1 | package File::Temp; |
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2 | |
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3 | =head1 NAME |
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4 | |
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5 | File::Temp - return name and handle of a temporary file safely |
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6 | |
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7 | =begin __INTERNALS |
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8 | |
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9 | =head1 PORTABILITY |
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10 | |
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11 | This module is designed to be portable across operating systems |
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12 | and it currently supports Unix, VMS, DOS, OS/2, Windows and |
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13 | Mac OS (Classic). When |
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14 | porting to a new OS there are generally three main issues |
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15 | that have to be solved: |
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16 | |
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17 | =over 4 |
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18 | |
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19 | =item * |
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20 | |
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21 | Can the OS unlink an open file? If it can not then the |
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22 | C<_can_unlink_opened_file> method should be modified. |
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23 | |
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24 | =item * |
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25 | |
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26 | Are the return values from C<stat> reliable? By default all the |
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27 | return values from C<stat> are compared when unlinking a temporary |
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28 | file using the filename and the handle. Operating systems other than |
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29 | unix do not always have valid entries in all fields. If C<unlink0> fails |
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30 | then the C<stat> comparison should be modified accordingly. |
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31 | |
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32 | =item * |
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33 | |
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34 | Security. Systems that can not support a test for the sticky bit |
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35 | on a directory can not use the MEDIUM and HIGH security tests. |
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36 | The C<_can_do_level> method should be modified accordingly. |
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37 | |
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38 | =back |
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39 | |
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40 | =end __INTERNALS |
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41 | |
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42 | =head1 SYNOPSIS |
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43 | |
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44 | use File::Temp qw/ tempfile tempdir /; |
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45 | |
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46 | $dir = tempdir( CLEANUP => 1 ); |
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47 | ($fh, $filename) = tempfile( DIR => $dir ); |
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48 | |
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49 | ($fh, $filename) = tempfile( $template, DIR => $dir); |
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50 | ($fh, $filename) = tempfile( $template, SUFFIX => '.dat'); |
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51 | |
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52 | $fh = tempfile(); |
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53 | |
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54 | MkTemp family: |
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55 | |
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56 | use File::Temp qw/ :mktemp /; |
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57 | |
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58 | ($fh, $file) = mkstemp( "tmpfileXXXXX" ); |
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59 | ($fh, $file) = mkstemps( "tmpfileXXXXXX", $suffix); |
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60 | |
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61 | $tmpdir = mkdtemp( $template ); |
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62 | |
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63 | $unopened_file = mktemp( $template ); |
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64 | |
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65 | POSIX functions: |
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66 | |
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67 | use File::Temp qw/ :POSIX /; |
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68 | |
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69 | $file = tmpnam(); |
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70 | $fh = tmpfile(); |
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71 | |
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72 | ($fh, $file) = tmpnam(); |
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73 | ($fh, $file) = tmpfile(); |
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74 | |
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75 | |
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76 | Compatibility functions: |
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77 | |
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78 | $unopened_file = File::Temp::tempnam( $dir, $pfx ); |
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79 | |
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80 | =begin later |
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81 | |
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82 | Objects (NOT YET IMPLEMENTED): |
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83 | |
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84 | require File::Temp; |
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85 | |
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86 | $fh = new File::Temp($template); |
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87 | $fname = $fh->filename; |
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88 | |
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89 | =end later |
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90 | |
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91 | =head1 DESCRIPTION |
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92 | |
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93 | C<File::Temp> can be used to create and open temporary files in a safe way. |
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94 | The tempfile() function can be used to return the name and the open |
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95 | filehandle of a temporary file. The tempdir() function can |
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96 | be used to create a temporary directory. |
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97 | |
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98 | The security aspect of temporary file creation is emphasized such that |
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99 | a filehandle and filename are returned together. This helps guarantee |
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100 | that a race condition can not occur where the temporary file is |
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101 | created by another process between checking for the existence of the |
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102 | file and its opening. Additional security levels are provided to |
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103 | check, for example, that the sticky bit is set on world writable |
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104 | directories. See L<"safe_level"> for more information. |
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105 | |
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106 | For compatibility with popular C library functions, Perl implementations of |
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107 | the mkstemp() family of functions are provided. These are, mkstemp(), |
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108 | mkstemps(), mkdtemp() and mktemp(). |
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109 | |
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110 | Additionally, implementations of the standard L<POSIX|POSIX> |
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111 | tmpnam() and tmpfile() functions are provided if required. |
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112 | |
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113 | Implementations of mktemp(), tmpnam(), and tempnam() are provided, |
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114 | but should be used with caution since they return only a filename |
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115 | that was valid when function was called, so cannot guarantee |
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116 | that the file will not exist by the time the caller opens the filename. |
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117 | |
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118 | =cut |
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119 | |
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120 | # 5.6.0 gives us S_IWOTH, S_IWGRP, our and auto-vivifying filehandls |
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121 | # People would like a version on 5.005 so give them what they want :-) |
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122 | use 5.005; |
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123 | use strict; |
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124 | use Carp; |
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125 | use File::Spec 0.8; |
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126 | use File::Path qw/ rmtree /; |
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127 | use Fcntl 1.03; |
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128 | use Errno; |
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129 | require VMS::Stdio if $^O eq 'VMS'; |
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130 | |
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131 | # Need the Symbol package if we are running older perl |
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132 | require Symbol if $] < 5.006; |
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133 | |
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134 | |
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135 | # use 'our' on v5.6.0 |
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136 | use vars qw($VERSION @EXPORT_OK %EXPORT_TAGS $DEBUG); |
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137 | |
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138 | $DEBUG = 0; |
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139 | |
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140 | # We are exporting functions |
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141 | |
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142 | use base qw/Exporter/; |
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143 | |
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144 | # Export list - to allow fine tuning of export table |
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145 | |
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146 | @EXPORT_OK = qw{ |
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147 | tempfile |
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148 | tempdir |
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149 | tmpnam |
