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0
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1 /*
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2 * Copyright 2001-2006 Sun Microsystems, Inc. All Rights Reserved.
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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4 *
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5 * This code is free software; you can redistribute it and/or modify it
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6 * under the terms of the GNU General Public License version 2 only, as
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7 * published by the Free Software Foundation.
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8 *
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9 * This code is distributed in the hope that it will be useful, but WITHOUT
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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12 * version 2 for more details (a copy is included in the LICENSE file that
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13 * accompanied this code).
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14 *
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15 * You should have received a copy of the GNU General Public License version
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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18 *
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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25 # include "incls/_precompiled.incl"
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26 # include "incls/_perfMemory_linux.cpp.incl"
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27
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28 // put OS-includes here
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29 # include <sys/types.h>
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30 # include <sys/mman.h>
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31 # include <errno.h>
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32 # include <stdio.h>
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33 # include <unistd.h>
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34 # include <sys/stat.h>
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35 # include <signal.h>
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36 # include <pwd.h>
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37
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38 static char* backing_store_file_name = NULL; // name of the backing store
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39 // file, if successfully created.
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40
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41 // Standard Memory Implementation Details
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42
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43 // create the PerfData memory region in standard memory.
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44 //
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45 static char* create_standard_memory(size_t size) {
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46
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47 // allocate an aligned chuck of memory
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48 char* mapAddress = os::reserve_memory(size);
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49
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50 if (mapAddress == NULL) {
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51 return NULL;
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52 }
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53
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54 // commit memory
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55 if (!os::commit_memory(mapAddress, size)) {
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56 if (PrintMiscellaneous && Verbose) {
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57 warning("Could not commit PerfData memory\n");
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58 }
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59 os::release_memory(mapAddress, size);
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60 return NULL;
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61 }
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62
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63 return mapAddress;
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64 }
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65
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66 // delete the PerfData memory region
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67 //
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68 static void delete_standard_memory(char* addr, size_t size) {
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69
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70 // there are no persistent external resources to cleanup for standard
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71 // memory. since DestroyJavaVM does not support unloading of the JVM,
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72 // cleanup of the memory resource is not performed. The memory will be
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73 // reclaimed by the OS upon termination of the process.
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74 //
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75 return;
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76 }
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77
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78 // save the specified memory region to the given file
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79 //
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80 // Note: this function might be called from signal handler (by os::abort()),
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81 // don't allocate heap memory.
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82 //
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83 static void save_memory_to_file(char* addr, size_t size) {
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84
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85 const char* destfile = PerfMemory::get_perfdata_file_path();
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86 assert(destfile[0] != '\0', "invalid PerfData file path");
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87
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88 int result;
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89
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90 RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE),
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91 result);;
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92 if (result == OS_ERR) {
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93 if (PrintMiscellaneous && Verbose) {
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94 warning("Could not create Perfdata save file: %s: %s\n",
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95 destfile, strerror(errno));
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96 }
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97 } else {
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98 int fd = result;
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99
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100 for (size_t remaining = size; remaining > 0;) {
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101
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102 RESTARTABLE(::write(fd, addr, remaining), result);
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103 if (result == OS_ERR) {
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104 if (PrintMiscellaneous && Verbose) {
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105 warning("Could not write Perfdata save file: %s: %s\n",
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106 destfile, strerror(errno));
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107 }
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108 break;
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109 }
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110
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111 remaining -= (size_t)result;
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112 addr += result;
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113 }
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114
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115 RESTARTABLE(::close(fd), result);
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116 if (PrintMiscellaneous && Verbose) {
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117 if (result == OS_ERR) {
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118 warning("Could not close %s: %s\n", destfile, strerror(errno));
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119 }
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120 }
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121 }
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122 FREE_C_HEAP_ARRAY(char, destfile);
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123 }
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124
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125
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126 // Shared Memory Implementation Details
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127
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128 // Note: the solaris and linux shared memory implementation uses the mmap
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129 // interface with a backing store file to implement named shared memory.
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130 // Using the file system as the name space for shared memory allows a
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131 // common name space to be supported across a variety of platforms. It
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132 // also provides a name space that Java applications can deal with through
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133 // simple file apis.
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134 //
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135 // The solaris and linux implementations store the backing store file in
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136 // a user specific temporary directory located in the /tmp file system,
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137 // which is always a local file system and is sometimes a RAM based file
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138 // system.
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139
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140 // return the user specific temporary directory name.
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141 //
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142 // the caller is expected to free the allocated memory.
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143 //
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144 static char* get_user_tmp_dir(const char* user) {
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145
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146 const char* tmpdir = os::get_temp_directory();
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147 const char* perfdir = PERFDATA_NAME;
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148 size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 2;
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149 char* dirname = NEW_C_HEAP_ARRAY(char, nbytes);
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150
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151 // construct the path name to user specific tmp directory
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152 snprintf(dirname, nbytes, "%s%s_%s", tmpdir, perfdir, user);
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153
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154 return dirname;
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155 }
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156
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157 // convert the given file name into a process id. if the file
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158 // does not meet the file naming constraints, return 0.
