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32 .\" @(#)tmpnam.3 8.2 (Berkeley) 11/17/93
42 .Nd temporary file routines
50 .Fn tmpnam "char *str"
52 .Fn tempnam "const char *tmpdir" "const char *prefix"
57 returns a pointer to a stream associated with a file descriptor returned
60 The created file is unlinked before
62 returns, causing the file to be automatically deleted when the last
63 reference to it is closed.
64 The file is opened with the access value
66 The file is created in the directory determined by the environment variable
69 The default location if
77 returns a pointer to a file name, in the
80 did not reference an existing file at some indeterminate point in the
83 is defined in the include file
89 the file name is copied to the buffer it references.
90 Otherwise, the file name is copied to a static buffer.
93 returns a pointer to the file name.
95 The buffer referenced by
97 is expected to be at least
101 is defined in the include file
109 but provides the ability to specify the directory which will
110 contain the temporary file and the file name prefix.
112 The environment variable
114 (if set), the argument
122 are tried, in the listed order, as directories in which to store the
129 is used to specify a file name prefix, which will be the
130 first part of the created file name.
134 allocates memory in which to store the file name; the returned pointer
135 may be used as a subsequent argument to
141 returns a pointer to an open file stream on success, and a
151 return a pointer to a file name on success, and a
163 the directory in which the temporary file is stored.
165 is ignored for processes
171 These interfaces are provided from System V and
175 Most historic implementations of these functions provide
176 only a limited number of possible temporary file names
178 before file names will start being recycled.
179 System V implementations of these functions
184 system call to determine whether or not the temporary file
186 This has obvious ramifications for setuid or setgid programs,
187 complicating the portable use of these interfaces in such programs.
191 interface should not be used in software expected to be used on other systems
192 if there is any possibility that the user does not wish the temporary file to
193 be publicly readable and writable.
198 may fail and set the global variable
200 for any of the errors specified for the library functions
210 for any of the errors specified for the library function
218 for any of the errors specified for the library functions
233 .Sh SECURITY CONSIDERATIONS
238 functions are susceptible to a race condition
239 occurring between the selection of the file name
240 and the creation of the file,
241 which allows malicious users
242 to potentially overwrite arbitrary files in the system,
243 depending on the level of privilege of the running program.
244 Additionally, there is no means by which
245 file permissions may be specified.
246 It is strongly suggested that
248 be used in place of these functions.