aoqi@0: /*
phh@9507:  * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * Copyright 2012, 2013 SAP AG. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #include "precompiled.hpp"
aoqi@0: #include "classfile/vmSymbols.hpp"
aoqi@0: #include "memory/allocation.inline.hpp"
aoqi@0: #include "memory/resourceArea.hpp"
aoqi@0: #include "oops/oop.inline.hpp"
aoqi@0: #include "os_aix.inline.hpp"
aoqi@0: #include "runtime/handles.inline.hpp"
aoqi@0: #include "runtime/perfMemory.hpp"
goetz@7515: #include "services/memTracker.hpp"
aoqi@0: #include "utilities/exceptions.hpp"
aoqi@0: 
aoqi@0: // put OS-includes here
aoqi@0: # include <sys/types.h>
aoqi@0: # include <sys/mman.h>
aoqi@0: # include <errno.h>
aoqi@0: # include <stdio.h>
aoqi@0: # include <unistd.h>
aoqi@0: # include <sys/stat.h>
aoqi@0: # include <signal.h>
aoqi@0: # include <pwd.h>
aoqi@0: 
aoqi@0: static char* backing_store_file_name = NULL;  // name of the backing store
aoqi@0:                                               // file, if successfully created.
aoqi@0: 
aoqi@0: // Standard Memory Implementation Details
aoqi@0: 
aoqi@0: // create the PerfData memory region in standard memory.
aoqi@0: //
aoqi@0: static char* create_standard_memory(size_t size) {
aoqi@0: 
aoqi@0:   // allocate an aligned chuck of memory
aoqi@0:   char* mapAddress = os::reserve_memory(size);
aoqi@0: 
aoqi@0:   if (mapAddress == NULL) {
aoqi@0:     return NULL;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // commit memory
aoqi@0:   if (!os::commit_memory(mapAddress, size, !ExecMem)) {
aoqi@0:     if (PrintMiscellaneous && Verbose) {
aoqi@0:       warning("Could not commit PerfData memory\n");
aoqi@0:     }
aoqi@0:     os::release_memory(mapAddress, size);
aoqi@0:     return NULL;
aoqi@0:   }
aoqi@0: 
aoqi@0:   return mapAddress;
aoqi@0: }
aoqi@0: 
aoqi@0: // delete the PerfData memory region
aoqi@0: //
aoqi@0: static void delete_standard_memory(char* addr, size_t size) {
aoqi@0: 
aoqi@0:   // there are no persistent external resources to cleanup for standard
aoqi@0:   // memory. since DestroyJavaVM does not support unloading of the JVM,
aoqi@0:   // cleanup of the memory resource is not performed. The memory will be
aoqi@0:   // reclaimed by the OS upon termination of the process.
aoqi@0:   //
aoqi@0:   return;
aoqi@0: }
aoqi@0: 
aoqi@0: // save the specified memory region to the given file
aoqi@0: //
aoqi@0: // Note: this function might be called from signal handler (by os::abort()),
aoqi@0: // don't allocate heap memory.
aoqi@0: //
aoqi@0: static void save_memory_to_file(char* addr, size_t size) {
aoqi@0: 
aoqi@0:   const char* destfile = PerfMemory::get_perfdata_file_path();
aoqi@0:   assert(destfile[0] != '\0', "invalid PerfData file path");
aoqi@0: 
aoqi@0:   int result;
aoqi@0: 
aoqi@0:   RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE),
aoqi@0:               result);;
aoqi@0:   if (result == OS_ERR) {
aoqi@0:     if (PrintMiscellaneous && Verbose) {
aoqi@0:       warning("Could not create Perfdata save file: %s: %s\n",
aoqi@0:               destfile, strerror(errno));
aoqi@0:     }
aoqi@0:   } else {
aoqi@0:     int fd = result;
aoqi@0: 
aoqi@0:     for (size_t remaining = size; remaining > 0;) {
aoqi@0: 
aoqi@0:       RESTARTABLE(::write(fd, addr, remaining), result);
aoqi@0:       if (result == OS_ERR) {
aoqi@0:         if (PrintMiscellaneous && Verbose) {
aoqi@0:           warning("Could not write Perfdata save file: %s: %s\n",
aoqi@0:                   destfile, strerror(errno));
aoqi@0:         }
aoqi@0:         break;
aoqi@0:       }
aoqi@0: 
aoqi@0:       remaining -= (size_t)result;
aoqi@0:       addr += result;
aoqi@0:     }
aoqi@0: 
aoqi@0:     RESTARTABLE(::close(fd), result);
aoqi@0:     if (PrintMiscellaneous && Verbose) {
aoqi@0:       if (result == OS_ERR) {
aoqi@0:         warning("Could not close %s: %s\n", destfile, strerror(errno));
aoqi@0:       }
aoqi@0:     }
aoqi@0:   }
aoqi@0:   FREE_C_HEAP_ARRAY(char, destfile, mtInternal);
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: // Shared Memory Implementation Details
aoqi@0: 
aoqi@0: // Note: the solaris and linux shared memory implementation uses the mmap
aoqi@0: // interface with a backing store file to implement named shared memory.
aoqi@0: // Using the file system as the name space for shared memory allows a
aoqi@0: // common name space to be supported across a variety of platforms. It
aoqi@0: // also provides a name space that Java applications can deal with through
aoqi@0: // simple file apis.
aoqi@0: //
aoqi@0: // The solaris and linux implementations store the backing store file in
aoqi@0: // a user specific temporary directory located in the /tmp file system,
aoqi@0: // which is always a local file system and is sometimes a RAM based file
aoqi@0: // system.
aoqi@0: 
aoqi@0: // return the user specific temporary directory name.
aoqi@0: //
aoqi@0: // the caller is expected to free the allocated memory.
aoqi@0: //
aoqi@0: static char* get_user_tmp_dir(const char* user) {
aoqi@0: 
aoqi@0:   const char* tmpdir = os::get_temp_directory();
aoqi@0:   const char* perfdir = PERFDATA_NAME;
aoqi@0:   size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3;
aoqi@0:   char* dirname = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
aoqi@0: 
aoqi@0:   // construct the path name to user specific tmp directory
aoqi@0:   snprintf(dirname, nbytes, "%s/%s_%s", tmpdir, perfdir, user);
aoqi@0: 
aoqi@0:   return dirname;
aoqi@0: }
aoqi@0: 
aoqi@0: // convert the given file name into a process id. if the file
aoqi@0: // does not meet the file naming constraints, return 0.
aoqi@0: //
aoqi@0: static pid_t filename_to_pid(const char* filename) {
aoqi@0: 
aoqi@0:   // a filename that doesn't begin with a digit is not a
aoqi@0:   // candidate for conversion.
aoqi@0:   //
aoqi@0:   if (!isdigit(*filename)) {
aoqi@0:     return 0;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // check if file name can be converted to an integer without
aoqi@0:   // any leftover characters.
aoqi@0:   //
aoqi@0:   char* remainder = NULL;
aoqi@0:   errno = 0;
aoqi@0:   pid_t pid = (pid_t)strtol(filename, &remainder, 10);
aoqi@0: 
aoqi@0:   if (errno != 0) {
aoqi@0:     return 0;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // check for left over characters. If any, then the filename is
aoqi@0:   // not a candidate for conversion.
aoqi@0:   //
aoqi@0:   if (remainder != NULL && *remainder != '\0') {
aoqi@0:     return 0;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // successful conversion, return the pid
aoqi@0:   return pid;
aoqi@0: }
aoqi@0: 
goetz@7515: // Check if the given statbuf is considered a secure directory for
goetz@7515: // the backing store files. Returns true if the directory is considered
goetz@7515: // a secure location. Returns false if the statbuf is a symbolic link or
goetz@7515: // if an error occurred.