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150 | tmpfile |
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151 | mktemp |
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152 | mkstemp |
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153 | mkstemps |
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154 | mkdtemp |
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155 | unlink0 |
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156 | }; |
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157 | |
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158 | # Groups of functions for export |
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159 | |
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160 | %EXPORT_TAGS = ( |
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161 | 'POSIX' => [qw/ tmpnam tmpfile /], |
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162 | 'mktemp' => [qw/ mktemp mkstemp mkstemps mkdtemp/], |
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163 | ); |
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164 | |
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165 | # add contents of these tags to @EXPORT |
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166 | Exporter::export_tags('POSIX','mktemp'); |
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167 | |
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168 | # Version number |
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169 | |
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170 | $VERSION = '0.13'; |
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171 | |
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172 | # This is a list of characters that can be used in random filenames |
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173 | |
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174 | my @CHARS = (qw/ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z |
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175 | a b c d e f g h i j k l m n o p q r s t u v w x y z |
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176 | 0 1 2 3 4 5 6 7 8 9 _ |
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177 | /); |
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178 | |
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179 | # Maximum number of tries to make a temp file before failing |
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180 | |
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181 | use constant MAX_TRIES => 10; |
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182 | |
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183 | # Minimum number of X characters that should be in a template |
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184 | use constant MINX => 4; |
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185 | |
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186 | # Default template when no template supplied |
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187 | |
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188 | use constant TEMPXXX => 'X' x 10; |
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189 | |
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190 | # Constants for the security level |
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191 | |
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192 | use constant STANDARD => 0; |
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193 | use constant MEDIUM => 1; |
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194 | use constant HIGH => 2; |
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195 | |
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196 | # OPENFLAGS. If we defined the flag to use with Sysopen here this gives |
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197 | # us an optimisation when many temporary files are requested |
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198 | |
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199 | my $OPENFLAGS = O_CREAT | O_EXCL | O_RDWR; |
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200 | |
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201 | unless ($^O eq 'MacOS') { |
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202 | for my $oflag (qw/ FOLLOW BINARY LARGEFILE EXLOCK NOINHERIT /) { |
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203 | my ($bit, $func) = (0, "Fcntl::O_" . $oflag); |
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204 | no strict 'refs'; |
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205 | $OPENFLAGS |= $bit if eval { |
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206 | # Make sure that redefined die handlers do not cause problems |
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207 | # eg CGI::Carp |
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208 | local $SIG{__DIE__} = sub {}; |
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209 | local $SIG{__WARN__} = sub {}; |
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210 | $bit = &$func(); |
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211 | 1; |
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212 | }; |
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213 | } |
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214 | } |
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215 | |
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216 | # On some systems the O_TEMPORARY flag can be used to tell the OS |
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217 | # to automatically remove the file when it is closed. This is fine |
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218 | # in most cases but not if tempfile is called with UNLINK=>0 and |
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219 | # the filename is requested -- in the case where the filename is to |
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220 | # be passed to another routine. This happens on windows. We overcome |
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221 | # this by using a second open flags variable |
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222 | |
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223 | my $OPENTEMPFLAGS = $OPENFLAGS; |
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224 | unless ($^O eq 'MacOS') { |
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225 | for my $oflag (qw/ TEMPORARY /) { |
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226 | my ($bit, $func) = (0, "Fcntl::O_" . $oflag); |
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227 | no strict 'refs'; |
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228 | $OPENTEMPFLAGS |= $bit if eval { |
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229 | # Make sure that redefined die handlers do not cause problems |
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230 | # eg CGI::Carp |
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231 | local $SIG{__DIE__} = sub {}; |
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232 | local $SIG{__WARN__} = sub {}; |
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233 | $bit = &$func(); |
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234 | 1; |
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235 | }; |
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236 | } |
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237 | } |
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238 | |
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239 | # INTERNAL ROUTINES - not to be used outside of package |
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240 | |
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241 | # Generic routine for getting a temporary filename |
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242 | # modelled on OpenBSD _gettemp() in mktemp.c |
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243 | |
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244 | # The template must contain X's that are to be replaced |
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245 | # with the random values |
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246 | |
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247 | # Arguments: |
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248 | |
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249 | # TEMPLATE - string containing the XXXXX's that is converted |
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250 | # to a random filename and opened if required |
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251 | |
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252 | # Optionally, a hash can also be supplied containing specific options |
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253 | # "open" => if true open the temp file, else just return the name |
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254 | # default is 0 |
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255 | # "mkdir"=> if true, we are creating a temp directory rather than tempfile |
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256 | # default is 0 |
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257 | # "suffixlen" => number of characters at end of PATH to be ignored. |
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258 | # default is 0. |
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259 | # "unlink_on_close" => indicates that, if possible, the OS should remove |
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260 | # the file as soon as it is closed. Usually indicates |
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261 | # use of the O_TEMPORARY flag to sysopen. |
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262 | # Usually irrelevant on unix |
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263 | |
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264 | # Optionally a reference to a scalar can be passed into the function |
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265 | # On error this will be used to store the reason for the error |
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266 | # "ErrStr" => \$errstr |
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267 | |
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268 | # "open" and "mkdir" can not both be true |
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269 | # "unlink_on_close" is not used when "mkdir" is true. |
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270 | |
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271 | # The default options are equivalent to mktemp(). |
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272 | |
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273 | # Returns: |
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274 | # filehandle - open file handle (if called with doopen=1, else undef) |
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275 | # temp name - name of the temp file or directory |
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276 | |
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277 | # For example: |
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278 | # ($fh, $name) = _gettemp($template, "open" => 1); |
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279 | |
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280 | # for the current version, failures are associated with |
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281 | # stored in an error string and returned to give the reason whilst debugging |
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282 | # This routine is not called by any external function |
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283 | sub _gettemp { |
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284 | |
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285 | croak 'Usage: ($fh, $name) = _gettemp($template, OPTIONS);' |
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286 | unless scalar(@_) >= 1; |
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287 | |
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288 | # the internal error string - expect it to be overridden |
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289 | # Need this in case the caller decides not to supply us a value |
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290 | # need an anonymous scalar |
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291 | my $tempErrStr; |
