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1 /* |
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2 * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved. |
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3 * Copyright 2012, 2013 SAP AG. All rights reserved. |
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4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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5 * |
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6 * This code is free software; you can redistribute it and/or modify it |
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7 * under the terms of the GNU General Public License version 2 only, as |
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8 * published by the Free Software Foundation. |
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9 * |
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10 * This code is distributed in the hope that it will be useful, but WITHOUT |
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11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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13 * version 2 for more details (a copy is included in the LICENSE file that |
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14 * accompanied this code). |
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15 * |
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16 * You should have received a copy of the GNU General Public License version |
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17 * 2 along with this work; if not, write to the Free Software Foundation, |
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18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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19 * |
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20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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21 * or visit www.oracle.com if you need additional information or have any |
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22 * questions. |
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23 * |
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24 */ |
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25 |
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26 #include "precompiled.hpp" |
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27 #include "classfile/vmSymbols.hpp" |
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28 #include "memory/allocation.inline.hpp" |
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29 #include "memory/resourceArea.hpp" |
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30 #include "oops/oop.inline.hpp" |
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31 #include "os_aix.inline.hpp" |
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32 #include "runtime/handles.inline.hpp" |
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33 #include "runtime/perfMemory.hpp" |
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34 #include "utilities/exceptions.hpp" |
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35 |
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36 // put OS-includes here |
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37 # include <sys/types.h> |
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38 # include <sys/mman.h> |
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39 # include <errno.h> |
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40 # include <stdio.h> |
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41 # include <unistd.h> |
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42 # include <sys/stat.h> |
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43 # include <signal.h> |
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44 # include <pwd.h> |
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45 |
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46 static char* backing_store_file_name = NULL; // name of the backing store |
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47 // file, if successfully created. |
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48 |
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49 // Standard Memory Implementation Details |
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50 |
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51 // create the PerfData memory region in standard memory. |
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52 // |
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53 static char* create_standard_memory(size_t size) { |
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54 |
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55 // allocate an aligned chuck of memory |
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56 char* mapAddress = os::reserve_memory(size); |
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57 |
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58 if (mapAddress == NULL) { |
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59 return NULL; |
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60 } |
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61 |
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62 // commit memory |
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63 if (!os::commit_memory(mapAddress, size, !ExecMem)) { |
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64 if (PrintMiscellaneous && Verbose) { |
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65 warning("Could not commit PerfData memory\n"); |
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66 } |
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67 os::release_memory(mapAddress, size); |
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68 return NULL; |
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69 } |
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70 |
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71 return mapAddress; |
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72 } |
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73 |
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74 // delete the PerfData memory region |
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75 // |
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76 static void delete_standard_memory(char* addr, size_t size) { |
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77 |
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78 // there are no persistent external resources to cleanup for standard |
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79 // memory. since DestroyJavaVM does not support unloading of the JVM, |
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80 // cleanup of the memory resource is not performed. The memory will be |
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81 // reclaimed by the OS upon termination of the process. |
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82 // |
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83 return; |
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84 } |
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85 |
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86 // save the specified memory region to the given file |
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87 // |
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88 // Note: this function might be called from signal handler (by os::abort()), |
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89 // don't allocate heap memory. |
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90 // |
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91 static void save_memory_to_file(char* addr, size_t size) { |
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92 |
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93 const char* destfile = PerfMemory::get_perfdata_file_path(); |
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94 assert(destfile[0] != '\0', "invalid PerfData file path"); |
