornbr@7493:   }
duke@435: 
duke@435:   // cleanup any stale shared memory files
duke@435:   cleanup_sharedmem_resources(dirname);
duke@435: 
duke@435:   assert(((size > 0) && (size % os::vm_page_size() == 0)),
duke@435:          "unexpected PerfMemory region size");
duke@435: 
gthornbr@7493:   fd = create_sharedmem_resources(dirname, short_filename, size);
duke@435: 
zgu@3900:   FREE_C_HEAP_ARRAY(char, user_name, mtInternal);
zgu@3900:   FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
duke@435: 
duke@435:   if (fd == -1) {
zgu@3900:     FREE_C_HEAP_ARRAY(char, filename, mtInternal);
duke@435:     return NULL;
duke@435:   }
duke@435: 
duke@435:   mapAddress = (char*)::mmap((char*)0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
duke@435: 
rdurbin@5264:   result = ::close(fd);
duke@435:   assert(result != OS_ERR, "could not close file");
duke@435: 
duke@435:   if (mapAddress == MAP_FAILED) {
duke@435:     if (PrintMiscellaneous && Verbose) {
duke@435:       warning("mmap failed -  %s\n", strerror(errno));
duke@435:     }
duke@435:     remove_file(filename);
zgu@3900:     FREE_C_HEAP_ARRAY(char, filename, mtInternal);
duke@435:     return NULL;
duke@435:   }
duke@435: 
duke@435:   // save the file name for use in delete_shared_memory()
duke@435:   backing_store_file_name = filename;
duke@435: 
duke@435:   // clear the shared memory region
duke@435:   (void)::memset((void*) mapAddress, 0, size);
duke@435: 
zgu@4193:   // it does not go through os api, the operation has to record from here
zgu@7074:   MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress, size, CURRENT_PC, mtInternal);
zgu@4193: 
duke@435:   return mapAddress;
duke@435: }
duke@435: 
duke@435: // release a named shared memory region
duke@435: //
duke@435: static void unmap_shared(char* addr, size_t bytes) {
duke@435:   os::release_memory(addr, bytes);
duke@435: }
duke@435: 
duke@435: // create the PerfData memory region in shared memory.
duke@435: //
duke@435: static char* create_shared_memory(size_t size) {
duke@435: 
duke@435:   // create the shared memory region.
duke@435:   return mmap_create_shared(size);
duke@435: }
duke@435: 
duke@435: // delete the shared PerfData memory region
duke@435: //
duke@435: static void delete_shared_memory(char* addr, size_t size) {
duke@435: 
duke@435:   // cleanup the persistent shared memory resources. since DestroyJavaVM does
duke@435:   // not support unloading of the JVM, unmapping of the memory resource is
duke@435:   // not performed. The memory will be reclaimed by the OS upon termination of
duke@435:   // the process. The backing store file is deleted from the file system.
duke@435: 
duke@435:   assert(!PerfDisableSharedMem, "shouldn't be here");
duke@435: 
duke@435:   if (backing_store_file_name != NULL) {
duke@435:     remove_file(backing_store_file_name);
duke@435:     // Don't.. Free heap memory could deadlock os::abort() if it is called
duke@435:     // from signal handler. OS will reclaim the heap memory.
duke@435:     // FREE_C_HEAP_ARRAY(char, backing_store_file_name);
duke@435:     backing_store_file_name = NULL;
duke@435:   }
duke@435: }
duke@435: 
duke@435: // return the size of the file for the given file descriptor
duke@435: // or 0 if it is not a valid size for a shared memory file
duke@435: //
duke@435: static size_t sharedmem_filesize(int fd, TRAPS) {
duke@435: 
duke@435:   struct stat statbuf;
duke@435:   int result;
duke@435: 
duke@435:   RESTARTABLE(::fstat(fd, &statbuf), result);
duke@435:   if (result == OS_ERR) {
duke@435:     if (PrintMiscellaneous && Verbose) {
duke@435:       warning("fstat failed: %s\n", strerror(errno));
duke@435:     }
duke@435:     THROW_MSG_0(vmSymbols::java_io_IOException(),
duke@435:                 "Could not determine PerfMemory size");
duke@435:   }
duke@435: 
duke@435:   if ((statbuf.st_size == 0) ||
duke@435:      ((size_t)statbuf.st_size % os::vm_page_size() != 0)) {
duke@435:     THROW_MSG_0(vmSymbols::java_lang_Exception(),
duke@435:                 "Invalid PerfMemory size");
duke@435:   }
duke@435: 
duke@435:   return (size_t)statbuf.st_size;
duke@435: }
duke@435: 
duke@435: // attach to a named shared memory region.