clanger@8210: //
goetz@7515: static bool is_statbuf_secure(struct stat *statp) {
goetz@7515:   if (S_ISLNK(statp->st_mode) || !S_ISDIR(statp->st_mode)) {
goetz@7515:     // The path represents a link or some non-directory file type,
goetz@7515:     // which is not what we expected. Declare it insecure.
goetz@7515:     //
goetz@7515:     return false;
goetz@7515:   }
goetz@7515:   // We have an existing directory, check if the permissions are safe.
clanger@8210:   //
goetz@7515:   if ((statp->st_mode & (S_IWGRP|S_IWOTH)) != 0) {
goetz@7515:     // The directory is open for writing and could be subjected
goetz@7515:     // to a symlink or a hard link attack. Declare it insecure.
clanger@8210:     //
goetz@7515:     return false;
goetz@7515:   }
clanger@8210:   // If user is not root then see if the uid of the directory matches the effective uid of the process.
clanger@8210:   uid_t euid = geteuid();
clanger@8210:   if ((euid != 0) && (statp->st_uid != euid)) {
goetz@7515:     // The directory was not created by this user, declare it insecure.
clanger@8210:     //
goetz@7515:     return false;
goetz@7515:   }
goetz@7515:   return true;
goetz@7515: }
aoqi@0: 
goetz@7515: 
goetz@7515: // Check if the given path is considered a secure directory for
aoqi@0: // the backing store files. Returns true if the directory exists
aoqi@0: // and is considered a secure location. Returns false if the path
aoqi@0: // is a symbolic link or if an error occurred.
clanger@8210: //
aoqi@0: static bool is_directory_secure(const char* path) {
aoqi@0:   struct stat statbuf;
aoqi@0:   int result = 0;
aoqi@0: 
aoqi@0:   RESTARTABLE(::lstat(path, &statbuf), result);
aoqi@0:   if (result == OS_ERR) {
aoqi@0:     return false;
aoqi@0:   }
aoqi@0: 
goetz@7515:   // The path exists, see if it is secure.
goetz@7515:   return is_statbuf_secure(&statbuf);
goetz@7515: }
goetz@7515: 
goetz@7515: // (Taken over from Solaris to support the O_NOFOLLOW case on AIX.)
goetz@7515: // Check if the given directory file descriptor is considered a secure
goetz@7515: // directory for the backing store files. Returns true if the directory
goetz@7515: // exists and is considered a secure location. Returns false if the path
goetz@7515: // is a symbolic link or if an error occurred.
goetz@7515: static bool is_dirfd_secure(int dir_fd) {
goetz@7515:   struct stat statbuf;
goetz@7515:   int result = 0;
goetz@7515: 
goetz@7515:   RESTARTABLE(::fstat(dir_fd, &statbuf), result);
goetz@7515:   if (result == OS_ERR) {
aoqi@0:     return false;
aoqi@0:   }
goetz@7515: 
goetz@7515:   // The path exists, now check its mode.
goetz@7515:   return is_statbuf_secure(&statbuf);
goetz@7515: }
goetz@7515: 
goetz@7515: 
goetz@7515: // Check to make sure fd1 and fd2 are referencing the same file system object.
goetz@7515: static bool is_same_fsobject(int fd1, int fd2) {
goetz@7515:   struct stat statbuf1;
goetz@7515:   struct stat statbuf2;
goetz@7515:   int result = 0;
goetz@7515: 
goetz@7515:   RESTARTABLE(::fstat(fd1, &statbuf1), result);
goetz@7515:   if (result == OS_ERR) {
goetz@7515:     return false;
goetz@7515:   }
goetz@7515:   RESTARTABLE(::fstat(fd2, &statbuf2), result);
goetz@7515:   if (result == OS_ERR) {
goetz@7515:     return false;
goetz@7515:   }
goetz@7515: 
goetz@7515:   if ((statbuf1.st_ino == statbuf2.st_ino) &&
goetz@7515:       (statbuf1.st_dev == statbuf2.st_dev)) {
goetz@7515:     return true;
goetz@7515:   } else {
goetz@7515:     return false;
goetz@7515:   }
goetz@7515: }
goetz@7515: 
goetz@7515: // Helper functions for open without O_NOFOLLOW which is not present on AIX 5.3/6.1.
goetz@7515: // We use the jdk6 implementation here.
goetz@7515: #ifndef O_NOFOLLOW
goetz@7515: // The O_NOFOLLOW oflag doesn't exist before solaris 5.10, this is to simulate that behaviour
goetz@7515: // was done in jdk 5/6 hotspot by Oracle this way
goetz@7515: static int open_o_nofollow_impl(const char* path, int oflag, mode_t mode, bool use_mode) {
goetz@7515:   struct stat orig_st;
goetz@7515:   struct stat new_st;
goetz@7515:   bool create;
goetz@7515:   int error;
goetz@7515:   int fd;
goetz@7515: 
goetz@7515:   create = false;
goetz@7515: 
goetz@7515:   if (lstat(path, &orig_st) != 0) {
goetz@7515:     if (errno == ENOENT && (oflag & O_CREAT) != 0) {
goetz@7515:       // File doesn't exist, but_we want to create it, add O_EXCL flag
goetz@7515:       // to make sure no-one creates it (or a symlink) before us
goetz@7515:       // This works as we expect with symlinks, from posix man page:
goetz@7515:       // 'If O_EXCL  and  O_CREAT  are set, and path names a symbolic
goetz@7515:       // link, open() shall fail and set errno to [EEXIST]'.
goetz@7515:       oflag |= O_EXCL;
goetz@7515:       create = true;
goetz@7515:     } else {
goetz@7515:       // File doesn't exist, and we are not creating it.
goetz@7515:       return OS_ERR;
aoqi@0:     }
goetz@7515:   } else {
goetz@7515:     // Lstat success, check if existing file is a link.
goetz@7515:     if ((orig_st.st_mode & S_IFMT) == S_IFLNK)  {
goetz@7515:       // File is a symlink.
goetz@7515:       errno = ELOOP;
goetz@7515:       return OS_ERR;
goetz@7515:     }
goetz@7515:   }
goetz@7515: 
goetz@7515:   if (use_mode == true) {
goetz@7515:     fd = open(path, oflag, mode);
goetz@7515:   } else {
goetz@7515:     fd = open(path, oflag);
goetz@7515:   }
goetz@7515: 
goetz@7515:   if (fd == OS_ERR) {
goetz@7515:     return fd;
goetz@7515:   }
goetz@7515: 
goetz@7515:   // Can't do inode checks on before/after if we created the file.
goetz@7515:   if (create == false) {
goetz@7515:     if (fstat(fd, &new_st) != 0) {
goetz@7515:       // Keep errno from fstat, in case close also fails.
goetz@7515:       error = errno;
goetz@7515:       ::close(fd);
goetz@7515:       errno = error;
goetz@7515:       return OS_ERR;
goetz@7515:     }
goetz@7515: 
goetz@7515:     if (orig_st.st_dev != new_st.st_dev || orig_st.st_ino != new_st.st_ino) {
goetz@7515:       // File was tampered with during race window.
goetz@7515:       ::close(fd);
goetz@7515:       errno = EEXIST;
goetz@7515:       if (PrintMiscellaneous && Verbose) {
goetz@7515:         warning("possible file tampering attempt detected when opening %s", path);
goetz@7515:       }
goetz@7515:       return OS_ERR;
goetz@7515:     }
goetz@7515:   }
goetz@7515: 
goetz@7515:   return fd;
goetz@7515: }
goetz@7515: 
goetz@7515: static int open_o_nofollow(const char* path, int oflag, mode_t mode) {
goetz@7515:   return open_o_nofollow_impl(path, oflag, mode, true);
goetz@7515: }
goetz@7515: 
goetz@7515: static int open_o_nofollow(const char* path, int oflag) {
goetz@7515:   return open_o_nofollow_impl(path, oflag, 0, false);
goetz@7515: }
goetz@7515: #endif
goetz@7515: 
goetz@7515: // Open the directory of the given path and validate it.
