never@3156: /*
never@3156:  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
never@3156:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
never@3156:  *
never@3156:  * This code is free software; you can redistribute it and/or modify it
never@3156:  * under the terms of the GNU General Public License version 2 only, as
never@3156:  * published by the Free Software Foundation.
never@3156:  *
never@3156:  * This code is distributed in the hope that it will be useful, but WITHOUT
never@3156:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
never@3156:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
never@3156:  * version 2 for more details (a copy is included in the LICENSE file that
never@3156:  * accompanied this code).
never@3156:  *
never@3156:  * You should have received a copy of the GNU General Public License version
never@3156:  * 2 along with this work; if not, write to the Free Software Foundation,
never@3156:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
never@3156:  *
never@3156:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
never@3156:  * or visit www.oracle.com if you need additional information or have any
never@3156:  * questions.
never@3156:  *
never@3156:  */
never@3156: 
never@3156: #include "precompiled.hpp"
never@3156: #include "classfile/vmSymbols.hpp"
never@3156: #include "memory/allocation.inline.hpp"
never@3156: #include "memory/resourceArea.hpp"
never@3156: #include "oops/oop.inline.hpp"
never@3156: #include "os_bsd.inline.hpp"
never@3156: #include "runtime/handles.inline.hpp"
never@3156: #include "runtime/perfMemory.hpp"
never@3156: #include "utilities/exceptions.hpp"
never@3156: 
never@3156: // put OS-includes here
never@3156: # include <sys/types.h>
never@3156: # include <sys/mman.h>
never@3156: # include <errno.h>
never@3156: # include <stdio.h>
never@3156: # include <unistd.h>
never@3156: # include <sys/stat.h>
never@3156: # include <signal.h>
never@3156: # include <pwd.h>
never@3156: 
never@3156: static char* backing_store_file_name = NULL;  // name of the backing store
never@3156:                                               // file, if successfully created.
never@3156: 
never@3156: // Standard Memory Implementation Details
never@3156: 
never@3156: // create the PerfData memory region in standard memory.
never@3156: //
never@3156: static char* create_standard_memory(size_t size) {
never@3156: 
never@3156:   // allocate an aligned chuck of memory
never@3156:   char* mapAddress = os::reserve_memory(size);
never@3156: 
never@3156:   if (mapAddress == NULL) {
never@3156:     return NULL;
never@3156:   }
never@3156: 
never@3156:   // commit memory
never@3156:   if (!os::commit_memory(mapAddress, size)) {
never@3156:     if (PrintMiscellaneous && Verbose) {
never@3156:       warning("Could not commit PerfData memory\n");
never@3156:     }
never@3156:     os::release_memory(mapAddress, size);
never@3156:     return NULL;
never@3156:   }
never@3156: 
never@3156:   return mapAddress;
never@3156: }
never@3156: 
never@3156: // delete the PerfData memory region
never@3156: //
never@3156: static void delete_standard_memory(char* addr, size_t size) {
never@3156: 
never@3156:   // there are no persistent external resources to cleanup for standard
never@3156:   // memory. since DestroyJavaVM does not support unloading of the JVM,
never@3156:   // cleanup of the memory resource is not performed. The memory will be
never@3156:   // reclaimed by the OS upon termination of the process.
never@3156:   //
never@3156:   return;
never@3156: }
never@3156: 
never@3156: // save the specified memory region to the given file
never@3156: //
never@3156: // Note: this function might be called from signal handler (by os::abort()),
never@3156: // don't allocate heap memory.
never@3156: //
never@3156: static void save_memory_to_file(char* addr, size_t size) {
never@3156: 
never@3156:  const char* destfile = PerfMemory::get_perfdata_file_path();
never@3156:  assert(destfile[0] != '\0', "invalid PerfData file path");
never@3156: 
never@3156:   int result;
never@3156: 
never@3156:   RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE),
never@3156:               result);;
never@3156:   if (result == OS_ERR) {
never@3156:     if (PrintMiscellaneous && Verbose) {
never@3156:       warning("Could not create Perfdata save file: %s: %s\n",
never@3156:               destfile, strerror(errno));
never@3156:     }
never@3156:   } else {
never@3156:     int fd = result;
never@3156: 
never@3156:     for (size_t remaining = size; remaining > 0;) {
never@3156: 
never@3156:       RESTARTABLE(::write(fd, addr, remaining), result);
never@3156:       if (result == OS_ERR) {
never@3156:         if (PrintMiscellaneous && Verbose) {
never@3156:           warning("Could not write Perfdata save file: %s: %s\n",
never@3156:                   destfile, strerror(errno));
never@3156:         }
never@3156:         break;
never@3156:       }
never@3156: 
never@3156:       remaining -= (size_t)result;
never@3156:       addr += result;
never@3156:     }
never@3156: 
never@3156:     RESTARTABLE(::close(fd), result);
never@3156:     if (PrintMiscellaneous && Verbose) {
never@3156:       if (result == OS_ERR) {
never@3156:         warning("Could not close %s: %s\n", destfile, strerror(errno));
never@3156:       }
never@3156:     }
never@3156:   }
zgu@3900:   FREE_C_HEAP_ARRAY(char, destfile, mtInternal);
never@3156: }
never@3156: 
never@3156: 
never@3156: // Shared Memory Implementation Details
never@3156: 
never@3156: // Note: the solaris and bsd shared memory implementation uses the mmap
never@3156: // interface with a backing store file to implement named shared memory.