duke@435: //
duke@435: static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemoryMode mode, char** addr, size_t* sizep, TRAPS) {
duke@435: 
duke@435:   char* mapAddress;
duke@435:   int result;
duke@435:   int fd;
ccheung@4893:   size_t size = 0;
duke@435:   const char* luser = NULL;
duke@435: 
duke@435:   int mmap_prot;
duke@435:   int file_flags;
duke@435: 
duke@435:   ResourceMark rm;
duke@435: 
duke@435:   // map the high level access mode to the appropriate permission
duke@435:   // constructs for the file and the shared memory mapping.
duke@435:   if (mode == PerfMemory::PERF_MODE_RO) {
duke@435:     mmap_prot = PROT_READ;
gthornbr@7493:     file_flags = O_RDONLY | O_NOFOLLOW;
duke@435:   }
duke@435:   else if (mode == PerfMemory::PERF_MODE_RW) {
duke@435: #ifdef LATER
duke@435:     mmap_prot = PROT_READ | PROT_WRITE;
gthornbr@7493:     file_flags = O_RDWR | O_NOFOLLOW;
duke@435: #else
duke@435:     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
duke@435:               "Unsupported access mode");
duke@435: #endif
duke@435:   }
duke@435:   else {
duke@435:     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
duke@435:               "Illegal access mode");
duke@435:   }
duke@435: 
duke@435:   if (user == NULL || strlen(user) == 0) {
duke@435:     luser = get_user_name(vmid, CHECK);
duke@435:   }
duke@435:   else {
duke@435:     luser = user;
duke@435:   }
duke@435: 
duke@435:   if (luser == NULL) {
duke@435:     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
duke@435:               "Could not map vmid to user Name");
duke@435:   }
duke@435: 
duke@435:   char* dirname = get_user_tmp_dir(luser);
duke@435: 
duke@435:   // since we don't follow symbolic links when creating the backing
duke@435:   // store file, we don't follow them when attaching either.
duke@435:   //
duke@435:   if (!is_directory_secure(dirname)) {
zgu@3900:     FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
duke@435:     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
duke@435:               "Process not found");
duke@435:   }
duke@435: 
duke@435:   char* filename = get_sharedmem_filename(dirname, vmid);
duke@435: 
duke@435:   // copy heap memory to resource memory. the open_sharedmem_file
duke@435:   // method below need to use the filename, but could throw an
duke@435:   // exception. using a resource array prevents the leak that
duke@435:   // would otherwise occur.
duke@435:   char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
duke@435:   strcpy(rfilename, filename);
duke@435: 
duke@435:   // free the c heap resources that are no longer needed
zgu@3900:   if (luser != user) FREE_C_HEAP_ARRAY(char, luser, mtInternal);
zgu@3900:   FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
zgu@3900:   FREE_C_HEAP_ARRAY(char, filename, mtInternal);
duke@435: 
duke@435:   // open the shared memory file for the give vmid
dcubed@6414:   fd = open_sharedmem_file(rfilename, file_flags, THREAD);
dcubed@6414: 
dcubed@6414:   if (fd == OS_ERR) {
dcubed@6414:     return;
dcubed@6414:   }
dcubed@6414: 
dcubed@6414:   if (HAS_PENDING_EXCEPTION) {
dcubed@6414:     ::close(fd);
dcubed@6414:     return;
dcubed@6414:   }
duke@435: 
duke@435:   if (*sizep == 0) {
duke@435:     size = sharedmem_filesize(fd, CHECK);
ccheung@4893:   } else {
ccheung@4893:     size = *sizep;
duke@435:   }
duke@435: 
ccheung@4893:   assert(size > 0, "unexpected size <= 0");
ccheung@4893: 
duke@435:   mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0);
duke@435: 
rdurbin@5264:   result = ::close(fd);
duke@435:   assert(result != OS_ERR, "could not close file");
duke@435: 
duke@435:   if (mapAddress == MAP_FAILED) {
duke@435:     if (PrintMiscellaneous && Verbose) {
duke@435:       warning("mmap failed: %s\n", strerror(errno));
duke@435:     }
duke@435:     THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
duke@435:               "Could not map PerfMemory");
duke@435:   }
duke@435: 
zgu@4193:   // it does not go through os api, the operation has to record from here
zgu@7074:   MemTracker::record_virtual_memory_reserve_and_commit((address)mapAddress, size, CURRENT_PC, mtInternal);
zgu@4193: 
duke@435:   *addr = mapAddress;
duke@435:   *sizep = size;
duke@435: 
duke@435:   if (PerfTraceMemOps) {
duke@435:     tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at "
drchase@6680:                INTPTR_FORMAT "\n", size, vmid, p2i((void*)mapAddress));
duke@435:   }
duke@435: }
duke@435: 
duke@435: 
duke@435: 
duke@435: 
duke@435: // create the PerfData memory region
duke@435: //
duke@435: // This method creates the memory region used to store performance
duke@435: // data for the JVM. The memory may be created in standard or
duke@435: // shared memory.
