1 | /* |
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2 | * Copyright (c) 1987 Regents of the University of California. |
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3 | * All rights reserved. |
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4 | * |
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5 | * Redistribution and use in source and binary forms are permitted |
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6 | * provided that: (1) source distributions retain this entire copyright |
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7 | * notice and comment, and (2) distributions including binaries display |
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8 | * the following acknowledgement: ``This product includes software |
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9 | * developed by the University of California, Berkeley and its contributors'' |
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10 | * in the documentation or other materials provided with the distribution |
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11 | * and in all advertising materials mentioning features or use of this |
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12 | * software. Neither the name of the University nor the names of its |
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13 | * contributors may be used to endorse or promote products derived |
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14 | * from this software without specific prior written permission. |
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15 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
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16 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
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17 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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18 | */ |
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19 | /* This is file MKTEMP.C */ |
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20 | /* This file may have been modified by DJ Delorie (Jan 1991). If so, |
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21 | ** these modifications are Copyright (C) 1991 DJ Delorie. |
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22 | */ |
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23 | |
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24 | /* |
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25 | FUNCTION |
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26 | <<mktemp>>, <<mkstemp>>, <<mkostemp>>, <<mkstemps>>, |
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27 | <<mkostemps>>---generate unused file name |
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28 | <<mkdtemp>>---generate unused directory |
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29 | |
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30 | INDEX |
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31 | mktemp |
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32 | INDEX |
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33 | mkdtemp |
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34 | INDEX |
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35 | mkstemp |
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36 | INDEX |
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37 | mkstemps |
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38 | INDEX |
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39 | mkostemp |
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40 | INDEX |
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41 | mkostemps |
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42 | INDEX |
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43 | _mktemp_r |
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44 | INDEX |
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45 | _mkdtemp_r |
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46 | INDEX |
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47 | _mkstemp_r |
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48 | INDEX |
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49 | _mkstemps_r |
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50 | INDEX |
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51 | _mkostemp_r |
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52 | INDEX |
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53 | _mkostemps_r |
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54 | |
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55 | SYNOPSIS |
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56 | #include <stdlib.h> |
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57 | char *mktemp(char *<[path]>); |
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58 | char *mkdtemp(char *<[path]>); |
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59 | int mkstemp(char *<[path]>); |
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60 | int mkstemps(char *<[path]>, int <[suffixlen]>); |
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61 | int mkostemp(char *<[path]>, int <[flags]>); |
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62 | int mkostemps(char *<[path]>, int <[suffixlen]>, int <[flags]>); |
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63 | |
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64 | char *_mktemp_r(struct _reent *<[reent]>, char *<[path]>); |
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65 | char *_mkdtemp_r(struct _reent *<[reent]>, char *<[path]>); |
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66 | int *_mkstemp_r(struct _reent *<[reent]>, char *<[path]>); |
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67 | int *_mkstemps_r(struct _reent *<[reent]>, char *<[path]>, int <[len]>); |
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68 | int *_mkostemp_r(struct _reent *<[reent]>, char *<[path]>, |
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69 | int <[flags]>); |
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70 | int *_mkostemps_r(struct _reent *<[reent]>, char *<[path]>, int <[len]>, |
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71 | int <[flags]>); |
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72 | |
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73 | DESCRIPTION |
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74 | <<mktemp>>, <<mkstemp>>, and <<mkstemps>> attempt to generate a file name |
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75 | that is not yet in use for any existing file. <<mkstemp>> and <<mkstemps>> |
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76 | create the file and open it for reading and writing; <<mktemp>> simply |
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77 | generates the file name (making <<mktemp>> a security risk). <<mkostemp>> |
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78 | and <<mkostemps>> allow the addition of other <<open>> flags, such |
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79 | as <<O_CLOEXEC>>, <<O_APPEND>>, or <<O_SYNC>>. On platforms with a |
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80 | separate text mode, <<mkstemp>> forces <<O_BINARY>>, while <<mkostemp>> |
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81 | allows the choice between <<O_BINARY>>, <<O_TEXT>>, or 0 for default. |
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82 | <<mkdtemp>> attempts to create a directory instead of a file, with a |
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83 | permissions mask of 0700. |
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84 | |