never@3156: // Using the file system as the name space for shared memory allows a
never@3156: // common name space to be supported across a variety of platforms. It
never@3156: // also provides a name space that Java applications can deal with through
never@3156: // simple file apis.
never@3156: //
never@3156: // The solaris and bsd implementations store the backing store file in
never@3156: // a user specific temporary directory located in the /tmp file system,
never@3156: // which is always a local file system and is sometimes a RAM based file
never@3156: // system.
never@3156: 
never@3156: // return the user specific temporary directory name.
never@3156: //
never@3156: // the caller is expected to free the allocated memory.
never@3156: //
never@3156: static char* get_user_tmp_dir(const char* user) {
never@3156: 
never@3156:   const char* tmpdir = os::get_temp_directory();
never@3156:   const char* perfdir = PERFDATA_NAME;
never@3156:   size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3;
zgu@3900:   char* dirname = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
never@3156: 
never@3156:   // construct the path name to user specific tmp directory
never@3156:   snprintf(dirname, nbytes, "%s/%s_%s", tmpdir, perfdir, user);
never@3156: 
never@3156:   return dirname;
never@3156: }
never@3156: 
never@3156: // convert the given file name into a process id. if the file
never@3156: // does not meet the file naming constraints, return 0.
never@3156: //
never@3156: static pid_t filename_to_pid(const char* filename) {
never@3156: 
never@3156:   // a filename that doesn't begin with a digit is not a
never@3156:   // candidate for conversion.
never@3156:   //
never@3156:   if (!isdigit(*filename)) {
never@3156:     return 0;
never@3156:   }
never@3156: 
never@3156:   // check if file name can be converted to an integer without
never@3156:   // any leftover characters.
never@3156:   //
never@3156:   char* remainder = NULL;
never@3156:   errno = 0;
never@3156:   pid_t pid = (pid_t)strtol(filename, &remainder, 10);
never@3156: 
never@3156:   if (errno != 0) {
never@3156:     return 0;
never@3156:   }
never@3156: 
never@3156:   // check for left over characters. If any, then the filename is
never@3156:   // not a candidate for conversion.
never@3156:   //
never@3156:   if (remainder != NULL && *remainder != '\0') {
never@3156:     return 0;
never@3156:   }
never@3156: 
never@3156:   // successful conversion, return the pid
never@3156:   return pid;
never@3156: }
never@3156: 
never@3156: 
never@3156: // check if the given path is considered a secure directory for
never@3156: // the backing store files. Returns true if the directory exists
never@3156: // and is considered a secure location. Returns false if the path
never@3156: // is a symbolic link or if an error occurred.
never@3156: //
never@3156: static bool is_directory_secure(const char* path) {
never@3156:   struct stat statbuf;
never@3156:   int result = 0;
never@3156: 
never@3156:   RESTARTABLE(::lstat(path, &statbuf), result);
never@3156:   if (result == OS_ERR) {
never@3156:     return false;
never@3156:   }
never@3156: 
never@3156:   // the path exists, now check it's mode
never@3156:   if (S_ISLNK(statbuf.st_mode) || !S_ISDIR(statbuf.st_mode)) {
never@3156:     // the path represents a link or some non-directory file type,
never@3156:     // which is not what we expected. declare it insecure.
never@3156:     //
never@3156:     return false;
never@3156:   }
never@3156:   else {
never@3156:     // we have an existing directory, check if the permissions are safe.
never@3156:     //
never@3156:     if ((statbuf.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
never@3156:       // the directory is open for writing and could be subjected
never@3156:       // to a symlnk attack. declare it insecure.
never@3156:       //
never@3156:       return false;
never@3156:     }
never@3156:   }
never@3156:   return true;
never@3156: }
never@3156: 
never@3156: 
never@3156: // return the user name for the given user id
never@3156: //
never@3156: // the caller is expected to free the allocated memory.
never@3156: //
never@3156: static char* get_user_name(uid_t uid) {
never@3156: 
never@3156:   struct passwd pwent;
never@3156: 
never@3156:   // determine the max pwbuf size from sysconf, and hardcode
never@3156:   // a default if this not available through sysconf.
never@3156:   //
never@3156:   long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
never@3156:   if (bufsize == -1)
never@3156:     bufsize = 1024;
never@3156: 
zgu@3900:   char* pwbuf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
never@3156: 
never@3156:   // POSIX interface to getpwuid_r is used on LINUX
never@3156:   struct passwd* p;
never@3156:   int result = getpwuid_r(uid, &pwent, pwbuf, (size_t)bufsize, &p);
never@3156: 
never@3156:   if (result != 0 || p == NULL || p->pw_name == NULL || *(p->pw_name) == '\0') {
never@3156:     if (PrintMiscellaneous && Verbose) {
never@3156:       if (result != 0) {
never@3156:         warning("Could not retrieve passwd entry: %s\n",
never@3156:                 strerror(result));
never@3156:       }
never@3156:       else if (p == NULL) {
never@3156:         // this check is added to protect against an observed problem
never@3156:         // with getpwuid_r() on RedHat 9 where getpwuid_r returns 0,
never@3156:         // indicating success, but has p == NULL. This was observed when
never@3156:         // inserting a file descriptor exhaustion fault prior to the call
never@3156:         // getpwuid_r() call. In this case, error is set to the appropriate
never@3156:         // error condition, but this is undocumented behavior. This check
never@3156:         // is safe under any condition, but the use of errno in the output
never@3156:         // message may result in an erroneous message.