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159 //
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160 static pid_t filename_to_pid(const char* filename) {
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161
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162 // a filename that doesn't begin with a digit is not a
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163 // candidate for conversion.
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164 //
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165 if (!isdigit(*filename)) {
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166 return 0;
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167 }
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168
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169 // check if file name can be converted to an integer without
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170 // any leftover characters.
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171 //
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172 char* remainder = NULL;
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173 errno = 0;
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174 pid_t pid = (pid_t)strtol(filename, &remainder, 10);
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175
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176 if (errno != 0) {
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177 return 0;
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178 }
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179
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180 // check for left over characters. If any, then the filename is
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181 // not a candidate for conversion.
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182 //
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183 if (remainder != NULL && *remainder != '\0') {
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184 return 0;
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185 }
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186
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187 // successful conversion, return the pid
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188 return pid;
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189 }
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190
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191
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192 // check if the given path is considered a secure directory for
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193 // the backing store files. Returns true if the directory exists
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194 // and is considered a secure location. Returns false if the path
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195 // is a symbolic link or if an error occurred.
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0
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196 //
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197 static bool is_directory_secure(const char* path) {
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198 struct stat statbuf;
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199 int result = 0;
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200
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201 RESTARTABLE(::lstat(path, &statbuf), result);
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202 if (result == OS_ERR) {
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203 return false;
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204 }
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205
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206 // the path exists, now check it's mode
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207 if (S_ISLNK(statbuf.st_mode) || !S_ISDIR(statbuf.st_mode)) {
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208 // the path represents a link or some non-directory file type,
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209 // which is not what we expected. declare it insecure.
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210 //
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211 return false;
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212 }
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213 else {
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214 // we have an existing directory, check if the permissions are safe.
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215 //
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216 if ((statbuf.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
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217 // the directory is open for writing and could be subjected
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218 // to a symlnk attack. declare it insecure.
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219 //
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220 return false;
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221 }
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222 }
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223 return true;
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224 }
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225
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226
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227 // return the user name for the given user id
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228 //
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229 // the caller is expected to free the allocated memory.
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230 //
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231 static char* get_user_name(uid_t uid) {
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232
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233 struct passwd pwent;
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234
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235 // determine the max pwbuf size from sysconf, and hardcode
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236 // a default if this not available through sysconf.
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237 //
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238 long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
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239 if (bufsize == -1)
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240 bufsize = 1024;
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241
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242 char* pwbuf = NEW_C_HEAP_ARRAY(char, bufsize);
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243
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244 // POSIX interface to getpwuid_r is used on LINUX
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245 struct passwd* p;
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246 int result = getpwuid_r(uid, &pwent, pwbuf, (size_t)bufsize, &p);
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247
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248 if (result != 0 || p == NULL || p->pw_name == NULL || *(p->pw_name) == '\0') {
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249 if (PrintMiscellaneous && Verbose) {
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250 if (result != 0) {
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251 warning("Could not retrieve passwd entry: %s\n",
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252 strerror(result));
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253 }
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254 else if (p == NULL) {
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255 // this check is added to protect against an observed problem
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256 // with getpwuid_r() on RedHat 9 where getpwuid_r returns 0,
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257 // indicating success, but has p == NULL. This was observed when
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258 // inserting a file descriptor exhaustion fault prior to the call
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259 // getpwuid_r() call. In this case, error is set to the appropriate
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260 // error condition, but this is undocumented behavior. This check
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261 // is safe under any condition, but the use of errno in the output
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262 // message may result in an erroneous message.
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263 // Bug Id 89052 was opened with RedHat.
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264 //
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265 warning("Could not retrieve passwd entry: %s\n",
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266 strerror(errno));
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267 }
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268 else {
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269 warning("Could not determine user name: %s\n",
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270 p->pw_name == NULL ? "pw_name = NULL" :
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271 "pw_name zero length");
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272 }
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273 }
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274 FREE_C_HEAP_ARRAY(char, pwbuf);
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275 return NULL;
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276 }
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277
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278 char* user_name = NEW_C_HEAP_ARRAY(char, strlen(p->pw_name) + 1);
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279 strcpy(user_name, p->pw_name);
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280
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281 FREE_C_HEAP_ARRAY(char, pwbuf);
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282 return user_name;
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283 }
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284
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285 // return the name of the user that owns the process identified by vmid.
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286 //
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287 // This method uses a slow directory search algorithm to find the backing
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288 // store file for the specified vmid and returns the user name, as determined
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289 // by the user name suffix of the hsperfdata_<username> directory name.
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290 //
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291 // the caller is expected to free the allocated memory.
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292 //
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293 static char* get_user_name_slow(int vmid, TRAPS) {
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294
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295 // short circuit the directory search if the process doesn't even exist.
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296 if (kill(vmid, 0) == OS_ERR) {
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297 if (errno == ESRCH) {
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298 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
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299 "Process not found");
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300 }
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301 else /* EPERM */ {
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302 THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
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303 }
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304 }
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305
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306 // directory search
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307 char* oldest_user = NULL;
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308 time_t oldest_ctime = 0;
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309
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310 const char* tmpdirname = os::get_temp_directory();
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311
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312 DIR* tmpdirp = os::opendir(tmpdirname);
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313
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314 if (tmpdirp == NULL) {
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315 return NULL;
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316 }
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317
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318 // for each entry in the directory that matches the pattern hsperfdata_*,
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319 // open the directory and check if the file for the given vmid exists.