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292 | |
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293 | # Default options |
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294 | my %options = ( |
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295 | "open" => 0, |
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296 | "mkdir" => 0, |
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297 | "suffixlen" => 0, |
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298 | "unlink_on_close" => 0, |
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299 | "ErrStr" => \$tempErrStr, |
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300 | ); |
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301 | |
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302 | # Read the template |
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303 | my $template = shift; |
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304 | if (ref($template)) { |
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305 | # Use a warning here since we have not yet merged ErrStr |
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306 | carp "File::Temp::_gettemp: template must not be a reference"; |
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307 | return (); |
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308 | } |
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309 | |
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310 | # Check that the number of entries on stack are even |
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311 | if (scalar(@_) % 2 != 0) { |
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312 | # Use a warning here since we have not yet merged ErrStr |
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313 | carp "File::Temp::_gettemp: Must have even number of options"; |
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314 | return (); |
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315 | } |
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316 | |
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317 | # Read the options and merge with defaults |
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318 | %options = (%options, @_) if @_; |
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319 | |
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320 | # Make sure the error string is set to undef |
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321 | ${$options{ErrStr}} = undef; |
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322 | |
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323 | # Can not open the file and make a directory in a single call |
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324 | if ($options{"open"} && $options{"mkdir"}) { |
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325 | ${$options{ErrStr}} = "doopen and domkdir can not both be true\n"; |
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326 | return (); |
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327 | } |
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328 | |
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329 | # Find the start of the end of the Xs (position of last X) |
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330 | # Substr starts from 0 |
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331 | my $start = length($template) - 1 - $options{"suffixlen"}; |
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332 | |
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333 | # Check that we have at least MINX x X (eg 'XXXX") at the end of the string |
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334 | # (taking suffixlen into account). Any fewer is insecure. |
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335 | |
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336 | # Do it using substr - no reason to use a pattern match since |
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337 | # we know where we are looking and what we are looking for |
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338 | |
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339 | if (substr($template, $start - MINX + 1, MINX) ne 'X' x MINX) { |
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340 | ${$options{ErrStr}} = "The template must contain at least ". |
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341 | MINX . " 'X' characters\n"; |
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342 | return (); |
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343 | } |
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344 | |
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345 | # Replace all the X at the end of the substring with a |
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346 | # random character or just all the XX at the end of a full string. |
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347 | # Do it as an if, since the suffix adjusts which section to replace |
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348 | # and suffixlen=0 returns nothing if used in the substr directly |
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349 | # and generate a full path from the template |
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350 | |
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351 | my $path = _replace_XX($template, $options{"suffixlen"}); |
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352 | |
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353 | |
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354 | # Split the path into constituent parts - eventually we need to check |
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355 | # whether the directory exists |
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356 | # We need to know whether we are making a temp directory |
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357 | # or a tempfile |
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358 | |
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359 | my ($volume, $directories, $file); |
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360 | my $parent; # parent directory |
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361 | if ($options{"mkdir"}) { |
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362 | # There is no filename at the end |
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363 | ($volume, $directories, $file) = File::Spec->splitpath( $path, 1); |
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364 | |
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365 | # The parent is then $directories without the last directory |
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366 | # Split the directory and put it back together again |
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367 | my @dirs = File::Spec->splitdir($directories); |
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368 | |
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369 | # If @dirs only has one entry (i.e. the directory template) that means |
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370 | # we are in the current directory |
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371 | if ($#dirs == 0) { |
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372 | $parent = File::Spec->curdir; |
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373 | } else { |
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374 | |
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375 | if ($^O eq 'VMS') { # need volume to avoid relative dir spec |
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376 | $parent = File::Spec->catdir($volume, @dirs[0..$#dirs-1]); |
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377 | $parent = 'sys$disk:[]' if $parent eq ''; |
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378 | } else { |
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379 | |
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380 | # Put it back together without the last one |
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381 | $parent = File::Spec->catdir(@dirs[0..$#dirs-1]); |
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382 | |
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383 | # ...and attach the volume (no filename) |
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384 | $parent = File::Spec->catpath($volume, $parent, ''); |
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385 | } |
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386 | |
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387 | } |
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388 | |
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389 | } else { |
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390 | |
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391 | # Get rid of the last filename (use File::Basename for this?) |
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392 | ($volume, $directories, $file) = File::Spec->splitpath( $path ); |
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393 | |
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394 | # Join up without the file part |
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395 | $parent = File::Spec->catpath($volume,$directories,''); |
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396 | |
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397 | # If $parent is empty replace with curdir |
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398 | $parent = File::Spec->curdir |
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399 | unless $directories ne ''; |
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400 | |
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401 | } |
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402 | |
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403 | # Check that the parent directories exist |
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404 | # Do this even for the case where we are simply returning a name |
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405 | # not a file -- no point returning a name that includes a directory |
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406 | # that does not exist or is not writable |
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407 | |
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408 | unless (-d $parent) { |
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409 | ${$options{ErrStr}} = "Parent directory ($parent) is not a directory"; |
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410 | return (); |
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411 | } |
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412 | unless (-w _) { |
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413 | ${$options{ErrStr}} = "Parent directory ($parent) is not writable\n"; |
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414 | return (); |
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415 | } |
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416 | |
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417 | |
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418 | # Check the stickiness of the directory and chown giveaway if required |
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419 | # If the directory is world writable the sticky bit |
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420 | # must be set |
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421 | |
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422 | if (File::Temp->safe_level == MEDIUM) { |
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423 | my $safeerr; |
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424 | unless (_is_safe($parent,\$safeerr)) { |
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425 | ${$options{ErrStr}} = "Parent directory ($parent) is not safe ($safeerr)"; |
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426 | return (); |
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427 | } |
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428 | } elsif (File::Temp->safe_level == HIGH) { |
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429 | my $safeerr; |
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430 | unless (_is_verysafe($parent, \$safeerr)) { |
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431 | ${$options{ErrStr}} = "Parent directory ($parent) is not safe ($safeerr)"; |