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85 | You supply a simple pattern for the generated file name, as the string |
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86 | at <[path]>. The pattern should be a valid filename (including path |
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87 | information if you wish) ending with at least six `<<X>>' |
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88 | characters. The generated filename will match the leading part of the |
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89 | name you supply, with the trailing `<<X>>' characters replaced by some |
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90 | combination of digits and letters. With <<mkstemps>>, the `<<X>>' |
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91 | characters end <[suffixlen]> bytes before the end of the string. |
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92 | |
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93 | The alternate functions <<_mktemp_r>>, <<_mkdtemp_r>>, <<_mkstemp_r>>, |
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94 | <<_mkostemp_r>>, <<_mkostemps_r>>, and <<_mkstemps_r>> are reentrant |
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95 | versions. The extra argument <[reent]> is a pointer to a reentrancy |
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96 | structure. |
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97 | |
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98 | RETURNS |
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99 | <<mktemp>> returns the pointer <[path]> to the modified string |
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100 | representing an unused filename, unless it could not generate one, or |
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101 | the pattern you provided is not suitable for a filename; in that case, |
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102 | it returns <<NULL>>. Be aware that there is an inherent race between |
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103 | generating the name and attempting to create a file by that name; |
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104 | you are advised to use <<O_EXCL|O_CREAT>>. |
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105 | |
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106 | <<mkdtemp>> returns the pointer <[path]> to the modified string if the |
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107 | directory was created, otherwise it returns <<NULL>>. |
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108 | |
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109 | <<mkstemp>>, <<mkstemps>>, <<mkostemp>>, and <<mkostemps>> return a file |
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110 | descriptor to the newly created file, unless it could not generate an |
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111 | unused filename, or the pattern you provided is not suitable for a |
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112 | filename; in that case, it returns <<-1>>. |
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113 | |
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114 | NOTES |
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115 | Never use <<mktemp>>. The generated filenames are easy to guess and |
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116 | there's a race between the test if the file exists and the creation |
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117 | of the file. In combination this makes <<mktemp>> prone to attacks |
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118 | and using it is a security risk. Whenever possible use <<mkstemp>> |
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119 | instead. It doesn't suffer the race condition. |
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120 | |
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121 | PORTABILITY |
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122 | ANSI C does not require either <<mktemp>> or <<mkstemp>>; the System |
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123 | V Interface Definition requires <<mktemp>> as of Issue 2. POSIX 2001 |
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124 | requires <<mkstemp>>, and POSIX 2008 requires <<mkdtemp>> while |
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125 | deprecating <<mktemp>>. <<mkstemps>>, <<mkostemp>>, and <<mkostemps>> |
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126 | are not standardized. |
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127 | |
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128 | Supporting OS subroutines required: <<getpid>>, <<mkdir>>, <<open>>, <<stat>>. |
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129 | */ |
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130 | |
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131 | #include <_ansi.h> |
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132 | #include <stdlib.h> |
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133 | #include <reent.h> |
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134 | #include <sys/types.h> |
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135 | #include <fcntl.h> |
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136 | #include <sys/stat.h> |
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137 | #include <errno.h> |
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138 | #include <stdio.h> |
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139 | #include <ctype.h> |
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140 | |
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141 | static int |
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142 | _gettemp (struct _reent *ptr, |
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143 | char *path, |
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144 | register int *doopen, |
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145 | int domkdir, |
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146 | size_t suffixlen, |
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147 | int flags) |
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148 | { |
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149 | register char *start, *trv; |
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150 | char *end; |
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151 | #ifdef __USE_INTERNAL_STAT64 |
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152 | struct stat64 sbuf; |
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153 | #else |
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154 | struct stat sbuf; |
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155 | #endif |
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156 | unsigned int pid; |
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157 | |
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158 | pid = _getpid_r (ptr); |
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159 | for (trv = path; *trv; ++trv) /* extra X's get set to 0's */ |
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160 | continue; |
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161 | if (trv - path < suffixlen) |
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162 | { |
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163 | ptr->_errno = EINVAL; |
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164 | return 0; |
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165 | } |
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166 | trv -= suffixlen; |
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167 | end = trv; |
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168 | while (path < trv && *--trv == 'X') |
