gen/confstr.3

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  32 .\"     @(#)confstr.3   8.1 (Berkeley) 6/4/93
  33 .\" $FreeBSD: src/lib/libc/gen/confstr.3,v 1.11 2001/10/01 16:08:50 ru Exp $
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  35 .Dd June 18, 2001
  36 .Dt CONFSTR 3
  37 .Os
  38 .Sh NAME
  39 .Nm confstr
  40 .Nd get string-valued configurable variables
  41 .Sh LIBRARY
  42 .Lb libc
  43 .Sh SYNOPSIS
  44 .In unistd.h
  45 .Ft size_t
  46 .Fn confstr "int name" "char *buf" "size_t len"
  47 .Sh DESCRIPTION
  48 This interface is specified by
  49 .\" .St -p1003.1-200x .
  50 .Tn POSIX .
  51 A more flexible (but non-portable) interface is provided by
  52 .Xr sysctl 3 .
  53 .Pp
  54 The
  55 .Fn confstr
  56 function provides a method for applications to get configuration
  57 defined string values.
  58 Shell programmers needing access to these parameters should use the
  59 .Xr getconf 1
  60 utility.
  61 .Pp
  62 The
  63 .Fa name
  64 argument specifies the system variable to be queried.
  65 Symbolic constants for each name value are found in the include file
  66 .Aq Pa unistd.h .
  67 The
  68 .Fa len
  69 argument specifies the size of the buffer referenced by the
  70 argument
  71 .Fa buf .
  72 If
  73 .Fa len
  74 is non-zero,
  75 .Fa buf
  76 is a non-null pointer, and
  77 .Fa name
  78 has a value, up to
  79 .Fa len
  80 \- 1 bytes of the value are copied into the buffer
  81 .Fa buf .
  82 The copied value is always null terminated.
  83 .Pp
  84 The available values are as follows:
  85 .Pp
  86 .Bl -tag -width 6n
  87 .Pp
  88 .It Li _CS_DARWIN_USER_DIR
  89 Provides the path to a user's folder. The directory will be created if it
  90 does not already exist.
  91 .Pp
  92 This directory is created with access permissions of 0755 and restricted by
  93 the
  94 .Xr umask 2
  95 of the calling process and is not intended to be used for
  96 sensitive or temporary file storage, as all users can see files created here.
  97 If the user's umask allows it, files created here will be world readable,
  98 which could lead to information disclosure.
  99 .Pp
 100 .It Li _CS_DARWIN_USER_TEMP_DIR
 101 Provides the path to a user's temporary items directory. The directory will be
 102 created it if does not already exist. This directory is created with access
 103 permissions of 0700 and restricted by the
 104 .Xr umask 2
 105 of the calling process and is a good location for temporary files.
 106 .Pp
 107 By default, files in this location may be cleaned (removed) by the system if
 108 they are not accessed in 3 days.
 109 .Pp
 110 .It Li _CS_DARWIN_USER_CACHE_DIR
 111 Provides the path to the user's cache directory. The directory will be created
 112 if it does not already exist. This directory is created with access permissions
 113 of 0700 and restricted by the
 114 .Xr umask 2
 115 of the calling process and is a good location for user cache data as it will not
 116 be automatically cleaned by the system.
 117 .Pp
 118 Files in this location will be removed during safe boot.
 119 .Pp
 120 .It Li _CS_PATH
 121 Return a value for the
 122 .Ev PATH
 123 environment variable that finds all the standard utilities.
 124 .El
 125 .Sh RETURN VALUES
 126 If the call to
 127 .Fn confstr
 128 is not successful, 0 is returned and
 129 .Va errno
 130 is set appropriately.
 131 Otherwise, if the variable does not have a configuration defined value,
 132 0 is returned and
 133 .Va errno
 134 is not modified.
 135 Otherwise, the buffer size needed to hold the entire configuration-defined
 136 value is returned.
 137 If this size is greater than the argument
 138 .Fa len ,
 139 the string in
 140 .Fa buf
 141 was truncated.
 142 .Sh ERRORS
 143 The
 144 .Fn confstr
 145 function may fail and set
 146 .Va errno
 147 for any of the errors specified for the library functions
 148 .Xr malloc 3
 149 and
 150 .Xr sysctl 3 .
 151 .Pp
 152 In addition, the following errors may be reported:
 153 .Bl -tag -width Er
 154 .It Bq Er EINVAL
 155 The value of the
 156 .Fa name
 157 argument is invalid.
 158 .It Bq Er ENOMEM
 159 Insufficient storage space is available.
 160 .It Bq Er EIO
 161 I/O error communicating with
 162 .Xr dirhelper 8 .
 163 .El
 164 .Sh LEGACY ERRORS
 165 If the call to
 166 .Fn confstr
 167 is not successful, \-1 (rather than 0) is returned and
 168 .Va errno
 169 is set appropriately.
 170 .Sh SEE ALSO
 171 .Xr getconf 1 ,
 172 .Xr pathconf 2 ,
 173 .Xr sysconf 3 ,
 174 .Xr sysctl 3
 175 .Sh HISTORY
 176 The
 177 .Fn confstr
 178 function first appeared in
 179 .Bx 4.4 .