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432 | return (); |
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433 | } |
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434 | } |
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435 | |
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436 | |
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437 | # Now try MAX_TRIES time to open the file |
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438 | for (my $i = 0; $i < MAX_TRIES; $i++) { |
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439 | |
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440 | # Try to open the file if requested |
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441 | if ($options{"open"}) { |
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442 | my $fh; |
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443 | |
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444 | # If we are running before perl5.6.0 we can not auto-vivify |
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445 | if ($] < 5.006) { |
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446 | $fh = &Symbol::gensym; |
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447 | } |
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448 | |
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449 | # Try to make sure this will be marked close-on-exec |
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450 | # XXX: Win32 doesn't respect this, nor the proper fcntl, |
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451 | # but may have O_NOINHERIT. This may or may not be in Fcntl. |
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452 | local $^F = 2; |
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453 | |
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454 | # Store callers umask |
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455 | my $umask = umask(); |
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456 | |
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457 | # Set a known umask |
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458 | umask(066); |
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459 | |
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460 | # Attempt to open the file |
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461 | my $open_success = undef; |
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462 | if ( $^O eq 'VMS' and $options{"unlink_on_close"} ) { |
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463 | # make it auto delete on close by setting FAB$V_DLT bit |
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464 | $fh = VMS::Stdio::vmssysopen($path, $OPENFLAGS, 0600, 'fop=dlt'); |
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465 | $open_success = $fh; |
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466 | } else { |
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467 | my $flags = ( $options{"unlink_on_close"} ? |
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468 | $OPENTEMPFLAGS : |
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469 | $OPENFLAGS ); |
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470 | $open_success = sysopen($fh, $path, $flags, 0600); |
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471 | } |
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472 | if ( $open_success ) { |
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473 | |
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474 | # Reset umask |
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475 | umask($umask) if defined $umask; |
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476 | |
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477 | # Opened successfully - return file handle and name |
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478 | return ($fh, $path); |
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479 | |
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480 | } else { |
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481 | # Reset umask |
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482 | umask($umask) if defined $umask; |
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483 | |
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484 | # Error opening file - abort with error |
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485 | # if the reason was anything but EEXIST |
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486 | unless ($!{EEXIST}) { |
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487 | ${$options{ErrStr}} = "Could not create temp file $path: $!"; |
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488 | return (); |
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489 | } |
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490 | |
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491 | # Loop round for another try |
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492 | |
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493 | } |
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494 | } elsif ($options{"mkdir"}) { |
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495 | |
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496 | # Store callers umask |
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497 | my $umask = umask(); |
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498 | |
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499 | # Set a known umask |
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500 | umask(066); |
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501 | |
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502 | # Open the temp directory |
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503 | if (mkdir( $path, 0700)) { |
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504 | # created okay |
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505 | # Reset umask |
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506 | umask($umask) if defined $umask; |
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507 | |
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508 | return undef, $path; |
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509 | } else { |
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510 | |
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511 | # Reset umask |
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512 | umask($umask) if defined $umask; |
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513 | |
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514 | # Abort with error if the reason for failure was anything |
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515 | # except EEXIST |
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516 | unless ($!{EEXIST}) { |
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517 | ${$options{ErrStr}} = "Could not create directory $path: $!"; |
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518 | return (); |
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519 | } |
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520 | |
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521 | # Loop round for another try |
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522 | |
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523 | } |
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524 | |
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525 | } else { |
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526 | |
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527 | # Return true if the file can not be found |
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528 | # Directory has been checked previously |
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529 | |
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530 | return (undef, $path) unless -e $path; |
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531 | |
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532 | # Try again until MAX_TRIES |
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533 | |
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534 | } |
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535 | |
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536 | # Did not successfully open the tempfile/dir |
---|
537 | # so try again with a different set of random letters |
---|
538 | # No point in trying to increment unless we have only |
---|
539 | # 1 X say and the randomness could come up with the same |
---|
540 | # file MAX_TRIES in a row. |
---|
541 | |
---|
542 | # Store current attempt - in principal this implies that the |
---|
543 | # 3rd time around the open attempt that the first temp file |
---|
544 | # name could be generated again. Probably should store each |
---|
545 | # attempt and make sure that none are repeated |
---|
546 | |
---|
547 | my $original = $path; |
---|
548 | my $counter = 0; # Stop infinite loop |
---|
549 | my $MAX_GUESS = 50; |
---|
550 | |
---|
551 | do { |
---|
552 | |
---|
553 | # Generate new name from original template |
---|
554 | $path = _replace_XX($template, $options{"suffixlen"}); |
---|
555 | |
---|
556 | $counter++; |
---|
557 | |
---|
558 | } until ($path ne $original || $counter > $MAX_GUESS); |
---|
559 | |
---|
560 | # Check for out of control looping |
---|
561 | if ($counter > $MAX_GUESS) { |
---|
562 | ${$options{ErrStr}} = "Tried to get a new temp name different to the previous value $MAX_GUESS times.\nSomething wrong with template?? ($template)"; |
---|
563 | return (); |
---|
564 | } |
---|
565 | |
---|
566 | } |
---|
567 | |
---|
568 | # If we get here, we have run out of tries |
---|
569 | ${ $options{ErrStr} } = "Have exceeded the maximum number of attempts (" |
---|
570 | . MAX_TRIES . ") to open temp file/dir"; |
---|
571 | |
---|
572 | return (); |
---|
573 | |
---|
574 | } |
---|
575 | |
---|
576 | # Internal routine to return a random character from the |
---|
577 | # character list. Does not do an srand() since rand() |
---|
578 | # will do one automatically |
---|
579 | |
---|
580 | # No arguments. Return value is the random character |
---|
581 | |
---|
582 | # No longer called since _replace_XX runs a few percent faster if |
---|
583 | # I inline the code. This is important if we are creating thousands of |
---|
584 | # temporary files. |
---|
585 | |
---|
586 | sub _randchar { |
---|
587 | |
---|
588 | $CHARS[ int( rand( $#CHARS ) ) ]; |
---|
589 | |
---|
590 | } |
---|
591 | |
---|
592 | # Internal routine to replace the XXXX... with random characters |
---|
593 | # This has to be done by _gettemp() every time it fails to |
---|
594 | # open a temp file/dir |
---|
595 | |
---|
596 | # Arguments: $template (the template with XXX), |
---|
597 | # $ignore (number of characters at end to ignore) |
---|
598 | |
---|
599 | # Returns: modified template |
---|
600 | |
---|
601 | sub _replace_XX { |
---|
602 | |
---|
603 | croak 'Usage: _replace_XX($template, $ignore)' |
---|
604 | unless scalar(@_) == 2; |
---|
605 | |
---|
606 | my ($path, $ignore) = @_; |
---|
607 | |
---|
608 | # Do it as an if, since the suffix adjusts which section to replace |
---|
609 | # and suffixlen=0 returns nothing if used in the substr directly |
---|
610 | # Alternatively, could simply set $ignore to length($path)-1 |
---|
611 | # Don't want to always use substr when not required though. |
---|
612 | |
---|
613 | if ($ignore) { |
---|
614 | substr($path, 0, - $ignore) =~ s/X(?=X*\z)/$CHARS[ int( rand( $#CHARS ) ) ]/ge; |
---|
615 | } else { |
---|
616 | $path =~ s/X(?=X*\z)/$CHARS[ int( rand( $#CHARS ) ) ]/ge; |
---|
617 | } |
---|
618 | |
---|
619 | return $path; |
---|
620 | } |
---|
621 | |
---|
622 | # internal routine to check to see if the directory is safe |
---|
623 | # First checks to see if the directory is not owned by the |
---|
624 | # current user or root. Then checks to see if anyone else |
---|
625 | # can write to the directory and if so, checks to see if |
---|
626 | # it has the sticky bit set |
---|
627 | |
---|
628 | # Will not work on systems that do not support sticky bit |
---|
629 | |
---|
630 | #Args: directory path to check |
---|
631 | # Optionally: reference to scalar to contain error message |
---|
632 | # Returns true if the path is safe and false otherwise. |
---|
633 | # Returns undef if can not even run stat() on the path |
---|
634 | |
---|
635 | # This routine based on version written by Tom Christiansen |
---|
636 | |
---|
637 | # Presumably, by the time we actually attempt to create the |
---|