never@3156:         // Bug Id 89052 was opened with RedHat.
never@3156:         //
never@3156:         warning("Could not retrieve passwd entry: %s\n",
never@3156:                 strerror(errno));
never@3156:       }
never@3156:       else {
never@3156:         warning("Could not determine user name: %s\n",
never@3156:                 p->pw_name == NULL ? "pw_name = NULL" :
never@3156:                                      "pw_name zero length");
never@3156:       }
never@3156:     }
zgu@3900:     FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal);
never@3156:     return NULL;
never@3156:   }
never@3156: 
zgu@3900:   char* user_name = NEW_C_HEAP_ARRAY(char, strlen(p->pw_name) + 1, mtInternal);
never@3156:   strcpy(user_name, p->pw_name);
never@3156: 
zgu@3900:   FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal);
never@3156:   return user_name;
never@3156: }
never@3156: 
never@3156: // return the name of the user that owns the process identified by vmid.
never@3156: //
never@3156: // This method uses a slow directory search algorithm to find the backing
never@3156: // store file for the specified vmid and returns the user name, as determined
never@3156: // by the user name suffix of the hsperfdata_<username> directory name.
never@3156: //
never@3156: // the caller is expected to free the allocated memory.
never@3156: //
never@3156: static char* get_user_name_slow(int vmid, TRAPS) {
never@3156: 
never@3156:   // short circuit the directory search if the process doesn't even exist.
never@3156:   if (kill(vmid, 0) == OS_ERR) {
never@3156:     if (errno == ESRCH) {
never@3156:       THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
never@3156:                   "Process not found");
never@3156:     }
never@3156:     else /* EPERM */ {
never@3156:       THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
never@3156:     }
never@3156:   }
never@3156: 
never@3156:   // directory search
never@3156:   char* oldest_user = NULL;
never@3156:   time_t oldest_ctime = 0;
never@3156: 
never@3156:   const char* tmpdirname = os::get_temp_directory();
never@3156: 
never@3156:   DIR* tmpdirp = os::opendir(tmpdirname);
never@3156: 
never@3156:   if (tmpdirp == NULL) {
never@3156:     return NULL;
never@3156:   }
never@3156: 
never@3156:   // for each entry in the directory that matches the pattern hsperfdata_*,
never@3156:   // open the directory and check if the file for the given vmid exists.
never@3156:   // The file with the expected name and the latest creation date is used
never@3156:   // to determine the user name for the process id.
never@3156:   //
never@3156:   struct dirent* dentry;
zgu@3900:   char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname), mtInternal);
never@3156:   errno = 0;
never@3156:   while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) {
never@3156: 
never@3156:     // check if the directory entry is a hsperfdata file
never@3156:     if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
never@3156:       continue;
never@3156:     }
never@3156: 
never@3156:     char* usrdir_name = NEW_C_HEAP_ARRAY(char,
zgu@3900:                  strlen(tmpdirname) + strlen(dentry->d_name) + 2, mtInternal);
never@3156:     strcpy(usrdir_name, tmpdirname);
never@3156:     strcat(usrdir_name, "/");
never@3156:     strcat(usrdir_name, dentry->d_name);
never@3156: 
never@3156:     DIR* subdirp = os::opendir(usrdir_name);
never@3156: 
never@3156:     if (subdirp == NULL) {
zgu@3900:       FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
never@3156:       continue;
never@3156:     }
never@3156: 
never@3156:     // Since we don't create the backing store files in directories
never@3156:     // pointed to by symbolic links, we also don't follow them when
never@3156:     // looking for the files. We check for a symbolic link after the
never@3156:     // call to opendir in order to eliminate a small window where the
never@3156:     // symlink can be exploited.
never@3156:     //
never@3156:     if (!is_directory_secure(usrdir_name)) {
zgu@3900:       FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
never@3156:       os::closedir(subdirp);
never@3156:       continue;
never@3156:     }
never@3156: 
never@3156:     struct dirent* udentry;
zgu@3900:     char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name), mtInternal);
never@3156:     errno = 0;
never@3156:     while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
never@3156: 
never@3156:       if (filename_to_pid(udentry->d_name) == vmid) {
never@3156:         struct stat statbuf;
never@3156:         int result;
never@3156: 
never@3156:         char* filename = NEW_C_HEAP_ARRAY(char,
zgu@3900:                  strlen(usrdir_name) + strlen(udentry->d_name) + 2, mtInternal);
never@3156: 
never@3156:         strcpy(filename, usrdir_name);
never@3156:         strcat(filename, "/");
never@3156:         strcat(filename, udentry->d_name);
never@3156: 
never@3156:         // don't follow symbolic links for the file
never@3156:         RESTARTABLE(::lstat(filename, &statbuf), result);
never@3156:         if (result == OS_ERR) {
zgu@3900:            FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156:            continue;
never@3156:         }
never@3156: 
never@3156:         // skip over files that are not regular files.