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95 |
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96 int result; |
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97 |
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98 RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE), |
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99 result);; |
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100 if (result == OS_ERR) { |
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101 if (PrintMiscellaneous && Verbose) { |
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102 warning("Could not create Perfdata save file: %s: %s\n", |
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103 destfile, strerror(errno)); |
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104 } |
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105 } else { |
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106 int fd = result; |
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107 |
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108 for (size_t remaining = size; remaining > 0;) { |
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109 |
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110 RESTARTABLE(::write(fd, addr, remaining), result); |
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111 if (result == OS_ERR) { |
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112 if (PrintMiscellaneous && Verbose) { |
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113 warning("Could not write Perfdata save file: %s: %s\n", |
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114 destfile, strerror(errno)); |
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115 } |
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116 break; |
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117 } |
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118 |
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119 remaining -= (size_t)result; |
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120 addr += result; |
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121 } |
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122 |
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123 RESTARTABLE(::close(fd), result); |
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124 if (PrintMiscellaneous && Verbose) { |
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125 if (result == OS_ERR) { |
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126 warning("Could not close %s: %s\n", destfile, strerror(errno)); |
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127 } |
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128 } |
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129 } |
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130 FREE_C_HEAP_ARRAY(char, destfile, mtInternal); |
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131 } |
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132 |
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133 |
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134 // Shared Memory Implementation Details |
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135 |
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136 // Note: the solaris and linux shared memory implementation uses the mmap |
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137 // interface with a backing store file to implement named shared memory. |
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138 // Using the file system as the name space for shared memory allows a |
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139 // common name space to be supported across a variety of platforms. It |
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140 // also provides a name space that Java applications can deal with through |
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141 // simple file apis. |
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142 // |
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143 // The solaris and linux implementations store the backing store file in |
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144 // a user specific temporary directory located in the /tmp file system, |
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145 // which is always a local file system and is sometimes a RAM based file |
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146 // system. |
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147 |
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148 // return the user specific temporary directory name. |
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149 // |
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150 // the caller is expected to free the allocated memory. |
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151 // |
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152 static char* get_user_tmp_dir(const char* user) { |
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153 |
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154 const char* tmpdir = os::get_temp_directory(); |
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155 const char* perfdir = PERFDATA_NAME; |
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156 size_t nbytes = strlen(tmpdir) + strlen(perfdir) + strlen(user) + 3; |
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157 char* dirname = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal); |
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158 |
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159 // construct the path name to user specific tmp directory |
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160 snprintf(dirname, nbytes, "%s/%s_%s", tmpdir, perfdir, user); |
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161 |
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162 return dirname; |
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163 } |
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164 |
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165 // convert the given file name into a process id. if the file |
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166 // does not meet the file naming constraints, return 0. |
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167 // |
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168 static pid_t filename_to_pid(const char* filename) { |
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169 |
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170 // a filename that doesn't begin with a digit is not a |
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171 // candidate for conversion. |
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172 // |
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173 if (!isdigit(*filename)) { |
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174 return 0; |
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175 } |
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176 |
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177 // check if file name can be converted to an integer without |
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178 // any leftover characters. |
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179 // |
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180 char* remainder = NULL; |
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181 errno = 0; |
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182 pid_t pid = (pid_t)strtol(filename, &remainder, 10); |
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183 |
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184 if (errno != 0) { |
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185 return 0; |
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186 } |
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187 |
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188 // check for left over characters. If any, then the filename is |