638 | # file or directory in this directory, it may not be safe |
---|
639 | # anymore... Have to run _is_safe directly after the open. |
---|
640 | |
---|
641 | sub _is_safe { |
---|
642 | |
---|
643 | my $path = shift; |
---|
644 | my $err_ref = shift; |
---|
645 | |
---|
646 | # Stat path |
---|
647 | my @info = stat($path); |
---|
648 | unless (scalar(@info)) { |
---|
649 | $$err_ref = "stat(path) returned no values"; |
---|
650 | return 0; |
---|
651 | }; |
---|
652 | return 1 if $^O eq 'VMS'; # owner delete control at file level |
---|
653 | |
---|
654 | # Check to see whether owner is neither superuser (or a system uid) nor me |
---|
655 | # Use the real uid from the $< variable |
---|
656 | # UID is in [4] |
---|
657 | if ($info[4] > File::Temp->top_system_uid() && $info[4] != $<) { |
---|
658 | |
---|
659 | Carp::cluck(sprintf "uid=$info[4] topuid=%s \$<=$< path='$path'", |
---|
660 | File::Temp->top_system_uid()); |
---|
661 | |
---|
662 | $$err_ref = "Directory owned neither by root nor the current user" |
---|
663 | if ref($err_ref); |
---|
664 | return 0; |
---|
665 | } |
---|
666 | |
---|
667 | # check whether group or other can write file |
---|
668 | # use 066 to detect either reading or writing |
---|
669 | # use 022 to check writability |
---|
670 | # Do it with S_IWOTH and S_IWGRP for portability (maybe) |
---|
671 | # mode is in info[2] |
---|
672 | if (($info[2] & &Fcntl::S_IWGRP) || # Is group writable? |
---|
673 | ($info[2] & &Fcntl::S_IWOTH) ) { # Is world writable? |
---|
674 | # Must be a directory |
---|
675 | unless (-d _) { |
---|
676 | $$err_ref = "Path ($path) is not a directory" |
---|
677 | if ref($err_ref); |
---|
678 | return 0; |
---|
679 | } |
---|
680 | # Must have sticky bit set |
---|
681 | unless (-k _) { |
---|
682 | $$err_ref = "Sticky bit not set on $path when dir is group|world writable" |
---|
683 | if ref($err_ref); |
---|
684 | return 0; |
---|
685 | } |
---|
686 | } |
---|
687 | |
---|
688 | return 1; |
---|
689 | } |
---|
690 | |
---|
691 | # Internal routine to check whether a directory is safe |
---|
692 | # for temp files. Safer than _is_safe since it checks for |
---|
693 | # the possibility of chown giveaway and if that is a possibility |
---|
694 | # checks each directory in the path to see if it is safe (with _is_safe) |
---|
695 | |
---|
696 | # If _PC_CHOWN_RESTRICTED is not set, does the full test of each |
---|
697 | # directory anyway. |
---|
698 | |
---|
699 | # Takes optional second arg as scalar ref to error reason |
---|
700 | |
---|
701 | sub _is_verysafe { |
---|
702 | |
---|
703 | # Need POSIX - but only want to bother if really necessary due to overhead |
---|
704 | require POSIX; |
---|
705 | |
---|
706 | my $path = shift; |
---|
707 | print "_is_verysafe testing $path\n" if $DEBUG; |
---|
708 | return 1 if $^O eq 'VMS'; # owner delete control at file level |
---|
709 | |
---|
710 | my $err_ref = shift; |
---|
711 | |
---|
712 | # Should Get the value of _PC_CHOWN_RESTRICTED if it is defined |
---|
713 | # and If it is not there do the extensive test |
---|
714 | my $chown_restricted; |
---|
715 | $chown_restricted = &POSIX::_PC_CHOWN_RESTRICTED() |
---|
716 | if eval { &POSIX::_PC_CHOWN_RESTRICTED(); 1}; |
---|
717 | |
---|
718 | # If chown_resticted is set to some value we should test it |
---|
719 | if (defined $chown_restricted) { |
---|
720 | |
---|
721 | # Return if the current directory is safe |
---|
722 | return _is_safe($path,$err_ref) if POSIX::sysconf( $chown_restricted ); |
---|
723 | |
---|
724 | } |
---|
725 | |
---|
726 | # To reach this point either, the _PC_CHOWN_RESTRICTED symbol |
---|
727 | # was not avialable or the symbol was there but chown giveaway |
---|
728 | # is allowed. Either way, we now have to test the entire tree for |
---|
729 | # safety. |
---|
730 | |
---|
731 | # Convert path to an absolute directory if required |
---|
732 | unless (File::Spec->file_name_is_absolute($path)) { |
---|
733 | $path = File::Spec->rel2abs($path); |
---|
734 | } |
---|
735 | |
---|
736 | # Split directory into components - assume no file |
---|
737 | my ($volume, $directories, undef) = File::Spec->splitpath( $path, 1); |
---|
738 | |
---|
739 | # Slightly less efficient than having a function in File::Spec |
---|
740 | # to chop off the end of a directory or even a function that |
---|
741 | # can handle ../ in a directory tree |
---|
742 | # Sometimes splitdir() returns a blank at the end |
---|
743 | # so we will probably check the bottom directory twice in some cases |
---|
744 | my @dirs = File::Spec->splitdir($directories); |
---|
745 | |
---|
746 | # Concatenate one less directory each time around |
---|
747 | foreach my $pos (0.. $#dirs) { |
---|
748 | # Get a directory name |
---|
749 | my $dir = File::Spec->catpath($volume, |
---|
750 | File::Spec->catdir(@dirs[0.. $#dirs - $pos]), |
---|
751 | '' |
---|
752 | ); |
---|
753 | |
---|
754 | print "TESTING DIR $dir\n" if $DEBUG; |
---|
755 | |
---|
756 | # Check the directory |
---|
757 | return 0 unless _is_safe($dir,$err_ref); |
---|
758 | |
---|
759 | } |
---|
760 | |
---|
761 | return 1; |
---|
762 | } |
---|
763 | |
---|
764 | |
---|
765 | |
---|
766 | # internal routine to determine whether unlink works on this |
---|
767 | # platform for files that are currently open. |
---|
768 | # Returns true if we can, false otherwise. |
---|
769 | |
---|
770 | # Currently WinNT, OS/2 and VMS can not unlink an opened file |
---|
771 | # On VMS this is because the O_EXCL flag is used to open the |
---|
772 | # temporary file. Currently I do not know enough about the issues |
---|
773 | # on VMS to decide whether O_EXCL is a requirement. |
---|
774 | |
---|
775 | sub _can_unlink_opened_file { |
---|
776 | |
---|
777 | if ($^O eq 'MSWin32' || $^O eq 'os2' || $^O eq 'VMS' || $^O eq 'dos' || $^O eq 'MacOS') { |
---|
778 | return 0; |
---|
779 | } else { |
---|
780 | return 1; |
---|
781 | } |
---|
782 | |
---|
783 | } |
---|
784 | |
---|
785 | # internal routine to decide which security levels are allowed |
---|
786 | # see safe_level() for more information on this |
---|
787 | |
---|
788 | # Controls whether the supplied security level is allowed |
---|
789 | |
---|
790 | # $cando = _can_do_level( $level ) |
---|
791 | |
---|
792 | sub _can_do_level { |
---|
793 | |
---|
794 | # Get security level |
---|
795 | my $level = shift; |
---|
796 | |
---|
797 | # Always have to be able to do STANDARD |
---|
798 | return 1 if $level == STANDARD; |
---|
799 | |
---|
800 | # Currently, the systems that can do HIGH or MEDIUM are identical |
---|
801 | if ( $^O eq 'MSWin32' || $^O eq 'os2' || $^O eq 'cygwin' || $^O eq 'dos' || $^O eq 'MacOS') { |
---|
802 | return 0; |
---|
803 | } else { |
---|
804 | return 1; |
---|
805 | } |
---|
806 | |
---|
807 | } |
---|
808 | |
---|
809 | # This routine sets up a deferred unlinking of a specified |
---|
810 | # filename and filehandle. It is used in the following cases: |
---|
811 | # - Called by unlink0 if an opened file can not be unlinked |
---|
812 | # - Called by tempfile() if files are to be removed on shutdown |
---|
813 | # - Called by tempdir() if directories are to be removed on shutdown |
---|
814 | |
---|
815 | # Arguments: |
---|
816 | # _deferred_unlink( $fh, $fname, $isdir ); |
---|
817 | # |
---|
818 | # - filehandle (so that it can be expclicitly closed if open |
---|
819 | # - filename (the thing we want to remove) |
---|
820 | # - isdir (flag to indicate that we are being given a directory) |
---|
821 | # [and hence no filehandle] |
---|
822 | |
---|
823 | # Status is not referred to since all the magic is done with an END block |
---|
824 | |
---|
825 | { |
---|
826 | # Will set up two lexical variables to contain all the files to be |
---|
827 | # removed. One array for files, another for directories |
---|
828 | # They will only exist in this block |
---|
829 | # This means we only have to set up a single END block to remove all files |
---|
830 | # @files_to_unlink contains an array ref with the filehandle and filename |
---|
831 | my (@files_to_unlink, @dirs_to_unlink); |
---|
832 | |
---|
833 | # Set up an end block to use these arrays |
---|
834 | END { |
---|
835 | # Files |
---|
836 | foreach my $file (@files_to_unlink) { |
---|
837 | # close the filehandle without checking its state |
---|
838 | # in order to make real sure that this is closed |
---|
839 | # if its already closed then I dont care about the answer |
---|
840 | # probably a better way to do this |
---|
841 | close($file->[0]); # file handle is [0] |
---|
842 | |
---|
843 | if (-f $file->[1]) { # file name is [1] |
---|
844 | unlink $file->[1] or warn "Error removing ".$file->[1]; |
---|
845 | } |
---|
846 | } |
---|
847 | # Dirs |
---|
848 | foreach my $dir (@dirs_to_unlink) { |
---|
849 | if (-d $dir) { |
---|
850 | rmtree($dir, $DEBUG, 1); |
---|
851 | } |
---|
852 | } |
---|
853 | |
---|
854 | } |
---|
855 | |
---|
856 | # This is the sub called to register a file for deferred unlinking |
---|
857 | # This could simply store the input parameters and defer everything |
---|
858 | # until the END block. For now we do a bit of checking at this |
---|
859 | # point in order to make sure that (1) we have a file/dir to delete |
---|
860 | # and (2) we have been called with the correct arguments. |
---|
861 | sub _deferred_unlink { |
---|
862 | |
---|
863 | croak 'Usage: _deferred_unlink($fh, $fname, $isdir)' |
---|
864 | unless scalar(@_) == 3; |
---|
865 | |
---|
866 | my ($fh, $fname, $isdir) = @_; |
---|
867 | |
---|
868 | warn "Setting up deferred removal of $fname\n" |
---|
869 | if $DEBUG; |
---|
870 | |
---|
871 | # If we have a directory, check that it is a directory |
---|
872 | if ($isdir) { |
---|
873 | |
---|
874 | if (-d $fname) { |
---|
875 | |
---|
876 | # Directory exists so store it |
---|
877 | # first on VMS turn []foo into [.foo] for rmtree |
---|
878 | $fname = VMS::Filespec::vmspath($fname) if $^O eq 'VMS'; |
---|
879 | push (@dirs_to_unlink, $fname); |
---|
880 | |
---|
881 | } else { |
---|
882 | carp "Request to remove directory $fname could not be completed since it does not exist!\n" if $^W; |
---|
883 | } |
---|
884 | |
---|
885 | } else { |
---|
886 | |
---|
887 | if (-f $fname) { |
---|
888 | |
---|
889 | # file exists so store handle and name for later removal |
---|
890 | push(@files_to_unlink, [$fh, $fname]); |
---|
891 | |
---|
892 | } else { |
---|
893 | carp "Request to remove file $fname could not be completed since it is not there!\n" if $^W; |
---|
894 | } |
---|
895 | |
---|
896 | } |
---|
897 | |
---|
898 | } |
---|
899 | |
---|
900 | |
---|
901 | } |
---|
902 | |
---|
903 | =head1 FUNCTIONS |
---|
904 | |
---|
905 | This section describes the recommended interface for generating |
---|
906 | temporary files and directories. |
---|
907 | |
---|
908 | =over 4 |
---|
909 | |
---|
910 | =item B<tempfile> |
---|
911 | |
---|
912 | This is the basic function to generate temporary files. |
---|
913 | The behaviour of the file can be changed using various options: |
---|
914 | |
---|
915 | ($fh, $filename) = tempfile(); |
---|
916 | |
---|
917 | Create a temporary file in the directory specified for temporary |
---|
918 | files, as specified by the tmpdir() function in L<File::Spec>. |
---|
919 | |
---|
920 | ($fh, $filename) = tempfile($template); |
---|
921 | |
---|
922 | Create a temporary file in the current directory using the supplied |
---|
923 | template. Trailing `X' characters are replaced with random letters to |
---|
924 | generate the filename. At least four `X' characters must be present |
---|
925 | in the template. |
---|
926 | |
---|
927 | ($fh, $filename) = tempfile($template, SUFFIX => $suffix) |
---|
928 | |
---|
929 | Same as previously, except that a suffix is added to the template |
---|
930 | after the `X' translation. Useful for ensuring that a temporary |
---|
931 | filename has a particular extension when needed by other applications. |
---|
932 | But see the WARNING at the end. |
---|
933 | |
---|
934 | ($fh, $filename) = tempfile($template, DIR => $dir); |
---|
935 | |
---|
936 | Translates the template as before except that a directory name |
---|
937 | is specified. |
---|
938 | |
---|
939 | ($fh, $filename) = tempfile($template, UNLINK => 1); |
---|
940 | |
---|
941 | Return the filename and filehandle as before except that the file is |
---|
942 | automatically removed when the program exits. Default is for the file |
---|
943 | to be removed if a file handle is requested and to be kept if the |
---|
944 | filename is requested. In a scalar context (where no filename is |
---|