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320 // The file with the expected name and the latest creation date is used
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321 // to determine the user name for the process id.
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322 //
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323 struct dirent* dentry;
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324 char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname));
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325 errno = 0;
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326 while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) {
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327
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328 // check if the directory entry is a hsperfdata file
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329 if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
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330 continue;
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331 }
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332
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333 char* usrdir_name = NEW_C_HEAP_ARRAY(char,
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334 strlen(tmpdirname) + strlen(dentry->d_name) + 1);
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335 strcpy(usrdir_name, tmpdirname);
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336 strcat(usrdir_name, dentry->d_name);
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337
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338 DIR* subdirp = os::opendir(usrdir_name);
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339
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340 if (subdirp == NULL) {
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341 FREE_C_HEAP_ARRAY(char, usrdir_name);
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342 continue;
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343 }
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344
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345 // Since we don't create the backing store files in directories
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346 // pointed to by symbolic links, we also don't follow them when
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347 // looking for the files. We check for a symbolic link after the
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348 // call to opendir in order to eliminate a small window where the
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349 // symlink can be exploited.
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350 //
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351 if (!is_directory_secure(usrdir_name)) {
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352 FREE_C_HEAP_ARRAY(char, usrdir_name);
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353 os::closedir(subdirp);
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354 continue;
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355 }
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356
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357 struct dirent* udentry;
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358 char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name));
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359 errno = 0;
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360 while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
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361
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362 if (filename_to_pid(udentry->d_name) == vmid) {
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363 struct stat statbuf;
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364 int result;
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365
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366 char* filename = NEW_C_HEAP_ARRAY(char,
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367 strlen(usrdir_name) + strlen(udentry->d_name) + 2);
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368
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369 strcpy(filename, usrdir_name);
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370 strcat(filename, "/");
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371 strcat(filename, udentry->d_name);
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372
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373 // don't follow symbolic links for the file
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374 RESTARTABLE(::lstat(filename, &statbuf), result);
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375 if (result == OS_ERR) {
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376 FREE_C_HEAP_ARRAY(char, filename);
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377 continue;
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378 }
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379
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380 // skip over files that are not regular files.
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381 if (!S_ISREG(statbuf.st_mode)) {
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382 FREE_C_HEAP_ARRAY(char, filename);
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383 continue;
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384 }
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385
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386 // compare and save filename with latest creation time
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387 if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) {
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388
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389 if (statbuf.st_ctime > oldest_ctime) {
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390 char* user = strchr(dentry->d_name, '_') + 1;
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391
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392 if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user);
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393 oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1);
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394
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395 strcpy(oldest_user, user);
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396 oldest_ctime = statbuf.st_ctime;
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397 }
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398 }
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399
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400 FREE_C_HEAP_ARRAY(char, filename);
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401 }
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402 }
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403 os::closedir(subdirp);
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404 FREE_C_HEAP_ARRAY(char, udbuf);
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405 FREE_C_HEAP_ARRAY(char, usrdir_name);
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406 }
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407 os::closedir(tmpdirp);
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408 FREE_C_HEAP_ARRAY(char, tdbuf);
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409
|
|
|
410 return(oldest_user);
|
|
|
411 }
|
|
|
412
|
|
|
413 // return the name of the user that owns the JVM indicated by the given vmid.
|
|
|
414 //
|
|
|
415 static char* get_user_name(int vmid, TRAPS) {
|
|
|
416 return get_user_name_slow(vmid, CHECK_NULL);
|
|
|
417 }
|
|
|
418
|
|
|
419 // return the file name of the backing store file for the named
|
|
|
420 // shared memory region for the given user name and vmid.
|
|
|
421 //
|
|
|
422 // the caller is expected to free the allocated memory.
|
|
|
423 //
|
|
|
424 static char* get_sharedmem_filename(const char* dirname, int vmid) {
|
|
|
425
|
|
|
426 // add 2 for the file separator and a null terminator.
|
|
|
427 size_t nbytes = strlen(dirname) + UINT_CHARS + 2;
|
|
|
428
|
|
|
429 char* name = NEW_C_HEAP_ARRAY(char, nbytes);
|
|
|
430 snprintf(name, nbytes, "%s/%d", dirname, vmid);
|
|
|
431
|
|
|
432 return name;
|
|
|
433 }
|
|
|
434
|
|
|
435
|
|
|
436 // remove file
|
|
|
437 //
|
|
|
438 // this method removes the file specified by the given path
|
|
|
439 //
|
|
|
440 static void remove_file(const char* path) {
|
|
|
441
|
|
|
442 int result;
|
|
|
443
|
|
|
444 // if the file is a directory, the following unlink will fail. since
|
|
|
445 // we don't expect to find directories in the user temp directory, we
|
|
|
446 // won't try to handle this situation. even if accidentially or
|
|
|
447 // maliciously planted, the directory's presence won't hurt anything.