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189 // not a candidate for conversion. |
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190 // |
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191 if (remainder != NULL && *remainder != '\0') { |
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192 return 0; |
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193 } |
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194 |
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195 // successful conversion, return the pid |
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196 return pid; |
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197 } |
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198 |
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199 |
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200 // check if the given path is considered a secure directory for |
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201 // the backing store files. Returns true if the directory exists |
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202 // and is considered a secure location. Returns false if the path |
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203 // is a symbolic link or if an error occurred. |
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204 // |
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205 static bool is_directory_secure(const char* path) { |
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206 struct stat statbuf; |
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207 int result = 0; |
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208 |
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209 RESTARTABLE(::lstat(path, &statbuf), result); |
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210 if (result == OS_ERR) { |
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211 return false; |
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212 } |
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213 |
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214 // the path exists, now check it's mode |
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215 if (S_ISLNK(statbuf.st_mode) || !S_ISDIR(statbuf.st_mode)) { |
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216 // the path represents a link or some non-directory file type, |
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217 // which is not what we expected. declare it insecure. |
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218 // |
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219 return false; |
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220 } |
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221 else { |
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222 // we have an existing directory, check if the permissions are safe. |
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223 // |
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224 if ((statbuf.st_mode & (S_IWGRP|S_IWOTH)) != 0) { |
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225 // the directory is open for writing and could be subjected |
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226 // to a symlnk attack. declare it insecure. |
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227 // |
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228 return false; |
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229 } |
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230 } |
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231 return true; |
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232 } |
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233 |
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234 |
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235 // return the user name for the given user id |
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236 // |
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237 // the caller is expected to free the allocated memory. |
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238 // |
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239 static char* get_user_name(uid_t uid) { |
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240 |
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241 struct passwd pwent; |
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242 |
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243 // determine the max pwbuf size from sysconf, and hardcode |
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244 // a default if this not available through sysconf. |
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245 // |
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246 long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX); |
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247 if (bufsize == -1) |
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248 bufsize = 1024; |
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249 |
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250 char* pwbuf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); |
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251 |
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252 // POSIX interface to getpwuid_r is used on LINUX |
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253 struct passwd* p; |
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254 int result = getpwuid_r(uid, &pwent, pwbuf, (size_t)bufsize, &p); |
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255 |
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256 if (result != 0 || p == NULL || p->pw_name == NULL || *(p->pw_name) == '\0') { |
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257 if (PrintMiscellaneous && Verbose) { |
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258 if (result != 0) { |
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259 warning("Could not retrieve passwd entry: %s\n", |
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260 strerror(result)); |
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261 } |
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262 else if (p == NULL) { |
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263 // this check is added to protect against an observed problem |
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264 // with getpwuid_r() on RedHat 9 where getpwuid_r returns 0, |
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265 // indicating success, but has p == NULL. This was observed when |
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266 // inserting a file descriptor exhaustion fault prior to the call |
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267 // getpwuid_r() call. In this case, error is set to the appropriate |
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268 // error condition, but this is undocumented behavior. This check |
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269 // is safe under any condition, but the use of errno in the output |
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270 // message may result in an erroneous message. |
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271 // Bug Id 89052 was opened with RedHat. |
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272 // |
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273 warning("Could not retrieve passwd entry: %s\n", |
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274 strerror(errno)); |
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275 } |
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276 else { |
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277 warning("Could not determine user name: %s\n", |
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278 p->pw_name == NULL ? "pw_name = NULL" : |
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279 "pw_name zero length"); |
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280 } |
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281 } |