945 | returned) the file is always deleted either on exit or when it is closed. |
---|
946 | |
---|
947 | If the template is not specified, a template is always |
---|
948 | automatically generated. This temporary file is placed in tmpdir() |
---|
949 | (L<File::Spec>) unless a directory is specified explicitly with the |
---|
950 | DIR option. |
---|
951 | |
---|
952 | $fh = tempfile( $template, DIR => $dir ); |
---|
953 | |
---|
954 | If called in scalar context, only the filehandle is returned |
---|
955 | and the file will automatically be deleted when closed (see |
---|
956 | the description of tmpfile() elsewhere in this document). |
---|
957 | This is the preferred mode of operation, as if you only |
---|
958 | have a filehandle, you can never create a race condition |
---|
959 | by fumbling with the filename. On systems that can not unlink |
---|
960 | an open file or can not mark a file as temporary when it is opened |
---|
961 | (for example, Windows NT uses the C<O_TEMPORARY> flag)) |
---|
962 | the file is marked for deletion when the program ends (equivalent |
---|
963 | to setting UNLINK to 1). The C<UNLINK> flag is ignored if present. |
---|
964 | |
---|
965 | (undef, $filename) = tempfile($template, OPEN => 0); |
---|
966 | |
---|
967 | This will return the filename based on the template but |
---|
968 | will not open this file. Cannot be used in conjunction with |
---|
969 | UNLINK set to true. Default is to always open the file |
---|
970 | to protect from possible race conditions. A warning is issued |
---|
971 | if warnings are turned on. Consider using the tmpnam() |
---|
972 | and mktemp() functions described elsewhere in this document |
---|
973 | if opening the file is not required. |
---|
974 | |
---|
975 | Options can be combined as required. |
---|
976 | |
---|
977 | =cut |
---|
978 | |
---|
979 | sub tempfile { |
---|
980 | |
---|
981 | # Can not check for argument count since we can have any |
---|
982 | # number of args |
---|
983 | |
---|
984 | # Default options |
---|
985 | my %options = ( |
---|
986 | "DIR" => undef, # Directory prefix |
---|
987 | "SUFFIX" => '', # Template suffix |
---|
988 | "UNLINK" => 0, # Do not unlink file on exit |
---|
989 | "OPEN" => 1, # Open file |
---|
990 | ); |
---|
991 | |
---|
992 | # Check to see whether we have an odd or even number of arguments |
---|
993 | my $template = (scalar(@_) % 2 == 1 ? shift(@_) : undef); |
---|
994 | |
---|
995 | # Read the options and merge with defaults |
---|
996 | %options = (%options, @_) if @_; |
---|
997 | |
---|
998 | # First decision is whether or not to open the file |
---|
999 | if (! $options{"OPEN"}) { |
---|
1000 | |
---|
1001 | warn "tempfile(): temporary filename requested but not opened.\nPossibly unsafe, consider using tempfile() with OPEN set to true\n" |
---|
1002 | if $^W; |
---|
1003 | |
---|
1004 | } |
---|
1005 | |
---|
1006 | if ($options{"DIR"} and $^O eq 'VMS') { |
---|
1007 | |
---|
1008 | # on VMS turn []foo into [.foo] for concatenation |
---|
1009 | $options{"DIR"} = VMS::Filespec::vmspath($options{"DIR"}); |
---|
1010 | } |
---|
1011 | |
---|
1012 | # Construct the template |
---|
1013 | |
---|
1014 | # Have a choice of trying to work around the mkstemp/mktemp/tmpnam etc |
---|
1015 | # functions or simply constructing a template and using _gettemp() |
---|
1016 | # explicitly. Go for the latter |
---|
1017 | |
---|
1018 | # First generate a template if not defined and prefix the directory |
---|
1019 | # If no template must prefix the temp directory |
---|
1020 | if (defined $template) { |
---|
1021 | if ($options{"DIR"}) { |
---|
1022 | |
---|
1023 | $template = File::Spec->catfile($options{"DIR"}, $template); |
---|
1024 | |
---|
1025 | } |
---|
1026 | |
---|
1027 | } else { |
---|
1028 | |
---|
1029 | if ($options{"DIR"}) { |
---|
1030 | |
---|
1031 | $template = File::Spec->catfile($options{"DIR"}, TEMPXXX); |
---|
1032 | |
---|
1033 | } else { |
---|
1034 | |
---|
1035 | $template = File::Spec->catfile(File::Spec->tmpdir, TEMPXXX); |
---|
1036 | |
---|
1037 | } |
---|
1038 | |
---|
1039 | } |
---|
1040 | |
---|
1041 | # Now add a suffix |
---|
1042 | $template .= $options{"SUFFIX"}; |
---|
1043 | |
---|
1044 | # Determine whether we should tell _gettemp to unlink the file |
---|
1045 | # On unix this is irrelevant and can be worked out after the file is |
---|
1046 | # opened (simply by unlinking the open filehandle). On Windows or VMS |
---|
1047 | # we have to indicate temporary-ness when we open the file. In general |
---|
1048 | # we only want a true temporary file if we are returning just the |
---|
1049 | # filehandle - if the user wants the filename they probably do not |
---|
1050 | # want the file to disappear as soon as they close it. |
---|
1051 | # For this reason, tie unlink_on_close to the return context regardless |
---|
1052 | # of OS. |
---|
1053 | my $unlink_on_close = ( wantarray ? 0 : 1); |
---|
1054 | |
---|
1055 | # Create the file |
---|
1056 | my ($fh, $path, $errstr); |
---|
1057 | croak "Error in tempfile() using $template: $errstr" |
---|
1058 | unless (($fh, $path) = _gettemp($template, |
---|
1059 | "open" => $options{'OPEN'}, |
---|
1060 | "mkdir"=> 0 , |
---|
1061 | "unlink_on_close" => $unlink_on_close, |
---|
1062 | "suffixlen" => length($options{'SUFFIX'}), |
---|
1063 | "ErrStr" => \$errstr, |
---|
1064 | ) ); |
---|
1065 | |
---|
1066 | # Set up an exit handler that can do whatever is right for the |
---|
1067 | # system. This removes files at exit when requested explicitly or when |
---|
1068 | # system is asked to unlink_on_close but is unable to do so because |
---|
1069 | # of OS limitations. |
---|
1070 | # The latter should be achieved by using a tied filehandle. |
---|
1071 | # Do not check return status since this is all done with END blocks. |
---|
1072 | _deferred_unlink($fh, $path, 0) if $options{"UNLINK"}; |
---|
1073 | |
---|
1074 | # Return |
---|
1075 | if (wantarray()) { |
---|
1076 | |
---|
1077 | if ($options{'OPEN'}) { |
---|
1078 | return ($fh, $path); |
---|
1079 | } else { |
---|
1080 | return (undef, $path); |
---|
1081 | } |
---|
1082 | |
---|
1083 | } else { |
---|
1084 | |
---|
1085 | # Unlink the file. It is up to unlink0 to decide what to do with |
---|
1086 | # this (whether to unlink now or to defer until later) |
---|
1087 | unlink0($fh, $path) or croak "Error unlinking file $path using unlink0"; |
---|
1088 | |
---|
1089 | # Return just the filehandle. |
---|
1090 | return $fh; |
---|
1091 | } |
---|
1092 | |
---|
1093 | |
---|
1094 | } |
---|
1095 | |
---|
1096 | =item B<tempdir> |
---|
1097 | |
---|
1098 | This is the recommended interface for creation of temporary directories. |
---|
1099 | The behaviour of the function depends on the arguments: |
---|
1100 | |
---|
1101 | $tempdir = tempdir(); |
---|
1102 | |
---|
1103 | Create a directory in tmpdir() (see L<File::Spec|File::Spec>). |
---|
1104 | |
---|
1105 | $tempdir = tempdir( $template ); |
---|
1106 | |
---|
1107 | Create a directory from the supplied template. This template is |
---|
1108 | similar to that described for tempfile(). `X' characters at the end |
---|
1109 | of the template are replaced with random letters to construct the |
---|
1110 | directory name. At least four `X' characters must be in the template. |
---|
1111 | |
---|
1112 | $tempdir = tempdir ( DIR => $dir ); |
---|
1113 | |
---|
1114 | Specifies the directory to use for the temporary directory. |
---|
1115 | The temporary directory name is derived from an internal template. |
---|
1116 | |
---|
1117 | $tempdir = tempdir ( $template, DIR => $dir ); |
---|
1118 | |
---|
1119 | Prepend the supplied directory name to the template. The template |
---|
1120 | should not include parent directory specifications itself. Any parent |
---|
1121 | directory specifications are removed from the template before |
---|
1122 | prepending the supplied directory. |
---|
1123 | |
---|
1124 | $tempdir = tempdir ( $template, TMPDIR => 1 ); |
---|
1125 | |
---|
1126 | Using the supplied template, create the temporary directory in |
---|
1127 | a standard location for temporary files. Equivalent to doing |
---|
1128 | |
---|
1129 | $tempdir = tempdir ( $template, DIR => File::Spec->tmpdir); |
---|
1130 | |
---|
1131 | but shorter. Parent directory specifications are stripped from the |
---|
1132 | template itself. The C<TMPDIR> option is ignored if C<DIR> is set |
---|
1133 | explicitly. Additionally, C<TMPDIR> is implied if neither a template |
---|
1134 | nor a directory are supplied. |
---|
1135 | |
---|
1136 | $tempdir = tempdir( $template, CLEANUP => 1); |
---|
1137 | |
---|
1138 | Create a temporary directory using the supplied template, but |
---|
1139 | attempt to remove it (and all files inside it) when the program |
---|
1140 | exits. Note that an attempt will be made to remove all files from |
---|
1141 | the directory even if they were not created by this module (otherwise |
---|
1142 | why ask to clean it up?). The directory removal is made with |
---|
1143 | the rmtree() function from the L<File::Path|File::Path> module. |
---|
1144 | Of course, if the template is not specified, the temporary directory |
---|
1145 | will be created in tmpdir() and will also be removed at program exit. |
---|
1146 | |
---|
1147 | =cut |
---|
1148 | |
---|
1149 | # ' |
---|
1150 | |
---|
1151 | sub tempdir { |
---|
1152 | |
---|
1153 | # Can not check for argument count since we can have any |
---|
1154 | # number of args |
---|
1155 | |
---|
1156 | # Default options |
---|
1157 | my %options = ( |
---|
1158 | "CLEANUP" => 0, # Remove directory on exit |
---|
1159 | "DIR" => '', # Root directory |
---|
1160 | "TMPDIR" => 0, # Use tempdir with template |
---|
1161 | ); |
---|
1162 | |
---|
1163 | # Check to see whether we have an odd or even number of arguments |
---|
1164 | my $template = (scalar(@_) % 2 == 1 ? shift(@_) : undef ); |
---|
1165 | |
---|
1166 | # Read the options and merge with defaults |
---|
1167 | %options = (%options, @_) if @_; |
---|
1168 | |
---|
1169 | # Modify or generate the template |
---|
1170 | |
---|
1171 | # Deal with the DIR and TMPDIR options |
---|
1172 | if (defined $template) { |
---|
1173 | |
---|
1174 | # Need to strip directory path if using DIR or TMPDIR |
---|
1175 | if ($options{'TMPDIR'} || $options{'DIR'}) { |
---|
1176 | |
---|
1177 | # Strip parent directory from the filename |
---|
1178 | # |
---|
1179 | # There is no filename at the end |
---|
1180 | $template = VMS::Filespec::vmspath($template) if $^O eq 'VMS'; |
---|
1181 | my ($volume, $directories, undef) = File::Spec->splitpath( $template, 1); |
---|
1182 | |
---|
1183 | # Last directory is then our template |
---|
1184 | $template = (File::Spec->splitdir($directories))[-1]; |
---|
1185 | |
---|
1186 | # Prepend the supplied directory or temp dir |
---|
1187 | if ($options{"DIR"}) { |
---|
1188 | |
---|
1189 | $template = File::Spec->catdir($options{"DIR"}, $template); |
---|
1190 | |
---|
1191 | } elsif ($options{TMPDIR}) { |
---|
1192 | |
---|
1193 | # Prepend tmpdir |
---|
1194 | $template = File::Spec->catdir(File::Spec->tmpdir, $template); |
---|
1195 | |
---|
1196 | } |
---|
1197 | |
---|
1198 | } |
---|
1199 | |
---|
1200 | } else { |
---|
1201 | |
---|
1202 | if ($options{"DIR"}) { |
---|
1203 | |
---|
1204 | $template = File::Spec->catdir($options{"DIR"}, TEMPXXX); |
---|
1205 | |
---|
1206 | } else { |
---|
1207 | |
---|
1208 | $template = File::Spec->catdir(File::Spec->tmpdir, TEMPXXX); |
---|
1209 | |
---|
1210 | } |
---|
1211 | |
---|
1212 | } |
---|
1213 | |
---|
1214 | # Create the directory |
---|
1215 | my $tempdir; |
---|
1216 | my $suffixlen = 0; |
---|
1217 | if ($^O eq 'VMS') { # dir names can end in delimiters |
---|
1218 | $template =~ m/([\.\]:>]+)$/; |
---|
1219 | $suffixlen = length($1); |
---|
1220 | } |
---|
1221 | if ( ($^O eq 'MacOS') && (substr($template, -1) eq ':') ) { |
---|
1222 | # dir name has a trailing ':' |
---|
1223 | ++$suffixlen; |
---|
1224 | } |
---|
1225 | |
---|
1226 | my $errstr; |
---|
1227 | croak "Error in tempdir() using $template: $errstr" |
---|
1228 | unless ((undef, $tempdir) = _gettemp($template, |
---|
1229 | "open" => 0, |
---|
1230 | "mkdir"=> 1 , |
---|
1231 | "suffixlen" => $suffixlen, |
---|
1232 | "ErrStr" => \$errstr, |
---|
1233 | ) ); |
---|
1234 | |
---|
1235 | # Install exit handler; must be dynamic to get lexical |
---|
1236 | if ( $options{'CLEANUP'} && -d $tempdir) { |
---|
1237 | _deferred_unlink(undef, $tempdir, 1); |
---|
1238 | } |
---|
1239 | |
---|
1240 | # Return the dir name |
---|
1241 | return $tempdir; |
---|
1242 | |
---|
1243 | } |
---|
1244 | |
---|
1245 | =back |
---|