goetz@7515: // Return a DIR * of the open directory.
goetz@7515: static DIR *open_directory_secure(const char* dirname) {
goetz@7515:   // Open the directory using open() so that it can be verified
goetz@7515:   // to be secure by calling is_dirfd_secure(), opendir() and then check
goetz@7515:   // to see if they are the same file system object.  This method does not
goetz@7515:   // introduce a window of opportunity for the directory to be attacked that
goetz@7515:   // calling opendir() and is_directory_secure() does.
goetz@7515:   int result;
goetz@7515:   DIR *dirp = NULL;
goetz@7515: 
goetz@7515:   // No O_NOFOLLOW defined at buildtime, and it is not documented for open;
goetz@7515:   // so provide a workaround in this case.
goetz@7515: #ifdef O_NOFOLLOW
goetz@7515:   RESTARTABLE(::open(dirname, O_RDONLY|O_NOFOLLOW), result);
goetz@7515: #else
goetz@7515:   // workaround (jdk6 coding)
goetz@7515:   RESTARTABLE(::open_o_nofollow(dirname, O_RDONLY), result);
goetz@7515: #endif
goetz@7515: 
goetz@7515:   if (result == OS_ERR) {
goetz@7515:     // Directory doesn't exist or is a symlink, so there is nothing to cleanup.
goetz@7515:     if (PrintMiscellaneous && Verbose) {
goetz@7515:       if (errno == ELOOP) {
goetz@7515:         warning("directory %s is a symlink and is not secure\n", dirname);
goetz@7515:       } else {
goetz@7515:         warning("could not open directory %s: %s\n", dirname, strerror(errno));
goetz@7515:       }
goetz@7515:     }
goetz@7515:     return dirp;
goetz@7515:   }
goetz@7515:   int fd = result;
goetz@7515: 
goetz@7515:   // Determine if the open directory is secure.
goetz@7515:   if (!is_dirfd_secure(fd)) {
goetz@7515:     // The directory is not a secure directory.
goetz@7515:     os::close(fd);
goetz@7515:     return dirp;
goetz@7515:   }
goetz@7515: 
goetz@7515:   // Open the directory.
goetz@7515:   dirp = ::opendir(dirname);
goetz@7515:   if (dirp == NULL) {
goetz@7515:     // The directory doesn't exist, close fd and return.
goetz@7515:     os::close(fd);
goetz@7515:     return dirp;
goetz@7515:   }
goetz@7515: 
goetz@7515:   // Check to make sure fd and dirp are referencing the same file system object.
goetz@7515:   if (!is_same_fsobject(fd, dirp->dd_fd)) {
goetz@7515:     // The directory is not secure.
goetz@7515:     os::close(fd);
goetz@7515:     os::closedir(dirp);
goetz@7515:     dirp = NULL;
goetz@7515:     return dirp;
goetz@7515:   }
goetz@7515: 
goetz@7515:   // Close initial open now that we know directory is secure
goetz@7515:   os::close(fd);
goetz@7515: 
goetz@7515:   return dirp;
goetz@7515: }
goetz@7515: 
goetz@7515: // NOTE: The code below uses fchdir(), open() and unlink() because
goetz@7515: // fdopendir(), openat() and unlinkat() are not supported on all
goetz@7515: // versions.  Once the support for fdopendir(), openat() and unlinkat()
goetz@7515: // is available on all supported versions the code can be changed
goetz@7515: // to use these functions.
goetz@7515: 
goetz@7515: // Open the directory of the given path, validate it and set the
goetz@7515: // current working directory to it.
goetz@7515: // Return a DIR * of the open directory and the saved cwd fd.
goetz@7515: //
goetz@7515: static DIR *open_directory_secure_cwd(const char* dirname, int *saved_cwd_fd) {
goetz@7515: 
goetz@7515:   // Open the directory.
goetz@7515:   DIR* dirp = open_directory_secure(dirname);
goetz@7515:   if (dirp == NULL) {
goetz@7515:     // Directory doesn't exist or is insecure, so there is nothing to cleanup.
goetz@7515:     return dirp;
goetz@7515:   }
goetz@7515:   int fd = dirp->dd_fd;
goetz@7515: 
goetz@7515:   // Open a fd to the cwd and save it off.
goetz@7515:   int result;
goetz@7515:   RESTARTABLE(::open(".", O_RDONLY), result);
goetz@7515:   if (result == OS_ERR) {
goetz@7515:     *saved_cwd_fd = -1;
goetz@7515:   } else {
goetz@7515:     *saved_cwd_fd = result;
goetz@7515:   }
goetz@7515: 
clanger@8177:   // Set the current directory to dirname by using the fd of the directory and
clanger@8177:   // handle errors, otherwise shared memory files will be created in cwd.
goetz@7515:   result = fchdir(fd);
clanger@8177:   if (result == OS_ERR) {
clanger@8177:     if (PrintMiscellaneous && Verbose) {
clanger@8177:       warning("could not change to directory %s", dirname);
clanger@8177:     }
clanger@8177:     if (*saved_cwd_fd != -1) {
clanger@8177:       ::close(*saved_cwd_fd);
clanger@8177:       *saved_cwd_fd = -1;
clanger@8177:     }
clanger@8177:     // Close the directory.
clanger@8177:     os::closedir(dirp);
clanger@8177:     return NULL;
clanger@8177:   } else {
clanger@8177:     return dirp;
clanger@8177:   }
goetz@7515: }
goetz@7515: 
goetz@7515: // Close the directory and restore the current working directory.
clanger@8177: //
goetz@7515: static void close_directory_secure_cwd(DIR* dirp, int saved_cwd_fd) {
goetz@7515: 
goetz@7515:   int result;
goetz@7515:   // If we have a saved cwd change back to it and close the fd.
goetz@7515:   if (saved_cwd_fd != -1) {
goetz@7515:     result = fchdir(saved_cwd_fd);
goetz@7515:     ::close(saved_cwd_fd);
goetz@7515:   }
goetz@7515: 
goetz@7515:   // Close the directory.
goetz@7515:   os::closedir(dirp);
goetz@7515: }
goetz@7515: 
goetz@7515: // Check if the given file descriptor is considered a secure.
goetz@7515: static bool is_file_secure(int fd, const char *filename) {
goetz@7515: 
goetz@7515:   int result;
goetz@7515:   struct stat statbuf;
goetz@7515: 
goetz@7515:   // Determine if the file is secure.
goetz@7515:   RESTARTABLE(::fstat(fd, &statbuf), result);
goetz@7515:   if (result == OS_ERR) {
goetz@7515:     if (PrintMiscellaneous && Verbose) {
goetz@7515:       warning("fstat failed on %s: %s\n", filename, strerror(errno));
goetz@7515:     }
goetz@7515:     return false;
goetz@7515:   }
goetz@7515:   if (statbuf.st_nlink > 1) {
goetz@7515:     // A file with multiple links is not expected.
goetz@7515:     if (PrintMiscellaneous && Verbose) {
goetz@7515:       warning("file %s has multiple links\n", filename);
goetz@7515:     }
goetz@7515:     return false;
aoqi@0:   }
aoqi@0:   return true;
aoqi@0: }
aoqi@0: 
goetz@7515: // Return the user name for the given user id.
aoqi@0: //
goetz@7515: // The caller is expected to free the allocated memory.