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282 FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal); |
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283 return NULL; |
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284 } |
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285 |
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286 char* user_name = NEW_C_HEAP_ARRAY(char, strlen(p->pw_name) + 1, mtInternal); |
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287 strcpy(user_name, p->pw_name); |
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288 |
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289 FREE_C_HEAP_ARRAY(char, pwbuf, mtInternal); |
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290 return user_name; |
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291 } |
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292 |
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293 // return the name of the user that owns the process identified by vmid. |
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294 // |
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295 // This method uses a slow directory search algorithm to find the backing |
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296 // store file for the specified vmid and returns the user name, as determined |
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297 // by the user name suffix of the hsperfdata_<username> directory name. |
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298 // |
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299 // the caller is expected to free the allocated memory. |
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300 // |
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301 static char* get_user_name_slow(int vmid, TRAPS) { |
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302 |
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303 // short circuit the directory search if the process doesn't even exist. |
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304 if (kill(vmid, 0) == OS_ERR) { |
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305 if (errno == ESRCH) { |
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306 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), |
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307 "Process not found"); |
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308 } |
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309 else /* EPERM */ { |
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310 THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno)); |
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311 } |
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312 } |
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313 |
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314 // directory search |
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315 char* oldest_user = NULL; |
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316 time_t oldest_ctime = 0; |
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317 |
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318 const char* tmpdirname = os::get_temp_directory(); |
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319 |
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320 DIR* tmpdirp = os::opendir(tmpdirname); |
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321 |
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322 if (tmpdirp == NULL) { |
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323 return NULL; |
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324 } |
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325 |
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326 // for each entry in the directory that matches the pattern hsperfdata_*, |
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327 // open the directory and check if the file for the given vmid exists. |
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328 // The file with the expected name and the latest creation date is used |
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329 // to determine the user name for the process id. |
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330 // |
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331 struct dirent* dentry; |
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332 char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname), mtInternal); |
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333 errno = 0; |
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334 while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) { |
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335 |
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336 // check if the directory entry is a hsperfdata file |
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337 if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) { |
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338 continue; |
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339 } |
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340 |
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341 char* usrdir_name = NEW_C_HEAP_ARRAY(char, |
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342 strlen(tmpdirname) + strlen(dentry->d_name) + 2, mtInternal); |
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343 strcpy(usrdir_name, tmpdirname); |
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344 strcat(usrdir_name, "/"); |
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345 strcat(usrdir_name, dentry->d_name); |
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346 |
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347 DIR* subdirp = os::opendir(usrdir_name); |
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348 |
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349 if (subdirp == NULL) { |
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350 FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal); |
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351 continue; |
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352 } |
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353 |
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354 // Since we don't create the backing store files in directories |
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355 // pointed to by symbolic links, we also don't follow them when |
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356 // looking for the files. We check for a symbolic link after the |
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357 // call to opendir in order to eliminate a small window where the |
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358 // symlink can be exploited. |
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359 // |
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360 if (!is_directory_secure(usrdir_name)) { |
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361 FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal); |
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362 os::closedir(subdirp); |
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363 continue; |
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364 } |
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365 |
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366 struct dirent* udentry; |
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367 char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name), mtInternal); |
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368 errno = 0; |
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369 while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) { |
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370 |
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371 if (filename_to_pid(udentry->d_name) == vmid) { |
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372 struct stat statbuf; |
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373 int result; |