|
|
|
448 //
|
|
|
449 RESTARTABLE(::unlink(path), result);
|
|
|
450 if (PrintMiscellaneous && Verbose && result == OS_ERR) {
|
|
|
451 if (errno != ENOENT) {
|
|
|
452 warning("Could not unlink shared memory backing"
|
|
|
453 " store file %s : %s\n", path, strerror(errno));
|
|
|
454 }
|
|
|
455 }
|
|
|
456 }
|
|
|
457
|
|
|
458
|
|
|
459 // remove file
|
|
|
460 //
|
|
|
461 // this method removes the file with the given file name in the
|
|
|
462 // named directory.
|
|
|
463 //
|
|
|
464 static void remove_file(const char* dirname, const char* filename) {
|
|
|
465
|
|
|
466 size_t nbytes = strlen(dirname) + strlen(filename) + 2;
|
|
|
467 char* path = NEW_C_HEAP_ARRAY(char, nbytes);
|
|
|
468
|
|
|
469 strcpy(path, dirname);
|
|
|
470 strcat(path, "/");
|
|
|
471 strcat(path, filename);
|
|
|
472
|
|
|
473 remove_file(path);
|
|
|
474
|
|
|
475 FREE_C_HEAP_ARRAY(char, path);
|
|
|
476 }
|
|
|
477
|
|
|
478
|
|
|
479 // cleanup stale shared memory resources
|
|
|
480 //
|
|
|
481 // This method attempts to remove all stale shared memory files in
|
|
|
482 // the named user temporary directory. It scans the named directory
|
|
|
483 // for files matching the pattern ^$[0-9]*$. For each file found, the
|
|
|
484 // process id is extracted from the file name and a test is run to
|
|
|
485 // determine if the process is alive. If the process is not alive,
|
|
|
486 // any stale file resources are removed.
|
|
|
487 //
|
|
|
488 static void cleanup_sharedmem_resources(const char* dirname) {
|
|
|
489
|
|
|
490 // open the user temp directory
|
|
|
491 DIR* dirp = os::opendir(dirname);
|
|
|
492
|
|
|
493 if (dirp == NULL) {
|
|
|
494 // directory doesn't exist, so there is nothing to cleanup
|
|
|
495 return;
|
|
|
496 }
|
|
|
497
|
|
|
498 if (!is_directory_secure(dirname)) {
|
|
|
499 // the directory is not a secure directory
|
|
|
500 return;
|
|
|
501 }
|
|
|
502
|
|
|
503 // for each entry in the directory that matches the expected file
|
|
|
504 // name pattern, determine if the file resources are stale and if
|
|
|
505 // so, remove the file resources. Note, instrumented HotSpot processes
|
|
|
506 // for this user may start and/or terminate during this search and
|
|
|
507 // remove or create new files in this directory. The behavior of this
|
|
|
508 // loop under these conditions is dependent upon the implementation of
|
|
|
509 // opendir/readdir.
|
|
|
510 //
|
|
|
511 struct dirent* entry;
|
|
|
512 char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname));
|
|
|
513 errno = 0;
|
|
|
514 while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) {
|
|
|
515
|
|
|
516 pid_t pid = filename_to_pid(entry->d_name);
|
|
|
517
|
|
|
518 if (pid == 0) {
|
|
|
519
|
|
|
520 if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
|
|
|
521
|
|
|
522 // attempt to remove all unexpected files, except "." and ".."
|
|
|
523 remove_file(dirname, entry->d_name);
|
|
|
524 }
|
|
|
525
|
|
|
526 errno = 0;
|
|
|
527 continue;
|
|
|
528 }
|
|
|
529
|
|
|
530 // we now have a file name that converts to a valid integer
|
|
|
531 // that could represent a process id . if this process id
|
|
|
532 // matches the current process id or the process is not running,
|
|
|
533 // then remove the stale file resources.
|
|
|
534 //
|
|
|
535 // process liveness is detected by sending signal number 0 to
|
|
|
536 // the process id (see kill(2)). if kill determines that the
|
|
|
537 // process does not exist, then the file resources are removed.
|
|
|
538 // if kill determines that that we don't have permission to
|
|
|
539 // signal the process, then the file resources are assumed to
|
|
|
540 // be stale and are removed because the resources for such a
|
|
|
541 // process should be in a different user specific directory.
|
|
|
542 //
|
|
|
543 if ((pid == os::current_process_id()) ||
|
|
|
544 (kill(pid, 0) == OS_ERR && (errno == ESRCH || errno == EPERM))) {
|
|
|
545
|
|
|
546 remove_file(dirname, entry->d_name);
|
|
|
547 }
|
|
|
548 errno = 0;
|
|
|
549 }
|
|
|
550 os::closedir(dirp);
|
|
|
551 FREE_C_HEAP_ARRAY(char, dbuf);
|
|
|
552 }
|
|
|
553
|
|
|
554 // make the user specific temporary directory. Returns true if
|
|
|
555 // the directory exists and is secure upon return. Returns false
|
|
|
556 // if the directory exists but is either a symlink, is otherwise
|
|
|
557 // insecure, or if an error occurred.
|
|
|
558 //
|
|
|
559 static bool make_user_tmp_dir(const char* dirname) {
|
|
|
560
|
|
|
561 // create the directory with 0755 permissions. note that the directory
|
|
|
562 // will be owned by euid::egid, which may not be the same as uid::gid.