aoqi@0: static char* get_user_name(uid_t uid) {
aoqi@0: 
aoqi@0:   struct passwd pwent;
aoqi@0: 
goetz@7515:   // Determine the max pwbuf size from sysconf, and hardcode
aoqi@0:   // a default if this not available through sysconf.
aoqi@0:   long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
aoqi@0:   if (bufsize == -1)
aoqi@0:     bufsize = 1024;
aoqi@0: 
aoqi@0:   char* pwbuf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
aoqi@0: 
aoqi@0:   // POSIX interface to getpwuid_r is used on LINUX
aoqi@0:   struct passwd* p;
aoqi@0:   int result = getpwuid_r(uid, &pwent, pwbuf, (size_t)bufsize, &p);
aoqi@0: 
aoqi@0:   if (result != 0 || p == NULL || p->pw_name == NULL || *(p->pw_name) == '\0') {
aoqi@0:     if (PrintMiscellaneous && Verbose) {
aoqi@0:       if (result != 0) {
aoqi@0:         warning("Could not retrieve passwd entry: %s\n",
aoqi@0:                 strerror(result));
aoqi@0:       }
aoqi@0:       else if (p == NULL) {
aoqi@0:         // this check is added to protect against an observed problem
aoqi@0:         // with getpwuid_r() on RedHat 9 where getpwuid_r returns 0,
aoqi@0:         // indicating success, but has p == NULL. This was observed when
aoqi@0:         // inserting a file descriptor exhaustion fault prior to the call
aoqi@0:         // getpwuid_r() call. In this case, error is set to the appropriate
aoqi@0:         // error condition, but this is undocumented behavior. This check
aoqi@0:         // is safe under any condition, but the use of errno in the output
aoqi@0:         // message may result in an erroneous message.
aoqi@0:         // Bug Id 89052 was opened with RedHat.
aoqi@0:         //
aoqi@0:         warning("Could not retrieve passwd entry: %s\n",
aoqi@0:                 strerror(errno));
aoqi@0:       }
aoqi@0:       else {
aoqi@0:         warning("Could not determine user name: %s\n",
aoqi@0:                 p->pw_name == NULL ? "pw_name = NULL" :
aoqi@0:                                      "pw_name zero length");
aoqi@0:       }
aoqi@0:     }
aoqi@0:     FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal);
aoqi@0:     return NULL;
aoqi@0:   }
aoqi@0: 
aoqi@0:   char* user_name = NEW_C_HEAP_ARRAY(char, strlen(p->pw_name) + 1, mtInternal);
aoqi@0:   strcpy(user_name, p->pw_name);
aoqi@0: 
aoqi@0:   FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal);
aoqi@0:   return user_name;
aoqi@0: }
aoqi@0: 
aoqi@0: // return the name of the user that owns the process identified by vmid.
aoqi@0: //
aoqi@0: // This method uses a slow directory search algorithm to find the backing
aoqi@0: // store file for the specified vmid and returns the user name, as determined
aoqi@0: // by the user name suffix of the hsperfdata_<username> directory name.
aoqi@0: //
aoqi@0: // the caller is expected to free the allocated memory.
aoqi@0: //
aoqi@0: static char* get_user_name_slow(int vmid, TRAPS) {
aoqi@0: 
aoqi@0:   // short circuit the directory search if the process doesn't even exist.
aoqi@0:   if (kill(vmid, 0) == OS_ERR) {
aoqi@0:     if (errno == ESRCH) {
aoqi@0:       THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
aoqi@0:                   "Process not found");
aoqi@0:     }
aoqi@0:     else /* EPERM */ {
aoqi@0:       THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
aoqi@0:     }
aoqi@0:   }
aoqi@0: 
aoqi@0:   // directory search
aoqi@0:   char* oldest_user = NULL;
aoqi@0:   time_t oldest_ctime = 0;
aoqi@0: 
aoqi@0:   const char* tmpdirname = os::get_temp_directory();
aoqi@0: 
aoqi@0:   DIR* tmpdirp = os::opendir(tmpdirname);
aoqi@0: 
aoqi@0:   if (tmpdirp == NULL) {
aoqi@0:     return NULL;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // for each entry in the directory that matches the pattern hsperfdata_*,
aoqi@0:   // open the directory and check if the file for the given vmid exists.
aoqi@0:   // The file with the expected name and the latest creation date is used
aoqi@0:   // to determine the user name for the process id.
aoqi@0:   //
aoqi@0:   struct dirent* dentry;
aoqi@0:   errno = 0;
andrew@9711:   while ((dentry = os::readdir(tmpdirp)) != NULL) {
aoqi@0: 
aoqi@0:     // check if the directory entry is a hsperfdata file
aoqi@0:     if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
aoqi@0:       continue;
aoqi@0:     }
aoqi@0: 
aoqi@0:     char* usrdir_name = NEW_C_HEAP_ARRAY(char,
aoqi@0:                               strlen(tmpdirname) + strlen(dentry->d_name) + 2, mtInternal);
aoqi@0:     strcpy(usrdir_name, tmpdirname);
aoqi@0:     strcat(usrdir_name, "/");
aoqi@0:     strcat(usrdir_name, dentry->d_name);
aoqi@0: 
goetz@7515:     // Open the user directory.
goetz@7515:     DIR* subdirp = open_directory_secure(usrdir_name);
aoqi@0: 
aoqi@0:     if (subdirp == NULL) {
aoqi@0:       FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
aoqi@0:       continue;
aoqi@0:     }
aoqi@0: 
aoqi@0:     // Since we don't create the backing store files in directories
aoqi@0:     // pointed to by symbolic links, we also don't follow them when
aoqi@0:     // looking for the files. We check for a symbolic link after the
aoqi@0:     // call to opendir in order to eliminate a small window where the
aoqi@0:     // symlink can be exploited.
aoqi@0:     //
aoqi@0:     if (!is_directory_secure(usrdir_name)) {
aoqi@0:       FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
aoqi@0:       os::closedir(subdirp);
aoqi@0:       continue;
aoqi@0:     }
aoqi@0: 
aoqi@0:     struct dirent* udentry;
aoqi@0:     errno = 0;
andrew@9711:     while ((udentry = os::readdir(subdirp)) != NULL) {
aoqi@0: 
aoqi@0:       if (filename_to_pid(udentry->d_name) == vmid) {
aoqi@0:         struct stat statbuf;
aoqi@0:         int result;
aoqi@0: 
aoqi@0:         char* filename = NEW_C_HEAP_ARRAY(char,
aoqi@0:                             strlen(usrdir_name) + strlen(udentry->d_name) + 2, mtInternal);
aoqi@0: 
aoqi@0:         strcpy(filename, usrdir_name);
aoqi@0:         strcat(filename, "/");
aoqi@0:         strcat(filename, udentry->d_name);
aoqi@0: 
aoqi@0:         // don't follow symbolic links for the file
aoqi@0:         RESTARTABLE(::lstat(filename, &statbuf), result);
aoqi@0:         if (result == OS_ERR) {
aoqi@0:            FREE_C_HEAP_ARRAY(char, filename, mtInternal);
aoqi@0:            continue;
aoqi@0:         }
aoqi@0: 
aoqi@0:         // skip over files that are not regular files.