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374 |
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375 char* filename = NEW_C_HEAP_ARRAY(char, |
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376 strlen(usrdir_name) + strlen(udentry->d_name) + 2, mtInternal); |
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377 |
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378 strcpy(filename, usrdir_name); |
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379 strcat(filename, "/"); |
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380 strcat(filename, udentry->d_name); |
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381 |
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382 // don't follow symbolic links for the file |
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383 RESTARTABLE(::lstat(filename, &statbuf), result); |
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384 if (result == OS_ERR) { |
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385 FREE_C_HEAP_ARRAY(char, filename, mtInternal); |
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386 continue; |
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387 } |
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388 |
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389 // skip over files that are not regular files. |
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390 if (!S_ISREG(statbuf.st_mode)) { |
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391 FREE_C_HEAP_ARRAY(char, filename, mtInternal); |
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392 continue; |
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393 } |
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394 |
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395 // compare and save filename with latest creation time |
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396 if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) { |
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397 |
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398 if (statbuf.st_ctime > oldest_ctime) { |
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399 char* user = strchr(dentry->d_name, '_') + 1; |
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400 |
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401 if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user, mtInternal); |
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402 oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal); |
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403 |
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404 strcpy(oldest_user, user); |
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405 oldest_ctime = statbuf.st_ctime; |
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406 } |
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407 } |
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408 |
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409 FREE_C_HEAP_ARRAY(char, filename, mtInternal); |
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410 } |
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411 } |
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412 os::closedir(subdirp); |
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413 FREE_C_HEAP_ARRAY(char, udbuf, mtInternal); |
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414 FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal); |
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415 } |
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416 os::closedir(tmpdirp); |
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417 FREE_C_HEAP_ARRAY(char, tdbuf, mtInternal); |
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418 |
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419 return(oldest_user); |
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420 } |
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421 |
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422 // return the name of the user that owns the JVM indicated by the given vmid. |
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423 // |
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424 static char* get_user_name(int vmid, TRAPS) { |
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425 return get_user_name_slow(vmid, CHECK_NULL); |
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426 } |
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427 |
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428 // return the file name of the backing store file for the named |
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429 // shared memory region for the given user name and vmid. |
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430 // |
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431 // the caller is expected to free the allocated memory. |
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432 // |
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433 static char* get_sharedmem_filename(const char* dirname, int vmid) { |
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434 |
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435 // add 2 for the file separator and a null terminator. |
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436 size_t nbytes = strlen(dirname) + UINT_CHARS + 2; |
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437 |
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438 char* name = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal); |
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439 snprintf(name, nbytes, "%s/%d", dirname, vmid); |
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440 |
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441 return name; |
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442 } |
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443 |
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444 |
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445 // remove file |
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446 // |
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447 // this method removes the file specified by the given path |
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448 // |
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449 static void remove_file(const char* path) { |
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450 |
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451 int result; |
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452 |
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453 // if the file is a directory, the following unlink will fail. since |
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454 // we don't expect to find directories in the user temp directory, we |
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455 // won't try to handle this situation. even if accidentially or |
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456 // maliciously planted, the directory's presence won't hurt anything. |
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457 // |
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458 RESTARTABLE(::unlink(path), result); |
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459 if (PrintMiscellaneous && Verbose && result == OS_ERR) { |
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460 if (errno != ENOENT) { |
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461 warning("Could not unlink shared memory backing" |
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462 " store file %s : %s\n", path, strerror(errno)); |
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463 } |
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464 } |
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465 } |
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466 |
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467 |
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468 // remove file |
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469 // |