|
|
|
563 //
|
|
|
564 if (mkdir(dirname, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) == OS_ERR) {
|
|
|
565 if (errno == EEXIST) {
|
|
|
566 // The directory already exists and was probably created by another
|
|
|
567 // JVM instance. However, this could also be the result of a
|
|
|
568 // deliberate symlink. Verify that the existing directory is safe.
|
|
|
569 //
|
|
|
570 if (!is_directory_secure(dirname)) {
|
|
|
571 // directory is not secure
|
|
|
572 if (PrintMiscellaneous && Verbose) {
|
|
|
573 warning("%s directory is insecure\n", dirname);
|
|
|
574 }
|
|
|
575 return false;
|
|
|
576 }
|
|
|
577 }
|
|
|
578 else {
|
|
|
579 // we encountered some other failure while attempting
|
|
|
580 // to create the directory
|
|
|
581 //
|
|
|
582 if (PrintMiscellaneous && Verbose) {
|
|
|
583 warning("could not create directory %s: %s\n",
|
|
|
584 dirname, strerror(errno));
|
|
|
585 }
|
|
|
586 return false;
|
|
|
587 }
|
|
|
588 }
|
|
|
589 return true;
|
|
|
590 }
|
|
|
591
|
|
|
592 // create the shared memory file resources
|
|
|
593 //
|
|
|
594 // This method creates the shared memory file with the given size
|
|
|
595 // This method also creates the user specific temporary directory, if
|
|
|
596 // it does not yet exist.
|
|
|
597 //
|
|
|
598 static int create_sharedmem_resources(const char* dirname, const char* filename, size_t size) {
|
|
|
599
|
|
|
600 // make the user temporary directory
|
|
|
601 if (!make_user_tmp_dir(dirname)) {
|
|
|
602 // could not make/find the directory or the found directory
|
|
|
603 // was not secure
|
|
|
604 return -1;
|
|
|
605 }
|
|
|
606
|
|
|
607 int result;
|
|
|
608
|
|
|
609 RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_TRUNC, S_IREAD|S_IWRITE), result);
|
|
|
610 if (result == OS_ERR) {
|
|
|
611 if (PrintMiscellaneous && Verbose) {
|
|
|
612 warning("could not create file %s: %s\n", filename, strerror(errno));
|
|
|
613 }
|
|
|
614 return -1;
|
|
|
615 }
|
|
|
616
|
|
|
617 // save the file descriptor
|
|
|
618 int fd = result;
|
|
|
619
|
|
|
620 // set the file size
|
|
|
621 RESTARTABLE(::ftruncate(fd, (off_t)size), result);
|
|
|
622 if (result == OS_ERR) {
|
|
|
623 if (PrintMiscellaneous && Verbose) {
|
|
|
624 warning("could not set shared memory file size: %s\n", strerror(errno));
|
|
|
625 }
|
|
|
626 RESTARTABLE(::close(fd), result);
|
|
|
627 return -1;
|
|
|
628 }
|
|
|
629
|
|
|
630 return fd;
|
|
|
631 }
|
|
|
632
|
|
|
633 // open the shared memory file for the given user and vmid. returns
|
|
|
634 // the file descriptor for the open file or -1 if the file could not
|
|
|
635 // be opened.
|
|
|
636 //
|
|
|
637 static int open_sharedmem_file(const char* filename, int oflags, TRAPS) {
|
|
|
638
|
|
|
639 // open the file
|
|
|
640 int result;
|
|
|
641 RESTARTABLE(::open(filename, oflags), result);
|
|
|
642 if (result == OS_ERR) {
|
|
|
643 if (errno == ENOENT) {
|
|
|
644 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
|
|
|
645 "Process not found");
|
|
|
646 }
|
|
|
647 else if (errno == EACCES) {
|
|
|
648 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
|
|
|
649 "Permission denied");
|
|
|
650 }
|
|
|
651 else {
|
|
|
652 THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
|
|
|
653 }
|
|
|
654 }
|
|
|
655
|
|
|
656 return result;
|
|
|
657 }
|
|
|
658
|
|
|
659 // create a named shared memory region. returns the address of the
|
|
|
660 // memory region on success or NULL on failure. A return value of
|
|
|
661 // NULL will ultimately disable the shared memory feature.
|
|
|
662 //
|
|
|
663 // On Solaris and Linux, the name space for shared memory objects
|
|
|
664 // is the file system name space.
|
|
|
665 //
|
|
|
666 // A monitoring application attaching to a JVM does not need to know
|
|
|
667 // the file system name of the shared memory object. However, it may
|
|
|
668 // be convenient for applications to discover the existence of newly
|
|
|
669 // created and terminating JVMs by watching the file system name space
|
|
|
670 // for files being created or removed.