aoqi@0:         if (!S_ISREG(statbuf.st_mode)) {
aoqi@0:           FREE_C_HEAP_ARRAY(char, filename, mtInternal);
aoqi@0:           continue;
aoqi@0:         }
aoqi@0: 
aoqi@0:         // compare and save filename with latest creation time
aoqi@0:         if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) {
aoqi@0: 
aoqi@0:           if (statbuf.st_ctime > oldest_ctime) {
aoqi@0:             char* user = strchr(dentry->d_name, '_') + 1;
aoqi@0: 
aoqi@0:             if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user, mtInternal);
aoqi@0:             oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
aoqi@0: 
aoqi@0:             strcpy(oldest_user, user);
aoqi@0:             oldest_ctime = statbuf.st_ctime;
aoqi@0:           }
aoqi@0:         }
aoqi@0: 
aoqi@0:         FREE_C_HEAP_ARRAY(char, filename, mtInternal);
aoqi@0:       }
aoqi@0:     }
aoqi@0:     os::closedir(subdirp);
aoqi@0:     FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
aoqi@0:   }
aoqi@0:   os::closedir(tmpdirp);
aoqi@0: 
aoqi@0:   return(oldest_user);
aoqi@0: }
aoqi@0: 
aoqi@0: // return the name of the user that owns the JVM indicated by the given vmid.
aoqi@0: //
aoqi@0: static char* get_user_name(int vmid, TRAPS) {
phh@9507:   return get_user_name_slow(vmid, THREAD);
aoqi@0: }
aoqi@0: 
aoqi@0: // return the file name of the backing store file for the named
aoqi@0: // shared memory region for the given user name and vmid.
aoqi@0: //
aoqi@0: // the caller is expected to free the allocated memory.
aoqi@0: //
aoqi@0: static char* get_sharedmem_filename(const char* dirname, int vmid) {
aoqi@0: 
aoqi@0:   // add 2 for the file separator and a null terminator.
aoqi@0:   size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
aoqi@0: 
aoqi@0:   char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
aoqi@0:   snprintf(name, nbytes, "%s/%d", dirname, vmid);
aoqi@0: 
aoqi@0:   return name;
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: // remove file
aoqi@0: //
aoqi@0: // this method removes the file specified by the given path
aoqi@0: //
aoqi@0: static void remove_file(const char* path) {
aoqi@0: 
aoqi@0:   int result;
aoqi@0: 
aoqi@0:   // if the file is a directory, the following unlink will fail. since
aoqi@0:   // we don't expect to find directories in the user temp directory, we
aoqi@0:   // won't try to handle this situation. even if accidentially or
aoqi@0:   // maliciously planted, the directory's presence won't hurt anything.
aoqi@0:   //
aoqi@0:   RESTARTABLE(::unlink(path), result);
aoqi@0:   if (PrintMiscellaneous && Verbose && result == OS_ERR) {
aoqi@0:     if (errno != ENOENT) {
aoqi@0:       warning("Could not unlink shared memory backing"
aoqi@0:               " store file %s : %s\n", path, strerror(errno));
aoqi@0:     }
aoqi@0:   }
aoqi@0: }
aoqi@0: 
goetz@7515: // Cleanup stale shared memory resources
aoqi@0: //
aoqi@0: // This method attempts to remove all stale shared memory files in
aoqi@0: // the named user temporary directory. It scans the named directory
aoqi@0: // for files matching the pattern ^$[0-9]*$. For each file found, the
aoqi@0: // process id is extracted from the file name and a test is run to
aoqi@0: // determine if the process is alive. If the process is not alive,
aoqi@0: // any stale file resources are removed.
aoqi@0: static void cleanup_sharedmem_resources(const char* dirname) {
aoqi@0: 
goetz@7515:   int saved_cwd_fd;
goetz@7515:   // Open the directory.
goetz@7515:   DIR* dirp = open_directory_secure_cwd(dirname, &saved_cwd_fd);
aoqi@0:   if (dirp == NULL) {
goetz@7515:      // Directory doesn't exist or is insecure, so there is nothing to cleanup.
aoqi@0:     return;
aoqi@0:   }
aoqi@0: 
goetz@7515:   // For each entry in the directory that matches the expected file
aoqi@0:   // name pattern, determine if the file resources are stale and if
aoqi@0:   // so, remove the file resources. Note, instrumented HotSpot processes
aoqi@0:   // for this user may start and/or terminate during this search and
aoqi@0:   // remove or create new files in this directory. The behavior of this
aoqi@0:   // loop under these conditions is dependent upon the implementation of
aoqi@0:   // opendir/readdir.
aoqi@0:   struct dirent* entry;
aoqi@0:   errno = 0;
andrew@9711:   while ((entry = os::readdir(dirp)) != NULL) {
aoqi@0: 
aoqi@0:     pid_t pid = filename_to_pid(entry->d_name);
aoqi@0: 
aoqi@0:     if (pid == 0) {
aoqi@0: 
aoqi@0:       if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
aoqi@0: 
goetz@7515:         // Attempt to remove all unexpected files, except "." and "..".
goetz@7515:         unlink(entry->d_name);
aoqi@0:       }
aoqi@0: 
aoqi@0:       errno = 0;
aoqi@0:       continue;
aoqi@0:     }
aoqi@0: 
goetz@7515:     // We now have a file name that converts to a valid integer
aoqi@0:     // that could represent a process id . if this process id
aoqi@0:     // matches the current process id or the process is not running,
aoqi@0:     // then remove the stale file resources.
aoqi@0:     //
goetz@7515:     // Process liveness is detected by sending signal number 0 to
aoqi@0:     // the process id (see kill(2)). if kill determines that the
aoqi@0:     // process does not exist, then the file resources are removed.
aoqi@0:     // if kill determines that that we don't have permission to
aoqi@0:     // signal the process, then the file resources are assumed to
aoqi@0:     // be stale and are removed because the resources for such a
aoqi@0:     // process should be in a different user specific directory.
aoqi@0:     if ((pid == os::current_process_id()) ||
aoqi@0:         (kill(pid, 0) == OS_ERR && (errno == ESRCH || errno == EPERM))) {
aoqi@0: 
goetz@7515:         unlink(entry->d_name);
aoqi@0:     }
aoqi@0:     errno = 0;
aoqi@0:   }
goetz@7515: 
goetz@7515:   // Close the directory and reset the current working directory.
goetz@7515:   close_directory_secure_cwd(dirp, saved_cwd_fd);
goetz@7515: 
aoqi@0: }
aoqi@0: 
goetz@7515: // Make the user specific temporary directory. Returns true if
aoqi@0: // the directory exists and is secure upon return. Returns false
aoqi@0: // if the directory exists but is either a symlink, is otherwise
aoqi@0: // insecure, or if an error occurred.
aoqi@0: static bool make_user_tmp_dir(const char* dirname) {
aoqi@0: 
goetz@7515:   // Create the directory with 0755 permissions. note that the directory
aoqi@0:   // will be owned by euid::egid, which may not be the same as uid::gid.
aoqi@0:   if (mkdir(dirname, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) == OS_ERR) {
aoqi@0:     if (errno == EEXIST) {
aoqi@0:       // The directory already exists and was probably created by another
aoqi@0:       // JVM instance. However, this could also be the result of a
aoqi@0:       // deliberate symlink. Verify that the existing directory is safe.
aoqi@0:       if (!is_directory_secure(dirname)) {
goetz@7515:         // Directory is not secure.
aoqi@0:         if (PrintMiscellaneous && Verbose) {
aoqi@0:           warning("%s directory is insecure\n", dirname);
aoqi@0:         }
aoqi@0:         return false;
aoqi@0:       }
aoqi@0:     }
aoqi@0:     else {
aoqi@0:       // we encountered some other failure while attempting
aoqi@0:       // to create the directory
aoqi@0:       //
aoqi@0:       if (PrintMiscellaneous && Verbose) {
aoqi@0:         warning("could not create directory %s: %s\n",
aoqi@0:                 dirname, strerror(errno));
aoqi@0:       }
aoqi@0:       return false;
aoqi@0:     }
aoqi@0:   }
aoqi@0:   return true;
aoqi@0: }
aoqi@0: 
aoqi@0: // create the shared memory file resources
aoqi@0: //
aoqi@0: // This method creates the shared memory file with the given size
aoqi@0: // This method also creates the user specific temporary directory, if
aoqi@0: // it does not yet exist.