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470 // this method removes the file with the given file name in the |
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471 // named directory. |
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472 // |
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473 static void remove_file(const char* dirname, const char* filename) { |
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474 |
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475 size_t nbytes = strlen(dirname) + strlen(filename) + 2; |
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476 char* path = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal); |
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477 |
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478 strcpy(path, dirname); |
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479 strcat(path, "/"); |
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480 strcat(path, filename); |
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481 |
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482 remove_file(path); |
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483 |
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484 FREE_C_HEAP_ARRAY(char, path, mtInternal); |
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485 } |
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486 |
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487 |
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488 // cleanup stale shared memory resources |
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489 // |
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490 // This method attempts to remove all stale shared memory files in |
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491 // the named user temporary directory. It scans the named directory |
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492 // for files matching the pattern ^$[0-9]*$. For each file found, the |
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493 // process id is extracted from the file name and a test is run to |
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494 // determine if the process is alive. If the process is not alive, |
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495 // any stale file resources are removed. |
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496 // |
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497 static void cleanup_sharedmem_resources(const char* dirname) { |
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498 |
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499 // open the user temp directory |
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500 DIR* dirp = os::opendir(dirname); |
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501 |
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502 if (dirp == NULL) { |
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503 // directory doesn't exist, so there is nothing to cleanup |
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504 return; |
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505 } |
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506 |
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507 if (!is_directory_secure(dirname)) { |
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508 // the directory is not a secure directory |
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509 return; |
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510 } |
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511 |
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512 // for each entry in the directory that matches the expected file |
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513 // name pattern, determine if the file resources are stale and if |
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514 // so, remove the file resources. Note, instrumented HotSpot processes |
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515 // for this user may start and/or terminate during this search and |
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516 // remove or create new files in this directory. The behavior of this |
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517 // loop under these conditions is dependent upon the implementation of |
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518 // opendir/readdir. |
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519 // |
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520 struct dirent* entry; |
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521 char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname), mtInternal); |
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522 errno = 0; |
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523 while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) { |
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524 |
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525 pid_t pid = filename_to_pid(entry->d_name); |
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526 |
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527 if (pid == 0) { |
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528 |
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529 if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) { |
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530 |
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531 // attempt to remove all unexpected files, except "." and ".." |
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532 remove_file(dirname, entry->d_name); |
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533 } |
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534 |
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535 errno = 0; |
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536 continue; |
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537 } |
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538 |
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539 // we now have a file name that converts to a valid integer |
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540 // that could represent a process id . if this process id |
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541 // matches the current process id or the process is not running, |
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542 // then remove the stale file resources. |
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543 // |
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544 // process liveness is detected by sending signal number 0 to |
|
545 // the process id (see kill(2)). if kill determines that the |
|
546 // process does not exist, then the file resources are removed. |
|
547 // if kill determines that that we don't have permission to |
|
548 // signal the process, then the file resources are assumed to |
|
549 // be stale and are removed because the resources for such a |
|
550 // process should be in a different user specific directory. |
|
551 // |
|
552 if ((pid == os::current_process_id()) || |
|
553 (kill(pid, 0) == OS_ERR && (errno == ESRCH || errno == EPERM))) { |
|
554 |
|
555 remove_file(dirname, entry->d_name); |
|
556 } |
|
557 errno = 0; |
|
558 } |
|
559 os::closedir(dirp); |
|
560 FREE_C_HEAP_ARRAY(char, dbuf, mtInternal); |
|
561 } |
|
562 |
|
563 // make the user specific temporary directory. Returns true if |
|
564 // the directory exists and is secure upon return. Returns false |
|
565 // if the directory exists but is either a symlink, is otherwise |
|
566 // insecure, or if an error occurred. |
|
567 // |
|
568 static bool make_user_tmp_dir(const char* dirname) { |
|
569 |
|
570 // create the directory with 0755 permissions. note that the directory |
|
571 // will be owned by euid::egid, which may not be the same as uid::gid. |
|
572 // |
|
573 if (mkdir(dirname, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) == OS_ERR) { |
|
574 if (errno == EEXIST) { |
|