|
|
|
671 //
|
|
|
672 static char* mmap_create_shared(size_t size) {
|
|
|
673
|
|
|
674 int result;
|
|
|
675 int fd;
|
|
|
676 char* mapAddress;
|
|
|
677
|
|
|
678 int vmid = os::current_process_id();
|
|
|
679
|
|
|
680 char* user_name = get_user_name(geteuid());
|
|
|
681
|
|
|
682 if (user_name == NULL)
|
|
|
683 return NULL;
|
|
|
684
|
|
|
685 char* dirname = get_user_tmp_dir(user_name);
|
|
|
686 char* filename = get_sharedmem_filename(dirname, vmid);
|
|
|
687
|
|
|
688 // cleanup any stale shared memory files
|
|
|
689 cleanup_sharedmem_resources(dirname);
|
|
|
690
|
|
|
691 assert(((size > 0) && (size % os::vm_page_size() == 0)),
|
|
|
692 "unexpected PerfMemory region size");
|
|
|
693
|
|
|
694 fd = create_sharedmem_resources(dirname, filename, size);
|
|
|
695
|
|
|
696 FREE_C_HEAP_ARRAY(char, user_name);
|
|
|
697 FREE_C_HEAP_ARRAY(char, dirname);
|
|
|
698
|
|
|
699 if (fd == -1) {
|
|
|
700 FREE_C_HEAP_ARRAY(char, filename);
|
|
|
701 return NULL;
|
|
|
702 }
|
|
|
703
|
|
|
704 mapAddress = (char*)::mmap((char*)0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
|
|
|
705
|
|
|
706 // attempt to close the file - restart it if it was interrupted,
|
|
|
707 // but ignore other failures
|
|
|
708 RESTARTABLE(::close(fd), result);
|
|
|
709 assert(result != OS_ERR, "could not close file");
|
|
|
710
|
|
|
711 if (mapAddress == MAP_FAILED) {
|
|
|
712 if (PrintMiscellaneous && Verbose) {
|
|
|
713 warning("mmap failed - %s\n", strerror(errno));
|
|
|
714 }
|
|
|
715 remove_file(filename);
|
|
|
716 FREE_C_HEAP_ARRAY(char, filename);
|
|
|
717 return NULL;
|
|
|
718 }
|
|
|
719
|
|
|
720 // save the file name for use in delete_shared_memory()
|
|
|
721 backing_store_file_name = filename;
|
|
|
722
|
|
|
723 // clear the shared memory region
|
|
|
724 (void)::memset((void*) mapAddress, 0, size);
|
|
|
725
|
|
|
726 return mapAddress;
|
|
|
727 }
|
|
|
728
|
|
|
729 // release a named shared memory region
|
|
|
730 //
|
|
|
731 static void unmap_shared(char* addr, size_t bytes) {
|
|
|
732 os::release_memory(addr, bytes);
|
|
|
733 }
|
|
|
734
|
|
|
735 // create the PerfData memory region in shared memory.
|
|
|
736 //
|
|
|
737 static char* create_shared_memory(size_t size) {
|
|
|
738
|
|
|
739 // create the shared memory region.
|
|
|
740 return mmap_create_shared(size);
|
|
|
741 }
|
|
|
742
|
|
|
743 // delete the shared PerfData memory region
|
|
|
744 //
|
|
|
745 static void delete_shared_memory(char* addr, size_t size) {
|
|
|
746
|
|
|
747 // cleanup the persistent shared memory resources. since DestroyJavaVM does
|
|
|
748 // not support unloading of the JVM, unmapping of the memory resource is
|
|
|
749 // not performed. The memory will be reclaimed by the OS upon termination of
|
|
|
750 // the process. The backing store file is deleted from the file system.
|
|
|
751
|
|
|
752 assert(!PerfDisableSharedMem, "shouldn't be here");
|
|
|
753
|
|
|
754 if (backing_store_file_name != NULL) {
|
|
|
755 remove_file(backing_store_file_name);
|
|
|
756 // Don't.. Free heap memory could deadlock os::abort() if it is called
|
|
|
757 // from signal handler. OS will reclaim the heap memory.
|
|
|
758 // FREE_C_HEAP_ARRAY(char, backing_store_file_name);
|
|
|
759 backing_store_file_name = NULL;
|
|
|
760 }
|
|
|
761 }
|
|
|
762
|
|
|
763 // return the size of the file for the given file descriptor
|
|
|
764 // or 0 if it is not a valid size for a shared memory file
|
|
|
765 //
|
|
|
766 static size_t sharedmem_filesize(int fd, TRAPS) {
|
|
|
767
|
|
|
768 struct stat statbuf;
|
|
|
769 int result;
|
|
|
770
|
|
|
771 RESTARTABLE(::fstat(fd, &statbuf), result);
|
|
|
772 if (result == OS_ERR) {
|
|
|
773 if (PrintMiscellaneous && Verbose) {
|
|
|
774 warning("fstat failed: %s\n", strerror(errno));
|
|
|
775 }
|
|
|
776 THROW_MSG_0(vmSymbols::java_io_IOException(),
|
|
|
777 "Could not determine PerfMemory size");
|
|
|
778 }
|
|
|
779
|
|
|
780 if ((statbuf.st_size == 0) ||
|
|
|
781 ((size_t)statbuf.st_size % os::vm_page_size() != 0)) {
|
|
|
782 THROW_MSG_0(vmSymbols::java_lang_Exception(),
|
|
|
783 "Invalid PerfMemory size");
|
|
|
784 }
|
|
|
785
|
|
|
786 return (size_t)statbuf.st_size;
|
|
|
787 }
|
|
|
788
|
|
|
789 // attach to a named shared memory region.