aoqi@0: //
aoqi@0: static int create_sharedmem_resources(const char* dirname, const char* filename, size_t size) {
aoqi@0: 
aoqi@0:   // make the user temporary directory
aoqi@0:   if (!make_user_tmp_dir(dirname)) {
aoqi@0:     // could not make/find the directory or the found directory
aoqi@0:     // was not secure
aoqi@0:     return -1;
aoqi@0:   }
aoqi@0: 
goetz@7515:   int saved_cwd_fd;
goetz@7515:   // Open the directory and set the current working directory to it.
goetz@7515:   DIR* dirp = open_directory_secure_cwd(dirname, &saved_cwd_fd);
goetz@7515:   if (dirp == NULL) {
goetz@7515:     // Directory doesn't exist or is insecure, so cannot create shared
goetz@7515:     // memory file.
goetz@7515:     return -1;
goetz@7515:   }
goetz@7515: 
goetz@7515:   // Open the filename in the current directory.
goetz@7515:   // Cannot use O_TRUNC here; truncation of an existing file has to happen
goetz@7515:   // after the is_file_secure() check below.
aoqi@0:   int result;
aoqi@0: 
goetz@7515:   // No O_NOFOLLOW defined at buildtime, and it is not documented for open;
goetz@7515:   // so provide a workaround in this case.
goetz@7515: #ifdef O_NOFOLLOW
goetz@7515:   RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_NOFOLLOW, S_IREAD|S_IWRITE), result);
goetz@7515: #else
goetz@7515:   // workaround function (jdk6 code)
goetz@7515:   RESTARTABLE(::open_o_nofollow(filename, O_RDWR|O_CREAT, S_IREAD|S_IWRITE), result);
goetz@7515: #endif
goetz@7515: 
aoqi@0:   if (result == OS_ERR) {
aoqi@0:     if (PrintMiscellaneous && Verbose) {
goetz@7515:       if (errno == ELOOP) {
goetz@7515:         warning("file %s is a symlink and is not secure\n", filename);
goetz@7515:       } else {
goetz@7515:         warning("could not create file %s: %s\n", filename, strerror(errno));
goetz@7515:       }
aoqi@0:     }
goetz@7515:     // Close the directory and reset the current working directory.
goetz@7515:     close_directory_secure_cwd(dirp, saved_cwd_fd);
goetz@7515: 
aoqi@0:     return -1;
aoqi@0:   }
goetz@7515:   // Close the directory and reset the current working directory.
goetz@7515:   close_directory_secure_cwd(dirp, saved_cwd_fd);
aoqi@0: 
aoqi@0:   // save the file descriptor
aoqi@0:   int fd = result;
aoqi@0: 
goetz@7515:   // Check to see if the file is secure.
goetz@7515:   if (!is_file_secure(fd, filename)) {
goetz@7515:     ::close(fd);
goetz@7515:     return -1;
goetz@7515:   }
goetz@7515: 
goetz@7515:   // Truncate the file to get rid of any existing data.
goetz@7515:   RESTARTABLE(::ftruncate(fd, (off_t)0), result);
goetz@7515:   if (result == OS_ERR) {
goetz@7515:     if (PrintMiscellaneous && Verbose) {
goetz@7515:       warning("could not truncate shared memory file: %s\n", strerror(errno));
goetz@7515:     }
goetz@7515:     ::close(fd);
goetz@7515:     return -1;
goetz@7515:   }
aoqi@0:   // set the file size
aoqi@0:   RESTARTABLE(::ftruncate(fd, (off_t)size), result);
aoqi@0:   if (result == OS_ERR) {
aoqi@0:     if (PrintMiscellaneous && Verbose) {
aoqi@0:       warning("could not set shared memory file size: %s\n", strerror(errno));
aoqi@0:     }
aoqi@0:     RESTARTABLE(::close(fd), result);
aoqi@0:     return -1;
aoqi@0:   }
aoqi@0: 
aoqi@0:   return fd;
aoqi@0: }
aoqi@0: 
aoqi@0: // open the shared memory file for the given user and vmid. returns
aoqi@0: // the file descriptor for the open file or -1 if the file could not
aoqi@0: // be opened.
aoqi@0: //
aoqi@0: static int open_sharedmem_file(const char* filename, int oflags, TRAPS) {
aoqi@0: 
aoqi@0:   // open the file
aoqi@0:   int result;
goetz@7515:   // No O_NOFOLLOW defined at buildtime, and it is not documented for open;
goetz@7515:   // so provide a workaround in this case
goetz@7515: #ifdef O_NOFOLLOW
aoqi@0:   RESTARTABLE(::open(filename, oflags), result);
goetz@7515: #else
goetz@7515:   RESTARTABLE(::open_o_nofollow(filename, oflags), result);
goetz@7515: #endif
goetz@7515: 
aoqi@0:   if (result == OS_ERR) {
aoqi@0:     if (errno == ENOENT) {
aoqi@0:       THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
aoqi@0:                   "Process not found");
aoqi@0:     }
aoqi@0:     else if (errno == EACCES) {
aoqi@0:       THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
aoqi@0:                   "Permission denied");
aoqi@0:     }
aoqi@0:     else {
aoqi@0:       THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
aoqi@0:     }
aoqi@0:   }
goetz@7515:   int fd = result;
aoqi@0: 
goetz@7515:   // Check to see if the file is secure.
goetz@7515:   if (!is_file_secure(fd, filename)) {
goetz@7515:     ::close(fd);
goetz@7515:     return -1;
goetz@7515:   }
goetz@7515: 
goetz@7515:   return fd;
aoqi@0: }
aoqi@0: 
aoqi@0: // create a named shared memory region. returns the address of the
aoqi@0: // memory region on success or NULL on failure. A return value of
aoqi@0: // NULL will ultimately disable the shared memory feature.
aoqi@0: //
aoqi@0: // On Solaris and Linux, the name space for shared memory objects
aoqi@0: // is the file system name space.
aoqi@0: //
aoqi@0: // A monitoring application attaching to a JVM does not need to know
aoqi@0: // the file system name of the shared memory object. However, it may
aoqi@0: // be convenient for applications to discover the existence of newly
aoqi@0: // created and terminating JVMs by watching the file system name space
aoqi@0: // for files being created or removed.
aoqi@0: //
aoqi@0: static char* mmap_create_shared(size_t size) {
aoqi@0: 
aoqi@0:   int result;
aoqi@0:   int fd;
aoqi@0:   char* mapAddress;
aoqi@0: 
aoqi@0:   int vmid = os::current_process_id();
aoqi@0: 
aoqi@0:   char* user_name = get_user_name(geteuid());
aoqi@0: 
aoqi@0:   if (user_name == NULL)
aoqi@0:     return NULL;
aoqi@0: 
aoqi@0:   char* dirname = get_user_tmp_dir(user_name);
aoqi@0:   char* filename = get_sharedmem_filename(dirname, vmid);
aoqi@0: 
goetz@7515:   // Get the short filename.