575 // The directory already exists and was probably created by another |
|
576 // JVM instance. However, this could also be the result of a |
|
577 // deliberate symlink. Verify that the existing directory is safe. |
|
578 // |
|
579 if (!is_directory_secure(dirname)) { |
|
580 // directory is not secure |
|
581 if (PrintMiscellaneous && Verbose) { |
|
582 warning("%s directory is insecure\n", dirname); |
|
583 } |
|
584 return false; |
|
585 } |
|
586 } |
|
587 else { |
|
588 // we encountered some other failure while attempting |
|
589 // to create the directory |
|
590 // |
|
591 if (PrintMiscellaneous && Verbose) { |
|
592 warning("could not create directory %s: %s\n", |
|
593 dirname, strerror(errno)); |
|
594 } |
|
595 return false; |
|
596 } |
|
597 } |
|
598 return true; |
|
599 } |
|
600 |
|
601 // create the shared memory file resources |
|
602 // |
|
603 // This method creates the shared memory file with the given size |
|
604 // This method also creates the user specific temporary directory, if |
|
605 // it does not yet exist. |
|
606 // |
|
607 static int create_sharedmem_resources(const char* dirname, const char* filename, size_t size) { |
|
608 |
|
609 // make the user temporary directory |
|
610 if (!make_user_tmp_dir(dirname)) { |
|
611 // could not make/find the directory or the found directory |
|
612 // was not secure |
|
613 return -1; |
|
614 } |
|
615 |
|
616 int result; |
|
617 |
|
618 RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_TRUNC, S_IREAD|S_IWRITE), result); |
|
619 if (result == OS_ERR) { |
|
620 if (PrintMiscellaneous && Verbose) { |
|
621 warning("could not create file %s: %s\n", filename, strerror(errno)); |
|
622 } |
|
623 return -1; |
|
624 } |
|
625 |
|
626 // save the file descriptor |
|
627 int fd = result; |
|
628 |
|
629 // set the file size |
|
630 RESTARTABLE(::ftruncate(fd, (off_t)size), result); |
|
631 if (result == OS_ERR) { |
|
632 if (PrintMiscellaneous && Verbose) { |
|
633 warning("could not set shared memory file size: %s\n", strerror(errno)); |
|
634 } |
|
635 RESTARTABLE(::close(fd), result); |
|
636 return -1; |
|
637 } |
|
638 |
|
639 return fd; |
|
640 } |
|
641 |
|
642 // open the shared memory file for the given user and vmid. returns |
|
643 // the file descriptor for the open file or -1 if the file could not |
|
644 // be opened. |
|
645 // |
|
646 static int open_sharedmem_file(const char* filename, int oflags, TRAPS) { |
|
647 |
|
648 // open the file |
|
649 int result; |
|
650 RESTARTABLE(::open(filename, oflags), result); |
|
651 if (result == OS_ERR) { |
|
652 if (errno == ENOENT) { |
|
653 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), |
|
654 "Process not found"); |
|
655 } |
|
656 else if (errno == EACCES) { |
|
657 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), |
|
658 "Permission denied"); |
|
659 } |
|
660 else { |
|
661 THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno)); |
|
662 } |
|
663 } |
|
664 |
|
665 return result; |
|
666 } |
|
667 |
|
668 // create a named shared memory region. returns the address of the |
|
669 // memory region on success or NULL on failure. A return value of |
|
670 // NULL will ultimately disable the shared memory feature. |
|
671 // |
|
672 // On Solaris and Linux, the name space for shared memory objects |
|
673 // is the file system name space. |
|
674 // |
|
675 // A monitoring application attaching to a JVM does not need to know |
|
676 // the file system name of the shared memory object. However, it may |
|
677 // be convenient for applications to discover the existence of newly |
|
678 // created and terminating JVMs by watching the file system name space |
|
679 // for files being created or removed. |
|
680 // |
|
681 static char* mmap_create_shared(size_t size) { |
|
682 |
|
683 int result; |
|
684 int fd; |
|
685 char* mapAddress; |
|
686 |
|
687 int vmid = os::current_process_id(); |
|
688 |
|
689 char* user_name = get_user_name(geteuid()); |
|
690 |
|
691 if (user_name == NULL) |
|
692 return NULL; |
|
693 |
|
694 char* dirname = get_user_tmp_dir(user_name); |
|
695 char* filename = get_sharedmem_filename(dirname, vmid); |
|
696 |
|
697 // cleanup any stale shared memory files |
|
698 cleanup_sharedmem_resources(dirname); |
|
699 |
|
700 assert(((size > 0) && (size % os::vm_page_size() == 0)), |
|
701 "unexpected PerfMemory region size"); |
|
702 |
|
703 fd = create_sharedmem_resources(dirname, filename, size); |
|
704 |
|
705 FREE_C_HEAP_ARRAY(char, user_name, mtInternal); |
|
706 FREE_C_HEAP_ARRAY(char, dirname, mtInternal); |
|
707 |
|
708 if (fd == -1) { |
|
709 FREE_C_HEAP_ARRAY(char, filename, mtInternal); |
|
710 return NULL; |
|
711 } |
|
712 |
|
713 mapAddress = (char*)::mmap((char*)0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); |
|
714 |
|
715 // attempt to close the file - restart it if it was interrupted, |
|
716 // but ignore other failures |
|
717 RESTARTABLE(::close(fd), result); |
|
718 assert(result != OS_ERR, "could not close file"); |
|
719 |
|
720 if (mapAddress == MAP_FAILED) { |
|
721 if (PrintMiscellaneous && Verbose) { |
|
722 warning("mmap failed - %s\n", strerror(errno)); |
|
723 } |
|
724 remove_file(filename); |
|
725 FREE_C_HEAP_ARRAY(char, filename, mtInternal); |
|
726 return NULL; |
|
727 } |
|
728 |
|
729 // save the file name for use in delete_shared_memory() |
|
730 backing_store_file_name = filename; |
|
731 |
|
732 // clear the shared memory region |
|
733 (void)::memset((void*) mapAddress, 0, size); |
|
734 |
|
735 return mapAddress; |
|
736 } |
|
737 |
|
738 // release a named shared memory region |
|
739 // |
|
740 static void unmap_shared(char* addr, size_t bytes) { |
|
741 // Do not rely on os::reserve_memory/os::release_memory to use mmap. |
|
742 // Use os::reserve_memory/os::release_memory for PerfDisableSharedMem=1, mmap/munmap for PerfDisableSharedMem=0 |
|
743 if (::munmap(addr, bytes) == -1) { |
|
744 warning("perfmemory: munmap failed (%d)\n", errno); |
|
745 } |
|
746 } |
|
747 |
|
748 // create the PerfData memory region in shared memory. |
|
749 // |
|
750 static char* create_shared_memory(size_t size) { |
|
751 |
|
752 // create the shared memory region. |
|
753 return mmap_create_shared(size); |
|
754 } |
|
755 |
|
756 // delete the shared PerfData memory region |
|
757 // |
|
758 static void delete_shared_memory(char* addr, size_t size) { |
|
759 |
|
760 // cleanup the persistent shared memory resources. since DestroyJavaVM does |
|
761 // not support unloading of the JVM, unmapping of the memory resource is |
|
762 // not performed. The memory will be reclaimed by the OS upon termination of |
|
763 // the process. The backing store file is deleted from the file system. |
|
764 |
|
765 assert(!PerfDisableSharedMem, "shouldn't be here"); |
|
766 |
|
767 if (backing_store_file_name != NULL) { |
|
768 remove_file(backing_store_file_name); |
|
769 // Don't.. Free heap memory could deadlock os::abort() if it is called |
|
770 // from signal handler. OS will reclaim the heap memory. |
|
771 // FREE_C_HEAP_ARRAY(char, backing_store_file_name, mtInternal); |
|
772 backing_store_file_name = NULL; |
|
773 } |
|
774 } |
|
775 |
|
776 // return the size of the file for the given file descriptor |
|
777 // or 0 if it is not a valid size for a shared memory file |
|
778 // |
|
779 static size_t sharedmem_filesize(int fd, TRAPS) { |
|
780 |
|
781 struct stat statbuf; |
|
782 int result; |
|
783 |
|
784 RESTARTABLE(::fstat(fd, &statbuf), result); |
|
785 if (result == OS_ERR) { |
|
786 if (PrintMiscellaneous && Verbose) { |
|
787 warning("fstat failed: %s\n", strerror(errno)); |
|
788 } |
|
789 THROW_MSG_0(vmSymbols::java_io_IOException(), |
|
790 "Could not determine PerfMemory size"); |
|
791 } |
|
792 |
|
793 if ((statbuf.st_size == 0) || |
|
794 ((size_t)statbuf.st_size % os::vm_page_size() != 0)) { |
|
795 THROW_MSG_0(vmSymbols::java_lang_Exception(), |
|
796 "Invalid PerfMemory size"); |
|
797 } |
|
798 |
|
799 return (size_t)statbuf.st_size; |
|
800 } |
|
801 |
|
802 // attach to a named shared memory region. |
|
803 // |
|