|
|
|
790 //
|
|
|
791 static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemoryMode mode, char** addr, size_t* sizep, TRAPS) {
|
|
|
792
|
|
|
793 char* mapAddress;
|
|
|
794 int result;
|
|
|
795 int fd;
|
|
|
796 size_t size;
|
|
|
797 const char* luser = NULL;
|
|
|
798
|
|
|
799 int mmap_prot;
|
|
|
800 int file_flags;
|
|
|
801
|
|
|
802 ResourceMark rm;
|
|
|
803
|
|
|
804 // map the high level access mode to the appropriate permission
|
|
|
805 // constructs for the file and the shared memory mapping.
|
|
|
806 if (mode == PerfMemory::PERF_MODE_RO) {
|
|
|
807 mmap_prot = PROT_READ;
|
|
|
808 file_flags = O_RDONLY;
|
|
|
809 }
|
|
|
810 else if (mode == PerfMemory::PERF_MODE_RW) {
|
|
|
811 #ifdef LATER
|
|
|
812 mmap_prot = PROT_READ | PROT_WRITE;
|
|
|
813 file_flags = O_RDWR;
|
|
|
814 #else
|
|
|
815 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
|
|
|
816 "Unsupported access mode");
|
|
|
817 #endif
|
|
|
818 }
|
|
|
819 else {
|
|
|
820 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
|
|
|
821 "Illegal access mode");
|
|
|
822 }
|
|
|
823
|
|
|
824 if (user == NULL || strlen(user) == 0) {
|
|
|
825 luser = get_user_name(vmid, CHECK);
|
|
|
826 }
|
|
|
827 else {
|
|
|
828 luser = user;
|
|
|
829 }
|
|
|
830
|
|
|
831 if (luser == NULL) {
|
|
|
832 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
|
|
|
833 "Could not map vmid to user Name");
|
|
|
834 }
|
|
|
835
|
|
|
836 char* dirname = get_user_tmp_dir(luser);
|
|
|
837
|
|
|
838 // since we don't follow symbolic links when creating the backing
|
|
|
839 // store file, we don't follow them when attaching either.
|
|
|
840 //
|
|
|
841 if (!is_directory_secure(dirname)) {
|
|
|
842 FREE_C_HEAP_ARRAY(char, dirname);
|
|
|
843 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
|
|
|
844 "Process not found");
|
|
|
845 }
|
|
|
846
|
|
|
847 char* filename = get_sharedmem_filename(dirname, vmid);
|
|
|
848
|
|
|
849 // copy heap memory to resource memory. the open_sharedmem_file
|
|
|
850 // method below need to use the filename, but could throw an
|
|
|
851 // exception. using a resource array prevents the leak that
|
|
|
852 // would otherwise occur.
|
|
|
853 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1);
|
|
|
854 strcpy(rfilename, filename);
|
|
|
855
|
|
|
856 // free the c heap resources that are no longer needed
|
|
|
857 if (luser != user) FREE_C_HEAP_ARRAY(char, luser);
|
|
|
858 FREE_C_HEAP_ARRAY(char, dirname);
|
|
|
859 FREE_C_HEAP_ARRAY(char, filename);
|
|
|
860
|
|
|
861 // open the shared memory file for the give vmid
|
|
|
862 fd = open_sharedmem_file(rfilename, file_flags, CHECK);
|
|
|
863 assert(fd != OS_ERR, "unexpected value");
|
|
|
864
|
|
|
865 if (*sizep == 0) {
|
|
|
866 size = sharedmem_filesize(fd, CHECK);
|
|
|
867 assert(size != 0, "unexpected size");
|
|
|
868 }
|
|
|
869
|
|
|
870 mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0);
|
|
|
871
|
|
|
872 // attempt to close the file - restart if it gets interrupted,
|
|
|
873 // but ignore other failures
|
|
|
874 RESTARTABLE(::close(fd), result);
|
|
|
875 assert(result != OS_ERR, "could not close file");
|
|
|
876
|
|
|
877 if (mapAddress == MAP_FAILED) {
|
|
|
878 if (PrintMiscellaneous && Verbose) {
|
|
|
879 warning("mmap failed: %s\n", strerror(errno));
|
|
|
880 }
|
|
|
881 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(),
|
|
|
882 "Could not map PerfMemory");
|
|
|
883 }
|
|
|
884
|
|
|
885 *addr = mapAddress;
|
|
|
886 *sizep = size;
|
|
|
887
|
|
|
888 if (PerfTraceMemOps) {
|
|
|
889 tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at "
|
|
|
890 INTPTR_FORMAT "\n", size, vmid, (void*)mapAddress);
|
|
|
891 }
|
|
|
892 }
|
|
|
893
|
|
|
894
|
|
|
895
|
|
|
896
|
|
|
897 // create the PerfData memory region
|
|
|
898 //
|
|
|
899 // This method creates the memory region used to store performance
|
|
|
900 // data for the JVM. The memory may be created in standard or
|
|
|
901 // shared memory.