duke@435: //
duke@435: void PerfMemory::create_memory_region(size_t size) {
duke@435: 
duke@435:   if (PerfDisableSharedMem) {
duke@435:     // do not share the memory for the performance data.
duke@435:     _start = create_standard_memory(size);
duke@435:   }
duke@435:   else {
duke@435:     _start = create_shared_memory(size);
duke@435:     if (_start == NULL) {
duke@435: 
duke@435:       // creation of the shared memory region failed, attempt
duke@435:       // to create a contiguous, non-shared memory region instead.
duke@435:       //
duke@435:       if (PrintMiscellaneous && Verbose) {
duke@435:         warning("Reverting to non-shared PerfMemory region.\n");
duke@435:       }
duke@435:       PerfDisableSharedMem = true;
duke@435:       _start = create_standard_memory(size);
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   if (_start != NULL) _capacity = size;
duke@435: 
duke@435: }
duke@435: 
duke@435: // delete the PerfData memory region
duke@435: //
duke@435: // This method deletes the memory region used to store performance
duke@435: // data for the JVM. The memory region indicated by the <address, size>
duke@435: // tuple will be inaccessible after a call to this method.
duke@435: //
duke@435: void PerfMemory::delete_memory_region() {
duke@435: 
duke@435:   assert((start() != NULL && capacity() > 0), "verify proper state");
duke@435: 
duke@435:   // If user specifies PerfDataSaveFile, it will save the performance data
duke@435:   // to the specified file name no matter whether PerfDataSaveToFile is specified
duke@435:   // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
duke@435:   // -XX:+PerfDataSaveToFile.
duke@435:   if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
duke@435:     save_memory_to_file(start(), capacity());
duke@435:   }
duke@435: 
duke@435:   if (PerfDisableSharedMem) {
duke@435:     delete_standard_memory(start(), capacity());
duke@435:   }
duke@435:   else {
duke@435:     delete_shared_memory(start(), capacity());
duke@435:   }
duke@435: }
duke@435: 
duke@435: // attach to the PerfData memory region for another JVM
duke@435: //
duke@435: // This method returns an <address, size> tuple that points to
duke@435: // a memory buffer that is kept reasonably synchronized with
duke@435: // the PerfData memory region for the indicated JVM. This
duke@435: // buffer may be kept in synchronization via shared memory
duke@435: // or some other mechanism that keeps the buffer updated.
duke@435: //
duke@435: // If the JVM chooses not to support the attachability feature,
duke@435: // this method should throw an UnsupportedOperation exception.
duke@435: //
duke@435: // This implementation utilizes named shared memory to map
duke@435: // the indicated process's PerfData memory region into this JVMs
duke@435: // address space.
duke@435: //
duke@435: void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, char** addrp, size_t* sizep, TRAPS) {
duke@435: 
duke@435:   if (vmid == 0 || vmid == os::current_process_id()) {
duke@435:      *addrp = start();
duke@435:      *sizep = capacity();
duke@435:      return;
duke@435:   }
duke@435: 
duke@435:   mmap_attach_shared(user, vmid, mode, addrp, sizep, CHECK);
duke@435: }
duke@435: 
duke@435: // detach from the PerfData memory region of another JVM
duke@435: //
duke@435: // This method detaches the PerfData memory region of another
duke@435: // JVM, specified as an <address, size> tuple of a buffer
duke@435: // in this process's address space. This method may perform
duke@435: // arbitrary actions to accomplish the detachment. The memory
duke@435: // region specified by <address, size> will be inaccessible after
duke@435: // a call to this method.
duke@435: //
duke@435: // If the JVM chooses not to support the attachability feature,
duke@435: // this method should throw an UnsupportedOperation exception.
duke@435: //
duke@435: // This implementation utilizes named shared memory to detach
duke@435: // the indicated process's PerfData memory region from this
duke@435: // process's address space.
duke@435: //
duke@435: void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
duke@435: 
duke@435:   assert(addr != 0, "address sanity check");
duke@435:   assert(bytes > 0, "capacity sanity check");
duke@435: 
duke@435:   if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
duke@435:     // prevent accidental detachment of this process's PerfMemory region
duke@435:     return;
duke@435:   }
duke@435: 
duke@435:   unmap_shared(addr, bytes);
duke@435: }
duke@435: 
duke@435: char* PerfMemory::backing_store_filename() {
duke@435:   return backing_store_file_name;
duke@435: }