never@3156:         if (!S_ISREG(statbuf.st_mode)) {
zgu@3900:           FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156:           continue;
never@3156:         }
never@3156: 
never@3156:         // compare and save filename with latest creation time
never@3156:         if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) {
never@3156: 
never@3156:           if (statbuf.st_ctime > oldest_ctime) {
never@3156:             char* user = strchr(dentry->d_name, '_') + 1;
never@3156: 
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);
never@3156: 
never@3156:             strcpy(oldest_user, user);
never@3156:             oldest_ctime = statbuf.st_ctime;
never@3156:           }
never@3156:         }
never@3156: 
zgu@3900:         FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156:       }
never@3156:     }
never@3156:     os::closedir(subdirp);
zgu@3900:     FREE_C_HEAP_ARRAY(char, udbuf, mtInternal);
zgu@3900:     FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
never@3156:   }
never@3156:   os::closedir(tmpdirp);
zgu@3900:   FREE_C_HEAP_ARRAY(char, tdbuf, mtInternal);
never@3156: 
never@3156:   return(oldest_user);
never@3156: }
never@3156: 
never@3156: // return the name of the user that owns the JVM indicated by the given vmid.
never@3156: //
never@3156: static char* get_user_name(int vmid, TRAPS) {
never@3156:   return get_user_name_slow(vmid, CHECK_NULL);
never@3156: }
never@3156: 
never@3156: // return the file name of the backing store file for the named
never@3156: // shared memory region for the given user name and vmid.
never@3156: //
never@3156: // the caller is expected to free the allocated memory.
never@3156: //
never@3156: static char* get_sharedmem_filename(const char* dirname, int vmid) {
never@3156: 
never@3156:   // add 2 for the file separator and a null terminator.
never@3156:   size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
never@3156: 
zgu@3900:   char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
never@3156:   snprintf(name, nbytes, "%s/%d", dirname, vmid);
never@3156: 
never@3156:   return name;
never@3156: }
never@3156: 
never@3156: 
never@3156: // remove file
never@3156: //
never@3156: // this method removes the file specified by the given path
never@3156: //
never@3156: static void remove_file(const char* path) {
never@3156: 
never@3156:   int result;
never@3156: 
never@3156:   // if the file is a directory, the following unlink will fail. since
never@3156:   // we don't expect to find directories in the user temp directory, we
never@3156:   // won't try to handle this situation. even if accidentially or
never@3156:   // maliciously planted, the directory's presence won't hurt anything.
never@3156:   //
never@3156:   RESTARTABLE(::unlink(path), result);
never@3156:   if (PrintMiscellaneous && Verbose && result == OS_ERR) {
never@3156:     if (errno != ENOENT) {
never@3156:       warning("Could not unlink shared memory backing"
never@3156:               " store file %s : %s\n", path, strerror(errno));
never@3156:     }
never@3156:   }
never@3156: }
never@3156: 
never@3156: 
never@3156: // remove file
never@3156: //
never@3156: // this method removes the file with the given file name in the
never@3156: // named directory.
never@3156: //
never@3156: static void remove_file(const char* dirname, const char* filename) {
never@3156: 
never@3156:   size_t nbytes = strlen(dirname) + strlen(filename) + 2;
zgu@3900:   char* path = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal);
never@3156: 
never@3156:   strcpy(path, dirname);
never@3156:   strcat(path, "/");
never@3156:   strcat(path, filename);
never@3156: 
never@3156:   remove_file(path);
never@3156: 
zgu@3900:   FREE_C_HEAP_ARRAY(char, path, mtInternal);
never@3156: }
never@3156: 
never@3156: 
never@3156: // cleanup stale shared memory resources
never@3156: //
never@3156: // This method attempts to remove all stale shared memory files in
never@3156: // the named user temporary directory. It scans the named directory
never@3156: // for files matching the pattern ^$[0-9]*$. For each file found, the
never@3156: // process id is extracted from the file name and a test is run to
never@3156: // determine if the process is alive. If the process is not alive,
never@3156: // any stale file resources are removed.
never@3156: //
never@3156: static void cleanup_sharedmem_resources(const char* dirname) {
never@3156: 
never@3156:   // open the user temp directory
never@3156:   DIR* dirp = os::opendir(dirname);
never@3156: 
never@3156:   if (dirp == NULL) {
never@3156:     // directory doesn't exist, so there is nothing to cleanup
never@3156:     return;
never@3156:   }
never@3156: 
never@3156:   if (!is_directory_secure(dirname)) {
never@3156:     // the directory is not a secure directory
never@3156:     return;
never@3156:   }
never@3156: 
never@3156:   // for each entry in the directory that matches the expected file
never@3156:   // name pattern, determine if the file resources are stale and if
never@3156:   // so, remove the file resources. Note, instrumented HotSpot processes
never@3156:   // for this user may start and/or terminate during this search and
never@3156:   // remove or create new files in this directory. The behavior of this
never@3156:   // loop under these conditions is dependent upon the implementation of
never@3156:   // opendir/readdir.