804 static void mmap_attach_shared(const char* user, int vmid, PerfMemory::PerfMemoryMode mode, char** addr, size_t* sizep, TRAPS) { |
|
805 |
|
806 char* mapAddress; |
|
807 int result; |
|
808 int fd; |
|
809 size_t size; |
|
810 const char* luser = NULL; |
|
811 |
|
812 int mmap_prot; |
|
813 int file_flags; |
|
814 |
|
815 ResourceMark rm; |
|
816 |
|
817 // map the high level access mode to the appropriate permission |
|
818 // constructs for the file and the shared memory mapping. |
|
819 if (mode == PerfMemory::PERF_MODE_RO) { |
|
820 mmap_prot = PROT_READ; |
|
821 file_flags = O_RDONLY; |
|
822 } |
|
823 else if (mode == PerfMemory::PERF_MODE_RW) { |
|
824 #ifdef LATER |
|
825 mmap_prot = PROT_READ | PROT_WRITE; |
|
826 file_flags = O_RDWR; |
|
827 #else |
|
828 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), |
|
829 "Unsupported access mode"); |
|
830 #endif |
|
831 } |
|
832 else { |
|
833 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), |
|
834 "Illegal access mode"); |
|
835 } |
|
836 |
|
837 if (user == NULL || strlen(user) == 0) { |
|
838 luser = get_user_name(vmid, CHECK); |
|
839 } |
|
840 else { |
|
841 luser = user; |
|
842 } |
|
843 |
|
844 if (luser == NULL) { |
|
845 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), |
|
846 "Could not map vmid to user Name"); |
|
847 } |
|
848 |
|
849 char* dirname = get_user_tmp_dir(luser); |
|
850 |
|
851 // since we don't follow symbolic links when creating the backing |
|
852 // store file, we don't follow them when attaching either. |
|
853 // |
|
854 if (!is_directory_secure(dirname)) { |
|
855 FREE_C_HEAP_ARRAY(char, dirname, mtInternal); |
|
856 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), |
|
857 "Process not found"); |
|
858 } |
|
859 |
|
860 char* filename = get_sharedmem_filename(dirname, vmid); |
|
861 |
|
862 // copy heap memory to resource memory. the open_sharedmem_file |
|
863 // method below need to use the filename, but could throw an |
|
864 // exception. using a resource array prevents the leak that |
|
865 // would otherwise occur. |
|
866 char* rfilename = NEW_RESOURCE_ARRAY(char, strlen(filename) + 1); |
|
867 strcpy(rfilename, filename); |
|
868 |
|
869 // free the c heap resources that are no longer needed |
|
870 if (luser != user) FREE_C_HEAP_ARRAY(char, luser, mtInternal); |
|
871 FREE_C_HEAP_ARRAY(char, dirname, mtInternal); |
|
872 FREE_C_HEAP_ARRAY(char, filename, mtInternal); |
|
873 |
|
874 // open the shared memory file for the give vmid |
|
875 fd = open_sharedmem_file(rfilename, file_flags, CHECK); |
|
876 assert(fd != OS_ERR, "unexpected value"); |
|
877 |
|
878 if (*sizep == 0) { |
|
879 size = sharedmem_filesize(fd, CHECK); |
|
880 assert(size != 0, "unexpected size"); |
|
881 } else { |
|
882 size = *sizep; |
|
883 } |
|
884 |
|
885 mapAddress = (char*)::mmap((char*)0, size, mmap_prot, MAP_SHARED, fd, 0); |
|
886 |
|
887 // attempt to close the file - restart if it gets interrupted, |
|
888 // but ignore other failures |
|
889 RESTARTABLE(::close(fd), result); |
|
890 assert(result != OS_ERR, "could not close file"); |
|
891 |
|
892 if (mapAddress == MAP_FAILED) { |
|
893 if (PrintMiscellaneous && Verbose) { |
|
894 warning("mmap failed: %s\n", strerror(errno)); |
|
895 } |
|
896 THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(), |
|
897 "Could not map PerfMemory"); |
|
898 } |
|
899 |
|
900 *addr = mapAddress; |
|
901 *sizep = size; |
|
902 |
|
903 if (PerfTraceMemOps) { |
|
904 tty->print("mapped " SIZE_FORMAT " bytes for vmid %d at " |
|
905 INTPTR_FORMAT "\n", size, vmid, (void*)mapAddress); |
|
906 } |
|
907 } |
|
908 |
|
909 |
|
910 |
|
911 |
|
912 // create the PerfData memory region |
|
913 // |
|
914 // This method creates the memory region used to store performance |
|
915 // data for the JVM. The memory may be created in standard or |
|
916 // shared memory. |
|
917 // |
|
918 void PerfMemory::create_memory_region(size_t size) { |
|
919 |
|
920 if (PerfDisableSharedMem) { |
|
921 // do not share the memory for the performance data. |
|
922 _start = create_standard_memory(size); |
|
923 } |
|
924 else { |
|
925 _start = create_shared_memory(size); |
|
926 if (_start == NULL) { |
|
927 |
|
928 // creation of the shared memory region failed, attempt |
|
929 // to create a contiguous, non-shared memory region instead. |
|
930 // |
|
931 if (PrintMiscellaneous && Verbose) { |
|
932 warning("Reverting to non-shared PerfMemory region.\n"); |
|
933 } |
|
934 PerfDisableSharedMem = true; |
|
935 _start = create_standard_memory(size); |
|
936 } |
|
937 } |
|
938 |
|
939 if (_start != NULL) _capacity = size; |
|
940 |
|
941 } |
|
942 |
|
943 // delete the PerfData memory region |
|
944 // |
|
945 // This method deletes the memory region used to store performance |
|
946 // data for the JVM. The memory region indicated by the <address, size> |
|
947 // tuple will be inaccessible after a call to this method. |
|
948 // |
|
949 void PerfMemory::delete_memory_region() { |
|
950 |
|
951 assert((start() != NULL && capacity() > 0), "verify proper state"); |
|
952 |
|
953 // If user specifies PerfDataSaveFile, it will save the performance data |
|
954 // to the specified file name no matter whether PerfDataSaveToFile is specified |
|
955 // or not. In other word, -XX:PerfDataSaveFile=.. overrides flag |
|
956 // -XX:+PerfDataSaveToFile. |
|
957 if (PerfDataSaveToFile || PerfDataSaveFile != NULL) { |
|
958 save_memory_to_file(start(), capacity()); |
|
959 } |
|
960 |
|
961 if (PerfDisableSharedMem) { |
|
962 delete_standard_memory(start(), capacity()); |
|
963 } |
|
964 else { |
|
965 delete_shared_memory(start(), capacity()); |
|
966 } |
|
967 } |
|
968 |
|
969 // attach to the PerfData memory region for another JVM |
|
970 // |
|
971 // This method returns an <address, size> tuple that points to |
|
972 // a memory buffer that is kept reasonably synchronized with |
|
973 // the PerfData memory region for the indicated JVM. This |
|
974 // buffer may be kept in synchronization via shared memory |
|
975 // or some other mechanism that keeps the buffer updated. |
|
976 // |
|
977 // If the JVM chooses not to support the attachability feature, |
|
978 // this method should throw an UnsupportedOperation exception. |
|
979 // |
|
980 // This implementation utilizes named shared memory to map |
|
981 // the indicated process's PerfData memory region into this JVMs |
|
982 // address space. |
|
983 // |
|
984 void PerfMemory::attach(const char* user, int vmid, PerfMemoryMode mode, char** addrp, size_t* sizep, TRAPS) { |
|
985 |
|
986 if (vmid == 0 || vmid == os::current_process_id()) { |
|
987 *addrp = start(); |
|
988 *sizep = capacity(); |
|
989 return; |
|
990 } |
|
991 |
|
992 mmap_attach_shared(user, vmid, mode, addrp, sizep, CHECK); |
|
993 } |
|
994 |
|
995 // detach from the PerfData memory region of another JVM |
|
996 // |
|
997 // This method detaches the PerfData memory region of another |
|
998 // JVM, specified as an <address, size> tuple of a buffer |
|
999 // in this process's address space. This method may perform |
|
1000 // arbitrary actions to accomplish the detachment. The memory |
|
1001 // region specified by <address, size> will be inaccessible after |
|
1002 // a call to this method. |
|
1003 // |
|
1004 // If the JVM chooses not to support the attachability feature, |
|
1005 // this method should throw an UnsupportedOperation exception. |
|
1006 // |
|
1007 // This implementation utilizes named shared memory to detach |
|
1008 // the indicated process's PerfData memory region from this |
|
1009 // process's address space. |
|
1010 // |
|
1011 void PerfMemory::detach(char* addr, size_t bytes, TRAPS) { |
|
1012 |
|
1013 assert(addr != 0, "address sanity check"); |
|
1014 assert(bytes > 0, "capacity sanity check"); |
|
1015 |
|
1016 if (PerfMemory::contains(addr) || PerfMemory::contains(addr + bytes - 1)) { |
|
1017 // prevent accidental detachment of this process's PerfMemory region |
|
1018 return; |
|
1019 } |
|
1020 |
|
1021 unmap_shared(addr, bytes); |
|
1022 } |
|
1023 |
|
1024 char* PerfMemory::backing_store_filename() { |
|
1025 return backing_store_file_name; |
|
1026 } |