goetz@7515:   char* short_filename = strrchr(filename, '/');
goetz@7515:   if (short_filename == NULL) {
goetz@7515:     short_filename = filename;
goetz@7515:   } else {
goetz@7515:     short_filename++;
goetz@7515:   }
goetz@7515: 
aoqi@0:   // cleanup any stale shared memory files
aoqi@0:   cleanup_sharedmem_resources(dirname);
aoqi@0: 
aoqi@0:   assert(((size > 0) && (size % os::vm_page_size() == 0)),
aoqi@0:          "unexpected PerfMemory region size");
aoqi@0: 
goetz@7515:   fd = create_sharedmem_resources(dirname, short_filename, size);
aoqi@0: 
aoqi@0:   FREE_C_HEAP_ARRAY(char, user_name, mtInternal);
aoqi@0:   FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
aoqi@0: 
aoqi@0:   if (fd == -1) {
aoqi@0:     FREE_C_HEAP_ARRAY(char, filename, mtInternal);
aoqi@0:     return NULL;
aoqi@0:   }
aoqi@0: 
aoqi@0:   mapAddress = (char*)::mmap((char*)0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
aoqi@0: 
aoqi@0:   // attempt to close the file - restart it if it was interrupted,
aoqi@0:   // but ignore other failures
aoqi@0:   RESTARTABLE(::close(fd), result);
aoqi@0:   assert(result != OS_ERR, "could not close file");
aoqi@0: 
aoqi@0:   if (mapAddress == MAP_FAILED) {
aoqi@0:     if (PrintMiscellaneous && Verbose) {
aoqi@0:       warning("mmap failed -  %s\n", strerror(errno));
aoqi@0:     }
aoqi@0:     remove_file(filename);
aoqi@0:     FREE_C_HEAP_ARRAY(char, filename, mtInternal);
aoqi@0:     return NULL;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // save the file name for use in delete_shared_memory()
aoqi@0:   backing_store_file_name = filename;
aoqi@0: 
aoqi@0:   // clear the shared memory region
aoqi@0:   (void)::memset((void*) mapAddress, 0, size);
aoqi@0: 
goetz@7515:   // It does not go through os api, the operation has to record from here.
goetz@7515:   MemTracker::record_virtual_memory_reserve((address)mapAddress, size, CURRENT_PC, mtInternal);
goetz@7515: 
aoqi@0:   return mapAddress;
aoqi@0: }
aoqi@0: 
aoqi@0: // release a named shared memory region
aoqi@0: //
aoqi@0: static void unmap_shared(char* addr, size_t bytes) {
aoqi@0:   // Do not rely on os::reserve_memory/os::release_memory to use mmap.
aoqi@0:   // Use os::reserve_memory/os::release_memory for PerfDisableSharedMem=1, mmap/munmap for PerfDisableSharedMem=0
aoqi@0:   if (::munmap(addr, bytes) == -1) {
aoqi@0:     warning("perfmemory: munmap failed (%d)\n", errno);
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: // create the PerfData memory region in shared memory.
aoqi@0: //
aoqi@0: static char* create_shared_memory(size_t size) {
aoqi@0: 
aoqi@0:   // create the shared memory region.
aoqi@0:   return mmap_create_shared(size);
aoqi@0: }
aoqi@0: 
aoqi@0: // delete the shared PerfData memory region
aoqi@0: //
aoqi@0: static void delete_shared_memory(char* addr, size_t size) {
aoqi@0: 
aoqi@0:   // cleanup the persistent shared memory resources. since DestroyJavaVM does
aoqi@0:   // not support unloading of the JVM, unmapping of the memory resource is
aoqi@0:   // not performed. The memory will be reclaimed by the OS upon termination of
aoqi@0:   // the process. The backing store file is deleted from the file system.
aoqi@0: 
aoqi@0:   assert(!PerfDisableSharedMem, "shouldn't be here");
aoqi@0: 
aoqi@0:   if (backing_store_file_name != NULL) {
aoqi@0:     remove_file(backing_store_file_name);
aoqi@0:     // Don't.. Free heap memory could deadlock os::abort() if it is called
aoqi@0:     // from signal handler. OS will reclaim the heap memory.
aoqi@0:     // FREE_C_HEAP_ARRAY(char, backing_store_file_name, mtInternal);
aoqi@0:     backing_store_file_name = NULL;
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: // return the size of the file for the given file descriptor
aoqi@0: // or 0 if it is not a valid size for a shared memory file
aoqi@0: //
aoqi@0: static size_t sharedmem_filesize(int fd, TRAPS) {
aoqi@0: 
aoqi@0:   struct stat statbuf;
aoqi@0:   int result;
aoqi@0: 
aoqi@0:   RESTARTABLE(::fstat(fd, &statbuf), result);
aoqi@0:   if (result == OS_ERR) {
aoqi@0:     if (PrintMiscellaneous && Verbose) {
aoqi@0:       warning("fstat failed: %s\n", strerror(errno));
aoqi@0:     }
aoqi@0:     THROW_MSG_0(vmSymbols::java_io_IOException(),
aoqi@0:                 "Could not determine PerfMemory size");
aoqi@0:   }
aoqi@0: 
aoqi@0:   if ((statbuf.st_size == 0) ||
aoqi@0:      ((size_t)statbuf.st_size % os::vm_page_size() != 0)) {
aoqi@0:     THROW_MSG_0(vmSymbols::java_lang_Exception(),
aoqi@0:                 "Invalid PerfMemory size");
aoqi@0:   }
aoqi@0: 
aoqi@0:   return (size_t)statbuf.st_size;
aoqi@0: }
aoqi@0: 
aoqi@0: // attach to a named shared memory region.
aoqi@0: //
aoqi@0: static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemoryMode mode, char** addr, size_t* sizep, TRAPS) {
aoqi@0: 
aoqi@0:   char* mapAddress;
aoqi@0:   int result;
aoqi@0:   int fd;
goetz@7515:   size_t size = 0;
aoqi@0:   const char* luser = NULL;
aoqi@0: 
aoqi@0:   int mmap_prot;
aoqi@0:   int file_flags;
aoqi@0: 
aoqi@0:   ResourceMark rm;
aoqi@0: 
aoqi@0:   // map the high level access mode to the appropriate permission
aoqi@0:   // constructs for the file and the shared memory mapping.
aoqi@0:   if (mode == PerfMemory::PERF_MODE_RO) {
aoqi@0:     mmap_prot = PROT_READ;
goetz@7515: 
goetz@7515:   // No O_NOFOLLOW defined at buildtime, and it is not documented for open.
goetz@7515: #ifdef O_NOFOLLOW
goetz@7515:     file_flags = O_RDONLY | O_NOFOLLOW;
goetz@7515: #else
aoqi@0:     file_flags = O_RDONLY;
goetz@7515: #endif
aoqi@0:   }
aoqi@0:   else if (mode == PerfMemory::PERF_MODE_RW) {
aoqi@0: #ifdef LATER
aoqi@0:     mmap_prot = PROT_READ | PROT_WRITE;
goetz@7515:     file_flags = O_RDWR | O_NOFOLLOW;
aoqi@0: #else
aoqi@0:     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
aoqi@0:               "Unsupported access mode");
aoqi@0: #endif
aoqi@0:   }
aoqi@0:   else {
aoqi@0:     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
aoqi@0:               "Illegal access mode");
aoqi@0:   }
aoqi@0: 
aoqi@0:   if (user == NULL || strlen(user) == 0) {
aoqi@0:     luser = get_user_name(vmid, CHECK);
aoqi@0:   }
aoqi@0:   else {
aoqi@0:     luser = user;
aoqi@0:   }
aoqi@0: 
aoqi@0:   if (luser == NULL) {
aoqi@0:     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
aoqi@0:               "Could not map vmid to user Name");
aoqi@0:   }
aoqi@0: 
aoqi@0:   char* dirname = get_user_tmp_dir(luser);
aoqi@0: 
aoqi@0:   // since we don't follow symbolic links when creating the backing
aoqi@0:   // store file, we don't follow them when attaching either.