never@3156:   //
never@3156:   struct dirent* entry;
zgu@3900:   char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname), mtInternal);
never@3156:   errno = 0;
never@3156:   while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) {
never@3156: 
never@3156:     pid_t pid = filename_to_pid(entry->d_name);
never@3156: 
never@3156:     if (pid == 0) {
never@3156: 
never@3156:       if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
never@3156: 
never@3156:         // attempt to remove all unexpected files, except "." and ".."
never@3156:         remove_file(dirname, entry->d_name);
never@3156:       }
never@3156: 
never@3156:       errno = 0;
never@3156:       continue;
never@3156:     }
never@3156: 
never@3156:     // we now have a file name that converts to a valid integer
never@3156:     // that could represent a process id . if this process id
never@3156:     // matches the current process id or the process is not running,
never@3156:     // then remove the stale file resources.
never@3156:     //
never@3156:     // process liveness is detected by sending signal number 0 to
never@3156:     // the process id (see kill(2)). if kill determines that the
never@3156:     // process does not exist, then the file resources are removed.
never@3156:     // if kill determines that that we don't have permission to
never@3156:     // signal the process, then the file resources are assumed to
never@3156:     // be stale and are removed because the resources for such a
never@3156:     // process should be in a different user specific directory.
never@3156:     //
never@3156:     if ((pid == os::current_process_id()) ||
never@3156:         (kill(pid, 0) == OS_ERR && (errno == ESRCH || errno == EPERM))) {
never@3156: 
never@3156:         remove_file(dirname, entry->d_name);
never@3156:     }
never@3156:     errno = 0;
never@3156:   }
never@3156:   os::closedir(dirp);
zgu@3900:   FREE_C_HEAP_ARRAY(char, dbuf, mtInternal);
never@3156: }
never@3156: 
never@3156: // make the user specific temporary directory. Returns true if
never@3156: // the directory exists and is secure upon return. Returns false
never@3156: // if the directory exists but is either a symlink, is otherwise
never@3156: // insecure, or if an error occurred.
never@3156: //
never@3156: static bool make_user_tmp_dir(const char* dirname) {
never@3156: 
never@3156:   // create the directory with 0755 permissions. note that the directory
never@3156:   // will be owned by euid::egid, which may not be the same as uid::gid.
never@3156:   //
never@3156:   if (mkdir(dirname, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) == OS_ERR) {
never@3156:     if (errno == EEXIST) {
never@3156:       // The directory already exists and was probably created by another
never@3156:       // JVM instance. However, this could also be the result of a
never@3156:       // deliberate symlink. Verify that the existing directory is safe.
never@3156:       //
never@3156:       if (!is_directory_secure(dirname)) {
never@3156:         // directory is not secure
never@3156:         if (PrintMiscellaneous && Verbose) {
never@3156:           warning("%s directory is insecure\n", dirname);
never@3156:         }
never@3156:         return false;
never@3156:       }
never@3156:     }
never@3156:     else {
never@3156:       // we encountered some other failure while attempting
never@3156:       // to create the directory
never@3156:       //
never@3156:       if (PrintMiscellaneous && Verbose) {
never@3156:         warning("could not create directory %s: %s\n",
never@3156:                 dirname, strerror(errno));
never@3156:       }
never@3156:       return false;
never@3156:     }
never@3156:   }
never@3156:   return true;
never@3156: }
never@3156: 
never@3156: // create the shared memory file resources
never@3156: //
never@3156: // This method creates the shared memory file with the given size
never@3156: // This method also creates the user specific temporary directory, if
never@3156: // it does not yet exist.
never@3156: //
never@3156: static int create_sharedmem_resources(const char* dirname, const char* filename, size_t size) {
never@3156: 
never@3156:   // make the user temporary directory
never@3156:   if (!make_user_tmp_dir(dirname)) {
never@3156:     // could not make/find the directory or the found directory
never@3156:     // was not secure
never@3156:     return -1;
never@3156:   }
never@3156: 
never@3156:   int result;
never@3156: 
never@3156:   RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_TRUNC, S_IREAD|S_IWRITE), result);
never@3156:   if (result == OS_ERR) {
never@3156:     if (PrintMiscellaneous && Verbose) {
never@3156:       warning("could not create file %s: %s\n", filename, strerror(errno));
never@3156:     }
never@3156:     return -1;
never@3156:   }
never@3156: 
never@3156:   // save the file descriptor
never@3156:   int fd = result;
never@3156: 
never@3156:   // set the file size
never@3156:   RESTARTABLE(::ftruncate(fd, (off_t)size), result);
never@3156:   if (result == OS_ERR) {
never@3156:     if (PrintMiscellaneous && Verbose) {
never@3156:       warning("could not set shared memory file size: %s\n", strerror(errno));
never@3156:     }
never@3156:     RESTARTABLE(::close(fd), result);
never@3156:     return -1;
never@3156:   }
never@3156: 
never@3156:   // Verify that we have enough disk space for this file.
never@3156:   // We'll get random SIGBUS crashes on memory accesses if
never@3156:   // we don't.