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169 | { |
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170 | *trv = (pid % 10) + '0'; |
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171 | pid /= 10; |
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172 | } |
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173 | if (end - trv < 6) |
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174 | { |
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175 | ptr->_errno = EINVAL; |
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176 | return 0; |
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177 | } |
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178 | |
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179 | /* |
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180 | * Check the target directory; if you have six X's and it |
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181 | * doesn't exist this runs for a *very* long time. |
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182 | */ |
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183 | |
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184 | for (start = trv + 1;; --trv) |
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185 | { |
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186 | if (trv <= path) |
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187 | break; |
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188 | if (*trv == '/') |
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189 | { |
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190 | *trv = '\0'; |
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191 | #ifdef __USE_INTERNAL_STAT64 |
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192 | if (_stat64_r (ptr, path, &sbuf)) |
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193 | #else |
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194 | if (_stat_r (ptr, path, &sbuf)) |
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195 | #endif |
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196 | return (0); |
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197 | if (!(sbuf.st_mode & S_IFDIR)) |
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198 | { |
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199 | ptr->_errno = ENOTDIR; |
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200 | return (0); |
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201 | } |
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202 | *trv = '/'; |
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203 | break; |
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204 | } |
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205 | } |
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206 | |
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207 | for (;;) |
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208 | { |
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209 | #if !defined _ELIX_LEVEL || _ELIX_LEVEL >= 4 |
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210 | if (domkdir) |
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211 | { |
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212 | #ifdef HAVE_MKDIR |
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213 | if (_mkdir_r (ptr, path, 0700) == 0) |
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214 | return 1; |
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215 | if (ptr->_errno != EEXIST) |
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216 | return 0; |
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217 | #else /* !HAVE_MKDIR */ |
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218 | ptr->_errno = ENOSYS; |
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219 | return 0; |
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220 | #endif /* !HAVE_MKDIR */ |
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221 | } |
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222 | else |
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223 | #endif /* _ELIX_LEVEL */ |
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224 | if (doopen) |
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225 | { |
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226 | if ((*doopen = _open_r (ptr, path, O_CREAT | O_EXCL | O_RDWR | flags, |
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227 | 0600)) >= 0) |
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228 | return 1; |
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229 | if (ptr->_errno != EEXIST) |
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230 | return 0; |
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231 | } |
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232 | #ifdef __USE_INTERNAL_STAT64 |
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233 | else if (_stat64_r (ptr, path, &sbuf)) |
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234 | #else |
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235 | else if (_stat_r (ptr, path, &sbuf)) |
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236 | #endif |
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237 | return (ptr->_errno == ENOENT ? 1 : 0); |
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238 | |
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239 | /* tricky little algorithm for backward compatibility */ |
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240 | for (trv = start;;) |
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241 | { |
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242 | if (trv == end) |
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243 | return 0; |
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244 | if (*trv == 'z') |
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245 | *trv++ = 'a'; |
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246 | else |
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247 | { |
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248 | /* Safe, since it only encounters 7-bit characters. */ |
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249 | if (isdigit ((unsigned char) *trv)) |
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250 | *trv = 'a'; |
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251 | else |
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252 | ++ * trv; |
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253 | break; |
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254 | } |
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255 | } |
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256 | } |
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257 | /*NOTREACHED*/ |
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258 | } |
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259 | |
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260 | #ifndef O_BINARY |
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261 | # define O_BINARY 0 |
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262 | #endif |
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263 | |
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264 | int |
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265 | _mkstemp_r (struct _reent *ptr, |
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266 | char *path) |
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267 | { |
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268 | int fd; |
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269 | |
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270 | return (_gettemp (ptr, path, &fd, 0, 0, O_BINARY) ? fd : -1); |