|
|
|
902 //
|
|
|
903 void PerfMemory::create_memory_region(size_t size) {
|
|
|
904
|
|
|
905 if (PerfDisableSharedMem) {
|
|
|
906 // do not share the memory for the performance data.
|
|
|
907 _start = create_standard_memory(size);
|
|
|
908 }
|
|
|
909 else {
|
|
|
910 _start = create_shared_memory(size);
|
|
|
911 if (_start == NULL) {
|
|
|
912
|
|
|
913 // creation of the shared memory region failed, attempt
|
|
|
914 // to create a contiguous, non-shared memory region instead.
|
|
|
915 //
|
|
|
916 if (PrintMiscellaneous && Verbose) {
|
|
|
917 warning("Reverting to non-shared PerfMemory region.\n");
|
|
|
918 }
|
|
|
919 PerfDisableSharedMem = true;
|
|
|
920 _start = create_standard_memory(size);
|
|
|
921 }
|
|
|
922 }
|
|
|
923
|
|
|
924 if (_start != NULL) _capacity = size;
|
|
|
925
|
|
|
926 }
|
|
|
927
|
|
|
928 // delete the PerfData memory region
|
|
|
929 //
|
|
|
930 // This method deletes the memory region used to store performance
|
|
|
931 // data for the JVM. The memory region indicated by the <address, size>
|
|
|
932 // tuple will be inaccessible after a call to this method.
|
|
|
933 //
|
|
|
934 void PerfMemory::delete_memory_region() {
|
|
|
935
|
|
|
936 assert((start() != NULL && capacity() > 0), "verify proper state");
|
|
|
937
|
|
|
938 // If user specifies PerfDataSaveFile, it will save the performance data
|
|
|
939 // to the specified file name no matter whether PerfDataSaveToFile is specified
|
|
|
940 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag
|
|
|
941 // -XX:+PerfDataSaveToFile.
|
|
|
942 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) {
|
|
|
943 save_memory_to_file(start(), capacity());
|
|
|
944 }
|
|
|
945
|
|
|
946 if (PerfDisableSharedMem) {
|
|
|
947 delete_standard_memory(start(), capacity());
|
|
|
948 }
|
|
|
949 else {
|
|
|
950 delete_shared_memory(start(), capacity());
|
|
|
951 }
|
|
|
952 }
|
|
|
953
|
|
|
954 // attach to the PerfData memory region for another JVM
|
|
|
955 //
|
|
|
956 // This method returns an <address, size> tuple that points to
|
|
|
957 // a memory buffer that is kept reasonably synchronized with
|
|
|
958 // the PerfData memory region for the indicated JVM. This
|
|
|
959 // buffer may be kept in synchronization via shared memory
|
|
|
960 // or some other mechanism that keeps the buffer updated.
|
|
|
961 //
|
|
|
962 // If the JVM chooses not to support the attachability feature,
|
|
|
963 // this method should throw an UnsupportedOperation exception.
|
|
|
964 //
|
|
|
965 // This implementation utilizes named shared memory to map
|
|
|
966 // the indicated process's PerfData memory region into this JVMs
|
|
|
967 // address space.
|
|
|
968 //
|
|
|
969 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, char** addrp, size_t* sizep, TRAPS) {
|
|
|
970
|
|
|
971 if (vmid == 0 || vmid == os::current_process_id()) {
|
|
|
972 *addrp = start();
|
|
|
973 *sizep = capacity();
|
|
|
974 return;
|
|
|
975 }
|
|
|
976
|
|
|
977 mmap_attach_shared(user, vmid, mode, addrp, sizep, CHECK);
|
|
|
978 }
|
|
|
979
|
|
|
980 // detach from the PerfData memory region of another JVM
|
|
|
981 //
|
|
|
982 // This method detaches the PerfData memory region of another
|
|
|
983 // JVM, specified as an <address, size> tuple of a buffer
|
|
|
984 // in this process's address space. This method may perform
|
|
|
985 // arbitrary actions to accomplish the detachment. The memory
|
|
|
986 // region specified by <address, size> will be inaccessible after
|
|
|
987 // a call to this method.
|
|
|
988 //
|
|
|
989 // If the JVM chooses not to support the attachability feature,
|
|
|
990 // this method should throw an UnsupportedOperation exception.
|
|
|
991 //
|
|
|
992 // This implementation utilizes named shared memory to detach
|
|
|
993 // the indicated process's PerfData memory region from this
|
|
|
994 // process's address space.
|
|
|
995 //
|
|
|
996 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) {
|
|
|
997
|
|
|
998 assert(addr != 0, "address sanity check");
|
|
|
999 assert(bytes > 0, "capacity sanity check");
|
|
|
1000
|
|
|
1001 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) {
|
|
|
1002 // prevent accidental detachment of this process's PerfMemory region
|
|
|
1003 return;
|
|
|
1004 }
|
|
|
1005
|
|
|
1006 unmap_shared(addr, bytes);
|
|
|
1007 }
|
|
|
1008
|
|
|
1009 char* PerfMemory::backing_store_filename() {
|
|
|
1010 return backing_store_file_name;
|
|
|
1011 }
|