never@3156: 
never@3156:   for (size_t seekpos = 0; seekpos < size; seekpos += os::vm_page_size()) {
never@3156:     int zero_int = 0;
never@3156:     result = (int)os::seek_to_file_offset(fd, (jlong)(seekpos));
never@3156:     if (result == -1 ) break;
never@3156:     RESTARTABLE(::write(fd, &zero_int, 1), result);
never@3156:     if (result != 1) {
never@3156:       if (errno == ENOSPC) {
never@3156:         warning("Insufficient space for shared memory file:\n   %s\nTry using the -Djava.io.tmpdir= option to select an alternate temp location.\n", filename);
never@3156:       }
never@3156:       break;
never@3156:     }
never@3156:   }
never@3156: 
never@3156:   if (result != -1) {
never@3156:     return fd;
never@3156:   } else {
never@3156:     RESTARTABLE(::close(fd), result);
never@3156:     return -1;
never@3156:   }
never@3156: }
never@3156: 
never@3156: // open the shared memory file for the given user and vmid. returns
never@3156: // the file descriptor for the open file or -1 if the file could not
never@3156: // be opened.
never@3156: //
never@3156: static int open_sharedmem_file(const char* filename, int oflags, TRAPS) {
never@3156: 
never@3156:   // open the file
never@3156:   int result;
never@3156:   RESTARTABLE(::open(filename, oflags), result);
never@3156:   if (result == OS_ERR) {
never@3156:     if (errno == ENOENT) {
never@3156:       THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
never@3156:                   "Process not found");
never@3156:     }
never@3156:     else if (errno == EACCES) {
never@3156:       THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
never@3156:                   "Permission denied");
never@3156:     }
never@3156:     else {
never@3156:       THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
never@3156:     }
never@3156:   }
never@3156: 
never@3156:   return result;
never@3156: }
never@3156: 
never@3156: // create a named shared memory region. returns the address of the
never@3156: // memory region on success or NULL on failure. A return value of
never@3156: // NULL will ultimately disable the shared memory feature.
never@3156: //
never@3156: // On Solaris and Bsd, the name space for shared memory objects
never@3156: // is the file system name space.
never@3156: //
never@3156: // A monitoring application attaching to a JVM does not need to know
never@3156: // the file system name of the shared memory object. However, it may
never@3156: // be convenient for applications to discover the existence of newly
never@3156: // created and terminating JVMs by watching the file system name space
never@3156: // for files being created or removed.
never@3156: //
never@3156: static char* mmap_create_shared(size_t size) {
never@3156: 
never@3156:   int result;
never@3156:   int fd;
never@3156:   char* mapAddress;
never@3156: 
never@3156:   int vmid = os::current_process_id();
never@3156: 
never@3156:   char* user_name = get_user_name(geteuid());
never@3156: 
never@3156:   if (user_name == NULL)
never@3156:     return NULL;
never@3156: 
never@3156:   char* dirname = get_user_tmp_dir(user_name);
never@3156:   char* filename = get_sharedmem_filename(dirname, vmid);
never@3156: 
never@3156:   // cleanup any stale shared memory files
never@3156:   cleanup_sharedmem_resources(dirname);
never@3156: 
never@3156:   assert(((size > 0) && (size % os::vm_page_size() == 0)),
never@3156:          "unexpected PerfMemory region size");
never@3156: 
never@3156:   fd = create_sharedmem_resources(dirname, filename, size);
never@3156: 
zgu@3900:   FREE_C_HEAP_ARRAY(char, user_name, mtInternal);
zgu@3900:   FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
never@3156: 
never@3156:   if (fd == -1) {
zgu@3900:     FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156:     return NULL;
never@3156:   }
never@3156: 
never@3156:   mapAddress = (char*)::mmap((char*)0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
never@3156: 
never@3156:   // attempt to close the file - restart it if it was interrupted,
never@3156:   // but ignore other failures
never@3156:   RESTARTABLE(::close(fd), result);
never@3156:   assert(result != OS_ERR, "could not close file");
never@3156: 
never@3156:   if (mapAddress == MAP_FAILED) {
never@3156:     if (PrintMiscellaneous && Verbose) {
never@3156:       warning("mmap failed -  %s\n", strerror(errno));
never@3156:     }
never@3156:     remove_file(filename);
zgu@3900:     FREE_C_HEAP_ARRAY(char, filename, mtInternal);
never@3156:     return NULL;
never@3156:   }
never@3156: 
never@3156:   // save the file name for use in delete_shared_memory()
never@3156:   backing_store_file_name = filename;
never@3156: 
never@3156:   // clear the shared memory region
never@3156:   (void)::memset((void*) mapAddress, 0, size);
never@3156: 
never@3156:   return mapAddress;
never@3156: }
never@3156: 
never@3156: // release a named shared memory region
never@3156: //
never@3156: static void unmap_shared(char* addr, size_t bytes) {
never@3156:   os::release_memory(addr, bytes);
never@3156: }
never@3156: 
never@3156: // create the PerfData memory region in shared memory.
never@3156: //
never@3156: static char* create_shared_memory(size_t size) {
never@3156: 
never@3156:   // create the shared memory region.
never@3156:   return mmap_create_shared(size);
never@3156: }
never@3156: 
never@3156: // delete the shared PerfData memory region
never@3156: //
never@3156: static void delete_shared_memory(char* addr, size_t size) {
never@3156: 
never@3156:   // cleanup the persistent shared memory resources. since DestroyJavaVM does
never@3156:   // not support unloading of the JVM, unmapping of the memory resource is
never@3156:   // not performed. The memory will be reclaimed by the OS upon termination of
never@3156:   // the process. The backing store file is deleted from the file system.