1246 | |
---|
1247 | =head1 MKTEMP FUNCTIONS |
---|
1248 | |
---|
1249 | The following functions are Perl implementations of the |
---|
1250 | mktemp() family of temp file generation system calls. |
---|
1251 | |
---|
1252 | =over 4 |
---|
1253 | |
---|
1254 | =item B<mkstemp> |
---|
1255 | |
---|
1256 | Given a template, returns a filehandle to the temporary file and the name |
---|
1257 | of the file. |
---|
1258 | |
---|
1259 | ($fh, $name) = mkstemp( $template ); |
---|
1260 | |
---|
1261 | In scalar context, just the filehandle is returned. |
---|
1262 | |
---|
1263 | The template may be any filename with some number of X's appended |
---|
1264 | to it, for example F</tmp/temp.XXXX>. The trailing X's are replaced |
---|
1265 | with unique alphanumeric combinations. |
---|
1266 | |
---|
1267 | =cut |
---|
1268 | |
---|
1269 | |
---|
1270 | |
---|
1271 | sub mkstemp { |
---|
1272 | |
---|
1273 | croak "Usage: mkstemp(template)" |
---|
1274 | if scalar(@_) != 1; |
---|
1275 | |
---|
1276 | my $template = shift; |
---|
1277 | |
---|
1278 | my ($fh, $path, $errstr); |
---|
1279 | croak "Error in mkstemp using $template: $errstr" |
---|
1280 | unless (($fh, $path) = _gettemp($template, |
---|
1281 | "open" => 1, |
---|
1282 | "mkdir"=> 0 , |
---|
1283 | "suffixlen" => 0, |
---|
1284 | "ErrStr" => \$errstr, |
---|
1285 | ) ); |
---|
1286 | |
---|
1287 | if (wantarray()) { |
---|
1288 | return ($fh, $path); |
---|
1289 | } else { |
---|
1290 | return $fh; |
---|
1291 | } |
---|
1292 | |
---|
1293 | } |
---|
1294 | |
---|
1295 | |
---|
1296 | =item B<mkstemps> |
---|
1297 | |
---|
1298 | Similar to mkstemp(), except that an extra argument can be supplied |
---|
1299 | with a suffix to be appended to the template. |
---|
1300 | |
---|
1301 | ($fh, $name) = mkstemps( $template, $suffix ); |
---|
1302 | |
---|
1303 | For example a template of C<testXXXXXX> and suffix of C<.dat> |
---|
1304 | would generate a file similar to F<testhGji_w.dat>. |
---|
1305 | |
---|
1306 | Returns just the filehandle alone when called in scalar context. |
---|
1307 | |
---|
1308 | =cut |
---|
1309 | |
---|
1310 | sub mkstemps { |
---|
1311 | |
---|
1312 | croak "Usage: mkstemps(template, suffix)" |
---|
1313 | if scalar(@_) != 2; |
---|
1314 | |
---|
1315 | |
---|
1316 | my $template = shift; |
---|
1317 | my $suffix = shift; |
---|
1318 | |
---|
1319 | $template .= $suffix; |
---|
1320 | |
---|
1321 | my ($fh, $path, $errstr); |
---|
1322 | croak "Error in mkstemps using $template: $errstr" |
---|
1323 | unless (($fh, $path) = _gettemp($template, |
---|
1324 | "open" => 1, |
---|
1325 | "mkdir"=> 0 , |
---|
1326 | "suffixlen" => length($suffix), |
---|
1327 | "ErrStr" => \$errstr, |
---|
1328 | ) ); |
---|
1329 | |
---|
1330 | if (wantarray()) { |
---|
1331 | return ($fh, $path); |
---|
1332 | } else { |
---|
1333 | return $fh; |
---|
1334 | } |
---|
1335 | |
---|
1336 | } |
---|
1337 | |
---|
1338 | =item B<mkdtemp> |
---|
1339 | |
---|
1340 | Create a directory from a template. The template must end in |
---|
1341 | X's that are replaced by the routine. |
---|
1342 | |
---|
1343 | $tmpdir_name = mkdtemp($template); |
---|
1344 | |
---|
1345 | Returns the name of the temporary directory created. |
---|
1346 | Returns undef on failure. |
---|
1347 | |
---|
1348 | Directory must be removed by the caller. |
---|
1349 | |
---|
1350 | =cut |
---|
1351 | |
---|
1352 | #' # for emacs |
---|
1353 | |
---|
1354 | sub mkdtemp { |
---|
1355 | |
---|
1356 | croak "Usage: mkdtemp(template)" |
---|
1357 | if scalar(@_) != 1; |
---|
1358 | |
---|
1359 | my $template = shift; |
---|
1360 | my $suffixlen = 0; |
---|
1361 | if ($^O eq 'VMS') { # dir names can end in delimiters |
---|
1362 | $template =~ m/([\.\]:>]+)$/; |
---|
1363 | $suffixlen = length($1); |
---|
1364 | } |
---|
1365 | if ( ($^O eq 'MacOS') && (substr($template, -1) eq ':') ) { |
---|
1366 | # dir name has a trailing ':' |
---|
1367 | ++$suffixlen; |
---|
1368 | } |
---|
1369 | my ($junk, $tmpdir, $errstr); |
---|
1370 | croak "Error creating temp directory from template $template\: $errstr" |
---|
1371 | unless (($junk, $tmpdir) = _gettemp($template, |
---|
1372 | "open" => 0, |
---|
1373 | "mkdir"=> 1 , |
---|
1374 | "suffixlen" => $suffixlen, |
---|
1375 | "ErrStr" => \$errstr, |
---|
1376 | ) ); |
---|
1377 | |
---|
1378 | return $tmpdir; |
---|
1379 | |
---|
1380 | } |
---|
1381 | |
---|
1382 | =item B<mktemp> |
---|
1383 | |
---|
1384 | Returns a valid temporary filename but does not guarantee |
---|
1385 | that the file will not be opened by someone else. |
---|
1386 | |
---|
1387 | $unopened_file = mktemp($template); |
---|
1388 | |
---|
1389 | Template is the same as that required by mkstemp(). |
---|
1390 | |
---|
1391 | =cut |
---|
1392 | |
---|
1393 | sub mktemp { |
---|
1394 | |
---|
1395 | croak "Usage: mktemp(template)" |
---|
1396 | if scalar(@_) != 1; |
---|
1397 | |
---|
1398 | my $template = shift; |
---|
1399 | |
---|
1400 | my ($tmpname, $junk, $errstr); |
---|
1401 | croak "Error getting name to temp file from template $template: $errstr" |
---|
1402 | unless (($junk, $tmpname) = _gettemp($template, |
---|
1403 | "open" => 0, |
---|
1404 | "mkdir"=> 0 , |
---|
1405 | "suffixlen" => 0, |
---|
1406 | "ErrStr" => \$errstr, |
---|
1407 | ) ); |
---|
1408 | |
---|
1409 | return $tmpname; |
---|
1410 | } |
---|
1411 | |
---|
1412 | =back |
---|
1413 | |
---|
1414 | =head1 POSIX FUNCTIONS |
---|
1415 | |
---|
1416 | This section describes the re-implementation of the tmpnam() |
---|
1417 | and tmpfile() functions described in L<POSIX> |
---|
1418 | using the mkstemp() from this module. |
---|
1419 | |
---|
1420 | Unlike the L<POSIX|POSIX> implementations, the directory used |
---|
1421 | for the temporary file is not specified in a system include |
---|
1422 | file (C<P_tmpdir>) but simply depends on the choice of tmpdir() |
---|
1423 | returned by L<File::Spec|File::Spec>. On some implementations this |
---|
1424 | location can be set using the C<TMPDIR> environment variable, which |
---|
1425 | may not be secure. |
---|
1426 | If this is a problem, simply use mkstemp() and specify a template. |
---|
1427 | |
---|
1428 | =over 4 |
---|
1429 | |
---|
1430 | =item B<tmpnam> |
---|
1431 | |
---|
1432 | When called in scalar context, returns the full name (including path) |
---|
1433 | of a temporary file (uses mktemp()). The only check is that the file does |
---|
1434 | not already exist, but there is no guarantee that that condition will |
---|
1435 | continue to apply. |
---|
1436 | |
---|
1437 | $file = tmpnam(); |
---|
1438 | |
---|
1439 | When called in list context, a filehandle to the open file and |
---|
1440 | a filename are returned. This is achieved by calling mkstemp() |
---|
1441 | after constructing a suitable template. |
---|
1442 | |
---|
1443 | ($fh, $file) = tmpnam(); |
---|
1444 | |
---|
1445 | If possible, this form should be used to prevent possible |
---|
1446 | race conditions. |
---|
1447 | |
---|
1448 | See L<File::Spec/tmpdir> for information on the choice of temporary |
---|
1449 | directory for a particular operating system. |
---|
1450 | |
---|
1451 | =cut |
---|
1452 | |
---|
1453 | sub tmpnam { |
---|
1454 | |
---|
1455 | # Retrieve the temporary directory name |
---|
1456 | my $tmpdir = File::Spec->tmpdir; |
---|
1457 | |
---|
1458 | croak "Error temporary directory is not writable" |
---|
1459 | if $tmpdir eq ''; |
---|
1460 | |
---|
1461 | # Use a ten character template and append to tmpdir |
---|
1462 | my $template = File::Spec->catfile($tmpdir, TEMPXXX); |
---|
1463 | |
---|
1464 | if (wantarray() ) { |
---|
1465 | return mkstemp($template); |
---|
1466 | } else { |
---|
1467 | return mktemp($template); |
---|
1468 | } |
---|
1469 | |
---|
1470 | } |
---|
1471 | |
---|
1472 | =item B<tmpfile> |
---|
1473 | |
---|
1474 | In scalar context, returns the filehandle of a temporary file. |
---|
1475 | |
---|
1476 | $fh = tmpfile(); |
---|
1477 | |
---|
1478 | The file is removed when the filehandle is closed or when the program |
---|
1479 | exits. No access to the filename is provided. |
---|
1480 | |
---|
1481 | If the temporary file can not be created undef is returned. |
---|
1482 | Currently this command will probably not work when the temporary |
---|
1483 | directory is on an NFS file system. |
---|
1484 | |
---|
1485 | =cut |
---|
1486 | |
---|
1487 | sub tmpfile { |
---|
1488 | |
---|
1489 | # Simply call tmpnam() in a list context |
---|
1490 | my ($fh, $file) = tmpnam(); |
---|
1491 | |
---|
1492 | # Make sure file is removed when filehandle is closed |
---|
1493 | # This will fail on NFS |
---|
1494 | unlink0($fh, $file) |
---|
1495 | or return undef; |
---|
1496 | |
---|
1497 | return $fh; |
---|
1498 | |
---|
1499 | } |
---|
1500 | |
---|
1501 | =back |
---|
1502 | |
---|
1503 | =head1 ADDITIONAL FUNCTIONS |
---|
1504 | |
---|
1505 | These functions are provided for backwards compatibility |
---|
1506 | with common tempfile generation C library functions. |
---|
1507 | |
---|
1508 | They are not exported and must be addressed using the full package |
---|
1509 | name. |
---|
1510 | |
---|
1511 | =over 4 |
---|
1512 | |
---|
1513 | =item B<tempnam> |
---|
1514 | |
---|
1515 | Return the name of a temporary file in the specified directory |
---|
1516 | using a prefix. The file is guaranteed not to exist at the time |
---|
1517 | the function was called, but such guarantees are good for one |
---|
1518 | clock tick only. Always use the proper form of C<sysopen> |
---|
1519 | with C<O_CREAT | O_EXCL> if you must open such a filename. |
---|
1520 | |
---|
1521 | $filename = File::Temp::tempnam( $dir, $prefix ); |
---|
1522 | |
---|
1523 | Equivalent to running mktemp() with $dir/$prefixXXXXXXXX |
---|
1524 | (using unix file convention as an example) |
---|
1525 | |
---|
1526 | Because this function uses mktemp(), it can suffer from race conditions. |
---|
1527 | |
---|
1528 | =cut |
---|
1529 | |
---|
1530 | sub tempnam { |
---|
1531 | |
---|
1532 | croak 'Usage tempnam($dir, $prefix)' unless scalar(@_) == 2; |
---|
1533 | |
---|
1534 | my ($dir, $prefix) = @_; |
---|
1535 | |
---|
1536 | # Add a string to the prefix |
---|
1537 | $prefix .= 'XXXXXXXX'; |
---|
1538 | |
---|
1539 | # Concatenate the directory to the file |
---|
1540 | my $template = File::Spec->catfile($dir, $prefix); |
---|
1541 | |
---|
1542 | return mktemp($template); |
---|
1543 | |
---|
1544 | } |
---|
1545 | |
---|
1546 | =back |
---|
1547 | |
---|
1548 | =head1 UTILITY FUNCTIONS |
---|
1549 | |
---|
1550 | Useful functions for dealing with the filehandle and filename. |
---|
1551 | |
---|
1552 | =over 4 |
---|
1553 | |
---|
1554 | =item B<unlink0> |
---|
1555 | |
---|
1556 | Given an open filehandle and the associated filename, make a safe |
---|
1557 | unlink. This is achieved by first checking that the filename and |
---|
1558 | filehandle initially point to the same file and that the number of |
---|
1559 | links to the file is 1 (all fields returned by stat() are compared). |
---|
1560 | Then the filename is unlinked and the filehandle checked once again to |
---|
1561 | verify that the number of links on that file is now 0. This is the |
---|
1562 | closest you can come to making sure that the filename unlinked was the |
---|
1563 | same as the file whose descriptor you hold. |
---|
1564 | |
---|
1565 | unlink0($fh, $path) or die "Error unlinking file $path safely"; |
---|
1566 | |
---|
1567 | Returns false on error. The filehandle is not closed since on some |
---|
1568 | occasions this is not required. |
---|
1569 | |
---|
1570 | On some platforms, for example Windows NT, it is not possible to |
---|
1571 | unlink an open file (the file must be closed first). On those |
---|
1572 | platforms, the actual unlinking is deferred until the program ends and |
---|
1573 | good status is returned. A check is still performed to make sure that |
---|
1574 | the filehandle and filename are pointing to the same thing (but not at |
---|
1575 | the time the end block is executed since the deferred removal may not |
---|
1576 | have access to the filehandle). |
---|
1577 | |
---|
1578 | Additionally, on Windows NT not all the fields returned by stat() can |
---|
1579 | be compared. For example, the C<dev> and C<rdev> fields seem to be |
---|
1580 | different. Also, it seems that the size of the file returned by stat() |
---|
1581 | does not always agree, with C<stat(FH)> being more accurate than |
---|
1582 | C<stat(filename)>, presumably because of caching issues even when |
---|
1583 | using autoflush (this is usually overcome by waiting a while after |
---|