aoqi@0:   //
aoqi@0:   if (!is_directory_secure(dirname)) {
aoqi@0:     FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
goetz@7515:     if (luser != user) {
goetz@7515:       FREE_C_HEAP_ARRAY(char, luser, mtInternal);
goetz@7515:     }
aoqi@0:     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
aoqi@0:               "Process not found");
aoqi@0:   }
aoqi@0: 
aoqi@0:   char* filename = get_sharedmem_filename(dirname, vmid);
aoqi@0: 
aoqi@0:   // copy heap memory to resource memory. the open_sharedmem_file
aoqi@0:   // method below need to use the filename, but could throw an
aoqi@0:   // exception. using a resource array prevents the leak that
aoqi@0:   // would otherwise occur.
aoqi@0:   char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
aoqi@0:   strcpy(rfilename, filename);
aoqi@0: 
aoqi@0:   // free the c heap resources that are no longer needed
aoqi@0:   if (luser != user) FREE_C_HEAP_ARRAY(char, luser, mtInternal);
aoqi@0:   FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
aoqi@0:   FREE_C_HEAP_ARRAY(char, filename, mtInternal);
aoqi@0: 
aoqi@0:   // open the shared memory file for the give vmid
aoqi@0:   fd = open_sharedmem_file(rfilename, file_flags, CHECK);
aoqi@0:   assert(fd != OS_ERR, "unexpected value");
aoqi@0: 
aoqi@0:   if (*sizep == 0) {
aoqi@0:     size = sharedmem_filesize(fd, CHECK);
aoqi@0:     assert(size != 0, "unexpected size");
aoqi@0:   } else {
aoqi@0:     size = *sizep;
aoqi@0:   }
aoqi@0: 
aoqi@0:   mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0);
aoqi@0: 
aoqi@0:   // attempt to close the file - restart if it gets interrupted,
aoqi@0:   // but ignore other failures
aoqi@0:   RESTARTABLE(::close(fd), result);
aoqi@0:   assert(result != OS_ERR, "could not close file");
aoqi@0: 
aoqi@0:   if (mapAddress == MAP_FAILED) {
aoqi@0:     if (PrintMiscellaneous && Verbose) {
aoqi@0:       warning("mmap failed: %s\n", strerror(errno));
aoqi@0:     }
aoqi@0:     THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
aoqi@0:               "Could not map PerfMemory");
aoqi@0:   }
aoqi@0: 
goetz@7515:   // It does not go through os api, the operation has to record from here.
goetz@7515:   MemTracker::record_virtual_memory_reserve((address)mapAddress, size, CURRENT_PC, mtInternal);
goetz@7515: 
aoqi@0:   *addr = mapAddress;
aoqi@0:   *sizep = size;
aoqi@0: 
aoqi@0:   if (PerfTraceMemOps) {
aoqi@0:     tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at "
aoqi@0:                INTPTR_FORMAT "\n", size, vmid, (void*)mapAddress);
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: 
aoqi@0: 
aoqi@0: // create the PerfData memory region
aoqi@0: //
aoqi@0: // This method creates the memory region used to store performance
aoqi@0: // data for the JVM. The memory may be created in standard or
aoqi@0: // shared memory.
aoqi@0: //
aoqi@0: void PerfMemory::create_memory_region(size_t size) {
aoqi@0: 
aoqi@0:   if (PerfDisableSharedMem) {
aoqi@0:     // do not share the memory for the performance data.
aoqi@0:     _start = create_standard_memory(size);
aoqi@0:   }
aoqi@0:   else {
aoqi@0:     _start = create_shared_memory(size);
aoqi@0:     if (_start == NULL) {
aoqi@0: 
aoqi@0:       // creation of the shared memory region failed, attempt
aoqi@0:       // to create a contiguous, non-shared memory region instead.
aoqi@0:       //
aoqi@0:       if (PrintMiscellaneous && Verbose) {
aoqi@0:         warning("Reverting to non-shared PerfMemory region.\n");
aoqi@0:       }
aoqi@0:       PerfDisableSharedMem = true;
aoqi@0:       _start = create_standard_memory(size);
aoqi@0:     }
aoqi@0:   }
aoqi@0: 
aoqi@0:   if (_start != NULL) _capacity = size;
aoqi@0: 
aoqi@0: }
aoqi@0: 
aoqi@0: // delete the PerfData memory region
aoqi@0: //
aoqi@0: // This method deletes the memory region used to store performance
aoqi@0: // data for the JVM. The memory region indicated by the <address, size>
aoqi@0: // tuple will be inaccessible after a call to this method.
aoqi@0: //
aoqi@0: void PerfMemory::delete_memory_region() {
aoqi@0: 
aoqi@0:   assert((start() != NULL && capacity() > 0), "verify proper state");
aoqi@0: 
aoqi@0:   // If user specifies PerfDataSaveFile, it will save the performance data
aoqi@0:   // to the specified file name no matter whether PerfDataSaveToFile is specified
aoqi@0:   // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
aoqi@0:   // -XX:+PerfDataSaveToFile.
aoqi@0:   if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
aoqi@0:     save_memory_to_file(start(), capacity());
aoqi@0:   }
aoqi@0: 
aoqi@0:   if (PerfDisableSharedMem) {
aoqi@0:     delete_standard_memory(start(), capacity());
aoqi@0:   }
aoqi@0:   else {
aoqi@0:     delete_shared_memory(start(), capacity());
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: // attach to the PerfData memory region for another JVM
aoqi@0: //
aoqi@0: // This method returns an <address, size> tuple that points to
aoqi@0: // a memory buffer that is kept reasonably synchronized with
aoqi@0: // the PerfData memory region for the indicated JVM. This
aoqi@0: // buffer may be kept in synchronization via shared memory
aoqi@0: // or some other mechanism that keeps the buffer updated.
aoqi@0: //
aoqi@0: // If the JVM chooses not to support the attachability feature,
aoqi@0: // this method should throw an UnsupportedOperation exception.
aoqi@0: //
aoqi@0: // This implementation utilizes named shared memory to map
aoqi@0: // the indicated process's PerfData memory region into this JVMs
aoqi@0: // address space.
aoqi@0: //
aoqi@0: void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, char** addrp, size_t* sizep, TRAPS) {
aoqi@0: 
aoqi@0:   if (vmid == 0 || vmid == os::current_process_id()) {
aoqi@0:      *addrp = start();
aoqi@0:      *sizep = capacity();
aoqi@0:      return;
aoqi@0:   }
aoqi@0: 
aoqi@0:   mmap_attach_shared(user, vmid, mode, addrp, sizep, CHECK);
aoqi@0: }
aoqi@0: 
aoqi@0: // detach from the PerfData memory region of another JVM
aoqi@0: //
aoqi@0: // This method detaches the PerfData memory region of another
aoqi@0: // JVM, specified as an <address, size> tuple of a buffer
aoqi@0: // in this process's address space. This method may perform
aoqi@0: // arbitrary actions to accomplish the detachment. The memory
aoqi@0: // region specified by <address, size> will be inaccessible after
aoqi@0: // a call to this method.
aoqi@0: //
aoqi@0: // If the JVM chooses not to support the attachability feature,
aoqi@0: // this method should throw an UnsupportedOperation exception.
aoqi@0: //
aoqi@0: // This implementation utilizes named shared memory to detach
aoqi@0: // the indicated process's PerfData memory region from this
aoqi@0: // process's address space.
aoqi@0: //
aoqi@0: void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
aoqi@0: 
aoqi@0:   assert(addr != 0, "address sanity check");
aoqi@0:   assert(bytes > 0, "capacity sanity check");
aoqi@0: 
aoqi@0:   if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
aoqi@0:     // prevent accidental detachment of this process's PerfMemory region
aoqi@0:     return;
aoqi@0:   }
aoqi@0: 
aoqi@0:   unmap_shared(addr, bytes);
aoqi@0: }
aoqi@0: 
aoqi@0: char* PerfMemory::backing_store_filename() {
aoqi@0:   return backing_store_file_name;
aoqi@0: }