never@3156: 
never@3156:   assert(!PerfDisableSharedMem, "shouldn't be here");
never@3156: 
never@3156:   if (backing_store_file_name != NULL) {
never@3156:     remove_file(backing_store_file_name);
never@3156:     // Don't.. Free heap memory could deadlock os::abort() if it is called
never@3156:     // from signal handler. OS will reclaim the heap memory.
never@3156:     // FREE_C_HEAP_ARRAY(char, backing_store_file_name);
never@3156:     backing_store_file_name = NULL;
never@3156:   }
never@3156: }
never@3156: 
never@3156: // return the size of the file for the given file descriptor
never@3156: // or 0 if it is not a valid size for a shared memory file
never@3156: //
never@3156: static size_t sharedmem_filesize(int fd, TRAPS) {
never@3156: 
never@3156:   struct stat statbuf;
never@3156:   int result;
never@3156: 
never@3156:   RESTARTABLE(::fstat(fd, &statbuf), result);
never@3156:   if (result == OS_ERR) {
never@3156:     if (PrintMiscellaneous && Verbose) {
never@3156:       warning("fstat failed: %s\n", strerror(errno));
never@3156:     }
never@3156:     THROW_MSG_0(vmSymbols::java_io_IOException(),
never@3156:                 "Could not determine PerfMemory size");
never@3156:   }
never@3156: 
never@3156:   if ((statbuf.st_size == 0) ||
never@3156:      ((size_t)statbuf.st_size % os::vm_page_size() != 0)) {
never@3156:     THROW_MSG_0(vmSymbols::java_lang_Exception(),
never@3156:                 "Invalid PerfMemory size");
never@3156:   }
never@3156: 
never@3156:   return (size_t)statbuf.st_size;
never@3156: }
never@3156: 
never@3156: // attach to a named shared memory region.
never@3156: //
never@3156: static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemoryMode mode, char** addr, size_t* sizep, TRAPS) {
never@3156: 
never@3156:   char* mapAddress;
never@3156:   int result;
never@3156:   int fd;
never@3156:   size_t size;
never@3156:   const char* luser = NULL;
never@3156: 
never@3156:   int mmap_prot;
never@3156:   int file_flags;
never@3156: 
never@3156:   ResourceMark rm;
never@3156: 
never@3156:   // map the high level access mode to the appropriate permission
never@3156:   // constructs for the file and the shared memory mapping.
never@3156:   if (mode == PerfMemory::PERF_MODE_RO) {
never@3156:     mmap_prot = PROT_READ;
never@3156:     file_flags = O_RDONLY;
never@3156:   }
never@3156:   else if (mode == PerfMemory::PERF_MODE_RW) {
never@3156: #ifdef LATER
never@3156:     mmap_prot = PROT_READ | PROT_WRITE;
never@3156:     file_flags = O_RDWR;
never@3156: #else
never@3156:     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
never@3156:               "Unsupported access mode");
never@3156: #endif
never@3156:   }
never@3156:   else {
never@3156:     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
never@3156:               "Illegal access mode");
never@3156:   }
never@3156: 
never@3156:   if (user == NULL || strlen(user) == 0) {
never@3156:     luser = get_user_name(vmid, CHECK);
never@3156:   }
never@3156:   else {
never@3156:     luser = user;
never@3156:   }
never@3156: 
never@3156:   if (luser == NULL) {
never@3156:     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
never@3156:               "Could not map vmid to user Name");
never@3156:   }
never@3156: 
never@3156:   char* dirname = get_user_tmp_dir(luser);
never@3156: 
never@3156:   // since we don't follow symbolic links when creating the backing
never@3156:   // store file, we don't follow them when attaching either.
never@3156:   //
never@3156:   if (!is_directory_secure(dirname)) {
zgu@3900:     FREE_C_HEAP_ARRAY(char, dirname, mtInternal);
never@3156:     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
never@3156:               "Process not found");
never@3156:   }
never@3156: 
never@3156:   char* filename = get_sharedmem_filename(dirname, vmid);
never@3156: 
never@3156:   // copy heap memory to resource memory. the open_sharedmem_file
never@3156:   // method below need to use the filename, but could throw an
never@3156:   // exception. using a resource array prevents the leak that
never@3156:   // would otherwise occur.
never@3156:   char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
never@3156:   strcpy(rfilename, filename);
never@3156: 
never@3156:   // 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);
never@3156: 
never@3156:   // open the shared memory file for the give vmid
never@3156:   fd = open_sharedmem_file(rfilename, file_flags, CHECK);
never@3156:   assert(fd != OS_ERR, "unexpected value");
never@3156: 
never@3156:   if (*sizep == 0) {
never@3156:     size = sharedmem_filesize(fd, CHECK);
never@3156:     assert(size != 0, "unexpected size");
never@3156:   }
never@3156: 
never@3156:   mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0);
never@3156: 
never@3156:   // attempt to close the file - restart if it gets interrupted,
never@3156:   // but ignore other failures
never@3156:   RESTARTABLE(::close(fd), result);
never@3156:   assert(result != OS_ERR, "could not close file");
never@3156: 
never@3156:   if (mapAddress == MAP_FAILED) {
never@3156:     if (PrintMiscellaneous && Verbose) {
never@3156:       warning("mmap failed: %s\n", strerror(errno));
never@3156:     }
never@3156:     THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
never@3156:               "Could not map PerfMemory");
never@3156:   }
never@3156: 
never@3156:   *addr = mapAddress;
never@3156:   *sizep = size;
never@3156: 
never@3156:   if (PerfTraceMemOps) {
never@3156:     tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at "
never@3156:                INTPTR_FORMAT "\n", size, vmid, (void*)mapAddress);
never@3156:   }
never@3156: }
never@3156: 
never@3156: 
never@3156: 
never@3156: 
never@3156: // create the PerfData memory region
never@3156: //
never@3156: // This method creates the memory region used to store performance
never@3156: // data for the JVM. The memory may be created in standard or
never@3156: // shared memory.