1584 | writing to the tempfile before attempting to C<unlink0> it). |
---|
1585 | |
---|
1586 | Finally, on NFS file systems the link count of the file handle does |
---|
1587 | not always go to zero immediately after unlinking. Currently, this |
---|
1588 | command is expected to fail on NFS disks. |
---|
1589 | |
---|
1590 | =cut |
---|
1591 | |
---|
1592 | sub unlink0 { |
---|
1593 | |
---|
1594 | croak 'Usage: unlink0(filehandle, filename)' |
---|
1595 | unless scalar(@_) == 2; |
---|
1596 | |
---|
1597 | # Read args |
---|
1598 | my ($fh, $path) = @_; |
---|
1599 | |
---|
1600 | warn "Unlinking $path using unlink0\n" |
---|
1601 | if $DEBUG; |
---|
1602 | |
---|
1603 | # Stat the filehandle |
---|
1604 | my @fh = stat $fh; |
---|
1605 | |
---|
1606 | if ($fh[3] > 1 && $^W) { |
---|
1607 | carp "unlink0: fstat found too many links; SB=@fh" if $^W; |
---|
1608 | } |
---|
1609 | |
---|
1610 | # Stat the path |
---|
1611 | my @path = stat $path; |
---|
1612 | |
---|
1613 | unless (@path) { |
---|
1614 | carp "unlink0: $path is gone already" if $^W; |
---|
1615 | return; |
---|
1616 | } |
---|
1617 | |
---|
1618 | # this is no longer a file, but may be a directory, or worse |
---|
1619 | unless (-f _) { |
---|
1620 | confess "panic: $path is no longer a file: SB=@fh"; |
---|
1621 | } |
---|
1622 | |
---|
1623 | # Do comparison of each member of the array |
---|
1624 | # On WinNT dev and rdev seem to be different |
---|
1625 | # depending on whether it is a file or a handle. |
---|
1626 | # Cannot simply compare all members of the stat return |
---|
1627 | # Select the ones we can use |
---|
1628 | my @okstat = (0..$#fh); # Use all by default |
---|
1629 | if ($^O eq 'MSWin32') { |
---|
1630 | @okstat = (1,2,3,4,5,7,8,9,10); |
---|
1631 | } elsif ($^O eq 'os2') { |
---|
1632 | @okstat = (0, 2..$#fh); |
---|
1633 | } elsif ($^O eq 'VMS') { # device and file ID are sufficient |
---|
1634 | @okstat = (0, 1); |
---|
1635 | } elsif ($^O eq 'dos') { |
---|
1636 | @okstat = (0,2..7,11..$#fh); |
---|
1637 | } |
---|
1638 | |
---|
1639 | # Now compare each entry explicitly by number |
---|
1640 | for (@okstat) { |
---|
1641 | print "Comparing: $_ : $fh[$_] and $path[$_]\n" if $DEBUG; |
---|
1642 | # Use eq rather than == since rdev, blksize, and blocks (6, 11, |
---|
1643 | # and 12) will be '' on platforms that do not support them. This |
---|
1644 | # is fine since we are only comparing integers. |
---|
1645 | unless ($fh[$_] eq $path[$_]) { |
---|
1646 | warn "Did not match $_ element of stat\n" if $DEBUG; |
---|
1647 | return 0; |
---|
1648 | } |
---|
1649 | } |
---|
1650 | |
---|
1651 | # attempt remove the file (does not work on some platforms) |
---|
1652 | if (_can_unlink_opened_file()) { |
---|
1653 | # XXX: do *not* call this on a directory; possible race |
---|
1654 | # resulting in recursive removal |
---|
1655 | croak "unlink0: $path has become a directory!" if -d $path; |
---|
1656 | unlink($path) or return 0; |
---|
1657 | |
---|
1658 | # Stat the filehandle |
---|
1659 | @fh = stat $fh; |
---|
1660 | |
---|
1661 | print "Link count = $fh[3] \n" if $DEBUG; |
---|
1662 | |
---|
1663 | # Make sure that the link count is zero |
---|
1664 | # - Cygwin provides deferred unlinking, however, |
---|
1665 | # on Win9x the link count remains 1 |
---|
1666 | # On NFS the link count may still be 1 but we cant know that |
---|
1667 | # we are on NFS |
---|
1668 | return ( $fh[3] == 0 or $^O eq 'cygwin' ? 1 : 0); |
---|
1669 | |
---|
1670 | } else { |
---|
1671 | _deferred_unlink($fh, $path, 0); |
---|
1672 | return 1; |
---|
1673 | } |
---|
1674 | |
---|
1675 | } |
---|
1676 | |
---|
1677 | =back |
---|
1678 | |
---|
1679 | =head1 PACKAGE VARIABLES |
---|
1680 | |
---|
1681 | These functions control the global state of the package. |
---|
1682 | |
---|
1683 | =over 4 |
---|
1684 | |
---|
1685 | =item B<safe_level> |
---|
1686 | |
---|
1687 | Controls the lengths to which the module will go to check the safety of the |
---|
1688 | temporary file or directory before proceeding. |
---|
1689 | Options are: |
---|
1690 | |
---|
1691 | =over 8 |
---|
1692 | |
---|
1693 | =item STANDARD |
---|
1694 | |
---|
1695 | Do the basic security measures to ensure the directory exists and |
---|
1696 | is writable, that the umask() is fixed before opening of the file, |
---|
1697 | that temporary files are opened only if they do not already exist, and |
---|
1698 | that possible race conditions are avoided. Finally the L<unlink0|"unlink0"> |
---|
1699 | function is used to remove files safely. |
---|
1700 | |
---|
1701 | =item MEDIUM |
---|
1702 | |
---|
1703 | In addition to the STANDARD security, the output directory is checked |
---|
1704 | to make sure that it is owned either by root or the user running the |
---|
1705 | program. If the directory is writable by group or by other, it is then |
---|
1706 | checked to make sure that the sticky bit is set. |
---|
1707 | |
---|
1708 | Will not work on platforms that do not support the C<-k> test |
---|
1709 | for sticky bit. |
---|
1710 | |
---|
1711 | =item HIGH |
---|
1712 | |
---|
1713 | In addition to the MEDIUM security checks, also check for the |
---|
1714 | possibility of ``chown() giveaway'' using the L<POSIX|POSIX> |
---|
1715 | sysconf() function. If this is a possibility, each directory in the |
---|
1716 | path is checked in turn for safeness, recursively walking back to the |
---|
1717 | root directory. |
---|
1718 | |
---|
1719 | For platforms that do not support the L<POSIX|POSIX> |
---|
1720 | C<_PC_CHOWN_RESTRICTED> symbol (for example, Windows NT) it is |
---|
1721 | assumed that ``chown() giveaway'' is possible and the recursive test |
---|
1722 | is performed. |
---|
1723 | |
---|
1724 | =back |
---|
1725 | |
---|
1726 | The level can be changed as follows: |
---|
1727 | |
---|
1728 | File::Temp->safe_level( File::Temp::HIGH ); |
---|
1729 | |
---|
1730 | The level constants are not exported by the module. |
---|
1731 | |
---|
1732 | Currently, you must be running at least perl v5.6.0 in order to |
---|
1733 | run with MEDIUM or HIGH security. This is simply because the |
---|
1734 | safety tests use functions from L<Fcntl|Fcntl> that are not |
---|
1735 | available in older versions of perl. The problem is that the version |
---|
1736 | number for Fcntl is the same in perl 5.6.0 and in 5.005_03 even though |
---|
1737 | they are different versions. |
---|
1738 | |
---|
1739 | On systems that do not support the HIGH or MEDIUM safety levels |
---|
1740 | (for example Win NT or OS/2) any attempt to change the level will |
---|
1741 | be ignored. The decision to ignore rather than raise an exception |
---|
1742 | allows portable programs to be written with high security in mind |
---|
1743 | for the systems that can support this without those programs failing |
---|
1744 | on systems where the extra tests are irrelevant. |
---|
1745 | |
---|
1746 | If you really need to see whether the change has been accepted |
---|
1747 | simply examine the return value of C<safe_level>. |
---|
1748 | |
---|
1749 | $newlevel = File::Temp->safe_level( File::Temp::HIGH ); |
---|
1750 | die "Could not change to high security" |
---|
1751 | if $newlevel != File::Temp::HIGH; |
---|
1752 | |
---|
1753 | =cut |
---|
1754 | |
---|
1755 | { |
---|
1756 | # protect from using the variable itself |
---|
1757 | my $LEVEL = STANDARD; |
---|
1758 | sub safe_level { |
---|
1759 | my $self = shift; |
---|
1760 | if (@_) { |
---|
1761 | my $level = shift; |
---|
1762 | if (($level != STANDARD) && ($level != MEDIUM) && ($level != HIGH)) { |
---|
1763 | carp "safe_level: Specified level ($level) not STANDARD, MEDIUM or HIGH - ignoring\n" if $^W; |
---|
1764 | } else { |
---|
1765 | # Dont allow this on perl 5.005 or earlier |
---|
1766 | if ($] < 5.006 && $level != STANDARD) { |
---|
1767 | # Cant do MEDIUM or HIGH checks |
---|
1768 | croak "Currently requires perl 5.006 or newer to do the safe checks"; |
---|
1769 | } |
---|
1770 | # Check that we are allowed to change level |
---|
1771 | # Silently ignore if we can not. |
---|
1772 | $LEVEL = $level if _can_do_level($level); |
---|
1773 | } |
---|
1774 | } |
---|
1775 | return $LEVEL; |
---|
1776 | } |
---|
1777 | } |
---|
1778 | |
---|
1779 | =item TopSystemUID |
---|
1780 | |
---|
1781 | This is the highest UID on the current system that refers to a root |
---|
1782 | UID. This is used to make sure that the temporary directory is |
---|
1783 | owned by a system UID (C<root>, C<bin>, C<sys> etc) rather than |
---|
1784 | simply by root. |
---|
1785 | |
---|
1786 | This is required since on many unix systems C</tmp> is not owned |
---|
1787 | by root. |
---|
1788 | |
---|
1789 | Default is to assume that any UID less than or equal to 10 is a root |
---|
1790 | UID. |
---|
1791 | |
---|
1792 | File::Temp->top_system_uid(10); |
---|
1793 | my $topid = File::Temp->top_system_uid; |
---|
1794 | |
---|
1795 | This value can be adjusted to reduce security checking if required. |
---|
1796 | The value is only relevant when C<safe_level> is set to MEDIUM or higher. |
---|
1797 | |
---|
1798 | =back |
---|
1799 | |
---|
1800 | =cut |
---|
1801 | |
---|
1802 | { |
---|
1803 | my $TopSystemUID = 10; |
---|
1804 | sub top_system_uid { |
---|
1805 | my $self = shift; |
---|
1806 | if (@_) { |
---|
1807 | my $newuid = shift; |
---|
1808 | croak "top_system_uid: UIDs should be numeric" |
---|
1809 | unless $newuid =~ /^\d+$/s; |
---|
1810 | $TopSystemUID = $newuid; |
---|
1811 | } |
---|
1812 | return $TopSystemUID; |
---|
1813 | } |
---|
1814 | } |
---|
1815 | |
---|
1816 | =head1 WARNING |
---|
1817 | |
---|
1818 | For maximum security, endeavour always to avoid ever looking at, |
---|
1819 | touching, or even imputing the existence of the filename. You do not |
---|
1820 | know that that filename is connected to the same file as the handle |
---|
1821 | you have, and attempts to check this can only trigger more race |
---|
1822 | conditions. It's far more secure to use the filehandle alone and |
---|
1823 | dispense with the filename altogether. |
---|
1824 | |
---|
1825 | If you need to pass the handle to something that expects a filename |
---|
1826 | then, on a unix system, use C<"/dev/fd/" . fileno($fh)> for arbitrary |
---|
1827 | programs, or more generally C<< "+<=&" . fileno($fh) >> for Perl |
---|
1828 | programs. You will have to clear the close-on-exec bit on that file |
---|
1829 | descriptor before passing it to another process. |
---|
1830 | |
---|
1831 | use Fcntl qw/F_SETFD F_GETFD/; |
---|
1832 | fcntl($tmpfh, F_SETFD, 0) |
---|
1833 | or die "Can't clear close-on-exec flag on temp fh: $!\n"; |
---|
1834 | |
---|
1835 | =head2 Temporary files and NFS |
---|
1836 | |
---|
1837 | Some problems are associated with using temporary files that reside |
---|
1838 | on NFS file systems and it is recommended that a local filesystem |
---|
1839 | is used whenever possible. Some of the security tests will most probably |
---|
1840 | fail when the temp file is not local. Additionally, be aware that |
---|
1841 | the performance of I/O operations over NFS will not be as good as for |
---|
1842 | a local disk. |
---|
1843 | |
---|
1844 | =head1 HISTORY |
---|
1845 | |
---|
1846 | Originally began life in May 1999 as an XS interface to the system |
---|
1847 | mkstemp() function. In March 2000, the OpenBSD mkstemp() code was |
---|
1848 | translated to Perl for total control of the code's |
---|
1849 | security checking, to ensure the presence of the function regardless of |
---|
1850 | operating system and to help with portability. |
---|
1851 | |
---|
1852 | =head1 SEE ALSO |
---|
1853 | |
---|
1854 | L<POSIX/tmpnam>, L<POSIX/tmpfile>, L<File::Spec>, L<File::Path> |
---|
1855 | |
---|
1856 | See L<IO::File> and L<File::MkTemp> for different implementations of |
---|
1857 | temporary file handling. |
---|
1858 | |
---|
1859 | =head1 AUTHOR |
---|
1860 | |
---|
1861 | Tim Jenness E<lt>t.jenness@jach.hawaii.eduE<gt> |
---|
1862 | |
---|
1863 | Copyright (C) 1999-2001 Tim Jenness and the UK Particle Physics and |
---|
1864 | Astronomy Research Council. All Rights Reserved. This program is free |
---|
1865 | software; you can redistribute it and/or modify it under the same |
---|
1866 | terms as Perl itself. |
---|
1867 | |
---|
1868 | Original Perl implementation loosely based on the OpenBSD C code for |
---|
1869 | mkstemp(). Thanks to Tom Christiansen for suggesting that this module |
---|
1870 | should be written and providing ideas for code improvements and |
---|
1871 | security enhancements. |
---|
1872 | |
---|
1873 | =cut |
---|
1874 | |
---|
1875 | |
---|
1876 | 1; |
---|