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271 | } |
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272 | |
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273 | #if !defined _ELIX_LEVEL || _ELIX_LEVEL >= 4 |
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274 | char * |
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275 | _mkdtemp_r (struct _reent *ptr, |
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276 | char *path) |
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277 | { |
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278 | return (_gettemp (ptr, path, (int *) NULL, 1, 0, 0) ? path : NULL); |
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279 | } |
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280 | |
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281 | int |
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282 | _mkstemps_r (struct _reent *ptr, |
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283 | char *path, |
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284 | int len) |
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285 | { |
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286 | int fd; |
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287 | |
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288 | return (_gettemp (ptr, path, &fd, 0, len, O_BINARY) ? fd : -1); |
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289 | } |
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290 | |
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291 | int |
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292 | _mkostemp_r (struct _reent *ptr, |
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293 | char *path, |
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294 | int flags) |
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295 | { |
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296 | int fd; |
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297 | |
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298 | return (_gettemp (ptr, path, &fd, 0, 0, flags & ~O_ACCMODE) ? fd : -1); |
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299 | } |
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300 | |
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301 | int |
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302 | _mkostemps_r (struct _reent *ptr, |
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303 | char *path, |
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304 | int len, |
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305 | int flags) |
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306 | { |
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307 | int fd; |
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308 | |
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309 | return (_gettemp (ptr, path, &fd, 0, len, flags & ~O_ACCMODE) ? fd : -1); |
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310 | } |
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311 | #endif /* _ELIX_LEVEL */ |
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312 | |
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313 | char * |
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314 | _mktemp_r (struct _reent *ptr, |
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315 | char *path) |
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316 | { |
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317 | return (_gettemp (ptr, path, (int *) NULL, 0, 0, 0) ? path : (char *) NULL); |
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318 | } |
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319 | |
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320 | #ifndef _REENT_ONLY |
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321 | |
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322 | int |
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323 | mkstemp (char *path) |
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324 | { |
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325 | int fd; |
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326 | |
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327 | return (_gettemp (_REENT, path, &fd, 0, 0, O_BINARY) ? fd : -1); |
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328 | } |
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329 | |
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330 | # if !defined _ELIX_LEVEL || _ELIX_LEVEL >= 4 |
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331 | char * |
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332 | mkdtemp (char *path) |
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333 | { |
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334 | return (_gettemp (_REENT, path, (int *) NULL, 1, 0, 0) ? path : NULL); |
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335 | } |
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336 | |
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337 | int |
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338 | mkstemps (char *path, |
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339 | int len) |
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340 | { |
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341 | int fd; |
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342 | |
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343 | return (_gettemp (_REENT, path, &fd, 0, len, O_BINARY) ? fd : -1); |
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344 | } |
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345 | |
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346 | int |
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347 | mkostemp (char *path, |
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348 | int flags) |
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349 | { |
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350 | int fd; |
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351 | |
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352 | return (_gettemp (_REENT, path, &fd, 0, 0, flags & ~O_ACCMODE) ? fd : -1); |
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353 | } |
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354 | |
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355 | int |
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356 | mkostemps (char *path, |
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357 | int len, |
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358 | int flags) |
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359 | { |
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360 | int fd; |
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361 | |
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362 | return (_gettemp (_REENT, path, &fd, 0, len, flags & ~O_ACCMODE) ? fd : -1); |
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363 | } |
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364 | # endif /* _ELIX_LEVEL */ |
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365 | |
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366 | char * |
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367 | mktemp (char *path) |
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368 | { |
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369 | return (_gettemp (_REENT, path, (int *) NULL, 0, 0, 0) ? path : (char *) NULL); |
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370 | } |
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371 | |
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372 | #endif /* ! defined (_REENT_ONLY) */ |
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