never@3156: //
never@3156: void PerfMemory::create_memory_region(size_t size) {
never@3156: 
never@3156:   if (PerfDisableSharedMem) {
never@3156:     // do not share the memory for the performance data.
never@3156:     _start = create_standard_memory(size);
never@3156:   }
never@3156:   else {
never@3156:     _start = create_shared_memory(size);
never@3156:     if (_start == NULL) {
never@3156: 
never@3156:       // creation of the shared memory region failed, attempt
never@3156:       // to create a contiguous, non-shared memory region instead.
never@3156:       //
never@3156:       if (PrintMiscellaneous && Verbose) {
never@3156:         warning("Reverting to non-shared PerfMemory region.\n");
never@3156:       }
never@3156:       PerfDisableSharedMem = true;
never@3156:       _start = create_standard_memory(size);
never@3156:     }
never@3156:   }
never@3156: 
never@3156:   if (_start != NULL) _capacity = size;
never@3156: 
never@3156: }
never@3156: 
never@3156: // delete the PerfData memory region
never@3156: //
never@3156: // This method deletes the memory region used to store performance
never@3156: // data for the JVM. The memory region indicated by the <address, size>
never@3156: // tuple will be inaccessible after a call to this method.
never@3156: //
never@3156: void PerfMemory::delete_memory_region() {
never@3156: 
never@3156:   assert((start() != NULL && capacity() > 0), "verify proper state");
never@3156: 
never@3156:   // If user specifies PerfDataSaveFile, it will save the performance data
never@3156:   // to the specified file name no matter whether PerfDataSaveToFile is specified
never@3156:   // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
never@3156:   // -XX:+PerfDataSaveToFile.
never@3156:   if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
never@3156:     save_memory_to_file(start(), capacity());
never@3156:   }
never@3156: 
never@3156:   if (PerfDisableSharedMem) {
never@3156:     delete_standard_memory(start(), capacity());
never@3156:   }
never@3156:   else {
never@3156:     delete_shared_memory(start(), capacity());
never@3156:   }
never@3156: }
never@3156: 
never@3156: // attach to the PerfData memory region for another JVM
never@3156: //
never@3156: // This method returns an <address, size> tuple that points to
never@3156: // a memory buffer that is kept reasonably synchronized with
never@3156: // the PerfData memory region for the indicated JVM. This
never@3156: // buffer may be kept in synchronization via shared memory
never@3156: // or some other mechanism that keeps the buffer updated.
never@3156: //
never@3156: // If the JVM chooses not to support the attachability feature,
never@3156: // this method should throw an UnsupportedOperation exception.
never@3156: //
never@3156: // This implementation utilizes named shared memory to map
never@3156: // the indicated process's PerfData memory region into this JVMs
never@3156: // address space.
never@3156: //
never@3156: void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, char** addrp, size_t* sizep, TRAPS) {
never@3156: 
never@3156:   if (vmid == 0 || vmid == os::current_process_id()) {
never@3156:      *addrp = start();
never@3156:      *sizep = capacity();
never@3156:      return;
never@3156:   }
never@3156: 
never@3156:   mmap_attach_shared(user, vmid, mode, addrp, sizep, CHECK);
never@3156: }
never@3156: 
never@3156: // detach from the PerfData memory region of another JVM
never@3156: //
never@3156: // This method detaches the PerfData memory region of another
never@3156: // JVM, specified as an <address, size> tuple of a buffer
never@3156: // in this process's address space. This method may perform
never@3156: // arbitrary actions to accomplish the detachment. The memory
never@3156: // region specified by <address, size> will be inaccessible after
never@3156: // a call to this method.
never@3156: //
never@3156: // If the JVM chooses not to support the attachability feature,
never@3156: // this method should throw an UnsupportedOperation exception.
never@3156: //
never@3156: // This implementation utilizes named shared memory to detach
never@3156: // the indicated process's PerfData memory region from this
never@3156: // process's address space.
never@3156: //
never@3156: void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
never@3156: 
never@3156:   assert(addr != 0, "address sanity check");
never@3156:   assert(bytes > 0, "capacity sanity check");
never@3156: 
never@3156:   if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
never@3156:     // prevent accidental detachment of this process's PerfMemory region
never@3156:     return;
never@3156:   }
never@3156: 
never@3156:   unmap_shared(addr, bytes);
never@3156: }
never@3156: 
never@3156: char* PerfMemory::backing_store_filename() {
never@3156:   return backing_store_file_name;
never@3156: }