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34 .Nd kernel environment
40 .Fn kenv "int action" "const char *name" "char *value" "int len"
44 function manipulates kernel environment variables.
45 It supports the well known userland actions of getting, setting and unsetting
46 environment variables, as well as the ability to dump all of the entries in
47 the kernel environment.
51 parameter can be one of the following:
52 .Bl -tag -width ".Dv KENV_UNSET"
54 Returns the value associated with the named kernel environment variable.
55 If the variable is not found, \-1 is returned and
60 Only the number of bytes available in
64 Sets or adds a new kernel environment variable.
65 This option is only available to the superuser.
67 Unsets the kernel environment variable
69 If the variable does not exist, \-1 is returned and
74 This option is only available to the superuser.
76 Dumps as much of the kernel environment as will fit in
83 will return the number of bytes required to copy out the entire environment.
88 parameter is the name of the environment variable to be affected.
95 parameter contains either the value to set the environment variable
99 or it points to the location where
101 should copy return data to in the case of
112 will return the number of bytes required to copy out the entire environment.
116 parameter indicates how many bytes of storage
122 function returns 0 if successful in the case of
126 and the number of bytes copied into
132 If an error occurs, a value of \-1 is returned and
135 is set to indicate the error.
142 is not a valid option, or the length of the
147 no value could be found for
154 a user other than the superuser attempted to set or unset a kernel
155 environment variable.
157 bad address was encountered while attempting to copy in user arguments,
158 or copy out value(s).
159 .It Bq Er ENAMETOOLONG
160 the name of a variable supplied by the user is longer than
162 or the value of a variable is longer than
169 This man page was written by
170 .An Chad David Aq davidc@FreeBSD.org .
174 system call was written by
175 .An Maxime Henrion Aq mux@FreeBSD.org .